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The goal of EPA mileage tests is to control all test conditions to be able to reliably compare different vehicles. The tests are run indoors, on a dynamometer, by professional drivers, with antiquated 55 mph era driving profiles. The maximum highway speed is 60 mph.
I drive my vehicle outdoors (has an average headwind of 7 mph), on a real road surface, I’m in a hurry to get home, so I gun the gas, there are other vehicles on the road so I have to speed up and down to accommodate them, I travel on a highway at 70 mph, and I have my A/C on. Normal driving can never give a result anywhere close to the EPA rating.
Using my dynamic model cruise range (See attachment) and assumptions for the Volt, I estimate that an average 7 mph headwind, a typical road surface, and A/C (accessory power increased from 100W to 700W) would each reduce Single Charge range @45mph by 15%, 7.7%, and 14% respectively. The combined effect (not the simple sum of individual components) is a 30% reduction. If I increase the profile speed by 5 mph to 50 mph, the total reduction is 36%. A 40 mile EPA rating translated to the real world is estimated to reduce the single charge rating to 25.6 miles. If anybody has a better way of doing this estimate, let me know.
For example, see http://www.wired.com/cars/futuretransport/news/2007/05/hybrid_mpg
Tom
I drive my vehicle outdoors (has an average headwind of 7 mph), on a real road surface, I’m in a hurry to get home, so I gun the gas, there are other vehicles on the road so I have to speed up and down to accommodate them, I travel on a highway at 70 mph, and I have my A/C on. Normal driving can never give a result anywhere close to the EPA rating.
Using my dynamic model cruise range (See attachment) and assumptions for the Volt, I estimate that an average 7 mph headwind, a typical road surface, and A/C (accessory power increased from 100W to 700W) would each reduce Single Charge range @45mph by 15%, 7.7%, and 14% respectively. The combined effect (not the simple sum of individual components) is a 30% reduction. If I increase the profile speed by 5 mph to 50 mph, the total reduction is 36%. A 40 mile EPA rating translated to the real world is estimated to reduce the single charge rating to 25.6 miles. If anybody has a better way of doing this estimate, let me know.
For example, see http://www.wired.com/cars/futuretransport/news/2007/05/hybrid_mpg
Tom
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