Traditional cars have an efficiency of 10 -30 %. Anyone know what the efficiency of a Gen III Prius is?
I think he is saying that typical internal combustion engine vehicles use only 10-30% of the energy available from the fuel because of factors like weight, friction of gears, aerodynamics, etc. He is asking if the Prius wastes less of this energy. I'd say yes, just based on the fact that a Prius gets 50mpg while a similarly sized car typically gets around 25-30mpg. But I don't know the calculations to figure out exactly how much more efficient it is.
Well let's start with two cars: 2.2L Chevy Cobalt - 27 MPG 1.8L Prius 2010 - 50 MPG So given the terrific Chevy advertisements about how efficient they are, we can establish the following ratio:30% -> 27 MPG :: Chevy Cobalt efficiency per MPG increase MPG by 1.85, also changes efficiency 56% -> 50 MPG :: Chevy Cobalt efficiency increase to match Prius 56% -> 50 MPG :: Prius efficiency Of course there are other ways and vehicle with which do such "analysis" but this is just for fun. Bob Wilson
http://priuschat.com/forums/gen-iii...2010-prius-2zr-fxe-engine-efficiency-map.html The BSFC data is less than 220g/kWh, which translates the efficiency is better than 35%. Ken@Japan
Hi All, When talking about cars and efficiency, there are several "efficiencies". Engine efficiency is one. But, there is also car system efficiency. The engine efficiency is variable depending on load and RPM. Its measured in what is called a BSFC map. Do a search on PC of BSFC for all sorts of info. This is a measurement of how much shaft energy comes out the crank shaft, for how much fuel is consumed. The car system efficiency depends on engine efficiency, and doubling engine efficiency will double car system efficiency. Car system efficiency, is how much transportation is achieved per fuel energy consumed. The EPA test is a metric of car system efficiency. But there are other ways to improve car system efficiency too. Appropriate sized tires with good rolling resistance, better Coefficient of Aerodynamic Drag are two. But also hybridization, which allows recovery of height potential energy and kinetic energy through regenerative braking. Hybridisation allows the use of a smaller engine for vehicle size and accelleration requirements. Which allows the engine to run in its best portions of the BSFC map. And of course full hyrbridisation allows the engine to be turned off while the car runs along down slope. Which saves fuel energy consumption.
