Measuring and testing – Fluid pressure gauge – With protective separator
Patent
1992-03-03
1994-05-31
Woodiel, Donald O.
Measuring and testing
Fluid pressure gauge
With protective separator
73115, 73721, 73727, 338 4, G01L 708, G01L 906
Patent
active
053158750
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a pressure sensor.
More particularly, the present invention relates to a pressure sensor in which a sensor element is composed of a piezoresistive material and arranged in a housing. In the case of such a pressure sensor, known from German Offenlegungsschrift 31 25 640.6, the piezoresistive measuring elements, such as for example thick-film resistors of cement, contactive plastic or platinum, are printed on a base. The resistor element and the base are arranged as close as possible to the pressure chamber in order to be able to determine the pressure prevailing there. Furthermore, the measuring signal is passed with the aid of electric leads to an electronic evaluation circuit arranged outside the housing of the pressure sensor. As a result, the piezoresistive elements and the electronic components have to be elaborately connected to one another with the aid of insulated pieces of wire. Since the piezoresistive measuring element is exposed directly to the pressure, it is also exposed to the high temperatures prevailing in the combustion chamber. The flames spread there at a temperature of about 2000.degree. C., whereby stresses can occur in the housing As a result, the pressure signal is falsified by the high temperatures.
Furthermore, European Preliminary Published Specification 85 111 895.0 discloses a pressure sensor in which the thick-film resistor is arranged on the bottom of a base. However, this pressure sensor is intended only for determining the pressure in distributor pumps. The high temperatures prevailing in the combustion chamber would falsify the measuring signal in the case of this design as well.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a pressure sensor for detecting pressure in a combustion chamber of internal combustion engines which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a pressure sensor in which between a diaphragm and a sensor element there is arranged a punch which introduces a pressure to be determined onto the sensor element, and the sensor element and a hybrid with its base and the electronic components of the preprocessing circuit arranged thereupon are located on a counterbearing of the punch. invention, it has the advantage that the piezoresistive measuring element is relatively far away from the combustion chamber and the high temperatures prevailing there, so that the measuring signal is not falsified by the temperatures prevailing in the combustion chamber. Due to the arrangement of the piezoresistive measuring element and the hybrid on the counterbearing of the punch, standard bonding techniques tried in practice can be used for connecting the electronic components and the piezoelectric elements. The various materials adapted to the respective printing techniques can be used as material for the base of the hybrid, which can also be used at the same time in an advantageous way as base for the thick-film resistors and semiconductor components. The hybrid can be printed in one operation simultaneously with the conductor tracks and the contact surfaces for the piezoresistive effect The entire hybrid, including the electronic components for signal preprocessing and the piezoresistive elements, can be checked before fitting into the sensor housing As a result, simple assembly of the pressure sensor is possible If the piezoresistive measuring element and the electronic components are on a common base, and if these components are arranged on the side of the counterbearing facing the diaphragm, its overall length can be reduced The hybrid can also be fitted into the housing of the pressure sensor in the axial direction of the latter without elaborate design modifications. If, for example, a flexible Kapton film is used, the piezoresistive measuring elements and electronic components can likewise be printed on in a single operation. Furthermore, t
REFERENCES:
patent: 3204463 (1965-09-01), Taber
patent: 4567395 (1986-01-01), Pundarika
patent: 4620438 (1986-04-01), Gazzano
patent: 5095741 (1992-03-01), Bartig et al.
Benedikt Walter
Herden Werner
Konrad Johann
Kuessel Matthias
Schmidt Wolfgang
Robert & Bosch GmbH
Striker Michael J.
Woodiel Donald O.
LandOfFree
Pressure sensor for detecting the pressure in the combustion cha does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pressure sensor for detecting the pressure in the combustion cha, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pressure sensor for detecting the pressure in the combustion cha will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1620644