|MadSci Network: Engineering|
The 'electronic car' is a vague term, which could mean anything from a computer controlled standard internal combustion engine to a hybrid IC/ electric motor car, to a full battery/electric to a solar powered test vehicle. Use of electronics to control the engine of a standard car has made possible lower exhaust emissions levels and better fuel economy. In this case it is a win. Solar powered cars are presently impractical in my view, and suitable only for contest test vehicles. Perhaps some solar panels could be added to other electric designs as an additional power source, but it is not at this time worth major development. The full-battery, electric-motor-only car I have reservations about. It certainly pollutes less at the tailpipe, but the overall gain is not so certain. Battery manufacture and recycling (they don't last forever) take back some of the advantage gained and involve a fair amount of lead processing (At least the way things are today, lead-acid is the only viable battery. This could change.). Also, the power plant that made the electricity does create emissions. Large power plants are more efficient than internal combustion engines, and the emissions are probably better controlled at a major power plant, where (for instance) it is possible to install electrostatic precipitators against particulate emissions. The transmission losses of the electricity from plant to auto-charging station are a dead loss, although they may not be that large (5%? I'm guessing...better have a power engineer deal with that aspect of it). However, my main reservation about full-battery electric-only cars is that I don't think the public will accept their limited range and capabilities. This will mean that most of the design and development resources put into these vehicles is likely to be wasted. Hybrid cars, with a small IC engine running at peak efficiency only to run an alternator or recharge a (much smaller) battery pack and with wheels driven by electric motor, seems to me to be the best current engineering solution. From what I have read they are almost as low in total emissions as full-battery (when the power plant emissions are figured in), avoid the weight problems and lead processing problems of full-battery systems, and have far fewer limitations as to range. Moreover, they don't require the creation of a system of recharging stations; present gas stations can continue to be used. This avoids obsolescene of a huge infrastructure in our society. I might add that to really gain the benefit of electric motors, the vehicle should be set up so that during braking, mechanical motion of the car is reconverted back into power in the battery or stored into a spinning flywheel. This applies to either full-battery or hybrid types. Hybrid electric cars strike me as a viable development objective and one that is likely to produce a useable product that will be superior to the standard IC engine car in emissions and fuel economy, and still deliver performance adequate to the buying public. Scientific American magazine recently published a long article on electric cars; you should read that for further information and references. I can not find (Arrrgh!) my copy of that issue, unfortunately, so I can't give you the month.
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