TONAWANDA, N.Y. — General Motors Corp. will introduce a new, state-of-the-art 4.5L V-8 Duramax turbo-diesel that improves engine fuel efficiency by 25 percent, reduces CO2 emissions by 13 percent and cuts particulates and NOx emissions by at least 90 percent for North American light duty trucks and the HUMMER H2 built after 2009.
The premium V-8 diesel is expected to deliver class-leading torque, power and refinement while maintaining a significant fuel efficiency advantage over comparable-output gasoline engines.
The new dual-overhead cam, four-valve V-8 diesel engine will fit within the same space of a small-block V-8 gasoline engine. This compact size is made possible by using integral cylinder head exhaust manifolds, integral cam cover intake manifolds and a narrow block.
"This new GM light duty diesel is expected to become a favorite among customers who require excellent towing ability and fuel efficiency," said Tom Stephens, group vice president, GM Global Powertrain and Quality. "It will meet the stringent 2010 emissions standards, and it will be compliant in all 50 states, making it one of the cleanest diesel vehicles ever produced."
Environmental benefits of the new engine include a 13-percent reduction in CO2 versus gasoline engines, and at least a 90-percent reduction in particulates and NOx compared to diesel vehicles today. This will be GM’s first engine to use a selective catalytic reduction NOx aftertreatment system with a diesel particulate filter to help achieve the Tier 2 Bin 5 and LEV 2 emissions standards.
Technical highlights of the engine include aluminum cylinder heads with integrated manifolding; a variable-vane turbocharger with intercooling; a Compacted Graphite Iron (CGI) block for a stronger and lighter engine base (compared to lower-strength aluminum or heavier grey cast iron); and fracture-split main bearing caps and connecting rods for a precise fit. An electronically controlled, ultra-high-pressure, common-rail fuel system is used, which has the ability to inject fuel five times per combustion event to control noise and emissions.
"This new V-8 is not only a clean diesel meeting the toughest emissions requirements in North America, 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 other diesels on the road today, with noise and vibration performance approaching gasoline V-8 levels."
Freese said the new V-8′s compact size enables it to fit in the envelope of a gasoline small-block engine, which provides GM the flexibility to introduce this engine in a wide variety of vehicle applications should there be future market demand.
The premium V-8 diesel engine is expected to deliver class-leading refinement, horsepower and torque and fulfill multiple vehicle applications with ratings in excess of 310 horsepower and 520 lb-ft of torque.
GM (Opel, Saab, Vauxhall and GMDAT ) currently offers 17 diesel engine variants in 45 vehicle lines around the world. GM sells more than one million diesel engines annually, with products that offer a range of choices from the 1.3L four-cylinder diesel engine sold in the Opel Agila and Corsa, up to the 6.6L V-8 Duramax diesel sold in full-size vans, heavy duty pickups and medium duty trucks in the U.S.
GM first introduced the Duramax diesel 6.6L V-8 in the U.S. in the 2001 model year and since then, customer enthusiasm for this heavy duty diesel has been outstanding. In fact, GM’s heavy duty pickup truck market share has jumped nearly tenfold in the six years that Duramax engines have been offered.
Press release via General Motors