Improving fuel economy - Revision history

Jmdonev: 1 revision imported

2021-10-15T19:13:39Z

1 revision imported

← Older revision	Revision as of 19:13, 15 October 2021
(No difference)

energy>Jmdonev at 21:43, 27 May 2021

2021-05-27T21:43:07Z

← Older revision		Revision as of 21:43, 27 May 2021
Line 1:		Line 1:
	[[Category:Done ~~2018~~-08-03]]		[[Category:Done 2021-01-31]]
	[[File:tyre-pressure-tread-wear-tyre-tracks-comparison.jpg\|300px\|thumbnail\|A slightly deflated tire can worsen the fuel economy (make it a large value). It is important for cars to always have properly inflated tires as it also makes a difference in how the tire threads wear.<ref>Image taken from: http://www.tyresizecalculator.com/tyres/tyre-pressure, accessed May 18th, 2018.</ref>]]		[[File:tyre-pressure-tread-wear-tyre-tracks-comparison.jpg\|300px\|thumbnail\|A slightly deflated tire can worsen the fuel economy (make it a large value). It is important for cars to always have properly inflated tires as it also makes a difference in how the tire threads wear.<ref>Image taken from: http://www.tyresizecalculator.com/tyres/tyre-pressure, accessed May 18th, 2018.</ref>]]
	<onlyinclude>'''Improving fuel economy''' refers to the attempt to achieve a better [[fuel economy]] through a variety of means in a vehicle in an attempt to save money and reduce emissions.</onlyinclude> To learn about technical ways car manufacturers are trying to create cars with a greater ability to use fuel efficiently, please see [[kinetic energy recovery system]]s, or [[regenerative braking]].		<onlyinclude>'''Improving fuel economy''' refers to the attempt to achieve a better [[fuel economy]] through a variety of means in a vehicle in an attempt to save money and reduce emissions.</onlyinclude> To learn about technical ways car manufacturers are trying to create cars with a greater ability to use fuel efficiently, please see [[kinetic energy recovery system]]s, or [[regenerative braking]].

	~~People commonly~~ talk about ~~conserving~~ [[energy~~]], but the [[~~conservation of energy]] ~~is unavoidable since~~ it~~'s a physical law! This page discusses ways to conserve (use~~ less) [[fuel]] (usually [[gasoline]])~~; reducing~~ fuel use in cars saves money as well as reducing environmental impact.		To be clear, when people talk about [[Conserving energy vs conservation of energy\|conserving energy]], it really means using less [[fuel]] (usually [[gasoline]]). Reducing fuel use in cars saves money as well as reducing environmental impact. The [[conservation of energy]] is different, that means that energy can't be created or destroyed, it can only change forms.

	==Speed==		==Speed==
Line 11:		Line 11:
	In a similar vein, limiting rapid [[acceleration]] is an excellent way to conserve fuel. In most cases, when the [[engine]] is in [[gear]], economy relates to how fast the wheels are turning—faster turning wheels can go farther distances. Modern car engines (approximately year 2000 and up) will not use any fuel at all when the gas pedal isn't being pressed and the vehicle is rolling. This means that when driving down a hill, removing foot pressure from the accelerator will cause the engine not use any fuel at all. However, floor it, and the injectors will insert the maximum amount of fuel.		In a similar vein, limiting rapid [[acceleration]] is an excellent way to conserve fuel. In most cases, when the [[engine]] is in [[gear]], economy relates to how fast the wheels are turning—faster turning wheels can go farther distances. Modern car engines (approximately year 2000 and up) will not use any fuel at all when the gas pedal isn't being pressed and the vehicle is rolling. This means that when driving down a hill, removing foot pressure from the accelerator will cause the engine not use any fuel at all. However, floor it, and the injectors will insert the maximum amount of fuel.

	An exception to this rule is at idling speeds, even if the pedal isn't being pressed the vehicle must burn fuel to keep the engine from stalling while sitting still. ~~This means that~~ turning off a car's engine while waiting ~~for someone~~ at the side of the road ~~will~~ save fuel~~, but don't turn off~~ the engine at a stop light~~, that~~ could cause a bad car accident!		An exception to this rule is at idling speeds, even if the pedal isn't being pressed the vehicle must burn fuel to keep the engine from stalling while sitting still. Consider turning off a car's engine while waiting at the side of the road to save fuel; however turning the engine off while idling at a stop light could cause a bad car accident.

	==Engine speed==		==Engine speed==

Jmdonev: 1 revision imported

2018-09-03T22:23:36Z

1 revision imported

← Older revision	Revision as of 22:23, 3 September 2018
(No difference)

energy>Jmdonev at 02:35, 13 August 2018

2018-08-13T02:35:24Z

New page

[[Category:Done 2018-08-03]]
[[File:tyre-pressure-tread-wear-tyre-tracks-comparison.jpg|300px|thumbnail|A slightly deflated tire can worsen the fuel economy (make it a large value). It is important for cars to always have properly inflated tires as it also makes a difference in how the tire threads wear.<ref>Image taken from: http://www.tyresizecalculator.com/tyres/tyre-pressure, accessed May 18th, 2018.</ref>]]
<onlyinclude>'''Improving fuel economy''' refers to the attempt to achieve a better [[fuel economy]] through a variety of means in a vehicle in an attempt to save money and reduce emissions.</onlyinclude> To learn about technical ways car manufacturers are trying to create cars with a greater ability to use fuel efficiently, please see [[kinetic energy recovery system]]s, or [[regenerative braking]].

People commonly talk about conserving [[energy]], but the [[conservation of energy]] is unavoidable since it's a physical law! This page discusses ways to conserve (use less) [[fuel]] (usually [[gasoline]]); reducing fuel use in cars saves money as well as reducing environmental impact.

==Speed==
Certain factors like a car's brakes and shape affect fuel economy. It is possible to install improved brakes, but the cost-benefit trade off is usually not worth it. However, where and how the driver operates the vehicle also affects the economy. During highway driving, [[power]] output correlates to the [[air drag]]. This drag is due to the [[air drag#Drag coefficient|drag coefficient]] (a constant for a particular shape) multiplied by the [[velocity]] cubed. This means that slowing down by 10% uses 27% less power from the engine!<ref><math>\frac{P_{final}}{P_{initial}}\times100\% = \frac{1/2AC_d(0.9v)^3}{1/2AC_d v^3}\times100\%=73\%</math> which is 27% less power. Keep in mind that while this also means less energy is used, more time is spent using the energy. It's still an improvement (about 18% instead of 27%), but not as strong of one, please see [[energy vs power]].</ref> This does not mean that people should drive everywhere at 30 [[kph]], but at the same time, it does mean that in fifth gear while driving on the highway, considerably better fuel economy can be achieved in most cars by slowing down just a bit (going 120 kph uses 70% more power than going 100 kph).

==Acceleration==
In a similar vein, limiting rapid [[acceleration]] is an excellent way to conserve fuel. In most cases, when the [[engine]] is in [[gear]], economy relates to how fast the wheels are turning—faster turning wheels can go farther distances. Modern car engines (approximately year 2000 and up) will not use any fuel at all when the gas pedal isn't being pressed and the vehicle is rolling. This means that when driving down a hill, removing foot pressure from the accelerator will cause the engine not use any fuel at all. However, floor it, and the injectors will insert the maximum amount of fuel.

An exception to this rule is at idling speeds, even if the pedal isn't being pressed the vehicle must burn fuel to keep the engine from stalling while sitting still. This means that turning off a car's engine while waiting for someone at the side of the road will save fuel, but don't turn off the engine at a stop light, that could cause a bad car accident!

==Engine speed==
When at a constant cruising speed in a Mazda Protege, for example, the highest fuel economy (although it should usually be measured miles per gallon) is at around 3000 [[RPM]]. This is because the engine converts the fuel to work more efficiently, meaning it requires less fuel to run at 3000 RPM than it does at 1200 RPM. The same holds true for most small cars and can be tested with a manual transmission by driving at a set speed in two different gears. See how far down the pedal needs to be pressed when both accelerating and maintaining speed in the different gears. The closer to the floor the gas pedal is, the more fuel it is injecting into the engine, so it is possible to tell which gear is using more fuel (i.e the one with the least amount of foot pressure). Furthermore, more modern vehicles have gauges that denote exactly how much fuel is being consumed at any given time making it much easier to find the optimal cruising speed or RPM for differing vehicles.

==Tire pressure==
Perhaps it doesn't seem like it matters much, but where a vehicle comes in contact with the road—the wheels— is highly important for fuel economy. The EPA estimates that fuel economy can improve by up to 3.3% by having properly [[pressure|inflated]] tires, thus decreasing [[rolling resistance]] between the tires and the road.<ref name=A>http://www.fueleconomy.gov/feg/maintain.jsp</ref> This is true for anything with wheels—even peddling a bike with deflated tires is extremely difficult and requires much more energy. The only difference is where that energy comes from—most vehicles harness [[chemical energy]] by burning [[fossil fuel]]s, whereas a person peddling a bike harnesses energy by consuming [[food]]. To help quantify the difference in rolling resistance, notice how much slower a mountain bike rolls down a hill compared to a road bike.

[[File:proper_tire_inflation.jpg|800px|thumb|center|Properly inflated tires can improve fuel economy. They also help with safety, control, noise, and [[friction|traction]].<ref>Image and ideas taken from: https://www.tirebuyer.com/education/tire-pressure-and-performance, accessed May 18th, 2018.</ref>]]

== For Further Reading ==
For further information please see the related pages below:
*[[Regenerative braking]]
*[[Kinetic energy recovery system]]
*[[Friction]]
*[[Transportation energy use]]
*[[Electric vehicle]]
*Or explore a [[Special:Random|random page]]

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