Powerful, Clean Yet Silent

Internal combustion engine development nowadays is characterized by decrease of exhaust gas emissions and increase of specific power and torque. Combustion noise excitation and fuel consumption have to be decreased in parallel. All these goals can be met today due to the development of advanced combustion systems and the increased flexibility of fuel injection system and ECU. But hereby, combustion system development and vehicle application have become more complex in recent times. A precise and simple description of ‘combustion noise’ is not trivial in this context. The customer subjective impression of e.g. diesel knock intensity, at vehicle interior and exterior, is the relevant value for this. Combustion noise excitation today is described by using the in-cylinder pressure based FEV CSL. Full calibration NVH potential is explored hereby, while meeting the emission and fuel consumption targets. FEV CSL-CAL is the in-house developed tool for NVH related vehicle calibration. All important ECU parameters are optimized simultaneous under the customer-relevant driving conditions hereby. Additionally, sound quality objective parameters for judgment of subjective combustion noise impression — FEV SQO — are used to find the optimal calibration map, for steady state as well as for cold start and during acceleration. By all this, combustion noise is described well and can be optimized toward customer expectation.