EP2601497A1

EP2601497A1 - Apparatus for sensing a combustion chamber pressure in an internal combustion engine

Info

Publication number: EP2601497A1
Application number: EP11733844.2A
Authority: EP
Inventors: Holger Scholzen; Janpeter Wolff
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2010-08-02
Filing date: 2011-07-18
Publication date: 2013-06-12
Also published as: JP2013532832A; CN103026196A; DE102010038798A1; WO2012016811A1

Abstract

An apparatus for sensing a combustion chamber pressure in a combustion chamber (112) in an internal combustion engine is proposed. The apparatus comprises at least one housing (124), an adaptor element (142) held in the housing (124) and a mechanical/electrical transducer element (136) arranged in the housing (124), wherein the adaptor element (126) is operatively connected to a pressure sensor (116) and to at least one transmission element (156). The adaptor element (16) comprises a fixed element (144), connected to the housing (124), and a moving element (146), wherein the pressure sensor (116) engages on the moving element (146), and wherein the moving element (146) is set up to transmit at least some of a force exerted on the pressure sensor (116) by the combustion chamber pressure to the mechanical/electrical transducer element (136). The moving element (146) has a holder for the pressure sensor (116) on the combustion chamber side and a holder for the transmission element (156) on the interior side. The fixed element (144) and the moving element (146) have an elastically flexible web (147) of annular design formed between them.

Description

Description title

PRIOR ART For diesel engines, combustion chamber pressure sensors in which the combustion chamber pressure sensor is integrated in a glow plug are known from the prior art. For gasoline engines, the integration into engine components is also discussed in principle, for example, in a spark plug, but such integration in gasoline engines with significant disadvantages, especially in the

Sensor function, connected. From the post-published patent application DE 10

2009 026436.1 a device for detecting a combustion chamber pressure of an internal combustion engine is known which can be used in particular in gasoline engines or gasoline engines. In the device proposed there, a combustion chamber facing the opening of a sensor housing is closed by a membrane.

Within the sensor housing, a mechanical-electrical transducer element is accommodated, and there is provided a transmission element for transmitting a deformation of the membrane to the mechanical-electrical transducer element.

Despite the improvements of DE 10 2009 026436.1 there is still a need for easily manufactured, flexible integrated combustion chamber pressure sensors, in particular such combustion chamber pressure sensors, which may be used with minor modifications-both for diesel internal combustion engines and for Otto internal combustion engines. In particular, an increased would be

Built-in compatibility desirable, which would significantly reduce the cost of manufacture.

Disclosure of the invention

With the proposed device, a significantly increased installation compatibility is achieved. Furthermore, it is possible by the proposed device, apart from components that affect the glow function for a diesel variant, both for gasoline

Engines as well as diesel engines for identical or identical components too use. In this way, manufacturing costs and storage costs and the cost of providing different designs for auto-igniting internal combustion engines and non-self-igniting internal combustion engines can be significantly reduced.

The proposed device for detecting a combustion chamber pressure of a

Internal combustion engine has at least one housing, an adapter element accommodated in the housing and a mechanical-electrical housing arranged in the housing

Transducer element on. The adapter element is operatively connected to a pressure transducer and at least one transmission element and comprises a stationary element connected to the housing and a movable element, wherein the movable element of the pressure transducer engages, and wherein the movable member is adapted to a by the combustion chamber pressure on the Pressure Transducer applied force at least partially transmitted to the mechanical-electrical transducer element. Between the stationary element and the movable element, a ring-shaped flexurally elastic web is formed, which ensures the relative movement of the movable element as a flexible membrane.

A mechanical-electrical transducer element is generally to be understood as an element which can convert mechanical effects, for example a force and / or a pressure effect and / or a change in length of the transducer element, into electrical signals. In the following, reference is essentially made to piezoelectric transducer elements. Alternatively or additionally, however, the mechanical-electrical transducer element can also be other types of

Comprise transducer elements adapted to convert mechanical to electrical signals. Since, in the context of the present invention, a supply line to a pressure transducer, for example a glow plug or a glow plug, can be guided laterally past the mechanical-electrical transducer element, the mechanical-electrical transducer element can in particular be configured over the entire surface, for example as a full-surface disk without a central opening, for example as a circular disk or as a disk with a polygonal cross-section.

In the context of the present invention, a sensor housing is generally understood to mean an element which may be designed in one piece or also in several parts and which completely or partially surrounds the device or closes it to the outside. The sensor housing can in particular the outer shape of the device determine and can protect the device by a suitable mechanical stability, in particular from mechanical damage or mechanical and / or chemical and / or electrical influences. The sensor housing may further include one or more fasteners to fix the device, for example, in a wall of a combustion chamber of the internal combustion engine, for example, one or more threads.

Under a pressure transducer is generally to understand an element which is adapted to receive a force, pressure or deformation, which are caused by the pressure and / or pressure changes in the interior of the combustion chamber, and to the device, in particular directly or indirectly to the mechanical-electrical transducer element to forward. Embodiments of

Pressure transducer will be described in more detail below. The adapter element is configured to move one through the combustion chamber pressure to the

Pressure transducer applied force at least partially transmitted to the mechanical-electrical transducer element. In other words, the adapter element with the receptacle not only for mechanical recording and preferably (with the exception of movements caused by the combustion chamber pressure) fixation of

Serving pressure transducer, but also be itself part of a force path, through which pressures, movements, changes in length or forces, which are caused by the pressure in the combustion chamber, are transmitted from the pressure transducer to the mechanical-electrical transducer element. On the movable element is a combustion chamber side receptacle for the pressure transducer and an innraumseitige receptacle formed for the transmission element. The connections of the pressure receiving and the transmission element with the movable element can be made positive and / or non-positive. Alternatively or additionally, however, in principle, a cohesive connection is possible. It is particularly preferred if the movable element is designed as a sleeve with a first end face formed on a combustion chamber side opening and with a second end face formed on an inner side opening, wherein the pressure sensor can be fully or partially inserted into the combustion chamber side opening, so that the sleeve encloses the pressure transducer or a part of the pressure transducer. For example, the pressure transducer may have a projection, for example a cylindrical projection, in particular a circular cylindrical projection, which is completely or partially enclosed by the receptacle or a part of the receptacle. For example, at the transition between the

Projection and the remaining part of the pressure transducer shoulder be provided to a defined insertion of the pressure transducer in the

to cause the combustion chamber side opening. In principle, however, a different type of recording is possible. Alternatively, or in addition to an annular receptacle, the receptacle may also be one or more differently shaped

Have fasteners for securing the pressure transducer.

In particular, the pressure sensor may comprise a glow module, so that the device as a whole can be configured as a glow plug. Under a glow module is a module to understand how it is in self-igniting

Internal combustion engines can be used, for example in diesel engines, to effect or promote auto-ignition of the internal combustion engine,

for example, in one or more incandescent phases, for example Vorglühphasen. The glow module may in particular comprise one or more Glühstromleitungen, by means of which a heating of the Glühmoduls is effected. The glow module may in particular be connected to the receptacle in such a way that the glow module protrudes completely or partially out of the receptacle into the combustion chamber.

Alternatively, or in addition to a glow module, the device can as

Pressure sensor also include at least one sensor tip. Under one

Sensor tip is basically to understand a pressure transducer, which, preferably without other functions of electrical type exhibited, is adapted to receive pressures and / or forces from the combustion chamber for their forwarding. The sensor tip can in particular be designed as a purely mechanical component. In particular, the sensor tip at least one

Include combustion chamber facing plug and / or cover, which may be configured, for example, cylindrical. In particular, a blanking plug can be provided, which can be inserted or placed in the receptacle and / or on the receptacle. The plug may in particular, as well as the glow module, comprise a projection which can be inserted into an optionally annular designed receptacle. Various embodiments are possible and will be described in more detail below. The stationary element of the adapter element may be an annular part of the housing, for example a part of an inner housing which completely or partially encloses an interior space of the device and / or a sensor module of the device. Under the movable element is generally an element to understand which a change in position relative to the stationary element, ie in terms of the housing, for example, with respect to an outer housing, perform, in particular due to a change in pressure in the combustion chamber. While the stationary designed part is thus part of the rest of the housing, the movable element may be part of a force path, via which a movement, a force or a pressure from the combustion chamber to the mechanical-electrical

Transducer element is transmitted. The movable element in the form of the sleeve is suspended by means of a flexurally elastic web on the stationary element. The flexurally elastic web is designed, for example, like a membrane. In this or in other embodiments, the combustion chamber side recording of the movable element may be configured such that, for example, the

Inner housing, in which the mechanical-electrical transducer element

is received, not closed, but that the combustion chamber side opening remains. Such an open configuration facilitates, as will be explained in more detail below, in particular the implementation of one or more electrical leads of the pressure transducer, if necessary.

Between the innraumseitige recording and the mechanical-electrical

Transducer element may be arranged in particular at least one transmission element for transmitting force to the mechanical-electrical transducer element. Such a force transmission can basically the transfer of forces, pressures,

Movements or similar, caused by the combustion chamber pressure

include mechanical state changes. The transmission element may be designed in particular rod-shaped or annular. Particularly preferred is the embodiment as a one-piece or multi-part V-cylinder, the outside of which may be cylindrical or stepped. For example, that can

Transmission element on the side facing away from the combustion chamber on the receptacle, for example on the movable element of the receptacle, in particular the receiving ring to be supported. For this purpose, the transmission element, for example, in turn have a projection which projects into the interior side opening of the innraumseitigen recording. Again, alternatively or additionally, a groove or a shoulder may be provided on which the Receiving ring and / or designed differently receiving recording can be supported.

The transmission element may in particular have at least one passage for performing at least one electrical supply line of the pressure transducer.

In particular, this may be at least one bore,

preferably at least one eccentric bore. This bore may be arranged parallel to an axis of the device, but may in principle be arranged at an angle to the axis, for example at an angle between 5 degrees and 70 degrees, in particular a Wnkel between 30 degrees and 60 degrees. In this way it can be achieved that the supply line, which, for example, centrally from the pressure transducer, for example, the Glühmodul, on the

Combustion chamber remote from the side thereof can be guided laterally on the preferably arranged on the axis of the device mechanical-electrical transducer element and / or on parts of the transmission element. Wrd the implementation is not required and the recording is open to the combustion chamber, so through the pressure transducer, in particular through the sensor tip (preferably the plug), the implementation of the combustion chamber

be completed, so that no combustion gases directly through the

Implementation can reach the mechanical-electrical transducer element. The

Passage can extend through the entire transmission element or even merely through parts thereof, for example, only by an optional compensation body of the transmission element, which will be described in more detail below.

The transmission element can be designed in one piece or also in several parts.

It is particularly preferred if the transmission element comprises one or more compensation bodies for at least partial compensation of thermomechanical stresses. Thus, usually within the device,

especially within the sensor module of the device, different

Transmission paths for forces and / or linear expansion. Apart from the force path described above, via which forces, movements or pressures are transmitted directly from the pressure transducer to the mechanical-electrical transducer element, paths through the housing must also be considered. Since different materials can be accommodated in the transmission paths, which can have different thermal expansions, it can be at the high Temperature variations to which the device may be exposed result in thermo-mechanical stresses due to these different expansions. These thermo-mechanical stresses can lead to a falsification of measurement results or even damage to the device. The compensation element can be set up, for example, by a suitable choice of its length and / or its thermal expansion coefficient, so that the thermal expansions of the different transmission paths are at least largely identical, at least within typical temperature ranges to which the device can be exposed, for example within the scope of a tolerable deviation from not more than 20%, in particular not more than 10% and preferably not more than 5%. For example, you can

Temperature variations between -40 degrees Celsius and 150 degrees Celsius are present, with peak temperatures can also be higher. Within the stated temperature ranges, the one or more

Compensation elements for a compensation of the type described above provide. For example, this can be done by suitable choice of material, for. B. by using ceramic materials with appropriate properties.

The housing may in particular be designed in several parts and have at least one outer housing and at least one of the outer housing at least partially enclosed inner housing. The adapter element can

Accordingly, at least partially be part of the inner housing. This inner housing may in particular comprise an inner housing wall, wherein the adapter element is arranged on the combustion chamber side in the inner housing wall. This includes the case that the adapter element itself is part of the whole or in part, for example, with its part fixed to the housing

Interior housing wall is. For example, combustion chamber side, the inner housing by the adapter element, in particular its stationary part, and preferably also the pressure transducer be completed because, as stated above, preferably the adapter element is open towards the combustion chamber and can be completed by the pressure transducer. The inner housing wall can be closed on at least one fixation on a side facing away from the combustion chamber. The mechanical-electrical transducer element can be supported on this fixation. This multi-part embodiment can in particular realize the concept of the above-described multiple transmission paths. So can the actual Force path of the pressure transducer via the adapter element and optionally the transmission element to the mechanical-electrical transducer element lead. A second transmission path, via which, however, preferably no or a significantly lower transmission of forces and / or linear expansion takes place, can lead via the pressure sensor and the inner housing as well as the fixation to the mechanical-electrical transducer element. The one described above

Compensating body can provide compensation for thermo-mechanical stresses between these transmission paths. The inner housing wall may in particular have a cylindrical shape, in particular in the form of a hollow cylinder. The movable element, for example the receiving ring, can in particular extend from the inner housing wall into the interior of the inner housing and form the receptacle or a part of the receptacle there. The receiving ring may have a T-shape, in particular in a sectional plane parallel to an axis of the device, wherein the base of the T connects the receiving ring with the inner housing wall and wherein the transverse line of the T forms the actual recording.

embodiments

Embodiments of the invention are illustrated in the figures and are explained in more detail in the following description.

Show it:

Figure 1 shows a first embodiment of a device according to the invention for detecting a combustion chamber pressure in a combustion chamber of an internal combustion engine for use in self-igniting

Internal combustion engines, in particular diesel engines; and FIG. 2 shows an alternative embodiment of the device for FIG

Use in non-self-igniting internal combustion engines, especially in gasoline engines.

In Figures 1 and 2, various embodiments of the

Devices 110 according to the invention for detecting a combustion chamber pressure in a combustion chamber of an internal combustion engine shown. The combustion chamber is denoted symbolically in FIGS. 1 and 2 by the reference numeral 1 12 and is located in FIGS. 1 and 2 on the left of the device 1 10. FIG. 1 shows this

Embodiment of the device 1 10 for use in self-igniting Internal combustion engines, in particular diesel engines, whereas Figure 2 a

Embodiment of the device 1 10 for use in non-self-igniting internal combustion engines shows. In the following, reference will be made to these embodiments substantially simultaneously, which is an advantage of the present invention, many components of the apparatus 110 in both

Embodiments and can be used equally in both applications.

The device 110 essentially comprises two assemblies, namely one

While in the embodiment shown in Figure 1 for self-igniting internal combustion engines, the pressure transducer 1 16 16 includes a glow module 1 18, the pressure transducer comprises 1 16 in the embodiment for non-self-igniting internal combustion engine sensor tip 120th in the form of a plug 122. The plug 122 may be designed in particular in the form of a dummy plug and / or lid. The sensor unit 1 14 comprises a housing 124, which in this exemplary embodiment has an exemplary multi-part design. The housing 124 accordingly includes an outer housing 126 as well as one of these

enclosed inner housing 128. The inner housing 128 encloses with a substantially cylindrical in this embodiment configured

Inner housing wall 130 an interior 132 of the housing 124, in which a sensor module 134 with a mechanical-electrical transducer element 136, such as a piezoelectric element, is added. This is on one

Fixing element 140 supported on the side facing away from the combustion chamber 1 12 side of the housing 124 and is electrically contacted by sensor contacts 138, which are passed for example by the fixing element 140.

Within the outer housing 126, an adapter element 142 is arranged. In the exemplary embodiment illustrated, the adapter element 142 comprises a stationary element 144 which is arranged relative to the housing 124 and which forms part of the housing

Inner housing wall 130 may be, and a spaced from the stationary member 144 movable member 146. Between the stationary member 144 and the

movable member 146 is a flexurally elastic web 147 is formed. The stationary member 144 is annular and fixed to the inner wall of the outer housing 126 or is itself part of the outer housing 126. The movable member 146 is in the form of a sleeve 148 or a ring. The sleeve 148 or the ring indicates a combustion chamber side opening on a first end face and on the opposite inner side opening on a second end face. The first end surface forms a combustion chamber-side support surface 152 for the pressure sensor 116 and the second end surface forms an interior-side support surface 155 for a first transmission element 156. Through the openings of the interior 132 toward the

Combustion chamber open, but is closed by the pressure transducer 1 16. However, another embodiment is possible in principle.

The pressure transducer 1 16 has in the illustrated embodiment

Connecting element in the form of a projection 150 with an interior side shoulder 153 facing the interior 132, which is supported on the combustion chamber side support surface 152 of the movable member 146. Alternatively or additionally, a fixation of the pressure transducer 1 16 in the combustion chamber side opening take place, for example, a frictional, a positive or a cohesive fixation. A combination of different fixation types is possible.

The flexurally elastic web 147 is preferably as a ring-shaped or

disc-shaped closed web and forms a flexurally elastic membrane, which ensures the relative movement of the movable member 146 with respect to the stationary member 144. The closed web 147 forms a gas-tight partition between the combustion chamber 112 and the interior 132.

From the pressure transducer 116 combustion chamber pressures and / or forces are transmitted to the adapter element 142 and there in particular to the combustion chamber-side end face of the movable member 146. With the movable member 146 in FIG

Active compound is still facing the interior 132 facing first

Transmission element 156. The first transmission element 156 is on its side facing the pressure transducer 1 16 side also designed with a projection 158, which another, the combustion chamber 1 12 facing the combustion chamber side

Shoulder 160 trains. The combustion-chamber-side shoulder 160 of the transmission element 156 engages against the interior-side support surface 155 of the movable element 146. As a result, the force received by the pressure sensor 116 is transmitted via the movable element 146 to the first transmission element 156 and from there to another transmission element 154 of the sensor module 132 and again from there transmit the sensor module 132 and the mechanical-electrical transducer element 136 integrated therein.

The first transmission element 156 can serve, for example, as compensation body for compensation of thermo-mechanical stresses.

At the stationary element 144 of the adapter element 142, the inner housing 128 is secured to the inner housing wall 130. The inner housing 128 is further connected to a fixing element 140. The sensor module 132 is below the inner housing 128 between the movable member 146 and the fixing member 140 under

Preload arranged.

For the transmission of forces and / or combustion chamber pressures on the mechanical-electrical transducer element 136 thus serves a force path, which extends from the pressure transducer 1 16 via the movable member 146 and the first

Transmission element 156 and further transmission element 154 extends to the mechanical-electrical transducer element 136 of the sensor module 134. A second force path extends over the pressure transducer 1 16, the fixed element 144, and the fixing element 140. To compensate for different expansions of these transmission paths, the first executed as a compensation body

Transmission element 156.

While in the Otto engine variant according to Figure 2, the opening of the sleeve 148 combustion chamber side is closed only by the sensor tip 120 in the form of the plug 122, the pressure transducer comprises 16 16 in the diesel engine variant according to Figure 1, the glow module 118. This is basically einbaukompatibel respect to the pressure transducer 1 16 and the sensor tip 120 at the

The glow module 118 includes the actual glow plug 162, which is enclosed on the housing side by a support tube 164 which is fixedly connected to the glow plug 162, for example non-positively, positively or materially. The support tube 164 has the projection 150, which is inserted into the combustion chamber-side opening of the sleeve 148 and there with a unspecified shoulder as

inner side shoulder 153 on the combustion chamber side support surface 152 of the movable member 146 is supported. The glow module 118 is electrically contacted by means of one or more electrical leads 166, which also as Glühstromleitung be designated. The Glühstromleitung can be guided by one or more bushings 168, for example, one or more holes in the transmission element 154, for example, the compensation body 156, preferably eccentrically. This implementation can be done either axially, as shown, or obliquely. The eccentric passage causes the electrical supply line 166 also eccentrically through the interior 132 and thus exits laterally adjacent to the sensor module 134. The electrical supply line 166 preferably does not represent a disturbing contour next to the sensor module 134. In particular, because of this electrical supply line 166, it is not necessary to make the adjacent components smaller or to carry out any other redesign of the components accommodated in the interior 132.

On the side facing away from the combustion chamber 1 12 side of the sensor module 134, the electrical supply line 166 may be passed through a further passage 170, again an eccentric bore, through the fixing element 140,

for example, again axially (as shown in Figure 1) or obliquely to the axis. The feedthroughs 168, 170 for the electrical supply line 166 can also in the

Sensor unit 1 14 be present if they, as shown in Figure 2, are shown for non-self-igniting internal combustion engines such as gasoline engines. In this case, the bushings 168, 170, although without function, but can be used unchanged, since they are not hindering due to the sealing of the interior 132 by the pressure transducer 1 16.

On the side facing away from the combustion chamber 112 of the fixing element 140 is an electrical contacting of the sensor module 134 by means of the sensor contacts 138 and optionally (in the variant of Figure 1) of the electrical supply line 166 as in known from the prior art devices for combustion chamber pressure detection. Alternatively, it is also possible to lead the electrical supply line 166 laterally out of the rear region of the support tube 164 of the glow module 118, for example shortly before the compensation body. This variant is not shown.

Claims

claims

Anspruch [en] A device for detecting a combustion chamber pressure in a combustion chamber of an internal combustion engine having at least one housing (124), an adapter element (142) accommodated in the housing (124) and a mechanical-electrical transducer element (136) arranged in the housing (124)

Adapter element (126) with a pressure transducer (116) and with at least one transmission element (156) is in operative connection and comprises a housing (124) connected to the stationary element (144) and a movable element (146), wherein on the movable member (146 ) the pressure transducer (116) engages, and wherein the movable element (146) is arranged to at least partially transmit a force exerted by the combustion chamber pressure on the pressure transducer (116) to the mechanical-electrical transducer element (136), characterized in that between the stationary member (144) and the movable member (146) an annularly executed flexurally elastic web (147) is formed.

2. Device according to claim 1, wherein the flexurally elastic web (147) a

Partition wall to the interior (132) out forms.

3. A device according to claim 1, wherein the movable member (146) has a

combustion chamber-side receptacle for the pressure transducer (116) and a

Having interior space receiving the transmission element (156).

4. Device according to claim 1 or 3, wherein the movable element (146) in

Substantially in the form of a sleeve (148) having a combustion chamber side opening and an innraumseitigen opening.

5. Apparatus according to claim 4, wherein at the combustion chamber side opening a

On the combustion chamber side end face and on the interior side opening an inner side end face is formed, and wherein the combustion chamber side End face a first support surface (152) for the pressure transducer (116) and the inner side end face of a second support surface (155) for the

Forming transmission element (156).

6. Apparatus according to claim 5, wherein the pressure transducer (116) a

inner side shoulder (153), with which the pressure transducer (116) on the first support surface (152) is supported, and wherein the transmission element (156) has a combustion chamber pressure side shoulder (160) with which the

Transmission element (156) on the second support surface (155) is supported.

7. Device according to one of the two preceding claims, wherein the

Transmission element (156) is designed as a compensation body for at least partial compensation of thermo-mechanical stresses.

8. Device according to one of the preceding claims, wherein the housing (124) at least one outer housing (126) and at least one of the outer housing (126) at least partially enclosed inner housing (128), which is connected to a fixing element (140).

9. Apparatus according to claim 8, wherein the inner housing (128) with a

Inner housing wall (130) is fixedly connected to the stationary element (144) of the adapter element (142), wherein the mechanical-electrical transducer element (136) on the fixing element (140) is supported.

10. The apparatus of claim 9, wherein the sensor module (132) between the

movable element (146) and the fixing element (140) is biased.