Search Results

An Advanced driving simulator has been developed at Mazda Yokohama Research Center. The primary use of this simulator is to research future driver-vehicle systems. In an emergency situation, a driver must respond rapidly to perceived motion and visual stimulus to avoid an accident. In such cases, because the time delay associated with the perception of motion cues is shorter than visual and auditory cues, the driver will strongly rely upon perceived motion to control the vehicle. Hence, a driving simulator to be used in the research of driver-vehicle interactions in emergency driving must include a high performance motion system capable of large amplitude lateral motion. The Mazda simulator produces motion cues in four degrees of freedom, provides visual and auditory cues, and generates control feel on the steering wheel. This paper describes the merit of the large amplitude motion system and the features of this newly developed driving simulator.

While basic automobile performance is improving along with the growth of higher value-added features, rapidly increasing use of electrical and electronics systems with complex wire harnesses is becoming a problem. This is bringing the automotive distributed control multiplex system to commercial reality. At present, standardization of protocols is under deliberation by SAE and ISO, and several protocols are being considered as candidates. To select a multiplex LSI having an optional protocol, we have established a method to evaluate automotive distributed control multiplex system from the standpoint of users. The method will permit comparison of various multiplex LSIs including physical layers and their protocols' performance/reliability, while helping clarify their features and areas of applications. It is our hope that through this activity of ours, we will be able to make some contribution to global standardization in the field.

Lean-burn technology is now being reviewed again in view of demands for higher efficiency and cleanness in internal combustion engines. The improvement of combustion using in-cylinder gas flow control is the fundamental technology for establishing lean-burn technology, but the great increase in main combustion velocity due to intensifying of turbulence causes a deterioration in performance such as increase in heat loss and N0x. Thus, it is desirable to improve combustion stability while suppressing the increase in main burn velocity as much as possible (1). It is expected that the fluid characteristics of the in-cylinder tumbling motion that the generated vortices during intake stroke breake down in end-half of compression stroke will satisfy the above requisition. This study is concerned with the effects of enhancing of tumble intensity on combustion in 4-valve S. I. engines.

The “R26B” 4-rotor rotary engine is a powerplant that brought a Mazda racing car to victory in the 1991 Le Mans 24-hour endurance race. This engine was developed to achieve high levels of power output, fuel efficiency, and reliability, as required of endurance racing engines. This paper describes the basic structure of the engine, including a 3-piece eccentric shaft that represents a major technological achievement incorporated in the engine, as well as other technological innovations employed for the enhancement of the engine's power output and reliability, and for reducing its fuel consumption. These innovations include a telescopic intake manifold system, peripheral port injection, 3-plug ignition system, 2-piece ceramic apex seal, and a cermet coating on the rubbed surfaces of the housings.

Magnesium has the lowest specific gravity of all metals used for structural members. The application of magnesium for a road wheel leads to improved vehicle handling and drivability because of the reduction of an unsprung weight. The authors have developed new magnesium alloy which shows excellent mechanical properties and attained a magnesium forged road wheel that is 30% lighter than aluminum wheels.

Disk brake rotors require reduced unsprung weight and improved cooling ability for improved fade performance. Automotive brake rotors made from aluminum metal matrix composites (MMC) were evaluated by dynamometer and vehicle tests for the required improvement. The friction and wear performance and the thermal response during fade stops were compared with those of commercially produced gray cast iron (GCI) rotors. It was proved that MMC is a very effective material to replace GCI for brake rotor application, as it reduces unsprung weight and decreases maximum operation temperature of the brake system.

The U.S. Federal Emission Standards ruled that particulate emissions from '87 models should be no more than 0.20 g/mile for passenger cars and 0.26 g/mile for light-duty trucks. A complete ceramic swirl chamber with a heat insulating air gap has been developed to meet the above standards without sacrificing fuel economy or power output. The whole process by which the ceramic swirl chamber was developed will be described: optimization of materials, design, manufacturing, and the method and system of quality control. The results of long term durability tests will be described, which demonstrate the chamber's excellent reliability.

New material and processing technologies were developed for main components of the rotary engine to establish its reliability and durability. The components discussed in this paper are the rotor housing, side housing, and sealing elements. Also described are the material and processing technologies which resolved problems about their strength, rigidity, wear, etc.

At present, various communication protocols for an automotive distributed control multiplex system that aims at solving wire complexity and meeting the requirements of high reliability and open system flexibility have been proposed and installed in production cars. The requirements for an automotive distributed multiplex system, especially reliability, flexibility, and economy have been analyzed in detail, and as a result a new communication protocol based on SAE J-1850 has been developed. This paper describes the design philosophy and technical features of the protocol, named PALNET (Protocol for Automotive Local area Network) and the result of evaluation with the experimental system. PALNET covers moderate speed signals in vehicle electrical and electronic system. Main technical features of PALNET are as follows. Introduction of a new acknowledgement method named ANC (Acknowledgement for Network Control) secures high reliability of data communication.

Today, most widely used synchronizer rings (SNRs) are made of brass (brass SNR). The development of superior SNR to brass SNR has been required for both shift feeling and durability, which are two important requirements for SNRs. Carbon-based friction material (carbon material) is selected to develop superior friction material to brass because carbon material is one of the most durable materials for an application of clutch and brake. Carbon material is placed on the friction surface of SNR (carbon SNR). The structure of carbon material, kinds of raw materials and their combination ratio are selected and optimized. The carbon SNR is confirmed to have higher performance than brass SNR for both shift feeling and durability. At present, our carbon SNRs have been introduced into pickup trucks and SUVs in USA.

The Wankel rotary engine is more compact than conventional piston engines, but its oil and fuel consumption must be reduced to satisfy emission standards and customer expectations. A key step toward this goal is to develop a better understanding of the apex seal lubrication to reduce oil injection while reducing friction and maintaining adequate wear. This paper presents an apex seal dynamics model capable of estimating relative wear and predicting friction, by modeling the gas and oil flows at the seal interfaces with the rotor housing and groove flanks. Model predictions show that a thin oil film can reduce wear and friction, but to a limited extent as the apex seal running face profile is sharp due to the engine kinematics.