Prediction of Camshaft Torque and Timing Chain Load for Turbo Direct Injection Diesel Engine

The fluctuation of the crankshaft rotational speed of a turbo supercharged direct-injection diesel (hereafter called i-CTDi) engine is large, causing the timing chain load and the valve train driving torque to increase.

To overcome this, a simulation method that enables the timing chain load and the valve train driving torque to be predicted while taking account of the fluctuation of the crankshaft rotational speed was established. In this simulation, all of the moving parts centered about the crankshaft were coupled, and an engine in a working condition was faithfully constructed in the computer. In the construction of the model, the issue of the conflicting topics of securing accuracy and reducing computing time was solved by looking at the frequency response of each part and adopting a simple model.

As a result, it was possible to predict both the timing chain load and the valve train driving torque with high accuracy and in a short time. Also, this virtual engine was able to contribute to the optimum design of the actual valve train and timing chain.