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A helical port with a swirl control valve (SCV) has been developed to satisfy two inconsistent requirements of achieving sufficient swirl generation to improve the combustion and still maintaining high volumetric efficiency. Their effects on combustion were confirmed in a single cylinder engine using high speed flame photography and cylinder pressure diagram analysis which has demonstrated faster combustion. As a result of a hot wire anemometer study, the differences in gas motion were clarified between two helical ports, one with and one without a SCV. A more active movement of the center of swirl was measured in the case of helical port with SCV which suggests the generation of higher turbulence in the cylinder.

Toyota succeeded in the fall of 1984 in manufacturing a complex engine and transmission control system using a newly developed single-chip microcomputer. This microcomputer, equipped with an 8K-byte ROM ( Read Only Memory) and a 256-byte RAM ( Random Access Memory), a powerful real time processing function, and a high-speed optimum instruction set, is better suited for automobiles. Application of the latest CMOS technology has enabled lower power consumption and improved noise immunity. The new system, which includes a new function; the electronic spark advance with knock control in addition to the conventional sophisticated system, has greatly improved the performance and driveability of vehicles.

The lean combustion system, developed for fuel economy inprovement, uses a Lean Mixture Sensor for the feedback control of air-fuel ratio in the lean mixture range. The Lean Mixture Sensor, comprises a zirconia solid electrolyte cell which has an electrochemical pumping action and a ceramic coating layer as a diffusion layer; the measurable range is from the stoichiometric to 25 of air-fuel ratio.

Since the first robot: was introduced into our factory in 1971, about 1250 playback robots have been operated. But processes in which these robots were installed were limited to particular ones such as spot welding, are welding and painting. In many other processes robots have not been installed. Investing the reasons there is a main factor as follows, As to the application of robot, it is hard to evade the diversity of robot type because robots must be different from each other, if the most suitable robots are chosen in setting space, operating area, load capacity, speed and accurary against applied process and work pieces. If standard robots in the market are fitted to various conditions of processes or work pieces, the types of robots increase and many problems are produced on operation and maintenance.

Periodic regeneration of the diesel particulate trap is essential to maintain the collection efficiency and exhaust gas hack pressure at acceptable levels. The objectives of this study are to describe the phenomenology of ceramic foam filter regeneration process and to present its mathematical model. Further simulation study is carried out to estimate the effects of various factors including fuel additive on the ignition and the filter bed temperature and to investigate conditions of excessive temperature which could result in filter destruction. The model is based on the assumption that the regeneration process is composed of two steps. The first step is the additional heat supply from the external energy source, and the second step is the spontaneous combustion propagation. The results from the analytical model agreed very well with the experimental results.

In comparison with conventional hot forging process, powder forging process has much advantage such as good dimensional accuracy, minimum scattering of weight, etc. In spite of much advantage, the powder forged parts have not been mass-produced except for relatively simple shape parts because of technical and economic problems such as low productivity. Solving these problems, powder forging process was applied to connecting rods which required fatigue strength and minimum scattering of weight, and which were complex in shape. As a result, for the first time in the world, mass-production of powder forged connecting rods was carried out, and its properties are as follows; (1) Sufficient fatigue strength (2) Minimum scattering of weight (3) Good dimensional accuracy

In a two-loudspeaker stereophonic reproduction system of a passenger car, the geometrical configuration of the right and left loudspeakers has the disadvantage of being asymmetrical to the listener. For this system, we have made both theoretical and experimental verifications of the effects of strongly reflected sounds on the sound pressure level difference and phase difference between two ears which determine the location of sound image in a small compartment of a passenger car. On the basis of these verifications, we have developed a new sound localization control system. With this system, acoustical effects such as sound expansion and ambience have been greatly improved in a passenger car. In this system, input signals to the loudspeakers are controlled so that the sound image produced by the loudspeaker nearer to the listeners may acoustically move so as to position itself symmetrically with the other loudspeaker with regard to the listeners.

The use of brakes on public roads depends on traffic conditions and the road itself. In order to research into brake usage on various roads and under various conditions, a micro-computer data logging system was developed. The recorded data were analyzed by a large computer and the severity of brake usages was defined. The relationship between the severity and the brake disc rotor temperature was derived, and used to predict brake pad wear/life. The predicted wear coincided fairly clossly with measured wear.

On diesel vehicles, we frequently experience the phenomenon that low frequency fore and aft vibration of a vehicle, occurs at acceleration, does not decline in amplitude easily and rather increases finally. The phenomenon has recently attracted great concern in driveability problems on diesel vehicles. This phenomenon can not be explained well by the simple torsional vibration model of the powertrain with one node, which has been used so far successfully to analyze low frequency fore and aft vibration of a vehicle. So, we have assumed that the undamped vibration occurs through the interaction of the engine and the powertrain. Taking this interaction into consideration, we have constructed a simulation model, with which the undamped vibration can be simulated accurately. By this simulation model, we have estimated the order of magnitude of the effects of various design parameters affecting the undamped vibration.

Concerning the road load of the vehicle, there are many discussions about how to measure and how to simulate it on the chassis dynamometer. Also many studies have been done in our laboratory to find out the best solution in aspects of logic, instruments, procedure and reliability. Our solution resulted in “Simplified Coastdown Method (SCD)” which is featured by the concept of force-based measurement and setting of chassis dynamometer. This method was proposed to ISO as a candidate for the standard procedure under the support of Society of Automotive Engineers Japan. In this paper, the method is evaluated by comparing with current coastdown method and wheel torque method. From a practical point of view such as easiness of instruments handling, applicability of the facilities, simplicity of installation and procedure, we have come to a conclusion that the SCD method is the most suitable procedure

This paper contains an explanation of a Multiplex Wiring System with Optical Data-Link for cars, which has been installed in the Toyota “Century” since 1982. In this system, a total of 64 signals related to door wiring are transmitted in a multiplex fashion, and the number of wires from the front right-hand door to the interior could be reduced from 46 wires, which were used with conventional wiring techniques, to 10 wires including 2 plastic optical fibers. This system also has various control functions which includes a door-lock control function. In order to give high reliability to this system, we have developed a new optical data-link as well as a new custom micro-computer. And in the automobile industry, such a large scale multiplex wiring system having high reliability is very innovative in our opinion and will surely have a large impact in the future.

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 camshaft for an automobile engine is generally made of chilled cast iron. Due to increasing demand for higher performance, lawer maintenance and better fuel economy, it is difficult to make the cast iron camshaft lighter and/or more durable. In order to overcome these problems, development of an integral camshaft comprised of a sintered alloy cam piece for better wear resistance and steel tube for weight saving has been accomplished. In 1981 Toyota Motor Corporation successively started the mass-production of the sintered intergral camshaft for the new 1.8 liter ls engine. The significant advantages are as follows; (1) Weight saving (2) Excellent wear resistance (3) Improvement of lubrication system (4) Saving machining cost

An analysis system for vehicle noise and vibration has been developed. It consists of minicomputer based analog processing system connected with a large main-frame computer. This system features multi-modes for data analysis, fast data processing, data compatibility with conventional analog systems and feasibility. Fast data processing was achieved by newly developed FFT processor and minicomputer software. A new remote control box makes it simple to operate. Data processed by the minicomputer can be transferred to a large mainframe computer for further analysis.

In order to reduce the interior noise of a vehicle with a four-cylinder engine, investigations were made using finite element and vector methods, acoustic intensity testing and holography technique. The investigation resulted in inclination of the engine mounting, design changes to the front suspension member, a shock absorber engine mounting, structural modifications to reduce body panel vibration and a new engine mounting to insulate high frequency engine vibration.