Page 418 of 600

Do not move the shift lever to Neutral position while driving with the cruise control turned on.
Otherwise, it may result in system malfunction or accidents.
Always be prepared to use the brake or accelerator pedal for safe driving while the cruise control
system is running.
The actual speed can be different from the set speed momentarily when driving on a uphill or
downhill. So, it is recommended to disable the cruise control function on a uphill or downhill. hen
driving on a steep hill use the engine brake and foot brake properly to protect the vehicle system
and for a safe driving.
Ensure that the safe distance is maintained and use the brake pedal if needed. 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.
When the cruise control lever is faulty.
When the brake switch and the brake light switch input signal are implausible. 1.
2.
3.
When the cruise control function is cancelled abnormally or intermittent problems occur, stop the vehicle
and turn off the ignition switch and remove the key to reset the system. After a while, turn on the ignition
switch again to operate the cruise control system.
Page 458 of 600

MDP (Minimum Drive Pulse ) refers to the
minimum power supply pulse for injection which
the injector can perform. It is possible to control
the fuel volume for each injector accurately
through correct learning for the MDP value. The
basic process of MDP learning is that the pulse
slightly higher than MDP is supplied and then (b)
the vibration generated from the cylinder is
detected. The knock sensor detects the vibration
from the engine after a small volume of fuel is
injected. And the time interval between the points
of injection and vibration is measured so that
MDP can be learned. MDP learning is helpful to
prevent engine vibration, high emission and
power reduction through performing calibration
for the old injectors. During MDP learning, a little
vibration and noise can be occur for a while. This
is because the fuel pressure is increased
instantaneously and the exact injection value is
not input, so that the exact engine vibration
timing can be detected.
(6) MDP Learning Control
A. MDP Learning
When the pulse value that the injector starts injection is measured, it is called minimum drive pulse
(MDP). Through MDP controls, can correct pilot injections effectively. Pilot injection volume is very small,
1 to 2 mm/str, so precise control of the injector can be difficult if it gets old. So there needs MDP learning
to control the very small volume precisely through learning according to getting older injectors.
Control the fuel injection volume precisely by MDP learning even for the old injector.
ECU corrects the pilot injection effectively by MDP control.
MDP learning is performed by the signal from knock sensor. -
-
- The system measures the pulse at initial injection to reduce the engine vibration.
B. Purpose of MDP learning
Page 465 of 600

0000-00
LoadEngine speed Swirl valveAmount of
swirlRemarks
Low speed,
Low loadbelow 3,000 rpm
Closed HeavyIncreased EGR ratio, better air-fuel
mixture (reduce exhaust gas)
High speed,
High loadover 3,000 rpm
Open LightIncrease charge efficiency, higher
engine power
The variable swirl valve actuator operates when
turning the ignition switch ON/OFF position to
open/close the swirl valve. In this period, the soot
will be removed and the learning for swirl valve
position is performed.
Swirl: This is the twisted (radial) air flow along the cylinder wall during the intake stroke. This
stabilizes the combustion even in lean air-fuel mixture condition.
Swirl valve
E. Features
Swirl and air intake efficiency
To generate the swirl, the intake port should be serpentine design. This makes the resistance in air
flow. The resistance in air flow in engine high speed decreases the intake efficiency. Eventually, the
engine power is also decreased, Thus, the swirl operation is deactivated in high speed range to
increase the intake efficiency.
Relationship between swirl and EGR
To reduce Nox, it is essential to increase EGR ratio. However, if EGR ratio is too high, the PM also
could be very higher. And, the exhaust gas should be evenly mixed with newly aspired air. Otherwise,
PM and CO are dramatically increased in highly concentrated exhaust gas range and EGR ratio
could not be increased beyond a certain limit. If the swirl valve operates in this moment, the limit of
EGR ratio will be higher. -
-
F. Relationship between swirl and fuel injection pressure
The injector for DI engine uses the multi hole design. For this vehicle, there are 8 holes in injector. If the
swirl is too strong, the injection angles might be overlapped and may cause the increased PM and
insufficient engine power. Also, if the injection pressure is too high during strong swirl, the injection
angles might be overlapped. Therefore, the system may decreases the fuel injection pressure when the
swirl is too strong.
Page 498 of 600
MAJOR CHANGES IN D27DTP (POWER UP) ENGINE
(COMPARED TO D27DT) 4.
The shape and size of D27DTP (POWER UP) are slightly different from those of D27DT engine
but the basic configuration of two systems is almost same.
1) Engine Assembly
Page 560 of 600
2) Traffic Conditions for Using Cruise Control
Use the cruise control system only when the traffic is not jammed, driving on motorways or
highways where there is no sudden change in the driving condition due to traffic lights, pedestrian,
etc.
Improper use of the cruise control could be dangerous.
- Do not use on winding roadsyy .
- Do not use in heavy traffic.
- Do not use on slippery, wet roads.
This could result in a loss of control, collision, and/or personal injuries.
Page 568 of 600

Do not move the shift lever to Neutral position while driving with the cruise control turned on.
Otherwise, it may result in system malfunction or accidents.
Always be prepared to use the brake or accelerator pedal for safe driving while the cruise
control system is running.
The actual speed can be different from the set speed momentarily when driving on a uphill
or downhill. So, it is recommended to disable the cruise control function on a uphill or
downhill. hen driving on a steep hill use the engine brake and foot brake properly to protect
the vehicle system and for a safe driving.
Ensure that the safe distance is maintained and use the brake pedal if needed. 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.
When the cruise control lever is faulty.
When the brake switch and the brake light switch input signal are implausible. 1.
2.
3.
When the cruise control function is cancelled abnormally or intermittent problems occur, stop the
vehicle and turn off the ignition switch and remove the key to reset the system. After a while, turn
on the ignition switch again to operate the cruise control system.
Page 581 of 600
0000-00
MAJOR CHANGES IN D27DTP (POWER UP) ENGINE
(COMPARED TO D27DT) 4.
The shape and size of D27DTP (POWER UP) are slightly different from those of D27DT engine
but the basic configuration of two systems is almost same.
1) Engine Assembly