This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
A Ti/Pt Hot Film Anemometer for CR-Injection Systems
Technical Paper
2002-01-2155
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
By e-beam evaporating a thin film resistor, consisting of a Titanium (≈10nm)/Platinum (≈100nm) bi-layer, on a LTCC (Low Temperature Cofired Ceramic) substrate, a robust and fast responding thermal mass flow sensor is developed. Due to the integration of the latter into the nozzle of a Common Rail (CR) injection system, important parameters, as the injection rate as well as the begin/end of the injection pulse, can be determined with high accuracy. By a closed-loop control of the magnetic or piezo-electric driven valve, a smooth combustion process with lower NOx emission values could be achieved. This present paper mainly focuses on analytical calculations to determine the velocity and temperature sensitivity of the thermal mass flow sensors in the constant-current (CC) mode. Because of the cross sensitivity of the thermo-resistive measurement principle, a second thin film resistor, fabricated with the same technology and operated in the low temperature regime, is desired, to detect any temperature changes of the fuel for a proper interpretation of the sensor signals. Further on, the first injection rate measurements up to 130 MPa are presented and the sensor characteristics, which yield high amplitudes during injection, are discussed. For a long-term reliable operation of the hot film anemometers under these harsh environmental conditions, a proper passivation technology is indispensable. Amorphous silicon carbide (a-SiC:H) exhibits an excellent coverage of the surface and a good adhesion to the glass ceramic substrate, enabling a clear reduction of drift effects on sensor constants in oil atmosphere. atmosphere. atmosphere.
Recommended Content
Authors
Topic
Citation
Schmid, U. and Krötz, G., "A Ti/Pt Hot Film Anemometer for CR-Injection Systems," SAE Technical Paper 2002-01-2155, 2002, https://doi.org/10.4271/2002-01-2155.Also In
SAE 2002 Transactions Journal of Passenger Cars - Electronic and Electrical Systems
Number: V111-7; Published: 2003-09-15
Number: V111-7; Published: 2003-09-15
References
- Schmid U. Krötz G. Schmitt-Landsiedel D. “On board injection rate measurements at DI-Systems with a micromachined mass flow sensor” Technical SAE Paper No: 2001-01-3277 ATTCE Barcelona October 2001
- Schmid U. Krötz G. “A thermo-resistive flow sensor for injection rate measurements” Technical SAE Paper No.:2002-02-0212, SAE World Congress Detroit March 2002
- Klumpp A. Schaber U. Offereins H.L. Kühl K. Sandmaier H. “Amorphous silicon carbide and its application in silicon micromachining” Sensors and Materials 6 6 349 358 1994
- Schmid U. Krötz G. Öing H. Renner G. Schmitt-Landsiedel D. “A flow sensor for harsh environmental automotive applications” 10 th Intern. Conf. Sensor2001 Nuremberg 1 25 30 May 2001
- King L. V. “On the convection of heat from small cylinders in a stream of fluid: Determination of the convection constants of small platinum wires, with application to hot wire anemometry” Proc. Roy. Soc. 90 563 570 1914
- Lomas C.G. “Fundamentals of hot wire anemometry” Cambridge University Press 0 521 30340 0 1986
- Bruun H.H. “Hot wire anemometry-principles and signal analysis” Oxford University Press 0 19 856342 6 1995
- Hinze J.O. “Turbulence-An introduction to its mechanism and theory” Mc Graw-Hill New York 1959
- Freymuth P. “Frequency response and electronic testing for constant-temperature hot wire anemometers” J. Phys. E.: Sci. Instr. 10 705 710 1977
- Chopra K. L. “Thin film phenomena” McGraw-Hill Book Company 1969
- Kuchling H. “Taschenbuch der Physik” Fachbuchverlag Leipzig 3-343-00759-5 1986
- Eckelmann H. “Hot wire and hot film measurements in oil” DISA Info 13 16 22 1972