2. OPERATING PROCESS
1) System Layout
(1) Engine start
SKM performs the authentication process for the SMART key and sends the engine start request to
EMS if there is a normally coded SMART key when pressing the Engine Start/Stop button with the
SKM sends the start request signal to PCAN network and the cranking request to BCAN network by
button.
SKM turns off the IGN2/ACC relay during cranking to shut down the electric loads.
SKM receives the starting status signal from EMS throug PCAN.
EMS starts to crank the engine after checking the pre-heating condition if it receives the engine
cranking request 1 when pressing the Engine Start/Stop button. EMS starts to crank the engine
immediately if it receives the engine cranking request 2 when pressing the Engine Start/Stop button. 1.
2.
3.
4.
5.
6.
Engine cranking request 1: when pressing the Engine Start/Stop button shortly in normal
conditions
Engine cranking request 2: when pressing the Engine Start/Stop button again after first press or
when pressing the Engine Start/Stp button for more than 3 seconds -
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Engine start during driving 7.
When pressing the Engine Start/Stop button with IGN ON, the engine start is requested if the
the brake switch is ON (no need authentication for 30 seconds).
When pressing the Engine Start/Stop button with IGN ON, the engine start is requested
position (no need authentication for 30 seconds).
Except input of brake switch signal
In vehicle equipped with A/T, when pressing the Engine Start/Stop button for more than 10
seconds with ACC ON, the engine start is requested regardless of brake signal if the gear shift
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3) Decelerating with the Cruise Control System
(1) While the cruise control system is running
Push down the DECEL switch of the cruise control lever and hold it until the desired speed is reached
without a brake pedal intervention. But the cruise control system cannot maintain the cruise function at
less than 38 km/h.
When the desired speed is reached, release the lever. 1.
2.
(2) When the cruise control system is not running
Push down the DECEL switch of the cruise control lever and hold it.
And then release the accelerator pedal slowly.
When the desired speed is reached, release the lever. But the cruise control system cannot maintain
the cruise function at less than 38 km/h.1.
2.
3.
4.
(3) Tap-down while the cruise control system is running
Push down the DECEL switch of the cruise control lever less than 0.5 second per one switching while
the cruise control system is running. This is a tap-down switching.
When you operate a tap-down switching, the vehicle is decelerated by 1 km/h below the previous set
speed.
If you want to decelerate to 10 km/h, operate the tap-down switching ten times without the brake
pedal intervention. 1.
2.
3.
6) Normal Cancellation of the Cruise Control
The cruise control system will be canceled when one or more items of the following conditions are
applied;
When the brake pedal is depressed.
When the cruising speed is decreased less than 38 km/h.
When pushing the ON-OFF switch of the cruise control lever.
When ESP is activated.
When applying the parking brake while driving.
When using the clutch in order to shift (M/T only).
To cancel the cruise control function, pull the cruise switch toward you. (GSL only). 1.
2.
3.
4.
5.
6.
7.
Keep the main cruise control switch in the neutral position when not using the cruise control.
And the cruise control system can be operated again in driving state.
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Abnormal changes of the gear selector lever can damage the yyengine. Do not move the gear shift
lever to Neutral while driving at the set speed. Automatic transaxle damage may result.
The speed that has been set may not be maintained on uphill or yydownhill slopes.
The speed may drop to less than the set speed on a steep uphill yygrade. The accelerator must be
used if you want to maintain that speed.
The speed may increase to more than the set speed on a steep yydownhill grade. When the speed
increases too much, turn off the cruise control. 1.
2.
3.
4.
(1) Abnormal Cancellation of the Cruise Control
When the rapid deceleration is applied without braking.
When the rapid acceleration is applied without acceleration pedal intervention (DSL only).
When the cruise control lever is failed (DSL only).
When the brake switch and the brake light switch input signal are implausible. 1.
2.
3.
4.
And the cruise control system cannot be operated again in driving state. In this case, you should stop the
vehicle, and turn off the ignition switch and then turn it on again. After you do that, you can use the cruise
Ssangyong Dealer for diagnosis of the cruise control system.
(2) Using the Cruise Control on Hills
How well the cruise control works on hills depends on the speed, load, and the steepness of the hill.
When going up steep hills, you may have to depress the accelerator pedal to maintain your speed.
When going downhill, you may have to brake or shift to a lower gear to keep your speed down.
Applying the brake takes you out of the cruise control.
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1. ENGINE DATA LIST
Data Unit Value
Coolant temperature
Intake air temperature
temperature or engine mode)
Idle speed rpmA/T
M/T
Engine load % 18~25%
Mass air flow kg/h 16 to 25 kg/h
Throttle position angle
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 04. 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 mV 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 -
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Oil pressure
switch
Fuel rail
pres.sensor
Differential
pressure
sensor
Swirl valve posi.
sensor
Meter cluster
Coolant temp.
sensorE-EGR valve
posi. sensor
Oxygen
sensor
Exhaust gas
temp. sensor
HFM sensor
(2) Components for ECU Input
Crankshaft posi.
sensorAccel. pedal
posi. sensorThrottle
posi.sensor
Knock sensor
T-MAP sensor
Camshaft posi.
sensor
CAN
- ABS&ESP
- GCU
- Meter cluster
- TCU
- BCM
- Refrigerant pressure sensor
- Clutch pedal signal
- 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.
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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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. -
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d. Fuel Control
1. 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.
It is therefore the greater of these 2 values which is retained by the system. This value is then compared
with the lower flow limit determined by the ESP system.
As soon as the injected fuel becomes lower than the flow limit determined by the ESP system, the
antagonistic torque (engine brake) transmitted to the drive wheels exceeds the adherence capacity of
the vehicle and there is therefore a risk of the drive wheels locking.
The system thus chooses the greater of these 2 values (main flow & pilot flow) in order to prevent any
loss of control of the vehicle during a sharp deceleration.
As soon as the injected fuel becomes higher than the fuel limit determined by the ASR trajectory control
system, the engine torque transmitted to the wheels exceeds the adhesion capacity of the vehicle and
there is a risk of the drive wheels skidding. The system therefore chooses the smaller of the two values
in order to avoid any loss of control of the vehicle during accelerations.
The anti-oscillation strategy makes it possible to compensate for fluctuations in engine speed during
transient conditions. This strategy leads to a fuel correction which is added to the total fuel of each
cylinder.
The main fuel is obtained by subtracting the pilot injection fuel from the total fuel.
A mapping determines the minimum fuel which can control an injector as a function of the rail pressure.
As soon as the main fuel falls below this value, the fuel demand changes to 0 because in any case the
injector is not capable of injecting the quantity demand. A switch makes it possible to change over from the supercharge fuel to the total fuel according to the
state of the engine.
Until the stating phase has finished, the system uses the supercharged fuel.
Once the engine changes to normal operation, the system uses the total fuel. -
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