Cylinder head

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Chapter - 3

• Cylinder head
• Cylinder
• Cylinder liner
• Water Jacket
• Cylinder Block-Production
• Cylinder flanges studs
• Design Numerical

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Cylinder Heads

• Separate
• Integral
• Fig. Cylinder with integral head

3
Gaskets

• Copper-Asbestos Gaskets
• Steel-Encased and Other Gaskets

4
Cylinder-Head Studs

• To obtain a gas-tight permanent joint
• With L-head cylinders
• from 16 to 20 studs for a four-cylinder block
• from 24 to 26 for a six-cylinder and
• from 30 to 32for an eight-cylinder
• With , valve-in-head cylinders
• only two rows of studs are required, instead of
  three, and the total number therefore is less

5
Cylinder Material.

• Automobile-engine cylinders generally cast of
  close-grained gray iron approximating the
  following composition.
• Silicon 1.9 to 2.2
• Sulphur not over 0.12
• Phosphorus not over 0.15
• Manganese 0.6 to 0.9
• Combined carbon 0.35 to 0.55
• Total carbon 3.2 to 3.4

6
Heat Cracks in Cylinder Walls

• Cracks - start at the sharp edge formed by the
  cylinder bore and the valve-passage wall.
• May start also at either the inlet/exhaust-valve
  seat
• reaches a very high temperature as hot gases
  pass over it during the exhaust period
• Usually are the result of - pre-ignition - local
  overheating of the combustion-chamber wall
  cooling of overheated metal
• Prevention - Rounding off edge

7
Cylinder Wear.

• Abrasion - due to foreign particles in the oil
  film
• Erosion - due to metal-to-metal contact
• Corrosion - due to chemical action
• The order of importance of the three causes
  varies with conditions of operation.

8
Water Jacket

• Half length full length jacket!
• Jacket wall generally is made as thin as the
  foundry process permits.
• Average practice with regard to jacket-wall
  thickness is as follows
• Cylinder bore, inches 3 4 5 6
• Thickness of jacket wall 5/32 3/16 7/32 1/4

9
Removable Liners

• "Wet" cylinder liner with packing rings
• A "wet" liner is one which is supported by the
  block over narrow belts only, and is surrounded
  by cooling water between these belts

10
Removable Liners

• "Dry" cylinder liner in position
• A "dry" liner is one which is in contact with
  metal of the block over its whole length, or
  nearly its whole length

11
Materials for Cylinder Liners

• Material - nickel-chromium iron - composition
• Total carbon 3.10-3.40
• Combined carbon 0.75-0.90
• Manganese 0.55-0.75
• Phosphorus 0.20 max.
• Sulphur 0.10 max.
• Silicon 1.90-2.10
• Nickel 1.80-2.20
• Chromium 0.55-0.75

12
Production of Engine Blocks

• Cylinders must be molded with the head downward,
  for the reason that blowholes, porous spots, etc.
  are most likely to occur near the top of the
  casting, the head of the cylinder, which is the
  working end, must of necessity be of sound metal.
• When the castings have cooled the core sand is
  removed, the seams etc., are chipped off, the
  castings are then put through a cleaning process.
  Either by pickling neutralizing or by blast
  cleaning (blast cleaning by sand or small
  granules of chilled iron or steel) then
  normalizing cleaning

13
Production of Engine Blocks

• Further the cast cleaned blocks would undergo
  other operations in sequence like Milling,
  Drilling, Cylinder boring, Precision boring,
  Finish of bore, Honing, Lapping, followed by
  measurement of quality of surface finish, Water
  test, Finishing of valve seats guides surface
  broaching.
• Transfer machines were adopted since world war-II
  to perform the operations automatically.

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DESIGN
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Example 1
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Example 1
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Example 2
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Example 3
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Example 3
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Example 3