Two electric motors, a V-8 engine that can work on only four cylinders, a really smart computer, and a four-speed transmission that joins them into one package. GM calls it “dual hybrid” technology and says that soon it will make pickup trucks or big sport utility vehicles as fuel efficient as some cars.The technology, showcased with General Motors Corp.’s future engines and powertrains Thursday at the company’s proving grounds northwest of Detroit, will start showing up in the 2008 model year with the GMC Tahoe SUV. It will be available on the GMC Yukon and Cadillac Escalade SUVs and the Chevrolet Silverado pickup – GM’s top-selling vehicle – later that year.GM says the hybrids, similar to those now in use in the transit buses of 39 cities, are so versatile that they will boost fuel economy by 25 percent over the current SUVs and pickups. For the two-wheel-drive Tahoe, which now gets an average of 18.3 miles per gallon in combined city-highway driving, that means nearly 23 mpg. News source: Forbres.Com GM says the hybrids, similar to those now in use in the transit buses of 39 cities, are so versatile that they will boost fuel economy by 25 percent over the current SUVs and pickups. For the two-wheel-drive Tahoe, which now gets an average of 18.3 miles per gallon in combined city-highway driving, that means nearly 23 mpg.Figures for city and highway driving haven’t been calculated yet, but Tim Grewe, GM’s chief engineer for rear-wheel-drive powertrain hybrids, said there will be a significant improvement.”We give you the highway economy and we give you the city economy while maintaining SUV performance,” he said.The dual hybrids, developed jointly by thousands of engineers with GM, DaimlerChrysler AG and BMW AG, also will be placed in the Dodge Durango and BMW vehicles.Prices on the GM vehicles haven’t been set, Grewe said, but the company plans to make them competitive, similar to a $2,000 premium on the hybrid version of the Saturn Vue.The powertrains are huge for GM and its partners because they take the gas-guzzling prefix off of trucks and bring people back into the market, said Jim Sanfilippo, senior industry analyst for Bloomfield Hills-based Automotive Marketing Consultants Inc.”It’s a big thing. It’s a terrific thing,” Sanfilippo said.Most current hybrids are efficient in stop-and-start city driving, Grewe said, but they aren’t as efficient at highway speeds.The new technology, Grewe said, uses a computer to chose from thousands of combinations of running on one electric motor, two electric motors, a combination of electric motors and the V-8 Fuel engine, or shutting down some of the V-8’s cylinders.The computer judges speed, the load the vehicle is pulling, terrain, temperature and humidity, whether the pavement is wet and other factors to decide the most fuel-efficient combination of technologies, Grewe said.”It’s got a gazillion choices to make, and it makes them 100 times a second,” Grewe said. “It’s like having the world’s smartest co-pilot.”And although the technology is complex, it has been proved in buses, some of which have 150,000 miles on them and have been used since 2002, Grewe said.As automakers continue developing hydrogen fuel cells, Grewe said the future of fuel-efficient engines will include a combination of smaller diesels, Fuel engines and hybrids. GM has teams of engineers working to make all the technologies more fuel efficient and environmentally friendly, engineers said Thursday.Sanfilippo said the new hybrids should take away the environmental stigma attached to driving a pickup or big SUV.”It certainly is going to reopen the door to people who don’t necessarily work with their pickups but like to drive one. It makes them politically correct.”