| Group-A | Group-B |
| a. Intake stroke | (i) Air and petrol mixture is ignited |
| b. Compression stroke | (ii) Piston moves away from the spark plug |
| c. Ignition stroke | (iii) Outlet valves open, gases are pushed out |
| d. Expansion stroke | (iv) Piston moves towards the spark plug |
| e. Exhaust stroke | (v) Heat and gases are released |