Combustion

spark plug

In spark ignition engine, the combustion of the air fuel mixture is initiated by a

Nicolas A. Otto

Developed the gasoline engine

self ignition temperature

In compression engine, the combustion of the air fuel mixture is self ignited as a result of compressing the mixture above its

lowest position(BDC)

Initially, both the intake and exhaust valves are closed and the piston is at its

diesel cycle

Is a compression-ignition type of engine

Otto Cycle

Is a spark ignition type of engine

combustion chamber

Most supercharged of turbocharged engines use fuel injection of gasoline directly to

Isentropic Process

Otto Cycle has two constant volume process and two

gas cycles

Spark-Ignition automotive engines, diesel engines, and the conventional gas turbines are devices which operates on . They are also internal combustion engines.

Bore

The Diameter of the piston

Compression Ratio

The efficiency of the otto cycle is dependent only on the

scavenging

The exhaust stroke of the gasoline engine is also known as

Volume process

The heat added in Otto Cycle is during constant

compression ratio of the engine and the specific heat ratio of the working fluid

The thermal efficiency of an ideal otto cycle depends on the

displacement volume

The volume displaced by the piston as it moves between TDC and BDC

volume displacement of the engine

The work output per cycle also depends strongly on the compression ratio as well as the

8.0

Typical compression ratio of otto cycle is

increases

Using monatomic gas, (Helium and Argon) the thermal efficiency of Otto cycle

Reciprocating engines

are classified as a spark-ignition engines or compression ignition engines

Reciprocating engine

basically a piston-cylinder device

Supercharging

blank the engine in otto cycle can increase the power of the cycle but not to increase the efficiency

Rudolf Diesel

developed the diesel engine

constant volume process

diesel cycle has two isentropic, one constant pressure and one

upward

during compression stroke, the piston move , compressing the air fuel mixture

increase

if the specific heat ratio increases, the cycle efficiency will also

increase the efficiency of the engine

increasing the piston diameter or piston stroke of Otto cycle engine will

heat

is added during the constant pressure process

BDC(Bottom Dead Center)

is the position of the piston when it forms the largest volume in the cylinder

TDC(Top Dead Center)

is the position of the piston when it forms the smallest volume in the cylinder

turbocharging

is used in aircraft engines and some automotive engines. In this method, a turbine driven by the exhaust gases is used to provide power to the compressor or blower at the inlet.

engine knock

produces an audible noise

increasing the pressure and temperature

shortly before the piston reaches the highest position, the spark plug fires, of the system

intake valves

the air or air fuel mixture is drawn into the cylinder through the

exhaust valves

the combustion products are expelled from the cylinder through the

stroke of the engine

the distance between the TDC and BDC in which the piston can travel

increasing the pressure ratio

the mean effective pressure of the otto cycle can be increased by increasing the heat transfer into the engine per cycle or by

clearance volume

the minimum volume formed in the cylinder when the piston is at TDC is called

Four-stroke Internal Combustion Engine

the piston executes the complete stroke(two mechanical cycles) within the cylinder, and crankshafts completes two revolutions for each thermodynamic cycles

Autoignition

the premature ignition of the fuel is called

Slightly Above

the pressure in the cylinder is, during the exhaust stroke and slightly below during the intake stroke.

compression ratio

the ratio of the maximum to minimum volume in the cylinder of an internal combustion engine.

specific heat ratio

the second parameter affecting the thermal efficiency of an ideal otto cycle is

25-35 percent

the thermal efficiency of actual spark-ignition engines ranges from about

compression ratio

the thermal efficiency of the car engines has been decreased somewhat as a result of decreased

increases

the thermal efficiency of the otto cycle increases as the compression ratio

4 stroke cycle

the useful output is done during the expansion or compression stroke

less efficient

two stroke engines are generally than four stroke engines because of isentropic expulsion of the exhaust gases and partial expulsion of fresh air fuel mixture and the exhaust gases

simple and inexpensive

two stroke engines are relatively and have high power to weight and power to volume ratios which make them suitable for applications requiring small sizes and weight such as for motorcycles chain saws and lawn mowers

more power

two stroke engines has compared to four stroke engines

two revolutions only

two stroke engines performs intake, compression, and expansion and exhaust srroke in