Safe Speed Forums

Could some one enlighten me about hybrids. Ok you have a normal petrol engine and an electric motor. The petrol engine drives a generator that charges the batteries or drives the motor. On down hills the energy from the drive wheels can be used to charge the batteries. It's all great, gives low emissions and will save the world or something.

But I don't understand. Is the engine any more effecient than the engine in the equivalent Corolla for example, ie grammes of fuel used per KW/hr? It has to as the only scource of power is the petrol engine, if so why bother with the electric motor bit? If the batteries go flat the only way to charge them is by running the engine.

If one drives one of these things in the normal manner, will one see much difference in fuel consumption? I wager it would be no better than my car, because it will still need the same amount of energy that my car does to move along at a given speed.

Am I missing something here?

Well the amount of fuel consumed by a petrol engine is related to the load placed upon it as well as the speed at which it is run.
Driving a generator to charge batteries places less load on the engine than driving the transmission, thus less fuel consumed I presume.
And don't the two engines share the load? A petrol engine aided by batteries is going to consume less fuel than one driving the vehicle on its own.

All the energy originally comes from the petrol, but there is an advantage because less energy is wasted when braking or coasting downhill. Magnets on the wheels turn some of the kinetic energy into electricity instead of dumping it as heat. The electricity can then be used to assist the engine with an electric motor, saving fuel.

Lightly loaded engines are far less efficient because of friction losses within the engine itself. Remember how stiff an engine is to turn over? But with a high output the friction losses remain the same and the efficiency rises considerably.

So the name of the hybrid game is to try to keep the petrol engine running at high loads where it's at its most efficient.

However an awful lot of energy goes into making (fairly) short-life batteries, not to mention the motor, drive arrangements, controls, and finally battery maintenance and disposal.

I wouldn't be surprised to hear that the life time energy budget of a hybrid is worse than a typical small diesel.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

The increase in fuel efficiency is not substantial compared to the complexity and cost. Hybrids have a very short shelf life in the evolution of so called "green" energy. You are better of with a diesel.

here is some infor anyway..http://www.howstuffworks.com/hybrid-car9.htm

I would NEVER consider getting one. The maintanance costs further down the line will be horrendous.

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Speed camera policy Kills

hybrids are definitely (only) a stepping stone to full electric, but full electric needs a power source such as hydrogen based fuel cell which have their own problems.. and in my opinion are at least 15years from series production.

currently available hybrid models are all parallel configuration rather than series as far as i'm aware. there's a good description here:
http://people.bath.ac.uk/en1wros/Electric.htm

Am I missing something regarding fuel consumption figures? I know the US gallon is different but....

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Tailgaters - Please Pass
You have an Accident to go to!

At $2 per US gallon would you be bothered about fuel consumption.

What they don't say in the Hybrid hype is most of the 100,000 or so cars that have been sold to date have been to US and Japanese Government organisations. I assume driven by political correctness rather than market forces.

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Speed camera policy Kills

Just did the conversion to imperial and 37miles per US gallon = 44.43 miles per Imperial Gallon and 29 US = 34 UK.

Ok it's better, but nothing to write home about. The reason the Accord interested me is because I've got one; I would expect not much worse from mine.

Max

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Tailgaters - Please Pass
You have an Accident to go to!

But does it have 255hp?

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Speed camera policy Kills

And the UK forgets "DUALFUEL" CARS such as the ASTRA/VECTRA.


tut , tut , mr brown

Thank goodness!

Bet you won't see John Prescot driving one.

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Speed camera policy Kills

He takes tablets for gas, don't seem to work though

The Americans are fuming about it, their used to $1 a gallon. I say to any disgruntled American 'come to Britain and see how lucky you really are' (if you can bear to stay long enough) And i'm not just talking about your fuel prices....just about everything else as well.


Regards


Andrew

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It's a scam........or possibly a scamola


Homer Simpson

New on the Prius.

Not exactly the most popular car sold in the UK.

it represents 0.13% of car sales here.

http://www.carkeys.co.uk/news/2005/april/07/5877.asp

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Speed camera policy Kills