Experimental Reduction of Combustion Noise at Idle Speed in a Single Cylinder CRDI Diesel Engine BT Optimizing the Fuel Injection Pressure

The design and development of modern internal combustion engines are 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. Additionally, customer requirements for combustion noise need to be met, which can be accomplished through optimization of the combustion system. For a long time now, the reduction of noise and vibration is one of the major concerns of carmakers for their Diesel engines. Cold and idle conditions are considered to be the most critical conditions for both combustion noise and pollutant emissions. These goals can be met through the development of advanced combustion systems and the increased flexibility of fuel injection systems and ECUs. This report presents the results of a study about the effects of Fuel Injection Pressure on the combustion process and on the combustion noise at the idle condition in a Single Cylinder CRDi Engine.