ENGINE | 642.896/992, 651 in MODEL 906 |
Shown on engine 642, view of the engine from the front |
B50 | Fuel temperature sensor (engine 642.9) |
B50/6 | Fuel temperature sensor (engine 642.8) |
D47.50-0005-06
Shown on engine 651 |
B50/5 | Fuel temperature sensor (engine 651) |
D07.02-1114-04
Location
The fuel temperature sensor (engine 642.8) or fuel temperature sensor (engine 642.9) is located on the high-pressure pump flange, the fuel temperature sensor (engine 651) in the return line of the high-pressure pump.
Task
The fuel temperature sensor (engine 642.8) or fuel temperature sensor (engine 642.9) detects the temperature of the fuel flowing in the high-pressure pump, the fuel temperature sensor (engine 651) detects the temperature of the fuel flowing out of the high-pressure pump.
Body
The fuel temperature sensor (engine 642.8/651) or the fuel temperature sensor (engine 642.9) is fitted with an integral precision resistor with a negative temperature coefficient (NTC).
Function
The NTC precision resistor alters its electrical resistance in line with the fuel temperature. The electrical resistance decreases as the fuel temperature rises. The change in the resistance creates a voltage signal that is used by the CDI control unit (N3/28) (engine 651) or CDI control unit (N3/30) (engine 642.8) or CDI control unit (N3/20) (engine 642.9) to compute the fuel temperature.