Research On The Hardware-in-the-loop Simulation System For ECU Of LNG Engine

With the continuous consumption of fossil fuels and automobile exhaustgases pollution more and more serious, it is an urgent need to find new energysources to replace the traditional automobile fuel. LNG, the ideal vehicle fuel，has the advantages of high energy density, low storage pressure, clean exhaustgas, etc. Without changing the structure of original engines, original enginecan be transformed into LNG engine through designing and developing fuelsupply system，ignition system and engine ECU. LNG vehicles have goodprospects for development, but engine ECU is a nuclear component of engine,the reliability of hardware and software will directly affect the stability ofengine and operation safety of vehicle. At present, the development of engineECU is high cost and difficult. Moreover, with more and more requirements ofvehicle performance, the development of engine ECU has become morecomplex and difficult. To solve the above problems, this paper presents engineECU hardware-in-the-loop simulation system(HILSS). This system can greatlysave labor, material and financial resources, shorten the cycle, reduce the riskof development. It is an ideal tool for the development of engine ECU. After thoroughly researching on domestic and foreign engine ECUHILSS, a new scheme has been proposed to achieve the automatic test forLNG engine ECU by designing new hardware and software of HILSS. Theupper PC runs the real-time simulation model of LNG engine and monitoringsystem. Simulation ECU transmits signals between engine ECU and host PCvia CAN bus.(1) Freescale MC9S12XEP100is used as MCU for the simulation ECU.According to the function requirements, peripheral circuits of simulation ECUhave been designed in this paper. Simulation ECU can receive sensor signalsfrom upper PC via CAN bus, and convert them into the input signals which issuitable for the normal operation of the engine ECU. At the same time,simulation ECU collects the output signals of engine ECU and uploads them tothe upper PC to achieve the closed-loop test of system.(2) Monitoring system of upper PC is programmed by LabVIEW2012. Inorder to realize the real-time of system, multi-thread programming technologyhas been adopted. Monitoring system can display real-time dynamicparameters of engine operation, store data and modify operation parametersonline.(3) Based on the research of the simulation model of gasoline engine,mean value simulation model of gas engine is established byMATLAB/Simulink. Simulation model of engine is encapsulated into DLLfiles to improve the real-time of system. (4) Design of CAN bus communication is divided into two parts,including the communication of simulation ECU and upper PC. To thesimulation ECU, it needs to program for MSCAN model. Upper PC callsstandard library of USB-CAN to communicate with simulation ECU via CANbus.