The potential for soot and CO reduction in direct injection diesel engines for passenger cars

As part of the FVV project “The Potential for Soot and CO Reduction for Preventing an Increase in CO Emissions in Direct Injection Diesel Engines with Flexible High-Pressure Direct Injection for Passenger Cars,” a 3-step CO model was created at the Institute for Combustion Engines (VKA) on the basis of extensive kinetic calculations and integrated into the CFD code KIVA and the FVV GPA multi-zone combustion model. To verify the model and as a basis for the CFD simulation, the gas temperature and the concentration of the species CO, O2 and soot were measured during combustion in an optically accessible engine by means of a rapid gas-sampling valve and laser-optical measuring methods. For this purpose, starting from a basic operating point, the start of injection, the rate of exhaust gas recirculation and the rail pressure were varied. The results gained from this test provide an explanation for the soot / CO conflict in diesel engines with advanced injection strategies.