Numerical Investigation of the Effect of Knock on Heat Transfer in a Turbocharged Spark Ignition Engine

Abstract

This investigation deals with the EF7 (TC) engine, a dual fuel engine equipped with a turbocharger system, consequently with a high probability of knock inception. In this study, an operating cycle of the engine was simulated using KIVA3V code. Some modifications were carried out on the KIVA method of calculating pressure in the intake port in order to simulate turbocharger pressure correctly. Autoignition and knock were then simulated using the autoignition integral model. The modified code and the simulation were verified using three different methods; incylinder average pressure, gas temperature of the exhaust port, and autoignition timing. The simulation results using the autoignition integral model, as compared with the experimental data, proved to be reasonably accurate. Following this validation, the effect of the knock phenomenon on the engine heat transfer through the walls was investigated. The simulations showed that the rate of heat transfer through the walls under knocking conditions is about 2.2 times higher than that under normal conditions. However, it was also shown that the total heat transfer increases about 15%.