Transactions of the Korean Society of Automotive Engineers (한국자동차공학회논문집)

The Korean Society of Automotive Engineers (한국자동차공학회)
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The Effects of Valve Timing Dual Equal Retard/Advance on Performance in an SOHC SI Engine

흡배기 밸브시기 동시 변경이 SOHC SI 엔진성능에 미치는 영향

  • 엄인용 (서울산업대학교 기계공학과) ;
  • 이원근 (현대자동차 파워트레인연구소)
  • Published : 2003.11.01
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Abstract

Variable valve timing(VVT) mechanisms are used widely for improving fuel consumption and reducing emissions. Most of application, however, are limited in the DOHC engine. Dual equal retard/advance strategy is relatively simple one and can be applied to both SOHC and DOHC engines. In this study, effects of dual equal valve timing retard/advance are investigated to observe the feasibility of VVT system on an SOHC SI engine. The result shows that fuel economy and emissions are improved in the dual retard condition due to increased internal EGR. Some amount of increase in volumetric efficiency can be achieved by advancing valve timing at low speed and by retarding at high speed. In this case, however, full load power is not so much improved as the volumetric efficiency increases because of severe knock. In the dual advance condition, there is no merit in the fuel economy and emission.

Keywords

References

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