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More Effecient Hybrid

Hybrid without a transmission
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Traditional hybrid electrics are basically a normal car with an electric engine added on before the transmission. I say take out the transmission.. leave a small engine, one that would be just large enough to produce electricity to recharge the cars onboard batteries. You only need a few horsepower to do this. Then use the electricity to power motors that are built into the wheels. The hub of the wheel would be copper wire and the inside rim of the wheel would have magnets on it, so the wheel would turn around the hub. This way you would be more efficient because the energy would be transferred directly into spinning the wheels of the car and none would be wasted in a transmission with lots of moving parts.
mlingley, Aug 01 2005

Electric Porsche 944 http://www.jstraube...usher/EVpusher2.htm
An electric car enthusiast converted a Porsche 944 to electric. When extra range is required, he hooks up a trailer with a gasoline generator. [JephSullivan, Aug 01 2005]

(??) In Wheel Engine http://www.e-tracti...mpany/thewheel.html
I found this link after I posted my idea. Guess it's already been done. [mlingley, Aug 03 2005]


       Well you would need a motor for each wheel and some crazy circuitry to do the differential steering thing.   

       Also instead of inefficiency of one motor and transmission you would have the inefficiency of two motors together, which may well be greater.
pooduck, Aug 01 2005

       A large motor can typically be made more efficient than several smaller motors with the same total power, but as you stated, a transmission is not 100% efficient. In stationary or slow-moving applications, the reduced efficiency of in-wheel motors is countered by the elimination of a somewhat wasteful transmission.   

       However, in fast-moving applications, additional unsprung mass is a bad thing. By putting the motors at the wheels instead of in the suspended chassis, you're introducing engineering problems that introduce additional inefficiencies.   

       Even assuming that it can be done more efficiently than a single-motor-plus-transmission approach, there is the matter of maintenance costs.   

       While this is a good idea, and it has been tried before, current technology is not yet ready for mainstream application. This may change in the future, but for now, I'd say that this is, while not yet properly baked, sitting on the counter waiting for the oven to pre-heat.
Freefall, Aug 01 2005

       What you are proposing as known as a series hybrid. Today's commercially available hybrid cars are parallel hybrids, the gas and electric motors power the wheels together.   

       The beauty of the series hybrid is that you only need to account for the average power the car will require. For normal cars, the designer chooses an engine based on the peak horsepower required. When you are driving down the highway at 55 mph, a normal car might be using around 5 horsepower. You only need your big 200 horsepower engine for things like accelerating quickly and climbing hills. If you combine highway cruising, hill climbing, quick acceleration, etc., your average horsepower is going to be considerably less than 200. A coworker of mine who is an electric car enthusiast has calculated that most cars probably use an average power of less than 10 hp.   

       A series hybrid can use an efficient 10 hp gasoline powered generator to keep the batteries charged. The electric motor can provide more horsepower for quick acceleration and hill climbing when needed, but the little 10 hp gasoline engine can always run at it's most efficient rpm and it's a lot lighter than a big 200 hp engine (or even the 90-or-so hp engines in today's parallel hybrids).   

       See the Electric Porsche 944 link for an example of a series hybrid setup.
JephSullivan, Aug 01 2005

       I'm not sure why I'm not giving this a fishbone for spelling errors, poor writing and lack of research. Maybe it's because there actually is an idea in there.
baconbrain, Aug 02 2005

       Fully baked: Mother Earth News ran a report on this in the eighties, done by a guy in his backyard on an Opel GT. Lots of others have done it since. Haven't we seen a lot on this very subject in this venue already?
elhigh, Aug 02 2005

       Toyota does not change gears, or use a CVT. It varies speeds of various planetary gear parts using MGs (motor-generators). Works well, very simple, no need for a starter. Too complicated to describe here, and most of the internet sites screw it up. Even the factory site gives no clues.   

       On the idea of wheel motors, a company in Rockville, Maryland was making some very nice progress in that area.
moPuddin, Aug 04 2005


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