JPS63179125A - Intake device for engine - Google Patents

Abstract

PURPOSE:To promote variation of pressure and to improve output of engine, by communicating intake paths of different cylinders each other in the downstream of a timing valve and setting the communication length such that pressure wave can be propagated with an operation interval between the cylinders under specific rotary region. CONSTITUTION:An engine 1 is provided with a plurality of cylinders 1F, 1R, and a rotor 3 is supported on an eccentric shaft 4 in the housing 2 of said cylinders 1F, 1R such that it can perform planetary rotation. An intake path 8 for supplying intake air to said cylinders 1F, 1R is provided with an air cleaner 9 and an intake quantity sensor 10 at the end of upstream, and a plurality of intake paths 11, 12 are branched in the way. In such arrangement, independent intake paths 12a, 12b for said cylinders 1F, 1R in the downstream of a timing valve 18 arranged in a second intake path 12 are communicated each other through a communication path 23. the length of the communication path 223 is set such that pressure wave is propagated with an operation interval between said cylinders 1F, 1R under specific rotary region.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an intake system for an engine equipped with a timing valve in an intake passage.

(Prior Art) Conventionally, there has been an intake system in which a timing valve is provided in the intake passage of an engine, and the opening/closing timing of this timing valve is adjusted separately from the intake valve to perform intake m control. It is publicly known as seen in Japanese Patent No.-55329.

In the preceding example, when the load is low or when knocking occurs, the timing valve is closed earlier than the intake valve to reduce the intake flow, and the intake valve is opened to reduce intake air into the combustion chamber in the latter half of the intake stroke. Prevents inhalation of gas, reduces pumping loss, and suppresses knocking due to lower compression ratio! ll.

On the other hand, there is also a technique in which the intake passage of an engine is configured with a natural intake passage and a supercharging passage, and a timing valve is provided in the supercharging passage to supply supercharging air at the end of the intake stroke when natural intake ends.

In addition, a timing valve is provided in the natural intake passage, and this timing valve is opened later than the intake valve opening timing, thereby increasing the negative pressure at the beginning of intake when the timing valve opens, and correspondingly increasing the negative pressure at the end of the intake stroke. A so-called late-opening inertia effect technique has also been proposed, which increases the pressure of the intake air and increases the filling efficiency of the intake air.

(Problems to be Solved by the Invention) However, when a timing valve is installed in the intake passage as described above and the pressure fluctuations in the intake passage are used to improve the intake air filling efficiency, many problems occur. In a cylinder engine, if pressure changes in intake passages in other cylinders are used, it is possible to obtain even larger pressure fluctuation characteristics and improve intake air filling efficiency.

In view of the above-mentioned circumstances, the present invention provides an engine intake system which improves engine output by further increasing pressure fluctuations in the intake passage downstream of the timing valve by utilizing pressure fluctuations in the intake passages of other cylinders. The purpose is to provide the following.

(Means for Solving the Problems) The intake system of the present invention includes a communication passage that communicates between different cylinders between the intake passages downstream of the timing valve provided in the intake passage, and the passage length of the communication passage is set to a predetermined length. It is characterized by being set to a length that allows pressure waves to propagate in the operating interval between cylinders in the rotation range.

(Function) In the above-mentioned intake system, the intake passages downstream of the timing valve are communicated between different cylinders by a communication passage, and in a predetermined rotation range, pressure waves propagate through the communication passage at intervals of a between the cylinders. However, due to this pressure wave, the pressure fluctuation in the intake passage downstream of the timing valve is amplified and its fluctuation range becomes larger, and the negative pressure part becomes more negative pressure, and the positive pressure part becomes more positive pressure, for example. While increasing the negative pressure at the timing of opening the timing valve in partial supercharging or delayed opening inertia action, it is possible to improve the filling efficiency of intake air by increasing the pressure in the latter half of the intake stroke.

(Example) Hereinafter, each embodiment of the present invention will be described in detail along with the drawings.

Example 1 This example relates to a partially supercharged intake system for a two-cylinder rotary piston engine, and FIG. 1 shows the overall configuration, and FIG. 2 shows pressure fluctuation characteristics.

The engine 1 includes a first cylinder 1F and a second cylinder 1R.
In the case R1F and 1R, a rotor 3 is supported by an eccentric shaft 4 in a housing 2 so as to be capable of planetary rotation, and a working chamber 5 is formed between the rotor 3 and the housing 2. The housing 2 of each cylinder 1F and IR is provided with a main boat 6 and a supercharging boat 7, respectively, which open during the operation of the intake stroke.

The intake passage 8 that supplies intake air to the 6 air 1 m 1F and 1R of the engine 1 has an air cleaner 9 and an intake air amount sensor 10 at its upstream end, and branches into a first intake passage 11 and a second intake passage 12 midway. ing. The first intake passage 11 is for supplying intake air to the main boat 6 by natural intake, while the second intake passage 12 is for supplying supercharging air to the supercharging boat 7.

The first intake passage 11 is provided with a surge tank 14 at the downstream side of the first throttle valve 13, and the downstream side is connected to each cylinder.
F, branch passage 11a for IR;

It branches to 11b and is connected to the main boat 6.6 of each Qi@1F and IR.

On the other hand, the second intake passage 12 includes a supercharger 16 at a downstream side of the second throttle valve 15, and independent intake passages 12a and 12b for each cylinder 1F and 1R from the downstream side of the supercharger 16.
The downstream end of each is connected to the supercharging boat 7.7 of each cylinder IF and IR. The above independent intake passage 12
Surge tanks 17 and 17 are disposed midway between a and 12b, and a timing valve 18 is interposed and operated to open and close at a predetermined timing.

That is, a valve casing 19 is installed in an intermediate housing 2a of the engine 1, and the independent intake passages 12a, 12 are connected from the intermediate housing 2a to the valve casing 19.
A cylindrical timing valve 18 is rotatably fitted into the valve casing 19. The inside of the timing valve 18 is partitioned into the air 11F and IR by a central partition wall 18C, and the surge tanks 17 and 17 of the upstream independent intake passages 12a and 12b are connected to both ends thereof.

The peripheral wall of the timing valve 18 has openings 18a and i.
8b is provided, and when the openings 18a, 18b communicate with the independent intake passages 12a, 12b on the downstream side, the supercharger 1
It is configured to supply supercharging air from 6. Also, supercharged g! A relief valve 22 for regulating the upper limit of the boost pressure is disposed in the relief passage 21 that bypasses 416.

Further, a communication 123 is connected between the independent intake passages 12a and 12b for each cylinder IF and 'lR downstream of the timing valve 18 in the second intake passage 12. The length of this communication passage 23 is set to a length that allows pressure waves to propagate during the operating interval between the cylinders 1F and 1R in a predetermined rotation range (for example, a high rotation range). In addition, the communication path 2
3 is provided with a shutter valve 24 that closes the communication passage 23 in a range other than the predetermined rotation range (eg, low rotation speed iM).

The timing valve 18 is provided with a pulley 20 at the end of the shaft 18d, and is driven to rotate in synchronization with the rotation of the engine, that is, the rotation of the eccentric shaft 4, and the openings 18a and 18b are opened independently at a predetermined time (see FIG. 2). The intake passages 12a and 12b are opened and closed. Further, the second throttle valve 15 of the second intake passage 12 is connected to the first intake passage 11.
When the first throttle valve 13 reaches a predetermined opening degree, the first throttle valve 13 is linked by a link mechanism 25 to open, and the supercharger 16 is driven in response to the opening of the second throttle valve 15. This supercharger 16 is driven by engine output via a clutch means (not shown).

The opening and closing timings of the main port 6, supercharging port 7, and timing valve 18 in the first cylinder 1F and the second cylinder 1R are set as shown in FIG. 2, and the first cylinder 1F and the second cylinder 1R are in phase. are set at timings shifted by 180°. With respect to the opening/closing timing of the main boat 6 (dashed line), the supercharging boats 1-7 (dashed line) open at approximately the same timing and close later than the main boat 6. Furthermore, the timing valve 18 opens just before the main boat 6 closes and closes together with the supercharging boat 7.

The pressure change in the port corresponding to the opening/closing timing is such that in the main boat 6 (dashed line), the negative pressure increases when the main boat 6 is open, and the pressure increases when the main boat 6 is closed. Moreover, the supercharged boat 7 is
If there is no communication passage 23, as shown by the chain line, when the supercharging boat 7 opens, the timing valve 18 closes and supercharging is not performed, but there is residual supercharging pressure and the pressure is high, which is the main boat. When the timing valve 18 opens, the pressure increases due to the supply of supercharging air, and the pressure of the supercharging boats 7, ? 5 and the timing valve 18 are closed, the pressure becomes high.

When the pressure wave of the supercharging boat 7 of another cylinder is propagated through the communication passage 23, the pressure wave is propagated with a shift of 180@, that is, the operating interval between the cylinders IF and 1R, so the pressure changes are overlapped and amplified. As shown by the solid line, the pressure change in the supercharging boat 7 when the communication passage 23 is open is such that the negative pressure when the timing valve 18 opens is large;
It changes so that the positive pressure when closing becomes higher.

Due to the pressure change caused by the action of the communication passage 23, the positive pressure at the time when the timing valve 18 closes is high, and the supercharging pressure supplied to the working chamber 5 is increased, thereby improving the charging efficiency.
While the main boat 6 is open due to the large negative pressure when the timing valve 18 opens, the main boat 6
This aims to improve filling efficiency by promoting air intake from the tank and reducing blowback.

Example 2 This example is an example of an in-line six-cylinder reciprocating engine, and the third
The overall configuration is shown in the figure, and pressure changes are shown in Fig. 4.

The engine 30 includes first to sixth cylinders 01 to C6 each having an open intake boat 31 and an exhaust boat 32,
1st to 3rd cylinders C1 to C3 and 4th to 6th cylinders C4
-C6 are divided into cylinder group groups. Each cylinder C
The order of operation of cylinders 1 to C8 is set in the order of cylinders 1-5-3-6-2-4, and operations are performed at equal intervals in both cylinder groups.

The intake passage 33 includes an air cleaner 34 and an intake air amount sensor 35, and has two branch passages 33a and 3 corresponding to the cylinder groups.
It is branched into 3b. Each branch passage 33a, 33b has a throttle valve 36a, 36b, a surge tank 37a, 37
b. The intake passages are branched via the timing valve 39 into independent intake passages 418 to 41f for each cylinder C1 to C6.

The timing valve 39 is fitted into a valve casing 40, and upstream portions of the independent intake passages 41a to 41f are formed in the valve casing 40. The inside of the timing valve 39 is divided into sections for each cylinder group by a gap W39G in the center, and surge tanks 37a, 37 of branch passages 33a, 33b on the upstream side are provided at both ends thereof.
b is connected, openings 39a to 39f for each independent intake passage 41a to 41f are provided in the peripheral wall of the timing valve 39, and when the openings 39a to 39f communicate with each independent intake passage 41a to 41f, each cylinder C1 to It is configured to supply intake air to C6.

Furthermore, each cylinder Cs” downstream of the timing valve 39
The independent intake passages 41a to 41f for □Cs are connected to communication passages 42 and 43 that communicate with each other in each cylinder group. This communication passage 42.43 connects each cylinder Cs "C3, C4
~CG communicate with each other at a distance equal to phase U, and the length of the communication path 42.43 is the length that pressure waves propagate in the operating interval between cylinders in a predetermined rotation range (for example, high rotation range). is set to . In addition, the communication passage 42.43 is connected to a region other than the predetermined rotation range (for example, a low rotation range).
A shutter valve (not shown) is provided which closes at .

The timing valve 39 is provided with a pulley 44 at the end of the shaft 3911, and is driven to rotate from a crank pulley 45 via a belt 46 in synchronization with engine rotation, at a predetermined timing corresponding to the intake stroke of each cylinder C1 to C6. (4th
(see figure), the openings 398 to 39f are independent intake passages 418.
~41f opens and closes. In addition, branch passages 33a, 33
Both throttle valves 36a and 36b of b are linked by a link rocky structure 47 so as to open and close at the same opening degree.

The opening/closing timing of the intake valve (not shown) of the intake boat 31 and the opening/closing timing of the timing valve 39 are as follows.
The settings are as shown in FIG. This 4th figure is the 1st
The first to third air nCX communicated by the communication path 42 of
- Only C3 is shown, 4th to 6th cylinders C4 to C6
The same applies to the above, and illustration thereof is omitted. Intake boat 31
The timing valve 39 (solid line) opens later than the opening/closing timing shown in (broken B) and closes almost simultaneously.

The pressure change in the intake boat 31 corresponding to the above-mentioned opening/closing timing is such that when there is no communication passage 42, a large negative pressure is generated between the time the intake boat 31 opens and the timing valve 39 opens, as shown by the broken line. At the same time as the valve 39 opens, intake air flows in and the pressure rises, causing the intake boat 31
The highest pressure occurs near the point where it closes.

Then, the intake boats 31 of other cylinders are connected through the communication passage 42.
When the pressure waves propagate, the pressure waves propagate with a difference of the operating interval between the cylinders, so the pressure changes overlap and act to amplify, and the pressure waves of the intake boat 31 with the communication passage 42 open are As shown by the solid line, the pressure changes such that the negative pressure becomes larger when the three timing valves open, and the pressure becomes higher when they close.

Due to the pressure change caused by the action of the communication passage 42, the negative pressure when the timing valve 39 opens increases, the intake air flow rate at the start of inflow increases, and the pressure increases when the three timing valves close, pushing the intake air, The overall filling efficiency is improved.

Note that in this embodiment, the surge tanks 37a, 3
7b is provided upstream of the timing valve 39, and intake air is supplied from the axial direction of the timing valve 39 to utilize the supercharging effect due to the dynamic effect of the intake air between the surge tanks 37a and 37b in the timing valve 39. There is.

(Effects of the Invention) According to the present invention as described above, the intake passages downstream of the timing valve are communicated between different cylinders by a communication passage, and the passage length of the communication passage is set to the length of the passage between the cylinders in a predetermined rotation range. By setting the length so that pressure waves propagate at intervals of vJ, pressure fluctuations in the intake passage downstream of the timing valve are amplified by the pressure waves propagating through the communication passage in a predetermined rotation range, and the width of the fluctuation becomes large. For example, during partial supercharging or slow opening inertia action, the negative pressure part becomes more negative pressure, and the positive pressure part becomes more positive pressure, increasing the intake air filling efficiency and improving engine output. It is something that can be done.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of an engine intake system in J3 according to the first embodiment of the present invention, Fig. 2 is a characteristic diagram showing the opening/closing timing and pressure change characteristics in the first embodiment, and Fig. 3 is a diagram of the present invention. A schematic configuration diagram of an engine intake system according to a second embodiment of the invention. FIG. 4 is a characteristic diagram showing opening/closing timing and pressure change characteristics in the second embodiment. 1.30...Engine 1F, 1R, C1-C6...Cylinder 8.33...
...Intake passage

Claims (1)

[Claims] (1) In an engine equipped with a timing valve in the intake passage, a communication passage that communicates between different cylinders is provided between the intake passages downstream of the timing valve, and the length of the communication passage is set to allow operation between the cylinders in a predetermined rotation range. An engine intake device characterized by being set to a length that allows pressure waves to propagate at intervals.