JP2010248981A - Rotary piston engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary piston engine capable of improving combustion speed by forming homogeneous air-fuel mixture distribution in a combustion chamber immediately before ignition even if the operating state of the engine is varied and an intake air flow state is significantly changed. <P>SOLUTION: The rotary piston engine 1 includes a fuel injection valve 15 directly injecting fuel from a plurality of nozzle ports 15a into an intake operating chamber 8 in an intake stroke. Some of the plurality of nozzle ports 15a inject fuel toward intake ports 11, 12, 13 (intake port injection S1), and the remaining nozzle ports 15a inject fuel toward a plurality of small chambers 17a, 17b, 17c to 17h in a recess 2b formed at the flank face 2a of the rotor 2 (recess injection S2). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a direct injection type rotary piston engine, and more particularly to a technique for improving a combustion speed.

Conventionally, in a rotary piston engine, it is known that the mixture distribution in the combustion chamber just before ignition tends to be rich on the trailing side and lean on the leading side. In such a mixture distribution, a relatively rich mixture exists in the quench zone where the distance between the rotor flank surface and the rotor housing is narrow, and conversely a relatively lean mixture exists in the vicinity of the spark plug. There is a problem that it tends to cause poor combustion.

In order to solve this problem, it has been proposed that combustion stability is improved by performing stratified combustion by concentrating fuel in the vicinity of the spark plug at the time of ignition. For example, in Patent Document 1, fuel spray is ignited by injecting fuel along a flow of 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. What is concentrated near the plug is disclosed.
JP-A-6-288249

  On the other hand, from a different point of view, the fuel injected from the fuel injection valve collides with the intake air flow introduced into the working chamber from the intake port to promote the agitation of the fuel and air. Attempts have also been made to improve the combustion rate by forming a homogeneous mixture distribution in the combustion chamber.

  However, in this case, since the intake air flow in the working chamber in the intake stroke of the rotary piston engine varies greatly depending on the operating state of the engine, the operation of forming a homogeneous mixture distribution in the combustion chamber just before ignition is stably obtained. It ’s difficult.

  The present invention has been made in view of such a point, and the object of the present invention is to provide a homogeneous combustion chamber just before ignition even when the operating state of the engine fluctuates and the flow state of intake air changes greatly. Another object of the present invention is to provide a rotary piston engine having an improved combustion speed by forming a uniform air-fuel mixture distribution.

  A first configuration related to the present invention is a rotary piston engine provided with a fuel injection valve for directly injecting fuel from a plurality of injection holes into a working chamber in an intake stroke, and a recess is provided in a flank surface of the rotor. The recess is divided into a plurality of small chambers, and at least some of the plurality of nozzle holes have fuel injected into the working chamber in the intake stroke colliding with at least one inner wall of the small chamber. It is provided to do.

  In the first configuration, the fuel injected toward the small chamber in the intake stroke is trapped in the recess. The fuel trapped in the recess is vaporized until it is ignited by the spark plug in the latter half of the compression stroke, and the mixture distribution in the combustion chamber just before ignition is homogenized. Therefore, according to this configuration, even when the operating state of the engine fluctuates and the intake flow changes, the combustion speed can be improved by forming a homogeneous mixture distribution in the combustion chamber just before ignition. .

  In the second configuration according to the present invention, the number of the small chambers in the working chamber in the intake stroke is the same as the number of injection holes that can inject fuel toward the small chamber in the working chamber in the intake stroke. It is characterized by being set.

  In the second configuration, the number of small chambers in the working chamber in the intake stroke and the number of injection holes that can inject fuel toward the small chamber in the working chamber in the intake stroke are set to be the same. For one small chamber, fuel injection from one of the nozzle holes that can inject fuel toward the small chamber becomes possible, and fuel concentrates in a specific small chamber and becomes a liquid pool. In addition to being able to be suppressed, a uniform fuel trap can be formed throughout the plurality of small chambers. Therefore, according to this configuration, the fuel vaporization until the ignition by the spark plug in the latter half of the compression stroke is promoted by the uniform fuel trap, and the mixture distribution in the combustion chamber just before ignition is homogenized, and the combustion speed is increased. Can be improved.

  According to a third configuration of the present invention, among the plurality of nozzle holes provided in the fuel injection valve, the nozzle holes other than the nozzle holes capable of injecting fuel toward the small chamber in the working chamber in the intake stroke are: It is provided so that fuel can be injected toward the intake port.

  According to the third configuration, since the fuel can be reliably collided with the intake air introduced from the intake port into the working chamber in the intake stroke, the intake air and the fuel are not attached to the wall surface of the rotor housing or the like. The combustion rate can be improved by promoting the stirring.

  A fourth configuration according to the present invention is characterized in that the plurality of small chambers are divided and formed by disposing ribs extending in the rotor width direction and the axial direction in the recess. .

  According to the fourth configuration, since it is only necessary to dispose the rib in the recess of the conventional structure, it is possible to minimize the cost generated when the present invention is applied.

  According to the present invention, even when the operating state of the engine fluctuates and the flow state of the intake air changes greatly, the combustion speed is improved by forming a homogeneous mixture distribution in the combustion chamber just before ignition. be able to.

  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.

(Configuration of the whole engine)
1 and 2 show a rotary piston engine 1 (hereinafter simply referred to as an engine 1) to which 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 3 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 part of each side bulges when viewed from the direction of the rotation axis X, and on the outer periphery thereof, there are three substantially rectangular flank surfaces 2a, 2a, 2a are provided. A recess 2b extending in the major axis direction is formed at the center of each flank surface 2a. The specific shape of the recess 2b will be described later.

  The rotor 2 has a seal portion (not shown) at each top portion, and these seal portions are in sliding contact with the trochoid inner peripheral surface 3a of the rotor housing 3, and the trochoid inner peripheral surface 3a of the rotor housing 3 and intermediate Three working chambers 8, 8, 8 are defined in the interior of the rotor accommodating chamber 7 by the inner surface 4 a of the housing 4, the inner surface 5 a of the side housing 5, and the flank surface 2 a of the rotor 2.

  A phase gear is provided inside the rotor 2 (not shown). That is, the internal gear (rotor gear) on the inner side of the rotor 2 and the external 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.

  In other words, the rotational motion of the rotor 2 is defined by the meshing of the internal gear and the external gear. 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, 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 shifts to a compression stroke as the rotor 2 rotates. Then, the air-fuel mixture is compressed inside. Thereafter, as in the working chamber 8 shown on the right side of the figure, the ignition plugs 9 and 9 are ignited at predetermined timings from the end of the compression stroke to the expansion stroke, and the combustion / expansion stroke is performed. Finally, when the exhaust stroke such as the working chamber 8 on the lower left side of the figure is reached, the combustion gas is exhausted from the exhaust port 10 and then returns to the intake stroke to repeat each stroke. Since the present invention targets the intake stroke among the above-mentioned strokes, the working chamber 8 (hereinafter referred to as the intake working chamber 8) in the intake stroke will be described in more detail.

  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. A fuel injection valve 15 is arranged to inject fuel directly.

A plurality of intake ports 11, 12, 13 communicate with the intake working chamber 8. 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, as shown in FIG. 1, the inner surface 5 a of the side housing 5 facing the intake working chamber 8 is close to 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 second intake port 12 and the third intake port 13 are open.

  Thus, for example, in the low rotation 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 region), and further the intake amount When the air intake becomes insufficient, the air is also drawn from the third intake port 13 (high rotation range), and the optimum intake flow rate is maintained even if the intake air amount changes, so that the engine 1 is driven at a low load to a high load at a high speed. Efficient intake can be achieved over the entire operating range.

However, when the intake air amount, the intake air direction, etc. change greatly depending on the operating state of the engine 1 in this way, the flow state in the intake working chamber 8 also changes greatly, and this change can be handled only by fuel injection by the fuel injection valve 15. It is very difficult to do.
Therefore, in the present embodiment according to the present invention, the rib 16 is disposed in the recess 2b to divide the recess 2b into a plurality of small chambers (here, eight), and the fuel is supplied to the plurality of small chambers 17a, 17b, 17c,. The fuel injection valve 15 is provided with injection holes that can inject toward 17h and the intake ports 11, 12, and 13.

(Specific shape of recess)
As shown in FIGS. 1 and 3, the recess 2 b itself has the same structure as the conventional structure (a structure in which both ends in the rotor rotation direction and the side surface in the rotor axial direction become wider as the rotor flank faces). By disposing one rib 16 in the rotor rotation direction and three ribs 16 in the rotor axial direction in the recess 2b, the recess 2b has a plurality of (here, eight) small chambers 17a, 17b, 17c,... 17h. It is divided into At this time, the rib 16 is disposed in the recess 2b so that the shape and volume of each chamber are substantially equal.

(Fuel injection valve)
On the other hand, the fuel injection valve 15 is a multi-hole type having a plurality of injection holes 15a for injecting fuel to the tip, and in this embodiment, as shown in FIG. 4, twelve injection holes 15a. There is. Each nozzle hole 15a can adjust the spray amount and the spray direction by setting the nozzle hole diameter (cross-sectional area), its length, and angle, and these nozzle holes can be used for optimal fuel injection. The device is devised for the injection direction and the injection position.

(Injection direction of nozzle hole)
Next, the injection position of each nozzle hole 15a will be described. As shown in FIG. 2, some of the fuel injected from the fuel injection valve 15 is in the intake ports 11, 12, 13, and the small chambers 17 a, 17 b, 17 c,. Each injection hole 15a is provided in the fuel injection valve so that the fuel injection valve can be injected.

  Here, the fuel injected from the fuel injection valve 15 toward the intake port is collected, and the fuel injected toward the plurality of small chambers 17a, 17b, 17c... 17h in the intake port injection S1 and the recess 2b is collected. This is referred to as recess injection S2 (FIGS. 2 and 4).

FIG. 4 shows the tip of the fuel injection valve 15. The fuel injection valve 15 has a total of 12 injection holes, and has 4 injection holes 12a capable of intake port injection S1 and 8 injection holes 12a capable of recess injection S2. Moreover, in this embodiment, the reason why the number of nozzle holes capable of the recess injection S2 is set to eight is to make the number the same as the number of the small chambers.

(Injection position of nozzle hole)
Next, the injection positions of the intake injection S1 and the recess injection S2 will be described. In the present embodiment, the injection position of the intake port injection S1 is changed in accordance with the change in the engine speed.

That is, the engine 1 is inhaled only from the first intake port in the low rotation range, and is also sucked in from the second intake port 12 in the mid rotation range, and all the intake ports 11, 12, 13 are in the high rotation range. Everything is inhaled.
For this reason, the intake port injection S1 is performed toward the intake ports 11, 12, and 13 that are actually inhaling into the intake working chamber 8 (for example, toward the first intake port 11 in the low rotation range). Only fuel injection). By doing so, the fuel can reliably collide with the air introduced into the intake working chamber 8 from the intake ports 11, 12, and 13 without adhering to the intake port or the like.

By setting the injection position of the intake injection S1 as described above, the fuel can be reliably collided with the intake air introduced from the intake ports 11, 12, 13 into the working chamber 8 in the intake stroke. The combustion speed can be improved by promoting the stirring of the intake air and the fuel without adhering the fuel to the wall surface of the rotor housing or the like.

  Next, the injection position of the recess injection S2 will be described. FIG. 5 shows the recess injection S2 from the fuel injection valve 15 toward the plurality of small chambers 17a, 17b, 17c... 17h.

  As shown in FIG. 5, the fuel injected from the fuel injection valve 15 toward the plurality of small chambers 17a, 17b, 17c... 17h is one injection hole 15a for one small chamber (for example, 17a). Only fuel from is injected. By doing so, it is possible to suppress the fuel from concentrating into a specific chamber (for example, 17b) and becoming a liquid pool, and to promote fuel vaporization until it is ignited by the spark plugs 9 and 9 in the latter half of the compression stroke. .

  In the present embodiment, the number of small chambers 17a, 17b, 17c... 17h and the number of injection holes 15a capable of injecting fuel toward the small chambers are set to the same number. It is possible to make a fuel trap.

  Therefore, by setting the injection position of the recess injection S2 as described above, it is possible to prevent the fuel from concentrating into a specific small chamber (for example, 17b) and to become a liquid pool, and to form a plurality of small chambers 17a, 17b, 17c. ... A uniform fuel trap can be formed over the entire 17h. The fuel vaporization until ignition by the spark plugs 9, 9 in the latter half of the compression stroke is promoted by the uniform fuel trap, and the mixture distribution in the combustion chamber just before ignition is homogenized to improve the combustion speed. be able to.

  As described above, when the present invention is applied to a rotary piston engine, even if the operating state of the engine fluctuates and the flow state of intake air changes greatly, a uniform fuel trap can be performed over the entire small chamber. The fuel vaporization is promoted and the mixture distribution in the combustion chamber just before ignition can be homogenized, so that the combustion rate can be improved.

In addition, the structure of this invention is not limited to the thing of the said embodiment, Other various structures are included. For example, in the recess 2b, the side surfaces of the rotor rotational direction and the axial end as shown in FIG. 4 do not have an angle from the normal line of the flank surface 2a. It can be configured to include. Further, the small chambers 17a, 17b,... 17h can be configured so that the rib 16 has an angle from the rotor rotation axis direction or the rotor rotation axis direction, as shown in FIG. Moreover, although the two-rotor type engine 1 is shown in the embodiment, the present invention is not limited to this. Further, the number of intake ports is not limited to three and may be two. The plurality of injection holes 15 a of the fuel injection valve 15 can be arranged on the long axis Y line of the rotor accommodating chamber 7 or in the vicinity thereof away from the intake ports 11, 12, 13.

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 the perspective view which showed the detail of the rotor which concerns on embodiment of this invention. It is a schematic diagram of the nozzle hole of an injector. It is the schematic diagram which showed recess injection. It is the perspective view which showed the detail of the rotor which concerns on embodiment other than this embodiment. It is the perspective view which showed the detail of the rotor which concerns on embodiment other than this embodiment.

DESCRIPTION OF SYMBOLS 1 Rotary piston engine 2 Rotor 2a Frank surface 2b Recess 3 Rotor housing 4 Intermediate housing 5 Side housing 7 Rotor accommodating chamber 8 Working chamber (intake working chamber)
11 First intake port 12 Second intake port 13 Third intake port 15 Fuel injection valve 15a Injection hole
16 Rib X Rotation axis Y Long axis Z Short axis

Claims (4)

A rotary piston engine having a fuel injection valve that directly injects fuel from a plurality of injection holes into a working chamber in an intake stroke, wherein a recess is formed in a flank surface of the rotor, and the recess is divided into a plurality of small chambers. And
At least some of the plurality of nozzle holes are provided so that fuel injected into the working chamber in the intake stroke collides with at least one inner wall of the small chamber. Rotary piston engine. 2. The rotary piston engine according to claim 1, wherein the number of the small chambers and the number of nozzle holes capable of injecting fuel toward the small chambers in the working chamber in the intake stroke are set to be the same.   Of the plurality of injection holes provided in the fuel injection valve, the injection holes other than the injection holes capable of injecting fuel toward the small chamber in the working chamber in the intake stroke can inject fuel toward the intake port. The rotary piston engine according to claim 1, wherein the rotary piston engine is provided. The rotary piston according to any one of claims 1 to 3, wherein the plurality of small chambers are dividedly formed by disposing ribs extending in a rotor width direction and an axial direction in the recess. engine.