AUTOMOTIVE ENGINES
GASOLINE ENGINE:
Nikolaus Otto(born 10 June 1832 , in Holzhausen, Germany– died 26 January 1891),who invented 4-Stroke combustion cycle to convert gasoline chemical energy into mechanical energy i.e. into motion in 1867.The 4-Stroke approach is also called as the Otto cycle. The 4-strokes are as follows:
- Intake stroke
- Compression stroke
- Power stroke
- Exhaust stroke
1 Intake stroke: The piston starts at the top, the intake valve opens, and the piston moves down so that the engine takes in a cylinder full of air and gasoline.
2 Compression stroke: Then the piston moves back up to compress this fuel and air mixture. Compression makes s the explosion more powerful.
3 Power stroke: When the piston reaches the top of its compression stroke, the spark plug emits a spark to ignite the petrol. The gasoline charge in the cylinder explodes ,the pressure of the hot gases push the piston down, delivering power to the crank-shaft and fly wheel.
4 Exhaust stroke: . The exhaust valve opens and the rising piston pushes the burnt gases out of the cylinder. When the piston gets near the top the exhaust valve closes and the inlet valve opens, now the engine is ready for the next cycle, so it intakes another charge of air and gasoline.
DIESEL ENGINE
Rudolf Christian Karl Diesel (born March 18, 1858 in Paris– died September 29, 1913), a thermal engineer who invented the internal-combustion engine that bears his name. He obtained a German development patent in 1892 and the following year published a description of his engine under the title (Theory and Construction of a Rational Heat Motor).He produced a series of increasingly successful models, culminating in his demonstration in 1897 of a 25-horsepower, four-stroke, single vertical cylinder compression engine. The high efficiency of Diesel’s engine, together with its comparative simplicity of design, made it an immediate commercial success.
The main difference between the Gasoline and Diesel engine is the burning of the fuel.
In a Gasoline engine, the air/fuel mixture enters the cylinder and creates a stoichiometric homogeneous
mixture, the spark plug emits a spark to ignite the gasoline.
In the Diesel engine, there is no spark plug .Air enters the cylinder, diesel fuel is injected. Compression stroke creates high temperature and pressure causes fuel to ignite.
Diesel fuel has a higher energy density than gasoline, so a diesel engine gets better mileage.
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