Straight-3
A Straight-3 is an internal combustion engine with three cylinders arranged in a straight line side by side.
The straight-3 employs a crank angle of 120° and is thus rotationally balanced; however, since the three cylinders are offset from each other the firing of the end cylinders induces a rocking motion from end to end. The use of a balancing shaft with counterbalancing weights that work in antiphase to that vibration produces a smoothly running engine.
The straight-3 is the smallest engine in use in modern cars, generally for displacements of 1 litre and under. Cars in the 'super-mini' class often use them on base models, as do the Japanese Keicars. A straight-3 is also used in the Suzuki Swift and they were used in two stroke Saabs 93 - 96. One experimental Saab had two transverse straight-3 engines, the Saab Monster.
See Also
Straight engine
