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In order to correspond to the exhaust emissions regulations that become severe every year, more advanced engine control becomes necessary. Engine engineers are concerned about the Hydrocarbons (HCs) that flow through the air-intake ports and that are difficult to precisely control. The main sources of the HCs are, the canister purge, PCV, back-flow gas through the intake valves, and Air / Fuel ratio (A/F) may be aggravated when they flow into the combustion chambers. The influences HCs give on the A/F may also grow even greater, which is due to the increasingly stringent EVAP emission regulations, by more effective ventilation in the crankcase, and also by the growth of the VVT-operated angle and timing, respectively. In order to control the A/F more correctly, it is important to estimate the amount of HCs that are difficult to manage, and seek for suitable controls over fuel injection and so on.

In the field of automotive body electronic control such as control of door locks, power windows, and wipers, there is a growing need of multiplexing communication to reduce the amount of wire harnesses. To meet this need, we developed a multiplexing communication protocol particularly suited to the body electronic control. Based on the developed protocol, we designed a communication control IC and a simple driver/receiver circuit with a few discrete components. The bus access method of the communication is the CSMA/CD with nondestructive bit arbitration, and its bit rate is 5 kbps. Its transmission media is a single wire. The communication IC has a multiplexing control block and a serial I/O block for an interface with a host CPU. It was fabricated using CMOS technology and has a chip of 2.6mm x 3.0mm in size that contains about 5,000 transistors. The driver/receiver circuit consists of one transistor, one capacitor and several resistors.

Development of a new battery system for Toyota Estima Hybrid, the world's first minivan hybrid vehicle, has been completed. The battery pack that consists of 30 nickel metal hydride battery modules is compactly arranged under the 3rd seat in the cabin along with components such as the battery cooling blower and the ducts. This arrangement was designed in consideration of user's vehicle use, passengers' comfort and efficient battery-cooling performance.

The particle number (PN) emission regulation has been implemented since 2011 in Europe. PN measurement procedure defined in ECE regulation No. 83 requires detecting only solid particles by eliminating volatile particles, the concentrations of which are highly influenced by dilution conditions, using a volatile particle remover (VPR). To measure PN concentration after the VPR, a particle number counter (PNC) which has detection threshold at a particle size of 23 nm is used, because most solid particles generated by automotive engines are considered to be larger than 23 nm. On the other hand, several studies have reported the existence of solid and volatile particles smaller than 23 nm in engine exhaust. This paper describes investigation into a measurement method for ultrafine PNCs with thresholds of below 23 nm and evaluation of the VPR performance for the particles in this size range. The detection efficiency of an ultrafine PNC was verified by following the ECE regulation procedure.

Hybrid vehicles (HVs) are becoming more widely used. Since HVs supplement engine drive with motor power, the lubricant oil temperature remains at a lower level than in a conventional gasoline vehicle. This study analyzed the effect of cylinder bore temperature and lubricant oil temperature on engine friction. The results showed that, although the lubricant oil temperature was not relevant, the bore temperature had significant effect on piston friction. It was found that raising the temperature of the middle section of the cylinder bore was the most effective way of reducing piston friction.

Environmental improvement is moving forward, due in part to the reduction of fuel consumption of automatic transmission(AT) vehicles as a result of social requirements in recent years and many measures have been implemented. Adoption of idling stop is a typical example introduced to reduce energy consumption while the vehicle is stopped to improve the urban environment. However, there are problems such as responsiveness and smoothness for an AT vehicle when the engine is stopped with the shift selector in “D” range. To overcome these problems, a new start clutch control system has been developed using an electric oil pump installed in a simple hybrid vehicle called a mild hybrid. As a result, a smooth feeling starting performance is achieved by operating the system in combination with the engine and other systems.

In the twenty-first century, the development of vehicles has been proceeding towards electronics, electric propulsion and system integration in 5 big trends. Environment, Safety, Market Change, Energy Security and Natural Resources. Especially, “Electric Propulsion of Vehicles” is rapidly accelerated for countermeasure of global warming. In this paper, we will propose the current status analysis for automotive high power supply voltage and classification for future view of HEV(Hybird Electric Vehicle). PHEV(Plug-in Hybrid Electric Vehicle) and EV(Electric Vehicle).

In recent years, enhancing engine thermal efficiency is strongly required. Since the maximum engine thermal efficiency is especially important for HVs, the technologies for improving engine thermal efficiency have been developed. The current gasoline engines for hybrid vehicles have Atkinson cycle with high expansion ratio and cooled exhaust gas recirculation (EGR) system. These technologies contribute to raise the brake engine thermal efficiency to more than 38%.In the near future the consumers demand will push the limit to 40% thermal efficiency. To enhance engine thermal efficiency, it is essential to improve the engine anti-knock quality and to decrease the engine cooling heat loss. To comply with improving the anti-knock quality and decreasing the cooling heat loss, it is known that the cooled EGR is an effective way.

Vehicles equipped with in-wheel motors are being studied and developed as a type of electric vehicle. Since these motors are attached to the suspension, a large vertical suspension reaction force is generated during driving. Based on this mechanism, this paper describes the development of a method for independently controlling roll and pitch as well as yaw using driving force distribution control at each wheel. It also details the theoretical calculation of a method for decoupling the dynamic motions. Finally, it describes the application of these 3D dynamic motion control methods to a test vehicle and the confirmation of the performance improvement.

The authors, et al. have succeeded in the practical application of the abradable flame spray coating, used in aircraft engines for the prevention of air leakage and the improvement of efficiency, to automobile turbochargers for the first time in the world. Two layers consisting of a bond coated layer and an abradable layer used to be coated by separate spray nozzles under the conventional technique. In this paper, equations of relations between various flame spray coating conditions and the quality of coated film, which were derived from measured results, will be described. Flame spray coating conditions, that allow the double layer coating by the same spray nozzle, have been determined for each layer. Temperatures and speeds of the flame were measured by means of two-color type high-speed cameras, and equations of their relations with the flame spray coating conditions are derived from the measured result.

Countries and regions around the world are tightening emissions regulations in reaction to the increasing awareness of environmental conservation. At the same time, growing concerns about the depletion of raw materials as vehicle ownership continues to increase is prompting automakers to look for ways of decreasing the use of platinum-group metals (PGMs) in the exhaust systems. This research has developed a new catalyst with strong robustness against fluctuations in the exhaust gas and excellent nitrogen oxide (NOx) conversion performance. This catalyst incorporates rhodium (Rh) clusters with a particle size of several nanometers, and stabilized CeO2-ZrO2 solid-solution (CZ) with a pyrochlore crystal structure as a high-volume oxygen storage capacity (OSC) material with a slow O2 storage rate.

Exhaust and evaporative emissions systems have been developed to match the characteristics and usage of the Toyota THS II plug-in hybrid electric vehicle (PHEV). Based on the commercially available Prius, the Toyota PHEV features an additional external charging function, which allows it to be driven as an electric vehicle (EV) in urban areas, and as an hybrid electric vehicle (HEV) in high-speed/high-load and long-distance driving situations. To reduce exhaust emissions, the conventional catalyst warm up control has been enhanced to achieve emissions performance that satisfies California's Super Ultra Low Emissions Vehicle (SULEV) standards in every state of battery charge. In addition, a heat insulating fuel vapor containment system (FVS) has been developed using a plastic fuel tank based on the assumption that such a system can reduce the diffusion of vapor inside the fuel tank and the release of fuel vapor in to the atmosphere to the maximum possible extent.

Toyota Motor Corporation has been actively pursuing the development of fuel cell vehicles (FCVs) to respond to global environmental concerns and demands for clean energy. Toyota developed the first fuel cell (FC) bus to receive vehicle type certification in Japan. Subsequently, a new FC bus has been developed, which adopts two FC systems and four high-voltage batteries to achieve the required high power performance and durability. For enhanced durability, the FC system is controlled to maximize usage of the high-voltage batteries and to reduce the number of electric potential changes of the fuel cell. To accomplish this, the voltage of the FC stack must be kept high and FC power must be kept low. The high-voltage batteries were used to actively minimize FC power during acceleration.

Toyota Motor Corporation developed the Fuel Cell Hybrid Vehicle (FCHV). The FCHV-4 is an evolution of the conventional fuel cell vehicle that has made immense improvements in efficiency. Both a fuel cell and a secondary battery are used as sources of energy for the hybrid system. By using these energy sources proportionally, the system can be kept at or near its optimum state. The FCHV-4's system is designed to improve the efficiency and aims for high responsiveness when the vehicle is in a transitional state. In the same way as most electric vehicles, and as in the gasoline powered hybrid “Prius”, the energy the traction motor creates during breaking can be used to regenerate the secondary. The fuel cell and traction motor inverter are connected directly, with the secondary battery connected through the DC/DC converter to the fuel cell in parallel.

Previous reports have already described the details of engine start-shock and the mechanism of vibration mechanism in a stationary vehicle. This vibration can be reduced by optimized engine and motor generator vibration-reduction controls. A prediction method using a full-vehicle MBD model has also been developed and applied in actual vehicle development. This paper describes the outline of a new method for the hybrid system of mechanical power split device with two motors that predicts engine start-shock when the vehicle is accelerating while the engine is stopped. It also describes the results of mechanism analysis and component contribution analysis. This method targets engine start-shock caused by driving torque demand during acceleration after vehicle take-off. The hybrid control system is modeled by MATLAB/Simulink. A power management and motor generator control program used in actual vehicles is installed into the main part of the control system model.

The new Toyota FCV “Mirai” has reduced the weight, size, and cost of the high-pressure hydrogen storage system while improving fueling performance. The four 70 MPa tanks used on the 2008 Toyota FCHV-adv were reduced to two new larger diameter tanks. The laminated structure of the tanks was optimized to reduce weight, and a high-strength low-cost carbon fiber material was newly developed and adopted. The size of the high-pressure valve was reduced by improving its structure and a high-pressure sensor from a conventional vehicle was modified for use in a high-pressure hydrogen atmosphere. These innovations helped to improve the weight of the whole storage system by approximately 15% in comparison with Toyota FCHV-adv, while reducing the number of component parts by half and substantially reducing cost. The time required to fuel the FCV was greatly reduced by chilling the filling gas temperature at the hydrogen filling station to −40°C (as per SAE J2601).

Toyota Hybrid System (THS), that combines a gasoline engine and an electric motor was installed in the Prius, which was introduced in 1997 as the world's first mass-produced hybrid passenger car, and was vastly improved in 2003. The new Prius gained a status of highly innovative and practical vehicle. In 2005, combined with a V6 engine, THS had a further evolution as a Hybrid System for SUV, which was installed in the RX400h and Highlander Hybrid to be introduced into the world. This report will explain “new THS” which achieved both V8 engine power performance and compact class fuel economy, while securing the most stringent emission standard, SULEV.

A methanol fueled, lean burn system has been developed to improve both specific fuel consumption and NOx emissions. A 1.6L four-cylinder engine with increased compression ratio has been used to develop this system. Three major components of the Toyota Lean Combustion System (T-LCS) have been applied: (1) A helical port with a swirl control valve (2) A lean mixture sensor (3) Timed, multi-point fuel injection. A 2250 lb. Inertia Weight test vehicle has been fitted with this engine, and fuel system materials have been modified. This methanol, lean burn system has improved the fuel economy by about 12% still satisfying the 1986 emission standards of the U.S.A. and Japan. Aldehyde emissions have also been evaluated.

With an ever growing demand for the enhanced control of a vehicle and for the reduction of power and signal distributing wires in a vehicle, there is a pressing need for the development of Local Area Network (LAN) in a vehicle. LAN enables the exchange of various data among several electronic control units (ECUs), and results in the higher controlled performances of a vehicle and the reduction of the wires. In response to this need, two integrated circuits for vehicle multiplexing communication are developed. One is a communication control IC and the other is a bus driver/receiver IC, both based upon the standard of a PWM type of the J1850 for a communication protocol. The communication control IC is designed to have distinctive features such as a highly fail-safe operation and the reduction of the overhead for communication imposed on a central processing unit (CPU) of the ECU.

Toyota has been evolving a hybrid system since introducing the first mass-production hybrid vehicle in 1997 in response to the increasing automotive-related issues of CO2 emissions, energy security, and urban air pollution. This paper describes a newly developed hybrid system design and its performance. This system was developed with the main purpose to improve fuel consumption, especially for better real world fuel consumption; and to enhance its compatibility with multiple vehicle adoption by downsizing and reducing the weight of its components. At the same time, the hybrid system achieved improved power performance while satisfying stringent emission regulations in the world.