HC Deb 04 November 1974 vol 880 c40W
Mr. Hooley

asked the Secretary of State for Energy what is the approximate percentage economy in fuel consumption of a diesel as compared with a petrol engine, weight for weight and power for power.

Mr. John Smith

Recent tests were carried out on behalf of the Department of Industry on two similar cars, one fitted with a petrol and the other with a diesel engine of comparable horse power, which were driven on a roller path dynamometer over a wide range of driving conditions. The saving in fuel was almost 20 per cent. in favour of the diesel-engined vehicle.