Lotus TURBO ESPRIT Service Manual page 362

Page 4
SECTION LC
LC.1
-
GENERAL
DESCRIPTION
Two fuel tanks are fitted, one ahead of each rear wheelarch.
A
seperate filler neck
with lockable cap is provided for each tunk, and the tvm tunks are interconnected
by a large bore balance pipe.
A
single sender unit for the fuel gauge is fitted into
the top of the right hand fank.
Fuel i s fed from the leff hand tank to a high pressure furbine type fuel pump capable
of delivering
100
litres/hour. Fuel i s then fed through a canister filter also fitted
beneath the left hand front corner of the engine bay, and then to the fuel pressure
regulating valve mounted on the rear of the carburettor plenum chamber.
A
spring and diaphragm system i n the regulating valve i s adjusted to set fuel
2
pressure to
4.0
-
4.5
Ib/in under light load conditions, but as inlet boost
pressure i s developed,
a
sensing pipe from the plenum chamber adds
a
boost
pressure signal to the spring pressure to ensure that fuel pressure i s maintained
2
at
4.0
-
4.5
Ib/in above boost pressure. However, a micro-switch mounted
on the front of the front carburettor and operated by the throttle lever in its
fully closed position energises the fuel pressure solenoid, fitted beneath the
rear of the plenum chamber. The signal to the fuel pressure regulator is then
switched to number one cylinder inlet manifold depression, thus reducing fuel
pressure to the carburettors and mixture strength under closed throttle 'overun'
conditiorrs.
Excess fuel supplied to the regulating valve i s returned via-a port i n the bottom
of the valve to the right hand tank, whilst two sepemte pipes from the valve,
carry fuel to the front and rear carburettors.
LC
.2
-
CARBURETTOR
-
THEORY
OF OPERATION
Carburettor Type
-
Dellorto DHIA
45M (2
off)
Fuel Supply
Fuel from the union (1)
passes
through the filter
(2)
and
reaches the needle valve
seat (18), where fhe needle valve
(li'),
attached to the
float (15),
controls the
fuel flow into the float chamber, thereby maintaining a constunt level
.
The float chamber is vented to the plenum chamber through the hole
(4)
i n the
chamber
(3).