JPH0550069U - Intake device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Purpose] To promote atomization of fuel to stabilize combustion and improve exhaust gas conditions. [Composition] An air flow control valve which is provided in a location immediately downstream of the low-speed intake passage 30 branching from the middle / high-speed intake passage 29 and adjusts the amount of air flowing into the low-rotation intake passage 29. 31 and a jet passage 32 provided at the tip of the low rotation intake passage 29 for increasing the flow velocity of the air sucked into the low rotation intake passage 29 and blowing the air toward the surface of the intake port around the intake valve 21. Was established.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an intake device for an internal combustion engine.

[0002]

[Prior Art]

 FIG. 10 is a schematic configuration diagram of a main part of a conventionally known engine. In FIG. 10, in this engine, an intake pipe 5 having an intake passage 4 communicating with an intake valve 3 in a combustion chamber 2 of a cylinder head 1 and an exhaust gas communicating with an exhaust valve 6 in the combustion chamber 2 are also provided. An exhaust pipe 8 having a passage 7 is provided. In addition to the injector 9, an air cleaner 10, an air flow sensor 11, a throttle valve 12, an idle air control valve 13, an expansion pipe 14 and the like are provided in the intake passage 4.

Then, when the engine is started, fuel is injected into the intake port 15 by the injector 9 controlled by an electronic control unit (not shown), and when the intake valve 3 is opened, the intake valve 3 is opened. Along with the air passing through the passage 4, the throat portion 16 sucks the air into the combustion chamber 2.

By the way, the opening area of the intake port 15 in this type of engine is set to be equal to or larger than the area of the throat portion 16 in order to increase the intake air amount at the time of high rotation. Therefore, the flow velocity of the intake air in the intake port 15 and the throat portion 16 becomes slow when idling or at low speed.

[0005]

[Problems to be solved by the device]

 As described above, when the intake air flow velocity in the intake port 15 and the throat portion 16 becomes slow at the time of idling or at low speed, atomization of the injected fuel becomes worse, and the evaporation amount of the fuel attached to the surface decreases. This is exacerbated because the viscosity of the fuel becomes large at low temperatures. When the atomization of the fuel becomes worse, the fuel adheres to the surface of the intake valve 3 and the surface of the intake port 15 in a dew-like manner, and the combustion state deteriorates. Further, when the condensation further grows, this fuel sags the wall surface in the combustion chamber 2 and further deteriorates the combustion state. Then, this causes an increase in hydrogen gas (HC) and carbon monoxide (CO), which deteriorates the state of the exhaust gas and also deteriorates the combustion stability.

The present invention has been made in view of the above problems, and an object thereof is to provide an internal combustion engine having a structure capable of promoting atomization of fuel to stabilize combustion and improve exhaust gas conditions. To provide an intake device.

[0007]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, an intake system for an internal combustion engine according to the present invention has a middle / high rotation intake passage and a low rotation intake passage that join at a location immediately upstream of an intake valve. From the throttle valve provided directly downstream of where the low-speed intake passage is branched in the middle-high rotation intake passage, and the middle-high rotation intake passage in the low-speed intake passage An air flow rate control valve that is provided at a branch immediately downstream and that adjusts the amount of air that flows into the low-rotation intake passage, and a low-rotation intake passage at the tip of the low-rotation intake passage. A jet passage provided with an opening area smaller than the opening area, for increasing the flow velocity of the air sucked into the low-speed intake passage and blowing the air toward the surface of the intake port directly above the intake valve; With .

[0008]

[Action]

 According to this configuration, when the throttle valve is opened at the middle / high speed rotation, the intake air is blown or sucked into the combustion chamber along with the fuel through the middle / high rotation intake passage in the same manner as the conventional one. .. As a result, fuel and air can be sucked into the combustion chamber. On the other hand, if the throttle valve is fully closed or throttled and the air flow control valve in the low speed intake passage is opened during idling or low speed, intake air will flow into the low speed intake passage, which It is blown out through the jet passage toward the surface of the intake port just above the intake valve. In addition, the blown air hits the fuel adhering to the surface of the intake valve and the surface of the intake port around it, evaporates (atomizes) it, and is ejected from the injector. Blow or suck into the combustion chamber with fuel.

[0009]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 and 2 show a first embodiment of an intake system for an internal combustion engine according to the present invention. FIG. 1 is a vertical schematic side view of the same, and FIG. 2 is a transverse schematic top view thereof. 1 and 2, this engine is a multi-valve four-cycle engine, and has a substantially semicircular combustion chamber 23 that is sucked and exhausted by two intake valves 21 and two exhaust valves 22 (see FIG. 1). have. Although this engine has four cylinders 24, FIG. 1 shows only one of them as a representative. Further, each cylinder 24 has two throat portions 25 each closed by the intake valve 21, and two exhaust ports 26A and 26B each having one end closed by the exhaust valve 22. The throat portions 25 are connected to the same suction ports 27.

In addition, an intake pipe 28 having an intake passage is connected to the intake port 27. In the intake pipe 28, two intake passages, that is, an intake passage 29 for medium / high rotation and an intake passage 30 for low rotation are formed.

Of these, the medium-high rotation intake passage 29 is formed as a passage having a relatively large opening area.

On the other hand, the low rotation intake passage 30 is formed such that the upstream side is branched from the middle / high rotation intake passage 29, and the downstream side is joined again to the middle / high rotation intake passage 29. The downstream merging position is opened immediately upstream of the intake valve 21 and on the upper surface side of the medium-high rotation intake passage 29. In this opening portion 5, the jet passage 32 is provided for each intake passage 32. It is formed corresponding to the valve 21.

Each of the jet passages 32 has an opening area smaller than the opening area of the low-rotation intake passage 30, and the tip end side is opened so as to face the corresponding intake valve 21. Since the opening area of the jet passage 32 is smaller than the opening area of the low rotation intake passage 30, the air sucked into the low rotation intake passage 30 passes through the jet passage 32. When passing, the flow velocity of this air is increased and further blown toward the intake valve 21 while forming a vortex. Then, the blown air blows on the fuel adhering to the surface of the intake valve 21, the surface of the intake port 27 and the surface of the throat portion 25 around this, and vaporizes (atomizes) this fuel. Then, the fuel is injected or sucked into the combustion chamber 23 together with the fuel ejected from the injector 34. The jet passage 32 may be formed by directly using the hole formed in the intake pipe 28 or formed by inserting a separately formed pipe into the hole. In this embodiment, a structure formed by inserting a pipe is shown. As described above, in the case of using a pipe, it becomes easy to manage the opening size of the jet passage 32 and change the opening shape, and it becomes easy to obtain accuracy in the blowing direction.

Further, two air flow rate control valves 31 (see FIG. 2) are provided at a location immediately downstream of the middle / high-speed rotation intake passage 29, and the low air flow rate control valve 31 is used. The intake air amount passing through the rotary intake passage 30 can be limited.

On the other hand, a throttle valve 33 (see FIG. 2) is arranged at a location immediately downstream of the middle / high rotation intake passage 29 where the low rotation intake passage 30 is branched.

When the engine thus formed is started, fuel is injected into the intake port 27 by the injector 34 controlled by an electronic control unit (not shown), and the intake valve 21 is opened. At this time, this is sucked into the combustion chamber 23 from the slot portion 25 together with the air passing through the intake passage.

When the throttle valve 33 is open and the engine is operating at high or medium speeds, the air flow control valve 31 is throttled to a fully closed or half-opened state, and the intake air amount flowing in the low speed intake passage 30 is limited. .. Then, most of the intake air passes through the high rotation intake passage 30 and is sucked into the combustion chamber 23 from the throat portion 25 together with the fuel.

On the other hand, when the throttle valve 33 is controlled to be fully closed or a slight opening at the time of idling or low rotation, the air flow control valve 31 is fully opened or half opened, and most of the intake air is Flows into the low-speed intake passage 30. The air sucked into the low-rotation intake passage 30 has its flow velocity increased when passing through the jet passage 32, and is blown toward the intake valve 21 while forming a vortex. Then, the blown air adheres to the surface of the intake valve 21, the surface of the intake port 27 and the surface of the throat portion 25 in the vicinity thereof in a dew condensation manner (denoted by reference numeral 20 in FIG. 1). ) And is vaporized (atomized), and is blown or sucked into the combustion chamber 23 together with the fuel ejected from the injector 34. This allows the atomized fuel and air to be sucked into the combustion chamber 23.

The control of the throttle valve 33 and the air flow rate control valve 31 is controlled by an electronic control unit (not shown). Basically, the total intake flow rate is as shown in FIG. It is divided into the intake passage 29 and the low rotation intake passage 30. That is, FIG. 3 shows that, out of the total intake flow rate (A / N) that is taken in when the engine is driven, the flow rate flows through the middle / high rotation intake passage 29 and the low rotation intake passage 30 according to the accelerator opening θ. It is the diagram which showed the state where flow volume changes. As can be seen from FIG. 3, when the total amount of intake air flowing in the intake passage is represented by the solid line (a) in the figure, the two-dot chain line (b) in the figure indicates that the accelerator opening is small. The flow rate of air flowing through the intake passage 30 for low rotation is large, and the flow rate of air flowing through the intake passage 29 for medium / high rotation shown by the dotted line (c) in the figure is small. On the contrary, when the accelerator opening is increased, the flow rate of the air flowing through the low-rotation intake passage 30 indicated by the chain double-dashed line (b) decreases, and the middle of the portion indicated by the dotted line (c) in the figure. The flow rate of air flowing through the high-speed intake passage 29 increases.

Therefore, according to the intake device having the structure of this embodiment, the amount of fuel adhering to the surface of the intake port 27 and the surface of the intake valve 21 at the time of idling or low rotation is reduced, and atomization is promoted to burn the fuel. Since the fuel is sucked into the chamber 23, the combustion state becomes stable and improved. Furthermore, the combustion condition is stable and the misfiring is less likely to occur, so the exhaust gas condition is also improved. In addition, as the amount of fuel adhering to the surface of the intake port 27 and the surface of the intake valve 21 decreases, the surface of the intake valve 21 and the surface of the intake port 27 and the surface of the throat portion 25 around the intake valve 21 are reduced. It is possible to reduce the inhalation of non-atomized fuel that adheres in a dew condensation state, so that the combustion condition is further improved. As a result, carbon monoxide and the like contained in the exhaust gas are reduced, and the exhaust gas state can be improved.

4 and 5 show a second embodiment of the intake device for an internal combustion engine according to the present invention. FIG. 4 is a vertical schematic side view of the same, and FIG. 5 is a transverse schematic top view thereof. In FIGS. 4 and 5, the same reference numerals as those in FIGS. 1 and 2 indicate the same components as those in FIGS. 1 and 2. Further, in the structure of the intake device according to the second embodiment, two jet passages 32 are provided for each throat portion 25 in which the intake valve 21 is arranged, and two jet passages 32 are provided in each float portion 25. A heavy vortex is created. Of the two jet passages 32 corresponding to each throat portion 25, one jet passage 32 is directed toward the intake valve 21 while being substantially aligned with the fuel injection direction axis of the injector 34. The other jet passage 32 is formed so as to face another portion in the same throat portion 25.

Therefore, according to the intake device having the structure of the second embodiment, the air blown from each of the two jet passages 32 is blown toward different parts while forming a vortex in a wide range. Become. As a result, the fuel adhering to the surface of the intake port 27, the surface of the throat portion 25, the surface of the intake valve 21, etc. is well blown, and is vaporized (atomized) more efficiently and supplied to the combustion chamber 23. can do.

6 and 7 show a third embodiment of the intake system for an internal combustion engine according to the present invention. FIG. 6 is a vertical schematic side view thereof, and FIG. 7 is a transverse schematic top view thereof. 6 and 7, the same reference numerals as those in FIGS. 1 and 2 denote the same parts as those in FIGS. 1 and 2. In the structure of the intake device according to the third embodiment, the downstream merging position in the low rotation intake passage 30 is located immediately upstream of the intake valve 21 and on the lower surface side of the middle / high rotation intake passage 29. It is provided by opening it. Further, two jet passages 32 are provided at the tip of the low rotation intake passage 30 for each throat portion 25 in which the intake valve 21 is arranged. Of the two jet passages 32 corresponding to each throat portion 25, one jet passage 32 is provided toward the intake valve 21 so as to substantially coincide with the fuel injection direction axis of the injector 34, and the other jet passage 32. Are formed so as to face other parts in the same throat portion 25, and two vortices are formed by the air blown from each jet passage 32 as in the case of the second embodiment.

Therefore, even in the case of the intake device having the structure of the third embodiment, the air blown out from the two jet passages 32 is blown toward different parts while forming a vortex in a wide range. become. As a result, the fuel adhering to the surface of the intake port 27, the surface of the throat portion 25, the surface of the intake valve 21, etc. is well blown, and is more efficiently evaporated (atomized) and supplied to the combustion chamber 23. be able to.

8 and 9 show a fourth embodiment of the intake device for an internal combustion engine according to the present invention. FIG. 8 is a schematic vertical side view of the same, and FIG. 9 is a schematic cross sectional top view thereof. In FIGS. 8 and 9, the same reference numerals as those in FIGS. 1 and 2 indicate the same components as those in FIGS. In the structure of the intake system according to the fourth embodiment, the downstream merging position in the low-rotation intake passage 30 is located just upstream of the intake valve 21 as in the first and second embodiments. It is provided so as to be opened at a location and on the upper surface side of the intake passage 29 for medium / high rotation. Further, only one throat portion 25 to which the intake valve 21 is attached and one exhaust port 26 to which the exhaust valve 22 is attached are provided for each cylinder 24. Further, one jet passage 32 is provided toward the intake valve 21 at the tip of the low-rotation intake passage 30 so as to be substantially aligned with the fuel injection direction axis of the injector 34.

Therefore, even in the case of the intake device according to the structure of the fourth embodiment, the air blown out from the jet passage 32 has the surface of the intake port 27, the surface of the throat portion 25, the surface of the intake valve 21 and the like. The fuel adhered to these parts is evaporated (atomized) so as to more efficiently blow off the fuel, and the fuel is supplied to the combustion chamber 23.

[0027]

[Effect of the device]

 As described above, the intake system for an internal combustion engine according to the present invention can stabilize the intake of fuel and air into the combustion chamber with good responsiveness to the required engine speed. In addition, at the time of idling, air is blown out from the jet passage toward the intake valve, and this air blows off the fuel adhering to the intake port surface and the valve surface to evaporate (atomize). The amount of fuel that adheres to the valve surface in the form of dew condensation is reduced. Therefore, atomization is promoted, and the fuel is always sucked into the combustion chamber in the atomized state, so that the combustion state is improved. Further, the combustion condition is improved, misfiring is less likely to occur, and the exhaust gas condition is also improved. In addition, as the amount of fuel adhering to the intake port surface and the valve surface decreases, it is possible to reduce the intake of fuel adhering to the surface of the intake valve and the surface of the intake port around the intake valve. As a result, the amount of carbon monoxide and the like contained in the exhaust gas is reduced, the exhaust gas state can be improved, and it is expected that the fuel efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional side view of an intake device showing a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional top view of the intake device shown in FIG.

FIG. 3 is a diagram showing a state change of a flow rate flowing through a medium / high rotation intake passage and a low rotation intake passage according to an accelerator opening degree out of a total intake flow rate sucked when the engine is driven. is there.

FIG. 4 is a schematic vertical sectional side view of an air intake device showing a second embodiment of the present invention.

5 is a schematic cross-sectional top view of the intake device shown in FIG.

FIG. 6 is a schematic vertical sectional side view of an air intake device showing a third embodiment of the present invention.

FIG. 7 is a cross-sectional schematic top view of the intake device shown in FIG.

FIG. 8 is a schematic vertical sectional side view of an air intake device showing a fourth embodiment of the present invention.

9 is a schematic cross-sectional top view of the intake device shown in FIG.

FIG. 10 is a schematic configuration diagram of a main part showing an example of a conventional engine.

[Explanation of symbols]

 21 Intake Valve 23 Combustion Chamber 24 Cylinder 25 Throat Section 27 Intake Port 28 Intake Pipe 29 Medium / High Rotation Intake Passage 30 Low Rotation Intake Passage 31 Air Flow Control Valve 32 Jet Passage 33 Throttle Valve 34 Injector

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location F02M 69/00 310 U 9248-3G 69/04 R 9248-3G 9248-3G F02M 69/00 350 T

Claims (1)

[Scope of utility model registration request] 1. An intake system for an internal combustion engine having a middle-high rotation intake passage and a low-rotation intake passage that join together at a position immediately upstream of an intake valve, wherein the low-rotation inside the middle-high rotation intake passage is provided. A throttle valve provided immediately downstream of the low intake air passage for branching, and a throttle valve provided at a direct downstream location of the low intake air passage for branching the middle and high rotation intake passages. An air flow rate control valve for adjusting the amount of air flowing into the passage, and an opening area smaller than an opening area of the low rotation intake passage at the tip of the low rotation intake passage, An intake device for an internal combustion engine, comprising: a jet passage for increasing a flow velocity of air taken into the intake passage for blowing air toward a surface of an intake port immediately above the intake valve.