JPH0550031U - Intake device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Purpose] To improve engine response and exhaust gas conditions. [Structure] A control unit 40 is provided for controlling the opening / closing amount of a throttle valve 33 and an air flow control valve 31, and adjusting the amount of intake air flowing through an intake passage 29 for medium / high rotation and an intake passage 30 for low rotation. .

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an intake device for an internal combustion engine, and more particularly to an intake device for an internal combustion engine that can switch intake passages.

[0002]

[Prior Art]

 FIG. 9 is a schematic configuration diagram of a main part of a conventionally known engine. 9, 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 valve 6 communicating with the combustion chamber 2 are also provided. An exhaust pipe 8 having an exhaust 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. It is sucked into the combustion chamber 2 together with the air passing through the passage 4.

By the way, in this type of engine, when the volume of the intake passage or the like on the downstream side of the throttle valve 12 is large, when the throttle valve 12 is rapidly changed from the fully closed state to the vicinity of the fully opened state. In addition, it takes time for the resulting pressure change to be transmitted to the intake valve 3.

[0005]

[Problems to be solved by the device]

 As described above, if it takes time for the pressure change generated when the throttle valve 12 is suddenly switched from the fully closed state to the fully opened state to be transmitted as a change in the intake air amount to the combustion chamber 2, There was a problem that the intake air amount corresponding to the increase in the throttle opening could not be obtained, and the engine response (responsiveness) to the accelerator change deteriorated. On the other hand, when the throttle valve 12 suddenly changes from the fully open state to the fully closed state, even if the volume of the intake passage or the like on the downstream side of the throttle valve 12 is somewhat large, the negative pressure progresses early. In this case, there is a problem that the fuel control becomes relatively delayed, the fuel in the intake air becomes rich, the amount of hydrocarbons (HC), carbon monoxide (CO), etc. increases, and the state of the exhaust gas deteriorates. Therefore, in order to improve the engine response, it is possible to reduce the volume of the expansion pipe 14 etc. and reduce the overall volume on the downstream side of the throttle valve 12, but this method reduces the output at high engine speed. May lead to

The present invention has been made in view of the above problems, and an object thereof is to provide an intake device for an internal combustion engine having a structure capable of improving the engine response, the exhaust gas state, and the like.

[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 branched downstream location and that regulates the amount of air that flows into the low rotation speed air intake passage, and that controls the opening and closing amount of the throttle valve and the air flow rate control valve. It is provided with a control means for adjusting the amount of intake air flowing through the middle / high rotation intake passage and the low rotation intake passage.

[0008]

[Action]

 According to this configuration, the throttle valve that regulates the intake air amount that passes through the medium-high rotation intake passage and the air flow control valve that regulates the intake air amount that passes through the low rotation intake passage according to the accelerator opening and changes. It is possible to adjust the engine response by controlling the control valve and by controlling the two valves to obtain the intake air amount according to the accelerator opening and changes. When the throttle valve is suddenly changed from the fully open state to the fully closed state, the fuel concentration in the intake air can be adjusted by the low rotation intake passage and the air flow rate control valve.

[0009]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 6 and 7 show an embodiment of an intake device for an internal combustion engine according to the present invention, FIG. 6 is a schematic side view of a vertical section thereof, and FIG. 7 is a schematic top view of a cross section thereof. 6 and 7, the engine is a multi-valve type four-cycle engine, and has a substantially semicircular combustion chamber 23 (see FIG. 6) opened and closed by two intake valves 21 and two exhaust valves 22. ing. Although this engine has four cylinders 24, FIG. 6 shows 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 having one end closed by the exhaust valve 22 and joined together. The parts 25 communicate with the same intake port 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 located immediately upstream of the intake valve 21 and opens on the upper surface side of the middle / high-speed rotation intake passage 29. The jet passage 32 is provided in each of the openings. Is formed corresponding to.

It should be noted that the downstream side of the low rotation intake passage 30 may be opened to the middle / high rotation intake passage 29, and the jet passage 32 may not necessarily be provided. 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. At this time, the flow velocity of this air is increased and further blown out toward the intake valve 21. Then, the blown air is blown against the fuel adhering to the surface of the intake valve 21 and the surfaces of the intake port 27 and the surface of the throat portion 25 in the vicinity of the intake valve 21 to evaporate (atomize) the fuel. 2) and the fuel ejected from the injector 34 is blown into or sucked into the combustion chamber 23. As a result, fuel and air can be sucked into the combustion chamber 23. 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. 7) are provided immediately downstream of the middle / high-speed rotation intake passage 29, and the air flow rate control valve 31 controls the air flow rate. The intake air amount passing through the rotary intake passage 30 can be limited.

On the other hand, a throttle valve 33 (see FIG. 7) is arranged at a position 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). Further, when the intake valve 27 is opened, this is sucked into the combustion chamber 23 from the throat portion 25 together with the air passing through the intake passage.

The air flow control valve 31 and the throttle valve 33 are controlled according to the accelerator opening and change, and the basic operation is as follows. In other words, when the throttle valve 33 is opened and the engine is operating at a high or medium speed, the air flow rate control valve 31 is fully closed or half-opened, and the amount of intake air flowing into 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. Further, 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 out toward the intake valve 21. The blown air adheres to the surface of the intake valve 21, the surface of the intake port 27 and the surface of the slot portion 25 in the vicinity thereof in a dew condensation manner (indicated by reference numeral 20 in FIG. 6). The fuel is sprayed on and evaporated (atomized), and is blown or sucked into the combustion chamber 23 together with the fuel ejected from the injector 34. As a result, fuel and air can be sucked into the combustion chamber 23.

FIG. 8 shows the flow rate of the low-speed intake passage 30 and the flow rate of the low-speed intake passage 29 flowing through the middle-high rotation intake passage 29 according to the accelerator opening, out of the total intake air amount (A / N) drawn when the engine is driven. FIG. 6 is a diagram showing a state in which the flow rate flowing through and changes. As can be seen from FIG. 8, 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 θ is small. The air flow rate flowing through the low rotation intake passage 30 is large, and the air flow rate flowing through the middle / high rotation intake passage 29, which is indicated 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) is reduced, and the middle portion indicated by the dotted line (c) in the figure. The flow rate of air flowing through the high-speed intake passage 29 increases.

The above has described the basic control. However, the driving conditions and environment of the engine change every moment, and it is necessary to adopt the best driving method among these changes. Therefore, the air flow control valve 31 and the throttle valve 33 are optimally controlled in consideration of those conditions.

FIG. 1 is a conceptual diagram of a valve control system for controlling the air flow rate control valve 31 and the throttle valve 33. In FIG. 1, the air flow rate control valve 31 and the throttle valve 33 are connected to a control unit (CPU) 40 via a valve drive unit 41. The control unit 40 includes an intake air temperature signal, an atmospheric pressure signal, a crank angle sensor, a water temperature sensor, a cranking SW (abbreviation of "switch"; hereinafter the same), a power steering SW, an air conditioner SW, an ignition SW, an idle switch SW, Each output of the throttle sensor, air flow sensor, etc. is input.

FIG. 2 is a control circuit block diagram in the valve control system shown in FIG. In FIG. 2, in the control unit 40, a target rotation speed setting unit 42 for setting a target rotation speed (No) of the engine and a difference between the target rotation speed No and the actual engine rotation speed Ne are calculated. The gain calculation unit 43 and the valve drive unit 41 that drives and controls the air flow rate control valve 31 based on the opening degree of the air flow rate control valve 31 that only increases or decreases the intake air amount corresponding to the difference. In order to set the target rotation speed No in the target rotation speed setting unit 42, the rotation speed and the water temperature data 45 are used as the elements for controlling the air flow control valve 31, and the start correction data 48, In addition to air conditioner (A / C) SW data 49, power steering (P / S) SW data 50, highland correction data 51, intake air temperature correction data 52, throttle opening control value data set by the output of the throttle sensor 44 46 and each data correction based on the acceleration / deceleration control value data 47 are added and set. On the other hand, the opening degree θa of the throttle valve 33 is calculated and drive-controlled based on a well-known control program according to the engine speed Ne, the accelerator opening degree indicating the driver's intention to accelerate, the vehicle speed V, etc., and the description thereof is omitted.

FIG. 3 is a flowchart showing a procedure for controlling the air flow rate control valve 31 in the control circuit configuration. In FIG. 3, this valve drive processing is started in response to a time interrupt command every Δt. First, in step ST1, the latest throttle opening θn and the previous data of the control valve opening αn-1 of the air flow control valve 31 are fetched, and then the difference Δθ between the throttle valve opening and the pre-opening value is calculated. Yes (step ST2). Then, this difference Δθ and the judgment value θa for judging a sudden change are compared in step ST3. If the difference Δθ is smaller than the reference value θa, it is judged to be a steady state and the process proceeds to step ST4. Next, in step ST4, it is determined whether the difference Δθ is larger than 0. If it is determined that the difference Δθ is larger than 0, it is determined that the throttle valve 33 changes from closed to open, and the intake air amount A / N map in the steady state shown in FIG. From the characteristic curve L1, the intake air amount A / N corresponding to the current throttle opening θ is obtained (step ST5), and this is set as the control valve opening αn calculated this time (step ST6). On the other hand, when it is determined in step ST4 that the difference Δθ is smaller than 0, it is determined that the throttle valve 33 changes from open to closed, and the intake air amount A / N in the steady state shown in FIG. 4 is determined. From the characteristic curve L2 of the map, the intake amount A / N corresponding to the throttle opening degree θn at this time is obtained (step ST7), and this is set as the control valve opening αn calculated this time (step ST6).

On the other hand, when the difference Δθ is larger than the reference value θa in step ST3, the state at the time of rapid acceleration is set to step ST8, and it is determined in step ST8 whether the difference Δθ is larger than 0 or not. To do. If it is determined that the difference Δθ is greater than 0, it is determined that the throttle valve 33 changes from closed to open, and the intake air amount A / N map (characteristics) shown in FIG. From the curve L3), the intake air amount A / N corresponding to the throttle opening degree θn at this time is obtained (step ST9), and this is set as the control valve opening αn at this time. On the other hand, if it is determined in step ST8 that the difference Δθ is greater than 0, it is determined that the throttle valve 33 is changing from open to closed, and the map (b) of FIG. From the characteristic curve L4, the intake air amount A / N corresponding to the current throttle opening θn is obtained (step ST10), and this is set as the control valve opening αn calculated this time (step ST6).

Next, the process proceeds from step ST6 to step ST11. In step ST11, the difference Δα between the previous control valve opening αn −1 and the current control valve opening αn is detected, and this difference Δα is obtained. The corresponding valve drive amount V is obtained from the valve drive calculation map shown in FIG. 5 (step ST12), the air flow control valve 31 is driven based on the value of the valve drive amount V, and the process returns to the main routine (step ST13). ..

Therefore, according to the intake device having the structure of this embodiment, the throttle valve 33 for restricting the intake air amount passing through the medium-high rotation intake passage and the air restricting the intake air amount passing through the low rotation intake passage 30. By controlling the flow rate control valve 31 and controlling the two valves 31 and 33, the intake air amount according to the throttle opening change can be supplied to the combustion chamber of the engine with high responsiveness, and the engine output can be adjusted appropriately. Therefore, the optimum engine response can always be obtained. In particular, it is possible to mitigate the deceleration shock due to a sudden change in the intake air amount, and at the same time prevent the exhaust gas from deteriorating.

[0027]

[Effect of the device]

 As described above, according to the intake device for the internal combustion engine of the present invention, the intake air amount passing through the medium-high rotation intake passage is regulated according to the throttle opening, and the intake air amount passing through the low rotation intake passage is controlled. Is controlled by the air flow control valve, and the intake air amount according to the throttle opening can be secured with good responsiveness by controlling these two valves, and the deceleration shock due to the supply delay of the intake air amount during rapid acceleration / deceleration control is mitigated. The engine response can be kept good as well. Moreover, when the throttle valve is suddenly changed from the fully open state to the fully closed state, the rapid increase in the fuel concentration in the intake air can be moderated by the intake passage for low rotation and this air flow rate control valve. Can be prevented from worsening.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a valve control system in an intake device showing a first embodiment of the present invention.

FIG. 2 is a block diagram of a control circuit configuration in the above valve control system shown in FIG.

FIG. 3 is a flowchart showing an example of a processing procedure for controlling a valve in the control circuit shown in FIG.

FIG. 4 is a diagram showing an example of a map for determining an intake air amount based on a throttle opening.

FIG. 5 is a diagram showing an example of a valve drive calculation map.

FIG. 6 is a schematic vertical sectional side view of an intake device according to an 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 basic diagram of a flow rate of a flow rate through an intake passage for medium / high rotation and a flow rate through a low rotation intake passage according to a throttle opening, out of a total intake flow rate when the engine is driven by the intake device of the present invention It is a diagram showing a typical state change.

FIG. 9 is a schematic diagram of a main part of an example of a conventional engine.

[Explanation of symbols]

 21 Intake Valve 23 Combustion Chamber 24 Cylinder 27 Intake Port 28 Intake Pipe 29 Medium / High Rotation Intake Passage 30 Low Rotation Intake Passage 31 Air Flow Control Valve 33 Throttle Valve 34 Injector 40 Control Unit 41 Valve Drive Unit

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 intake air flow controlling the opening / closing amount of the throttle valve and the air flow rate control valve to flow through the middle / high rotation intake passage and the low rotation intake passage. An intake system for an internal combustion engine, comprising: a control unit for adjusting the amount of air.