Browse Topic: Ethanol

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Experimental Study of Warm-Up And Startability Operations in a Spark Ignition Engine Fueled with Ethanol Gasoline Blends2026-01-07387/1/2026
The mitigation of Greenhouse Gas (GHG) emissions poses a major challenge for the transportation sector, driving the need for renewable fuels. Bioethanol represents a promising fuel for Spark-Ignition (SI) engines, combining a reduced life-cycle CO₂ impact with advantageous combustion properties. However, despite its proven performance under steady-state conditions, the widespread of fuels with high ethanol content is still constrained by significant difficulties during engine cold-start operation. This study aims to experimentally assess the effect of ethanol concentration on cold-start performance and warm-up transient behavior of a Naturally Aspirated (NA), Port Fuel Injected (PFI) SI engine. Warm-up tests were conducted at an operating condition of 2000 rpm engine speed and 20 Nm torque using three fuels with increasing ethanol content: commercial gasoline (E5), E30 and E60. In addition, dedicated startability tests were carried out for E60 and neat ethanol (E100) at different initial engine wall temperatures to evaluate fuel sensitivity to thermal conditions during engine start. The experimental results indicate that increasing ethanol concentration has a negligible effect on the overall duration of the warm-up process, while leading to a modest reduction in both engine wall and exhaust gas temperatures. At the same time, E100 displays severe startability limitations at low initial wall temperatures, requiring repeated cranking attempts before stable operation can be achieved. The same startability issues have been observed for E60 but with limited intensity. Two minimum engine wall temperature ranges were identified for reliable cold-start operation at 20-25 °C for E60 and 25-30°C for E100. Overall, these findings experimentally confirm the dominant influence of engine thermal conditions on the reliable startability of ethanol-fueled spark-ignition engines.
Falbo, Luigi, Falbo, Biagio, Perrone, Diego, Castiglione, Teresa
Impact of High Compression Ratios on Ethanol Homogeneous Charge Compression Ignition2026-01-50386/10/2026
Ethanol requires elevated intake temperatures to initiate autoignition in Homogeneous Charge Compression Ignition (HCCI) as a high-octane single-stage fuel. To leverage the high thermal efficiency, low engine-out NOx, and near-zero soot inherent to HCCI with ethanol, a custom piston design was developed to enable high compression ratios (CR) up to 22.5:1. This study investigates HCCI combustion with ethanol at three CRs of 17.5, 20.0, and 22.5 through equivalence ratio and boost sweeps performed to assess the reduction in the intake temperature requirement at high CRs and the emissions and efficiency trade-offs. Results indicate a clear benefit with reduced intake temperature requirements with increasing CR. However, a combustion efficiency penalty was observed at high CRs. Three-dimensional Computational Fluid Dynamics (CFD) simulations were performed using Large Eddy Simulation (LES) coupled with a detailed chemistry model to investigate the underlying mechanisms of the combustion efficiency penalty. CFD results reveal that the combustion efficiency penalty at high CR is primarily due to increased crevice mass trapping unburned or partially oxidized species and a rapid expansion effect inhibiting complete carbon monoxide (CO) oxidation.
Vedpathak, Kunal, Kumar, Mohit, Motwani, Rahul, Datar, Aditya, Gainey, Brian, Lawler, Benjamin
Experimental Investigation on Cold Start and Warm-Up Phases for an Ethanol Fueled SI Engine2026-37-00316/9/2026
The reduction of Greenhouse Gas (GHG) emissions represents a key challenge for the transportation sector, requiring the adoption of renewable fuels capable of ensuring both environmental benefits and compatibility with existing internal combustion engine technologies. In this context, bioethanol emerges as a viable solution for Spark Ignition (SI) engines, offering a low life-cycle CO₂ footprint and favorable combustion characteristics. Nevertheless, despite its well-known advantages under steady-state operation, the widespread use of high-ethanol-content fuels is still limited by critical issues during engine cold start. The aim of this work is to experimentally investigate the influence of ethanol content on cold-start behavior and idle warm-up transient operation of a Naturally Aspirated (NA), Port Fuel Injected (PFI) SI engine. The experimental campaign was carried out under idle conditions using four fuels with increasing ethanol content, namely commercial gasoline (E5), E30, E60, and neat ethanol (E100). Cold-start and full warm-up tests were performed starting from ambient temperature, while additional dedicated experiments were conducted on E100 to evaluate startability under different initial engine wall temperatures. The results show that increasing ethanol content has a limited impact on the overall warm-up duration, while slightly reducing engine wall and exhaust gas temperatures. Conversely, E100 exhibits pronounced startability issues at low initial wall temperatures, requiring multiple cranking attempts to achieve stable idle operation. A minimum wall temperature threshold in the range of 25-30 °C was identified as necessary to ensure reliable cold start with E100. The outcomes of this study provide experimental evidence of the key role played by engine thermal conditions in enabling stable operation of ethanol fueled SI engines during cold start.
Falbo, Luigi, Falbo, Biagio, Perrone, Diego, Castiglione, Teresa
Alcohol-Based Energy Carriers in Transportation: Status, Standards, and Outlook2026-37-00426/9/2026
The global transport sector accounts for approximately 30 % of total final energy consumption and 15.9 % of worldwide greenhouse gas (GHG) emissions, with road transport alone accounting for the largest share at 11.8 %. Decarbonizing this sector requires energy sources that combine scalable generation from renewable sources with compatibility with various modes of transportation and existing infrastructure. Methanol and ethanol emerge as promising alternative energy carriers that can leverage existing logistics infrastructure while reducing dependence on fossil fuels. Global methanol production reached 112 million metric tons, and global ethanol production totaled approximately 93.5 million metric tons in 2024, compared to more than 2 billion metric tons of gasoline and diesel produced annually. The review assesses production pathways and cost trajectories for both alcohols, evaluates fuel requirements across multiple transport modes, including passenger vehicles, light- and heavy-duty vehicles, maritime shipping, aviation, and rail, and provides regulatory frameworks governing fuel standards in six major markets, the European Union, the USA, Brazil, China, Japan, and India. From a technical perspective, the internal combustion engine is examined in greater detail as the energy conversion system, synthesizing current combustion research on engine performance, emissions characteristics, and cold-start behavior. Current standards predominantly accommodate ethanol blending for spark-ignition (SI) engines in passenger vehicle applications, with permitted concentration limits ranging from 3 % in Japan to nearly pure ethanol in Brazil. Methanol applications remain more limited in road applications. In the maritime sector, recent ISO 8217:2024 specifications and International Maritime Organization (IMO) interim guidelines have established frameworks for the use of methanol and ethanol as marine fuels. Aviation remains the most restrictive sector, with alcohol fuels explicitly prohibited in certified aviation fuels due to material compatibility and safety concerns. To unlock the decarbonization potential of methanol and ethanol in the transport sector, coordinated policy support and continued technological innovation will be essential. As production scales and regulatory frameworks mature, both alcohol fuels may play an increasingly central role in the transition toward sustainable mobility.
Fitz, Patrick, Fellner, Felix, Rößlhuemer, Raphael, Härtl, Martin, Jaensch, Malte
The Effects of Ethanol on Combustion in a Super-Lean-Burn Engine2026-01-03034/7/2026
To mitigate global warming, many countries are working toward carbon neutrality. Reducing CO₂ emissions from vehicles requires electrification technologies in hybrid and plug-in hybrid electric vehicles (HEVs, PHEVs) and improving thermal efficiency of internal combustion engines (ICEs). Lean-burn combustion is one approach to improving ICE thermal efficiency. Biofuels and synthetic fuels can also reduce CO₂ emissions in existing vehicles. Ethanol, a bio-derived fuel, is widely used in varying contents worldwide, and its further utilization is anticipated. This study examines the effects of ethanol blending on emissions, thermal efficiency, knocking, and combustion speed in a super-lean-burn engine. Gasoline surrogates with varying ethanol contents were tested at an excess air ratio (λ) of 2.5. Higher ethanol content reduced nitrogen oxides (NOx) emissions due to lower adiabatic flame temperature. Total hydrocarbon (THC) emissions measured by a Flame Ionization Detector (FID) showed a decreasing trend; however, after correction for low sensitivity to ethanol and aldehydes, no significant differences were observed. Thermal efficiency increased with ethanol content, due to reduced cooling losses. Knocking was mitigated by the higher Research Octane Number (RON) from ethanol blending; however, the extent was smaller than in the production engine operating at λ = 1. This mechanism was examined through ignition delay calculations. At λ = 2.5 and in-cylinder pressures above 9 MPa, the 50–90% combustion duration was prolonged, attributable to suppressed ethyl radical formation under lean conditions and a greater influence of the reaction in which methyl radicals consume hydrogen atoms to produce methane under high-pressure conditions.
Sugata, Kenji, Matsubara, Naoyoshi, Yamada, Ryota, Kitano, Koji
Effect of Key Operating Parameters on Homogenous Reactivity-Controlled Compression Ignition Concept with Renewable Fuels03-19-02-00094/1/2026
As part of the dTEC MORE project, sustainable powertrain technologies are being explored, including an alternative combustion concept tailored for engines in serial hybrid powertrains. Among the low-temperature combustion strategies, Reactivity-Controlled Compression Ignition (RCCI) is a prominent approach, offering significant reductions in NOx and soot emissions while enhancing combustion efficiency. The dual-fuel nature of RCCI enables improved control over combustion by utilizing fuels of differing reactivities. In this study, a premixed RCCI strategy was implemented using ethanol as a port-injected low-reactivity fuel and octanol as a directly injected high-reactivity fuel. The experimental work was conducted on a single-cylinder research engine with design features that are found in a gasoline passenger car application. Key combustion parameters such as the start of injection (SOI) of the high-reactivity fuel, injection pressure, intake temperature, lambda, premixed fuel ratio, and valve overlap were varied and evaluated on the engine test bench. The impact of these parameters on performance, combustion stability, and emissions was systematically analyzed. The results were benchmarked against a baseline direct-injected gasoline combustion cycle with a higher compression ratio. The comparison highlights the advantages of the premixed RCCI strategy, particularly in reducing NOx and soot emissions. Additionally, the test results also support in the future steps to model and validate the simulation models, to achieve higher efficiency and lower emissions.
Sundaram, Pravin Kumar, Grundl, Larissa Michaela, Trapp, Christian Thorsten, Tinschmann, Georg
Detecting Fuel Adulteration for Otto-Cycle Vehicle Using Onboard Diagnostics Data and Supervised Machine Learning04-19-02-00082/26/2026
Fuel adulteration affects operating costs, vehicle efficiency, and air pollution. Published estimates suggest it accounts for at least 10% of global sales. The Brazilian National Petroleum Agency (ANP) reported noncompliance in about 23% of inspections in 2023, including 4.3% confirmed adulteration. Quality verification requires laboratory equipment, and sensor-based approaches are often inaccessible to end consumers. This article proposes a sensorless (software-only) method that detects water adulteration in hydrated ethanol from standard Onboard Diagnostics (OBD) data using supervised machine learning, enabling on-vehicle fuel quality monitoring without additional hardware. The proposed approach is evaluated on real-world driving data from two production vehicles with three water adulteration levels in hydrated ethanol (0.0%, 2.5%, and 5.0%), achieving 84.85%–95.85% multiclass classification accuracy. These results indicate that software-only, OBD-based monitoring can provide a practical solution for in-use fuel quality control.
Marchezan, Andre Ricardo, Giesbrecht, Mateus
Flow-Based Corrosion Analysis of NBR-PVC Fuel Hoses in Ethanol-Gasoline Blends2026-28-00792/12/2026
The integration of ethanol into gasoline presents compatibility challenges for automotive fuel-system materials. In this study, the degradation of NBR-PVC fuel hoses exposed to ethanol-gasoline blends (E30, E50, E70, and E100) was investigated under dynamic flow conditions. A custom-designed test rig simulates real-time fuel circulation for 1,200 h. FESEM, ATR-FTIR, and elemental mapping analyses revealed ethanol-induced degradation, including dehydrochlorination, plasticizer leaching, and filler detachment. Among the blends, E30 exhibited the least material degradation, whereas E100 showed significant surface damage and chemical alteration. This study recommends multilayered fuel hose structures with ethanol-resistant inner linings for enhanced durability.
PC, Murugan, L S, Adhitya, G, Arun Prasad, W, Beno Wincy, T, Karthi
Performance Optimization of 2 Cylinder Flex Fuel Engine for Small Commercial Vehicle – A STEP TOWARDS SUSTAINABILITY2026-26-01191/16/2026
Increasing ethanol blending in gasoline is significant from both financial (reducing dependency on crude oil) and sustainability (overall CO2 reduction) points of view. Flex Fuel is an ethanol-gasoline blend containing ethanol ranging from 20% to 85%. Flex Fuel emerges as an exceptionally advantageous solution, adeptly addressing the shortcomings associated with both gasoline and ethanol. Performance optimization of Flex Fuel is a major challenge as fuel properties like knocking tendency, calorific value, vapour pressure, latent heat, and stoichiometric air-fuel ratio change with varying ethanol content. This paper elaborates on the experimental results of trials conducted for optimizing engine performance with Flex Fuel for a 2-cylinder engine used in a small commercial vehicle. To derive maximum benefit from the higher octane rating of E85, the compression ratio is increased, while ignition timing is optimized to avoid knocking with E20 fuel. For intermediate blends, ignition timing is suitably interpolated. Fuel injection pressure is increased to address the higher fuel flow requirement, and a fuel heater is added to address cold starts with E85 fuel. Ethanol content detection is done through software, and by suitable interpolation, fuelling and ignition timing are optimized for the entire range of Flex Fuel in a single calibration file. Engine performance with E20 & E93 fuel is optimized considering all mechanical and thermal limits of the engine through various iterations. The experimental results are analysed using the first principle method.
Kulkarni, Deepak, Malekar, Hemant A, Upadhyay, Rajdip, Katkar, Santosh, Undre, Shrikant
Effect of E20 Fuel on Vehicle Performance Parameters of 694CC Gasoline Engine for Commercial Vehicle Application2026-26-05651/16/2026
In alignment with its carbon reduction commitments, India is transitioning towards higher ethanol-blended fuels, with E20 set for nationwide implementation by 2025. Ethanol is a renewable, domestically produced biofuel produced through fermentation of biomass such as sugarcane, corn. It possesses a higher octane rating and oxygen content compared to conventional gasoline, making it a favorable additive for improving engine performance and reducing emissions. This study investigates the impact of E20 fuel on performance parameters of a 694 cc MPFI , water-cooled, twin-cylinder gasoline engine. For deriving maximum benefits of increased Octane rating of E20, compression ratio was increased to 12.5:1. Experimental analysis was conducted to assess the changes in combustion behavior, brake specific fuel consumption (BSFC), torque output, engine out emissions and thermal efficiency when operating on E20 compared to baseline gasoline (E10). Base results indicate that E20 promotes more efficient combustion, owing to its higher laminar flame speed and elevated oxygen content, leading to a 3–4% improvement in low-end torque across real-world operating speed ranges. Conversely, on-road evaluations reveal a 3–4% fuel economy penalty with E20 relative to E10. Recovering E10-comparable fuel efficiency with E20 necessitates comprehensive engine calibration optimization, supported by targeted hardware modifications. Additionally, the high octane rating of ethanol reduces knock propensity, enabling the adoption of more aggressive ignition timing and higher compression ratios without compromising engine durability. Thermal benefits are also taken into consideration, with a reduction in peak mid-catalyst temperatures by approximately 30–40°C, this enables stoichiometric operation throughout operating range without any enrichment. These improvements suggest that engines calibrated specifically for E20 can be benefited through fuel’s inherent properties to achieve higher thermal efficiency and lower tailpipe emissions. In conclusion, the incorporation of E20 fuel in internal combustion engines shows notable advancements in engine performance and efficiency.
Kulkarni, Deepak, Malekar, Hemant A, Thonge, Ravindra, Kanchan, Shubham
Development of Flex Fuel Engine for Indian Market2026-26-01171/16/2026
This paper presents the methodology and outcomes of modifying a 1.2L naturally aspirated (NA) engine to enable flex-fuel compatibility, targeting optimal performance with ethanol blends ranging from E20 to E100. Ethanol is being increasingly promoted due to its potential to reduce greenhouse gas emissions and to provide an additional source of income for farmers. As per the road map for Ethanol blending released by Govt. of India, there has been continuous increase in blending of ethanol in gasoline. An initial target of 20% ethanol blending in gasoline by April 2025 has already been achieved. This work is in alignment with the broader push for development of flex-fuel vehicles, which necessitates engine adaptations capable of operating on varying ethanol blends. The primary objective was to upgrade the engine, which can give optimum performance with both lower range of ethanol blends starting from E20 as per IS 17021:2018 standard till higher blends of up to E100 as per IS 17821:2022. The engine upgrade included several key modifications such as material upgradation of components directly coming in contact with fuel for ethanol resistance, optimization of the compression ratio, introduction of heated fuel rail system for cold start and redesign of intake camshaft to ensure compatibility and performance with ethanol-blended fuels. Additionally, the engine management system (EMS) was recalibrated with dedicated maps tailored to various ethanol blend levels, enabling efficient and reliable operation across a wide range of fuel compositions
Tyagarajan, Sethuramalingam, Pise, Chetan, Kavekar, Pratap, Agarwal, Nishant Kumar
Material Compatibility Studies of Ethanol Blended Diesel2026-26-01291/16/2026
The Government of India has mandated biofuel blending in automotive fuels to reduce crude oil imports and support the national economy. As part of this initiative, Oil Marketing Companies (OMCs) have begun nationwide blending of E20 fuel (20% ethanol in petrol). Ethanol supply is expected to exceed demand by the end of 2025 due to initiatives like the Pradhan Mantri JI-VAN Yojana. Alternative applications for ethanol are being explored; one promising approach is its use as a co-blend with diesel fuel (ED blends). However, ethanol’s low cetane number and poor lubricity pose challenges for direct use in diesel engines without modifications. ED blends demonstrated reduced emissions while maintaining performance comparable to conventional diesel. To further address concerns related to materials compatibility of ED blends with fuel system components, particularly plastomers that may impact engine durability, a detailed study was conducted using elastomers such as FVMQ, FKM, HNBR, and NBR in accordance with the SAE J1748. Test specimens were immersed in ED blends and conventional diesel at 55°C for 1008 hours. Key physical and mechanical properties were measured before and after the immersion tests. The results revealed that FVMQ, FKM and HNBR demonstrated comparable durability when exposed to ED blends vis-à-vis diesel, whereas NBR performed better only in conventional diesel. SEM analysis of the specimens showed significate surface degradation in NBR, supporting the mechanical test results. Although ED blends exhibited changes in fuel properties such as flash point and water content, the blends remained stable under ambient storage conditions.
Johnpeter, Justin P, Chakrahari, Kiran, Chakradhar, Maya, Arora, Ajay, Prakash, Shanti, Pokhriyal, Naveen Kumar
Correlation of Particulate Matter Species on Gasoline Direct Injection (GDI) Vehicle with Ethanol Blended Gasoline: Real Drive Emissions based Portable Emission Measurement System2026-26-02161/16/2026
On the way to net zero emissions and to cut the oil import bills, NITI Aayog, Government of India and Ministry of Petroleum & Natural Gas (MoP&NG) has rolled out roadmap for ethanol blending in India during 2020-2025. Also, National Policy on Biofuels – 2018, provides an indicative target of 20% ethanol blending under the Ethanol Blended Petrol (EBP) Programme by 2030. Considering these Government’s initiatives current studies were performed on BSVI compliant gasoline direct injection vehicle on RDE compliant route (Route formulated by Indian Oil R&D Centre) with different ethanol blended gasoline fuel formulations i.e., E0 (Neat Gasoline), E10 (10% Ethanol in gasoline) & E20 (20% Ethanol in gasoline). The study aims to determine the compliance of Conformity Factor (C.F.) for ethanol blended gasoline fuel on Direct Injection gasoline engine. The conformity factors were calculated in each case for CO, NOx & PN using moving window average evaluation method. For reference CO2 characteristics curve, CO2 values were measured over Modified Indian Driving Cycle (MIDC) on chassis dynamometer. The study suggests that the use of oxygenated fuel formulations (E10 & E20) impacts tail pipe emissions in a greater way and without any change in the hardware of after treatment devices of the vehicle tail pipe emissions can be reduced. Paper presents RDE as well laboratory mass emissions data collected. However, all the emission values are well below the typical BSVI/Euro6d limits and the C.F for NOx is also below than stated limit of BS_2.0 IRDE (Indian Real Driving Emissions).
Kant, Chander, Arora, Ajay, Saroj, Shyamsher, Kumar, Prashant, Sithananthan, M, Chakradhar, Dr Maya, Kalita, Mrinmoy
Flex-Fuel Technology for India: Challenges, Opportunities, and Compliance with Emerging Emission Norms2026-26-01091/16/2026
The adoption of flex-fuel vehicles (FFVs) in India presents a significant opportunity to reduce dependence on fossil fuels, lower greenhouse gas emissions, and ensure compliance with the country’s evolving emission norms. This paper explores the key aspects of flex-fuel technology in the context of Indian four-wheeler regulations, particularly Bharat Stage VI and potential future emission norms. The study begins with an overview of flex-fuel technology, detailing its advantages and associated challenges. A critical focus is placed on blend identification techniques, which play a vital role in optimizing combustion efficiency and ensuring seamless transitions between different ethanol-gasoline blends. Furthermore, the impact of ethanol blending on various fuel properties is examined, including changes in energy content, latent heat of vaporization, octane number rating, and stoichiometric air-fuel ratio. These factors significantly influence engine performance and emission characteristics, highlighting both challenges and opportunities in meeting emission targets. Finally, the study presents key conclusions on the viability of flex-fuel adoption in India. By addressing the challenges and opportunities associated with the technology, this paper attempts to provide insights for optimizing its implementation in the evolving automotive landscape.
Balasubramanian, Karthick, KR, Prabhakar, Kallahallii Somu, Santhosh Kumar
Calculation of Greenhouse Gas Emissions in CO 2 Equivalent per Hectare of Sugarcane Cultivated for Brazilian Ethanol Production2025-36-019112/18/2025
This study aims to quantify, through Monte Carlo simulation (100,000 iterations), the greenhouse gas (GHG) emissions associated with the complete production cycle of ethanol from sugarcane in Brazil, expressed in kg CO2eq/ha, and to project these emissions over a 20-year horizon. To achieve this, the production cycle was segmented into distinct stages - land use change, soil management and preparation, fertilization, harvesting and straw management, soil carbon sequestration, and industrial processing - and the parameters for each stage were defined based on recent. Three representative scenarios were considered: Worst-case (unsustainable practices involving conversion of native vegetation, high fertilizer dosages, and complete burning of the straw), Typical (conventional practices, with conversion of degraded pastures and sustainable management), and Ideal (best practices, characterized by reduced input dosages, the use of nitrification inhibitors, and high straw retention). The results indicate that, under sustainable practices, ethanol exhibits a significantly lower carbon footprint compared to gasoline, whose typical emissions range between 2.8 and 3.0 kg CO2eq/L. These findings reinforce the potential of Brazilian ethanol to contribute to GHG emission reductions and underscore the importance of adopting sustainable agricultural practices.
Assis, Marcelo Suman Silva, Paula Araújo, Gabriel Heleno de, Baeta, José Guilherme Coelho, Abreu, Pedro Blaso Barbosa de, Filho, Fernando Antonio Rodrigues
Effect of Ultra-High Fuel Injection Pressure on Combustion Characteristics, Engine Performance and Pollutant Emissions of a Multi-Cylinder Engine2025-36-021212/18/2025
The concern about CO2 emissions from commercial vehicles powered with internal combustion engines has been motivating research and development projects to reduce the transportation sector carbon footprint. One of the promising alternatives is the use of biofuels associated with high-efficient internal combustion engines, taking advantage of the current infrastructure of car manufacturers and automotive suppliers, as well as of the potential growth in biofuel production. With the stringent emissions regulations, the use of downsized SI engines for passenger cars has driven the adoption of direct injection technology, enabling the use of different fuel injection strategies such as stratified mixtures and multiple injection events, as well as the increase of the compression ratio as a way to improve engine thermal efficiency. This path also led to a gradual increase in injection pressure, aiming to improve spray formation and reduce the formation of particulate matter. In this sense, the implementation of such technology on the Brazilian flex-fuel engine represents an important path to the transport sector decarbonization. However, the use of hydrous ethanol and gasoline-anhydrous ethanol blends on direct injection systems still demands fundamental research to fully understand the potential benefits and drawbacks of higher fuel injection pressures. Within this framework, this work aims to further understand the effect of using ultra-high fuel injection pressures (up to 1000 bar) on engine performance and pollutant emissions of a multi-cylinder prototype engine. Experimental tests with three different injection pressures confirmed the HC and soot emission reduction, as well as improvement on the engine brake thermal efficiency both when fueled with hydrous ethanol and Brazilian gasohol (blend of 27% anhydrous ethanol in gasoline). Due to the lack of dedicated hardware to pressurize and inject ethanol at ultra-high pressures, the durability of the injection components was a major concern during the experimental campaign.
Antolini, Jácson, Zabeu, Clayton Barcelos, Pires, Gustavo Cassares, Polizio, Yuri
Analysis of Light Duty Vehicle Particulate Matter Emissions Using Scanning Electron Microscopy2025-36-007412/18/2025
Particulate matter (PM), mainly its finer fraction, is among the main atmospheric pollutants present in an urban environment. The relationship between the increase in the concentration of this pollutant and the harm to human health is well established. The main sources of particulate matter in urban areas are mobile sources, which include the exhaust emission from light duty vehicles. This work measured the emission of PM in three light duty passenger vehicles, characterizing it in terms of emitted mass in one “flex” vehicle with port fuel (indirect) injection (PFI), using ethanol and gasohol (mixture of 22% anhydrous ethanol and 78% gasoline, by volume), in another “flex” vehicle with direct fuel injection (GDI), and in a diesel vehicle. In addition to mass measurement, images of the filters used in PM sampling were produced using scanning electron microscopy. The processing of these images made it possible to determine the average PM size, as well as establish a particle size distribution for each vehicle and test fuel. With the same instrument, the presence of some chemical elements present in the sample could be determined, through Energy Dispersive Spectroscopy (EDS) analysis.
Borsari, Vanderlei, Neto, Edson Elpídio, de Abrantes, Rui
Effects of Vehicle Usage on Aldehyde Emissions in Flex-Fuel PFI Engines Using Ethanol2025-36-009812/18/2025
Brazil PL8 regulation has required that manufacturers comply with new emissions levels for all of vehicle life – 0 km up to 160.000 km. On this study, tests found that results between new and used vehicles are remarkably similar except for Aldehydes on Ethanol tests. To better understand this phenomena, two main ideas were considered: first, the engine mileage needed to stabilize aldehydes emissions; and second, the main factors responsible for higher acetaldehyde values on new engines only.
Fernandes, Sarah, Borsari, Marcio, Brondani, Dhouglas
Study of the Performance, Consumption and Range of a Fuel Cell Electric Vehicle Powered by Green Hydrogen2025-36-000712/18/2025
Ethanol is a hydrogen-rich liquid and has a specific energy of 8.0 kWh/kg. In a vehicle, hydrogen storage is done in high-pressure cylinders. The same fundamental technology is used at other fuel cell systems in vehicles such as Toyota Mirai and Honda Clarity. Hydrogen is also introduced into the cell to generate electricity, which will power an electric motor that drives the vehicle. Excess electricity is stored in batteries. The main characteristic of the system described here is that hydrogen can be generated through an additional process in a reformer, installed at a fixed station. The reformer transforms the ethanol stored in the fuel station tank into hydrogen, which can then fuel a vehicle equipped with high-pressure cylinders and fed into the fuel cell. The system, however, emits water vapor, heat, and CO2. This is because carbon dioxide is a byproduct resulting from the transformation of ethanol into hydrogen. According to studies, despite this the system is carbon neutral, considering the total cycle. That is, the CO2 released into the atmosphere is retained by the plantations that are cultivated to produce ethanol. Thus, the carbon is contained in a closed cycle. In addition to ethanol, the reformer can also operate with other fuels such as natural gas, biogas, etc. In view of these facts, we have the following considerations: the use of an electric traction system with a fuel cell powered by reformed hydrogen gas from ethanol can allow greater autonomy for electric vehicles, reducing the dependence on electric charging stations; it can also make a significant contribution to reducing pollutant emissions. Looking at the world situation in the medium term, it may turn out to be an alternative system to the use of internal combustion engines and reduce dependence on fossil fuels.
Fontana, Romeu
Mixing Rules for Accurate Prediction of Physicochemical Properties in Automotive Diesel-Biodiesel-Ethanol Blends2025-36-013512/18/2025
The increasing demand for reduced emissions in the automotive sector has driven research into alternative fuels, including Diesel, Biodiesel, and ethanol blends. This study aims to optimize mixing rules to predict the physicochemical properties of ternary fuel blends, essential for improving engine performance and minimizing emissions. Seven established mixing rules—Kay’s Equation, Semilogarithmic Equation, Grunberg-Nissan Equation, Modified Lederer Equation, Hu-Burns Equation, Power Law, and Polynomial Equation—were evaluated to estimate key properties such as kinematic viscosity, cetane number, cetane index, flash point, pour point, and cloud point. A comprehensive database, sourced from previous literature, included pure fuel properties and blend data for 33 to 101 cases. MATLAB was used to implement nonlinear optimization, adjusting coefficients to minimize error metrics like Mean Absolute Error (MAE), Mean Absolute Percentage Error (MAPE), and Standard Deviation (SD). The physical consistency of the correlations was verified by ensuring that estimated properties followed expected trends. The results identified the best-performing equation for each property, with the Grunberg-Nissan equation providing reliable estimates for viscosity and cetane number, and the Hu-Burns equation excelling in cetane index and cloud point. Additionally, the polynomial equation demonstrated accuracy for flash point. The optimized correlations were validated with independent experimental data, confirming their robustness and suitability for automotive fuel applications. This approach simplifies the selection of fuel compositions, contributing to cleaner fuel formulations and supporting the shift towards sustainable energy solutions.
Tirado, Carlos Andrés Abanto, Lobato, Maria Letícia Costa, Passos, Sthefany Faber, Pradelle, Renata Nohra Chaar, Pradelle, Florian
Numerical Simulation of Additized Ethanol: Impact of Engine Parameters on Combustion, Performance and Emissions2025-36-025012/18/2025
One alternative to fossil fuels is the use of bioethanol in internal combustion engines. However, the application of this renewable fuel in compression-ignition engines is limited due to its low cetane number. This barrier, however, can be overcome by using additives that enhance this property. Consequently, additized ethanol emerges as a promising option with significant potential for decarbonization and improved combustion efficiency. In this context, the present study numerically investigated, using the CONVERGE CFD software, the use of additized ethanol in a compression-ignition internal combustion engine used in marine transportation. As a comparative baseline for each investigated setup, cases involving conventional diesel fuel were also analyzed numerically. The reaction mechanisms used for modeling the combustion of both additized ethanol and conventional diesel were validated against experimental data available in the literature. Di-tert-butyl peroxide (DTBP) was the studied cetane improver used in this study, blended with ethanol at weight fractions equal to 0%, 5% and 10%. In addition to the additive content in ethanol, the study also evaluated, through a sensitivity analysis, the impact of fuel injection strategies, including variations in injection timing (from 6 to 0 degrees before top dead center) and engine load levels (25%, 50%, 75%, and 100%). Key combustion, performance, and emission parameters were analyzed, including ignition delay, heat release rate, thermal and combustion efficiency, and emissions of CO₂, CO, NOX, CH4 and CO2eq. The results indicate that additized ethanol is a viable fuel for compression-ignition engines.
Assis, Guilherme, Sánchez, Fernando Zegarra, Pradelle, Renata Nohra Chaar, Braga, Sergio Leal, Ticona, Epifanio Mamani, Souza Junior, Jorge, Pradelle, Florian
Experimental Investigation of Additive Formulations for Ethanol Use in Compression Ignition Engines Using a Rapid Compression Machine2025-36-018512/18/2025
The transition to renewable fuels is critical to reduce greenhouse gas emissions and achieve carbon neutrality in the transportation sector. Ethanol has emerged as a promising biofuel for compression ignition (CI) engines due to its renewability and low-carbon profile. However, its low cetane number, high latent heat of vaporization, poor lubricity, and corrosive properties severely limit its auto-ignition capability and durable operation under conventional CI conditions. Building upon previous work using a Rapid Compression Machine (RCM) to assess ignition improvers for ethanol, this study explores a broader range of fuel formulations to enhance ethanol-based combustion. A total of nine blends were prepared, consisting predominantly of hydrated ethanol (50-80% by volume), combined with 5-25% biodiesel and up to 5% of a commercial ignition improvers. The biodiesel component acted both as a co-solvent and as a combustion stabilizer, particularly under cold-start conditions. Tests were carried out under both hot and cold-start conditions, across compression ratios ranging from 25:1 down to the ignition failure limit. To ensure equal injected energy input, injected fuel mass was adjusted based on the Lower Heating Value (LHV) of each blend. High-resolution pressure transducers and high-speed optical imaging were employed to provide direct experimental insights into the combustion process, validate thermodynamic trends, and support comparative assessments of ignition behavior across different blends and compression ratios to evaluate key combustion parameters. The results indicate that blends enriched with both biodiesel and ignition additives, particularly E900B50A50, E925B50A25, and E925B25A50, significantly improved auto-ignition performance, enabling complete and stable combustion under compression ratios higher than 23. Uniform flame front propagation was observed across all injector nozzles, indicating complete combustion and effective fuel–air mixing, which are essential for maximizing thermal efficiency and minimizing unburned emissions in CI engine operation.
Bacic, Denise Amato, Sánchez, Fernando Zegarra, Ticona, Epifanio Mamani, Pradelle, Renata Nohra Chaar, Santos Coelho, Lucas dos, Mota, Crislane Almeida Pereira da, Pradelle, Florian
Ignition Delay and Combustion Efficiency Analysis of Marine Diesel-Biodiesel-Ethanol Blends in a Rapid Compression Machine2025-36-013112/18/2025
In alignment with the International Maritime Organization’s 2023 GHG Strategy and the Paris Agreement, this study investigates the viability of ternary blends of marine diesel, biodiesel, and ethanol as low-emission marine fuels. While previous studies have established the physicochemical behavior and storage stability of such blends, particularly the co-solvency role of biodiesel to prevent phase separation, limited data exists on their combustion performance under engine-relevant conditions. This work addresses this gap through a series of controlled experiments conducted in a Rapid Compression Machine (RCM), which enables the approximate a single-cycle combustion in a compression ignition engine. The tested blends included varying proportions of ethanol (up to 20% in volume) in a blend of fossil fuel with 25% of biodiesel (25%), and their combustion were evaluated across different injection timings. Key performance metrics such as ignition delay, maximum temperature and pressure, thermodynamic efficiency, and combustion efficiency were calculated and analyzed. Results demonstrated that increasing ethanol content led to longer ignition delays due to ethanol’s low cetane number and high latent heat of vaporization, which in turn affected heat release dynamics and efficiency. Thermodynamic efficiency peaked at early injection timings, reaching up to 49.41% for B25E20 blends with intermediate timing (3 mm), while combustion efficiency also improved with higher ethanol content, especially at early and late injection points. Notably, B25E20 achieved the highest combustion efficiency among all blends tested and for all injection timing. These findings highlight the potential of biodiesel–ethanol–diesel blends for reducing maritime emissions while optimizing energy utilization, provided that injection parameters are carefully tuned. The study also reinforces the need for further refinement of predictive models to capture the nonlinear behavior of these fuels, supporting the broader transition to sustainable marine propulsion technologies.
Lobato, Maria Letícia Costa, Sánchez, Fernando Zegarra, Ticona, Epifanio Mamani, Pradelle, Renata Nohra Chaar, Braga, Sergio Leal, Coelho, Lucas Dos Santos, Pradelle, Florian
Energy and Exergy Analysis of Ethanol Steam Reforming with an Emphasis on Thermal Efficiency for Sustainable Mobility Applications2025-36-013312/18/2025
The growing demand for sustainable energy and the need to reduce greenhouse gas emissions have driven interest in low-carbon hydrogen production. Ethanol steam reforming (SR) offers a promising on-board H2 source by exploiting ethanol’s renewability and liquid-fuel convenience. This study presents an integrated energy and exergy analysis of ethanol SR across 573 to 923 K and steam-to-ethanol (S/E) ratios from 1 to 4 using Gibbs free energy minimization in MATLAB to predict equilibrium compositions and thermal duties. Energy analysis shows the heating duty rising from 0.0311 kWh/mol ethanol at 573 K (S/E = 1) to 0.0521 kWh/mol at 923 K (S/E = 4). Reforming duty shifts from -0.0075 to +0.2426 kWh/mol, while cooling duty recovers between -0.0219 and -0.0727 kWh/mol. The net energy balance transitions from strongly endothermic below 650 K to near-neutral at 700 to 750 K for S/E > 2, and becomes exothermic above 800 K, reaching +0.2463 kWh/mol at 923 K. Exergy analysis reveals that heating stage irreversibilities increase modestly from 0.015 to 0.035 kWh/mol ethanol with higher temperature and S/E. In contrast, reforming-stage destruction falls sharply from 0.125 to 0.017 kWh/mol, and cooling-stage destruction decreases from 0.038 to 0.024 kWh/mol as conditions become more favorable. Total exergy destruction peaks at 0.071 kWh/mol near 713 K (S/E ≈ 4) before declining to 0.060 kWh/mol at 923 K (S/E = 4). Exergetic efficiency correspondingly rises from 1.5 % to over 70 % across this range. The shift in dominant exergy losses from reforming at low temperatures to cooling at high temperatures highlights key opportunities for advanced heat-recovery integration. Optimal operation between 850 K and 900 K with elevated S/E ratios maximizes hydrogen yield while minimizing energy quality losses. These insights inform reactor design and thermal management strategies for sustainable mobility, demonstrating that tailored temperature and steam loading can substantially improve the performance of on-board ethanol steam reforming systems.
Apaza, Jerson Bequer Urday, Pradelle, Florian, Braga, Sergio Leal, Sánchez, Fernando Zegarra, Guzman, Juan Jose Milon
Performance Analysis of Methanol- Ethanol Blend Fuel in a Spark-Ignition Flex-Fuel Engine2025-36-014812/18/2025
Flex-fueled vehicles (FFV) dominate the Brazilian market, accounting for over 75% of the national fleet. Ethanol fuel is widely used, primarily in the form of hydrated ethyl alcohol fuel (HEAF). Given the similar physicochemical properties of ethanol and methanol, fuel adulteration is a growing concern, often involving the addition of anhydrous ethanol, methanol, or even water to hydrated ethanol. These adulterants are visually imperceptible and can only be detected through analyses conducted by regulatory agencies using specialized instruments. However, they can significantly affect vehicle performance and accelerate engine component deterioration. The experiment was performed with a small displacement 3-cylinder port fuel injection flex-fuel engine on an engine test bench (dynamometer) and compared when fueled with ethanol and methanol. Data acquisition included combustion pressure, spark plug temperature, torque, air-fuel ratio, fuel flow, spark maps, and the overall effects of methanol adulteration on combustion. The results indicate that engines designed and calibrated to operate with hydrated ethanol exhibit different combustion behaviors when methanol is present in the fuel mixture. Methanol increases combustion pressure and temperature inside the chamber, creating a highly corrosive environment due to both the elevated temperature and the chemical properties of methanol. Fuel consumption increased when methanol was used in the engine calibrated for ethanol. The findings highlight the potential risks associated with fuel adulteration, emphasizing its impact on engine durability, vehicle fuel economy, and maintenance costs.
Mascarenhas, Giovana Rebellato, Gomes, Ederson, Cruz, Diego, Duque, Edson Luciano
A Comprehensive Study on the Effect of Compression Ratio and Pilot Injection Strategy on Alcohol Compression Ignition03-18-07-004411/13/2025
Achieving compression ignition (CI) with ethanol, a renewable fuel, comes with challenges because of its much lower cetane number compared to diesel. Additionally, ethanol’s high cooling potential and high volatility compared to diesel also offer challenges and opportunities to achieving robust, high-efficiency CI. Increasing the compression ratio (CR) and expanding the injection strategy beyond a conventional close-coupled pilot-main diesel injection strategy can help overcome these challenges. This work experimentally tested ethanol CI with several different injection strategies with CRs ranging from 16.3 to 22.3. The results showed that in homogeneous charge CI (HCCI), increasing the CR improved thermal efficiency but incurred a combustion efficiency penalty. In any CI concept, increasing the CR lowered the required intake temperature to achieve ignition. Using close-coupled pilot injections is an effective way to achieve ethanol CI, but it was also shown that HCCI-like intake stroke “pilot” injections offer a new avenue of ethanol CI. With a 25% pilot injection during the intake stroke, stable ethanol CI was achieved at 6 bar IMEPg with an intake temperature of 330 K using a CR of 20.0. There was a ~1 percentage point thermal efficiency benefit and ~50% reduction in NOx, though there was also a 1 percentage point combustion efficiency penalty. At lower loads, it was more beneficial to run with more fuel in the intake stroke pilot. Finally, experiments showed that the NOx emissions decreased from 5.75 g/kWh to 3.43 g/kWh at 6 bar IMEPg by increasing the CR from 16.3 to 20.0 and reducing the intake temperature by 60 K. Even with matched intake temperature, the engine-out NOx was 4.57 g/kWh with a CR of 20.0. CFD simulations showed that this was due to the higher CR having a more rapid expansion process, cooling the diffusion flames more rapidly.
Gainey, Brian, Vedpathak, Kunal, Kumar, Mohit, Lawler, Benjamin
Experimental Investigations on Lean Burn Spark-Ignition Engine Using Alcohol-Gasoline Blends2025-28-021311/6/2025
Alcohol fuels are regarded as a feasible approach to address rising energy demands and reduce the dependency on fossil fuels, with ethanol and methanol emerging as a promising renewable fuel for spark-ignition engines. In this research work, tests were performed on a spark ignition engine altered from a diesel engine that employs ethanol/methanol-gasoline blend as fuel operating under lean conditions. The experiments were conducted at 10.5:1 compression ratio and 1500 rpm under full throttle condition with three fuel blends namely M10 (10% of methanol+ 90% gasoline), E10 (10% of ethanol+ 90% gasoline), E5M5 (5% of each ethanol and methanol+ 90% gasoline). Investigational results reveals that alcohol-gasoline blends displayed low COV of IMEP. Furthermore, the alcohol-gasoline mixtures enhanced the peak in-cylinder pressure owing to improved flame speed and flammability limits. Adopting lean-burn operation and high compression ratio can efficiently improve combustion attributes in an alcohol-gasoline fuel operated spark ignition engine.
Devunuri, Suresh, Porpatham, Dr. E
Effect of EGR and Ethanol additive on Performance and Emission Characteristics of Diesel Engine Fuelled with Rubber Seed Biodiesel Blends2025-28-022411/6/2025
Alcohol is being considered as an alternative to traditional fuels for compression ignition engines due to their oxygen content and biomass origin. Although alcohol generally has lower cetane numbers, which makes them more favorable for premixed combustion, they also offer potential for lowering emissions in internal combustion engines, particularly when combined with strategies such as exhaust gas recirculation (EGR). This research focuses on enhancing the performance of a single-cylinder, four- stroke diesel engine by introducing ethanol into the intake port during the intake phase. Diesel and rubber seed biodiesel were used as primary fuels and were directly injected into the combustion chamber. The findings indicated that adding ethanol to rubber seed biodiesel, along with 10% EGR, led to improved brake thermal efficiency and a reduction in NOX emissions. The ethanol injection timing and duration were optimized for effective dual-fuel operation. At full engine load, the highest brake thermal efficiency recorded with a 20% ethanol energy share was 34% for diesel, 31.16% for B20 with EGR, and 31.15% for B20 without EGR. Furthermore, NOX emissions were reduced by 25.44% and 26.08% for B10 with EGR and B20 with EGR, respectively, at peak thermal efficiency. On the downside, increasing ethanol contribution raised HC, CO₂, and smoke emissions across all loads for both B10 and B20 with EGR. Additionally, B10 and B20 with EGR experienced higher peak cylinder pressures and maximum rate of pressure rise, while ethanol uses also resulted in shorter combustion duration and increased heat release rates.
Saminathan, Sathiskumar, G, Manikandan, Bungag, Joel Quendangan, T, Karthi
Performance and Emission Characteristics of CI Engines Using Ethanol- Cottonseed Biodiesel Blended with Aluminum Oxide Nanoparticles2025-28-021011/6/2025
As global energy demands continue to grow and environmental challenges intensify, Biodiesel stands out as an environmentally sound and technically feasible alternative to curb fossil fuel use and emissions. This study provides an in-depth analysis of the performance and emissions profile of a compression ignition (CI) engine running on a renewable diesel fuel blend made from ethanol and cottonseed (Cs) combinations enhanced with aluminium oxide (Al2O3) nanoparticles. The experimental fuel blends, consisting of 10%, 20%, and 30% cottonseed biodiesel with 5% ethanol and remaining with conventional diesel, were analyzed under varying engine load conditions. The inclusion of ethanol improved fuel atomization due to its lower viscosity and higher volatility, while Al2O3 nanoparticles acted as advanced combustion catalysts, promoting enhanced oxidation rates and thermal efficiency. Among the blends, B10 (10% cottonseed biodiesel) exhibited superior performance metrics, achieving a brake thermal efficiency (BTE) of 32.8%, marginally below diesel’s 33.44%, and a 1.6% rise in brake-specific fuel consumption (BSFC). The analysis of emissions highlighted a considerable decline in nitrogen oxide (NOₓ) emissions. 7.14%, 10.71%, 14.29% recorded for B10, B20, B30 blends respectively. Carbon monoxide (CO), unburned hydrocarbons (HC), and smoke opacity showed a small uptick. The overall emissions profile confirmed substantial environmental benefits, establishing B10 as the most balanced blend for optimized engine performance and minimized pollutant emissions. This research paves the way for future developments in renewable biodiesel blends, offering advancements in fuel economy, cleaner combustion, and overall emission reductions, while addressing the increasing demand for sustainable energy sources.
T, Karthi, G, Manikandan, Saminathan, Sathiskumar, M E, Chandhuru, S, Bavanya, S, Arunkumar
Computational Investigation on a Boosted Uniflow Scavenged Direct-Injection Combustion Engine (BUSDICE) with Alcohol Fuels2025-32-002711/3/2025
Alcohol fuels, produced from renewable energy sources, are considered a crucial solution for achieving life-cycle carbon neutrality in internal combustion engines. The Boosted Uniflow Scavenged Direct-Injection Combustion Engine (BUSDICE) exhibits significant potential for high thermal efficiency with an aggressive downsizing design. In this study, a computational investigation was carried out to assess the spray mixing and combustion characteristics of BUSDICE fuelled with methanol and ethanol, compared with gasoline, under a high-load condition. The injection duration of methanol and ethanol is significantly longer than that of iso-octane, leading to incomplete evaporation. The mixture exhibits an “outer-rich, central-lean” stratification pattern due to the short mixing time and swirl flow transportation for all three fuels. However, the prolonged injection of methanol induces stronger turbulence, which can enhance the local mixing. The spatial mixture stratification, particularly near the spark-local area, has a strong influence on the initial kernel development and flame propagation. Consequently, methanol exhibits a shorter ignition delay than ethanol under the same spark timing, leading to faster flame propagation attributed to a richer equivalence ratio around the spark plug. Nevertheless, the ignition and combustion performance of ethanol can be improved by advancing the spark timing. The spark timing study reveals that alcohol fuels can operate under high load without knocking, whereas iso-octane requires retarded ignition timing to prevent knocking. As a result, methanol and ethanol provide a better IMEP and ITE than iso-octane under high-load conditions. From an emissions perspective, due to their low carbon-to-hydrogen (C/H) ratio and high oxygen content, unburnt hydrocarbon emissions decrease significantly when using alcohol fuels, especially methanol, for which these emissions are almost zero. However, the soot of ethanol shows a slight increase than iso-octane, due to the highly stratified mixture and incomplete combustion. Additionally, the NOx of ethanol and methanol increases due to the higher combustion temperatures than iso-octane. Overall, the results highlight the strong potential of alcohol-fuelled BUSDICE engines as compact and sustainable solutions for small-displacement powertrains, offering high thermal efficiency and substantially reduced pollutant emissions.
Feng, Yizhuo, Lu, Enshen, Dong, Shuo, Keshtkar, Hossein, Wang, Xinyan, Zhao, Hua
Study of Combustion Characteristics of a Two-Stroke Opposed Piston Engine using Low-Octane Fuels2025-32-002811/3/2025
Various fuels are being considered as the next generation of carbon neutral fuels, including methanol, ethanol, and SAF. These have widely different ignition properties. Methanol and ethanol are high-octane fuels, so there are no major problems with their use in gasoline engines. However, SAF is a hydrocarbon with a large molecular weight, so it has a fundamentally low octane rating and is not easy to use in SI engines. In order to put carbon-neutral fuels of various properties into practical use, it is effective to develop a technology that allows fuels with low octane to be operated in SI engines. Therefore, in this study, basic research was conducted on the combustion of fuels with low octane using PRF fuel in opposed-piston engines. Opposed piston engines are characterized by their light weight due to the absence of a cylinder head, low S/V ratio due to the ultra-long stroke, reduced cooling loss due to the long stroke, and reduced vibration due to the offsetting of the reciprocating inertial forces of the left and right pistons, resulting in high efficiency and output. In addition, one of the disadvantages of low-octane fuel is that it tends to auto-ignite, but combustion under high residual gas conditions has the effect of suppressing fuel auto-ignition, and by using a 2-stroke engine with a high percentage and high concentration of residual gas and locally high temperatures, auto-ignition is suppressed and low The use of two-stroke engines with high residual gas content and high concentration and high local temperatures can be expected to suppress auto-ignition and allow the use of low-octane fuels.
Yamazaki, Yoshiaki, Okawara, Ikumi, Liu, Jinru, Iijima, Akira
Lignin as Cetane Booster for Methanol and Ethanol2025-24-00759/7/2025
Low carbon, though poorly igniting (i.e., low cetane) fuels, such as methanol, ethanol, and ammonia, are gaining momentum in the maritime fuel market. The most adopted strategy to address the fact that these fuels will not, under typical two-stroke marine engine conditions, auto-ignite, is to co-inject a pilot fuel, such as (very) low sulfur marine fuel oil, which does auto-ignite and furthermore doubles as a spark of sorts for the poorly igniting base fuel. This so-called dual-fuel approach is costly and cumbersome. Cetane boosters are known to improve ignitability of alcohol fuels to the point that a pilot fuel is no longer required. In our earlier research, we found some indication that lignin model compounds could likewise improve the ignitability of alcohols. This paper builds further on this hypothesis, now using commercially available lignin rather than model compounds. Auto-ignition behavior of methanol and ethanol was investigated with up to 10 wt% of therein solubilized lignin in both an Advanced Fuel Ignition Delay Analyzer (AFIDA) and (two-stroke) spray combustion chamber. The results suggest that lignin indeed improves the ignitability of both alcohols and that pilotless auto-ignition is possible under realistic two-stroke marine engine conditions when 10% of (alcohol-soluble) lignin is blended into ethanol, with the associated cetane number being close to 10.
Sementa, Paolo, Tornatore, Cinzia, Catapano, Francesco, Lazzaro, Maurizio, Iannuzzi, Stefano, Kouris, Panos, Boot, Michael
Machine Learning-Enhanced Combustion Modelling: Predicting Ethanol Effects in a Single-Cylinder Research Engine2025-24-00269/7/2025
Recent studies highlight the urgent need to reduce greenhouse gas (GHG) emissions to mitigate the impacts of global warming and climate change. As a major contributor, the transport sector plays a vital role in these efforts. Ethanol emerges as a promising fuel for decarbonising hard-to-electrify propulsion sectors, thanks to its sustainable production pathways and favourable physical and combustion properties, such as energy density, rapid burning velocity, and high knock resistance. This work proposes a methodology to enable the possibility of replicating the combustion behaviour of ethanol in a 1D CFD simulation environment representative of a single-cylinder research engine. Spark-ignition combustion is simulated through the Eddy Burn-Up combustion model previously calibrated for standard fossil gasoline. The combustion model features a laminar flame speed neural network, trained and tested through reference chemical kinetics simulations. The combustion model showed great accuracy in replicating key combustion metrics, highlighting its predictive capability while switching fuel kinds. Eventually, knock occurrence was evaluated by employing the Livengood-Wu induction time integral. The model was adjusted by the induction integral multiplier to align the knock predictions to the normalised experimental Mean Amplitude Pressure Oscillation value. The latest remains always below 1, meaning that the engine can be run at maximum combustion efficiency without knock occurrence even at maximum load.
Ferrari, Lorenzo, Sammito, Giuseppe, Fischer, Marcus, Cavina, Nicolò
A Life Cycle Assessment of Potential Pathways to Increase Sustainable Aviation Fuel Yields through CO 2 Upgrading Co-located with Corn Ethanol Production13-06-03-00239/4/2025
Alcohol-to-jet (ATJ) upcycling of ethanol to sustainable aviation fuel (SAF) is an attractive emerging pathway for SAF production, especially in the US Midwest with large-scale corn ethanol production. Only 39% of the corn carbon is converted to ethanol, 20% is emitted as CO2. Capturing the CO2 to produce additional ethanol or SAF directly can increase the carbon yield. To guide technology selection, this work used life cycle assessment for several CO2-to-SAF production pathways. Additionally, improvements for corn ethanol production were explored by replacing natural gas burners with heat pumps for corn drying, which reduced the carbon intensity of corn ethanol by nearly 16%. But subsequent upgrading of the ethanol to SAF is only 4.5–20% better than conventional aviation fuel. By contrast, CO2-based alternative routes to SAF fared better, reducing carbon intensities between 83% and 90%. Gas fermentation of CO2 to ethanol with subsequent ATJ upcycling to SAF was contrasted to Fischer–Tropsch conversion of CO2 to SAF. Both streams require CO2 conversion to CO, which can be produced using reverse water–gas shift or solid oxide electrolyzer cells. The Fischer–Tropsch synthesis shows a higher reduction in carbon intensity (up to 90%) compared to ATJ (up to 84.4%). For other impact categories, such as ozone depletion, ecotoxicity, and the like, the differences are of similar magnitude. Capturing CO2 locally at the bioethanol factory and converting that CO2 to ethanol might overall be preferable with a fermentation process that is quite like bioethanol production compared to Fischer–Tropsch synthesis for which products require a new transportation infrastructure. The aviation fuel yield from ATJ can reach 90%, higher than the 50–70% yield from Fischer–Tropsch synthesis, with gasoline and diesel fuel as major by-products for which markets will shrink in the future. Overall, ATJ appears to be the best choice for CO2-to-SAF using the synergy with corn ethanol factories for quick launch.
McCord, Stephen, Talsma, Sam, Bouchard, Jessey, Zavaleta, Victor Gordillo, He, Xin, Sick, Volker
Ethanol Fuel as Enabler for High-Efficiency and Low-Soot Combustion in Dual-Fuel and Blend Modes03-18-04-00287/16/2025
Global climate initiatives and government regulations are driving the demand for zero-carbon tailpipe emission vehicles. To ensure a sustainable transition, rapid action strategies are essential. In this context, renewable fuels can reduce lifecycle CO2 emissions and enable low-soot and NOx emissions. This study examines the effects of renewable ethanol in dual-fuel (DF) and blend fueling modes in a compression ignition (CI) engine. The novelty of this research lies in comparing different combustion modes using the same engine test rig. The methodology was designed to evaluate the characteristics of various injection modes and identify the inherent features that define their application ranges. The investigation was conducted on a single-cylinder engine equipped with state-of-the-art combustion technology. The results indicate that the maximum allowable ethanol concentration is 30% in blend mode, due to blend stability and regulatory standards, and 70% in DF mode, due to combustion stability and emission concerns. DF mode produces higher THC and CO emissions compared to blend or conventional diesel combustion (CDC) modes. However, ethanol consistently reduces smoke formation across all engine test conditions and fueling modes. At ultra-low-NOx levels (0.5 g/kWh), smoke emissions remain below 0.5 FSN. At the highest ethanol fraction in DF mode (70%), smoke emissions decrease to very low levels (−0.1 FSN), with improvements in thermal efficiency and CO2 emissions. DF mode requires specific injection control strategies to mitigate THC and CO emissions. In blend mode, the highest ethanol fraction (30%) results in CO2 and soot reductions, with CO and THC emissions comparable to CDC.
Belgiorno, Giacomo, Ianniello, Roberto, Di Blasio, Gabriele
Computational Investigation of Advanced Compression Ignition with Wet Ethanol in an OP-2S04-19-01-00026/30/2025
Alcohol fuels have inherent properties that make them suitable candidates to replace conventional fossil fuels in internal combustion engines by reducing the formation of harmful emissions such as lifecycle carbon dioxide (CO2), nitrogen oxides (NOX), and particulate matter (PM). There is an increasing amount of work to use fuels such as ethanol or methanol in mixing-controlled compression ignition (MCCI) as a replacement for diesel fuel. However, employing these fuels in a strictly MCCI strategy results in an evaporative cooling penalty that lowers indicated fuel efficiency. This work proposes the use of an advanced compression ignition (ACI) strategy with a high autoignition resistant fuel, where a fraction of the fuel is premixed and autoignited in conjunction with a fraction of fuel that is burned in a mixing-controlled manner to achieve diesel-like efficiencies with significant emission reductions. A computational model for MCCI with diesel and wet ethanol in an opposed piston two-stroke (OP-2S) engine was validated against experimental data. Diesel and wet ethanol MCCI were then compared at a similar operating condition, where it was seen that wet ethanol provided a significant reduction in NOX emissions but resulted in a lower indicated efficiency. A triple injection strategy to enable ACI is then proposed by redesigning one of the injectors to enable compression stroke injections. The injector included angle, the injection split fractions, and injection timings of the triple injection strategy were varied to understand the impact of each on combustion performance and emissions. An optimal triple injection strategy based on simulation data was approximated and then simulated to compare to conventional diesel (i.e., MCCI with diesel) and MCCI with wet ethanol. ACI demonstrated a 3.5% point efficiency improvement over MCCI with wet ethanol, resulting in an efficiency that was the same as conventional diesel while still demonstrating nearly a 4 times reduction in NOX emissions.
O’Donnell, Patrick Christopher, Gainey, Brian, Bhatt, Ankur, Huo, Ming, Lawler, Benjamin
Influence of Fuel Surface Tension and Viscosity on Internal Flow Bubble Formation and Atomization in Flash Boiling Sprays2025-01-02216/16/2025
Flash boiling atomization is considered a promising atomization technique for combustion applications in automotive powertrains. It can potentially address the deteriorated atomization issue for alternative fuels (such as methanol) in internal combustion engines. However, it has been observed that flash boiling spray atomization for methanol fuels is not as effective as that for traditional alkane-based fuels. This work aims to explain such phenomena using transparent nozzles to reveal the impact of internal vaporization on external spray breakups. Three different working fluids, including methanol, ethanol, and pentane, are tested with elevated temperatures. The flow patterns and external liquid breakup are shown with the high-speed imaging technique. It is found that the internal phase change of the base working fluid is suppressed when ethanol or methanol is used instead of pentane. Consequently, the external liquid breakup is also hindered due to insufficient vapor phase inside the nozzle. It is held that increased surface tension and viscosity have made the nucleation process more challenging compared with typical gasoline fuels.
Zhang, Yijia, Li, Yilong, Wang, Shangning, Zeng, Tingxi, Xu, Min, Hung, David, Li, Xuesong
Experimental Analysis of Performance and Durability Using Ethanol 27% Fuel Blend in a Turbocharged Gasoline Direct Injection Engine2025-01-02456/16/2025
India aims to achieve 20% ethanol blending (E20) in petrol by 2025 under its National Biofuels Policy to reduce carbon emissions, enhance energy security, and support the agricultural economy. Building on this, E27 (27% ethanol in gasoline) is being evaluated as an advanced mid-level blend to further lower greenhouse gas emissions and reduce reliance on fossil fuels. This study investigates the performance, emissions, and combustion characteristics of a turbocharged gasoline direct injection (TGDI) engine using E27 fuel over 20,000 km in real-world driving conditions, as part of a broader research program accumulating over 100,000 km across multiple vehicle categories. Key findings indicate that E27 achieves an optimal balance of emissions reduction and performance, with NOx and THC emissions decreasing by 12% and 5%, respectively, compared to E10, while CO and CO₂ levels remained stable, reflecting ethanol’s oxygenation effect and lower carbon intensity. Power output and acceleration improved slightly due to ethanol’s higher-octane rating and improved combustion efficiency. Oil degradation and wear remained within acceptable limits, confirming E27's suitability for regular use without requiring engine modifications. The findings suggest that E27 blended fuel has potential and can significant future ethanol adoption strategy, which will also supporting its 2030 carbon reduction targets. Further research should focus on optimizing calibration in engine for different ethanol blends as the current study has focused on E10 compliant vehicle’s long-term durability, and performance of the with higher fuel blends aligning with real time usage pattern.
D R, Vigneshwar, Bhakthavachalu, Vijayabaskar, Muralidharan, M.
Techno-Economic Analysis of an Integrated E-Methanol Production Plant Utilizing First and Second Generation Biomass Resources2025-01-01826/16/2025
This study presents a comprehensive techno-economic assessment (TEA) of an integrated e-methanol production system building upon previously published foundational research utilizing Aspen Plus modeling for e-methanol production from sugar cane and sugar beet biomass. The established integrated system converts biomass into ethanol through fermentation and synthesizes e-methanol using both captured CO2 and syngas derived from biomass residue gasification. This approach maximizes CO2 and biomass utilization, promoting a circular carbon economy. The TEA quantifies capital expenditures (CAPEX), operational expenditures (OPEX), and levelized costs of Methanol (LCOM), providing a detailed economic analysis of the potential for commercializing e-methanol. A sensitivity analysis evaluates the impact of feedstock prices and Technology Readiness Levels (TRL), identifying key leverage points affecting financial viability. The study aims to explore the potential of utilizing existing agricultural infrastructure for sugar cane and sugar beet to minimize setup costs and expedite market readiness. The system’s capacity to reduce carbon emissions significantly aligns with global sustainability goals. This study provides strategic recommendations for scaling e-methanol production and improving its economic viability in the renewable energy sector. The sensitivity analysis particularly aids in developing robust strategies to mitigate risks associated with economic and market fluctuations.
Fernandes, Renston Jake, Shakeel, Mohammad Raghib, Nguyen, Ducduy, Im, Hong G., Turner, James W.G.
Enabling Neat Alcohol Combustion in a Heavy-Duty Diesel Engine with Exhaust Rebreathing13-06-03-00225/23/2025
In this study, a strategy for MCCI combustion of a novel alcohol fuel is demonstrated. The novel fuel, “GrenOl”, is the result of the catalytic upgrade of sustainable ethanol into alcohols of higher molecular weight. The composition of GrenOl includes approximately 70% 1-butanol, 15% 1-hexanol, and 5% 1-octanol by mass, resulting in a cetane number around 18. In order to achieve mixing-controlled compression ignition with GrenOl, an exhaust rebreathing strategy is employed. In this strategy, the exhaust valve reopens for a part of the intake stroke, inducting hot exhaust into the cylinder and preheating the fresh air. This study investigates the feasibility of operating with such a valve strategy from idle to peak torque. At idle, the primary challenge is ensuring stable combustion by inducting adequate exhaust to achieve ignition. Under load, when cylinder temperatures are higher, the primary challenge is ensuring sufficient air is inducted to achieve the target torque. It was found that a modest exhaust rebreathing valve strategy could ensure stable combustion with diesel-like emissions and efficiency from idle to peak torque. Coefficient of variation of IMEP as low as 2% was achieved at idle, matching diesel idle stability despite the very low cetane number of the fuel. At medium load, indicated specific fuel consumption was as low as 235 g/kWh, and engine-out indicated specific NOx emissions were as low as 4 g/kWh. Peak torque was attained despite the volumetric efficiency penalty imposed by exhaust rebreathing. These results demonstrate the feasibility of operating a diesel engine on neat, sustainable, ethanol-derived fuel over the entire engine operating map with minimal well-defined design modifications. Future work should extend these findings to multicylinder engines and challenging cold start conditions.
Trzaska, Joseph, Xu, Zhihao, Boehman, André L.
Influence of Exhaust Gas Recirculation on Knock in a Spark Ignition Engine Fueled with Ethanol–Gasoline Blends03-18-03-00194/28/2025
Exhaust gas recirculation (EGR) is widely used in spark ignition engines to reduce throttling losses, decrease exhaust gas temperatures, increase efficiency, and suppress knock. However, the effectiveness of EGR as a knock suppressor is dependent on the fuel type and operating condition. In this study, the effectiveness of EGR to suppress knock was tested with E10, E30, E50, E75, and E100 at a moderately boosted condition. It was found that EGR was effective at suppressing knock with E10, but high EGR rates were required to achieve a knock suppression effect with E30 and E50. No knock suppression effect was observed with E75 and E100 across all tested EGR rates. With E30 and E50, EGR that was passed through a three-way catalyst was more effective at suppressing knock at all EGR rates. Chemkin modeling with neat ethanol revealed that nitric oxide enhanced ignition by increasing the hydroxyl radical concentration in the end gas, resulting in earlier auto-ignition. Directly seeding nitric oxide in the intake system with neat ethanol resulted in an increase in knock intensity, which required a knock-limited CA50 retard of 3.5 crank angle degrees with 660 ppm of nitric oxide.
Gandolfo, John, Gainey, Brian, Lawler, Benjamin
Optimization of Combustion Efficiency and Conversion Efficiency of Catalytic Converter in Spark-Ignited Engine using Taguchi Methods Robust Optimization Technique for Flex Fuel Application2024-32-01234/18/2025
Flex fuel vehicles (FFV) can operate effectively from E5 (Gasoline 95%, ethanol 5%) fuel to E100 (Gasoline 0%, ethanol 100%) fuel. It is necessary to meet the performance, drivability, emission targets and regulatory requirements irrespective of fuel mixture combination. This research work focuses on optimizing the combustion efficiency and conversion efficiency of catalytic converter of a spark-ignited less than 200 cc engine for FFV using Taguchi methods robust optimization technique. The study employs an eight-step robust optimization approach to simultaneously minimize engine out emissions and maximize catalytic converter efficiency. Six control factors including type of fuel, catalyst heating rpm, lambda (excess-air ratio), injection end angle, lambda controller delay, and ignition timing are optimized. Four noise factors like compression ratio, clearance volume, catalyst noble metal loading, and catalyst aging are also considered. Through approximately 100 physical experiments on a chassis dynamometer, the impact of control factors on engine out emissions and conversion efficiency has been evaluated. Signal-to-noise (S/N) ratios has been calculated for THC and NOx engine-out emissions (combustion efficiency) and their conversion efficiency. Based on the S/N ratio, optimal levels has been chosen for different control factors. The study predicts significant gains in THC conversion and combustion efficiency while modest improvements for NOx conversion. Confirmation runs has been conducted to validate the prediction. The confirmation run yielded slightly lower gains when compared to prediction. The study acknowledges limitations due to control factor interactions but highlights the substantial reduction in experimentation time and effort compared to traditional EFI system calibration methods. Ultimately, the research demonstrates the effective application of robust optimization techniques to meet emission regulations for flex fuel vehicles without significantly increasing production costs. This approach streamlines the optimization process, reducing the number of experiments required and addressing production variations efficiently.
Vaidyanathan, Balaji, Arunkumar, Praveenkumar, Shunmugasundaram, Palani, Murugesan, Manickam, Jayajothijohnson, Vedhanayagam
Experimental Investigation of n-C7H16/Ethanol Blended Fuels on Auto-ignition and Flame Propagation in High Temperature/Pressure Constant-Volume Combustion Vessel2024-32-00504/18/2025
This study aims to investigate the effect of ethanol blends on flame propagation and auto-ignition under high pressure and high temperature conditions. Experimental investigations are conducted using n-C7H16 / ethanol blends at various blending ratios (0, 5, 10, 20, 40, 70, and 100 vol%). The blends are premixed with air at stoichiometric ratios and ignited centrally in a cylindrical constant-volume combustion chamber (20-mm inner diameter, 80-mm long) under elevated temperature (500 K) and pressure (1.0 MPa) conditions. The results show that auto-ignition occurs at an ethanol blend ratio of 10% or less and ceases above 20%. Increasing the ethanol blend to 70% results in a slight change in flame propagation speed, with a noticeable delay at 100%. The pressure measurements show a peak of about 5.6 MPa at a blend ratio of 5%, which gradually decreases with increasing ratios. High-pass filtering reveals the maximum pressure fluctuation amplitude at the 5% blend ratio, indicating increased knocking intensity at certain ethanol blend ratios. These results clearly indicate that, for the cases of larger ethanol content over 10%, auto-ignition, and therefore, the pressure increase by combustion can be suppressed. On the other hand, for the cases of less ethanol content than 10%, flame propagation can be accelerated, which leads to the rapid compression of the unburned mixture, and thus, the large amplitude strong auto-ignition.
Tateishi, Tokua, Yamaguchi, Riki, Shimokuri, Daisuke, Terashima, Hiroshi, Hara, Takaya, Honda, Yuya, Kawano, Michiharu
Study on Flex Fuel Compatible Coatings for Automotive Fuel Tank2024-32-00764/18/2025
Reducing CO2 emissions is now a major focus in India heading towards net zero emissions by 2070. India is the 3rd largest automobile market in the world and the transportation sector is the 3rd largest CO2 emitter. In this direction, it is necessary to reduce the carbon footprint from the automobile sector to combat climate change. The adoption of sustainable biofuels such as ethanol will enable us to reduce emissions, as ethanol is carbon neutral fuel. However, vehicle manufacturers are facing challenges in manufacturing flex fuel compatible parts in the vehicle mainly fuel systems. Ethanol has both nonpolar and polar bonds, making it miscible to both gasoline and water, thereby water contamination is inevitable in ethanol blend fuels. In addition, control of ethanol contamination by sulfates and chlorides during ethanol production is challenging. Thus, ethanol blend fuels are considered more corrosive and tendency towards deposit formation than normal gasoline fuels. Design and development of corrosion resistant and flex fuel compatible materials for fuel systems are important without compromising the functional requirements. In fuel systems, fuel tank is one of the major parts, which acts as a reservoir for fuel supply and needs to have good chemical and corrosion resistance. This paper describes the comparative study of three different coating systems of single layer coating with and without topcoat on top of steel sheet to withstand up to 85% ethanol fuel blends. In all these coated samples, base metal used is low carbon steel sheet which is commonly used for automotive fuel tank application. The fuel tank internal corrosion study is conducted using test fuel as aggressive ethanol blend fuel at coupon level as per SAE J1747. The test fuel has been selected to simulate the effect of possible contamination in the real usage condition and to provide accelerated corrosion test. The selection criteria used for the evaluation are base material corrosion, pitting, weight loss, formation of reaction products and its elution behavior into the test fuel. No pitting, perforation and weight loss were observed in all the coating systems after the test. Base material corrosion was encountered in only 2 coating systems and reaction products were observed as deposits in all coating systems for higher ethanol blend test fuels. The reaction products were analyzed in SEM-EDS and their elution effect into the fuel was studied under both static and dynamic fluid conditions.
Pandi, Dinesh Babu, Shanmugam, Gomathy Priya, Nagarkatti, Arun, Gopal, Manish, Anbalagan, Prathap
Influence of Methanol-to-Gasoline Fuel Formulation on Knock Propensity and Flame Speed2025-01-84004/1/2025
Drop-in gasoline fuels that originate from renewable, low-net-carbon sources, such as methanol-to-gasoline (MTG), are an important bridge in the transition between traditional fossil fuels and electrification of the transportation sector. The composition of these fuels can be tuned by adjusting the settings of the chemical processes used to create them, which can be leveraged to formulate optimized fuels for higher knock resistance or higher flame speed. This study investigated how the distribution of hydrocarbon classes and molecular structure of a renewable MTG gasoline surrogate affected knock and flame speed using chemical kinetic modeling. The original MTG surrogate was modified by increasing the relative amount of a certain hydrocarbon class while the concentration of other hydrocarbon classes is reduced equally. Increasing normal- and iso-alkanes increased reactivity and penalized octane sensitivity, olefins increased octane sensitivity while keeping the research octane number constant, and increasing cyclo-alkanes or aromatics decreased reactivity with the fuel being more sensitive to cyclo-alkanes. To optimize octane rating, short normal-alkanes and long, highly-branched iso-alkanes are preferred, with octane rating being very sensitive to the structure of iso-alkanes. Increased branching also improves octane rating for cyclo-alkanes, olefins, and aromatics. Regarding flame speed, normal-alkanes tend to increase flame speed at engine-relevant conditions because they form radicals that accelerate the flame. However, aromatics and cyclo-alkanes, which are promising octane boosters, showed lower flame speeds. Based on this understanding, an optimized MTG was formulated and compared against the effect of ethanol blending on the original MTG, with the optimized fuel showing similar performance as MTG with 52.5%vol ethanol. Chemical kinetic analyses showed that the chemistry that controls octane rating is different from that that controls flame speed, opening the door to fuels that simultaneously improve both knock and deflagration characteristics.
MacDonald, James, Lopez Pintor, Dario, Matsubara, Naoyoshi, Kitano, Koji, Yamada, Ryota
Modelling and Simulation of a Formula 1 Power Unit for 2026 and Predicting Formaldehyde Levels2025-01-80044/1/2025
The transition to fully sustainable fuels, like ethanol, for Formula 1 power units in 2026 introduces challenges related to engine performance and emissions. The lower energy content of these fuels can have a negative impact on power output, while the increased levels of formaldehyde produced during combustion pose an environmental concern. This study aims to evaluate engine performance while meeting the FIA’s 2026 regulations using numerical simulations and to develop a method for estimating formaldehyde emissions produced during combustion. An F1 power unit model was developed in GT-Suite, incorporating all relevant regulations for 2026. The model was validated against literature data for combustion characteristics, such as laminar and turbulent flame speeds, and friction losses. Additionally, compliance with operational limits, such as energy flow restrictions, was confirmed. Suitable elementary and global reaction mechanisms for formation and destruction of formaldehyde were identified from literature and incorporated into the fully developed predictive combustion model in GT-Suite. The study evaluated engine performance between 7000 and 15000 rpm for maximum power output for E20 fuel. Estimated formaldehyde levels using chemical kinetic modelling were compared against experimental data obtained from literature for E50 and E100 at different engine loading conditions. Rate-determining reaction steps were identified for partial engine loads. This work provides a scheme for optimizing the performance of the 2026 F1 engine and predicting the formaldehyde emissions levels.
Fuss, Nadine, Samuel, Stephen
The Effect of Nitric Oxide (NO) on the Reactivity of Ethanol and Gasoline: An Experimental Study2025-01-84134/1/2025
Achieving stable HCCI combustion requires specific in-cylinder boundary conditions. Trace residual species, such as nitric oxide (NO), can have an impact on the reactivity, and thus the combustion stability, of different fuels in HCCI. This study investigates the effects of nitric oxide (NO) on the reactivity and combustion stability of ethanol and gasoline in a single-cylinder HCCI engine. The promoting and inhibiting impact of NO on iso-octane’s ignition delay time are available in the literature; nevertheless, as a baseline study, these effects on the autoignition of gasoline were documented in this work. For ethanol, the NOx concentration seeded in the intake air varied from 0-1000 ppm while maintaining a constant combustion phasing (CA50 at 7.5 CAD) and a global equivalence ratio of 0.34. Ethanol exhibited a linear reduction in intake temperature, decreasing by 47 K with 927 ppm NO. For gasoline, a 225-ppm increase in NO reduced the intake temperature required for HCCI by 40 K. However, gasoline showed a non-linear response, attributed to different autoignition characteristics of the fuels. Ethanol's reactivity enhancement is linked to NO's role in converting less reactive HȮ2 radicals into more reactive OḢ radicals in a chain propagation step. Therefore, NO significantly influences combustion stability, introducing a potential “runaway” effect on combustion phasing in advanced combustion modes. In traditional mixing-controlled combustion, NO affects the kinetically controlled pilot heat release, altering the premixed heat release spike. However, the ignition delay correlation for ethanol widely used in the literature failed to capture these reactivity enhancement effects, as the Livengood Wu integral predicted the same autoignition threshold for ethanol with varying NO concentration.
Bhatt, Ankur, Gandolfo, John, Vedpathak, Kunal, Lawler, Benjamin, Gainey, Brian
Mixing-Controlled Combustion of Ethanol Enabled by Prechamber Ignition (PC-MCC): A Preliminary Experimental Demonstration04-18-02-00123/17/2025
This experimental study presents preliminary investigations of prechamber-enabled mixing-controlled combustion (PC-MCC) at −2 bar brake mean effective pressure (BMEP) and 2200 rpm with fuel-grade ethanol (E98). Experimental results are conducted on a prechamber retrofitted single-cylinder Caterpillar C9.3B test engine. First, a series of prechamber-only experiments were conducted with a motored engine to evaluate the salient combustion trends in response to relevant prechamber operating parameters. Under firing conditions, the prechamber operating strategy was assessed with respect to the impact on ignition assistance of direct-injected E98 and overall engine performance. The preliminary results indicate the jet-induced ignition process is robust and prompts diffusion combustion of E98 at diesel-like boundary conditions. The effect of external exhaust gas recirculation (EGR) on the residual tolerance of the prechamber combustion process was also investigated and showed stable combustion in both the main chamber and prechamber up to 30% EGR. Experiments were also conducted with the stock diesel engine for baseline comparison. At matched combustion phasing, mixing-controlled combustion of ethanol enabled by prechamber ignition was able to achieve heightened gross thermal efficiency while simultaneously reducing NOx and practically eliminating smoke emissions relative to diesel combustion. In addition, the covariance of load and standard deviation of combustion phasing was diesel-like and less than 2% and 1 CAD, respectively.
Zeman, Jared, Dempsey, Adam
Jet-Induced Compression Ignition (JICI)—Application of Spark-Assisted Compression Ignition (SACI) in a Combustion System with Active Pre-Chamber03-18-01-00091/17/2025
The application of short burn durations at lean engine operation has the potential to increase the efficiency of spark-ignition engines. To achieve short burn durations, spark-assisted compression ignition (SACI) as well as active pre-chamber (PC) combustion systems are suitable technologies. Since a combination of these two combustion concepts has the potential to achieve shorter burn durations than the application of only one of these concepts, the concept of jet-induced compression ignition (JICI) was investigated in this study. With the JICI, the fuel is ignited in the PC, and the combustion products igniting the charge in the main combustion chamber (MC) triggered the autoignition of the MC charge. A conventional gasoline fuel (RON 95 E10) and a Porsche synthetic fuel (POSYN) were investigated to assess the fuel influence on the JICI. Variations of the relative air/fuel ratio in the exhaust gas (λex) were performed to evaluate both the occurrence of the JICI and the dilution capability. To assess the sensitivity of the JICI, variations of the engine speed and the engine load were performed. When using RON 95 E10, a shift from a conventional PC combustion to the JICI was observed between λex = 2.3 and λex = 2.5. The variations of the engine speed and the engine load revealed an increased JICI intensity when the engine speed decreased and when the engine load increased. When using POSYN, no JICI was observed. The occurrence of the JICI was correlated to the knock resistances of the fuels, i.e., the lower knock resistance of RON 95 E10 yielded the JICI, whereas the higher one of POSYN did not. At λex = 2.8, applying POSYN resulted in an increase of the burn duration of 5.5°CA, which was a relative increase of 41%, compared to the use of RON 95 E10 due to the absence of the JICI in case of POSYN. However, the application of POSYN resulted in the highest net indicated efficiency (ηi,net). In particular, the application of RON 95 E10 yielded a maximum of ηi,net = 41.5% at λex = 2.6, whereas using POSYN resulted in a maximum of ηi,net = 42.6% at λex = 2.2 due to the higher knock resistance of POSYN.
Burkardt, Patrick, Günther, Marco, Villforth, Jonas, Pischinger, Stefan
Analysis of Biodiesel Production Worldwide: The Solutions and Consequences Related to Its Addition to Diesel2024-36-010112/20/2024
The goal of this research is to better understand the methodologies for manufacturing biodiesel worldwide and the main raw materials used in its production. We aim to compare the solutions established by relevant countries with those used in Brazil, identifying their advantages and disadvantages. Our primary areas of interest include the United States, Indonesia, and Europe, where we will analyze the solutions and, whenever possible, understand the commercial and political interests involved. We will highlight aspects related to sustainability in the production, transportation, and use of biodiesel. The methodology is based on research from recent publications and news, organized into graphs to facilitate analysis and comparison. Next, we will also examine the consequences of the solutions adopted in Brazil, envisioning future scenarios and recommended paths. In the short term, biodiesel is expected to be replaced by renewable diesel (also known as green diesel in some regions, including Brazil), which can also be produced from biomass. Ethanol is likely to be a global solution in the short to medium term, with hydrogen expected to take the lead in providing renewable energy. In the long term, around 2050, the use of fossil fuels for power generation should be significantly reduced, and technologies for energy storage, along with clean, renewable, and sustainable energy sources, should prevail.
Labigalini, Marcio Roberto, Barreto, Gilmar
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