mt80 engine management system

Chery Fengyun 2 Service Manual

(MT80 Engine Management System)

After-Sales Service Department, Chery Automobile Sales Co., Ltd.

Contents

Section I Engine Electronic Fuel Injection System..............................................................................................4

Chapter I Introduction to the Engine MT80 Electronic Fuel Injection System for Fengyun 2 Model............4

I. System Introduction............................................................................................................................4

1. Fuel Pump Control Strategy..............................................................................................................4

2. Pilot Injection for Starting..................................................................................................................4

3. Protective Fuel Cut-off Control..........................................................................................................4

4. Function Features of the Engine Management System....................................................................5

5. Features of ECM in the Engine Management System......................................................................5

6. Coil Magnetizing Control...................................................................................................................5

7. Starting Mode....................................................................................................................................5

8. Idle Speed Control.............................................................................................................................6

9. Knock Control Logic..........................................................................................................................6

10. Charcoal Canister Solenoid Valve Control Logic............................................................................7

11. Fan Control Logic............................................................................................................................7

12. Working Conditions of the Air Conditioner......................................................................................7

13. Air Conditioner Shutdown Modes....................................................................................................7

Chapter II Introduction to the Input Elements of the Engine MT80 Electronic Fuel Injection System for

Fengyun 2 Model..........................................................................................................................................8

1. Crankshaft Position Sensor (CKP)...........................................................................................................8

1.1 Position and Function......................................................................................................................8

1.2 Principle...........................................................................................................................................9

1.3 Measurement...................................................................................................................................9

2. Camshaft Position Sensor (CMP)...........................................................................................................10

2.1 Position and Function....................................................................................................................10

2.2 Principle.........................................................................................................................................10

2.3 Measurement.................................................................................................................................11

3. Accelerator Petal Position Sensor (APP)................................................................................................11

3.1 Structure and Principle..................................................................................................................11

3.2 Measurement.................................................................................................................................12

4. Throttle Position Sensor (Electronic Throttle).........................................................................................13

4.1 Structure........................................................................................................................................13

4.2 Working Principle of the Electronic Throttle Motor........................................................................13

4.3 Measurement.................................................................................................................................14

5. Engine Coolant Temperature Sensor (ECT)..........................................................................................15


5.2 Principle.........................................................................................................................................15

5.3 Measurement.................................................................................................................................15

5.4 System Trouble Caused by Element Trouble...............................................................................16

6. Manifold Absolute Pressure/Temperature Sensor.................................................................................16


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Working Principle.................................................................................................................................16

6.3 Measurement.................................................................................................................................17

6.4 Working Parameters......................................................................................................................17

7. Oxygen Sensor.......................................................................................................................................18


7.2 Performance..................................................................................................................................18

7.3 Structure and Principle..................................................................................................................19

8. Knock Sensor.........................................................................................................................................20


8.2 Principle.........................................................................................................................................20

8.3 Measurement.................................................................................................................................20

9. Electronic Control Unit (ECU).................................................................................................................21


9.2 Structure........................................................................................................................................21

9.3 ECU Parameters...........................................................................................................................21

9.4 Measurement.................................................................................................................................22

10. Ignition Coil...........................................................................................................................................22

10.2 Performance................................................................................................................................23

10.3 Working Principle.........................................................................................................................23

10.4 Measurement...............................................................................................................................23

10.5 System Trouble Caused by Element Trouble.............................................................................24

11. Electromagnetic Fuel Injector...............................................................................................................25

11.1 Position and Function..................................................................................................................25

11.2 Structure and Working Principle..................................................................................................25

11.3 Measurement...............................................................................................................................26


12. Charcoal Canister Control Valve..........................................................................................................27

12.1 Position........................................................................................................................................27

12.2 Function.......................................................................................................................................27

12.3 Structure and Working Principle..................................................................................................27

12.4 Measurement...............................................................................................................................28

12.5 Working Conditions of the Charcoal Canister Solenoid Valve....................................................28

13. Electric Fuel Pump................................................................................................................................29

13.1 Structure......................................................................................................................................29

13.2 Measurement...............................................................................................................................30


14. Steel Fuel Distribution Pipe Assembly..................................................................................................30

15. Anti-theft Input Signal...........................................................................................................................31

15.1 Position and Function..................................................................................................................31

15.2 Structure and Working Principle (Anti-theft Controller)...............................................................31

15.3 Structure and Working Principle (Transponder)..........................................................................32

15.4 Structure and Working Principle (Reader Coil)...........................................................................32

15.5 Matching of the Key.....................................................................................................................32

15.6 Matching of the Anti-theft System...............................................................................................33

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Section I Engine Electronic Fuel Injection System

Chapter I Introduction to the Engine MT80

Electronic Fuel Injection System for Fengyun 2 Model

I. System Introduction

The Fengyun 2 series car is equipped with ACTECO series SQR477F engine, which is developed by Chery Automobile Co., Ltd. together with AVL Company, a world-famous engine design company, and designed with excellent performance.

The SQR477F engine is provided with Delphi MT80 engine management system which is based on torque control and electronic throttle and featured by computer closed-loop control, sequential multipoint fuel injection, grouping direct ignition without current distributor and post-processing of three-way catalytic converter.

1. Fuel Pump Control Strategy

1.1.1 Fuel Pump Control Logic

Fuel pump start logic:

After the ignition switch is turned on, the fuel pump will run for 2s. If no effective 58X signal is detected, the fuel pump stops and the engine begins to rotate. Once the ECU detects an effective 58X signal, the fuel pump starts.

Fuel pump stop logic:

In 0.6s after the rotation speed signal disappears or in case that the anti-theft device requires shutdown of the fuel pump, the fuel pump will stop.

2. Pilot Injection for Starting

The pilot injection for starting is performed only once in the course of normal start, and the conditions are as follows:

1. The engine is under operation;

2. The fuel pump relay picks up;

3. The running time of the fuel pump exceeds the pressure accumulation delay time;

4. The pilot injection for starting has not been performed before.

Once the above conditions are met, the pilot injection for starting will be performed in all cylinders at the same time.

3. Protective Fuel Cut-off Control

Once any of the following conditions is met, the system will stop fuel injection:

The fuel supply is cut off when the engine rotation speed is higher than 6400rpm, is recovered

when the engine rotation speed is lower than 6000rpm, and is cut off when the system detects any trouble in the ignition system.

The fuel supply is cut off when the system detects any trouble in the ignition system.

When the system voltage exceeds 18V, the system enters electronic throttle function limit mode (forced idling mode).

4. Function Features of the Engine Management System

Manifold absolute pressure/temperature sensor control:

1. Engine torque output control mode

2. Main power supply relay control of the complete vehicle

3. Closed loop control sequential multipoint fuel injection

4. Fuel supply mode without fuel return

5. Fuel pump working control

6. Knock control

7. Electronic throttle control

8. Air conditioner control

9. Cooling water tank fan control

10. Charcoal canister solenoid valve control

11. System self-diagnosis function

12. ECU anti-theft control

13. ECU built-in ignition drive module, grouping direction ignition without current distributor

5. Features of ECM in the Engine Management System

1. ECU developed for the high-end electronic fuel injection system market

2. State-of-the-art electronic hardware technology

3. 2-bit microprocessor (CPU) with sufficient memory and high computing speed

4. High cost performance

5. Flexible I/O ports

6. In accordance with the current Euro IV and EOBD

6. Coil Magnetization Control

The magnetizing time of the ignition coil determines the ignition energy of the spark plug. Too long magnetizing time will damage the coil or the coil drive, while too short magnetizing time will lead to misfire.

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7. Starting Mode

Under the starting mode, the system applies a fixed ignition angle;

Main ignition advance angle:

The main ignition advance angle refers to the minimum timing for the best torque (MBT) or the knock borderline (KBL) timing.

Correction of the ignition advance angle:

1. Correction by water temperature;

2. Correction by air intake;

3. Correction by altitude compensation;

4. Correction by idling;

5. Correction by acceleration;

6. Correction by power enrichment;

7. Correction by deceleration and fuel cut-off;

8. Correction by air conditioner control.

8. Idle Speed Control

Basic target idle speed

Under different coolant temperatures, the basic target idle speed is set as follows:

Coolant

temperature

℃

Target

idle

speed

rpm

Coolant

temperature

℃

Target

idle

speed

rpm

Coolant

temperature

℃

Target

idle

speed

rpm

Coolant

temperature

℃

Target

idle

speed

rpm

<-20 1175 20 1150 60 850 100 750

-10 1200 30 1150 70 800 110 750

0 1200 40 1000 80 750 >120 800

10 1150 50 900 90 750

9. Knock Control Logic

Working conditions for knock control:

1. Then engine runs for over 2s;

2. The engine water temperature exceeds 70 ;℃

3. The engine rotation speed exceeds 800rpm.

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After detecting any knock, the system will, based on the engine rotation speed, quickly change the ignition advance angle by 3~5 degrees for ignition delay and return to normal control within the subsequent 2~3s.

10. Charcoal Canister Solenoid Valve Control Logic

Before the charcoal canister solenoid valve opens, the following conditions must be met:

1. The system voltage is higher than 8V but lower than 18V;

2. The engine water temperature exceeds 0 ;℃

3. The engine intake temperature exceeds 0 ;℃

4. There is no related system trouble.

The opening of the charcoal canister solenoid valve depends on the duty ratio signal determined by the ECU according to the engine state.

11. Fan Control Logic

The working modes and conditions of the fan are as follows:

1. When the water temperature exceeds 95 , the low-speed fan starts;℃

2. When the water temperature exceeds 99 , the high-speed fan starts;℃

3. When the water temperature is lower than 95 , the high-speed fan stops;℃

4. When the water temperature is lower than 90 , the low-speed fan stops;℃

5. When the air conditioner is switched on, the air conditioner fan starts.

12. Working Conditions of the Air Conditioner

The air-conditioning system will start when the following conditions are met:

The engine runs for over 7s;

The air conditioner switch is turned on;

All air conditioner shutdown modes are out of function.

13. Air Conditioner Shutdown Modes

Air conditioner shutdown mode in case of high engine rotation speed: protect the

air-conditioning system:

With the air conditioner shut down, the compressor can be started only when the engine rotation speed is lower than 4900rpm.

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With the air conditioner under operation, the compressor will be stopped when the engine rotation speed exceeds 5100rpm.

Air conditioner shutdown mode in case of high engine coolant temperature:

protect the air-conditioning system:

With the air conditioner shut down, the compressor can be started only when the coolant temperature is lower than 106 .℃

With the air conditioner under operation, the compressor will be stopped when the coolant temperature exceeds 108 .℃

Air conditioner shutdown mode in case of low air conditioner evaporator

temperature: protect the air-conditioning system:

When any of the following conditions is met, the vehicle will enter the air conditioner shutdown mode in case of starting at high ambient temperature:

The air conditioner evaporator temperature sensor is defective;

The temperature of the air conditioner evaporator is lower than 3 ;℃

When the following two conditions are met, the vehicle will exit from the air conditioner shutdown mode in case of low air conditioner evaporator temperature:

The air conditioner evaporator temperature sensor is in good condition;

The temperature of the air conditioner evaporator exceeds 4 .℃

Chapter II Introduction to the Input Elements of the Engine MT80

Electronic Fuel Injection System for Fengyun 2 Model

1. Crankshaft Position Sensor (CKP)

1.1 Position and Function

Position: The crankshaft position sensor is installed at the front part of the transmission housing and aligned with the flywheel outer ring.

Function: It is used to detect the rotation position and speed of the engine crankshaft and output a corresponding signal by which the ECU determines the rotation position and speed of the engine crankshaft.

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Clearance between the sensor and the ring gear Coil resistance Coil inductance

0.3~1.5mm 560Ω±10% 240mH±15%

1.2 Principle

1. Permanent magnet

2. Crankshaft sensor casing

3. Transmission housing

4. Soft iron core

5. Coil

6. Backlash (reference mark)

7. Air clearance

1.3 Measurement

The crankshaft position sensor is a magnetic inductive rotation speed sensor. Due to low induced voltage, the sensor is easily influenced by the ambient electric wave, so its connecting wires are added with a shielding layer. The plug is provided with three terminals as below:

A: Signal +;

B: Signal -;

C: Shielding wire.

Measurement with a Universal Meter: Waveform Output by the Sensor (Measured with an Oscillograph)

Measure the resistance to ground of each terminal with a universal meter set at Ohm range to find out the shielding wire connector, and then measure the resistances of the other two connectors. Afterwards, preliminary judgement for the sensor state can be made by comparing the measuring results with the technical parameters.

Waveform Output by the Sensor (Measured with an Oscillograph)

A B C

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2. Camshaft Position Sensor (CMP)


Position: It is set at the rear part of the valve chamber cover. The signal gear is installed at the rear part of the camshaft and runs in synchronicity with the camshaft.

Function: It is used to provide the phase information of the camshaft to the ECU to judge which stroke the engine is in during a working cycle.

Performance

Working voltage Working clearance

4.5~13V 0.3~2mm

2.2 Principle

Hall principle:

The integrated circuit is set in front of one pole of the permanent magnet; with the Hall principle, when the camshaft drives the signal gear to rotate, the change of tooth profile leads to change of magnetic force line in terms of intensity, resultng in output of voltage signal.

Characteristic curve

The characteristic curve is coordinated with the crankshaft signal, namely, the crankshaft rotates for two circles and the camshaft rotates for one circle, by which the top dead center of cylinder 1 can be determined.

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Waveform Graph Measured with an Oscillograph

2.3 Measurement

Wire A is a signal wire, connected to ECU E56#;

Wire B is a signal ground wire, connected to ECU E18#;

Wire C is a 5V power wire, connected to ECU E23#.

3. Accelerator Petal Position Sensor (APP)

Position: It is set under the instrument panel at the drive’s side and above the accelerator pedal.

Function: It is used to feed back the position of the accelerator pedal to the ECU by means of electronic signal, and then the ECU will control the electronic throttle by computation.

3.1 Structure and Principle

It is a non-contacting position sensor which may improve the signal reliability. Besides, it is provided with two Hall sensors, without the need for self-learning.

Trouble Phenomena:

The engine trouble indicator lamp is on;

Poor acceleration;

Limited engine rotation speed.

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1. Signal

2. Grounding

3. Live wire

4. Signal

5. Grounding

6. Live wire

3.2 Measurement

When the ignition switch is turned on, the engine is not started, and the accelerator pedal is not stepped, sensors APP1 and APP2 will output the following voltage signals.

APP1: 2.18V;

APP2: 0.21V.

2. When the ignition switch is turned on, the engine is not started, and the accelerator pedal is stepped to the end, sensors P1 and P2 will output the following voltage signals.

APP1: 4.71V;

APP2: 0.84V.

All the above values are measured with a diagnostic tester when the engine is under normal condition, and are for reference only.

Waveform Graph of the Accelerator Pedal Stepped to the End

Waveform Graph of the Accelerator Pedal

Waveform Graph of the Accelerator Pedal under Free State

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4. Throttle Position Sensor (Electronic Throttle)

Position: The throttle position sensor is set on the electronic throttle.

Function: It is used to monitor the positions of the throttle and force motor.

4.1 Structure

Constitution:

1) Throttle body;

2) Drive motor;

3) Throttle position sensor.

The sliders of the two potentiometers are directly connected with the throttle spindle, of which one potentiometer outputs a positive signal and the other outputs a negative signal.

4.2 Working Principle of the Electronic Throttle Motor

The throttle drive motor is a DC micromotor. It drives a set of particular gear reduction unit and a double-acting spring. When the system is power-off, it keeps the throttle valve plate at a safety opening position leading to a moderate speed higher than the idle speed, so as to ensure the vehicle can travel continuously. If the electronic control system of the engine enters this trouble mode, the electronic throttle valve plate won’t act when the accelerator pedal is stepped.

TPS1

The sensor signal potential increases with the change of the opening.

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TPS2

The sensor signal potential decreases with the increase of the throttle opening.

4.3 Measurement

Resistance of the DC motor: 3.93Ω

Measure the voltage variation of wires B and C.

The variation trends of the two voltages are opposite;

A. 5V power supply

B. Signal

C. Signal

D. Grounding

The electronic throttle drive motor is a DC motor with two wires.

E: ECU E67# driven by the motor

H: ECU E61# driven by the motor

D: ECU E04#

B: ECU E39# position sensor signal 1

A: ECU E03#

C: ECU E26# position sensor signal 2

Unplug the electronic throttle and use a universal meter set at Ohm range to measure the resistances of wires H and E. If both the wires are under conducting state and with small resistances, the throttle drive motor is in normal condition. The measured resistances of wires H and E are about 0.6Ω.

Waveform Graph of the Throttle Position Sensor

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5. Engine Coolant Temperature Sensor (ECT)


Position: It is set at the cylinder head water outlet at the rear part of the engine and under the ignition coil.

Performance:

5.2 Principle

It is a negative temperature coefficient (NTC) thermistor.

The resistance reduces with the increase of the coolant temperature. However, the resistance is not in linear relationship with the coolant temperature.

5.3 Measurement

Measurement with a Universal Meter:

Pull out the connector, set the universal meter at Ohm range, and connect the two probes with pins 1# and 2# of the sensor respectively for measurement. The rated resistance is 2.5kΩ±5% at 20 .℃

Working voltage Working temperature

5V -40~135℃

Water temperature sensor

Engine coolant

temperature

ECT sensor resistance

characteristic

Large

Small

HighLow

Resistance

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5.4 System Trouble Caused by Element Trouble

In case of any trouble, the following phenomena may appear:

Difficult cold start;

Difficult hot start;

Poor driving performance;

If the sensor is short to power supply, the engine will run at the default;

High temperature indicated by the thermometer;

Low temperature indicated by the thermometer;

The cooling fan runs under quick mode continuously;

When the indicated temperature is low, the high temperature warning lamp flashes.

6. Manifold Absolute Pressure/Temperature Sensor


Position: It is set on the manifold resonant cavity.

Performance:

The manifold absolute pressure/temperature (MAP/MAT) sensor incorporates the functions of the manifold absolute pressure sensor and the manifold absolute temperature sensor, so as to feed back the manifold absolute pressure and temperature simultaneously. The pressure sensor is used to measure the air inhaled by the engine and it is an important element for making up the speed-density type air flow metering system.

Working Principle

The manifold absolute pressure (MAP) sensor is provided with a sealed elastic diaphragm and an iron magnetic core which are precisely set in the coil. When the pressure changes, an output signal in direct proportion to the input pressure and in proportion to the reference voltage will be generated.

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6.3 Measurement

6.4 Working Parameters

Working voltage Working current Output voltage Output impedancePressure

range

Working

temperature

5V Max. 12mA -100~100mV <10Ω 10kP~110kP -40~125℃

Waveform Graph of the Manifold Absolute Pressure Sensor

Brisk Acceleration (MAP) Deceleration (MAP)

Pressure (kP) 15 40 94 102

Output voltage (V) 0.12~0.38 1.52~1.68 4.44~4.60 4.86~5.04

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7. Oxygen Sensor


Position: The A13 car is provided with a front

oxygen sensor and a rear oxygen sensor, of which the former is set on the exhaust manifold and the latter is set behind the rear three-way catalytic converter (TWC).

Function: It is used to feed back the closed-loop control mixture signal.

7.2 Performance

Temperature 260℃ 450℃ 595℃

Output voltage in case of rich mixture

(mV)>800 >800 >750

Output voltage in case of weak mixture

(mV)<200 <200 <150

Response time from weak mixture to

rich mixture (ms)<75 <75 <50

Response time from rich mixture to

weak mixture (ms)<150 <125 <90

Internal resistance (Ω) <100K

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7.3 Structure and Principle

The oxygen sensor is an important typical part in the closed-loop fuel control system. It adjusts and keeps the desired air-fuel ratio to make the three-way catalytic converter achieve its optimum conversion efficiency.

When the air-fuel ratio involved in the engine combustion gets large, the oxygen content in the exhaust gas increases and the output voltage of the oxygen sensor drops; otherwise, the output voltage rises. In this way, the sensor feeds back the air-fuel ratio to the ECU.

The sensitive element in the oxygen sensor is made of zirconia and constructed with a hollow part and an external inductive part. After the zirconia element is activated by heating (>300 ),℃ the reference air enters its hollow part through the wire and the exhaust gas passes through its outside electrode so that the oxygen ions move from its center to outside electrode. In this way, a simple atomic battery is formed and a voltage is generated between the two electrodes. The zirconia element can change the output voltage according to the oxygen content in the exhaust gas so as to judge the oxygen content in the exhaust gas. Generally, the oxygen sensor is designed to generate a jump in the voltage magnitude when the air-fuel ratio determined based on the exhaust gas is close to the theoretical value (14.6:1) so as to help the ECU judge the air-fuel ratio precisely.

7.4 Measurement

Remove the connector, set the digital universal meter at Ohm range, and connect the two probes with pins C and D of the sensor respectively to measure the resistance, namely, heater’s resistance, which is 9.2Ω under room temperature (measured value). Connect the connector, set the digital universal meter at DC voltage range after the oxygen sensor reaches its working temperature 350 under idling state, and connect℃ the two probes with pins A and B of the sensor to measure the voltage which shall fluctuate quickly between 0.1~0.9V.

Waveform of the Oxygen Sensor

Waveform of the Oxygen Sensor (Brisk Acceleration)

20

8. Knock Sensor


Position: It is set under the intake manifold.

Function: It is used to monitor whether the combustion of the gas mixture in the engine combustion chamber has a trend of knock. If yes, it sends a knock signal to the ECU to help the ECU control the ignition advance angle better.

8.2 Principle

The knock sensor is a vibration acceleration sensor and generates an output voltage corresponding to the mechanical vibration of the engine. The sensor is provided with a ceramic piezolectric crystal whose vibration generates a voltage signal. During the knock of the engine, the crystal vibrates more seriously so as to change the output signal to the ECU.

8.3 Measurement

◆ Remove the connector, set the digital universal meter at Ohm range, and connect the two probes with pins 1# & 2# and 1# & 3# of the sensor respectively to measure the resistance which is over 1MΩ under room temperature. The terminals are independent from each other.

2. Set the universal meter at mV range, use a rubber hammer to beat the engine cylinder block and a voltage

Frequency response range Resistance Capacitance

3~18kHz <1MΩ 1480~2220pf

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shall be output from the sensor, or gently beat the sensor (don’t damage the sensor) and a voltage also shall be output from the sensor.

9. Electronic Control Unit (ECU)


Position: It is set on the floor under the instrument panel at the assistant driver’s side.

Function: The ECU is the core of the engine electronic control system. With the signals for electronic control from the sensors, the ECU, after internal computation, controls a series of actuators such as the fuel injector and ignition coil to control the working of the engine.

Working voltageOvervoltage and reverse voltage

protection

Working

temperature

1~16V +24V/-14V < 60s -40~105℃

9.2 Structure

It is composed of a shielded housing and a printed circuit board where lots of electronic control units are integrated for the control of electronic fuel injection.

This electronic control system is provided with an ECU anti-theft control system.

Note: The ECU housing and the fixing bolts must be insulated from the chassis.

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9.3 ECU Parameters

◆ CPU parameters;

◆ 32-digit master chip;

◆ 66M clock frequency;

◆ 1M FLASH on-chip memory;

◆ 12K RAM memory;

◆ 4K EEPROM memory.

Working Parameters

Normal working voltage range: 9.0V◆ ~16V;

Overvoltage and reverse voltage protection: +24V/-14V < 60s◆ .

9.4 Measurement

Simple measurement method:

◆ Connect the connector and read the engine trouble records by using the engine data diagnosis line;

◆ Remove the connector and check whether the ECU connecting wires are in good condition, especially check whether the ECU power supply and grounding circuit are normal;

◆ Check whether the external sensors work normally, whether the output signals are reliable and whether the circuits are in good condition;

◆ Check whether the actuators work normally and whether their circuits are in good condition;

◆ At last, replace the ECU for test.

10. Ignition Coil


◆ Ignition sequence: 1, 3, 4 and 2

Position: The ignition coil is set on the side of the engine upper cylinder head (next to the transmission).

◆ The ignition coil is used to transform the low voltage of

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the primary winding into the high voltage of the secondary winding, and then ignite the fuel-air mixture in the cylinder by the spark discharged by the spark plug.

10.2 Performance

Primary resistance 0.5±0.05Ω Secondary inductance 17.5±1.2H

Secondary resistance 9840±980Ω Interruption current peak 9.5A

Primary inductance 2.75±0.25mH Secondary output voltage 34kV

10.3 Working Principle

The ignition coil ZS-K2x2 is composed of two primary windings, two secondary windings, an iron core and a housing. When the grounding circuit of any primary winding is connected, this primary winding is charged. Once the ECU disconnects the primary winding circuit, the charging is stopped and a high voltage is induced in the secondary winding to make the spark plug discharge. Unlike the ignition coil with current distributor, each end of the secondary winding of the ignition coil ZS-K2x2 is connected with a spark plug, so both the spark plugs generate spark simultaneously. The two primary windings are energized and deenergized alternatively, and correspondingly, the two secondary windings discharge alternatively.

Coil resistance Min. working voltage Working temperature

12±0.4Ω 4.5V -40~130℃

10.4 Measurement

Use a universal meter set at Ohm range to measure the resistances of the primary coils of wires B and C as well as wires D and C respectively which are 0.45~0.55Ω.

Remove the high-tension wires of cylinders 1 and 4, and use a universal meter to measure the resistance between the high-tension wire connectors of the two cylinders, namely, the resistance of the secondary coil, which is 8.8~10.8kΩ.

SHIELD (dual-core

shielding)

24

A: Shielded ground wire

B: 12V power wire

C: ECU E17#

D: ECU E01#


◆ Unstable idling

◆ Insufficient engine power

◆ Increased fuel consumption

◆ Increased emission

Ignition Waveform II: Ignition Timing

Ignition Waveform: Ignition in Exhaust Stoke

25

11. Electromagnetic Fuel Injector


Position: It is set between the fuel rail and intake manifold and above the fuel rail.

Function: It is used to supply the atomized fuel to the engine by injecting fuel in a set time according to the command from the ECM. Besides, it is also used to store the high-pressure fuel to eliminate the resonance resulted by the operation of the fuel pump, so as to keep the pressure steady.

11.2 Structure and Working Principle

The electromagnetic controlled fuel nozzle is equippedwith a return spring in the shell to press the valve needle on the valve seat and the opening is sealed up.

For injection, the electronic controller sends a controlsignal to get the electromagnetic coil energized toproduce an electromagnetic field which is helpful in overcoming the pressure of the return spring, the gravity of the needle valve and the friction to lift up the needle valve. In this way, the fuel may be injected under the fuel pressure. There are only two states for the needle valve, namely, the valve is lifted up or lowered down, and its lift can not be adjusted. Provided that the pressure difference between the inlet and outlet of the fuel nozzle is constant, the fuel injection quantity will depend on the needle valve opening time, i.e., the opening electric pulse width. The lift of the needle valve shall not exceed 0.1mm.

Orifice plate

O-ring

Plastic particle

Adjusting sleeve

Coil

Spring

Guard strip

Needle valve component

Valve seat component

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11.3 Measurement

Measurement with a Universal Meter

There are two wires for the fuel nozzle connector, one of which is connected to the ECU and the other is connected to a 12V power supply.A: 12V power supply;

B: ECU E63#.

For measurement, remove the connector, set the universal meter to Ohm range and then connect the two probes with the two pins of the fuel injector respectively. The rated resistance at 20 is 11~16Ω.℃

Measurement with a Diagnostic Tester


In case of any trouble, the following

phenomena may appear:

◆ Poor idling, poor acceleration, failure in starting (difficulty in starting), etc.

◆ Failure due to the gum accumulated in the fuel injector as a result of lack of maintenance.

Waveform Graph of the Fuel Injector

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12. Charcoal Canister Control Valve

12.1 Position

◆ It is set at the right corner of the engine compartment and near the expansion valve.

◆ Specification

Rated working voltage 12V Working temperature 140~120℃

Working voltage range 8~16V Coil resistance 19~22Ω

Limited voltage 25V Coil inductance 12~15mH

12.2 Function

1. Connecting to the fuel tank

2. Charcoal canister

3. Air

4. Charcoal canister control valve

5. Connecting to the intake manifold

6. Throttle

12.3 Structure and Working Principle

The charcoal canister control valve consists of electromagnetic coil, armature, valve, etc. A filter screen is set on the inlet.

The air flow of the charcoal canister control valve depends on two factors, namely, the duty ratio outputted by the ECU to the charcoal canister control valve in the form of electric pulse, and the pressure difference between the inlet and outlet of the charcoal canister control valve.

In case the electric pulse is not available, the charcoal canister control valve will be closed. The ECU is used to control the power-on time of the charcoal canister solenoid valve according to the signals provided by the sensors of the engine, so

Seal ringValve component

CasingCore

Electromagnetic coil

Air flow direction

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as to control the cleaning air flow indirectly.

12.4 Measurement

◆ Failure Check

1) Conduct failure detection by measuring the resistance of the charcoal canister solenoid valve. It has two wires:

A: 12V power supply;

B: ECU E57#.

The ECU controls the on/off of the cleaning duct by the grounding of the charcoal canister solenoid valve. When measuring the resistance of the charcoal canister solenoid valve, remove the charcoal canister control valve harness connector to measure the coil resistance. It shall be 19~22Ω, otherwise, replace the coil.

2) Check the charcoal canister solenoid valve for failure when it is under operation.

12.5 Working Conditions of the Charcoal Canister Solenoid Valve

To minimize the affect of the fuel vapor towards the acting of the engine under normal combustion condition, the following requirements shall be met before the charcoal canister solenoid valve opens:

◆ The system voltage is higher than 8V but lower than 18V;

◆ The engine water temperature is higher than 0℃;

◆ The engine intake temperature is higher than 0℃;

◆ There is no related system trouble.

Waveform Graph for the Charcoal Canister Solenoid Valve Control

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13. Electric Fuel Pump

Position: It is set in the fuel tank.

Function: It is used to send the fuel from the fuel tank to the engine at certain pressure and flow rate.

13.1 Structure

1. Fuel pump end cover (integrated with check valve, relief valve and anti-electromagnetic interference elements)

2. Motor

3. Fuel duct

4. Blade pump

Normal working voltage: 8~14V

Normal working temperature: -30~70℃

System pressure: 400kPa

Output pressure

>350kPa Working voltage

8~16V

Keep-up pressure

≈24kPa Overvoltage protection

-13.5~26V

Output flow >10g/s Running without fuel

<60s

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13.2 Measurement

The fuel pump is a DC motor. It is controlled by the ECUwith the fuel pump relay.

Verification of Fuel Pump Working Status:

Turn on the ignition switch and the fuel pump will work for a shorttime. In this case, a sound arising from the running fuel pump will be heard.

86: Grounding

87: 12V power supply


Trouble Phenomena:

Great noise, poor acceleration, failure in starting (difficult starting), etc.

Common trouble cause: the application of disqualified fuel resulting in:

1. Insulating layer formed by the accumulated gum;

2. Locking of the fuel pump shaft bushing and armature;

3. Corrosion of fuel level sensor components, etc.

14. Steel Fuel Distribution Pipe Assembly

Position: It is set above the intake manifold.

Function: It is used to store the high-pressure fuel to eliminate the resonance resulted by the operation of the fuel pump, so as to keep the pressure steady.

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15. Anti-theft Input Signal

Anti-theft Controller

It is integrated with a microprocessor to realize such functionsas key identification and system matching. It can produce aninduction field to transmit the communication signals between the controller and the transponder.

Mechanical key Transponder coil


Position: The engine anti-theft ECU is fixed in the instrument panel at the driver’s side by bolts.

Function: This device functions directly against the engine, so it significantly improves the overall safety in terms of anti-theft performance.

15.2 Structure and Working Principle (Anti-theft Controller)

Anti-theft Controller:

The anti-theft controller mainly consists of microprocessor and peripheral elements. It is used for the communication between the transponder and the engine management system. If the verification for the transponder is done in a set time, the engine management system may allow the startup of the engine.

System status: When the engine is under anti-theft status (unauthorized startup), the engine trouble indicator lamp (or EPC lamp) will flash quickly. In this case, the engine can rotate but can not work.

Ignition lock cylinder

Key head

Coil

Electromagnetic field

Key casing

Transponder

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15.3 Structure and Working Principle (Transponder)

Transponder (key chip and remote control key):

It is set in the key handle. This transponder, without power supply, is of small size and long service life. With the excitation in the electromagnetic field, it receives the power supply signal and clock signal, and carries out communication with the anti-theft controller. For each vehicle, at most five transponders can be provided, i.e., five keys, and the key chip is only available for writing-in once.

Every key is provided with a unique code. Please get the new key from the dealers of Chery Automobile Co., Ltd.

15.4 Structure and Working Principle (Reader Coil)

Position: It is set on the lock cylinder of the ignition switch.

Function: It is used to read the key information from the key chip and send the signal to the anti-theft controller.

Structure: It is set in a black plastic cover around the ignition switch. Two coil harnesses are connected to the anti-theft controller.

Reader Coil

Working principle: The coil is fed by the regulated current from the anti-theft controller.

When the key is within 2cm (0.78in) away from the ignition coil, and the ignition switch is at “ACC” position, an electricity energy of a frequency of 125kHz will be sent from the coil to the anti-theft controller under the principle similar to that of an emitter. The anti-theft controller will modulate the received data and encode them again, and then compare them with the saved identification codes. If the data are correct, the engine can be started.

15.5 Matching of the Key

1. Plug the diagnostic connector;

2. Insert the key to be matched into the ignition lock and turn it to ON position;

3. Select “Anti-theft device” → “Anti-theft device matching” → “Input code”→ “Input safety code” on the option menu of the diagnostic tester, and then input the safety code/PIN code;

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4. Select “Key clearing” to clear the information for the key lost before;

5. Select “Key learning” for key learning;

6. If you want to match another key, insert the key, reset the diagnostic tester and repeat the steps 2, 3, and 5 as mentioned above.

Key Quantity Inquiry:

Use the diagnostic tester to inquire the quantity of the matched keys and the keys that can be matched.

15.6 Matching of the Anti-theft System

Matching of Anti-theft Controller (Anti-theft Module):

1. Turn off the ignition switch and replace the anti-theft controller;

2. Insert the key into the ignition lock and turn it to ON position;

3. Select “Anti-theft device” → “Input code” → “Set safety code” on the option menu of the

diagnostic tester;

4. Select “Anti-theft device” → “Anti-theft device matching” → “Read from EMS to anti-theft device” to match the electronic fuel injection system with the anti-theft controller;

5. Match the original keys with the new anti-theft controller one by one.

Input of Safety Code (PIN Code):

The safety code can be input only by the Chery’s special diagnostic tester. When inputting the safety code, pay attention to the case of the letters. In case of continuous incorrect input for certain times, the ECU will be locked permanently.

Note: This Service Manual is mainly about the MT80 electronic fuel injection system of A13+477+QR515 vehicles. The introduction about other parts will not be covered here.

No. of continuous incorrect input

Interval of ECU locking

0 0s

1 10s

2 10s

3 10min

4 20min

5 40min

6 80min

7 160min

8 320min

9 640min

10 1280min

More 1280min

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mt80 engine management system

Documents

working principle

system trouble

principle transponder

system introductionthe

function features

working conditions

working parameters

crankshaft position