JPS6390626A - Pumping loss reducer for rotary piston engine - Google Patents

Abstract

PURPOSE:To make good combustion securable even at the time of an on-off valve coming into a state of being closed, by installing this on-off valve in an interconnecting port which interconnects an interval between operating chambers of two cylinders in each of both suction and compression strokes, and installing a pair of fuel injection nozzles at both sides of the on-off valve in closure. CONSTITUTION:In case of a 2-cylinder engine having both cylinders A and B with rotor chambers (operating chambers) 8 and 9 where each of rotors 10 and 11 are housed free of rotation, an interconnecting port 41, interconnecting the operating chamber of the cylinder on one side in a suction stroke to that of the cylinder on the other in a compression stroke, is formed in an intermediate housing which partitions off these rotor chambers 8 and 9. And, in this intermediate housing, there are provided with an on-off valve 42 for opening or closing this interconnecting port 41, and a symmetrical pair of fuel injection nozzles 50a and 50b for spraying fuel to both sides of the on-off valve 42 in closure. And, fuel injection is performed from a common fuel injection valve 43 through each of these fuel injection nozzles 50a and 50b, whereby fuel supply to these cylinders A and B at the time of the on-off valve 42 being closed is made performable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pump loss reduction device for a rotary piston engine.

(Prior Art) In an engine that performs load control by adjusting the amount of intake air using a throttle valve disposed in an intake passage, when the opening degree of the throttle valve is small, the throttling loss, that is, the pumping loss, increases.

Therefore, in rotary piston engines, in order to reduce pumping loss due to the throttle valve, the intermediate housing that separates the first cylinder and the second cylinder is provided with a working chamber for one cylinder in the intake stroke and the other cylinder in the compression stroke. There is a device in which a communication port is formed that communicates with the working chamber of the cylinder, and an on-off valve that opens when a predetermined operating range is reached is provided in this communication port (Japanese Patent Laid-Open No. 58-1724).
(See Publication No. 29). In other words, by utilizing the flow of intake air between the first and second cylinders through the connecting bolt, it is possible to open the throttle valve more widely, thereby reducing pump loss. will be done.

Also, in rotary piston engines.

Similar to a normal reciprocating engine, fuel is supplied to the intake passage, but the location of this fuel supply can have a large effect on combustibility, etc. For example, the fuel supply location may be changed depending on the engine load. Various efforts have been made to optimize this. Specifically, fuel injection valves are already put into practical use in which fuel injection valves are provided on the upstream and downstream sides of the intake passage, and fuel is injected from a preferred position depending on the operating state of the engine.

(Problems to be Solved by the Invention) As mentioned above, in systems that utilize communication ports to reduce pump loss, the engine temperature decreases due to a reduction in compression pressure and large movement of the air-fuel mixture through the communication ports. This caused new problems such as a decrease in combustion rate and an increase in HC.

Therefore, an object of the present invention is to solve the problem in reducing pump loss by optimizing the fuel supply mode, assuming that the communication port is used to reduce pump loss. First, it is an object of the present invention to provide a pump loss reduction device for a rotary piston engine that can provide more preferable fuel supply depending on the operating state of the engine.

(Means and operations for solving the problems) In order to achieve the above-mentioned object, the present invention has the following configuration. That is, a communication port is formed in the intermediate housing that defines the cylinders of ~ and the other cylinders, and communicates the working chamber of one cylinder in the intake stroke with the working chamber of the other cylinder in the compression stroke; an on-off valve provided in the communication port and opened when a predetermined operating range is reached; and a pair of left and right on-off valves formed on the intermediate housing for injecting fuel to both sides of the on-off valve in the closed state. It has a configuration including a fuel injection port and.

In this way, when the communication port is open, by injecting fuel into the communication port, the movement area of the air-fuel mixture is reduced compared to when the air-fuel mixture is supplied from the intake passage. The amount of fuel adhering to the fuel is reduced (reduced quenching), reducing HC and improving fuel efficiency. In addition, almost all of the injected fuel can be carried by the rapid movement of the intake air through the communication port, and the mixture supplied through the communication port is rich, that is, partially enriched. It is possible to form a mixture layer (stratification) and improve the combustion rate. Of course, it becomes possible to shorten the distance traveled by the fuel, which is favorable in terms of ensuring responsiveness.
Furthermore, the oil washing effect caused by the fuel is also reduced, making it possible to reduce oil consumption.

In addition to the above, even when the on-off valve, that is, the communication port, is closed, fuel can be injected into each cylinder from the pair of left and right fuel injection ports that are formed avoiding the on-off valve, so that the on-off valve closes. More preferable combustion can be obtained even in a low operating range. For example, even in light load ranges including idle, compared to when fuel is injected into the intake passage,
It is possible to achieve further combustion stability using the above-mentioned stratified combustion, a reduction in HC by shortening the distance traveled by the fuel, improvement in fuel efficiency, and reduction in fuel consumption.

Furthermore, the fuel injection valve, which injects fuel through a pair of left and right fuel injection ports formed on both sides of the on-off valve, can be used for two cylinders, so conventionally it is installed at the downstream end of the intake passage for each cylinder. The conventional fuel injection valve can be replaced with a fuel injection valve that injects fuel on both sides of this on-off valve. In this case, fuel injection valves with two injection holes have already been put into practical use, so if this two injection valve is used, it is possible to reduce the overall number of fuel injection valves. .

(Example) Examples of the present invention will be described below based on the attached drawings.

QT, In Figure 1, the housing of the engine body l is sequentially connected from one end of the output shaft 2 (eccentric shaft) to the other end by a side housing 3, a rotor housing 4, an intermediate housing 5, a rotor housing 6, and a side housing 7. The rotor 10 or 11 is housed in the two rotor chambers 8.9 defined by the intermediate housing 5. In this way, the engine body 1 accommodates the rotor 10 or 11. The first cylinder A and the rotor 11 have
It is said to be for two cylinders, with the second cylinder B having two cylinders.

As shown in FIG. 2, each rotor chamber 8 (9) has three working chambers 12A (
12B), 13A (13B), and 14A (14B)
It is defined as In this Figure 2, 15A (
15B) is a secondary intake port defined in the side housing 3 or 7 (the primary intake port formed in the intermediate housing 5 is not shown), 16A ("16B)"
) is an exhaust port, and 17A (17B) is a spark plug. Therefore, in the state shown in FIG. 2, in the working chamber of the first cylinder A, 12A is in the intake stroke, 13A is in the explosion stroke (initial stage), and 14A is in the exhaust stroke. Further, the working chamber of the second cylinder B is in the exhaust stroke a (final stage) for 12B, in the compression stroke for 13B, and in the explosion (final stage) stroke for 14B.

The intake passage 21 including the intake port is provided with a surge tank 22 in the middle, and the upstream side of the surge tank 22 is a single common intake passage 23. , an air cleaner 24, an air flow meter 25, and a throttle valve 26 are provided. In addition, the intake passage downstream of the surge tank 22 includes the primary and secondary independent intake passages 27A and 28A on the side of the first cylinder A, and the secondary intake passage.
Primary and secondary independent intake passages 27B and 28B for cylinder B
It is configured as a total of four independent intake passages. This primary independent intake passage 27A (27B) is a primary intake port 15A (27B) formed in the intermediate housing 5 as is known.
15B), and a secondary independent intake passage 28A (
28B) is connected to a secondary intake port formed in the side housing 3 (7). A fuel injection valve 30A (30B) as a first fuel injection valve is disposed in the secondary independent intake passage 28A (28B) at a sufficiently upstream portion thereof. Then, the secondary independent intake passage 28A (2
8B) includes a shutter valve 3 that is opened only in high load areas.
1 is arranged.

The intermediate housing 5 includes, as shown in FIGS. 1 to 3,
A communication port 41 is formed to communicate between the inner cylinders A and B. This communication port 41 is connected to the working chamber of one cylinder in the intake stroke (the working chamber 12 of the first cylinder A in FIG. 2).
A) and the working chamber of the other cylinder in the compression stroke (in FIG. 2, the working chamber 13B of the second cylinder B) are communicated with each other, and its opening position is determined. That is, communication port 4
1 is connected to the intake port 1 by the rotor 10 or 11.
It is designed to close after a delay after 5A or 15B is closed (the same applies to the secondary intake port).

Note that this communication port 41 has an extremely short length (approximately 5 cm) corresponding to the thickness of the intermediate housing 5, and is formed linearly.

The intermediate housing 5 is provided with an on-off valve 42 for opening and closing the communication port 41 and a fuel injection valve 43 for injecting fuel into the communication port 41. This fuel injection valve 43 constitutes a second fuel injection valve, and in the embodiment, is used commonly for the first cylinder A and the second cylinder B.

As shown in FIGS. 3 and 4, the on-off valve 42 is of a butterfly type, and is driven to open and close via a rod 47 by an electromagnetic actuator 48 such as a step motor or a DC motor. Furthermore, a pair of left and right fuel injection ports 50a and 50b are opened in the communication port 41. The fuel injection ports 50a and 50b correspond to the on-off valve 4 in the closed state.
The fuel injection port 50a is always in communication with the first cylinder A side through the communication port 41, and the fuel injection port 50b is always in communication with the second cylinder B side through the communication port 41. ing. Since the fuel injection valve 43 is commonly used for each cylinder A and B, it is of a two-injection type and is located on the upstream side of the partition wall 5a that defines both fuel injection ports 50a and 50b. The fuel injector 43 is located in the mounting hole 49 (the upstream confluence of 50a and 50b).
is inserted. As a result, one side of the fuel injected from the fuel injection valve 43 is directed toward the fuel injection port 50a, and the other side is directed toward the fuel injection port 50b.

Note that an air passage 54 for supplying assist air for promoting vaporization and atomization of fuel injection is opened in the mounting hole 49.

FIG. 5 shows that the on-off valve 42 is of a butterfly type,
This figure shows a case where the fuel injection valve 43 is composed of two fuel injection valves 43a and 43b dedicated to each cylinder A and B.

9 and 10 show the on-off valve 4 for opening and closing the communication port 41.
2' is a rotary type, and the fuel injection valve 43 is common to cylinders A and B. That is, the on-off valve 42' includes a bottomed cylindrical housing 44 that constitutes a part of the communication port 41, and a rotor 45 as a valve body that is rotatably fitted into the housing 44.
A communication port 46 is formed in the rotor 45 and passes through the rotor 45 in the radial direction. This allows rotation -/-
Depending on the rotational position of 45, the communication port 41 is opened or closed (see FIG. 10). The first rotor 45 is driven to open and close by an actuator 48 via its rod 47'.

In FIG. 2, U is a control unit composed of a microcomputer, and this control unit U receives an intake air amount signal from an air flow meter 25 and a rotation speed sensor 61.
The engine speed signal from the engine is input manually. Further, the control unit U controls the opening and closing of the on-off valve 42 (42') and the fuel injection from each of the fuel injection valves 30A, 30B, and 43.

Note that the control unit U basically includes a CPU, a ROM,
Although it is equipped with a RAM, a CLOCKt, a human output ink face, and a drive circuit, the method of using this microcomputer itself has been known for a long time, so further explanation will be omitted.

Next, an overview of the control of the control unit U mentioned above will be explained. First, the opening/closing range of the opening/closing valve 42 (42) is set using the engine speed Ne and the engine load (intake air amount Qa) as parameters, as shown in FIG. 6, for example. That is, the on-off valve 42 is closed both near the idle region (region work) and at high rotation or high load (region ■), and in the region H, the on-off valve 42 is opened. In addition, the fuel injection valve in which fuel is injected is only the second fuel injection valve 43 in areas 1 and 2, and in area 3, both the first and second fuel injection valves 3O
It is said to be from A, 30B, and 43.

FIG. 7 also shows an operating region I in which the communication port 41 is open.
It shows an example of the combustion cycle at I, the direction of exchange of intake air through the communication port 41, and the timing of fuel injection from the fuel injection valve 43 common to each cylinder A and B. That is, in Fig. 7, ■0 is the intake port open timing, IC is the intake port closing timing, and LO is the communication port 4.
1 shows the opening timing, and LC shows the communication port closing timing. The shaded area is when the intake air flows back and forth between the two cylinders A and B, and the white arrow indicates the flow direction of the intake air. Four strokes of intake, compression, explosion, and exhaust are performed per rotation of the rotor 10 or 11, while the output shaft 2 rotates three times per rotation of the rotor.
The rotation angle of rotors 10 and 11 per stroke is 270'', and the rotational phase difference between rotors 10 and 11 is 1 because there are two cylinders.
It is 80″.

Based on the premise that the fuel injection valve 43 for common use is located north of this point, the timing of fuel injection from the common fuel injection valve 43 is such that, in the embodiment, the communication port 41 is open, as shown by injection pulses ■ and ■ in FIG. When set to exit. In the example shown with this injection pulse ■, the injection start and end are both when the communication port 41 is open, and the injection pulse ■
In another example, injection is started when the communication port 41 is closed, and injection is ended when the communication port 41 is open.

As mentioned above, in the operating region II, the communication port 41 is opened at a predetermined timing as shown in FIG.
Intake air flows from one cylinder in the compression stroke to the other cylinder in the intake stroke. At this time, all of the fuel injected into the communication port 41 from the common fuel injection valve 43 rides on the fast intake air flowing through the communication port 41, becoming rich and stratified into the working chamber during the intake stroke. and supplied. Since the fuel supplied from this communication port 41 travels a short distance until it is combusted, the amount of fuel that adheres to the wall surface of the housing 3.4.5.6.7 and the surface of the rotor 10.11 is small. Become something. As a result, an increase in combustion speed, a decrease in HC, and an improvement in fuel efficiency can be obtained. Of course, in this operating region II, as the distance traveled by the fuel is shortened, the effect of washing away the lubricating oil by the fuel is also weakened.

It becomes possible to reduce oil consumption. The fuel injection timing is a 180° period when the fuel injection timing is common to each cylinder A and B, as shown in Fig. 4-1O, and a cycle of 180° when it is used exclusively for each cylinder as shown in Fig. 5. It has a 360° cycle like the fuel injection valves 30A and 30B provided in the above.

Further, in the operation area work, the on-off valve 42 (42') is closed, but fuel is supplied from the fuel injection valve 43 through the communication port 41. As a result, even in this operating range, the effects of stratified combustion, HC reduction, fuel efficiency improvement, and oil consumption reduction described above can be obtained.

Further, in the operating region (3), the on-off valve 42 (42') is closed, and the first. Both second fuel injection valves 30A, 30
Fuel is injected from B. As a result, the optimum settings are made in a well-balanced manner between securing compression pressure, securing output by promoting fuel vaporization and atomization (fuel supply from 30A and 30B), and the above-mentioned advantages of supplying fuel through the communication port 41. .

Regarding the control contents of the control unit/l'U mentioned above,
This will be explained with reference to the flowchart shown in FIG. Note that in the following explanation, P indicates a step.

First, the engine speed Ne and the intake air amount Qa are detected at PL, and then at P2, the fuel injection amount T to be injected per cylinder is determined based on both Ne and Qa.
P is calculated.

At P3, it is determined whether the current operating state of the engine is in the operating range H shown in FIG. When YES in P3, the on-off valve 42 is opened in P4, and then in P5, the fuel injection amount TP at P2 is set as the fuel injection amount TPL from the common fuel injection valve 43 (the first fuel injection valve 30A , the fuel injection amount TPP from 30B is set to O). Thereafter, the process waits for a predetermined fuel injection timing at P9, and when the predetermined fuel injection timing arrives, TPP and TPL are output at PIO (however, TPP is O).

On the other hand, when the determination in P3 is NO, the on-off valve 42 is closed in P7, and then it is determined in P7 whether or not the current engine operating state is in the operating range.

If the determination in P7 is No, it means that the operation is in the operating range ■, so the process moves to P8 and the first fuel injector 3OA (3
0B), and the fuel injection amount TPL from the second fuel injection valve 43 is T.
Set as PXC2 (distributes TP to cl:c2 - but neither cl nor c2 is O). This Pl
After O or Fil, the processing from P9 described above is performed.

When the determination in P7 is YES, the second fuel injection valve 4
In order to perform fuel injection only from P3, the processing from P5 described above is performed.

Although the embodiments have been described above, the present invention is not limited thereto, and includes, for example, the following cases.

(2) When the control unit U is configured by a computer, it may be of either a digital type or an analog type.

(The rethrottle valve may be divided into a primary throttle valve and a secondary throttle valve (the opening of the primary throttle valve increases and begins to open at the connections that are in a predetermined high load area). In this case, when providing a surge tank, surge tanks may be configured separately for primary use and secondary use.

(3) Without dividing the intake passage into primary and secondary use,
It may be of a type that always supplies intake air in the entire load range.

(Effect of the invention) As is clear from the above description, the present invention has been made.

In a predetermined operating range in which the on-off valve is opened, it is possible to reduce the pump loss by utilizing the communication port, and to prevent the combustion rate from decreasing and the HC from increasing when the pump loss is reduced.

In addition, even in the operating range where the communication port is closed, fuel can be supplied from the communication port side avoiding the on-off valve, compared to the conventional case where fuel was supplied from the downstream end of the intake passage. As a result, more optimal fuel supply can be performed from the viewpoints of flammability, HC reduction, fuel efficiency improvement, and oil consumption reduction.

In addition to this, there is also the effect that the number of fuel injection valves may be the same or smaller than before. In particular, compared to the conventional fuel injection valve that was installed in the intake passage, a fuel injection valve that injects fuel into the communication port only when the on-off valve is opened is added. In the present invention, among the fuel injection valves provided in the intake passage, those at the downstream end can be discarded by the IF, so the number of fuel injection valves can be reliably reduced.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing the engine main body portion of a rotary piston engine to which the present invention is applied. FIG. 2 is an overall system diagram showing one embodiment of the present invention. FIG. 3 is a sectional view of main parts showing the communication port portion in detail. FIG. 4 and FIG. 5 are cross-sectional views showing the on-off valve in the closed state and the fuel injection state on both sides thereof. FIG. 6 is a graph showing an example of setting the operating range and fuel supply center for opening and closing the on-off valve. Figure 7 shows the opening and closing of the intake port, the opening and closing of the communication port, and the fuel■
Graph showing the relationship with shooting timing. FIG. 8 is a flowchart showing a control example of the present invention. Figure 9,? The JSlo diagram shows a modification of the present invention,
FIG. 9 is a sectional view corresponding to FIG. 3; FIG. 10 is a sectional view corresponding to FIG. 4. A: 1st cylinder B: 2nd cylinder 1: Engine body 2: Output shaft 5: Intermediate housing 8.9: Rotor chamber 10.11 N Rotor 12A, 12B Two working chambers 13A, 13B = Working chamber 14A, 14B: Working chamber 15A, 15B: Intake port (secondary) 16A, 16B = Exhaust port 17A, 17B: Spark plug 21: Intake passage 23: Common intake passage 26: Throttle valve 27A, 27B: Independent intake passage (primary - 1st) 28A ,
28B: Independent intake passage (secondary-first) 30A, 30B=
Fuel injection valve (primary) 30A, 30B: Fuel injection valve (secondary) 41: Communication port 42.42': Open/close valve 43: Fuel injection valve (common - second) 45: Rotor 46 dual communication port 48: Actuator (for opening/closing) 49: Mounting holes 50a, 50b: Fuel injection port

Claims (1)

[Claims] (1) A communication port that is formed in an intermediate housing that defines one cylinder and another cylinder and communicates the working chamber of one cylinder in the intake stroke with the working chamber of the other cylinder in the compression stroke; an on-off valve provided in the communication port and opened when a predetermined operating range is reached; and a pair of left and right on-off valves formed on the intermediate housing for injecting fuel to both sides of the on-off valve in the closed state. A pump loss reduction device for a rotary piston engine, comprising: a fuel injection port;