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Combustion-pressure-data-based feedback control of fuel injection and EGR is the most promising diesel system, since it can reduce fuel consumption and emissions, as well as noise and vibration, and improve the evaluation efficiency for adapting engine performance to. We developed a combustion pressure sensor installed inside the glow plug. This is superior in maintainability and ease of installation, and can detect the combustion pressure in each cylinder at high accuracy and low cost, with no need for engine modification.

As vehicle emission regulations become increasingly rigorous, the automotive industry is accelerating the development of electrified vehicle platforms such as Battery Electric Vehicles (BEV) and Plug-in Hybrid Electric Vehicles (PHEV). Since the available waste heat from these vehicles is limited, additional heat sources such as electric heaters are needed for cabin heating operation. The use of a heat pump system is one of the solutions to improve EV driving range at cold ambient conditions. In this study, an efficient gas-injection heat pump system has been developed, which achieves high cabin heating performance at low ambient temperature and dehumidification operation without the assistance of electric heaters in ’17 model year Prius Prime.

The coming Diesel powertrains will remain as key technology in Europe to achieve the stringent 2025 CO2 emission targets. Especially for applications which are unlikely to be powered by pure EV technology like Light Duty vehicles and C/D segment vehicles which require a long driving range this is the case. To cope with these low CO2 targets the amount of electrification e.g. in form of 48V Belt-driven integrated Starter Generator (BSG) systems will increase. On the other hand the efficiency of the Diesel engine will increase which will result in lower exhaust gas temperatures resulting in a challenge to keep the required NOx reduction system efficiencies under Real Drive Emissions (RDE) driving conditions. In order to comply with the RDE legislation down to -7 °C ambient an efficient thermal management is one potential approach. Commonly utilized means to increase exhaust gas temperature are late injection and/or intake throttling, which enable sufficient NOx reduction efficiency.

In respect to the present large refrigerator trucks, sub-engine type is the main product, but the basic structure does not change greatly since the introduction for around 50 years. A sub-engine type uses an industrial engine to drive the compressor, and the environmental correspondence such as the fuel consumption, the emission is late remarkably. In addition, most of trucks carry the truck equipment including the refrigerator which consumes fuel about 20% of whole vehicle. Focusing on this point, the following are the reports about the system development plan for fuel consumption reduction of the large size refrigerator truck. New concept is to utilize electrical power from HV system to power the electric-driven refrigerator. We have developed a fully electric-driven refrigerator system, which uses regenerated energy that is dedicated for our refrigerator system.

In the future, autonomous vehicles will be realized. It is assumed that traffic accidents will be caused by the overconfidence to the autonomous driving system and the lack of communication between the vehicle and the pedestrian. We propose that one of the solutions is a display system to give the information the state of vehicle to pedestrians. In this paper, we studied how the information influences the motion of pedestrians. The vehicle gives the information, which is displayed on road by using of color light (red, yellow and blue), of the collision risk determined by the TTC (Time to Collision). The pedestrian is ordered to cross the road in several cases of the TTC. In the presence of the TTC information, the number of the pedestrians, who did not cross the road in the case of short TTC (red light is displayed), increased from 52% to 67%. It is cleared that the pedestrians determined whether they crossed the road or not by the information effectively.

A methodology for simulating effect of international variations in fuel compositions on spray combustion is proposed. The methodology is validated with spray combustion experiments with real fuels from three different countries. The compositions of those fuels were analyzed through GC×GC and H-NMR. It was found that ignition delay times, flame region and flame luminosity were significantly affected by the compositional variations. For the simulation, an evaporation surrogate consisting of twenty two species, covering basic molecular types and a wide range of carbon numbers, is developed. Each species in the evaporation surrogate is then virtually converted to a reaction surrogate consisting of n-hexadecane, methylcyclohexane and 1,2,4-trimethyl benzene so that combustion reactions can be calculated with a published kinetic model. The virtual species conversion (VSC) is made so as to take over combustion-related properties of each species of evaporation surrogates.

Diesel common rail injectors are required to utilize a higher injection pressure and to achieve higher injection accuracy in order to meet increasingly severe emissions, less fuel consumption, and higher engine performance demand. In addition to those requirements, in conjunction with optimized nozzle geometry, a more rectangular injection rate and stable multiple injections with shorter intervals are required for further emissions and engine performance improvement by optimizing the combustion efficiency.

In automobiles, Integrated Starter Generators (ISGs) are important components since they ensure significant fuel economy improvements. With motors that operate at high voltage such as ISGs, it is important to accurately know partial discharge inception voltages (PDIVs) for the assured insulation reliability of the motors. However, the PDIVs vary due to various factors including the environment (temperature, atmospheric pressure and humidity), materials (water absorption and degradation) and voltage waveforms. Consequently, it is not easy either empirically or analytically to ascertain the PDIVs in a complex environment (involving, for example, high temperature, low atmospheric pressure and high humidity) in which many factors vary simultaneously, as with invehicle environments. As a well-known method, PDIVs can be analyzed in terms of two voltage values, which are the breakdown voltage of the air (called “Paschen curve”) and the shared voltage of the air layer.

Reducing the loss of the power control unit (PCU) in a hybrid vehicle (HV) is an important part of improving HV fuel efficiency. Furthermore the loss of power devices (insulated gate bipolar transistors (IGBTs) and diodes) used in the PCU must be reduced since this amounts to approximately 20% of the total electrical loss in an HV. One of the issues for reducing loss is the trade-off relationship with reducing voltage surge. To restrict voltage surge, it is necessary to slow down the switching speed of the IGBT. In contrast, the loss reduction requires the high speed switching. One widely known method to improve this trade-off relationship is to increase the gate voltage in two stages. However, accurate and high-speed operation of the IGBT gate control circuit is difficult to accomplish. This research clarifies a better condition of the two-stage control and designed a circuit that improves this trade-off relationship by increasing the speed of feedback control.

For the purpose of improving vehicle fuel efficiency, it is necessary to reduce energy loss in the alternator. We have lowered the resistance of the rectifying device and connecting components, and control the rectifying device with an IC to reduce rectification loss. For the package design, we have changed the structure of the part on which the rectifying device is mounted into a high heat dissipation type. The new structure has enabled optimizing the size of the rectifying device, resulting in the reduction of size of the package. In addition, the rectifying device is mounted using a new soldering material and a new process, which has improved the reliability of the connection. Moreover, since the alternator has introduced a new system, the controller IC has a function for preventing malfunction of the rectifying device and a function for detecting abnormalities, in order to ensure safety.

Alternator, which supplies electric energy to a battery and electrical loads when it is rotated by engine via belt, is one of key components to improve vehicle fuel efficiency. We have reduced rectification loss from AC to DC with a MOSFET instead of a rectifier diode. It is important to turn on the MOSFET and off during a rectification period, called synchronous control, to avoid a current flow in the reverse direction from the battery. We turn it off so as to remain a certain conduction period through a body diode of the MOSFET before the rectification end. It is controlled by making a feedback process to coincide with an internal target conduction period based on the rotational speed of the alternator. We reduced a voltage surge risk at turn-off by changing the feedback gain depending on the sign of the time difference between the measured period and the target.

Recent electric vehicles use Li-ion batteries to power the main electric motor. To maintain the safety of the main electric motor battery using Li-ion cells, it is necessary to monitor the voltage of each cell. DENSO has developed a battery Electronic Control Unit (ECU) that contributes greatly to the reduction of the cost and the improvement of the reliability of the system. Each manufacturer has been developing a dedicated IC for monitoring the voltages of each cell of a battery. However, since the number of cells that can be monitored is limited, more than one IC is required to measure the voltages of a large number of cells. The increase in the number of ICs and the amount of insulator leads to the rise in system cost. DENSO has developed a dedicated IC that uses a proprietary high-breakdown voltage process, and which enables monitoring up to 24 cells with a single IC chip.

In-vehicle network communication is evolving faster speeds and higher performance capabilities, connecting the information possessed by ECU and sensors with the in-vehicle electronic systems which are continuing to develop. With the evolution of the complicated networks, it is becoming difficult to develop them without many verification of actual machine. On the other hand, as for the verification means required at the logic level or physical level for a network verification through ECU design, virtual verification in the whole vehicle is difficult due to speed increases and the sheer size of the system. Therefore, it is only applicable for systems which are limited to a domain or an area, and flexible and timely utilization would be difficult due to the changes in specifications.

The Diesel engine performance was drastically improved since the introduction of the Common Rail system in 1996. Over the years, the Common Rail technology was continuously improved to reduce the fuel consumption, engine-out emissions and enhance the drivability. However further technical improvement steps for a precise control of combustion are required to satisfy the increasing stringent worldwide emissions limits and to contribute to attractively performing Diesel powered vehicles. Common Rail injectors significantly contribute to improve the combustion. This improvement can be achieved by precisely controlling the injected fuel quantity and increasing the injection pressure. In addition to those features, a more rectangular injection rate, the capability of stable multiple injections at shorter intervals and the control of the spray shape, are required to achieve an optimized fuel mixture.

Gasoline direct injection (GDI) systems are a main development focus for global environment issues and energy security. At the same time, it is also important to challenge further development of Multi point injection (MPI) systems for a simple and robust combustion system responding to global fuels ,required for the growing automotive markets in emerging countries, especially in the A, B vehicle segments. This paper focuses on reducing wall wetting in cold conditions and maximizing mixture cooling by fuel vaporization (preventing knocking) in high load conditions as key development points of MPI systems. We propose a dual MPI system enhancing direct flow of spray into the combustion chamber to gain part of the benefit of GDI in addition to the homogeneity advantage of an MPI system. This dual MPI system requires finer atomization with at the same time robustness against intake airflow.

This paper describes the reliability of silicon carbide (SiC) MOSFET. We clarified the relation between the lifetime of the gate oxide and the crystal defects. We fabricated MOS diodes using thermal oxidation and measured their lifetimes by TDDB (Time Dependent Dielectric Breakdown) measurement. The wear-out lifetime is sufficient for hybrid vehicle but many MOS diodes broke in shorter time. The breakdown points were defined by Photo-emission method. Finally, we classified the defects by TEM (Transmission Electron Microscopy). A TSD (Threading Screw Dislocation) plays the most important role in the lifetime degradation of the gate oxide. The lifetime of the gate oxide area, in which a TSD is included, is shorter by two orders of magnitude than a wear-out breakdown. The mechanism by which threading dislocations degrade the gate oxide lifetime was not discovered. To explain the degradation, we assumed two models, the shape effect and the oxide quality degradation.

Recently, diesel engine manufacturers have been improving the tolerance of fuel injection quantity and timing in response to the strengthening of emissions regulations and the introduction of various kinds of diesel fuels. This paper describes the Intelligent Accuracy Refinement Technology (i-ART) system, which has been developed as a way of achieving substantially improved tolerances. The i-ART system consists of a fuel pressure sensor installed in the injectors. It calculates the injection quantity and timing at high speed using a dedicated microcomputer designed for pressure waveform analysis. As the injector can directly measure the fuel injection pressure waveform for each injection, it can compensate the injection quantity and timing tolerance at any time. Toyota Motor Corporation has introduced this system in Brazilian market vehicles. In Brazil, the PROCONVE L6 emissions regulations will be introduced in 2012, and the market also uses various kinds of diesel fuels.

To comply with increasing fuel efficiency regulations, a low temperature radiator (LT radiator) is required to cool the charge-air system of a turbocharged engine. These engines are important to use for environmentally-friendly cars. Since heavy-duty and high-performance cars demand high cooling performance, the main radiator alone is typically insufficient in meeting the vehicle’s cooling requirements. An additional radiator installed in the front of the wheel-well is required to meet the extra cooling demand. In order to install this radiator in the front of the wheel-well, guaranteed performance in the limited packaging space and impact resistance of the leading tube edge are required. We developed the Supplementary Inner-Fin Radiator (SIR) which achieves the compact, high-performance, and durability requirements by use of an inner-fin tube (I/F tube). The purpose of this paper is to report our design approach and product specifications of the SIR.

Electronics has greatly contributed to the operation of internal combustion engines. This is especially evident in the benefits that it has brought to drivers, such as enhancing the “Fun to Drive” experience and in reducing the cost of fuel. Moreover, this progress has resulted in minimizing environmental degradation, and yet continuing to support improvements in performance. In the diesel engine, which has superb fuel economy, the innovative progress has been achieved by the common rail technology. The common rail system has the features of high injection pressure control in all engine speed range, highly precise injection control and multiple injections per combustion cycle. The latest 2nd generation of the DENSO common rail system features 1800 bar injection pressure, and five times multiple injection with fully electronic control to ensure precise small injection quantities. This technology has been commercialized into passenger car products in the European market.

In SI engines with port injection system, the injected fuel spray adheres surely on the port wall and the inlet valve, consequently, the spray-wall interaction process leads to the generation of unburned hydrocarbons and uncontrollable mixture formation. This paper deals with the fuel mixture preparation process including basic research on characteristics of the wall-wetted fuel film on a flat wall inside a constant volume vessel. In the experiments, iso-octane mixed with biacetyl as a tracer dopant was injected through a pintle type injector against a flat glass wall under the ambient conditions of atmospheric pressure and room temperature. The thickness of the adhered fuel film on the wall was quantitatively measured by using laser induced fluorescence (LIF) technique, which provides 2-D distribution information with high special resolution as a function of the injection duration, the impingement distance from the injector to the wall, and the impingement angle against the wall.