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Some experimental data indicate that an HCCI process of a highly diluted mixture is characterized with a two-stage profile of heat release after the heat release by low-temperature oxidation, and with slow CO oxidation into CO₂ at a low temperature. In the present paper, these characteristics are discussed using a detailed chemical kinetic model of normal heptane, and based on an authors' idea that an ignition process can be divided into five phases. The H₂O₂ loop reactions mainly contribute to heat release in a low-temperature region of the TI (thermal ignition) preparation phase. However, H+O₂+M=HO₂+M becomes the main contributor to heat release in a high-temperature region of the TI preparation phase. H₂O₂ is accumulated during the LTO (low-temperature oxidation) and NTC (negative temperature oxidation) phases, and drives the H₂O₂ loop reactions to increase the temperature during the TI preparation phase.

The authors have developed a measurement technique using a new digital telemeter which measures the piston secondary motion as ensuring high accuracy while under the operation. We applied this new digital telemeter to several measurements and analysis on the piston secondary motion that can cause piston noises, and here are some of the results from our measurement. We have confirmed that these piston motions vary by only several tenths of millimeter changes of the piston specifications such as the piston-pin offset and the center of gravity of the piston. As in other cases, we have found that a mere change of pressure in the crankcase or the amount of lubricating oil supplied on the cylinder bore varies the piston motion that may give effect on the piston noises.

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.

Engines using natural gas as their main fuel are attracting attention for their environmental protection and energy-saving potential. There is demand for improvement in the thermal efficiency of engines as an energy-saving measure, and research in this area is being actively pursued on spark ignition engines and HCCI engines. In spark ignition gas engines, improving combustion under lean condition and EGR (exhaust gas recirculation) condition is an issue, and many large gas engines use a pre-chamber. The use of the pre-chamber approach allows stable combustion of lean gas mixtures at high charging pressure, and the reduction of NOx emissions. In small gas engines, engine structure prevents the installation of pre-chambers with adequate volume, and it is therefore unlikely that the full benefits of the pre-chamber approach will be derived.

To avoid a trial and error adjustment for designing EMI filters, clarifying load impedance of operating condition, i.e., dynamic impedance of equipment is very useful. Therefore the need to a non-contact measurement method of the impedance connected to a wire harness is increasing rapidly. A measurement method using a network analyzer with two current probes was previously proposed. However, it was confirmed only up to 30 MHz. Many radio equipment operate above 30 MHz such as FM receivers and GPS receivers installed in vehicles. So increasing the measurement frequency is necessary in the auto industry. At first, we tried to expand the applicable frequency to 100 MHz, i.e., FM band. In this study, we applied the transmission line theory using the non-contact measurement method. Furthermore, in order to use the theory, the characteristic impedance and phase constant of the wire harness are required. So we made an additional measurement to estimate them.

Compact, high efficiency and high reliability are required for an xEV motor generator. IPM rotors with neodymium magnets are widely applied for xEV motors to achieve these requirements. However, neodymium magnet material has a big impact on motor cost and there is supply chain risk due to increased usage of these rare earth materials for future automotive xEV’s. On the other hand, a wound-field rotor does not need magnets and can achieve equivalent performance to an IPM rotor. However, brushes are required in order to supply current to the winding coil of the rotor. This may cause insulation issues on xEV motors which utilize high voltage and high currents. Therefore, it is suggested to develop a system which supplies electric energy to the rotor field winding coil from the stator without brushes by applying a transformer between stator coil and rotor field winding. Specifically, add auxiliary magnetic poles between each field winding pole and wind sub-coils to these poles.

Modern vehicles utilize various functionalities that require security solutions such as secure in-vehicle communication and ECU authentication. Cryptographic keys are the basis for such security solutions. We propose two approaches for secure and efficient invehicle key management. In both approaches, an ECU acting as a Key Master in the vehicle is required. The first approach is based on SHE. The Key Master generates and distributes new keys to all ECU based on the SHE key update protocol. The second approach performs key establishment based on key derivation. The Key Master sends a trigger in form of a counter and all ECUs derive new keys based on the received counter value and pre-shared keys. It is thus possible to handle in-vehicle key management without the need for an OEM backend to manage all keys. This reduces cost and complexity of the solution.

We developed a technique to measure oil film pressure distribution in engine main bearings using thin-film pressure sensors. The sensor is 7μm in thickness, and is processed on the surface of an aluminum alloy bearing. In order to increase the durability of the sensor, a layer of MoS2 and polyamide-imide was coated on thin-film sensors. This technique was applied to a 1.4L common-rail diesel engine operated at a maximum speed of 4,500r/min with a 100Nm full load, and the oil film pressure was monitored while the engine was operating. The measured pressure was compared with calculations based on hydrodynamic lubrication (HL) theory.

A new clean diesel combustion concept has been proposed and its excellent performance with respect to gas emissions and fuel economy were demonstrated using a single cylinder diesel engine. It features the following three items: (1) low-penetrating and highly dispersed spray using a specially designed injector with very small and numerous orifices, (2) a lower compression ratio, and (3) drastically restricted in-cylinder flow by means of very low swirl ports and a lip-less shallow dish type piston cavity. Item (1) creates a more homogeneous air-fuel mixture with early fuel injection timings, while preventing wall wetting, i.e., impingement of the spray onto the wall. In other words, this spray is suitable for premixed charge compression ignition (PCCI) operation, and can decrease both nitrogen oxides (NOx) and soot considerably when the utilization range of PCCI is maximized.

In diesel engines with a straight intake port and a lipless cavity to restrict in-cylinder flow, an injector with numerous small-diameter orifices with a narrow angle can be used to create a highly homogeneous air-fuel mixture that, during PCCI combustion, dramatically reduces the NOX and soot without the addition of expensive new devices. To further improve this new combustion concept, this research focused on cooling losses, which are generally thought to account for 16 to 35% of the total energy of the fuel, and approaches to reducing fuel consumption were explored. First, to clarify the proportions of convective heat transfer and radiation in the cooling losses, a Rapid Compression Machine (RCM) was used to measure the local heat flux and radiation to the combustion chamber wall. The results showed that though larger amounts of injected fuel increased the proportion of heat losses from radiation, the primary factor in cooling losses is convective heat transfer.

Instrument clusters that display all information on a TFT-LCD screen, also known as reconfigurable instrument clusters, have become the new trend in automotive interiors. DENSO mass-produced the world's first reconfigurable instrument cluster in 2008. To satisfy customer requirements, large quantities of resources were required. Coupled with an iterative process due to requirement changes, development costs became very high. Reducing development costs was vital in order to expand the reconfigurable instrument cluster products line. One solution was to use existing human machine interface (HMI) tools. However, most HMI tools are geared toward software developers and not graphic artists. Furthermore, each tool has its own unique method for image and scene creation, creating an ineffective and sometimes difficult environment for artists familiar with industry-leading computer graphics (CG) software to learn and use the tools.

To meet the requirements for lower fuel consumption and emissions as well as higher performances, a “Variable Valve Timing - intelligent by Electric motor (VVT-iE)” system has been newly developed. The system has been firstly adopted to the intake valve train of the Toyota's new 4.6 and 5.0 litter V8 SI engine series. The VVT-iE is composed of a cam phasing mechanism connected to the intake camshaft and brushless motor integrated with its intelligent driver. The motor-actuated system is completely free from operating limitation caused from hydraulic conditions. This enjoys an advantage for reducing cold HC. The system also presents further reduction in fuel consumption.

The causes of deaths in traffic accidents are predominantly human factors such as careless or "heedlessness" driving; recently, accidents that are believed to be due to deteriorated physical conditions, such as heart attacks, have been reported. Non-contact electrocardiography (ECG) monitor for continuous ECG detection while driving is needed to reduce a number of fatal accident by human error like this. Recently there are a lot of papers to detect cardiac electricity using capacitance coupling between human body and electrode. This sensor system must be adopted appropriate high input impedance circuit and noise reduction technique as a function of source impedance value especially for a seat mounted sensor.

Humidity sensors used in automatic windshield defogging controls contribute to the improvement of fuel consumption. The optimum control of air conditioning systems can be realized by adding humidity information to conventional systems which have used only temperature information. While resistive humidity sensors have been widely used, their sensing range and responsiveness are observed as issues. Resistive sensors cannot function at a humidity range of around 100% RH as well as at a low temperature range, and have a low response rate to sudden changes in humidity. It is considered that resistive humidity sensors will be replaced with capacitive ones which have a wide sensing range and high responsiveness.

It has been reported that the middle range of gasoline distillation temperatures strongly affects vehicle driveability and exhaust hydrocarbon (HC) emissions, and that MTBE(CH3-O-C4H9)- blended gasoline causes poor driveability during warm-up. The present paper is concerned with the results of subsequent detailed research on gasoline characteristics, exhaust emissions and driveability. In this paper, first it is demonstrated by using four models of passenger cars having different types of exhaust gas treatment system that decreased 50% distillation temperature (T50) reduces exhaust HC emission. This result indicates lowering T50 in the market will contribute to improving air quality. Secondly gasoline behavior in the intake manifold is investigated by using an engine on the dynamometer in order to clarify the mechanisms of HC emission increase and poor engine response which are caused by high T50.

The hole diameter of injection nozzles in diesel engines has become smaller and the nozzle coking could potentially cause injection characteristics and emissions to deteriorate. In this research, engine tests with zinc-added fuels, deposit analyses, laboratory tests and numerical calculations were carried out to clarify the deposit formation mechanisms. In the initial phase of deposit formation, lower zinc carboxylate formed close to the nozzle hole outlet by reactions between zinc in the fuel and lower carboxylic acid in the combustion gas. In the subsequent growth phase, the main component changed to zinc carbonate close to nozzle hole inlet by reactions with CO₂ in the combustion gas. Metal components and combustion gases are essential elements in the composition of these deposits. One way of removing these deposits is to utilize cavitations inside the nozzle holes.

The ignition characteristics of each component of natural gas and the chemical kinetic factors determining those characteristics were investigated using detailed chemical kinetic calculations. Ethane (C2H6) showed a relatively short ignition delay time with high initial temperature; the heat release profile was slow in the early stage of the ignition process and rapid during the late stage. Furthermore, the ignition delay time of C2H6 showed very low dependence on O2 concentration. In the ignition process of C2H6, HO2 is generated effectively by several reaction paths, and H2O2 is generated from HO2 and accumulated with a higher concentration, which promotes the OH formation rate of H2O2 (+ M) = OH + OH (+ M). The ignition characteristics for C2H6 can be explained by H2O2 decomposition governing OH formation at any initial temperature.

The ignition delay times and heat release profiles of CH4, C2H6, C3H8, i-C4H10, and n-C4H10 and dual-component CH4-based blends with these alkanes in air were determined using a detailed chemical kinetic model. The apparent activation energy of C2H6 in the relationship between initial temperature and ignition delay time is higher than those of the other alkanes because OH formation is dominated by H2O2(+M)=OH+OH(+M) from the beginning over a wide range of initial temperatures. The heat release rate of C2H6 is higher than those of the other alkanes in the late stage of ignition delay time because H2O2 is accumulated with a higher concentration and promotes the OH formation rate of H2O2(+M)=OH+OH(+M). These ignition characteristics are reflected in those of CH4/C2H6.

Direct injection gasoline engines require extremely advanced control of air-fuel mixture in order to achieve good stratified combustion. The method of examining quality of mixture formation in combustion chambers is essential for the achievement. In this research, air-fuel mixture in combustion chamber of the TOYOTA D-4 engine was analyzed in space and time by visualization as well as Air/Fuel ratio measurement by multi-point and high response techniques. Thus the effects that injection timing, swirl and fuel pressure exerted to mixture formation were elucidated.

In order to clarify the combustion behavior in the ultra high engine speed range, a new technique has been developed. This technique is composed of ionization current detection and flame observation, and is highly heat-resistant, vibration-resistant, and has a quick response. From analyzing the flame front propagation in the high-speed research engine, it was found that the flame propagated throughout the entire cylinder over almost the same crank angle period irrespective of engine speed introduction.