4.5 L V8 Duramax turbodiesel

General Motors Corp.’s revolutionary 4.5 L V8 Duramax turbodiesel, which makes its debut in Chevrolet Chevrolet Silverado and GMC Sierra light duty trucks in the 2010 model year, is compact, powerful and fuel efficient. The engine also is lighter, an important consideration in the competitive light truck market, because it was designed with more than 70 fewer parts.

The new dual-overhead cam, four-valve V8 diesel engine boasts a number of innovative design approaches that have enabled its compact size and mass, including integral aluminum cylinder head exhaust manifolds, integral cam cover intake manifolds and a narrow V-angle block. The new V8’s compact size enables it to fit within the same space of a small block V8 gasoline engine and offers GM the flexibility to introduce it in a wide variety of vehicles to meet market demand.

The new 4.5 L V8 diesel is expected to deliver more than 310 HP and 705 Nm (520 lb-ft) of torque, while delivering a 25 percent engine fuel efficiency improvement versus comparable gasoline engines.

Technical Highlights:
Robust and innovative, the new 4.5 L diesel V8’s technical details include lightweight aluminum cylinder heads with integrated manifolding; a variable-vane turbocharger with intercooling; a compacted graphite iron (CGI) cylinder block for a stronger and lighter base engine (compared to lower-strength aluminum or heavier grey cast iron); and a fracture-split main bearing cap system. GM has applied for patents on a number of these features and expects to have several patents granted before the engine launches.

Compared to typical production diesel engines, GM’s new 4.5 L V8 turbodiesel innovatively reverses the flow of air and exhaust gases entering and exiting the cylinder heads. Air enters the engine through ports in the top portion of each cylinder head. Exhaust gases exit inward between the cylinder heads and directly into a turbocharger.

“By using integral cylinder head exhaust manifolds, integral cam cover intake manifolds and a narrow cylinder block, designers saved space and reduced the engine’s weight. And because the engine makes more efficient use of heat, fuel economy and performance are enhanced, and noise and emissions are reduced,” said Gary Arvan, chief engineer for the 4.5 L V8 diesel.

An electronically controlled, 29000-psi (2000 bar) common-rail fuel system is also used on the engine. It has the ability to inject fuel five times per combustion event, reducing noise and emissions while enhancing fuel economy.

“This new V8 diesel meets the toughest emissions requirements in North America, and it also delivers an effortless performance feel because of its high torque across the speed range,” said Charlie Freese, executive director of GM Powertrain Diesel Engineering. “It is also significantly quieter than many other diesels on the road today, with noise and vibration performance approaching gasoline V8 levels.”