Geely EC718, EC718RV, EC715, EC715RV. Manual part — 168

2.12.2 Description and Operation
2.12.2.1 Overview

4G15D uses Delphi MT80 Engine Control System. Its main
characteristic is that the engine control module (ECM) is 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 adopt this system,
ECM control over the engine torque is more convenient. In
addition, MT80 control system also incorporates multi-point
sequential fuel injection, group direct ignition without electricity
distributions, variable valve timing control and three-way
catalytic converter processing, to meet the increasingly
stringent emission regulations.

System main functions includes:

1. Engine torque output control mode: ECM calculated the gas

flow through the intake air temperature sensor and intake
manifold pressure sensor signals, so that the Air-Fuel ratio
is closer to the current engine operating conditions
demand.

2. Torque control mode: ECM calculates the output torque

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

3. Main relay control.

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

close-loop fuel control can precisely control the engine Air-
Fuel ratio, therefore efficiently controls emissions. Close-
loop control can effectively eliminate the system and related
mechanical components wear 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 intake
camshaft and the crankshaft relative positions. Engine
power management system calculates the best valve
timing based on engine operating conditions, and controls
VVT solenoid valve movement, allowing oil pressure, flow
and direction to change, and ultimately promoting the
camshaft movement to the desired position.

6. Fuel control without fuel return.

7. Fuel pump control.

8. ECM has built-in ignition drive module, without electricity

distinction group direct ignition.

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 idle speed control, highly precise idle control can be
achieved. Such as the electrical load compensation, when
there are electrical loads or the load is cut off, due to a
sudden increase or decrease in engine load, resulting in
engine speed fluctuation in a certain range, this increases
the electrical load control adjustments. When the load
increases or decreases, the air flow rate and (or) the ignition
advance angle will be adjusted accordingly, so that the idle
speed remains steady.

10. Canister solenoid valve control

11. Cooling fan relay control

12. System self-diagnostic function: After the system enters

into 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 voltage over load protection: When the charging

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

2.12.2.2 Components Descriptions

1. Engine Control Module (ECM)

FE02-8031b

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Engine control module is a core microprocessor with a a micro
chip controller. Its function is to process data from various
vehicle sensors to determine the engine's working condition,
and through the various actuators controls engine actuators.
ECM normal working voltage is 9.0 V-16 V

Note

Although ECM has the voltage over load 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 15V.
Otherwise, it will cause damage to ECM and other
electrical equipments.

2. Crankshaft Position Sensor (CKP)

FE02-5121b

The crankshaft position sensor output can be used to
determine crankshaft position and rotation speed. Crankshaft
position sensor is a magnetic-electric sensor, which is installed
in the front end of the transmission housing, and tightened with
bolts, below the coolant temperature sensor. Flywheel signal
plate and the crankshaft sensor is an integrated part. The
sensor and the signal plate tooth gap in between 0.3 and 1.5
mm (0.01-0.06 in). The signal plate has 58 machined slots.
When the crankshaft rotates, 58X tooth tip and the alveolar
passes through the sensor from different distances. 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.
Sensor Resistance: 500 Ω-610 Ω
Output Voltage: 400 mV when 60 rpm. The voltage increases
as the speed increases.

3. Intake Manifold Pressure / Temperature Sensor
(MAP / IAT)

FE02-8032b

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 resulting 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 is low. MAP sensor is also used
to measure atmospheric pressure. This measurement is
calculated as part of the MAP calculation. When the ignition
switch is turned on and the engine is not running, the engine
control module reads atmospheric pressure as the intake
manifold pressure, and adjusts the Air-Fuel ratio accordingly.
With this kind of altitude compensation, the system can
maintain a low emissions while maintaining maneuverability.
Sensor signal passes through ECM harness connector EN01
terminal No.19 to ECM. When MAP sensor and its circuit
malfunction occurs, DTC P0105, P0106, P0107, P0108 will be
recorded.

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4. Camshaft Position Sensor (CMP)

FE02-5362b

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 location. ECM measures
digital voltage signal through the sensor, therefore determining
the working cylinder and to implement 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 fuel injection order based on the final fuel injection
pulse, while the engine continues to run. If the engine starts
after being shut down, the fuel injection will be converted from
sequential injection to group injection. Even if the fault exists,
the engine can be restarted.

5. Engine Coolant Temperature Sensor (ECT)

FE02-5127b

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 thermistor as the sensing
element, when the coolant temperature rises, the resistance
decreases. At -30 ° C (-22 ° F) the resistance is 26000 Ω; at
130 ° C (266 ° F), the resistance is 90 Ω. The sensors is
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) through the CAN network, used to display
the current engine working temperature.

6. Knock Sensor (KS)

FE02-5125b

Knock sensor is a frequency response sensor, installed in the
engine block the most sensitive to knocking part, the lower
intake manifold. ECM uses knock sensor to detect knock
intensity, and then 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 the signal, filter out the non-knock signals and
determine engine cycle calculated by camshaft and crankshaft
position sensor signals. ECM determines the cylinder in which
the knock occurs and will delay the ignition advance angle for
this cylinder until the knock 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 wire has a shielded
cable. Its resistance is 1M Ω, in any case the output signal is
greater than 17mV / g

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7. Oxygen Sensor (HO2S)

FE02-5129b

Oxygen sensor is an important sensor 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 mixture Air-Fuel ratio
becomes lean, the oxygen content in the exhaust increases,
and oxygen sensor output voltage is reduced. On the contrary,
the output voltage increase feedback to ECM indicates the air-
fuel ratio.
Oxygen sensor sensing material is zirconia, hollow with an
external sensing part. When Zirconia components are heated,
they are activated, reference air enters the hollow parts of
zirconium oxide from the wire. Exhaust passes through the
outer electrode, oxygen ions move from the center of zirconia
to the outer electrode, thus consisting a simple atomic battery
with a voltage between two electrodes. According to the
oxygen concentration in the exhaust, Zirconium oxide changes
the output voltage, and thus determining the oxygen content in
the exhaust. Usually the exhaust oxygen sensor design
generates a voltage amplitude jump in the vicinity of the Air-
Fuel ratio (14.6:1) to help ECM to determine the exact Air-Fuel
ratio. Pre-Catalytic oxygen sensor is installed in the exhaust
manifold, the three-way catalytic converter front end. Post-
Catalytic oxygen sensor is installed in the three-way catalytic
converter rear end. When the mixture is rich, the output voltage
is 750 mV. When the mixture is lean, the output voltage is less
than 200 mV. When the mixture becomes rich from lean, the
responding time is less than 75 ms. When the mixture becomes
lean from rich, the responding time is less than 150 ms.

8. Fuel Injectors

FE02-5131b

The injector structure is an electromagnetic switch valve
device. The coil form poles leads to the engine wiring harness
and ECM and is connected to power supply. 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, and draws the valve
core. The fuel sprays through the valve seat hole to the guide
hole as a mist type spraying into the intake valve. When the
power supply is cut off, the magnetic force disappears, with the
spring force and fuel pressure, the injector closes.
The top of the fuel injector rubber seal and the fuel rail form a
reliable fuel pressure seal; the lower part of the same rubber
seal and the engine air intake manifold form an air seal. Fuel
injector resistance is 11.6-12.4 Ω.

Note

When the fuel injector is blocked or not closed tight, the
engine malfunction lamp may be lit, but the detection of
DTC code is: oxygen sensor distortion, erratic signal,
such as Air-Fuel ratio is not normal fault. At this time
component malfunction 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 control. The oxygen sensor feedback to ECM will
be very different from the ECM control target. When ECM
detects this signal, it will determine the oxygen sensor is
not working properly. But the system can not determine
whether the fault is the oxygen sensor itself or other
associated parts. Therefore when diagnose such a
malfunction, the malfunction component must be
carefully identified.

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