engineerguy.com
YouTube Twitter Facebook
engineerguy.com YouTube Twitter Facebook
engineerguy.com

home

books

videos

audio

speeches

awards

about bill

Electric cars

August 21, 2001

A public radio commentary

I'm often asked "why don't we have electric cars?" The tone of the question usually implies some government-industrial conspiracy, led by the auto makers. I find them, though, blameless: General Motors and Toyota put a half billion dollars into electric cars. And they each brought out one that flopped. The real culprit is much less interesting. It's batteries.

Finding powerful enough batteries is the Achilles' heel of electric cars. You can visualize the problem like this: A typical car carries one hundred pounds of gas, which moves the car about 250 miles. To have the same range, an electric car would need 1000 pounds of batteries - over four times as much. This means the whole car would be filled with batteries. The bad news is that there is no battery breakthrough on the horizon to fix this problem.

So, is the gasoline powered engine always to rule the roadways? Is there no hope of a takeover by electric cars? The good news is electric cars are succeeding, but only after taking a tip from that great political philosopher Machiavelli.

He advised ambitious Princes that "[t]he best and most certain way" to take over a dominion was to "take up residence there." And that's exactly what's happening: Hybrid cars that combine electric and gas powered motors are now appearing on the road.

These hybrids bring out the best of both engines. The weakness of the gas engine is the energy it wastes. Only about a quarter of the energy in the tank is used to move the car forward, most is lost during breaking, and as heat radiating from the car. Keep that in mind the next time you fill your tank: For every ten bucks of gas you put in, your engine tosses away seven dollars and fifty cents.

In a hybrid, though, when the brakes are hit, and energy wasted, the electric motor comes into play. During braking the gas engine uses its surplus energy to charge the batteries. Then when the hybrid car accelerates, the electric motor uses this power to assist the gas engine, allowing that engine to be smaller. This decreases the amount of gas used, so much so that some hybrid cars get 60 miles to the gallon. For most people this would mean one stop a month at the gas station.

Will these new hybrid cars succeed? To do so, they must hit consumers in the pocketbook - and these hybrids don't yet do it. Although current models save fuel and exhaust fewer pollutants than conventional cars, these savings still don't match the price difference between a hybrid and a conventional car. But keep your eyes open as every auto maker brings out a hybrid electric and gas car, and competes for market share.

Copyright 2001 William S. Hammack Enterprises