Pressure sensor for vehicle and pressure measurement method

Abstract

The present invention provides a pressure sensor for a vehicle and a pressure measurement method, which have low measurement cost and high measurement accuracy. The pressure sensor includes a housing and a base arranged in the housing, a first sensing element, a second sensing element and a pressure signal processing device, the first sensing element, the second sensing element and the pressure signal processing device are all arranged on the base, and the pressure signal processing device is connected to the first sensing element and the second sensing element respectively. The pressure measurement method includes: sensing the pressure difference of the gas between the upstream and downstream of the engine particulate trap through the first sensing element, and feeding back the pressure difference information of the gas to the pressure signal processing device; sensing the absolute pressure of the gas at the downstream of the engine particulate trap through the second sensing element, and feeding back the absolute pressure information to the pressure signal processing device; the pressure signal processing device processes the received pressure difference information and absolute pressure information of the gas, so that the pressure difference information and the absolute pressure information can be output through one signal.

Description

Technical Field

[0001] The present invention relates to the field of automobile technology, and in particular to a pressure sensor and a pressure measurement method. Background Art

[0002] In order to meet the limit requirements of new emission regulations on PM (particulate matter emissions), a currently known technical solution is to install a gasoline engine particulate filter (GPF: Gasoline Particulate Filter) on the exhaust pipe of the gasoline engine.

[0003] Although GPF can effectively capture particulate matter in automobile exhaust, as the amount of captured particulate matter increases, the exhaust pressure will increase, affecting the engine's power and economy. Therefore, when the particles in the GPF accumulate to a certain level, it is necessary to increase the engine exhaust temperature to oxidize and burn the particulate matter in the GPF, that is, GPF regeneration. Furthermore, in order to trigger the regeneration of the GPF and meet the requirements of the on-board diagnostic system (OBD), it is necessary to accurately measure the pressure difference between the upstream and downstream of the GPF. In addition, in order to monitor the status of the GPF connecting pipeline and meet the OBD diagnostic requirements, it is also necessary to measure the absolute pressure downstream of the GPF.

[0004] In order to meet the above measurement requirements, one of the currently known solutions is to use two pressure sensors, one of which measures the pressure difference between the upstream and downstream of the GPF, and the other measures the absolute pressure downstream of the GPF. However, the disadvantage of this solution is that it requires two sets of pressure sensors and multiple connecting pipes, and also requires the use of two ECU interfaces, which significantly increases the system cost. Another solution is to use two pressure sensing modules in the same pressure sensor to measure the absolute pressure upstream and downstream of the GPF respectively, and feed back the two absolute pressure signals to the ECU. Obviously, in the second solution, additional calculations are required by the ECU to obtain the desired pressure difference between the upstream and downstream of the GPF, and the error of this calculation is the accumulation of the measurement errors of the two pressure sensing modules separately. Therefore, the accuracy of the pressure difference is low and cannot meet the OBD diagnostic requirements. Summary of the invention

[0005] In view of this, the present invention provides a pressure sensor and a pressure measurement method for a vehicle, which can directly measure the pressure difference between the upstream and downstream of the engine particulate filter without calculation, and does not need to configure too many connecting pipes. At the same time, only one ECU interface is required. Therefore, the system cost is low and the measurement accuracy is high.

[0006] According to one aspect of the present invention, there is provided a pressure sensor for a vehicle, comprising a housing and a base arranged in the housing, a first sensing element, a second sensing element and a pressure signal processing device, wherein the first sensing element, the second sensing element and the pressure signal processing device are all arranged on the base, and the pressure signal processing device is connected to the first sensing element and the second sensing element respectively;

[0007] Among them, the first sensing element is used to sense the pressure difference of the gas between the upstream and downstream of the engine particulate filter, and feed back the pressure difference information of the gas to the pressure signal processing device; the second sensing element is used to sense the absolute pressure of the gas downstream of the engine particulate filter, and feed back the absolute pressure information to the pressure signal processing device; the pressure signal processing device is used to process the received pressure difference information and absolute pressure information of the gas so that the pressure difference information and the absolute pressure information can be output through one signal.

[0008] Furthermore, the housing is provided with a first chamber and a second chamber isolated from each other, and is also provided with a third chamber communicating with the second chamber; the first sensing element and the second sensing element both have two opposite surfaces;

[0009] One surface of the first sensing element is in the first chamber, and the other surface is in the third chamber; one surface of the second sensing element is in the second chamber, and the other surface is in a vacuum environment.

[0010] Furthermore, a fourth chamber isolated from other chambers is provided in the shell, and the pressure signal processing device is provided in the fourth chamber.

[0011] Furthermore, the first chamber and the third chamber are arranged opposite to each other and are arranged on the same side of the base as the second chamber, and the third chamber and the fourth chamber are arranged on the other side of the base.

[0012] Furthermore, a first pipeline and a second pipeline are provided on one side of the shell, the first pipeline is used to introduce gas upstream of the engine particulate filter, and the second pipeline is used to introduce gas downstream of the engine particulate filter.

[0013] Furthermore, the housing has a first side and a second side that are arranged opposite to each other, the first side is provided with a mounting flange for fixing the pressure sensor on a vehicle, and the second side is provided with a connection port for connecting to an external mechanism.

[0014] Furthermore, the first side and the second side are arranged on the bottom of the housing, and a positioning rod for positioning the pressure sensor on the vehicle is provided on the bottom.

[0015] Furthermore, the shell includes a main body and a cover plate arranged at an opening of the main body.

[0016] Furthermore, the base is connected to the body and the cover plate through silicone sealing.

[0017] Further, the pressure signal processing device includes a circuit board and a digital application specific integrated circuit arranged on the circuit board;

[0018] The digital application specific integrated circuit is used to simultaneously perform nonlinear and temperature drift compensation processing on the pressure difference information input by the first sensing element and the absolute pressure information input by the second sensing element, and encode the processed pressure difference information and absolute pressure information so that the pressure difference information and the absolute pressure information can realize one signal output using a single-sided half-byte digital communication protocol.

[0019] Furthermore, the first sensing element and the second sensing element both include a strain gauge and a Wheatstone bridge arranged on the strain gauge; wherein the first sensing element and the second sensing element are respectively connected to four pins through gold binding wires, and the four pins are connected to the pressure signal processing device.

[0020] Furthermore, a protective gel is provided on the gold binding wire, and the protective gel is a fluorine-containing gel.

[0021] Furthermore, both the first sensing element and the second sensing element are MEMS sensing elements.

[0022] Furthermore, the pressure signal processing device is connected to the outside via three pins, one of which is used to transmit the signal.

[0023] Furthermore, the surface of the pin is gold-plated.

[0024] Furthermore, the base is made of epoxy resin modified material.

[0025] According to another aspect of the present invention, there is provided a pressure measurement method for a vehicle, comprising:

[0026] A housing and a base, a first sensing element, a second sensing element and a pressure signal processing device are provided in the housing, wherein the first sensing element, the second sensing element and the pressure signal processing device are all provided on the base, and the pressure signal processing device is connected to the first sensing element and the second sensing element respectively;

[0027] The pressure measurement method further comprises:

[0028] The first sensing element senses the pressure difference of the gas between the upstream and downstream of the engine particulate trap, and feeds back the pressure difference information of the gas to the pressure signal processing device;

[0029] sensing the absolute pressure of the gas downstream of the engine particulate trap through the second sensing element, and feeding back the absolute pressure information to the pressure signal processing device; and

[0030] The pressure signal processing device processes the received pressure difference information and absolute pressure information of the gas so that the pressure difference information and the absolute pressure information can be output through one signal.

[0031] Furthermore, the pressure signal processing device includes a circuit board and a digital application specific integrated circuit arranged on the circuit board, and its operation steps include:

[0032] The digital application specific integrated circuit simultaneously performs nonlinear and temperature drift compensation processing on the pressure difference information input by the first sensing element and the absolute pressure information input by the second sensing element, and encodes the processed pressure difference information and absolute pressure information so that the pressure difference information and the absolute pressure information can realize one signal output using a single-sided half-byte digital communication protocol.

[0033] Furthermore, the housing is provided with a first chamber and a second chamber isolated from each other, and is further provided with a third chamber connected to the second chamber, wherein the step of the first sensing element sensing the pressure difference of the gas between the upstream and downstream of the engine particulate trap comprises:

[0034] The first sensing element senses the pressure of the gas in the first chamber through one surface, and senses the pressure of the gas in the third chamber through another surface, and obtains the pressure upstream and downstream of the engine particulate trap according to the pressure of the gas in the first chamber and the pressure of the gas in the third chamber;

[0035] The step of sensing the absolute pressure of the gas downstream of the engine particulate trap by the second sensing element comprises:

[0036] The second sensing element senses the pressure of the gas in the second chamber through one surface, and senses the vacuum degree of a vacuum environment through another surface thereof, and obtains the absolute pressure downstream of the engine particulate filter based on the pressure of the gas in the second chamber and the vacuum degree.

[0037] In summary, in the pressure sensor and pressure measurement method for vehicles provided by the present invention, it is only necessary to use two sensing elements and a small number of connecting pipes to realize the measurement of the upstream and downstream pressure difference and the downstream absolute pressure of the engine particulate filter, and the information output by the two sensing elements can be processed into a signal suitable for an electrical output through a pressure signal processing device, and then the electrical output can be transmitted to the outside (such as a vehicle controller). Therefore, the electrical output only occupies one external interface, and the system cost is low. Moreover, the desired upstream and downstream pressure difference of the engine particulate filter is directly measured by the first sensing element. Therefore, there is no need to perform additional calculations externally, the measurement error is small, the measurement accuracy is high, and the regeneration of the engine particulate filter can be controlled more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings are used to better understand the present invention and do not constitute an improper limitation of the present invention.

[0039] Figure 1 is an exploded schematic diagram of a pressure sensor in an embodiment of the present invention;

[0040] Figure 2 is a schematic diagram of the assembly of a pressure sensor in an embodiment of the present invention;

[0041] Figure 3 is a schematic diagram of the assembly of a pressure measuring unit in an embodiment of the present invention;

[0042] Figure 4 yes Figure 3 The schematic diagram of the assembly of the pressure measuring unit after flipping 180° is shown;

[0043] Figure 5 is a top view of the main body of the housing in an embodiment of the present invention;

[0044] Figure 6 is a longitudinal cross-sectional view of the pressure sensor in an embodiment of the present invention when the cover plate is removed at a first viewing angle;

[0045] Figure 7 4 is a longitudinal cross-sectional view of the pressure sensor in the embodiment of the present invention when the cover plate is set at a second viewing angle.

[0046] In the figure:

[0047] 1-shell; 11-main body; 110-first side; 120-second side; 130-bottom, 140-third side; 111-mounting flange; 112-connection port; 113-first pipeline; 114-second pipeline; 115-first chamber; 116-second chamber; 117-third chamber; 118-fourth chamber; 12-cover; 2-base; 3-first sensing element; 4-second sensing element; 5-pressure signal processing device; 51-circuit board; 52-digital application specific integrated circuit. DETAILED DESCRIPTION

[0048] In order to make the purpose and features of the present invention more obvious and understandable, the specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. However, the present invention can be implemented in different forms and should not be considered to be limited to the embodiments described. As used in this specification, the singular forms "a", "an" and "the" include plural objects unless the content clearly indicates otherwise.

[0049] Figure 1 is an exploded schematic diagram of a pressure sensor in an embodiment of the present invention, Figure 2 is a schematic diagram of the assembly of a pressure sensor in an embodiment of the present invention, Figure 3 is a schematic diagram of the assembly of a pressure measuring unit in an embodiment of the present invention, Figure 4 yes Figure 3 The pressure measuring unit shown is an assembly diagram after being flipped 180°, and it should be known that Figure 3 and Figure 4 The invisible parts are indicated by dotted lines.

[0050] like Figures 1 to 4 As shown, a pressure sensor comprises a housing 1 and a pressure measuring unit encapsulated in the housing 1. The pressure measuring unit comprises a base 2 and a first sensing element 3, a second sensing element 4 and a pressure signal processing device 5 arranged on the base 2, and the pressure signal processing device 5 is connected to the first sensing element 3 and the second sensing element 4 respectively. The pressure measurement method of the pressure sensor comprises:

[0051] The first sensing element 3 senses the pressure difference of the gas between the upstream and downstream of the gasoline engine particulate filter (GPF), and feeds back the pressure difference information of the gas to the pressure signal processing device 5;

[0052] The absolute pressure of the gas downstream of the gasoline engine particulate trap is sensed by the second sensing element 4, and the absolute pressure information of the gas is fed back to the pressure signal processing device 5;

[0053] The pressure signal processing device 5 processes the received absolute pressure information and pressure difference information of the gas so that the two pieces of information can be output through one signal.

[0054] Here, the pressure sensor is not limited to the gasoline engine particulate filter, but can also be a diesel engine particulate filter. To this end, the pressure sensor of the present invention is mainly used to measure the pressure difference between the upstream and downstream of the particulate filter and the downstream pressure on the vehicle engine exhaust pipe. On the one hand, by obtaining the pressure difference between the upstream and downstream of the engine particulate filter, it can be used to control the regeneration of the engine particulate filter. On the other hand, by obtaining the absolute pressure downstream of the engine particulate filter, it can be used to monitor the state of the connecting pipeline on the engine particulate filter, so as to meet specific requirements such as the vehicle-mounted diagnostic system (OBD).

[0055] Obviously, the pressure sensor of the present invention only needs two pressure sensing elements and a small amount of connecting pipes to realize the measurement of the upstream and downstream pressure difference and the downstream absolute pressure of the engine particulate filter, and the two-way pressure information output by the two sensing elements can be processed into one signal output through the pressure signal processing device 5, and then the one-way signal can be transmitted to the outside, such as to the vehicle controller (Electronic Control Unit: ECU, electronic control unit), so the one-way information only occupies one external interface, and the system cost is low. Moreover, the desired upstream and downstream pressure difference of the engine particulate filter can be directly measured by the first sensing element 3, so there is no need to do additional calculations through the outside, the measurement error is small, the measurement accuracy is high, and the regeneration of the engine particulate filter can be controlled more accurately.

[0056] In this embodiment, the housing 1 may include a main body 11 and a cover plate 12 provided at the opening of the main body 11. The cover plate 12 and the main body 11 together define an installation space to accommodate the pressure measuring unit. In a preferred connection method, the cover plate 12, the main body 11 and the base 2 are connected by glue, so as to achieve a good sealing effect and facilitate assembly. Further, considering the exhaust gas environment in which the pressure sensor works, the glue is preferably a high-temperature resistant material, such as silica gel, and the material of the main body 11 is also selected from a high-temperature resistant material, such as polyphenylene sulfide (PPS) or polybutylene terephthalate (PBT) glass fiber reinforced material.

[0057] Furthermore, the body 11 has a first side 110 and a second side 120 disposed opposite to the first side 110, wherein the first side 110 is provided with a mounting flange 111 for fixing the pressure sensor on the vehicle, and the second side 120 is provided with a connection port 112 for electrical output, so as to facilitate connection with the outside, such as an ECU. Preferably, the bottom 130 of the body 11 is also provided with a positioning rod S, which can be seen in Figure 6 and Figure 7The first side 110 and the second side 120 are disposed on the bottom 130. The positioning rod S and the mounting flange 111 can be used in conjunction with each other to position and fix the pressure sensor on the vehicle.

[0058] The body 11 also has a third side 140 adjacent to the first side 110 and the second side 120. The third side 140 is also disposed on the bottom 130. Preferably, a first pipeline 113 and a second pipeline 114 are disposed on the third side 140. The first pipeline 113 is used to connect with a corresponding pipeline at the upstream of the engine particulate filter to introduce the gas at the upstream of the engine particulate filter into the housing 1. The second pipeline 114 is used to connect with a corresponding pipeline at the downstream of the engine particulate filter to introduce the gas at the downstream of the engine particulate filter into the housing 1. Further, different chambers are disposed inside the housing 1 to store the gas introduced by the aforementioned pipelines.

[0059] Figure 5 is a top view of the main body of the housing in the embodiment of the present invention, such as Figure 5 As shown, the main body 11 of the shell 1 is provided with an isolated first chamber 115 and a second chamber 116, wherein the first chamber 115 is connected to the first pipe 113 to introduce the gas upstream of the engine particulate filter into the first chamber 115, and the second chamber 116 is connected to the second pipe 114 to introduce the gas downstream of the engine particulate filter into the second chamber 116.

[0060] Figure 6 is a longitudinal cross-sectional view of the pressure sensor in the embodiment of the present invention when the cover plate is removed at a first viewing angle, such as Figure 6 As shown, the first sensing element 3 and the second sensing element 4 both have opposite front and back faces, and the front face of the first sensing element 3 is arranged in the first chamber 115, so that the pressure P1 of the gas in the first chamber 115 (i.e., the pressure at the upstream of the engine particulate trap) can be sensed, and the front face of the second sensing element 4 is arranged in the second chamber 116, so that the pressure P2 of the gas in the second chamber 116 (i.e., the pressure at the downstream of the engine particulate trap) can also be sensed. Preferably, the first chamber 115 and the second chamber 116 are arranged on the same side of the base 2 to simplify the structure and reduce the size.

[0061] In a preferred embodiment, a third chamber 117 is further provided in the housing 1, which is connected to and arranged opposite to the second chamber 116. For example, a channel can be reserved between the base 2 and the body 11 to connect the two. Furthermore, the back of the first sensing element 3 is arranged in the third chamber 117, so that the pressure P2 of the gas in the third chamber 117 can be sensed. In this way, the pressure P1 of the gas in the first chamber 115 is sensed by the front of the first sensing element 3, and the pressure P2 of the gas in the third chamber 117 is sensed by the back of the first sensing element 3. Finally, according to the two pressures, the pressure difference between the upstream and downstream of the engine particulate filter can be obtained. In this embodiment, the third chamber 117 can allow gas to flow into the back of the first sensing element 3 through a through hole. Here, through the connection of the chambers, the two sensing elements can simultaneously sense the pressure of the gas downstream of the engine particulate filter, which has a simple structure and is easy to measure, and can ensure that the condensed water can flow out smoothly and does not gather inside the sensor.

[0062] In addition, in this embodiment, the first sensing element 3 and the second sensing element 4 are preferably MEMS sensor elements, and more preferably the second sensing element 4 itself is provided with a vacuum chamber. Therefore, the second sensing element 4 can directly sense the vacuum degree (vacuum pressure) of its vacuum chamber, and thus can also directly sense the absolute pressure downstream of the engine particulate filter.

[0063] Figure 7 It is a longitudinal cross-sectional view of the pressure sensor in the embodiment of the present invention when the cover is set at a second viewing angle, and the second viewing angle is at a 90° angle to the first viewing angle. For example, the first viewing angle is the left end viewing angle of the pressure sensor, and the second viewing angle is the front end viewing angle of the pressure sensor. Figure 7 As shown, a fourth chamber 118 is further provided in the housing 1, which is provided on the same side of the base 2 as the third chamber 117 and is isolated from each other. In this embodiment, the third chamber 117 and the fourth chamber 118 can be defined by the body 11 and the cover plate 12, and the third chamber 117 and the fourth chamber 118 are isolated from each other by the cover plate 12. Thus, by installing the pressure signal processing device 5 in the fourth chamber 118, the isolation of the measured gas and the pressure signal processing device 5 can be achieved, so as to prevent the pressure signal processing device 5 from being corroded by the measured gas and affecting its use.

[0064] In this embodiment, the pressure signal processing device 5 includes a circuit board 51 and a digital application specific integrated circuit (AISC) 52 disposed on the circuit board 51, and also includes a number of passive components disposed on the circuit board 51, such as resistors, capacitors and other auxiliary components. The digital application specific integrated circuit 52 is used to simultaneously perform nonlinear and temperature drift compensation processing on the pressure difference information input by the first sensing element 3 and the absolute pressure information input by the second sensing element 4, and convert the processed two-way information into information suitable for output through one signal.

[0065] See also Figure 3 and Figure 4 , the first sensing element 3 and the second sensing element 4 both include a strain gauge and a Wheatstone bridge arranged on the strain gauge. The strain gauge is used to obtain the strain information generated by the gas pressure acting on it, and the Wheatstone bridge is used to convert the strain information into an electrical signal output, and then the digital application-specific integrated circuit 52 performs nonlinear and temperature drift compensation processing on the electrical signals output by the two Wheatstone bridges, and encodes the processed two-way electrical signals into a single-sided half-byte (SENT) digital communication protocol, through which the two-way electrical signals can be transmitted to the outside through a Pin needle, including but not limited to transmission to the ECU. In a preferred embodiment, the digital application-specific integrated circuit 52 can be an integration of multiple existing digital application-specific integrated circuit devices. Based on the disclosure of this application document, those skilled in the art should know how to implement the digital application-specific integrated circuit 52 to process two-way electrical signals into a signal suitable for one electrical output.

[0066] Furthermore, in order to transmit the electrical signal output by the sensing element to the digital application specific integrated circuit 52, the Wheatstone bridge needs to be connected to the circuit board 51. In a non-restrictive operation method: any sensing element is connected to multiple pins through multiple gold bonding wires (Au Bonding wires), and the multiple pins are connected to the circuit board 51. Among them, in order to prevent the gold bonding wires from being corroded by the measured gas, it is preferred to set a protective gel on the gold bonding wires. The gel is preferably fluorinated silicone. On the one hand, the fluorinated silicone is soft and will not affect the normal transmission of pressure. On the other hand, the fluorinated silicone has good dielectric resistance and can protect the sensing element from working normally and stably in the exhaust gas environment.

[0067] Furthermore, any sensing element has four output leads, each of which is connected to a pin through a gold binding wire. Therefore, the pressure signal processing device 5 of this embodiment needs to be connected to two sensing elements through eight pins. During actual assembly, the eight pins are fixed on the base 2, and one end of each pin passes through the base 2 and is connected to the lead of the sensing element through a gold binding wire, and the other end also passes through the base 2 and is further inserted into a via on the circuit board 51. The connection method between these pins and the circuit board 51 can be manual soldering, automatic soldering, or laser soldering.

[0068] Further, if Figure 3 and Figure 4 As shown, the base 2 is also provided with three other pins. Specifically, eight pins form a group and are arranged on one side of the base 2, and three pins form another group and are arranged on the other side of the base 2. One end of the three pins is connected to the circuit board 51, and the connection method can also be manual soldering, automatic soldering or laser soldering. In practice, the three pins are used to form an electrical output port with the aforementioned connection port 112. Specifically, the connection port 112 includes a cover and three pins arranged in the cover, and each pin is also provided with a flat insert, which can be connected to the pin by welding. In addition, both the pin and the flat insert can be made of copper-tin alloy material, and the surface is preferably gold-plated to avoid corrosion by the measured medium. Then, in actual application, through the single-sided half-byte (SENT) digital communication protocol, two signals can be output to the outside through one of the pins, while the other pin is used for grounding, and the remaining pin is used for power supply of the circuit board.

[0069] Furthermore, the material of the base 2 is preferably selected from epoxy resin modified materials and can be injection molded. Since epoxy resin modified materials not only have a low thermal expansion coefficient, but also have good medium resistance, it can ensure that the pressure measurement unit can work stably for a long time under harsh conditions such as engine exhaust. In particular, the thermal expansion coefficient of this material is close to that of the silicon-based MEMS sensor element, which can ensure that the MEMS sensor element is connected with less thermal stress. Therefore, in this embodiment, the first sensing element 3 and the second sensing element 4 are preferably MEMS sensor elements, which are small in size and can save space, and preferably, corresponding grooves are provided on the base 2 to accommodate the first sensing element 3 and the second sensing element 4, and the sensing elements can be fixed to the base 2 by glue, and the protective gel can be prevented from being lost through the grooves.

[0070] Furthermore, the assembly process of the pressure sensor of this embodiment preferably includes the following steps:

[0071] First, glue is dispensed inside the body 11, for example, in a glue tank; the glue is preferably the same as the glue used in the pressure measurement unit;

[0072] Then, the pressure measuring unit is installed into the body 11; in order to achieve a good sealing connection between the pressure measuring unit and the housing 1, the periphery of the base 2 is preferably provided with edges, which can enhance the glue bonding strength between the pressure measuring unit and the housing 1;

[0073] Afterwards, the three pins can be welded together with the three flat inserts fixed on the body 11 by resistance welding;

[0074] Then, glue dispensing can be continued and the cover plate 12 can be installed;

[0075] Next, the glue is cured at high temperature to fix the pressure measuring unit to the body 11 and the cover plate 12;

[0076] Finally, air tightness and functionality tests are carried out.

[0077] Therefore, by obtaining the pressure sensor of this embodiment, the following benefits can be obtained:

[0078] First, the pressure sensor only needs two sensing elements and a small amount of connecting pipes to measure the upstream and downstream pressure difference and the downstream absolute pressure of the engine particulate filter, and the signals output by the two sensing elements can be processed into signals suitable for one electrical output through a digital application-specific integrated circuit, and then the one electrical output can be transmitted to the outside. Therefore, the one electrical output only occupies one external interface, and the system cost is low;

[0079] Second, the pressure sensor directly measures the desired pressure difference between the upstream and downstream of the engine particulate filter through the first sensing element. Therefore, no additional calculation is required externally, the measurement error is small, the measurement accuracy is high, and the regeneration of the engine particulate filter can be controlled more accurately.

[0080] Third, the pressure sensor sets two sensing elements and a digital application-specific integrated circuit on the same base, which can realize calibration and testing at the module level, making early development and testing convenient;

[0081] Fourth, the pressure sensor forms various isolated chambers and gas introduction pipelines through the shell structure, thereby ensuring that condensed water can flow out smoothly and does not accumulate inside the sensor, ensuring that the pressure sensor can be used stably for a long time;

[0082] Fifth, the assembly process of the pressure sensor is simpler, the production efficiency is improved, and the production cost is lower.

[0083] Finally, it should be noted that the preferred embodiments of the present invention are as described above, but are not limited to the scope disclosed in the above embodiments. For example, the layout of each chamber in the shell is not particularly limited. In addition, the two pipelines can be self-contained or provided externally. In addition, the pressure signal processing device 5 can adopt existing PLC and other control devices. Based on the contents disclosed in this application, those skilled in the art should know how to realize the communication connection between the control device and the sensing element and the outside.

[0084] Obviously, those skilled in the art can make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A pressure sensor for a vehicle, characterized in that: It comprises a shell and a base arranged in the shell, a first sensing element, a second sensing element and a pressure signal processing device, wherein the first sensing element, the second sensing element and the pressure signal processing device are all arranged on the base, and the pressure signal processing device is connected to the first sensing element and the second sensing element respectively; The housing is provided with a first chamber and a second chamber isolated from each other, and is further provided with a third chamber connected to the second chamber; the first chamber and the third chamber are arranged opposite to each other and are arranged on the same side of the base as the second chamber; the first sensing element and the second sensing element each have two opposite surfaces; one surface of the first sensing element is in the first chamber, and the other surface is in the third chamber; one surface of the second sensing element is in the second chamber, and the other surface is in a vacuum environment; Among them, the first sensing element is used to sense the pressure difference of the gas between the upstream and downstream of the engine particulate filter, and feed back the pressure difference information of the gas to the pressure signal processing device; the second sensing element is used to sense the absolute pressure of the gas downstream of the engine particulate filter, and feed back the absolute pressure information to the pressure signal processing device; the pressure signal processing device is used to process the received pressure difference information and absolute pressure information of the gas so that the pressure difference information and the absolute pressure information can be output through one signal, wherein the pressure signal processing device includes a circuit board and a digital application specific integrated circuit arranged on the circuit board; the digital application specific integrated circuit is used to simultaneously perform nonlinear and temperature drift compensation processing on the pressure difference information input by the first sensing element and the absolute pressure information input by the second sensing element, and encode the processed pressure difference information and absolute pressure information so that the pressure difference information and the absolute pressure information can be output through one signal using a single-sided half-byte digital communication protocol.

2. The pressure sensor for a vehicle according to claim 1, characterized in that: The shell further includes a fourth chamber isolated from the other chambers, and the pressure signal processing device is disposed in the fourth chamber.

3. The pressure sensor for a vehicle according to claim 2, characterized in that: The third chamber and the fourth chamber are arranged on the other side of the base.

4. The pressure sensor for a vehicle according to claim 1, characterized in that: A first pipeline and a second pipeline are provided on one side of the housing. The first pipeline is used to introduce gas upstream of the engine particulate trap, and the second pipeline is used to introduce gas downstream of the engine particulate trap.

5. The pressure sensor for a vehicle according to claim 1, characterized in that: The housing has a first side and a second side that are oppositely disposed, the first side is provided with a mounting flange for fixing the pressure sensor on a vehicle, and the second side is provided with a connection port for connecting with an external mechanism.

6. The pressure sensor for a vehicle according to claim 5, characterized in that: The first side and the second side are arranged on the bottom of the housing, and a positioning rod for positioning the pressure sensor on the vehicle is arranged on the bottom.

7. The pressure sensor for a vehicle according to claim 1, characterized in that: The shell comprises a main body and a cover plate arranged at an opening of the main body.

8. The pressure sensor for a vehicle according to claim 7, characterized in that: The base is connected to the body and the cover plate through silicone sealing.

9. The pressure sensor for a vehicle according to claim 1, characterized in that: The first sensing element and the second sensing element both include a strain gauge and a Wheatstone bridge arranged on the strain gauge; wherein the first sensing element and the second sensing element are respectively connected to four pins through gold binding wires, and the four pins are connected to the pressure signal processing device.

10. The pressure sensor for a vehicle according to claim 9, characterized in that: The gold binding wire is provided with a protective gel, and the protective gel is a fluorine-containing gel.

11. The pressure sensor according to claim 9, characterized in that: The first sensing element and the second sensing element are both MEMS sensing elements.

12. The pressure sensor for a vehicle according to claim 1, characterized in that: The pressure signal processing device is connected to the outside via three pins, one of which is used to transmit the signal.

13. The pressure sensor for a vehicle according to claim 9 or 12, characterized in that: The surface of the pin is gold-plated.

14. The pressure sensor for a vehicle according to claim 1, characterized in that: The base is made of epoxy resin modified material.

15. A pressure measurement method for a vehicle, characterized in that: include: A shell and a base, a first sensing element, a second sensing element and a pressure signal processing device arranged in the shell are provided, wherein the first sensing element, the second sensing element and the pressure signal processing device are all arranged on the base, and the pressure signal processing device is connected to the first sensing element and the second sensing element respectively; a first chamber and a second chamber isolated from each other are arranged in the shell, and a third chamber communicating with the second chamber is also arranged; the first chamber and the third chamber are arranged opposite to each other and are arranged on the same side of the base as the second chamber; the pressure signal processing device includes a circuit board and a digital application specific integrated circuit arranged on the circuit board; The pressure measurement method further comprises: Sensing the pressure difference of the gas between the upstream and downstream of the engine particulate filter by the first sensing element includes: The first sensing element senses the pressure of the gas in the first chamber through one surface, and senses the pressure of the gas in the third chamber through another surface, and obtains the pressure difference between the upstream and downstream of the engine particulate trap according to the pressure of the gas in the first chamber and the pressure of the gas in the third chamber; and then feeds back the pressure difference information of the gas to the pressure signal processing device; Sensing the absolute pressure of the gas downstream of the engine particulate trap by the second sensing element comprises: The second sensing element senses the pressure of the gas in the second chamber through one surface, and senses the vacuum degree of a vacuum environment through another surface, and obtains the absolute pressure downstream of the engine particulate trap according to the pressure of the gas in the second chamber and the vacuum degree; and then feeds back the absolute pressure information to the pressure signal processing device; and The pressure signal processing device processes the received pressure difference information and absolute pressure information of the gas so that the pressure difference information and the absolute pressure information can be output through one signal, and the operation steps include: The digital application specific integrated circuit simultaneously performs nonlinear and temperature drift compensation processing on the pressure difference information input by the first sensing element and the absolute pressure information input by the second sensing element, and encodes the processed pressure difference information and absolute pressure information so that the pressure difference information and the absolute pressure information can realize one signal output using a single-sided half-byte digital communication protocol.

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