Influence of intake valve closure angle on IC engine indicated parameters

The paper presents results of modelling study of influence of an intake valve closure angle on IC engine indicated parameters. The modelled engine was Andoria S231, which was working on methane. At first, optimizations of the model were done by comparison of the indicated mean effective pressure for real engine and modelled engine. Next, modelling was done for early intake valve closure angle in comparison to original closure angle. The engine was simulated as a naturally aspirated one and for the cases such indicated; parameters as indicated efficiency, mean indicated pressure, fuel consumption were calculated. During the modelling ignition, timing and air-fuel ratio were fixed. For better comparison for two cases of early intake valve closure angle the engine was modelled as super-charged one where mean indicated pressure was fixed at the same level as for the naturally aspirated engine working with original valve timing and indicated parameters were calculated and compared with in parameters determined from this naturally aspirated engine. Because of the calculations, characteristics of indicated parameters vs. intake valve closure angle were computed. As a result of this research, both the decrease in indicated efficiency, indicated mean effective pressure were shown, temperature of fresh charge, end of compression stroke and maximum in-cylinder temperature were observed for naturally aspirated engine with early intake valve closure angle