Lotus Elise Service Notes page 547

Lotus Service Notes
340 H
The sequence of operation is as follows:
a). Normal running - Both solenoid
valves off - Flap valve open
The flap capsule is vented to at-
mosphere, and the flap valve is sprung
open.
Inlet manifold sealed by the lock-
ing capsule.
b). Cruising at 30 mph in second or
third gear - Charging solenoid on - Flap
valve closed
Charging solenoid is energised.
Flap capsule is connected to mani-
fold vacuum - flap valve is closed.
Vacuum
locking
solenoid
OFF
Locking
solenoid
OFF
Vacuum
charging
solenoid
OFF
Manifold
vacuum
To flap
capsule
Charging solenoid
ON
vacuum To flap
capsule
c). Cruising or accelerating at 30 mph
in second or third gear - Both solenoids
on - Flap valve closed
Within two seconds of condition
(b) occuring, the vacuum locking sole-
noid is also energised and seals the
vacuum in the flap capsule. This is
necessary in order to prevent loss of
manifold vacuum during wide throttle
acceleration resulting in insufficient
vacuum at the flap capsule to maintain
flap closure.
When the conditions required for
intake resonance suppression no longer
apply, both solenoid valves are de-en-
ergised and the flap valve is opened.
Locking
solenoid
ON
Charging solenoid
ON
Manifold
vacuum To flap
capsule
lem21SI
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