Geely Emgrand X7. Manual part — 24

2.2.2 Description and Operation

2.2.2.1 Overview

This engine control system uses Delphi MT22.1 Control System. Its main characteristic is that the
engine control module (ECM) acts as the core system. The traditional mechanical throttle pedal
and mechanical throttle body are replaced by more advanced electronic throttle acceleration pedal
sensor assembly and the electronic throttle body assembly. Due to this advanced system, ECM
torque control over the engine is more convenient. In addition, MT22.1 control system also
incorporates multi-point sequential fuel injection, group direct ignition without electricity
distributions, variable valve timing control and three-way catalytic converter post-processing,
capable to meet the increasingly stringent emission regulations.

The system’s main functions include:

1. Engine torque output control mode: ECM calculates the gas flow through the intake air

temperature sensor and intake manifold pressure sensor signals, making the Air-Fuel ratio
closer to the current engine’s operating condition demand.

2. Torque control mode: ECM calculates the current required output torque and controls the

engine output power, according to the acceleration pedal position sensor signal.

3. Main relay control of Complete Vehicle.

4. Close-loop control multi-point sequential fuel injection: A close-loop fuel control can

precisely control the engine air- fuel ratio, and therefore efficiently controls emissions. Close-
loop control can effectively eliminate the system and related mechanical component swear
and tear due to manufacturing error and improves vehicle consistency.

5. Variable Valve Timing (VVT) control: Variable valve timing control system uses VVT

actuator to change the relative positions between intake camshaft and crankshaft. Engine
management system calculates the best valve timing based on engine operating conditions,
and controls VVT solenoid valve movement, allowing flow and direction of oil pressure in
VVT actuator to change, and ultimately promoting the camshaft movement to the desired
position.

6. Fuel supply control without fuel return.

7. Fuel pump working control.

8. ECM has built-in ignition drive module and group direct ignition without electricity

distributions.

9. Knock Control: When the knock sensor detects a knock occurring, the system will calculate

the ignition advance angle delay based on the current conditions, knock intensity and other
necessary information, and defers the ignition advance angle, so as to avoid or reduce knock.
Electronic Throttle Control: Since the system uses an electronic throttle, highly precise idle
control can be achieved. Taking the electrical load compensation as an example, when there
is electrical load or the load is cut off, due to the sudden increase or decrease in engine load
which results in engine speed fluctuation in a certain range, therefore, we add the electrical
load control adjustments. When the load increases or decreases, adjust the air flow rate and
/or the ignition advance angle accordingly to make sure that the idle speed remains steady at
the best condition.

10. Canister Solenoid Valve Control

11. Cooling fan relay control

12. System self-diagnostic function: After the system enters working condition, ECM controls all

system components working, and tests them in real time. Once the system or component
malfunction occurs, the system will light up the engine malfunction lamp to remind the driver
to repair or service the vehicle on time. In the mean time, ECM will start fault protection
mode.

13. System over-voltage protection: When the charging system malfunction causes the voltage

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too high, the system will enter protection mode to restrict the engine speed to prevent ECM
damage.

2.2.2.2 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 is 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

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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
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 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

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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 2’s spark plug opening.
Ignition coil primary winding low voltage will be transformed into the secondary winding high
voltage. The spark plug discharges spark, igniting the air and fuel mixture inside the cylinder.
Ignition occurs when one piston is at the compression TDC and the other is at exhaust TDC. For
the internal air pressure in the cylinder near the exhaust TDC is low but the temperature is high.
Less energy will enable the ignition through electrode puncture at the spark plug with less energy,
known as redundant ignition. While, the cylinder mixture density and pressure is high at the
compression TDC, more ignition energy is required for spark plug ignition making the mixture
quickly ignited for power. Therefore, this cylinder ignition is called the effective ignition.

11. Electronic

Throttle

Body

(ETC)

The electronic throttle valve assembly opening is determined by ECM according to the
driver-controlled throttle pedal control input signals, and other input signals after calculating the
vehicle currently needed engine output power to control the fuel supply (spray) amount, and then
adjusting the control parameters based on feedback signals to make sure that the engine works
under the best controlled status. Electronic throttle valve body adds the drive motor, gear drive
mechanism and other components, as well as a throttle position sensor with enhanced functionality
and reliability.

12. Canister Solenoid Valve (EVAP)

The canister control valve is located at the side of the engine cylinder head (transmission side) and
is used to control the canister purge flow. ECM controls intake manifold gasoline vapor volume
through canister solenoid valve. ECM sends square pulse wave. Air flow volume and control pulse
square wave relationship is linear.

ECM changes canister working time and rate according to engine speed and load conditions.

Solenoid valve coil resistance: 11 - 22 Ω.

13. Variable Valve Timing Solenoid Valve (VVT)

VVT solenoid valve is located at the intake manifold side near the engine front. VVT magnetic
valve is a 4-digit 4-channel solenoid valve with the working power supplied from main relay
controlled by ECM. ECM controls VVT solenoid valve grounding with a pulse width modulation
signal. The crankshaft to the camshaft timing relations can be continuously changed. The best
valve timing control can be achieved at different engine running conditions. This will help to
increase engine efficiency, improve idle stability, and provide more torque and power, while
helping to improve the fuel economy and lower emissions of hydrocarbons and nitrogen oxides.

Solenoid valve resistance: 7.2 Ω at 20°C (68℉)

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