JPH0749399Y2 - Intake negative pressure detection device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a suction negative pressure detection device for an internal combustion engine.

<Prior Art> Conventionally, as an electronically controlled fuel injection device for an internal combustion engine, a system that detects an intake pressure (intake negative pressure) PB as a state quantity of intake air and calculates a basic fuel injection amount Tp based on this is detected. There is one, and this method is called D-JETRO.

In such a system, an intake pressure sensor is provided in the intake manifold to detect the above intake pressure (intake negative pressure) PB.

A suction negative pressure detecting device for such an internal combustion engine is configured as shown in FIG. 6, and a pipe line 4 for extracting the pressure on the downstream side is located downstream of the position of the intake throttle valve 3 in the intake passage 2 of the engine 1. The intake pressure sensor 5 is connected via the.

<Problems to be Solved by the Invention> By the way, the intake pressure sensor 5 as described above prevents water, oil, gasoline, etc. from entering, and also prevents water in the pipeline 4 from being accumulated and frozen. Therefore, it is necessary to dispose the intake passage 2 at a position higher than the pressure outlet.

As a result, the arrangement position of the intake pressure sensor 5 is significantly limited, and the degree of freedom of the arrangement position is extremely low.

If water, oil, gasoline, or the like enters the intake pressure sensor 5 or if water in the pipeline accumulates and freezes, the pressure detection accuracy decreases or the pressure cannot be detected.

In view of the above-mentioned conventional problems, the present invention is designed to prevent water, oil, gasoline, and the like from entering the intake pressure sensor and to prevent water in the pipeline from accumulating and freezing. It is an object of the present invention to eliminate the necessity of arranging at a position higher than the pressure outlet and to increase the degree of freedom of the position at which the intake pressure sensor is arranged.

<Means for Solving the Problems> Therefore, the intake negative pressure detecting device for an internal combustion engine according to the present invention is provided with a pipe line for taking out a pressure on a downstream side of an intake throttle valve position of an intake passage of the engine, and for communicating with the pipe line. And an intake pressure sensor that is located above the volume chamber to detect the pressure in the chamber, and at least when the intake throttle valve is at a small opening, the intake passage upstream of the intake passage and the volume chamber. A line for introducing a small amount of air that communicates with the volume chamber main body is formed in a substantially circular shape, and a line for introducing a small amount of air is formed in a tangential direction of a substantially cylindrical peripheral wall of the volume chamber main body. It is configured to be connected to the volume chamber so as to flow in from.

<Operation> In this configuration, since a small amount of air flows into the volume chamber through the pipe line, water, oil, gasoline, etc. do not enter the volume chamber, and the water, oil, and
Gasoline or the like is discharged to the intake passage side through the pipe line, and water, oil, gasoline or the like is prevented from entering the intake pressure sensor.

Furthermore, since water does not accumulate in the pipeline, freezing of water in the pipeline is prevented.

Therefore, the pressure detection accuracy is not lowered and the pressure cannot be detected.

In particular, a small amount of air from the duct flows while flowing along the inner peripheral surface of the volume chamber body by flowing in from the tangential direction of the peripheral wall of the volume chamber body.

As described above, the small amount of air flows while swirling along the inner surface of the peripheral wall of the volume body, and the water in the small amount of air is subjected to a centrifugal force during this time and is pressed toward the inner surface of the peripheral wall of the volume chamber body to adhere to the inner surface of the peripheral wall.

The attached water is water, oil,
It will be discharged to the intake passage side together with gasoline and the like through the pipe line, and moisture in the trace amount of air will be prevented from entering the intake pressure sensor.

As a result, the intake pressure sensor does not necessarily have to be arranged at a position higher than the pressure outlet of the intake manifold, the arrangement position of the intake pressure sensor is not limited, and the degree of freedom of the arrangement position can be increased. it can.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings.

Referring to FIG. 1 showing a first embodiment of the present invention, an internal combustion engine 6
The intake pipe 7 is provided with an air cleaner 8 and an intake throttle valve 9 interlocked with an accelerator pedal from upstream to downstream. A branch line 11 from the intake pipe 7 to the intake manifold 10 is connected to a pipe line 13 for extracting pressure on the downstream side of the intake throttle valve 9 in the intake passage 12. A small chamber 14 as a volume chamber is connected to the conduit 13 so as to communicate therewith, and a pressure introducing portion 15a of an intake pressure sensor 15 for detecting the pressure of the small chamber 14 is provided in communication with the upper portion of the small chamber 14. .
Further, the air cleaner 8 on the upstream side of the intake throttle valve 9 in the intake passage 12
A conduit for introducing a small amount of air that connects the chamber directly downstream and the small chamber 14.
16 is provided, and an orifice 17 is provided at the communicating portion of the conduit 16 with the small chamber 14.

The diameter of the conduit 13 is set to be sufficiently larger than the diameter of the conduit 16 narrowed by the orifice 17.

The structure of the small chamber 14 is shown in FIG.

That is, the main body 14a of the small chamber 14 has a circular cross section, for example, a cylindrical shape with closed upper and lower ends.

The pressure introducing portion 15a is connected to the center position of the upper end of the small chamber body 14a. Also, the main chamber 1
A pipe 16 for introducing a small amount of air is tangentially connected to an upper position of the peripheral wall of 4a so that a small amount of air flows in from a tangential direction of the cylindrical peripheral wall of the small chamber body 14a.

Furthermore, the duct 1 for introducing the small amount of air in the peripheral wall of the small chamber body 14a.
6 A pressure-introducing pipe line 13 is tangentially connected to a lower position on the connection side.

Next, the operation and effect of the above configuration will be described.

The intake pressure (suction negative pressure) is guided to the small chamber 14 via the pipe line 13,
The intake pressure sensor 15 detects the intake pressure (intake negative pressure) by detecting the pressure in the small chamber 14.

Then, a small amount of air introduced from the portion immediately downstream of the air cleaner 8 on the upstream side of the intake throttle valve 9 of the intake passage 12 always flows into the small chamber 14 via the pipe 16.

In this case, except when the intake throttle valve 9 is fully opened, the pipeline 13 and the pipeline 13
With a pressure difference of 16, air flows through line 16. Further, at the time of full opening, air flows through the conduit 16 in the same manner as air flows through the intake passage 12.

As described above, since a small amount of air constantly flows into the small chamber 14 through the pipe line 16, water, oil, gasoline, etc. do not enter the small chamber 14, and the water that has entered the small chamber 14, Oil, gasoline, etc. are discharged to the intake passage 12 side through the pipe 13, and the intake pressure sensor 15 is prevented from entering these water, oil, gasoline, etc.

Furthermore, since water does not collect in the pipeline 13,
Freezing of water in 13 is prevented.

Therefore, the pressure detection accuracy is not lowered and the pressure cannot be detected.

As a result of the above, the intake pressure sensor 15 does not necessarily have to be arranged at a position higher than the pressure outlet of the intake passage 12, the intake pressure sensor 15 is not limited in its arrangement position, and the degree of freedom of this arrangement position is high. Can be increased.

According to the above-mentioned embodiment, since the diameter of the conduit 13 is set to be sufficiently larger than the diameter of the conduit 16 narrowed by the orifice 17, the flow of a small amount of air flowing into the small chamber 14 is reduced. The influence on the pressure detection can be reduced.

Here, on the peripheral wall of the small chamber body 14a, the conduit 1 for introducing a small amount of air
By connecting 6 in a tangential direction so that a small amount of air flows in from the tangential direction of the cylindrical peripheral wall of the small chamber main body 14a, the following actions and effects are achieved.

That is, the small amount of air from the conduit 16 flows in while circling along the inner peripheral surface of the small chamber body 14a by flowing in from the tangential direction of the peripheral wall of the small chamber body 14a.

In this way, a small amount of air flows while swirling along the inner surface of the peripheral wall of the small chamber body 14a, during which water in the small amount of air is subjected to centrifugal force and is pressed toward the inner surface of the peripheral wall of the small chamber body 14a and adheres to the inner surface of the peripheral wall. .

This adhered water is the water, oil,
It will be discharged to the intake passage 12 side together with gasoline or the like through the pipe line 13, so that the intake pressure sensor 15 is prevented from entering a small amount of water in the air.

If the bottom of the small chamber body 14a is formed in a funnel shape having a conical shape as shown in FIG. 3 and the pressure introducing conduit 13 is formed in the center of the funnel-shaped bottom, the above centrifugal separation effect can be obtained. This is preferable because it can be increased and the water can be separated and removed more effectively.

Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5.

In this embodiment, when the intake throttle valve 9 having a high suction negative pressure is fully closed, the minute amount of air described above is prevented from flowing, and the intake throttle valve 9
A small amount of air is allowed to flow only when the pressure difference between the upstream side and the downstream side of the is small.

In this case, a pipe 18 for introducing a small amount of air is provided to connect the upstream side of the intake throttle valve 9 in the intake passage 12 and the small chamber 14 when the intake throttle valve 9 is opened to a small degree.

With this configuration, when the intake throttle valve 9 is fully closed as shown by the solid line in FIG. 5, there is no pressure difference between the pipe line 13 and the pipe line 16, so that air does not flow through the pipe line 16.

On the other hand, as shown by the dotted line in FIG. 5, the intake throttle valve 9
At a certain small opening, the pipe line 18 communicates with the intake passage 12 on the upstream side of the intake throttle valve 9, so that a pressure difference between the pipe line 13 and the pipe line 16 occurs, and the intake air of the intake passage 12 is introduced into the small chamber 14. A small amount of air introduced from the upstream side of the throttle valve 9 flows in via the pipe line 18.

Therefore, it is possible to prevent water, oil, gasoline, and the like from entering the intake pressure sensor 15 and freezing of water in the conduit 13 without flowing air into the small chamber 14 more than necessary.

Also in this embodiment, the small chamber body is shown in FIG.
It is configured as shown in the figure, and similarly exerts the effect of separating and removing water and the like in the minute amount of air.

<Effects of the Invention> As described above, according to the present invention, the intake pressure sensor for detecting the pressure in the volume chamber communicating with the pipeline for extracting the pressure downstream of the intake throttle valve position in the intake passage of the engine is provided. Provided,
At least when the intake throttle valve is at a small opening, a pipe for introducing a small amount of air that connects the intake passage upstream side of the intake passage and the volume chamber is provided to prevent water, oil, gasoline, etc. from entering the intake pressure sensor. In addition, the freezing of water in the pipe for introducing the intake pressure is prevented, and it is possible to prevent a decrease in pressure detection accuracy and a state in which the pressure cannot be detected.

Therefore, the installation position of the intake pressure sensor is not limited, and the degree of freedom of the installation position can be increased.

In particular, since the pipe for introducing a small amount of air is connected to the volume chamber so that the small amount of air flows in from the tangential direction of the substantially cylindrical peripheral wall of the volume chamber main body, the centrifugal action in the volume chamber causes the small amount of air to flow. This is a great practical effect, which has an advantage that moisture and the like in the inside is separated and removed and the moisture and the like do not enter the intake pressure sensor.

[Brief description of drawings]

FIG. 1 is a schematic view of a first embodiment of an intake negative pressure detecting device for an internal combustion engine according to the present invention, FIG. 2 is a view showing a structure of a small chamber in the same embodiment, (a) is a perspective view, b) is a plan view,
FIG. 3 is a front view showing another example of the above small chamber, FIG. 4 is a schematic view of the second embodiment, FIG. 5 is a schematic view for explaining the operation of the second embodiment, and FIG. It is a schematic diagram of an example of the conventional suction negative pressure detecting device. 6 ... Internal combustion engine, 7 ... Intake pipe, 9 ... Intake throttle valve, 10 ... Intake manifold, 11 ... Branch part, 12 ... Intake passage, 13 ... Pressure introducing pipe line, 14 ... Small chamber, 14a ... Small chamber body, 15 ... Intake pressure sensor, 16, 18 ... Pipeline for introducing a small amount of air

Claims (1)

[Scope of utility model registration request] 1. A pipe line for taking out a pressure on a downstream side of an intake throttle valve position of an intake passage of an engine and a volume chamber communicating with the pipe line are provided, and the pressure of the chamber is located above the volume chamber. While providing an intake pressure sensor for detecting, at least when the intake throttle valve is at a small opening, a pipe for introducing a small amount of air is provided to connect the upstream side of the intake throttle valve of the intake passage and the volume chamber, and the volume chamber main body is substantially formed. A suction passage for an internal combustion engine, characterized in that it is formed in a circular cross section, and a pipe for introducing a small amount of air is connected to the volume chamber so that a small amount of air flows in from the tangential direction of the substantially cylindrical peripheral wall of the volume chamber main body. Pressure detector.