The Small Internal Combustion Engine

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The Small Internal Combustion Engine

• Prepared by
• Eric Johannesen
• Iowa-Grant High School

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Technology in Mechanical Machines

• Technology is much advanced since 1876 when the
  first external combustion steam tractor was
  successfully manufactured.
• Everything is more efficient
• Practical

3
Motors vs. Engines

• Motors
• Motors must be supplied with energy from an
  external power source

• Engines
• Identifies a machine which is able to produce
  power independent from an external power source.

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Internal Combustion Engine vs. External
Combustion Engine

• Internal Combustion Engine
• Capable of converting heat, developed by the
  burning of a fuel within a combustion chamber

• External Combustion Engine
• Steam powered

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Air Cooled vs. Water Cooled

• Air Cooled

• Water Cooled

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Principles of Engine Operation

• Two types of Internal-Combustion engines are in
  present use.
• The Piston Engine
• Sometimes called the reciprocating type engine
  because the piston moves up and down in the
  cylinder in a reciprocating action
• Rotary Engine
• Two Types
• The Turbine Engine used in jet aircraft
• Wankel Engine

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Rotary Engines
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Basic Parts of the Piston Engine

• Cylinder
• Cylinder and housing
• The cylinder or block is usually cast iron or
  aluminum

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Basic Parts of the Piston Engine

• Piston
• Sliding part of the combustion chamber
• It performs the important function of
  transmitting heat energy into straight line
  motion.
• Piston Rings
• Compression, Scrapers, and Oil

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Basic Parts of the Piston Engine

• Connecting Rod
• Transfers the sliding force of the piston to the
  crankshaft.

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Basic Parts of the Piston Engine

• Crankshaft
• The purpose of the crankshaft is to convert the
  reciprocating action of the piston into rotary
  motion and force.
• Crankshafts are manufactured using highly refined
  nodular cast iron.

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Basic Parts of the Piston Engine

• Flywheel
• Attached to one end of the crankshaft.
• The function of the flywheel is to even out power
  flow to the crankshaft by resisting any change in
  speed of rotation
• Small Engine-Helps to cool the engine
• It is usually part of the magneto-ignition system

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Basic Parts of the Piston Engine
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Engine Operation

• Spark Ignition
• A mixture of air is drawn into the combustion
  chamber of the cylinder through the intake valve
  or port
• A mixture is then compressed into a much smaller
  volume
• The compressed gases are ignited at the correct
  position of the piston in the cylinder
• The burning gases then expand, driving the piston
  down with great force.
• During the end of the stroke, the exhaust port or
  valve opens releasing spent gases.

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Engine Operation-Spark Ignition

• The first successful engine to operate in this
  manner was developed by Dr. N.A. Otto in 1876
• The engine required 4-strokes of the piston to
  complete the events in the proper sequence.

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Four-Stroke-Cycle Engine
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Four-Stroke-Cycle Engine

• Intake Stroke
• This is the process of getting the fuel and air
  required for combustion into the combustion
  chamber.
• The exhaust valve is closed and the intake valve
  is open.
• The piston is moving down in the cylinder and the
  fuel air mixture is drawn into the combustion
  chamber.

• Compression Stroke
• The process of compressing the air and fuel
  mixture in the combustion chamber.
• Both valves are closed
• Piston is moving up in the cylinder.
• The spark plug will ignite the mixture as the
  cylinder reached TDC
• The spark causes an explosion forcing the piston
  down in the cylinder

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Four-Stroke-Cycle Engine

• Power Stroke
• This is the result of converting the chemical
  potential energy to mechanical power by the rapid
  expansion of gasses in the cylinder.
• These gasses are produced by the combustion of
  the compressed fuel/air mixture.
• Both valves are closed and the piston is moving
  downward in the cylinder

• Exhaust Stroke
• This is the process of removing the spent
  products resulting from combustion in the
  combustion chamber.
• After the power stroke, the cylinder contains
  burned gasses.
• During the exhaust stroke, the exhaust valve
  opens and the spent gasses are forced out of the
  cylinder.
• Exhaust valve is open and the piston is moving up
  in the cylinder.

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Four-Stroke-Cycle Engine
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Rotary Engines

• Wankel Engine

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Classification of Internal Combustion Piston
Engines

• Internal Combustion Engines can be classified by
  the following manner.
• Four and Two Stroke Engines
• Classified by Power
• Classified by Piston Displacement
• Number of Cylinders
• The manner in which the cylinders are arranged
• Fuel they use

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Number of Cylinders

• Single Cylinder
• These Engines only have one cylinder
• Usually small horsepower engines

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Number of Cylinders

• Multi-Cylinder Engines
• Engines that have 2, 3, 4, 5, 6, 8, 10, or 12
  cylinders

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Cylinder Arrangement

• In-Line Engine
• All Cylinders are in a straight line

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Cylinder Arrangement

• V-Blocks
• Means the engine cylinders are arranged in a V
  configuration with two banks of cylinders on a 90
  degree angle operating off the same drive shaft.

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Cylinder Arrangement

• Slant
• Mopar or Dodge Engines
• Not used in the agricultural industry

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Two-Stroke-Cycle Engine
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Two-Stroke-Cycle Engine
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Engine Operation

• Compression Ignition Engines
• Engines which burn gasoline use an electric spark
  to ignite the air fuel mixture.
• Compression Ignition Engines use the heat
  generated by compression to ignite the fuel
• Diesel Engine
• Most of them are 4 stroke diesel engines
• Intake, Compression, Power, and Exhaust

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Compression Ignition Engines