Powertrain NVH Optimization of Single Cylinder CI Engine

With increasing pursuit for comfort in mobility NVH characteristics are becoming more important than ever. Achieving a benchmark beating NVH behavior involves optimizing source, transfer paths as well as target location mechanical characteristics. In ICE vehicles, powertrain accounts for major source of noise and vibration. This work encompasses NVH refinement strategies for a single cylinder compression ignition engine. The work starts with setting target values for NVH characteristics based on competitive benchmark data analysis. A complete development strategy involving extensive testing and CAE correlation is presented here. Contribution analysis in component level for optimization of NVH behavior is carried out employing NVH testing in anechoic chamber supported by CAE simulations.

This paper describes the later phases of the entire development process which are decisive for engine NVH; the combustion and mechanical development phase and the NVH development and refinement phase. In order optimize engine acoustical performance, experimental identification and localization of noise sources were performed at different speed and load. Correlation of noise to structural vibrations and resonances were established and design matured using simulation and proved with experimental validation to achieve the set targets. Deep down analysis of various powertrain components was done to reduce source noise and vibrations. CAE models were created for design optimizations which were validated using test results. Force analysis was performed, and balancer shaft was designed to reduced inertial forces causing vibration as net unbalanced forces are always a concern in single cylinder engines. Finally complete validation of the powertrain accommodating all the optimizations is done in semi anechoic testbench as well as in vehicle.