In Internal Combustion (I.C.) engines, seat inserts and valves are the major components responsible for performance, emissions and reliability. Failure of these components can cause performance deterioration. In case of compressed natural gas (CNG) engines, impact on life of seat inserts and valves are adversely affected due to its dry combustion environment and high operating temperatures.
Greaves cotton has developed a single cylinder, water cooled, dedicated CNG engine with port injection from the base diesel engine. Major challenges were encountered during the CNG engine development with respect to seat inserts and valves wear. The design was modified considering the different design parameters to arrest failure modes as given below:
- 1
Seat insert material compatibility
- 2
Seat angle
- 3
Seat width
- 4
Valve head stiffness
- 5
Alignment of seat inserts and valves
- 6
Valves closing velocities.
Valves & seat inserts wear could be successfully resolved by design modifications and the same was validated through engine bed & vehicle level testing.