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In this study, it is purpose to make clear the effect of cavitation phenomenon on the spray atomization. In this report, the cavitation phenomenon inside the nozzle hole was visualized and the pressure measurements along the wall of the nozzle hole were carried out by use of 25-times enlarged acrylic nozzle. For the representatives of regular gasoline, single and two-component fuels were used as a test fuel. In addition, various cavitating flow patterns same as experimental conditions were simulated by use of Barotropic model incorporated in commercial code of Star-CD scheme, and compared with experimental results.

Display devices are required to have some fundamental functions which are brightness & gradation, colorfullness, resolution & sharpness, response time, and suitable size of the picture. Since the CRT (Cathode Ray Tube) is superior to the other display devices in these requirements, it can offer much information efficiently and effectively. Their visibility should not be evaluated only on the basis of some standards for office automation systems. From the point of view of human factors, visibility investigations of the CRTs for automobiles are examined. In this paper the relationship between the chromaticity difference and the luminance contrast for drivers to read the picture easily, and the luminance of the background in the CRTs for drivers not to be dazzled in the nighttime driving are clarified.

Finite element aodels have been developed to analyze drive line and suspension vibration. For the analysis of booming noise, we have addressed the optimization of the differential gear carrier mounting system by using a virtual system and realization of it considering many constraints. To reduce the differential whine noise, a simulation method considering the transmitting error of the differential gear was applied. And we have approached for the subtle arrangements of many structural resonances with detail research of the drive line and suspension. For the reduction of road noise, we adopted the approach of shifting the node of the rear suspension member mode.

An active suspension system controls a spring constant and an attenuater in real time using a power supply. Generally, the hydraulic pressures are used for transmitting the power. Therefore, a highly reliable and inexpensive control system has been required for a commercial use. This has been achieved by developing a mechanical fluid servo valve which comprises a simple combination of a solenoid valve and a spool valve. The technical problem of the valve vibrations has been solved through the numerical analyses, the fluid flow visualization tests and the vehicle tests.

Grip feeling is an important facet in vehicle dynamics evaluation from a driver satisfaction and enjoyment standpoint. To improve grip feeling, we analyzed the subjective comments from test driver's about grip feeling and an evaluated human sensitivity to lateral motion. As a result, we found that drivers evaluate transient grip feeling according to the magnitude of lateral jerk. Next, we analyzed what vehicle parameters affect lateral jerk by using theoretical equations. As a result, we found that cornering power is an important parameter, especially the cornering power of rear tires as they can be create larger lateral jerk than can front tires.

Improvement of vehicle dynamics in limit cornering have been studied. Simulations and tests have verified that vehicle stability and course trace performance in limit cornering have been improved by active brake control of each wheel. The controler manages vehicle yaw moment utilizing difference braking force between left and right wheels, and vehicle deceleration utilizing sum of braking forces of all wheels.

In-wheel motors (IWM) will be a key technology that contributes to the popularization of electric vehicles. Combining electric drive with IWM enables both good vehicle dynamics and a roomy interior. In addition, the responsiveness of IWM is also capable of raising dynamic control performance to an even higher level. IWM enable vertical body motion control as well as direct yaw control, electric skid control, and traction control. This means that IWM can replace most control actuators used in a vehicle chassis. The most important technology for IWM is to enable the motor to coexist with the brake and the suspension arms inside the wheel. The IWM drive unit described in this paper can be installed with a front double wishbone suspension, the most difficult configuration.

This paper describes and confirms the effect of low frequency sinusoidal steering torque input on vehicle response and steering behavior using vehicle test, analysis with equations of motion and simulations. The vehicle response by low frequency torque input is quite different to the vehicle response by low frequency steer angle input. Steering system parameters such as moment of inertia, damping, friction and power steering assist torque have an effect on low frequency torque input steering system dynamics. The dynamic response of the vehicle with electric power steering (EPS) system, which has a big moment of inertia with electric motor and friction of the reduction gear, is affected by the steering system dynamic properties. The vehicle response by low frequency torque input test has capability for contribute to vehicle evaluation such as steer feel or maneuverability of handling.

In vehicle control systems such as ABS (anti-lock braking system) or active suspension control, sensors for detecting longitudinal and/or lateral acceleration of vehicles (acceleration of up to ± 9.8 m/s2, with frequency range of DC to 20 Hz) is necessary. The principle of acceleration detection for this sensor is as follows. A permanent magnet levitates steadily in magnetic fluid by the action of the magnetic field generated by the magnet itself. The magnet moves by the application of acceleration on the mass of the magnet. This change of position of the magnet is detected by the Hall element, and thus acceleration is measured as an electrical signal. This sensor consists of only magnetic fluid, a permanent magnet, housing, a pair of Hall elements and an electronic circuit.

Sensors which can detect minimal acceleration such as ± 9.8 m/sec2 in longitudinal and lateral direction of a vehicle, for DC to 20 Hz range, are required to control ABS (anti-lock braking system) or suspension system. To fulfill these requirements, we have developed a one-dimensional acceleration sensor, using magnetic fluid, to control the vehicle. In 1992, we submitted a paper on this sensor at the SAE International Congress and Exposition. Based on this one-dimensional acceleration sensor, we have developed an acceleration sensor which can detect two dimensional acceleration using a single inertia mass. This sensor is compact and can detect minimal acceleration with high accuracy. Spring and damping functions were obtained via the adoption of magnetic fluid, as in the case of the former one-dimensional acceleration sensor. This sensor can sustain mechanical shocks.

A phosphor thermometry, for measurements of two-dimensional gas-phase temperature was examined in turbulent combustion in an engine. The reasonable temperature deviation and the agreement with calculated data within 5% precision were achieved by single-shot images in the ignition process of compression ignition engine. Focusing on the local flame kernel, the flame structure could be quantitatively given by the temperature. It became evident that the HCCI flame kernels had 1-3 mm diameter and the isolated island structures. Subsequently, the HTR zone consisted of the combined flame kernels near TDC.

Excessive throttle pedal operation while driving on slippery roads causes the wheels to spin, consequently reducing vehicle stability and traction. Driving a vehicle under these conditions imposes additional and unneccessary burdens on the driver. To solve the problem, a traction control (TRC) system controlling engine torque and brake force has been developed to prevent the driven wheels from excessive spinning. The TRC system consists of some additional components to the Antilock Brake System (ABS), a system which had previously been developed to prevent wheels from locking up during hard braking. The combination of the ABS and the TRC system will now be effective to assist the driver to improve the vehicle driving performance on slippery road surfaces.

TOYOTA MOTOR CORPORATION had developed the world's first microprocessor controlled suspension system, Toyota Electronic Modulated Suspension (TEMS), which is now being offered on the Toyota Soarer from Feb. '83. This system consists of sensors, switches, electronic control unit (ECU), actuators and shock absorbers. TEMS uses a microprocessor to adjust the damping forces of the front and rear shock absorbers. As a result, suspension can be tuned in two stages (hard and soft cushioning) and driver can choose three control modes (AUTO, SPORT, NORMAL). In AUTO mode, the TEMS system has achieved attitude controls (i.e. squat control, roll control and nosedive control). The TEMS system achieved a 15 - 30% decrease of squat, a 20 - 30% decrease of roll angle, a 10 - 30% decrease of nose-dive and a 30 - 40% decrease of shift-squat.

Advanced electronic control system of suspension and air springs are combined with the double wishbone type suspension. Damping force, spring rate and vehicle height can be automatically con-trolled among three levels in response to the vehicle running conditions.

Toyota has developed a new full time 4WD system, called “EC-HYMATIC” or Electronically Controlled - HYdraulic Multi-plate clutch Active Traction Intelligent Control. This system permits an automatic torque transfer, depending on driving conditions, for front and rear wheels under control of the speed difference between the two. The system developed consists of a center differential, a speed difference control clutch system employing multi-plate clutch, and a gear set for rear axle drive. The speed difference control clutch system is controlled by a unique electro-hydraulic system using a microcomputer. An extensive use of computer simulations and vehicle test and evaluation has successfully developed an appropriate control strategy for the clutch system. The new 4WD system, EC-HYMATIC, considerably improves handling characteristics, traction performance and stability of a 4WD vehicle.

This paper describes a simulation study of the internal fluid flow of a torque converter. The study was conducted by using the steady-interaction technique to connect the boundaries between neighboring elements. This technique averages the flow variables in the circumferential direction on the connecting boundary surfaces. A comparison of computational results with experimental data gives an estimate of the accuracy in predicting torque converter performance with this method.

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.

This paper describes an analysis of the rise in timing belt temperature occuring under high engine speed operation that was made to establish the cause of heat deterioration of the belt materials. Surface temperatures of the belt were accurately measured by correcting thermo-vision detected radiations to eliminate environmental radiation. The temperature profile of a belt cross-section was obtained by a specially developed thermo-couple device. The experimental results indicated that heat generated by the belt contributes significantly to the temperature rise and that the primary cause of the heat generation is bending hysteresis of the belt cords. In addition, a description is made of a method of calculating the rate of heat generation in the belt. In this simulation method, the energy dissipated as heat is calculated from the bending strains and loss moduli of the belt materials. Calculated results were found to agree well with experimental results.

One of the innovations for the Lexus LS400 is the development of a traction control system (TRAC system). The TRAC system suppresses the spinning of the driven wheels, which occurs easily on slippery roads during excessive acceleration, and it improves the acceleration performance and the stability of the car. The TRAC system controls the engine sub-throttle angle and the brake hydraulic pressure for the driven wheels in the same way as the traction control system for the 1987 Toyota Crown. But, acceleration performance and stability of Lexus LS400 is better than Crown as a result of good wheel spinning control by additional improvements of the throttle and brake control methods. Especially as the TRAC system controls the brake hydraulic pressure individually for left and right wheel, the car acceleration performance on split-μ surfaces is improved notably.

In order to reduce CO2, EV and Hybrid Vehicle (HV) are effective. Those type vehicles have different power train from conventional vehicle. Those new power trains drastically improve their efficiency from conventional vehicle with keeping same or superior power performance. On the other hand, those vehicles have the issue for thermal energy shortage during warming up process. The thermal energy is very large. The thermal energy seriously affect on the fuel economy for HV and the mileage for EV. In this paper, the power performance, the fuel economy and the effect of heat energy recovery from the exhaust gas are discussed for HV. For the power performance, the simulated acceleration time of 0-100km/h was 11.8sec and the measured vehicle time was 11.9sec. The error between simulation and actual measurement result was 1.2%. As for the fuel economy, the energy management using exhaust gas heat exchange system improved 10.3% of the fuel consumption during warming up.