Straight-five Engine

The straight-five engine or inline-five engine is an internal combustion engine with five cylinders aligned in one row or plane, sharing a single engine block and crankcase. This configuration is a compromise between the smaller inline-four engine and the larger straight-6.

Henry Ford had a inline-five engine developed in the late 1930s to early 1940s for a compact economy car design, which never saw production due to lack of demand for small cars in the United States. Consequently, a straight-five engine did not see production for passenger cars until Mercedes-Benz introduced the OM617 diesel in 1974. The first production petrol straight-five was the 2.1 R5 introduced by Volkswagen Group in the Audi 100 towards the end of the 1970s, developments of which powered the Audi Quattro rally racer. Since Volvo introduced their Volvo 850 in 1992, much of their lineup has switched to straight-five power, with their engines also seeing use in Ford's Focus ST and RS models. Honda used straight-fives in the Vigor, Inspire, Ascot, Rafaga, and Acura TL.

In the late 1990s, Rover Group developed an in-house straight-five diesel engine, the Td5, for the Discovery and Defender. Volkswagen has used straight-five engines in their Eurovan, and have recently developed a different straight-five engine which is used in the Jetta and Rabbit in North America. Fiat also makes use of straight-fives (both petrol and diesel) in larger Fiat, Alfa Romeo and Lancia models. General Motors has used Atlas-based straight-fives in their GMT 355 mid-size truck family since 2004.