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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.

DENSO mandated that its 13 affiliated North American facilities implement ISO 14001 by 1999. This posed a number of substantial challenges given the diversity and scope of its operations, challenges which conventional implementation approaches seemed ill-suited to handle. DENSO North America developed and executed a hybrid strategy, “system-consistency,” that may offer valuable lessons for other manufacturers confronting the task of implementing ISO 14001 in a diverse, multi-facility environment. Moreover, “system-consistency” has provided DENSO with tangible economic benefits, including substantial reductions in environmental management systems development, implementation, and re-certification costs that will amount to over $1 million within the first 3 years alone.

In recent years, the powertrain system is becoming bigger and more sophisticated than ever, and it is very important that new powertrain systems shall be timely developed just when the market required. In this kind of new system, the quality in particular will be an important factor on the vehicle evaluation issue. With this objective in mind, DENSO has been working on the following challenges, such as the development of key technology, the improvement of quality assurance system, and engineer education to realize them. This reports a general idea on these quality management activities.

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.

Tightening global emissions standards are driving automotive Original Equipment Manufacturer’s (OEM’s) to utilize Three Way Catalyst (TWC) aftertreatment systems that can perform with greater efficiency and greater measured control of Precious Group Metals (PGM) use. At the same time, TWC aftertreatment systems minimize exhaust system pressure drops. This study will determine the influence of catalyst substrate cell geometry on emission and PGM usage. Additionally, a study of lightoff and backpressure comparisons will be conducted. The two substrate configurations used are hex/750cpsi and square/750cpsi.

In order to comply with emission regulation, reach their profitability targets and minimise the in-use cost of their vehicles, OEMs are seeking solutions to optimise their aftertreatment systems. For Selective Catalytic Reduction (SCR) system engineers, one of the most important challenges is to reduce the system's cost, while keeping its high level of NOx emission reduction performance. Ways to achieve this cost reduction include 1. using an engine out NOx estimation model instead of a NOx sensor upstream of the SDPF (DPF coated with SCR) catalyst and 2. eliminating the Ammonia Slip Catalyst (ASC) downstream of the SDPF catalyst. Achieving these challenging targets requires actions on the complete SCR system, from the optimisation of mixing and uniformity in the SDPF catalyst to the development of robust controls. To face these challenges, a novel exhaust reverse flow concept with a blade mixer was developed.

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.

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.

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.

Exhaust Gas Recirculation (EGR) systems reduce exhaust emissions and improve fuel efficiency. Recently, the number of EGR system installed vehicles has been increasing, especially for gasoline engine systems. One of the major causes of decreasing EGR function is deposit accumulation on a gas passage. The deposit consists mainly of hydrocarbons which are degradation products of fuel, thus the amount of deposit seems to be strongly affected by fuel compositions. Unfortunately there are not as many studies on EGR deposits with gasoline fuel as there are with diesel fuel. In this study, the influence of gasoline fuel compositions, especially aromatics which are major components of EGR gas, on chemical structures of the deposit were investigated. To clarify the accumulation mechanism of EGR deposits, a thermal oxidative degradation test with an autoclave unit and an actual gasoline engine test were employed.

Diesel injection equipment is required to be more accurate and higher in pressure to meet the increasingly strict emission, fuel consumption regulations and higher engine performance. It also needs to achieve a number of requirements such as robustness against diversified market fuels, easy installation to engine, etc.

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.

As automotive electronic systems aiming for a safe and secure automobile society continue to develop, the control specifications of the ECU are becoming increasingly complex. When attempting to validate control specifications that cooperatively control different control specifications, control specification developers must consider various validation viewpoints. They narrow down the validation viewpoints based on rules from past experience, describe timing charts, and validate the specifications. However, due to complicated specifications, empirical rules do not pass, and specification mismatches are often found after actual systems completion. On the other hand, a block diagram simulator is a tool to verify control specifications. Since these tools are aimed at modeling and verifying the system design, it is efficient to describe how to implement the system. However, first it is necessary to verify the consistency between the model and the specifications.

Continuous improvement of gasoline engine emissions performance is required to further protect the global environment and also the impact of emissions on a local level. During real world driving, transient engine operation and variation in fuel injection, airflow, and wall temperature are key factors to be controlled. Due to the limited opportunity for optimization of engine control, generation of a well-mixed fuel spray is necessary to create a suitable combustion environment to minimize emissions. Optimum spray performance achieves minimum surface wetting as well as promoting evaporation and diffusion if wetting occurs. Improvement in spray homogeneity is an important step to achieve this. Higher fuel pressure is initially considered to achieve improvements, as it is expected to improve mixture formation by reduction of wall wetting due to high atomization and lower penetration, as well as improvement in spray homogeneity.

For the purpose of coping with the strengthening of NOx exhaust gas control and fuel consumption control, it is indispensable to improve the NOx purification capacity. In view of this, vehicle manufacturers are in the course of developing high performance SCR (Selective Catalytic Reduction) systems [1, 2]. For such SCR systems to be realized, high precision NOx sensors for carrying out urea injection quantity control and SCR degradation diagnosis are absolutely indispensable. Detection of NOx concentration by means of a NOx sensor is generally performed as follows: O2 is discharged by means of an O2 detection electrode; remaining NOx is decomposed by a NOx detection electrode; NOx concentration is then detected as electric current that flows when oxygen ions are conduct through solid electrolyte. In order to detect NOx of ppm-order, it is necessary to detect minute current of nA-order with high accuracy.

With the economic development of countries around the world led by BRICs(Brazil, Russia, India, China), the total number of automobiles in the world continues to rise. From the standpoint of preserving limited petroleum resources and reducing CO2 emissions, improved fuel consumption is necessary if we are to continue enjoying the use of automobiles. In Europe, significant development of diesel engine technology as a power source for automobiles has taken place to reduce fuel consumption and to enhance the “Fun to Drive” experience, and market share of diesel engines has increased in this area. However, with increasing environmental awareness worldwide, all areas of the globe are seeing tightened regulations for not only fuel consumption, but also exhaust emissions, including those for PM(Particulate Matter) and NOx. Of these regulations, the requirement for vehicles to satisfy the US Tier 2 Bin 5 rating, regardless of whether they are gasoline or dieselpowered, is the most stringent.