Question 3
(a) The sketch in Fig. 2 shows a dry liner used on automobile engine.
i. Explain why the liner is called dry liner.
ii. Name the parts labelled; E, F, G, H\
(b) State three differences between a dry liner and a wet liner, as applied to automobile engines.
(c) What is the main purpose for cooling automobile engines?
Observation
The attempts on the question were not good enough. Most candidates who attempted (c) part of the question got it right. The solution to the part of the question not gotten correctly is given below.
(a) (i) It is called dry liner because the coolant does not have direct contact with the lining or because the cylinder liner is not in direct contact with the coolant (water)
(ii) E: Cylinder bore, engine bore or bore
F: Cylinder block or Engine block or block
G: Water or Coolant or water jacket
H: Cylinder lining, liner, lining, cylinder sleeve or sleeve
(b)
Dry Liner |
Wet Liner |
- Coolant does not have contact with the liner |
- Coolant has direct contact with liner cooling |
- Coolant leakage is eliminated |
- Leakage of coolant is possible |
- The liner has interference fit |
- Liner is easily fitted or lining has push-fit |
- There is less efficient cooling |
- There is more efficient cooling |
- Worn-out block can only be rebored - It requires a reboring machine |
- New liner can easily be fitted into the block |
- It has thinner section |
- It has thicker section |
- It does not require seal |
- Worn-out liner can easily be replaced |