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The wear mechanisms of the methanol engine were studied using dynamometer tests. Formic acid from methanol combustion mixes with the lubricant oil and attacks the metal surfaces. The iso tacho prorissis method was successfully applied to analyze the formic acid content of the used oil. A large amount of condensed water is also formed by methanol combustion and accelerates the wear. Wear can be effectively reduced by shortening lubricant oil change intervals, by using a special oil and by durable surface treatment of engine parts.

Diamond-like carbon (DLC) coating has excellent properties like high hardness and low friction. So it has attracted considerable attention in recent years as a low-friction coating material. However, some DLC coatings display increased wear in oil containing Mo-DTC (Molybdenum-dithiocarbamates). Wear analyses of sliding surface after block-on-ring tests were conducted suggest that the decomposition product from Mo-DTC, MoO3, reacts with active sites in the DLC to promote the wear of DLC.

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.

In order to develop the valve rocker arm material for the new type engine, we investigated various materials whose chemical compositions were selected using 30% chromium cast iron, which had shown good results in screening evaluation tests, as the basis. High chromium cast irons are well known for their abrasive wear resistance, but it has been very difficult to apply them for use as rocker arm material because their machinability is very poor, and because it is difficult for them to have a regular microstructure. In this paper, both the manufacturing method for the rocker arm which decreases the disadvantages that high chromium cast iron have and the rocker arm material best suited for this method are described.

Toyota has developed a new system, which uses integrated control of powertrain by PowerTrain Management (PTM), in order to improve driving comfort and reliability. This system is currently in use on Lexus's new LS460. This system is composed of 4 parts: a generation part, a mediating part, a modification part and a distribution part. In each part, processes are based on drive power and torque. In the generation part, requests from a programmed model driver, Driving Support Computer and Vehicle Dynamics Integrated Management (VDIM) are generated and expressed by drive power. In the mediating part, most suitable vehicle drive power was selected among the requests. In the modification part, the selected request is modified using a programmed powertrain model, which considers internal combustion engine condition and powertrain response and transmission's tolerance. In the distribution part, optimized engine torque and gear ratio are processed.

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.

The torque converter clutch slip control system adopted in the Toyota A541E automatic transaxle engages the torque converter clutch by applying a steady slip speed to prevent the torque fluctuation of the engine to be transmitted to the drivetrain while enhancing the transmission efficiency of the torque converter. The feedback controller of the slip speed adopts the H∞ (H-Infinity) control theory which offers a high level of robust stability, and is the first of its kind in a mass produced component. As a result, a highly accurate and reliable system has been realized, contributing to large-scale fuel economy.

The automobile industry currently faces many challenges which may greatly impact on its foundry operations. One of these challenges, consumers'' demand for greater fuel efficiency, can be met by reducing the weight of castings used in automobiles, and minimizing engineering tolerances. In answer to this particular demand, engine foundries have begun to either produce cylinder blocks or other castings with aluminum rather than cast iron. However, if a reduction in weight (thin wall and near-net shaping) can be realized with cast iron, there would be numerous merits from the perspective of cost and compactness and there would be much more flexibility in automotive parts design.

This paper describes the application of a life prediction method for stainless steel exhaust manifolds. Examination of the exhaust manifold cracks indicated that many of the failures could be attributed to out-of-phase thermal fatigue due to compressive strains that occur at high temperatures. Therefore, the plastic strain range was used as the crack initiation criteria. In addition, the comparison of the calculated thermal fatigue stress-strain hysteresis to the experimental hysteresis made it clear that it was essential to use the stress-strain data that was obtained through tensile and compression testing by keeping the test specimens at the maximum temperature of the thermal fatigue test mode. A finite element crack prediction method was developed using the aforementioned material data and good results were obtained.

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.

This paper describes the preliminary development of an on-board integration network for vehicle dynamics. The underlying philosophy is explained and the basic requirements are set forth. A design conforming to these requirements is presented and the experiments conducted to optimise the physical layer are described. An original token passing protocol is proposed for the access method and evaluated in comparison with the contention method by means of a specially devised simulation system.

The combustion chamber deposit (CCD) forming tendency of gasoline components and detergents were investigated with laboratory tests ad engine dynamometer tests. In the dynamometer tests, the driving conditions under which fuels and detergents influence CCD formation were specified, and the effects of different gasoline components and detergent blends on CCD formation were examined. In the laboratory tests, the CCD forming process was investigated thoroughly [10]. The CCD forming tendency of aromatic compounds in gasoline were dependent not only on physical properties such as molecular weight, but also chemical structure (number or position of the alkyl substituents of aromatic molecules). As for oxygenates, engine dynamometer tests with MTBE blended gasoline yielded less CCD than the test without MTBE. The CCD forming tendency of detergents correlated with the thermal decompositon tendency of the detergent package and the concentration of the main agents.

For a vehicle fatigue and strength testing system, two methods are usually used to accurately simulate the road-load on the test bench: one is the “separation of road-load into multi-axial loads” method and the other is the “compensation with frequency response function” method. These methods have remarkably improved the abnormality detection capability and accuracy of bench testing. For power steering or other units, however, the road-load points drift while the vehicle is driven. Further more, the road-load is applied in a complex manner to the vehicle. These factors make it difficult to separate the road-load into multi-axial loads and to provide stable measurement of the frequency response function. Thus, further progress of these methods has been delayed. The objective of this study was to make the bench testing of power steering units possible.

The change of the fuel flow rate in an injector with mileage accumulation causes poor drivability and exhaust emission deterioration in Otto-type methanol fueled vehicles with a multi-point fuel injection system. This is one of the serious problems which needs to be solved for the practical use of methanol fueled vehicles. The investigation results reveal that the wear of contact surfaces between a valve needle and a valve body increases the resistance force for valve needle movement and causes the change of dynamic fuel flow rate in the injector. The effects of several countermeasures to solve this problem are evaluated.

Recently, the California Air Resources Board (CARB) has proposed a new set of evaporative emissions and “Useful Life” standards, called LEVII EVAP regulations, which are more stringent than those of the enhanced EVAP emissions regulations. If the new regulations are enforced, it will become increasingly important for the carbon canister to reduce Diurnal Breathing Loss (DBL) and to prevent deterioration of the canister. Therefore, careful studies have been made on the techniques to meet these regulations by clarifying the working capacity deterioration mechanism and the phenomenon of DBL in a carbon canister. It has been found that the deterioration of working capacity would occur if high boiling hydrocarbons, which are difficult to purge, fill up the micropores of the activated carbon, and Useful Life could be estimated more accurately according to the saturated adsorption mass of the activated carbon and the canister purge volume.

One-box type vehicles are especially liable to a loss of stability when entering a region of cross-wind. The reasons for this instability were investigated using scale models and by means of a mathematical simulation. Results indicated that yawing moment attains a peak at a precise position of the vehicle relative to the cross-wind. Visualization of the air flow and measurement of the pressure distributions established the cause of the phenomenon. Furthermore a study was conducted into the effects of body shape on stability and the efficacy of various modifications was assessed.

This paper describes application of sintered silicon nitride to the swirl lower-chamber in order to improve performance of turbocharged diesel engines. Various stress analyses by finite element method and stress measurements have been applied to determine the design specifications for the component, which compromise brittleness of ceramic materials. Material development was conducted to evaluate strength, fracture toughness, and thermal properties for the sintered bodies. Ceramic injection molding has been employed to fabricate components with large quantities in the present work. Quality assurance for the components can be made by reliability evaluation methods as well as non-destructive and stress loading inspections. It is found that the engine performance with ceramic component has been increased in the power out put of 9PS as compared to that of conventional engines.

Ongoing research on active stabilizers involves not only control of the roll angle of the vehicle based on steering input but also improving ride comfort by reducing roll vibration caused by the antiphase road surface input. In that context, roll skyhook control, which applies skyhook theory to provide feedback on the vehicle roll and drive the actuators, has already been presented. Although vibration in all frequency bands can be reduced if there is no control delay, time lags or phase delays in control elements such as the communication, computation, low-pass filter, or actuators can amplify vibration. Consequently, a sufficient effect of controlling cannot be obtained. This paper will address wheelbase filtering, which produces a frequency that minimizes roll oscillation, and is used to suppress the influence of the undesirable vibration.