General Motor's long awaited new diesel truck engine is in production and being shipped to dealers. This 6.6 litre engine, available in GM's heavy-duty 2500 and 3500 series trucks, is built in Moraine, Ohio, as a joint venture between GM and Isuzu. Trying to recapture some of the diesel truck market from Ford and Chrysler, the Duramax engine sets new standards for the light-duty truck market. Here is how it achieves that. The V8 Duramax engine uses a direct-injected, common rail fuel system.
Direct injection is a type of diesel injection where the fuel is sprayed directly into the cylinder.
GM's last diesel engine design used pre-cup injection, where the fuel is sprayed into a small chamber that leads to the cylinder. The direct injection design of the Duramax is noisier but GM is using pilot injection control to reduce engine noise. Pilot injection is where a small amount of fuel is injected into the cylinder several degrees before the main fuel injection occurs. Pilot injection creates slight pressure in the cylinder to help the rings seal against the cylinder wall and push the piston toward the thrust or power side of the cylinder. This makes the engine operate much quieter and more efficiently.