The Citroën 2CV (French: "deux chevaux" i.e. "deux chevaux-vapeur" (lit. 'steam horses'), "two tax horsepower") was an economy car produced by the French car manufacturer Citroën between 1948 and 1990.
ENGINES
The engine was designed by Walter Becchia and Lucien Gerard,[3] with a nod to the classic "boxer" BMW motorcycle engine (it is reported that Becchia dismantled the engine of the BMW motorcycle of Flaminio Bertoni before designing the 2CV engine). It was an air-cooled, flat-twin, four-stroke, 375 cc engine with pushrod operated overhead valves and a hemispherical combustion chamber. The notoriously underpowered earliest model developed only 9 bhp DIN (6.5 kW).
A 425 cc engine was introduced in 1955, followed in 1968 by a 602 cc one giving 28 bhp (21 kW) at 7,000 rpm. With the 602 cc engine, the tax classification of the car changed so that it became in fact a 3CV, but the commercial name remained unchanged. A 435 cc engine was introduced at the same time in replacement of the 425 cc; the 435 cc engine car was christened 2CV 4 while the 602 cc took the name 2CV 6 (although a variant did take the name 3CV in Argentina). The 602 cc engine evolved to the M28 33 bhp (25 kW) in 1970; this was the most powerful engine fitted to the 2CV. A new 602 cc giving only 29 bhp (22 kW) at a slower 5,750 rpm was introduced in 1979. Despite being less powerful, this engine was more efficient, allowing lower fuel consumption and better top speed, at the price of decreased acceleration.
source: wikipedia.org
