Chery SQR 7160 sedan. Manual — part 124

Part II

M&M MULTI-PORT ELECTRIC INJECTION ENGINE

SYSTEM

Operation And Maintenance Instruction

For SQE480ED Engine Sequential Multi-port Fuel

Injection System

1. Description

SQR480Ed electric injection utilize M&M sequential multi-port fuel injection system

which is of λSpeed Density Type ( engine speed, air density, air/fuel mixture control)

and can control sequential fuel injection and distributor less ignition.

The system consists of 4 essential parts.

1：Air system 2：Fuel Supply System 3：Control system 4：Ignition system

1.Fuel Tank 2.Fuel pump 3.Multi-function valve 4.Check valve 5.Fuel Feed Pipe 6.Engine

ECU 7.Battery 8. Ignition switch 10.system relay 11.A/C compressor 12.Carbon

canister solenoid 13.Fuse 14 Active carbon canister 15. Anti-theft unit 16.Absolute

pressure and temperature sensor 17.Crankshaft speed and position sensor 18.Spark

plug 19. Coolant temperature sensor 20. Fuel injector 21. Throttle position sensor

22.idle step motor 23. Fuel rail 24. Air Filter 25. Ignition coil 26. Oxygen sensor

27. Warning Indicator 28. RPM sensor 29. way catalyst converter 30. Knock sensor

2. Operation Theory

The system enable the actual measured air/fuel ratio to approach chemical reaction

equivalent proportion, protecting 3 way catalyst converter and reducing exhaust pollution.

Oxygen sensor real-time analyzes oxygen content of exhaust , which enables ECU to

Fig 1 SQR480ED Electric Injection System Theory Illustration

correct air/fuel ratio by controling injected fuel quantity.

Fuel is directly sprayed into intake manifold beside the intake valve under pressure of

3.5bar. The fuel injector of each cylinder takes correspondingly phase control upon

sequence of air intake and open time of intake valve. Injection terminal is stored in ECU

MAP Diagram and will change with engine speed and intake manifold pressure. ECU can

correct all basic control strategy of engine under all operation condition upon signals from

various sensors in the system.

Idle speed is kept steady by step motor controlling by-pass valve opening and changing

ignition advance angle. Idle speed cannot be regulated manually.

The system utilize inductive discharge ignition, and control time is managed by power

supply module in ECU. Advance angle of ignition is calculated upon engine compression

pressure ratio and air intaked.

3. Fuel Injection System Control Strategy

3.1 Start-up

During the start-up of engine, ECU injects fuel to all cylinders simultaneously to

reduce start-up time, and then injects in phase sequence.

3.2 Idle speed

After start-up, engine needs idling for several minutes to warming up. The normal idle

speed is 880±50rpm(coolant temperature≥85℃). When engine is cold, engine runs at a

high idle speed warming up under the ECU control. With rising of coolant temperature, idle

speed decrease to normal speed gradually. When engine idles, if A/C is turned on, ECU will

increase idle speed by 100rpm.

3.Accelarating

During accelerating, ECU adds fuel injection upon engine load increasing and handles

signals from throttle position sensor, intake manifold absolute pressure sensor and Top Dead

Center/speed sensor. “ Basic Injection Time” multiplies a correction coefficient calculated

upon engine coolant temperature, throttle opening rate and intake manifold pressure

increment. When the injector is closed, if fuel injection time is calculated to have an abrupt

change, ECU will add fuel injection time according to above-mentioned factor, namely

reopen injector and compensate fuel injection as much as possible.

4. Decelerating

During decelerating, engine should reduce fuel injection to decrease exhaust pollution.

ECU identify this stage by high level to low level throttle potentiometer signal but not to

idle speed, and using buffer strategy to reduce torque output. When throttle potentiometer

signal shows throttle is closed and engine maximum limit speed reaches, ECU will regard

the condition is met and reduces by-pass air charge by step motor.

5. fuel cuttingoff

ECU will carry out fuel cutting-off stragety when warm engine speed is over 150rpm

and an idle speed position throttle (throttle potentiometer signal) is identified. During engine

warming up, ECU takes an engine speed of which engine water temperature increasing

strategy works. When throttle is not closed and warm engine speed is less than 1400rpm, it

will recover fuel supply.

6. Full load

When engine is under full load, ECU will prolong basic injection time to obtain the

maximum output power and guarantee 3 way catalyst converter temperature is within

specification.

7.Speed limit

When engine speed exceeds threshold valve for10 seconds or instantaneously exceeds

a specified threshold value , ECU will stop injection control function. When speed returns

to normal, ECU restart injection control.

8. Atmosphere pressure correction

The atmosphere pressure changes with altitude, which brings change of volume

efficiency.and needs to correct the basic calibration (injection time and by-pass air charge).

9. Self-adapting

ECU has air/fuel ratio self-adapting ability and can stores difference between basic

MAP diagram and correction value of oxygen sensor during operation. These differences

will be stored permanentlyallowing system and components to be correct gradually as a new

one. This function contains automatic conformance check and automatic diagnosis of

memory parameter.

10. Power balance

When normal electrical components operating cause battery voltage below 12.2V, the

electricity demand of electrical components is over than generator ability. ECU will

gradually increase engine idle speed to generate enough electricity energy. When power

balance is positive, increased idle speed will cancel.

4. Structural composition

4.1 Fuel supply system

The fuel supply system is semi-none-fuel-return type, only one pipe connecting fuel

tank and fuel rail. The system has the following advantages:if accident occurs, the fire

hazard possibility will be lowered to minimum by none-fuel-return pipe, little fuel vapor in

fuel tank, low fuel temperature in fuel tank.

The fuel supply system includes: electric fuel pump, diaphram fuel pressure regulator,

fuel pipe, fuel filter, fuel rail, quick coupler, fuel injector etc.