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To prevent global warming, further reductions in carbon dioxide are required. It is therefore important to promote the spread of electric vehicles powered by internal combustion engines and electric vehicles without internal combustion engines. As a result, emissions from hybrid electric vehicles equipped with internal combustion engines should be further reduced. Interest in catalytic reactions in an electric field with a higher catalytic activity compared to conventional catalysts has increased because this technology consumes less energy than other electrical heating devices. This study was therefore undertaken to apply a catalytic reaction in an electric field to an exhaust emission control. First, the original experimental equipment was built with a high voltage system used to conduct catalytic activity tests.

Premixed charge compression ignition (PCCI) combustion is effective in reducing harmful exhaust gas and improving the fuel consumption of diesel engines [1]. However, PCCI combustion has a problem of exhibiting lower combustion stability than diffusive combustion [2, 3], which makes it challenging to apply to mass production engines. Its low combustion stability problem can be overcome by implementing complicated injection control strategies that account for variations in environmental and engine operating conditions as well as transient engine conditions, such as turbocharging delay, exhaust gas recirculation (EGR) delay, and intake air temperature delay. Although there is an example where the combustion mode is switched according to the intake O2 fraction [4], it requires a significant number of engineering-hours to calibrate multiple combustion modes. And besides, such switching combustion modes tends to have a risk of discontinuous combustion noise and torque.

The recent growth of available computational resources has enabled the automotive industry to utilize unsteady Computational Fluid Dynamics (CFD) for their product development on a regular basis. Over the past years, it has been confirmed that unsteady CFD can accurately simulate the transient flow field around complex geometries. Concerning the aerodynamic properties of road vehicles, the detailed analysis of the transient flow field can help to improve the driving stability. Until now, however, there haven’t been many investigations that successfully identified a specific transient phenomenon from a simulated flow field corresponding to driving stability. This is because the unsteady flow field around a vehicle consists of various time and length scales and is therefore too complex to be analyzed with the same strategies as for steady state results.

Historically, greenhouse gas (GHG) emissions standards for vehicles have focused on tailpipe emissions. However, sound environmental policy requires a more holistic well-to-wheels (WTW) assessment that includes both production of the fuel and its use in the vehicle. The present research explores the net change in WTW GHG emissions associated with moving from regular octane (RO) to high octane (HO) gasoline. It considers both potential increases in refinery emissions from producing HO fuel and potential reductions in vehicle emissions through the use of fuel-efficient engines optimized for such fuel. Three refinery configurations of varying complexity and reforming capacity were studied. A set of simulations covering different levels of HO gasoline production were run for each refinery configuration.

The use of exhaust gas recirculation (EGR) in spark ignition engines has been shown to have a number of beneficial effects under specific operating conditions. These include reducing pumping work under part load conditions, reducing NOx emissions and heat losses by lowering peak combustion temperatures, and by reducing the tendency for engine knock (caused by end-gas autoignition) under certain operating regimes. In this study, the effects of EGR addition on knocking combustion are investigated through a combined experimental and modeling approach. The problem is investigated by considering the effects of individual EGR constituents, such as CO2, N2, and H2O, on knock, both individually and combined, and with and without traces species, such as unburned hydrocarbons and NOx. The effects of engine compression ratio and fuel composition on the effectiveness of knock suppression with EGR addition were also investigated.

For the launch of the redesigned Lexus LS, a new 3.5 L V6 twin turbo engine has been developed aiming at unparalleled performance on four axes, “driving pleasure”, “power-performance”, “quietness” and “fuel economy”. To achieve outstanding power-performance and high thermal efficiency, the specifications have been optimized for high speed combustion. The maximum torque of 600 Nm, power of 310 kW (yielding specific power of 90 kW/L), and the maximum thermal efficiency of 37% have been achieved using several new technologies including a high efficiency turbocharger. A prototype vehicle equipped with this engine and Direct-Shift 10AT achieved a 0-60 mph acceleration time of 4.6 sec, with extremely good CAFE combined fuel economy of 23 mpg and power-performance aligned with V8 turbocharged offerings from competing OEM’s.

In order to adapt to energy security and the changes of global-scale environment, further improvement of fuel economy and adaptation to each country’s severer exhaust gas emission regulation are required in an automotive engine. To achieve higher power performance with lower fuel consumption, the engine’s basic internal design such as an engine block and cylinder head were changed and the combustion speed was dramatically increased. Consequently, stroke-bore ratio and valve layout were optimized. Also, both flow coefficient and intake tumble ratio port were improved by adopting a laser cladded valve seat. In addition, several new technologies were adopted. The Atkinson cycle using a new Electrical VVT (Variable Valve Timing) and new combustion technology adopting new multi-hole type Direct fuel Injector (DI) improved engine power and fuel economy and reduced exhaust emissions.

New 2A/F systems different from usual A/F-O2 systems are being developed to cope with strict regulation of exhaust gas. In the 2A/F systems, 2A/F sensors are equipped in front and rear of a three-way catalyst. The A/F-O2 systems are ideas which use a rear O2 to detect exhaust gas leaked from three-way catalyst early and feed back. On the other hand, the 2A/F systems are ideas which use a rear A/F sensor to detect nearly stoichiometric gas discharged from the three-way catalyst accurately, and to prevent leakage of exhaust gas from the three-way catalyst. Therefore, accurate detection of nearly stoichiometric gas by the rear A/F sensor is the most importrant for the 2A/F systems. In general, the A/F sensors can be classified into two types, so called, one-cell type and two-cell type. Because the one-cell type A/F sensors don’t have hysteresis, they have potential for higher accuracy.

In recent years, from a viewpoint of global warming and energy issues, the need to improve vehicle fuel economy to reduce CO2 emission has become apparent. One of the ways to improve this is to enhance engine thermal efficiency, and for that, automakers have been developing the technologies of high compression ratio and dilute combustion such as exhaust gas recirculation (EGR), and lean combustion. Since excessive dilute combustion causes the failure of flame propagation, combustion promotion by intensifying in-cylinder turbulence has been indispensable. However, instability of flame kernel formation by gas flow fluctuation between combustion cycles is becoming an issue. Therefore, achieving stable flame kernel formation and propagation under a high dilute condition is important technology.

It is important for vehicle concept planning to estimate fuel economy and the influence of vehicle vibration in advance. This can be accomplished using virtual engine specifications and a virtual vehicle frame. In this paper, I will show the power plant model with electric starter and battery that can predict fuel economy, combustion heat results and transient torque. The power plant is a 1.3L 4cyl designed for NA Spark Ignition. The power plant model was realized using an energy based model using VHDL-AMS. Here, VHDL-AMS is modeling language stored in IEC international standard (IEC61691-6) and can realize multi physics in 1D simulation. The modeling language supports electrical, magnetic, thermal, mechanical, fluidic and compressive fluidic domains. The model was created in house using VHDL-AMS and validated on ANSYS SIMPLORER. The simulated results of fuel energy consumption agreed with driving energy and amount of energy losses, e.g. cooling loss, exhaust loss.

Countries and regions around the world are tightening emissions regulations in reaction to the increasing awareness of environmental conservation. At the same time, growing concerns about the depletion of raw materials as vehicle ownership continues to increase is prompting automakers to look for ways of decreasing the use of platinum-group metals (PGMs) in the exhaust systems. This research has developed a new catalyst with strong robustness against fluctuations in the exhaust gas and excellent nitrogen oxide (NOx) conversion performance. This catalyst incorporates rhodium (Rh) clusters with a particle size of several nanometers, and stabilized CeO2-ZrO2 solid-solution (CZ) with a pyrochlore crystal structure as a high-volume oxygen storage capacity (OSC) material with a slow O2 storage rate.

Toyota Motor Corporation is developing a series of engines belonging to its ESTEC (Economy with Superior Thermal Efficient Combustion) development concept. This paper describes the development of 8NR-FTS after the subsequent launch of the 2.0-liter DI Turbocharged 8AR-FTS. 8NR-FTS is a 1.2-liter inline 4-cylinder spark ignition downsized turbocharged direct injection (DI) gasoline engine. By following the same basic concepts as 8AR-FTS engine [1], the 8NR-FTS incorporates various fuel efficient technologies such as a cylinder head with an integrated exhaust manifold, the Atkinson cycle using the center-spooled variable valve timing with mid-position lock system (VVT-iW), and intensified in-cylinder turbulence to achieve high-speed combustion.

In recent years, enhancing engine thermal efficiency is strongly required. Since the maximum engine thermal efficiency is especially important for HVs, the technologies for improving engine thermal efficiency have been developed. The current gasoline engines for hybrid vehicles have Atkinson cycle with high expansion ratio and cooled exhaust gas recirculation (EGR) system. These technologies contribute to raise the brake engine thermal efficiency to more than 38%.In the near future the consumers demand will push the limit to 40% thermal efficiency. To enhance engine thermal efficiency, it is essential to improve the engine anti-knock quality and to decrease the engine cooling heat loss. To comply with improving the anti-knock quality and decreasing the cooling heat loss, it is known that the cooled EGR is an effective way.

Improving the engine efficiency to respond to climate change and energy security issues is strongly required. In order to improve the engine efficiency, lower fuel consumption, and enhance engine performance, OEMs have been developing high compression ratio engines and downsized turbocharged engines. However, higher compression ratio and turbocharging cause cylinder pressure to increase, which in turn increases the demand voltage for ignition. To reduce the demand voltage, a new ignition system is developed that uses a high voltage Zener diode to maintain a constant output voltage. Maintaining a constant voltage higher than the static breakdown voltage helps limit the amount of overshoot produced during the spark event. This allows discharge to occur at a lower demand voltage than with conventional spark ignition systems. The results show that the maximum reduction in demand voltage is 3.5 kV when the engine is operated at 2800 rpm and 2.6 MPa break mean effective pressure.

This paper presents the effects of a lubricant oil droplet on the start of combustion of a fuel-air mixture. Lubricant oil is thought to be a major source of low-speed pre-ignition in highly boosted spark ignition engines. However, the phenomenon has not yet been fully understood because its unpredictability and the complexity of the mixture in the engine cylinder make analysis difficult. In this study, a single oil droplet in a combustion cylinder was considered as a means of simplifying the phenomenon. The conditions under which a single oil droplet ignites earlier than the fuel-air mixture were investigated. Tests were conducted by using a rapid compression expansion machine. A single oil droplet was introduced into the cylinder through an injector developed for this study. The ignition and the flame propagation were observed through an optical window, using a high-speed video camera.

Gasoline engine downsizing combined with a turbocharger is one of the more effective approaches to improve fuel efficiency without sacrificing power performance. The benefit comes from lower pumping loss, lower mechanical friction due to ‘downsizing’ of the engine displacement and ‘down-speeding’ of the engine by using higher transmission gear ratios which is allowed by the higher engine torque at lower engine speeds. However abnormal combustion referred to as Low-Speed Pre-ignition (LSPI) is known to be able to occur in low-speed and high-torque conditions. It is a potential restriction to maximize the engine performance and its benefit, therefore prevention of LSPI is strongly desired for long-term durability of engine performance. According to recent technical reports, auto-ignition of an engine oil droplet in a combustion chamber is believed to be one of major contributing factors of LSPI and its formulations have a significant effect on LSPI frequency.

This paper focuses on the fuel contribution to crankcase engine oil degradation in gasoline fueled engines in view of insoluble formation. The polymerization of degraded fuel is responsible for the formation of insoluble which is considered as a possible cause of low temperature sludge in severe vehicle operating conditions. The main objective of the study is to understand the mechanism of formation of partially oxidized compounds from fuel during the combustion process, before their accumulation in the crankcase oil. A numerical method has been established to calculate the formation of partially oxidized compounds in spark ignition engines directly, by using 3D CFD. To further enable the possibility of running a large number of simulations with a realistic turn-around time, a coupled approach of 3D CFD (with simplified chemical mechanism) and 0D Kinetics (with full chemical mechanism) is proposed here.

At the engine restart, when the temperature of the catalytic converter is low, additional fuel consumption would be required to warm up the catalyst for controlling exhaust emission.The aim of this study is to find a thermally optimal way to reduce fuel consumption for the catalyst warm up at the engine restart, by improving the thermal retention of the catalytic converter in the cool down process after the previous trip. To make analysis of the thermal flow around the catalytic converter, a 2-D thermal flow model was constructed using the thermal network method. This model simulates the following processes: 1) heat conduction between the substrate and the stainless steel case, 2) heat convection between the stainless steel case and the ambient air, 3) heat convection between the substrate and the gas inside the substrate, 4) heat generation due to chemical reactions.

The advantages of gasoline direct-injection are intake air cooling due to fuel vaporization which reduces knocking, additional degrees of freedom in designing a stratified injection mixture, and capability for retarded ignition timing which shortens catalyst light-off time. Stratified mixture combustion designs often require complicated piston shapes which disturb the fluid flow in the cylinder, leading to power reduction, especially in turbocharged gasoline direct-injection engines. Our research replaced the conventional shell-type shallow cavity piston with a dog dish-type curved piston that includes a small lip to facilitate stratification and minimize flow disturbance. As a result, stable stratified combustion and increased power were both achieved.

ExxonMobil, Corning and Toyota have collaborated on an Onboard Separation System (OBS) to improve gasoline engine efficiency and performance. OBS is a membrane based process that separates gasoline into higher and lower octane fractions, allowing optimal use of fuel components based on engine requirements. The novel polymer-ceramic composite monolith membrane has been demonstrated to be stable to E10 gasoline, while typically providing 20% yield of ∼100 RON product when using RUL 92 RON gasoline. The OBS system makes use of wasted exhaust energy to effect the fuel separation and provides a simple and reliable means for managing the separated fuels that has been demonstrated using several generations of dual fuel test vehicles. Potential applications include downsizing to increase fuel economy by ∼10% while maintaining performance, and with turbocharging to improve knock resistance.