System for controlling the combustion noise a motor vehicle diesel engine

A system of controlling the combustion noise of a motor vehicle diesel engine, the engine being of the type including feeding means for feeding each of its cylinders with multiple injections of fuel, and adapted to trigger fuel feed to each cylinder using at least one pilot injection followed by a main injection of fuel, wherein the system comprises:

• means for determining pressure gradients in the cylinder of the engine while it is in operation, at least during the pilot and main injection stages;
• and
• means for determining the quantity of fuel to be injected into the cylinder during pilot injection for a predetermined quantity of fuel to be injected during main injection so as to optimize an operating criterion of the cylinder based on the ratio between the pressure gradients corresponding to the pilot and main injection stages, and thus optimize the operating noise of the engine.