2012 SSANGYONG RODIUS fuel

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Fuel Temperature
SensorCoolant Temperature Sensor
Knock Sensor (2)T-MAP SensorD20DTR ECU

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Fuel rail pressure Water sensor
(2) Components for ECU Input
CAN
- ABS & ESP
- GCU
- Indicator/
Warning Lamp,
Meter Cluster
- TCUSwirl valve
position
sensor
Differential
pressure sensorE-EGR valve
position
sensorCamshaft position
sensorCoolant
temperature
sensor
EGT sensorHFM sensorOxygen sensorT-MAP sensor
Crankshaft
position
sensorAccelerator pedal
sensorThrottle
position
sensorKnock sensor
- Auto cruise switch
- Refrigerant pressure
sensor
- Blower switch signal
- Brake pedal signal

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2) ECU Control
(1) Function
a. ECU Function
ECU receives and analyzes signals from various sensors and then modifies those signals into
permissible voltage levels and analyzes to control respective actuators.
ECU microprocessor calculates injection period and injection timing proper for engine piston speed and
crankshaft angle based on input data and stored specific map to control the engine power and emission
gas.
Output signal of the ECU microprocessor drives pressure control valve to control the rail pressure and
activates injector solenoid valve to control the fuel injection period and injection timing; so controls
various actuators in response to engine changes. Auxiliary function of ECU has adopted to reduce
emission gas, improve fuel economy and enhance safety, comforts and conveniences. For example,
there are EGR, booster pressure control, autocruise (export only) and immobilizer and adopted CAN
communication to exchange data among electrical systems (automatic T/M and brake system) in the
vehicle fluently. And Scanner can be used to diagnose vehicle status and defectives.
<00760097008c00990088009b00900095008e0047009b008c00940097008c00990088009b009c0099008c0047009900880095008e008c00470096008d0047006c006a007c00470090009a0047009500960099009400880093009300a000470054005b005700
47009b009600470052005f005c00b6006a004700880095008b> protected from factors like oil,
water and electromagnetism and there should be no mechanical shocks.
To control the fuel volume precisely under repeated injections, high current should be applied instantly
so there is injector drive circuit in the ECU to generate necessary current during injector drive stages.
Current control circuit divides current applying time (injection time) into full-in-current-phase and hold-
current-phase and then the injectors should work very correctly under every working condition.
b. Control Function
Controls by operating stages
To make optimum combustion under every operating stage, ECU should calculate proper injection
volume in each stage by considering various factors.
Starting injection volume control
During initial starting, injecting fuel volume will be calculated by function of temperature and engine
cranking speed. Starting injection continues from when the ignition switch is turned to ignition
position to till the engine reaches to allowable minimum speed.
Driving mode control
If the vehicle runs normally, fuel injection volume will be calculated by accelerator pedal travel and
engine rpm and the drive map will be used to match the drivers inputs with optimum engine power. -
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(2) Fuel injection control
a. Multi injection
Fuel injection process consists of 3 steps: Main Injection, Pilot Injection, Post Injection
This is the injection before main injection. This consists of 1st and 2nd pilot injection, and Pre-injection.
The steps are normally used to control the NOx, noise, idle stability and engine vibration. Inject a small
amount of fuel before main injection prevents the instant high combustion temperature. It reduces the
NOx and decreases the engine noise and vibration. The main injection produces the actual output. The
vehicle output is based on the main injection. The post injection is the injection process after main
injection and consists of ‘After injection”, “Post 1 injection” and “Post 2 injection”. All of post
injections are to reduce the PM and harmful exhaust gas. The post injection does not make the actual
output. The post injection activates the fuel by injecting the fuel to the incompletely combusted gas after
primary combustion. Through the process, the PM and smoke in the exhaust gas could be reduced.
There are totally 7 injections as shown in the figure. However, all of 7 injections are not performed during
driving because it decreases the fuel economy. Totally 5 injections can be performed in one cycle.
InjectionFunction
MainProduces engine power
Pilot 1Reduces PM by injecting before
main injection.AfterPM control
Pilot 2Reduces NOx and noise by
shortening main injection delay
due to flammability Post 1Reduces PM by enabling fuel
activation.
PreControls NOx emission level,
Combustion noise and
Stable idle Post 2Activates CDPF by increasing
exhaust gas temperature and
supplying reduction material

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b. Pilot Injection
Injection before main injection. Consists of 1st and 2nd pilot injection, and Pre-injection
Inject a small amount of fuel before main injection to make the combustion smooth. Also, called as
preliminary injection or ignition injection. This helps to reduce Nox, engine noise and vibration, and to
stabilize the idling.
The injected fuel volume is changed and stopped according to the coolant temperature and intake air
volume.
Pilot injection is much earlier than main injection due to higher engine rpm
Too small injection volume (insufficient injection pressure, insufficient fuel injection volume in main
injection, engine braking)
System failure (fuel system, engine control system) -
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Pilot injection
Main injection
Combustion pressure with pilot injection
Combustion pressure without pilot injection 1.
2.
1a.
2b. Stop conditions
Combustion pressure characteristic curve for pilot injection ▶

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c. Main Injection
The power of the vehicle is determined by the main fuel injection volume.
Main injection calculates the fuel volume based on pilot injection. The calculation uses the value for
accelerator pedal position, engine rpm, coolant temperature, intake air temperature, boost pressure,
boost temperature and atmospheric pressure etc.
d. Post Injection
Injection after main injection. Consists of After injection, Post 1, Post 2 injection.
Post injection reduces PM and smoke from exhaust gas. No actual output is generated during these
injections, instead, fuel is injected to the unburned gas after main injection to enable fuel activation.

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(3) Fuel Pressure Control
Fuel pressure is controlled by IMV opening according to the calculated value by ECU.
Pressure in the fuel rail is determined according to engine speed and load on the engine. ▶
When engine speed and load are high
The degree of turbulence is very great and the fuel can be injected at very high pressure in order to
optimize combustion.
When engine speed and load are low
The degree of turbulence is low. If injection pressure is too high, the nozzle's penetration will be
excessive and part of the fuel will be sprayed directly onto the sides of the cylinder, causing
incomplete combustion. So there occurs smoke and damages engine durability. -
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Fuel pressure is corrected according to air temperature, coolant temperature and atmospheric pressure
and to take account of the added ignition time caused by cold running or by high altitude driving. A
special pressure demand is necessary in order to obtain the additional flow required during starts. This
demand is determined according to injected fuel and coolant temperature.
Open loop determines the current which needs to be sent to the actuator in order to obtain the
flow demanded by the ECU. ▶
Closed loop will correct the current value depending on the difference between the pressure
demand and the pressure measured. ▶
If the pressure is lower than the demand, current is reduced so that the fuel sent to the high pressure
pump is increased.
If the pressure is higher than the demand, current is increased so that the fuel sent to the high
pressure pump is reduced. -
-Fuel Pressure ▶

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A fourth correction is made according to the pressure error.
This correction is used to reduce the injection timing advance when the pressure in the rail is higher
than the pressure demand.
A fifth correction is made according to the rate of EGR.
This correction is used to correct the injection timing advance as a function of the rate of exhaust gas
recirculation. -
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When the EGR rate increases, the injection timing advance must in fact be increased in order to
compensate for the fall in termperature in the cylinder.
A. Main Flow Control
The main flow represents the amount of fuel injected into the cylinder during the main injection. The pilot
flow represents the amount of fuel injected during the pilot injection.
The total fuel injected during 1 cycle (main flow + pilot flow) is determined in the following manner.
When the driver depress the pedal, it is his demand which is taken into account by the system in order
to determine the fuel injected.
When the driver release the pedal, the idle speed controller takes over to determine the minimum fuel
which must be injected into the cylinder to prevent the enigne from stalling. -
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The driver demand is the translation of the pedal position into the fuel demand. It is calculated as a
function of the pedal position and of the engine speed. The driver demand is filtered in order to limit the
hesitations caused by rapid changes of the pedal position. A mapping determines the maximum fuel
which can be injected as a function of the driver demand and the rail pressure. Since the flow is
proportional to the injection time and to the square root of the injection pressure, it is necessary to limit
the flow according to the pressure in order to avoid extending the injection for too long into the engine
cycle. The system compares the driver demand with this limit and chooses the smaller of the 2 values.
The driver demand is then corrected according to the coolant temperature. This correction is added to
the driver demand.
(5) Fuel Control
B. Driver Demand