Robert Bosch measurements for 9 fuel properties

Fuel properties: measurements The HYD Bosch fuel properties are based on measurements in the temperature range +10 to +120 °C and the pressure range 0 to 2000 bar. These measurements allowed to define the coefficients used with the Bode’s state equation which is known to be predictive for high pressure with temperature dependency.

Siemens did not access the original measurements but only the Bosch GmbH’s FORTRAN code with the determined coefficients for the fuels. The Bosch GmbH’s test-bench used for measurements is not known by Siemens.

The temperature and pressure measured points and their P & T interval in between two measurements are similar to the following ones:

Figure 8: example of thermal conductivity measurements λ for RME (20%)+ Diesel (80%)

Then temperatures are [+10°C, +40°C, +80°C, +120°C] and pressures ranges are approximately every 200 bar = [0 bar, 200 bar, 400 bar, 600 bar, 800 bar, 1000 bar, 1200 bar, 1400 bar, 1600 bar, 1800 bar, 2000 bar].

Similar measurements were used to determine all the Bode’s coefficients for the 9 fuels.

Since it is a polynomial expression, the Bode’s state equation can be used between the initial measured points used to determine the coefficients, and outside the extreme measured points. Then, outside these P & T ranges, the fuel properties are obtained by extrapolation.

The properties values are finally saturated to constant values for temperatures outside [+243.15 K, +633.15 K] = [- 30°C, +360 °C] & for pressures outside [0, 5000 bar].