The Action of a Common Slide Valve

The action of a common slide valve may be traced as follows:

Port a, open to the amount of the lead.

Port a, full open for the admission.

Port a, closed off for cut.

Valve opening port a, for the exhaust.

Port a, full open for the exhaust.

Suppose the port a to be at the head end of the cylinder and open to the amount of the lead with the crank on the corresponding dead centre, and if the valve travel be made equal to twice the lap and the lead, the various positions of the valve will be as marked in Figs. from 3298 to 3302; the event corresponding to each valve position being stated in the figures.