JAGUARS-TYPEFuel System
38
Introduction
The fuel tank components, operation and layout
are new to Jaguar and have no commonality with
previous systems. The major features of the fuel
delivery system are the use of a saddle type tank
and a returnless fuel system. The evaporative loss
management system is similar in operation to that
fitted to the XJ and XK Series vehicles and on-
board refuelling vapour recovery (ORVR) is a
standard feature. For NAS markets only, leak test
diagnostics are performed.
Returnless Fuel System
The returnless fuel system delivers the correct
amount of fuel to the engine under all conditions
and at a constant pressure differential with
respect to manifold pressure. This is without the
need for a return line to the tank or a fuel rail
pressure regulator. The use of a return line and
the pressure drop across a regulator contribute to
vapour formation which can affect fuelling
calibration and requires a complex vapour
management system to meet legislative
requirements. Elimination of these components,
D.310.047
together with closed loop control of the variable
speed fuel pump, causes a reduction in the vapour
generated, lower fuel temperatures and better fuel
pressure control. Additional advantages include a
reduced load on the electrical system and
improved fuel economy.
Fuel Tank
The fuel tank is of the ÔsaddleÕ type shape with LH
and RH fuel compartments and is constructed of
high density polyethylene (HDPE), a plastic blow
moulded material. The tank is located below the
rear passenger seat with the drive shaft and
exhaust running through the arch of the tank. The
underside of the tank is protected by a fitted heat
shield and the tank assembly is retained by two
metal straps which are fixed to the underbody at
the front by removeable hinge pins and at the rear
by bolts.
Refuelling is via a separate filler pipe and
connecting hose to a stub pipe on the RH fuel
compartment.
A fuel pump module is located in the RH
UNDERFLOOR FUEL TANK AND CARBON CAN SYSTEM LAYOUT
Carbon Can AssemblyFuel Filler (pipe removed)
Fuel Tank Assembly
JAGUARS-TYPEFuel System
42
Evaporative Emissions System
The function and operation of the on-board
refueling vapor recovery (ORVR) evaporative
emissions system are similar to the system fitted
to the XJ and XK Series vehicles in NAS markets
but use different components. For the S-TYPE the
system is fitted as standard for all markets.
Fuel Tank Components
To meet ORVR evaporative emission
requirements, the tank and associated
components are designed to minimise vapour
losses. During re-fuelling, the narrowed fuel filler
tube below the nozzle region provides a liquidseal against the escape of vapour and a check
valve in the tank inlet pipe opens to incoming fuel
only to prevent splashback. As the tank fills,
vapour escapes through the open float level vent
valve, at the top of the tank, and passes through
the adsorption canisters to atmosphere. When the
rising fuel level closes the float valve, the resulting
back pressure causes refuelling cut-off. While the
float valve is closed, any further rise in vapour
pressure is relieved by the grade vent valve which
connects to the canisters via the outlet of the float
valve. At less than full tank level, the float valve is
always open, providing an unrestricted vapour
outlet to the canisters.
If the tank is over filled (eg a fault in the delivery
system) an integral pressure relief valve in the float
valve assembly opens to provide a direct vent to
atmosphere.
The float level vent valve/pressure relief valve
assembly and the grade valve are welded to the
tank top and are non-serviceable. Note that both
valve assemblies incorporate roll-over protection.
The fuel filler cap uses a 1/8 turn action and is
tethered to the body. The filler cap assembly
incorporates both pressure relief and vacuum
relief valves (the latter is a new feature to Jaguar).
D.310.049
FUEL TANK CONNECTIONS
Fuel Tank
Pressure Valve
(NAS markets only)
Jet Pump Assembly
Connectors
Fuel Pump
Connectors
To Carbon
Canister
Vapour to EVAP Valve
Fuel to Engine
Fuel Transfer
Pipes
