JPS639638A - Air intake device of engine - Google Patents

Abstract

PURPOSE:To improve the lubrication performance of a gas sealed sliding contact face in a combustion chamber by opening a lubricating oil passage to a flow back passage, in a engine in which, under a low load, intake air in a combustion chamber under a compression stroke flows back to a combustion chamber of the other cylinder under an intake stroke through the flow pack passage. CONSTITUTION:A rotary type control valve 14, which opened fully under a low load is provided in a connecting passage 13 which is a flow back passage connecting together respective operation chambers 12f, 12r of 2 cylinders F, R of a 2-cylinder rotary engine. With this, it is made possible to allow the intake air in the operation chamber under a compression stroke to flow back to the operation chamber of the other cylinder under an intake stroke, under low load condition. In this case, an oil supply port 38 is opened to the connecting passage 13 for making it possible to lead-in the lubricating oil from a metering oil pump 30 to this oil supply port 38 through a switching valve 33 and lubricating oil passage 35. This switching valve 33 is controlled to be switched to the open side of the lubricating oil passage 35 by a lubricating oil control circuit 45 when the control valve 14 is detected to be in open condition by a opening sensor 44.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to an intake system for an engine.

[Prior art] In an Otto cycle engine, from the standpoint of reducing so-called pumping loss, a recirculation port that is independent of the intake port that communicates with the intake passage is opened into the combustion chamber of each cylinder, and each recirculation port is connected to multiple cylinders. An intake system has been proposed in which a reflux passage is provided that communicates with the entire reflux port, and each reflux port closes later than the closing timing of the intake port.
(See Japanese Patent Application Laid-Open No. 172429/1982).

This so-called late closing method of the recirculation port allows intake air from the combustion chamber to be recirculated into the combustion chambers of other cylinders in the intake stroke through the recirculation passage at the beginning of the compression stroke, especially when the engine is under low load. , there is an advantage that the pumping loss in the intake stroke can be reduced.

On the other hand, gas seal sliding surfaces are lubricated to improve the wear resistance of the gas seals in the combustion chamber and the airtightness of the combustion chamber. In order to provide uniform lubrication, a so-called mixed fuel supply system is known in which lubricating oil is mixed with fuel in an intake passage or a carburetor and then supplied into a combustion chamber.

However, in engines that employ the above-mentioned slow-closing method of the recirculation port, when the recirculation passage is open and the engine is at low load, especially at light loads, the air-fuel mixture is exchanged through the recirculation passage, and the intake passage is closed. Since the flow velocity of the passing intake air becomes very low, there is a problem in that the lubricating oil and fuel are not sufficiently mixed, resulting in a decrease in lubrication efficiency.

[Purpose of the Invention] The purpose of the present invention is to solve the above-mentioned problems in an engine that employs a slow closing method for the recirculation port, and to improve the lubrication efficiency of gas seal sliding surfaces by air-fuel mixture refueling. .

[Configuration of the Invention] Therefore, in the present invention, independent of the intake port,
Equipped with a reflux port that closes later than the intake port and a reflux passage that connects the reflux ports of multiple cylinders, during low load,
In an engine in which intake air in a combustion chamber during a compression stroke is recirculated through the recirculation passage into a combustion chamber during an intake stroke of another cylinder, a lubricating oil passage for lubricating the inside of the combustion chamber is opened in the recirculation passage. The present invention provides an engine intake device characterized by the following features.

Note that the "combustion chamber" as used in the present invention means a working chamber in a rotary piston engine.

[Effects of the Invention] According to the present invention, when the oil return passage is open during low load, the lubricating oil is injected into the air-fuel mixture flowing through the return passage at a high flow rate, so that the mixture of lubricating oil and fuel is reduced. This promotes uniform lubrication of the sliding surfaces of the gas seals in the combustion chamber, and improves lubrication efficiency. Furthermore, when the recirculation passage is in a closed state, the lubricating oil remaining around the control valve also has the effect of improving the sealing performance of the control valve.

[Example] Hereinafter, an example of the present invention will be specifically described with reference to the attached drawings regarding a two-cylinder low-repetition piston engine. However, the present invention is not limited thereto, and Of course, the present invention can also be applied to rotary piston engines, as well as reciprocating engines with two or more cylinders.

As shown schematically in Fig. 1, the two-cylinder rotary piston engine E has a front
Both sides 1f of the intermediate housing l, which is composed of two rear cylinders F and R, and separates these front and rear cylinders F and R.
, lr, the primary intake ports 2 (2r) are opened, and each side housing 3.4 forming each outer wall is opened.
Secondary intake ports 5f and 5r are opened on the inner surface 31°41 of the cylinder.

As is well known, the rotors 6f and 6r of each cylinder F and R perform a planetary rotational motion while sliding their top sides on the trochoid inner peripheral surfaces of the rotor housings 7f and 7r to perform suction and compression. , explosion, combustion.

Repeat each exhaust stroke continuously.

Each of the above primary intake ports: H, 2r represents each branch primary intake passage 8', 8r branched from the gathering part 8C of the primary intake passage 8.
, and upstream of the collecting portion 8C of the primary intake passage 8,
A primary throttle valve 9 that opens and closes in response to depression of the accelerator pedal 16 is provided. Further, each of the secondary intake ports 5f and 5r is connected to each branched secondary intake passage 10', 10r branched from the gathering part 10c of the secondary intake passage 10.
A secondary throttle valve is connected to the primary throttle valve 9 and is opened via a link mechanism 17 when the primary throttle valve 9 is opened beyond the set opening degree. A valve 11 is provided.

As shown in FIG. 1, the intermediate housing 1 has a reflux passage or a communication passage 13 (hereinafter simply a communication passage) that passes through the intermediate housing 1 in its thickness direction and communicates the working chambers 12f and 12r of the two front and rear cylinders F and R. A rotary control valve 14 for opening and closing the communication passage I3 is provided in the communication passage I3. The control valve 14 is fully opened by an actuator (not shown) when the throttle opening of the primary throttle valve 9 is lower than the set opening by the fuel control circuit 18 during low load, and on the other hand, when the throttle opening is larger than the set opening. It is designed to be fully opened.

As shown in FIG. 2 for the front cylinder F, the front opening 13f of the communication passage 13 is set on the leading side of the intake port 2f when viewed in the rotational direction of the rotor 6f.

In FIG. 1, when the control valve 14 is closed, the engine operates in the same manner as a normal rotary piston engine without the communication passage I3.

On the other hand, when the control valve 14 is open, the communication passage 13 acts as follows. That is, from the end of the intake stroke of the front side working chamber 12f to the front stage of the compression stroke, the rear side working chamber 12r is located at the front stage of the intake stroke due to the phase difference. Therefore, the pressure in the front working chamber +2f is higher than the pressure in the rear working chamber 12r. During this time, both the front side communication port 13f and the rear side communication port 13r are open, and since the communication passage 13 is in a communicating configuration, the intake air in the front side working chamber +2f flows into the rear side working chamber 12r. As a result, the pressure increase in the front working chamber 12f becomes smaller, and the pressure decrease in the rear working chamber 12r also becomes smaller. Therefore, the pumping loss is reduced. Thereafter, from the time when the rear side working chamber 12r reaches the end of the intake stroke to the front stage of the compression stroke, the front side working chamber 12f is located at the front stage of the intake stroke due to the phase difference. Therefore, the pressure in the rear working chamber 12r is higher than the pressure in the front working chamber 12r. During this time,
Rear side communication port 13r and front side communication port 13f
are both open and the communication passage 13 is in communication, so the intake air in the rear working chamber 12r flows into the front working chamber 12.
flows into f.

As a result, the pressure increase in the rear working chamber 12r becomes smaller, and the pressure decrease in the front working chamber 12f also becomes smaller. Therefore, the pumping loss is reduced. Thereafter, such an action is repeated between the front side working chamber 121' and the rear side working chamber 12r.

FIG. 3 shows a two-cylinder rotary piston engine system equipped with an intake device capable of supplying lubricating oil into the communication passage I3 according to the present invention. Lubrication of the sliding surface of the gas seal serves to improve the wear resistance of the seal as well as the airtightness of the gas seal. In this embodiment, in addition to the mixture oil supply method in which lubricating oil is mixed with intake air and supplied to the working chamber, a direct oil supply method is also used in which lubricating oil is directly supplied to the working chamber.

As shown in FIG. 3, the above system includes a metering oil pump 3o for discharging lubricating oil, and a switching valve 33 for switching the supply route of lubricating oil supplied with mixed air in response to the opening and closing of the control valve 14. , front and rear branch primary intake passages 8f and 8r to supply air-fuel mixture through the intake passage.
Refueling ports 3'N and 37r are open to the respective parts, refueling ports 38 are opened to the communication passage 13 for supplying air-fuel mixture through the communication passage 13, and front and rear oil supply ports are open for direct oil supply to the working chamber. Each working chamber 12f.

Direct oil supply ports 3 each open to 12r
6r, 36r, and multiple lubricating oil passages 31°31f,
31r, 32, 34.34 (34r, 35 are provided.

FIG. 4 is an enlarged plan sectional view of the vicinity of the control valve 14, and FIG.
The figure is a sectional view taken along the line A--A in FIG. 4. As shown in these figures, there is an inner opening 4 in the control valve 14 that opens radially inward in the circular skin cross section into the through hole 41 of the control valve 14.
0 and an outer opening 42 that opens radially outward and can be connected to the oil supply port 38.

In FIG. 3, the metering oil pump 3° is a pump that measures and supplies lubricating oil for lubricating the gas seal sliding surface according to the engine speed and load,
Generally, a plunger pump is used, and rotation is provided by an eccentric shaft (not shown), and the stroke is adjustable. Switching valve 33
The control valve 14 is controlled by the lubricating oil control circuit 45 (see FIG. 3) using the open/closed state of the control valve 14 detected by the control valve opening sensor 44 provided for the control valve 14 as input.
is in the open state, the lubricating oil passage 32 and the lubricating oil passage 35
It is a three-way valve that operates so that the lubricating oil passage 32 and the lubricating oil passage 34 are connected when the control valve I4 is in the open state.

A method of operating the lubricating oil supply nostem will be specifically explained.

In FIG. 3, a lubrication system for direct lubrication and a lubrication system for mixed lubrication are independently connected to the metering oil pump 30, and the lubricating oil discharged from the metering oil pump 30 is , the working chamber 12r is divided into the two systems mentioned above.

12r. Lubricating oil that is directly supplied is
The metering oil pump 30 passes through the lubricating oil passage 31 to the branch part 31c, and from there the front working chamber 12
The rear working chamber 12r is supplied with oil through the direct oil supply port 36f through the lubricating oil passage 31r.

On the other hand, when the control valve 14 is open at low load and the communication passage 13 is in the open state, the lubricating oil supplied with mixed air is controlled by the lubricating oil control circuit 45 to Since the lubricating oil passage 32 is connected to the lubricating oil passage 35 via the switching valve 33 and the lubricating oil passage 35 to the lubricating oil port 38, the oil supply in the control valve 14 shown in FIG. The mixture is discharged through the hole 39 from the inner opening 40 into the air-fuel mixture passing through the through hole 41 . Conversely, when the control valve 14 is closed and the communication passage 13 is in the closed state, the switching valve 33 is set by the lubricating oil control circuit 45 so that the lubricating oil passage 32 and the lubricating oil passage 34 are connected, and the lubricating oil is lubricated. The oil passage 32 passes through the switching valve 33 and the lubricating oil passage 34 to reach the branching part 34c, and from there the lubricating oil passage 34 goes to the front side primary intake passage 8f.
It is discharged into the intake air passing through the intake passage 8r from the oil supply port 37f through the lubricating oil passage 34r, and the intake air passing through the primary intake passage 8r from the oil supply port 37r through the lubricating oil passage 34r. is discharged.

When the engine is under low load and the control valve 14 is opened to open the communication passage 13, the flow velocity of the intake air passing through the front and rear branched primary intake passages 8f and 8r becomes extremely small. Therefore, even if lubricating oil is discharged into such intake air, the lubricating oil and fuel will not be sufficiently mixed, and effective air-fuel mixture supply will not be performed. However, at this time, as the engine cycle progresses, the air-fuel mixture passes through the communication passage 13 at a high flow rate due to pressure from the working chamber during the compression stroke to the working chamber during the intake stroke of the other cylinder. Therefore, in the present invention, when the communication path 13 is in the open state, the lubricating oil is discharged into the reflux with such a high flow rate, so that the lubricating oil and fuel are sufficiently mixed and the gas seal sliding surface The lubrication efficiency is improved.

On the other hand, when the engine load increases and the control valve I4 is closed and the communication passage 13 is closed, the flow velocity of the intake air passing through the front and rear branch primary intake passages 8f and 8r becomes sufficiently large. Lubricating oil is discharged during such intake.

Furthermore, when the control valve 14 is closed, the communication path 13 must be completely shut off. By the way, in the present invention,
As shown in FIGS. 4 and 5, when the control valve 14 is open, a portion of the lubricating oil discharged into the communication passage 13 is
The lubricating oil enters the gap 43 of the rotating sliding surface of the control valve 14, and remains there even when the control valve 14 is closed. This remaining lubricating oil has the effect of sealing the control valve 14 when the valve is closed, completely blocking the communication path 13 mentioned above.

As explained above, the present invention improves the lubrication efficiency of the gas seal sliding surface when the control valve 14 is open when the engine is under low load, and also improves the sealing performance when the control valve 14 is closed. It is.

[Brief explanation of the drawing]

FIG. 1 is a sectional explanatory diagram of a rotary piston engine according to an embodiment of the present invention, FIG. 2 is a side sectional explanatory diagram of the rotary piston engine, and FIG. 3 is a rotary piston engine equipped with an intake device according to the present invention. FIG. 4 is a partial plane cross-sectional view of the rotary piston engine showing the connection status of the control valve, communication hole, and lubricating oil passage; FIG. 5 is a cross-sectional view taken along the line A-A in FIG. 4. . F, R...Front side 1 Rear side cylinder, 8...Primary intake passage, 9...Throttle valve, IO...2
Sub-intake passage, 13... Communication passage, 14... Control valve, 18... Actuator, 30... Metering oil pump, 33... Switching valve. Patent applicant: Mazda Motor Corporation representative Patent attorney: Mr. Hajime and 2 others

Claims (1)

[Claims] (1) Equipped with a reflux port that is independent of the intake port and closes later than the intake port, and a reflux passage that communicates the reflux ports of multiple cylinders, and at low load, the intake air in the combustion chamber during the compression stroke is refluxed. An intake system for an engine in which a lubricating oil passage for lubricating the inside of the combustion chamber is opened in the recirculation passage, in an engine configured to recirculate air into a combustion chamber during an intake stroke of another cylinder through a passage. .