Air System and Diesel Combustion Model for a 4 Cylinder Engine in Real Time Computing Conditions: Application on a EU5 Personal Car with Diesel Particulate Filter

摘要

In an industrial context, close to the start of production and development of Engine Control Unit (ECU) systems, it is necessary to validate the complete dataset of the application and thus, to run software tests on a real ECU which is connected to a closed loop HIL Test bench. In the field of application for the simulation of dataset and the reduction of real vehicle tests, it is required to simulate an engine behavior in terms of mixture mass and energy flow rate, temperature and pressure. The aim of this work is to reproduce this engine behavior with a focus on combustion process and component simulation models, Oxidation Catalyst (OxiCat) and Diesel Particulate Filter (DPF). A model has been developed with the help of experimental data extracted from an Original Equipment Manufacturer (OEM) engine project. The experimental data available from the motor test bench (injected fuel mass, air flow, temperature, pressure, air-fuel ratio λ, ...) and the OEM geometrical data, serve as calibration data and parameterization for the model. A physical study of each component of the air system has been performed. The discharge coefficients, the efficiencies and heat transfers are defined and modeled according to the operating conditions for the air filter box, turbocharger, charge air cooler, throttle valve, intake and exhaust manifolds, EGR valve, turbine (including torques on the shaft), OxiCat and DPF. Additionally, combustion models have been developed to simulate the influence of the injection strategy (pre, main, post and late injections) on the exhaust temperature and the pollutants emissions, which are taken into consideration in the exothermal reactions inside OxiCat and DPF. The results show that the model prediction in term of pressure, and temperature are in good accuracy with the OEM project data. The aftertreatment temperature behaviors in the OxiCat and DPF are well reproduced by the model. It allows the engine management department to test all ECU software strategies, including the activation of diagnostics, and validated on a closed loop HIL Test Bench with the developed engine simulation model. According to overall environmental conditions (ambient temperature, atmospheric pressure, road shape,...) non regression tests are also possible to check any deviation of engine behavior over the simulated driving cycle in comparison with a real car behavior.