Diagram 1 shows the inlet port opening and the exhaust port
closing at the beginning of the suction stroke. The inner sleeve
is rising and the outer sleeve is descending
Diagram 2 shows the exhaust closed and the inlet closing at the
beginning of the compression stroke. The ports in the inner
sleeve into the cylinder head, where they are sealed by the junk
ring during the period of maximum pressure and temperature at the
beginning of the firing stroke (see Diagram 3).
Diagram 4 shows the exhaust already well opened at the beginning
of the exhaust stroke, The sleeves are now again moving to the
position shown in Diagram 1.
The complete cycle of operations - suction, compression firing
and exhaust - occupies two revolutions of the crankshaft.