Design And Research Of Engine Cold Start Loading Device

The cold start performance of the engine is one of its important performance indicators,it not only affects the efficiency of the engine,but also affect the engine crank link and valve service life.If the engine can not be started in the cold or not easy to start,not only will increase the fuel consumption,the starter overheating,but also make the discharge of pollutants and battery life shortened,so the engine low temperature cold start technology to improve the use of motor vehicles There’s important meaning.In order to study the cold start of the engine,this paper designs the cold start loading device of the engine in the low temperature box,and can carry out the cold start test with load.The main contents of this paper are as follows:Based on the research status of the cold start of the engine at home and abroad,the experimental scheme of the cold start loading of the engine in the low temperature box is put forward and the necessity of the experiment of low temperature cold start loading is analyzed.According to the characteristics of the engine cold start conditions,the engine cold start process dynamic analysis,on the basis of the establishment of the engine cold start model.According to the characteristics of the engine cold start spindle force,to determine the engine cold start loading program.The working principle of the engine cold start loading device is introduced,and the key components are selected and designed,and the engine cold start loading device is designed according to the experimental scheme.The hydraulic system of the engine cold start loading device is modeled by the power bonding graph method.According to the structure and characteristics of the proportional valve,the mechanical equation is established,and the mathematical model of the proportional valve is obtained by Laplace transform.The whole hydraulic system is simulated and analyzed.According to the simulation results,the mechanical equation of the proportional valve and the characteristics of the secondary components,the reason of the device loading fluctuation is analyzed and the accuracy and stability of the device loading are obtained after optimizing the parameters such as the quality of the main spool and adding the accumulator Ascension.The overall structure of the engine cold start loading device is designed.The vibration of the device is analyzed,and the excitation force,the excitation frequency and the transfer rule of the loading system are obtained.The static analysis and modal analysis of the loading trolley,which is directly related to the generation,transmission and engine operating conditions of the loading force,provide the basis for the use of the device in different scenes.In the low temperature box carried out the engine cold start loading experiment,design test program,get the engine at different temperatures cold start situation.Combined with the experimental data to verify the feasibility of the engine cold start loading test program and the design of the device and the rationality of the analysis.