RyanT
10 mW
Yeah same here. Over 70% or Oregon's power is from hydro and other renewables.
Tank to wheel efficiency for a gasoline car is very poor this is commonly known.Punx0r said:Take for example the tank to wheel efficiency of the gasoline car Vs. Prius hybrid. The disparity is huge (absurd, even) and suggests the test conditions (intentionally or otherwise) greatly preferred the hybrid.
Depends on the test method.Punx0r said:The tables posted above indicate 84% efficiency well-to-tank for gasoline.
EPA diesel engine testing, 43-49% efficiency: http://www.epa.gov/otaq/models/ngm/may04/crc0304c.pdf
Theory / indicated!
Resorting to Wikipedia, but...
Modern diesel cars peak efficiency of 45%
http://en.wikipedia.org/wiki/Diesel_engine#Fuel_economy
Gasoline direct injection cars, 35%
http://en.wikipedia.org/wiki/Engine_efficiency#Internal_combustion_engines
They are picking peaks on prototype / non commercial power plants in most cases.
Not a criticism, but figures like 20% might well be typical for the U.S. market where fuel efficiency is often of little concern, emissions restrictions can be strangling and with a preference for large-displacement engines with lots of low-down torque often results in engines with low specific outputs. ~1 litre, two or three cylinder diesel engines may be godawful but they are efficient
This isn't completely off-topic - I did see a few charts during general searching that suggested diesel hybrids were equal to, or slightly more efficient well-to-wheel than BEVs or hydrogen fuel cell vehicles. Who knows if the numbers were reliable, though![]()
speedmd said:They are picking peaks on prototype / non commercial power plants in most cases.
GM has a patent on that idea I read it once in a popular mechanics magazine.Punx0r said:I'm not spamming this thread, honestJust avoiding doing work at the moment...
A little while ago I had what I thought was a good idea: Use wasteheat from an ICE to create high pressure steam and drive another cylinder. I was seriously considering buying a 5 cylinder Audi to experiment with. The idea was to the reconfigure the petrol ICE to run on four cylinders, leaving the fifth for high pressure steam injection. The cooling system would be used to preheat the water, which would then be heated to high temperature and pressure by the exhaust. I figured that the petrol combustion might produce enough recoverable water to sustain the steam system.
It seemed like a great idea until I realised that a single expansion, non-condensing steam piston "engine" like this would probably be about 1-2% efficient. So using the ~70% waste heat generated by the ICE the overall efficiency boost to the entire system might be 1% :faceplam:
I still suspect the Prius would be more efficient with a diesel engine. If there's a reason Toyota went with petrol other than U.S. market acceptance I'd love to know![]()