Kubota KX91-3a User Manual

II-152
WSM Minor Change II Service Engineering Section
(4)Idle-up control
The idling speed increases by 150 rpm when the water temperature drops below 30 centi-degrees.
(Reason:Even at the same governor position, the engine speed drops about 150 rpm at the temperature
of - 18 centi-degrees.)
<Function chart>
<Function diagram>
CPU in the controller unit detects the water temp sensor signal.
Stored program calculates the optimum idle speed according to the water temp. sensor value.
If the temp. value is over 30
°C (86°F), then CPU commands to output the preset idle PRM.
If the temp. value is below 30
°C (86°F), then CPU commands to output 150 rpm higher then the preset
idle speed.
Actual output from the controller is PWM current to the AI motor. Then AI motor rotates to regulate the
engine governor value which is always feed back to the controller.
Idle RPM
Set value
Idle RPM
-18 °C
Idle RPM + 150 RPM
30 °C
(86 °F)
Water temp. [°C]
-18 °C 30 °C
Actual
engine speed
1050
1200
Input signal
Water temp.
sensor
-18 °C
(Program control)
30 °C
(Y=X+150)
Water temp. [°C]
Governor
sensor
CPU
5 V
Y
X
Controller unit
Output
AI motor
Cable
Engine

Kubota KX91-3a Specifications

General

Brand	Kubota
Model	KX91-3a
Category	Excavators
Language	English