GF07.15-W-4008B | Determination of the fuel temperature, function | 3.8.04 |
ENGINE 457.9 in MODEL 375 with BODY 375.840
ENGINE 457.9 in MODEL 944 with BODY 944.899
W07.15-1321-81
A6 MR/PLD control unit
B10 Fuel temperature sensor
General
The properties of the fuel (volume, viscosity) change significantly with increases or decreases in temperature 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 fuel quantity as one can obtain the actual mass of the fuel from this which in turn is essential for specified engine torque correction.
Function
The fuel temperature is determined by the MR/PLD control unit (A6) from the readings supplied by the fuel temperature sensor (B10).
A temperature-dependent resistance with a negative temperature coefficient (NTC) - i.e. an electrical resistance which reduces as the temperature increases, is located in the fuel temperature sensor (B10). The voltage being applied to the MR/PLD control unit (A6) alters according to the temperature of the fuel, the value of which is the basis for calculating the fuel temperature.
The engine control (MR) control unit will operate using substitute values if the fuel temperature sensor (B10) fails. This does, however, mean that optimum fuel consumption, pollutant emission levels etc. will no longer be achievable.