
130 LIGHT AND HEAVY VEHICLE TECHNOLOGY
strangler flap in opposition to the closing torque exerted
by a cold thermostat coil. In so doing it is assisted by
the engine depression acting on the unbalanced areas of
the strangler flap. The latter is therefore forced to open
a predetermined amount to maintain the engine running
once it has started. Further movement of the vacuum-
kick piston then closes off the depression port, so that
the movement of the strangler flap will be governed
solely by the thermostat coil. If the engine depression
is reduced, as a result of an increased load or sud-
den acceleration, the return motion of the vacuum-
kick