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By developing a mechanical-firing sensor using rotational inertia effect, we have completed miniaturization of the sensor and have developed a new-type mechanical-firing airbag system. This airbag system has been confirmed to have superior occupant protection performance after conducting a variety of vehicle crash tests and sled tests.

Development of a system which utilizes technology for the recognition of a vehicle's surroundings. Research is currently taking place in many countries, the goals of which are to improve a vehicle's safety and convenience by reducing driver strain through the automation of the recognition, judgment, and operation capabilities that are needed when driving an automobile. To recognize the vehicle's surroundings, we have adopted an image sensor system which offers superior three-dimensional recognition capabilities. In this paper, we will introduce a inter vehicle distance control system which controls the vehicle's throttle and braking functions by detecting the position of the driving lane and the distance to the vehicle in front based on the images obtained by a CCD camera.

Sport Utility Vehicles (SUV) and light duty trucks have gained in popularity for the last several years and the demand for more car-like behavior has increased, accordingly. Two areas for potential improvement are vehicle stability and maneuverability while parking. 4WS (4 wheel steering system) is known as an effective solution to stability and low speed maneuverability. In this paper, we identify a new systematic design method of two degree of freedom vehicle state feedback control algorithm that can improve vehicle stability, and show its control effects for a SUV with trailer towing. Low speed maneuvering is improved when the rear tires are steered in negative phase relative to the front tires. However with a large rear steer angle at low speed, the vehicle's rear overhang tracks a wider swing-out path than a 2WS vehicle. For this concern, we propose a new swing-out reduction control algorithm.

We have developed an electric rear-drive unit to enable all-wheel drive (AWD) applications to the compact FF hybrid passenger vehicles. The development is intended to provide a compact and low cost unit with low fuel consumption. The unit newly introduces a two-axis gear train that enables a compact design, an induction motor and an ATF (automatic transmission fluid) stirring resistance restraining structure that contribute to lower fuel consumption. This paper presents the features and performance of the electric rear-drive unit.

Over the past decades, the automotive industry has made significant efforts to improve engine fuel economy by reducing mechanical friction. Reducing friction under cold conditions is becoming more important in hybrid vehicle (HV) and plug-in hybrid vehicle (PHV) systems due to the lower oil temperatures of these systems, which results in higher friction loss. To help resolve this issue, a new internal gear fully variable discharge oil pump (F-VDOP) was developed. This new oil pump can control the oil pressure freely over a temperature range from -10°C to hot conditions. At 20°C, this pump lowers the minimum main gallery pressure to 100 kPa, thereby achieving a friction reduction effect of 1.4 Nm. The developed oil pump achieves a pressure response time constant of 0.17 seconds when changing the oil pressure from 120 kPa to 200 kPa at a temperature of 20°C and an engine speed of 1,600 rpm.

We have developed a Hall effect device based height sensor of a smaller size, and with higher temperature operation durability, as compared to conventional devices. Downsizing of the sensor is realized by decreasing a number of parts, and by employing a short bearing. Improvement in heat resistance is achieved by adopting an IC with sufficient heat resistance and a SmCo magnet with high coercive force. In addition, a sensor of a high degree of accuracy is accomplished by improvements in linearity and robustness of magnetic characteristics. Development of a small, heat-resistant and accurate height sensor will promote the spread of systems using a height sensor, such as a High Intensity Discharge (HID) headlamp.

One of the problems concerning T/M is conventionally how “Improving the input torque as the engine gets higher power” and “Making product lighter in weight and more compact to improve the fuel consumption” can be realized at the same time. To realize these things at the same time, it is needless to say that the gears must be stronger. For the “pitting fatigue strength” which is quoted as a problem lately, the fatigue mechanism has not been clarified, yet. Therefore, it is now a big problem how to achieve high strength. In the meantime, we tried to develop the production engineering for “finer crystal grains” and “fine-dispersion precipitation of carbo-nitrides,” and succeeded in improving “pitting fatigue strength” remarkably. Such results will be reported in the following sections:

Introduction of occupant classification system which has load sensor with a strain gauge built into the seat structure, and identifies occupant's physique by measuring weight on seat, and meets the United States FMVSS requirements (new FMVSS208 Requirement).

We have developed permanent magnet assisted synchronous reluctance motor (SynR motor) using inexpensive permanent magnet (ferrite magnet) for a drive motor of an electric vehicle (EV) or a hybrid electric vehicle (HEV). The objective of this development is to reduce the motor cost by utilizing reluctance torque without using expensive magnet (NdFeB magnet). We confirmed the developed motor is applicable by the test result when the motor performance is adapted to the system specification with high speed. Such motor design and evaluation result will be introduced hereinafter. Further, in this paper, we also introduced the comparison with a switched reluctance motor (SR motor), which we have been developing separately.

We have developed a power sliding door (PSD) system driven by a push-pull cable. The door closure and slide are operated by different actuators to limit the force required for a compact, light-weight drive unit. This paper introduces the concept of the PSD system using a push-pull cable drive. Two new technologies to achieve the PSD system are also described. One is the door position control for increasing the push-pull cable reliability. The other is a compact position sensor to accurately detect the sliding door's position.

Rear steering system can improve vehicle stability using active control of the rear wheel angles. For designing the rear steering system, environmental conditions, performance deterioration due to aging and component variation as a result of manufacturing tolerance under mass production must be taken into consideration. We have applied two-degree-of-freedom (2DOF) feedback control with feedforward control for the motor servo control so that the rear steering actuator can track the target rear steering angle accurately and stably. The control system is designed based upon a nominal mathematical model and its variation range. As a result, the rear steering actuator can be controlled with excellent performance and high reliability. This paper describes the mathematical model construction in the frequency domain and a robust motor servo controller design based on 2DOF feedback control with feedforward control.

Drive train components (transmission, differential gears, etc.) can be made smaller and lighter if the excessive torque exerted on them can be reduced during the quick start of a vehicle. An orifice put in the hydraulic clutch piping path is an effective method. However, increased oil viscosity at low temperatures (0°C or below) makes the “pedal feel” worse. In order to increase the orifice diameter for better “pedal feel”, a shape memory alloy spring, for operation at low temperatures, was developed by adding cobalt to the nickel-titanium alloy. Consequently, a Variable-Orifice valve, using the shape memory alloy spring, is practical.

Switched Reluctance Motor (SRM) mainly has two advantageous characteristics such as no magnet and simple construction. These characteristics contribute lower cost and higher reliability compared with other motor systems such as brushless permanent magnet motors or induction motors. However, acoustic noise and output torque ripple should be improved when the SRM is applied to a traction system for passenger electric vehicle since these characteristics directly affect vehicle quietness and drivability. In this paper, we describe a system configuration of the SRM traction system for passenger electric vehicle. The SRM traction system includes an electric motor, transmission gears and power inverter module. Then, an approach to improve acoustic noise and output torque ripple is introduced. Generation mechanisms of acoustic noise and output torque ripple are analyzed.

There are such outside door handles called smart handles which have a transmitting antenna, a lock/unlock sensor, and a sensor detection circuit, with which operation of door lock is possible just by "touching" the electrostatic-capacitance type sensor of the handles.As the design of the outside handles, body color painting and Cr plating are adopted. However, if plating is applied over the entire surface of a smart handle, electromagnetic waves transmitted from the antenna will be blocked since plating material is electrically conductive. In addition to this, touching a part other than the sensor may change the electrostatic-capacitance of the sensor, which results in unwanted functioning of the lock/unlock sensor. Because of this, only part of the handle, which does not hinder the transmission of electromagnetic waves and does not cause unwanted functioning, is covered by plating, that is called, "Partially plated specifications" (Figure 1).

Switched Reluctance Motor (SRM) mainly has two advantageous characteristics such as no magnet and simple construction. These characteristics contribute lower cost and higher reliability compared with other motor systems such as brushless permanent magnet motors or induction motors. However, SRM has disadvantages that are its torque ripple and acoustic noise in particularly. Moreover, the resonance frequency mode of a motor system is excited by torque ripple, and drive train vibration is caused. These noise and vibration should be suppressed when the SRM is applied to a traction system for passenger electric vehicle since these characteristics affect vehicle quietness and drivability. In this paper, we describe an approach to suppress drive train vibration and acoustic noise.

In this paper, we discuss vehicle directional stability and introduce advanced stability control (ASTC) to stabilize the vehicle during severe cornering. Vehicle behavior in a transient steering condition during severe cornering was analyzed by computer simulation. It was found that applying an external yaw moment makes the vehicle more stable. The effect of controlling the brake force response is also evaluated by simulation to determine the brake actuator response criteria. The actual vehicle test was performed with a pylon slalom using a hydraulic brake actuator. It is verified that the ASTC stabilizes the vehicle for transient steering maneuvers.

Aiming at improved reliability and cost reduction of position sensors for automobiles, we tackled with the challenge of developing long life contact type potentiometer which has a simple construction and cost advantage. We made clear the wear characteristics of the resistor materials and the mechanism how noise occurs, and developed a long life, low noise resistor material, and the double - layer resistor structure which has excellent characteristic in durability. We also clarified the ways of using brushes according to applications through the investigation of the relationship between the contact shape and the amount of wear of the resistor. Based on these investigation, we have developed a highly reliable throttle position sensor and a long life vehicle height sensor.

We have developed Sensor-less Memory Seat system that requires no position sensors such as Hall ICs etc.. It detects the rotation of DC motor by current ripple signals in motor operating current. The developed Sensor-less position control system can attenuate a wide frequency variation of Motor current noise which varies depending on motor condition and convert small current ripples to Pulse signals in proportion to the rotation of DC motor. We realized low cost position control method for use in Memory Seat system.

As automotive electronic systems advance, the wire harness is the mainstream for necessary wiring in resin-made motor-driven actuators with wire connection labor and purchased-parts accounting for the majority of costs. As a means to eliminating the harness, there is a method of forming the conductive material on the inside, but this method leads to cost increases when there is a comparatively large number of wires because the required die insertion time becomes longer and automatic insertion equipment becomes necessary. The following paper reports on an integrated high-speed process that combines stamping and injection molding into a single process.

We developed amorphous alloy thin films having TCR(temperature coefficient of resistivity) less than ±5 ppm/°C for strain gauge applications. Thin film strain gauges are directly formed on metal substrates insulated with SiO2. These gauges have excellent aging stability at high temperature. The resistivity shows a drift in ▵R/R less than ±0.03% at 120°C in 1000 hours. We developed a pressure sensor and an acceleration sensor with high accuracy and reliability, employing these gauges.