Engine downsizing

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Engine downsizing is the use of a smaller engine in a vehicle that provides the power of a larger engine, through the use of recent technologies. It is the result of car manufacturers attempting to provide more efficient vehicles.[1] The term generally relates to traditional internal combustion engines powered by petrol or diesel.

Many manufacturers are reducing engine capacity and number of cylinders. By adding a boosting device (turbocharger or supercharger) and direct injection technology, they provide a powerful engine with similar performance to a much larger engine, but with much improved efficiency and reduced carbon emissions. A smaller engine is also often lighter, so the car can be lighter and therefore nimbler.

Some observers have not been convinced by manufacturer's claims that reducing engine size provides a more efficient car.[2]

Recent research and progress[edit]

The University of Bath published research carried out by its Powertrain and Vehicle Research Centre which demonstrated that it is possible to reduce engine capacity by 60% and still achieve the torque curve of a modern, large-capacity naturally-aspirated engine, while encompassing the attributes necessary to employ such a concept in premium vehicles.[3]


The Volkswagen Group replaced their 1.6 and 2.0 litre gasoline engines in the late 2000s with the 1.4 TSI unit. It was launched at the 2005 Frankfurt Motor Show in a 125 kW (170 PS) version using both a turbocharger and a supercharger. Its fuel consumption was 5% lower than the previous 2.0 FSI, despite the increased horsepower throughout the revving range. Later the engine was sold in several versions from 122 to 180 PS, some of them with only the turbocharger.

In Europe, Ford launched their new EcoBoost three-cylinder 1-litre engine to the Ford Focus in 2012, to replace the 1.6-litre and producing the same 123 bhp (92 kW; 125 PS).[4]


  1. ^ Squatriglia, Chuck (16 September 2011). "Three Is the New Four as Engines Downsize". Wired. Retrieved 12 February 2012. 
  2. ^ "Engine Displacement Downsizing Where's the fuel-economy gain?". Car and Driver. July 2009. Retrieved 12 February 2012. 
  3. ^ Lewis, A.G.J. (1 April 2014). ""Ultra Boost for Economy: extending the limits of extreme engine downsizing"". SAE International Journal of Engines. Retrieved 8 July 2014. 
  4. ^ Simister, John (February 2012). "Driven: Ford Focus 1.0 Ecoboost". Car Magazine. Retrieved 12 February 2012.