GF18.40-P-2000MOR | Component description for oil sensor | 13.11.08 |
ENGINE 275.9 in MODEL 230.4 as of model Year 2009
/ AEJ 08 model refinement package
P18.40-2130-11
Illustrated on model 240
B40 Oil sensor (oil level, temperature and quality)
Arrow: Connector with electronics
Location
The oil sensor is located in the oil pan.
Its connector with electronics is located at the left or right side of the oil pan depending on the oil pan shape.
Task
The oil sensor detects:
- Oil level
- Oil temperature
- Oil quality (for demand-based oil change interval display)
P18.40-2104-11
Design
1 Electronics with 3-pin plug connection
B40 Oil sensor (oil level, temperature and quality)
a Capacitive measuring range
C Plug connectors:
Pin 1: output signal
Pin 2: ground
Pin 3: voltage supply
Function
The oil sensor operates in accordance with the capacitive measuring principle and features integrated electronics that evaluates three signals (oil level, temperature and quality).
Oil temperature
The oil temperature is detected by the temperature sensor.
Oil level and oil quality
Oil level and oil quality are detected on the basis of the capacitance of the engine oil (dielectric).
The capacitance of the engine oil is as much as 6 times greater if the oil quality is poor.
The measuring range for the oil level is 80 mm (normal level 40 mm) for a measuring accuracy of about ca. 3 mm.
Oil level and oil quality (capacitance of the engine oil) are interdependent. Therefore this information is compensated in the ME-SFI [ME] control unit (N3/10) only before it is transmitted further.
Oil sensor signal
All the signals are processed in the integrated electronics in the oil sensor to form a PWM signal and passed on to the ME-SFI [ME] control unit.
After this, the information from the ME-SFI [ME] control unit is passed on to the instrument cluster (A1) via the engine compartment CAN (CAN C).
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 (T) of approx. 20 to 80 %.
Power for the oil sensor (approx. 5 V) is supplied by the ME control unit.
Faults at the oil sensor are detected by the ME control unit and entered in the fault memory.
P07.61-0445-05
Oil sensor signal assignment
1 Signal duty cycle OK
A Oil temperature 20 to 80%
B Oil level 20 to 80%
C Oil quality 20 to 80%
2 Signal duty cycle >80%
A Oil temperature >+160°C
B Oil level >80 mm
C Oil quality good
3 Signal duty cycle <20%
A Oil temperature <- 40°C
B Oil level <0 mm
C Oil quality poor
T pulse duty factor 100%