Geely Emgrand X7. Manual part — 163

2.12.2.2 Components Description

1. Engine Control Module (ECM)

Engine control module is a microprocessor with a single chip as the core. Its function is to process
data from various vehicle sensors to determine the engine's working condition, and controls each
engine actuator through various actuators.

ECM normal work voltage 9.0 V–16 V

Notes:

Although ECM has the over-voltage and reverse polarity voltage protection function, during the
repair process it is prohibited to connect the battery positive and negative wrong or apply voltage
higher than 15 V. Otherwise, it will cause damage to ECM and other electrical equipments.

2. Crankshaft Position Sensor

The crankshaft position sensor output can be used to determine crankshaft position and rotation
speed. The engine rotation speed and crankshaft position sensor are magnetic-electric sensors
installed near the crankshaft. When the crankshaft rotates, they work together with the 58X gear
on the crankshaft. The 58x tooth top and the alveolar pass through the sensor in different distances
when the crankshaft rotates. The sensor senses the reluctance change; the alternating reluctance
generates an alternating output signal. The 58x gear plate gap position aligns with engine top dead
center. When the cylinder No.1 reaches top dead center, the sensor aligns with the 20th tooth lower
edge. ECM uses this signal to determine crankshaft position and rotation speed.

Resistance Value of the sensor: 20-30℃（68-86℉）900-1100Ω.

Output Voltage: 400 mV at 60 rpm. The voltage increases as the speed increases.

3. Intake Air Pressure/Temperature Sensor:

This sensor detects intake manifold pressure change caused by engine load and speed changes.
These changes will be converted to the voltage output. When the engine decelerates, the throttle
body closes to result in a relatively low intake manifold absolute pressure output. Intake manifold
absolute pressure and vacuum degree is opposite. When the manifold pressure is high, the vacuum
degree is low. MAP sensor is also used to measure atmospheric pressure . This measurement is
completed as part of the MAP sensor calculation. When the ignition switch is turned on and the
engine is not running, the engine control module reads the intake manifold pressure as
atmospheric pressure, and adjusts the Air-Fuel ratio accordingly. With this kind of altitude
compensation, the system can maintain a low emission while maintaining maneuverability.

4. Camshaft Position Sensor (CMP)

Camshaft position sensor is a Hall-effect sensor which is installed in the vicinity of the intake
camshaft, and works together with camshaft signal wheel. The signal wheel is corresponding to
the specific engine position. ECM measures digital voltage signal through this sensor, therefore
determining the working cylinder of the engine and implementing one-to-one control. Engine
control module then calculates the actual sequence of fuel injection. If the engine is running when
the camshaft position sensor signal is lost, the fuel injection system will be converted to the
sequential fuel injection mode based on the final fuel injection pulse, while the engine continues to
run. If the engine starts after being shut down, the fuel injection sequence will be converted from
sequential injection to group injection. Even if the fault exists, the engine can be restarted.

5. Engine Coolant Temperature (ECT) Sensor

Engine coolant temperature (ECT) sensor is used to detect the engine operating temperature. ECM
provides the best control scheme depending on the temperature. The sensor uses a negative
temperature coefficient thermostat as the sensing element, when the coolant temperature rises, the
resistance decreases. At -30°C the resistance is 52,594 Ω; at 130 °C, the resistance is 77.5 Ω. The
sensors are installed in the main coolant path. The coolant temperature signal is important to the
ignition timing and fuel injection adjustment, while the signal is also transmitted to the instrument
panel (IP) and used to display the current engine working temperature.

6. Knock Sensor (KS)

Knock sensor is a frequency response sensor, installed at the engine block’s most sensitive part to

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knocking under the intake manifold. ECM uses knock sensor to detect knock intensity, so as to
adjust the ignition advance angle to effectively control knocking and optimize the engine power,
fuel economy and emission levels. If the engine knocking occurs, ECM will receive this signal,
filter out the non-knock signals and make the calculation. It determines the engine’s position in the
working cycle through the camshaft and crankshaft position sensor signals, according to which the
ECM figures out the knocking cylinder and then delays the ignition advance angle for this
cylinder until the knocking disappears. Then ECM advances the ignition advance angle until the
ignition angle is best suited for the operating conditions at that time. Due to weak sensor signals,
the sensor lead has a shielded cable. Its resistance is over 1M Ω (20-30℃) with the output signal
is greater than 17 mV/g in any case.

7. Oxygen

Sensor

Oxygen sensor is an important symbolic component in a close-loop fuel control system, which
adjusts and maintains the ideal Air-Fuel ratio, so that three-way catalytic converter achieves the
best conversion efficiency. When the Air-Fuel ratio for engine burning becomes thin, the oxygen
content in the exhaust increases, and oxygen sensor output voltage is reduced. On the contrary, the
output voltage increases to feedback the air- fuel ratio to ECM.

Oxygen sensor sensing material is Zirconia, hollow with an external sensing part. When the
Zirconia components are heated (>300℃) for activation, the reference air enters the hollow part of
the Zirconia component through the lead wire. The exhaust passes through the outer electrode, and
the oxygen ions move from the center of the zirconia to the outer electrode, which thus consists of
a simple atomic battery with a voltage between two electrodes; the Zirconia can alternate the
output voltage according to the oxygen concentration in the exhaust and therefore determine the
oxygen content of exhaust gas. Usually, the oxygen sensor is designed to generate a voltage
amplitude jump in the vicinity of the exhaust theoretical Air-Fuel ratio of (14.7:1) to help the
ECM determine the Air-Fuel ratio accurately.

8. Fuel

Injectors

The injector nozzle’s structure is an electromagnetic switch ball valve device. The both electrodes
from the coil are connected to the ECM and the power supply through the engine wiring harnesses.
When the coil is controlled by ECM to connect to the system ground, the resulting magnetic force
overcomes the spring force, fuel pressure and manifold vacuum suction to draw up the valve core.
The fuel sprays from the guide hole through the valve seat hole mistily to the intake valve. When
the power supply is cut off, the magnetic force disappears. Under the spring force and the fuel
pressure, the injector nozzle closes. The top of the fuel injector has the reliable fuel pressure
sealing generated by the rubber seal ring and the fuel rail interface; the lower part also uses the
rubber seal ring and engine air intake manifold to form the air sealing. Fuel injector resistance is
11.4-12.6 Ω.

Note: When the fuel injector is blocked or not closed tightly, the engine malfunction lamp may
be lit, but the detection fault code is: oxygen sensor distortion, erratic signal, abnormal Air-Fuel
ratio and other faults. At this time, the failure component should be carefully judged. Because
when the fuel injector is blocked or leaking, the amount of fuel injected is not controlled by the
ECM pulse width, the mixed air concentration signals of the oxygen sensor feedback to ECM
will be very different from the ECM control target. When ECM detects this signal, it will
determine whether the oxygen sensor is working properly. But the system cannot determine
whether the fault comes from the oxygen sensor itself or other associated malfunction due to
the damage of other parts. Therefore, at the service of such malfunctions, the failed
components must be carefully identified.

9. Fuel Pump Assembly

The fuel pump is turbine single-stage electric fuel pump under the control of the ECM via the fuel
pump relay. It has a check valve at the outlet of the fuel pump. When the engine is not running, the
remaining oil in the pipeline will not quickly return to the fuel tank, so as to ensure the re-starting
performance. Fuel level sensor is a variable sliding resistance type.

10. Ignition Coil

Cylinder 1 and 4 have their ignition coils located at the top of the Cylinder 4’s spark plug opening.
Cylinder 2 and 3 have their ignition coils located at the top of the Cylinder 2ee's spark plug

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2.8.3 System operating principle

2.8.3.1 System operating Principle
Cold Engine: the engine normal operating temperature is generally around 95°C (203 °F), in this

temperature range, all the engine parts running status will be ideal. If the engine can not reach the

ideal operating temperature in a long time,it will increase the parts wear and tear. Because of low

temperature, the mixture combustion will be inadequate, and there will be excessive carbon

residue. The engine heat exchange must be kept minimum so the engine can reach normal working

temperatures in a short period of time. At this point the thermostat controls the engine coolant only

circulates within the engine block, bringing the heat from the cylinder wall to the other engine

parts, so that the temperature increases rapidly. Water pumps makes the engine coolant flow in the

cylinder block, then in the engine block water jacket, throttle body and cylinder hood cover. This

is called "small loop".
Engine at normal working temperature: With the engine running, the engine coolant temperature

quickly increases, when the thermostat reaches 83 (181.4

℃

°F), the engine coolant is drawn into

the engine block water jacket, intake manifolds, cylinder hood and radiator by the water pump.

This is called "big loop".
Thermostat: the thermostat is used to control the flow of engine coolant in the cooling system.

Thermostat is installed in the front of the engine and sealed by the engine intake pipe joints

components, located in the front of the cylinder hood cover. The thermostat can prevent the engine

coolant.
Flow from the engine to the radiator, so as to rapidly pre-heating the engine and adjust the

temperature of engine coolant. When the engine coolant temperature is low, the thermostat in the

closed position, preventing the engine coolant circulating through the radiator. Starting is only

allowed at this time.
Engine coolant is circulated through the heater core to quickly and uniformly preheat the engine.

When the engine is warm, the thermostat opens. The engine coolant flows through radiator and

exchanges the heat. Thermostat opening and closing, allow sufficient engine coolant to enter into

the radiator, maintaining the engine at normal operating temperature range. The wax ball inside

the thermostat is sealed in a metal casing. Thermostat wax ball thermal expands when warm and

contracts when cold. As the vehicle drives and the engine warms up, engine coolant temperature

increases. When the engine coolant reaches the required temperature, the thermostat wax ball

expands, puts pressure on the metal shell and opens the valve. This allows the engine coolant to

flow through the engine cooling system and engine to cool down, when the wax ball contracts,

under the action of the spring, the valve will be closed.

Cooling Fan Low-Speed Circuit Description: Engine cooling fan circuit controls the main cooling

fan and auxiliary cooling fan. Cooling fan is controlled by the engine control module (ECM)

according to the temperature sensor of engine coolant and air pressure switch inputs.
When ECM monitors conditions that meet the cooling fan Low-Speed running conditions, ECM

controls the engine wiring harness connector EM01 terminal No.65 for internal grounding, and the

Low-Speed cooling fan relay pulls in. Power passes through the low speed relay 1 terminal No.87

to reach the cooling fan motor 1 and then through the Fan low-speed relay 2 to reach the fan motor

2 within the series connection. Finally the circuit is grounded via the harness connector CA10

terminal #2 of fan motor 2. For the series connection of the fan motors changes the current

through the motors, the fan motors run at low speed.
Description of high-speed circuit of cooling fan: the engine control module receives the engine

coolant temperature sensor and air-conditioning pressure switch signal; after reaching the

condition that the cooling fan rotates at high speed through the calculation of the internal program,

the ECM controls the terminal 17 of the engine wire harness connector EM01 to internal ground;

at this time, the cooling fan high-speed relay and the low-speed relay 2 are closed; the power

supply of the fan 2 reaches the terminal 1 of the wire harness connector CA10 of the cooling fan 2

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The themostat start to open when the tem-

perature of engine coolant reach to 83℃(181.4ºF), and it fully opened when the temperature at
95℃(1203ºF)

2.12.3 System operating principle

2.12.3.1 Electronic Throttle Body (ETC) Operating Principle

油门踏板位置

传感器总成

发动机

控制模块

电子控制

节气门体总成

NL02-2014b

Electronic throttle body assembly must be used dedicatedly to the engine electronic control
module (ECM) with ETC system-driven feature hardware as the core control element. System
control software usually uses the computer algorithms mode, basing on the engine torque output
control. At the same time, due to the cancellation of the traditional mechanical throttle valve
control of mechanical pull cables, ETC is equipped with a acceleration pedal position sensor (APP)
with a resistive potentiometer device, in order to provide vehicle handling demand information
and other information for the driver to control the vehicle to the engine electronic control module
(ECM).

Electronic throttle body opening is determined by ECM according to the acceleration pedal control
input signals. With other engines and vehicles sensor input signals, ECM analyzes the driver's
intention in advance and calculates the needed engine output power and accordingly adjusts the
engine throttle opening and fuel supply (injection) amount. At the same time, the electronically
controlled throttle position sensor can detect the actual throttle opening and send the feedback to
ECM. ECM then, based on this feedback signal, adjusts the vehicle control parameters. This
control process ensures that the engine and vehicle work in the ideally controlled conditions. Due
to the rapid development of modern science and technology, High-Speed ECM can quickly
analyze the driver's intention and calculate the basic throttle opening parameter values, based on
the throttle pedal signal, the signal variation and signal change rate. At the same time, ECM
adjusts and optimizes the throttle opening parameter, based on various sensors input signal status,
so that the system further calculates the optimum throttle opening control parameters and
implements the actual throttle control. ECM sends the output control signal to the ETC motor
drive circuit to open the throttle according to the calculated opening parameter, based on the
revised throttle opening and pre-determined control strategy. Because of the high speed
calculation, the system enables smooth engine speed changes under transition engine operating
conditions. The whole control process only requires a few milliseconds, achieving excellent
vehicle performance.

The application of automotive electronic technology makes it difficult to directly judge the
electronic drive control throttle valve body assembly diagnosis by conventional visual inspection
method. In the event of electronic controlled throttle body malfunction, the system needs to
provide a Jolt-limited function. It allows the driver to drive the vehicle to a repair station for
repair.

Accelerator

position sensor

assembly

Engine control

module

Electric control

throttle

bodyassembly

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