Unique Cold Start Method Used on Volvo's New 12L Unit Injector Diesel Engine

Volvo Truck Corporation has developed a new cold-start method for heavy duty engines. The background for this new method is to get a high cold-start quality, at a low product cost for the customer.

This paper describes the development of the new cold-start method, the layout for the system and the start procedure in low ambient temperature.

The basic element for this start principle is to increase the temperature in the combustion chamber before the combustion begins.

The tools for achieving higher temperature are the following:

• Precranking a number of revolutions without fuel injection.
• Produce a back-pressure in the exhaust pipe to reduce the gas exchange and decrease the loss of heat in the combustion chamber.

Volvo Truck Corporation uses the new cold-start method in production of the D12 engine.