PRESSURE CONTROL VALVE FOR A FUEL INJECTION SYSTEM

Abstract

 A Pressure control valve (10) for a fuel injection system comprises a housing (26) including: a fluid channel (42) extending between an inlet port (44) and an outlet port (46), a valve seat (48) in said fluid channel, and a valve element (50) associated with the valve seat to open or close fluid flow therethrough. The housing includes a base housing part (26.2) and a front housing part (26.1) configured to be engaged into a cavity (12) of a fuel system, said front housing part extending along a longitudinal axis (X), said housing further including fastening means (41) for fixing of the valve into the cavity (12). The inlet port is located in the front housing part and the front housing part has an external, annular contact surface (54) that is adapted to be pressed against a corresponding annular sealing surface (56) in the cavity (12); the annular contact surface separating the region of the inlet port from that of the outlet port. A piezoresistive element (52, 152) is arranged on the annular contact surface (54) for sensing a contact pressure when the valve is mounted in the cavity and presses against the annular sealing surface (56) of the cavity.

Description

Technical field

[0001] The present invention generally relates to the field of fuel injection systems for internal combustion engines, and more specifically to a pressure control valve for controlling a flow of fuel in such system.

Background of the Invention

[0002] A fuel injection system of an internal combustion engine, particularly in a Diesel engine, commonly comprises a high pressure fuel pump feeding a high pressure fuel accumulator, also called common rail, with fuel from the fuel tank. The high pressure fuel is distributed from the fuel accumulator to a plurality of solenoid actuated fuel injectors.

[0003] To ensure good functioning of the motor and also for safety reasons, the pressure inside the common rail is monitored and regulated. The injection system is therefore usually equipped with a pressure control valve and a pressure sensor that are mounted in end cavities of the common rail body.

[0004] The high pressure valve closes the extremity of the high pressure chamber of the common rail. The high pressure valve may be a pressure limiting valve. It comprises a pressure relief valve mounted in a fluid passage extending between an inlet at the front of the valve housing, in communication with the high pressure fluid in the common rail chamber; and an outlet in the lateral housing wall opening in the end cavity of the common rail, in communication with a low pressure fuel return circuit. Such high pressure valve acts as safety valve for maintaining the pressure inside the common rail at less than a prescribed value.

[0005] The pressure control valve is mounted by screwing inside the receiving cavity in the common rail and is therefore provided with an external thread that engages a corresponding thread in the lateral cavity wall. During screwing, the front side of the pressure control valve comes into abutment against the cavity end face. In fact, the contact between the front end of the pressure control valve and the bottom face of the cavity will form a fluid-tight separation between the high and low pressure sides. It is thus of importance to properly control the screwing process of the pressure control valve into the cavity to ensure that a proper pressure force exists at the interface between both parts, able to provide a sealed barrier even at high fuel pressures (up to 3000 bars). The screwing force is generally checked by means of a torque wrench.

Object of the invention

[0006] An object of the present invention is to provide an improved way of checking the screwing force of a pressure control valve in such fuel injection system.

General Description of the Invention

[0007] The present invention proposes a pressure control valve for controlling a flow of fuel in an injection system. The pressure control valve has a housing including: a fluid channel extending between an inlet port and an outlet port, a valve seat in the fluid channel, and a valve element associated with the valve seat to open or close fluid flow therethrough. The housing has a base housing part and a front housing part, the latter being configured to be engaged into a cavity of a fuel system. The front housing part extends along a longitudinal axis and comprises an outer thread that cooperates with a corresponding thread in the cavity for fixing the valve therein by screwing in the longitudinal axis direction. The inlet port is located in the front housing part. The front housing part has an external, annular contact surface that is adapted to be pressed against a corresponding annular sealing surface in the cavity, whereby the annular contact surface separates (seen in the longitudinal axis direction) the region of the inlet port from that of the outlet port.

[0008] According to an important aspect of the invention, a piezo-resistive element is arranged on the annular contact surface for sensing a contact pressure when the valve is mounted in the cavity and presses against the annular sealing surface of the cavity.

[0009] The inventive pressure control valve thus includes a pressure transducer/sensor formed by a piezo-resistive element that is configured for sensing the pressure exterted by the control valve against the cavity in which it is mounted. As is known, the resistance of a piezo-resistive element varies with the mechanical strain applied to it. The knowlegde of the contact pressure between the control valve and the cavity can thus be simply determined by evaluating the measurement signal generated by the piezo-resistive element based on conventional resistance measurement.

[0010] At installation of the pressure control valve in the cavity, the force applied to the piezo-resistive element will depend on the screwing torque exerted on the pressure control valve. Evaluating the voltage signal of the piezo-resistive element will permit to easily determine the contact pressure exerted by the pressure control valve in the component in which it is mounted. The sensor voltage signal V can be expressed as V=f(P), where P is the pressure force (here compression due to screwing) exerted onto the piezo-resistive element. For piezo-resistive materials, the resistance change with pressure can be substantially linear.

[0011] In use, when the pressure control valve is in fluid communication with an associated high pressure component, the piezo-resistive element permits determining the level of fuel pressure inside the high pressure component. Indeed, the fuel pressure acting on the front side of the pressure control valve exerts a force that is opposite to the screwing force, thus reliveing part of the pressure exerted by the pressure control valve onto its receiving cavity. When the fuel pressure increases, the contact pressure between the pressure control valve and the cavity decreases, and so does the force applied onto the piezo-resistive element. In other words, the contact pressure existing at the interface between the pressure control valve and the cavity depends on the fuel pressure and can be easily determined based on the voltage signal across the piezo-resistive element.

[0012] The present invention is thus simple to implement and does not interfer with the general design of the pressure control valve. It can thus be used with a variety of valve designs, passive or active.

[0013] In practice, an electrical link is provided in the housing to apply a voltage to the piezo-resistive element, in particular from a connector terminal. It thus suffices to provide one electric wire or path in the valve to be able to measure the resitance of the piezo-resistive element, which is already at groud potentional due to direct contact with the cavity.

[0014] A peripheral insulating sheeting or coating is advantageously provided on the outer surface of said housing that is to be engaged in said cavity.

[0015] The piezo-resistive element may be piezo-resistive film or coating that is applied to the annular contact surface of the pressure control valve. Any kind of piezo-resistive element having a resistance depending on the force applied thereo can be used.

[0016] Preferably, the housing comprises one or more surfaces circumscribed by said annular contact surface that are oriented transversal to said longitudinal axis and in contact with the fluid pressure.

[0017] Advantageously, the inlet port is located in a front end face of the front housing part and the annular contact surface is part of the front end face and surrounds said inlet port. Such case, the piezo-resistive element is thus arranged at the front end of the pressure control valve, by which it presses against the cavity bottom.

[0018] In embodiments, the housing may generally comprise a cylindrical housing body with an internal cavity that is closed at the front end by a seat ring. The seat ring has an inner side turned towards the internal cavity and an opposite outer side forming the front end face. The inlet port and valve seat are arranged in the seat ring, an inlet section of the fluid passage extending in the seat ring between the inlet port and the valve seat.

[0019] The pressure control function of the valve itself may follow various designs, being active or passive.

[0020] A passive pressure control valve is e.g. a pressure limiting valve. In such embodiment, the valve member may be typically biased on the valve seat by a compression spring. Preferably, the compression spring acts upon an axially guided piston, which in turn acts upon said valve member.

[0021] An example of active valve control is the so-called high pressure valve. In such case the valve includes an electromagnetic actuator (solenoid). A pin is axially moveable in the internal cavity, the pin being coupled at one end to the valve member and at the other end attached to an armature. It further includes an electromagnet adapted to create a magnetic field to move the armature in a first direction. A compression spring, preferably acting on the armature, to move the pin in a second direction opposite the first direction. Genrally the pin is biased in the closing direction.

[0022] In embodiments, the housing comprises an outer thread that cooperates with a corresponding thread in said cavity for fixing the valve therein by screwing in the longitudinal axis direction.

[0023] According to another aspect, the invention concerns a fuel injection component for a fuel injection system, the fuel injection comprising a high pressure reservoir, which, in use, is subjected to fuel at high pressure, wherein

• The component is assigned the pressure control valve according to the present invention, which is disposed in a cavity in the component between a high pressure side and a low pressure side;
• The cavity comprises a cylindrical wall, a bottom wall, a high pressure inlet port in a bottom region of the cavity and a low pressure outlet port;
• The pressure control valve is fixedly mounted with its front housing region in said cavity and has its front annular contact surface pressing against an annular sealing surface of the cavity, the piezo-resistive element being sandwiched between the surfaces.

[0024] In embodiments, fuel injection component comprises one or more of the following features:

• the high pressure inlet port centrally opens into the bottom cavity;
• the annular sealing surface is part of the cavity bottom and surrounds the inlet port;
• the inlet port opens in the front side and is surrounded by the annular contact surface;
• the front side comprises one or more surfaces circumscribed by the annular contact surface that are oriented transversally, preferably perpendicularly, to the longitudinal axis and in direct contact with the pressurized fluid;
• the valve housing comprises an external thread that engages a cooperating thread in the wall surface of the cavity.

[0025] The invention is applicable to various fuel system componsents, for pressure regulation between high and low pressures sides. In particular the present pressure control valve can be assigned to a common rail or a fuel pump.

Brief Description of the Drawings

[0026] Further details and advantages of the present invention will be apparent from the following detailed description of not limiting embodiments with reference to the attached drawings, wherein:

Fig. 1

is a cross-section view through a pressure control valve according to first embodiment of the invention;

Fig. 2

is a cross-section view of a pressure control valve according to a second embodiment of the invention;

Fig. 3

is a graph (voltage vs. time) showing the response of a piezoresistive element at different rail pressures.

Description of Preferred Embodiments

[0027] In the description below, the terms "top, bottom, above, below" will be used with reference to the orientation in the figures for ease of explanation.

[0028] Two embodiments of the present pressure control valve will now be described in applications where they are used for pressure regulation in a fuel accumulator (or common rail) of an injection system for an internal combustion engine, in particular a diesel engine.

[0029] Turning to Fig.1, there is shown a first embodiment of the present pressure control valve 10, wherein the valve is assigned to a common rail and is designed as pressure limiting valve.

[0030] Although not entirely shown, a common rail conventionally comprises an elongated tubular body and a longitudinal through bore defining an inner volume receiving, in use, high pressure fuel. The body is provided with a cavity at both extremities that are in fluid communication with the longitudinal bore. Externally, the rail is conventionally provided with protrusions distributed along the length of the rail body between the extremities. Each of the protrusions has a radially extending high pressure channel, not shown, adapted to flow high pressure fuel either entering the rail or exiting the rail towards fuel injectors.

[0031] Reference sign 12 in Fig.1 designates such a cavity at one end of a common rail 14. The cavity 12 is cylindrical and comprises a lateral wall 16 and a bottom face 18. The upper region of cavity 12 is provided with a threaded section 20 for screwing the pressure control valve 10 therein. A channel 22 opens laterally in the lower cavity region to provide a return flow path from the cavity to the low pressure circuit of the injection system. An orifice 24 is arranged in the bottom face 16 to enable fluid communication with the longitudinal through bore 15 of the common rail, which is filled in use with high-pressure fuel. It may be noted here that in the shown embodiment, reference sign 15 designates a transition bore that opens at one end into the cavity through orifice 24, and at the other is in communication with the longitudinal through bore (not represented). Typically such transition bore 15 has a diameter lower than the longitudinal bore. Alternatively, the longitudinal through bore of the common rail could open directly into the cavity.

[0032] Turning now pressure control valve 10 itself, it comprises a housing 26 with a front region 26.1, engaged into cavity 12 and a base region 26.2. Housing 26 includes a metallic, cylindrical housing body 28 that extends along a longitudinal axis A and comprises an internal cavity 30, which is closed towards the base region 26.2. A compression spring 29 and a piston 31 are arranged inside the cavity 30. Towards the front region, internal cavity 30 is closed by a seat ring 32. The seat ring has a disk-like body portion 34 with a narrower cylindrical extension 36. The body portion 34 fits in an inlet section of the housing body 28 and rests, with its annular inner side 38 against a shoulder 39 of the body 28. The cylindrical extension 36 of seat ring 32 extends further inside cavity 12. The body portion 34 of seat ring 32 has a front side 40, opposite inner side 38 that forms the end face of the pressure control valve 10. The seat ring 32 is fixed in place in the housing body 28. It is e.g. maintained by the peripheral edge of body 28.

[0033] In use, the control valve is positioned with the front region 26.2 screwed in cavity 12, the front side 40 being pressed against the bottom face 18 of cavity 12. An outer thread 41 is provided at the outer periphery of the front housing region 26.1, proximal to the base portion. The pressure exerted by the front side 40 onto the cavity bottom 18 depends on the screwing torque applied by means of the cooperating threads 20 and 41. The base portion may comprise a male or female drive configuration, here e.g. a socket head 43 for a Torx wrench (but other shapes can be used).

[0034] The pressure control function is achieved by way of a check valve formed in a fluid passage 42 provided in the housing 26. The fluid passage 42 extends from an inlet port 44, centrally arranged in front side 40, to a pair of outlet ports 46 located in the housing body 28 and thus opening radially/laterally into the cavity 12. The cavity 12 is sealed from the exterior by a seal ring 37.

[0035] A valve seat 48 is arranged in the fluid passage 42, namely at the inner end of an inlet section 42.1 of the fluid passage 42 opening in the inner end face of the cylindrical extension 36. The valve seat 48 is formed as an annular sealing surface surrounding the end of inlet section 42.1 and has a spherical cross-section, although other shapes are possible.

[0036] Reference sign 50 designates a ball-shaped valve element that cooperates with valve seat 48 to control the flow through the latter. Accordingly, valve seat 48 is moveable between a closed position, shown in Fig.1, wherein it sealingly rests on the valve seat 48 and impedes the flow of fluid downstream thereof, and an open position in which the valve element is off the seat and allows fluid flow therethrough. The valve member is biased in the closed position by the compression spring 29 via piston 31. Spring 29 has a predetermined spring force that its chosen so that the valve element 50 lifts from its seat 48 when the fuel pressure in fluid passage 42 exceeds a predetermined pressure threshold, acting as safety feature to relieve the excess fuel pressure from the fuel rail. The general design and operation of such pressure limiting valve is known in the art and need not be described in further details.

[0037] It shall be appreciated that a piezo-resistive element 52 is arranged on the front side 40 of the seat ring for sensing a contact pressure when the presure control valve is mounted in the cavity 12 and presses against the bottom face 18 thereof.

[0038] More specifically, in the mounted position, a part of the front side 40, referred to as annular contact surface 54, presses against a corresponding portion of the bottom face 18, referred to as annular sealing surface 56. This forms an annular barrier preventing fluid flow along the front side 40 towards the cavity interior. The efficiency of the seal provided by the barrier depends on the screwing strength.

[0039] The piezo-resistive element 52 is advantageously arranged to be sandwiched between the corresponding annular surfaces 54 and 56 of the seat ring 32 and of the bottom face 18, respectively. An electrical link is provided in the valve 10 to apply a predetermined voltage to the piezo-resistive element 52, whereas the lower side of the piezo-resistive element is in contact with the bottom face 18 of the common rail cavity, which is at ground potential. Such electrical link can be provided by an insulated wire, schematically indicated 58 in Fig.1, drawn through the housing, e.g. though the housing body 28, and having one end connected to the piezo-resistive element 52, whereas the opposite end connects a contact terminal in a connector portion 60.

[0040] The provision of the piezo-resistive element 52 at this interface allows measuring the contact pressure between the seat ring 32, respectively the pressure control valve 10, and the bottom face 18. This piezo-resistive element 52 can thus be used for measuring the initial screwing force in the fuel rail cavity 12 as well as for monitoring the fuel pressure inside the common rail.

[0041] As it will be understood by those skilled in the art, proper operation of the pressure regulating valve 10 needs a fluid-tight separation between the inlet port 44 and outlet port 46, which is here provided by the cooperating annular sealing surfaces 54 and 56. This thus requires that an appropriate screwing torque is applied at mounting, in particular in consideration of the high fuel pressures inside the common rail.

[0042] The benefit of the piezo-resistive element 52 is thus to generate a measure signal that depends on the contact force between the valve 10 and the cavity 12.

[0043] Also, in use, the contact pressure will vary depending on the fuel pressure in the common rail (in the longitudinal through bore). Indeed, the fuel pressure exerts a force on the pressure control valve 10, which has an axial component along axis X, which is also the screwing direction. When the fuel pressure increases, the force exerted by the fuel on the valve 10 also increases, and the contact pressure decreases correspondingly. The increase of pressure in the fuel rail thus causes a decrease of the contact pressure that can be monitored by means of the piezo element 52, the internal resistance of which decreases when an increasing compressive force is applied.

[0044] The relevant surfaces impacting, in this embodiment, the contact pressure are surfaces of the pressure control valve exposed to the fluid and extending transversally to the longitudinal axis X. One can notice here the annular surface 62 circumscribed by the contact surface 54 and delimited internally by the inlet orifice 44.

[0045] The piezo-resistive element 52 may typically be a piezo-resistive film or coating that is applied onto the contact surface 54 at the front of the seat ring 32. It can be single or multi-layered. Any kind of appropriate piezo-resistive technology can be used, allowing to measurement of contact forces/pressures applied thereon. Such force-sensing piezo electric films are known in the art. One example is a hydrocarbon film known as DiaForce® and developed by the Fraunhofer Institute for Manufacturing Technology and Advanced Materials (Brement, Germany).

[0046] With such piezo-resistive pressure sensor able to measure static forces one can thus determine, by way of the measure of the voltage through the piezo-resistive element 52, the contact force at the interface between the control pressure valve 10 and bottom face 18 of the cavity 12. To avoid short-circuits, the housing 26 is advantageously electrically insulated. This can be done by providing an insulating sheeting or coating 64 on the external surface of housing 26, or on the cylindrical cavity wall 16.

[0047] Fig. 3 shows a graph (voltage vs. time) illustrating the response of the piezo element for several fuel rail pressures. The piezo element has a known resistance when its is not subject to any compressive force; and its resistance decreases when a compressive force is applied thereto. When reading Fig.3, one must keep in mind that when the fuel rail pressure increases, the contact pressure decreases, i.e. the compressive force on the piezo element decreases. As can be observed from Fig.3, the change of resistance due to the change of fuel rail pressure does indeed lead to a significant change of voltage that can be properly detected, occuring over several volts for the pressure range of about 2200 bars. Since the resistance of the piezo element increases due to the reduction of pressure thereon, the voltage signal also increases.

[0048] Fig.2 shows in cross-section a second embodiment, wherein the pressure control valve 110 is designed as a so-called high pressure valve including a solenoid valve for regulating the pressure in the common rail. The general construction of the valve housing is similar to that of Fig.1, but it here hence contains a solenoid actuator for controlling the valve element. Same or similar elements are indicated by same reference signs, augmented by 100.

[0049] On the figure one will recognise the housing 126 with its base 126.2 and front 126.1 regions. The cavity 112 in the common rail end face here has a broadened inlet section 112.1. The front region 126.1 has a cylidrical shape with an enlarged section 26.11 adjacent the base portion 126.2 to match the diameter of the inlet section 112.1. An outer thread 141 is provided at the peripheraly of the enlarged section 126.11, which engages a corresponding thread 120 on the lateral wall of the inlet section 126.11 of cavity 12.

[0050] Housing 126 includes a metallic, cylindrical housing body 128 that extends along a longitudinal axis A and includes an internal bore 130. Towards the front region, bore 130 is closed by a seat ring 132 having a disk-like body portion 134 with a narrower cylindrical extension 136. The body portion 134 fits in an inlet section of the housing body an rests, with its annular inner side 138 against a shoulder 139 of the body 28. The front side 140 of the seat ring 132, opposite inner side 138, forms the end face of the pressure control valve 10. In use, the control valve is positioned with the front region 126.2 screwed in cavity 12, the front side 40 being pressed against the bottom face 18 of cavity 12. The screwing torque applied on the cooperating threads 120 and 140 determines the contact pressure at the front side 140.

[0051] The pressure regulating function is achieved here by way of a control valve formed in a fluid passage 142 provided in the housing 126, with an associated valve actuator. The fluid passage 142 extends from an inlet port 144, centrally arranged in front side 140, to a pair of outlet ports 146 located in the housing body 128 and thus opening radially/laterally into the cavity 112.

[0052] A valve seat 148 is arranged in the fluid passage 142, namely at the inner end of an inlet section of the fluid passage 142 opening in the inner end face of the cylindrical extension 136. The valve seat 148 is formed as an annular sealing surface surrounding the end of inlet section and has a spherical cross-section, although other shapes are possible.

[0053] A ball-shaped valve element 150 cooperates with valve seat 48 to control the flow through the latter. Reference sign 170 designates an armature pin attached at one end (at the base region) to an armature 172. The armature pin 170 is axially guided in cylindrical cavity 130 and biased in direction of the valve seat by spring 129. The other end of armature pin 172 is thus in contact with valve member 150 and presses it against valve seat 148. The armature pin 170 can be moved in the axial direction towards the base portion by energizing coils 174 forming an electromagnet. This internal housing design is well known and will not be further detailed.

[0054] Similar to Fig.1, the piezo-resistive element 152 is arranged on the front side 140 of the seat ring 132 for sensing a contact pressure when the presure control valve 110 is mounted in cavity 112 and presses against the bottom face 118. Here again, the piezo-resistive element 152 allows measuring the screwing force of the pressure concrol valve in the cavity, as well as the pressure level inside the fuel rail.

Claims

1. Pressure control valve (10, 110) for a fuel injection system, said valve comprising:

a housing (26, 126) including: a fluid channel (42, 142) extending between an inlet port (44, 144) and an outlet port (46, 146), a valve seat (48, 148) in said fluid channel, and a valve element (50, 150) associated with said valve seat to open or close fluid flow therethrough;

wherein said housing includes a base housing part (26.2, 126.2) and a front housing part (26.1, 126.1) configured to be engaged into a cavity (12, 112) of a fuel system, said front housing part extending along a longitudinal axis (X), said housing further including fastening means (41, 141) for fixing of the valve into said cavity (12, 112);

wherein said inlet port is located in said front housing part and said front housing part has an external, annular contact surface (54, 154) that is adapted to be pressed against a corresponding annular sealing surface (56, 156) in said cavity (12, 112), said annular contact surface separating the region of the inlet port from that of the outlet port;

wherein a piezo-resistive element (52, 152) is arranged on said annular contact surface (54) for sensing a contact pressure when said valve is mounted in said cavity and presses against said annular sealing surface (56) of said cavity.

2. Pressure control valve according to claim 1, wherein an electrical link (58, 158) is provided in said housing to apply a voltage to said piezo-resistive element, in particular from a connector terminal.

3. Pressure control valve according to claim 1 or 2, wherein said piezo-resistive element (52) is a piezo-resistive film or coating applied to said annular contact surface.

4. Pressure control valve according to any one of the preceding claims, wherein said housing comprises one or more surfaces (62) circumscribed by said annular contact surface that are oriented transversal to said longitudinal axis and in contact with the fluid pressure.

5. Pressure control valve according to any one of the preceding claims, wherein
said inlet port (44) is located in a front end face (40) of said front housing part; and
said annular contact surface (54) is part of said front end face and surrounds said inlet port (44).

6. Pressure control valve according to any one of the preceding claims, wherein
said housing comprises a cylindrical housing body (28, 128) with an internal cavity (30, 130) that is closed at said front end by a seat ring (32, 132, said seat ring having an inner side (38, 138) turned towards said internal cavity and an opposite outer side forming said front end face (40, 140), and
said inlet port and valve seat are arranged in said seat ring, an inlet section (42.1) of said fluid passage extending in said seat ring between said inlet port and valve seat.

7. Pressure control valve according to claim 6, wherein said valve member (50) is biased on said valve seat (48) by a compression spring (29), and preferably, said compression spring acts upon an axially guided piston (31), which in turn acts upon said valve member (50).

8. Pressure control valve according to claim 6, comprising an electromagnetic actuator including:

a pin (170) axially moveable in said cavity (130), said pin being coupled at one end to said valve member (150) and at the other end attached to an armature (172);

an electromagnet (174) adapted to create a magnetic field to move said armature in a first direction; and

a compression spring (129), preferably acting on said armature, to move said pin in a second direction opposite said first direction.

9. Pressure control valve according to any one of the preceding claims, wherein a peripheral insulating sheeting or coating (64, 164) is provided on the outer surface of said housing that is to be engaged in said cavity.

10. Pressure control valve according to any one of the preceding claims, wherein said housing comprises an outer thread (41, 141) that cooperates with a corresponding thread (20, 120) in said cavity for fixing said valve therein by screwing in said longitudinal direction.

11. A fuel injection component for a fuel injection system, said fuel injection comprising a high pressure reservoir, which, in use, is subjected to fuel at high pressure, wherein
said component is assigned a pressure control valve according to any one of the preceding claims, which is disposed in a cavity in said component between a high pressure side and a low pressure side,
said cavity comprises a cylindrical wall, a bottom wall, a high pressure inlet port in a bottom region of said cavity and a low pressure outlet port;
wherein said pressure control valve is fixedly mounted with its front housing region in said cavity and has its front annular contact surface pressing against an annular sealing surface of said cavity, said piezo-resistive element being sandwiched between said surfaces.

12. The component according to claim 11, wherein
said high pressure inlet port centrally opens into said bottom cavity;
said annular sealing surface is part of said cavity bottom and surrounds said inlet port;
said inlet port opens in said front side and is surrounded by said annular contact surface; and
said front side comprises one or more surfaces circumscribed by said annular contact surface that are oriented transversally, preferably perpendicularly, to said longitudinal axis and in direct contact with the pressurized fluid.

13. The component according to claim 11 or 12, wherein said valve housing comprises an external thread that engages a cooperating thread in said wall surface of said cavity.

14. The component according to claim 11, 12 or 13, wherein said component is a common rail or a fuel pump.

Drawing