Measuring and testing – Simulating operating condition – Marine
Reexamination Certificate
1999-10-22
2001-08-14
McCall, Eric S. (Department: 2855)
Measuring and testing
Simulating operating condition
Marine
Reexamination Certificate
active
06272913
ABSTRACT:
PRIOR ART
The invention relates first to an apparatus for detecting the pressure and temperature in the intake tube of an internal combustion engine, where a temperature sensor and a pressure sensor, the latter secured to a carrier together with an evaluation circuit with as little strain as possible, are disposed in a common housing.
An apparatus for detecting the pressure and the temperature in the intake tube of an internal combustion engine in which a temperature sensor and a pressure sensor are disposed in a common housing, is known for instance from German Patent DE 28 51 716 C1.
The combination of a pressure sensor known for instance from German Patent Disclosure DE 43 17 312 A1 with a temperature sensor is shown in FIG.
4
.
In the pressure sensor shown in
FIG. 4
, a single-chip silicon pressure sensor (not shown) is used, which includes a sensor cell in which the pressure is introduced to the back side of a diaphragm, and a reference vacuum is provided on the front side of the diaphragm for measuring the absolute pressure. The pressure sensor is accommodated in a hermetically sealed to housing
82
, which in turn is disposed in the housing
80
of the overall apparatus for detecting the pressure and the temperature. Also disposed in the housing
80
is a conductor plate
83
with capacitors, which are required with a view to electromagnetic compatibility. The conductor plate
83
also serves the purpose of a connection with flat plug contacts
84
, which are disposed in a stub
85
formed onto the housing
80
.
In a pressure stub
88
, there is also a temperature sensor
86
injection-molded into a tubular plastic sleeve
87
, the temperature sensor being in the form of an NTC resistor, whose terminal lines are electrically conductively connected to flat plug contacts
84
via inlay parts
90
welded to the NTC wires.
This kind of apparatus for detecting the pressure and temperature is not only very complicated to produce; for instance, the electrical connections between the terminal lines of the temperature sensor
86
and of the pressure sensor
82
and the conductor plate
85
and the flat plug contacts
84
must be made in the fully assembled state by means of a soldered connection. This soldered connection must then be potted for sealing purposes with an adhesive composition
89
, for instance.
It is also problematic in such an apparatus that the temperature sensor
86
is disposed in a plastic sleeve
87
, because this results in what for many applications is an excessively long response time of the temperature sensor
86
.
German Patent Application 197 11 939.5, which was not published prior to the priority date of the present application, discloses an apparatus for detecting the pressure and the temperature in the intake tube of an internal combustion engine in which, to introduce a medium that is under pressure, a stub part secured to the housing and an adapter piece connected both to the carrier and to the stub part via sealing adhesives that decouple mechanical strains are provided.
Such an apparatus does enable very good decoupling of strain by means of the adapter, which is connected both to the stub part and to the carrier solely via elastic sealing adhesives. However, its relatively complicated manufacture is problematic in such an apparatus. That is, first the adapter has to be secured to the carrier before the stub part can finally be secured.
Furthermore, strain in the pressure sensor cannot be precluded completely, because the carrier is secured to a housing wall and to that extent is acted upon on one side by pressure that acts on the pressure sensor, so that slight strains can still occur.
It is therefore an object of the invention to refine an apparatus for detecting the pressure and temperature in the intake tube of an internal combustion engine as generically defined above in such a way that while being very simple to produce it enables very precise pressure measurement.
ADVANTAGES OF THE INVENTION
This object is attained, in an apparatus for detecting the pressure and temperature in the intake tube of an internal combustion engine of the type described at the outset, according to the invention in that the housing includes at least two chambers separate from one another. One chamber forms a pressure chamber communicating with the intake tube via a stub and sealed off from the environment. The pressure chamber protrudes into the part of the carrier on which the pressure sensor is secured, and the other chamber serves to receive and secure the remaining portion of the carrier with electrical connection elements, and for securing the carrier and sealing off the pressure chamber, sealing adhesive connections that decouple mechanical strains are provided.
Dividing the housing into at least two chambers separate from one another, into one of which the part of the carrier to which the pressure sensor with the evaluation circuit is secured protrudes and the other serves to secure the remainder of the carrier with the electrical connection elements, where sealing adhesive connections that decouple mechanical strains are provided for securing the carrier and sealing off the pressure chamber, has the particularly great advantage that the part to which the pressure sensor is secured is acted upon by pressure on all sides in the pressure chamber. As a result, mechanical strains on the carrier are better avoided than when the sensor is secured to a housing wall, for instance. It is also especially advantageous that intermediate parts of any kind can be dispensed with between the stub and the carrier, because the pressure chamber communicates with the intake tube directly via the stub.
Particularly with a view to simple assembly, to be described in further detail hereinafter, it has proved to be especially advantageous that the housing includes a base part, on which the stub is disposed and the carrier plate is secured by sealing adhesive connections that decouple mechanical strains, and a cap part connected to the base part that is disposed lying above the carrier and has a wall for forming the two chambers, in which the wall is connected to the carrier by a sealing adhesive connection that decouples mechanical strains.
To avoid strains on the cap part secured to the base part that can be transmitted to the carrier and thus to the pressure sensor, it is advantageously provided that the cap part is secured to the base part solely via sealing adhesive connections that decouple mechanical strains.
Purely in principle, the carrier part to which the pressure sensor is secured can protrude, floating freely, into the pressure chamber. An embodiment that is especially advantageous for the sake of assembly provides that a bearing face is provided on the base part in the pressure chamber, and the carrier is secured to this bearing face by a sealing adhesive that decouple mechanical strains.
To protect the pressure sensor from environmental influences, it is advantageously provided that a ring is disposed around the pressure sensor, and that the interstice between the ring and the pressure sensor is filled with a chemical-resistant gel.
For this purpose, fluorosilicone gel has proved especially advantageous.
To enable an especially direct coupling of the temperature sensor to the medium to be measured, it is advantageously provided that the temperature sensor is secured to the base part in such a way that it protrudes into the interior of the stub.
Purely in principle, the temperature sensor can be secured in the stub in various ways.
In one embodiment, it is provided that the terminal lines of the temperature sensor are clamped to two cheeks formed on the stub by a resilient clip bracket formed onto the stub. In this way, the temperature sensor can not only be mounted and positioned on the stub in a very simple way, but furthermore, because of the clamping connection imparted by the clip bracket, it becomes possible to secure the terminal lines of the temperature sensor without damage.
To assure that the temperature sensor and its terminal lines will not corrode or
Kuhnt Winfried
Naegele Erwin
Greigg Edwin E.
Greigg Ronald E.
McCall Eric S.
Robert & Bosch GmbH
LandOfFree
Apparatus for detecting the pressure and temperature in the... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for detecting the pressure and temperature in the..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for detecting the pressure and temperature in the... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2477799