Browse Topic: Exhaust systems

Items (6,568)
Reducing pollutant emissions remains a major challenge for the automotive industry, driven by increasingly stringent environmental regulations. While solutions such as electric vehicles (EVs) and hybrid electric vehicles (HEVs) have been developed, internal combustion engines (ICEs) continue to dominate many markets, requiring additional emission control strategies. Traditional technologies like catalytic converters and advanced injection systems primarily optimize performance once the engine reaches its operating temperature. However, during the cold start phase, when engine temperatures are below optimal, combustion efficiency drops, resulting in increased emissions of non-methane organic gases (NMOG) and nitrogen oxides (NOx). This phase is further compromised by factors such as fuel droplet size and suboptimal catalyst performance. In response, this work presents the development of a Hardware-in-the-Loop (HiL) platform to study the impact of heated injection technology on cold
Triviño, Juan David ParraTeixeira, Evandro Leonardo SilvaDe Lisboa, Fábio CordeiroAguilar, Raul Fernando SánchezOliveira, Alessandro Borges De Sousa
This study develops deep learning (DL) long–short-term memory (LSTM) models to predict tailpipe nitrogen oxides (NOx) emissions using real-driving on-road data from a heavy-duty Class 8 truck. The dataset comprises over 4 million data points collected across 11,000 km of driving under diverse road, weather, and load conditions. The effects of dataset size, model complexity, and input feature set on model performance are investigated, with the largest training dataset containing around 3.5 million data points and the most complex model consisting of over 0.5 million parameters. Results show that a large and diverse training dataset is essential for achieving accurate prediction of both instantaneous and cumulative NOx emissions. Increasing model complexity only enhances model performance to a certain extent, depending on the size of the training dataset. The best-performing model developed in this study achieves an R2 higher than 0.9 for instantaneous NOx emissions and less than a 2
Shahpouri, SaeidJiang, LuoKoch, Charles RobertShahbakhti, Mahdi
Komatsu has launched a new excavator, the PC220LCi-12, that features its latest intelligent machine control technology. IMC 3.0 incorporates automation enhancements and a reported “construction-industry first” technology - factory-integrated 3D boundary control - designed to boost operator productivity. The intelligent machine, displayed previously at Bauma 2025 in Munich, Germany, has many of the same features as the new PC220LC-12 excavator, including a cab that is 28% larger, with 30% more legroom and 50% improved visibility compared to the PC210LC-11 model. Other advantages the new machines offer are up to a 20% increase in fuel efficiency thanks to a new electrohydraulic system and 129-kW (173-hp) next-generation engine, and up to a 20% reduction in maintenance costs due to longer replacement intervals for hydraulic oil and oil filters and longer cleaning intervals for the particulate filter.
Gehm, Ryan
As a zero-carbon fuel, ammonia has the potential to completely defossilize combustion engines. Due to the inert nitrogen present in the molecule, ammonia is difficult to ignite or burn. Even if the ammonia can be successfully ignited, combustion will be very slow and there is a risk of flame quenching, i.e. the flame going out before the ammonia-air mixture has been almost completely converted. Both the difficult flammability and the slow combustion result in high ammonia slip, which should be avoided at all costs. The engine efficiency is also greatly reduced. Safe ignition and burn-through can be achieved by drastically increasing the ignition energy and/or using a reaction accelerator such as hydrogen. The planned paper will use detailed 1D and 3D CFD calculations to show how high the potential of ammonia combustion in an internal combustion engine is when an active pre-chamber is used as the ignition system. As a result of the flame jets penetrating into the main combustion chamber
Sens, Marcvon Roemer, LorenzRieß, MichaelFandakov, AlexanderCasal Kulzer, Andre
The engine has played a pivotal role in controlling regulated pollutants at the in-cylinder combustion level through strategies such as Direct Injection, Common Rail Systems, and Exhaust Gas Recirculation up to Bharat (CEV/Trem) Stage-III. With the advent of more stringent emission norms, specifically Bharat (CEV/Trem) Stage-IV and V, the importance of Exhaust After-Treatment Systems (EATS) in managing emissions outside the engine has significantly increased. The inclusion of Particulate Number (PN) limits in Bharat (CEV/Trem) Stage-V necessitates the use of Diesel Particulate Filters (DPF), which trap soot particles that must be periodically removed through a process known as regeneration. Regeneration requires elevated exhaust temperatures, typically achieved via exothermic reactions in the Diesel Oxidation Catalyst (DOC), facilitated by diesel fuel addition through external injection or in-cylinder injection strategies. This study investigates both external and in-cylinder injection
Bandaru, BalajiM, BalasubramanianV, ShunmugaG, Senthil KumarMahesh, P
The key performance evaluation criteria for any automotive exhaust system are pass-by noise (PBN), exhaust backpressure, durability and reliability, exhaust brake performance, aesthetics (if visible from outside the chassis), cost, weight and safety. Also, with changes in emission norms, emission from Exhaust Aftertreatment Systems (EATS) is one of the crucial parameters while designing the exhaust system. This paper covers a critical problem faced during the Beta Proto Build and Testing phase of exhaust tail pipe assembly. The exhaust tail pipe assembly had loose fitting issues, which can cause problems during the functioning of the truck. Parameters like material of the pipe, length of strap, tightening torque and tolerance of the pipe diameter were considered to resolve the fitment issue. The resolution is done with the help of Design of Experiments (DoE) and Pugh Matrix Analysis based on QDCFSS (Quality, Design, Cost, Feature, Safety and Sustainability). Design for Assembly (DFA
P, Balu MukeshRokade, AdityaBiswas, Sanjoy
Off-highway vehicles (OHVs) in sectors such as mining, construction, and agriculture contribute significantly to global greenhouse gas (GHG) emissions, particularly carbon dioxide (CO₂) and nitrogen oxides (NOₓ). Despite the growth of alternative fuels and electrification, diesel engines remain dominant due to their superior torque, reliability, and adaptability in harsh environments. This paper introduces a novel onboard exhaust capture and carbon sequestration system tailored for diesel-powered OHVs. The system integrates nano-porous filters, solid-state CO₂ adsorbents, and a modular storage unit to selectively capture CO₂ and NOₓ from exhaust gases in real time. Captured CO₂ is then compressed for onboard storage and potential downstream utilization—such as fuel synthesis, carbonation processes, or industrial sequestration. Key innovations include: A dual-function capture mechanism targeting both CO₂ and NOₓ Lightweight thermal-regenerative adsorption materials Integration with
Vashisht, Shruti
In the power industry, high-power Diesel Generator (DG) sets often utilize high power V-engine cylinder configurations to enhance power output within a compact design, ensuring smoother operation and reduced vibration. In this V-engine configurations, the exhaust gas mass flow rate is significantly higher compared to inline engines of similar displacement, due to the greater number of cylinders operating in a compact space, which leads to a higher volume of exhaust gases expelled in a shorter duration. This necessitates the use of a dual Exhaust After Treatment System (EATS) to effectively manage NOx emissions. High-power gensets typically emit NOx levels around 9 g/kWh, presenting significant challenges for developers in adhering to stringent emission standards. To address these challenges and meet CPCB IV+ emission norms, we propose a dual urea dosing system integrated with a novel control strategy aimed at optimizing the treatment of exhaust gases. This paper introduces a dual
K, SabareeswaranK K, Uthira Ramya BalaS K, NejanthenA, RavikumarS, Mahendra BoopathiYS, Ananthkumar
The Dosing Control Unit (DCU) is a vital component of modern emission control systems, particularly in diesel engines employing Selective Catalytic Reduction technology (SCR). Its primary function is to accurately control the injection of urea or Diesel Exhaust Fluid (DEF) into the exhaust stream to reduce nitrogen oxide (NOₓ) emissions. This paper presents the architecture, operation, diagnostic features, and innovation of a newly developed DCU system. The Engine Control Unit, using real-time data from sensors monitoring parameters such as exhaust temperature, NOₓ levels, and engine load, calculates the required DEF dosage. Based on DEF dosing request, the DCU activates the AdBlue pump and air valve to deliver the precise quantity of diesel exhaust fluid needed under varying engine conditions. The proposed system adopts a master-slave configuration, with the ECU as the master and the DCU as the slave. The controller design emphasizes cost-effectiveness and simplified hardware, and
Raju, ManikandanK, SabareeswaranK K, Uthira Ramya BalaKrishnakumar, PalanichamyArumugam, ArunkumarYS, Ananthkumar
The current and upcoming Internal Combustion Engine (ICE) emission norms are very stringent. It is difficult to meet emission standards with just combustion optimization techniques. As a result, post-treatment is required for Engine-out emissions. Otherwise, these hazardous gases impact the ecosystem of living beings. Many technologies are implemented at the exhaust for reducing the emissions. Diesel Particulate Filter (DPF) is one such technique to achieve lower Particulate Matter (PM) and Particulate Number (PN) emission goals. In order to achieve such emission reduction, the DPF undergoes periodic cleaning called regeneration. During regeneration, the exhaust systems including DPF are maintained at elevated temperatures to achieve proper cleaning. When the vehicle is in regeneration, sudden braking or accelerator pedal release leads to engine Drop to Idle speeds (DTI), which sharply increases the temperature gradient inside the DPF which may result in physical damage like cracks
Anandakrishnan, AbhishekA L, PrathimaBenni Matada, Ajay
Two-stroke engines represent an attractive solution for aviation industry applications (UAVs, VTOL aircraft, and ultralight aircraft) due to their compact size, high power-to-weight ratio, reduced number of moving parts, and the ability to operate with different fuels. This work presents a 0D/1D methodology for simulating the gas exchange, combustion, and unsteady flow of a two-stroke aviation engine. The scavenging and combustion processes, as well as the unsteady flow within the induction and exhaust systems, are investigated using a 0D/1D modeling approach. This study is motivated by the need to assess the accuracy of such models in predicting engine performance. For this purpose, the thermo-fluid dynamic code GASDYN has been applied and enhanced. The proposed 0D model is embedded into a 1D fluid-dynamic code for simulating the entire engine system. To characterize the baseline configuration, which includes tangential ports that facilitate a loop-scavenging process, computed results
Cerri, TarcisioGiussani, AlessandroLucchini, TommasoMarinoni, AndreaMontenegro, GianlucaOnorati, Angelo
The two-stroke engine, known for its small displacement and high performance, is space-efficient when installed in a vehicle. As such, incorporating two-stroke engines into HEVs is an effective way to reduce vehicle weight and optimize engine space. However, one downside is that the amount of unfired elements in the exhaust gas increases due to the air/fuel mixture being expelled into the exhaust system during the scavenging process. Moreover, combustion can become unstable due to the large volume of residual burned gases in the cylinder. To address these issues, we propose a two-stroke engine equipped with intake and exhaust valves that directly inject fuel into the cylinder. In our first report, we presented an engine design and method that enable high scavenging efficiency and stable combustion in a two-stroke engine [1]. In this second report, we share the results of our research aimed at improving fuel efficiency and achieving low emissions, all while maintaining the high
Sakurai, YotaHisano, AtsushiSaitou, MasahitoIchi, Satoaki
In order to improve engine emission and limit combustion instabilities, in particular for low load and idle conditions, reducing the injected fuel mass shot-to-shot dispersion is mandatory. Unfortunately, the most diffused approach for the hydraulic analysis of low-pressure injectors such as PFIs or SCR dozers is restrained to the mean injected mass measurement in given operating conditions, since the use of conventional injection analyzers is unfeasible. In the present paper, an innovative injection analyzer is used to measure both the injection rate and the injected mass of each single injection event, enabling a proper dispersion investigation of the analysed low pressure injection system. The proposed instrument is an inverse application of the Zeuch’s method, which in this case is applied to a closed volume upstream the injector, with the injector being operated with the prescribed upstream-to-downstream pressure differential. Further, the injector can inject freely against air
Postrioti, LucioMaka, CristianMartino, Manuel
To mitigate greenhouse emissions such as carbon monoxide (CO), carbon dioxides (CO2), oxide of nitrogen (NOx) and particulate matter reduction Government of India implemented Bharat Stage VI (BS-VI) norms from year 2020. Moving to more stringent emission norms poses challenges for automakers in several ways such as meeting exhaust emissions, on board diagnostic, drivers’ inducement, and particulate filter monitoring on vehicle. It is imperative to upgrade engine management system for on-board diagnostics (OBD) that refers to a vehicles self-diagnostic and reporting ability. On board diagnostics systems enables owner of vehicle to gain access of the various vehicle sub-systems. OBD-II standards were made more rigid, requiring the malfunction indicator lamp (MIL) to be activated if emission-related components fail. Also, vehicle emissions carbon monoxide (CO), oxide of nitrogen (NOx) and particulate matter not to exceed OBD thresholds. Consequently, the use of specific oxide of nitrogen
Jagtap, PranjalSyed, KaleemuddinChaudhari, SandipKhairnar, GirishBhoite, VikramReddy, Kameswar
The use of MAN-type loop scavenging port arrangements in a 125 cc two-stroke racing engine is being investigated. These make it possible to provide larger cross-sections for the transfer ports, but at the expense of the exhaust port cross-section. The investigation is carried out using 1D calculations with GT-Suite. It is shown that significantly higher maximum outputs are possible in this way. However, this requires large exhaust widths, as otherwise the exhaust port is too small and the advantage of the larger transfer cross-section is overcompensated. Mixed forms between the original MAN loop scavenging and Schnürle loop scavenging can represent a good compromise. To improve the power characteristic vs. speed, which is influenced negatively by the higher maximum outputs, optimizations of port heights and exhaust pipe dimensions are carried out. A configuration with the same maximum output as the basis but a wider power band is also shown. One open point is the quality of the
Eilts, Peter
In response to the stringent CO2 regulations set to be enforced in Europe in 2030, there is a global demand for innovative technologies to significantly reduce CO2 emissions from internal combustion engines used in trucks, ships, and other applications. For this reason, future power sources are anticipated to adopt a three-pronged approach: electrification; hydrogen fuel used in fuel cells or internal combustion engines; and synthetic fuels (e-fuels) produced from renewable energy-sourced hydrogen, as approved by the European Commission (EC), and from raw materials that capture CO₂ directly from the atmosphere via the Direct Air Capture (DAC) method, combined with internal combustion engines. In this study, we aimed to absorb and capture “Green” CO₂ emissions from e-fuel and carbon-neutral (CN) fuels combined with internal combustion engines by investigating a method that atomizes a CO₂-absorbing solution. This approach involved spraying the solution and impingement the droplets within
Nohara, TetsuoNara, ShotaroKawamoto, YukiFukushima, NaoyaOchiai, Masayuki
This numerical study investigates a spark-ignited, two-stroke engine employing uniflow scavenging, flathead cylinder head design, and an exhaust valve system to identify the optimal bore-to-stroke (B/S) ratio for maximizing brake efficiency at fixed displacement. A single-cylinder prototype engine was constructed, and its experimental data validated a 1D GT-SUITE simulation model. This validated model was then utilized to simulate a full-scale, 1.5-liter displacement, horizontally opposed four-cylinder engine with supercharger-assisted boosting, intended for small aircraft propulsion. The simulations explored a range of B/S ratios from undersquare (0.7) to oversquare (1.5), maintaining a consistent brake power output of 60 kW at 3000 rpm and lambda 0.9. Results showed that increasing the B/S ratio enhanced brake efficiency from 26.0% at B/S=0.7 to 27.0% at B/S=1.5, largely due to reduced frictional losses attributed to shorter stroke and lower piston speeds, decreased heat transfer
Zanchin, GuilhermeHausen, RobertoFagundez, Jean LuccaLanzanova, ThompsonMartins, Mario
The objective of this study is to enhance the full-load power and the partial-load thermal efficiency of a gasoline spark-ignition engine for large motorcycles. To achieve these goals, it is important to increase the combustion speed and mitigate knocking, so a passive pre-chamber jet combustion system was evaluated. In the specification study, a three-dimensional combustion simulation incorporating detailed chemical kinetics was used to analyze the combustion mechanism, including knocking detection. For full-load conditions, a passive pre-chamber jet combustion system was evaluated. It accelerated combustion by increasing turbulent kinetic energy in the main chamber through jets sprayed from the pre-chamber. By increasing the compression ratio by 2.0, the full-load indicated work increased by 3.6% compared to conventional SI combustion. Under partial-load conditions, the passive pre-chamber jet combustion system faced challenges, such as reduced jet temperature due to increased
Ando, HirokazuTanaka, TakumiTomizawa, KengoInoue, Yosuke
A cold start occurs when the engine is cranked after being off for a long time, enough for its temperature to drop down to the cold ambient levels. Cold start in an engine is a critical phase as it is characterized by elevated emissions. During a cold start, exhaust components such as catalytic converter do not operate in its optimal temperature zone leading to reduced efficiency in emission control. New regulations for engine emissions are becoming stringent for this condition, hence it is important to accurately determine cold start condition in an engine to optimize the emissions control strategy. Accurate engine off time calculation plays a crucial role in cold start detection, emissions control and On-Board Diagnostics (OBD-II) decision making. This engine off time if greater than 6 hours indicates one of the conditions to confirm a cold start. Other conditions such as Ambient temperature and coolant temperature along with the engine off time confirms a cold start. This paper
MUTHA, MAYURESHTalawadekar, PradnyaKale, Upendra
Eaton's decompression engine braking technology for medium and heavy-duty diesel engines delivers high braking power and provides several advantages to the commercial truck owner. Eaton offers rocker arm-based 1 stroke, 1.5 stroke, and 2 stroke systems for overhead cam and cam in block engine architectures. The Compression Release (CR) engine brake avoids overheating and fading of primary friction brake. It reduces or eliminates the need for a driveline retarder. One of the failure modes for Engine Brake (EB) system is excessive lateral displacement of the exhaust valve, caused by non-uniform pressure distribution across the valve during Brake Gas Recirculation (BGR) and Compression Release modes. This excessive deformation is referred to as Valve Wagging. Valve wagging significantly affects the structural stability of the engine brake mechanism. Analyzing its behavior is essential to minimize excessive wear on valve guide and Valve Seat Insert in new designs. Since evaluating the
Soni, Lalitkumar R.Joshi, HimanshuJ, GokulakrishnanDe Giovanni, Pierfrancesco
In order to further understand the effect of twin-scroll turbocharging on the engine performance, this paper adopts a combination of one-dimensional numerical simulation and experimental research methods to compare the effects of two-scroll and single-scroll turbocharging on the power and fuel economy of direct injection gasoline engine. The research results show that, compared with the single-scroll turbocharger, twin-scroll turbocharger increased the low-end torque for 16% and 32% at 1000 r/min and 1500 r/min, respectively. However, the average fuel consumption has increased 1.3% at part load with twin-scroll turbocharger due to the pumping loss. Compared with a turbocharged port injection engine with a displacement 1.2 times that of the former, the twin-scroll turbocharged engine saved 11% fuel economy at part loads. The fuel consumption is saved 11% at part loads with twin-scroll turbocharger. This research first establishes the 1D simulation capability in twin-scroll turbocharger
Yu, Xiaocao
The United States Environmental Protection Agency (US-EPA) requires nitrogen oxides (NOx) measurement using Chemiluminescent Detectors (CLDs), Non-dispersive Ultraviolet (NDUV), and Zirconia Oxide (ZrO2) analyzers, as outlined in the 40 CFR Part 1065. Quantification of NO2 by CLD requires dual-CLDs; one dedicated to measuring the NO and another coupled with a NO2-to-NO converter to measure the total NOx. Measurement by using dual-CLDs involves mathematically subtracting NO from total NOx to get NO2 information. This requires perfect time alignments of both CLDs assigned for measuring NO and NOx to maintain accurate NO2 calculations. The NO2-to-NO converters can degrade over time and need to be replaced to get accurate total NOx measurement. In this study, Infra-red Laser Absorption Modulation (IRLAMTM) technology, which is an advanced QCL-IR spectroscopy proposed in the previous study [1], is used to measure NO and NO2 simultaneously in the exhaust gas of light-duty vehicles. This
Rahman, MontajirNevius, TimIsrael, JoshuaHara, KenjiNagura, Naoki
Heavy duty diesel engines provide a robust power plant for transportation applications for both on highway and off road applications. Control of criteria pollutants such as particulate matter and NOx at tailpipe for these applications based on standards set by regulatory bodies such CARB and EPA is critical. SwRI has demonstrated capability to achieve 0.02 g/bhp-hr. tailpipe NOx standard through the application of a model based controls in EPA and CARB funded projects. This control mechanism enables precise urea dosing for both steady state and transient conditions by leveraging estimated ammonia storage state in a dual dosing system using a set of chemical kinetics-based SCR observer models. This controller is highly nonlinear, with a significant amount of controller tuning with up to 55 calibratable parameters. In order to improve the accuracy and reduce the time required for calibration of this controller, this work proposes the deployment of a Deep Learning-based SCR plant model in
Chundru, Venkata RajeshRajakumar Deshpande, ShreshtaSharp, ChristopherGankov, Stanislav
On-Board Diagnostic (OBD) strategies utilize a predictive model to estimate engine out NOx levels for a given set of operating conditions to ensure the accuracy of the Nitrogen Oxides (NOx) sensor. Furthermore, this model is also used to determine urea dosing quantities in situations where the NOx sensor is unavailable such as cold starts or as a reaction to a NOx sensor plausibility failure. Physics-based NOx prediction models guarantee high levels of accuracy in real-time but are computationally expensive and require measurements generally not available on commercial powertrains making them difficult to implement on controllers. Consequently, manufacturers tend to adopt a mathematical approach by estimating NOx under standard operating conditions and use a variety of correction factors to account for any changes that can influence NOx production. Such correction factors tend to be outcomes of base engine calibration settings or outputs of models of other related sub systems and may
Sunder, AbinavSuresh, RahulPolisetty, Srinivas
The free-piston engine is an innovative type of internal combustion engine, which has great potential in structural flexibility and energy diversity. The power density and combustion efficiency of the free-piston engine are primarily affected by the scavenging process. The computational fluid dynamics method is used to optimize the scavenging process of a two-stroke free-piston engine, which features a dual-cylinder opposed structure and is equipped with an electromagnetic valvetrain. The valve timing and port inclination angle are optimized by utilizing the scavenging efficiency and circulation intake mass as the main evaluation indicators. The results indicate that the short-circuit loss in the loop scavenging mode is relatively severe, which leads to a low trapping efficiency of only about 40%. By modifying the valve timing, a better scavenging performance can be achieved with a higher scavenging efficiency and a larger circulation intake mass, with the scavenging efficiency
Xu, ZhaopingWang, XiaoyanLiu, Liang
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