Performance simulation of a four-stroke engine with variable stroke-length and compression ratio

The engine consists of a coupled four-bar, slider-crank and inverted slider-crank mechanisms. The variations in stroke length and compression ratio are obtained through varying the location of the pivot of the four-bar rocker arm. The engine power characteristics are based on the power cycle of the piston inside the cylinder. Several pivot locations are considered giving a range of stroke lengths and corresponding compression ratios. A simulation model is developed and verified with experimental results from the literature for both constant and variable-stroke engines. The simulation results clearly indicate the advantages and utility of variable-stroke engines in fuel-economy issues.