JP5544970B2 - Rotary piston engine - Google Patents

Description

  The present invention belongs to a technical field related to a rotary piston engine.

  Generally, a rotary piston engine has a generally triangular shape in a rotor housing chamber formed by arranging side housings on both sides of a rotor housing having a substantially elliptical trochoid inner circumferential surface defined by a major axis and a minor axis orthogonal to each other. It is an engine that houses a rotor of a shape. In this rotary piston engine, each of the three working chambers defined between the outer peripheral surface of the rotor and the inner peripheral surface of the rotor housing is moved in the circumferential direction as the rotor rotates, and the intake, compression, expansion, and exhaust in each working chamber. Let each step be performed in turn.

In such a rotary piston engine, a first spark plug is usually provided on the leading side (advance side) in the rotor rotation direction with respect to the short axis of the rotor housing, and the trailing side (in the rotor rotation direction with respect to the short axis) ( A second spark plug is provided on the delay side. Recesses are respectively formed on the outer peripheral surfaces of the rotor that are in contact with the working chambers (see, for example, Patent Document 1).
Further, in Patent Document 1, the flow passage in the recess is changed in the recess, and a flow changing means for generating turbulent flow is provided in the combustion chamber adjacent to the recess, thereby promoting combustion in the entire combustion chamber. I try to plan.

JP 2008-185027 A

  By the way, on the leading side in the rotor rotation direction with respect to the short axis of the recess in the compression top, the distance between the rotor outer peripheral surface and the rotor housing inner peripheral surface becomes longer toward the leading side. In the expansion stroke, the flow velocity of the squish flow flowing from the trailing side to the leading side in the recess becomes slow and the pressure decreases in the expansion stroke. Tend to be worse. Particularly, the combustibility on the leading side becomes worse at light loads.

  However, the flow changing means of Patent Document 1 changes the flow of air flow generated relative to the rotor by the rotation of the rotor, and promotes combustion on the trailing side rather than the leading side. Is. Moreover, in Patent Document 1, when the first spark plug is ignited, the flow changing means may be located at a position facing the first spark plug. In this case, the flow changing means is used to ignite the first spark plug. There is a problem in that the flammability on the leading side is deteriorated by adversely affecting the propagation of the weak flame immediately after.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a first spark plug provided on the leading side in the rotor rotation direction with respect to the short axis of the rotor housing, and the short shaft. Further, in a rotary piston engine provided with a second spark plug provided on the trailing side in the rotor rotation direction, flame propagation (leading side combustibility) due to ignition of the first spark plug is to be improved. There is.

In order to achieve the above object, according to the present invention, a rotor housing having a substantially elliptical trochoidal inner peripheral surface defined by a long axis and a short axis perpendicular to each other, and both sides of the rotor housing are arranged. And a side housing that forms a rotor housing chamber together with the rotor housing, and is housed in the rotor housing chamber, divides three working chambers in the rotor housing chamber, and moves each working chamber in the circumferential direction by rotation. However, in each working chamber, a rotor that sequentially performs intake, compression, expansion, and exhaust strokes, a first spark plug that is provided on the leading side in the rotor rotation direction with respect to the short shaft of the rotor housing, and the short shaft And a second spark plug provided on the trailing side in the rotor rotation direction, and is in contact with each working chamber of the rotor. For the rotary piston engine in which recesses are respectively formed on the outer peripheral surface, the recess is located on the leading side in the rotor rotational direction from the short axis of the recess in the compression top, and the expansion stroke after the compression top And a turbulent flow generating member that converts at least a part of the squish flow flowing from the trailing side to the leading side in the recess into turbulent flow, and the rotor rotation direction relative to the short axis of the recess in the compression top No turbulent flow generating member is provided on the trailing side of the turbulent flow generating member, and the turbulent flow generating member transmits the flame due to the ignition in the recess facing the first spark plug at the time of ignition of the first spark plug. promotes and provided at a position aggravate the propagation of the flame of the trailing side by the ignition of the second spark plug, The first spark plug is located on the rotor width direction center line, and the turbulence generating member is provided on both sides of the rotor width direction center line and at a position deviating from the rotor width direction center line. It was configured to be.

  With the above configuration, mixing of the air-fuel mixture is improved on the leading side of the turbulent flow generation member due to the turbulent flow generated by the turbulent flow generation member. Further, the turbulent flow generation member promotes the propagation of flame by ignition of the first spark plug in the recess, that is, a growth space in which a weak flame immediately after ignition of the first spark plug grows and propagates. Since the flame that has continued and grown on the leading side of the growth space is formed at a position where a promotion space that promotes propagation by turbulence is formed, the flame is generated by the turbulent flow generation member in these growth and promotion spaces. Therefore, the weak flame immediately after ignition of the first spark plug propagates smoothly while growing, and the grown flame promotes propagation by turbulent flow. As a result, in combination with the mixing of the air-fuel mixture, the flame propagation property (leading side combustibility) due to ignition of the first spark plug is improved.

  Further, since the turbulent flow generation member becomes a resistance element against the squish flow from the trailing side, it plays a role of weakening the squish flow itself, and thereby, flame propagation by ignition of the second spark plug (on the trailing side) (Flammability) deteriorates. Here, on the trailing side, the distance between the rotor outer peripheral surface and the rotor housing inner peripheral surface becomes shorter as going to the leading side, so that heat is easily transferred to the rotor housing. It is preferable to suppress combustion on the trailing side. In the present invention, as described above, the squish flow itself is weakened by the turbulent flow generation member, and the combustibility on the trailing side is deteriorated, so that heat loss on the trailing side can be reduced.

In addition, a growth space in which a weak flame immediately after ignition of the first spark plug propagates while growing is required on the center line in the rotor width direction in the recess, but the turbulence generating member deviates from the center line in the rotor width direction. It is possible to secure such a growth space. As a result, a weak flame immediately after ignition of the first spark plug propagates smoothly while growing in this growth space. Then, in the accelerating space, the turbulent flow generated by the turbulent flow generating member promotes propagation of the grown flame to the rotor width direction and the leading side, thereby improving the combustibility on the leading side.

  In the rotary piston engine, the turbulent flow generation member is preferably formed integrally with the recess.

  Thus, the turbulent flow generating member can be easily formed in the recess, and the cost for manufacturing the rotor can be reduced.

  As described above, according to the rotary piston engine of the present invention, the combustion on the leading side can be promoted by the turbulent flow generating member, the combustibility on the leading side can be improved, and the heat loss on the trailing side can be improved. Therefore, fuel consumption can be improved.

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 the one part which shows the principal part of a rotary piston engine. It is the figure which looked at one flank surface of the rotor from the front. It is the IV-IV sectional view taken on the line of FIG. It is a graph which shows the relationship between the rotation angle from the compression top of an eccentric shaft, and the heat release rate when only a 1st spark plug is ignited in the case where a turbulent flow generation member is provided in a recess. It is a graph which shows the relationship between the rotation angle from the compression top of an eccentric shaft, and the heat release rate when only a 2nd spark plug is ignited in the case where a turbulent flow generation member is provided in a recess. It is a simulation result which shows a mode that a flame spreads when a turbulent flow generation member is provided in a recess, (a) shows a case where a rotation angle from a compression top of an eccentric shaft is 15 degrees, (b), The case where the rotation angle is 20 ° is shown. It is a simulation result which shows a mode that a flame spreads when not providing a turbulent flow generation member in a recess, (a) shows a case where a rotation angle from a compression top of an eccentric shaft is 15 degrees, (b), The case where the rotation angle is 20 ° is shown.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 and 2 show a rotary piston engine 1 (hereinafter simply referred to as an engine 1) according to an embodiment of the present invention. The engine 1 is a two-rotor type (two-cylinder engine) having two rotors 2, and two rotor housings 3 on the front side (right side in FIG. 1) and the rear side (left side in FIG. 1) are intermediate. In a state where the housing 4 (corresponding to the side housing) is sandwiched between the two, the housing 4 is integrated by being further sandwiched between the two side housings 5 from both sides. In FIG. 1, a part of the right side (front side) is cut away to show the inside, and the left side (rear side) side housing 5 is also separated to show the inside. Reference numeral X in the figure denotes a rotational axis of the eccentric shaft 6 serving as an output shaft, which is hereinafter simply referred to as a rotational axis X.

  The rotor housing 3 has a trochoid inner peripheral surface 3a drawn by a parallel trochoid curve, an inner side surface 5a of the side housing 5 sandwiching the rotor housing 3 from both sides, and side surfaces 4a on both sides of the intermediate housing 4 as shown in FIG. As shown in FIG. 2, the rotor accommodating chamber has a substantially elliptical shape (a substantially elliptical shape defined by a major axis Y and a minor axis Z orthogonal to each other (see FIG. 2)) as viewed from the direction of the rotation axis X. 7 (cylinder) is divided side by side on the front side and the rear side, and one rotor 2 is accommodated in each of the rotor accommodating chambers 7. Each rotor accommodating chamber 7 is arranged symmetrically with respect to the intermediate housing 4 and has the same configuration except that the position and phase of the rotor 2 are different. Will be described.

  The rotor 2 is composed of a substantially triangular block body in which the central part of each side bulges outward as viewed from the direction of the rotational axis X, and three substantially rectangular flank is provided between the apexes on the outer peripheral surface thereof. A surface 2a (an outer peripheral surface in contact with each working chamber 8 described later) is provided. Recesses 2b are formed at the center of each flank surface 2a.

  The rotor 2 has apex seals (not shown) at the apexes of the triangles. The apex seals are in sliding contact with the trochoid inner peripheral surface 3a of the rotor housing 3, and the rotor housing 3 has a trochoid inner peripheral surface 3a. The inner side surface 4a of the intermediate housing 4, the inner side surface 5a of the side housing 5, and the flank surface 2a of the rotor 2, the interior of the rotor accommodating chamber 7 (the flank surface 2a of the rotor 2 and the inner trochoidal surface of the rotor housing 3) 3), three working chambers 8 are respectively defined.

  Although illustration is omitted, the rotor 2 includes the intermediate housing 4 and the side housing 5 while the internal gear (rotor gear) provided inside the rotor 2 meshes with the external gear (fixed gear) provided on the side housing 5. Is supported so as to make a planetary rotational movement.

  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 apex seals 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 the rotation (including rotation and revolution, simply referred to as rotation of the rotor 2). Then, the three working chambers 8 move in the circumferential direction while the rotor 2 makes one rotation, and intake, compression, expansion, and exhaust strokes are performed in each of them, and the rotational force generated thereby is transmitted through the rotor 2. And output from the eccentric shaft 6. In addition, during one rotation of the rotor 2, the eccentric shaft 6 rotates three times, and during this time, the three working chambers 8 each perform a combustion cycle once. For this reason, one combustion cycle is performed for one rotation of the eccentric shaft 6.

  More specifically, in FIG. 2, the rotor 2 rotates in the clockwise direction as indicated by an arrow, and the rotor accommodating chamber 7 is separated by the long axis Y of the rotor accommodating chamber 7 passing through the rotation axis X. The left side of FIG. 2 is generally an intake and exhaust stroke region, and the right side is a compression and expansion stroke region.

  When attention is paid to the upper left working chamber 8 in FIG. 2, the working chamber 8 is in an intake stroke in which an air-fuel mixture is formed by intake air and injected fuel, and the working chamber 8 in the intake stroke is the rotor 2. When the compression stroke is shifted as the engine rotates, the air-fuel mixture is compressed therein. Thereafter, as in the working chamber 8 shown on the right side of FIG. 2 (in FIG. 2, this working chamber 8 is in the compression top (compression top dead center: TDC)), a predetermined period from the latter stage of the compression stroke to the expansion stroke is obtained. It is ignited by first and second spark plugs 21 and 22 described later at the timing, and an expansion stroke is performed. When the exhaust stroke such as the lower left 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 the above steps. .

  An injector 15 (fuel injection valve) is attached on the long axis Y of the rotor housing 3. The injector 15 is disposed facing the working chamber 8 in the intake stroke, and directly injects fuel into the working chamber 8.

  A plurality (three in this embodiment) of intake ports 11, 12, and 13 communicate with the working chamber 8 in the intake stroke. That is, the first intake port 11 is opened on the side surface 4 a of the intermediate housing 4 facing the working chamber 8 near the short axis Z on the outer peripheral side of the rotor housing chamber 7. Further, as shown in FIG. 1, the inner surface 5a of the side housing 5 facing the working chamber 8 in the intake stroke is short on the outer peripheral side of the rotor accommodating chamber 7 so as to face the first intake port 11. Near the axis Z, the second intake port 12 and the third intake port 13 are opened.

  For example, in the low rotation range of the engine 1, the intake air is sucked only from the first intake port 11, and when the intake amount becomes insufficient, the second intake port 12 also intakes (medium rotation region), and the intake amount is insufficient. Then, the intake air is also taken from the third intake port 13 (high rotation range), and the optimum intake flow velocity is maintained even if the intake air amount changes, and from the low load low rotation to the high load high rotation of the engine 1 Intake can be efficiently performed over the entire operation range.

  In the rotor housing 3, the first spark plug 21 and the leading side (advance side) and the trailing side (delay side) of the rotor rotation direction across the short axis Z (near the short axis Z) are respectively A second spark plug 22 is attached. These two spark plugs 21 and 22 are used for the first spark plug 21 and the second spark plug 22 to burn the air-fuel mixture in the working chamber 8 in the compression or expansion stroke (the air-fuel mixture compressed in the compression stroke). Ignite in order. In this embodiment, both spark plugs 21 and 22 are ignited before the compression top (TDC).

  As shown in FIG. 2, the first spark plug 21 faces the leading side portion of the recess 2b in the compression top (TDC) in the rotor rotation direction with respect to the short axis Z, and the second spark plug 22 It faces the trailing side portion of the rotor rotation direction from the short axis Z of 2b. Thus, the recess 2b has a length longer than the distance between the spark plugs 21 and 22. Further, both the spark plugs 21 and 22 are located on the center line L in the width direction of the rotor 2 (see FIG. 3). The center line L in the width direction of the rotor 2 coincides with the center line in the width direction of the recess 2b.

  A plurality (two in this embodiment) of exhaust ports 10 communicate with the working chamber 8 in the exhaust stroke. That is, one exhaust port 10 is opened near the short axis Z on the outer peripheral side of the rotor housing chamber 7 on the side surface 4 a of the intermediate housing 4 facing the working chamber 8. As shown in FIG. 1, another exhaust port 10 is opened on the inner surface 5 a of the side housing 5 facing the working chamber 8 in the exhaust stroke so as to face the exhaust port 10. Thus, the engine 1 employs a so-called side exhaust system, and the opening position and shape of the exhaust port 10 are set so that the intake open timing and the exhaust open timing do not overlap. Yes. As a result, the residual exhaust gas brought into the next stroke is reduced, and as a result, the combustion stability is improved even when the air-fuel mixture is lean.

  As shown in FIG. 3 and FIG. 4, the recess 2 b is positioned on the leading side in the rotor rotation direction with respect to the short axis Z of the recess 2 b in the compression top (TDC), and in the expansion stroke after the compression top. There are provided two plate-like turbulent flow generating members 51 for converting at least a part of the squish flow W flowing from the trailing side to the leading side in the recess 2b into turbulent flow.

  These two turbulent flow generation members 51 promote the propagation of flame due to ignition of the first spark plug 21 in the recess 2b facing the first spark plug 21 at the time of ignition of the first spark plug 21. That is, a growth space in which a weak flame immediately after ignition of the first spark plug grows and propagates, and an acceleration space that is continuous on the leading side of the growth space and that promotes propagation by turbulent flow are formed. It is provided at a position. In the present embodiment, the turbulent flow generating members 51 are provided on both sides of the center line L in the width direction of the rotor 2, and the rotational direction of the first spark plug 21 and the rotor 2 in the recess 2 b in the compression top (TDC). At approximately the same position. That is, on the center line L in the width direction of the rotor 2 in the recess 2b, a growth space in which a weak flame immediately after ignition of the first spark plug 21 grows and propagates is required. Such a growth space is ensured between the two turbulent flow generation members 51 by being provided on both sides of the center line L in the width direction of the rotor 2 (both sides of the first spark plug 21). Further, the turbulent flow generation member 51 is located at a position where it does not enter the promotion space formed on the leading side of the growth space (a position where the propagation of the flame is not hindered).

  The turbulent flow generation member 51 protrudes in a triangular shape from the bottom surface of the recess 2b in a state where the turbulent flow generation member 51 is inclined toward the leading side and away from the center line L in the width direction of the rotor 2. In this embodiment, the turbulent flow generation member 51 is integrally formed on the bottom surface of the recess 2b. The greater the inclination angle and height of the turbulent flow generating member 51 with respect to the center line L (the distance between the top of the turbulent flow generating member 51 and the bottom surface of the recess 2b), the stronger the turbulent flow is generated. If it is too strong, it will adversely affect the weak flame immediately after ignition of the first spark plug. Therefore, the inclination angle and height are set in consideration of this and promotion of combustion. Note that it is difficult to make the height larger than the depth of the recess 2b. From the viewpoint of generating turbulent flow in the recess 2b, a predetermined value (considering an error) than the depth of the recess 2b. It is preferable that the turbulent flow generating member 51 be small by a value that does not reliably protrude from the recess 2b.

  The squish flow W colliding with the turbulent flow generating member 51 from the trailing side tends to get over the turbulent flow generating member 51. This squish flow W is converted into turbulent flow in the vicinity of the leading side of the apex of the triangle of the turbulent flow generation member 51. Thereby, mixing of the air-fuel mixture is improved on the leading side of the turbulent flow generation member 51. Further, the turbulent flow generating member 51 is provided at a position in the recess 2b that promotes the propagation of flame due to the ignition of the first spark plug 21, that is, at positions on both sides of the center line L in the width direction of the rotor 2. Space and the above-mentioned promotion space are secured. As a result, the weak flame immediately after ignition of the first spark plug 21 propagates smoothly while growing in the growth space, and the grown flame is caused by the turbulent flow generated by the turbulent flow generation member 51 in the promotion space. Propagation in the rotor width direction and the leading side is promoted. As a result, combined with the mixing of the air-fuel mixture, flame propagation (leading side combustibility) due to ignition of the first spark plug 21 is improved.

  Further, since the turbulent flow generation member 51 becomes a resistance element against the squish flow W from the trailing side, it plays a role of weakening the squish flow W itself. The trailing side flammability) deteriorates. Thereby, the heat loss on the trailing side can be reduced. That is, on the trailing side, the distance between the flank surface 2a and the trochoid inner peripheral surface 3a of the rotor housing 3 becomes shorter as going to the leading side. Even if combustion on the side is promoted, heat loss is increased. However, as in this embodiment, the distance between the flank surface 2a and the trochoid inner peripheral surface 3a of the rotor housing 3 increases as going to the leading side, while promoting combustion on the leading side, By suppressing the combustion at, the heat loss can be reduced and the fuel consumption can be improved.

  FIG. 5 shows the rotational angle θ (deg) from the compression top of the eccentric shaft 6 when only the first spark plug 21 is ignited with and without the turbulent flow generation member 51 as described above. It is a graph which shows the relationship with heat release rate dQ / d (theta) (J / deg). As can be seen from the portion surrounded by the broken line in FIG. 5, more heat is generated at an earlier timing when the turbulent flow generation member 51 is provided. This is because the combustion on the leading side is promoted by providing the turbulent flow generation member 51.

  Further, FIG. 6 shows the rotation angle θ (deg) from the compression top of the eccentric shaft 6 when only the second spark plug 22 is ignited in the case where the turbulent flow generation member 51 is not provided. ) And the heat generation rate dQ / dθ (J / deg). As can be seen from FIG. 6, the rise of the heat generation rate is slower when the turbulent flow generation member 51 is provided. This is because the combustion on the trailing side is suppressed by providing the turbulent flow generation member 51.

  FIG. 7 is a simulation result showing how the flame spreads (propagates) when the turbulent flow generation member 51 as described above is provided. FIG. 7A shows the rotational angle of the eccentric shaft 6 from the compression top of 15. A case of (°) is shown, and (b) shows a case where the rotation angle is 20 °. From FIG. 7, the flame grown in the growth space between the two turbulent flow generating members 51 spreads on both sides in the width direction of the rotor 2 and on the leading side in the promotion space that continues to the leading side of the growth space. I understand.

  On the other hand, FIG. 8 is a simulation result showing how the flame spreads (propagates) when the turbulent flow generation member 51 is not provided. FIG. 8A shows the rotational angle of the eccentric shaft 6 from the compression top at 15 °. A case is shown, and (b) shows a case where the rotation angle is 20 °. Compared with FIG. 7B and FIG. 8B, as can be seen from the portions (three places) surrounded by the broken line in FIG. 7B, the case where the turbulent flow generation member 51 is provided is The flame is greatly spread on both sides in the width direction of the rotor 2 and the leading side, and the propagation of the flame is promoted by the turbulent flow generation member 51. Therefore, the combustibility on the leading side is improved.

  The present invention is not limited to the embodiment described above, and can be substituted without departing from the spirit of the claims.

For example, in the above embodiment, the turbulent flow generation member 51 is formed in a triangular shape, but may be formed in any shape as long as at least a part of the squish flow W can be converted into turbulent flow. .

  The present invention includes a first spark plug provided on the leading side in the rotor rotational direction from the short shaft of the rotor housing, and a second spark plug provided on the trailing side in the rotor rotational direction from the short shaft. This is useful for rotary piston engines.

DESCRIPTION OF SYMBOLS 1 Rotary piston engine 2 Rotor 2b Recess 3 Rotor housing 3a Trochoid inner peripheral surface 4 Intermediate housing (side housing)
5 Side housing 7 Rotor storage chamber (cylinder)
8 Working chamber 21 First spark plug 22 Second spark plug 51 Turbulence generating member L Rotor width direction center line Y Long axis Z Short axis

Claims (2)

A rotor housing having a substantially elliptical trochoid inner peripheral surface defined by a major axis and a minor axis orthogonal to each other, and sides arranged on both sides of the rotor housing to form a rotor accommodating chamber together with the rotor housing The housing is housed in the rotor housing chamber, and three working chambers are defined in the rotor housing chamber, and each working chamber is moved in the circumferential direction by rotation, and intake, compression, expansion, and exhaust are performed in each working chamber. And a first spark plug provided on the leading side in the rotor rotational direction with respect to the short axis of the rotor housing, and provided on the trailing side in the rotor rotational direction with respect to the short axis. And a second spark plug, wherein the rotor has a recess formed on an outer peripheral surface thereof in contact with each working chamber. A re-piston engine,
The recess is located on the leading side in the rotor rotational direction from the short axis of the recess in the compression top, and at least of the squish flow flowing from the trailing side to the leading side in the recess in the expansion stroke after the compression top. A turbulent flow generating member that converts a part into turbulent flow is provided, and a turbulent flow generating member is not provided on the trailing side in the rotor rotation direction from the short axis of the recess in the compression top,
The turbulent flow generating member promotes the propagation of flame due to the ignition in the recess facing the first spark plug at the time of ignition of the first spark plug, and the trailing flame by the ignition of the second spark plug It provided the propagation in a position worsen,
The first spark plug is located on the center line in the rotor width direction,
Further, the turbulent flow generating member is provided on both sides of the rotor width direction center line and at positions deviating from the rotor width direction center line . In the rotary piston engine of claim 1 Symbol placement,
The rotary piston engine, wherein the turbulent flow generation member is integrally formed with the recess.