Application Of The Rapid Control Prototyping In The Development Of Engine Start-Stop Function

With the rapid change of social environment,the attention to fuel consumption and environmental problems is increasing.Engine control technology is one of the core technologies in automobile,which is closely related to automobile emission and fuel consumption.It is very important to master the rapid development technology of engine control.In this paper,the 1.5L PFI engine was taken as the research object.The software design and development of StartStop function were carried out by using the method based on model design.Based on the technology of Simulink modeling and automatic code generation,this paper developed the software from offline to online,from virtual to physical process according to the development mode of V process.The function design,strategy research,modeling,simulation,calibration and verification of the engine sensor signal acquisition and analysis,actuator control,starting function module and idling function module were carried out.Through debugging and a large number of experiments,it was shown that the rapid prototyping technology based on model design can be well applied in the software design of engine controller.Program modeling was also helpful for engineers to better carry out graphic design,to conduct early verification in the software development process,and to improve the efficiency of modeling.In this paper,the overall plan of software and hardware was designed first.Based on RapidECU and engine parts,the power supply channel,signal channel,driving channel and communication channel were established,and the ignition signal and crankshaft position signal were converted according to the actual conditions of ECU hardware,so that ECU could identify relevant signals.On the software side,starting from the chip level module library of rapid prototyping platform,this paper designed the basic module,starting module,idle speed module three modules,completed the ECU and the engine configuration,sensor signal collection and processing and output variables,the actuator interface driver module design,pump control,the main relay control,heating control module,such as oxygen start and idle speed control fuel injection and ignition module,volume,the total number of more than 50 sub modules.The function design,strategy research,modeling,simulation,calibration and verification of the engine sensor signal acquisition and analysis,actuator control,starting function module and idling function module were carried out.After the overall scheme was determined,the sub-module models were constructed and simulated.This paper focused on the attenuation control of the target air-fuel ratio and related increment in the starting process,the air volume increment in the starting process and its attenuation control to prevent the high impulse speed and the transition control of ignition advance angle from starting ignition to running ignition advance angle.In the idling control stage,the fuel oil closed loop control based on oxygen sensor was realized.By means of different main advance angle modes and relevant closed loop correction based on speed fluctuation,the calculation method and relevant correction of target idle speed were determined,and the relevant functions such as closed-loop control of idle speed gas based on speed fluctuation were realized.The application of these control strategies ensured the smooth operation of engine idling.Finally,C code was generated through the code generation tool of Simulink,and the compiler was called to generate the burn and description files.After verification of hardware in the ring and real vehicle,the engine could start quickly and entered the stable idle speed.Good results had been achieved in the transition of the hollow combustion ratio,the switch of ignition advance angle,the compensation and attenuation of air flow,and the control of idling speed during the starting process.