Hyundai Yanmar TNV Series Manual page 49

CONTROL SYSTEM
Rack position sensor input
The Eco-governor controls the fuel injection quantity by adjusting the rack position of the fuel injection pump.
The rack position is converted into voltage by the rack position sensor, and the voltage signal is applied to E-
ECU terminal RPS and sent to an AD converter. The AD converter converts the input voltage of 0 to 5 volt
into an AD value of 0 to 1023. See Figure 2-14.
The Eco-governor controls the maximum and minimum rack positions and calculates the load factor on the
basis of this AD value.
5.0
0
Rack position [mm]
1023
0
Voltage [V]
Coolant temperature sensor input
The input characteristics of the coolant temperature sensor are shown in Figure 2-15. As in the case of the
rack position sensor, the input voltage of 0 to 5 volt is converted into an AD value of 0 to 1023. As is clear
from the figure, the thermistor resistance decreases with increasing temperatures.
The measurement error of the coolant temperature sensor is approximately ±3°C at 0°C and ±6°C at 110°C.
The coolant temperature sensor has been designed so that it provides high measurement accuracy at
relatively low temperatures to allow low-temperature control of CSD etc.
The E-ECU coverts the input voltage into temperatures by mapping. Connecting a thermistor with different
characteristics to the sensor or connecting an unintended load to the thermistor circuit will affect the
relationship between input voltage and temperature, resulting in failure to perform correct temperature
measurement. Do not connect a coolant temperature sensor other than the Yanmar genuine sensor to
terminal TW (E25 - E28) of the E-ECU.
30
25
20
15
10
5
0
-30 0
Figure 2-15 Characteristics of the coolant temperature sensor
2-30
Rack position sensor
(Magnetic type)
Voltage
5.0
Figure 2-14 Detection of rack position
Thermistor resistance [kΩ]
Input voltage [V]
30 60 90 120
Temperature [°C]
Rack position
Rack position Rack position
Map: AD values used
ECU
6
5
4
3
Input voltage [V]
2
1
0
TNV Application Manual
5.0V
1.5k
Thermistor