At the General Motors Powertrain Technology show, ABG learned more about the upcoming 2009 Duramax 4500 diesel V-8. GM made some unusual design choices in order to improve the efficiency and get the engine to fit in the same package size as the traditional small block V-8.
GM started off by choosing a 72 degree bank angle rather than the typical ninety degrees making the engine narrower. Most V-8 engines traditionally have had the intake manifold in the V between the cylinder banks with the exhaust manifolds on the outside of the heads. The new Duramax places the exhaust manifold in the valley along with the turbocharger.
Continue reading about the new Duramax 4500 after the jump.
Placing the exhaust and turbo in the V allows for very short exhaust runs and minimal heat lost from the exhaust gases. That means more of the energy in the hot exhaust can be used to spin the turbo and the response is quick. The intakes are on top of the cylinder heads directly over the intake valves. The outer sides of the cylinder heads are devoid any appendages which allows for easy assembly line installation.
Downstream of the turbocharger comes all the hardware to make the new engine fifty-state legal and Tier 2 Bin 5-compliant. A diesel particulate filter cleans up the soot while excess nitrogen oxides are addressed by a urea injection system. The urea will need to be replenished periodically, but it should last longer than the oil change interval.
Overall, the Duramax 4500 should provide a great, fuel-efficient option for the light duty trucks while improving towing capability. The possibility of installing the new engine in passenger car applications certainly exists thanks to the packaging, but whether it happens will depend in part on how well other new diesels are accepted in the market in the next couple of years.