Chery SQR 7160 sedan. Manual - part 44

CAC Gasoline Engine Maintenance And Servicing Manual

1. fuel tank 2. Two-way check valve 3. fuel Injection pressure system

4.multi-function valve 6. charcoal canister

7. fuel vapor recirculation solenoid 8.throttle valve body

        After long time since engine stopped, the temperature in the fuel tank will rise (Since the vehicle doesn’t
move, the dynamic ventilation is not enough.) and the pressure in the fuel tank will rise.
        —— When the fuel tank is full, the  multi-function  valve 4 is closed.  The fuel cannot flow into charcoal
canister 6, therefore it doesn’t damage charcoal canister.

Fig. 154 principle drawing of anti-fuel vaporization system

Ignition switch

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CAC Gasoline Engine Maintenance And Servicing Manual

If the pressure in the fuel tank (1) rises beyond the specified value, two-way check valve (2) will open

reducing the pressure in the fuel tank.
        If necessary, the valve may open reversely to vent inward when the fuel tank is vacuumed.
        —When the fuel level is at middle or low , when it exceeds a specified pressure, the multi-function valve
(4)  will  permit  the  fuel  vapor  to  reach  the  charcoal  canister  (6)  and  be  absorbed  by  the  activated  carbon
granule.
        The operation when engine is running (figure. 155)。
        Solenoid (7) is powered on by ignition switch and is controlled by the injection system ECU  directly by
the  following  modes:  When  the  valve  is  open,  the  vacuum  in  engine  will  suck  the  vapor  collections  in  the
charcoal canister into the lower part of throttle valve. When powered off, the valve will close to prevent theλ
sensor from sucking the vapor when it doesn’t work.

8    fuel vapor recirculation solenoid valve (condensing chamber EC1)
      the  fuel  vapor  recirculation  solenoid  valve  is  designed  to  regulate  the  vapor  volume(from  the

charcoal

canister

) controlled by ECU. When the solenoid valve is

deenergize

d ,the valve closes.

Its operation is controlled by ECU as following:

·Under the starting condition , the solenoid keeps close

preventing the fuel vapor from richening the mixture until the
specified engine coolant temperature is reached.

·during engine’s running, ECU sends a square wave signal to

the  solenoid.  The  signal  is  used  to  control  the  fuel  vapor
recirculation  valve  by  energizing  or  deenergizing  it.  By  this  way,
ECU controls the fuel vapor volume to intake manifold preventing
the mixture density from changing dramatically.

·under a specified working condition：

—— the throttle

valve is at idling position

—— speed is

lower than the specified

—— the solenoid does not function When the intake pipe

pressure is lower/ higher than the specified value, the solenoid

remains close to improve the engine performance.

—— fuel cut-off switch

the switch is located in the right side of driver. It will cut
off the fuel supply for the injection system by switching off
the ground wire for fuel pump..

Fig.155 solenoid

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CAC Gasoline Engine Maintenance And Servicing Manual

1.fuel tank 2.fuel pump (submerged in fuel tank) 3. Filter screen prefilter (installed in the

inlet of fuel pump)

4.fuel filter                        5.fuel delivery pipe          6.fuel injector(installed in the throttle valve)
7.pressure regulator          8.fuel return pipe
9.fuel recirculation check valve (stop backflowing )          10.fuel cut-off switch

working principle：
        The steel ball ,which is installed in the cone seat, is generally locked by the neighboring magnet attraction.
Under  the  specified  accelerating  load,  the  steel  ball  is  released  from  the  magnetism  stillness  and  begins  to
move up    the cone seat with the travel of the movement depending on the cone angle .
        a  quick-release  mechanism  exists  on  the  top  of  the  ball.  the  mechanism  circuit  is  closed    under  the
normal condition, . When the mechanism is stricken by the ball resulting in the position variation, it will vary
from  the  closed  circuit(NC)  to  the  opened  circuit(NO)  and  cut  off  the  ground  wire  of  fuel  pump
simultaneously.
      For  the  impact  from  any  direction  of  the  three  vertical  directions,  the  switch  will  fuction  under  the
condition of more than the peak value: 12g which is equivalent to the working condition of 25km/h or so.
        The  switch  may  be  reset  by  pressing  the  reset  button.  The  reset  button  is  protected  by  a  flexible  cover
(protecting the button from the influence from the external material and from the necessity of resetting ).
        Warning: Touching the surface lightly. If fuel is smelt or fuel system leaking is present, do not turn on the
switch. The leaking area should be located first and recovered avoiding firing.
        if leaking does not exist on the surface, it may be restarted. Press the button to restart the fuel pump.

Fig.156

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