Ford Motor Co. has abandoned plans to use "mild hybrid" technology on future versions of the Explorer, an effort that it had touted to dramatically improve fuel efficiency for the world's best-selling sport utility vehicle, the Detroit Free Press has reported on its auto.com Web site. Citing Ford engineers and company insiders, auto.com said that Ford, blaming a cash crunch and less success with the gasoline-electric hybrid than expected, has decided to limit hybrid systems to smaller trucks and cars because it boosts fuel efficiency more in smaller vehicles. Like Honda's Insight hybrid, Ford's mild hybrid uses an integrated starter generator. The gasoline engine shuts off when the vehicle stops. Upon acceleration, the gasoline engine restarts instantly and gives the vehicle a boost to take off. The Explorer hybrid was a key component of Ford's much-touted plan to boost SUV fuel efficiency 25 percent by 2005, a vow then-CEO Jacques Nasser made last July in a Washington Press Club speech. Auto.com said a Ford spokeswoman would not discuss the fate of a mild hybrid Explorer but said the company still stands by the 25 percent improvement goal. Ford's environmental goals have taken on greater prominence in recent years because new chairman and CEO William Clay Ford Jr. has been an advocate of making automakers more environmentally sensitive. The Web site said that Ford on Nov. 14 told business leaders in Kansas City, Mo., that the automaker is still committed to a hybrid version of its small SUV, the Escape, in 2003, plus a Focus equipped with a fuel cell in 2004. However, auto.com quoted Ford insiders as saying that the hybrid was dropped for the Explorer because it just wasn't making economic sense. “If something like the hybrid doesn't give the kind of returns it was supposed to, it would just have been financially irresponsible to pursue it on the Explorer,” the anonymous Ford official told auto.com. “It makes more sense on smaller vehicles.” Auto.com said Ford was getting fuel-efficiency gains of only 5 to 10 percent on tests of the Explorer equipped with the mild hybrid. A conventional Explorer gets about 20 miles per gallon, and the goal was to improve that to 25 mpg or better. Ford spokeswoman Sarah Tatchio told auto.com that the integrated starter generator still has a future. “We are still absolutely pursuing use of the integrated starter generator on our products, and we are going to deliver on our goal of a 25 percent improvement in the fuel economy of our SUV line by 2005,” Tatchio said. She told auto.com that Ford would improve sport-utility fuel efficiency in other ways, such as making the vehicles lighter.