KEEWAY ARN125, Service And Maintenance Manual

Page: 8 / 85

8
2
．
． ．
．
4-STROKE ENGINE CYCLE
A
：
： ：
：
INLET STROKE
1
、
CRANKSHAFT TURNS ANTICLOCKWISE.
2
、
CRANKSHAFT BRINGS ALONG PISTON TO MOVE THROUGH CONNECTING ROD.
3
、
WHEN PISTON TRAVES FROM TOP DEAD CENTER TO BOTTOM DEAD CENTER, INLET
PORT OPENS, MIXED GAS GOES INTO CYLINDER.
B. COMPRESSION STROKE
1. CRANKSHAFT REVOLVES CONTINUALLY, BRING ALONG THE PISTON TO MOVE FROM
TOP DEAD CENTER TO BOTTOM DEAD CENTER THROUGH CONNECTING ROD.
2. MIXTURE AIR IS COMPRESSED INTO A NARROW SPACE BETWEEN CYLINDER HEAD
AND PISTON HEAD, WHICH IS CALLED BURNING CHAMBER.
C CC C： ： ： ： POWER STROKE POWER STROKE POWER STROKE POWER STROKE
1. SPARK PLUG INNITES COMPRESSED MIXED GAS OF AIR AND FUEL.
2. Burning of mixed gas of air and fuel results in sudden change of temperature
and pressure in Burning chamber, and then burning gas expands, the power acted on piston
push piston to move down. The power acted on piston transfers to crankshaft through
connecting rod, which leads that crankshaft moves more fastly. Expansion of burning mixed
gas provides enough power.
D: EXHAUST STROKE D: EXHAUST STROKE D: EXHAUST STROKE D: EXHAUST STROKE
b) When burning gas pushes piston continually to bottom, exhaust port opens.
c) For inertia crankshaft push piston to Move toward cyliner head.
d)
As piston moves toward cylinder head, burning gas is excelled from exhaust port. When piston
travels to top end,
exhaust port is shut off.