Combined WAVE-Simulink simulation to predict the exhaust emissions during an ECE-40 homologation cycle for a CVT vehicle

Abstract The purpose of this study is to create and develop a flexible simulating tool that allows to couple the simulation of the engine, performed by means of a 1-D computer-aided engineering code (WAVE, Ricardo Software), along with the dynamic simulation of the whole vehicle on which the engine is installed. The dynamic model of the vehicle (a scooter with CVT transmission) is realized with Simulink (a MATLAB toolbox), and is schematized as a rigid body subjected to the engine force, aerodynamics forces, tyres friction forces with an equivalent mass which is the sum of the vehicle mass and the rotating equivalent mass. A complete Simulink model of the CVT transmission is realized too. In the present work the authors want to provide a general methodology that permits to numerically evaluate the performance, the operating conditions and exhaust emissions of an engine once it is installed on a given vehicle. In particular, an important application of this work is the simulation of the ECE-40 homologation cycle for a CVT motor vehicle. Two-wheels vehicles, in fact, are compulsorily subjected to an homologation test established by the EU directive 2002/51/CE in order to verify that the pollutant emissions are under the imposed limits. This test is performed experimentally by putting the vehicle on a roller bench that reproduces the functioning of the motorcycle in urban and extra-urban driving conditions. The virtual approach permits to reduce the number of experimental tests that have to be performed in order to achieve the results both in terms of pollutant emissions and global performance.