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The development of electric vehicles has been progressed, rapidly, to achieve Carbon neutrality by 2050. There have been increasing concerns about Electromagnetic Compatibility (EMC) performance due to increasing power for power trains of vehicles. Because same power train system expands to some vehicles, we have developed numerical simulations in order to predict the vehicle EMC performances. We modeled a vehicle which has inverter noises by numerical simulation to calculate electric fields based on GB/T18387. We simulated the common mode noise which flows through the shielding braid of the high voltage wire harnesses. As a result, it is confirmed a correlation between the electric fields calculated by numerical simulation and the measured one.

This paper presents a design method for continuous fiber composites in three-dimensional space with locally varying orientation distribution and their fabrication method. The design method is formulated based on topology optimization by augmented tensor field design variables. The fabrication method is based on Tailored Fiber Placement technology, whereby a CNC embroidery machine prepares the preform. The fiber path is generated from an optimized orientation distribution field. The preform is formed with vacuum-assisted resin transfer molding. The fabricated prototype weighs 120 g, a 70% weight reduction, achieving 3.5× mass-specific stiffness improvement.

Wireless Power Transfer (WPT) promises automated and highly efficient charging of electric and plug-in-hybrid vehicles. As commercial development proceeds forward, the technical challenges of efficiency, interoperability, interference and safety are a primary focus for this industry. The SAE Vehicle Wireless Power and Alignment Taskforce published the Recommended Practice J2954 to help harmonize the first phase of high-power WPT technology development. SAE J2954 uses a performance-based approach to standardizing WPT by specifying ground and vehicle assembly coils to be used in a test stand (per Z-class) to validate performance, interoperability and safety. The main goal of this SAE J2954 bench testing campaign was to prove interoperability between WPT systems utilizing different coil magnetic topologies. This type of testing had not been done before on such a scale with real automaker and supplier systems.

This research developed a new measurement technology for thermal analysis of the heat radiation from a hybrid transaxle case surface to the air and improved the heat radiation performance. This heat flux measurement technology provides the method to measure heat flux without wiring of sensors. The method does not have effects of wiring on the temperature field and the flow field unlike the conventional methods. Therefore, multipoint measurement of heat flux on the case surface was enabled, and the distribution of heat flux was quantified. To measure heat flux, thermal resistances made of plastic plates were attached to the case surface and the infrared thermography was used for the temperature measurement. The preliminary examination was performed to confirm the accuracy of the thermal evaluation through heat flux measurement. The oil in the transaxle was heated and the amount of heat radiation from the case surface was measured.

The Rx400h, which was put on the market in 2005, realized overwhelming power performance with the adoption of a high-voltage system, high-power output motor, and 3-motor type 4WD. Toyota has been working on a solution to increase the output power of the motor, i.e., the development of system stabilization technology. This paper introduces high-speed power balance control, which keeps the balance of power constant regardless of rapid changes in the number of motor rotations resulting from slipping tires or other factors, along with sensor error compensation control, which suppresses cyclic power fluctuation resulting from errors in the position sensor of the motor.

In order to help avoid or mitigate rear-end collisions a Pre-Collision System (PCS) was developed. The purpose of this study is to clarify the Time-to-Collision (TTC) distribution when approaching a lead vehicle under normal driving condition. To enhance the effectiveness of PCS, warnings and/or automatic brake activation should happen as early as possible, however, if too early there is a high possibility of false warnings or activations, which is not desirable. If the distribution of distance to a lead vehicle under normal driving conditions is quantified, an approach limit can be estimated. In this study, we try to clarify a TTC distribution that is approximated by a log-normal distribution. Then, we investigate the Enhanced Time-to-Collision (ETTC) that is the secondary predictive value of TTC. And, we clarify the log-normal distribution of ETTC is a more stable approximator of normal driving than a log-normal distribution of TTC.

This study aims at the development of a projection pattern that is capable of shortening the time required by a driver to perceive a pedestrian at night when a vehicle’s high beams are utilized. Our approach is based on the spatio-temporal frequency characteristics of human vision. Visual contrast sensitivity is dependent on spatiotemporal frequency, and maximum contrast sensitivity frequency varies depending on environmental luminance. Conventionally, there are several applications that utilize the spatio-temporal frequency characteristics of human vision. For example, the National Television System Committee (NTSC) television format takes into consideration low-sensitivity visual characteristics. In contrast, our approach utilizes high-sensitivity visual characteristics based on the assumption that the higher contrast sensitivity of spatio-temporal frequencies will correlate more effectively with shorter perception times.

In recent vehicles, E/E architecture is defined and used as a platform to accommodate various electronics features for better development efficiency, lower cost and higher quality. As electronics features increase and integrated control systems make vehicle electronics more complex, good electronics platforms are vital for today's and future vehicle development. This paper first describes the evolution of vehicle electronics and its recent trend and then addresses the challenges facing vehicle electronics: ✓ More integrated control systems ✓ More software ✓ More networks ✓ Shorter time to market Finally, why JasPar1), Japan Automotive Software Platform and Architecture, was founded and how it is organized will be described including the working group activities on FlexRay implementation.

The basic goals of privacy and authenticity of personal data are summarized, and examples of potential threats to privacy in telematics applications are provided. Probable telematic transactions for the automotive environment are analyzed for typical versus necessary personal content. The question of privacy versus confidentiality versus security versus authenticity is discussed in the context of system design and service provider responsibilities. Several examples of how current telematic systems address privacy are provided, and worldwide trends in architectures followed the "designed in privacy" concept are briefly described.

Crosscheck tests of fast electrical mobility spectrometers, Differential Mobility Spectroscopy (DMS) and Engine Exhaust Particle Sizer(EEPS), were conducted to evaluate the accuracy of fine particle measurement. Two kinds of particles were used as test particles for the crosscheck test of instruments: particles emitted from diesel vehicles and diluted in a full dilution tunnel, and particles generated by CAST. In the steady state tests, it was confirmed that the average concentration of each instrument was within the range of ±2σ from the average concentration of all the same type of instruments. In the transient tests, it is verified that the instruments have almost equal sensitivity. For application of the fast electrical mobility spectrometers to evaluation of particle number and size distributions, it is essential to develop a calibration method using reference particle counters and sizers (CPC, SMPS, etc.) and maintenance methods appropriate for each model.

Vehicles equipped with in-wheel motors (IWMs) are capable of independent control of the driving force at each wheel. These vehicles can also control the motion of the sprung mass by driving force distribution using the suspension reaction force generated by IWM drive. However, one disadvantage of IWMs is an increase in unsprung mass. This has the effect of increasing vibrations in the 4 to 8 Hz range, which is reported to be uncomfortable to vehicle occupants, thereby reducing ride comfort. This research aimed to improve ride comfort through driving force control. Skyhook damper control is a typical ride comfort control method. Although this control is generally capable of reducing vibration around the resonance frequency of the sprung mass, it also has the trade-off effect of worsening vibration in the targeted mid-frequency 4 to 8 Hz range. This research aimed to improve mid-frequency vibration by identifying the cause of this adverse effect through the equations of motion.

It is difficult to improve tire cavity noise since the pressure of cavity resonance acts as a compelling force, and its low damping and high gain characteristics dominate the vibration of both the suspension and body. For this reason, the analysis described in this article aimed to clarify the design factors involved and to improve this phenomenon at the source. This was accomplished by investigating the acoustic coupling vibration mode of the wheel, which is the component that transmits the pressure of cavity resonance at first. In addition, the vibration characteristic of suspension was investigated also. A speaker-equipped sound pressure generator inside the tire and wheel assembly was developed and used to infer that wheel vibration under cavity resonance is a forced vibration mode with respect to the cavity resonance pressure distribution, not an eigenvalue mode, and this phenomenon may therefore be improved by optimizing the out-of-plane torsional stiffness of the disk.

Electric vehicles (EVs) are attracting attention due to growing awareness of environmental issues such as fossil fuel depletion and global warming. In particular, a wide range of research has examined how direct yaw moment controls (DYCs) can enhance the handling performance of EVs equipped with multiple in-wheel motors (IWMs) or the like. Recently, this research has focused on reducing energy consumption through driving force distribution control. The first report proposed a method to minimize energy consumption through an efficient DYC for extending the cruising range of a vehicle installed with four IWMs, and described the vehicle behavior with this control. Since motors allow high design flexibility, EVs can be developed with a variety of drive systems. For this reason, various driving force distribution control methods can be considered based on the adopted system.

Hydrotreated Vegetable Oil (HVO) and Sugar-to-Diesel as next-generation bio diesel fuels consist of normal and iso-paraffin, and those carbon number of paraffinic hydrocarbons and distillation characteristics are narrow distribution. These characteristics would cause to deteriorate the evaporation and mixture with air and fuel. Therefore, in this study, the effects of normal paraffin (Tridecane) and iso-paraffin (HVO) on emission characteristics and cold start performance in a diesel engine were investigated by engine dynamometer tests, cold start vehicle tests, and spray analyzer tests. From the results, it was found that normal and iso-paraffin are beneficial for HC, CO, Smoke emission reduction. In addition, isomerization is effective for the diesel engine to fulfill cold start performance, since normal paraffin of narrow carbon number distribution became solidified under low temperature and high pressure condition in a common rail system.

TOYOTA has developed the iQ with a 1.3L engine for the Scion brand in USA. Due to the importance of fun-to-drive factor for the Scion brand image, a responsive driving performance is required even with compact packaging and a small engine. In addition, because of the recent attention to global-warming and energy issues on a global scale, development of vehicles with high fuel economy is one of the most important issues for a car manufacturer. Therefore, it is necessary for a vehicle to have both high driving performance and fuel economy. TOYOTA has adopted the CVT-i as the transmission for this purpose. The following were achieved by adopting the CVT-i as the transmission for the iQ(1.3L). 1 Responsive driving performance with shift changes without a time lag. 2 Compact transmission for efficient vehicle packaging 3 Class-leading fuel economy performance. Moreover, it was developed with adjustments for the US market by improving the shift schedule for a linear acceleration feel.

The GS450h requires higher system voltage to increase the motor output. For the insulated gate bipolar transistor (IGBT) that serves as the built-in switching device in the intelligent power module (IPM), higher voltage means greater loss and a larger device surface area, and it can also reduce the vehicle's fuel economy performance and increase its cost. To solve these issues, IGBT losses were reduced by (1) using a trench structure to make the IGBT more compact and (2) using a new structure in which the concentration of impurities in the drift layer is optimized. As a result, the device surface area was reduced by 10%, losses were reduced by 14%, and improved vehicle performance was achieved.

Silver metallic colors with thin and smooth aluminum flake pigments have been introduced for luxury brand OEMs. Regarding the paint formulation for these types of colors, low non-volatile(NV) and high aluminum flake pigment contents are known as technology for high metallic appearance designs. However, there are two technical concerns. First is mottling which is caused by uneven distribution of the aluminum flake pigments in paint film and second is poor film property due to high aluminum pigment concentration in paint film. Therefore, current paint systems have limitation of paint design. As a countermeasure for those two concerns, we had investigated cellulose nanofiber (CNF) dispersion liquid as both the coating binder and rheology control agent in a new type of waterborne paint system. CNF is an effective rheology control agent because it has strong hydrogen bonds with other fiber surfaces in waterborne paint.

Automobile manufacturers have increased the pace of vehicle development in recent years to respond to diverse market demands. Consequently, it has become crucial for manufacturers to develop new technology which enables a particular vehicle to simultaneously achieve both ride comfort and handling performance at an optimal level. This article introduces the suspension design technology applying the Principal Elastic Axes that has been developed by our company for use in its vehicles. These axes, which consist of three translational and three rotational axes, represent the set of fully decoupled stiffness axes. Applying the Principal Elastic Axes to the suspension reduces the number of design parameters, which enables suspension movements to be considered totally and simply.

Toyota Motor Corporation began leasing a new generation fuel cell vehicle the FCHV (Fuel Cell Hybrid Vehicle) in December 2002. That vehicle includes a new variable voltage power electronics system and uses the Nickel Metal Hydride (Ni-MH) battery system from the Prius hybrid gasoline electric vehicle. This paper describes on-going efforts to model optimum secondary storage systems for future vehicles. Efficiency modeling is presented for the base Ni-MH storage system, an ultra capacitor system and a Lithium ion (Li-ion) battery system. The Li-ion system in combination with a new high efficiency converter shows a 4% improvement in fuel economy relative to the base system. The ultra capacitor system is not as efficient as the base system.

The new P710 hybrid transaxle for a mid-size 2.5-liter class vehicle was developed based on the Toyota New Global Architecture (TNGA) design philosophy to achieve a range of desired performance objects. A smaller and lighter transaxle with low mechanical loss was realized by incorporating a new gear train structure and a downsized motor. The noise of the P710 transaxle was also reduced by adopting a new damper structure.