There are no standard methods or ways of classifying I.C. Engines.
They may be classified in many ways such as following:
(1) Arrangement of Engine Cylinders:
(i) Horizontal engine
(ii) Vertical engine
(iii) V engine
(iv) In-line engine
(v) Opposed cylinder engine
(vi) Opposed piston engine
(vii) Deltic engine
(viii) Y engine
(ix) Radial engine
(2) Working Cycle Employed:
(i) Four stroke cycle engine
(ii) Two stroke cycle engine
(3) Fuel Used:
(i) Petrol engine
(ii) Diesel engine
(iii) Gas engine
(iv) Bi-fuel engine
(4) Nature of Thermodynamic Cycle Used:
(i) Otto cycle engine
(ii) Diesel cycle engine
(iii) Dual combustion cycle engine.
(i) Low speed engine
(ii) Medium speed engine
(iii) High speed engine
(6) Method of Cooling:
(ii) Water cooled engine
(7) Field of Application:
(i) Stationary engine
(ii) Marine engine
(iii) Automobile engine
(iv) Motor-cycle engine
(v) Aero engine
(vi) Locomotive engine, etc.
(8) Method of Ignition:
(i) Compression ignition engine
(ii) Spark ignition engine.