UPDATE - GM to announce fuel-efficient V8 truck engines
Date: 22-May-01
Country: USA
Author: Michael Ellis
The new engines, part of GM's efforts to maintain its edge in truck fuel-efficiency over rival Ford Motor Co. , resurrect "displacement-on-demand" technology, which automatically shuts off half of the V8's cylinders, temporarily turning it into a more efficient four-cylinder, when the trucks are cruising at a constant speed or carrying a light load. During acceleration or when pulling a heavy load, all eight cylinders do the work.
GM plans to manufacture more than 150,000 of the V8 engines in 2004, and increase production to nearly 1.5 million units annually by 2007.
GM's light truck fleet, weighted by sales, averaged about 21 miles per gallon last year. The new engines would be put in its larger vehicles, which are less fuel efficient, such as the Chevrolet Suburbun full-size SUV, which gets between 14 and 18 miles per gallon.
Sam Winegarden, GM's chief engineer of Vortec V8 engines, said the split-second transition from V8 to a four-cylinder is unnoticeable and vastly superior to when GM's Cadillac division briefly tried a displacement-on-demand engine in 1981.
That engine, which shifted between a V8, a six-cylinder and a four-cylinder, depending on the driving conditions, lasted only about one model year because it shook uncontrollably and the technology was much more costly.
"The capability of the computer in the early 1980s wasn't sophisticated enough," Winegarden said in an interview with Reuters. "Back when Cadillac tried it before, the transition wasn't always seamless. The fuel economy gains were pretty substantial however."
GM officials have been annoyed by Ford's efforts to portray itself as an environmental leader, and have taken more steps to point out their own contributions to raising fuel efficiency and cutting vehicle emissions and pollution.
"We clearly have got the lead there, and we intend to keep that," Winegarden said.
Meanwhile, pressure is mounting on the U.S. government from environmental groups to raise the required fuel efficiency to the same level as cars. President Bush's energy plan, announced last week, said the government will reexamine federal fuel economy standards, with an eye toward raising them "without negatively impacting the U.S. automotive industry."
Winegarden said the new technology costs a minimal amount, and the engines will be standard on many pickup trucks and sport utility vehicles.
The V8 engines will boost fuel economy by up to 25 percent in certain driving conditions. However, the listed fuel economy will rise by about 8 percent, based on the testing procedures required by the U.S. Environmental Protection Agency, which simulates rush hour traffic.
Jim Hall, vice president of industry analysis with consulting firm AutoPacific, said GM could eventually put the new V8 engines in its upcoming Cadillac roadster, to arrive on the market in early 2003, or its Chevrolet Corvette.
"GM is spending money on engines, something they haven't done for a long time," he said. "They realize customers will pay for it."
GM said it is also considering applying displacement-on-demand technology on some of its six-and four-cylinder engines.
Currently, DaimlerChrysler AG's Mercedes is the only major automaker to offer displacement-on-demand engines, making it available on V12 engines for its high-end S600 and CL600 sedan and coupe, which each cost more than $110,000. The engines automatically deactivate half the cylinders, effectively making it into a six-cylinder, when full power is not required. Mercedes also sells a luxury sedan in Germany that has the technology on a V8.
Ford, which said last July that it is aiming to boost the fuel efficiency of its SUVs by 25 percent by 2005, is also considering similar technology for its truck engines, said spokesman Said Deep. The technology could be applied on V8 or the larger V10 engines, he added.
Winegarden said GM is also working on other technology, including variable-valve timing, variable compression, a
