| Oil and gas separator is a key component in the Positive Crankcase Ventilation System,which can realize the separation of the oil mist from blow-by gas,thus reduce the oil content of the blow-by gas into the air intake system,and its performance has a significant impact on emissions and engine reliability.The low separation efficiency of the oil and gas separator poses the following problems: The secondary combustion of the oil mist increases the amount of particulates in the original machine emissions;the mist in blow-by gas may pollute the air intake system,and reduce the life of the supercharger for supercharged engine;the combustion of oil mist in the cylinder results in carbon deposition,affects the reliability of the machine,and causes oil consumption increases of the whole engine.In order to avoid the above problems,this paper designs the active control system of the Complex Oil-gas Separator for the requirements of Pressure Control Valve system and the active control system,improves the efficiency of the oil and gas separator in whole working condition,reduces the pressure loss of the Pressure Control Valve system and reduces the fluctuation of crankcase pressure in the alternating working condition.Based on the deep study of the characteristics of engine blow-by and the pressure characteristics of crankcase,the design of the active control system and the hardware and software of the Complex oil and gas separator control system are carried out,and the experimental verification.The specific work is as follows:1)In view of the function of Pressure Control Valve system,the layout of the prevailing structure was analyzed in detail.The characteristics of the engine blow-by gas and the pressure characteristics of the crankcase were studied in depth.The changes in the flow rate and range of crankcase pressure with the engine conditions were learned.The structural design of the Pressure Control Valve system with the Complex Oil-gas Separator and the electromagnetic check valve was carried out.2)Infineon XC2765 X has been taken as the core controller of Complex Oil-gas Separator control system,pin assignment was done according to the resources of control chip.Taking advantages of on-chip resources of Infineon XC2765 X,this paper has designed the hardware circuit,including power supply module,reset circuit,debugging module,signal acquisition and conditioning,drive output and CAN communication,ensure that the hardware system could fully meet the development needs of complex oil and gas separator active control system.According to the system requirements,select the appropriate sensor and actuator devices.3)With the help of Infineon’s DAv E visualization configuration software and TASKING compiling software,the overall software platform design for the active control system of the Complex Oil and Gas Separator was carried out.The development and implementation of system control strategy were made,including the starting conditions,normal working conditions and impeller cleaning,fault detection and so on.According to the speed / load map,the speed of the active part motor is controlled to realize the optimal efficiency of oil and gas separation.Through the control of electromagnetic check valve opening and closing on the piping line,regulate the flow of crankcase blow-by,and achieve the crankcase pressure control to ensure that the crankcase pressure is within a reasonable range.4)The performance test bench and the engine test bench of the Complex Oil and Gas Separator were set up,and the two-level functional verification test of the oil-gas separator control system was completed.The performance test platform of the oil and gas separator performed the verification of the control function of the control system pulse signal acquisition and the signal on-demand output,As well as analog signal acquisition and relay control signal output.Oil and Gas Separator engine bench test mainly carried out the function verification of oil and gas separation,and the functional verification of crankcase pressure control.The experiments proved that the separation efficiency and crankcase pressure control are in line with the needs of Pressure Control Valve system. |
