Optimization Of Diesel Engine Performance And Design Of A Cold Start Coupling System At Low Temperature

As a high efficiency power equipment,diesel engine has been widely used in various domestic engineering fields and military equipment related to national security.However,under low temperature environment,the performance of cold starting ability,working stability and fuel economy of diesel engine is not good.Due to the vast geographical area in China,the land area with severe winter temperature accounts for a large proportion.Some emergency equipment,emergency vehicles and other special equipment require the diesel engine to have good starting performance and stable and efficient operation under the extremely cold condition of-41 ℃.Therefore,it is a hot topic to optimize the performance of diesel engine at low temperature.This article analyzes the main factors that affect the operation of diesel engines under low temperature conditions,the optimization of diesel engine performance,and the main methods to improve the cold start capability of diesel engines.Then the simulation optimization analysis of the diesel engine performance at low temperature and the design of the cold start coupling system are carried out.The main research contents are as follows:Firstly,the working process and principle of four-stroke diesel engine are analyzed.According to the basic assumption,the working medium state of the four-stroke diesel engine can be expressed by three basic parameters(p/T/m).The performance simulation model and cold start simulation model of diesel engine are established by using GT-POWER simulation software,the simulation calculation value is obtained by inputting the initial control parameters,and the accuracy of the model is checked by comparing the calculated simulation value with the factory value of diesel engine.Secondly,the performance simulation optimization analysis and cold start simulation analysis of diesel engine are carried out by using the established simulation model.The optimum injection advance Angle,injection pressure,inlet valve opening Angle and exhaust valve opening Angle of the target diesel engine were obtained through performance optimization simulation at low temperature.Through the simulation of cold starting,some Suggestions for improving the cold starting ability of the target diesel engine are obtained.Then a battery incubator was designed for the battery bank and the insulation experiment was carried out.The reasonable insulation layer thickness and the corresponding insulation time were obtained.For the special case that the battery cannot be used normally due to the low temperature,an emergency heating device was designed to produce heat by the reaction of quicklime and water,the emergency device can be used for emergency heating of battery and diesel engine.Finally,in order to solve the problem of diesel engine cold start under extremely low temperature conditions,the diesel engine cold start coupling system is designed in this paper based on battery insulation device,emergency heating device,PTC intake air preheater,cooling water heater and diesel engine control panel.After the commissioning was completed,a preliminary experiment was carried out on the entire system.The test found that the cold start coupling system can operate normally,which laid the foundation for the subsequent cold start test of the diesel engine in the field.