Internal Combustion Engine

Classifications of Engines

• The External combustion Engine.

• The Internal combustion Engine.

E.C.E (external combustion engine)

It is any engine that operates by

burning its fuel outside the engine.

engine is one in which the heat transfer to the working fluid occurs within the engine itself, usually by the combustion of fuel with the oxygen of air.

inner dead centre (IDC) outer dead centre(ODC),

air & fuel combustion

compresses

compression temperature & pressure very high

high temperature apply force move piston

exhaust

• It has no valves or camshaft mechanism.

• Less weight and easier to manufacture.

• High power to weight ratio.

• the 2-stroke engines have shorter life.

• They do not consume fuel efficiently.

• They produce lots of pollution.

• Sometimes part of the fuel leaks to the exhaust with the exhaust gases.

• Induction or Fuel Admission or Intake Stroke

• Compression Stroke

• Expansion or Power Stroke

• Exhaust Stroke

.

6-STROKE ENGINE

reduced by more than 40%

2-Stroke Working

4-Stroke Working

Strokes: Suction Stroke

Compression Stroke Ignition Stroke

Exhaust Stroke Air Suction Stroke

Air Exhaust Stroke

Valves: Suction Valve Air Inlet Valve Exhaust Valve Air Exhaust Valve

Valve 1 is open for gases inlet

Valve 2 is open for gases inlet in outer part of combustion chamber

Valve 3 is open for gases inlet from comustion chamber to gases chamber

Valve 4 is open for gases outlet in atmosphere

Valve 2 is open for gases outlet in hollow gaseous chamber

Valve 3 is open for gases inlet in combustion chamber

Basic DefinAtions

The process takes place from initiation to completion without an increase or decrease in the entropy of the system, i.e., the entropy of the system remains constant.

The process in which no heat leaves or enters the system ( either in expansion or compression ) is called Adiabatic Process.

The process in which the volume of the system remains constant even the pressure is increased or decreased is called Isochoric process.

The Ideal Otto cycle consists of four internally reversible processes in series.

Adiabatic Process and Isometric occurs.

1→2 isentropic compression or air as the piston moves from BDC to TDC

2→3 constant volume (isometric) heat addition to the fuel/air mixture from an external

source while the piston is at TDC (represents the ignition process and the subsequent

burning of fuel)

3→4 isentropic expansion (power stroke)

4→1 constant volume (isometric) heat rejection at BDC

Ideal otto cycle:

Practical otto cycle:

The Pratical Otto cycle consists of four internally reversible processes in series.

Adiabatic Process and Isometric doesn’t occurs

1→2 isentropic compression or air as the piston moves from BDC to TDC

2→3 constant volume (isometric) heat addition to the fuel/air mixture from an external

source while the piston is at TDC (represents the ignition process and the subsequent

burning of fuel)

3→4 isentropic expansion (power stroke)

4→1 constant volume (isometric) heat rejection at BDC

The Ideal Diesel cycle consists of four internally reversible processes in series.

Adiabatic Process and Isochoric occurs

1→2 adiabatic compression or air as the piston moves from BDC to TDC

2→3 constant pressure (isochoric)

3→4 adiabatic expansion (power stroke)

4→1 constant volume (isometric) exhaust of gases

Ideal diesel cycle:

Practical diesel cycle:

The Practical Diesel cycle consists of four internally reversible processes in series.

Adiabatic Process and Isochoric doesn’t occurs

1→2 air intake

2→3 compression

3→4 combustion with constant pressure

4→5 expansion

5→1 exhaust of gases

Difference betweenotto cycle and diesel cycle

Diesel Cycle

Questions ?