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Abstract The Formula SAE (FSAE) is an international engineering competition where a Formula style race car is designed and built by students from worldwide universities. According to FSAE regulation, an air restrictor with circular cross section of 20 mm for gasoline-fuelled and 19 mm for E-85-fuelled vehicles is to be incorporated between the throttle valve and engine inlet. The sole purpose of this regulation is to limit the airflow to the engine used. The only sequence allowed is throttle valve, restrictor and engine inlet. A new approach of combining ram theory and acoustic theory methods are investigated to increase the performance of the engine by designing an optimized intake runner for a particular engine speed range and an optimized plenum volume in this range. Engine performance characteristics such as brake power, brake torque and volumetric efficiency are taken into considerations.

Abstract Nitrous oxide (N2O) is both an ozone depleting gas and a potent greenhouse gas (GHG), having a global warming potential (GWP) value nearly 300 times that of carbon dioxide (CO2). While long known to be a trace by-product of combustion, N2O was not considered a pollutant of concern until the introduction of the three-way catalyst (TWC) on light-duty gasoline vehicles in the 1980s. These precious metal-containing catalysts were found to increase N2O emissions substantially. Through extensive research efforts, the effects of catalyst type, temperature, air/fuel ratio, space velocity, and other factors upon N2O emissions became better understood. Although not well documented, N2O emissions from non-catalyst vehicles probably averaged 5-10 mg/mi (on the standard FTP test), while early generation TWC-equipped vehicles exceeded 100 mg/mi. As emissions control systems evolved to meet increasingly stringent criteria pollutant standards, N2O emissions also decreased.

Abstract Continuously tightening Particulate Matter (PM) and Particulate Number (PN) regulations make Gasoline Particulate Filters (GPFs) with high filtration efficiency and low pressure drop highly desirable as Gasoline Direct Injection (GDI) engines increase in market share. Due to packaging constraints, GPFs are often coated with three-way catalyst (TWC) materials to achieve four-way functionality. Therefore, it is critical to investigate the effects of various washcoating strategies on GPF performance. A three-dimensional (3D) Computational Fluid Dynamics (CFD) model, along with an analytical filtration model was created. A User Defined Function (UDF) was implemented to define the heterogeneous properties of the GPF wall due to washcoating or ash membrane application. The model demonstrated the ability to predict transient filtration efficiency and pressure drop of uncoated and washcoated GPFs.

Abstract It has been shown that appropriate regulation of parameters of the gas supply system control algorithm allows to reduce the emission of selected components of the exhaust gas (carbon monoxide [CO], hydrocarbon [HC], and oxides of nitrogen [NOx]). The test engine met the Euro 6 standard on petrol and was equipped with an additional alternative multipoint fuelling system for multipoint injection (MPI) of the gaseous phase liquefied petroleum gas (LPG). The tests are comparative in nature. The first test to compare LPG petrol fuelling was carried out in the New European Driving Cycle (NEDC) where small differences in emissions were shown. The second part of the test compared emissions in the Worldwide harmonized Light vehicles Test Cycle (WLTC), wherein the initial phase there was a significant difference in emissions to the detriment of the gas supply. An innovative approach was therefore proposed to correct settings in the gas system control algorithm.

Abstract Directly injecting fuel in two-stroke spark-ignition (2S-SI) engines will significantly reduce fuel short-circuiting losses. The liquid phase liquefied petroleum gas (LPG) DI (LLDI) mode has not been studied on 2S-SI engines even though this fuel is widely used for transportation. In this experimental work a 2S-SI gasoline-powered engine used on three-wheelers was modified to operate in LLDI mode with an electronic engine controller. The influences of injection pressure (IP), end of injection (EOI) timing, location of the spark plug, and type of injector on performance, combustion, and emissions were studied at different operating conditions. EOI close to bottom dead center with the spark plug located near the exhaust port was the most suitable for the LLDI mode which significantly enhanced the fuel trapping efficiency and improved the thermal efficiency.

Abstract The addition of a spark plug in place of the original fuel injector and fumigating natural gas (NG) inside the intake manifold is an economical way to convert heavy-duty diesel engines to NG spark-ignition (SI) operation. The literature shows that, when compared to a conventional SI engine combustion chamber, the different in-cylinder flow motion, turbulence intensity distribution, and interaction of propagating flame with chamber boundaries in these converted engines produce distinctive combustion stages. As the current understanding of how these combustion stages affect the engine performance is limited, this study used a triple-Wiebe combustion model to determine the effect of spark timing (ST) on the phasing and mass fraction of each combustion stage, at lean operation (ϕ = 0.73) and low engine speed (N = 900 rpm).

Abstract In the development of hydrocarbon (HC) traps for E85 fuel vehicle emission control, the addition of palladium (Pd) to BEA zeolite was studied for trapping and decreasing cold-start ethanol emissions. BEA zeolite after a laboratory aging at 750°C for 25 hours released nearly all of the trapped ethanol as unconverted ethanol at low temperature, and some ethene was released at a higher temperature by a dehydration reaction. The addition of Pd to BEA zeolite showed a decrease in the release of unconverted ethanol emissions even after the lab aging. The release of methane (CH4), acetaldehyde (CH3CHO), carbon monoxide (CO), and CO2 from Pd-BEA zeolite during desorption (temperature programmed desorption (TPD)) demonstrated that multiple ethanol reaction mechanisms were involved including dehydrogenation and decomposition reactions.

Abstract An ongoing challenge with Gasoline engines is achieving rapid activation of the three-way catalyst during cold starts in order to minimize pollutant emissions. Retarded combustion is an effective way in achieving rapid light-up of the three-way catalyst and can be facilitated by stratified charge using late fuel injection. This, however, provides insufficient time for fuel entrainment with air, resulting in locally fuel-rich diffusion combustion. Employing a split injection strategy can help tackle these issues. The effects of a split injection strategy, using a high-pressure Solenoid injector, on the in-cylinder charge formation are investigated in the current study. The studies are performed inside an optical Gasoline engine using high-speed particle image velocimetry (PIV) in the central tumble and Omega tumble planes, by means of a high-speed laser and camera operating at a repetition rate of 10 kHz.

Abstract Uncertainty of fuel reserves, environmental crisis, and health concerns arise from transport demands and reliance on fossil fuels. Downsized gasoline turbocharged direct injection (GTDI) engines have been developed and applied to most modern gasoline vehicles, delivering superior efficiency in high-load operation, reduced friction, and weight. But fuel enrichment and late combustion phasing to mitigate knocking combustion have hindered the efficiency benefits at higher loads with high boost. Furthermore, the wide valve-overlap with a three-cylinder setup for the maximum scavenging efficiency produces bursts of short-circuit (SC) air to cause underestimation of the equivalence ratio by the oxygen sensor, resulting in higher tailpipe nitrogen oxides (NOx) emissions with three-way catalyst (TWC) exhaust aftertreatment. Reducing the valve overlap to limit short-circuiting and enrichment will recover the combustion efficiency and the engine ER, but at the cost of high knock onset.

Abstract The energy management of hybrid electric vehicles (HEVs) is a complex subject that can be addressed with the tools provided by optimal control theory. Optimization algorithms explored so far in the literature, like dynamic programming (DP) or equivalent consumption minimization strategy (ECMS), have systematically analyzed the potential CO2 reduction for different topologies and degree of hybridization. However, the management of engine and electric machine (EM) neglects that the catalyst material in the aftertreatment system needs to reach a certain temperature to properly convert pollutant emissions. In this study, the thermal management of the catalyst in a gasoline HEV has been investigated, and two algorithms have been proposed. Two strategies based on the ECMS are presented: the first one explicitly considers the catalyst temperature; the second one keeps the underlying structure of ECMS, but it adds a high-level rule to indirectly encompass catalyst management.

Abstract Catalytic converters have been effectively controlling the harmful exhaust gases to meet stringent emission norms. This article presents a new three-way catalyst developed using natural zeolite for effective emission reduction. The step-by-step preparation of the material for the developed catalyst is followed by its characterization using an energy dispersive X-ray (EDX), X-ray diffraction (XRD), and scanning electron microscope (SEM). The testing performed on a synthetic gas test bench (SGTB) shows substantial carbon monoxide (CO), hydrocarbon (HC), and nitric oxide (NO) reduction. Results show a 100% conversion for NO above 280°C, 54.8% for CO at 315°C, and 52% for HC at 500°C. The developed natural zeolite-based catalyst stands out from among current catalysts and can be endorsed for three-way conversions than the synthetic zeolite catalyst.

Abstract The impact of technical vehicle conditions on dynamical and emission vehicle characteristics has been of relatively little interest. Therefore, this study focuses on the impact of malfunctions of and unwarranted interferences in the exhaust gas recirculation system, known as EGR, on selected vehicle characteristics. Attention has been paid to the EGR blanking off and its permanent opening, carbon deposition in the engine’s intake manifold, and other malfunctions and interferences commonly occurring during the lifespan of vehicles. The parameters observed have included the composition of the exhaust gases, smoke opacity, engine power and torque, and others. The measurements have been performed with vehicles of different ages, different numbers of kilometers driven, and different levels of engine management.

Abstract In order to meet the emission requirements of the China VI regulations on natural gas (NG) engines, the China VI compliant NG engines generally adopt the equivalent combustion technology route with high-pressure exhaust gas recirculation (HP-EGR). However, the HP-EGR introduction mode heavily relies on engine exhaust pressure, which has negative impact on engine pumping work. In regards to this issue, study on an alternative EGR technology is very important to achieve high EGR introduction ability with low pumping work. In this research, an experimental study on an equivalent-NG engine used in extended-range hybrid vehicles was carried out. The influence of high-low-pressure EGR (HLP-EGR) technology on engine combustion, performance, and emission characteristics was analyzed. The potential of HLP-EGR in improving engine economy and reducing emissions was explored.

Abstract An integrated electrically heated catalyst (EHC) in the three-way catalyst (TWC) of a gasoline internal combustion engine (ICE) is a promising technology to reduce engine cold-start pollutant emissions. Pre-heating the TWC ensures earlier catalyst light-off of a significant portion of the TWC. In such a case, the engine could readily be operated in a fuel-optimal manner since the engine cold-start emission is efficiently treated by the warmed-up EHC-equipped TWC. Pre-heating the EHC is an effective way to reduce cold-start emissions, among other possible EHC strategies. However, it might not always be possible to use pre-heating if the engine-start time is uncertain. In such a case, pre-heating can be started when the engine start is known with greater confidence and post-heating the catalyst could be followed. It would then be natural to turn off the EHC when the payoff for the electrical energy spent is no longer effective in engine cold-start emission reduction.

Abstract Emissions development work for gasoline aftertreatment systems is often conducted in a laboratory on a chassis dynamometer. In this situation, extractive sample lines are frequently connected to the aftertreatment system before and after various components, such as a three-way catalyst, selective catalytic reduction substrate, and the like. This is done to measure the conversion efficiency of the aftertreatment system components as a function of time. The time series exhaust component concentration data, also referred to as continuous data, are combined with a measure of exhaust volumetric flowrate and used to calculate mass-based emissions. As gasoline powertrains become cleaner and produce lower levels of criteria emissions, the proximity (i.e., colocated or not colocated) of the volumetric flowrate and concentration measurements may affect the accuracy of the overall mass emission calculation.

Abstract In urban roads the engine speed and the load vary suddenly and frequently, resulting in increased exhaust emissions. In such operations, the effect of air injection technique to access the transient response of the engine is of great interest. The effectiveness of air injection technique in improving the transient response under speed transient is investigated in detail [1]; however, it is not evaluated for the load transients. Load step demand of the engine is another important event that limits the transient response of the turbocharger. In the present study, response of a heavy-duty turbocharged diesel engine is investigated for different load conditions. Three cases of load transients are considered: constant load, load magnitude variation, and load scheduling. Air injection technique is simulated and after optimization of injection pressure based on orifice diameter, its effect on the transient response is presented.