Studies of Valve Lifer for Automotive Heavy Duty Diesel Engine by Ceramic Materials II. Development of SiC Valve Lifter by Injection Molding Method

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J. Korean Ceram. Soc. > Volume 35(2); 1998 > Article

Journal of the Korean Ceramic Society 1998;35(2): 172.

Ceramic 재질을 이용한 자동차용 대형 디젤엔진 Valve Lifter 연구 II. 사출성형에 의한 탄화규소질 Valve Lifter 개발

윤호욱, 한인섭¹, 임연수², 정윤중³

KIA-ASIA MOTORS 기술연구소
¹한국에너지 기술연구소
²명지대학교 공과대학 무기재료공학과
³명지대학교공과대학 무기재료공학과

Studies of Valve Lifer for Automotive Heavy Duty Diesel Engine by Ceramic Materials II. Development of SiC Valve Lifter by Injection Molding Method

ABSTRACT

Valve lifter namely tappet is supported by lifter hole which is located upper side of camshaft in cylinder block transforms rotatic mvement of camshaft into linear movement and helps to open and shut the en-gine valve as an engine parts. The face of valve lifter which is continuously contacting with camshaft brings about abnormal wears such as unfair wear and early wear because it is severely loaded in the valve train system. These wears act as a defect like over-clearance and cause imperfect combustion of fuel during the valve lifting in the combustion chamber. Consequently this imperfect combustion makes the engine out-put decrease and has cause on air pollution. To prevent these wears therefore The valve lifter cast in me-tal developed into SiC ceramics valve lifter which has an excellence in wear and impact resistance As a results the optimum process conditions like injection condition mixture ratio and debonding process could be established. After sintering fine-sinered dual microstructure in which prior ${alpha}$-SiC matches well with new SiC(${beta}$-SiC) produced by reaction among the ${alpha}$-SiC carbon and silicon was obtained. Based on the study it is verified that mechanical properties of SiC valve lifter are excellent in Vickers hardness 1100-1200 bending strength (300-350 Pa) fracture toughness(1.5-1.7 Mpa$.$m1/2) Through engine dynamo test-ing SiC valve lifter and metal valve lifter are examined and compared into abnormal phenomena such as early fracture unfair and early wear. It is hoped that this research will serve as an important springboard for the future study of heavy duty diesel engine parts developed by ceramics which has a good wear resis-tance relaibility and lightability.

Key words: Valve train system, Ceramic valve lifter, SiC valve lifter, Injection molding valve lifter