JPS6263129A - Suction device for engine - Google Patents

Abstract

PURPOSE:To secure a smooth increment characteristic in engine output, by controlling each valve for opening or closing with the specified process according to the opening of an accelerator pedal, in case of a device which installs a shutter valve in a suction passage and a rotary valve in a bypass passage bypassing the said shutter valve, respectively. CONSTITUTION:In case of a suction valve which installs a shutter valve each to a suction passage 10a to be connected to a suction port 3 of each cylinder side by side, and also installs a rotary valve 18 in the bypass passage 15a installed so as to bypass the shutter valve 11a side by side, this rotary valve 18 is controlled by a rotary valve controlling device 35 inclusive of a planetary gear mechanism 23 to be interlocked with a cam shaft 25. That is to say, valve close timing is delayed to some extent according to an increase in the opening of an accelerator pedal, and valve open timing is controlled so as to be almost overlapped with the valve open timing of a suction valve 5. In addition, the shutter valve 11a is controlled so as to increase its valve opening more than the specified pedal opening by degrees according to an increase of the pedal opening by a shutter valve controlling device 40.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine intake system, and particularly to an improvement in the intake system for improving combustibility and reducing pumping loss in a low load range.

(Prior Art) Conventionally, as an intake III for this type of engine, for example, as disclosed in Japanese Patent Application Laid-Open No. 58-23245,
A shutter valve that opens when the accelerator pedal opening is equal to or greater than a predetermined opening is arranged in the intake passage, and a small-diameter bypass passage that bypasses the shutter valve rotates at a rotation speed ratio of 1/2 to the rotation of the camshaft. A rotary valve is installed, and in a low load range where the accelerator pedal opening is less than a predetermined opening, the shutter valve is closed to close the intake passage and supply intake air only from the bypass passage, increasing the flow rate of intake air and increasing the intake air flow rate. It is known to generate swirl to improve combustibility, and to reduce pumping loss and improve fuel efficiency by closing the rotary valve in the middle of the intake stroke. and,
In the above model, when the accelerator pedal is depressed from a low load range to a high load, the shutter valve opens and the intake passage is exposed, and intake air is supplied from this intake passage as well as the bypass passage. As a result, output can be improved.

(Problems to be Solved by the Invention) By the way, in an engine intake system equipped with a shutter valve and a rotary valve as described above, when opening the shutter valve at a predetermined opening degree of the accelerator pedal, the intake stroke of the rotary valve at low load. Pumping losses are reduced by the so-called mirror cycle, which is achieved by closing the valve midway, but when the accelerator pedal opening reaches a predetermined opening and the shutter valve is opened, the amount of intake air from the intake passage is reduced. Due to the supply, the intake end timing suddenly changes from the middle of the intake stroke to the end of the normal intake stroke, causing a sudden switch from the Miller cycle to the normal cycle (Otto cycle), causing torque shock.
This has the disadvantage that the engine output cannot be smoothly increased.

The present invention has been made in view of the above, and its purpose is to variably control the closing timing of the rotary valve, and to control the closing timing of the rotary valve at a predetermined accelerator pedal distance when the shutter valve starts to open. By shifting the intake end timing so that it coincides with the end of the intake stroke, the subsequent switching from the mirror cycle to the auto cycle due to the opening of the shutter valve can be performed smoothly, and the occurrence of torque shock in the engine can be prevented. The objective is to prevent this problem and obtain a smooth increase characteristic of engine output.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention includes disposing a shutter valve in the intake passage for opening and closing the intake passage, and providing a bypass passage for bypassing the shutter valve. A rotary valve is arranged to open and close the bypass passage,
The present invention is based on an engine intake system in which the above-mentioned stub valve is closed in a low load range, and the above-mentioned rotary valve is closed during the intake stroke. and rotary valve control means for delaying the closing timing of the rotary valve in accordance with an increase in the accelerator pedal opening, and causing the opening period of the rotary valve to substantially overlap the opening period of the intake valve at a predetermined accelerator pedal opening. and shutter valve control means for increasing the opening degree of the shutter valve from the predetermined accelerator pedal opening degree gradually in response to an increase in the accelerator pedal opening degree.

(Function) With the above configuration, in the present invention, in the low load range below the predetermined accelerator pedal opening, the shutter valve is in the open state and intake air is supplied only from the bypass passage, so the intake air flow rate becomes faster and the intake air Swirl is generated to improve combustion performance, and since the rotary valve closes during the intake stroke to create a Miller cycle, pumping loss is effectively reduced and fuel efficiency is improved.

In addition, when the accelerator pedal opening increases, the intake air amount gradually increases due to the gradual delay in the closing timing of the rotary valve in the above-mentioned low load range, and then, when the accelerator pedal reaches a predetermined level, the rotary valve opens. The period almost overlaps with the intake valve opening period, and the intake end timing shifts to the end of the intake stroke, and at this point the Shitotsuta valve begins to open, so the switch from the Miller cycle to the Otto cycle is performed smoothly. As a result, intake air is also supplied from the intake passage, increasing the amount of intake air, and as a result, the engine output increases smoothly without torque shock.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 and FIG. 2 show an embodiment applied to an intake system for a four-cylinder, four-cycle engine. In the same figure, 1 is the first
-An engine having fourth cylinders 18 to 1d, 2 is a combustion chamber formed in each cylinder 1a to 1 (1) of the engine 1,
An intake boat 3 and an exhaust port 4 are opened in the six combustion chambers 2, an intake valve 5 is located at the opening of the intake boat 3 to the combustion chamber 2, and an intake valve 5 is located at the opening of the exhaust boat 4 to the combustion chamber 2. An exhaust valve 6 is disposed at each of the exhaust valves 6.

Reference numerals 10a to 10d are intake passages whose one end communicates with the atmosphere and whose other end opens into each combustion chamber 2 via an intake boat 3 to supply intake air to each cylinder 1a to 1d of the engine 1; In the intake boats 3 and 1 of the intake passages 10a to 10d,
Shutter valve I that opens and closes each intake passage 10a to 10d
la to 11d are arranged, and each shutter valve 1
1a to 11d are serially connected to a valve shaft 12 disposed in the direction of the cylinder row, and are biased in the closing direction by a spring 14. In addition, each intake passage 10a to 1
Immediately downstream of the shita pulp 11a to 11d of 0d, fuel injection valves 13 for injecting and supplying fuel are respectively disposed.

Each of the above-mentioned intake passages 108 to 10d includes an intake passage 10
The first to fourth bypass passages 158 to 158 communicate the upstream side of the shutter valves 118 to 11d of a to 10d and the intake boat 3 by bypassing the shutter valves 118 to 11d.
15d is provided. Each bypass passage 158-1
5d has a passage cross-sectional area smaller than that of the intake passages 108 to 10d, and its downstream end opening opens toward the circumferential direction of the combustion chamber 2, directing intake air to the bypass passage 15.
By inhaling into the combustion chamber 2 through a to 15d,
An intake swirl is generated in the combustion chamber 2 along the circumferential direction.

In the middle of each of the bypass passages 158 to 15d, a single rotary valve 18 rotatably disposed within a cylindrical member 16 disposed in the cylinder row direction via a sleeve 17 is interposed in common. . The rotary valve 18
is made of a hollow body, and its end on the first cylinder 1a side is closed by fitting the rotation 111d131a of the sun gear 31 of the planetary gear mechanism 23, which will be described later, and its end on the fourth cylinder 1d side is closed. The section is closed with a closing member 19, and a bag-shaped intake air supply passage 20 is formed inside, and the outer periphery facing each bypass passage 15a to 15d is provided with an intake stroke of the corresponding air vR1a to 1d. An opening 18a is formed by cutting out a portion corresponding to the opening period of the intake valve 5 in the circumferential direction in an angular range corresponding to the rotation of the rotary valve 18. Bypass passages 15a to 15 on the downstream side of the valve 18
When the valve is opened and communicated with
We are making it possible to supply.

Further, the rotary valve 18 is connected to the end of the rotary pulp 18 on the first air [1a side] via a planetary gear mechanism 23.
A large diameter pulley 24 for rotational driving is connected, and the pulley 2
4, a belt 27 is wound around a small diameter pulley 26 provided at the end of a camshaft 25 arranged above the combustion chamber 2 in the direction of the cylinder row, and the rotation of the camshaft 25 causes rotary pulp 18 to rotate. The planetary gear mechanism 23 includes a ring gear 28 coaxially connected to the large-diameter boob 924, and three planetary gears 30 meshing with the ring gear 28 and interconnected by a carrier 29.
and a sun gear 31 that meshes with each of the planetary gears 30, and the gear ratio of the two-star gear mechanism 23 is
The ratio of the rotation speed of the rotary pulp 18 to the rotation speed of the rotary pulp 18 is set in advance to be "1". Further, each opening 18a of the rotary valve 18 opens each bypass passage 15a to 15d to a predetermined position in the middle of its intake stroke when the accelerator pedal is not depressed and the planetary gear 30 of the planetary gear mechanism 23 is at the initial position shown. It is pre-positioned to close at a certain time. Further, the two carriers of the planetary gear mechanism 23 are connected to an accelerator pedal (not shown) via a wire member 32, and when the accelerator pedal is depressed, the carrier 29 rotates clockwise in FIG. , by shifting the relative positions of the ring gear 28 and the sun gear 31, the position of each opening 18a of the rotary valve 18 is changed to a second position.
The valve closing timing of the rotary pulp 18 is gradually delayed as the accelerator pedal opening increases to a predetermined accelerator pedal opening as shown in FIG.
A rotary valve control means 3 whose valve closing timing coincides with the end of the intake stroke so that the valve opening period of the rotary valve 18 almost overlaps with the valve opening period of the intake valve 5.
5.

In addition, the upper one of the three planetary gears V30 of the planetary gear mechanism 23 has shutter valves 11a to 11.
d, a first link 36 extending in the direction of the valve shaft 12, and a longitudinal notch hole 37 formed at the end of the first link 36.
The ends of the valve shafts 12 of the shutter valves Iia to 11d are connected via a second link 39 having an engagement pin 38 that engages with the notch hole 37 of the first link 36.
The length is set to a length corresponding to the time the accelerator pedal opening reaches from the 110 II value to the predetermined accelerator pedal opening aOA. Therefore, as shown in FIG. 3, when the accelerator pedal is depressed, the first link 3
6 moves to the right in FIG. 2, the engagement pin 38 of the second link 39 moves within the notch hole 37 of the first link 36, and the shutter valves Ila to 11d maintain the closed state, When the predetermined accelerator pedal opening degree OA is reached, the second
The engagement pin 38 of the link 39 engages with the first link 36, and the valve shafts 12 of the shutter valves 11a to 11d rotate clockwise in FIG. A shutter valve control means 40 is configured to gradually increase the number of shutter valves accordingly.

In FIG. 2, reference numeral 41 indicates an assist air passage for supplying assist air to the vicinity of the injection port 13a of each fuel injection valve 13, and one end of the assist air passage 41 is connected to the intake passage 1.
The other end is connected to an air cleaner (not shown) disposed upstream of the collecting part of fuel injection valves 13, and has a large number of small holes 42a...
It communicates with the vicinity of the nozzle 13a of the fuel injection valve 13 through the bypass passages 15a to 1.56, and when the load is low, in which intake air is supplied only from the bypass passages 15a to 1.56, that is, when there is no intake air flow around the fuel injection valve 13, the fuel The fuel from the injection valve 13 is atomized by the assist air from the assist air passage 41, so that the air-fuel mixture within the combustion chamber 2 can be burnt efficiently.

Therefore, in the above embodiment, the shutter valve 1
During low load when 1a to 11d are in the closed state, intake air is supplied to the combustion chamber 2 only from the bypass passages 15a to 15d, so that the intake air flow rate increases and a swirl is generated in the intake air to improve combustibility. . In addition, since the intake end timing is set in the middle of the intake stroke by the low revalve 18, the pumping loss is reduced, and as a result,
Improved fuel efficiency is achieved. Moreover, in this case, as the intake ends in the middle of the intake stroke, the effective compression ratio in the next compression stroke decreases, and although the combustion temperature of the mixture decreases, a swirl is generated in the intake. Therefore, good flammability is ensured.

Further, when the accelerator pedal is depressed, the opening timing of the low-return valve 18 is controlled by the rotary valve control means 35 in accordance with the increase in the accelerator pedal opening, and the intake air amount is gradually increased, and then the predetermined accelerator pedal opening is increased. At the point in time, the closing timing of the rotary valve 18 coincides with the end of the intake stroke, and the opening period of the rotary valve 1B coincides with the end of the intake stroke.
When the opening period of the shutter valves 11a to 11d almost overlaps, from this point on, the opening degrees of the shutter valves 11a to 11d are gradually increased by the shutter valve control means 40 in accordance with the increase in the opening degree of the accelerator pedal, so that the amount of intake air gradually increases. As a result, the engine output is improved.

At that time, the start of opening of the shutter valves 11a to 11d is as follows.
Rotary valve 1 at the position of the predetermined accelerator pedal opening OA
Since the valve opening timing of 8 coincides with the end of the intake stroke, the switching from the so-called Miller cycle to the Otto cycle is performed smoothly and torque shock can be prevented, resulting in a smooth increase in engine output. can be ensured.

Furthermore, 〇-Taribal 718 is 1 for the camshaft 25:
Since it rotates at a rate of 1/1, the rotation rate is 1/1 with respect to the camshaft 25 as in the conventional case.
Compared to a rotary valve rotating at a rotational speed ratio of 2, the effective opening area of the bypass passages 15a to 15d during the opening period of the rotary valve 18 is increased, and the amount of intake air can be increased. Furthermore, due to the 1:1 rotation of the rotary valve 18 with respect to the camshaft 25, the positions of the openings 18a of the rotary valve 18 are different from the position of a predetermined cylinder (for example, the first cylinder 1a) and the cylinder two strokes later than this (the fourth cylinder 1d). Since the opening 18a corresponding to the predetermined cylinder (for example, the first air R9j1a') is located at a position where a phase difference of 180 degrees occurs in the rotation angle between the rotary valve 18 and the first bypass passage 15a on the downstream side of the rotary valve 18, Sometimes, 2 cylinders 1a and 2
The opening 18a corresponding to the fourth cylinder 1d whose stroke is delayed communicates with the fourth bypass passage 15d on the upstream side of the rotary valve 18, and the intake air flows from the fourth bypass passage 15d to the rotary valve 1.
Since the air is supplied to the first bypass passage 15a through the intake air supply passage 20 in the intake air supply passage 18, the structure can be simplified by eliminating the need for other piping.

Further, FIGS. 4 and 5 show other embodiments of the present invention, and in the above embodiment, instead of being applied to an engine equipped with a fuel injection valve 13, it is applied to an engine equipped with a carburetor. This is what I did. That is, the intake passages 10'a to 10'd
A carburetor 43 is arranged on the upstream side of the gathering part of the cylinders, and below the carburetor 43, a main bypass passage 44 communicating with each bypass passage 15'a to 15'd of each cylinder 1a to 1d is arranged. They are arranged in the row direction, and supply the air-fuel mixture from the carburetor 43 to the intake passages 10'a to 10'd gathering portion, and also to the respective bypass passages 15'a to 15'd through the main bypass passage 44. The other configurations are the same as those in the above embodiment. Therefore, as in the above embodiment, in the low load range, combustion performance is improved by high intake flow velocity and intake swirl, and while reducing pumping loss by closing the rotary valve in the middle of the intake stroke, the accelerator pedal opening is reduced. When the engine power increases, the mirror cycle can be smoothly switched to the normal automatic cycle, and a smooth increase in engine output can be achieved.

Incidentally, in the above embodiment, the rotary valve control means 35 and the shutter valve control means 40 are each constituted by a mechanical type equipped with a planetary gear mechanism 23, but other than that,
Rotary valve 18 and shutter valves 11a to 11
d may be electrically controlled depending on the degree of opening of the accelerator pedal.

(Effects of the Invention) As explained above, according to the engine intake system of the present invention, in a low load range, intake air is supplied only from the bypass passage to generate an intake swirl to improve combustibility. While reducing pumping loss by opening the valve during the intake stroke, when the accelerator pedal is depressed, the amount of intake air is controlled to delay the closing timing of the rotary valve, and the shutter valve opening is subsequently increased.1III@ The above-mentioned shutter valve opening time is set at the time when the rotary valve closing time coincides with the end of the intake stroke to smoothly switch from the so-called Miller cycle to the Otto cycle. , it is possible to prevent torque shock, ensure smooth increase in engine output, and improve engine performance.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show an embodiment of the present invention, and FIG. 1 is a cross-sectional view when applied to an intake system of a four-cylinder engine, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1. , FIG. 3 is a diagram showing the opening characteristics of the rotary valve and the shutter pulp with respect to an increase in the accelerator pedal opening, respectively. FIGS. 4 and 5 show other embodiments, and FIG. 4 is a diagram corresponding to FIG. 1. , FIG. 5 is a diagram corresponding to FIG. 2. 1...engine, 2...combustion! , 5... Intake valve;
10a to 10d11o'a to 10'd...Intake passage,
11 a to 11 d--Shutter valve, 158-
15d. 15'a to 15'd... Bypass passage, 18... Rotary valve, 18a... Opening, 20... Intake supply passage, 23... Planetary gear mechanism, 35... Rotary valve control means, 37... notch hole, 39... second
Link, 40... Shutter valve control means, 42...
・Main bypass passage. :Ij″jfu- Figure 1 Figure 5

Claims (1)

[Claims] (1) A shutter valve disposed in an intake passage to open and close the intake passage, and a rotary valve disposed in a bypass passage bypassing the shutter valve to open and close the bypass passage, and the shutter valve operates in a low load range. In this engine intake system, the rotary valve is closed in the middle of the intake stroke, and the rotary valve is delayed in accordance with an increase in accelerator pedal opening, and the rotary valve is opened at a predetermined accelerator pedal opening. rotary valve control means for causing a period to substantially overlap an opening period of the intake valve; and shutter valve control means for increasing the opening degree of the shutter valve from the predetermined accelerator pedal opening degree gradually in response to an increase in the accelerator pedal opening degree. An engine intake device characterized by comprising: