Combined Compensation Strategy for the Minimization of the Pollutant Emission of GDI Engines Under Variable Atmospheric Conditions

The present and the future legislation norms require increasingly the compliance of strict limits concerning the pollutant emissions of internal combustion engines. According to the usual standards, the measured engine performances are normalized to defined atmospheric conditions.

However, the variation of the atmospheric conditions implicates a modification of the thermodynamical and chemical processes during the mixture formation and combustion. The standards take these modifications only indirectly into account in a passive mode without any active correction.

The paper presents the results of analysis of the effects of different atmospheric conditions (as pressure, temperature or humidity) on the internal processes of a four-stroke four-valve research engine working with direct injection when using a specially developed integrated sensor for the simultaneous measurement of the atmospheric parameters. Based on this analysis, a strategy for compensation of the torque variation as well as of the emission behavior and specific fuel consumption of the engine in a wide load and speed range has been developed.

The result of the combined active compensation strategy show especially a remarkable potential for the minimization of the pollutant emission under various atmospheric conditions.