Geely Emgrand X7. Manual part — 85

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

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 operating principle

2.3.3.1 System operating Principle

Intake manifold absolute pressure sensor senses and measures intake manifold vacuum. When the
fuel demand is high, the intake manifold absolute pressure is 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. Starting

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 inspects the
temperature sensor of engine coolant 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.

–

Improved idle speed.

–

Increase the ignition duration.

5. Oil cut-off mode

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 position

2.3.4.1 Fuel Filler Position

NL02-1005e

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2.3.4.2 Fuel Supply System

4

3

1

2

5

6

NL02-2269b

1 Filling

Tube

2 Filter

3

Fuel Level Sensor

4 Fuel

Pump

5 Fuel

Tank

6

Fuel Supply Hose

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