General Motors plans to boost the fuel economy of its larger vehicles as early as 2004 by equipping them with Displacement-on-Demand engines. These engines will boost fuel economy by roughly 8 percent based on EPA testing procedures, and possibly up to 25 percent in real-world conditions. GM plans to produce 150,000 of the engines the first year, expanding production to nearly 1.5 million per year by 2007. The technology will be used in standard and optional Vortec engines in full-size trucks and SUVs. Displacement-on-Demand technology is based on the fact that once a vehicle reaches its cruising speed, it needs only a fraction of the power available from its engine. Therefore, engines using the system will shut down half their cylinders under normal driving conditions, instantly activating the other half whenever power is needed for acceleration or hauling. GM currently leads the industry in truck fuel economy. According to Sam Winegarden, chief engineer for Vortec V8 engines, “Displacement on Demand will allow us to maintain that leadership position well into the future.” He added that, “Because there is no degradation in emissions, this technology will improve overall emissions to the extent that less fuel is consumed.” In 1981, GM offered a primitive version of this system on Cadillac, but the on-board computers and other parts of the technology were not able to cope with the job. For example, today’s engine computer is 25 times faster, has 50 times the computing power and 100 times the memory of the 1981 engine controller. In addition, where the 1981 engine used a mechanical throttle and transmission control, in today’s engines those systems are all electronic. The electronic controls allow precise engine torque control at all times, and provide more accurate information to the transmission for shift-point selection.