Gm’s New High-Tech Diesel V-8
General Motors has just unveiled a new diesel V-8. Actually it’s newer than new, as it will not be offered in GM vehicles until after 2009, the automaker says. However, the engine is well worth a look right now for two reasons. First, it signals GM’s growing commitment to diesel-powered private vehicles for North American consumers. Next, the 4.5L Duramax Light Duty V-8 is unlike any American V-8 you have seen before.
The latest Duramax Diesel is built on a 72-degree bank angle, instead of the nearly universal 90-degree angle used on American V-8s in modern times. Also, the engine’s flow pattern is reversed: Here, the intake manifolds are on the outsides of the cylinder heads, while the exhaust manifolds, which are integral to the cylinder heads, are in the middle of the V. A variable-vane turbocharger and intercooler are nestled down between the heads. The block is compacted graphite iron (CGI), while the heads are cast in aluminum to reduce weight.
These features give the new engine an unusually small, light, and narrow form factor for a diesel, with the ability to fit anywhere the current LS-series gasoline V-8 will go, according to GM sources. Potential applications mentioned so far include pickup trucks under 8,600 pounds GVW and the Hummer H2. While no passenger-car plans have been revealed so far, the new engine’s small footprint allows GM “the flexibility to introduce this engine in a wide variety of vehicle applications should there be future market demand,” according to GM statements. [And what a potential hot rod engine swap candidate! -Ed.
Displacing 4.5 liters and featuring a double-overhead-cam four-valve layout, the new diesel meets the tough emissions standards due in 2010, achieving a 13 percent reduction in carbon dioxide compared to gasoline engines and a 90 percent reduction in particulates and oxides of nitrogen over current diesels. An ultra-high-pressure, common-rail fuel-injection system can inject fuel up to five times per combustion event for precise noise and emissions control. However, just to show how times have changed, no power or torque figures have been announced as yet. “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,” says 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.” -Bill McGuire
Photo Gallery: Chevy Duramax Diesel Engine - Inside The OES - Hot Rod Magazine
