Big efforts in diesel engine development are necessary to meet increasingly stringent future emission regulations. A very efficient and promising approach to rapidly improve the pollutant emission behaviour of the existing vehicle fleet is to optimise the diesel fuel composition with regard to reduced pollutant formation. That is why an European research program was carried out to evaluate the potential of an optimised fuel composition. 12 diesel-like fuels were composed performing lower aromatic concentrations and containing oxygenating components. A series-like modern passenger car CR DI diesel engine was operated on a test bench under various steady state conditions using these fuels and - for comparison - a diesel-typical reference fuel. Pollutant concentrations have been measured in the tail pipe and in-cylinder, using a fast-timed gas sampling valve with high temporal resolution. To get further information on the transient pollutant emission behaviour of the engine the investigations were extended by vehicle tests (same engine) on a chassis dynamometer. For all experiments the HC, CO, CO2, NOx, O2 and PM concentrations in-cylinder and in the tail pipe were measured. Furthermore a differentiated HC and particulate analysis was performed and the particulate size distribution was determined. (A)
Abstract