JP4867902B2 - Fuel injection device for rotary piston engine - Google Patents

Description

  The present invention relates to a so-called direct injection type rotary piston engine, and more particularly to a combustion injection technique for improving the combustion stability thereof.

2. Description of the Related Art Conventionally, a direct injection type rotary piston engine is known in which injected fuel is concentrated in the vicinity of a spark plug at the time of ignition (see, for example, Patent Document 1). There, the fuel is injected along the flow of the vortex generated so as to swirl in the rotation direction of the rotor from the latter half of the intake stroke to the compression stroke as the rotor rotates. By doing so, stable stratified combustion can be realized and adhesion of fuel to the inner peripheral surface of the working chamber can be reduced.
JP-A-6-288249

  Here, in the fuel injection device of the direct injection type rotary piston engine, in order to form a uniform air-fuel mixture in the working chamber and burn it, the injected fuel is surely vaporized, atomized and uniformly diffused. is important. However, since the conventional fuel injection device for a rotary piston engine is configured to inject fuel toward the spark plug, there is a problem that it is difficult to ensure a sufficiently long time to vaporize and atomize the injected fuel. .

  The present invention has been made in view of the above points, and an object of the present invention is to provide fuel injection for a rotary piston engine that can accelerate fuel atomization, vaporization, and atomization by making fuel injection timing as early as possible. To provide an apparatus.

  In order to achieve the above-described object, in the present invention, the fuel injection valve is arranged on the trailing side of the intake port so that the fuel injection timing can be made as early as possible.

Specifically, the present invention includes a rotating shaft is housed in the rotor housing so as to extend in the horizontal direction the rotor, the rotary piston engine having a fuel injection valve for injecting fuel directly into the working chamber in the intake stroke The following solutions were taken for the fuel injection system.

That is, the invention of claim 1 includes an intake manifold connected to the intake port and extending outward from the rotor housing,
The fuel injection valve is disposed on the trailing side of the intake port facing the working chamber and below the intake manifold ,
The injection port of the fuel injection valve is formed to inject fuel toward the intake port.

According to this configuration, the fuel injection valve is disposed on the trailing side of the intake port and below the intake manifold, and the fuel is injected toward the intake port. Can be accelerated. That is, by performing fuel injection at the timing when the intake working chamber expands, it is possible to ensure as long as possible the time to vaporize and atomize the injected fuel and to diffuse it uniformly into the working chamber. Furthermore, the leading side air-fuel ratio in the intake working chamber can be increased to improve the combustibility on the leading side, and a rotary piston engine that exhibits excellent combustion performance can be realized. In addition, by injecting fuel toward the intake port, the kinetic energy of intake air can be efficiently used to promote fuel diffusion.

  Furthermore, if the fuel is injected by the fuel injection valve before the temperature in the intake working chamber is lowered by the air taken in from the intake port, the heat of the dilution gas flowing into the intake working chamber from the exhaust working chamber Thus, the injected fuel is instantly vaporized and atomized, which is advantageous in forming a uniform air-fuel mixture in the working chamber.

The invention of claim 2 is the invention according to claim 1,
The penetration of fuel injected toward the intake port is set to be shorter than the distance from the injection port of the fuel injection valve to the inner peripheral surface facing the injection direction in the working chamber. Is.

  According to this configuration, since the penetration of the fuel injected toward the intake port is set to be shorter than the distance from the injection port to the inner peripheral surface facing the injection direction in the working chamber, the inner peripheral surface of the rotor housing. The fuel can be prevented from adhering to the fuel, and uniform diffusion of the fuel can be realized stably.

The invention of claim 3 is the invention according to claim 1 or 2 ,
Before SL fuel injection valve is characterized in that the periphery of that is covered by the shielding member.

  According to this configuration, since the periphery of the fuel injection valve is covered with the shielding member, even if the exhaust manifold that circulates the high-temperature combustion gas is disposed below the fuel injection valve, it is emitted from the exhaust manifold. The radiant heat is insulated by the shielding member, and the fuel injection valve can be suppressed from being affected by the heat, and the reliability can be ensured.

The invention of claim 4 is the invention according to any one of claims 1 to 3 ,
The front end of the fuel injection valve is arranged to be inclined so as to be positioned substantially horizontally or below the rear end.

  According to this configuration, since the front end of the fuel injection valve is disposed so as to be substantially horizontal or below the rear end, the injected fuel does not accumulate in the injection port of the fuel injection valve. It is possible to suppress the carbon deposit produced by the combustion of fuel by the high-temperature dilution gas from adhering around the injection port.

A fifth aspect of the present invention is directed to any one of the first to fourth aspects ,
Is connected before Symbol exhaust port, an exhaust manifold that extends into the rotor housing outer together is disposed below the intake manifold,
The fuel injection valve is arranged between the intake manifold and the exhaust manifold and on the inner side in the extending direction than the end portions on the extending side of both manifolds.

According to this configuration, since the fuel injection valve is disposed between the intake manifold and the exhaust manifold and on the inner side in the extending direction from the ends on the extending side of both manifolds, the intake manifold and the exhaust manifold are connected to the vehicle. If it extends in the side direction, the impact from the outside can be reduced by the intake manifold and the exhaust manifold at the time of a side collision of the vehicle, the fuel injection valve can be protected, and safety can be ensured.

  As described above, according to the present invention, if fuel injection is performed at the timing when the intake working chamber expands, the time for vaporizing and atomizing the injected fuel is ensured as long as possible, and the fuel is uniformly diffused in the working chamber. Therefore, a rotary piston engine that exhibits excellent combustion performance can be realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

(Entire engine configuration)
1 and 2 show a rotary piston engine 1 (hereinafter simply referred to as engine 1) to which the fuel injection device of the present invention is applied.

  As shown in FIG. 1, the engine 1 is a two-rotor type including two rotors 2 and 2, and the two rotor housings 3 and 3 sandwich these intermediate housings 4 between them. The two side housings 5 and 5 are further integrated from both sides. In FIG. 1, a part of the right side is cut away to show the inside, and the left side housing 5 is also separated to show the inside. In addition, a symbol X in the figure is a rotation axis that is an axial center of the eccentric shaft 6.

  And the trochoid inner peripheral surfaces 3a and 3a drawn by parallel trochoid curves of the rotor housings 3 and 3, the inner surfaces 5a and 5a of the side housings 5 and 5 sandwiching the rotor housings 3 and 3 from both sides, and intermediate As shown in FIG. 2, two inner sides of the rotor accommodating chamber 7 having a substantially elliptical shape like a bowl when viewed from the direction of the rotation axis X are partitioned by the inner side surfaces 4 a and 4 a on both sides of the housing 4. Each of the rotors 2 is accommodated in each of the rotor accommodating chambers 7. The rotor accommodating chambers 7 and 7 are arranged symmetrically with respect to the intermediate housing 4 and have the same configuration except that the position and phase of the rotor 2 are different. The storage chamber 7 will be described.

  The rotor 2 is composed of a substantially triangular block body in which the central portion of each side bulges when viewed from the direction of the rotation axis X, and on the outer periphery thereof, there are three flank surfaces 2a having a substantially rectangular shape between the top portions. , 2a, 2a are provided. A recess 2b extending in the major axis direction is formed at the center of each flank surface 2a.

  Apex seals 16 are provided at the tops of the rotor 2. The apex seal 16 extends in the thickness direction of the rotor 2 and is formed of an elongated member having a length substantially the same as the thickness. The apex seal 16 is embedded through a spring 18 in a seal groove 17 provided at each top of the rotor 2. The spring 18 pushes the apex seal 16 outward in the radial direction. Each apex seal 16 is pressed against the trochoid inner peripheral surface 3a of the rotor housing 3 by centrifugal force when the rotor 2 rotates, and slides on the trochoid inner peripheral surface 3a (that is, moves while contacting). It is like that.

  Thus, the space between each top of the rotor 2 and the trochoid inner peripheral surface 3a of the rotor housing 3 is sealed, and the trochoid inner peripheral surface 3a of the rotor housing 3, the inner side surface 4a of the intermediate housing 4, and the side housing. Three working chambers 8, 8, 8 are defined in the interior of the rotor accommodating chamber 7 by the inner surface 5 a of the rotor 5 and the flank surface 2 a of the rotor 2.

  A phase gear (not shown) is provided inside the rotor 2. That is, the inner gear (rotor gear) on the inner side of the rotor 2 and the outer gear (fixed gear) on the side housing 5 side mesh with each other, and the rotor 2 is connected to the intermediate shaft 4 and the eccentric shaft 6 that penetrates the side housing 5. And is supported to make planetary rotation.

  That is, the rotational motion of the rotor 2 is defined by the meshing of the internal gear and the external gear, and the rotor 2 has an eccentric wheel of the eccentric shaft 6 while the three seal portions are in sliding contact with the trochoid inner peripheral surface 3a of the rotor housing 3, respectively. While rotating around 6a, it revolves around the rotation axis X in the same direction as rotation (this rotation and revolution are simply referred to as rotation of the rotor in a broad sense). Then, the three working chambers 8, 8, and 8 move in the circumferential direction while the rotor 2 makes one rotation, and intake, compression, expansion (combustion), and exhaust strokes are performed in each of them, and are generated thereby. A rotational force is output from the eccentric shaft 6 via the rotor 2.

  More specifically, in FIG. 2, the rotor 2 rotates clockwise as indicated by an arrow, and is on the left side of the rotor housing chamber 7 separated from the major axis Y of the rotor housing chamber 7 passing through the rotation axis X. Is generally the region for the intake and exhaust strokes, and the right side is generally the region for the compression and expansion strokes.

  When attention is paid to the upper left working chamber 8 in FIG. 2, this shows an intake stroke in which an air-fuel mixture is formed by the intake air and the injected fuel, and the working chamber 8 is compressed as the rotor 2 rotates. When shifting to the stroke, the air-fuel mixture is compressed inside. Thereafter, as in the working chamber 8 shown on the right side of FIG. 2, the ignition plugs 9 and 9 are ignited at a predetermined timing from the end of the compression stroke to the expansion stroke, and the combustion / expansion stroke is performed. When the exhaust stroke such as the lower working chamber 8 in FIG. 2 is finally reached, the combustion gas is exhausted from the exhaust port 10 and then returns to the intake stroke to repeat each stroke. . Since the fuel injection device of the present invention is directed to the intake stroke among the strokes, the working chamber 8 (hereinafter referred to as the intake working chamber 8) in the intake stroke will be described in more detail.

(Configuration of fuel injection device)
As described above, the intake working chamber 8 is formed on one end side (the upper side in FIG. 2) of the rotor housing chamber 7 in the major axis Y direction with the rotation of the rotor 2. An injector 15 (fuel injection valve) is arranged to inject fuel directly. The arrangement position of the injector 15 will be described later.

  As shown in FIGS. 1 and 2, the intake working chamber 8 communicates with a plurality of intake ports 11, 12, 13. That is, the first intake port 11 is opened near the short axis Z on the outer peripheral side of the rotor housing chamber 7 on the inner side surface 4 a of the intermediate housing 4 facing the intake working chamber 8. Further, the inner surface 5a of the side housing 5 facing the intake working chamber 8 is provided with the second intake port 12 and the second intake port 12 near the short axis Z on the outer peripheral side of the rotor accommodating chamber 7 so as to face the first intake port 11. The third intake port 13 is open.

  The intake ports 11, 12, 13 are opened to communicate with one end surface (left side surface in FIG. 2) in the minor axis Z direction of the intermediate housing 4 and the side housing 5, and each intake port 11, 12, An intake manifold 21 is connected to 13. The intake manifold 21 extends outward from the rotor housing 3 and extends further upward. The intake manifold 21 is connected to an intake pipe (not shown) to form an intake passage for intake air to the intake ports 11, 12, 13. ing.

  Similarly, the exhaust port 10 is also open to communicate with one end surface (left side surface in FIG. 2) in the short axis Z direction of the intermediate housing 4 and the side housing 5. An exhaust manifold 22 is connected. The exhaust manifold 22 is disposed below the intake manifold 21, extends outward from the rotor housing 3, extends leftward in FIG. 3 to be described later, and is connected to an exhaust pipe (not shown) to be connected to the exhaust port 10. An exhaust passage for exhausting the combustion gas exhausted from the outside is formed.

  Here, for example, in the low engine speed range of the engine 1, intake is performed only from the first intake port 11, and when the intake amount becomes insufficient, intake is also performed from the second intake port 12 (medium rotation range), and the intake amount is further increased. When it becomes insufficient, it is also drawn from the third intake port 13 (high rotation range), and maintains an optimum intake flow rate even if the intake amount changes, from low load low rotation to high load high rotation of the engine 1 It is designed to be able to intake air efficiently over the entire operating range.

  FIG. 3 is a view taken in the direction of arrow A in FIG. 2, showing a part of the configuration of the rotary piston engine 1 to which the fuel injection device of the present invention is applied. In FIG. 3, a part surrounded by a circle drawn with a virtual line is a partial cross-sectional view for easy viewing of the mounting structure of the injector 15.

  As shown in FIGS. 2 and 3, the injector 15 is disposed between the intake manifold 21 and the exhaust manifold 22 and closer to the trailing side than the intake port 11. The injector 15 is fixedly attached to the left side surface of the rotor housing 3 by a mounting bracket 24.

  The periphery of the injector 15 is covered with a shielding member 23 formed integrally with the intake manifold 21. Thus, by covering the periphery of the injector 15 with the shielding member 23, even if the exhaust manifold 22 through which high-temperature fuel gas flows is disposed below the injector 15, the radiant heat radiated from the exhaust manifold 22 is disposed. Is insulated by the shielding member 23, the injector 15 can be prevented from being affected by heat, and reliability can be ensured.

  The injection port of the injector 15 is formed so as to inject fuel toward the intake port 11. Specifically, a multi-hole type injection port in which a plurality of injection holes (not shown) for injecting fuel is formed is provided at the tip of the injector 15, and a wide angle capable of injecting fuel in a wide range is provided. It is formed into a type. Here, each nozzle hole can adjust the spray amount and spray direction by setting the nozzle hole diameter (cross-sectional area), its length and angle, so that the optimum fuel injection can be performed. A device is devised for the injection direction and the injection position of the nozzle hole.

  In addition to such a multi-hole type injector 15, a piezo injector that uses a piezo element that expands when a voltage is applied for valve control to increase responsiveness, thereby shortening the injection period and spraying. The particles may be further atomized.

  Thus, if the injector 15 is disposed on the trailing side of the intake port 11 and fuel is injected toward the intake port 11, the fuel injection timing can be made as early as possible. That is, by performing fuel injection at the timing when the intake working chamber 8 expands, it is possible to ensure as long as possible the time to vaporize and atomize the injected fuel and diffuse it uniformly into the intake working chamber 8. The rotary piston engine 1 that exhibits excellent combustion performance can be realized. Further, by injecting fuel toward the intake port 11, it is possible to efficiently use the kinetic energy of intake air and promote fuel diffusion.

  Here, the front end portion of the injector 15 is disposed to be inclined so as to be positioned substantially horizontally or below the rear end portion. In this way, the injected fuel will flow downward without accumulating in the injection port of the injector 15, and carbon deposits generated by burning the fuel with the high-temperature dilution gas will adhere around the injection port. Can be suppressed.

  The injector 15 is disposed between the intake manifold 21 and the exhaust manifold 22 on the inner side in the extending direction than both the manifolds 21 and 22. If the injector 15 is arranged in this way, when the intake manifold 21 and the exhaust manifold 22 are extended in the vehicle side surface direction, the intake manifold 21 and the exhaust manifold 22 are not subjected to external impacts in the event of a vehicle side collision. The injector 15 can be protected by relaxing, and safety can be ensured.

  Furthermore, in this embodiment, the penetration of the fuel injected from the injector 15 toward the intake port 11 is set to be shorter than the distance from the injection port to the trochoid inner peripheral surface 3a facing the injection direction in the intake working chamber 8. is doing. In this way, it is possible to suppress fuel adhesion to the trochoid inner peripheral surface 3a of the rotor housing 3, and to realize uniform fuel diffusion stably.

  The rotary piston engine 1 is provided with a lubrication device (not shown) for directly supplying oil (engine oil) for lubrication to a gas seal portion such as an apex seal 16 or a side seal (not shown). The oil sent out from the lubricating device is supplied into the intake working chamber 8 from the oil supply valve 25 facing the trochoid inner peripheral surface 3a of the rotor housing 3.

  The oil supply valve 25 is disposed on the leading side with respect to the injector 15 and on both sides of the rotor housing 3 in the rotor width direction (the engine longitudinal direction) and substantially in the center in the rotor width direction.

(About fuel injection timing)
Next, the fuel injection timing of the injector 15 for efficiently diffusing the fuel injected from the injector 15 will be described. Specifically, the fuel injection timing is set within a period in which the intake air flow velocity in the first half of the intake stroke is equal to or greater than a predetermined value so that the diffusibility of fuel by intake air is optimal. In other words, the fuel injection timing is set within a period centering on the timing when the intake working chamber 8 becomes -150 ° after the bottom dead center at the eccentric angle (−150 ° ABDC (After Bottom Dead Center)). Yes.

  The eccentric angle referred to here is based on a state (bottom dead center: BDC) in which the top of the rotor 2 is located at the lower end and the volume of the intake working chamber 8 is maximized, as indicated by a virtual line in FIG. (0 ° ABDC), and the rotational angle of the eccentric shaft 6 toward the rotational direction. As shown by the solid line, the state in which the rotor 2 returns about 80 ° in the reverse direction corresponds to −150 ° ABDC. Yes.

  The graph of FIG. 4 shows the result of comparing the kinetic energy of the intake air in the intake working chamber 8 in the range of −210 ° to −60 ° ABDC in the intake stroke. As shown in this graph, it can be seen that the kinetic energy of the intake air is large at the peak of −150 ° ABDC, the flow velocity of the intake air is large, and a vigorous flow of the intake air flow is formed. Therefore, if fuel is injected in the range of -170 ° to -130 ° ABDC, more preferably in the range of -160 ° to -140 ° ABDC, centering on -150 ° ABDC in the first half of the intake stroke, fuel can be efficiently used. Can be diffused.

  In this way, the diffusion of fuel can be promoted by efficiently using the kinetic energy of the intake air. Furthermore, fuel injection can be performed at the timing when the intake working chamber 8 expands, fuel adhesion to the inner peripheral surface of the rotor housing 3 can be suppressed, and uniform fuel diffusion can be realized stably.

  The fuel injection timing may be set so as to promote fuel vaporization and atomization using the dilution gas generated in the exhaust stroke. That is, if the fuel is injected by the injector 15 before the temperature in the intake working chamber 8 is lowered by the air sucked from the intake port 11, the air flows from the working chamber 8 on the exhaust side to the intake working chamber 8. The injected fuel is instantly vaporized and atomized by the heat of the dilution gas, which is advantageous in forming a uniform air-fuel mixture in the working chamber 8.

  As described above, when the fuel supply device of the present invention is applied to a rotary piston engine, the injector 15 is disposed on the trailing side of the intake port 11 and fuel is injected toward the intake port 11. Therefore, the fuel injection timing can be made as early as possible. That is, by performing fuel injection at the timing when the intake working chamber 8 expands, it is possible to ensure as long as possible the time to vaporize and atomize the injected fuel, and to diffuse it uniformly into the working chamber 8; A rotary piston engine that exhibits excellent combustion performance can be realized. Further, by injecting fuel toward the intake port 11, it is possible to efficiently use the kinetic energy of intake air and promote fuel diffusion.

  In addition, the structure of this invention is not limited to the thing of the said embodiment, Other various structures are included. That is, in the above embodiment, the two-rotor type engine 1 is shown, but the present invention is not limited to this. Further, the number of intake ports is not limited to three and may be two.

  As described above, the present invention can provide a fuel injection device for a rotary piston engine that can accelerate fuel atomization, vaporization, and atomization by making fuel injection timing as early as possible. Since a highly practical effect can be obtained, it is extremely useful and has high industrial applicability.

1 is a perspective view showing an outline of a rotary piston engine according to an embodiment of the present invention. It is sectional drawing which simplified one part which shows the principal part of the same engine. It is A arrow line view in FIG. 2 which shows the structure of the same engine. It is a graph which shows the relationship between the temperature in an intake operation chamber, and the injection timing of fuel.

DESCRIPTION OF SYMBOLS 1 Rotary piston engine 3 Rotor housing 3a Trocoid inner peripheral surface 8 Working chamber (intake working chamber)
10 Exhaust port 11 Intake port 15 Injector (fuel injection valve)
21 Intake manifold 22 Exhaust manifold 23 Shielding member

Claims (5)

A fuel injection device of the rotary piston engine having a rotary shaft is housed in the rotor housing so as to extend in the horizontal direction the rotor, and a fuel injection valve for injecting fuel directly into the working chamber in the intake stroke,
An intake manifold connected to the intake port and extending outward of the rotor housing;
The fuel injection valve is disposed on the trailing side of the intake port facing the working chamber and below the intake manifold ,
The fuel injection device for a rotary piston engine, wherein an injection port of the fuel injection valve is formed to inject fuel toward the intake port. In claim 1,
The penetration of fuel injected toward the intake port is set to be shorter than the distance from the injection port of the fuel injection valve to the inner peripheral surface facing the injection direction in the working chamber. A fuel injection device for a rotary piston engine. In claim 1 or 2 ,
Before SL fuel injection valve, fuel injection device of the rotary piston engine, characterized in that the periphery of that is covered by the shielding member. In any one of claims 1 to 3 ,
A fuel injection device for a rotary piston engine, wherein a front end portion of the fuel injection valve is disposed so as to be substantially horizontal or below a rear end portion. In any one of claims 1 to 4 ,
Is connected before Symbol exhaust port, an exhaust manifold that extends into the rotor housing outer together is disposed below the intake manifold,
The fuel for the rotary piston engine is characterized in that the fuel injection valve is disposed between the intake manifold and the exhaust manifold and on the inner side in the extending direction than the end portions on the extending side of both manifolds. Injection device.

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