JPH0725235U - Engine intake system - Google Patents

Abstract

(57) [Abstract] [Purpose] The structure is relatively simple and the filling efficiency in the high load region of the engine can be sufficiently secured, but in the low and medium load region, a strong tumble flow is generated in the cylinder. Provided is an engine intake device capable of being generated. As a projection for generating a deflected flow for generating a tumble flow in an intake port 8 of an engine, expansion and contraction that expands into the intake port 8 due to a differential pressure between a negative suction pressure in the intake port 8 and atmospheric pressure. The elastic bellows 13 is provided, and in the low and medium load region of the engine, the switching valve 16 causes the atmospheric pressure to act on one side of the elastic bellows 13 from the atmospheric pressure passage 17 through the operating pressure passage 14a to expand the elastic bellows 13. In the high load region of the engine, the switching valve 16 causes the suction negative pressure to act on one side of the elastic bellows 13 from the negative pressure passage 18 through the operating pressure passage 14a to elastically restore the elastic bellows 13. Inhaler.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an engine intake device capable of generating a strong tumble flow in a cylinder in a low and medium load region of an engine.

[0002]

[Prior art]

 As a measure to improve fuel economy and exhaust emission in a low load region where the throttle opening is small and the intake air amount is small accordingly in the engine operating region, the technology to generate the tumble flow in the intake mixture in the cylinder is the conventional technology. Is generally known. The generation of this tumble flow swirls the intake air-fuel mixture along the axial direction of the cylinder, and the tumble flow collapses in the latter half of the compression stroke to generate a strong turbulent flow. By igniting, turbulent combustion with high combustion speed and stable combustion can be obtained, which is effective for improving combustion in the low and medium load regions of the engine.

Such a tumble flow can be generated by supplying intake air passing through the intake port into the cylinder as a deflected flow along the wall surface of the intake port, that is, along the wall surface near the exhaust port. Therefore, conventionally, various intake devices have been proposed which generate a deflecting flow for generating a tumble flow in the intake port (see Japanese Patent Laid-Open No. 3-164523 and Japanese Utility Model Laid-Open No. 59-156122).

In the intake device described in Japanese Patent Laid-Open No. 3-164523, a raised bottom portion is provided on the inner bottom surface of the intake port to provide a deflected flow for tumble flow generation to the intake air passing through the intake port. It was created. The intake device disclosed in Japanese Utility Model Laid-Open No. 59-156122 divides the vicinity of the intake port into a main intake passage and a sub-intake passage, and the main intake passage is closed in the low load region of the engine. In the low load region of the engine where the on-off valve is closed, the mixed flow is sucked only from the auxiliary intake passage to obtain the deflected flow for tumble flow generation.

[0005]

[Problems to be solved by the device]

 By the way, the intake device described in Japanese Patent Laid-Open No. 3-164523 has a raised bottom portion on the inner bottom surface of the intake port, and in the engine high load region where the throttle is fully opened, the raised bottom portion serves as intake resistance. Therefore, there is a problem that the filling efficiency decreases. The intake device described in Japanese Utility Model Laid-Open No. 59-156122 is a structure that requires a partition wall that divides the vicinity of the intake port into a main intake passage and a sub intake passage, and an opening / closing valve for the main intake passage. Is relatively complex.

Therefore, the present invention has a relatively simple structure and can sufficiently secure the charging efficiency in the high load region of the engine, while generating a strong tumble flow in the cylinder in the low and medium load region. The objective is to provide an engine air intake system that is made possible.

[0007]

[Means for Solving the Problems]

 To this end, the present invention relates to an engine intake device having a projection for generating a deflected flow for generating a tumble flow in an intake port of the engine, wherein the projection is provided with a suction negative pressure in the intake port. The means is constituted by an elastic bellows that bulges into the intake port due to the pressure difference from the atmospheric pressure.

Further, the elastic bellows is also configured so as to be expanded into the intake port by the positive pressure from the pressure pump.

Further, a negative pressure passage for suction negative pressure may be connected via a switching valve to the working pressure passage for causing the elastic bellows to exert an atmospheric pressure or a predetermined positive pressure from a pressurizing pump. I am trying.

[0010]

[Action]

 In the engine intake system according to the present invention which employs such means, the elastic bellows expands into the intake port according to the differential pressure between the intake negative pressure and the atmospheric pressure in the intake port, and the tumble inside the intake port is tumbled. A deflected flow for flow generation is generated. Here, in the low and medium load range of the engine, since the suction negative pressure in the intake port is relatively large, the bulging amount of the extensible bellows becomes large, and the deflected flow in the intake port is correspondingly strong. Becomes Therefore, a strong tumble flow is generated in the cylinder.

Further, in the high load region of the engine, the suction negative pressure in the intake port decreases, and the amount of expansion of the elastic bellows decreases accordingly, so the intake resistance in the intake port decreases. The filling efficiency is sufficiently secured.

Here, in the case where the elastic bellows is expanded into the intake port by the positive pressure from the pressure pump, the expansion amount of the elastic bellows is increased or decreased by adjusting the positive pressure appropriately. , The strength of the tumble flow is also increased or decreased accordingly.

In addition, in the one in which the negative pressure passage of the suction negative pressure is connected through the switching valve in the middle of the positive pressure passage for applying a predetermined positive pressure from the atmospheric pressure or the pressure pump to the elastic bellows, By switching and connecting the positive pressure passage to the negative pressure passage, suction negative pressure acts on both sides of the elastic bellows, and the elastic bellows does not swell into the intake port.

[0014]

【Example】

 Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings. In FIG. 1, which shows an overall schematic structure of an engine intake device according to an embodiment, reference numeral 1 denotes an engine body in which a cylinder head 3 is assembled to a cylinder block 2, and a piston 5 is slidably attached to a cylinder 4 of the cylinder block 2. It is movably fitted. Further, the cylinder head 3 is formed with an intake port 8 communicating with the combustion chamber 7 via an intake valve 6 and an exhaust port 10 communicating with the combustion chamber 7 via an exhaust valve 9. On the mounting surface 3a of the cylinder head 3, an end of an intake manifold 11 for distributing the air-fuel mixture is continuously attached to the intake port 8. A spark plug 12 is installed in the center of the combustion chamber 7.

Here, the mounting surface 3 a of the cylinder head 3 is provided with an assembly hole 3 b located below the intake manifold 11 so as to communicate with the wall surface 8 a of the intake port 8 on the inner side of the bend. A nozzle 14 having a stretchable bellows 13 stretched at its tip is airtightly fitted and fixed in the assembly hole 3b via a seal ring 15.

The nozzle 14 has an operating pressure passage 14 a communicating with the inner surface side of the elastic bellows 13. The operating pressure passage 14 a communicates with the atmospheric pressure passage 17 and the intake manifold 11 via the switching valve 16. Is connected to the negative pressure passage 18. When the working pressure passage 14a is communicated with the atmospheric pressure passage 17, the elastic bellows 13 causes the differential pressure between the suction negative pressure in the intake port 8 and the atmospheric pressure acting during engine operation. When the working pressure passage 14a is communicated with the negative pressure passage 18 by bulging toward the wall surface 8b on the outer side of the bend, that is, the wall surface 8b near the exhaust port 10, the elastic bellows 13 causes the differential pressure acting on both surfaces thereof. When it disappears, it elastically returns along the wall surface 8a of the intake port 8.

The switching valve 16 is, for example, an electromagnetic three-way valve that is switch-controlled by an engine control unit (not shown), and connects the working pressure passage 14a to the atmospheric pressure passage 17 in the low and medium load region of the engine. In the high load region of the engine, the working pressure passage 14a is connected to the negative pressure passage 18.

Next, the operation of the intake system for an engine according to this embodiment having the above-described structure will be described. First, in the low and medium load region of the engine, the switching valve 16 connects the working pressure passage 14a of the nozzle 14 to the atmospheric pressure passage 17 by the switching control of an engine control unit (not shown). Further, at this time, in the intake stroke of the engine in which the intake valve 6 is opened, the suction negative pressure is acting in the intake port 8. Therefore, suction negative pressure and atmospheric pressure in the intake port 8 act on both surfaces of the elastic bellows 13, and the elastic bellows 13 moves from the inner wall surface 8a of the intake port 8 to the outer wall surface 8b of the intake bell 8. Bulges toward.

Therefore, the intake air-fuel mixture flowing from the intake manifold 11 into the intake port 8 is deflected and flows along the wall surface 8b on the outer side of the bend of the intake port 8, and the biased flow of the air-fuel mixture is directed to the piston 5. As it descends, it is sucked into the cylinder 4 along the cylinder wall surface on the exhaust port 10 side as shown by the arrow in FIG. 1, so that a tumble flow of the air-fuel mixture is generated in the cylinder 4.

In the low and medium load region of the engine, since the suction negative pressure in the intake port 8 is relatively deep, the elastic bellows 13 expands largely toward the wall surface 8b on the outside of the bend of the intake port 8. Put out. Therefore, the deflected flow generated in the intake port 8 becomes strong accordingly, and the tumble flow of the air-fuel mixture generated in the cylinder 4 also becomes strong.

Then, the tumble flow of the strong air-fuel mixture generated in the cylinder 4 collapses and becomes turbulent in the latter half of the compression stroke of the engine, so that the turbulence of the air-fuel mixture in the combustion chamber 7 increases. By igniting the spark plug 12 in this strongly turbulent mixture, stable and rapid combustion is performed, which improves the thermal efficiency and significantly improves the fuel efficiency and improves the exhaust emission. It

In the high load region of the engine, the switching valve 16 connects the working pressure passage 14 a of the nozzle 14 to the negative pressure passage 18 by the switching control of the engine control unit (not shown). Therefore, in the intake stroke of the engine in which the intake valve 6 is opened, the suction negative pressure in the intake port 8 and the suction negative pressure in the intake manifold 11 act on both surfaces of the elastic bellows 13, so that the elasticity is reduced. The bellows 13 elastically returns along the wall surface 8a of the intake port 8.

Therefore, in the intake stroke in the high load region of the engine, a large amount of the air-fuel mixture flowing into the intake port 8 from the intake manifold 11 passes through the intake port 8 without colliding with the elastic bellows 13. It is sucked into the cylinder 4 and the filling efficiency is sufficiently secured. The homogeneous air-fuel mixture thus sucked into the cylinder 4 with high charging efficiency is ignited by the spark plug 12 in the combustion chamber 7 in the latter stage of the compression stroke of the engine, so that good homogeneous combustion is performed. High output is obtained.

The atmospheric pressure passage 17 in this embodiment may be replaced by a pressure passage connected to an appropriate pressure pump. In this case, the operating pressure passage 14a of the nozzle 14 is connected to the pressurizing passage by the switching valve 16 in the low and medium load region of the engine, and the elastic bellows 13 is caused by the suction negative pressure in the intake port 8 and the pressurizing pump. Due to a pressure difference from a predetermined positive pressure, the intake port 8 bulges toward the wall surface 8b outside the bend. Therefore, the bulging amount of the extensible bellows 13 can be controlled by adjusting the pressure of the pressurizing pump, and by doing so, the strength of the tumble flow generated in the cylinder 4 can be freely adjusted. Further, even if the stretchable bellows 13 is a durable and firm one, it can be sufficiently expanded.

Further, the switching valve 16 and the negative pressure passage 18 in this embodiment may be eliminated and the working pressure passage 14a may be opened to the atmosphere. In this case, in the high load region of the engine, the suction negative pressure in the intake port 8 and the atmospheric pressure act on both sides of the elastic bellows 13, but the suction negative pressure in the intake port 8 is close to the atmospheric pressure. Since the pressure difference is shallow, the differential pressure is sufficiently small, and the bulging amount of the elastic bellows 13 can be reduced to such an extent that the filling efficiency does not decrease.

Structurally looking at the present embodiment, the nozzle 14 having the working pressure passage 14a is provided with the stretchable bellows 13 stretched at the front end of the nozzle 14 so as to be hermetically fitted in the mounting hole 3b of the cylinder head 3. Since the structure is fixed together, the structure is relatively simple compared with the conventional example of the structure that requires the partition wall that divides the intake port vicinity into the main intake passage and the sub intake passage and the opening / closing valve of the main intake passage. .

[0027]

[Effect of device]

 As described above, according to the present invention, the elastic bellows expands into the intake port according to the differential pressure between the intake negative pressure and the atmospheric pressure in the intake port, and the deflected flow for generating the tumble flow is generated in the intake port. In the low and medium load range of the engine, the suction negative pressure in the intake port is relatively large, so the bulging amount of the elastic bellows is large, and the deflection in the intake port is accordingly increased. The flow will be strong. Therefore, a strong tumble flow can be generated in the cylinder in the low and medium load region of the engine.

Further, in the high load region of the engine, the suction negative pressure in the intake port decreases, and the amount of expansion of the elastic bellows decreases accordingly, so the intake resistance in the intake port decreases. Therefore, the filling efficiency can be sufficiently ensured.

Here, in the case where the stretchable bellows is bulged into the intake port by the positive pressure from the pressure pump, the bulging amount of the stretchable bellows is adjusted to be increased or decreased by appropriately adjusting the positive pressure. Therefore, the strength of the tumble flow can be appropriately increased or decreased.

In addition, in the one in which the negative pressure passage of the suction negative pressure is connected through the switching valve in the middle of the positive pressure passage for applying the predetermined positive pressure from the atmospheric pressure or the pressurizing pump to the elastic bellows, By switching and connecting the positive pressure passage to the negative pressure passage, suction negative pressure acts on both sides of the elastic bellows, and the elastic bellows does not swell into the intake port. Therefore, it is possible to freely stop the generation of the tumble flow.

Structurally, the present invention is mainly composed of a stretchable bellows that bulges into the intake port due to the differential pressure between the suction negative pressure in the intake port and the atmospheric pressure. The structure is relatively simple as compared with a conventional example of a structure that requires a partition wall that divides the vicinity of the intake port into a main intake passage and a sub intake passage and an opening / closing valve for the main intake passage.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the overall schematic configuration and operation of an embodiment of an engine air intake device according to the present invention.

[Explanation of symbols]

 1 Engine Main Body 2 Cylinder Block 3 Cylinder Head 3a Mounting Surface 3b Assembly Hole 4 Cylinder 5 Piston 6 Intake Valve 7 Combustion Chamber 8 Intake Port 8a Bending Inner Wall Surface 8b Bending Outside Wall Surface 9 Exhaust Valve 10 Exhaust Port 11 Intake Manifold 12 Ignition Plug 13 Elastic bellows 14 Nozzle 14a Operating pressure passage 15 Seal ring 16 Switching valve 17 Atmospheric pressure passage 18 Negative pressure passage

Claims (3)

[Scope of utility model registration request] 1. An intake system for an engine having a projection for generating a deflected flow for generating a tumble flow in an intake port of the engine, wherein the projection has a difference between a suction negative pressure in the intake port and an atmospheric pressure. An intake device for an engine, comprising an elastic bellows that bulges into the intake port due to pressure. 2. The intake device for an engine according to claim 1, wherein the stretchable bellows is configured to swell into the intake port by a positive pressure from a pressure pump. 3. An operating pressure passage for applying an atmospheric pressure or a predetermined positive pressure from a pressurizing pump to the elastic bellows,
The intake system for an engine according to claim 1 or 2, wherein a negative pressure passage for negative suction pressure is connected via a switching valve.