Browse Topic: Dimethyl ether (DME)

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Investigation of Transient High Current Ignition for Lean Mixture in Spark Assisted Compression Ignition2025-01-039010/07/2025
Lean burn combustion is an effective strategy to reduce the in-cylinder temperature. Hence reduce NOx emissions and increase the thermal efficiency of the system. One essential aspect of successful combustion is the flame kernel initiation and development. However, as the fuel-air mixture becomes leaner, challenges arise in achieving a stable flame kernel initiation and a moderate speed of flame propagation. This empirical research aims to investigate the impact of the transient high current ignition strategy on flame kernel development, flame propagation and auto-ignition timing of lean Dimethyl Ether (DME). In this work, a rapid compression machine is employed at engine-relevant conditions, a pressure of ~15 bar and temperature of ~650K. Spark-assistance is applied at the end of compression to enable a spark-assisted compression ignition combustion mode. The spark event is initiated by a transient high current ignition system, which includes a traditional transistorized coil ignition
Asma, Sabrina, Yu, Xiao, Jin, Long, Tjong, Jimi, Zheng, Ming
Optimization of CI Engine Operation with DME on an FTP Cycle2025-01-039410/07/2025
Fuels that can be produced in a sustainable manner are of high interest because they can provide an essential step toward net zero emissions vehicles. This study examines the combustion of one such fuel, Dimethyl Ether (DME), in a compression ignition, 4-cylinder, 2.2L engine. Testing was conducted using the Federal Test Procedure (FTP) certification cycle from the US Environmental Protection Agency (EPA). Different sets of calibration maps were designed to target low-NOx (30-50ppm) by using high EGR and intake throttle and high-NOx (approximately 1000ppm) using no EGR. An intermediate, mid-NOx calibration was also evaluated. Varying calibration approaches yielded total integrated engine out emissions ranging from 118 to 145gCO2/km, all below the 191gCO2/km from the baseline diesel. The corresponding NOx+UHC and CO emissions were also evaluated. The mid-NOx calibration was overall more favorable, as it met TIER 3-Bin 20 emissions requirements with the current efficiencies of the base
De Ojeda, William, Wu, Simon (Haibao), Harrison, Christopher, Hall, Carrie, Arslan, Elaheh, Pulpeiro Gonzalez, Jorge
Model-Based Optimization of Diesel/OMEx Fuelled CI Engine under Multiple Blending Conditions2025-24-003809/07/2025
The search for alternative solutions for vehicle electrification, while reducing the carbon footprint during the transition to green mobility, leads to the investigation of electro-fuels (e-fuels) in conventional internal combustion engines. Leveraging previous research, the present study focuses on the optimisation of a Compression Ignition (CI) engine combustion control in response to the use of the Oxymethylene Dimethyl Ethers (OMEx) blended with conventional diesel. The selected e-fuel is the OME3, which is expected to be used as a drop-in solution and to easily achieve a reduction in soot emissions due to both its high oxygen content and lack of direct carbon bonds in its molecular structure. To verify its potential, a 1D single-cylinder CI multi-zone engine model has been exploited to simulate various diesel/OME3 blends in a wide engine operating range. The first step deals with the evaluation of performance and emissions to demonstrate the differences, particularly in terms of
Foglia, Antonio, Cervone, Davide, Frasci, Emmanuele, Arsie, Ivan, Polverino, Pierpaolo, Pianese, Cesare
Assessing the Performance of a Modified Fuel Injection System–Equipped Dimethyl Ether-Fueled Genset/Tractor Engine04-18-03-001405/21/2025
Ethers are emerging as suitable mineral diesel replacements. A customized mechanical fuel injection system was used to investigate the dimethyl ether–fueled genset/tractor, and ~75% rated engine load was achieved over diesel. The in-cylinder pressure rise rate was about half for the dimethyl ether engine. However, the lower pressure generated in the high-pressure dimethyl ether line reduced brake thermal efficiency for the dimethyl ether engine. Dimethyl ether engines emitted lower nitrogen oxide emissions than baseline diesel except at higher loads and reduced nozzle opening pressure. Carbon monoxide emissions increased due to prolonged and incomplete combustion at higher loads with reduced nozzle opening pressure. Blowby gas leakage was lower for dimethyl ether than for baseline diesel engines. Overall, the genset/tractor engine could perform satisfactorily using a customized fuel injection system and will help achieve carbon neutrality from the various sectors using this technology.
Agarwal, Avinash Kumar, Pal, Manojit, Valera, Hardikk
Experimental Quantitative Analysis of Spray Velocity Field Characteristics of Four Compression-Ignition Engine Oxygenated Alternative Fuels03-18-03-002105/10/2025
As the suitable substitutes for diesel in compression-ignition (CI) piston engines, hydrotreated vegetable oil (HVO), polyoxymethylene dimethyl ethers (PODEs), and bio-aviation fuel (BAF), among other oxygenated alternative fuels have been widely recognized due to higher cetane values. To explore the in-cylinder fuel spray dynamics and subsequent fuel–air entrainment of these fuels, experimental studies on near-field and full-field spray characteristics were carried out by the diffuser back-illumination imaging (DBI) method within a constant-volume chamber. The local velocity was inferred by momentum flux conservation and Gaussian radial profile assumption, and the dimensionless Jet number was introduced to qualify the strength of interaction within two-phase flow. It was found that the initial spray transitions from a “needle” to a larger spray head structure as injection pressure rises, especially with PODE3-5 exhibiting a stable “mushroom” structure due to its higher surface tension
Chen, Houchang, Jiang, Junxin, Hu, Yong, Yu, Wenbin, Zhao, Feiyang
Optimization of the Numerical Spray Modeling for Polyoxymethylene Dimethyl Ethers for Combustion Prediction in CONVERGE2025-01-502604/03/2025
Different approaches are undertaken to mitigate the impact of the transport sector on climate change. Alongside electrifying powertrains, sustainable e-fuels such as polyoxymethylene dimethyl ethers (OME) are considered a promising bridging technology for different applications. However, this requires that the engines are optimized for the new fuels. Accordingly, this study aims to optimize the numerical spray modeling of OME in CONVERGE. Based on the KH–RT break-up model, the spray simulations of three different commercial injectors for heavy-duty applications are analyzed regarding the predictability of the liquid and gaseous penetration lengths and the total simulation time. A sensitivity analysis is conducted for the turbulence model, mesh size, and spray parameters prior to optimizing the spray model and validating it with experimental results. While each parameter individually influences the different phases of the injection event, the sensitivity analysis reveals that the break
Zepf, Andreas, Härtl, Martin, Jaensch, Malte
Investigation of Dimethyl Ether Injection Profiles in High-Pressure Direct Injection System2025-01-846404/01/2025
The majority of transportation systems continue to rely on internal combustion engines powered by fossil fuels. Heavy-duty applications, in particular, depend on diesel engines due to their high brake efficiency, power density, and robustness. Despite significant advancements in diesel engine technology that have reduced emissions and improved efficiency, complex and costly after-treatment systems remain necessary to meet the stringent emission regulations. Dimethyl ether (DME), which can be produced from various renewable feedstocks and possesses high chemical reactivity, is a promising alternative for heavy-duty applications, particularly in compression ignition direct injection engines. Its high reactivity, volatility, and oxygenated composition offer significant potential to address emission challenges while reducing reliance on after-treatment systems. However, DME’s lower energy density requires adjustments in injection parameters (such as injection pressure and duration) or
Cong, Binghao, Leblanc, Simon, Tjong, Jimi, Ting, David, Yu, Xiao, Zheng, Ming
Characterization of Dimethyl Ether (DME) Spray Using ECN Spray D Under Engine-Relevant Conditions2025-01-845704/01/2025
This research experimentally investigates the spray vaporization of high-pressure dimethyl ether (DME) using a single-hole research injector focusing on nominal operating conditions from the Engine Combustion Network (ECN). DME is a synthetic alternative to diesel fuel, offering both high reactivity and potential reductions in particulate emissions. Because DME only features half of the energy density of diesel fuel, a specifically designed fuel system with a high mass flow rate to meet the energy delivery requirements is needed. The unique physical properties of DME, including higher vapor pressure and lower viscosity, introduce challenges like cavitation and unique evaporation characteristics that deviate from typical diesel fuel. These features are likely to lead to differences in fuel mixing and combustion. This study aims to provide detailed experimental data on DME spray characteristics under engine-like conditions, helping the development of predictive CFD models for optimal
Yi, Junghwa, Wan, Kevin, Pickett, Lyle, Manin, Julien
Energy Conversion Efficacy of Neat Dimethyl Ether Combustion with Heat Release Characterization and Emission Analysis2025-01-841704/01/2025
Dimethyl ether (DME) is widely regarded as a suitable energy source for compression ignition power systems because of its high reactivity. It has been widely reported that DME possesses a significantly low propensity to form soot, hindering the innate NOx-soot trade-off encountered with diesel fuel operation. Beyond the fuel-borne oxygen content of DME, its unique physical properties present a contrasting combustion behavior which may be advantageous to direct injection systems, especially concerning the mixing-controlled combustion mode. This work aims to detail the energy conversion efficacy of DME through heat release characterization and exhaust emission speciation. The tests were controlled within a single-cylinder research engine with an off-board high-pressure injection system to handle liquified DME up to 1000bar. To mitigate interference in fuel additives over the combustion behavior, the high-pressure fuel system specifically managed neat DME. The in-cylinder pressure was the
Leblanc, Simon, Cong, Binghao, Leach, Jace, Yu, Xiao, Reader, Graham, Zheng, Ming
Design of a High-Pressure Fuel System for Use with Dimethyl Ether2025-01-844104/01/2025
The paper documents the modeling and experimental work on a common rail fuel injection system for Dimethyl Ether, a potential diesel substitute with a low carbon intensity signature. The DME fuel system is deployed on a light duty 2.2L compression ignition engine. The paper describes the injector optimization to shift to higher flows to account for the lower heating value and density of the DME when compared to diesel. The type of the injection system used for the DME application is an advanced rendering of the Common rail noted for a one-piece piston-needle injector construction and a solenoid driven spill valve featuring a pressure balanced poppet. A dedicated high-pressure fuel pump designed to pressurize DME is used. The design results in a fast acting open and close injection event, reduced leakage, with reduced cavitation in the fuel injector volume. Design parameters for system optimization included fill and spill orifices, needle lift, bias spring, and injector hole size. The
De Ojeda, William, Wu, Simon (Haibao)
Diesel Engine Performance and Combustion Imaging Analysis of Gas-to-Liquid and Polyoxymethylene Dimethyl Ether Blended Fuels04-18-02-001002/12/2025
To reduce carbon dioxide emissions from automobiles, the introduction of electric vehicles to the market is important; however, it is challenging to replace all existing IC engine vehicles with electric ones. Consequently, there is increasing anticipation for the use of carbon-neutral fuels, such as e-fuels. This study investigates the effects of GTL (gas-to-liquid), as a substitute for e-fuel, produced from natural gas via the Fischer–Tropsch synthesis method and polyoxymethylene dimethyl ether (OMEmix) produced from methanol, on engine performance. Additionally, combustion image analysis was conducted using a rapid compression and expansion machine (RCEM). GTL fuel combusts similarly to conventional diesel fuel but has slightly lower smoke emissions because it does not contain aromatic hydrocarbons. Further, its high cetane number results in better ignition properties. During the combustion, unburnt hydrocarbons and smoke are generated in the spray flame interference region near the
Shibata, Gen, Yuan, Haoyu, Yamamoto, Hiroya, Tanaka, Shusuke, Ogawa, Hideyuki
Experimental Study on Combustion and Emission Characteristics of a Two-Stroke Engine applying PODE/Methanol Blends Direct Injection2025-01-711201/31/2025
In order to realize the Paris Agreement, which aims to strengthen the global response to climate change, conventional internal combustion engines (ICE) need to contribute to reducing carbon emissions and improving thermal efficiency. More importantly, in the face of energy shortages, it is urgent to search for sustainable fuels. Poly-oxymethylene dimethyl ethers (PODE) and methanol are both regard as important low-carbon, alternative fuels due to their high oxygen content. Using PODE can overcome the characteristics of methanol as a low-reactivity fuel with a low cetane number and poor ignition properties. In this study, the combustion and emission characteristics of PODE/methanol blends were investigated in a two-stroke direct injection engine. Firstly, the performance of the engine under pure PODE (P100) and PODE/methanol blends (P50) was compared. The results show that at BMEP of 0.31 MPa and injection timing of -8°CA ATDE, P50 blends have lower CO2, CO, NOX and THC emissions than
Dong, Pengbo, Sun, Zhuohan, Wang, Qingyang, Wang, Yang, Cui, Jingchen, Zhang, Zhenxian, Long, Wuqiang
Emission and Economic Characteristics of Diesel/PODE Blended Fuel in Actual Road Driving2025-01-711501/31/2025
Diesel/Polymethoxy Dimethyl Ether (PODE) blend fuel can significantly reduce emissions from diesel engines. However, emission levels often vary due to high transients during real-world driving conditions. To evaluate the emission and economic performance of diesel/PODE blend fuel, this study analyzed the real-world driving behavior of heavy tractors using different blend ratios (0%, 20%, 30%) across urban, suburban, and expressway road sections, in compliance with the national VI emission standard. Based on Vehicle Specific Power (VSP) bins, the study compared carbon monoxide, carbon dioxide, nitrogen oxide, particulate matter, and fuel consumption rates between pure diesel and blended fuels, providing insights into their performance under varying driving conditions. In addition, specific emissions of pollutants, effective fuel consumption, and effective thermal efficiency for urban, suburban, and expressway sections, as well as for the entire test process, are analyzed to quantify the
Liu, He, Yang, Yajing, Farooq, Muhammad Shahid, Liu, Shenghua, Wei, Yanju
Comparison of Different Injector Nozzles for the Utilization of Polyoxymethylene Dimethyl Ethers2024-01-429711/05/2024
Oxygenated substances are a promising approach in the field of alternative fuels. A current example of such a fuel are Polyoxymethylene Dimethyl Ethers (OME). With their physical and chemical properties, alternative fuels like OME pose new challenges for diesel engine injection systems. As the heating value is low compared to conventional Diesel fuel, measures must be taken to increase the amount of fuel injected. Possible solutions include increasing the nozzle hole diameter, the injection pressure, and the number of nozzle holes. All mentioned adaptions have an influence on the mixture formation and make it necessary to examine the injection process in detail also with regard to phenomena such as cavitation. In this study, three passenger car Diesel injector nozzles are compared, two of which are adapted in terms of nozzle hole diameter (increase by 20%) and number of nozzle holes (increase from 8 to 12) in order to increase the mass flow rate of fuel to the required elevated level
Riess, Sebastian, Fuchs, Thorsten, Strauß, Lukas, Günthner, Michael, Wensing, Michael
Emission Characteristics of TCR Diesel Fuels in Comparison to Diesel Fuels Derived from other Sources2024-01-428911/05/2024
In this work we demonstrate the influence of different refined TCR refining diesel fuels on emission, power and efficiency in comparison to reference Diesel fuel (homologation fuel for Euro 6 emission testing), hydrotreated vegetable oil (HVO) and a blend of poly(oxymethylene)dimethyl ether (OME3) with reference Diesel. The emission characteristics of such TCR fuels used in a production type Diesel engine with modern common rail system has up to now not been tested. The comparison was performed at an engine test bench equipped with a Hatz 4H50 TIC direct injection common rail Diesel engine. For different engine operation points exhaust gas emissions and particulate matters were measured and the results analyzed.
Seeger, Jan, Taschek, Marco
Combustion and Emissions Comparison between a Diesel and a Dimethyl Ether (DME) Off-Highway Compression Ignition Engine2024-01-270011/05/2024
Dimethyl ether (DME) is a promising substitute for diesel as a fuel in heavy-duty engines. This article presents the comparison between a diesel- and a DME-powered compression ignition engine. The diesel-powered version was initially characterised at a range of operating points before being converted to operate on DME. This was achieved by replacing fuel system components with bespoke DME-compatible engine parts. An off-board fuel pressurisation and conditioning system was designed to replace the existing high-pressure fuel pump, while maintaining all other engine hardware and components. Engine behaviour, in terms of combustion and emissions on both fuels was examined. Firstly, the effect of varying recirculated exhaust gas (EGR) concentration at constant excess air ratio, combustion phasing (CA50) and equal fuel delivery rate (by energy input) was interrogated. DME combustion was significantly faster, as combustion duration was reduced by around 30%, in some cases, when comparing to
Apostolou, Christos, Elliott, Thomas, Rutledge, John, Butcher, Daniel, Long, Edward, Spencer, Adrian
Letter from the Focus Issue Editors03-17-07-004910/12/2024
Letter from the Focus Issue Editors
Lakhlani, Hardik, Kumar, Vivek, Wenbin, Yu, Bagga, Kalyan, Gundlapally, Santhosh, Di Blasio, Gabriele, Splitter, Derek, Rajendran, Silambarasan
TOC99-06-05-0TOC10/10/2024
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Tobolski, Sue
Effects of Dimethyl Ether and Propane Blends on Knocking Behavior in a Boosted SI Engine03-17-07-005606/12/2024
Dimethyl ether (DME) is an alternative fuel that, blended with propane, could be an excellent alternative for exploring the use of fuels from renewable sources. DME–propane blends are feasible for their comparable physicochemical properties; these fuels may be pressured as liquids using moderate pressure at ambient temperature. Adding a proportion of DME with a low octane number to a less reactive fuel like propane can improve the combustion process. However, the increased reactivity of the mixture induced by the DME could lead to the early appearance of knocking, and this tendency may even be pronounced in boosted SI engines. Hence, this study experimentally analyzes the effect of E10 gasoline (baseline) and DME–propane blends, with varying proportions of DME in propane ranging from 0% to 30% by weight, in increments of 5% on knocking tendency, combustion characteristics, gaseous emissions, and particle number concentration, under different intake pressure conditions (0.8, 0.9, 1.0
Soto, Lian, Han, Taehoon, Boehman, Andre L.
Dimethyl Ether Biogas Reactivity-Controlled Compression Ignition for Sustainable Power Generation with Low Nitrogen Oxide Emissions03-17-07-005404/22/2024
Biogas (60% methane–40% CO2 approximately) can be used in the reactivity-controlled compression ignition (RCCI) mode along with a high-reactivity fuel (HRF). In this work dimethyl ether (DME) that can also be produced from renewable sources was used as the HRF as a move toward sustainable power generation. The two-cylinder turbocharged diesel engine modified to work in the DME–biogas RCCI (DMB-RCCI) mode was studied under different proportions of methane (45–95%) in biogas since the quality of this fuel can vary depending on the feedstock and production method. Only a narrow range of biogas to DME ratios could be tolerated in this mode at each output without misfire or knock. Detailed experiments were conducted at brake mean effective pressures (BMEPs) of 3 and 5 bar at a speed of 1500 rpm and comparisons were made with the diesel–biogas dual-fuel and diesel–biogas RCCI modes under similar methane flow rates while the proportion of CO2 was varied. The DMB-RCCI mode exhibited superior
Gopa Kumar, S., Mohan, Aneesh, Ramesh, A.
Potential Analysis of Defossilized Operation of a Heavy-Duty Dual-Fuel Engine Utilizing Dimethyl Carbonate/Methyl Formate as Primary and Poly Oxymethylene Dimethyl Ether as Pilot Fuel03-17-07-005304/18/2024
This study demonstrates the defossilized operation of a heavy-duty port-fuel-injected dual-fuel engine and highlights its potential benefits with minimal retrofitting effort. The investigation focuses on the optical characterization of the in-cylinder processes, ranging from mixture formation, ignition, and combustion, on a fully optically accessible single-cylinder research engine. The article revisits selected operating conditions in a thermodynamic configuration combined with Fourier transform infrared spectroscopy. One approach is to quickly diminish fossil fuel use by retrofitting present engines with decarbonized or defossilized alternatives. As both fuels are oxygenated, a considerable change in the overall ignition limits, air–fuel equivalence ratio, burning rate, and resistance against undesired pre-ignition or knocking is expected, with dire need of characterization. Two simultaneous high-speed recording channels granted cycle-resolved access to the natural flame luminosity
Mühlthaler, Markus Sebastian, Härtl, Martin, Jaensch, Malte
Study of Dimethyl Ether Fuel Spray Characteristics and Injection Profile2024-01-270204/09/2024
The majority of transportation systems have continued to be powered by the internal combustion engine and fossil fuels. Heavy-duty applications especially are reliant on diesel engines for their high brake efficiency, power density, and robustness. Although engineering developments have advanced engines towards significantly fewer emissions and higher efficiency, the use of fossil-derived diesel as fuel sets a fundamental threshold in the achievable total net carbon reduction. Dimethyl ether can be produced from various renewable feedstocks and has a high chemical reactivity making it suitable for heavy-duty applications, namely compression ignition direct injection engines. Literature shows the successful use of DME fuels in diesel engines without significant hardware modifications. The lower energy density of DME calls for adjustments in injection parameters (such as injection pressure and duration) or modifications to the injector geometry to align with the energy levels found in
Cong, Binghao, Leblanc, Simon, Yu, Xiao, Zheng, Ming
Experimental Investigation of Internal and External EGR Effects on a CNG-OME Dual-Fuel Engine2024-01-236104/09/2024
Dual-fuel engines powered by renewable fuels provide a potential solution for reducing the carbon footprint and emissions of transportation, contributing to the goal of achieving sustainable mobility. The investigation presented in the following uses a dual-fuel engine concept running on biogas (referred to as CNG in this paper) and the e-fuel polyoxymethylene dimethyl ether (OME). The current study focuses on the effects of exhaust gas rebreathing and external exhaust gas recirculation (EGR) on emissions and brake thermal efficiency (BTE). A four-cylinder heavy-duty engine converted to dual-fuel operation was used to conduct the engine tests at a load point of 1600 min-1 and 9.8 bar brake mean effective pressure (BMEP). The respective shares of high reactivity fuel (HRF, here: OME) and low reactivity fuel (LRF, here: CNG) were varied, as were the external and internal EGR rates and their combinations. CNG was injected into the intake manifold to create a homogeneous air-fuel mixture
Jost, Ann-Kathrin, Guenthner, Michael, Weigel, Alexander
Light Duty Engine Performance Characteristics with Dimethyl Ether and Propane2024-01-212604/09/2024
The paper explores the performance characteristics of a compression ignition HYUNDAI 2.2L engine operating with Dimethyl Ether (DME). Test are carried out at three operating conditions that weigh heavily in the FTP75 certification cycle (1000rpm-12Nm, 1500rpm-50Nm, 2000rpm-100Nm). The engine features a high-pressure common rail fuel injection system designed to operate with liquified gases. The main component of the fuel system is a high-pressure pump that incorporates an electronic inlet metering valve commanded on a crank-angle base to control the rail pressure. The pump, which requires no pressure regulator, provides the flow needed to the injectors without flow returning to the inlet. This novel fueling system is leveraged in tests that are conducted to examine the impact of EGR, combustion phasing, injection pressure on efficiency and emissions. In addition, the impact of introducing 15% Propane by mass is examined. During the tests, the engine ECU is aided by an Engine Controller
De Ojeda, William, Wu, Simon (Haibao), Ankobea-Ansah, King, Hassan, Hafiz Ahmad, Hall, Carrie
Oxygenated Fuels as Reductants for Lean NOx Trap Regeneration2024-01-213204/09/2024
The push for environmental protection and sustainability has led to strict emission regulations for automotive manufacturers as evident in EURO VII and 2026 EPA requirements. The challenge lies in maintaining fuel efficiency and simultaneously reducing the carbon footprint while meeting future emission regulations. Alcohol (primarily methanol, ethanol, and butanol) and ether (dimethyl ether) fuels, owing to their comparable energy density to existing fuels, the comparative ease of handling, renewable production, and suitable emission characteristics may present an attractive drop-in replacement, fully or in part as an additive, to the gasoline/diesel fuels, without extensive modifications to the engine geometry. Additionally, lean and diluted combustion are well-researched pathways for efficiency improvement and reduction of engine-out emissions of modern engines. Modern internal combustion engines typically employ various in-cylinder emission reduction techniques along with a multi
Sandhu, Navjot Singh, Yu, Xiao, Ting, David, Zheng, Ming
Effect of Spark Assisted Compression Ignition on the End-Gas Autoignition with DME-air Mixtures in a Rapid Compression Machine2024-01-282204/09/2024
Substantial effort has been devoted to utilizing homogeneous charge compression ignition (HCCI) to improve thermal efficiency and reduce emission pollutants in internal combustion engines. However, the uncertainty of ignition timing and limited operational range restrict further adoption for the industry. Using the spark-assisted compression ignition (SACI) technique has the advantage of using a spark event to control the combustion process. This study employs a rapid compression machine to characterize the ignition and combustion process of Dimethyl ether (DME) under engine-like background temperature and pressures and combustion regimes, including HCCI, SACI, and knocking onsite. The spark ignition timing was swept to ignite the mixture under various thermodynamic conditions. This investigation demonstrates the presence of four distinct combustion regimes, including detonation, strong end-gas autoignition, mild end-gas autoignition, and HCCI. The observation indicates that HCCI
Jin, Long, Yu, Xiao, Wang, Meiping, Reader, Graham, Zheng, Ming
Investigation of Fuel Injection Pressure Impact on Dimethyl Ether Combustion2023-01-164410/31/2023
Compression ignition engines used in heavy-duty applications are typically powered by diesel fuel. The high energy density and feedstock abundance provide a continuing source for the immense energy demand. However, the heavy-duty transportation sector is challenged with lowering greenhouse gas and combustion by-product emissions, including carbon dioxide, nitrogen oxides, and particulate matter. The continuing development of engine management and combustion strategies has proven the ability to meet current regulations, particularly with higher fuel injection pressure. Nonetheless, a transition from diesel to a renewable alternative fuel source will play a significant role in reducing greenhouse gases while maintaining the convenience and energy density inherent in liquid fuels. Dimethyl ether is a versatile fuel that possesses combustion properties suitable for compression ignition engines and physical properties helpful for clean combustion. The higher volatility of DME may permit
Leblanc, Simon, Wang, Linyan, Sandhu, Navjot Singh, Yu, Xiao, Zheng, Ming
Characterization of an Integrated Three-Way Catalyst/Lean NOx Trap System for Lean Burn SI Engines2023-01-165810/31/2023
The push for environmental protection and sustainability has led to strict emission regulations for automotive manufacturers as evident in EURO VII and 2026 EPA requirements. The challenge lies in maintaining fuel efficiency and simultaneously reducing the carbon footprint while meeting future emission regulations. Alcohol (primarily methanol, ethanol, and butanol) and ether (dimethyl ether) fuels, owing to their comparable energy density to existing fuels, the comparative ease of handling, renewable production, and suitable emission characteristics may present an attractive drop-in replacement, fully or in part as an additive, to the gasoline/diesel fuels, without extensive modifications to the engine geometry. Additionally, lean and diluted combustion are well-researched pathways for efficiency improvement and reduction of engine-out emissions of modern engines. Modern spark ignition (SI) engines typically employ various in-cylinder emission reduction techniques along with a three
Sandhu, Navjot Singh, Leblanc, Simon, Yu, Xiao, Reader, Graham, Zheng, Ming
A Novel Approach to Constructing Reactivity-Based Simplified Combustion Model for Dual Fuel Engine2023-01-162710/31/2023
To achieve higher efficiencies and lower emissions, dual-fuel strategies have arisen as advanced engine technologies. In order to fully utilize engine fuels, understanding the combustion chemistry is urgently required. However, due to computation limitations, detailed kinetic models cannot be used in numerical engine simulations. As an alternative, approaches for developing reduced reaction mechanisms have been proposed. Nevertheless, existing simplified methods neglecting the real engine combustion processes, which is the ultimate goal of reduced mechanism. In this study, we propose a novel simplified approach based on fuel reactivity. The high-reactivity fuel undergoes pyrolysis first, followed by the pyrolysis and oxidation of the low-reactivity fuel. Therefore, the simplified mechanism consists of highly lumped reactions of high-reactivity fuel, radical reactions of low-reactivity fuel and C0-C2 core mechanisms. We have applied this methodology to a dual-fuel engine fueled with
Li, Ang, Zhang, Zhenyingnan, Li, Zhuohang, Zhu, Lei, Huang, Zhen
Effects of Hydrocarbon with Different Ignition Properties and Hydrogen Blended Fuels on Autoignition and Combustion in an IC Engine2023-01-180210/24/2023
Hydrogen has attracted attention as one of the key fuels for making internal combustion engines carbon neutral. However, the combustion characteristics of hydrogen differ greatly from those of conventionally used hydrocarbons. Therefore, in order to develop next-generation internal combustion engines that operate on hydrogen, it is first necessary to have a thorough understanding of the combustion characteristics of hydrogen. Engines that can take maximum advantage of those characteristics should be developed on the basis of that knowledge. Toward that end, the purpose of this study was to investigate the fundamental combustion characteristics of hydrogen in a test engine. This paper presents the results of an investigation of the effects on low-temperature oxidation reactions and autoignition when hydrogen was blended into dimethyl ether (DME) [1, 2], a gaseous hydrocarbon fuel. Combustion experiments were conducted using a single-cylinder engine, and chemical kinetic simulations were
Kuwabara, Kenta, MANABE, YUSUKE, Mito, Shinji, YAMAGIWA, REO, Yamaguchi, Takahiro, Yoshihara, Shintaro, MIYAMOTO, Sekai, Iijima, Akira
Investigation of Dimethyl Ether Dual-Fuel Combustion Using Propane and Ethanol as Premixed Fuel2023-32-001809/29/2023
The combustion and emission characteristics of dual-fuel combustion were investigated using dimethyl ether direct injection and premixed low-carbon fuels. Dimethyl ether was used as the direct injection fuel for its high reactivity and low propensity to form particulate matter. Ethanol and Propane, two fuels of low reactivity, were premixed in the intake port. An injection timing sweep of varying premixed energy shares and engine loads was tested. Combustion analysis was conducted based on in-cylinder pressure measurements while detailed speciation of engine-out emissions was performed via FTIR. The proper injection advance and premixed energy share can realize low NOx and high combustion efficiency. Ethanol showed stronger impact to DME ignition delay as compared with propane.
LeBlanc, Simon, Wang, Linyan, Yu, Xiao, Zheng, Ming
A Study of Autoignition and Combustion Characteristics in an HCCI Engine using a Blended Fuel of DME and City Gas2023-32-001709/29/2023
In recent years, there has been a need to reduce CO2 emissions from internal combustion engines in order to achieve an energy-saving and low-carbon society. Against this backdrop, the authors have focused attention on Homogeneous Charge Compression Ignition (HCCI) combustion that achieves both high efficiency and clean emissions. With HCCI combustion, a premixed mixture of fuel and air is supplied to the cylinder and autoignited by piston compression to drive the engine. Autoignition makes it possible to operate the engine at a high compression ratio, enabling the HCCI combustion system to attain high efficiency. However, HCCI combustion also has some major unresolved issues. Two principal issues that can be cited are ignition timing control for igniting the mixture at the proper time and assurance of suitable combustion conditions following ignition to prevent incomplete combustion and knocking. The combustion characteristics of a blended fuel of dimethyl ether (DME) as the ignition
Yamagiwa, Reo, MANABE, Yusuke, MITO, Shinji, IIJIMA, Akira, YOSHIHARA, Shintaro, YAMAGUCHI, Takahiro, MIYAMOTO, Sekai
Study on Combustion and Exhaust Emissions Characteristics of Oxymethylene Dimethyl Ether Blends with Fischer-Tropsch Fuels in Diesel Engines2023-32-016709/29/2023
Synthetic fuels (e-fuels) synthesized from H2 and CO by renewable electricity are expected as the next- generation diesel fuels and two types of e-fuels have received extensive attention: Fischer-Tropsch (FT) fuel and Oxymethylene dimethyl ether (OME). In this study the effects of OME blending ratios with 0 to 50 vol.% in FT fuels on combustion, emissions and spray characteristics in diesel engines are investigated. The results suggest that the OME blends to FT fuels suppressed the deterioration in combustion efficiency under low intake oxygen concentration conditions. The smoke emissions of FT fuels and OME blended fuels were both lower than those of diesel fuel and decreased with the increase in the OME blend ratio, and the soot-NOx trade-off relation in diesel engines can be improved.
Yuan, Haoyu, Tsukuda, Takuma, Nishino, Jumpei, Shibata, Gen, Ogawa, Hideyuki
The Effect of Methane Addition on the Low-Temperature Oxidation Preparation and the Thermal Ignition Preparation of Dimethyl Ether Under Representative Engine In-Cylinder Thermal Conditions2023-32-015009/29/2023
Dimethyl ether (DME) is a highly reactive diesel substitute that can be used as a pilot fuel to ignite low- reactivity methane (CH4) in heavy-duty engines. To optimize the efficiency and emissions of CH4/DME dual-fuel engines, it is crucial to study the fundamental combustion characteristics of DME mixed with methane. This study focuses on the influence of CH4 addition on the low-temperature oxidation (LTO) preparation stage and the thermal ignition (TI) preparation stage of DME in the two-stage ignition process, as these two stages respectively control the ignition delay of the first and second stages. The comparison is made between pure DME and a 50% CH4 and 50% DME blended fuel, operating under thermodynamic conditions representing the engine in- cylinder environment at 30 atm pressure, 650K temperature, and a stoichiometric equivalence ratio. The results show that the addition of methane hardly affects the control mechanism of the two-stage ignition of DME. Specifically, the LTO
Ou, Juan, Yang, Ruomiao, Yan, Yuchao, Liu, Zhentao, Liu, Jinlong
Insights into combustion and performance of HCCI engine fed with PODE 1 and H 2 -rich PODE 1 -reformate2023-32-000409/29/2023
A transition to sustainable energy sources, carbon- free/neutral energy carriers and efficient combustion technologies is intensively discussed as a key pathway in achieving a greener, more secure energy future. In particular, enhancement of internal combustion engine (ICE) performance using promising alternative carbon- neutral propellants, waste heat recovery (WHR) and state-of-the-art combustion methods has gained high research attention. Polyoxymethylene dimethyl ethers (PODEn, OMEn), well-suited for compression-ignition (CI) combustion, arouse strong interest as potentially sustainable and cleaner alternatives to diesel fuel. This study reports for the first-time numerically examined combustion performance characteristics of reforming- controlled compression ignition (RefCCI) ICE engine, managed by mixing of polyoxymethylene dimethyl ether 1 (PODE1) and its hydrogen-rich reforming products (PODE1-reformate) obtained through thermo- chemical recuperation. The results showed that
Buntin, Denis, Tartakovsky, Leonid
Electrofuel Concept of Diesel and Oxygenate Fuels Reduces Engine-Out Emissions2023-24-009008/28/2023
Electrofuels produced from renewable hydrogen (H2) and captured carbon dioxide (CO2) can be sustainable and carbon-neutral. Paraffinic electrodiesel (e-diesel) can be produced via Fischer-Tropsch synthesis with fuel properties resembling hydrotreated vegetable oils. Electrofuels can be also oxygenated compounds, such as oxymethylene dimethyl ethers (OMEn), having different chain lengths. We studied emissions using paraffinic diesel mimicking e-diesel and its blend with 10% of OME3-5, which has diesel-type fuel properties, in comparison with normal EN590 diesel fuel. An intensive measurement campaign was performed with a modern diesel engine without exhaust aftertreatment to study the effect of fuel on the engine-out emissions. Measurements with the RMC-C1 cycle included detailed characterization of gaseous, particle and polyaromatic hydrocarbon (PAH) emissions having adverse effects on health and the environment. In these tests without a diesel particulate filter, the fuel containing
Aakko-Saksa, Paivi, Järvinen, Anssi, Karppanen, Mikko, Koponen, Paivi, Piimäkorpi, Pekka, Lehtonen, Juha, Harni, Sami, Aurela, Minna, Timonen, Hilkka, Marjanen, Petteri, Markkula, Lassi, Rönkkö, Topi, Hoivala, Jussi
Active Plasma Probing for Lean Burn Flame Detection2023-01-029304/11/2023
Combustion diagnostics of highly diluted mixtures are essential for the estimation of the combustion quality, and control of combustion timing in advanced combustion systems. In this paper, a novel fast response flame detection technique based on active plasma is introduced and investigated. Different from the conventional ion current sensing used in internal combustion engines, a separate electrode gap is used in the detecting probing. Further, the detecting voltage across the electrode gap is modulated actively using a multi-coil system to be slightly below the breakdown threshold before flame arrival. Once the flame front arrives at the probe, the ions on the flame front tend to decrease the breakdown voltage threshold and trigger a breakdown event. Simultaneous electrical and optical measurements are employed to investigate the flame detecting efficacy via active plasma probing under both quiescent and flow conditions. The RT-FPGA system provides flexible, prompt, and precise
Wang, Linyan, Yu, Xiao, Cong, Binghao, Li, Liguang, Chen, Guangyun, Zheng, Ming
Performance and Emission Characteristics of Direct Injection DME Combustion under Low NOx Emissions2023-01-032704/11/2023
Compression ignition internal combustion engines provide unmatched power density levels, making them suitable for numerous applications including heavy-duty freight trucks, marine shipping, and off-road construction vehicles. Fossil-derived diesel fuel has dominated the energy source for CI engines over the last century. To mitigate the dependency on fossil fuels and lessen anthropogenic carbon released into the atmosphere within the transportation sector, it is critical to establish a fuel source which is produced from renewable energy sources, all the while matching the high-power density demands of various applications. Dimethyl ether (DME) has been used in non-combustion applications for several decades and is an attractive fuel for CI engines because of its high reactivity, superior volatility to diesel, and low soot tendency. A range of feedstock sources can produce DME via the catalysis of syngas. In this work, DME is applied in a direct injection compression ignition combustion
Leblanc, Simon, M, Murugesa Pandian, Han, Xiaoye, Tjong, Jimi, Zheng, Ming
Ignition and Combustion Characteristics of OME 3-5 and N-Dodecane: A Comparison Based on CFD Engine Simulations and Optical Experiments2023-01-030504/11/2023
Synthetic fuels derived from renewable power sources, so-called e-fuels, will play a crucial role in achieving climate-neutral future mobility because they can be used in the existing fleets and in hard-to-decarbonize applications. In particular e-fuels that contain oxygen in their chemical structure can also burn more cleanly in terms of soot formation. For compression-ignition engines, polyoxymethylene dimethyl ethers (PODEs or OMEs) are among the most promising candidates for such oxygenated e-fuels. Here, we investigated the characteristics of injection and combustion of OME3-5 mixture compared to n-dodecane, a reference diesel-like fuel. Both single and multi-injection, comprising a short pilot injection, is used. Experiments were performed in a single-cylinder optically accessible Bowditch-type engine, injecting with 1500 bar pressure with a 3-hole injector (Spray B of the Engine Combustion Network). Liquid and vapor penetration were measured by imaging the spray illuminated by a
Wiesmann, Frederik, Bauer, Esra, Kaiser, Sebastian A., Lauer, Thomas
DME-Propane Ignition Delay Time Measurements at Mixing Controlled Compression Ignition Engine-Relevant Conditions2023-01-033004/11/2023
The blend of dimethyl ether (DME, CH3OCH3) and propane (C3H8) is a potentially renewable fuel mixture that has the potential to replace diesel in compression ignition engines. The combination can potentially reduce particulate and greenhouse gas emissions compared to a conventional diesel engine operating under similar conditions. However, detailed conceptual and simulation studies must be conducted before adopting a new fuel on a compression ignition engine. For these simulations, accurate chemical kinetic models are necessary. However, the validity of chemical kinetic mechanisms in the literature is unknown for mixing controlled compression ignition (MCCI) engine operating conditions. Hence, in this work, we studied the ignition of dimethyl ether (DME) and propane blends in a shock tube at MCCI engine conditions. Ignition delay time (IDT) data was collected behind the reflected shock for DME-propane mixtures for heavy-duty compression ignition (CI) engine parameters. Undiluted
Mohammed, Zuhayr Pasha, Khaleel Rahman, Ramees, Pierro, Michael, Urso, Justin, Vasu, Subith
CFD Modeling of a DME CI Engine in Late-PCCI Operating Conditions2023-01-020304/11/2023
Predictive combustion models are useful tools towards the development of clean and efficient engines operating with alternative fuels. This work intends to validate two different combustion models on compression-ignition engines fueled with Dimethyl Ether. Both approaches give a detailed characterization of the combustion kinetics, but they substantially differ in how the interaction between fluid-dynamics and chemistry is treated. The first one is single-flamelet Representative Interactive Flamelet, which considers turbulence-kinetic interaction but cannot correctly describe the stabilization of the flame. The second, named Tabulated Well Mixed, correctly accounts for local flow and mixture conditions but does not consider interaction between turbulence and chemistry. An experimental campaign was carried out on a heavy-duty truck engine running on DME at a constant load considering trade-off of EGR and SOI. Simulations results of 10 operating conditions show that both models can be
Schirru, Andrea, Hardy, Gilles, Wright, Yuri M., Lucchini, Tommaso, D'Errico, Gianluca, Soltic, Patrik, Hilfiker, Thomas
Prediction of Spray Vapor Tip Penetration of Diesel, Biodiesel and Synthetic Fuels Using Artificial Neural Networks with Confidence Intervals2023-01-031504/11/2023
Fuel spray and atomization processes affect the combustion and emissions characteristics of fuels in internal combustion engines. Biodiesel and synthetic fuels such as oxymethylene dimethyl ethers (OME) show great promise as alternative fuels and are complementary in terms of reproducing the fluid properties of conventional diesel fuels through blending, for instance. Averaged experimental results, empirical correlations and Computational Fluid Dynamics (CFD) have typically been used to evaluate and predict fuel spray liquid and vapor penetration values so as to better design internal combustion engines. Lately, Machine Learning (ML) is being applied to these investigations. Typically, ML spray studies use averaged experimental data and then over-trained neural networks on the limited available data. By contrast, in this study we present spray vapor tip penetration predictions using artificial neural networks with systematic treatment of uncertainties arising from experimental
Richards, Bryn, Emekwuru, Nwabueze
Extension and Validation of a Constant Equivalence Ratio Multi-Zone Approach to DME Combustion in Vessels and CI Engines2023-01-019304/11/2023
This work has the objective to present the extension of a novel quasi-dimensional model, developed to simulate the combustion process in diesel Compression Ignition (CI) engines, to describe this process when Dimethyl ether (DME) is used as fuel. DME is a promising fuel in heavy-duty CI engines application thanks to its high Cetane Number (CN), volatility, high reactivity, almost smokeless combustion, lower CO2 emission and the possibility to be produced with renewable energy sources. In this paper, a brief description of the thermodynamic model will be presented, with particular attention to the implementation of the Tabulated Kinetic Ignition (TKI) model, and how the various models interact to simulate the combustion process. The model has been validated against experimental data derived from constant-volume DME combustion, in this case the most important parameters analyzed and compared were the Ignition Delay (ID) and Flame Lift Off Length (FLOL). Following this first validation
Ballerini, Alberto, D'Errico, Gianluca, Onorati, Angelo, Tamborski, Matteo
Development of a High-Pressure Fuel Injection System for Use with Propane-DME2023-01-040304/11/2023
Paper details the design approach and performance of a high-pressure common rail fuel injection system used with Propane-DME mixtures targeting high injection pressures on a light duty 2.2L inline-4 compression ignition engine. The study estimates the bulk modulus of elasticity based on the hardware geometry and operating pressures to assess the compressibility of Propane and DME across a range of pressures typical of the LD engine application. The compressibility factor ranges from 500 to 3000 bar, significantly lower than the theoretical values for the conditions tested. The high-pressure pump performance is optimized via the implementation of an inlet metering valve operated on a crank-angle open/close sequence to control pressure at the common rail. The application of a model-based controller and the use of high-speed sampling of rail pressure indicate that pressure at the rail can be attained with the pump metering valve, and without use of the pressure relieve valve present in
De Ojeda, William, Wu, Simon (Haibao)
PRODUCT BRIEFS23TOFHP04_1604/01/2023
Strategies for Reduced Engine-Out HC, CO, and NOx Emissions in Diesel-Natural Gas and POMDME-Natural Gas Dual-Fuel Engine2022-01-046003/29/2022
Dual-fuel engines employ precisely metered amounts of a high reactivity fuel (HRF) such as diesel at high injection pressures to burn a low reactivity fuel (LRF) such as natural gas, which is typically fumigated into the intake manifold. Dual fuel engines have demonstrated the ability to achieve extremely low engine-out oxides of nitrogen (NOx) emissions compared to conventional diesel combustion at the expense of unburned hydrocarbon (HC) and carbon monoxide (CO) emissions. At low engine loads, due to low in-cylinder temperatures, oxidation of HC and CO is very challenging. This results in both compromised combustion and fuel conversion efficiencies. The experimental campaign discussed in this paper involved a set of six engine control parameters that were strategically varied to find the best possible efficiency-emissions trade-offs for both diesel- and poly-oxy methylene dimethyl ether (POMDME)-natural gas dual fuel combustion on the University of Alabama single-cylinder research
Hariharan, Deivanayagam, Partridge, Kendyl, Narayanan, Abhinandhan, Srinivasan, Kalyan, Krishnan, Sundar Rajan, Anandaraman, Nandagopalan
Combustion Characterization of DME-Fueled Dual Fuel Combustion with Premixed Ethanol2022-01-046103/29/2022
The heterogeneous nature of direct injection (DI) combustion yields high combustion efficiencies but harmful emissions through the formation of high nitrogen oxide (NOx) and smoke emissions. In response, extensive empirical and computational research has focused on balancing the NOx-smoke trade-off to limit diesel DI combustion emissions. Dimethyl ether (DME) fuel is applicable in DI compression ignition engines and its high fuel oxygen produces near-smoke-free emissions. Moreover, the addition of a premixed fuel can improve mixture homogeneity and minimize the DI fuel energy demands lessening injection durations. For this technique, a low reactivity fuel such as ethanol is essential to avoid early autoignition in high compression ratio engines. In this work, empirical experiments of dual fuel operation have been conducted using premixed ethanol with high-pressure direct injection DME. The engine performance was characterized with DI diesel fuel as a baseline, and the matching
Leblanc, Simon, Jin, Long, Sandhu, Navjot S., Yu, Xiao, Zheng, Ming
An Investigation of OME 3 -Diesel Fuel Blend on a Multi-Cylinder Compression Ignition Engine2022-01-043903/29/2022
Oxygenated, low energy-density fuels have the potential to decouple the NOx-soot emissions trade-off in compression-ignition engines. Additionally, synthetic fuels can provide a pathway to reach carbon-neutral utilization of hydrocarbon-based fuels in IC engines. Oxymethylene Dimethyl Ether (OME) is one such synthetic, low energy-density fuel, derived from sustainable sources that in combination with conventional fossil fuels with higher energy content, has the potential to reduce CO2 emissions below the US and EU VI legislative limits, while maintaining ultra-low soot emissions. The objective of this work is to investigate and compare the performance, emissions and efficiency of a modern multi-cylinder diesel engine under conventional high temperature combustion (HTC) with two different fuels; 1) OME310 - a blend of 10% OME3 by volume, with conventional Ultra-Low Sulphur Diesel (ULSD), and 2) D100 - conventional ULSD in North America. EGR sweep tests at three speed-load points (with
Asad, Usman, Ramos, Manuel, Tjong, Jimi
A Study of Combustion Inefficiencies in SI Engines Powered by Alcohol and Ether Fuels Using Detailed Emission Speciation2022-01-052003/29/2022
Advanced combustion engines, as power sources, dominate all aspects of the transportation sector. Stringent emission and fuel efficiency standards have promoted the research interest in advanced combustion strategies and alternative fuels. Owing to the comparable energy density to the existing fossil fuels and renewable production, alcohol and ether fuels may be a suitable replacement, or an additive to the gasoline/diesel fuels to meet the future emission standards with minimal modification to current engine geometry. Furthermore, lean and diluted combustion are well-researched pathways for efficiency improvement and reduction of engine-out emissions of modern engines. However, lean-burn or EGR dilution can introduce combustion inefficiencies in the form of excessive hydrocarbon, carbonyl species and carbon monoxide emissions. In this study, the total energy loss to the exhaust in the form of emission species due to incomplete/inefficient combustion of alcohol (butanol and ethanol
Sandhu, Navjot Singh, Leblanc, Simon, Yu, Xiao, Reader, Graham, Ting, David, Zheng, Ming
Laminar Flame Speed Measurements of Propane/Dimethyl-Ether/Air Mixtures2022-01-051003/29/2022
An experimental study on the laminar flame speeds (LFS) of premixed propane/dimethyl-ether (DME)/air flames was conducted inside a constant-volume chamber at UCF. Mixtures of propane and DME were selected for this study as they show promise as a fuel source that can be utilized in the automotive diesel industry as a low emission alternative fuel. The LFS of a fuel mixture is a crucial characteristic of combustion for its application in the design process of engines, as it can be used as a metric for fuel performance. Further underscoring the importance of gathering LFS data for these mixtures is its use in validating chemical kinetic mechanisms that can be utilized for further research in the field. LFS is dependent on fuel/oxidant mixture temperature, pressure, and equivalence ratio. While some studies exist examining other characteristics of combustion regarding propane/DME fuel mixtures, there is minimal information on the laminar flame speed of the mixtures. This study tested
Vasu, Subith, Weiner, Joshua, Kim, Gihun, Ghorpade, Ritesh
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