4XM Gasoline Engine Modeling And Real-time Model Reduction Research For Hardware In The Loop Simulation

Along with people’s continuous desire for improving the automobile performance, fueleconomy, the function of engine’s electronic control unit(ECU) is becoming more and morecomplex, the cost for ECU’s development and cost increasingly higher. In order to reduce thecosts of ECU’s development and test, as well as to accelerate the ECU’s development pace,the hardware in the loop simulation technology is gradually being introduced fordevelopment and test of the ECU’s function.As for the hardware in the loop simulation, we usually use plant simulation model forthe ECU’s function test through real-time communication with tested ECU in the loop. Inorder to ensure the accuracy and feasibility of the ECU’s test, the plant model should meetthe requirements of accuracy and online calculation speed. Therefore, the establishment ofan accurate plant model and real-time model reduction has become a crucial step duringhardware in the loop simulation process.The research was carried out based on4XM naturally aspirated PFI gasoline engine andcan be roughly divided into three parts:4XM gasoline engine modeling, engine model’sreal-time reduction for hardware in the loop simulation and the reduced gasoline enginemodel’s real-time validation.1)4XM gasoline engine model has been established based on the AMESim softwareplatform, parameter configuration and adjust were completed. Select a total of39operation points:13engine speed points within1200~6000r/min and3load rate of low,medium and high for every speed point. Compared with test data of intake air mass flowrate, output torque, fuel consumption per hour, complete the validation of the model.Verification results show that the inlet air mass flow rate relative error within10%, theoutput torque and fuel consumption per hour relative error within5%,4XM enginemodel can meet the requirements of accuracy. But model is too complex, cannot meet theonline calculation speed for the hardware in loop simulation, So4XM engine model should be reduced for real-time simulation.2)4XM engine model real-time reduction for the application and model validation ofhardware in the loop simulation. Analyze each subsystem’s reduction potential of4XMgasoline engine, puts forward reduction process mainly towards the engine’s complexintake and exhaust system. Model reduction process can be divided into two steps:①Integration of the intake and exhaust system components according to the components’characteristics (capacity, resistance and inertia), so as to reduce the number of differentialequation that not sensitive to the simulation results;②Frequency analysis ofcharacteristic intake and exhaust system components, so as to reduce the order ofalgebraic differential equations. So the model can be simulated in a larger simulation stepunder the condition of original feature’s little loss of the system, which can significantlyreduce the calculation time.0.1ms fixed time step calculation using Euler solver for thesimplified model validation. Compared with the complex model, simplified model’srelative error of intake air mass flow rate, output torque, fuel consumption per hourincreased by8%,8%and5%respectively, The reduced model can still meet the accuracyrequirements of the hardware in the loop simulation.3) Reduced4XM gasoline engine model’s real-time validation. Using dSPACE hardware inthe loop simulation platform (DS1006processor, quad-core2.8GHz) for onlinesimulation of reduced4XM gasoline engine model and the turnaround time is between0.02and0.03ms, less than sample time of0.1ms. So the reduced model can meet theonline simulation requirements of hardware in loop simulation, and allows forimprovements of model accuracy and input/output interface’s configuration.In conclusion, the proposed method for gasoline engine modeling and real-time modelreduction is effective and feasible, and can be used for gasoline engine’s modeling andmodel reduction research for hardware in the loop simulation.