JP6208251B2 - Physical quantity measuring device - Google Patents

Description

  The present invention relates to a physical quantity measuring apparatus including a humidity sensor inserted into an intake pipe connected to a combustion chamber of an internal combustion engine of an automobile.

  In the automobile field, fuel efficiency, CO2, and exhaust gas (mainly nitrogen oxides (NOx) and particulate matter (PM)) regulations are becoming stricter year by year, and a new control method for achieving the regulations in future internal combustion engine control Many have been studied. Among them, there are a wide variety of physical quantity measuring devices used for various controls. In particular, since physical quantities such as air, temperature, humidity, and pressure in an intake pipe connected to a combustion chamber of an internal combustion engine directly affect fuel consumption and exhaust gas, accurate measurement is required.

  Fuel consumption, CO2, and exhaust gas regulations are calculated and defined based on a driving cycle represented by European NEDC. In future regulations, not only specified values but also driving cycle conditions and on-board diagnostic system (OBD) regulated values will be changed.

  Currently, measurement of mass flow, pressure, and temperature is generally used as a physical quantity measurement device inserted into the intake pipe. Against this background, absolute humidity (the amount of moisture in the air) is controlled by internal combustion engine control. The control used is attracting attention.

  Since moisture in the air affects the flame propagation time in the combustion control of the internal combustion engine, for example, in a gasoline engine, the combustion efficiency deteriorates. Or, in a diesel engine, an influence such as an increase in PM emission amount with a decrease in combustion temperature is known.

  Here, the absolute humidity indicates the amount of water (g gram / kg kilogram) contained in the air, and can be calculated from the temperature, relative humidity, and pressure in the air. On the other hand, the relative humidity indicates the ratio (% percent) of the amount of moisture in the air.

  As described above, temperature and pressure sensors have been used in the automobile field for a long time, but are not well known as relative humidity sensors in the air flowing through the intake pipe.

Currently, in the automobile field, a humidity sensor integrated with an air flow rate measuring device is known as a known technique. (See Patent Documents 1 to 3.)
The air flow rate measuring devices of Patent Documents 1 and 2 include a sub-passage that takes in air flowing through a main air passage (also simply referred to as an intake pipe), and further includes a second sub-passage that takes in air flowing through the sub-passage. If there is no auxiliary passage, a heating resistor that measures the air flow rate is arranged to detect the mass flow rate. Further, the relative humidity of air is detected by a humidity sensor arranged in the second sub-passage.

JP 2010-43883 A JP 2012-163505 A JP 2013-36892 A

  In recent years, in the automobile field, various technical improvements have been made to improve exhaust gas regulations, safety, comfort, convenience, etc. in addition to vehicle basic performance. In such technical improvements, a wide variety of sensors are used. Therefore, the number of wire harnesses connecting the sensor and the engine control unit (hereinafter referred to as ECU) is increased and complicated, and there are problems in terms of cost and space in the engine room.

  For this reason, nowadays, there is an increasing need for a physical quantity measuring device in which a plurality of sensors and control devices are integrated. At present, an air flow rate measuring device in which a temperature and a flow rate sensor used for measuring a physical quantity in an intake pipe are integrated is generally used. Furthermore, there is an air flow rate measuring device in which a humidity sensor and a pressure sensor described in Patent Documents 1 to 3 are integrated.

  In the sensor used in the intake pipe connected to the combustion chamber of the internal combustion engine, such as the air flow rate measuring device, the adhesion of dust, dust (hereinafter referred to as a pollutant) or water droplets is prevented, and the physical quantity is changed to a transient change. Integration is required in consideration of tracking (also simply referred to as response performance).

  When the air in the atmosphere is taken into the most upstream part of the intake pipe (the most downstream part is the combustion chamber side), there is an air cleaner equipped with a filter element to remove the intrusion of contaminants or rainwater contained in the air. Be placed. However, the ability to remove dirt and water droplets by the filter element is not perfect, and a certain amount enters the intake pipe. The sensor usually exposes a sensor for detecting a physical quantity to the air and measures the physical quantity. Therefore, permanent performance deterioration or temporary output abnormality occurs due to the contamination or water droplets adhering to the detection element. In particular, since sensors used in automobiles are required to operate for several decades, a preventive measure is essential.

  Further, the air in the intake pipe changes transiently due to acceleration / deceleration during traveling of the automobile. Therefore, the sensor used for measuring the physical quantity in the intake pipe needs to follow the transient change. For example, an air flow rate measuring device used in a gasoline engine measures a mass flow rate of air taken into a combustion chamber, and a fuel injection amount is determined based on the mass flow rate. For this reason, if a response delay of the sensor output occurs during a transient change in air, an error occurs in mass flow measurement, leading to deterioration in fuel consumption.

  An air flow rate measuring device generally used in the automobile field includes a sub-passage that bypasses the main air passage in order to take the environmental conditions into consideration. A flow rate sensor is disposed in the sub-passage, and has a structure that suppresses contamination and water droplets from adhering to the flow rate sensor. For example, as described in Patent Documents 1 and 2, the second sub-passage is provided in the sub-passage.

  Further, in order to follow a transient change in the air in the intake pipe, the casing length is set so that the sub-passage inlet can be arranged near the center of the intake pipe. In an ideal air flow, the center of the intake pipe has the fastest flow rate and becomes a stable flow, so that it is easy to follow a transient change. On the other hand, in the vicinity of the wall surface, wall resistance is generated and the flow velocity becomes slowest.

  In other words, when integrating a plurality of sensors into a single physical quantity measuring device, it is important to first consider the environmental conditions and maintain the individual sensor performance. Secondly, it is necessary to realize an optimal mounting position for maintaining the sensor performance with a single housing.

  Here, in the air flow rate measuring device in which the humidity sensors of Patent Documents 1 and 2 are integrated, the flow rate sensor is disposed in the sub-passage that bypasses the main air passage, and further, the humidity sensor is located in the second sub-passage that bypasses the sub-passage. Is arranged. In this case, the response performance of the humidity sensor arranged in the second sub-passage depends on the flow velocity taken into the sub-passage. In addition, since the air reaching the humidity sensor is subjected to the wall resistance of the sub-passage and the second sub-passage and the flow velocity is reduced, there remains room for improvement.

  On the other hand, the air flow rate measuring device of Patent Document 3 is provided with a humidity sensor exposed from the outer wall of the housing to the main air passage. The humidity sensor is resin-molded and integrated with the casing when the casing of the air flow rate measuring device is resin-molded. In this case, the humidity sensor is directly exposed to dirt and water droplets flying with the air in the intake pipe. When soiled substances adhere to the humidity sensor, there is a risk that a long-term characteristic shift will occur. On the other hand, when a water droplet adheres, the dew condensation state occurs, the humidity sensor becomes saturated, and a desired value may not be obtained for a certain period of time as humidity detection.

  An object of the present invention is to provide a physical quantity measuring device that maintains environmental resistance while maintaining responsiveness even if a plurality of physical quantity sensors are integrated.

  In the present invention, in order to solve the above problems when integrating the humidity sensor, for example, the configuration described in the claims is adopted.

  Specifically, a flange that is supported and fixed to the intake pipe, a housing part that is integrally formed with the flange and resin and inserted into the intake pipe, and a housing and a cover that constitute the housing part, In a physical quantity measuring device including at least one sensor connected to a combustion chamber of an internal combustion engine and measuring a physical quantity of air flowing through a main air passage inside an intake pipe, the main air passage is provided in the casing portion or the flange portion. An introduction hole connected to at least one sub-passage or main air passage for bypassing the air, and a second sub-passage that is structurally separated from the sub-passage or introduction hole in the housing portion, A sensor for detecting a physical quantity of air is provided in the sub-passage or the introduction hole, and a humidity sensor for measuring the humidity of the air is provided in the second sub-passage.

  ADVANTAGE OF THE INVENTION According to this invention, even if it integrates several physical quantity sensors, it becomes possible to provide the physical quantity measuring device which maintained environmental resistance performance, maintaining responsiveness.

It is the figure which showed Example 1 of the physical quantity measuring apparatus provided with the humidity sensor. It is an example which shows the physical quantity measuring device internal structure provided with the humidity sensor. FIG. 3 is a front view of the physical quantity measuring device in FIG. 2. It is the figure which showed the circuit package in FIG. It is the figure which showed the 2nd sub channel | path internal structure (cross section) in FIG. It is the side view (cross section) which showed Example 2 of the physical quantity apparatus provided with the humidity sensor. It is a front view (sectional drawing) of the physical quantity measuring device in FIG. It is the side view (sectional view) which showed Example 3 of the physical quantity apparatus provided with the humidity sensor.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

  In this embodiment, an air flow rate measuring device will be described as an example of the physical quantity measuring device.

  1 to 5 show an example of the configuration of an air flow rate measuring device provided with a humidity sensor. An air flow rate measuring device used in an internal combustion engine is usually arranged at a downstream portion of an air cleaner. And it inserts in the intake pipe or exclusive duct 106 connected with an air cleaner.

  Here, the air cleaner has a filter element for filtering dust, dust and the like in the air, and is installed at the most upstream portion of the intake pipe connected to the internal combustion engine in order to take clean air into the intake pipe. In the air flow rate measuring apparatus, a casing portion including a circuit package (or circuit board) 400 or the like is inserted into an opening of an intake pipe or a dedicated duct 106, and a flange portion 101 that is resin-molded together with the casing portion is a screw (in the drawing, (Not shown). Further, by providing the sealing material 104 formed of a rubber material, leakage of fluid from the intake pipe duct or the dedicated duct 106 and entry of dust, dust and the like from the external environment are prevented.

  The air flow rate measuring device includes a housing constituted by a housing 102 and covers 103a and 103b, a sub-passage 300 constituted by an inner wall shape of the housing 102 and covers 103a and 103b, and a sub-passage 300 independent of the sub-passage 300. Two sub-passages 200, a circuit package 400 disposed in the housing, a flow rate sensor 401 for measuring the air flow rate in the sub-passage 300, and a humidity sensor for measuring the humidity of air in the second sub-passage 200. 402.

  A housing 102 formed of a resin material includes a connector terminal 105 formed of a metal member and a shape of a connector 100 that is mechanically connected to a connector on the ECU side. The connector terminal 105 is insert-molded at the time of resin molding of the housing 102, and the connector terminal 105 is welded and electrically connected to the lead frame 403 of the circuit package 400. On the other hand, the tip of the connector terminal 105 is electrically connected to the vehicle ECU via a harness.

  Covers 103a and 104b formed of a resin material are provided on the outer periphery of the housing 102 to protect the circuit package 400, the humidity sensor 402, the flow sensor 401, the lead frame 403, the connector terminal 105, and the like disposed in the housing 102. It is fitted into the groove shape and fixed by adhesion.

  The circuit package 400 includes a ceramic substrate or a printed circuit board on which electronic components are mounted with solder or the like. In this example, an electronic component is mounted on a lead frame 403 known as a semiconductor package and sealed with an epoxy resin. Point.

  The sub-passage 300 and the second sub-passage 200 formed by the housing 102 and the covers 103a and 103b bypass the air flowing through the main air passage 301 (hereinafter referred to as main air), and fouling substances or water droplets flying along with the main air. Has a role of suppressing direct adhesion to the flow sensor 401 and the humidity sensor 402. At the same time, the air bypassed into the sub-passage 300 has a rectifying effect, and has the effect of suppressing the turbulence of the air, enabling stable physical quantity measurement. Furthermore, the sub-passage 300 and the second sub-passage 200 are formed independently of each other, and each has a structure for directly taking in the main air.

  Thereby, since the flow sensor 401 and the humidity sensor 402 can be independently arranged in the sub passage 300 and the second sub passage 200, respectively, a passage structure suitable for each sensor can be obtained. The performance can be easily secured and integrated without affecting the performance of the sensor.

In general, the flow rate and humidity, which are physical quantities in the air, have different transition times (hereinafter referred to as response time constants). The response time constant of air flow is several milliseconds, whereas the response time constant of humidity is several seconds. Humidity changes depend on temperature and pressure changes, but are mainly due to temperature response time constants. The ideal main air flow in the intake pipe has a distribution in which the flow velocity decreases as the velocity near the center is the fastest and approaches the wall surface. Therefore, the auxiliary passage 300 in which the flow sensor 400 is disposed is arranged near the center 10 of the main air passage where the flow velocity distribution in the main air passage 301 is the fastest, thereby following the transient change of the main air. It becomes easy to do. On the other hand, the second sub-passage 200 in which the humidity sensor 402 with a slow response time constant is arranged is a housing portion of the air amount measuring device between the main air passage center 10 and the flange 101, which is a relatively slow flow rate. Can be formed.
Furthermore, environmental resistance performance can be maintained by adopting a sub-passage structure that suppresses fouling substances or water droplets flying in the main air passage.

  Details of the second sub-passage will be described with reference to FIGS.

  The second sub-passage 200 in which the humidity sensor 402 is disposed has an inlet 201 and an outlet 202 for bypassing the main air. The inlet 201 is formed in a part of the housing 102 and is upstream of the main air passage 300. Be placed. On the other hand, the outlet 202 is formed in the cover 103 a serving as a side wall of the air flow measuring device, and is disposed on the downstream side of the main air passage 300. In addition, the inlet 201 opens in a direction perpendicular to the main air flow 11.

  Thereby, the main air can be taken into the second sub-passage 200 by the dynamic pressure generated by the air flow, and the responsiveness can be improved.

  Furthermore, the inlet 201 is provided with an inclined portion 203 formed by the housing 102, the outlet 202 is disposed at a position that is vertically offset from the inlet 201 with respect to the main air flow 11, and at least one second sub-passage 200 is provided. It has a bent part.

  As a result, the contaminants and water droplets flying in the main air passage 11 collide with the wall surface of the inlet 201 and thus can be prevented from directly entering the second sub-passage 200, and the environmental resistance performance of the humidity sensor 402 can be reduced. Can be improved.

  On the other hand, the opening area of the outlet 202 is set larger than the opening area of the inlet 201. As a result, the pressure difference between the inlet and the outlet changes depending on the opening area of the outlet 202, and the response performance of the humidity sensor 402 can be adjusted. Furthermore, since the cover 103a has a simpler structural shape than the housing 102, it is possible to suppress as much as possible the cost impact associated with the structural change.

  In Example 1, the example of the air flow measuring device was shown as a physical quantity measuring device provided with the humidity sensor. In the second embodiment, an example in which a humidity sensor is integrated with a pressure measuring device that measures the pressure in an intake pipe as a physical quantity measuring device will be described.

  FIG. 6 is a configuration example of a pressure measuring apparatus having the second sub passage 200 in which the humidity sensor 402 having the same shape shown in the first embodiment is disposed.

  Among the pressure measuring devices provided with the humidity sensors of FIGS. 6 to 7, the description will be made with respect to the components having the same functions and the same reference numerals shown in FIGS. Omitted.

  The pressure measuring apparatus according to the second embodiment includes a flange 101 that is inserted into and supported by an intake pipe or a dedicated duct 106, and a circuit board 500 on which electronic components are mounted on the flange 101 is disposed in a circuit chamber 503. 502 is mounted on the back surface of the circuit board 500. The circuit board 500 and the connector terminal 105 are connected by an aluminum wire 501 and can be electrically connected to the ECU. As shown in FIG. 7, the pressure sensor 502 is arranged inside the introduction hole 504 connected to the main air passage 301 formed in the flange 102 portion, and enables pressure measurement inside the main air passage 301. The introduction hole 504 has one opening, and the opening is located on the inner wall of the intake pipe into which the housing is inserted. The pressure sensor 502 is preferably provided with an introduction hole at a position that does not change the flow velocity as much as possible in order to measure the static pressure in the main air passage (here, the static pressure is the pressure at which the air works in a stationary state). Therefore, by adopting the configuration of the present embodiment, stable static pressure measurement is possible without being affected by the main air flow. At the same time, the configuration is such that dirt and water droplets flying along with the main air are difficult to enter the sub-passage.

  As in the first embodiment, the introduction hole 504 is formed independently of the second sub-passage 200, and is disposed at a location that considers the performance (responsiveness and measurement stability) and environmental resistance performance of the pressure sensor 502 and the humidity sensor 402, respectively. Is done. Thereby, it becomes easy to secure and integrate the performance of each sensor.

  In the first or second embodiment, an example of a physical quantity measuring device in which at least one physical quantity sensor such as the flow sensor 401 or the pressure sensor 502 and the humidity sensor 402 are integrated is shown.

  In the third embodiment, an example of a physical quantity measuring apparatus in which a flow sensor 401, a pressure sensor 502, and a humidity sensor 402 are integrated is shown in FIG.

  FIG. 8 shows the second sub-passage 200 in which the humidity sensor 402 having the same shape shown in the first and second embodiments is arranged, the sub-passage 300 in which the flow sensor 401 is arranged, and the introduction hole in which the pressure sensor 502 is arranged. 504 is a configuration example of a physical quantity measuring apparatus in which 504 is formed independently and takes in or connects the air in the main air passage 301 and integrates three types of sensors.

  Among the physical quantity measuring devices provided with the humidity sensor 402, the flow sensor 401, and the pressure sensor 502 in FIG. 8, the same reference numerals as those shown in FIGS. The description of the portion is omitted.

  As described so far, the sensor performance can be secured and integrated easily by making the sub-paths in which the respective physical quantity sensors are arranged independent of each other. By integrating a plurality of physical quantity sensors, it will become a physical quantity measuring apparatus with high needs in the future as described above, such as the number of parts and cost reduction.

10 Main air passage center 11 Main air passage flow direction 100 Connector 101 Flange 102 Housing 103a Cover 103b Cover 104 Sealing material 105 Connector terminal 106 Intake pipe (or dedicated duct)
200 second sub-passage 201 second sub-passage inlet 202 second sub-passage outlet 203 second sub-passage inclined portion 300 sub-passage 301 main air passage 400 circuit package 401 flow sensor 402 humidity sensor 403 lead frame 500 circuit board 501 aluminum wire 502 Pressure sensor 503 Circuit chamber 504 Introduction hole

Claims (4)

A combustion chamber of an internal combustion engine, comprising: a flange supported and fixed to the intake pipe; a housing part integrally formed with the flange and resin; and a housing and a cover constituting the housing part. In the physical quantity measuring device provided with at least one sensor that measures the physical quantity of the air that is connected to the main air passage inside the intake pipe,
An introduction hole connected to at least one sub-passage or main air passage provided in the housing part or the flange part to bypass the air in the main air passage;
A second sub-passage that is structurally separated from the sub-passage or the introduction hole in the housing portion;
A sensor for detecting a physical quantity of air in the auxiliary passage or in the introduction hole;
The second sub-passage is provided between the flange and the main air passage center,
A humidity sensor for measuring the humidity of air inside the second sub-passage ;
The inlet of the second sub-passage opens in a direction perpendicular to the air flow in the main air passage;
The outlet of the second sub passage opens parallel to the main air flow direction, is formed on a cover side wall on the downstream side of the air flow in the main air passage, and the air flow in the main air passage is The physical quantity measuring device is arranged at a position offset in a vertical direction from the entrance . The physical quantity measuring device according to claim 1 ,
Entrance mouth of the second sub passage is arranged in the main air flow upstream section, and has an inclined portion,
The physical quantity measuring device according to claim 1, wherein the inclined portion is formed in a housing portion including the housing and the cover. The physical quantity measuring device according to claim 1 ,
The physical quantity measuring device, wherein the second sub-passage has at least one bent portion. The physical quantity measuring device according to claim 1 ,
Area of the opening of the output port, the physical quantity measuring device being larger than the opening area of the opening of the inlet mouth.

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