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Flashcards in 190201d Deck (22)
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1
Q

The main 4 components of a piston and connecting rod assembly are:

A
  • Piston
  • Piston Rings
  • Piston Pin
  • Connecting Rod
2
Q

What TEMPERATURE and PRESSURE does a piston encounter in a running diesel engine?

A

Pressure - 2000psi (13789.5kPa…though current pressures are near 3k-4k)

Temperature - 3500F

3
Q

Why is aluminum used for the construction of diesel engine pistons?

A

Aluminum is:

  • lighter
  • produces less engine vibrations
  • 3x the heat conductivity of cast iron
  • provides a bearing surface for piston pins
4
Q

What is the main characteristic of a TRUNK TYPE piston?

A

The crown and skirt are manufactured as one piece

5
Q

What are 5 main parts of a piston?

A
  • Valve reliefs
  • Crown
  • Skirt
  • Piston pin bore
  • Piston ring grooves
  • Dome
  • Ring lands
  • Oil holes
6
Q

The purpose of CAM GRINDING the skirt of a one-piece aluminum piston is to:

A

Allow the uneven expansion in the piston pin bore area

7
Q

In a piston, what purpose do the holes in the oil ring groove serve?

A

To allow oil to freely move when lubricating the cylinder wall.

8
Q

Ring groove inserts are used in aluminum piston construction to:

A

Reduce wear in and reinforce compression ring grooves

9
Q

What is the purpose of the slipper skirt piston design?

A

To provide clearance between the slipper skirt and crankshaft, when the piston is at BDC

10
Q

What is the advantage of using a two-piece piston design?

A
  • The piston head/crown is made of strong material to withstand high heat and pressure
  • Combustion forces are transferred directly from the crown a bushing a piston pin assembly
  • Piston crown motion is reduced
  • Direct loading and a greater pin bushing area reduce bending stress on the piston
11
Q

What is a semi-floating piston pin?

A

A pin that freely rotates in the piston, but is fixed to the connecting rod

12
Q

What is the most common type of piston cooling used in a medium/high-speed diesel engine?

A

Oil sprayed through a piston cooling nozzle

13
Q

What are the two types of piston rings used in an engine?

A
  • Compression rings

- Oil control rings

14
Q

The purpose of piston ring end gap is:

A

to allow clearance for ring expansion (from heat)

15
Q

What 3 factors help a compression ring create an effective seal along the cylinder wall?

A
  • Oil film
  • Ring tension
  • Cylinder pressure
16
Q

The purpose of an oil ring expander is to:

A

Provide the needed ring tension for oil control

17
Q

The two main advantages of a KEYSTONE ring over a RECTANGULAR ring are:

A
  • Stronger ring lands due to the tapered groove

- Self cleaning (greater resistance to buildup)

18
Q

Chromium plating is used on compression rings because:

A

It increases heat transfer and reduces friction

19
Q

What is the purpose of a connecting rod?

A

It forms a link to transfer combustion force from the piston to the crankshaft

20
Q

Identify 5 parts of a connecting rod:

A
  • Nut
  • Balance pad
  • Thrust face
  • Rod bearing bore
  • Parting line
  • Beam shank
  • Piston pin bushing
  • Piston pin bore
  • Bolt
21
Q

What are four methods of maintaining connecting rod and cap alignment?

A
  • Fracturing
  • Dowel pins
  • External markings
  • Shouldered bolt
  • Tongue and groove joint
  • Serrated joint
22
Q

Identify two connecting rod designs:

A
  • Straight cut
  • Bias cut
  • Fork and blade
  • Articulated