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I just happened to have a older truck to modify. Any car can be used (although the lighter the better) for a hybrid. I needed a test vehicle capable of demonstrating different versions, both series and parallel, so I settled on a four-wheel drive pickup because there is enough room in the rear for the engine/generator package while the original engine remains up front. The rear wheels are powered by the electric motor; the front by the original gas engine. Vehicles modified at home will probably have the original engine removed, but I needed both to demonstrate efficiency, performance, etc. The truck is modified by removing the rear drive shaft altogether and mounting a short drive shaft and an electric clutch to the motor. The short drive shaft is the same as the front drive shaft in length.

MOTHER:

What kind of performance are you getting?

DA:

The electric motor performs and accelerates best at low speeds, as opposed to a gasoline engine which has most of its torque at the high end. So depending upon maintenance, charging, etc., you accelerate from zero to 40 mph in six to eight seconds. The engine-driven generator can handle the demand from the main motor up to speeds of about 50 mph. The "stored" energy in the batteries comes into play at higher velocities, giving extra kick for passing and climbing hills. Gearing can be changed if higher performance is desired but the truck was never really intended to be a scorcher. I was gunning for reliability and efficiency. Let the speed enthusiasts think up a supercharger if they want one!

MOTHER:

But isn't driving the truck dramatically different from driving a conventional car?

DA:

It's exactly the same. There is a slight hum from the electric motor and a bit of noise from the diesel engine, but actually, noise levels in the cab are lower than those in a conventional car.

MOTHER:

What kind of mileage do you get when the diesel engine is running?

DA:

A 25-mile test run using the nine-hp diesel engine showed that a gallon of fuel could produce sufficient amperage at 36 volts to drive the car two hours at 45 mph. That's 90 miles to the gallon. If the terrain had been a bit less hilly, the average speed would have been closer to 55 mph. It's important to realize, however that stop-and-go traffic shortens the range and reduces efficiency because of the heavy current draws (600 amps) in taking off. That's where the surge current (cranking power) of the battery comes in. A great deal of city driving will certainly affect overall fuel economy.

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