Flat-four Engine - Automobile Use

Automobile Use

Tatra introduced an air-cooled flat four engine in the 1926 Tatra 30, followed by the T52 of 1930, T54 of 1931, T57 in 1931, and T75 in 1933, all with air-cooled flat fours of varying displacement. The 1936 T97 model pioneered the rear-engined, air-cooled flat-four, backbone chassis layout, later copied by the Volkswagen KdF-Wagen.

Jowetts before the Second World War were best known for their flat twin engines, but they made a flat four for the Jason and 10 hp models in the 1930s. Post-war Gerald Palmer designed Javelin saloon and Jupiter sports models used a totally different design of flat four. Alec Issigonis originally designed the Morris Minor for a flat four, but cost constraints meant it was never used.

Volkswagen used air-cooled flat-4s extensively in their early days, in the VW Beetle and most early VW designs. Porsche also used the VW engine in the early Porsche 356. This engine was replaced by a Porsche designed flat-4 in the late 356s and the 912. The 914 that replaced the 912 was built in partnership with VW using a VW engine.

The Goliath 1100 appeared at the Geneva Motor Show in March 1957, with a water-cooled 1100 cc flat four driving the front wheels. In 1958 the name was changed to the Hansa 1100, and this car was produced through 1961.

VW used a water-cooled flat-4 Wasserboxer in the later third-generation Type 2 until 1991.

Citroën used an air-cooled flat-4 on the Ami Super, GS, GSA and Axel.

Water-cooled Alfa Romeo flat-4 was introduced in 1971 on the Alfa Romeo Alfasud. That engine was later used on the Alfa Romeo Arna, the Alfa Romeo 33, the Alfa Romeo Sprint and the Alfa Romeo 145/146.

Lancia used a water-cooled flat-4 on the Lancia Flavia and high-end Lancia Gamma.

Subaru produces a water-cooled front-mounted flat-4 engine marketed as H-4, by which they mean Horizontal rather than the H cross-section normally meant by H engine. Subaru has created a number of engines, starting with the EA series introduced in 1966, progressing towards the currently used EJ series, which is wide but very short and light, and is mounted ahead of the front axle with the transmission behind. With this layout, the gearbox can remain very similar to common transmissions in both design and weight without the need for a bulky and inefficient transfer case. Although it is more expensive than a straight-4, it allows Subaru to build an all-wheel drive vehicle at little extra cost over two-wheel drive.

A 2.0 L Flat-four engine with 200 hp having GDI was developed by a joint venture by Subaru (FA20) and Toyota (4U-GSE) for the two-door coupe Toyota 86.

Porsche announced in 2012 that they are developing a new 2.5-litre flat-4, their first flat-four since the 1970s Porsche 914.