Bosch GmbH, initial work with Dr Egler

Dr Egler HYD Bosch fuel properties are computed in the Simcenter Amesim utility called boschprops.c. This utility is the transfer of a Bosch GmbH FORTRAN code for fuel property computation into the Simcenter Amesim Hydraulic library. This work was based on Dr Egler’s method used in former initial FORTRAN code and supplied to Siemens.

The fuel properties models developed by BOSCH GmbH were used in an in-house simulation software to produce results for diesel injection systems. These injection system simulations were validated with experimental measurements. Note that it was at a very early stage of 1D simulation software developments at a time when commercial 1D software didn’t exist for injection systems simulation.

Below are reproduced some slides to highlight the quality of the simulation results at that time:

Figure 1: Extracts from very early 1D modeling on diesel injection system

In 1994, Dr Egler wrote “Der Einfluss der Thermodynamik auf die Hochdruckhydraulik und ihre Integration in moderne Entwicklungswerkzeuge für Dieseleinspritzausrüstungen bei des Robert Bosch GmbH”, which means :

“The influence of thermodynamics on high pressure hydraulics and its integration into modern development tools for Diesel injection equipment with Robert Bosch GmbH”.

Bosch Fuel properties pushed in the Simcenter Amesim Hydraulic library are based on the assumptions described in this document.

The Dr Egler’s references for developing these fuel properties models with their associated assumptions were:

[1] Fuchs, W.: Berechnung des Einspritzverlaufs beim Pumpe-Düse-System. Technische Universität Graz. Dissertation Juni 1984.

In English: Computation of the injecting process with the pump nozzle system

[2] Wannenwetsch, P. u. Egler, W.: A User-Friendly Program System for Digital Simulation of Hydraulic Equipment. SAE-Paper 850 532 (1985).

[3] Bode, B.: Verfahren zur Extrapolation wichtiger Stoffeigenschaften von Flüssigkeiten unter hohem Druck.Tribologie+Schmierung 37 (1990).

In English: Procedure for the extrapolation of important material properties of liquids under high pressure

[4] Truckenbrodt, E.: Fluidmechanik, Band l, 3. Auflage. Berlin, Heidelberg. New York: Springer 1989.

In English: Fluid mechanic

These articles can be normally ordered from scientific organisms to access the contents. For copyright reasons, they can’t be reproduced here.

Article [3] from Bode is the most relevant since it is really at the root of some of the main assumptions used in the HYD Bosch Fuel Properties models.

Additionally, the main input was the Bosch GmbH’s FORTRAN code for fuel properties computations.

Some tests have been done during the industrialization to certify the predictability of the fuel models with respect to the conservation laws (mass, energy, …). The strategy formulated by Siemens was to completely reproduce density measurements rather than speed of sound. Actually, initial Bosch GmbH’s FORTRAN code showed discrepancies in satisfying conservation laws when trying to reproduce both density measurements and speed of sound.

Some comparisons have been done between HYD Bosch Fuel Properties and Bosch GmbH’s FORTRAN code properties to ensure the quality of the fuel properties results.

Finally, some adaptations have been achieved to include cavitation/aeration, after a common work with Bosch GmbH to define the best cavitation/aeration model to be included in a 1D simulation software such as Simcenter Amesim.