In the recent years, considerable efforts have been devoted towards improving the performance and emissions of small 4 stroke spark ignition engines by lean burn combustion techniques. However, there are certain drawbacks associated with the lean burn engines which are, large cyclic variations, long combustion duration, unreliable ignition of the mixture in some cycles.
An experimental investigation has been carried out on a 150 cc air cooled four stroke gasoline engine to improve the lean burning limits by overcoming the difficulties associated. The following strategies have been considered for the study.
- 1
Use of catalytic materials in the combustion chamber to accelerate combustion.
- 2
Pre-chamber with catalytic activation.
- 3
Optimization of compression ratio and valve timing to improve flame propagation.
- 4
By using an ignition system with high-energy spark discharge and increased spark duration, to help ignite the lean mixture.
- 5
Combustion chamber optimization.
Basic engine performance data viz, Torque, Power, BSFC, Emissions, Combustion pressure,etc,.have been collected on the test engines with necessary modifications and analysed.