Optimisation of Diesel cold start noise

Diesel passenger cars have a substantial market share in Europe which is mainly due to their excellent performance and low fuel consumption. Also the NVH behaviour is improving core tinuously. During cold start and warm-up, however, many diesel engines still produce an un pleasantly loud knocking sound. Investigations at FEV Motorentechnik indicate that acoustic optimisation of the calibration leads to significant sound improvements without drawbacks on combustion stability and emission behaviour. The optimisation procedure is based on the engine noise prediction method CSL, developed by FEV, which is used to perform a comprehensive calibration optimisation in a DoE process.