Modelling Methodology of a Spark-Ignition Engine and Experimental Validation: Part II: Gas Exchange Process 2002-01-2194

This paper presents an optimized methodology for the development and calibration of a 1D pipe system model of a spark-ignition engine, the procedure has been also experimentally validated.

From experimental tests in a steady flow rig and using data from different sources, the following pressure loss coefficients are determined: effective area of the filter, discharge coefficients of the throttle valve, plenum-runner interface and cylinder valve ports. As a particular improvement, a new formula is developed to allow the pressure loss in pipe bends to be concentrated in an initial or final pipe section.

Synchronized measurements of unsteady pressure, flow velocity and temperature, with appropriate time resolution in different points of the intake and exhaust manifolds, have been accomplished. Different engine regimes are analysed and experimental measurements are obtained.

Finally, a full comparison is made of the experimental and numerical results using the simple 1D model developed, and an analysis of the model capacity to predict the real flow measured in the test engine is carried out.