Shown on engine 926.9 |
A6 | Engine management (MR) control unit |
B10 | Fuel temperature sensor |
A | Input signals |
G07.15-A008-81
General
The properties of the fuel (volume, viscosity) change significantly as the temperature rises and falls so it is essential to determine the fuel temperature, particularly for calculating the start of injection or start of delivery.
The fuel temperature is also an important factor for calculating the delivery quantity since the actual mass of the fuel can be obtained from this, which is turn is essential for specified engine torque correction.
Function
The fuel temperature is determined by the engine management (MR) control unit from the measurement values supplied by the fuel temperature sensor.
There is a temperature-dependent resistor with a negative temperature coefficient (NTC) in the fuel temperature sensor, i.e. an electrical resistance that reduces as the temperature increases. The voltage applied to the engine management (MR) control unit changes according to the temperature of the fuel; the level of this voltage is what determines the fuel temperature.
If the fuel temperature sensor fails, the engine management (MR) control unit continues to operate with substitute values. This does, however, mean that optimum fuel consumption, pollutant emission levels etc. will no longer be achievable.