GF18.40-P-2000TG | Component description of oil sensor | 21.12.04 |
ENGINE 629 in MODEL 164.1 /8, 221.0 /1 up to Model Year 8
ENGINE 629 in MODEL 211.0
P18.40-2213-06
B40 Oil sensor (oil level, temperature and quality)
Location
The oil sensor is fitted to the small oil pan on the transmission side, on the right side of the engine.
Task
To warn the driver by means of a display in the instrument cluster (A1) that the oil level is too low
Detecting the oil temperature.
Detecting oil quality for demand-based oil change interval display
P18.40-2045-12
Design
2 Temperature sensor
A Capacitive measuring range
B40 Oil sensor (oil level, temperature and quality)
Oil sensor signal assignment
1 Duty cycle signals OK
A Oil temperature 20 to 80 %
B Oil level 20 to 80 %
C Oil quality 20 to 80 %
2 Duty cycle signals > 80 %
A Oil temperature > +160 °C
B Oil level > 80 mm
C Oil quality good
3 Duty cycle signals < 20 %
A Oil temperature < - 40 °C
B Oil level < 0 mm
C Oil quality poor
T
T
T
1 s + 200 ms
1 s + 200 ms
5V
1
0V
(%)
0
60
0
50
0
30
2
(%)
0
81
0
81
0
81
3
(%)
0
19
0
19
0
15
A
B
C
Function
The oil level, oil temperature and oil quality are detected by means of an oil sensor installed in the oil pan. The sensor operates in accordance with the capacitive measuring principle and features integrated electronics which analyze the three signals. The information is continuously sent via a pulse width modulate (PWM) signal to the CDI control unit (N3/9) and via the Control Area Network (databus/CAN Bus) (CAN) to the instrument cluster. Each information block consists of three successive square-wave signals, This is followed by a short pause. A measured variable is assigned to each square-wave signal (A, B, C). The quantisizing in each case is based on the on/off ratio of approx. 20 to 80 %. The oil quality is measured for the demand-based oil change interval display.
The oil quality is detected on the basis of the capacitance of the engine oil (dielectrics), this being as much as 6 times greater in the case of poor oil quality. The measuring range for the oil level is
80 mm, the measuring accuracy approx. 3 mm. The oil level and the oil quality (engine oil capacity) are interdependent. The information is first of all calculated in the CDI control unit before being transmitted over the CAN. Faults at the oil sensor (oil level, temperature and quality) are detected by the CDI control unit and entered in the fault memory. The voltage supply (around 5 V) for the oil sensor (oil level, temperature and quality) is provided by the CDI control unit.