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Thursday, April 16, 1998

Automakers take another look at diesel engines

BY SAYURI DAIMON

Staff writer

Last December, Toyota Motor Corp. impressed the auto industry by introducing the 2.15 million yen Prius, the first passenger car powered by an electric motor and a gasoline engine. But some automakers now complain that Prius' low price has killed the potential market for hybrid cars.

"No automaker will be able to compete with Toyota's price. If no one follows Toyota in introducing new hybrid cars, the market for them will not grow," said a managing director of a major Japanese automaker.

Instead of working toward a completely new type of environmentally friendly car like the Prius, many carmakers now seem to believe that existing gasoline and diesel engines can be made more efficient. "Developing a totally new car would require a lot of time and money. We believe that improving existing engines is a much more effective means of protecting the environment," said Satoru Toyama, managing director of Mitsubishi Motors Corp.

Industry experts say that more car manufacturers are focusing on creating efficient diesel engines because their excellent fuel economy can contribute greatly to the reduction of carbon dioxide emissions. For example, a new Nissan Motor Co. minivan almost make a driver forget that the vehicle is powered by a small direct fuel injection diesel engine because it runs so smoothly, with less noise and vibration than conventional diesel engines, company officials said.

According to Nissan, its NEO Di diesel engine, which will make its debut on the Japanese market early this summer, will also reduce nitrogen oxide and carbon dioxide by 30 percent over conventional diesel engines. The automaker will create new 3-liter and 2.5-liter diesel engines.

Direct-injection diesel engines have actually been on the market for a long time, but because of their effective fuel economy, they have usually been used for large vehicles such as trucks and buses. The vehicles' noise and black smoke emissions prevented automakers from adopting direct-injection diesel engines for smaller passenger cars.

To solve such problems, Nissan has adopted a new system that ensures a high-pressure injection and has improved atomization to effectively mix air and fuel, thereby reducing black smoke. Recycling exhaust gas back into the cylinders will help reduce combustion temperature, which will also result in fewer nitrogen oxide emissions.

The firm also developed an electronically controlled fluid-filled engine mount to cancel out vibrations that ordinarily are transmitted from the engine to the body of a vehicle. "Many people have long regarded it impossible to remove noise, black smoke and vibration from a diesel engine, but automakers have begun to notice that they can solve these problems with their technology," said Soichiro Yoshida, president of Nagano-based Yoshida & Co.

Yoshida's firm, hoping that diesel engines will be widely accepted in the future, opened a plant in Nagano last year to produce diesel oil from Kentucky Fried Chicken restaurants' used cooking oil. Yoshida's firm has recently begun a test program of his biodiesel fuel using Nissan's new direct-injection diesel engine.

"The fuel economy of a diesel engine is about 30 percent to 40 percent better than that of a gasoline engine of the same size, and if automakers continue to work on their diesel technology, diesel engines will become the major (engines) in Japan, just as they are in Europe," he said.

MMC, which introduced the first direct-injection gasoline engine ahead of its rivals in 1996, is also set to introduce next year 2.5-liter and 3-liter direct-injection diesel engines, which will reduce carbon dioxide emissions by 30 percent and increase power by between 20 percent and 30 percent over ordinary diesel engines.

Industry personnel predict that the diesel engine war among the world's leading automakers is likely to first intensify in Europe, where about 20 percent of the region's passenger cars are powered by diesel engines.

While Mazda Motor Corp. will start exporting its Capella model with a new direct-injection diesel engine this year, MMC also expressed its readiness to ship the new diesel engine to Europe.

In Europe, diesel engine-powered cars are widely accepted because of the inexpensiveness of the light oil they use. In France, where 40 percent of the passenger cars are reportedly powered by diesel engines, light oil costs only half as much as gasoline.

Europeans also seem to place a higher priority on fuel economy because they usually drive long distances, according to industry personnel.

In February, Isuzu Motors Ltd. started to sell in Japan its Bighorn sports-utility vehicle, which included a newly developed 3-liter direct-injection diesel engine using the common rail system. "Japanese automakers' technology is developing very fast and their diesel technology may threaten our business in the future," said Isato Mochida, assistant manager of Mercedes-Benz Japan Co.'s corporate office.

There is a good possibility that such competition will hit the Japanese market in the future as Japan introduces more stringent emissions level controls. According to Japan's new emissions controls, which will take effect in October, nitrogen oxide emissions from diesel engine-powered passenger cars must be lower than 0.55 grams per km as compared with 0.84 grams under current regulations.

Particulate emissions are also to be reduced to 0.14 grams per km from 0.34 grams under the new controls.

In the United States, public awareness of carbon dioxide emissions and the use of diesel engines is believed to be less strong because of inexpensive gasoline prices there, according to those in the industry in Japan.

"Unless U.S. automakers participate in the technology competition that already has begun in Japan and Europe, they will only be able to sell cars in their own country," said Nobuo Ohkubo, managing director of Nissan.



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