1. The four-stroke engine
Spark plug
Exhaust valve
Inlet valve
Cylinder
Piston

2. The four-stroke engine
Inlet valve
open
INDUCTION STROKE

3. The four-stroke engine
Inlet valve
open
INDUCTION STROKE
Piston down

4. The four-stroke engine
Fuel in
Inlet valve
open
INDUCTION STROKE
Piston down

5. The four-stroke engine
Fuel in
Inlet valve
open
INDUCTION STROKE
Piston down

6. The four-stroke engine
Fuel in
Inlet valve
open
INDUCTION STROKE

7. The four-stroke engine
Inlet valve
closed
Piston up
COMPRESSION STROKE

8. The four-stroke engine
Inlet valve
closed
Piston up
COMPRESSION STROKE

9. The four-stroke engine
Inlet valve
closed
Piston up
COMPRESSION STROKE

10. The four-stroke engine
Inlet valve
closed
BANG
POWER STROKE

11. The four-stroke engine
Inlet valve
closed
Piston down
powerfully
POWER STROKE

12. The four-stroke engine
Inlet valve
closed
POWER STROKE
Piston down
powerfully

13. The four-stroke engine
Inlet valve
closed
POWER STROKE

14. The four-stroke engine
Inlet valve
closed
Exhaust valve
open
EXHAUST STROKE

15. The four-stroke engine
Inlet valve
closed
Exhaust valve
open
Exhaust gases
out
Piston up
EXHAUST STROKE

16. The four-stroke engine
Inlet valve
closed
Exhaust valve
open
Exhaust gases
out
Piston up
EXHAUST STROKE

17. The four-stroke engine
Inlet valve
open
Exhaust valve
closed
INDUCTION STROKE

18. And so the
cycle
continues!!