JPS6334290B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an intake system for a rotary piston engine.

Conventionally, a polygonal rotor moves inside a casing consisting of a rotor housing having a trochoidal inner circumferential surface and side housings disposed on both sides of the rotor housing, and rotates a planet while sliding its top edge against the trochoidal inner circumferential surface. rotational movement, intake, compression, explosion,
In a rotary piston engine that performs each expansion and exhaust stroke, the exhaust and intake stroke working chambers overlap, meaning that the intake port and exhaust port open simultaneously for one working chamber, and the pressure difference between the two ports causes Exhaust gas remaining in the exhaust port is sucked into the intake passage from the intake port, and during the intake stroke in which this working chamber expands, the exhaust gas in the intake passage is brought into the intake stroke working chamber together with the fresh air mixture. When the air-fuel mixture is diluted with inert exhaust gas, the spark plug misignites the air-fuel mixture, a so-called misfire phenomenon, which causes problems such as poor driving performance and an increase in harmful components in the exhaust gas due to poor combustion. It is recognized that this can happen.

Particularly in light load operating ranges, including idling, where the filling efficiency of the fresh air mixture is low, the negative effects of the above overlap are noticeable. The ignitability was maintained in the operating range.

However, the above method supplies unnecessary excess fuel, which inevitably leads to a deterioration in fuel efficiency, which is a major obstacle in reducing fuel consumption in rotary piston engines and responding to requests for resource conservation. ing.

Therefore, in order to improve the ignition performance in the light load operating range including idling without setting the air-fuel mixture to be rich as described above, the present invention provides an intake port so as not to have the above-mentioned overlap. This suppresses the introduction of exhaust gas into the intake stroke working chamber, maintains good ignitability with a lean air-fuel mixture, and improves fuel efficiency.

That is, in the present invention, when one working chamber transitions from the exhaust stroke to the intake stroke, the exhaust port is set to substantially close and then the intake port opens, thereby eliminating overlap. In this case, there are generally two types of intake ports: a peripheral port type in which the intake port is opened on the inner peripheral surface of the rotor housing, and a side port type in which the intake port is opened on the inner surface of the side housing. With the port type, it is difficult to set it so that there is no overlap with the exhaust port due to its structural limitations. Therefore, the present invention employs the latter side port type intake port provided in the side housing.

However, in the above-mentioned side port type intake port, its opening shape is restricted by various requirements, and if it is set so that there is no overlap with the exhaust port as described above, the opening area becomes narrow and it is difficult to handle high loads. Sometimes, sufficient air-fuel mixture cannot be supplied, resulting in problems such as reduced output performance.

In other words, the contour shape of the intake port opened in the side housing is regulated so that the inner edge on the center side is outward from the sliding trajectory of the oil seal, and the outer edge on the outer periphery side regulates when the intake port begins to open. On the other hand, the upper edge regulates the closing timing of the intake port, and as described above, in order to delay the opening timing so as to eliminate overlap with the exhaust port, the outer edge must be set inward. This narrows the opening area of the intake port, but the only way to increase this without causing the overlap is to widen the upper edge and delay the closing timing. However, delaying the closing timing causes a phenomenon in which the intake air-fuel mixture is blown back into the intake passage under high load and low rotation, leading to a decrease in filling efficiency and compression pressure, and deteriorating the operating performance at low rotation. .

In view of this, the present invention separates the intake port into a light load intake port including idle and a high load intake port, and the light load intake port is set to open after the exhaust port is substantially closed. This eliminates overlap, suppresses the introduction of exhaust gas, and improves the intake flow rate to promote fuel atomization, making it possible to ignite with a lean mixture even during idling, improving fuel efficiency. The load intake port is provided with a control valve that opens at high load near the opening on the working chamber side, so that only the light load intake port opens during light loads including idling, and the light load intake port opens during high loads. In addition, by opening the high-load intake port that closes a set value later than the light-load intake port, eliminating the overlap and closing earlier, the opening area of the intake port is reduced. This eliminates the decrease in output performance, and also closes the control valve during light loads to eliminate exhaust gas from being brought into the high-load intake port and light-load intake passage. The present invention provides an intake system for a rotary piston engine that simultaneously satisfies fuel efficiency in the range and output performance in the high load range.

Embodiments of the present invention will be described below with reference to the drawings. In FIGS. 1 to 4, 1 is a rotor housing having a trochoidal inner peripheral surface 1a;
2, 2 are side housings arranged on both sides of the rotor housing 1;
A polygonal rotor 3 moves planetarily in a casing constituted by the and side housings 2, 2 with its top edge slidingly in contact with the trochoidal inner circumferential surface 1a to form a working chamber 4. There is.
The rotor 3 is supported by an eccentric shaft 5 (see Figures 3 and 4), and the rotor 3 is provided with an apex seal 6, a corner seal 7, and a side seal in order to maintain gas sealing between the working chambers 4. 8 is attached, and an oil seal 9 is attached to the center side.

Further, 10 and 11 are the side housing 2
A light load intake port including an idler and a high load intake port are formed independently from each other and have working chamber side openings 10a and 11a opened on the inner side, respectively, and 12 is an intake manifold for both the ports 10 and 11. This is a dual carburetor that supplies air-fuel mixture through 13.

Working chamber side openings 10a, 11a of both ports above
are opened and closed by the rotation of the rotor 3, and as shown in FIG. 3, the light load intake port 10 opens after the exhaust port 14 opened in the rotor housing 1 is substantially closed, and closes at an early stage. On the other hand, the high-load intake port 11 is set to close with a delay of a set value after the light-load intake port 10 closes. In addition, 15 in FIG. 3 is a spark plug.

Next, reference numeral 16 denotes a control valve that is provided in the high-load intake port 11 in close proximity to its working chamber side opening 11a and opens when the load is high.The control valve 16 is a circular hole-shaped high-load intake port. A communication hole 1 is rotatably inserted into the opening 11 and communicates with the opening 11a at the tip end.
The valve body 17 is composed of a cylindrical valve body 17 having a diameter 7a, and an actuator 18 that rotates the valve body 17 to open and close it, and the actuator 18 is configured to operate using exhaust pressure.

In the actuator 18, 18a is a diaphragm that divides the inside of the case 18b into a pressure chamber 18c and an atmospheric chamber 18d, 18e is a shaft connected to the diaphragm 18a, and 18f is an atmospheric chamber 1.
8d is a compressed spring, 18g is an adjustment screw, 18h is an exhaust pressure introduction pipe to the pressure chamber 18c,
18i is a solid type bellows in which slits are alternately formed on the inner and outer peripheries. Further, the tip of the shaft 18e of the actuator 18 is connected to the link 1.
9, connected to the rod 21 via the lever 20;
The rod 21 passes through the intake manifold 13 and is inserted into the high-load intake port 11, and its tip is connected to the base of the cylindrical valve body 17 via a pin 22. Furthermore, 23 is a rubber seal interposed between the rod 21 and the intake manifold 13,
The intake negative pressure generated in the secondary intake passage 25 prevents external dust from being sucked in.

The exhaust pressure introduced into the pressure chamber 18c of the actuator 18 changes in accordance with the intake amount of the air-fuel mixture into the engine.
At high loads, when the pressure introduced into the
The shaft 18 is biased downward against the urging force of f.
The valve body 17 is moved through the rod 21 by the retracting operation of e.
is rotated to communicate the communication hole 17a and the opening 11a to open the high-load intake port 11,
When the exhaust pressure is lower than a set value and the load is light, the shaft 18e protrudes due to the urging force of the spring 18f, and closes the valve body 17 via the rod 21.

Furthermore, 24 is a primary carburetor 12A having a primary throttle valve 26 of the carburetor 12, and an intake manifold 13.
25 is a secondary carburetor 12B having a secondary throttle valve 27 of the carburetor 12 and an intake manifold 13;
A secondary intake passage constituted by a passage independently formed within the light load intake port 10.
The primary intake passage 24 is connected to the high-load intake port 1.
1 are connected to secondary intake passages 25, respectively.

In the carburetor 12, 28 is a primary side bench lily part, 29 is a secondary side bench lily part, 30 is a primary side main nozzle (the secondary side is not shown), 31 is a float chamber, 32 is a main jet, 33 is an air bleed, and the secondary throttle valve 27 is the primary carburetor 1.
A diaphragm actuator (not shown) opens the ventilator when the negative pressure of the 2A ventilator exceeds a set value.

Next, the operation of the above embodiment will be explained. First, in a light load range including idle, the secondary throttle valve 27 of the carburetor 12 is closed, and the exhaust pressure acting on the actuator 18 is also small, and the control valve 16 closes the high load intake port 11. Therefore, the air-fuel mixture from the primary intake passage 24 is supplied to the working chamber 4 through the light-load intake port 10.

The light load intake port 10 is the exhaust port 1.
4 is set to open after being substantially closed, and there is no overlap with the exhaust port 14, which greatly reduces the amount of exhaust gas brought in due to this overlap. Since the air-fuel mixture is supplied from the primary intake passage 24, which has a small opening area and is formed independently, the flow rate of the air-fuel mixture is high and the fuel vaporizes.
Atomization is good, and as a result, combined with the reduction in the carry-in of exhaust gases, good ignition performance can be obtained even with a thin air-fuel mixture, resulting in a significant improvement in fuel efficiency under light loads, including idle conditions. .

In addition, when the above light load is applied, the high load intake port 1
1 is closed near the opening 11a by the control valve 16, and the dead volume in the port is extremely small, so the amount of exhaust gas brought in does not increase, and moreover, the intake air-fuel mixture is not transferred to the high-load intake port 11. Good idling and light load operation can be obtained without blowback.

On the other hand, in a high load range, the secondary throttle valve 27 of the carburetor 12 opens and the exhaust pressure acting on the pressure chamber 18c of the actuator 18 increases, and when the set load state is exceeded, the actuator 18
is activated, and by rotating the cylindrical valve body 17 of the control valve 16, the communication hole 17a of the valve body 17 and the opening 11a of the high-load intake port 11 are communicated with each other and opened. The air-fuel mixture from the secondary intake passage 25 is also supplied from the port 11 .

At this time, the opening 11a of the high-load intake port 11 is opened from the upper part (leading side) by the control valve 16 as shown in FIG. Through opening 1
The air-fuel mixture supplied from 1a is configured to be ejected in the leading direction, that is, toward the vicinity of the spark plug 15, so that better combustion performance can be obtained.

At the time of the above-mentioned high load, high output performance is obtained by supplying a large amount of fresh air mixture from both the light load and high load intake ports 10 and 11,
Good high-load, high-speed operation can be obtained. In particular, the high-load intake port 11 closes later than the light-load intake port 10, that is, the end of the intake stroke is delayed, so more air-fuel mixture is supplied and charging efficiency is improved. be. Since the intake inertia is large during this high load, even if the high load intake port is open, the intake air-fuel mixture will not blow back into the intake port and reduce the filling rate.
Note that the closing timing of the high-load intake port 11 during high-load, low-speed operation is limited due to the relationship with intake air blowback, etc., but it is set to an optimal value from the perspective of improving output performance during high-load, high-speed operation. .

In the above embodiment, the outer peripheral surface of the cylindrical valve body 17 of the control valve 16 is coated with a fluororesin film to ensure rotational operation of the valve body 17 even in poor lubrication conditions. is preferred.
Further, the communication hole 17a of the control valve 16 is formed larger than the opening 11a of the high-load intake port 11. Furthermore, the form and operation method of the control valve 16 and the actuator 18 can be changed in various designs, and the signal for opening at high loads can also be changed in response to the engine load state in addition to the exhaust pressure. The intake negative pressure, throttle valve opening, etc., or a combination of these and the rotation speed, etc. may be used.
However, if the control valve 16 is opened and closed using the exhaust pressure, the high-load intake port 11 will be opened only at high load and high rotation, and the light-load intake port 10 will be sufficient. This is preferable because it has the effect of improving the blowback phenomenon of intake air, which becomes a problem at high load and low rotation speeds where a sufficient amount of air-fuel mixture can be secured.

In addition, in the above embodiment, the light load intake port 1
0 and the high-load intake port 11 are provided in the same side housing 2, but one port may be provided in the opposite side housing 2.
In that case, the opening shape of the high-load intake port 11 may be set larger so as to overlap the opening shape of the light-load intake port 10. In the above example, the high-load intake port 11 is opened after the exhaust port 14 is closed, as shown in FIG. The influence of the dead volume is small, and the control valve is closed when the load is light, and only a small amount of exhaust gas is brought in by the dead volume, so it may be set so that there is some overlap with the exhaust port 14. Furthermore, engine cooling water is circulated around the outer periphery of the primary intake passage 24 communicating with the light-load intake port 10 to heat the intake air, and promoting vaporization of the fuel further improves ignitability. preferable.

Furthermore, as the fuel supply method, in addition to the method using the carburetor 12 as in the above embodiment, a fuel injection method may be adopted.

Therefore, according to the intake system of the present invention as described above, a light load intake port including an idle port and a high load intake port are provided in the side housing of a rotary piston engine, and the light load intake port is substantially the exhaust port. Set it to open after closing,
The high-load intake port is set to close a set value later than the light-load intake port, and a control valve is installed in the high-load intake port close to the opening on the working chamber side to close at light load and open at high load. By providing this, during light loads including idling, it reduces the carry-in of exhaust gas due to overlap with the exhaust port, improves ignition performance, enables good operation with a lean air-fuel mixture, and significantly improves fuel efficiency. At high loads with large intake inertia, the high-load intake port is opened to supply a large amount of air-fuel mixture to improve output performance, and it provides the most practically preferable fuel efficiency and output performance in all driving ranges. .

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional side view of the main parts of a rotary piston engine showing an embodiment of the present invention, Fig. 2 is a perspective view of the main parts of the side housing, and Fig. 3 is an explanatory diagram showing the timing of opening and closing of the intake port and exhaust port. , FIG. 4 is a longitudinal sectional view of the main part. 1... Rotor housing, 1a... Inner peripheral surface, 2
... Side housing, 3 ... Rotor, 4 ... Working chamber, 5 ... Eccentric shaft, 10 ... Intake port for light load, 11 ... Intake port for high load, 10a, 11
a...Opening, 12...Carburizer, 12A...Primary carburetor, 12B...Secondary carburetor, 13...Intake manifold, 14...Exhaust port, 16...Control valve, 17...Valve Body, 17a...Communication hole, 18...
Actuator, 19...Link, 20...Lever, 21...Rod, 22...Pin, 23...Rubber seal, 24...Primary intake passage, 25...2
Secondary intake passage, 26...primary throttle valve, 27...secondary throttle valve.

Claims (1)

[Claims] 1. In a rotary piston engine in which a polygonal rotor makes planetary rotation in a casing composed of a rotor housing having a trochoidal inner circumferential surface and side housings located on both sides of the rotor housing, the rotary piston engine is for light loads in which the side housing includes an idler. Provides an intake port and a high-load intake port,
The light load intake port is set to open after the exhaust port is substantially closed, the high load intake port is set to close a set value later than the light load intake port, and the high load intake port is set to open after the exhaust port is substantially closed. An intake device for a rotary piston engine, characterized in that a control valve is provided in a port close to an opening on the working chamber side and closes during light loads and opens during high loads.