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This paper analyzes low-speed pre-ignition (LSPI), a sudden pre-ignition phenomenon that occurs in downsized boosted gasoline engines in low engine speed high-load operation regions. This research visualized the in-cylinder state before the start of LSPI combustion and observed the behavior of particles, which are thought to be the ignition source. The research also analyzed pre-ignition by injecting deposit flakes and other combustible particulate substances into the combustion chamber. The analysis found that these particles require at least two combustion cycles to reach a glowing state that forms an ignition source. As a result, deposits peeling from combustion chamber walls were identified as a new mechanism causing pre-ignition. Additionally, results also suggested that the well-known phenomenon in which the LSPI frequency rises in accordance with greater oil dilution may also be explained by an increase in deposit generation.

This paper evaluates the effect of our new alternator concept for a conventional vehicle, which is able to generate electricity by storing kinetic energy of the vehicle in the high speed flywheel as rotation energy under deceleration. The alternator constructs a planetary gear device and multiple clutch-brakes perform CVT, alternator and high speed flywheel without an expensive electric device, mechanical CVT and vacuum pump. So it has high cost performance.

Higher pressure and higher precision are required for diesel fuel injection equipment in response to increasingly severe emissions control regulations. Market diesel fuels have become more diversified than in the past. Diesel fuel quality has also been changing, being affected by crude oil slate, extreme lowering of sulfur content, and diesel reformulated from heavy fuel oil, among other reasons. As a result of this, deposits thought to have a fuel origin have been observed within diesel fuel injectors in certain regions. Related changes in fuel injection quantity have also been observed. This paper determines injector deposit production mechanisms. It focuses on the structural changes of deposit causative substances by temperature as well as injector design change improvements to prevent deposits.

Fuel cell electric vehicles are a promising technology to create CO2- neutral mobility. Model-based development approaches are key to reduce costs and to raise efficiencies. A model on vehicle system level is discussed that balances the need of physical depth and computational performance. The vehicle model comprises the domains of mechanics, electrics, thermodynamics, cooling and controls. Detailed models of the fuel cell and battery are presented as a part of the system model. The models apply electrochemical approaches and spatial resolutions up to 3D. The models of both components are validated via 3D reference simulations showing a seamless parameter transfer between system level and CFD-based simulations. The validity of the vehicle model, including the electrochemical components, is demonstrated by simulating the Toyota Mirai vehicle. Simulation results of an NEDC are compared to measurements.

The ejector is a fluid pump that recovers expansion energy, which is wasted in the conventional refrigeration cycle decompression process, and converts the recovered expansion energy into pressure energy. In the ejector cycle, the ejector helps to reduce power consumption of the compressor by using the above mentioned pressure-rising effect. Consequently, the ejector system can improve energy efficiency of the refrigeration cycle. In previous work, the ejector cycle was used to reduce power consumption in refrigeration cycles for a cool-box (a beverage cooling inside the vehicle) and refrigerated truck box. Both of these applications used the ejector to achieve refrigerant pressure/temperature below the vehicle cabin temperature. Now, the ejector has been integrated into the vehicle cabin evaporator to reduce power consumption of the refrigeration cycle for vehicle cabin cooling.

Direct injection of gasoline fuel has been gaining on applicability in recent years. Direct injection spark ignited engine has been one of the most investigated designs for achieving lower fuel consumption and for increasing the performance. Maintaining low emissions, decreasing fuel consumption and keeping driving performance are key challenges. Fuel injection quality is one of the most important factors, which directly affect general engine requirements like fuel mass flow, spray penetration and atomization for the combustion process. The multi-hole injector design is a very promising design type for application in direct fuel injection in automotive petrol engines. As a consequence of decreasing supplies of fossil fuels, mixing of different fuel components has become very common in recent years. The type of components which are to be mixed depends on local geographical fuel availability and motorization type.

In recent years, fuel consumption regulations are becoming more severe in every country in the world. Engine size reduction plus turbo is one of the solutions. Our turbo system has an intercooler which cools high temperature gas compressed by a turbocharger. The structure of the intercooler is a tank mounted on both sides of a heat exchanger. The tank connects to the heat exchanger and turbo system allowing EGR (Exhaust Gas Recirculation) gas through the heat exchanger in response to the tightening of exhaust gas regulations. Use of the LPL (Low Pressure Loop) system which refluxes EGR gas is expected to increase from now. Since EGR gas is characterized by high temperature, high pressure, and acidic condensed water, high fatigue strength at high temperature and acid resistivity is required. Therefore aluminum (Al) is generally applied for “intercooler tank” (hereafter referred to as “tank”).

For nearly twenty years, DiMethyl Ether has been known to be an outstanding fuel for combustion in diesel cycle engines. Not only does it have a high Cetane number, it burns absolutely soot free and produces lower NOx exhaust emissions than the equivalent diesel. However, the physical properties of DME such as its low viscosity, lubricity and bulk modulus have negative effects for the fuel injection system, which have both limited the achievable injection pressures to about 500 bar and DME's introduction into the market. To overcome some of these effects, a common rail fuel injection system was adapted to operate with DME and produce injection pressures of up to 1000 bar. To understand the effect of the high injection pressure, tests were carried out using 2D optically accessed nozzles. This allowed the impact of the high vapour pressure of DME on the onset of cavitation in the nozzle hole to be assessed and improve the flow characteristics.

As the demand for improved fuel economy increases and new CO2 regulations have been issued, aerodynamic drag reduction has become more critical. One of the important factors to consider is cooling drag. One way to reduce cooling drag is to decrease the air flow volume through the front grille, but this has an undesirable impact on cooling performance as well as component heat load in the under-hood area. For this reason, cooling drag reduction methods while keeping reliability, cooling performance and component heat management were investigated in this study. At first, air flow volume reduction at high speed was studied, where aerodynamic drag has the greatest influence. For vehicles sold in the USA, cooling specification tends to be determined based on low speed, while towing or driving up mountain roads, and therefore, there may be extra cooling capacity under high speed conditions.

Requirements for fuel economy improvement and reduction in the vehicles engine compartment have increased significantly in the pass years. Performances in radiators have driven changes in terms of compactness and weight reductions. By focusing on the air flow we have optimized the radiator fin and developed a high performance radiator. A similar performance was achieved using an 11mm core depth which has 30% weight reduction compared to a 16mm core depth. The purpose of this paper is to present a technical outline about fin optimization.

Approaching engineering limits for the thermal design of battery modules requires virtual prototyping and appropriate models with respect to physical depth and computational effort. A multi-scale and multi-domain model describes the electrochemical behavior of a single battery unit cell in 1D+1D at the level of intra-cell phenomena, and it applies a 3D thermal model at module level. Both models are connected within a common vehicle simulation platform. The models are discussed with special emphasis on battery degradation such as solid electrolyte interphase layer formation, decomposition and lithium plating. The performance of the electrochemical model is assessed by discharge cycles and repeated charge/discharge simulations. The thermal module model is compared to CFD reference data and studied with respect to its grid sensitivity.

Spark ignited engines are today operated more and more often under high load conditions, where one reason can be identified in the necessity of increasing the efficiency and hence reducing fuel consumption and specific CO2 emissions. Since the gasoline engine operation is inherently limited by knocking at high loads, strategies must be identified, which allow reliable identification and simulation of the appearance of this undesirable type of combustion. A new numerical model for the description of those kinds of pre-flame reactions in a CFD framework is discussed in this paper. Despite emphasis is put here on the auto-ignition effects, it will also be explained that the model is capable of supporting the engine development process in all combustion and emission related aspects.

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.

The demand for better driving comfort, fuel efficiency and reduced CO2 output has been becoming increasingly stringent. In response to such needs, we developed Transmission Electro-Hydraulic Control Module (TEHCM). For Automatic Transmission, expanding the lock-up control area is necessary to improve fuel efficiency. Meanwhile, lock-up control at lower speeds aggravates shift quality. To improve shift quality, Automatic Transmission Fluid (ATF) pressure control must be precise is needed. This can be accomplished by compensating for deviation in TEHCM, which integrates Transmission Control Unit (TCU) and the pressure control actuator, Variable Force Solenoid (VFS). However, there are two problems in installing TEHCM in compact vehicle. The first problem is the miniaturization of such TEHCM. Regarding modules that require a high electrical current to operate the VFS, thermal conductivity contradicts miniaturization.