Wankle a. : Not to be depended on; weak; unstable.

Example:
can u tell me more about Wankle engine, and its designation?

Taxonomy
Wankel engine, rotor, Wankel, piston engine, housing, Wankel engines, Rotary Engine, Mazda, design, displacement, Wankel rotary engine, engines, power, power stroke, rotary, combustion chamber, aircraft, eccentric shaft.

Defination from the web:
... Its four-stroke cycle takes place in a space between the inside of an oval-like epitrochoid-shaped housing and a rotor that is similar in shape to a Reuleaux triangle. ...