GM Engineers Design NEW 4.5L Duramax Turbo Diesel V8
Just finished reading an article in Automotive News about GM's new 4.5L Duramax turbo-diesel V8. It has a double overhead cam design with four valves per cylinder. It will develop at least 310hp and 520lb-ft of torque. It will be sold in all 50 states and will be the first GM engine that will use urea injection to control emissions of oxides of nitrogen (NOx).
According to the article, the engine's design reverses the flow of air and exhaust gases going in and out of the cylinder heads. On standard V8 engines, fuel and air enter on the side of the cylinder heads facing the inner part of the "V." The exhaust gases exit on the V's outside. In the new design, air enters the engine through ports in the outer portion of each cylinder head. The exhaust gases then exit inward between the cylinder heads and directly into a turbocharger.
They say this eliminates numerous parts, saves space and lets the engine make more efficient use of heat. All of that improves fuel economy and performance, reduces noise and lowers emissions. The new engine eliminates the bulky intake manifold, two heavy cast-iron exhaust manifolds and related parts such as gaskets, bolts, nuts, studs and most heat shields.
The new design could shave $350-600 off the cost of producing the engine by some estimates.
The new compact design also solved a space problem. GM wanted a V* diesel that could fit in the same space as the small block V* gasoline engine in the Chevrolet Silverado-GMC Sierra pickups, and in the Chevrolet Tahoe/GMC Yukon SUVs. Since it is narrower than a regular diesel of the same displacement, the new engine fit.
The engine performance is apparently also impressive. Some GM bigshots (aka decison makers) took it for a test drive on the GM Milford Proving Grounds. They were amazed at how smooth, quiet and powerful the new diesel ran.
The top brass approved the new diesel engine for GM's light-duty trucks. It is scheduled for production in 2009 at a revamped plant in Tonawanda, N.Y.
For all its worth, I'm an engineer (Industrial) but I need to see things visually more or less, so when "gear-heads" start talking (or writing) its somewhat difficult to follow exactly what they are talking about. All in all, sounds like the new Duramax will be evolutionary.