bluuebunny/crossref_metadata_2025 huggingface dataset:
On-Track Demonstration of Automated Eco-Driving Control for an Electric Vehicle
Authors: JEONG Jongryeol , Dudekula Ahammad Basha , Kandaswamy Elangovan , Karbowski Dominik , Han Jihun , Naber Jeffrey
Published: April 2023

This paper presents the energy savings of an automated driving control applied to an electric vehicle based on the on-track testing results. The control is a universal speed planner that analytically solves the eco-driving optimal control problem, within a receding horizon framework and coupled with trajectory tracking lower-level controls. The automated eco-driving control can take advantage of signal phase and timing (SPaT) provided by approaching traffic lights via vehicle-to-infrastructure (V2I) communications. At each time step, the controller calculates the accelerator and brake pedal position (APP/BPP) based on the current state of the vehicle and the current and future information about the surrounding environment (e.g., speed limits, traffic light phase). The target vehicle is a Chevrolet Bolt, an electric vehicle, which is outfitted with a drive-by-wire (DBW) system that allows external APP/BPP to command the speed of the vehicle, while the operator remains in charge of the steering wheel. The DBW is connected to a rapid prototyping unit by dSpace. This unit includes: (1) real-time software that gathers all digital and analog sensors, as well as signals from the CAN bus; (2) a simple digital twin representation of the track; and (3) automated driving controls. The digital twin representation includes virtual stop signs, speed limits, and traffic lights. The digital twin can broadcast information about current and future road environment (e.g. SPaT) based on the actual position of the vehicle on the track, and correlate that to a position in the digital twin. The automated driving controls include eco-driving controls and an additional safety-focused control layer. The experiments include five road scenarios, and three control calibrations, and each combination is repeated three times. The road scenarios are all within 3.7 km in length, corresponding to one full loop around an oval track at the American Center for Mobility in Michigan, and feature various combinations of stop signs, traffic signals, and speed limits. The control calibrations correspond to a human-driver-like baseline, non-connected automated driving, and automated driving with V2I connectivity. Test-to-test variability is within 2%, thanks to careful thermal conditioning of the vehicle prior to tests. Functionality is verified and demonstrated: no excessive jerk and no violations of traffic laws occur. Energy savings of up to 7% are demonstrated in the no-connectivity case, and up to 22% in the V2I connectivity case. These tests demonstrate the real-world energy-saving potential of automated eco-driving controls.
Combustion Regimes in the Chrysler Multi-Air Multi-Fuel Engine, Part 2 - Diesel Micro-Pilot Combustion
Authors: Church William , McConnell Steven
Published: April 2023

This paper is the second of three papers stemming from a dual fuel Chrysler prototype engine which uses both diesel and gasoline direct injection running at near-stoichiometric conditions, as part of a project to explore the viability of incorporating an engine platform which utilizes low temperature combustion regimes into a modern automotive application. The combustion system was designed to tolerate high rates of EGR while maintaining combustion stability by using high charge motion intake port and a high energy ignition system. The engine ran on highly dilute SI combustion at low loads, Diesel Assisted Spark Ignition at medium loads and a transition to Diesel Micro Pilot ignition at medium to high load. The first paper explored the use of Diesel Assisted Spark Ignited at moderate loads 6.5 bar to 12.7 bar BMEP and the third paper to be published in 2024 will explore fuel property effects (mainly Cetane and Octane) through the use of alternative fuels. This paper explores the use of DMP at high loads 10.6 to 14.5 bar BMEP. In the Diesel Micro-Pilot mode, a small quantity diesel injection is used to initiate the combustion of a gasoline-air mixture. Testing was accomplished for engine speeds of 2000 RPM and 2400 RPM with boost levels of 180 kPa to 220 kPa. The engine was optimized to operating points using diesel injection timing and diesel percentage of total fuel mass. Results are presented for both brake thermal efficiency and emissions data. The engine produced brake thermal efficiency levels of 40%.
Research and Analysis on Hydraulic System of a Two-Stage Variable Compression Ratio Engine
Authors: Luo Haipeng , Zhan Wenfeng , Wu Guangquan
Published: April 2023

This study introduces the working principle of the two-stage variable compression ratio system, the layout and method of the VCR hydraulic system test. Based on the research and analysis of VCR hydraulic system test, the results shows the average pressure, degree of pressure fluctuation of the VCR conrod supply oil and the temperature of conrod journal are all strongly and positively related to engine speed. The maximum oil pressure fluctuation amplitude at VCR conrod bearing appears at 5500r/min. The temperature at VCR conrod bearing is mainly dominated by the friction between bearing and crankshaft, and its maximum value appears at 6000r/min; Meanwhile, the main contribution of engine load to the temperature is to increase temperature of the whole circle of conrod journal, and also reducing temperature difference of the whole circle. In addition, the state change of VCR hydraulic system under different conditions can reflect the state of engine compression ratio. The results of overall test show that oil pressure fluctuation of the VCR hydraulic system is in normal range, the system has good function and can meet the oil demand of each sub-component under steady and dynamic conditions.
A Numerical Investigation of Gas Exchange Modeling and Performance Prediction of a Camless Two-Stroke Hydrogen Engine
Authors: Tripathy Srinibas , Koopmans Lucien , Hemdal Stina , Kuylenstierna Claes
Published: April 2023

Heavy-duty vehicles are primarily powered by diesel fuel, emitting CO2 emissions regardless of the exhaust after-treatment system. Contrastingly, a hydrogen engine has the potential to decarbonize the transportation sector as hydrogen is a carbon free, renewable fuel. In this study, a multi-physics 1D simulation tool (GT-Power) is used to model the gas exchange process and performance prediction of a two-stroke hydrogen engine. The aim is to establish a maximum torque-level for a four-stroke hydrogen engine and then utilize different methods for two-stroke modeling to achieve similar torque by optimizing the gas exchange process. A camless engine is used as base, enabling the flexibility to utilize approximately square valve lift profiles. The preliminary step is the GT-Power model validation, which has been done using diesel and hydrogen engines (single-cylinder heavy-duty) experiments at different operating points (871 rpm, 1200 rpm, 1259 rpm, and 1508 rpm). Thereafter, the validated model is used to simulate four-stroke hydrogen engine performance at different intake and exhaust pressures. The last step was to modify the model to operate in two-stroke mode. The intake and exhaust valve closing timings, pressure differential, and air-fuel equivalence ratio were varied to investigate the delivery ratio, charging efficiency, trapping efficiency, and scavenging efficiency for perfect displacement and perfect mixing modes. The variable valve-actuated camless two-stroke hydrogen engine achieved similar torque to that of a conventional cam-operated four-stroke hydrogen engine by optimizing valve timings, pressure differential, and in-cylinder air-fuel mixture proportions.
Experimental Demonstration of a High-Efficiency Split-Intake D-EGR Engine Concept
Authors: Handa Gaurav , Conway Graham , Robertson Dennis , Gukelberger Raphael
Published: April 2023

Dedicated-EGR™ (D-EGR™) is a concept where the exhaust of one dedicated cylinder (D-Cyl) is routed into the intake thus producing EGR to be used by the whole engine. The D-Cyl operates rich of stochiometric which produces syngas that enhances the EGR stream permitting faster combustion and greater knock mitigation. Operating an engine using D-EGR improves the knock resistance which can permit a higher compression ratio (CR) thereby increasing efficiency. One challenge of traditional D-EGR is that the D-Cyl combustion becomes unstable operating with both rich and EGR dilute conditions. Therefore, the ‘Split Intake D-EGR’ concept seeks to resolve this problem by feeding fresh air to the D-Cyl, thus allowing even richer operation in the D-Cyl which further increases the H2 and CO yield thereby enhancing the efficiency benefits.

This concept was employed on a downsized PSA EP6CDTx 1.6 L gasoline engine with a baseline BMEP of 20 bar, a CR of 10.5:1, and a peak brake thermal efficiency (BTE) of 36%. After a careful analysis of the CR feasible for the baseline engine, the CR for the D-Cyl was increased from 10.5:1 to 12:1. Furthermore, at both part-load and knock-limited conditions, the Split Intake D-EGR strategy demonstrated better engine BTEs in comparison with the conventional D-EGR and baseline external and internal EGR systems. Proper implementation of the Split Intake D-EGR strategy led to a BTE increase to 39.64% from the baseline of 36%.

Apart from the efficiency benefits, the other advantage of running a Split Intake D-EGR system is that the dedicated cylinder could be operated independently of the main cylinders due to the additional throttle for the D-Cyl. An imbalanced IMEP approach was explored during this study where the dedicated cylinder was operated at a 40% higher IMEP compared to the main cylinders, thus producing more EGR for a given operating condition.
Characterization of High-Tumble Flow Effects on Early Injection for a Lean-Burn Gasoline Engine
Authors: MacDonald James Richard , White Logan , Ekoto Isaac , Pickett Lyle , Oh Heechang , Han Donghee
Published: April 2023

The influence of early induction stroke direct injection on late-cycle flows was investigated for a lean-burn, high-tumble, gasoline engine. The engine features side-mounted injection and was operated at a moderate load (8.5 bar brake mean effective pressure) and engine speed (2000 revolutions per minute) condition representative of a significant portion of the duty cycle for a hybridized powertrain system. Thermodynamic engine tests were used to evaluate cam phasing, injection schedule, and ignition timing such that an optimal balance of acceptable fuel economy, combustion stability, and engine-out nitrogen oxide (NOx) emissions was achieved. A single cylinder of the 4-cylinder thermodynamic engine was outfitted with an endoscope that enabled direct imaging of the spark discharge and early flame development. Tejhese measurements were complemented by optical-engine tests used to directly measure the impact of fuel injection dynamics on late-cycle flows via a combination of particle image velocimetry and diffuse back-illuminated extinction imaging techniques. From the optical imaging measurements, different interaction modes between the tumble vortex and liquid fuel spray were identified that were found to persist late into the compression stroke and directly influence velocity fields in the vicinity of the spark plug at the time of ignition. These modal interactions strongly depended on injection timing, with advanced injection timings relative to the optimal found to destructively interfere with the tumble vortex, which in turn compromised late-cycle spark plug flow development and was attributed to the significant deterioration in combustion stability during the thermodynamic engine tests. These results highlight the critical importance of spray targeting with respect to tumble vortex location.
Ultra-High Fuel Pressure in GDI to Suppress Particulate Formation during Warming-Up and Load Transients
Authors: Yamaguchi Akichika , Dillner Johan , Helmantel Arjan , Koopmans Lucien , Dahlander Petter
Published: April 2023

This study investigates if particulates from a GDI engine can be significantly suppressed by use of ultra-high injection pressures under 2 different engine conditions known to be associated with high particulate numbers (PN): warm-up and transients. Experiments were carried out in a single-cylinder GDI engine equipped with an endoscope connected to a high-speed camera to enable combustion visualization. To mimic the warming-up, the coolant temperature was varied between 20 °C and 90 °C. A Diesel injector with modified nozzle was used and the injection pressures were varied between 400 and 1500 bar.

The results revealed that increasing the fuel injection pressure decreased engine out HC and PN under warming-up conditions. However, the coolant water temperature was the most dominant factor affecting the emissions. For coolant temperature of 20 °C, the use of 1500 bar fuel injection pressure in comparison to lower fuel pressures resulted in significantly lower PN.

The simplified load transients were studied with motoring followed by combustion. The results revealed that increasing the fuel pressure significantly suppressed the occurrence of luminosity from soot. After ca 40 combustion cycles, the luminosity had decreased significantly due to increased combustion surface temperatures and the decrease was more significant when the fuel pressure was increased. Overall, the results suggested that an increased fuel injection pressure is beneficial under warming-up and simplified load transient conditions as well as under hot conditions.
Preheated Liquid Fuel Injection Concept for Lean Pre-chamber Combustion
Authors: Hlaing Ponnya , Ravenhill Paul , Larsson Peter , Cenker Emre , AlRamadan Abdullah , Im Hong , Turner James
Published: April 2023

The pre-chamber combustion (PCC) concept is a proven lean or diluted combustion technique for internal combustion engines with benefits in engine efficiency and reduced NOx emissions. The engine lean operation limit can be extended by supplying auxiliary fuel into the pre-chamber and thereby, achieving mixture stratification inside the pre-chamber over the main chamber. Introducing liquid fuels into the pre-chambers is challenging owing to the small form factor of the pre-chamber. With a conventional injector, the fuel penetrates in liquid form and impinges on the pre-chamber walls, which leads to increased unburned hydrocarbon emissions from the pre-chamber. In this study, a prototype liquid fuel injector is introduced which preheats the fuel within a heated chamber fitted with an electrical heating element before injecting an effervescently atomized spray into the pre-chamber. The experiments were conducted in a heavy-duty pre-chamber research engine using ethanol as the primary fuel. In the first set of experiments, only the pre-chamber was fueled to investigate the influence of injector operating parameters on the mass of fuel injected and the stability of the fuel flow rate. In the second set of experiments, fuel was supplied to both the pre- and the main chamber to investigate the engine performance at different air-fuel ratios at a fixed intake airflow. As a proof of concept, preheating the fuel prior to injection into the pre-chamber was found to improve the combustion stability with simultaneous reductions in engine-out unburned fuel and carbon monoxide emissions while requiring only low power requirements for effective fuel preheating.
On-Road CO 2 and NO x Emissions for a Heavy-Duty Truck with Hydrogen-Diesel Co-Combustion
Authors: Kheirkhah Pooyan , Steiche Patrick , Whyte Tyson , Guan Mang , Kirchen Patrick
Published: April 2023

Heavy-duty diesel trucking is responsible for 25%-30% of the road transportation CO2 emissions in North America. Retrofitting class-8 trucks with a complementary hydrogen fuelling system makes it possible to co-combust hydrogen and diesel in the existing internal combustion engine (ICE), thus minimizing the costs associated with switching to non-ICE platforms and reducing the barrier for the implementation of low-carbon gaseous fuels such as hydrogen. This retrofitting approach is evaluated based on the exhaust emissions of a converted truck with several thousand kilometres of road data.

The heavy-duty truck used here was retrofitted with an air-intake hydrogen injection system, onboard hydrogen storage tanks, and a proprietary hydrogen controller enabling it to operate in hydrogen-diesel co-combustion (HDC) mode. The hydrogen controller operates on the J1939 network, similar to the OEM Controller Area Network (CAN) and determines the hydrogen injection rate from hydrogen energy share ratio (RH2) tables based on engine-related parameters.

The cycle-total RH2 for the considered in-use operation ranged from 15% to 28%, with a maximum instantaneous value of close to 40%. This range of RH2 has been explored in engine-dynamometer studies in the literature showing promising results without negative combustion anomalies. Here, the real-drive exhaust CO2 and NOx emissions during the HDC operation were compared to those for the neat diesel operation. The OEM sensors were used for on-road exhaust NOx measurement, and their accuracy and cross-sensitivity to interfering gaseous species were examined in controlled laboratory experiments. The road data shows that the exhaust NOx emissions during the HDC operation are reduced compared to the neat diesel baseline, and the tailpipe CO2 reductions are directly correlated to the hydrogen substitution rates.
GDI Ammonia Spray Numerical Simulation by Means of OpenFOAM
Authors: Pandal Adrian , Zembi Jacopo , Battistoni Michele , Hespel Camille , Pele Ronan , BREQUIGNY Pierre , Rousselle Christine
Published: April 2023

The goal of mitigating climate change has driven research to the use of carbon-free energy sources. In this regards, green hydrogen appears as one of the best options, however, its storage remains difficult and expensive. Indeed, there is room to consider the use of ammonia (an efficient hydrogen carrier) directly as a fuel for internal combustion engines or gas turbines. Currently, there are very few works in the literature describing liquid ammonia sprays, both from experimental and modeling point of view, and especially dealing with flash-boiling conditions. In this research work, the direct injection ammonia spray is modeled with the Lagrangian particle approach, building up a numerical model within the OpenFOAM framework, for transient analyses using the U-RANS approach. An evaluation of main spray modeling parameters is carried out to build a predictive Lagrangian model for ammonia based on the comparison with experiments in terms of liquid and vapor tip penetration, local values of Sauter mean diameter and global spray morphology. In this work, results of CFD simulations of ammonia spray and the comparison with experimental data are presented for different conditions, aiming to present a comparison between flash boiling and non-flashing regimes.
Prediction of Spray Vapor Tip Penetration of Diesel, Biodiesel and Synthetic Fuels Using Artificial Neural Networks with Confidence Intervals
Authors: Richards Bryn , Emekwuru Nwabueze
Published: April 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 variability and limitations in the neural network training process. This has not been presented previously, and it allows the calculation of confidence intervals on the spray penetration predictions produced by neural networks. Using the present method, we evaluate four different diesel, biodiesel and OME fuel blends under four fuel injection conditions each and predict spray vapor tip penetration values with a correlation coefficient of 0.999. Across all fuel variants and injection conditions, one standard deviation represented less than 1.5 mm spray tip penetration (circa 2% of spray tip penetration) 1 ms from the start of injection. Despite this precision, a 95% confidence interval on neural network predictions encompassed the experimental fuel penetration data across all fuel variants, injection conditions and time steps. By calculating the confidence intervals on neural network predictions, we enable internal combustion engine designers to better quantify the applicability of neural networks in predicting spray characteristics.
NH

3

Impact on Combustion and Emission Characteristics of N-Heptane Flame
Authors: Akram M. Zuhaib , Deng Yangbo , Aziz Muhammad , Ge Bingquan , Jiang Hao
Published: April 2023

Soot and carbon dioxide released from internal combustion engines became the key issues when using fossil fuels. The use of zero-carbon fuel, ammonia, with hydrocarbon fuels may play an important role in reducing the exhaust effect on the environment and mitigating the reliance on nonrenewable energy resources. However, ammonia reduces the flame speed of hydrocarbon fuels. A numerical approach was executed to study the ammonia impact on n-heptane, a diesel surrogate, flame. A kinetic mechanism was prepared by adding the sub-mechanism of ammonia, NO2 and NO3 emissions, and soot precursors to the n-heptane kinetic mechanism. The modified Arrhenius equation and soot surface reactions were used to study the soot formation with NOx emissions. The results showed that ammonia decreased the fractions of carbon-related species and raised the concentration of non-carbon-related species. Therefore, CO and CO2 emission species reduced, whereas the fraction of non-emission species, H2O, increased at the end of combustion. From 0% to 50% addition of NH3 in n-heptane fuel deteriorated about 36% soot and NO3 emissions with only a 17% reduction in the laminar burning velocity. When the ammonia contents increased from 50% to 90%, the reduction in exhaust gas emissions and the burning velocity were around 57% and 37%, respectively. It is concluded by the current study that the dilution of ammonia in n-heptane fuel should be equal to or less than 50% because a higher reduction in CO, CO2 and NOX emissions can be achieved with a small reduction in burning velocity.
Measurement of Hydrogen Direct Injection Jet Equivalence Ratio under Elevated Ambient Pressure Condition
Authors: Lee Sanguk , Kim Jungho Justin , Ki Youngmin , Kwak Yeseung , Lee Seong-Young
Published: April 2023

Owing to climate change issues caused by global warming, the role of alternative fuels, such as low-carbon and non-carbon fuels, is becoming increasingly important, particularly in the transportation sector. Therefore, hydrogen has emerged as a promising fuel for internal combustion engines because it does not emit carbon dioxide. Direct injection is mandatory for hydrogen-based internal combustion engines to mitigate backfires and low energy density. However, there is a lack of measurement of the equivalence ratio methodology because hydrogen has a higher diffusion rate than conventional fuels. The objective of this research is a feasibility study of laser-induced breakdown spectroscopy (LIBs) for measuring the equivalence ratio. The second harmonic ND-YAG laser was implemented to induce the atomic emission of hydrogen via the breakdown phenomenon. Simultaneously, the hydrogen jet structure was visualized in a constant volume vessel using Schlieren imaging. Therefore, the experimental results have both measurement location and equivalence ratio information. High-speed Schlieren imaging indicated a highly contracted jet structure under elevated-ambient-pressure conditions. Meanwhile, the local-rich mixture was detected only when the ambient pressure was high due to jet contraction. By contrast, hydrogen does not exist in the core region of the jet because the nozzle has a hollow cone shape under low-ambient-pressure conditions. According to preliminary experimental results, the direct-injected hydrogen jet can be measured using LIBs. However, there was a clear limitation because only the local point area could be measured using LIBs. Despite this apparent limitation, LIBs can contribute to promoting hydrogen-based internal combustion engines to meet the carbon neutrality target by 2050.
Nitrogen Oxides Emission Characteristics of Zero-Carbon Ammonia-Hydrogen Fuels for Internal Combustion Engines
Authors: Yan Yuchao , Yang Ruomiao , Liu Zhentao , Liu Jinlong
Published: April 2023

As a zero-carbon fuel and a hydrogen derivative, ammonia is promising for large-scale use in internal combustion engines under the global decarbonization background. Although ammonia fuel itself does not contain elemental carbon and cannot produce carbon dioxide, it contains elemental nitrogen and produces nitrogen oxides (NOX) emissions during combustion. Accordingly, it is essential to understand the formation and evolution of NOX during ammonia oxidation as a prerequisite for finding solutions to control NOX emissions. Since the emission formation is chemically reaction-driven, this paper investigates the ammonia low and high temperature oxidation processes via laminar flame and ideal reactor models, which can provide steady-state NOX formation characteristics to be studied and eliminate unpredictable turbulence and gradients of species concentration and temperature in the engine combustion chamber. Moreover, this study investigates the ammonia combustion process under thermodynamic conditions representative of the engine in-cylinder environment. One challenge in understanding the NOX formation mechanism during ammonia combustion is the coupling of fuel NOX (i.e., nitrogen from ammonia) and thermal NOX (i.e., nitrogen from the atmosphere). The main innovation of this article is the introduction of a methodology to decouple fuel nitrogen and atmospheric nitrogen. The results prove that this method is effective regardless of the operating conditions. In addition, unlike the thermal NOX whose concentration is related to temperature and residence time, fuel NOX, especially nitric oxide (NO) and nitrous oxide (N2O), are important intermediate species and are active in the reaction zone and during ignition. Furthermore, the concentration of fuel NOX and thermal NOX are of comparable order of magnitude and they are sensitive to the combustion boundary conditions (e.g., temperature, equivalence ratio, and hydrogen addition). Specifically, increasing the temperature favors the thermal NOX formation, and fuel-rich operation reduces both fuel NOX and thermal NOX concentrations. Also, mixing ammonia with hydrogen can increase fuel NOX and thermal NOX levels simultaneously. Consequently, the cost of using hydrogen as a combustion promoter to improve the ammonia chemical reactivity is to increase the difficulty of NOX emission control. Overall, all of these findings support the need for further fundamental research on ammonia combustion to accelerate the engine transition to carbon neutrality.
Experimental Comparison of Diesel and Wet Ethanol on an Opposed-Piston Two Stroke (OP2S) Engine
Authors: Gainey Brian , Bhatt Ankur , Gandolfo John , Vedpathak Kunal , Pearce Christopher , Redon Fabien , Lawler Benjamin
Published: April 2023

Renewable fuels, such as the alcohols, ammonia, and hydrogen, have a high autoignition resistance. Therefore, to enable these fuels in compression ignition, some modifications to existing engine architectures is required, including increasing compression ratio, adding insulation, and/or using hot internal residuals. The opposed-piston two-stroke (OP2S) engine architecture is unique in that, unlike conventional four-stroke engines, the OP2S can control the amount of trapped residuals over a wide range through its scavenging process. As such, the OP2S engine architecture is well suited to achieve compression ignition of high autoignition resistance fuels. In this work, compression ignition with wet ethanol 80 (80% ethanol, 20% water by mass) on a 3-cylinder OP2S engine is experimentally demonstrated. A load sweep is performed from idle to nearly full load of the engine, with comparisons made to diesel at each operating condition. These results indicate that on the OP2S architecture, wet ethanol 80 produces near-zero soot and reduces engine-out NOx emissions by a factor of 3-5. Due to the combustion chamber geometry, which is optimized for diesel combustion, most of the fuel was injected near top dead center for a diffusion-style heat release process. Therefore, there is 1-3 percentage point thermal efficiency penalty associated with wet ethanol 80’s longer diffusion heat release process, since the nozzle hole size of the injector was not increased, and from evaporation-driven heat removal near top dead center. However, further optimization of the injectors and combustion chamber geometry could mitigate or eliminate this efficiency penalty by enabling a larger fraction of the total fuel to be injected earlier in the compression stroke.
Machine Learning for Fuel Property Predictions: A Multi-Task and Transfer Learning Approach
Authors: Larsson Tara , Vermeire Florence , Verhelst Sebastian
Published: April 2023

Despite the increasing number of electrified vehicles the transportation system still largely depends on the use of fossil fuels. One way to more rapidly reduce the dependency on fossil fuels in transport is to replace them with biofuels. Evaluating the potential of different biofuels in different applications requires knowledge of their physicochemical properties. In chemistry, message passing neural networks (MPNNs) correlating the atoms and bonds of a molecule to properties have shown promising results in predicting the properties of individual chemical components. In this article a machine learning approach, developed from the message passing neural network called Chemprop, is evaluated for the prediction of multiple properties of organic molecules (containing carbon, nitrogen, oxygen and hydrogen). A novel approach using transfer learning based on estimated property values from theoretical estimation methods is applied. Moreover, the effect of multi-task learning (MTL) on the predictions of fuel properties is evaluated. The result show that both transfer learning and multi-task learning are good strategies to improve the accuracy of the predicted values, and that accurate predictions for multiple fuel properties can be obtained using this approach.
Impact of Second NH
3
Storage Site on SCR NO
x
Conversion in an Ultra-Low NO
x
Aftertreatment System
Authors: Chundru Venkata Rajesh , Desai Chintan , Kadam Vaibhav , Vernham Bruce , Sharp Christopher , Rengarajan Sankar , Rao Sandesh , Sarlashkar Jayant
Published: April 2023

Typical two-site storage-based SCR plant models in literature consider NH3 stored in the first site to participate in NH3 storage, NOx conversion and second site to only participate in NH3 storage passively. This paper focuses on quantifying the impact of stored NH3 in the second site on the overall NOx conversion for an ultra-low NOx system due to intra site NH3 mass transfer. Accounting for this intra site mass transfer leads to better prediction of SCR out NH3 thus ensuring compliance with NH3 coverage targets and improved dosing characteristics of the controller that is critical to achieving ultra-low NOx standard. The stored NH3 in the second site undergoes mass transfer to the first site during temperature ramps encountered in a transient cycle that leads to increased NOx conversion in conditions where the dosing is switched off. The resultant NH3 coverage fraction prediction is critical in dosing control of SCR. This phenomenon is evaluated and quantified with different aging conditions, where the increased second site storage and reduced standard SCR activity due to hydrothermal aging leads to further increase in the reported phenomena. Although this phenomenon was observed for both light-off SCR (Lo-SCR) and downstream SCR based on analysis of the data, the impact on Lo-SCR performance was found to be higher compared to the downstream system due to the transient thermal conditions and higher temperatures experienced by the Lo-SCR system. This mass transfer mechanism also plays a role in determining NH3 slip characteristics of Lo-SCR for real world conditions where the gradual transfer of NH3 in the axial direction leads to NH3 slip. This phenomenon is demonstrated using experimental data collected on a production engine for a set of HFTP, CFTP, RMC and LLC cycles
Experimental Study on BETP Emission Factor and Breakthrough Law of Carbon Canister in American Standard
Authors: Zhong Chongzhi , Zhang Taiyu , LI Zhe , Wu Xiaoliang , sun Jiaxing , Chen Qiang , Zhao Xinwu
Published: April 2023

Diurnal evaporative testing of atmospheric fuel system with no-load canister for 14 days and half load canister for 7 days is carried out according to the US EPA BETP test procedure. In addition, the atmospheric fuel system and pressurized fuel system were tested for BETP for 72h diurnal evapration respectively.The results show that the total emissions of the atmospheric fuel system in 72h is 210mg, and the proportion of respiratory emissions is between 90% - 95%. The 72h total emissions of the pressurized fuel system is about 120mg, and the permeation emissions of the fuel tank accounts for about 82% - 90%. The total respiratory emissions of the atmospheric fuel system are 130.4 mg, mainly alkanes, accounting for 70% - 80%. The pressurized fuel system is dominated by the permeation emission of the fuel tank, with a total amount of 127.5 mg, mainly composed of alkanes, aromatic hydrocarbons and OVOCs, accounting for 45% - 50%, 43% - 47% and 3% - 5% respectively. In the canister breakdown test of gasoline vehicle fuel system, the THC emissions of no-load test and 7-day half load test are similar; the VOCs composition in the first 12 days is similar to that in the 3-day test, mainly alkanes. After the canister breakthrough, the proportion of aromatic hydrocarbons and OVOCs increases significantly.
Challenges of Particulate Number above 10nm Emissions for a China 6 Compliant Vehicle to Meet Future Regulation
Authors: Liu Haixu , Li Chunbo , Li Weiwei , Feng Xiangyu , Tao Tinghong , Boger Thorsten , Wang Guodong , li Gaojian , Yu Guangyao , Lu Heng , Li Ruike , Qiang Ren , Yuan Guanlian
Published: April 2023

As the official proposal for emission regulation Euro 7 has been released by European Commission, PN above 10nm is taken into consideration for the ultrafine particulate emissions control. The challenges of GPF filtration efficiency emerge for the light-duty manufactures to meet the future emission standards. In the present study, a China 6 compliant vehicle was tested to reveal its performance over the China 6 standards and potential to meet the upcoming Euro 7. Three GPF product types (Gen 1, Gen 2, and concept Gen 3) were mounted to the tested vehicle. WLTC tests were conducted on chassis dynamometer in laboratory as well as a self-designed aggressive cycle (“Base Cycle”) tests. To explore the GPFs performance for PN emissions above 10nm against the proposed limit 6.0E11 #/km, PN emission above 10nm were measured in our laboratory tests for both engine out and tailpipe as well as the PN emission above 23nm. In addition, worst case RDE tests were carried out on the real road with PEMS. It was found that, when including particles down to 10nm, further improvement is needed for the current system, and the Gen 2 and concept Gen 3 products could be a promising path to meet the proposed standards with much higher filtration efficiency. Combined with possibly further extended RDE boundary conditions in Euro 7, the test results suggested that higher filtration efficiency filter products are likely required to comply with the tightened emission regulations.
Real-world Cold Start Emissions Evaluation for Direct-injection Gasoline Vehicle with PEMS and SEMS
Authors: Chen Jiaxin , Sato Susumu , Eang Chanpaya , Tanaka Kotaro , Tange Takeshi
Published: April 2023

The Real Driving Emissions (RDE) test method has been introduced after 2017 to regulate the vehicle emissions in real-world driving situations by means of on-board emissions measurements. This paper aims to estimate the detailed on-board gaseous emissions from a light-duty direct-injection gasoline vehicle simultaneously using both portable emissions measurement system (PEMS) and sensor-based emissions measurement system (SEMS). Test route is typical urban route and tests environment factors followed the RDE regulation. Carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), and ammonia (NH3) emissions were analyzed according to cold start once and followed by hot start conditions. The mass emissions of gas components were calculated based on the exhaust flowrate obtained from OBD parameters, NH3 emission was calculated based on NO sensor’s data. Two drivers participated in the tests and their emissions difference has been compared. The results indicating cold start caused much more emission than hot start in CO, NOx and NH3; and aggressive driving behavior would cause more emissions. Simultaneous tests gave chances to better combine the advantages of both measurement systems, and figure out the cause of NH3 emission, two different patterns of NH3 emission which depending on cold/hot start method have been found, and the results showed CO emission and catalytic temperature can both be crucial factors to form NH3 in exhaust gas.
Evaluation of Indrio’s Ammonia Sensor using a Diesel Fuel Based Burner Platform
Authors: Premnath Vinay , Balakrishnan Arun , Sur Ritobrata , Khalek Imad , Eakle Scott
Published: April 2023

This program involved the detailed evaluation of a novel laser-based in-exhaust ammonia sensor using a diesel fuel-based burner platform integrated with an ammonia injection system. Test matrix included both steady-state modes and transient operation of the burner platform. Steady-state performance evaluation included tests that examined impact of exhaust gas temperature, gas velocity and ammonia levels on sensor response. Furthermore, cross sensitivity of the sensor was examined at different levels of NOX and water vapor. Transient tests included simulation of the FTP test cycles at different ammonia and NOX levels. A Fourier transform infrared (FTIR) spectrometer as well as NIST traceable ammonia gas bottles (introduced into the exhaust stream via a calibrated flow controller) served as references for ammonia measurement. Results suggested that Indrio’s sensor exhibits a strong linear relationship with reference ammonia measurement across the tested range of 0 ppm to 200 ppm with a regression factor (R2) ~ 0.99. Exhaust flowrate did not have a significant impact on sensor performance. With no temperature compensation applied, Indrio’s sensor performance was not impacted by temperatures of the order of 300°C to 400°C, however, it slightly overestimated ammonia levels at lower temperatures (~200°C). Cross-sensitivity experiments indicated that the presence of 200 ppm NOX resulted in less than 2.5% change in slope (Indrio sensor vs reference). Transient sensor response indicated that the sensor tracked reference ammonia concentration reasonably well. Overall, the sensor exhibited tremendous potential to serve as an accurate onboard ammonia sensor that could be used for real-time SCR control strategy optimization which will be invaluable for future low NOX platforms.
Study on Soot Oxidation Characteristics of Ce and La Modified Pt-Pd CDPF Catalysts
Authors: Lou Diming , Chen Yajuan , Zhang Yunhua , Wan Peng , Tan Piqiang , Hu Zhiyuan , Fang Liang , Wang Tong
Published: April 2023

The catalyzed diesel particulate filter with Pt and Pd noble metals as the main loaded active components are widely used in the field of automobile engines, but the high cost makes it face huge challenges. Rare earth element doping can improve the soot oxidation performance of the catalyzed diesel particulate filter and provide a new way to reduce its cost. In this paper, thermogravimetric tests and chemical reaction kinetic calculations were used to explore the effect of Pt-Pd catalysts doped Ce, and La rare earth elements on the oxidation properties of soot. The results shown that, among Pt-Pd-5%Ce, Pt-Pd-5%La, and Pt-Pd-5%Ce-5%La catalysts, Pt-Pd-5%La catalyst has the highest soot conversion, the highest low-temperature oxidation speed, and the activation energy is the smallest. Compared with soot, this catalyst reduced T10 and T20 by 82% and 26%, respectively, meaning the catalytic activity of Pt-Pd-5%La catalyst was the best. With the decrease of catalyst/soot ratios, the soot conversion and oxidation speed of Pt-Pd and Pt-Pd-5%La catalysts decreased, and characteristic temperature increased. In both catalyst formulations, samples with catalyst/soot ratio of 5 showed the best catalytic activity, and the other samples with smaller catalyst/soot ratios showed less difference. The study revealed the influence of doping elements and catalyst/soot ratios on the oxidation characteristics and reaction kinetics of soot, which has a guiding significance for optimizing the doping scheme of rare earth elements and realizing the reduction of noble metals.
Investigation of Equivalency between Laboratory-Grade and Portable Emissions Measurement Systems in Solid Particle Number Measurement Larger than 10 nm
Authors: Otsuki Yoshinori , Fukushima Suguru , Nakamura Hiroshi , Kojima Kentaro , Sakurai Hiromu
Published: April 2023

The measurement protocol of solid particle number with the lower detection limit (D50) at 10 nm (SPN10) is planned to be implemented in European emission regulations by means of laboratory-grade measurement systems. Furthermore, SPN10 measurement as the real driving emissions (RDE) regulations is under development by defining appropriate technical specifications for the portable emissions measurement system (PEMS). It is under discussion to implement SPN10 limits as one of additional pollutants to the new European emissions regulations, so-called “Euro 7”. As the Consortium for ultra LOw Vehicle Emissions (CLOVE) has proposed, RDE testing by means of PEMS will be the primary means of emissions determination for certification purposes. Measurement equivalency between laboratory-grade emissions measurement systems and PEMS is still important due to the necessity of validation in laboratories before on-road testing by comparing determined emissions by both. The current draft technical requirements for SPN10 measurement in laboratory and on-board allow certain difference in detection efficiencies, especially around the D50 of 10 nm. However, good agreement in the efficiencies between the commercially available laboratory systems and PEMS was observed experimentally by using similar measurement principles based on condensation particle counters (CPCs). The results suggested that the difference in detection efficiencies for the applicable particle size range greater than 10 nm between the laboratory system and PEMS could be within ±10%. Moreover, it is found that the entire system detection efficiencies calibrated directly were equivalent to the calculated efficiencies by individual calibration coefficients of the volatile particle remover and the CPC defined by the regulations.
Gasoline Particulate Filter with Membrane Technology to Achieve the Tight PN Requirement
Authors: Obata Shogo , Furuta Yasuyuki , Ohashi Tatsuya , Aoki Takashi
Published: April 2023

The LDV gasoline emission regulation is set to be tightened for Euro7. In particular, the particulate number (PN) requirement has been significantly tightened requiring a GPF with extra - high filtration efficiency to meet the target requirement.

In order to meet the stricter PN requirements, GPF substrate material improvement is necessary. However, conventional GPF material improvement for high filtration efficiency will increase the filter backpressure significantly. The relationship between pressure drop and CO2 emission is difficult to quantify but high pressure drop can potentially increase the CO2 emission. Therefore, Membrane Technology (MT) is the key to break through the trade-off between filtration performance and pressure drop. MT is thin and dense layer of small grains applied on the GPF surface. MT application can increase particulate filtration efficiency significantly with minimal pressure drop increase. To make MT work effectively, membrane conditions need to be optimized. In addition, the effect of each condition on GPF filtration performance needs to be verified.

On the other hand, it is also important to maintain GPF filtration performance, membrane durability and robustness under all GPF operating conditions and Full Useful Life of the vehicle. In order to achieve the membrane durability and robustness, membrane grains need to be adhered to the GPF surface and GPF performance needs to be evaluated for all GPF operating conditions.

This paper shows the results of membrane technology optimization for maximizing GPF performance, particulate filtration performance of GPF with MT, and the durability performance of MT.
Combustion Experiments of Focusing Engine with Asymmetric Double-Piston System Leading to Relatively-Silent High Compression Ratios
Authors: Naitoh Ken , Kobayashi Tomotaka , Saba Satoshi , Kase Fumiya , Matsuno Ryui , Tanishima Riku , Kawano Keidai
Published: April 2023

In our previous reports, we proposed a new focusing engine with high thermal efficiency based on relatively-silent high compression and nearly-complete air-insulation effect, which employs pulsed multi-jets of gas collided around chamber center. Local compression level due to the gas jets colliding around chamber center before reaction can be varied from zero to 100MPa and 3000K, by changing the number of jets and intake pressure. Relatively-silent high compression is possible, because region around chamber wall is at pressure level of traditional engines. This is suitable for various usages of automobiles, aerocrafts, and rockets, and also for various fuels including hydrogen, because high compression around chamber center leads to stable auto-ignition and potential of low NOx at very lean burning operation.

We developed two types of focusing compression engines, without and with piston. For the new engine without piston, we obtained nearly-complete air-insulation and high thrust. In this report, we show very less occurrence of knocking of gasoline in the engine having strongly-asymmetric double piston system, which leads to potential of braking thermal efficiency over 50% even for small engines.