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The efficiency of the NOx Storage and Reduction (NSR) catalysts used in the aftertreatment of diesel engine exhaust gases can potentially be increased by using reactive reductants such as CO and H₂ that are formed during in-cylinder combustion. In this study, a multi-dimensional computational fluid dynamics (CFD) code coupled with complex chemical analysis was used to study combustion with various fuel after-injection patterns. The results obtained will be useful in designing fuel injection strategies for the efficient formation of CO.

This paper provides a description of a newly developed dynamometer capable of measuring torque at speeds up to 90,000 rpm. The development which has been made enables the dynamometer to measure output of a small single shaft gas turbine engine without a speed reducing gear box. The unit consists of a high speed generator to absorb the power and a torque measuring device. Since the generator is a key component of this dynamometer, a substantial portion of this paper is devoted to describing the configuration of the generator and the design considerations, as well as its performance. The rotational speed of turbomachines is gradually being increased and will be accelerated further as ceramic materials are introduced. The subjects to be discussed here will, hopefully, be of some use when a torque measuring device for speeds over 100,000 rpm becomes necessary.

A very difficult problem exists regarding windshield shape, and that is to create a balance between aerodynamics and optical distortion. To assist in solving this problem, this study, concerning the characteristics of visual perception for the optical distortion when drivers receive visual information through a windshield, was carried out. In this study, the windshield area was divided into 4 zones from the viewpoints of the level of drivers' fixation frequency and types of objects observed. Distortion was defined as the gap angle ( distortion angle ), which crossed the lines of a grid board with and without a windshield, and distortion angles were measured on a total of 4 windshields. Four drivers indicated areas in each windshield in which they felt the area was distorted. As a result, the thresholds of optical distortion were shown as a function of the horizontal and vertical distortion angles by discriminatory analysis.

The authors developed a low-speed in-vehicle network for the body control system on passenger cars, where the most remarkable effects to reduce the number of wire harnesses could be expected. First, the authors analyzed the body control system to clarify the specifications required to build a low-speed in-vehicle network. Then the authors worked out optimum communication protocol, placing emphasis on cost reduction which is the key to expanding the applications of the low-speed in-vehicle network over wider fields. The low-speed in-vehicle network was evaluated for its performance through simulation and on-vehicle tests, and proved the practical validity of the concept. It was also verified that introducing the low-speed in-vehicle network has a satisfactory effect to reduce the number of wire harnesses.

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.

A new 4.5 liter in-line 6 cylinder engine,1 FZ-FE has been developed for the Toyota Land Cruiser. To obtain high power, fuel efficient engine, we adopted the most advanced Toyota technologies, such as Toyota original 4 Valve DOHC system with scissors gear between camshafts, compact combustion chamber with smooth inlet and outlet system, KCS and so on. The engine produces 212 HP at 4600 rpm and 275 ft-lbs at 3200 rpm. Aluminum cylinder head,short skirt cylinder block stiffened with aluminum oil pan give the engine light weight and make it rigid enough to have low vibration and quietness. And we also designed every engine part appropriately so as to make the engine durable enough in severe operating condition of off-road vehicle.

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.

A new experimental method, that enables to estimate the body and driveline sensitivity to unit transmitting error of a hypoid gear for automotive rear axle gear noise, has been developed. Measurements were made by exciting the tooth of the drive-pinion gear and that of the ring gear separately using the special devices designed with regard to simulation of acceleration and deceleration. The characteristic of this method is to estimate the forces at the contact point of the gears. Estimation of these forces is carried out under the condition that the higher stiffness is provided by the tooth of the drive-pinion gear and that of the ring gear, compared with the stiffness of the driveshafts and that of the propeller shaft etc., and relative angular displacement of the torsional vibration between the teeth of the drive-pinion gear and those of the ring gear is constant.

A laboratory scale simulation test method was developed to evaluate deterioration of radial lip seals of fluoroelastomer (FKM) compounds for engine crankshafts. The investigation of the collected radial lip seals of FKM compounds from the field with service up to 450,000km indicated that the only symptom of deterioration is a decrease of lip interference. This deterioration was not duplicated under conventional test conditions using an oil seal test machine because sludge build up at the seal lip caused oil leakage. However, revised test conditions make it possible to duplicate the deterioration experienced in the field. An immersion test using a radial lip seal assembled with the mating shaft was newly developed. This test method was found to be useful to evaluate deterioration of radial lip seals using FKM compounds. Oil additives affect the deterioration of lip seal materials significantly. Therefore, immersion tests of four different oils were conducted to evaluate this effect.

To meet the requirement for higher performance engine bearings, the microgrooved bearings, that is the plain bearings with shallow circumferential grooves, have been developed. Recently, the performance of microgrooved bearings obtained experimentally have reported1)2). The authors calculated the bearing performance of the microgrooved bearings by elastohydrodynamic lubrication theory. In this paper, the authors described thecalculation method and the performance of the microgrooved bearings obtained theoretically.

A discomforting noise can sometimes be heard in a vehicle passenger compartment during acceleration which can be annoying to passengers. We call this noise a “rumbling noise”. A detailed study of the rumbling noise spectrum has clarified the generating mechanism of the rumbling noise and the relation between the spectral structure and the tone. In order to analyze the rumbling noise, we simulated it with electrically synthesized noise. This method showed that at the times when the noise is heard there are always more than three discrete harmonics which are half an order harmonics of the engine revolution. The sensation of discomfort depends on the phase, frequency and magnitude of each frequency component. To evaluate the noise quantitatively, we also analyzed the shape of the time domain noise envelope. The envelope shape has a good correlation with the feelings of discomfort.

Brake squeal is caused by dynamic instability, which is influenced by its dynamic unstable structure and small disturbance of friction force variation. Recently, FE Analysis of brake squeal is applied for brake design refinements, which is based on dynamic instability theory. As same as the refinement of brake structure is required for brake squeal reduction, the refinement of pad materials is also required for brake effectiveness and brake squeal reduction. It is well known that friction film, which is composed of polymers like phenol formaldehyde resin and so on, influences for friction coefficient. Therefore it is expected that the refinement of polymers in pad materials enable higher brake effectiveness and less brake squeal. In this paper, Molecular Dynamics is applied for the friction force variation of polymers in pad materials. The MD simulation results suggest the reduction method of friction force variation of polymers.

This paper describes an unique concept for the optimum design of tooth modifications of helical gears. The tooth modifications of helical gears will minimize transmission error under various loads with flexible supporting members, i.e. automobile transmissions. The key point of this concept is the amount of tooth modifications on each path of contact moved by misalignment under each respective target torque. Using this concept, it is possible to calculate the optimum 3-dimensional tooth modifications. The tooth modifications under light load will be a small curvature, and a large curvature under high load. Furthermore, through observation we can determine that the tooth surface modifications will have excellent impact on transmission error over a wide torque range. Finally, this method is verified experimentally in various misalignment conditions.

In the field of automobile disk wheels, demands for aluminum wheels have been increasing for the reason of ride comfort and better appearance. And over 90 percent of luxurious passenger cars are equipped with aluminum wheels. This trend is spurred also by the demand for higher fuel efficiency for the cause of environmental protection, which calls for weight reduction of automobiles. This paper reports our research on manufacturing light-weight, high-quality aluminum cast wheels; covering the entire process from basic design to casting, and placing emphasis on the following three points. 1) Determination of optimum wheel configuration through computer simulation 2) Selection of optimum material composition 3) Optimization of the thin plate casting conditions Combination of the above technologies developed for the purpose of weight reduction resulted in the weight reduction of approximately 20% over the conventional aluminum wheels.

It is well known and a common experience among drivers that controllability and stability of a car-trailer combination is affected when an articulated Heavy Goods Vehicle overtakes. In this paper, aerodynamic effects to a car-trailer combination when it is overtaken by an articulated HGV, have been analyzed experimentally using 1/20 scale models in wind tunnel, and a method to suppress this phenomenon has been investigated. The dynamic behaivor of a car-trailer combination is simulated by a simple mathematical model. The result shows that a car-trailer combination can be stable following the addittion of aerodynamic devices to each side of the vehicle. This simulated result is verified by the on-read test.

In recent years, a number of different Blind Spot Monitor (BSM) systems have become more and more popular in North American automotive market. The BSM system advises the driver of vehicles travelling in adjacent lanes when these vehicles are also in the driver's outside rearview mirror blind spots. Similarly, when the vehicle is backing up from a parking spot, cross-traffic vehicles can be in the driver's outside mirror blind spots. In this situation, the Rear Cross Traffic Alert (RCTA) system alerts the driver when the driver shifts the vehicle in the reverse gear and there are approaching cross-traffic vehicles. The benefits of RCTA system was presented by [1]. The RCTA alert studied in this paper is given by playing an audible sound and by flashing the outside mirror indicators. The RCTA and BSM systems share the same vehicle sensors and most of their vehicle components.

The present paper describes an application of non-parametric shape optimization to disc brake squeal phenomena. A main problem is defined as complex eigenvalue problem in which the real part of the complex eigenvalue causing the brake squeal is chosen as an objective cost function. The Fre´chet derivative of the objective cost function with respect to the domain variation, named as the shape derivative of the objective cost function, is evaluated using the solution of the main problem and the adjoint problem. A selection criterion of the adoptive mode number in component mode synthesis (CMS), which is used in the main problem, is presented in order to reduce the computational error in complex eigenvalue pairs. A scheme to solve the shape optimization problem is presented using an iterative algorithm based on the H1 gradient method for reshaping. For an application of the optimization method, a numerical example of a practical disc brake model is presented.

The vehicle requires high brake performance and mass reduction of disc brake for vehicle fuel economy. Then disc brake will be designed by downsizing of disc and high friction coefficient pad materials. It is well known that disc brake squeal is frequently caused by high friction coefficient pad materials. Disc brake squeal is caused by dynamic unstable system under disturbance of friction force variation. Today, disc brake squeal comes to be simulated by FEA, but it is very difficult to put so many dynamic unstable solutions into stable solutions. Therefore it is very important to make it clear the influence of friction force variation. This paper describes the development of experimental set up for disc brake squeal basic research. First, the equation of motion in low-frequency disc brake squeal around 2 kHz is derived.

In emerging markets, Port Fuel Injection (PFI) technology retains a higher market share than Gasoline Direct Injection (GDI) technology. In these markets fuel quality remains a concern even despite an overall improvement in quality. Typical PFI engines are sensitive to fuel quality regardless of brand, engine architecture, or cylinder configuration. One of the well-known impacts of fuel quality on PFI engines is the formation of Intake Valve Deposits (IVD). These deposits steadily accumulate over time and can lead to a deterioration of engine performance. IVD formation mechanisms have been characterized in previous studies. However, no test is available on a state-of-the-art engine to study the impact of fuel components on IVD formation. Therefore, a proprietary engine test was developed to test several chemistries. Sixteen fuel blends were tested. The deposit formation mechanism has been studied and analysed.

Engine control systems were the precursor of scale automotive electronics systems using microcomputers. Toyota Motor Corporation introduced high - level, total control of the power train by applying system integration through introducing a multi - CPU system to the 1988 MY Toyota Camry. Integration in the ECU has been promoted to parallel with system integration. By adopting single - chip microcomputers, monolithic ICs, and hybrid ICs all designed and developed for car electronics, and semiconductor barometric pressure sensors for car electron into ECU's. etc. ever - expandable functions can be provided in a smaller and more lightweight ECU package with higher reliability.