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[Marks DTM Calib]

Ok, so we keep hearing how the Prius is going to save the planet and all that nonsense!

But, what is it that makes the Prius more efficient.....your thoughts please before I put you all out of your misery!

[Jimbob]

erm, it isnt?

[Marks DTM Calib]

erm, it isnt?

Well actually its mpg is not bad at all.....

[Welung666]

£35 a year road tax too Still wouldn't buy one tho, can't stand small cars  

[Martin_1962]

Thirstier than a similar sized Diesel car, massive pollution problems from the battery manufacture, disposal problems of same batteries.

[Jay w]

i can't see it myself.....

the car has a potential disposal issue, batteries generally have a slightly acidic nature to them for starters.

the whole build and shipping worries me as well.......so lets build a car that has lots of/one huge great big battery, then shove it on a container ship and shove it half way round the world, thus causing more pollution.....but this is a eco friendly car so that makes it all OK (NOT)

Personally i think it is marketing hype, i am not entirely convinced of global warming being as a direct result of CO emmissions

[Marks DTM Calib]

Just a note to all here.....as stated above....we are talking about efficient  

[Jay w]

Just a note to all here.....as stated above....we are talking about efficient  

that's me knackered then  

[Marks DTM Calib]

Just a note to all here.....as stated above....we are talking about efficient  

that's me knackered then  

Its a key thing.....and explains why it NEEDS to be a hybrid!

[Mr Skrunts]

Just a note to all here.....as stated above....we are talking about efficient  

Are you thinking of buying one Mark

It's not made by Sony so it might not be on TB's gay list..

On the effiency side I have no idea at all, all I know is that a lot of Hollywood stars own one to look and sound good in interviews but then drive round in thier 5.0 Mustang's.  :-/ :-/

[Entwood]

The biggest "inefficiency" in the internal combustion engine is the wasted energy in the form of exhaust heat, further inefficiencies for the car itself are things like brake heat.

AFAIK know the prius hybrid idea is to reduce these wastes as far as possible, so the electric side produces little waste heat, and the electric braking turns the kinetic energy back to electrics instead of heat ??

but as I know very little about the prius .. other than its a marketing hype .. I'm just guessing

[Marks DTM Calib]

A hint....from the engine theory

Opening the inlet valve
Earlier	Later
More power at higher rpm	Less power
More overlap with exhaust valve	More torque at lower rpm
Lower flexibility	Better emissions!
Poorer response at low rpm

Closing the inlet valve
Earlier	Later
Less power	More power at higher rpm
Higher compression ratio at low rpm	Compression ratio improves with higher rpm
Better torque	max. torque in higher rpm band
More flexible engine

Opening the exhaust valve
Earlier	Later
Less pumping losses, bit more power	More pumping losses,less power
Hotter outlet valve	More complete combustion, less emissions
More chance of pre-ignition	Lower exhaust temperature!

Closing the exhaust valve
Earlier	Later
Less overlap with inlet valve	Part of intake mixture goes straight into exhaust at lower rpm (engine is "Off cam")
More flexible engine at low rpm	More high end power
Less power at higher rpm	Less flexible engine at low rpm
More torque at low rpm	Low torque at lower rpm
Improved emissions

[Andy B]

erm, it isnt?

Well actually its mpg is not bad at all.....

Depends how you drive it.  OK the Top Gear skewed the 'test' but I thought the result was quite interesting.

http://uk.youtube.com/watch?v=N8XDscWleKw

[TheBoy]

Mr DTM, am I allowed to answer  

[Marks DTM Calib]

The answer is already above....highlighted!

So I guess so!