One-third of car fuel consumption is due to friction loss

Jan 12, 2012

No less than one third of a car's fuel consumption is spent in overcoming friction, and this friction loss has a direct impact on both fuel consumption and emissions. However, new technology can reduce friction by anything from 10% to 80% in various components of a car, according to a joint study by VTT Technical Research Centre of Finland and Argonne National Laboratory (ANL) in USA. It should thus be possible to reduce car's fuel consumption and emissions by 18% within the next 5 to 10 years and up to 61% within 15 to 25 years.

There are 612 million cars in the world today. The average car clocks up about 13,000 km per year, and in the meantime burns 340 litres of fuel just to overcome friction, costing the driver EUR 510 per year.

Of the energy output of fuel in a , 33% is spent in exhaust, 29% in cooling and 38% in , of which friction losses account for 33% and air resistance for 5%. By comparison, an electric car has only half the friction loss of that of a car with a conventional .

Annual friction loss in an average car worldwide amounts to 11,860 MJ: of this, 35% is spent in overcoming rolling resistance in the wheels, 35% in the engine itself, 15% in the gearbox and 15% in braking. With current technology, only 21.5% of the of the fuel is used to actually move the car; the rest is wasted.

Worldwide savings with new technology

A recent VTT and ANL study shows that friction in cars can be reduced with new technologies such as new , , lubricant additives, low-viscosity lubricants, and low-friction tyres inflated to pressures higher than normal.

Friction can be reduced by 10% to 50% using new surface technologies such as diamond-like carbon materials and nanocomposites. Laser texturing can be employed to etch a microtopography on the surface of the material to guide the lubricant flow and internal pressures so as to reduce friction by 25% to 50% and by 4%. Ionic liquids are made up of electrically charged molecules that repel one another, enabling a further 25% to 50% reduction in friction.

In 2009, a total of 208,000 million litres of fuel was burned in cars worldwide just to overcome friction; this amounts to 7.3 million TJ (terajoules) of energy. Theoretically, introducing the best current technological solutions in all of the world's cars could save EUR 348,000 million per year; the best scientifically proven solutions known today could save EUR 576,000 million per year, and the best solutions to emerge over the next 10 years could save EUR 659,000 million per year.

Realistically, though, over a period of 5 to 10 years of enhanced action and product development measures could be expected to enable savings of 117,000 million litres in fuel consumption per year, representing an 18% reduction from the present level. Furthermore, in realistic terms, carbon dioxide emissions could be expected to decrease by 290 million tonnes per year and financial savings to amount to EUR 174,000 million per year in the short term.

Drivers can influence fuel consumption

A driver can significantly influence the fuel consumption of his or her car. A reduction of 10% in driving speed, e.g. from 110 km/h to 100 km/h, translates into a 16% saving in fuel consumption. Slower speeds also allow for higher tyre pressures; an increase from 2 bar to 2.5 bar can translate into a 3% saving in fuel consumption.

VTT and ANL calculated friction loss in cars worldwide using a method that incorporated total crude oil consumption and fuel consumption of cars, the energy consumption of an average car, and the energy that an average car uses to overcome friction.

Friction losses were accounted for in the subsystems of a – tyres, engine, gearbox, brakes – and also in its components, such as gears, bearings, gaskets and pistons. The friction losses caused at friction points and lubrication points were also considered.

The study was conducted at the Metal Products and Mechanical Engineering strategic competence cluster in the DEMAPP programme, co-ordinated by FIMECC Oy, where practical solutions for minimising friction loss are also being developed. The study was funded by the Finnish Funding Agency for Technology and Innovation (Tekes), VTT and FIMECC Oy, and the Argonne National Laboratory, Department of Energy (Chicago, USA).

Explore further: A platform to help consumers achieve sustainable energy consumption

More information: Tribology International DOI:10.1016/j.triboint.2011.11.022

Provided by VTT Technical Research Centre of Finland

4.3 /5 (17 votes)

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User comments : 9

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thuber
1 / 5 (2) Jan 12, 2012
Projections like this are useless propaganda. Publish the article after the coatings have been tested and manufactured.
El_Nose
5 / 5 (1) Jan 12, 2012
no this is useless because it will make the car cost 100k --- there is a trade off in everything and in this case it's just how much do you wanna pay for your tires -- or an average car part when it breaks
Eric_B
5 / 5 (2) Jan 12, 2012
uhhh....low-friction tires?

you try them first!
Scottingham
not rated yet Jan 12, 2012
Eric, I thought the same thing!
Pkunk_
1 / 5 (1) Jan 12, 2012
In 2009, a total of 208,000 million litres of fuel was burned in cars worldwide just to overcome friction; this amounts to 7.3 million TJ (terajoules) of energy. Theoretically, introducing the best current technological solutions in all of the world's cars could save EUR 348,000 million per year; the best scientifically proven solutions known today could save EUR 576,000 million per year, and the best solutions to emerge over the next 10 years could save EUR 659,000 million per year.


Sounds like someone was real busy with a calculator during this part of the report. Actually , these figures look like something pulled right out of someone's ...

Eikka
not rated yet Jan 12, 2012
Sounds to me like the result would be really fragile, like holding a house up with a single optimally placed matchstick.

If you laser in a carbon-infused nanopattern on the cylinder wall, how many miles until it simply wears off and the benefits are lost? Can you even touch the car with regular tools without ruining the fuel savings, or do you need to tighten the bolts using precision robotic wrenches to get them to exactly 120.5 Nm of torque?
Xbw
Jan 12, 2012
This comment has been removed by a moderator.
dschlink
not rated yet Jan 12, 2012
Reducing the size of the engine by 50% can increase mileage 25%, due to reduced part count and internal friction, less waste heat due to operating closer to design maximum, lower weight, lighter transmissions, etc. If the average horsepower of a car had remained constant over the last 30 years, cars would be getting 15-30% better mileage due to improvements in engine and combustion technology.
wealthychef
not rated yet Jan 12, 2012
Projections like this are useless propaganda. Publish the article after the coatings have been tested and manufactured.


You must be new here. LOL
88HUX88
not rated yet Jan 13, 2012
and you use (waste) more energy the faster you go, try limiting speed and see how that works, it wouldn't sell because joe public wants POWER and SPEED and to hell with everything else. Instead we will have hell on earth a few years down the line.