JP2018077070A - Pressure measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure measurement device capable of suppressing the progress of compression set at high temperatures while maintaining the sealability at low temperature of an O ring and usable in a high-temperature environment.SOLUTION: The pressure measurement device of the present invention includes a first O ring for low temperature compatibility and a second O ring for high temperature compatibility, and the second O ring is disposed closer to the inside of the intake pipe than the first O ring.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pressure measuring device that is mounted on an intake / exhaust system of an internal combustion engine and detects the pressure of intake / exhaust.

  The pressure measurement device is mounted, for example, in an intake passage of an automobile engine, measures the pressure of intake air, and is used for control of the fuel injection amount and optimization of operating conditions. An automobile engine or the like is required to measure with high accuracy in order to reduce fuel consumption.

  In the pressure measuring device for measuring the pressure as described above, only the pressure introducing port is inserted into a hole formed in the intake pipe or the like of the engine, and the module main body is disposed outside the intake pipe.

  The intake pipe changes in the range of 10 kPa to 400 kPa with respect to the atmospheric pressure of 100 kPa. For this reason, a sealing material is required to keep airtight between the hole opened in the intake pipe and the pressure inlet.

  As a prior art document of such a pressure measuring device, Patent Document 1 (Japanese Patent Application No. 2007-168361) has a configuration in which an O-ring is disposed as a sealing material around a pressure inlet.

  Until now, the environmental temperature in the automobile engine room is in the range of −40 ° C. to 130 ° C., and the O-ring of the pressure measuring device can be used in the range of −40 ° C. to 150 ° C.

Japanese Patent Application No. 2007-168361

  In recent automobile engines, a small engine equipped with a supercharger has become widespread. In these engines, the temperature in the engine room is in the range of −40 ° C. to 130 ° C. as before, but the intake air temperature measured by the pressure measuring device is getting higher.

  In the intake system from the outside air inlet of the automobile engine to the intake valve, there are devices such as an air cleaner, a supercharger, an intercooler, and a throttle valve that generate a pressure difference before and after that. Different. In terms of temperature, the temperature in the section between the supercharger and the intercooler is the highest and may exceed 170 ° C.

  In recent years, there has been a demand for pressure measurement in every section of the intake system for the purpose of more precise engine control, and pressure measurement in the section between the turbocharger with a high intake temperature and the intercooler is also included in the request. .

  Due to the increase in the usage environment of such a pressure measuring device, the compression set of a conventional O-ring progresses quickly, and the O-ring sealability cannot be ensured for the lifetime of the product.

  Therefore, it is conceivable to change the composition of the O-ring material so that the progression of compression set at high temperatures is reduced. However, when the composition is changed in this way, there arises a problem that the sealing performance at a low temperature is deteriorated.

  There are also rubber materials that have both compression set suppression at high temperatures and sealing properties at low temperatures, but they are special materials that are very expensive and are vulnerable to fuels such as gasoline and organic solvents. Have disadvantages in different ways.

  The present invention solves the above-mentioned problems, and its object is to reduce the progress of compression set at high temperatures while maintaining the sealability of the O-ring at low temperatures, and to be used in an environment where the ultimate temperature is high. Is to provide.

  In order to solve the above-mentioned problems, the pressure measuring device of the present invention includes a first O-ring for low temperature and a second O-ring for high temperature, and the second O-ring is a first O-ring. It is configured to be arranged closer to the inside of the intake pipe.

  As a result, when the intake air temperature is high, the second O-ring is hermetically sealed, so that the first O-ring can be protected from high-temperature gas. At low temperatures, the first O-ring is insufficient even if the second O-ring is insufficiently sealed. Since the airtightness can be maintained by the O-ring, it is possible to provide a pressure measuring device that can be used even in a measurement environment where the intake air temperature is high.

  According to the present invention, without using an expensive and special O-ring, the sealing characteristic between the hole opened in the intake pipe and the pressure inlet in the temperature range from −40 ° C. to a high temperature of 170 ° C. or more is long. Since the period can be secured, a pressure measuring device that can be used in an environment where the intake air temperature is −40 ° C. to 170 ° C. or higher is obtained.

1 is a configuration diagram of a pressure measuring device according to Embodiment 1 of the present invention. Configuration diagram of a pressure measuring device according to an embodiment of the prior art Mounting diagram of pressure measuring device according to an embodiment of the prior art Mounting diagram of pressure measuring apparatus according to Embodiment 1 of the present invention Configuration diagram of pressure measuring apparatus according to embodiment 2 of the present invention Configuration diagram of pressure measuring apparatus according to Embodiment 3 of the present invention Mounting diagram of pressure measuring device according to embodiment 3 of the present invention Mounting diagram of pressure measuring device according to embodiment 4 of the present invention

  The pressure measuring device is mounted, for example, in an intake passage of an automobile engine, and is used for measuring intake pressure.

  In the pressure measuring apparatus as described above, only the pressure introducing port is inserted into a hole formed in the intake passage of the engine, and the module main body is disposed outside the intake pipe. FIG. 3 is a sectional view showing the arrangement of a pressure measuring device according to a conventional embodiment. In FIG. 3, the outside of the intake passage is the environment in the automobile engine room, and the temperature is in the range of −40 ° C. to 130 ° C. The inside of the intake passage is an environment in the intake passage, and is connected to the pressure measurement element module by the pressure introduction port 5 of the pressure measurement device 1. The conventional pressure measuring device 1 is used in a place where the temperature in the intake passage is in the range of -40 ° C to 130 ° C.

  The pressure in the intake passage varies in the range of 10 kPa to 400 kPa. Since the atmospheric pressure is about 100 kPa, a sealing material is required to keep airtight between the hole opened in the intake passage and the pressure introduction port 5. As shown in FIGS. 2 and 3, the conventional pressure measuring device has a configuration in which one O-ring is disposed around the pressure inlet as a sealing material. In a conventional use environment, an O-ring of a pressure measuring device that can be used in a range of −40 ° C. to 130 ° C. is used.

  Further, since it is used in an engine room of an automobile, it is required not to be deteriorated by a fuel such as gasoline, an organic solvent, a lubricating oil, a chemical or the like. For this reason, fluorine rubber (FKM), nitrile rubber (NBR), and hydrogenated nitrile rubber (HNBR) are mainly used as materials for O-rings in automotive pressure measuring devices.

  However, in recent years, there is a demand for pressure measurement in a section where the intake air temperature is 170 ° C. or higher, such as between a supercharger and an intercooler.

  Therefore, an O-ring used for the pressure measuring device 1 is required to be usable in an intake air temperature range of 170 ° C. or higher.

  The important characteristics in the operating temperature range of the O-ring are that the compression set at a high temperature is small and the sealability can be secured at a low temperature.

  There are no materials that can be used in the temperature range of -40 ° C to 170 ° C from the FKM material lineup, NBR material lineup, and HNBR material lineup. This is because a material having a small compression set at a high temperature cannot secure a sealing property at a low temperature, and a material capable of ensuring a sealing property at a low temperature has a large compression set at a high temperature.

  In view of the above, embodiments of the present invention will be described in detail below with reference to the drawings.

  As shown in FIG. 1, the first O-ring 2 and the second O-ring 1 which are made of different materials are provided, and the sealability can be ensured in the intake air temperature range of −40 ° C. to 170 ° C. for the product life. . In this configuration, the first O-ring 2 is an O-ring having excellent sealing performance at a low temperature, and the second O-ring 3 is an O-ring having a low compression set at a high temperature.

  FIG. 4 shows a sectional view of an embodiment in which the pressure measuring device of the present invention is arranged in the intake passage 10.

  For example, when the operating temperature environment of the pressure measuring device is an intake air temperature range of −40 ° C. to 170 ° C. and the temperature range in the engine room outside the intake passage is −40 ° C. to 130 ° C., FIG. The temperature range of the inner wall surface 12 is −40 ° C. to 170 ° C., and the temperature range of the intake passage wall outer surface 11 is −40 ° C. to 130 ° C.

  For this reason, the temperature differs between the first O-ring 2 and the second O-ring 3 at the maximum temperature at which the pressure measuring device is used. The first O-ring 2 is close to the outside surface 11 of the intake passage wall, and 130 ° C. outside air reaches the gap between the pressure measuring device 1 and the intake passage 10, so the temperature is about 130 ° C. The second O-ring 3 is close to the inner side surface 12 of the intake passage wall, and since the intake air at 170 ° C. reaches the gap between the pressure measuring device 1 and the intake passage 10, it is almost 170 ° C.

  On the other hand, since the low temperature use condition is a condition immediately after the engine start in the low temperature outside air, both the intake air temperature and the outside air temperature are −40 ° C.

  Under these temperature conditions, the first O-ring 2 uses a material that has a high compression set at a high temperature such as 170 ° C. but can ensure a low-temperature sealing property, and the second O-ring 3 is sealed at a low temperature. However, it is possible to realize a pressure measuring device that can be used at −40 ° C. to 170 ° C. by using an O-ring having a low compression set at a high temperature.

  In other words, a pressure measuring device that can be used between -40 ° C and 170 ° C is realized by providing a low-temperature-compatible O-ring and a high-temperature-compatible O-ring located closer to the pressure inlet than the low-temperature compatible O-ring. it can.

  A second embodiment of the present invention will be described with reference to FIG. Note that the description of the same configuration as that of the first embodiment is omitted.

  As shown in FIG. 5, the pressure device 7 is provided with a slit 8 between the first O-ring 2 and the second O-ring 3. The slit 8 can improve the thermal insulation between the first O-ring 2 and the second O-ring 3. When the outside air temperature is 130 ° C. and the intake air temperature is 170 ° C., heat from the intake side can be made difficult to be transmitted so that the temperature of the first O-ring 2 does not rise, and the first O-ring becomes high temperature. It becomes possible to suppress exposure. That is, high-temperature air is blocked by the second O-ring 3, and heat from the second O-ring 3 exposed to high temperature is transferred to the first O-ring 2 through the housing of the pressure measuring device. Can be prevented by the presence of the slit 8.

  A third embodiment of the present invention will be described with reference to FIG. Note that the description of the same configuration as that of the first embodiment is omitted.

  As shown in FIG. 6, the first O-ring 22 has a flat seal structure. FIG. 7 shows a state of the flat seal structure when the pressure measuring device 9 is arranged in the intake passage 10. In the case of the piston seal structure as shown in FIGS. 1 and 2, sealing is performed by inserting into the hole of the intake passage 10, whereas in the case of the flat seal structure, the pressure measuring device 9 needs to be pressed against the intake passage 10 with a screw or the like. There is. On the other hand, since the first O-ring 22 is in contact with the outside surface 11 of the intake passage wall, the first O-ring 22 is separated from the intake air flowing in the intake passage and becomes close to the outside air outside the intake passage. It becomes possible to separate from the ring 3 more. Therefore, there is an advantage that the influence from the high temperature intake to the first O-ring 2 is reduced.

  A fourth embodiment of the present invention will be described with reference to FIG. In addition, description is abbreviate | omitted about the two structures similar to Example 1,2,3.

  FIG. 8 shows a structure in which the flat seal structure of the third embodiment is combined with the slit 8 of the second embodiment. Each advantage is provided, and the influence of heat on the first O-ring 22 can be suppressed. Mounting in the intake passage is the same as in FIG.

  In each of the above-described embodiments, the mounting of the intake passage is shown as an example, but it is naturally applicable to the exhaust passage. Moreover, although the pressure apparatus was shown as an example, the same operation and effect are exhibited without impeding application to other apparatuses that measure the physical quantity of fluid.

DESCRIPTION OF SYMBOLS 1 ... Pressure measuring device 2 of this invention ... 1st O-ring 3 ... 2nd O-ring 4 ... Pressure measuring element module 5 ... Pressure inlet 6 ... Conventional pressure measuring device 7 ... 1st O-ring and 2nd Pressure measuring device 8 of the present invention provided with a slit between the O-ring of the present invention ... Slit 9 ... Pressure measuring device 10 of the present invention having the first O-ring having a flat seal structure ... Intake passage wall 11 ... Outside of the intake passage wall Side surface 12 ... Intake passage wall inner side surface 22 ... First O-ring 99 ... The first O-ring has a face seal structure, and a slit is provided between the first O-ring and the second O-ring. Pressure measuring device

Claims (6)

In the fluid physical quantity measuring device attached to the passage through which the fluid flows,
The first O-ring;
A second O-ring provided so as to be positioned closer to the inner wall side of the passage than the first O-ring;
The second O-ring is a fluid physical quantity measuring device that has a lower compression set at a higher temperature than the first O-ring.   2. The fluid physical quantity measurement device according to claim 1, wherein the first O-ring has better low-temperature sealing performance than the second O-ring.   The fluid physical quantity measuring device according to claim 1 or 2, further comprising a slit between the first O-ring and the second O-ring.   The fluid physical quantity measuring device according to any one of claims 1 to 3, wherein the first O-ring has a face seal structure when attached to the passage.   The pressure measuring device according to claim 1, wherein the fluid physical quantity measuring device is a pressure measuring device that measures a pressure between a supercharger and an intercooler.   A pressure measuring device comprising: a low-temperature-compatible O-ring; and a high-temperature-compatible O-ring disposed closer to the pressure inlet than the low-temperature-compatible O-ring.

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