Carl Eugen Langen (9 October 1833 – 2 October 1895) was a German entrepreneur, engineer and inventor, involved in the development of the petrol engine and the Wuppertal Suspension Railway.
In 1857 he worked in his father's sugar factory, JJ Langen & Söhne, and after extensive technical training at the Polytechnic institute in Karlsruhe, patented a method for producing sugar cubes.
He sold this method in 1872 by Sir Henry Tate of England, founder of the Tate Gallery in London.