2.3.2 Description and Operation
2.3.2.1 Description and Operation

The fuel supply system provides a suitable amount of fuel to
the  engine  in  a  variety  of  operating  conditions.  The  fuel  is
sprayed into the engine through the fuel injectors. Fuel tank
stores fuel. An electric fuel pump is installed in the fuel tank and
it will pump fuel into the fuel rail assembly. Fuel pump provided
fuel pressure exceeds the pressure needed by fuel injectors.
Fuel  pressure  regulator  is  part  of  the  fuel  pump  assembly,
which keeps fuel supplied to the fuel injectors is under specified
pressure. This vehicle fuel system has no fuel return system.

1. Fuel Tank

Fuel tank is made from high-density polypropylene vinyl and
other materials. The fuel tank is tightened by the two connected
metal support brackets at the underbody. and it has a fuel vapor
ventilation valve with roll-over protection function.

2. Fuel Tank Filling Cap

Note

In the need for replacing the fuel tank filler cap, use a fuel
tank filler cap with the same function as the original one.
If the fuel tank filler cap is not correctly installed, it could
cause serious fuel system faults.

The fuel tank filling tube filler cover is equipped with a screw
thread structure, which allows air coming in once it is turned
loose. It uses the structure of the ratchet in order to prevent
over-tightening.  Ventilation  function  means  the  fuel  tank
internal pressure can be released before remove the cap from
the vehicle. Instructions are attached to the cap. The filler cap
also integrates a security vacuum pressure limiting valve.

3. Fuel Pump

Electric fuel pump is a modular fuel turbo pump located inside
the  fuel  tank.  Electric  fuel  pump  is  controlled  by  the  engine
control module (ECM) through the fuel pump relay. Electric fuel
pump will start providing fuel 2s in advance to ensure that the
fuel pressure achieve the requirements of the normal system
operation. The fuel pump resistance range is 0.2-3.0 Ω. This
model comes with electric fuel pump fuel storage in order to
prevent the fuel level too low or provide fuel supply in harsh
operating conditions.

4. Fuel Pressure Regulator

Fuel  pressure  regulator  is  integrated  in  the  fuel  pump
assembly. Fuel pressure regulator main function is to regulate

the fuel pipe fuel flow and to control the fuel injectors pressure.
When the ignition switch is at ON position and the engine is
shut down, the system fuel pressure should be about 400 kPa.

5. Electric Fuel Pump Filter

As a coarse filter, the filter has the following features:

–

Filters the pollutants.

–

Improves the electric pump service life.

If the pump output pressure is found too low, clean or replace
the filter.

6. Fuel Filter Assembly

Fuel Filter Assembly is located in front of the rear suspension,
fixed on the vehicle chassis. Filter consists of a paper filter. It
can filter out the particles that may damage the fuel system.
Fuel  filter  can  withstand  maximum  fuel  system  pressure,
temperature changes and fuel additive effect.

7. Fuel Level Sensor

Fuel  level  sensor  consists  of  a  fuel  level  float,  a  wire  arm
harness assembly, engineering plastics, a variable resistance
chip  assembly  and  detachable  nylon  sliding  chip.  Variable
resistance plastic film is connected to the retained to the fuel
tank  plastic  bracket.  The  fork  with  a  brush  metal  contact  is
connected to the detachable nylon sliding chip. According to
the location, the sliding chip provides variable resistance to the
instrument cluster circuit. The resistance range is 40-300 Ω.
Circuit wiring harness leads from the variable resistance film
and extends to and fuel pump harness connector.

8. Fuel Rail

Fuel rail consists of the following:

–

Fuel Delivery Pipes To Each Fuel Injector

–

4 Independent Fuel Injectors

Fuel rail is installed in the intake manifold, and provides fuel to
each cylinder through the respective fuel injectors.

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9. Fuel Injectors

Fuel injector is a solenoid valve device controlled by the engine
control  module.  When  the  engine  control  module  provides
power supply to the fuel injector coil, normally closed ball valve
opens,  allowing  fuel  flow  through  the  diffuser  plate  to  fuel
injector outlet. Diffuser plate has a hole, used to control fuel
flow and form a double cone-shaped fine spray of fuel at the
fuel injector outlet. The fuel is sprayed into the two intake valve
channel from the fuel injectors, so that the fuel will be further
atomized before entering the combustion chamber. If the fuel
injectors have the following conditions, it will lead to various
vehicle dynamic performance malfunction:

–

If the fuel injector can not be opened.

–

If the fuel injector is stuck at the opening position.

–

If the fuel injector leaks.

–

If  the  fuel  injector  coil  resistance  is  too  low.  The  normal
resistance range is: 11.6-12.4 Ω.

10. Fuel Pipe O-ring

O-ring seals fuel system screw joints. Fuel System O-ring is
made from a special material.

Note

The fuel pipe O-ring is not a serviceable part.

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2.3.3 System Working Principle
2.3.3.1 System Working Principle

Intake  manifold  absolute  pressure  sensor  senses  and
measures intake manifold vacuum. When the fuel demand is
high, the intake manifold absolute pressure in a low-vacuum
state, such as the throttle fully open. Engine control module
uses this information to enrich the mixture, thereby increasing
the fuel injector opening time and injecting the correct amount
of  fuel.  When  the  engine  decelerates,  the  intake  manifold
absolute  pressure  sensor  detects  increase  in  the  vacuum
degree, the engine control module requests to shorten the fuel
injector  opening  time,  reducing  the  amount  of  fuel  injection
according to the change.

1. Startup Mode

When  the  ignition  switch  is  turned  on,  the  engine  control
module  connects  to  the  fuel  pump  relay  2  s.  Then,  the  fuel
pump fuel pressure is established. Engine control module also
Check  the  engine  coolant  temperature  sensor  and  throttle
position sensor to determine the most appropriate Air-Fuel ratio
to  start  the  engine.  Engine  control  module  controls  the  fuel
supply by changing the fuel injectors opening and closing time.
This is achieved by controlling the fuel injectors with very short
pulses.

2. Acceleration Mode

Engine  control  module  responds  to  throttle  position  and  the
rapid changes in airflow and provides additional fuel.

3. Deceleration Mode

Engine control module responds to throttle position and gas
flow  rate  changes  and  reduces  the  fuel  amount.  When  the
speed  rapidly  decreases,  the  engine  control  module  can
completely cut off fuel supply.

4. Battery Voltage Calibration Mode

When the battery voltage is too low, the engine control module
uses  the  following  methods  compensate  for  a  weak  ignition
spark:

–

Increase fuel injector pulse width.

–

Increase idle speed.

–

Increase the ignition duration.

5. Stop Fuel Supply

When the ignition switch is turned off, the fuel injector will not
provide fuel. This prevents the continued combustion or engine

can  not  shut  down.  In  addition,  if  the  reference  pulse  is  not
received, there will be no fuel supply, in order to prevent fuel
overflow.

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2.3.4 Component Locator
2.3.4.1 Fuel Filler

FE02-2018b

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