Final answer:
In an internal combustion engine, a gas undergoes processes such as intake, compression, power, and exhaust strokes in a piston-cylinder, transferring heat into work through adiabatic and isobaric processes.
Step-by-step explanation:
A gas undergoes various processes in a piston-cylinder assembly of an internal combustion engine, transforming heat transfer into work. The key processes include the intake stroke, compression stroke, power stroke, and exhaust stroke, as part of the idealized Otto cycle.
Intake Stroke
During the isobaric intake stroke, an air-fuel mixture enters the cylinder at constant atmospheric pressure, increasing its volume.
Compression Stroke
The adiabatic compression stroke involves compressing the mixture without heat transfer, increasing its pressure and temperature as work is done on the gas.
Power Stroke
The mixture is ignited, significantly increasing pressure. The gas then does work on the piston during its descent in another adiabatic process.
Exhaust Stroke
The hot gases are expelled, prepping the engine for the next cycle.
An isothermal process may also occur where the temperature remains constant, balancing internal and external pressures, while changes in gas volumes affect the pressure.
Adiabatic processes are characterized by no heat exchange with the surroundings, where a change in gas volume impacts both pressure and temperature, with the internal energy converted into work.