Overhead Cam 4 Cylinder Internal Combustion Engine

1
Overhead Cam 4 Cylinder Internal Combustion Engine

• MAE 388
• 12/13/05
• Joel Mermoud
• Ted Young
• June Pak
• Babarinde Makanjuola

2
Rotating Assembly
3
General Functions of the Rotating Assembly
Components

• The upper and lower blocks house the rotating
  assembly and create the foundation for the
  engine.
• Rotation of the crankshaft forces the piston and
  connecting rod assembly to move up and down in
  the cylinders of the engine block. The upward and
  downward motion of the pistons create compression
  and vacuum within the cylinders, respectively.

4
Cylinder Head Assembly
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General Functions of the Cylinder Head Assembly
Components

• The cylinder head casting creates the foundation
  for the cylinder head assembly.
• Within the casting are the intake and exhaust
  ports, the valve guides and the combustion
  chambers.
• A cylindrical surface is created by the
  combination of the cylinder head and the rocker
  block, in which the cam shaft is free to rotate.
• The rocker arms rotate about a rocker shaft that
  is secured to the top of the rocker block. The
  rotation of the rocker arms are constrained by
  the geometry of the cam lobes.
• Rotation of the camshaft causes the rocker arms
  to move the valves up and down. The opening of
  the intake valve permits flow of an air/fuel
  mixture through the intake port into the
  cylinder. The closing of both valves allows this
  air/fuel mixture to be compressed. The opening
  of the exhaust valve allows expulsion of the
  exhaust through the exhaust port.

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Operation

• Each cylinder experiences four cycles for every
  two rotations of the crankshaft
• Intake, Compression, Power, and Exhaust
• Explosion of the air/fuel mixture during the
  power stroke provides the energy required to run
  the engine and perpetuate this cyclic process
• These events are timed so that the cylinders fire
  in succession

7

• This project was based on a scale model which
  came with an electric motor assembly to run the
  engine.
• Attached to the rear of the engine, its driven
  gear engages the flywheel and rotates the engine.