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Hybrid cars
This may be an old subject that has been hashed before and I just missed it. Anyhow I got to thinking about how a hybrid can be a lot mere efficent than a regular car of the same size, weight and aerodynamic shape. Our only source of energy on the earth is the sun other than possibly nuclear, I don't know what created that. If I understand a hybrid correctly it's only form of energy recovery is from small alternators in the wheel hubs that recover the kinetic energy of the mass of the car while braking, but did'nt energy have to be put into the mass of the car to get it moving in the first place? I also understand that the small gasoline engine shuts off at a stoplight, but isn't almost as much energy consumed by the starter of that engine to restart it? Surely nobody wants a small nuclear reactor in their car, so where does the energy come form to make the hybrid more effecient? Don't get me wrong, we do need to conserve the energy we have stored in the form of oil, we're using it up like a drunken salor. Ethanol is helping out as a renewable source and wind is being used, but they are only making a dent in our growing consumption rate, but at least we've started doing something to strech the oil. I don't want to start any shouting matches over this, I'm just curious about how the hybrid can be much more efficent than what we allready have. Frank.
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Hybrid cars
A complicated subject and no expertise here. I'm not even certain how particular hybrids work. A general answer is that conventional engine efficiencies aren't very high due to heat, reciprocating motion and parasitic losses. Reduce those losses and it'll take less energy of all types to operate. Conventional braking also looses much of the energy it takes to start a vehicle in motion through heat loss.
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Hybrid cars
I was under the impression that the hybrid vehicles are gas/diesel over electric, like a train locomotive. This allows the fueled engine to operate on it's most efficient fuel to power to emmissions RPM setting, only when needed. IE the fueled engine is not directly linked to the driving wheels. There are batteries or capacitors which recover the braking energy and stored energy from the running generator for the electric "traction" motor(s) during acceleration. This battery power can suppliment the gernerator power for higher performance or be used alone for quiet/zero emmision operation on some proposed vehicles.
I have also heard that Oshkosh Truck is working on some sort of gas turbine (jet engine) over electric power for an upcomming military application. Dodge is making noises of a diesel-electric hybrid truck in the near future.
There was also talk of a hydraulic accumulator braking system used to recover braking energy. This stored hydraulic pressure was used for additonal power for acceleration. (Ford trucks I think?)
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Let's not over look the fact that Congress and oil company lobbist are quietly "tippy toeing" around mobilizing our country's MASSIVE agricultural resources to put farmer back to work and profitability by gearing our economy to run as much as is possible to run off of SME or RME aka soy methyl ester/rapeseed methyl ester aka "Bio Diesel". Our government and the Dept. of Agriculter pay farmers and land owners BILLIONS of dollars to let their land set idle. Our country could readily cut its oil imports by at least 50% if we put our lands into FULL production of soy beans and rape seed (rape seed makes the best Biodiesel). This would not only make our country MUCH more energy independent but also keep TRILLIONS of energy dollar here in the US and in our economy. Combining electic hybrid technology would be a substantial resource multiplier. In my opinion the biggest reason our county has not already developed the Biodiesel/Renewable energy infrastructure is that the Oil Companies do not want to see companys like Archer Daniels Midland cut into their profits and sales territory.
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I believe most of the efficiency gain in hybrids is due to less energy lost to waste heat, smaller engines that operate almost exclusively in their optimum efficiency bands, and recovery of some energy through brake regeneration. That, and the fact that most hybrids to date are pretty dinky cars. I personally think hybrid technology is a dead end street due to large amounts of hazardous waste (batteries), needless complexity, risk of electrocution in accidents, etc. At one point this technology was heavily subsidized and the automakers sold every one at a loss, but I'm not sure what the economics are these days. IMHO, small diesels will be the wave of the future due to better economics and renewable bio-diesel fuels.
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Amen.
Let's not forget that most diesel engines will run (quite nicely) on just strait vegetable oil. The refining process to generate Bio-Diesel requires quite a bit of energy (heat) and the addition of a refined methanol to create.
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I'm also having a problem with the concept of a hybrid. It seems to violate some of Newton's laws. What we don't realize is that engineers have been working on this for some time and have used all the tricks to cut power losses and power consumption to near optimum levels.
I think we all realize that a gasoline engine's efficiency has improved over the years and that we are or have been at peak efficiency for the last few years. Smog controlling devices decrease this slightly. Every time you change the form of energy you have some sort of loss. I've been told that a gasoline engine is most efficient when driving down the highway at 55-65mph. So using a gasoline engine to charge a battery that in turn operates an electric motor doesn't make sense until you understand that the gasoline engine is tiny. It runs at this optimum speed nearly all of the time when it is running. Braking energy normally turns into heat and is wasted, so having each wheel operator as an alternator/generator makes sense. I understand that the battery lasts about 100,000 miles worth of recharging and is at least $3,000.00 to replace.
The other part that I can't understand is all of these gizmos only costs about $5,000.00 more. I am also told that some sort of Federal Tax credit can be gotten by purchasing one of these energy saving automobiles.
The other part that makes me concerned is 3 years down the road, is the concept or technology obsolete so the normal vehicle having a $15,000.00 trade in value is now worth about $2,000.00. Remember, when you buy it, it is yours!
I'm definitely going to consider the Ford Escape hybrid for my next vehicle purchase which is several years away.
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Hybrids make good around town cars. The inefficiency of the gas is highest when they accelerate from stop, and this is where the high torque electric takes over. I don't believe they are much if any more efficient on the road at speed.
Dave
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They're not new, in the 30's, 40's and early 50's most urban delivery vehicles in Northern Ireland were battery-powered electric vehicles.
There are several variations on the hybrids of today though. The Toyota & Honda version, where the small gas engine powers an electrical system, just like in a train engine, seems the most promising. Although there is a big push to develop the 'parallel' system, wherein a vehicle has a small gas engine, just enough to keep it rolling, then gets a boost from an electric motor that also drives the same transmission as the gas motor does, when it needs to pull away or for more accelleration in general.
One of the most promising however will likely be the Hydrogen assist system. This is basically an electrical device which reduces water into Hydrogen & Oxygen and then injects them into a conventional gas or diesel engine for better performance on less fossil fuel.
The big advantage to this is it can be used on existing vehicles and technology.
Best of luck.
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Murf, in the Honda (and I think the Toyota) the system is not like a locomotive. The electric motor is in line with the drive train just aft of the gas motor and in front of the transmission. It's large diameter and only about as thick as a clutch & pressure plate. The electric motor is only an assist for power. It also bleeds off momentum by helping to recharge the batteries on deceleration.
I would like to see a locomotive type system. I think it would have higher efficiency than this one.
Dave
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