JP2010156287A - Fuel injection device of rotary piston engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve combustion characteristics of a rotary piston engine 1. <P>SOLUTION: The rotary piston engine 1 is constituted by housing a nearly triangular rotor 2 which partitions the rotor holding chamber 31 into three working chambers 8 and which performs each of the strokes of intake, compression, expansion, and exhaust in order while moving each of the working chambers 8 circumferentially by making planetary rotational movements about an output shaft X. The rotary piston engine 1 is provided with a first fuel injection valve 15 and a second fuel injection valve 16. The first fuel injection valve 15 is attached to a rotary housing 3 so that it borders the working chamber 8 which is in an intake stroke, and directly injects fuel into the working chamber 8 which is in an intake stroke. The second fuel injection valve 16 is attached to the rotary housing 3 so that it borders the working chamber 8 which is in a compression stroke, and directly injects fuel into the working chamber 8 which is in a compression stroke. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The technology disclosed herein generally relates to a fuel injection device for a rotary piston engine.

  The rotary piston engine is an engine in which a substantially triangular rotor is accommodated in a rotor accommodating chamber formed by disposing side housings on both sides of a rotor housing having a substantially elliptical trochoid inner peripheral surface. As the rotor rotates, the rotary piston engine causes each of the three working chambers partitioned between the rotor and the housing to move in the circumferential direction, and sequentially performs intake, compression, expansion, and exhaust strokes (for example, Patent Documents). 1).

  The fuel supply in such a rotary piston engine is generally carried out by injecting fuel from a fuel injection valve attached to an intake port and / or an intake manifold, and this makes it possible to homogenize the air-fuel mixture. ing.

Further, in Patent Document 1, in order to form a stratified mixture around the spark plug, the fuel injection valve disposed near the major axis so as to face the working chamber in the intake stroke is directed toward the spark plug. Thus, a rotary piston engine in which fuel is directly injected into a working chamber is also disclosed.
JP-A-6-288249

  By the way, the conventional rotary piston engine has a problem that the combustion efficiency is relatively poor. The present applicant has found that this problem is caused by the fact that the combustion pattern of the conventional rotary piston engine has two-stage combustion characteristics including main combustion and late combustion.

  In other words, the rotary piston engine has a feature that the working chamber in the compression or expansion stroke (hereinafter, the working chamber in this state is also referred to as a compression / expansion working chamber) has a flat shape extending in the rotation direction of the rotor. However, as described above, even when the air-fuel mixture is formed relatively homogeneously by fuel injection at the intake port or the like, when moving from the intake stroke to the compression stroke as the rotor rotates, The flow of the air-fuel mixture (fuel) is relatively delayed with respect to the rotation of the rotor, and as a result, in the compression / expansion operation chamber having a flat shape in the rotation direction of the rotor, the region on the relatively advanced side in the rotor rotation direction Becomes lean, and inhomogeneity occurs such that the region on the delay side in the rotor rotation direction becomes relatively rich.

  On the other hand, the flame generated by the ignition of the spark plug disposed facing the compression / expansion working chamber easily propagates to the advance side in the rotor rotation direction, that is, the relatively lean side due to the flow in the working chamber. On the other hand, it is difficult to propagate to the lag side of the rotor rotation direction, which is relatively rich.

  Combining the heterogeneity of the air-fuel mixture in the compression / expansion operation chamber and the flame propagation characteristics unique to the rotary piston engine, the combustion pattern of the rotary piston engine is relatively advanced on the advancing side in the rotor rotation direction. After the main combustion occurs on the lean side, the two-stage combustion characteristic occurs in which the late combustion occurs on the relatively rich side that is delayed in the rotor rotation direction.

  The fuel injection device for a rotary piston engine disclosed herein aims to improve the combustion characteristics of the rotary piston engine.

  The applicant of the present application pays attention to the point of eliminating the heterogeneity of the air-fuel mixture in the compression / expansion working chamber when improving the combustion characteristics of the rotary piston engine, and has a configuration in which fuel is directly injected into the working chamber in the compression stroke. Adopted.

  That is, as described above, the heterogeneity of the air-fuel mixture in the compression / expansion operation chamber becomes more conspicuous with the rotation of the rotor, so that while directly injecting fuel into the operation chamber in the intake stroke, By injecting the fuel again into the working chamber at the timing when the chamber shifts to the compression stroke, the air-fuel mixture in the compression / expansion working chamber can be effectively homogenized.

  A fuel injection device for a rotary piston engine includes a rotor housing having a substantially elliptical trochoidal inner peripheral surface defined by a long axis and a short axis orthogonal to each other, and a long axis and a short axis sandwiching the rotor housing, respectively. Three working chambers are partitioned between a side housing that forms a rotor accommodating chamber together with the rotor housing and the rotor housing chamber that is accommodated in the rotor accommodating chamber by being arranged on both sides in the orthogonal output shaft direction. And a substantially triangular rotor that sequentially performs intake, compression, expansion, and exhaust strokes while moving each working chamber in the circumferential direction by rotating around the output shaft. Attached to the rotor housing so as to face the working chamber in the stroke, and A first fuel injection valve that directly injects fuel into a working chamber in the air stroke; and a fuel that is attached to the rotor housing so as to face the working chamber in the compression stroke and directly injects the fuel into the working chamber in the compression stroke And a second fuel injection valve.

  When the first fuel injection valve directly injects the fuel into the working chamber in the intake stroke, the fuel wall surface adhesion can be suppressed. Further, since the fuel is injected at a timing much earlier than the ignition timing, the vaporization atomization time can be secured for a long time. This is advantageous in forming an air-fuel mixture with good vaporization atomization. Furthermore, an improvement in filling efficiency by intake air cooling can be expected.

  The air-fuel mixture supplied with fuel through the first fuel injection valve shifts from the intake stroke to the compression stroke with the rotation of the rotor, and accordingly, the relatively delayed side of the rotation direction in the working chamber becomes rich, Heterogenization occurs so that the leading side in the rotational direction becomes lean. The second fuel injection valve injects fuel into the working chamber during the compression stroke. This fuel injection relatively enriches the lean region. As a result, the heterogeneity of the air-fuel mixture can be eliminated.

  This elimination of the heterogeneity of the air-fuel mixture can improve the combustion characteristics of the rotary piston engine. Improved combustion characteristics can improve fuel economy.

  The rotary piston engine communicates with the working chamber in the intake stroke so that air can be sucked into the working chamber, and an intake port that opens to at least one of the side housings, and the compression Or at least one spark plug attached to the rotor housing so as to face the working chamber in the expansion stroke, and each of the first and second fuel injection valves is disposed near a major axis of the rotor housing. When the first fuel injection valve is viewed in the output shaft direction, the fuel is injected in the direction of the intake port, and the second fuel injection valve is viewed in the output shaft direction. Alternatively, fuel may be injected in the direction of the spark plug.

  Since the first fuel injection valve injects the fuel from the vicinity of the long axis of the rotor housing toward the intake port, the spray flight distance becomes relatively long, which is advantageous in suppressing the fuel wall surface adhesion.

  Since the second fuel injection valve injects fuel from the vicinity of the long axis of the rotor housing toward the spark plug, the fuel is supplied to the region on the advance side in the rotational direction of the rotor in the working chamber in the compression stroke. This is advantageous. That is, by supplying fuel to a relatively lean area, the area can be enriched, which is effective in eliminating the heterogeneity of the air-fuel mixture in the working chamber.

  The first and second fuel injection valves are configured to divide and inject fuel supplied to the working chamber, and a fuel injection amount of the second fuel injection valve is determined by a fuel injection amount of the first fuel injection valve. It may be less than the amount.

  Since the fuel supplied into the working chamber by the second fuel injection valve is supplied at the timing of the compression stroke, the vaporization atomization time becomes relatively short. Therefore, on the assumption that the first and second fuel injection valves perform split injection of fuel, the fuel injection amount of the second fuel injection valve is made relatively small, and the fuel injection amount of the first fuel injection valve is made relatively large. By doing so, the disadvantage that vaporization atomization time cannot be secured is minimized while suppressing deterioration of fuel consumption. That is, it is advantageous in that the unburned mixture does not increase and the increase in HC can be suppressed.

  In other words, most of the fuel supplied into the working chamber is supplied by the first fuel injection unit during the intake stroke, so that a long vaporization atomization time is ensured and the mixture is homogenized. Will be advantageous.

  The first and second fuel injection valves are arranged such that the first fuel injection valve is on the delay side in the rotation direction of the rotor and the second fuel injection valve is on the advance side in the rotation direction of the rotor. It is good also as arrange | positioning along with the rotation direction.

  The first fuel injection valve that injects fuel into the working chamber in the intake stroke is arranged on the delay side in the rotational direction of the rotor, in other words, on the side relatively close to the working chamber in the intake stroke, while in the compression stroke By arranging the second fuel injection valve for injecting fuel into a working chamber on the leading side in the rotational direction of the rotor, in other words, on the side relatively close to the working chamber in the compression stroke, From the target relationship, the period in which the first fuel injection valve faces the working chamber in the intake stroke and the period in which the second fuel injection valve faces the working chamber in the compression stroke become longer. This increases the degree of freedom in the timing of fuel injection by the first and second fuel injection valves. Accordingly, the first fuel injection valve ensures the vaporization atomization time by injecting fuel at a relatively early timing, for example, while the second fuel injection valve injects fuel at, for example, a relatively late timing. Thus, it is possible to reliably ensure the homogenization of the air-fuel mixture immediately before ignition.

  In contrast, in the first and second fuel injection valves, the first fuel injection valve is on the advance side in the rotation direction of the rotor, and the second fuel injection valve is on the delay side in the rotation direction of the rotor. It is good also as arrange | positioning along with the rotation direction of the said rotor.

  The first fuel injection valve for injecting fuel into the working chamber in the intake stroke is arranged on the advance side in the rotational direction of the rotor, in other words, on the side relatively close to the working chamber in the compression stroke. By arranging the second fuel injection valve for injecting fuel into a certain working chamber on the delay side in the rotation direction of the rotor, in other words, on the side relatively close to the working chamber in the intake stroke, the first and second The spray flight distance of the fuel injection unit can be increased. This is advantageous in suppressing the adhesion of the fuel to the wall surface, and as a result, the fuel consumption and emission can be improved.

  The first and second fuel injection valves may be respectively disposed on both sides of the rotor rotation direction across a long axis of the rotor housing. This arrangement is the most desirable arrangement for arranging the first and second fuel injection valves side by side in the rotation direction of the rotor.

  The rotor housing and the rotor are arranged in a plurality in the output shaft direction with the side housing interposed therebetween, and the first and second fuel injection valves are attached to each of the plurality of rotor housings, The first and second fuel injection valves are provided so as to extend over the plurality of rotor housings so as to connect the first and second fuel injection valves and supply fuel to the first and second fuel injection valves of the respective rotor housings. A pressure accumulator including a fuel supply pipe and a second fuel supply pipe may be further provided, and the first fuel supply pipe and the second fuel supply pipe may be communicated with each other at a substantially central position in the length direction. .

  In other words, the first and the second provided in each rotor accommodating chamber can be obtained by simply attaching a pressure accumulator including the first and second fuel supply pipes to a rotary piston engine having a plurality of rotor accommodating chambers arranged in the output shaft direction. Fuel supply to each of the two fuel injection valves can be realized. That is, it is advantageous in simplifying and downsizing the fuel supply structure.

  As described above, the fuel injection device for the rotary piston engine directly injects fuel into the working chamber in which the first fuel injection valve is in the intake stroke, thereby reducing the vaporization atomization time while suppressing the fuel wall surface adhesion. While the fuel can be secured for a long time, the fuel injection valve injects fuel into the working chamber in the compression stroke, so that the lean region in the working chamber becomes relatively rich and the mixture becomes inhomogeneous. Can be eliminated. As a result, the combustion characteristics of the rotary piston engine can be improved, and fuel consumption can be improved.

  Hereinafter, a fuel injection device for a rotary piston engine will be described with reference to the drawings. In addition, the following description is only an illustration essentially and does not intend restrict | limiting an application thing or a use.

  1 and 2 show an example of a rotary piston engine 1 (hereinafter also simply referred to as engine 1). The engine 1 is of a two-rotor type having two rotors 2 and 2, and the two rotor housings 3 and 3 on the front side and the rear side sandwich an intermediate housing (side housing) 4 therebetween. These are integrated by being sandwiched between two side housings 5 and 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. In addition, a symbol X in the figure is a rotation axis (output shaft) 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, inner side 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, the rotor accommodating chamber 31 having a substantially elliptical shape as a ridge as seen from the direction of the rotation axis X has two front side and rear side two inner side surfaces 4 a and 4 a on both sides of the housing 4. One rotor 2 is accommodated in each of the rotor accommodating chambers 31. Each rotor accommodating chamber 31 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. Therefore, hereinafter, one rotor accommodating chamber 31 is provided. Will be described.

  The rotor 2 is formed 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 three substantially rectangular flank surfaces 2a, 2a are formed on the outer periphery between the top portions. , 2a. A recess 2b extending in the major axis direction is formed at the center of each flank surface 2a.

  The rotor 2 has apex seals (not shown) at the respective tops, and these apex seals 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 the intermediate housing 4 The inner side surface 4a, the inner side surface 5a of the side housing 5, and the flank surface 2a of the rotor 2 define three working chambers 8, 8, and 8 inside the rotor accommodating chamber 31, respectively. Therefore, the engine 1 has a total of six working chambers, ie, first to third three working chambers 8 on the front side and fourth to sixth three working chambers 8 on the rear side ( (See FIG. 7).

  A phase gear is provided inside the rotor 2 (not shown). That is, the internal gear (rotor gear) inside the rotor 2 and the external gear (fixed gear) on the side housing 5 mesh with each other, and the rotor 2 is connected to the eccentric shaft 6 that penetrates the intermediate housing 4 and the side housing 5. On the other hand, it is supported to make a 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. (Eccentric shaft) Revolving around the rotation axis X in the same direction as the rotation while rotating around the eccentric shaft 6a (including rotation and revolution, simply referred to as rotation of the rotor). 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 the left side of the rotor storage chamber 31 is separated by the long axis Y of the rotor storage chamber 31 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 (hereinafter, the working chamber in this state is referred to as the intake working chamber 8). When the working chamber 8 shifts to the compression stroke as the rotor 2 rotates, the air-fuel mixture is compressed therein (not shown, but hereinafter, the working chamber in this state is referred to as the compression working chamber 8). Say). Thereafter, as in the working chamber 8 shown on the right side of FIG. 2, the ignition plugs 91 and 92 are ignited at a predetermined timing from the final stage of the compression stroke to the expansion stroke, and the combustion / expansion stroke is performed (hereinafter referred to as this state). A working chamber is also referred to as a compression / expansion working chamber 8). Then, when the exhaust stroke such as the lower left working chamber 8 in FIG. 2 is reached (hereinafter, the working chamber in this state is also referred to as the exhaust working chamber 8), after the combustion gas is exhausted from the exhaust port 10, Returning to the intake stroke again, each stroke is repeated.

  A plurality of intake ports 11, 12, 13 communicate with the intake working chamber 8. That is, the first intake port 11 is opened on the inner side surface 4 a of the intermediate housing 4 facing the intake working chamber 8 near the short axis Z on the outer peripheral side of the rotor accommodating chamber 31. Further, as shown in FIG. 1, the inner side 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 31 so as to face the first intake port 11. The second intake port 12 and the third intake port 13 are open. 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 range), and the intake amount is further 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 amount changes, and the entire operation from the low load low rotation to the high load high rotation of the engine 1 is maintained. The air can be efficiently sucked in across the area.

  A plurality of exhaust ports 10 and 10 communicate with the exhaust working chamber 8. That is, the exhaust port 10 is opened on the inner side surface 4 a of the intermediate housing 4 facing the exhaust working chamber 8 near the short axis Z on the outer peripheral side of the rotor accommodating chamber 31. As shown in FIG. 1, the exhaust port 10 is also opened on the inner surface 5 a of the side housing 5 facing the exhaust working chamber 8 so as to face the exhaust port 10. As described above, the engine 1 employs a so-called side exhaust system, and the opening position and the opening shape of the exhaust port 10 are set so that the intake open timing and the exhaust open timing do not overlap. . 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. Therefore, in this engine 1, the air-fuel ratio of the air-fuel mixture is made to be the stoichiometric air-fuel ratio.

  A first injector (fuel injection valve) 15 and a second injector 16 are attached near the top of the rotor housing 3 corresponding to the long axis Y of the rotor housing 3. The first injector 15 is disposed facing the intake working chamber 8, and the second injector 16 is disposed facing the compression working chamber 8.

  As shown in FIGS. 2 and 3, the first injector 15 is arranged on the delay side in the rotor rotation direction with respect to the long axis Y, that is, on the left side in FIG. 3. The first injector 15 is configured to inject fuel directly into the intake working chamber 8, and the first injector 15, particularly when viewed in the direction of the rotation axis X shown in FIG. Fuel is injected from the vicinity of the top toward the intake ports 11, 12, 13. The first injector 15 is a multi-hole type having a plurality of injection holes for injecting fuel at the tip thereof. Here, as shown in FIG. 4, the first injector 15 has a total of eight directions (D1-1, D1-2, D2-1, D2) including four directions in the rotor rotation direction and two directions in the rotor width direction. Eight injection holes are formed so as to inject fuel into (-2, D3-1, D3-2, D4-1, D4-2). The number of nozzle holes of the first injector 15 is not limited to this. FIG. 4 shows the spray positions of the fuel injected from the injectors 15 and 16 on a virtual plane that is separated from the tip positions of the first and second injectors 15 and 16 by a predetermined distance. Double circles indicate the axial positions of the first and second injectors 15 and 16 projected onto the virtual plane, respectively. In addition, the injection direction of the 1st injector 15 shown to FIG.3, 4 is an illustration, and is not limited to this.

  As shown in FIGS. 2 and 3, the second injector 16 is disposed on the leading side in the rotor rotation direction with respect to the long axis Y, that is, on the right side in FIG. 3. The second injector 16 is configured to directly inject fuel into the compression working chamber 8, and the second injector 16 is particularly designed to be disposed in the rotor housing 3 when viewed in the direction of the rotation axis X shown in FIG. Fuel is injected from the vicinity of the top toward a spark plug 91 described later. Similarly to the first injector 15, the second injector 16 is a multi-hole type having a plurality of injection holes for injecting fuel at the tip thereof. Here, the second injector 16 is, as shown in FIG. Two injection holes are formed so as to inject fuel in one direction with respect to the rotor rotation direction and in two directions with respect to the width direction of the rotor. By injecting fuel in two directions with respect to the width direction of the rotor, it is possible to avoid spraying directly on the plug hole of the spark plug 91. In addition, the injection direction of the 2nd injector 16 shown to FIG.3, 4 is an illustration, and is not limited to this. Here, the first and second injectors 15 and 16 may employ the same injector as the main body, but may be different from each other only in the plate on which the nozzle hole attached to the tip is formed.

  As shown in FIG. 3, the first and second injectors 15 and 16 are respectively attached to the rotor housing 3 so that the axial directions thereof are parallel to each other. Here, in FIG. 3, the axial centers of the first and second injectors 15 and 16 are arranged so as to have a predetermined angle with respect to the long axis Y, but the first and second injectors are arranged. The angle at which 15 and 16 are disposed is not particularly limited. The arrangement angle of the first and second injectors 15 and 16 may be set as appropriate so that the angle formed between the direction of the fuel injected from the tip and the axis is optimum. Although not shown, first and second injectors 15 and 16 are provided for each of the two rotor housing chambers 31 on the front side and the rear side. The first and second injectors 15 and 16 are disposed so as to be parallel to each other. Therefore, in this engine 1, as shown in FIG. 5, a total of four injectors 15 and 16 are arranged so as to be parallel to each other. In FIG. 5, the illustration of the side housings 5 and 5 in the engine 1 is omitted.

  As shown in FIGS. 3 and 5, the injectors 15 and 16 are connected to the accumulator 7, and the accumulator 7 is connected to a high-pressure fuel pump (not shown). The accumulator 7 stores the fuel supplied from the high-pressure fuel pump in a high-pressure state so that the fuel can be supplied to the injectors 15 and 16 at an arbitrary timing. The pressure accumulator 7 includes a first fuel supply pipe 71 and a second fuel supply pipe 72. The first fuel supply pipe 71 includes a first injector 15 attached to the front rotor housing 3 (right rotor housing 3 in FIG. 5) and a rear rotor housing 3 (left rotor housing 3 in FIG. 5). Rotation axis X direction (precisely, a direction inclined by a predetermined angle with respect to the rotation axis X) across the front and rear rotor housings 3 so as to communicate with the second injector 16 attached to each other It is arrange | positioned so that it may extend. The second fuel supply pipe 72 has a front side and a rear side so that the second injector 16 attached to the front rotor housing 3 and the first injector 15 attached to the rear rotor housing 3 communicate with each other. Is disposed so as to extend in the direction of the rotation axis X (more precisely, a direction inclined by a predetermined angle on the opposite side of the rotation axis X from the first fuel supply pipe 71). ing. The first and second fuel supply pipes 71 and 72 intersect at a substantially central position in the length direction, and communicate with each other at the intersecting position. Thus, the pressure accumulator 7 is configured to have an X shape when viewed in plan view.

  In this configuration, the distances between the four injectors 15 and 16 through the fuel supply pipes 71 and 72 can be made substantially equal to each other. This is effective in suppressing variations in fuel injection amount errors in the injectors 15 and 16. That is, when fuel is injected from a certain injector 15, 16, the pulsation accompanying the fuel injection propagates through the fuel supply pipes 71, 72 and reaches the other injectors 15, 16. The transmission of pulsation may affect the fuel injection of the injectors 15 and 16. For example, when the distance between the injectors 15 and 16 is different, the influence of pulsation is relatively large between the injectors 15 and 16 having a relatively short distance, and between the injectors 15 and 16 having a relatively long distance. The influence of pulsation becomes relatively small. The magnitude of the influence of such pulsation causes the magnitude of the error in the fuel injection amount in each of the injectors 15 and 16. On the other hand, when the distances between the injectors 15 and 16 are made equal, the influences of pulsation become equal to each other, so that the fuel injection amount errors in the injectors 15 and 16 become equal. That is, variation in fuel injection amount error in each of the injectors 15 and 16 is suppressed.

  As shown in FIG. 3, each of the first and second fuel supply pipes 71 and 72 protrudes downward at both ends, and is connected to the upper ends of the first or second injectors 15 and 16. 73. As described above, since the four injectors 15 and 16 are arranged in parallel to each other, the connecting portions 73 and the injectors 15 and 16 are aligned, and the connecting portions 73 are connected to the injectors 15 and 16. If the pressure accumulator 7 is pushed in so as to be fitted on the upper end of the injector, all of the injectors 15 and 16 can be connected to the pressure accumulator 7 at a time. The pressure accumulator 7 is separately fixed to the rotor housing 3. Thus, the structure which integrated the 1st and 2nd fuel supply pipes 71 and 72 is effective in simplifying the structure of the pressure accumulator 7, making it easy to assemble.

  One end (the right end in FIG. 5) of the first fuel supply pipe 71 is closed, while the other end (the left end in FIG. 5) is opened for drilling when the pressure accumulator 7 is manufactured. A blind plug 74 is attached to the opening to ensure airtightness and liquid tightness. One end (the right end in FIG. 5) of the second fuel supply pipe 72 is also closed, while the other end (the left end in FIG. 5) is opened for drilling, and this opening has a high-pressure fuel pump. An end portion 75 of the connecting pipe connected to is attached.

  In the pressure accumulator 7, a fuel pressure sensor 76 is attached at a position where the first and second fuel supply pipes 72 intersect. The fuel pressure sensor 76 measures the fuel pressure in the accumulator 7, and outputs the measurement signal to a control unit 100 (hereinafter abbreviated as ECU) described later (see FIG. 6). The ECU 100 uses the fuel pressure signal when setting the pulse width (fuel injection signal) to be supplied to the injectors 15 and 16. In this configuration, the distance between the fuel pressure sensor 76 and each of the injectors 15 and 16 is substantially equal to each other. This suppresses variations in the injectors 15 and 16 with respect to the measured value of the fuel pressure sensor 76.

  Although not shown in the drawings, in the pressure accumulator 7 having the above-described configuration, the fuel pressure sensor 76 is not attached to the intersection of the first and second fuel supply pipes 71 and 72 but is attached to the other end of the first fuel supply pipe 71. A fuel pressure sensor 76 may be attached. This configuration has the advantage of minimizing the seal portion in the accumulator 7.

  As shown in FIG. 2, at the side of the rotor housing 3, the trailing side (delay side) position and the leading side (advance side) position in the rotor rotation direction across the short axis Z are respectively T-side ignition. A plug 91 and an L-side spark plug 92 are attached. These two spark plugs 91 and 92 face the compression / expansion working chamber 8 and ignite the air-fuel mixture in the compression / expansion working chamber 8 simultaneously or sequentially with a phase difference. By providing the two spark plugs 91 and 92 in this manner, the combustion speed is increased in the compression / expansion working chamber 8 having a flat shape.

  FIG. 6 shows a configuration related to the control of the rotary piston engine 1. The ECU 100 controls the operation of the first and second injectors 15 and 16, the ignition circuits of the T-side and L-side spark plugs 91 and 92, the motor of the throttle valve 107, and the like. For this ECU 100, at least an air flow sensor 105 for detecting the intake flow rate taken into the intake passage, a linear O2 sensor 106 for detecting the oxygen concentration in the exhaust, and an eccentric angle sensor for detecting the rotational angle of the eccentric shaft 6. 103, a water temperature sensor 104 that detects a temperature state of the cooling water (engine water temperature), an accelerator opening sensor 101, an engine speed sensor 102, and a fuel pressure sensor 76 each output a signal. The ECU 100 determines the operating state of the engine 1, and according to the operating state, the opening of the throttle valve 107, the ignition timing by the T-side and L-side spark plugs 91 and 92 in each working chamber 8, the first The fuel injection amount and fuel injection timing are controlled by the second injectors 15 and 16.

  The fuel amount injected from the first and second injectors 15 and 16 will be described. The first and second injectors 15 and 16 are configured to divide and inject fuel supplied into the working chamber 8. That is, the total amount of fuel injected by the first injector 15 and the amount of fuel injected by the second injector 16 is equal to the amount of fuel to be supplied into the working chamber 8. Thus, on the premise that fuel is divided and injected by the first and second injectors 15 and 16, the fuel injection amount of the first injector 15 is set relatively large, and the fuel injection amount of the second injector 16 is set relatively small. The

  Next, fuel injection control in the rotary piston engine 1 configured as described above will be described with reference to the timing chart of FIG. As shown in FIG. 3, the first injector 15 injects fuel from the vicinity of the top of the rotor housing 3 toward the intake ports 11, 12, 13 in the intake working chamber 8. For this reason, the fuel injection by the first injector 15 may be referred to as intake counter-injection. The fuel injection timing of the first injector 15 is based on the state (compression top dead center: TDC) in which the rotor 2 is in the state shown in FIG. 1 and the volume of the compression / expansion working chamber 8 is minimized (0 °). , The rotational angle (eccentric angle) on the rotational direction side of the eccentric shaft 6 is set within the range of −450 ° to −330 ° ATDC. The rotation angle of the rotor 2 at this time is indicated by a two-dot chain line in FIG. This fuel injection timing is a timing at which the kinetic energy of the intake air in the intake working chamber 8 is large and the intake air flow velocity is also large, and intense intake flow is formed in the intake working chamber 8. For this reason, the fuel can be efficiently diffused by injecting the fuel toward the intake ports 11, 12, and 13 at this timing. Further, since this timing is significantly earlier than TDC, it is possible to ensure a long vaporization atomization time. In this way, a relatively large amount of fuel is efficiently diffused by the intake air opposed injection by the first injector 15, and an air-fuel mixture with good vaporization atomization is formed by securing a long vaporization atomization time. Thereafter, the working chamber 8 shifts to the compression stroke.

  In addition, the direct injection of fuel into the intake working chamber 8 can obtain the effect of improving the charging efficiency by intake air cooling, and in addition to the case of port injection that injects fuel into the intake port, etc. Since adhesion to the wall surface is suppressed, it is advantageous in terms of improvement in fuel consumption and emission.

  On the other hand, the second injector 16 injects fuel from the top position of the rotor housing 3 toward the spark plug 91 in the compression working chamber 8. For this reason, fuel injection by the second injector 16 may be referred to as compression injection. The fuel injection timing of the second injector 16 is set within a range of −180 ° to −150 ° ATDC. The rotation angle of the rotor 2 at this time is indicated by a solid line in FIG. 3, which corresponds to the middle stage of the compression stroke. As described above, as the working chamber 8 shifts from the intake stroke to the compression stroke, the flow of the air-fuel mixture (fuel) is relatively delayed with respect to the rotation of the rotor 2. As a result, in the compression / expansion working chamber 8. Causes an inhomogeneity such that the region on the advance side in the rotor rotation direction becomes lean and the region on the delay side in the rotor rotation direction becomes rich. On the other hand, as shown by a thick solid line in FIG. 3, the fuel is injected by the second injector 16 in the direction of the spark plug 91, so that the inside of the compression working chamber 8 is related to the rotation angle of the rotor 2. The fuel can be supplied to a relatively lean area. As a result, the lean region in the compression working chamber 8 and the subsequent compression / expansion working chamber 8 is enriched, and the heterogeneity of the air-fuel mixture with respect to the rotor rotation direction can be eliminated. Thus, with the air-fuel mixture homogenized, the two ignition plugs 91 and 92 on the T side and the L side ignite at a predetermined timing, simultaneously or in the order of the leading side and the trailing side.

  In addition, since the fuel injection timing of the second injector 16 is a relatively late timing, it is difficult to sufficiently secure the vaporization atomization time. However, since the amount of fuel injected by the second injector 16 is relatively small, it is possible to minimize the disadvantage that the vaporization atomization time is short, and to suppress a reduction in emission performance.

  Here, referring to FIG. 8, the heat generation pattern of the rotary piston engine 1 having the first and second injectors 15 and 16 (refer to the solid line in the embodiment) and the conventional configuration in which the intake port injection is performed. The heat generation pattern of the rotary piston engine (comparative example, see broken line) is compared. The heat generation pattern of the engine of the conventional configuration is a pattern in which two peaks are lined up so that late combustion occurs after the main combustion, which is the first peak, and the heat generation rate (peak height) by the main combustion is also Relatively low. As described above, this is due to the heterogeneity of the air-fuel mixture in the compression / expansion operation chamber. On the other hand, in the engine 1 having the configuration including the first and second injectors 15 and 16, the air-fuel mixture in the compression / expansion working chamber 8 is homogenized, so that late combustion is suppressed. The heat generation rate due to main combustion is high. In addition, in the compression / expansion working chamber 8, the advance side region in the rotor rotation direction is enriched, so that the combustion speed is also increased, and the peak of heat generation due to the main combustion is faster than that of the engine of the conventional configuration. It occurs at the timing. Such improvement of the heat generation pattern (combustion pattern) contributes to improvement of fuel consumption and torque.

  FIG. 9 shows a modification relating to the arrangement of the first and second injectors 15 and 16. In this engine 1, the first injector 15 is on the compression stroke side with the long axis Y interposed therebetween (on the advance side in the rotational direction of the rotor 2), and the second injector 16 is on the intake stroke side with the long axis Y interposed therebetween (the rotor 2 Are arranged on the delay side of the rotation direction).

  The first injector 15 is directed in the direction of the intake ports 11, 12, 13 to inject fuel directly into the intake working chamber 8, and the second injector 16 is directed in the direction of the spark plug 91 to perform the compression operation. Fuel is directly injected into the chamber 8. Since this arrangement increases the spray flight distance of each of the first injector 15 and the second injector 16, this arrangement is advantageous in suppressing the fuel wall surface adhesion. In FIG. 9, the first and second injectors 15 and 16 are arranged so that their axial centers are parallel to the long axis Y, but as described above, the first and second injectors are arranged. The angle at which the injectors 15 and 16 are disposed is not particularly limited. However, from the viewpoint of simplifying the mounting of the pressure accumulator 7, it is desirable to arrange the first and second injectors 15 and 16 in parallel with each other.

  FIG. 10 shows a modification of the pressure accumulator 7. In the accumulator 7, the first fuel supply pipe 71 connects the first injectors 15 in the front and rear rotor housings 3 to each other, while the second fuel supply pipe 72 has front and rear rotors. The second injectors 16 in the housing 3 are connected to each other. For this reason, the first and second fuel supply pipes 71 and 72 are disposed so as to extend in parallel to each other in the direction of the rotation axis X. A communication pipe 77 that communicates the first and second fuel supply pipes 71 and 72 with each other is disposed at the center position in the length direction of the first and second fuel supply pipes 71 and 72. The pressure accumulator 7 is configured so as to have an H-shape that is inclined laterally as a whole. Also in this pressure accumulator 7, since the distance between the injectors 15 and 16 using the first and second fuel supply pipes 71 and 72 and the communication pipe 77 as paths becomes equal, the fuel injection amount of each injector 15 and 16 is The error is equal.

  In the pressure accumulator 7, the other end of the first fuel supply pipe 71 is attached to the other end (the left end in FIG. 10) of the connecting pipe connected to the high pressure fuel pump. A fuel pressure sensor 76 is attached to the left end in FIG. The pressure accumulator 7 also has a third opening at the center in the length direction of the first fuel supply pipe 71 in order to perform drilling of the communication pipe 77, and this opening has a blind plug 74. Is attached. Alternatively, the fuel pressure sensor 76 and the blind plug 74 may be interchanged so that the fuel pressure sensor 76 is attached to the position of the blind plug 74 and the blind plug 74 is attached to the position of the fuel pressure sensor 76.

  Here, a two-rotor type engine having two rotors 2 is exemplified, but the number of rotors 2 is not limited to this.

  As described above, this technique is useful for improving the combustibility in the rotary piston engine.

It is a perspective view which shows the outline | summary of a rotary piston engine. It is sectional drawing which simplified the one part which shows the principal part of the same engine. It is a figure which expands and shows the top vicinity in the rotor housing of the same engine. It is explanatory drawing which shows the fuel-injection direction of a 1st and 2nd injector. It is a top view of the engine which shows the composition of a pressure accumulator. It is a block diagram which shows the structure which concerns on control of a rotary piston engine. It is a timing chart regarding operation of a rotary piston engine. It is the figure which compared the heat generation pattern. FIG. 4 is a view corresponding to FIG. 3 showing a modified example related to the arrangement of the first and second injectors. FIG. 6 is a diagram corresponding to FIG. 5 illustrating a modified example of the pressure accumulator.

Explanation of symbols

1 Rotary Piston Engine 11 Intake Port 15 First Injector (First Fuel Injection Valve)
16 Second injector (second fuel injection valve)
2 Rotor 3 Rotor housing 31 Rotor housing chamber 3a Trochoid inner peripheral surface 4 Intermediate housing (side housing)
5 Side housing 71 First fuel supply pipe 72 Second fuel supply pipe 8 Working chamber 92 Leading side spark plug 91 Trailing side spark plug X Output shaft Y Long axis Z Short shaft

Claims (7)

A rotor housing having a generally elliptical trochoidal inner circumferential surface defined by a major axis and a minor axis orthogonal to each other;
A side housing that forms a rotor accommodating chamber together with the rotor housing by being disposed on both sides of the output shaft direction orthogonal to the major axis and the minor axis, respectively, across the rotor housing;
Three working chambers are defined between the rotor housing chamber and the rotor housing, and by rotating the planets around the output shaft, the respective working chambers are moved in the circumferential direction, and the air intake is sequentially performed. A generally triangular rotor for performing compression, expansion and exhaust strokes;
A first fuel injection valve attached to the rotor housing so as to face the working chamber in the intake stroke and directly injecting fuel into the working chamber in the intake stroke;
A fuel injection device for a rotary piston engine, comprising: a second fuel injection valve attached to the rotor housing so as to face the working chamber in the compression stroke and directly injecting fuel into the working chamber in the compression stroke . The fuel injection device for a rotary piston engine according to claim 1,
An intake port that opens in at least one of the side housings so as to be able to inhale air into the working chamber in communication with the working chamber in the intake stroke;
And at least one spark plug attached to the rotor housing so as to face the working chamber in the compression or expansion stroke,
Each of the first and second fuel injection valves is disposed near a long axis of the rotor housing;
The first fuel injection valve injects fuel in the direction of the intake port when viewed in the output shaft direction;
The second fuel injection valve is a fuel injection device for a rotary piston engine that injects fuel in the direction of the spark plug when viewed in the output shaft direction. The fuel injection device for a rotary piston engine according to claim 1 or 2,
The first and second fuel injection valves are configured to divide and inject fuel supplied to the working chamber,
A fuel injection device for a rotary piston engine, wherein a fuel injection amount of the second fuel injection valve is smaller than a fuel injection amount of the first fuel injection valve. In the fuel-injection apparatus of the rotary piston engine of any one of Claims 1-3,
The first and second fuel injection valves are arranged such that the first fuel injection valve is on the delay side in the rotation direction of the rotor and the second fuel injection valve is on the advance side in the rotation direction of the rotor. A fuel injection device for a rotary piston engine arranged side by side in the rotational direction. In the fuel-injection apparatus of the rotary piston engine of any one of Claims 1-3,
The first and second fuel injection valves are arranged such that the first fuel injection valve is on the advance side in the rotation direction of the rotor and the second fuel injection valve is on the delay side in the rotation direction of the rotor. A fuel injection device for a rotary piston engine arranged side by side in the rotational direction. The fuel injection device for a rotary piston engine according to claim 4 or 5,
The fuel injection device for a rotary piston engine, wherein the first and second fuel injection valves are respectively disposed on both sides of the rotor rotating direction across a long axis of the rotor housing. The rotor housing and the rotor are arranged in a plurality in the output shaft direction with the side housing interposed therebetween, and the first and second fuel injection valves are attached to each of the plurality of rotor housings,
The first and second fuel injection valves are provided so as to extend over the plurality of rotor housings so as to connect the first and second fuel injection valves and supply fuel to the first and second fuel injection valves of the respective rotor housings. A pressure accumulator including a fuel supply pipe and a second fuel supply pipe;
The fuel injection device for a rotary piston engine, wherein the first fuel supply pipe and the second fuel supply pipe communicate with each other at a substantially central position in the length direction.

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