On the shift of acoustic characteristics of compression-ignited engines when operating with gasoline partially premixed combustion

[EN] As the focus of research and development is put into innovative combustion concepts with the goal of reducing harmful chemical pollutants while keeping or even improving the efficiency of conventional Diesel combustion, it is necessary to consider the impact on noise pollution brought by those innovative concepts. However, the question arises as to what extent the noise characterization and optimization strategies currently applied to conventional Diesel compression-ignited engines are applicable to these innovative combustion concepts. In this paper, we apply experimental noise characterization techniques based on pressure trace decomposition to two compression-ignited engines: a baseline conventional Diesel engine and an innovative 2-stroke engine operating with the gasoline partially premixed combustion concept. Analysis of the results reveals that the underlying physical phenomena responsible for the spectral signature of the noise are still shared between the new and the conventional concepts. However, results evince a significant change in the relevance of these physical sources, leading to necessary changes in optimization strategies for future compression-ignited engine development.