Engines Essay

This essay has a total of 866 words and 5 pages.

Engines



Engines



Engines are found all around our very day lives. They are found in our cars, trucks, vans
and motorcycles. Almost all vehicles run on the basic combustion engine. An internal-
combustion engine is any type of machine that gets mechanical energy from the expenditure
of the chemical energy of fuel burned in a combustion chamber. There are four main types
of internal- combustion engines, they are: the Otto - cycle engine, the diesel engine, the
rotary engine and the gas turbine. The Otto-cycle engine is usually used in gasoline
engines found in cars and airplanes. The diesel engine runs on a different principle and
mainly uses oil as fuel. It is used in electric-generating and marine-power plants, in
trucks, buses and some cars. Both diesel and Otto-cycle engines are made in two-stroke
and four-stroke cycle models.


The first piston engine was developed in 1690 by a French physicist and inventor Denis
Papin and it was used for pumping water. His first engine was a crude machine that used
air. It was a single cylindered engine that also was used as a boiler. There was a small
amount of water placed in the bottom of the cylinder and it was heated until steam was
formed. The pressure that was made from the steam made the piston rise fitting in the
cylinder, and after it was raised the heat was removed from the bottom of the cylinder.
As the cylinder cooled, the steam condensed and the air pressure on the top of the piston
pushed the piston down.


The main parts of an Otto-cycle engine and a diesel engine are the same. Their combustion
chamber has cylinders that are closed at one end and in which a close-fitting piston
slides. The outside of the piston is connected to a crankshaft by a connecting rod. The
crankshaft changes the motion of the pistons in a rotary motion. Crankshafts have heavy
flywheels and counterweights hooked on to them to keep the motion of the shaft smooth. An
engine can have from 1 cylinder to 28 cylinders.


In every engine there is some sort of fuel system. If not the engine wouldn't run.
Vehicles have a gas tank, a fuel pump and a carburetor. Newer cars have a fuel injection
system. In most engines with a carburetor, the fuel is sent to the cylinders through a
branched pipe called the intake manifold. The fuel is sent to each cylinder and the
wasted gases exhausted through mechanically operated poppet valves or sleeve valves. The
valves are normally kept shut by the pressure of the springs and are opened at the right
time during the operation cycle of the cam on a rotating camshaft that is geared to the
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