Development and Validation of a Variable Displacement Variable Compression Ratio Miller Cycle Technology on an Automotive Gasoline Engine

At partial load, traditional automotive gasoline engines have high pumping losses due to the throttling of intake charge for load control. Variable Valve Timing (VVT) and introduction externally cooled EGR could reduce but only with a very limited effect. On other hand, in medium full range, engine cannot utilize compression ratio limitations knocking. A variable displacement, device which utilizes an asymmetric camshaft realize different closure times two valves is discussed this paper. The large-scale change valve timing leads effective cylinder volume at closure, realizes ratio. utilized increase in-cylinder thermal efficiency same time. Engine dyno test results indicate that, low later volume, pressure be significantly increased, therefore reduced. However, reduced would lead reduction (ECR) drop efficiency. Therefore, there balance point between loss side, when avoiding knocking becomes major controlling factor combustion phasing (degree constant-volume combustion) expansion (EER), too significant EER also exists best compromise ECR EER, system one moderate as possible. quantitative equations include both calculations captured above observations pretty well can optimize IVC, EVO, ECR, performances during concept stage and/or calibration engine.