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Saving fuel by reducing friction

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, according to VTT new technology can reduce friction by anything from 10% to 80% in various components of a car, and thus save fuel.

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 car engine, 33% is spent in exhaust, 29% in cooling and 38% in mechanical energy, of which friction loss accounts for 33% and air resistance 5%. By comparison, an electric car has only half the friction loss of a car with a conventional internal combustion engine.

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.

A recent VTT study shows that friction in cars can be reduced with new technologies such as new surface materials, surface textures, lubricant additives, low-viscosity lubricants, ionic liquids and low-friction tyres inflated to pressures higher than normal. Friction can be reduced by 10% to 50% just by using new surface technologies such as diamond-like carbon or nanocomposites.

It should thus be possible to reduce car fuel consumption and emissions by 18% within 5 to 10 years and up to 61% within 15 to 25 years.


Additional information

Kenneth Holmberg
Research Professor
+358 20 722 7077

Additional information

Kenneth Holmberg
Research Professor
+358 20 722 7077