JPS6390622A - Suction system for rotary engine - Google Patents

Abstract

PURPOSE:To keep off any backflow of suction air as well as to improve the extent of charging efficiency, by directing an opening to an operating chamber of an interconnecting part to the direction leading side of a rotor, in case of a device which interconnects an interval between adjacent cylinders and controls a pumping loss. CONSTITUTION:In case of a 2-cylinder engine having cylinders F and R with an operating chamber where each of rotors 2f and 2r are housed free of rota tion, auxiliary suction passages 22f and 22r to be interconnected to each operat ing chamber are formed in an intermediate housing 4 partitioning off these operating chambers of respective cylinders F and R. Both auxiliary passages 22f and 22r are interconnected to each other by the interconnecting hole 31 installed so as to interconnect the operating chamber of the cylinder on one side in a suction stroke and that of the cylinder on the other in a compression stroke, and a butterfly type control valve 32 is installed in this interconnecting hole 31. And, an opening to each operating chamber of auxiliary suction ports 7f and 7r to be connectedly installed in these respective auxiliary passages 22f and 22r is made so as to be formed as tilted to the direction leading side of these rotors 2f and 2r.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an intake device for a low engine engine.

``Prior art'' In an automatic cycle engine in which engine load is controlled by a throttle valve, the intake air amount is normally throttled by the throttle valve and the intake stroke is operated with the intake pressure lower than atmospheric pressure, which reduces resistance loss. A kind of so-called pumping loss occurs.
At low loads, the intake pressure is low (e.g. -0, 7kg/ax' gauge), and the resulting pumping loss is about the sum of various resistance losses. It is estimated that it accounts for 30% of the total. Therefore, if this pumping loss can be reduced, the fuel efficiency of the engine can be significantly improved.

Conventionally, as a method to reduce this pumping loss, a communication boat is provided that is independent of the main intake boat and closes later than the main intake boat, and a communication passage is provided to communicate between the communication boats of multiple cylinders. At low loads, a portion of the intake air from the cylinder at the beginning of the compression stroke flows into other cylinders at the front stage of the intake stroke through the communication passage.
A late closing system using so-called inter-cylinder communication has been proposed, which suppresses the negative pressure of intake air and reduces pumping loss (see, for example, Japanese Patent Laid-Open No. 172429/1983).

However, in a low-return engine equipped with a pumping loss control means of a late-closing type using communication between cylinders, when the pumping loss control means is activated, a portion of the intake air flowing into the working chamber via the communication passage becomes fuel. This causes a backflow from the main intake boat, reducing filling efficiency and
There were problems such as variations in the amount of fuel supplied and unstable combustibility.

In addition, at low loads when the pumping loss control means is activated, the air-fuel ratio of the air-fuel mixture is increased (becomes leaner), thereby increasing fuel efficiency and reducing hydrocarbons (hereinafter referred to as
It's called HC. ), but increasing the air-fuel ratio at such low loads will worsen ignition performance, so
This posed the problem of having to supply more fuel than necessary, resulting in a decrease in fuel efficiency and exhaust gas cleanliness.

[Object of the Invention] The present invention provides a low-pressure engine equipped with a pumping loss control means through communication between cylinders, which prevents intake air from flowing backward from the main intake boat when the pumping loss control means is activated, thereby increasing charging efficiency. The purpose of the present invention is to provide an intake system that stabilizes combustibility, allows operation at an appropriate air-fuel ratio at low loads without deteriorating ignitability, and thereby improves fuel efficiency and cleanliness of exhaust gas. do.

[Structure of the Invention] In order to achieve the above object, the present invention provides a rotary engine equipped with means for controlling pumping loss through communication between cylinders, in which the opening of the communication section to the working chamber is oriented toward the leading side in the rotational direction of the rotor. To provide an intake device for a low-rise engine, which is characterized by:

[Effects of the Invention] According to the present invention, the opening of the communication portion to the working chamber is oriented toward the leading side, while the main intake boat is located on the trailing side of the opening, so that the operation is performed through the communication path. All intake air flowing into the chamber flows in the direction of rotation of the rotor and does not flow into the main intake boat, so there is no backflow of intake air from the main intake boat, thus increasing filling efficiency and fuel supply. No amount variation occurs, thus improving fuel efficiency and combustibility.

In addition, the intake air supplied to the working chamber via the communication passage flows in the rotor rotational direction along the trochoid inner circumferential surface of the rotor housing, so the fuel is forced into the leading side, and as a result, around the spark plug. A locally rich air-fuel mixture is formed, so-called stratified air supply, and even if the air-fuel mixture in the working chamber is lean overall, the rich air-fuel mixture around the spark plug completely ignites the engine. , it is possible to operate with a lean air-fuel mixture according to the low load range, improving fuel efficiency and exhaust gas cleanliness.

[Example] Hereinafter, the first embodiment of the present invention will be described for a two-cylinder rotary engine.
An example will be explained.

Figure 1 does not show a system configuration diagram of a two-cylinder rotary engine. Regarding members that are common to the front and rear sides, only the front side (O) is shown in the figure, and the rear side members are not shown, but in the text, they are indicated by the suffix f.

The suffix r is added to distinguish between corresponding front and rear side members.

In a rotary engine RE, the rotors 2f and 2r perform planetary rotational motion around the eccentric shaft 3 in the casings 1f and 1r to perform suction, compression, explosion, expansion, and exhaust. The intermediate housing 4 is composed of front and rear cylinders F and R that repeat continuously, and the front and rear side surfaces of the intermediate housing 4, which form partition walls between the front and rear cylinders F and R, are provided with, respectively, The front and rear main intake boats 6f and 6r open, and these main intake boats 6f.

Rotor 2f from 6r, slightly on the leading side when viewed from the direction of rotation of 2r is the working chamber 5f, which is only used during high loads.

Front and rear auxiliary intake boats 7f and 7r are provided with their openings facing the leading side to supply intake air to the engine 5r. In addition, the rotor housing 8f forming the peripheral wall of each of the front and rear cylinders F and R,
On the side of 8r, there are front and rear holes for discharging the combustion gas in the working chambers 5f and 5r to the front and rear branch exhaust passages 9r and 9r, respectively, after ignition and combustion with the spark plugs 10f and 10r. Exhaust boats Ilf and llr are open.

And both the front 5 and rear working chambers 5r.

A common intake passage 12 is provided in order to supply intake air to the 5r, and in this common intake passage 12, from the upstream side, an air cleaner 13, an air flow meter 14 that detects the amount of intake air from moment to moment, and the depression of an accelerator pedal (not shown) are installed. A throttle valve 15 is provided which is opened and closed depending on the timing.

Common intake passage above! Reference numeral 2 denotes a branch portion 16 slightly downstream of the throttle valve 15, and a front side branch intake passage 1 that communicates with the front side main intake boat 6f and the auxiliary intake boat 7f.
7f, and a rear side branch intake passage 17r that communicates with the rear main intake boat 6r and the auxiliary intake boat 7r.

At a position downstream of the branch portion 16, the front.

Rear branch intake passages 17 (17r include front and rear injectors 18r for injecting fuel during intake)
, 18r are interposed with their injection ports inclined in the downstream direction.

Furthermore, front and rear branch intake passages 17f, 17
r is a front that communicates with the main intake boats 6f and 6r at second branch portions 19f and 19r, respectively, so that intake air is always passed regardless of the magnitude of the load.

Rear main intake passages 21f and 21r and auxiliary intake boat 7
Front and rear auxiliary intake passages 22r and 22r communicate with air intake passages 22r and 7r, and allow intake air to pass only during high loads.
It is branched into.

These front and rear auxiliary intake passages 22f, 22
Shutter valves 23f and 23r are interposed in r, respectively, and are opened only when the load is high. Each of these shutter valves 23f and 23r is driven by introducing positive pressure into the pressure chamber through a positive pressure introduction passage 24 communicating with the front branch exhaust passage 9f.
A first actuator 25 consisting of a positive pressure responsive diaphragm device is provided, and when the exhaust pressure in the front side branch exhaust passage 9f rises above a set value during high load, the actuator 25 is actuated by the positive pressure, and the link mechanism 26 The shutter valves 23f and 23r are opened via the shutter valves 23f and 23r.

By the way, in order to control pumping loss through communication between cylinders, the front and rear auxiliary intake boats 7f,
At a position slightly upstream of 7r, a communication hole 31 (see FIG. 3) is provided to communicate the front auxiliary intake passage 22f and the rear auxiliary intake passage 22r, passing through the intermediate housing 4 in the thickness direction. A butterfly type control valve 32 is provided to open and close the communication hole 31. In order to drive this control valve 32, a second actuator 33 consisting of a negative pressure responsive diaphragm device is provided, and in order to introduce negative pressure downstream of the throttle valve 15 into this second actuator 33, A negative pressure introduction passage 34 is provided that communicates the pressure chamber and the branch portion 16. This negative pressure introduction passage 34 has a branch part 1.
6 side toward the second actuator 33 side, in order:
When the negative pressure in the branch part 16 becomes weak, the pressure in the second actuator 33 is reduced by a signal from a control circuit 36 consisting of a check valve 35 for maintaining the negative pressure in the pressure chamber of the second actuator 34 and a microcomputer. A three-way solenoid valve 37 is provided for switching between negative pressure and atmospheric pressure introduced into the chamber. This three-way solenoid valve 37 is connected to an atmosphere introduction passage 38 whose other end is connected to the air cleaner 13 for introducing the atmosphere into the pressure chamber of the second actuator 33.

As shown in FIG. 2, the control valve 32 completely closes the communication hole 31 when the valve is opened, and at this time, the front and rear mountain cylinders F and R do not communicate with each other. ing.

On the other hand, as shown in FIG. 3, when the control valve 32 is opened, the communication hole 31 is opened to communicate the front and rear mountain cylinders F and R, and the front and rear auxiliary intake passages 22r are connected to each other.
, 22r are simultaneously blocked.

In the prior art, when the control valve 32 is opened, both the front and rear auxiliary intake passages 22f and 22r are not closed at the same time, so when pumping loss control is performed by communication between cylinders, , the air-fuel mixture flows through both the front and rear auxiliary intake passages 22f.

The fuel in the air-fuel mixture may enter the space between the upstream of the control valve 32 at 22r and the closed shutter valves 23f and 23r (see Figure 1), and the fuel in the air-fuel mixture may adhere to the wall, resulting in reduced air/fuel efficiency. There were problems in that variations occurred or atomization of the fuel was hindered. In this embodiment, the control valve 32
Since both the front and rear auxiliary intake passages 22r, 22r are closed off, no dead space is created.

Furthermore, as shown in FIG. 3, the openings of the front and rear auxiliary intake ports 7f and 7r to the working chambers 5f and 5r are inclined toward the leading side in the rotational direction of the rotors 2f and 2r. The fuel is forced into the leading side, and as a result, a stratified air supply is performed in which a rich mixture is locally formed around the spark plugs 10f and lor, and the mixture in the working chambers 5f and 5r as a whole is Even if the engine is lean, ignition is achieved completely by the rich air-fuel mixture around the spark plug 10 (10r).

The control circuit 36 (see FIG. 1) controls the intake air ff1Qa detected by the air flow meter 14 and the throttle opening TV detected by the throttle valve opening sensor 39.
θ, engine rotation speed N1 detected by a rotation speed sensor (not shown), and cooling water temperature Tw detected by a temperature sensor (not shown) as input information to perform pumping loss control and fuel control. .

The pumping loss control method by the control circuit 36 will be explained below.

As shown in FIG. 5, if the engine operating range is expressed using the engine speed N and the throttle opening TVθ as parameters, in this embodiment, the control valve 32 is opened in the range I, which corresponds to the low-medium load range. Pumping loss control is performed. Then, in the region including the high load range, high rotation range, and light load range, in order to increase charging efficiency in the high load range and ensure high output, the fuel shift etc. are prevented in the high rotation range. In order to prevent deterioration of ignitability in a light load range, the control valve 32 is closed and pumping loss control is stopped.

The control circuit 36 scans the control routine at a timing synchronized with the rotation of the eccentric shaft 3, reads the engine rotation speed N and the throttle opening TVθ in every scan, and determines whether the operating state of the engine RE is in the area shown in FIG. It is determined whether it corresponds to area I or area H.

As a result of the above determination, the operating state of engine r (E is in region r
If so, the control circuit 36 applies an on signal to the three-way solenoid valve 37 (see FIG. 1) in order to perform pumping loss control. When an on signal is applied to the three-way solenoid valve 37, the atmosphere introduction passage 38 is closed and the negative pressure introduction passage 34 is opened, and the pressure chamber of the actuator 33 and the branch part 16 are connected via the negative pressure introduction passage 34. communicates, negative pressure is introduced into the pressure chamber of the actuator 33, and as a result, the control valve 32 is opened via the link mechanism 4I (
The cylinders communicate with each other.

On the other hand, if the operating state of the engine RE corresponds to region H in FIG. 5, the control circuit 36 applies an off signal to the three-way solenoid valve 37 in order to stop pumping loss control. When an off signal is applied to the three-way solenoid valve 37, the negative pressure introduction passage 34 is shut off, and on the other hand, the atmosphere is introduced into the pressure chamber of the actuator 33 via the atmosphere introduction passage 38, and as a result, the link mechanism 4I via control valve 32
is closed (communication between the cylinders is cut off).

Next, the opening/closing timing of the front and rear auxiliary intake ports "H, 7r" and the flow of intake air when the control valve 32 is opened by the control circuit 36 and pumping loss control is performed will be described.

As shown in Figure 4, the front side auxiliary intake bow) -7f
begins to open at an eccentric shaft angle of 10° (hereinafter referred to only as an angle) a little later than the top dead center TDC of the first working chamber of the front cylinder F, as shown by the broken line G1, and closes at 360°. It has become. On the other hand, since the rear opening nR is 180° behind the front cylinder F, the rear auxiliary intake port 7r is connected to the broken line G2.
Top dead center TDCI' of the first working chamber of the rear cylinder R
It begins to open slightly later at 220 degrees and closes at 540 degrees. Therefore, from 2200 degrees to 360 degrees, where the opening timing of the front side auxiliary intake boat 7f and the opening timing of the rear side auxiliary intake boat 7r overlap, both the front and rear cylinders F and R
are designed to communicate with each other.

On the other hand, the front side intake pressure becomes like the curve CI, whereas the rear side intake pressure becomes like the curve C8. Therefore, as mentioned above, during the timing from 220° to 360° when the opening timings of the front and rear auxiliary intake ports 'N and 7r overlap, the intake pressure of the front cylinder F is equal to the intake pressure of the rear cylinder R. In the period surrounded by circles M, , M2 where the height is substantially higher, intake air flows from the front cylinder F to the rear cylinder R, the negative pressure in the rear cylinder R is suppressed, and the pumping loss is reduced. It looks like this.

Similarly, from 400° to 540°, the front
The opening timings of both rear auxiliary intake boats overlap, resulting in circle M3. In the period surrounded by M4, the intake pressure of the rear cylinder R is substantially higher than the intake pressure of the front cylinder F.
Intake air flows into the front cylinder F, and the negative pressure in the front cylinder F is suppressed.
Pumping losses are reduced. below,
This type of intake exchange is repeated between the front and rear cylinders.

As described above, according to the first embodiment of the present invention, the pumping loss is reduced by controlling the pumping loss, and since the opening of the communication portion to the working chamber is oriented toward the leading side, the stratified supply air is As a result, ignition performance is good even at high air-fuel ratios, improving fuel efficiency and reducing H in exhaust gas.
C can be reduced, and backflow of the air-fuel mixture to the main intake boat is prevented, so combustibility is improved.

Next, a second preferred embodiment of the present invention will be described regarding the two-cylinder rotary engine RE2, but a description of parts common to the first embodiment will be omitted. As shown in FIG. 6, in the second embodiment, the front and rear communication boats 50f and 50r are located on the leading side of the front and rear main intake boats 51f and 51r, respectively, on the upper wall surfaces of the rotor housings 52f and 52r. , rotor 53
It opens toward the leading side in the rotational direction of f and 53r. And both front and rear communication ports 50
A communication path 54 is provided that communicates f and 50r.

As shown in FIG. 7, in the vicinity of both the front and rear communication boats of the communication passage 54, fronts are provided for communicating or blocking the communication passage 54, respectively.

Rear side control valves 55f and 55r are provided.

These control valves 55r, 55r are opened by a drive means (not shown) such as an actuator when pumping loss control is performed in a predetermined operating range, and are closed when pumping loss control is to be stopped. It has become.

Only one control valve for opening and closing the communication passage 54 may be provided approximately in the middle of the communication passage 54, but if it is configured as in this embodiment, when the pumping loss control is stopped, Since the communication passage 54 can be prevented from becoming a dead space, the compression pressure can be increased, or the accumulation of fuel in the communication passage 54 can be prevented, so that combustibility can be stabilized.

Further, in order to effectively perform stratified air supply, a direct injection method in which fuel is directly injected into the working chamber is suitable, but this poses the problem of worsening atomization of the fuel.

Therefore, in order to effectively perform stratified air supply and promote atomization of fuel, an injector 56 for injecting fuel is interposed at a substantially intermediate position of the communication passage 54.

As mentioned above, both the front and rear communication boats 50 (5
0r is opened toward the leading side in the rotational direction of the rotors 53f and 53r, so when pumping loss control is performed in a predetermined operating range, the communication path 54
Through the front desk.

The intake air flowing in from the rear working chambers 57f and 57r flows in a layered manner along the tocoroid inner peripheral surfaces of the rotor housings 52r and 52r, respectively, and the fuel injected from the injector 56 into the communication passage 54 flows into the communication passage 54. The air is sufficiently atomized in the passage 54 and stratified by the air flow along the inner circumferential surface of the tocolloid, so that stratified air supply is performed in the same manner as in the first embodiment.

In the second embodiment, only one injector is provided in the middle position of the communication path 54, but the control valve 5! is provided in the vicinity of both the front and rear communication boats 510.50r.
Two injectors, a front injector and a rear injector, may be provided upstream (center side of the communication path 54) or downstream (communication port side) of M, 55r, respectively.

Further, only one control valve is provided at the center position of the communication path 54,
In the communication passage 54 near both the front and rear communication boats,
It is also possible to provide two injectors, one for the front and one for the rear.
Also preferred.

In addition, in this second embodiment or an embodiment with a preferable variation as mentioned above, when the control valve is closed and pumping loss control is stopped, if the control valve is provided downstream of the injector, Naturally, the injector should be stopped, but if a control valve is provided upstream of the injector, the above injector may be used as a main injector or sub-injector after taking measures against atomization such as air bleed. .

As described above, according to the second embodiment of the present invention as well, stratified air supply is performed, fuel efficiency is improved, and I
(C can be reduced.

FIG. 8 shows a third embodiment of the present invention regarding a two-cylinder rotary engine equipped with a mechanical supercharger.

The third embodiment has almost the same structure and operation as the first embodiment shown in FIG. 1, except for the provision of a mechanical supercharger and its auxiliary equipment. Components that are purchased and have the same functions are given the same numbers, and their explanations are omitted to avoid duplication.

Hereinafter, only the points different from the first embodiment will be explained.

In the third embodiment, the front and rear working chambers 5r
, 5r, a supercharging air passage 101 connected to the common intake passage 12 at a position downstream of the air flow meter 14 and upstream of the throttle valve 15 is provided. A vane-type or roots-type mechanical supercharger 103, which is mechanically driven by an eccentric shaft 3 via a belt +02, is interposed in this supercharging air passage lOI. In order to stably supply supercharging air, a pressurized air tank 1 is provided downstream of the mechanical supercharger 103 in the supercharging air passage +01.
04 is interposed, and a relief passage 105 is provided which extends upstream from the pressurized air tank 104, bypasses the mechanical supercharger 103, and communicates with the supercharging air passage lOI upstream of the mechanical supercharger +03. There is. A relief valve 106 is interposed in the relief passage 105, which is opened when the pressure in the pressurized air tank 104 exceeds a set value to maintain the supercharging pressure below the set value.

The supercharging air passage above! 01 pressurized air tank 104, an auxiliary intake passage 22f is connected to both the front and rear working chambers 5f, 5r at a predetermined timing in the latter stages of the respective intake strokes.
, 22r, and a rotary timing valve +07 that rotates in synchronization with the eccentric shaft 3 is provided.

Then, this timing valve 107, the front,
In the front and rear auxiliary intake passages 22f and 22r that communicate with the rear auxiliary intake boats 7f and 7r, the throttle valve 15 is opened to a predetermined degree or more, and the operating state of the engine is in the supercharging zone shown in FIG. The front and rear second throttles are opened and closed in conjunction with the throttle valve 15 when
``, I 08r is interposed.

In the third embodiment, when the control valve 32 is opened and both the front and rear cylinders F and R are in communication with each other, the control valve 32 simultaneously opens both the front and rear auxiliary intake passages 22 (22r). It can be closed,
Prevents the auxiliary intake passages 22' and 22r from becoming dead spaces.
However, in the case where both the front and rear auxiliary intake passages 22r, 22r cannot be closed by the control valve 32 due to construction requirements, etc., in the third embodiment, the second throttle valves 108f, 108r Auxiliary intake passage 22r
, 22r are closed, the auxiliary intake passages 22f, 2
It is possible to prevent 2r from becoming a dead space as much as possible.

As described above, in the third embodiment of the present invention, as in the case of the first embodiment, stratified air supply is performed and backflow of intake air to the main intake boat can be prevented, thereby improving fuel efficiency and improving combustibility. It is possible to improve the fuel efficiency and reduce HC in the exhaust gas.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of a two-cylinder rotary engine showing a first embodiment of the present invention. Figure 2 shows the front of the rotary engine shown in Figure 1.
FIG. 3 is a plan sectional view of both rear cylinders at the auxiliary intake boat position. FIG. 3 is an enlarged plan sectional view of the area around the control valve in FIG. 2. FIG. 4 is a diagram showing the intake pressure of both the front and rear cylinders of the rotary engine in the first embodiment and the opening area of the auxiliary intake boat with respect to the eccentric shaft angle. FIG. 5 is a diagram showing the operating range in which the pumping loss control of the rotary engine in the first embodiment should be performed, using engine speed and throttle opening as parameters. FIG. 6 and FIG. 7 are an elevational sectional view and a side sectional view, respectively, of a two-cylinder low engine engine showing a second embodiment of the present invention. FIG. 8 is a system configuration diagram of a two-cylinder rotary engine in which partial supercharging is performed by a Ja Makoto type supercharger, showing a third embodiment of the present invention. FIG. 9 is a diagram illustrating the operating range in which supercharging of the low-return engine should be performed and the range in which pumping loss control should be performed in the third embodiment, using engine speed and throttle opening as parameters. RE...Lower engine, 15...Throttle valve, 'N, 7r...Auxiliary intake boat, 31...Communication hole, 32...Control valve, 36...Control circuit,
RE2... Rokuri engine, 50f, 50r... Communication boat, 54... Communication path, 55F, 55r... Control valve, 56...
Injector, RE3... Rotary engine, 103... Mechanical supercharger, 107... Timing valve.

Claims (1)

[Claims] (1) An intake device for a rotary engine, which is equipped with means for controlling pumping loss through communication between cylinders, characterized in that the opening of the communication portion to the working chamber is oriented toward the leading side in the rotational direction of the rotor.