Reducing Combustion Noise

The design and development of modern internal combustion engines is marked by a reduction in exhaust gas emissions and increase in specific power and torque. Correspondingly, combustion noise excitation and fuel consumption also have to be reduced. These objectives can be achieved through the development of advanced combustion systems, the increased flexibility of fuel injection systems and ECUs. However, development of modern combustion systems and vehicle applications has become increasingly complex. Creating an exact, yet straightforward description of combustion noise is a very important task. The customer’s subjective impression of the entire vehicle, regarding items such as diesel knock sensitivity, provides evidence to support its value. FEV has developed a modern method to describe combustion noise excitation using the in-cylinder pressure-based FEV CSL (Combustion Sound Level) tool. This tool provides the potential to completely investigate the NVH calibration, while meeting the targets for emissions and fuel consumption. FEV CSL-CAL (Combustion Sound Level – Calibration) is a tool FEV specifically developed for NVH-related vehicle calibration. These tools enable all of the important ECU parameters to be optimized simultaneously under the customer-relevant driving conditions. The optimal calibration map for steady-state as well as for cold start and during acceleration is created from by FEV SQO (Sound Quality Objective) tool that develops the parameters used to subjectively judge combustion noise. These tools provide a complete description of the combustion noise, which allows it to be optimized towards the expectations of the customer.