Comprehensive Combustion Noise Optimization

Combustion noise plays a considerable role in the acoustic tuning of gasoline and diesel engines. Even though noise levels of modern diesel engines reach extremely low values, they are still higher than those of conventional gasoline engines. On the other hand, new combustion procedures designed to improve fuel consumption lead to elevated combustion noise excitations as in case of today's direct injecting gasoline engines whose vibration excitation and airborne noise emissions are slightly increased during stratified operation. The partly conflicting development goals resulting from this can only be realized by integrating the NVH specialists' expertise into every development step from concept to SOP. Through these interdisciplinary design efforts, gasoline engines will maintain their favorable acoustic properties while achieving low fuel consumption levels similar to those of diesel engines, whereas one driving ambition behind modern diesel engine design efforts is to create a “gasoline engine sound”.