JP5304387B2 - Start control method and start control device for rotary piston engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a startup response as much as possible by shortening a time from fuel injection to first explosion at restart after the automatic stop of a rotary piston engine. <P>SOLUTION: A rotary piston engine is provided in advance with a first fuel injection valve for injecting fuel supplied into an operation chamber during an intake stroke and a second fuel injection valve for directly injecting the fuel into an operation chamber during a compression stroke. At the restart after the automatic stop of an engine, the device executes a process for injecting the fuel into the operation chamber during the compression stroke by the second fuel injection valve (Step S24), a process for rotating a rotor by a drive means for engine start (Step S25) and a process for burning a mixture in the operation chamber into which the fuel is injected by the second fuel injection valve at prescribed timing after the latter stage of the compression stroke through ignition by an ignition plug(Step S26). <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention belongs to a technical field related to a start control method and a start control device of a rotary piston engine, and particularly relates to control at the time of restart after automatic stop of the engine.

  Generally, a 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 inner peripheral surface. This rotary piston engine sequentially performs intake, compression, expansion, and exhaust strokes in each working chamber while moving each of the three working chambers partitioned between the rotor and the housing in the circumferential direction as the rotor rotates. (See, for example, Patent Document 1).

  In such a rotary piston engine, it is common to inject fuel from a fuel injection valve attached to an intake port and / or an intake manifold so that the fuel is supplied into a working chamber in an intake stroke.

  Further, as shown in Patent Document 1, the second half of the intake stroke is directed from the fuel injection valve arranged near the long axis so as to face the working chamber in the intake stroke, and directed in the direction of the spark plug. At a later timing, the fuel may be supplied into the working chamber in the intake stroke by directly injecting the fuel into the working chamber.

On the other hand, it has been conventionally known that a reciprocating engine automatically stops the engine when a predetermined engine automatic stop condition is satisfied, such as during idling, for the purpose of improving fuel efficiency. (For example, refer to Patent Document 2).
JP-A-6-288249 JP 2000-356147 A

  By the way, also in a rotary piston engine, it is desirable to automatically stop the engine when a predetermined engine automatic stop condition is satisfied, and to restart the engine when a predetermined engine restart condition is satisfied thereafter. Such restart after the engine is automatically stopped is required to be performed as quickly as possible.

  However, as described above, in the configuration in which fuel is injected into the intake port or fuel is directly injected into the working chamber in the intake stroke and the fuel is supplied into the working chamber in the intake stroke, the initial explosion from the fuel injection is performed. There is a limit to shortening the time to completion, and there is room for improvement. That is, in the above configuration, when the engine is restarted, fuel is supplied to the working chamber in the intake stroke, the rotor is rotated by the starter motor, and the working chamber supplied with the fuel is used as a compression stroke. At the later ignition timing, ignition by the spark plug is performed, and the air-fuel mixture in the working chamber is combusted. For this reason, it takes time from fuel injection to ignition timing (first explosion).

  The present invention has been made in view of such a point, and an object of the present invention is to reduce the time from fuel injection to the first explosion at the time of restart after the automatic stop of the rotary piston engine, and to start response. Is to improve as much as possible.

In order to achieve the above object, according to the first aspect of the present invention, a rotor housing having a substantially elliptical trochoidal inner circumferential surface defined by a major axis and a minor axis orthogonal to each other, and a side disposed so as to sandwich the rotor housing A rotor is accommodated in a rotor accommodating chamber defined by a housing to define three working chambers, and the rotor moves in a circumferential direction by rotating the planets around the output shaft while moving the working chambers in the circumferential direction. A starting control method of a rotary piston engine configured to sequentially perform intake, compression, expansion, and exhaust strokes in each working chamber. The rotary piston engine has a fuel in the working chamber in the intake stroke. A first fuel injection valve that injects fuel so that is supplied, a second fuel injection valve that directly injects fuel into the working chamber in the compression stroke, An ignition plug for combusting the fuel mixture compressed in the working chamber in the compression stroke, provided in advance and a driving means for starting the engine for rotating the rotor, during the automatic stop of the engine, in the rotor, compression The engine is stopped so that the apex seal that divides the working chamber in the stroke and the working chamber in the intake stroke is positioned on the rotor rotation delay side with respect to the injection port of the second fuel injection valve, At the restart after the automatic stop, the step of injecting fuel into the working chamber in the compression stroke by the second fuel injection valve, the step of rotating the rotor by the driving means, and the second fuel injection valve A step of combusting the air-fuel mixture in the working chamber into which fuel has been injected by ignition with the spark plug at a predetermined timing after the latter half of the compression stroke. Was to so that.

  According to the above start control method, when the engine is restarted, the fuel is injected into the working chamber in the compression stroke by the second fuel injection valve, and the air-fuel mixture is compressed in the working chamber by the rotation of the rotor by the driving means. Ignition by the spark plug is performed at a predetermined timing after the latter half of the compression stroke. Thus, if fuel is injected into the working chamber in the compression stroke (compression stroke injection is performed), the fuel is injected by the first fuel injection valve so that the fuel is supplied into the working chamber in the intake stroke. Compared to the case of performing (intake stroke injection), the time from fuel injection to ignition timing (first explosion) can be shortened, and the restart response can be improved.

  And after an engine start, according to the driving | running state of an engine, the injection mode by a 1st and 2nd fuel injection valve can be changed. That is, when the engine operating state is in a predetermined high load operation region, intake stroke injection is performed by the first fuel injection valve. The intake stroke injection cools the intake air by the effect of latent heat of vaporization of the fuel and increases the intake charge efficiency. As a result, the torque is improved in the high load operation region. On the other hand, when the operating state of the engine is in the partial load operation region, the intake stroke injection by the first fuel injection valve and the compression stroke injection by the second fuel injection valve are performed. That is, the injection by the first and second fuel injection valves is controlled so that the air-fuel ratio of the air-fuel mixture to be combusted becomes a set value set in advance according to the operating state of the engine. In the intake stroke injection, in addition to the effect of improving the charging efficiency by the intake air cooling, the fuel is injected at a timing much earlier than the ignition timing, so that the vaporization atomization time can be secured for a long time. Therefore, the intake stroke injection by the first fuel injection valve is advantageous in forming an air-fuel mixture with good vaporization atomization. However, the flow of the air-fuel mixture (fuel) is relatively delayed with respect to the rotation of the rotor. As a result, particularly in the partial load operation region, the advance region in the rotor rotation direction becomes lean in the compression working chamber, and the rotor rotation direction This causes inhomogeneities such that the region on the delay side of the region becomes rich. Therefore, the fuel is supplied to the relatively lean region by the compression stroke injection. As a result, the heterogeneity of the air-fuel mixture in the working chamber can be eliminated, and the fuel consumption can be improved by improving the combustion characteristics.

Further, when the engine is automatically stopped, an apex seal in the rotor that divides the working chamber in the compression stroke and the working chamber in the intake stroke is positioned on the rotor rotation delay side with respect to the injection port of the second fuel injection valve. Thus, by stopping the engine, the compression stroke injection by the second fuel injection valve can be reliably performed when the engine is restarted.

According to a second aspect of the present invention, there is provided a rotor housing chamber defined by a rotor housing having a substantially elliptical trochoidal inner peripheral surface defined by a major axis and a minor axis orthogonal to each other, and a side housing disposed so as to sandwich the rotor housing. In addition, the rotor is accommodated to divide the three working chambers, and by rotating the planets around the output shaft, the rotors move in the circumferential direction, and the intake and compression are performed in the respective working chambers. In this invention, the rotary piston engine is configured to cause the expansion and exhaust strokes to be sequentially performed. In this invention, the rotary piston engine is supplied with fuel into the working chamber in the intake stroke. The first fuel injection valve for injecting the fuel, the second fuel injection valve for directly injecting the fuel into the working chamber in the compression stroke, and the compression stroke An ignition plug for combusting the air-fuel mixture compressed in the moving chamber; and a drive means for starting the engine for rotating the rotor. The start control device includes the first and second fuel injection valves, the ignition Control means for controlling the operation of the plug and the drive means, and a control means for automatically stopping the engine when a predetermined engine automatic stop condition is satisfied , wherein the control means satisfies the predetermined engine automatic stop condition. Sometimes, the engine has an apex seal that divides the working chamber in the compression stroke and the working chamber in the intake stroke in the rotor so as to be located on the rotor rotation delay side with respect to the injection port of the second fuel injection valve. It stops the, when a predetermined engine restart condition after the automatic stop of the engine is satisfied, to the second fuel injection valve, the compression stroke work In order to inject fuel into the chamber and operate the driving means to rotate the rotor and to burn the air-fuel mixture in the working chamber into which fuel has been injected by the second fuel injection valve, It is assumed that the engine is restarted by causing the spark plug to ignite at a predetermined timing.

  According to the present invention, when the engine is restarted, the control means causes the second fuel injection valve to inject fuel into the working chamber in the compression stroke, operates the drive means to rotate the rotor, Since the ignition plug is ignited at a predetermined timing thereafter, the time from the fuel injection to the ignition timing (first explosion) can be shortened and the restart response is improved as in the first aspect of the invention. be able to.

As described above, according to the start control method and start control device for a rotary piston engine of the present invention, the first fuel injection for injecting fuel to the rotary piston engine so that the fuel is supplied into the working chamber in the intake stroke. A valve and a second fuel injection valve for directly injecting fuel into the working chamber in the compression stroke, and the operation of the rotor in the compression stroke and the intake stroke in the rotor when the engine is automatically stopped The engine is stopped so that the apex seal that divides the chamber is located on the rotor rotation delay side with respect to the injection port of the second fuel injection valve , and the second fuel is restarted after the engine is automatically stopped. The fuel is injected into the working chamber in the compression stroke by the injection valve, the rotor is rotated by the driving means, and the fuel is injected by the second fuel injection valve. By injecting the air-fuel mixture in the working chamber at a predetermined timing after the latter stage of the compression stroke by ignition with an ignition plug, the time from fuel injection to ignition timing (first explosion) is shortened, The restart response can be improved as much as possible.

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

  1 and 2 show an example of a rotary piston engine 1 (hereinafter simply referred to as an engine 1) that is a control target of a start control device 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 (side housing) 4 is sandwiched between them, the two side housings 5 are further sandwiched from both sides so as to be integrated. 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 trochoid inner peripheral surface 3 a drawn by the parallel trochoid curve of each of the rotor housings 3, the inner side surface 5 a of the side housing 5 sandwiching the rotor housing 3 from both sides, and the inner side surfaces 4 a on both sides of the intermediate housing 4, As shown in FIG. 2, a rotor accommodating chamber 31 (cylinder) having a substantially elliptical shape like a bowl when viewed from the direction of the rotation axis X is divided into two sides, a front side and a rear side. One rotor 2 is accommodated in each accommodating chamber 31. Since 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, hereinafter, one rotor accommodating chamber 31 is provided. Will be described.

  The rotor 2 is composed of a substantially triangular block body in which the central portion of each side bulges outward as viewed from the direction of the rotation axis X, and three substantially rectangular flank surfaces between the top portions on the outer periphery thereof. 2a. A recess 2b is 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. Three working chambers 8 are defined in the interior of the rotor accommodating chamber 31 by 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, respectively. Therefore, in the engine 1, the first to third working chambers 8 are formed on the front side, and the fourth to sixth working chambers 8 are formed on the rear side (see FIG. 6). .

  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). The three working chambers 8 move in the circumferential direction during one rotation of the rotor 2, and intake, compression, expansion (combustion), and exhaust strokes are performed in each of them, and the rotational force generated thereby is generated by the rotor. 2 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 31 is divided by the long axis Y of the rotor accommodating chamber 31 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, this shows an intake stroke in which an air-fuel mixture is formed by intake air and injected fuel (hereinafter, the working chamber in this state is referred to as an intake working chamber). When the intake working chamber 8 shifts to the compression stroke as the rotor 2 rotates, the air-fuel mixture is compressed therein (hereinafter, the working chamber in this state is also referred to as the compression working chamber 8). After that, as shown in the working chamber 8 shown on the right side of FIG. 2, it is ignited by trailing and leading side ignition plugs 91 and 92, which will be described later, at a predetermined timing from the latter stage of the compression stroke to the expansion stroke. (Hereinafter, the working chamber in this state 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, the above-described strokes are repeated.

  A plurality (three in this embodiment) 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 31 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 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 over the area.

  A plurality (two in this embodiment) of exhaust ports 10 communicate with the exhaust working chamber 8. That is, one 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, another exhaust port 10 is 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. 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.

  A first injector (first fuel injection valve) 15 and a second injector (second fuel injection valve) 16 are attached to the vicinity of the top of the rotor housing 3 corresponding to the long axis Y of the rotor housing 3. Yes. 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 from 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. In the present embodiment, the first injector 15 has a total of eight directions (lines D1-1, D1-2, D2-1, and D2 shown in FIG. 3) including four directions in the rotor rotational 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. In addition, the injection direction of the 1st injector 15 shown in FIG. 3 is an illustration, and is not limited to this.

  As shown in FIGS. 2 and 3, the second injector 16 is disposed with respect to the long axis Y on the advance side in the rotor rotation direction, that is, on the right side in FIG. 3. The second injector 16 is configured to inject fuel directly into the compression working chamber 8, and the second injector 16 particularly when viewed from the direction of the rotation axis X shown in FIG. The fuel is injected in the direction from the vicinity of the top to the trailing spark plug 91. 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. In the present embodiment, the second injector 16 is The two injection holes are formed so as to inject fuel in one direction and in two directions with respect to the width direction of the rotor. By spraying fuel in two directions (see lines D5-1 and D5-2 shown in FIG. 3) with respect to the width direction of the rotor, it is avoided that the spray directly hits the plug hole of the trailing spark plug 91. Is possible. In addition, the injection direction of the 2nd injector 16 shown in FIG. 3 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 portion, 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 their axial directions 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 the two rotor housing chambers 31 on the front side and the rear side, respectively. The first and second injectors 15 and 16 are disposed so as to be parallel to each other. Therefore, in this engine 1, a total of four injectors 15 and 16 are arranged so as to be parallel to each other.

  The first and second injectors 15 and 16 are connected to one pressure accumulator 7, and the pressure accumulator 7 is connected to a high-pressure fuel pump (not shown). The pressure 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 first and second 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 has a front side and a rear side so that the first injector 15 attached to the front rotor housing 3 and the second injector 16 attached to the rear rotor housing 3 communicate with each other. The rotor housing 3 is disposed so as to extend in the direction of the rotation axis X (more precisely, a direction inclined by a predetermined angle with respect to the rotation axis X). On the other hand, the second fuel supply pipe 72 is connected to the front 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. And the rotor housing 3 on the rear side so as to extend in the direction of the rotation axis X (more precisely, the direction inclined with respect to the rotation axis X opposite to the first fuel supply pipe 71 by a predetermined angle). It is arranged. 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.

  Each of the first and second fuel supply pipes 71 and 72 has a connecting portion 73 that protrudes downward at each of both end portions thereof and is fitted onto the upper end portion of the first or second injector 15 or 16. Yes. As described above, since the four injectors 15 and 16 are arranged in parallel to each other, the connecting portions 73 are aligned with the injectors 15 and 16, and the connecting portions 73 are connected to the injectors 15 and 16, respectively. 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.

  In the pressure accumulator 7, a fuel pressure sensor 76 (shown only in FIG. 4) is located at a position where the first and second fuel supply pipes 71, 72 intersect (position where the distances from the four injectors 15, 16 are substantially equal). ) Is attached. The fuel pressure sensor 76 measures the fuel pressure in the accumulator 7, and outputs a measurement signal to a control unit 100 (hereinafter referred to as ECU 100) described later (see FIG. 4). The ECU 100 uses the fuel pressure signal when setting the pulse width (fuel injection signal) supplied to the first and second injectors 15 and 16.

  A trailing side ignition plug 91 and a leading side ignition are respectively provided at a trailing side (delay side) position and a leading side (advance side) position in the rotor rotational direction across the short axis Z at the side portion of the rotor housing 3. A plug 92 is attached. These two spark plugs 91 and 92 face the compression / expansion working chamber 8 and burn the air-fuel mixture in the compression / expansion working chamber 8 (that is, the air-fuel mixture compressed in the compression working chamber 8). Ignite simultaneously or in order of leading and trailing sides. 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. 4 shows the configuration of the control system of the engine 1. With respect to the ECU 100, an accelerator opening sensor 101 that detects an accelerator opening corresponding to the amount of depression of an accelerator pedal of a vehicle occupant equipped with the engine 1, a vehicle speed sensor 102 that detects a traveling speed of the vehicle, and an eccentric shaft 6 An eccentric angle sensor 103 for detecting the rotation angle (hereinafter referred to as an eccentric angle), a brake sensor 104 for detecting the depression amount of the occupant's brake pedal, a water temperature sensor 105 for detecting the temperature of cooling water of the engine 1, and an intake passage The air flow sensor 106 for detecting the intake flow rate sucked in, the linear O ₂ sensor 107 for detecting the oxygen concentration in the exhaust gas, and the fuel pressure sensor 76 each output a detection signal. The ECU 100 receives signals from the respective sensors, determines the operating state of the engine 1 based on the input signals, and determines the opening of the electric throttle valve 108 and each operation according to the operating state. The ignition timing by the ignition plugs 91 and 92 in the chamber 8 and the fuel injection amount and fuel injection timing by the first and second injectors 15 and 16 are controlled. In addition, when the engine 1 is started, the ECU 100 drives the starter motor 109 as engine starting drive means to rotate the rotor 2. Thus, the ECU 100 constitutes the control means of the start control device of the present invention that controls the operations of the first and second injectors 15 and 16, the spark plugs 91 and 92, and the starter motor 109.

  The ECU 100 includes an automatic stop control unit 100a that automatically stops the engine 1 as will be described later, a restart control unit 100b that restarts after the engine 1 is automatically stopped, and a normal operation after the engine 1 is started. And the fuel injection control unit 100c for controlling the fuel injection by controlling the operation of the second injectors 15 and 16, and the operation of the trailing and leading spark plugs 91 and 92 during the normal operation of the engine 1. An ignition control unit 100d that controls ignition and an auxiliary machine load control unit 100e that controls the load of the auxiliary machine 110 of the engine 1 at the time of automatic stop by the automatic stop control unit 100a.

  Here, in the engine 1, as shown in the map of FIG. 5, the operation region is divided into a high load operation region and a partial load operation region, and the fuel injection control unit 100c The operation of the first and second injectors 15 and 16 is controlled so that the fuel injection modes by the first and second injectors 15 and 16 are different from each other. The air-fuel ratio is set to be different between the high load operation region and the partial load operation region. That is, the boundary line between the load operation region and the partial load operation region is determined by the air-fuel ratio. Note that the engine speed, which is the horizontal axis of the map of FIG. 5, is obtained by calculating the rate of change of the eccentric angle detected by the eccentric angle sensor 103 with respect to time.

  Thus, in the partial load operation region, the fuel injection control unit 100c performs an intake stroke injection in which fuel is injected into the working chamber 8 in the intake stroke by the first injector 15 and an operation in the compression stroke by the second injector 16. Both the compression stroke injection for injecting fuel into the chamber 8 are executed, and only the intake stroke injection by the first injector 15 is executed in the high load operation region.

  In addition, the fuel injection control unit 100c controls the fuel injection amount by the first injector 15 in the high load operation region so that the air-fuel ratio of the air-fuel mixture to be combusted becomes a set value set in advance according to the operating state of the engine. In the partial load operation region, the fuel injection amounts by the first and second injectors 15 and 16 are respectively set. The fuel injection control unit 100c causes the first injector 15 to inject fuel with the set fuel injection amount in the high load operation region, and the first and second injectors 15 and 16 in the partial load operation region. The fuel is injected with the set fuel injection amount. In the partial load operation region, the fuel supplied into the working chamber 8 in order to obtain the air-fuel ratio of the above set value is divided and injected by the first and second injectors 15 and 16, and the fuel injection by the first injector 15 is performed. The total amount of the amount and the amount of fuel injected by the second injector 16 is made equal to the amount of fuel to be supplied into the working chamber 8. The ratio between the fuel injection amount by the first injector 15 and the fuel injection amount by the second injector 16 is set in advance. In this embodiment, the fuel injection amount by the first injector 15 is the fuel injection amount by the second injector 16. It is set to be larger than the amount. This is because the intake stroke injection by the first injector 15 is advantageous in forming an air-fuel mixture with good vaporization atomization because fuel is injected at a timing much earlier than the ignition timing. .

  Next, fuel injection control in the fuel injection control unit 100c will be described with reference to the timing chart of FIG. In FIG. 6, the intake stroke injection and the compression stroke injection are described as “intake injection” and “compression injection”, respectively.

  The fuel injection timing (intake stroke injection timing) of the first injector 15 by the fuel injection control unit 100c is the state in which the rotor 2 is in the state shown in FIG. 2, that is, the volume of the compression / expansion working chamber 8 is minimized (on compression) The rotation angle (eccentric angle) on the rotational direction side of the eccentric shaft 6 is set within the range of −450 ° to −330 ° ATDC when the dead point (TDC) is set as a reference (0 °). The rotational position 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 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. In addition, 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 stroke injection by the first injector 15, and an air-fuel mixture with good vaporization atomization is formed by securing a long vaporization atomization time. Further, in the intake stroke injection, the intake air is cooled by the latent heat of vaporization of the fuel, and the charging efficiency can be improved. Thereafter, the working chamber 8 shifts to the compression stroke.

  The fuel injection timing (compression stroke injection timing) of the second injector 16 by the fuel injection control unit 100c is set in the range of −180 ° to −150 ° ATDC in terms of the eccentric angle. The rotational position 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 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, and in particular, the fuel injection amount by the first injector 15 is reduced. In the partial load operation region, in the compression / expansion working chamber 8, inhomogeneity occurs 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, fuel is injected in the direction of the spark plug 91 by the second injector 16, so that in the compression working chamber 8 in relation 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 in the rotor rotation direction can be eliminated.

  Then, after fuel injection is performed by both the first and second injectors 15 and 16, or only by the first injector 15, the ignition control unit 100d includes two ignition plugs 91 on the trailing side and the leading side. 92 are ignited at the predetermined timing, simultaneously or in the order of the leading side and the trailing side.

  In addition, since the compression stroke injection is late with respect to the intake stroke injection, it is difficult to secure a sufficient vaporization atomization time. However, since the amount of fuel injected by the second injector 16 is smaller than the amount of fuel injected by the first injector 15, the disadvantage that the vaporization atomization time is short is minimized and the deterioration of the emission property is suppressed. It is possible.

  The automatic stop control unit 100a automatically stops the engine 1 when a predetermined engine automatic stop condition is satisfied. The engine automatic stop condition is satisfied, for example, when the brake pedal depression amount detected by the brake sensor 104 continues for a predetermined time or longer and the vehicle speed detected by the vehicle speed sensor 102 is equal to or lower than the predetermined speed. (That is, when it is assumed that the idle operation state of the engine 1 is continued for a predetermined time).

  At the time of this automatic stop, the automatic stop control unit 100a cooperates with the auxiliary machine load control unit 100e so that the apex seal that partitions the compression working chamber 8 and the intake working chamber 8 in the rotor 2 is the second injector 16. The engine 1 is stopped so as to be positioned on the rotor rotation delay side with respect to the nozzle hole. This is because, as will be described later, when the engine 1 is restarted, fuel is injected into the compression working chamber 8 to shorten the time from fuel injection to the first explosion.

  Specifically, the automatic stop control unit 100a causes the fuel injection control unit 100c to stop fuel injection by the first and second injectors 15 and 16 when the engine automatic stop condition is satisfied. Thereby, fuel injection stops and the rotational speed of the rotor 2 falls. The position at which the rotor 2 stops is substantially determined by the balance of the air amount in the three working chambers 8 immediately before the rotor 2 stops, and the engine speed (tsu, idle speed) immediately before the fuel injection stops. Therefore, the working chamber 8 that becomes a compression stroke when the rotor 2 is stopped is also determined. However, when the rotor 2 stops, the apex seal that separates the compression working chamber 8 and the intake working chamber 8 in the rotor 2 is positioned closer to the rotor rotation advance side than the injection port of the second injector 16, as will be described later. When the engine 1 is restarted, fuel cannot be injected into the compression working chamber 8 by the second injector 16. Therefore, after the fuel injection is stopped, the load on the auxiliary machine 110 of the engine 1 is adjusted, and the rotor 2, the apex seal that divides the compression working chamber 8 and the intake working chamber 8, is behind the rotor rotation of the second injector 16. Stop to be on the side. In the present embodiment, the auxiliary machine 110 is an alternator, adjusts the load on the engine 1 according to the amount of power generation, and stops the rotor 2 with an eccentric angle in the range of −180 ° to −150 ° ATDC. . In addition to the alternator, the auxiliary machine 110 may be, for example, a compressor of an air conditioner or the like, and may be anything as long as the load on the engine 1 can be adjusted.

  The automatic stop control unit 100a obtains the load of the auxiliary machine 110 based on the eccentric angle detected by the eccentric angle sensor 103 and the engine speed obtained from the rate of change of the eccentric angle with respect to time. Is transmitted to the auxiliary load control unit 100e to cause the auxiliary load control unit 100e to control the auxiliary device 110 so that the load is obtained.

  The engine automatic stop control by the automatic stop control unit 100a will be described with reference to the flowchart of FIG.

  In the first step S1, detection data is input from each sensor, and in the next step S2, it is determined whether or not an engine automatic stop condition is satisfied.

  When the determination in step S2 is NO, the engine automatic stop control is terminated. On the other hand, when the determination in step S2 is YES, the process proceeds to step S3, and the first and first operations are performed with respect to the fuel injection control unit 100c. 2 Instructs the fuel injection by the injectors 15 and 16 to stop.

  In step S4 following step S3, the load on the auxiliary machine 110 is determined based on the eccentric angle input from the eccentric angle sensor 103 and the engine speed obtained from the rate of change of the eccentric angle with respect to time. In S5, the determined load information is transmitted to the auxiliary machine load control unit 100e, and the auxiliary machine load control unit 100e controls the auxiliary machine 110 so that the load is obtained.

  In the next step S6, the eccentric angle is input from the eccentric angle sensor 103. In the next step S7, whether or not the engine 1 has stopped (that is, whether or not the eccentric angle detected by the eccentric angle sensor 103 has changed). If the determination in step S7 is NO, the process returns to step S4. On the other hand, if the determination in step S6 is YES, the engine automatic stop control is terminated as it is.

  The load of the auxiliary machine 110 may be determined only immediately after the fuel injection is stopped, and the load may be continued until the engine 1 is stopped. In this way, when the rotor 2 stops, the apex seal that partitions the compression working chamber 8 and the intake working chamber 8 in the rotor 2 can be positioned on the rotor rotation advance side with respect to the injection port of the second injector 16. However, in this embodiment, as a precaution, when the above-mentioned apex seal is on the rotor rotation advance side with respect to the injection port of the second injector 16 at the time of restart of the engine 1 as described below, Since fuel is supplied into the intake working chamber 8, no problem occurs. However, in order to stop the rotor 2 more precisely at the target stop position and to inject fuel into the compression working chamber 8 as much as possible, it is preferable to perform feedback control as shown in the flowchart of FIG.

  The restart control unit 100b restarts the engine 1 when a predetermined engine restart condition is satisfied after the engine 1 is automatically stopped. The engine restart condition is satisfied when, for example, the accelerator opening (the amount of depression of the accelerator pedal) detected by the accelerator opening sensor 101 is a predetermined value or more, or when the engine automatic stop condition is that of the engine 1 This is the case when it is released after stopping.

  At the time of this restart, the restart control unit 100b causes the second injector 16 to inject fuel into the working chamber 8 in the compression stroke. At this time, the restart control unit 100b causes the first injector 15 to inject fuel into the working chamber 8 in the intake stroke (the working chamber 8 in the next compression stroke). After fuel injection by the first and second injectors 15 and 16, the starter motor 109 is driven to rotate the rotor 2 (cranking). When the rotor 2 is stopped on the rotor rotation delay side with respect to the target stop position, the starter motor 109 may be driven before the fuel injection or simultaneously with the fuel injection. Further, the fuel injection by the first injector 15 may not be performed simultaneously with the fuel injection by the second injector 16, and may be performed until the working chamber 8 in the intake stroke shifts to the compression stroke.

  Then, the air-fuel mixture in the working chamber 8 in which the fuel is injected by the second injector 16 is subjected to the trailing side and leading side ignition at the predetermined timing after the latter half of the compression stroke (same as the ignition timing during normal operation). Combustion is performed by ignition (initial ignition) by the plugs 91 and 92. Thereafter, normal operation is performed, and when it is time to burn the air-fuel mixture in the working chamber 8 into which fuel has been injected by the first injector 15, the second ignition is performed.

Here, when the apex seal that separates the compression working chamber 8 and the intake working chamber 8 in the rotor 2 is closer to the rotor rotation advance side than the injection port of the second injector 16 at the time of restarting, restarting is performed. The controller 100b does not perform fuel injection by the second injector 16, but causes the first injector 15 to inject fuel into the working chamber 8 in the intake stroke. After this fuel injection (may be before fuel injection or simultaneously with fuel injection), the starter motor 109 is driven to rotate the rotor 2 (cranking). Then, the air-fuel mixture in the working chamber 8 to which the fuel injected by the first injector 15 is supplied is supplied to the trailing side and the leading side at the predetermined timing after the latter half of the compression stroke (same as the ignition timing during normal operation). Combustion is performed by ignition (first ignition) by the side ignition plugs 91 and 92. After this, normal operation is performed.

  The engine restart control by the restart control unit 100b will be described with reference to the flowchart of FIG.

  In the first step S21, detection data is input from each sensor, and in the next step S22, it is determined whether or not an engine restart condition is satisfied.

  When the determination in step S22 is NO, the engine restart control is ended. On the other hand, when the determination in step S22 is YES, the process proceeds to step S23, and whether or not the stop position of the rotor 2 is normal. That is, it is determined whether or not the apex seal that partitions the compression working chamber 8 and the intake working chamber 8 in the stopped rotor 2 is positioned on the rotor rotation delay side with respect to the injection port of the second injector 16.

  When the determination in step S23 is YES, the process proceeds to step S24 where the second injector 16 injects fuel into the working chamber 8 in the compression stroke (compression stroke injection), and the first injector 15 Fuel is injected into the working chamber 8 in the intake stroke.

  In step S25 following step S24, the starter motor 109 is driven to rotate the rotor 2, and in the next step S26, the air-fuel mixture in the working chamber 8 into which fuel is injected by the second injector 16 is burned. Then, ignition (initial ignition) is performed by the spark plugs 91 and 92 at a predetermined timing, and then the process proceeds to step S30.

  On the other hand, when the determination in step S23 is NO, the process proceeds to step S27, and the first injector 15 injects fuel into the working chamber 8 in the intake stroke (intake stroke injection).

  In step S28 following step S27, the starter motor 109 is driven to rotate the rotor 2, and in the next step S29, the air-fuel mixture in the working chamber 8 into which fuel is injected by the first injector 16 is burned. Then, ignition (initial ignition) is performed by the spark plugs 91 and 92 at a predetermined timing, and then the process proceeds to step S30.

  In step S30, the operation is shifted to the normal operation, and the fuel injection control unit 100c and the ignition control unit 100d are controlled in the normal operation of the first and second injectors 15 and 16 and the spark plugs 91 and 92.

  Therefore, in the present embodiment, when the engine 1 is restarted after being automatically stopped, the second injector 16 injects fuel into the working chamber 8 in the compression stroke, and the air-fuel mixture in the working chamber 8 is compressed into the compression stroke. Since the fuel is burned by ignition by the spark plugs 91 and 92 at a predetermined timing after the latter period, the first injector 15 starts the fuel injection compared to the case where the fuel is injected into the working chamber 8 in the intake stroke. The time until the ignition timing (first explosion) can be shortened, and the restart response can be improved.

In the above embodiment, the first fuel injection valve of the present invention is configured by the first injector 15 that directly injects fuel into the working chamber 8 in the intake stroke. Or the first fuel injection valve at both the injector and the first injector 15 for supplying the fuel into the working chamber 8 in the intake stroke via the intake port 11. May be configured. The fuel injection by the injector that injects fuel into the intake port 11 is preferably performed at the opening timing of the intake port 11.

  Furthermore, in the above embodiment, the engine 1 is configured with two cylinders (two rotors 2), but may be configured with one cylinder or three or more cylinders.

  The present invention is useful for a start control method and a start control device at the time of restart after a rotary piston engine is automatically stopped.

It is a perspective view which shows the outline | summary of the rotary piston engine which is a control object of the starting control apparatus which concerns on embodiment of this invention. It is sectional drawing which simplified the one part which shows the principal part of a rotary piston engine. It is a figure which expands and shows the top vicinity in the rotor housing of a rotary piston engine. It is a block diagram which shows the structure of the control system of a rotary piston engine. It is a figure which shows the example of the map of the driving | operation area | region regarding fuel-injection control. It is a timing chart regarding operation of a rotary piston engine. It is a flowchart which shows the engine automatic stop control by the automatic stop control part of ECU. It is a flowchart which shows the engine restart control by the restart control part of ECU.

DESCRIPTION OF SYMBOLS 1 Rotary piston engine 2 Rotor 3 Rotor housing 3a Trochoid inner peripheral surface 4 Intermediate housing (side housing)
5 Side housing 6 Eccentric shaft (output shaft)
8 Working chamber 15 1st injector (1st fuel injection valve)
16 Second injector (second fuel injection valve)
31 Rotor storage chamber 91 Trailing side spark plug 92 Leading side spark plug 100 ECU (control means)
109 Starter motor (drive means for starting the engine)
110 Auxiliary machine Y Long axis Z Short axis

Claims (2)

The rotor is housed in a rotor housing chamber defined by 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 a side housing arranged so as to sandwich the rotor housing. The three working chambers are partitioned, and the rotor rotates in a planetary motion around the output shaft, thereby moving the working chambers in the circumferential direction. In each working chamber, intake, compression, expansion, and exhaust are performed. A starting control method of a rotary piston engine configured to perform a stroke in order,
In the above rotary piston engine,
A first fuel injection valve for injecting fuel so that fuel is supplied into the working chamber in the intake stroke;
A second fuel injection valve that directly injects fuel into the working chamber in the compression stroke;
A spark plug for burning the air-fuel mixture compressed in the working chamber in the compression stroke;
Driving means for starting the engine for rotating the rotor;
In advance,
When the engine is automatically stopped, the apex seal that divides the working chamber in the compression stroke and the working chamber in the intake stroke of the rotor is positioned on the rotor rotation delay side with respect to the injection port of the second fuel injection valve. The engine is stopped,
When restarting the engine after the automatic stop,
Injecting fuel into the working chamber in the compression stroke by the second fuel injection valve;
Rotating the rotor by the driving means;
Burning the air-fuel mixture in the working chamber into which fuel has been injected by the second fuel injection valve at a predetermined timing after the latter stage of the compression stroke by ignition with the spark plug;
The starting control method of the rotary piston engine characterized by performing this. The rotor is housed in a rotor housing chamber defined by 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 a side housing arranged so as to sandwich the rotor housing. The three working chambers are partitioned, and the rotor rotates in a planetary motion around the output shaft, thereby moving the working chambers in the circumferential direction. In each working chamber, intake, compression, expansion, and exhaust are performed. A starting control device for a rotary piston engine configured to perform a stroke in order,
The rotary piston engine
A first fuel injection valve for injecting fuel so that fuel is supplied into the working chamber in the intake stroke;
A second fuel injection valve that directly injects fuel into the working chamber in the compression stroke;
A spark plug for burning the air-fuel mixture compressed in the working chamber in the compression stroke;
Driving means for starting the engine for rotating the rotor;
Have
Control means for controlling the operations of the first and second fuel injection valves, the spark plug, and the drive means, and for automatically stopping the engine when a predetermined engine automatic stop condition is satisfied ;
When the predetermined engine automatic stop condition is satisfied , the control means includes an apex seal that divides the working chamber in the compression stroke and the working chamber in the intake stroke in the rotor. The engine is stopped so as to be located on the rotor rotation delay side with respect to the nozzle hole, and when a predetermined engine restart condition is satisfied after the engine is automatically stopped, the second fuel injection valve is in a compression stroke. In the later stage of the compression stroke, the fuel is injected into the working chamber, the driving means is operated to rotate the rotor, and the air-fuel mixture in the working chamber in which the fuel is injected by the second fuel injection valve is combusted. The rotary engine is configured to restart the engine by causing the spark plug to ignite at a predetermined timing. Start control system for a piston engine.

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