The Collaborative International Dictionary of English v.0.48:

Diesel \Diesel\, Diesel engine \Die"sel en`gine\ or Diesel motor
\Die"sel mo`tor\ (d[=e]"zel). [After Dr. Rudolf Diesel, of
   Munich, the inventor.]
   A type of internal-combustion engine in which the air drawn
   in by the suction stroke is so highly compressed that the
   heat generated ignites the fuel (usually a heavy oil), the
   fuel being automatically sprayed into the cylinder under
   pressure. The Diesel engine has a very high thermal
   efficiency.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

Diesel
    n 1: German engineer (born in France) who invented the diesel
         engine (1858-1913) [syn: Diesel, Rudolf Diesel, Rudolf
         Christian Karl Diesel]
    2: an internal-combustion engine that burns heavy oil [syn:
       diesel, diesel engine, diesel motor]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

DIESEL
       Dumb Interpretatively Evaluated String Expression Language
(carCAD)