JPS62162733A - Air intake device for rotary piston engine - Google Patents

Abstract

PURPOSE:To avoid abnormal conditions of an engine, by providing a control valve for opening and closing a communication passage for communicating among cylinders and control means for opening the control valve when the engine is in abnormal conditions. CONSTITUTION:A primary throttle valve 9 is opened and closed by an accelerator pedal 16 and a secondary throttle valve 11 is actuated in association with the primary throttle valve 9 through a link mechanism 17. A control valve 14 in a communication hole 13 is provided with an actuator 18. There is provided a control circuit 20 for opening and closing the control valve 14 by controlling operation of the actuator 18. When abnormal conditions of an engine such as abnormal supercharge pressure 22, overheat 23, excessive rotation 24, knocking 25 and the like are detected, the control circuit 20 opens the control valve 14. With such an arrangement, output of the engine is greatly reduced and the abnormal conditions of the engine is avoided.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an air intake system for a rotary piston engine in which a rotor makes planetary rotational motion within a casing while sliding one side of each trochoid on the inner circumferential surface of the trochoid. It is related to the device.

[Sub-61 Technique] It is well known that so-called bombing loss occurs in an automatic cycle engine because the engine is normally operated by restricting the amount of intake air and lowering the pressure at the initial stage of compression below atmospheric pressure. . It is estimated that this bombing loss accounts for about 30% of the total of various resistance losses, and in this sense, if the bombing loss can be significantly reduced, the thermal efficiency of the engine can be significantly improved.

As methods for reducing this pumping loss, methods have been proposed in the past, such as changing the closing timing of the intake valve to avoid closing it early or late, and methods that recirculate a portion of the intake air to the intake system. .

As an intake system for a rotary piston engine that adopts the latter method, Japanese Patent Application Laid-Open No. 58172429 discloses a communication path that communicates the working chambers of two cylinders at a predetermined timing, and an engine load in the middle of this communication path. It has been proposed that a control valve is provided to limit the amount of ventilation in the communication path depending on the size.

Therefore, in a rotary piston engine equipped with the above-mentioned intake structure, during high-load operation where high output is required, it is necessary to close the communication passage and operate at a high compression ratio to guarantee high output. .

Under such poor engine operating conditions that require high output, so-called engine failures such as engine overspeed, an abnormal increase in boost pressure in supercharged engines, and engine overheating may occur. There's room. In the past, individual countermeasures were taken, such as cutting off fuel in response to engine overspeed, and opening a relief valve to temporarily relieve boost pressure in response to an abnormal increase in boost pressure. ing.

However, with conventional individual countermeasures, for example, when a fuel cut is performed, the engine speed temporarily drops, and when fuel is restarted due to this drop, the engine speed becomes overspeed again, requiring a fuel cut. A so-called surging phenomenon, such as a surging phenomenon, is likely to occur, and drivability may be significantly impaired.

[Object of the Invention] An object of the present invention is to provide an intake system for a low-repetition piston engine that can cope with the effects of various engine abnormalities.

[Structure of the Invention] For this reason, the present invention provides a low-flow cylinder in which the cylinders are communicated with each other by a communication passage that is closed after receiving the main intake port, and the intake air is circulated between the cylinders according to the phase difference between the cylinders. In a piston engine, a control valve is provided to open and close the communication passage, and a control means is also provided to open the control valve when an abnormality occurs in the engine.By opening the communication passage in response to various engine abnormalities, the engine output is reduced. This is a configuration that allows you to do so.

[Effects of the Invention] According to the present invention, the bombing loss reduction system is
By using the engine, it is possible to effectively deal with various engine abnormalities such as engine overspeed, overheating, and even abnormal boost pressure.

[Example] Hereinafter, an example of the present invention will be specifically described with reference to the accompanying drawings.

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, primary intake ports 2r, 2r are opened, while inner surfaces 3i, 4i of each side housing 3, 4 forming each outer wall have secondary intake ports 5r, 5r opened. .

As is well known, the rotors 6C and 6r of each cylinder P and T''t have their respective top sides connected to the rotor housings 7f and 7.
While in sliding contact with the inner circumferential surface of the trochoid of r, it performs planetary rotational motion, causing suction, compression, explosion, and combustion.

Repeat each exhaust stroke continuously.

The primary intake ports 2f and 2r are branched primary intake passages 8r that are branched downstream of the primary intake passage 8.

8r, and a primary throttle 7F9 is provided upstream of the primary intake passage 8 and is opened and closed depending on the engine load.

In addition, the above-mentioned secondary intake passages 5f and 5r are branched secondary intake passages 10r and I branched downstream of the secondary intake passage 10.
A secondary throttle valve 11 is interposed upstream of the secondary intake passage 10 and communicated with the secondary intake passage 10. The secondary throttle valve 11 is opened in conjunction with the opening of the primary throttle valve 9 when it is opened beyond a set opening degree.

And the primary and secondary intake passages 8. A supercharger 30 such as an exhaust turbocharger is provided upstream of 1O, and constitutes a supercharged engine that pressurizes and supplies intake air.

As shown in FIG. 2, the intermediate housing 1 is provided with a communication hole 13 that penetrates in its thickness direction and communicates the working chambers 12r, 12r of the two front and rear cylinders F and R. A control valve 1.1 is installed to open and close the control valve.

As shown in FIG. 2 for the front cylinder F, the communication hole 13 has a front opening 13r located at 1
Next or secondary intake port 2f, 5r to rotor 6f
is set on the leading side when viewed from the direction of rotation, and the imaginary line O
The opening edge is set so that it begins to open at the rotor phase shown by and finally closes at the rotor phase shown by the imaginary line C.

The function of this communication hole 13 will be explained in more detail using the time chart shown in FIG.

First, when the front rotor 6r passes the intake top dead center TDC, the front primary (secondary) intake port 2r (51') begins to open with a slight timing delay (for example, ATDC 32° in crank angle). Front side primary (secondary)
The front side opening 13f of the communication hole I3 begins to open (second
(See Figure O).

On the other hand, the rear side primary (secondary) intake port 2r (5r) is the front side primary (secondary) intake port 21'(51'
) and the front opening 131' of the communication hole 13 are still open at the timing when they are opened, and are closed some time after the front opening 13f is opened. In addition, the rear side opening 13r of the communication hole 13 is connected to the rear side primary (secondary)
Next) Since the intake port 2r (5r) is closed with a predetermined timing delay from the closing timing, during the time τ1 until the intake port 2r (5r) is closed, the communication hole 13 is closed to the front and rear intake working chambers! 2r and I2r.

During this communication time of 1, the intake working chamber 12r of the rear cylinder R is at the stage of transition from the end of the intake stroke to the beginning of the compression stroke, and the intake working chamber 12r of the front cylinder F, which is in the first half of the intake stroke, is As shown by arrow A, the intake air passes through the communication hole 13 and enters the rear intake working chamber 1.
2r to the front side intake working chamber 12r. Therefore, during the above-mentioned time τ1, the front side intake working chamber +2r, which is in the first half of the intake stroke, is filled with intake air through the communication hole I3, and the pressure in the rear side intake working chamber 12r shifts without being increased. .

Then, the primary (secondary) intake port 2r of the rear cylinder R (
5r), the rear side opening 13r of the communication hole 13 starts to be opened again around the timing when it is closed, and then the rear side opening 13r is opened. Regarding the front cylinder F, when the intake bottom dead center BDC is passed, the primary (secondary) intake port 2f (51') is closed (in terms of crank angle,
For example, ABDo40°), and after a predetermined timing delay, the front side opening +3[' of the communication hole 13 is closed (
In terms of crank angle, for example ABDo 135°).

After this intake bottom dead center BDC until the front side opening 13F is closed, both the front side and rear side openings ILf and 13r of the communication hole 13 are open, and for this time τ, (τ, = τ1) During this time, arrow B is moved from the high-pressure front intake working chamber 12f to the rear intake working chamber 12r.
The intake air flows as shown in the front side intake working chamber 12r.
The pressure increase is suppressed, and the rear side intake working chamber 12r is filled with intake air.

When the front side opening +3f of this communication hole 13 is closed, the compression stroke starts in the front side air cupboard 1, but the volume of the intake working chamber 12r in this closed position is the same as that of the throttle valve 9. Assuming that air is taken in with the engine fully open, the amount of intake air is set to be greater than the required charge during idling + Rm, in other words, the minimum required charge 111. In other words, the communication shown by the imaginary line C in FIG. Closing timing of hole I3 is 1 air-A-s [i, 1 mouth Q1 time! 10
Set the 11 μf small bone 1 and the right side to the trailing side when viewed in the rotational direction of the rotor from the position that satisfies the measurement.

Next, a control method for the control valve 14 and the throttle valve, particularly the primary throttle valve 9, provided in the communication hole 13 will be explained.

FIG. 4 shows the control system. As shown in the figure, the secondary throttle valve 11 is interlocked with the primary throttle valve 9 which is opened and closed by the accelerator pedal 16 via a link mechanism 17, and the communication hole 13 An actuator 18 made of an electromagnetic solenoid is provided for the control valve 14 . This actuator 18 is provided with a control circuit 20 for controlling the operation of the actuator 18 and controlling the opening and closing of the control valve 14 .

This control circuit 20 basically uses human power to detect the throttle opening of the primary throttle valve 9, which is detected by a throttle opening sensor 21 provided for the secondary throttle valve 9. A sensor, more specifically a pressure sensor 22 for detecting abnormal boost pressure
, coolant temperature sensor to detect engine overheating.

23. The actuator 18 is controlled as follows using the outputs of the rotational speed sensor 24 and the knocking sensor 25 for detecting engine overspeed as human power.

When an ON signal is applied from the control circuit 20, the actuator 18 opens the control valve I4 and maintains the control valve 14 in the fully open state as shown in FIG.

As shown in FIG. 5, which shows the throttle opening of the primary throttle valve 9 and the open/closed state of the control valve 14, the throttle opening is the set opening θ. During the following low-load operation, the control valve 14 is fully open at the set opening θ. When the value exceeds , the control valve 14 is fully closed.

In the control system shown in FIG. 4, the throttle opening is the set opening θ. When the control circuit 20 determines that this has been reached, the control circuit 20 switches the signal applied to the actuator 18 from on to off, and fully closes the control valve 14.

Note that during idling operation, the control valve 14 may be fully opened.

In this case, the above setting opening degree θ. is set taking into consideration the output characteristics of the engine. That is, the communication hole 13 is in the open state.
We experimentally found the limit throttle opening at which the engine output no longer increases when the throttle opening is increased while holding the throttle position, and this is the set opening θ. shall be.

Then, this set opening degree θ. control valve 14 when the
It is mainly the engine charger that closes the
This is to ensure that the output is as high as possible.

FIG. 6 shows the rotational speed-output torque characteristic obtained when the above-mentioned intake system is employed, using the throttle opening degree θ as a parameter. In this case, the throttle opening degree 0 is set slightly wider than the throttle opening degree set in a conventional system without a communication hole, and the engine is operated with the intake negative pressure considerably reduced. In this way, pumping losses during low load operation can be significantly reduced, and
The same control as a conventional engine is possible.

In addition to the above-mentioned basic control, the control circuit 20 executes countermeasures when an abnormality occurs in the engine as follows.

Now, any of the various sensors 22, 23, 24, 25 installed to detect abnormalities in the engine is activated, resulting in abnormal boost pressure, overheating, or overspeeding.

When an engine abnormality such as knocking is detected, the control circuit 20 unconditionally activates the actuator! 8 and opens the control valve I4.

If the control valve 14 is opened unconditionally when an abnormality occurs in the engine as described in Kitagi, the output of the engine will be significantly reduced, and engine abnormality will be avoided.

In this case, the opening degree of the control valve I4 does not necessarily need to be fully open, but it is better to set a predetermined angle in advance. It may be possible to shift to normal control when the output falls, but for example, the open state may be maintained for a certain period of time from the fall of the sensor to reliably avoid recurrence of engine abnormality.

The present invention is not limited to a two-cylinder rotary piston engine, nor is it limited to an electromagnetic type actuator for a control valve, but may be one using intake negative pressure as a power source.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional explanatory view of a rotary piston engine according to an embodiment of the present invention, Fig. 2 is an explanatory side view of the rotary piston engine showing the shape of the communication hole, and Fig. 3 is an explanatory side view of the rotary piston engine showing the shape of the communication hole. Figure 4 is a schematic configuration diagram showing the control system of the throttle valve and control valve, Figure 5 is an opening graph showing the opening and closing operations of the throttle valve and control valve, and Figure 6 is a graph showing the change in engine speed. It is a graph showing the change in output torque when the throttle opening is used as a parameter. F, R...Cylinder, 8.10...Intake passage,
9゜11... Throttle valve, 13... Communication hole,
1.1... Control valve, I8... Actuator, 20... Control circuit, 22, 23, 24.
25...Sensor. Patent applicant: Mazda Motor Corporation agent: Patent attorney: Figure 6: Fit diagram for two idiots

Claims (1)

[Claims] (1) In a rotary piston engine in which the cylinders are communicated by a communication passage that closes later than the main intake port, and intake air is circulated between the cylinders according to the phase difference between the cylinders, the communication passage is opened and closed. 1. An intake device for a rotary piston engine, comprising a control valve and a control means for opening the control valve when an abnormality occurs in the engine.