JP2699606B2 - Intake pipe pressure detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake pipe pressure detection device for detecting an intake pipe pressure of an internal combustion engine.

[Conventional technology]

2. Description of the Related Art Conventionally, a pressure sensor detects a pressure in an intake manifold downstream of a throttle valve to know an intake air amount of an internal combustion engine, and controls a fuel supply amount and the like to the internal combustion engine. The pressure sensor is usually connected to the intake manifold wall downstream of the throttle valve by a pressure introduction pipe, and the pressure in the intake manifold is introduced into the pressure sensor through the pressure introduction pipe.

By the way, pollutants such as blow-by gas, blow bio-oil, and EGR gas are mixed in the intake manifold, especially on the downstream side of the throttle valve, and when these contaminants enter the pressure sensor, the accuracy is reduced due to the adhesion of the contaminants, or Problems such as a decrease in durability arise. Therefore, Japanese Utility Model Laid-open No. Sho 57-138036 discloses that a fresh air introduction path is connected in the middle of a pressure introduction pipe and clean air is introduced into the pressure introduction pipe to prevent contaminants from entering the pressure sensor. A pressure detecting device has been proposed.

[Problems to be solved by the invention]

However, in the above-described conventional apparatus, since air is introduced into the pressure introducing pipe having a small diameter, the amount of introduced air cannot be increased so much to avoid an increase in pressure in the pressure introducing pipe.
Therefore, the entry of contaminants could not be completely prevented.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to supply sufficient clean air to reliably prevent contaminants from entering the pressure introduction pipe, and to prevent the contaminants from entering the pressure introduction pipe. It is an object of the present invention to provide an intake pipe pressure detection device for an internal combustion engine that can accurately detect the intake manifold pressure without causing a pressure increase.

[Means for solving the problem]

In order to achieve the above object, an intake pipe pressure detection device according to the present invention is a pressure detection device for detecting an intake pipe pressure downstream of a throttle valve of an internal combustion engine. A mixing chamber having an opening area larger than that of the pressure introduction port is formed at a connection portion between the pressure chamber and the intake pipe on the downstream side of the throttle valve. In order to generate an air flow from the mixing chamber toward the intake pipe on the chamber wall of the mixing chamber, an opening is formed in the pipe, downstream of an idle rotation adjusting screw of an idle port for securing a minimum intake air amount of the internal combustion engine. An air supply port communicating with the side port is provided.

[Action]

In the above configuration, an airflow from the mixing chamber toward the inside of the intake pipe is generated by the air supply port provided in the chamber wall of the mixing chamber. At this time, since the mixing chamber has an opening area larger than the pressure introduction port and is linearly opened in the intake pipe on the downstream side of the throttle valve, even if a large amount of air is introduced from the air supply port, the inside of the mixing chamber is not changed. There is almost no pressure rise. Therefore, sufficient air can be introduced into the mixing chamber, and the entry of contaminants is reliably suppressed.

The airflow is supplied through an idle port,
Since the air is used as air required for idling operation of the internal combustion engine, it does not affect the control of the internal combustion engine when the airflow is introduced.

〔Example〕

FIG. 1 shows a first embodiment of the present invention, and FIG.
FIG. In FIG. 1, reference numeral 1 denotes an intake manifold connected to an internal combustion engine E. The intake manifold 1 is connected to a throttle body 2 supported by a shaft 4 and provided with a throttle valve 3. The opening of the throttle valve 3 is adjusted by the rotation of the shaft 4 connected to the accelerator pedal by a mechanism not shown, and the amount of air supplied to the internal combustion engine E is adjusted.

A semiconductor pressure sensor 5 is connected to a pipe wall of the throttle body 2 on the downstream side of the throttle valve 3. The main body housing 6 of the pressure sensor 5 is a cylindrical body which is closed at one end and has a pressure chamber 7 formed therein, and a pressure introducing port 9 having a part of an opening-side end face protruding in a cylindrical shape and a flange 10 (second
Figure) is provided. A pressure detector 8 having a known silicon diaphragm is disposed in the pressure chamber 7. On the other hand, the throttle body 2 has a hole 18 and a screw hole 19 (second
Figure) is provided, and the flange 10 of the pressure sensor 5
It is screwed via an annular gasket 31.

The space inside the pressure introduction port 9 is a mixing chamber 15 composed of a barbed wall 11, a spacer stopper 12, a spacer 13, and a metal filter 14 from the throttle body 2 side.
The mixing chamber 15 communicates with the pressure detector 8 in the pressure chamber 7 through a pressure inlet 17. However, holes for introducing pressure are formed in the spacer stoppers 12 and the spacers 13, and these holes are arranged so that their centers are the same or are shifted from each other to form a maze. Thus, the pressures in the throttle body 2 and the intake manifold 1 are introduced into the pressure detector 8 through the mixing chamber 15 and the pressure inlet 17.

The throttle body 2 is provided with an idle port 20 through which air required to maintain the idle rotation of the internal combustion engine E flows, and an adjusting screw 21 for adjusting the amount of air flowing into the idle port 20. The idle port 20 is divided into a main flow path 23 having an orifice 22 and a bypass 24 downstream of the adjusting screw 21. The bypass 24 is connected to an intake port 16 provided in the pressure sensor 5 via a gasket 25 without a gap so as to communicate with the mixing chamber 15 of the pressure sensor 5.

As a result, a part of the clean air upstream of the throttle valve 3 introduced into the idle port 20 is introduced into the mixing chamber 15 from the air supply port 16 through the idle port 20 and the bypass 24. At this time, if the amount of air supplied from the air supply port 16 is small, the entry of pollutants cannot be completely controlled, and if it is too large, the accuracy of detecting the pressure in the throttle body 2 may be deteriorated. 3-30 / m air introduction volume
in (when the internal combustion engine is idle), desirably 3 to 10 / min
The size of the feed port 16 and the diameter of the orifice 22 are adjusted so that In the present embodiment, the orifice 22 is φ5.5.

Further, when the opening area of the mixing chamber 15 into the throttle body 2 is small, the air supplied from the air supply port 16 causes
Since it is considered difficult to perform accurate pressure detection, when the mixing chamber 15 is formed in a cylindrical shape as in this embodiment, the diameter is set to 4 mm or more, preferably about 6 to 15 mm. Is good. This corresponds to 4 to 5 times the opening area of the pressure inlet 17.

In order to minimize the ingress of contaminants, the mixing chamber 15
The distance from the open end to the pressure inlet 17 is at least twice the diameter of the mixing chamber 15.

Next, the operation of the pressure detecting device of the first embodiment will be described.

In the above configuration, air is introduced from the throttle body 2 through the intake manifold 1 to the internal combustion engine E. In order to control the output of the internal combustion engine E, the throttle valve 3
, The pressure on the downstream side of the throttle valve 3 is lower than the pressure on the upstream side.

The pressure on the downstream side of the throttle valve 3 acts on the mixing chamber 15 of the pressure sensor 5. Therefore, the pressure difference between the upstream side and the downstream side of the throttle valve 3 causes a pressure difference between the upstream side and the downstream side of the throttle valve 3. Is always introduced from the air supply port 16 through the idle port 20 and the bypass 24.

In general, the pressure in the intake pipe downstream of the throttle valve 3 greatly fluctuates due to the pulsation of the intake air of the internal combustion engine E, and also fluctuates greatly when the throttle valve 3 is opened and closed. On the other hand, contaminants such as blow-by gas, blow-bio-oil and EGR gas are usually introduced downstream of the throttle valve 3 and are uniformly dispersed therein. For this reason, gas conversion is also performed in the mixing chamber 15 in accordance with the pressure fluctuation, and contaminants try to enter the mixing chamber 15. However, as described above, pure air upstream of the throttle valve 3 from the air supply port 16 is always introduced into the mixing chamber 15 to generate an airflow from the mixing chamber 15 toward the downstream side of the throttle valve 3. Then, a clean air layer is formed near the boundary between the pressure chamber 17 and the pressure inlet 17 communicating the pressure detector 8. Therefore, contaminants are blocked by the layer of clean air and cannot enter the pressure inlet 17, and only clean air flows into and out of the pressure detector 8. In addition, the diameter of the mixing chamber 15 is sufficiently larger than the pressure introduction port 17,
And since it opens directly into the throttle body 2,
Even if a large amount of air is introduced from the air supply port 16, the pressure in the mixing chamber 15 hardly increases. Therefore, sufficient air can be introduced into the mixing chamber 15, and the entry of pollutants can be reliably prevented, and at the same time, the pressure downstream of the throttle valve 3 in the throttle body 2 can be accurately detected.

Further, the installation of the rattle-shaped wall 11 and the metal filter 14 can more reliably prevent contamination from liquid film-like oil, carbon particles, and the like.

Further, in this embodiment, since the pressure introduction pipe for connecting the pressure sensor to the throttle body is eliminated, and the pressure sensor body is directly connected to the throttle body with the flange, the number of parts is small and the number of parts is reduced. Is also easy.

FIG. 3 shows a second embodiment of the present invention, and FIG. In the present embodiment, holes 26, orifices 28, main passages 29, bypasses 30, and screw holes 27 are provided on the intake manifold 1 side.
(FIG. 4) and the pressure sensor 5 is connected. According to the present embodiment, the bypass manifold 30 is processed on the intake manifold 1 side, and the throttle body 2 does not need to be processed at all. This is advantageous in the case of a throttle body in which the pressure sensor 5 is connected to only a few places. Also, the main flow path 2
It goes without saying that only one of the bypass 30 and the bypass 30 may be processed to the intake manifold 1 side.

FIG. 5 shows a third embodiment of the present invention. In this embodiment, the idle port 20 and the air supply port 16 of the pressure sensor 5 are connected by piping.
It is communicated at 34. Adjustment screw 21 for idle port 20
A bypass 33 having a pipe 32 is projected from the downstream toward the atmosphere. An air supply pipe 35 is provided at the air supply port 16 of the pressure sensor 5.
32 is communicated with a pipe 34. This is an effective means when it is not possible to perform processing for directly connecting the bypass 33 to the throttle body 2 to the air supply port 16 of the pressure sensor 5. Also, the main flow path 23 having the pressure sensor 5 and the orifice 22 is
Like the embodiment, it may be provided on the intake manifold 1 side.

In this embodiment, as shown in the first and second embodiments, the metal filter 14, the spacer 13, the rattle-shaped wall 11 and the like are not installed in the mixing chamber 15, but such a simple cylinder is used. A sufficient effect can be obtained even in the shape of a circle.

FIG. 6 shows a fourth embodiment of the present invention. In this embodiment, a separately mounted pressure sensor 36 is screwed to the throttle body 2 with a stay 37 and a screw 38. The idle port 20 is divided into a main flow path 23 having an orifice 22 and a mixing chamber 39, and a pressure inlet 41 having a pipe 40 from above the mixing chamber 39.
And communicate with the pressure sensor 36 via the pipe 42. Thus, since the mixing chamber 39 is provided on the throttle body 2 side, a separately mounted pressure sensor can be directly mounted. Here, a metal filter or the like may be provided in the mixing chamber 39 as in the first and second embodiments.

Further, it goes without saying that the pressure sensor 36, the mixing chamber 39 and the like may be provided on the intake manifold 1 side.

In the second to fourth embodiments, the operation and effect are the same as those shown in the first embodiment.

FIG. 7 shows a fifth embodiment of the present invention, and FIG. In the present embodiment, in the pressure sensor 5, clean air is introduced from the downstream side of the metal filter 14. For this reason, the air supply port 16 is provided in the middle of the pressure introduction port 9, and an air supply hole 46 is opened in the spacer 45.
The O-rings 43 and 44 are hermetically sealed so that clean air can be introduced from the idle port 20 from the side of the mixing chamber 15. According to the present embodiment, the distance from the position of the air supply port 16 to the pressure introduction port 17 can be made longer than in the first and second embodiments, and the influence of the introduced clean air can be further reduced. The accuracy of the pressure is improved.

Further, similarly to the second embodiment, the pressure sensor 5, the bypass 2
5. Of course, the main flow path 23 and the like may be provided on the air supply manifold 1 side.

FIG. 9 shows a sixth embodiment of the present invention, and FIG. In the present embodiment, in the pressure sensor 5, clean air is introduced from the side of the metal filter 14. For this reason, an air supply port 16 is provided at a position corresponding to the side surface of the filter 14 of the pressure introduction port 9, and is sealed by O-rings 43 and 44.

The operation and effect of this embodiment are the same as those of the fifth embodiment.

〔The invention's effect〕

According to the present invention, since a mixing chamber having an opening area larger than the pressure introduction port to the pressure detection body is provided at the connection between the pressure sensor and the intake pipe, clean air is introduced into the mixing chamber. Even if a large amount of air is introduced, the pressure in the mixing chamber hardly increases due to the introduced air, and the pressure in the intake pipe can be accurately detected. In addition, since a large amount of air can be introduced, entry of contaminants into the pressure sensor can be reliably prevented, and durability can be greatly improved.

Further, in order to regulate the idle speed of the internal combustion engine E, the amount of intake air is reduced, and thereafter, clean air in the idle port is introduced. Therefore, it is necessary to newly introduce clean air from the outside to prevent contamination of the pressure sensor. Disappears. Therefore,
It is possible to prevent the state of the engine speed due to the introduction of clean air to the pressure sensor.

Furthermore, even with an extremely small engine having a small intake air amount, clean air for preventing contamination of the pressure sensor can be sufficiently ensured.

[Brief description of the drawings]

FIG. 1 is an overall sectional view of a pressure detecting device according to a first embodiment of the present invention, FIG. 2 is a view taken in the direction of arrow A of FIG. 1, and FIG. 3 is a pressure detecting device according to a second embodiment of the present invention. 4, FIG. 4 is a view taken in the direction of the arrow A in FIG. 3, FIG. 5 is a whole sectional view of a pressure detecting device showing a third embodiment of the present invention, and FIG. 6 is a fourth embodiment of the present invention. FIG. 7 is an overall sectional view of a pressure detecting device showing a fifth embodiment of the present invention, FIG. 8 is a view taken in the direction of the arrow A of FIG. 7, and FIG. FIG. 10 is an overall sectional view of a pressure detecting device according to a sixth embodiment of the present invention;
The figure is a view on arrow A of the one shown in FIG. 1 ... intake manifold, 2 ... throttle body, 3 ...
Throttle valve, 5… Pressure sensor, 8… Pressure detector, 9…
Pressure inlet port, 11 …… Rice wall, 12 …… Spacer stop, 1
3 ... spacer, 14 ... metal filter, 15 ... mixing chamber, 16
…… Air supply port, 17 …… Pressure inlet port, 20 …… Idle port, 2
1 Adjustment screw, 22 Orifice, 23 Main flow path, 24
Bypass, E ... Internal combustion engine.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Toru Kosuda 14 Iwatani, Nissan-shi, Nishio-shi, Aichi Prefecture Inside Nissan Automobile Parts Research Institute Co., Ltd. (56) References JP-A-63-212737 (JP, A)

Claims (2)

(57) [Claims] 1. A pressure detecting device for detecting a pressure in an intake pipe on a downstream side of a throttle valve of an internal combustion engine, a connection portion between a pressure inlet for introducing the pressure in the intake pipe into a pressure sensor and an intake pipe on a downstream side of the throttle valve. A mixing chamber having an opening area larger than the pressure introduction port is formed, and the pressure introduction port is communicated with the mixing chamber, and the mixing chamber is opened in the suction pipe. Has an air supply port communicating with a downstream port of an idle rotation adjusting screw of an idle port for securing a minimum intake air amount of the internal combustion engine in order to generate an air flow from the mixing chamber toward the intake pipe. Characteristic intake pipe pressure detector. 2. The intake pipe pressure detecting device according to claim 1, wherein at least one of a filter and a barbed wall is provided in said mixing chamber.