Refine Your Search

Search Results

Viewing 1 to 6 of 6
Technical Paper

Valve Spring with High Fatigue Resistance for Automotive Engine

Recently, SiCr clean steel wire for springs on automotive engine valves has been developed. This report describes the characteristics of valve springs subjected to a new manufacturing process using SiCr clean steel wire. The process developed by the authors is as follows: First, form a helical spring with SiCr clean steel wire. Next, quench using the distortion preventing technic --Marquenching--. Temper at a temperature lower than the conventional temperature. Shot peen to the surface layer of the spring. And lastly, polish electrolytically to remove micro surface defects formed through shot peening. Using this new manufacturing process, a valve spring with high fatigue resistance can be produced. At the test stress of 588MPa(τm)±490MPa (τa), the number of cycles to fracture was above 100 million, while the number of cycles to fracture was 4 million using the conventional process with the SiCr clean steel which has the best fatigue resistance for commercial use.
Technical Paper

Lubrication Pump Made of Rapidly Solidified Aluminum Alloy for High Performance Engine

An internal gear-type pump has advantages compared with an external involute gear-type pump, for example, higher mechanical or volumetric efficiency, considerable reduction of weight and dimension in the oil-pump system[1]. This paper presents characteristics of the internal gear type rotors with a modified trochoidal profile in the oil-pump system, and new P/M(Powder Metallurgy) aluminum alloys which satisfy required wear properties as the lubrication oil-pump rotors. Also, the advantage of high volumetric efficiency and discharge performance and excellent properties of the oil-pump rotor with a modified trochoid profile were combined with a R/S (Rapidly Solidified) aluminum alloy in the scavenging pump for racing car engine. Good results without wear or damage after an actual race are also reported.
Technical Paper

High Performance P/M Stainless Steel for ABS Sensor Application

ABS sensor rings for automotive use are becoming smaller and thinner because of the demand for low cost and light weight. Such small thin parts are easier to break as they must withstand the same severe conditions as larger heavier parts. Superior elongation properties, after corrosion testing, are necessary for avoiding breakage and to obtain superior corrosion resistance. We have, therefore, developed such high performance P/M stainless steel with superior elongation and corrosion resistance. Conventional stainless steel has uniform pores on its inner surface which makes allows water penetration thus making corrosion worse and decreasing elongation. It is possible to increase corrosion resistance by changing pore structure (e.g. decrease continual pores) through the addition of special alloys that accelerate the sintering process.
Technical Paper

Friction Characteristics Evaluation of Carbon/Carbon Composite Produced by Carbon Powder Sintering Method

We have developed a new Carbon/Carbon composite (C/C) manufacturing process called the “Carbon Powder Sintering Method [1] (C.P.S.M.)”. This study was conducted to evaluate the friction characteristics of C/C manufactured by the C.P.S.M. as compared with C/C manufactured by conventional methods using a dynamometer. In general, C/C shows a high friction coefficient at a high temperature, but shows a low friction coefficient at room temperature. There is a transition temperature point between both friction coefficients. As a result of this study, it was found that the transition temperature of the C.P.S.M. C/C is lower than for any other conventional C/C.
Technical Paper

Development of High Strength Si3N4 Sintered Body for the Valve Systems of Automotive Engines

The high reliability silicon nitride sintered body and the mirror finish grinding machining technique have been developed, which improved fuel efficiency by reducing weight and friction loss of the valve systems. This ceramics, consists of finer grains (mean grain size:1-3μm) has high strength (σ 3b=1600MPa) and high Weibull modulus (m>20). In the case of motoring test by using this ceramics as the cam follower of the valve systems, it has a durability of more than 10,000rpm., which is approx. 30% higher than that of conventional silicone nitride, against the impact load to which the cam followers were subjected at occurrence of valve bouncing.
Technical Paper

Anti-Lock Brake Sensor Rings with Corrosion and Chip Resistance

As the social aaareness of the need for greater automobile safety has risen, autonolive parts manufacturers have focused a lot of new research and development to aulomotive brake systems. Aith the much rapid advances and steady cost reductions in microelectronics technology, highly reliable, electronically controlled lour-thee1 antilock brake systems (ABS) are beginning to gain broad acceptance. Horever, wide acceptance of ABS depends upon the system and having superior performance, and high reliability at an affordable price. The toothed wheels (sensor rings) used for measuring the wheel velocity in the ABS require high precision in the pitch error of the teeth and specific magnetic properties in order to accurately detect wheel velocity, which is the first signal for brake control. Moreover, as these sensor rings are located close to the wheel, they require increased corrosion resistance ability higher than any other automotive parts.