Civic Vx `Dream Car': Shifty But Not A Sham

SAN DIEGO, Calif. - There it sat: the most fuel-efficient four-cylinder car in America, waiting to carry us forever on a mere whiff of gasoline.

The 1992 Honda Civic VX Hatchback. The oil companies' worst nightmare.

When word of Honda's new Civic VX got out, it sounded like God's gift to everyone - and another embarrassing blow to U.S. automakers.

The Civic VX was rated by the federal Environmental Protection Agency at 55 miles per gallon on the highway and 48 mpg in the city. Such fuel economy would please the hardest-core environmentalists. After all, by the EPA's estimate, we're talking 654 miles of highway cruising per tankful.

In addition, the VX is rated at 92 horsepower, which held out the promise of spirited acceleration due to a relatively lightweight (2,094-pound curbweight) package. That would please driving enthusiasts.

The VX's new variable-valve, lean-burn engine, the VTEC-E, immediately was given the credit.

What happens when great expectations for fuel economy meet reality? Honda recently gave us a chance to find out.

The VX test drive took place near San Diego, and the Cliff Notes summary is that trying to get fuel economy close to that shown in the EPA estimates apparently means one must drive Civic VX very, very carefully.

It means paying extremely close attention to the dash-mounted "upshift" light that tells when you should select a higher gear. Equipping the vehicle with that light allows Honda to use a slightly different certification method with the EPA, which helps boost its fuel-economy rating.

There is little time between shifts, and by the time I hit 40 miles per hour on a straight, the VX had ordered us into fifth gear.

Following the upshift light may result in excellent fuel economy, but it puts the VX into the Winnebago category when it comes to keeping up with traffic while pulling away from a stop light.

I also tried the VX without the upshift light. A moderately steep hill required second gear to make any real progress.

Push down hard on the gas, and the little four-cylinder revs quickly, happily. When pushed, the VTEC-E can produce. The VX scoots ahead eagerly. But we are approaching the red line, and it is time to shift into third gear. I shift. Uh-oh, bad news. Engine speed drops way down, as does vehicle speed. Time to wait patiently for speed to build again.

What has happened is that Honda has chosen widely spaced gear ratios that allow engine speed to drop off considerably when a higher gear is selected, greatly improving fuel economy but at the price of crisp acceleration.

This doesn't mean the Civic VX is a sham. The VTEC-E engine is impressive, but the reality is the EPA ratings of 48 city and 55 highway resulted from a fuel economy package, not from some magical, mystical engine breakthrough from Honda.

The idea behind the VTEC-E is that it mixes more air with gasoline than in a normal engine. Then, the VTEC-E uses a special design to burn the mixture efficiently.

The result is better fuel economy, but it produces more than its fair share of the air pollutant known as oxides of nitrogen.

In fact, the VTEC-E doesn't meet California's stringent air-pollution standards for oxides of nitrogen. For the time being, however, it meets air pollution standards in the other 49 states.

SYSTEM RAISES FUEL EFFICIENCY

Both the Honda and the Mitsubishi technological advances in fuel efficiency announced Tuesday in Tokyo utilizes a system that allows a greater ratio of air to fuel to be injected into and ignited in a car's cylinder.

STANDARD ENGINE In a conventional Mitsubishi three-cylinder engine (1), air and fuel are injected into the cylinder via "siamese" or double injectors and ignited by a spark plug. Because of the more efficient blending of air and fuel (3), a higher ratio of air to fuel can be used.

MVV (Mitsubishi Vertical Vortex) In the new Mitsubishi system, the mixture of fuel and air is injected into the cylinder in a "vortex" or swirling pattern of layers of fuel and air (2). Ignition of the air-fuel mixture in the MVV system (4) creates the same amount of power with less fuel, resulting in greater fuel economy.

SOURCE: DETROIT FREE PRESS, MITSUBISHI MOTOR CORPORATION.