Chery A18. Manual — part 42

Installation of fuel filter:

——

Set up fuel filter assembly in fuel filter

protection box assembly.

——

Connect import and export tube in both end of
fuel filter, clamp tube lock hoop by special
tool.

——

Using two M8 lock nuts to install protection
box assembly under vehicle ground board.
Tighten bolts, and the tightening torque is 30
±3Nm.

Installation of fuel tube:
——Set up lock clamp on relevant screw under

vehicle body.

——Cover protective sleeves, set up fuel tube on

relevant lock clamp.

——Cover hose protection bushing, connect

relevant tube and hose.

——Clamp tube lock hoop by special tool

Caution

·Fuel pipe can not be bent excessively.

·After insert the quick release connector,

please pull and push the quick release

connector several times to confirm it

insert in position.

Assembly and disassembly of fuel pump and
fuel level sensor:

——Lay down back seat backrest forwards, lift

carpet on back cabinet, remove 3 tapping
screws on fuel pump cover, and then take
down the cover.

——Loosen fast joint on import and export tube,

disassemble import and export tube.

——Remove fuel pump plug, rotate fixed outer

collar

of

fuel

pump

assembly

in

counter-clockwise, slowly bring forward fuel
pump assembly.

——Pull out fuel level sensor with little upwards

strength.

Installation of accelerator cable:

——Install rubber jacket on vehicle front

boarding.

——Thread accelerator cable through rubber

jacket, then push it to right position.

——Install hook of accelerator cable in gluey

block of accelerator pedal.

——Install the other end of accelerator cable on

throttle valve rocker of throttle valve body.

——Adjust degree of tightness of accelerator

cable, located by locating clamp.

Caution

·When adjusting degree of tightness of

accelerator cable you should ensure
that: Accelerator pedal doesn’t need
any part of empty stroke at idle; when
throttle is full open, accelerator pedal
limiting screw assembly is effective
(accelerator

pedal

can

step

on

accelerator

pedal

limiting

screw

assembly).

Adjusting of accelerator cable:

Range of free travel : 1.0～3.0mm

OPERATION CONTROL OF ENGINE FUEL SUPPLY SYSTEM

1. Start engine:

In start process, ECU firstly inject to all cylinder at the same time to shorten start time. After
that, ECU will inject according to phase order.

2. Acceleration:

In acceleration process, ECU will add injection fuel by engine requirement and deal with
sensor signal below: throttle position, absolute pressure, upper dead center/ speed sensor,
multiply “basic” fuel injection time by a modification factor, which is calculated from engine
cooling temperature, throttle opening speed, and intake manifold pressure increment. When
injector is closed and if calculated injection time has a sudden change, ECU will add injection
Fuel by the modification factor mentioned above, that is to re-open injector (extra pulse) for
compensating fuel as soon as possible. In order to make vehicle more comfortable, torque
control strategy doesn’t affect performance and fuel consumption in accelerating by adjusting
spark advance angle. Because exhaust regulatory become much more Stricter, a kind of much
more complicated active manage strategy is developed, which utilize some physics and
hydrokinetics phenomenon (such as fuel film mode) to gain not only a sudden change in
throttle air input but also steady air fuel ratio.

3. Deceleration:

In deceleration process, fuel engine needed is decrease to reduce pollution, ECU identifies
the phase by that throttle potentiometer signal change from high level to low level but do not
back to idle. Furthermore, it can adopt dashpot strategy to decrease output torque (reduce
engine brake), when throttle potentiometer signal shows that throttle is closed and engine is
in very high speed, ECU considers it’s satisfied condition that ECU will minish by-pass air
input by controlling step motor step by step.

4. Cut off:

ECU will adopt cut off strategy when ECU identifies that throttle is in idle position (throttle
potentiometer signal) and hot engine speed exceeds 1500r/m. The warm up strategy is
determined by the speed when engine coolant temperature increase strategy is running. Fuel
will be supplied again to system if throttle is not closed and hot engine speed is lower than
1400r/m. In high speed, ECU will adopt cut off strategy (part cut off) if throttle is not closed
completely but manifolds pressure is very low.

5. Full load:

In full load status (distinguished from throttle potentiometer and absolute pressure sensor),
ECU obtains maximal output power by increase basic fuel injection time, while temperature
of catalysis converter is kept in prescriptive range.

6. Air pressure modification:

Air pressure will change with different altitude, which will cause change to volumetric
efficiency. That is why basic specified parameter (fuel injection time and by pass air input)
need to be modified. Fuel injection time modification and by pass air input compensation is
decided by altitude change, and ECU will refresh those parameters automatically when
start, or does dynamic modification (air pressure dynamic modification) on a certain
throttle position and engine speed.

.

7. Engine speed limitation:

When engine speed has exceeded “critical” value for 10 seconds or instantly exceeds a
certain value prescribed by manufacturer, ECU will cut off fuel injector control function.
ECU will rebuild fuel injector control function when speed comes back to normal value.

8. Fuel pump:

- When engine speed is lower than a certain value close fuel pump (approx, 50r/m);

- Open ignition switch for 2 seconds, but engine does not start fuel pump;

- Fuel pump keeps working when engine is running or vehicle is in its way.

9. Self adapting:

ECU has self adapting function for air fuel ratio. ECU can store difference between basic
pulse diagram and oxygen sensor modification factor continuously generated in running. The
difference will be permanently stored because of ageing of engine and system components. It
permits system to amend engine and components as new.

This function includes automatically consistency test and automatically diagnosis for stored
parameters, special diagnosis instrument can delete those parameters, and modification
parameters will not be lost if batter or ECU is cut off. This strategy is ineffective if canister
solenoid valve is open. After changing ECU, it should run at idle (warm up) for some time
to make ECU restore modification parameter. When engine is in high speed, modification
parameter in memory is the parameter of normal running condition. ECU another self
adapting function can modify step motor opening degree change caused by throttle leakage
and engine natural ageing. The self adaptive parameter will be lost when power off or ECU is
cut off.