Increased Internal Combustion Engine Efficiency with Optimized Valve Timings in Extended Stroke Operation

Spark-ignited internal combustion engines are known to exhibit a decreased brake efficiency in part-load operation. Similarly cylinder deactivation, the x-stroke operation presented this paper is an adjustable form of skip-cycle It effective measure increase engine, which has be equipped with variable valve train enable feature. This presents optimization procedure for exhaust timings applicable any valid stroke number greater than four. In first part, gas spring operation, during all exchange valves closed, explained, as well how it affects indicated and blow-by mass flow. second simulation model timings, parameterized measurement data obtained on engine test, used find optimal timings. We show that 12-stroke load 5 Nm, 34.3% achieved. Preloading residual prevents oil suction thus helps reduce hydrocarbon emissions. Measurements variations 4-, 8-, operations by applying remains high center range significantly lower torque outputs.