Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
  • G01L19/04—Means for compensating for effects of changes of temperature, i.e. other than electric compensation
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D11/00—Component parts of measuring arrangements not specially adapted for a specific variable
  • G01D11/24—Housings ; Casings for instruments
  • G01D11/245—Housings for sensors
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L23/00—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid
  • G01L23/22—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines
  • G01L23/221—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines for detecting or indicating knocks in internal combustion engines
  • G01L23/222—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines for detecting or indicating knocks in internal combustion engines using piezoelectric devices

Definitions

• the invention relates to a device for detecting a combustion chamber pressure of an internal combustion engine, which can be used in particular in gasoline engines or gasoline engines.
• Such devices form an integral part of modem engine controls, since the combustion chamber pressure must be detected very precisely, in particular for the purpose of reducing consumption and emissions.
• Combustion chamber pressure of an internal combustion engine which has a glow plug with a housing jacket extending in a direction of installation of the glow plug and a pressure sensing element accommodated in the glow plug.
• the housing jacket of the glow plug is used to transmit the combustion chamber pressure to the pressure sensing element.
• WO 2006/089446 A1 describes a component for installation in force or pressure sensors, in particular in a glow plug.
• the component comprises a disk-shaped or perforated disc-shaped measuring element made of piezoelectric material and on both sides of the measuring element fitting hole-disc-shaped or disc-shaped electrodes with contact points for contact with lines. Furthermore, one or more transmission bodies arranged on both sides outside the electrodes are provided.
• the device can be used in particular in gasoline engines.
• the device comprises at least one sensor housing, that is to say an element which completely or partially encloses further components, for example a sensor housing designed at least partially in the form of a hollow cylinder.
• the sensor housing may for example be made of a metallic material and is arranged to be at least partially introduced into the combustion chamber of the internal combustion engine. For example, that can
• Sensor housing are fixed directly or indirectly in a combustion chamber wall of the internal combustion engine, so that the sensor housing protrudes at least partially, for example, with its front end into the combustion chamber of the internal combustion engine.
• the sensor housing has on the combustion chamber side an opening closed by at least one membrane.
• it may be a circular or polygonal opening.
• a membrane may, for example, be understood to mean an element which is deformable or movable at least in one direction and extends, for example, perpendicular to an axis of the sensor housing whose lateral extent preferably has its thickness at least one factor
• the membrane can be designed, for example, as a metallic membrane, for example as a metal foil, and can also be integrally formed with the sensor housing and / or be frictionally and / or positively and / or materially connected to the sensor housing in the region of the opening. It is particularly preferred if the
• Sensor housing is formed at least in the region of the opening of a hollow cylinder, wherein the membrane, for example as a metallic membrane, for example, to the Sen- Sorgeophuse is welded to the surrounding the opening edge of the sensor housing.
• the membrane for example as a metallic membrane, for example, to the Sen- Sorgeophuse is welded to the surrounding the opening edge of the sensor housing.
• another type of connection to the sensor housing is in principle possible, for example, a frictional connection, for example by a union nut.
• the membrane should preferably close the opening completely pressure-tight, at least in the range usually occurring in combustion chambers pressures.
• the device further comprises at least one mechanical-electrical transducer element in the sensor housing.
• This is generally to be understood as meaning an element, which mechanical influences, for example a force and / or a force
• Pressure action and / or a change in length of the transducer element can convert into electrical signals.
• the mechanical-electrical transducer element can also comprise other types of transducer elements that are set up to convert mechanical signals into electrical signals.
• the device has at least one transmission element, which is formed separately from the sensor housing, for transmitting a deformation of the diaphragm to the mechanical-electrical transducer element.
• a combustion chamber pressure-related deflection of the membrane can be transmitted via the transmission element to the mechanical-electrical transducer element, so that an electrical signal corresponding to the deflection of the membrane and thus corresponding to the combustion chamber pressure can be generated.
• a transmission element is basically to understand any element by means of which, preferably substantially rigid, movements and / or deformations of the membrane can also be transmitted axially to the mechanical electrical transducer element.
• the transmission element can be designed substantially rod-shaped and can preferably be mounted on an axis of the device.
• the transmission element can also be designed in several parts.
• the transmission element is, as shown above, formed separately from the sensor housing.
• the device has at least two transmission paths, via which forces and / or changes in length of components of the device exposed directly to the combustion chamber, for example the membrane and / or an end face of the sensor housing facing the combustion chamber, can be transmitted to the mechanical-electrical transducer element ,
• the sensor housing itself may be part of a first transmission path, - A -
• the transmission element is part of a second transmission path that is not substantially coupled to the first transmission path.
• thermally induced expansions of the device can be transmitted to the mechanical-electrical converter element via the first transmission path and the second transmission path, preferably substantially without coupling of the two paths. This will be explained in more detail below.
• the first transmission path may concentrically surround the second transmission path.
• the device has at least one compensation body for compensating different thermal expansions in the two transmission paths.
• the transmission element itself comprises at least one compensation body which is set up to compensate for different Liehe thermal expansions between the first transmission path and the second transmission path.
• the compensation body can be set up with respect to its length and coefficient of thermal expansion such that it ensures that the thermal expansions of the first and second transmission paths are at least substantially identical, at least within typical temperature ranges to which the device may be exposed, for example in the US Pat Within a tolerable deviation of not more than 20%, in particular not more than 10% and preferably not more than 5%.
• the described transmission path will typically not heat through homogeneously, but it will usually be a temperature gradient from the combustion chamber, for example at a membrane temperature to about 550 0 C, up to the mechanical-electrical transducer element, for example, a temperature of the piezoelectric Quartz from about up to 200 0 C, set.
• the temperature compensation can then, for example, based on empirically determined, for example, determined by engine measurements, temperature gradients occur.
• a temperature compensation is typically only possible for either homogeneous temperatures or for temperature gradients, in particular homogeneous temperature gradients.
• the temperature compensation is designed so that a biasing force, such as a biasing force of the mechanical-electrical transducer element, does not change or changes only insignificantly in the transition from an idle temperature gradient to a full load temperature gradient or vice versa.
• a biasing force such as a biasing force of the mechanical-electrical transducer element
• An amendment tion of the biasing force by changing the ambient temperature can be tolerated in this case usually because typically has a high time constant and usually in particular in connection with a reset of a measurement signal, for example after each cycle, the influence of the measurement signal is negligible.
• the at least one compensation body the at least one compensation body
• Transmission element which may also be constructed in several parts, also have at least one thermal insulation body with thermally insulating properties.
• the thermal insulation insulator may comprise at least one ceramic material, which may have high thermal insulating properties. Other types of materials are possible.
• the thermal insulation insulator is also buildable in several parts.
• the thermal insulation insulator may furthermore also have electrically insulating properties. This can be ensured by virtue of the fact that the heat insulation insulator with the thermally insulating properties itself also has electrically insulating properties.
• a multi-part construction may also be provided, in which the thermal insulation body has at least one electrically insulating component in addition to at least one thermally insulating component.
• the device may further comprise at least one contact element for electrical contacting of the mechanical-electrical transducer element.
• it can be a rigid contact element, that is to say a contact element which does not change its shape under the effect of its own weight force or only insignificantly changes its shape.
• the contact element can have at least one current Include rail, so a rigid element which has current-conducting properties, such as a metallic element.
• the contact element should preferably be set up in such a way that it has at least partially, for example in sections, an axial flexibility, ie a flexibility in its longitudinal extension direction, for example parallel to the axis of the device. This can for example be achieved in that the contact element is at least partially designed with resilient properties.
• the contact element for example, the at least one busbar, for example, at least partially allow flexibility in the sensor longitudinal direction in that a double impact is provided.
• This can be done, for example, analogous to a corrugated board, for example by a bus bar is designed with two outer webs, between which at least one resilient element is provided, for example, a folded metallic sheet.
• an axial flexibility of the contact element can be provided, in particular in the region of a contacting of the mechanical-electrical Wandlerele- element, for example by the contact element is designed, for example, bent, that this one or more sections having an extension perpendicular to the axis.
• the one or more contact elements can contribute to a strain relief of the mechanical-electrical transducer element, so that although, for example, a force on the mechanical-electrical transducer element is possible, however, an example impressed by stresses path to the mechanical-electrical Transducer element is reduced. However, this path is important for an error signal generated by the tensions in the mechanical-electrical transducer element, such as a piezo-quartz.
• the mechanical-electrical transducer element may be mounted directly or indirectly against an insulating body on its side facing away from the combustion chamber side.
• This insulating body can, for example, have electrically insulating properties.
• the mechanical-electrical converter element alternatively or additionally, may be mounted directly or indirectly against the sensor housing on its side facing away from the combustion chamber via at least one fixing.
• the fixation can be, for example, a metallic fixation, for example a metal ring, which can be connected to the sensor housing, for example, in a material-locking and / or positive-locking and / or force-locking manner. Particularly preferred is a welding of the
• the mechanical-electrical transducer element may be further separated from the sensor housing by at least one sensor holder.
• this sensor holder can comprise a sensor holder which at least partially surrounds the mechanical-electrical converter element, in particular enclosing it, for example a sensor holder surrounding this converter element concentrically.
• This sensor holder may for example be configured at least partially as a sleeve.
• the sensor holder may have, for example, thermally and / or electrically insulating properties and / or vibration-damping properties.
• the sensor holder may for example wholly or partly made of plastic, ceramic, polyceramic or
• the sensor holder may also at least partially enclose at least part of the transmission element, for example the thermal insulation body and / or the compensation body. In this way, the two transmission paths described above can be additionally separated from each other.
• the sensor holder itself should not have direct contact with the membrane, so that the sensor holder itself preferably does not form part of the above-mentioned transmission paths.
• the sensor holder may comprise and / or enclose further elements of the device, in particular further elements which form part of the second transmission path.
• the sensor holder can at least partly surround elements, for example the insulating body, on the side of the mechanical-electrical converter element facing away from the combustion chamber.
• the device may further comprise at least one sealing housing enclosing at least partially the sensor housing, for example a sealing cone housing.
• This sealing housing can be set up to allow a fixation of the device in a combustion chamber wall, so that at least the membrane can be acted upon by a chamber-side pressure.
• this fixation may include a non-positive and / or positive fixing, for example screwing into a room wall.
• a sealing cone on the sealing housing for example, increase the sealing effect, for example, to induce no leaks in a cylinder head.
• the sealing housing should be configured in this way, for example, be connected to the sensor housing such that the mechanical-electrical transducer element is mounted outside of the combustion chamber.
• the mechanical-electrical conversion element may be arranged in a region in which temperatures of not more than 200 ° C occur.
• the sealing housing may for example be connected to the sensor housing in such a way that the sensor housing remains substantially tension-free and / or torsion-free during fixing of the sealing housing in the combustion chamber wall, for example when screwed into a cylinder head, so that no axial stresses and / or torsional stresses be transferred to the mechanical-electrical transducer element.
• This can be ensured, for example, by virtue of the fact that the sealing housing at least partially surrounds the sensor housing, but is connected to it, for example, only in one area or in several uncritical areas, for example by a cohesive and / or positive connection, for example in the form of a welded seam, preferably a single one
• Weld for example, a single circumferential weld.
• Axial stresses and / or torsional stresses in the sealing housing which may occur during fixing in the combustion chamber wall, are then not transferred to the interior of the sensor housing, and thus not to the mechanical-electrical transducer element.
• transmission of radial stresses can be tolerated to some extent.
• the sensor housing and the first and / or the second transmission path can thus be configured mechanically decoupled from the sealing housing, for example by the one weld.
• an axial compression and / or a torsional stress which can be generated in particular by a screwing in within the sealing housing, do not act on the first and / or second transmission path, so that they not or only insignificantly on the pressure measurement or force measurement can affect.
• the proposed device in one or more of the embodiments described above has numerous advantages over known devices, which have a positive effect in particular when used in gasoline engines.
• the device is designed such that high temperatures occurring during combustion in the combustion chamber can not or only insignificantly influence the signals.
• the pressure signal from the combustion chamber can be forwarded within the device into a region in which compatible temperatures for the mechanical-electrical transducer element are present.
• the proposed structure also enables measurement signal transmission with minimal signal reduction and / or signal transmission. change.
• external mechanical influences such as the screwing-in torque, are kept away from the second transmission path, ie from the transmission path of the pressure, the force and the electrical signal.
• the pressure signal can be converted into a force with low losses, forwarded to the measuring element and converted there into an electrical signal, which in turn are led to an evaluation circuit which is integrated in the device itself and / or which is arranged completely or partially outside the device.
• the mechanical-electrical transducer element and / or the evaluation circuit can be arranged in areas with acceptable temperatures.
• the components of the device described above can be optimized such that the measurement signal is not affected by mechanical and / or thermal influences.
• temperature influences and / or mechanical influences which could occur, for example, by the conductor rails, can be minimized by the embodiment according to the invention described above.
• FIG. 1 shows an embodiment of an inventive device for detecting a combustion chamber pressure of an internal combustion engine.
• the device 1 10 for detecting a combustion chamber pressure of an internal combustion engine is shown, which can be used in particular in a gasoline engine or gasoline engine.
• the device 1 10 comprises a multi-part housing 1 12, with a base body 1 14 and designed as a sealing cone housing 116 sealing housing 1 18, with a combustion chamber side sealing cone 120.
• the main body 1 14, which for example made of a plastic material and / or a ceramic material can be, picks up a contacting module 122.
• signals of the device 1 10 can be already completely or partially processed and / or forwarded via one or more not shown in Figure 1 interfaces to the outside.
• Attached to the main body is the substantially cylindrically shaped sealing housing 1 18, which in turn concentrically a sensor housing
• This sensor housing 124 encloses.
• This sensor housing 124 has on its combustion chamber 126 side facing an opening 128 which is closed by a membrane 130.
• This membrane 130 is adapted to deform when a pressure is exerted from the combustion chamber 126 in a direction of an axis 132 of the device 110.
• a compensation body 134 is connected to the diaphragm 130 along the axis 132. In turn, this is adjoined in the axial direction by a heat insulation insulator 136, which extends on a first contact region, which extends otherwise perpendicularly to the axis 132, and which is otherwise located in the
• a piezoelectric quartz 144 can basically, alternatively or in addition to a quartz with piezoelectric properties, be understood to mean any piezoelectric material.
• a second contact portion 146 which is formed as extending substantially perpendicular to the axis 132 extending portion of an otherwise preferably substantially parallel to the axis 132 extending second Stromschiende 148 , The two contact areas 138 and 146 form contacts and / or electrodes of the piezoelectric
• electrodes of the piezoelectric quartz 144 may also be configured in other ways and / or as separate from the bus bars 140, 148 components.
• Quartz 144 connects to the second contact region 146 an insulating 150 at.
• the insulating body 150 has a combustion chamber-side portion 152 of reduced diameter, which, together with the piezoelectric quartz 144 and the thermal insulation insulator 136, is enclosed by a sensor holder 154.
• a fixation 156 in the form of a metallic ring adjoins the insulating body in the axial direction on the side facing away from the combustion chamber 126. This metallic ring can, as explained below, for example, with the sensor housing 124th be welded.
• the metallic ring of the fixing 156 in turn encloses in the illustrated embodiment an insulating sleeve 158, via which the fixing 156 is separated from an extension 160 of the insulating body 150.
• the device 110 which is designed as a combustion chamber pressure sensor, protrudes on the membrane side into the combustion chamber 126 of the internal combustion engine. Within the diaphragm 130, the pressure applied in the combustion chamber is converted into a force which acts on the compensation body 134.
• the compensating body 134 has the task of forwarding the force to the thermal insulating body 136, which, together with the compensating body 134, forms a transmission element 162.
• the compensation body 134 has the task of compensating for different thermal expansions of adjacent components.
• the piezoelectric quartz 144 is part of a structure that consists of two parallel transmission paths.
• a first transmission path may include the diaphragm 130, the sensor housing 124, and the fixation 156.
• a second transmission path may include the membrane 130, the compensation body 134, the thermal insulation insulator 136, the first busbar 140 and its first contact region 136, the piezoelectric quartz 144, the second busbar 148 and its second contact region 146, the insulating body 150 and the fixation 156 include.
• the inner second transmission path expands differently than the outer, second transmission path enclosing this differential expansion ultimately leads to an additional loading or unloading of the piezo-quartz 144, which is the force effect resulting from the combustion chamber pressure results, superimposed and can not be distinguished from this in the rule.
• This overlay thus usually leads to a measurement error. Therefore, it is proposed according to the invention to prevent the differential expansion by virtue of the fact that the compensation body 134 is preferably designed with respect to its length and / or its thermal expansion coefficient such that it ensures that the thermal expansion of the inner and outer transmission paths are identical.
• the thermal insulation insulator 136 has the task of interrupting the heat path from the combustion chamber 126 to the piezo-quartz 144, that is to protect the piezo-quartz 144 against overheating.
• this preferably also serves as an electrical insulator, which ensures that the electrical charges transferred from the piezoelectric quartz 144 to the busbars 140, 148 are forwarded only on the path provided for this purpose via the busbars 140, 148 itself.
• the thermal insulation insulator 136 it may be useful or necessary to make the thermal insulation insulator 136 in several parts, and split, for example, in a heat-insulating component and in an electrically insulating component whose materials then for the corresponding Requirements can be optimized.
• the piezoelectric quartz 144 is made of piezoelectric material and converts a force, here the force resulting from the combustion chamber pressure signal, into an electrical charge which is proportional to the applied force, that is, the applied pressure.
• the piezo-quartz 144 converts the force via the detour of a change in length into an electrical charge.
• the electrical charge is, for example, in an evaluation circuit, not shown in Figure 1, which may be wholly or partially included in the contacting module 122, which may alternatively or additionally also be wholly or partially outside the device 110, in one of the charge and / or converted to the force and / or the pressure proportional voltage, which can then be passed to an engine control unit.
• the bus bars 140, 148 each have substantially the same tasks. On the one hand, they transfer the charges which are generated in the piezo-quartz 144 to the evaluation circuit. As can be caused by tension in the busbars 140, 148 itself, which, for example, by thermal expansion or by internal mechanical stresses after welding the busbars with other components in the rear, the combustion chamber 126 facing away from the device 1 10, also a force on the piezoelectric Quartz 144 may arise, which in turn may generate a fault-relevant measurement signal, the busbars preferably have a strain relief function. The busbars can accordingly, in particular in the region between the insulating body 150 and the fixing 156, have a double impact, which allows a certain flexibility in the sensor longitudinal direction, ie along the axis 132.
• the bus bars 140, 148 for example, as described above, in the manner of a corrugated cardboard be designed.
• the busbars 140, 148 also have one or more kinks and / or bends, which serve as spring elements and can ensure the described strain relief.
• the busbars 140, 148 may be designed to be resilient, ie have an elastic effect in the direction of the axis 132.
• Insulating body 150 which may be made of, for example, a ceramic material and / or a plastic material, has the primary function of electrically isolating piezoelectric quartz 144 and one or both of bus bars 140, 148, such as second bus bar 148, from adjacent components , Furthermore, the insulating body 150 provides space for the busbars 140, 148, so that they to
• the insulator 150 preferably also provides space for strain relief strikes 164 and / or other types of spring members of the bus bars 140, 148 to achieve the strain relief effect described above.
• the fixation 156 which is designed, for example, as a metallic fixation, serves as an abutment for the previously described second transmission path, ie the inner force path. It is preferably welded to the sensor housing 124 in the first transmission path, that is to say the outer force path. The welding can be carried out, for example, by using a pre-tension, which may be necessary so that in each operating state all components lie securely and firmly on top of each other. In addition, such a bias voltage for the operation of the piezo-quartz 144 may be required.
• the insulating sleeve 158 serves to avoid an electrical short circuit between the busbars 140, 148 and the fixing 156, even under high mechanical loads during use of the device 110, for example mechanical shocks.
• the first transmission path that is to say the outer force path, likewise begins with the above-described membrane 130 which, for example, can be welded to the sensor housing 124 in the region of the opening 128.
• the sensor housing 124 serves as Carrier components of the second transmission path, so the inner force path, as well as to protect it from external mechanical influences.
• the rear end of the sensor housing 124 is, as shown above, preferably welded to the fixation 156. Between the sensor housing 124 and the inner force path of the sensor holder 154 is arranged. This can, for example, completely or partially off
• Plastic, ceramic, polyceramic or the like for example, as a one-piece, sleeve-shaped part. It may further be configured to receive the piezoelectric quartz 144, the busbars 140, 148, the thermal insulation insulating body 136 and the insulating body 150, and to electrically isolate them from the sensor housing 124.
• the sensor housing 124 encloses the inner force path and, since the diaphragm 130 and the fixation 156 are welded to the sensor housing 124, in conjunction with the inner and outer force paths, form an independent assembly that incorporates the full sensor function and could theoretically function as a separate sensor ,
• This sensor-functional module is added in this embodiment, still in the sealing housing 1 18, for example, welded into the sealing cone housing 116.
• a structure can be achieved, which can be screwed by a user in a cylinder head. When screwing in, high torques (bolting moments) and high axial preloads arise.
• the sensor function assembly is preferably welded only at one point circumferentially in the sealing cone housing 116. A transmission of axial preload forces or torques on the sensor function module is thus preferably largely excluded.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Measuring Fluid Pressure (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=42269723

Family Applications (1)

Country Status (5)

Families Citing this family (9)

Citations (1)

Family Cites Families (14)

• 2009
  • 2009-05-25 DE DE102009026436A patent/DE102009026436A1/de not_active Withdrawn
• 2010
  • 2010-03-22 EP EP10709555A patent/EP2435811A1/de not_active Withdrawn
  • 2010-03-22 WO PCT/EP2010/053672 patent/WO2010136229A1/de active Application Filing
  • 2010-03-22 JP JP2012512264A patent/JP2012527632A/ja active Pending
  • 2010-03-22 US US13/320,835 patent/US20120234084A1/en not_active Abandoned

Patent Citations (1)

Also Published As

Similar Documents

Legal Events