The innovative engine works by reversing the flow of air and exhaust gases going in and out of the cylinder heads. This means that hot exhaust gasses can be transferred to a turbocharger in the gap between the cylinder banks. According to Automotive News, the result is the elimination of numerous parts and more efficient use of heat. This in turn leads to better fuel economy and performance as well as improved NVH and emissions levels.
Some of the parts the design eliminates include the intake manifold, heavy cast-iron exhaust manifolds and their associated parts such as gaskets, bolts, nuts, studs and most heat shields. The design has already been tested in several race cars but is yet to be applied to regular production vehicles.
The first of these new engines is scheduled to enter production in 2009. Before it arrives, GM will release a new 4.5L V8 Duramax turbodiesel, which develops 310hp (231kW) and 705Nm (520lb-ft) of torque and will be sold in all 50 U.S. states.