06-211914-01
Control
rangeTurbocharger
driving
mechanismControl
methodEffectImproved
performance
At low
speedNarrows the
flow passage fo
r
the exhaust gas
by folding the
vanesThe flow rate is
increased as the
exhaust gas passes
the narrow passage
→ Increased
turbine & impeller
speed, Increased
compressive forceImproved
low speed torque
4. OPERATING PRINCIPLES
The E-VGT is designed to get more improved engine power in all ranges by controlling the turbine as
follows:
1) How it Works at Low Speed
Normal turbocharger cannot get the turbo effect because the amount of exhaust gas is not enough
and the flow speed is slow in a low speed zone, but VGT allows the flow passage of exhaust to narrow,
resulting in increasing the flow speed of exhaust gas and running the turbine quickly and powerfully.
Therefore, as VGT can intake more air than normal turbocharger, it can give the benefit of the
increased output even in a low speed zone.
Turbocharger lag
The turbocharger is at idle speed when there is no load or it is in the normal driving condition. During
this period, the amount of exhaust gas passing through the turbine is not enough to turn the
compressor wheel (impeller) fast. Therefore, the intake air is not compressed as needed. Because
of this, it takes time for turbocharger to supply the additional power after the accelerator pedal is
depressed. This is called "turbocharger lag".Basic principle at low speed
At low speed, it utilizes the principle of venturi.
For example, when air flows through the venturi
tube, the flow speed is faster and the pressure
is lower at the point "A". In this case, if the inner
diameter of venturi is more narrowed, the flow
speed is so much faster (refer to the equation). ※
10-4
1. OVERVIEW
The pre-heating system for D20DTR engine has the glow plug to the cylinder head (combustion
chamber), and improves the cold start performance and reduces the emission level.
The pre-heating resistor (air heater) is used to heat the intake air.
This enables the diesel fuel to be ignited in low temperature condition.
The ECU receives the information such as, engine rpm, coolant temperature, engine torque, etc.,
through CAN communication during pre-heating process; and the pre-heating control unit controls the
pre-heating, heating during cranking and post-heating by the PWM control.
Glow plug
Engine ECU (D20DTR)Glow indicator
Glow plug control unit
(GCU)
13-71793-00
2) Input/Output Devices
3) Control Logic
The EGR system controls the EGR amount based on the map values shown below:
Main map value: Intake air volume
Auxiliary map value: ※
※
Compensation by the coolant temperature
Compensation by the atmospheric pressure: Altitude compensation
Compensation by the boost pressure deviation (the difference between the requested value and
the measured value of boost pressure)
Compensation by the engine load: During sudden acceleration
Compensation by the intake air temperature -
-
-
-
-
The engine ECU calculates the EGR amount by adding main map value (intake air volume) and
auxiliary map value and directly drives the solenoid valve in the E-EGR to regulate the opening extent
of the EGR valve and sends the feedback to the potentiometer.
(1) Operating conditions
Intake air temperature: between -10 and 50℃
Atmospheric pressure: 0.92 bar or more
Engine coolant temperature: between 0 and 100°C
When there is no fault code related to EGR -
-
-
-
(2) Shut off conditions
Abrupt acceleration: with engine speed of 2600 rpm or more
When the engine is idling for more than 1 minute
Vehicle speed: 100 km/h or more
Engine torque: 380 Nm or more -
-
-
-
14-6
Overload of CDPF
(warning lamp blinking)Excessive overload of CDPF
(warning lamp illuminated)
5) Warning Lamp Related to CDPF
CDPF regeneration process (warning lamp NOT illuminated) ▶
The CDPF system enters the regeneration mode
when the driving distance becomes approx. 600 to
1,200 km (may differ by the driving condition and
driving style). Then, the engine ECU performs the
CDPF regeneration operation. However, the driver
is not informed with this operation by any engine
warning lamp or vehicle signal, so he/she may not
detect this operation. The control logic at the post-
injection dur-ing the regeneration process is to
increase the fuel injection volume and control the
intake air volume (by the throttle body) in order to
increase the temperature of the exhaust gas. The
driver may not feel any particular difference from
the vehicle.
If the CDPF cannot reach the regeneration
temperature due to low speed driving or other
reason during the regeneration process, the soot is
continuously accumulated in the CDPF. W hen this
condition continues and the CDPF is overloaded
with soot, the engine warning lamp blinks to inform
this situation to the driver.
In order to solve this problem, drive the vehicle at a
speed of approx. 80 km/h for 15 to 20 minutes to
perform the CDPF regeneration process.
If the engine warning lamp on the instrument
cluster blinks, the CDPF is overloaded. In this
case, perform the step 2. 1.
2.
3.If the vehicle is driven at a speed of 5 to 10 km/h
for an extended period of time, the soot
accumulated in the CDPF cannot be burned as the
CDPF cannot reach the regeneration temperature.
Then, an excessive amount of soot can be
accumulated in the CDPF.
This case is much worse than the simple over-load
of the CDPF. To inform this to the driver, the
engine warning lamp comes on and the engine
power is decreased to protect the system.
To solve this problem, blow soot between the
engine and exhaust system several times and
erase the related DTC. Then, check if the same
DTC is regenerated again. If so, check the DTC
related to the differential pressure sensor. 1.
2.
3.
OFF
Blinking Illuminating
Blinking Illuminating
15-30000-00
1. ENGINE DATA LIST
Data Unit Value
Coolant temperature℃ 130℃~-40℃
Intake air temperature℃ -40 to 130℃ (varies by ambient air
temperature or engine mode)
Idle speed rpm 750 ± 50 (P/N)
Engine load % 18~25%
Mass air flow kg/h 16 to 25 kg/h
Throttle position angle°TA 0° (Full Open) to 78° (Close)
Engine torque Nm varies by engine conditions
Injection time ms 3 to 5ms
Battery voltage V 13.5 V to 14.1 V
Accelerator pedal position 1 V 0.4. to 4.8V
Accelerator pedal position 2 V 0.2 to 2.4 V
Throttle position 1 V 0.3 to 4.6 V
Throttle position 2 V 0.3 to 4.6 V
Oxygen sensor V 0 to 5 V
A/C compressor switch
1=ON / 0=OFF -
Full load 1=ON / 0=OFF -
Gear selection (A/T) 1=ON / 0=OFF -
Knocking control 1=ON / 0=OFF -
Brake switch 1=ON / 0=OFF -
Cruise control 1=ON / 0=OFF -
15-130000-00
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) -
-
-
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 ▶
15-16
Pilot injection timing control ▶
The pilot injection timing is determined as a function of the engine speed and of the total flow.
The elements are:
A first correction is made according to the air and coolant temperatures. This correction allows the
pilot injection timing to be adapted to the operating temperature of the engine.
A second correction is made according to the atmospheric pressure. This correction is used to
adapt the pilot injection timing as a function of the atmospheric pressure and therefore the altitude. -
-
(4) Injection Timing Control
Injection timing is determined by the conditions below. ▶
Coolant temperature
Hot engine - Retarded to reduce Nox
Cold engine - Advanced to optimize the combustion 1.
Atmospheric pressure
Advanced according to the altitude 2.
Warming up
Advanced during warming up in cold engine 3.
Rail pressure
Retarded to prevent knocking when the rail pressure is high 4.
EEGR ratio
Advanced to decrease the cylinder temperature when EGR ratio increases 5.
Main injection timing control ▶
The pulse necessary for the main injection is determined as a function of the engine speed and of the
injected flow.
The elements are:
A first correction is made according to the air and coolant temperatures.
This correction makes it possible to adapt the timing to the operating temperature of the engine.
When the engine is warm, the timing can be retarded to reduce the combustion temperature and
polluting emissions (NOx). When the engine is cold, the timing advance must be sufficient to allow
the combustion to begin correctly.
A second correction is made according to the atmospheric pressure.
This correction is used to adapt the timing advance as a function of the atmospheric pressure and
therefore the altitude.
A third correction is made according to the coolant temperature and the time which has passed
since starting.
This correction allows the injection timing advance to be increased while the engine is warming up
(initial 30 seconds). The purpose of this correction is to reduce the misfiring and instabilities which
are liable to occur after a cold start. -
-
-
15-18
C. Idle Speed Controller
The idle speed controller consists of 2 principal modules:
The first module determines the required idle speed according to:
* The operating conditions of the engine (coolant temperature, gear engaged)
* Any activation of the electrical consumers (power steering, air conditioning, others)
* The battery voltage
* The presence of any faults liable to interface with the rail pressure control or the injection control.
In this case, increase the idle speed to prevent the engine from stalling.
The second module is responsible for providing closed loop control of the engine's idle speed by
adapting the minimum fuel according to the difference between the required idle speed and the
engine speed. -
-
D. Flow Limitation
The flow limitation strategy is based on the following strategies:
The flow limitation depending on the filling of the engine with air is determined according to the
engine speed and the air flow. This limitation allows smoke emissions to be reduced during
stabilized running.
The flow limitation depending on the atmospheric pressure is determined according to the
engine speed and the atmospheric pressure. It allows smoke emissions to be reduced when
driving at altitude.
The full load flow curve is determined according to the gear engaged and the engine speed. It
allows the maximum torque delivered by the engine to be limited.
A performance limitation is introduced if faults liable to upset the rail pressure control or the
injection control are detected by the system. In this case, and depending on the gravity of the
fault, the system activates: -
-
-
-
Reduced fuel logic 1: Guarantees 75 % of the performance without limiting the engine speed.
Reduced fuel logic 2: Guarantees 50 % of the performance with the engine speed limited to
3,000 rpm.
Reduce fuel logic 3: Limits the engine speed to 2,000 rpm.
The system chooses the lowest of all values.
A correction depending on the coolant temperature is added to the flow limitation. This correction
makes it possible to reduce the mechanical stresses while the engine is warming up.
The correction is determined according to the coolant temperature, the engine speed and the time
which has passed since starting.
E. Superchager Flow Demand
The supercharge flow is calculated according to the engine speed and the coolant temperature. A
correction depending on the air temperature and the atmospheric pressure is made in order to
increase the supercharge flow during cold starts. It is possible to alter the supercharge flow value by
adding a flow offset with the aid of the diagnostic tool