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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.

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.

This paper deals with friction under wet condition in the disk brake system of automobiles. In our previous study, the variation of friction coefficient μ was observed under wet condition. And it was experimentally found that μ becomes high when wear debris contains little moisture. Based on the result, in this paper, we propose a hypothesis that agglomerates composed of the wet wear debris induce the μ variation as the agglomerates are jammed in the gaps between the friction surfaces of a brake pad and a disk rotor. For supporting the hypothesis, firstly, we measure the friction property of the wet wear debris, and confirm that the capillary force under the pendular state is a factor contributing to the μ variation. After that, we simulate the wear debris behavior with or without the capillary force using the particle-based simulation. We prepare the simulation model for the friction surfaces which contribute to the friction force through the wear debris.

A high reliability and low cost temperature sensor for motor vehicle has been developed. The principle of measuring temperature is based on the NTC thermistor. And novel production techniques for sealing and electric connection are presented.

This research proposes an automatic measuring method for the impulse noise of the valve system in engine production line. This research is composed of the following two parts. (1) The most suitable method for indicating the impulse noise of the valve system - the representative characteristic values - is selected from the general measuring methods for impulse noise. As the result, the crest factor in the frequency band above 1kHz became optimal. (2) By detailed sensory characteristic analysis it was found that impulse noise can be heard better with increasing frequency and that there is little influence in the frequency band with the same frequency as the background noise. Thus the crest factor was obtained for each frequency, and the sensory test for the impulse noise of the valve system is deduced by this linear coupling. As the result of multiple reguression analysis, a high accuracy prediction equetion with a multiple correlation coefficient of 0.91 has been obtained.

This paper describes the development of one-piece die cast magnesium steering wheel frame for a steering wheel incorporating an air bag system. The light weight magnesium frame was designed to have proper stiffness, strength and characteristics of energy absorption. Magnesium alloys with various aluminum contents were tested, and AM60B alloy was selected because of its favorable properties of strength and elongation. New manufacturing techniques, for example, a vacuum hot chamber die casting system and a surface defect inspection system were developed in order to produce high quality castings. The characteristics of energy absorption were evaluated in the laboratory and on actual vehicle crash test, and the results were satisfactory. The magnesium steering wheel frame is about 45% (550g) lighter than the steel one. It has been in production in Toyota passenger cars with driver side air bags.

A new type of torque transmit coupling has recently been developed for 4WD cars, that provides a better match to ABS, is of lighter weight, and uses a simpler operating mechanism. This coupling transmits torque with a multi-disc clutch that is engaged by the pressure of high viscosity silicone oil. The rotary blade generates variably the silicone oil pressure, according to both differential speed and direction of rotation between the front and rear wheels. This coupling provides a good match between 4WD performance and four wheel Anti-lock Braking System (ABS) by a modification of the rotary blade shape. No additional devices are needed. This paper describes the characteristics of this coupling and the in-vehicle 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.

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.

This paper describes a new plastic coloring and forming system. The system greatly reduces the time and amount of raw materials necessary for color changes, and eliminates the need for manual cleaning during a color change. This system is well-suited for small-lot production with frequent color changes, as well as for automated production systems. The system is being used by auto parts makers, and is practical in a variety of other fields involved with the coloring and forming of plastics.

The impact of fatty acid methyl ester (FAME) blended diesel fuel on engine/vehicle systems was comprehensively investigated by vehicle, laboratory and engine tests. In this study, 20% FAME blended fuel (B20) was mainly used and soy bean oil methyl ester (SME) was primarily selected as the FAME. Vehicle testing with long-term fuel storage in vehicle fuel tanks was conducted, considering the most severe conditions in market use. Laboratory and engine tests were also conducted to better understand the vehicle test results. In the vehicle test, engine startability, idle roughness and fuel injection control were evaluated using nine vehicles with plastic or metal fuel tanks. All vehicles showed no problems up to 7 months. While five vehicles with plastic fuel tank did not show any problems throughout the test period up to 18 months, four vehicles with metal fuel tanks experienced malfunctions in engine start or fuel injection control following 8, 13, 13 and 18 months respectively.

The hole diameter of injection nozzles in diesel engines has become smaller and the nozzle coking could potentially cause injection characteristics and emissions to deteriorate. In this research, engine tests with zinc-added fuels, deposit analyses, laboratory tests and numerical calculations were carried out to clarify the deposit formation mechanisms. In the initial phase of deposit formation, lower zinc carboxylate formed close to the nozzle hole outlet by reactions between zinc in the fuel and lower carboxylic acid in the combustion gas. In the subsequent growth phase, the main component changed to zinc carbonate close to nozzle hole inlet by reactions with CO₂ in the combustion gas. Metal components and combustion gases are essential elements in the composition of these deposits. One way of removing these deposits is to utilize cavitations inside the nozzle holes.

Oil film thickness is one of the most important issues for optimization of bearing design. A technique has been developed to measure oil film thickness by noting the change in capacitance between the shaft and a thin-film electrode of several micrometers thickness formed on the surface of a bearing. The authors applied this technique to the main journals of an automobile engine and measured the oil film thickness up to maximum speed and full load. The oil film thickness became thinner with increased engine load, and then turned thicker with increased engine speed.

Fuel efficiency improvement measures are focusing on both cold and hot conditions to help reduce CO2 emissions. Recent technological trends for improving fuel economy such as hybrid vehicles (HVs), engine start and stop systems, and variable valve systems feature expanded use of low-temperature engine operation regions. Under cold conditions (oil temperature: approximately 30°C), fuel consumption is roughly 20% greater than under hot conditions (80°C). The main cause of the increased friction under cold conditions is increased oil viscosity. This research used the motoring slipping method to measure the effect of an improved crankshaft bearing, which accounts for a high proportion of friction under cold conditions. First, the effect of clearance was investigated. Although increasing the clearance helped to decrease friction due to the oil wedge effect, greater oil leakage reduced the oil film temperature increase generated by the friction.

Detergent additives in automotive gasoline fuel are mainly designed to reduce deposit formation on intake valves and fuel injectors, but it has been reported that some additives may contribute to CCD formation. Therefore, a standardized bench engine test method for CCDs needs to be developed in response to industry demands. Cooperative research between the Petroleum Association of Japan (PAJ) and the Japan Automobile Manufacturers Association, Inc. (JAMA), has led to the development of a 2.2L Honda engine dynamometer-based CCD test procedure to evaluate CCDs from fuel additives. Ten automobile manufacturers, nine petroleum companies and the Petroleum Energy Center joined the project, which underwent PAJ-JAMA round robin testing. This paper describes the CCD test development activities, which include the selection of an engine and the determination of the optimum test conditions and other test criteria.

A new compact five-speed automatic transmission (A650E) has been developed for front engine rear wheel drive cars. The development of this transmission has been aimed at improving fuel consumption, power performance, engine noise reduction during highway cruising and smooth acceleration by employing a wide range of gearing and close gear ratios. Generally a five-speed automatic transmission is larger than a four-speed, because of additional friction elements and gears. This can result in a change in the floor panel of the car body. However, by removing a one-way clutch for second gear and employing a unique gear-train layout, this transmission has the same circumference and length as the conventional four-speed automatic transmission (A340E)(1).1 In order to reduce first or second gear noise, gear specification and supporting structures of planetary gears have been optimized by FEM analysis.

With the recent improvements in automotive engine performance, the operating conditions for the cylinder head gasket are becoming more critical. Today's cylinder head gasket is required not only to ensure high durability, but also to contribute to improving engine performance. This paper introduces a new metal cylinder head gasket consisting of two beaded plates and a thin sheet in-between. Because of the thin sheet, this gasket has several superior characteristics for open decked aluminum cylinder block engines. Sealability and durability were significantly improved.

A new ABS and Traction control system (TRAC system) has been developed and put into mass production in a new model LEXUS LS400. The TRAC system controls Sub-Throttle Valve and brake hydraulic pressure independently for left and right wheels. To realize the ABS and TRAC system,it is necessary for the Electronic Control Unit (ECU) to process complex algorithm and high speed calculation. The ABS and TRAC ECU for LEXUS LS400 is constructed by 3 TOYOTA custom 8-bit single chip microcomputers. Each CPU performs wheel speed calculation,ABS control and TRAC control,sharing the common data through high speed serial communication. This paper describes the function of each CPU,the method of CPU communication and fail safe function in the ECU.

In order to clarify the diesel fuel spray characteristics inside the cylinder, we developed two novel techniques, which are preparation of same level of temperature and pressure ambient as inside cylinder and quantitative measurement of vapor concentration. The first one utilizes combustion-type constant-volume chamber (inner volume 110cc), which allows 5 MPa and 873K by igniting the pre-mixture (n-pentane and air) with two spark plugs. In the second technique, TMPD vapor concentration is measured by using Laser Induced Exciplex Fluorescence method (LIEF). The concentration is compensated by investigation of the influence of ambient pressure (from 3 to 5 MPa) and temperature (from 550 to 900 K) on TMPD fluorescence intensity. By using two techniques, we investigated the influence of nozzle hole diameter, injection pressure and ambient condition on spray characteristics.

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.