Session 2: Replacement of Piston Rings
Module 2: Serviceability, Replacement or Repair of Engine Components
Textual Question-Answers
Check Your Progress
Fill in the blanks
1. The primary functions of piston rings in an internal combustionengine are to seal ……………. so that there is no transfer of combustion gases from the chamber to the crankcase.
Ans: the combustion chamber
2. The top two rings in most automobile engines are known as……………. while the lower ring is an oil ring responsible for controllingoil supply.
Ans: compression rings
3. Piston rings are subjected to wear due to movement within thecylinder bore as the piston moves from …………… to Bottom DeadCentre.
Ans: Top Dead Centre
4. During the inspection of piston clearance in a multi-cylinderengine, a set of tools including spanners, a micrometer, and a ………….. gauge is used to ensure correct gaps and clearances.
Ans: feeler gauge
Multiple Choice Questions
1. What is the main function of piston rings in an internal combustionengine?
A) To increase fuel efficiency
B) To regulate exhaust emissions
C) To cool down the engine components
D) To seal the combustion chamber and prevent gas leakage
Ans: D) To seal the combustion chamber and prevent gas leakage
2. Which type of piston ring is responsible for controlling the supply of oil to the cylinder liner?
A) Compression ring
B) Exhaust ring
C) Oil ring
D) Power ring
Ans: C) Oil ring
3. What is the primary reason for the wear of piston rings in anengine?
A) Movement within the cylinder bore during engine cycles
B) Inadequate cooling
C) Excessive lubrication
D) Irregular combustion
Ans: A) Movement within the cylinder bore during engine cycles
4. What is the purpose of inspecting the end gap of a piston ring?A) To measure the thickness of the ring
B) To check for wear on the cylinder bore
C) To ensure proper alignment and expansion of the piston ringD) To determine the oil consumption rate of the engine
Ans: C) To ensure proper alignment and expansion of the piston ringAnswer the following questions
1. How many types of rings used in piston?
Ans: Three types of rings are used in a piston, two compression rings andone oil control ring.
2. How much the clearance provided in the cylinder bore?Ans: The clearance provided in the cylinder bore is generally about 0.02mm to 0.06 mm.
3. What are the functions of compression rings?
Ans: The functions of compression rings are to seal the combustionchamber, prevent gas leakage into the crankcase, transfer heat from the pistonto the cylinder wall, and maintain compression pressure.
4. What are the functions of oil control ring?
Ans: The functions of the oil control ring are to control the amount oflubricating oil on the cylinder wall, scrape excess oil back to the crankcase, and prevent oil from entering the combustion chamber.
5. What is the position of the ring in the piston?
Ans: Compression rings are fitted in the upper grooves of the piston andthe oil control ring is fitted in the lowest groove.
Activity
1. Make a list of steps required to measure the clearance betweenpiston and cylinder wall.
Ans:
S. No. Steps
1. Clean the piston and cylinder bore thoroughly
2. Measure the piston diameter using a micrometer
3. Measure the cylinder bore diameter using a bore gauge
4. Calculate the clearance by subtracting piston diameter from borediameter
5. Make a poster showing piston and piston rings and label parts.
Ans:
