Observation

Only a few candidates attempted this question. The attempt on the question was not good enough. The solution to the question is given below.

(a) The Sketch of Two-stroke Spark Ignition Engine during Its upward Movement with Labelled Parts



(b) Merits of Two-stroke Cycle Engine

The engine:

- is lighter.
- has fewer parts.
- has high running speed.
- has smoother torque as it has one power stroke for every revolution.
- has simple lubrication system.
- is easy to maintain.
- has low initial cost or cheaper.
- is very portable.
- can be used either on small engines stationary machines or on moving machines.

Demerits of Two-stroke Cycle Engine

The engine:

- is easy to get overheated.
- produces high/loud noise.
- has poor lubrication system.
- has inadequate cooling process.
- is limited to only small engine.
- has low load-carrying ability.
- has poor scarvenging.
- has high fuel consumption as some fresh charge escapes with exhaust gas.
- requires frequent decarbonizing