What term describes any engine in which the working medium is the products of combustion of the air and fuel supplied?

• A. Internal Combustion Engine
• B. External Combustion Engine
• C. Hybrid Engine
• D. Electric Motor

Answer: (A)

In an internal combustion engine, the energy-producing working fluid is the hot, high-pressure gases created by burning fuel with air inside the engine itself. The combustion products expand and push the piston or turbine blades, turning into mechanical work directly within the engine’s cylinders or chambers. This is what distinguishes it from other types.

External combustion engines rely on a separate working fluid (like steam) heated by combustion occurring outside the engine; the engine uses that external fluid to do the work, not the combustion exhaust gases inside the engine. A hybrid engine combines an internal combustion source with another energy source (such as an electric motor), but the fundamental mechanism of the internal combustion portion still uses the combustion gases as the working medium. An electric motor, on the other hand, uses electricity to produce motion, with no combustion gases acting as the working medium.

So the term that describes an engine where the working medium is the products of combustion is internal combustion engine.