Quote:
Originally Posted by Deezler
Who the heck drives steady state 30mph anyway?
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The average speed of the EPA City cycle is 28 mph so 30 mph happens to be very close.
Quote:
Originally Posted by Deezler
I really don't understand how engine friction at 30 mph is a "problem".
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Because of the low vehicle power demands, ~5 hp, it can be treated as a constant for engines of similar displacement. So we don't really have to bother with "a function fo speed (rpm) primarily and load second." A steady speed eliminates another red herring.
Quote:
Originally Posted by Deezler
Saying 50% at 30mph is a very poor blanket statement.
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Actually it is fairly accurate in the case of vehicles that must run their engine to maintain a constant speed. As pointed out, the 5 hp starting motor power gives a good approximation of the engine, internal power loss at low power settings. To provide an equal amount of motive power, 30 mph requires pretty close to the extra 5 hp needed.
Quote:
Originally Posted by Deezler
I would be interested to compare the FE of a prius steady at 30mph vs. a diesel VW allowed to run P & G in the 25-35 range as well.....
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Actually I would like to see steady state, MPG vs mph for a diesel similar to what I already have for the Prius:
In the meanwhile, the EPA City ratings tell the tale when identical driving profiles are used:
- 29 MPG - Jetta diesel automatic
- 51 MPG - Prius 2010 automatic
But since P&G seems to posses cache (regardless of the traffic issues that limit its application,) I would be just as happy to see the Prius vs Diesel P&G contest. The reason is we have already run the NHW20 Prius at P&G averaging close to 30 mph:
Seriously, do diesel advocates really think they'll get in excess of 100-115 MPG as the Prius team did in August 2005?
Bob Wilson