Either Way, the Environment Wins

Auto Industry Debates Virtues of Diesels vs. Hybrids

By DANNY HAKIM - Published: August 5, 2004 RAVERSE CITY, Mich., Aug. 4 - Automakers remain divided on whether diesel or hybrid cars are the best way to improve fuel efficiency, and the split is often drawn along cultural lines. All the major manufacturers are developing cleaner diesel engines, hybrids and hydrogen fuel cells. But companies are pushing harder on different technologies to get a leg up in meeting regulations that are becoming tougher around the world, and their views were represented in comments made at a management conference here on Wednesday. Toyota and Honda first developed hybrid-electric vehicles, in part because they save the most gasoline in the sort of stop-and-start driving that is common in the clogged traffic of densely populated Japan. In a hybrid like the Toyota Prius, an electric motor takes over for the gas engine at low speeds and stops; energy is also preserved that is usually lost in braking. But automakers in Europe are skeptical about how profitable hybrids can be and prefer diesel-powered vehicles because they offer car owners an alternative to high taxes on gasoline. Environmental advocates remain cautious about diesels. Compared with conventional gasoline cars, they offer lower emissions of the kind that contribute to global warming but lag behind in emissions of smog-forming pollutants - though filtration technology is improving. New air-quality rules that will be in effect in the United States by the end of the decade will require diesel and gasoline engines to meet the same emission levels....