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GM's "Displacement on Demand" engines

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Displacement on Demand Arrives in 2005 GM SUVs

Motor - July 3, 2003

Motor Trend

General Motors has announced that the 2005 GMC Envoy XL, Envoy XUV and Chevrolet TrailBlazer EXT will be the first vehicles to showcase its innovative Displacement on Demand (DOD) fuel-saving technology. DOD will be a standard feature in these vehicles' optional Vortec 5300 V-8 engine. The more efficient engine will boost the fuel economy of these vehicles by about 8%.

GM previously announced it will also introduce this technology as part of a new overhead-valve V-6 family of engines in some 2006 midsize passenger cars. By 2008, the General expects that more than two million vehicles with the V-8 and V-6 engines will feature DOD.


"Displacement on Demand will enhance fuel economy without compromising performance or the ability to carry heavy loads," said Sam Winegarden, GM Powertrain chief engineer of Vortec V-8 engines. "We will be able to deliver the same top-of-the-line performance with less effort and energy. That's the essence of efficiency."

DOD saves fuel by using only half of the engines cylinders during most normal driving conditions. When loads are light, the control system automatically closes both intake and exhaust valves for half of the cylinders, cutting off their air and fuel supply. The valves are reopened to provide all-cylinder operation when the driver needs it for quick acceleration or for hauling heavy loads.

The V-8 engine always starts on eight cylinders, and in the case of the V6 engine, six cylinders. But once the vehicle has accelerated to speed, the engine control module activates Displacement on Demand, providing improved fuel economy through a relatively inexpensive change in displacement to meet vehicle load requirements.

© 2003 Motor.

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Guest saleen351

well 8% is good, but not great...

but didn't caddy do this already years ago? i think where if the car was overheating the car would shut off half the cylinders too keep the heat down???

anyways, its a simple great idea, and just another example that in the near future we can tell the saudis to go fuck themselves..

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