Mazda Wankel engine

All Mazda Wankel engines (a type of rotary combustion engine) are essentially a single family they all derive from experiments in the early 1960s by Felix Wankel, a German engineer. Over the years, displacement has been increased somewhat and turbocharging has been added to great effect. Wankel engines can be classified by their geometric size in terms of radius (rotor center to tip distance, also the median stator radius) and depth (rotor thickness), and offset (crank throw, excentricity, also 1/4 the difference between stator's major and minor axes). These metrics function similarly to the bore and stroke measurements of a piston engine. Displacement is 3 3radius·offset·depth, multiplied with the number of rotors. Nearly all Mazda production Wankel engines share a single rotor radius, 105 mm (4.1 in), with a 15 mm (0.6 in) crankshaft offset. The only engine to diverge from this formula was the rare 13A, which used a 120 mm (4.7 in) rotor radius and 17.5 mm (0.7 in) crankshaft offset.