Posted on 08/23/2003 6:06:27 PM PDT by eldoradude
Had one of those out back when I was a kid; the crescent-shaped window in the door was sorta neat... '-}
Electricty is generally a little easier to handle and distribute with the existing power grid. Overall there is less waste.
It is true that the efficiency of an overall system is the product of all the subsystem efficiencies. For example in a car that burns gasoline we have the engine efficiency, drive train efficiency, chasis efficiency, etc. all subassemblies with their own efficiencies. Multiply all these together and you get the overall efficieny of the car. The 90 to 95 % I cited relates primarily to the engines -so the overall will be a little less when you factor in drive trains, etc. But I purposely neglected distribution to get a better comparison of the vehicles themselves.
True. A basic engineering rule is - it has to be not only technologically but economically feasible otherwise its no good. Electric cars are neither right now - and maybe never. We could probably technologically design a 100 story building that could sustain a fully fueled 757 collision - but it wouldn't be economically feasible.
In general, a vehicle that uses all natural gas is much more efficient and produces less emissions than a gasoline powered car. In fact there are many all natural gas vehicles on the road now. There is a natural gas refueling station down the road from my house.
Natural gas is already in a gaseous state when its injected into the engine and ignited. Gasoline has to be vaporized to some extent when its injected into your engine and ignited. When you start your car up in the morning, you have what's known as a cold start. This is a key point in time when substantial emissions are produced by your car. Natural gas eliminates cold starts and emissions. It also burns hotter and more completely than gasoline.
The primary problem with an all electric vehicle is that battery technology isn't there to make it feasible. An electric motor is more efficient than a gas burning motor. If the technology was there for all electric vehicles it would be more efficient and produce less overall emissions to burn the gas in a power plant and produce electricity to charge batteries because power plants are more efficient than millions of small engines. Electric vehicles are ideal but not now currently realistic.
So how can we realistically (technologically and economically - from an engineering standpoint) improve the efficiency and therefore energy use of millions of smaller cars. We use a hybrid vehicle which incorporates a hydrocarbon fuel (like gasoline or natural gas) engine and a small electric engine combined. Remember the goal is to improve the efficiency of millions of smaller vehicles. The hybrid car that I designed used natural gas and only a very very small battery pack (and by the way the same type of batteries in your car now - lead acid). So the amount of energy and time needed to recharge the batteries is low. Regenerative braking aids in recharging.
You do need some electrical energy produced from a power plant or other source. But the quantity compared to what would be required for an all electric vehicle is substantially less because your only dealing with a fraction of the batteries. Quiet possibly in the near future a couple of solar panels might be all you need. So with a hybrid car you have substantially improved efficiency and fuel use in millions of small cars with a minimal increase in electrical demand.
For comparison purposes only (I'm not a tree hugger, I'm an engineer): Gasoline engines in cars are extremely inefficient - 20% or less. Electric engines are very efficient 90%+. So if we could replace millions of inefficient engines with efficient engines we would overall get more bang for your buck (energy useage) with an electric motor than a gas motor.
With respect to power plants: they are more efficient in burning hydrocarbon fuels 35 to 40% than an individual car. So comparitively you have maybe hundreds of higher efficiency power plants as opposed to millions of lower efficiency car engines. Not only that, power plants can also use water, wind, nuclear and solar sources to produce electricity.
Nothing wrong with making engineering improvements over what we have. If everyone thought otherwise we'd still be driving wagons with horses pulling them or model T's or ...Hey if you could buy an electric car that gave you all the price and performance of the car you own today it would be nice - but the technology isn't there and may never be there.
The Long Ranger range-extending trailer converts an electric vehicle to hybrid mode for long trips. The efficient, high specific-output, gasoline-fueled, trailer-mounted generator maintains battery charge, allowing unlimited driving range at speeds up to 75 mph.The Long Ranger is proven over more than 20,000 highway miles. 20-kW DC output allows sustained high-speed driving without range restrictions. Emissions are controlled with a closed loop fuel control system and a zero-evaporative-emissions sealed fuel tank.
The intelligent BackTracker trailer steering maintains trailer-to-vehicle alignment during backing to avoid jack-knifing. Steering control algorithms enhance high-speed stability allowing reduced trailer and tongue length. Small, light, and short for easy towing, parking, hookup, and storage. Manual start/stop control is available from inside the vehicle The backtracker system keeps the trailer in line with the vehicle while turning - even going backwards!
Low-Emission Range Extender for Electric Vehicles - paper presented at the SAE Future Transportation Conference in 1997 summarizing the technology in AC Propulsion's Backtracker hybrid Trailer.
Specifications:
Output Power - 20 kW DC up to 7000 ft elevation
Output Voltage 240 - 390 volts
Maximum Output Current 60 amps
Dimensions length: 48",(from hitch), width: 48", height: 30"
Fuel high-octane unleaded gasoline
Fuel Capacity 9.5 gallons (40 liters)
Engine Kawasaki 500cc 2 cyl. DOHC 4-valve/cyl, liquid-cooled
Operating Speed 7000 rpm
Drive direct Alternator proprietary design
Controls electronic servo governor, remote start and stop
Maximum Speed (without battery discharge) 60 - 80 mph varies with vehicle)
Highway Fuel Economy 30 - 35 mpg, 7.8 - 6.7 l/100 km(varies with vehicle)
Total Trailer Weight 350 lb, 160 kg
Trailer Chassis chrome-moly tubular frame with torsion-arm suspension
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