Normal Combustion - BOMBARDIER 1996 Ski-doo MX Z440 Handbook

Rings
Cylinder
Cylinder head
4. Cylinder head cover
5. Sparkplug
6. Sparkplug
7. Combustion chamber
Exhaust port
8.
COMBUSTION PROCESS

NORMAL COMBUSTION

Since the beginning of this study we have spoken of air/fuel mixture combustion rather than
explosion. This combustion is a slow then accelerated burning of the mixture within the combustion
chamber. Ignition occurs with the firing of the spark plug.
This initial process generates heat and pressure which in turn, is transmitted by conduction to the
contiguous portion of the unburned mixture. When this portion has reached the point of self-
ignition it starts to burn releasing more pressure and heat.
This burning action, called a flame front, travels at a speed of approximately 30.3 m.(100 feet) per
second until all mixture is burned, thus providing maximum piston thrust.
F01D5GS
9. Transfer port
10. Wrist pin
11. Intake port
12. Oil pump
13. Crankcase
14. Crankshaft
15. Connecting rod
16. Piston
Section 04
ENGINE PREPARATION
Spark occurs
as piston
approches Top
Dead Center
04-7