Ideal Heat Engine Gas Cycles

IDEAL HEAT ENGINE GAS CYCLES Otto Cycle - Internal Combustion Engine

Compression Stroke. Adiabatic compression of gas fuel mixture in the cylinder. Ignition of gas fuel mixture. Take place rapidly at top of the compression stroke while the volume is essentially constant. Expansion Stroke. Adiabatic, isentropic expansion of gases in the cylinder after fuel mixture is ignited. This is the part of the cycle that does positive work. Exhaust of the spent gases and the intake of a new fuel mixture into the cylinder. The volume is the same at beginning and ending of the exhaust and intake stroke.

Diesel Cycle - Diesel Engine

Compression Stroke. Adiabatic compression of gas fuel mixture in the cylinder. Ignition of gas fuel mixture. Fuel is ignited by high temperature due a large compression. Burning takes places while the pressure is essentially constant. Expansion Stroke. Adiabatic, isentropic expansion of gases. This is the part of the cycle that does positive work. Exhaust of the spent gases and the intake of a new fuel mixture into the cylinder. The volume is the same at beginning and ending of the exhaust and intake stroke.

Stirling Cycle - Example of a Carnot Engine

Isothermal-compression compression of working gas.

Heat is absorbed from an energy-storage device at a constant volume. Isothermal-expansion of gases. This is the part of the cycle that does positive work. Heat is transferred from the working gas to an energy storage device at a constant pressure. The heat stored in this part of the cycle is the same as the heat absorbed in 2 -> 3 part of the cycle.

Brayton Cycle - Gas-Turbine Engine

Isentropic-compression of the intake air into the combustion section of the engine. Constant-pressure combustion of fuel injected into combustion chamber. Isentropic-expansion through the turbine section. This is the part of the cycle that does positive work. Constant-pressure heat is exhausting into the air.