Estimation of Performance Characteristics of a Split Cycle Based SI Engine

Increasing fuel efficiency of automobile engines has become a prime motive, as the fossil fuel reserves are limited. This has forced automakers to look into technologies that help utilising the available reserves effectively. A typical three cylinder engine at urban driving speed devours more fuel developing excess power than required. Fuel cutoff is a technique that minimises the excess fuel being burnt. The present work concentrates on performance characteristics obtained by integrating Scuderi Split Cycle concept with Spark Ignited (SI) engine that employs fuel cutoff technology. In the current numerical investigation, performance characteristics of a three cylinder SI engine (used in Volkswagen Polo car) was estimated by extrapolating the results obtained for single cylinder using commercially available Ricardo VECTIS tool. The simulation results are validated against analytical results ascertained in concern to engine working volume and compression ratio. The conceptual model that utilises the abandoned cylinder to supercharge the variable displacement engine is simulated to determine the enhancement in performance characteristics. The variable displacement SI engine of a small sized passenger car was found to reduce 33% of fuel consumption and also satisfied the required road load condition for lower operating speeds. Implementation of the Scuderi split cycle concept in variable displacement SI engine supercharge the quality of intake air and improved the performance characteristics substantially by 5% with the same amount of fuel supplied.