JPH0417771A - Intake air flow induction cover - Google Patents

Abstract

PURPOSE:To prevent the reverse flow and subsequent deposit of oil contained in blowby gas from an intake passage to an intake control valve at a bypass passage by providing an eccentric outlet for inducing a secondary intake flow through the bypass passage and intake control valve for injection mainly toward the downstream of an intake flow. CONSTITUTION:An intake flow induction cover 12 is so provided as to enclose the outlet 3 of an intake control valve 5. As a result, oil, even if splashed from a throttle valve 2 or the like, is prevented from directly reaching the aforesaid outlet 3. Furthermore, a secondary intake flow from the intake control valve 5 is introduced into the intake flow induction cover 12, and injected mainly toward the downstream of an intake flow through an outlet 13 at the eccentric position of the cover 12. According to the aforesaid construction, the eddy current of the secondary intake flow for entrapping oil does not occur near the outlet 13, and the reversed flow and ingress of oil into the intake flow induction cover 12 can be prevented.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides an intake control valve (ISC valve) for adjusting the idle rotation speed in the middle of a bypass passage that bypasses a throttle valve in an intake passage of an internal combustion engine. The invention relates to an intake system for an internal combustion engine of the type in which a blow-by gas inlet is opened in the intake passage. The present invention relates to a novel intake flow guide cover for preventing oil and the like from adhering to the intake control valve and causing trouble.

[Conventional technology]

A first prior art example belonging to this technical field is published in Japan Institute of Invention and Innovation, Branch No. 88-15312. In this example, the tip of the entrance of the bypass passage that bypasses the throttle valve in the intake passage of an internal combustion engine projects into the intake passage, and a cover called an oil cutter is attached around the protrusion of the entrance. Even if the oil contained in the blow-by gas flows in from the upstream side along with the intake air and travels down the inner wall of the intake passage, it does not flow into the bypass passage because of the oil cutoff, so the oil does not flow into the intake control valve. This means that there will be no intrusion.

Also, as a second conventional example, public technical number 89-1
There is one published in issue 0986. In this example, the ISC adjusts the idle intake flow rate flowing through the bypass passage.
By providing a vertical groove in the valve part of the valve or forming the vertical groove in a spiral shape, the flow velocity of air flowing between the valve seat part and the valve seat part is increased, and deposits such as oil attached to the outer periphery of the valve part are blown away. This prevents the intake control valve from clogging.

[Problem to be solved by the invention]

The first conventional example attempts to prevent oil from entering the bypass passage. The flow of intake air passing through the bypass passage (hereinafter, this will be referred to as the sub-intake flow).

), it is impossible to prevent deposits from occurring due to oil entering the intake control valve.

The inventors of the present invention have confirmed through experiments that the oil contained in the blow-by gas flows against the sub-intake flow and enters the intake control valve from the outlet side of the bypass passage.

The purpose of the second conventional example is to blow away deposits attached to the outer periphery of the valve part, and oil, etc. in blow-by gas that generates deposits is transferred from the outlet side of the bypass passage to the sub-intake flow. It does not prevent it from going backwards and entering the ISC valve. Rather, the oil that entered the bypass passage on the sub-intake air flow caused the IS.
It can be said that this prevents the C valve from clogging.

According to the research conducted by the present inventors, as shown in FIG. 15, when the throttle valve 2 in the intake passage 1 of the internal combustion engine is fully opened under full load and the engine speed is 2, QQQ rpm, the throttle valve 20 The intake flow in the intake passage 1 (referred to as the main intake flow) in both the front and rear is -like, and the intake flow at the outlet 3 of the intake control valve is -like.
For example, if the pressure at is about -15 mmHg, as shown in Fig. 16, under partial load when the throttle valve 2 is almost closed, the engine speed is at the same 2
．． Even at OOOrpm, the pressure near the outlet 3 of the intake control valve drops to about -200 anHg, and a vortex 4 as shown in FIG. 16 is generated near the outlet 3 of the throttle valve. If the vortex 4 swirls around the outflow direction of the sub-intake air flow that exits from the outlet 3 of the intake control valve, which is also the outlet of the bypass passage, the sub-intake air flow that flows out from the outlet 3 also swirls, and the swirl flow In order to create a lower pressure area in the center of the air, the oil that is captured on the surface of the throttle valve 2 and flows along with the main intake flow from a part of the periphery of the valve plate is
It is thought that the air gets caught up in the vortex 4 created around the outlet 30, enters through the outlet 3, and flows backward into the intake control valve.

The way oil gets caught up and flows into the intake control valve is as follows:
It has actually been observed and photographed successfully.

As shown in FIG. 17, the intake control valve 5 for the auxiliary intake flow
is provided in the bypass passage 6 that bypasses the throttle valve 2, even when the intake control valve 5 and the throttle valve 2 are installed in the intake passage 1 in the relationship shown in FIG. When the valve body 7 of the intake control valve 5 is provided with a spiral groove, or when the bypass passage 6 is connected tangentially to the intake control valve 5, the sub-intake flow becomes a vortex flow 4'. Therefore, the oil contained in the blowby gas flowing into the intake passage 1 from the blowby gas passage 8 leading to the crankcase of the internal combustion engine (not shown) through the branched inlet 9.9' is The outlet 3 is engulfed by the low pressure created by the vortex 4'.
It then enters the intake control valve 5, adheres to the valve body 7, the valve seat 10 surrounding it, etc., and seizes at high temperatures during the dead soak immediately after the engine stops, forming deposits and damaging the intake control valve 5.
It has been found that this can interfere with the normal operation of the engine, sometimes leading to engine malfunctions and other problems.

Based on the recognition of these new phenomena and facts, the present invention prevents the intrusion of oil from blow-by gas that flows backward from the outlet side of the bypass passage 6 toward the intake control valve 5 and forms deposits. This is the problem to be solved by the invention.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides an intake control valve that is inserted into a bypass passage that bypasses a throttle valve in order to adjust the idle rotation speed in an intake passage of an internal combustion engine through which blow-by gas is recirculated. 8 to the intake passage
provided so as to cover the mouth, and for guiding the sub-intake flow that has passed through the bypass passage and the intake control valve to eject the sub-intake flow primarily in the downstream direction of the intake flow flowing through the intake passage; Provided is an intake flow guiding cover characterized by having a biased outlet.

[For production]

In the present invention, since the intake guide cover is provided to cover the outlet of the intake control valve, even if oil is splashed from the throttle valve etc., it is prevented from directly reaching the outlet of the intake control valve, and the intake control valve is prevented from directly reaching the outlet of the intake control valve. The sub-intake air flow coming out of the valve is guided through the intake guiding cover and is ejected from the outlet provided at a biased position of the cover, mainly in the downstream direction of the intake air flow, so that a vortex of the sub-intake air flow is created near the outlet. This prevents oil from flowing backwards and entering the intake guide cover.

〔Example〕

FIGS. 1 to 14 show some embodiments of the present invention, and structural parts that are substantially the same as those in the prior art described in FIGS. 15 to 17 have the same reference numerals. is used.

First, in the first embodiment shown in FIGS. 1 to 3, blowby gas is guided from the crankcase or cylinder head cover of an internal combustion engine (gasoline engine) (not shown) through a blowby gas passage 8 to an intake passage 1. into the intake air flow from the inlets 9 and 9'. The inlet port 9 is positioned so that it opens upstream of the exhaust valve 9 during idle operation when the throttle valve 2 is closed, and the inlet port 9' similarly opens downstream. During idling operation when the throttle valve 2 is fully closed, the intake control valve 5
In order to adjust the flow rate of the sub-intake air flow passing through the bypass passage 6, the structure is such that the size of the gap between the valve seat 10 and the valve body 7 can be changed by a linear solenoid 11. The above configuration is substantially the same as the conventional one.

The feature of the first embodiment is that the short cylindrical intake flow guide cover 12 is shown in a bottom view in Fig. 2 and in a perspective view in Fig. 3.
This is because we have established The cover 12 is attached to the inner wall surface of the intake passage 1 and the road surface so as to cover the intake air jet section (outlet) 3 of the intake control valve 5.

The intake flow guiding cover 12 itself is formed by pressing or casting a metal plate, and has a notch 13 as an outlet extending over a portion of the bottom and side surfaces of its tip. The notch 13 opens toward the downstream side of the intake flow and the direction of gravity (downward) when the cover 12 is attached to the intake passage 1.

Since the first embodiment has such a configuration, the blow-by gas is guided through the passage 8, enters the intake passage 1 through the inlets 9 and 9', and joins the intake flow, but is not included in the blow-by gas. The lubricating oil adheres to the throttle valve 2 and the inner wall surface of the nearby intake passage 1, and reaches the vicinity of the outlet 3 of the intake control valve 5 along the wall surface as the throttle valve 2 is opened and closed. The auxiliary intake air flow passing through the bypass passage 6 passes through the intake control valve 5 and enters the intake flow guide cover 12 from 803, and is ejected into the main intake air flow from the notch 13 on the lower downstream side thereof.

Therefore, the ejected sub-intake air flow does not generate a vortex flow, and there is no possibility that oil will be drawn into the intake control valve 5 from the intake passage 1 and caused to flow backward.

The intake flow guide cover 12 prevents oil that had accumulated on the upstream side of the throttle valve 2 from flying off the main intake flow and scattering toward the outlet 3 of the intake control valve 5 when the throttle valve 2, which was closed during idling, opens. prevent it from hitting the outlet 3 directly. The oil is stopped on the outer shell of the intake flow guiding cover 12, and is carried to the combustion chamber of the engine by the auxiliary intake flow flowing out from the notch 13 and the main intake flow flowing out from the throttle valve 2, where it is rendered harmless. .

In this sense, the intake flow guide cover 12 has two functions: one is to guide the sub-intake air flow so that the oil is ejected in a manner that does not allow entrainment, and the other is to shield the intake control valve 5 from the oil that is scattered along with the main intake air flow. It can be said that it has two main functions. Further, as described above, when the intake flow guide cover 12 is provided on the inner wall surface of the intake passage 1 and the road surface, the cover 1
2 can be made to such an extent that the influence it has on the characteristics of the engine can be almost ignored. The reason why the notch 13 is provided in the direction of gravity on the downstream side of the intake air flow is to allow the sub-intake air flow to mix smoothly with the main intake air flow, and to prevent it from entering from the entry side of the bypass passage 60 or surrounding the cover 12. This is because even if a small amount of oil that has entered through the cover 12 remains inside the cover 12, it will fall into the intake passage 1 due to gravity when the engine is stopped.

FIG. 18 shows the results of an experiment conducted to confirm the effect of the intake airflow guiding cover 12, in which the engine speed was set at about 2. Keep the rpm at QQQ, and open the throttle valve 2 halfway to 7.
The amount of oil adhering to the valve body 7 and valve seat 10 of the intake control valve 5 was measured by repeating the process of holding the valve fully closed for 1 hour and then fully closed for 3 seconds. There is a significant difference in the amount of oil that adheres depending on whether or not the intake flow guide cover 12 is installed. By installing the cover 12, the amount of oil that adheres to the valve seat 10 is 92%, the valve body 7 is 82%, and the total amount of oil that adheres is 91%.
% reduction effect was observed.

Figure 4 shows the second embodiment. This example differs from the first embodiment in that it uses a positive crankcase ventilation system, which is often adopted in recent internal combustion engines. It is in.

The blow-by gas passage 14 communicating with the crankcase is
The blow-by gas passage 15 opens on the air cleaner side upstream of the throttle valve 2, and the other blow-by gas passage 15 opens on the downstream side of the throttle valve 2. It communicates with the engine's cylinder head cover or the crankcase.

As is well known, when the load is low, such as when the throttle valve 2 is closed and the throttle valve 2 is closed, a portion of fresh intake air enters through the passage 14 to ventilate the crankcase etc.
Blowby gas is sent into the intake passage 1 through the valve 16 and passage 15. Further, when the throttle valve 2 is opened under high load, the suction negative pressure in the passage 15 decreases, the PCV valve 16 closes, and the blow-by gas in the crankcase is sucked into the intake passage 1 from the passage 14. In either case, the blow-by gas contains oil mist, but the position of the opening that flows into the intake passage 1 changes between low load and high load.

However, even when using a PCV system as shown in FIG. 4, the intake flow guide cover 12 according to the present invention can prevent oil from entering the intake control valve 5. That is, at low load, blow-by gas flows into the intake passage l from the inlet 17 of the passage 15, which can be provided downstream of the throttle valve 2 and the intake control valve 5, so oil can flow into the intake control valve 5. Even if blow-by gas flows in from the inlet 18 of the passage 14 upstream of the throttle valve 2 under high load, the intake flow guiding cover 12 works as in the first embodiment. This is because oil can be prevented from entering the intake control valve 5.

Figures 5 to 14 show other embodiments of the intake flow guiding cover.
It is a manifestation of the species. First, in the intake flow guide cover 19 of the third embodiment, as shown in FIGS. 5 and 6, the shape of the notch 20, which is the outlet of the cover, is the same as shown in FIGS. 2 and 3. It is slightly different from that of the first embodiment, and is characterized in that it is provided obliquely to the direction of the sub-aerial flow jetting. This differs from the first embodiment in which the sub-intake flow is carried along with the main intake flow and flows out mostly downstream.This is different from the first embodiment in which the sub-intake flow is carried along with the main intake flow and flows out mostly downstream.In this embodiment, the component in the direction across the main intake flow is strengthened to promote mixing of the main and sub-intake flow. It is something that This has the effect of more evenly distributing the secondary inspiratory flow during inspiration.

The intake flow guide cover 21 of the fourth embodiment shown in FIGS. 7 and 8 has a through hole 22 on the downstream side of the intake flow in the short cylindrical side surface of the cover instead of a notch. The feature is that it is easier to process than when notches are provided.

The intake flow guide cover 23 of the fifth embodiment shown in FIGS. 9 and 10 has a small cylindrical outlet 24 attached to the through hole 22 of the fourth embodiment. By providing the outlet 24, the outflow direction of the sub-intake air flow is determined and it is smoothly guided into the main intake air flow, so it is almost impossible for oil to flow backward from the outlet and enter the cover 23. becomes impossible.

The intake flow guide cover 25 of the sixth embodiment shown in FIGS. 11 and 12 is similar to the first embodiment shown in FIGS. 2 and 3, and the third embodiment shown in FIGS. 5 and 6. In addition to having an external shape and cutout 26 similar to the intake flow guiding covers 12 and 19 of the example, the short cylindrical side surface of the cover 25 has a small diameter ( For example, an oil return hole 27 with a diameter of 0.5 mm is provided. The oil return hole 27 is used to drop oil that has entered from the entrance of the bypass passage 6 or a small amount of oil that has entered the interior of the intake flow guide cover 25 and remove it from the cover 25. It has been established.

Finally, the intake flow guide cover 28 of the seventh embodiment shown in FIGS. 13 and 14 has an air outlet 29 facing downstream of the intake air flow in a tangential direction with respect to the short cylindrical cover body, Moreover, the air outlet 29 is characterized in that a diaphragm 30 is provided. Note that this example also has an oil return hole 27 similar to that of the sixth embodiment. The reason why the outlet 29 is provided in the tangential direction is to allow the sub-intake flow to flow out by selecting a location where there is little oil flow, and the reason why the throttle 30 is provided is to prevent the sub-intake flow from ejecting from the outlet 29 Increase the flow rate,
This is to blow away oil that adheres to the vicinity of the outlet of the blow-off port. These functions prevent oil from entering the cover 28.

〔Effect of the invention〕

By implementing the present invention, oil in the blow-by gas flows backward from the intake passage toward the intake control valve in the bypass passage and adheres to it, forming a deposit that obstructs the operation of the vent valve and causes malfunction of the engine. This ensures that the engine remains in normal operating condition.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the first embodiment of the present invention, FIG. 2 is a bottom view of the main part, FIG. 3 is a perspective view, and FIG. 4 is a second embodiment of the present invention.
5 is a bottom view showing the main parts of the third embodiment; FIG. 6 is a sectional view thereof; FIG. 7 is a bottom view showing the main parts of the fourth embodiment; FIG. 9 is a bottom view showing the main parts of the fifth embodiment, FIG. 10 is a sectional view thereof, and FIG.
Fig. 1 is a bottom view showing the main parts of the sixth embodiment, Fig. 12 is a cross-sectional view taken along the line Xll-Xll, Fig. 13 is a bottom view showing the main parts of the seventh embodiment, and Fig. 14 is its XIV-XIV diagram. 15 is a sectional view showing the operating state of the conventional example, FIG. 1°6 is a sectional view showing another operating state, and FIG. FIG. 18 is a diagram showing the effects of the present invention in comparison with a conventional example. 1... Intake passage, 2... Throttle valve, 3
...Intake jet part (outlet) of the intake control valve, 4.4'...
- Vortex, 5... Intake control valve, 6... Bypass passage, 7... Valve body, 8-Blow-by gas passage, 9.9'... Inflow port, 10... Valve seat, 11.・・・
Linear solenoid, 12... Intake flow guide cover 13... Notch (outlet), 14.15... Blow-by gas passage, 16... PC
V valve, 17.18...Inlet, 19, 21.2
3.25.28...Intake flow induction cover 20.26...
・Notch (outlet), 22...Through hole, 24.29...Blowout port, 27...Oil return hole, 30...Aperture.

Claims (1)

[Claims] 1. In an intake passage of an internal combustion engine through which blow-by gas is recirculated, an intake control valve inserted in a bypass passage that bypasses a throttle valve to adjust the idle rotation speed is provided so as to cover the outlet to the intake passage. and has a biased outlet for guiding the sub-intake flow that has passed through the bypass passage and the intake control valve and ejecting the sub-intake flow primarily in the downstream direction of the intake flow flowing through the intake passage. An intake flow induction cover featuring