Effects of cold start control strategy on cold start performance of the diesel engine based on a comprehensive preheat diesel engine model

It is really vital for the diesel engine to achieve a fast cold startup under low temperature environment especially in alpine region with the winter temperature in the range of -30 degrees C to 0 degrees C. The development of diesel engine cold start-up research is under the limits of the test equipments and the funds. In order to explore the cold start ability of diesel engine, the simulation and experiment were attributed to be combined on the basis of previous research methods in this work with a comprehensive consideration of low temperature, atmospheric pressure, preheating effect et al. The related low-temperature dependent maps (preheat time, running speed, torque and so on) were made by simulations for specific engine and then have been loaded down to the ECU (Electronic Control Unit) and the vehicle experiments were carried outdoor of Heihe site in China. The results indicate that the maps with preheat function simulated by using detailed engine parameters can achieve the requirements of the cold start under the low temperature range (-25.5 degrees C to -16 degrees C). Preheat time, start voltage and start duration are employed to investigate the cold start ability for the diesel engine, which provide a better reference for strengthening the cold start capacity research. The longest preheat time is 10 s longer than the shortest warm-up time which can increased the intake temperature directly. The cold start-voltage drops by 15% as the temperature drops by 9.5 degrees C which tends to decrease with the temperature reduce.