Engines

Purpose of a heat engine :

• is a machine or system that converts heat into work

Is an internal combustion engine which uses a fuel outside the system as a source of heat energy.
Explain how heat energy is used to do work and also how the water is recycled back to the tank

• the water is heated to steam
• steam does work on the piston (friction) and is condensed
• the water is turned back into a liquid (energy is lost) and is heated (waste heat travels to the surroundings)
• the process repeated again when the water travels back to get heated again

—> the work done by a heat engine can be used to power many things

A model has been developed further and made more efficient to create an internal combustion engine. Explain why the above engine is not efficient.

• Heat is being lost to the surroundings when combustion occurs