Numerical Calibration Of Variable Valve Timing For Turbodiesel Engine

The diesel engine has been widely used in people’s life for its high thermal. However, it still needs some technology to improve the diesel engine considering the energy crisis and environment pollution. Variable valve timing technology as the effective and popular measures to solve the problems which can affect the engine’s power performance, fuel consumption and emission performance has been widely used in automotive gasoline engine. But rarely seen in diesel engine, And to gain the optimal valve timing value is still mainly rely on experimental calibration which costly and time-consuming and could not used in the diesel engine still design; In recent years, the method of numerical simulation becomes more popular. Therefore, this paper presents the study on application of variable valve timing technology in the diesel engine with the numerical simulation method.In order to determine the optimal valve timing value, we can use the engine simulation analysis methods to analysis it’s influence in some kind of diesel engine’s power performance, fuel consumption and emission performance. At the same time, this numerical simulation method could also get the optimal valve timing value’s MAP under different working conditions, which provides a feasible reference for experimental calibration. The result indicates that, intake delay angle and exhaust advance angle have a big effect on power performance and fuel consumption, valve overlap has a big effect on emission performance. High speed high and load need larger intake delay angle and exhaust advance angle to ensure power performance, at the same time, the larger valve overlap can reduce emissions. Low speed low and load need proper intake delay angle and exhaust advance angle to ensure the normal operation of diesel engine.On the basis of the engine working process calculation, we can calculate the diesel engine’s working cycle under different valve timing value and obtain transient field and its changing process in cylinder by the three-dimension simulation methods. Comparing the engine performance under the different valve timing between the engine working process calculation and the cylinder working process, we can see the similar trends even though they have some difference.