Miles per gallon gasoline equivalent - Revision history

Jmdonev: 1 revision imported

2018-04-14T21:17:39Z

1 revision imported

← Older revision	Revision as of 21:17, 14 April 2018
(No difference)

Jmdonev at 06:06, 10 March 2018

2018-03-10T06:06:52Z

← Older revision		Revision as of 06:06, 10 March 2018
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	[[category:units]]		[[category:units]]
	[[Category:Done ~~2015~~-02-15]]		[[Category:Done 2017-12-31]]
	<onlyinclude>'''Miles per gallon gasoline equivalent''' refers to the [[fuel]] [[efficiency]] of electric vehicles that compares how far a [[transportation\|car]] can go with how much energy is in a gallon of gasoline.</onlyinclude> This measurement is misleading as efficiency for gasoline engines is radically different from electric motors. The measurement is an attempt to compare apples to oranges, as the challenges of fuel efficiency for a [[heat engine]]-powered car are completely different from the challenges of energy efficiency for an electric [[electric vehicle]].		<onlyinclude>'''Miles per gallon gasoline equivalent''' refers to the [[fuel]] [[efficiency]] of electric vehicles that compares how far a [[transportation\|car]] can go with how much energy is in a gallon of gasoline.</onlyinclude> This measurement is misleading as efficiency for gasoline engines is radically different from electric motors. The measurement is an attempt to compare apples to oranges, as the challenges of fuel efficiency for a [[heat engine]]-powered car are completely different from the challenges of energy efficiency for an electric [[electric vehicle]].

	When testing electric vehicles for fuel economy, the United States EPA uses a standard of 115,000 [[BTU]] of energy per [[gallon]] (US) of [[gasoline]], which converts to 33.7 [[kWh]].<ref>http://www.edmunds.com/fuel-economy/decoding-electric-car-mpg.html</ref>		When testing electric vehicles for fuel economy, the United States EPA uses a standard of 115,000 [[BTU]] of energy per [[gallon]] (US) of [[gasoline]], which converts to 33.7 [[kWh]].<ref>http://www.edmunds.com/fuel-economy/decoding-electric-car-mpg.html</ref>

	<math>115,000 BTU \times \frac{1055 J}{1 BTU}\times \frac{~~1kWh~~}{3,600,000 J}= 33.7 kWh</math>		::<math>115,000 BTU \times \frac{1055 \text{ J}}{1 \text{ BTU}}\times \frac{1 \text{ kWh}}{3,600,000 \text{ J}}= 33.7\text{ kWh}</math>

	This result is misleading because kWh implies [[end use energy]]. Technically, gasoline is part of end use energy (it's a [[secondary fuel]]), but gasoline's energy is measured as [[heat]] not [[work]]. This gives electric vehicles an artificially good efficiency (usually by about a factor of 3). This idea is explained in more detail on the page [[energy loss]].		This result is misleading because kWh implies [[end use energy]]. Technically, gasoline is part of end use energy (it's a [[secondary fuel]]), but gasoline's energy is measured as [[heat]] not [[work]]. This gives electric vehicles an artificially good efficiency (usually by about a factor of 3). This idea is explained in more detail on the page [[energy loss]].
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	To get an actual number for our MPGe, someone measures how many kWh the electric vehicle uses to travel 100 miles. This is then converted to the final MPGe measurement. For example, if an electric vehicle uses 29 kWh to travel 100 miles:		To get an actual number for our MPGe, someone measures how many kWh the electric vehicle uses to travel 100 miles. This is then converted to the final MPGe measurement. For example, if an electric vehicle uses 29 kWh to travel 100 miles:

	<math>\frac{100 \~~textrm~~{ miles}}{29 \~~textrm~~{ kWh}} \times \frac{33.7 kWh}{1 gallon of gasoline} = 116.2 </math> ~~MPGe~~.		::<math>\frac{100 \text{ miles}}{29\text{ kWh}} \times \frac{33.7\text{ kWh}}{1\text{ gallon of gasoline}} = 116.2\text{ MPGe} </math>.

	Note that this is roughly 3x a normal fuel efficiency for a car (38 mpg). That's because an [[internal combustion engine]] has waste heat that accounts for 2/3 of the energy in the car!		Note that this is roughly 3x a normal fuel efficiency for a car (38 mpg). That's because an [[internal combustion engine]] has waste heat that accounts for 2/3 of the energy in the car!

Jmdonev at 06:15, 23 December 2017

2017-12-23T06:15:26Z

← Older revision		Revision as of 06:15, 23 December 2017
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	To get an actual number for our MPGe, someone measures how many kWh the electric vehicle uses to travel 100 miles. This is then converted to the final MPGe measurement. For example, if an electric vehicle uses 29 kWh to travel 100 miles:		To get an actual number for our MPGe, someone measures how many kWh the electric vehicle uses to travel 100 miles. This is then converted to the final MPGe measurement. For example, if an electric vehicle uses 29 kWh to travel 100 miles:

	<math>\frac{100 \textrm{miles}}{29 \textrm{kWh}} \times \frac{33.7 kWh}{1 gallon of gasoline} = 116.2 </math> MPGe.		<math>\frac{100 \textrm{ miles}}{29 \textrm{ kWh}} \times \frac{33.7 kWh}{1 gallon of gasoline} = 116.2 </math> MPGe.

	Note that this is roughly 3x a normal fuel efficiency for a car (38 mpg). That's because an [[internal combustion engine]] has waste heat that accounts for 2/3 of the energy in the car!		Note that this is roughly 3x a normal fuel efficiency for a car (38 mpg). That's because an [[internal combustion engine]] has waste heat that accounts for 2/3 of the energy in the car!

Jmdonev at 06:15, 23 December 2017

2017-12-23T06:15:03Z

← Older revision		Revision as of 06:15, 23 December 2017
Line 11:		Line 11:
	To get an actual number for our MPGe, someone measures how many kWh the electric vehicle uses to travel 100 miles. This is then converted to the final MPGe measurement. For example, if an electric vehicle uses 29 kWh to travel 100 miles:		To get an actual number for our MPGe, someone measures how many kWh the electric vehicle uses to travel 100 miles. This is then converted to the final MPGe measurement. For example, if an electric vehicle uses 29 kWh to travel 100 miles:

	<math>\frac{100 miles}{29 kWh} \times \frac{33.7 kWh}{1 gallon of gasoline} = 116.2 </math> MPGe.		<math>\frac{100 \textrm{miles}}{29 \textrm{kWh}} \times \frac{33.7 kWh}{1 gallon of gasoline} = 116.2 </math> MPGe.

	Note that this is roughly 3x a normal fuel efficiency for a car (38 mpg). That's because an [[internal combustion engine]] has waste heat that accounts for 2/3 of the energy in the car!		Note that this is roughly 3x a normal fuel efficiency for a car (38 mpg). That's because an [[internal combustion engine]] has waste heat that accounts for 2/3 of the energy in the car!

Jmdonev at 22:06, 22 November 2017

2017-11-22T22:06:27Z

← Older revision		Revision as of 22:06, 22 November 2017
Line 1:		Line 1:
	[[category:units]]		[[category:units]]
	[[Category:Done 2015-02-15]]		[[Category:Done 2015-02-15]]
	<onlyinclude>'''Miles per gallon gasoline equivalent''' refers to the fuel efficiency of electric vehicles that compares how far a car can go with how much energy is in a gallon of gasoline.</onlyinclude> Is is ~~a slightly arbitrary measurement,~~ as efficiency for gasoline engines is radically different from electric motors. It is an attempt to compare apples to oranges, as the challenges of fuel efficiency for a heat engine-powered car are completely different from the challenges of energy efficiency for an electric ~~car~~.		<onlyinclude>'''Miles per gallon gasoline equivalent''' refers to the [[fuel]] [[efficiency]] of electric vehicles that compares how far a [[transportation\|car]] can go with how much energy is in a gallon of gasoline.</onlyinclude> This measurement is misleading as efficiency for gasoline engines is radically different from electric motors. The measurement is an attempt to compare apples to oranges, as the challenges of fuel efficiency for a [[heat engine]]-powered car are completely different from the challenges of energy efficiency for an electric [[electric vehicle]].

			When testing electric vehicles for fuel economy, the United States EPA uses a standard of 115,000 [[BTU]] of energy per [[gallon]] (US) of [[gasoline]], which converts to 33.7 [[kWh]].<ref>http://www.edmunds.com/fuel-economy/decoding-electric-car-mpg.html</ref>

	~~When testing [[Electric vehicle]]s for fuel economy, the United States EPA uses a standard of~~ 115,000 [[BTU~~]] of energy per gallon of [[gasoline]]~~, ~~which converts to~~ 33.7 [[kWh~~]].<ref>http://www.edmunds.com/fuel-economy/decoding-electric-car-mpg.html~~</~~ref~~> ~~They then calculate a value for how much energy it takes the EV to travel 100 miles. To get the final MPGe measurement, they divide 33.7 kWh by the 100-mile energy use value, then multiply by 100.~~		<math>115,000 BTU \times \frac{1055 J}{1 BTU}\times \frac{1kWh}{3,600,000 J}= 33.7 kWh</math>

			This result is misleading because kWh implies [[end use energy]]. Technically, gasoline is part of end use energy (it's a [[secondary fuel]]), but gasoline's energy is measured as [[heat]] not [[work]]. This gives electric vehicles an artificially good efficiency (usually by about a factor of 3). This idea is explained in more detail on the page [[energy loss]].

	~~Nissan Leaf energy usage (~~kWh/100 ~~mi) = 29<sub>comb</sub>~~. ~~<m>MPG_e = 33~~.7/29 * 100 ~~= 116 MPG_e</m>~~		To get an actual number for our MPGe, someone measures how many kWh the electric vehicle uses to travel 100 miles. This is then converted to the final MPGe measurement. For example, if an electric vehicle uses 29 kWh to travel 100 miles:

			<math>\frac{100 miles}{29 kWh} \times \frac{33.7 kWh}{1 gallon of gasoline} = 116.2 </math> MPGe.

			Note that this is roughly 3x a normal fuel efficiency for a car (38 mpg). That's because an [[internal combustion engine]] has waste heat that accounts for 2/3 of the energy in the car!

	==References==		==References==
	{{reflist}}		{{reflist}}
	[[Category:Uploaded]]		[[Category:Uploaded]]

J.williams: 1 revision imported

2015-08-26T21:31:22Z

1 revision imported

← Older revision	Revision as of 21:31, 26 August 2015
(No difference)

J.williams at 16:56, 12 August 2015

2015-08-12T16:56:58Z

New page

[[category:units]]
[[Category:Done 2015-02-15]]
<onlyinclude>'''Miles per gallon gasoline equivalent''' refers to the fuel efficiency of electric vehicles that compares how far a car can go with how much energy is in a gallon of gasoline.</onlyinclude> Is is a slightly arbitrary measurement, as efficiency for gasoline engines is radically different from electric motors. It is an attempt to compare apples to oranges, as the challenges of fuel efficiency for a heat engine-powered car are completely different from the challenges of energy efficiency for an electric car.

When testing [[Electric vehicle]]s for fuel economy, the United States EPA uses a standard of 115,000 [[BTU]] of energy per gallon of [[gasoline]], which converts to 33.7 [[kWh]].<ref>http://www.edmunds.com/fuel-economy/decoding-electric-car-mpg.html</ref> They then calculate a value for how much energy it takes the EV to travel 100 miles. To get the final MPGe measurement, they divide 33.7 kWh by the 100-mile energy use value, then multiply by 100.

Nissan Leaf energy usage (kWh/100 mi) = 29<sub>comb</sub>. <m>MPG_e = 33.7/29 * 100 = 116 MPG_e</m>

==References==
{{reflist}}
[[Category:Uploaded]]