Mother's Own Hybrid Car!

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If there's one thing we've learned from working with the hybrid car, it's that reduced weight is a key factor in achieving increased fuel economy. Our goal, then, was to build a machine which weighed no more than 900 pounds ... and we ended up doing even better than we'd hoped!

Motive power for our lightweight creation comes from a one-cyciinder, 6.4 (DIN continuous rating) horsepower Lombardini diesel engine, driven through a set of Salisbury clutches that allow for an infinitely variable gear ratio, governed by load. Final drive is at a fuel-saving 2.82-to-1 ratio, using a chain and sprocket system connected to the axle of the right rear wheel.

MOTHER's roadster, in its present configuration, weighs in at just about 675 pounds . . . a figure we never imagined—several months ago—we'd be able to achieve. However, surprised as we were at the lightness of the machine, the real shock was the car's mileage: At this point, with the engine still as yet not broken in, we're getting as high as 129 miles per gallon in actual suburban driving . . . and we hope to improve that figure—and the vehicle's approximately 45-MPH top speed—as time goes on.

Right now, though, we're working on body design, and—although the increased weight of a "shell" will add a few unwanted pounds—its wind-cutting configuration (not to mention the convenience and comfort it will provide to the driver and passenger) should completely offset any such disadvantages. We'll keep you posted on the developments of this project as they occur . . . in'the meantime, maybe we'll do some economy testing using vegetable oil as fuel!

THE PROOF IS IN THE TESTING

Once our Subaru was set up as described . . . and we had installed our final engine choice, which was still "tight" with only three hours on it ( the break-in time is from 30 to 50 hours), we achieved more than satisfying "mountain driving" results. With a fully charged battery pack and carrying 300 pounds of driver and passenger (anal running with open windows, stock tires, and various other "handicaps" not usually associated with high-mileage tests), the fuel economy over the course of our 78-mile test run (with help from the battery pack) worked out to 83.6 miles per gallon. of diesel fuel. The car's top cruising speed on level ground—in its 30-volt configuration—proved to be about 45 MPH . . . although we did hit 55 MPH on a slight downhill stretch.

With the driver controlling the speed of the diesel generator engine, and trying to keep current draws below 200 amps whenever possible by shifting gears (and using the accelerator to vary field voltage) when necessary, the diesel engine—doing its "hybrid job"—more than doubled the range that would have been possible with the batteries alone! (And, of course, when the two separate "fuel systems" worked together, we achieved our best economy figures.)

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