Mohammad Keshavarz - Department of Mechanical Engineering, Arsanjan Branch, Islamic Azad University, Arsanjan, Iran
Mehdi Keshavarz - Faculty of Mechanical Engineering, Khomeinishahr Branch, Islamic Azad University, Khomeinishahr, Iran

According to the world crisis about fuel consumption and environmentalconcerns regarding toxic emissions of internal combustion engines, theengines with higher efficiency and lower fuel consumption have been a topicof research in last decades. In this study, variable valve timing (VVT) andvariable length intake manifold (VLIM) techniques are used to optimize thefuel consumption of an SI engine. At first, all components of engine aremodeled in GT-POWER and a comparison with experimental results isperformed to confirm the accuracy of the model. Then, the discrete-girdalgorithm is employed to optimize the parameters in GT-POWER. The resultsobtained indicate that optimal valve timing and intake manifold lengthsignificantly reduces brake specific fuel consumption (BSFC).

Variable valve timing, Variable length intake manifold, GT-POWER, Fuel consumption, Discrete-grid algorithm