New Honda Engine a No-Go in State : Technology: The ‘lean-burn,’ fuel-efficient model emits too much nitrogen oxide to comply with California pollution regulations.


Honda Motor Co.’s new “lean-burn” engine, touted as a significant advance in fuel efficiency, won’t be offered for sale in California because it spews out too much nitrogen oxide, company officials now say.

In announcing the engine July 30, the Japanese auto maker’s U.S. representatives said it met both U.S. clean-air standards and the more stringent California requirements. But company officials acknowledged this week that they were mistaken.

The same basic engine--without the lean-burn feature--will be offered in the 1992 Civic this fall in California. It will be about 8% less fuel efficient than the version sold in the other 49 states, Honda said.


At 44 miles per gallon in city driving and 51 m.p.g. on the highway--versus 48 m.p.g. and 55 m.p.g. in the rest of the country--the California engine will still represent a big gain in fuel economy for a car of its size.

The 1992 four-seat Civic’s California fuel economy will slightly exceed that of the 1991 Honda CRX-HF, the U.S. Environmental Protection Agency said. But the CRX-HF has just two seats, is a foot shorter, weighs 127 pounds less and manages just 62 horsepower, compared to 92 for the new Civic.

The 1991 five-seat Honda Civic, which is being replaced this fall with a completely new car, is rated at 33 m.p.g. in city driving and 37 m.p.g. on the highway.

The improvement is due to the engine’s variable valve timing. It is expected to be the first mass production of that technology.

The failure of the technology to meet California’s emissions standards--which will become national standards in 1994--underscores what has long been known to be a problem with the lean-burn system.

Lean-burn technology--in which one part fuel is injected into each combustion chamber for every 25 parts of air--means that the engine swallows less gasoline. Today’s conventional car engines burn a 1-to-15 ratio.


But when adjusted to burn an unusually lean mixture of fuel to air--the other half of Honda’s big engine announcement--the power plant emits more than 0.4 grams of nitrogen oxide per mile.

That makes it illegal in California. The lean-burn engine meets the federal standard of 1 gram per mile, but the more stringent California requirement takes effect nationally in 1994.

Among other air quality problems associated with nitrogen oxide, the chemical combines with hydrocarbons to create smog.

The engine to be sold in California is “the same engine, with the variable valve timing. But to meet the (nitrogen oxide) standard, it will not utilize lean-burn technology,” said a Honda spokesman in Torrance.

“Fuel economy will suffer. But horsepower and torque ratings remain the same.”

Bill Sessa, a spokesman for the California Air Resources Board, said Honda didn’t bother asking the board to approve the lean-burn version of the engine for sale in the 1992 model year.