JP5233667B2 - Direct injection engine fuel injection system - Google Patents

Description

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

  The direct injection engine is an engine that includes a fuel injection valve disposed facing a cylinder and directly injects fuel into each cylinder by the fuel injection valve. For example, Patent Document 1 discloses, as an example of a direct injection engine, a rotary piston engine configured by housing a substantially triangular rotor in a rotor housing chamber. The rotary piston engine is an engine that sequentially performs intake, compression, expansion, and exhaust strokes while moving each of the three working chambers partitioned between the rotor and the housing in the circumferential direction as the rotor rotates. In the rotary piston engine disclosed in the patent document, a fuel injection valve disposed near the long axis so as to face the working chamber in the intake stroke directly injects fuel into the working chamber.

In such a direct injection engine, each fuel injection valve is connected to a pressure accumulator that stores fuel in a high pressure state, and the pressure accumulator supplies high pressure fuel to each fuel injection valve. The pressure accumulator is connected to a high-pressure fuel pump that boosts and supplies the fuel supplied from the fuel tank. The high-pressure fuel pump is a reciprocating drive type pump provided with a plunger, and the high-pressure fuel pump intermittently supplies fuel to the accumulator when a pump driving cam that rotates as the engine operates reciprocates the plunger. The fuel pressure in the accumulator is increased by pumping.
JP-A-6-288249

  By the way, since the direct injection engine has the characteristic of directly injecting fuel into each cylinder, the degree of freedom of the timing of fuel injection is high. Therefore, the fuel to be supplied into the cylinder is dividedly injected so that the fuel is injected into the cylinder at each timing when the cylinder is in the intake stroke and when it is in the compression stroke, thereby improving combustion. There are cases where it is not intended.

  However, in the fuel split injection, the number of fuel injections (per crankshaft rotation) with respect to the engine speed increases, so that the decrease in the fuel pressure of the pressure accumulator increases accordingly. Performing the next fuel injection while the fuel pressure in the accumulator remains lowered leads to deterioration of the spray characteristics of the fuel injection valve, and lowers the vaporization and atomization of the fuel.

  As a measure for solving this, it is possible to increase the number of times the high-pressure fuel pump is driven with respect to the engine speed to cope with the increase in the number of fuel injections. The number of times the high-pressure fuel pump is driven can be increased, for example, by increasing the number of cam peaks of the pump drive cam. Increasing the number of times the high-pressure fuel pump is driven can increase the number of times the accumulator is increased, and prevent the fuel pressure in the accumulator from being lowered. This can avoid the fuel injection valve performing fuel injection while the fuel pressure in the pressure accumulator remains lowered. That is, fuel atomization can be improved.

  However, the applicant of the present application has noticed that the measure for increasing the number of times of driving the high-pressure fuel pump increases the driving resistance of the fuel pump, and therefore the efficiency of the entire engine can be reduced.

  The fuel supply device for a direct injection engine disclosed herein aims to achieve both improvement of fuel vaporization and suppression of pump drive resistance.

  The applicant of the present application decided to perform the fuel injection through the fuel injection valve twice while the fuel pump performs the fuel pumping once so that the number of times the fuel pump is driven does not increase. Further, when comparing the fuel injection during the intake stroke and the fuel injection during the compression stroke, the fuel injection during the compression stroke has a relatively high in-cylinder pressure, and the vaporization atomization time until ignition is relatively high. Therefore, better spray characteristics are required as compared with fuel injection during the intake stroke. On the other hand, when the fuel injection is performed twice, the fuel injection performed first has a relatively high fuel pressure of the accumulator, so that the spray characteristics are improved, and the fuel injection performed later is performed by the previous fuel injection. Since the fuel pressure is lowered, the spray characteristics are relatively deteriorated. Therefore, among the fuel injection performed twice for one fuel pumping by the fuel pump, the first fuel injection is performed during the compression stroke so as to ensure good spray characteristics and the in-cylinder pressure is relatively low. At the same time, fuel injection during the intake stroke that can ensure a long vaporization atomization time until ignition is performed for the second time.

A fuel injection device for a direct injection engine includes an engine body having at least one cylinder that sequentially repeats intake, compression, expansion, and exhaust strokes, a fuel injection valve that directly injects fuel into the cylinder, and the fuel injection An accumulator that is connected to a valve and supplies high-pressure fuel to the fuel injection valve, and a reciprocating drive that boosts the fuel pressure in the accumulator by intermittently pumping the fuel to the accumulator along with the reciprocating drive. The engine body has a plurality of cylinders that perform each of the strokes in phases different from each other, and one fuel injection valve is disposed in each of the cylinders. each fuel injection valve is connected to the accumulator, the fuel injection valve, to injection and when said cylinder is in the intake stroke, the fuel in the respective timings of the time in the compression stroke into the cylinder Is configured, the engine body, the fuel pump is to be performed once pumping fuel, after the fuel injection valve of the specific cylinder in a particular cylinder in the compression stroke fuel is injected, the specific cylinder The fuel injection valve of the cylinder in the intake stroke, which is different from the above, injects fuel, thereby injecting the fuel twice. That is, the two fuel injections are performed on different cylinders.

  Injecting fuel twice through the fuel injection valve while the fuel pump performs fuel pumping once reduces the number of times the fuel pump is driven. Therefore, the driving resistance of the fuel pump can be reduced.

  On the other hand, by performing two fuel injections in the order of the fuel injection during the compression stroke and the fuel injection during the intake stroke, the fuel injection during the compression stroke ensures good spray characteristics and a short vaporization atomization time. Thus, an air-fuel mixture with good vaporization atomization can be formed in the cylinder. At the same time, the second fuel injection, in which the spray characteristics are relatively poor, is performed during the intake stroke in which the in-cylinder pressure is relatively low and a long vaporization atomization time is ensured. Profit can be minimized. As a result, the vaporization and atomization of the fuel dividedly supplied into the cylinder can be improved as a whole.

  Coexistence of a decrease in the driving resistance of the fuel pump and an improvement in the vaporization and atomization of the fuel can be effective in greatly improving the fuel efficiency.

In the fuel injection device for a direct injection engine, the engine body includes a rotor housed in a rotor housing chamber to define three working chambers, and each rotor operates in a planetary rotation around an output shaft. A rotary piston engine having a cylinder configured to sequentially perform intake, compression, expansion, and exhaust strokes while moving the chamber in a circumferential direction, and the fuel injection valve is configured to The second two are disposed, and the first and second fuel injection valves are connected to the accumulator, respectively, and the rotary piston engine is configured such that when the working chamber is in the intake stroke, The fuel injection valve is configured to inject fuel, and the second fuel injection valve is configured to inject fuel when the working chamber is in the compression stroke. In contrast to the fuel pump pumping the fuel once, after the second fuel injection valve injects fuel in the specific working chamber in the compression stroke, the next working chamber is in the intake stroke with respect to the specific working chamber. When the first fuel injection valve injects fuel, the fuel is injected twice through the first and second fuel injection valves.

In the rotary piston engine, because of the geometrical relationship associated with the rotation of the rotor, after the second fuel injection valve injects fuel in the specific working chamber in the compression stroke, the next working chamber takes air into the specific working chamber. The rotor rotation angle (exsen angle) until the first fuel injection valve injects fuel during the stroke is small. Therefore, the interval between the two fuel injection timings is shortened, which is advantageous in injecting fuel twice.

The fuel pump is reciprocated by a pump drive cam that rotates as the engine body operates, and the rotary piston engine rotates in a planetary manner with respect to an eccentric shaft while being accommodated in a rotor accommodating chamber and the rotor accommodating chamber. A plurality of cylinders configured to include a rotor supported to move; the pump drive cam is provided on the eccentric shaft; and the number of cam peaks of the pump drive cam is included in the rotary piston engine It may be set to be the same as the number of cylinders.

In a rotary piston engine in which three working chambers are defined for one cylinder, one ignition is performed in each cylinder while the eccentric shaft rotates once. Therefore, by providing a pump drive cam having the same number of cam crests as the number of cylinders on the eccentric shaft, the fuel pump performs the same number of pumping as the number of cylinders during one revolution of the eccentric shaft. It is possible to establish two fuel injections for one pumping.

The fuel injection device of the direct injection engine is further a reciprocating engine in which the engine body has a plurality of cylinders each provided with intake and exhaust valves, and the fuel injection valve includes a compression stroke when the cylinder is in an intake stroke, and a compression stroke The engine body is configured to inject the fuel into the cylinder at respective timings when the fuel pump is in the fuel injection state, and the engine body is configured to inject fuel during the compression stroke, whereas the fuel pump performs the fuel pumping once. And fuel is injected twice through the fuel injection valve in the order of fuel injection during the intake stroke, the fuel pump is provided on a camshaft that drives the intake and exhaust valves to open and close, and the engine It is driven back and forth by a pump drive cam that rotates with the operation of the main body, and the number of cam peaks of the pump drive cam is the same as the number of cylinders of the engine main body. It is set, and the phase angle of the valve opening and closing cam provided on the camshaft, the phase angle of the pump drive cam are offset from one another.

In the reciprocating engine, ignition is performed once in each cylinder while the camshaft rotates once. Therefore, by providing the camshaft with a pump drive cam having the same number of cam crests as the number of cylinders, it is possible to establish two fuel injections for one pumping of the fuel pump.

Further, when the phase angle of the valve opening / closing cam and the phase angle of the pump drive cam are made to coincide with each other, the valve reaction force and the pump drive reaction force simultaneously act on the cam shaft. Therefore, it is preferable to shift the timing at which the reaction force acts on the cam shaft by shifting the phase angle of the valve opening / closing cam and the phase angle of the pump drive cam.

  The fuel injection amount during the compression stroke may be smaller than the fuel injection amount during the intake stroke.

  By setting the fuel injection amount that is injected first during the compression stroke to a relatively small amount, a decrease in the fuel pressure of the accumulator can be suppressed. As a result, good spray characteristics can be ensured even during the second fuel injection.

  In addition, fuel injection during the compression stroke is originally performed for the purpose of locally enriching the combustion chamber while not being able to ensure a long vaporization atomization time. Therefore, the amount of fuel injection may be relatively small, and in this respect as well, it is reasonable to first inject fuel during the compression stroke.

  As described above, the fuel injection device of the direct injection engine reduces the number of times the fuel pump is driven by injecting fuel twice through the fuel injection valve, whereas the fuel pump performs fuel pumping once. The driving resistance of the fuel pump can be reduced. At the same time, two fuel injections are performed in the order of the fuel injection during the compression stroke and the fuel injection during the intake stroke, so that the fuel injection during the compression stroke ensures a good spray characteristic and a short vaporization mist. The fuel vaporization atomization is improved as a result of minimizing the disadvantage caused by the low spray characteristics by performing the second fuel injection during the intake stroke while forming a good air-fuel mixture during the vaporization time Can do. As a result, the fuel efficiency of the direct injection engine can be improved.

  Hereinafter, a fuel injection device for a direct injection 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 an engine 1) as one of direct injection engines. 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. 9).

  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). After that, 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, 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 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 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 81 (see FIGS. 6 and 7). The pressure accumulator 7 stores the fuel supplied from the high-pressure fuel pump 81 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 75 of the connecting pipe connected to 81 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. 8). 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 FIGS. 6 and 7, the high-pressure fuel pump 81 is disposed further on the front side of the engine 1 than the front side housing 5. The high-pressure fuel pump 81 covers the front side of the engine 1. It is being fixed with respect to the front cover 84 attached so. The high-pressure fuel pump 81 is a reciprocating drive type pump having a plunger, and is directly driven by the eccentric shaft 6. A roller lifter 82 that is pressed against a pump drive cam 83 described later is attached to the protruding end of the plunger. The roller lifter 82 includes a roller that abuts on the outer peripheral surface of the pump drive cam 83 and rolls on the outer peripheral surface at the tip thereof. The roller reduces the frictional resistance with the pump drive cam 83. The roller lifter 82 is pressed and urged toward the pump drive cam 83 by a compression spring. As a result, the roller always contacts the outer peripheral surface of the pump drive cam 83 and rolls on the outer peripheral surface.

  The pump drive cam 83 is fitted on the eccentric shaft 6 and is fixed to the eccentric shaft 6 so as to rotate together. As shown in FIG. 7, the pump drive cam 83 has two cam ridges, and the two cam ridges are arranged at intervals in the circumferential direction by 180 °. As the eccentric shaft 6 rotates, the pump drive cam 83 rotates, and the plunger of the high pressure fuel pump pressed against the pump drive cam 83 is attached with a compression spring each time the cam crest of the pump drive cam 83 passes. It is pushed into the high-pressure fuel pump 81 against the force. As a result, the high-pressure fuel pump 81 pumps the fuel supplied from a fuel tank (not shown) toward the pressure accumulator 7. Since the high pressure fuel pump 81 is a reciprocating drive type, fuel is intermittently pumped, while the pump drive cam 83 has two cam peaks, so the high pressure fuel pump 81 rotates twice for each rotation of the eccentric shaft. Perform pumping.

  Here, the high-pressure fuel pump 81 has a region on the side where the intake ports 11, 12, 13 and the exhaust port 10 are formed across the long axis Y when viewed in the rotation axis X direction shown in FIG. Of the region on the side where the spark plugs 91 and 92 are disposed, the region on the side where the spark plugs 91 and 92 are disposed and the injectors 15 and 16 are disposed across the minor axis Z. The region on the opposite side and the region on the opposite side are disposed in the region on the side where the injectors 15 and 16 are disposed. That is, it is disposed in the upper right region (region approximately corresponding to the compression stroke) in FIG. Thus, the reciprocating direction of the plunger of the high-pressure fuel pump 81 is a direction inclined with respect to the major axis Y and the minor axis Z, and this direction is generally the upper right region (the compression stroke region in FIG. 7). ) To the lower left region (exhaust stroke region). The arrangement of the high-pressure fuel pump 81 has an advantage that it is hardly affected by the bending of the eccentric shaft 6. That is, due to the combustion of the air-fuel mixture in the compression / expansion working chamber 8, the eccentric shaft 6 is subjected to the upper right region (intake stroke region) from the lower right region (expansion stroke region) as shown by the arrow in FIG. The load in the diagonal direction to reach the area of (). The eccentric shaft 6 receives a load accompanying this combustion, and is bent in the direction of the arrow in FIG. The reciprocating direction of the plunger of the high-pressure fuel pump 81 is substantially orthogonal to the bending direction. If the reciprocating direction of the plunger is set to the same direction as the bending direction, when the eccentric shaft 6 is bent, the roller lifter 82 and the pump drive cam 83 may be separated or hit, There is a risk that abnormal noise may be generated or the roller lifter 82 or the pump drive cam 83 may be worn. On the other hand, when the reciprocating direction of the plunger of the high-pressure fuel pump 81 is substantially orthogonal to the bending direction of the eccentric shaft 6, it is not affected by the bending of the eccentric shaft 6.

  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. 8 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 having the above-described configuration 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 a range of about −450 ° to about −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 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. 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 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 about −180 ° to about −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. When the rotary piston engine 1 shifts from the intake stroke to the compression stroke as the rotor 2 rotates, the flow of the air-fuel mixture (fuel) is relatively delayed with respect to the rotation of the rotor 2, and as a result, the rotor 2 In the compression / expansion working chamber 8 having a flat shape in the rotational direction, the region on the relatively leading side in the rotor rotational direction becomes lean and the region on the lagging side in the rotor rotational direction becomes relatively rich. Cause heterogeneity. 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.

  As shown by an asterisk in FIG. 9, the high-pressure fuel pump 81 pumps fuel approximately at the ignition timing. As described above, since the pump drive cam 83 has two cam peaks, the fuel is pumped once for every 180 ° of the eccentric angle. After the fuel is pumped once, the second injector 16 attached to the front or rear rotor housing 3 among the four injectors 15 and 16 connected to the pressure accumulator 7 is first operated in a predetermined manner. Compression injection is performed in the chamber 8. Next, the first injector 15 attached to the rotor housing 3 performs the intake counter-injection in the working chamber 8 which is the next intake stroke (see the arrow in FIG. 9). A specific example will be described. After the fuel pumping is performed once at an exhaust angle of about 360 ° in FIG. 9, in the front side chamber within an angular range of about 360 ° to about 450 °. When the compression injection is performed, the intake air facing injection is then performed in the two front chambers in an angle range of about 450 ° to about 550 °. Thus, two fuel injections are performed in the order of the compression injection and the intake air opposed injection for one fuel pumping of the high-pressure fuel pump 81.

  Here, the fuel pressure fluctuation in the pressure accumulator 7 shown in FIG. 9 is referred to. When the high-pressure fuel pump 81 performs fuel pumping, the pressure in the accumulator 7 is increased by a corresponding amount. Thereafter, a relatively small amount of compression injection is performed, so that the fuel pressure is decreased by a relatively small decrease amount (ΔP1) corresponding to the injection amount, and then a relatively large amount of intake air is opposed. By performing the injection, the fuel pressure is decreased by a relatively large decrease amount (ΔP2) by an amount corresponding to the injection amount. Then, after the two fuel injections, the fuel pressure in the pressure accumulator 7 is recovered by the high-pressure fuel pump 81 performing fuel pumping again. Thus, since the compression injection is performed with the fuel pressure in the accumulator 7 being the highest, good spray characteristics are required due to the high pressure in the working chamber 8 and the short vaporization atomization time. Can be reliably performed. Since the compression injection has a small injection amount, the amount of decrease in the fuel pressure in the accumulator 7 is small. For this reason, it is possible to perform subsequent intake counter-injection while maintaining a relatively high fuel pressure. This improves the spray characteristics of the intake air opposed injection and is effective in terms of fuel vaporization and atomization. That is, after the fuel is pumped by the high-pressure fuel pump 81, performing the compression injection with a small injection amount first can not only perform the compression injection well, but also suppress the decrease in the fuel pressure in the accumulator 7. This is also effective in that the next intake counter-injection can be performed satisfactorily.

  For example, the number of cam peaks of the pump drive cam 83 can be increased, and the high pressure fuel pump 81 can be driven each time the first or second injector 15 or 16 performs fuel injection, for example. However, the increase in the number of times the high-pressure fuel pump 81 is driven increases the driving resistance with respect to the engine speed, which is disadvantageous in terms of fuel consumption. Therefore, reducing the number of times the high-pressure fuel pump 81 is driven is advantageous for improving fuel efficiency. For example, the number of cam ridges of the pump drive cam 83 can be reduced to, for example, one. In this case, four fuel injections are performed for one drive of the high-pressure fuel pump 81. However, excessively reducing the number of times the high-pressure fuel pump 81 is driven can reduce the startability of the engine 1. That is, when the engine 1 is started, the fuel pressure in the accumulator 7 must be increased from a low state to a predetermined pressure. This is because when the fuel pressure in the pressure accumulator 7 is equal to or lower than a predetermined pressure, a desired amount of fuel cannot be injected through the injectors 15 and 16 and the spray characteristics are extremely poor. Therefore, there is a demand for increasing the fuel pressure in the accumulator 7 as early as possible. However, if the pump drive cam 83 has only one cam crest, the high pressure fuel pump 81 is not driven unless the eccentric shaft rotates once. Things can happen. For this reason, the pressure increase in the pressure accumulator 7 is delayed, and there is a possibility that the standby time until fuel injection, and thus the start time of the engine 1 will become longer. On the other hand, when the number of cam crests of the pump drive cam 83 is two, the high pressure fuel pump 81 is always driven if the eccentric shaft 6 rotates at least half a turn. This can accelerate the pressure increase in the pressure accumulator 7 and shorten the waiting time until fuel injection, and thus the start time of the engine 1. This enhances the merchantability of an automobile equipped with the engine 1.

  Here, referring to FIG. 10, the heat generation pattern of the rotary piston engine 1 having the first and second injectors 15 and 16 (see the solid line in the embodiment) and the conventional configuration for performing the intake port injection. 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. That is, in the compression / expansion operation chamber, the heterogeneity that the leading side in the rotor rotation direction becomes relatively lean and the delay side in the rotor rotation direction becomes relatively rich, and the flame generated by ignition of the spark plug, Combustion of conventional rotary piston engines is combined with the flame propagation characteristics unique to rotary piston engines that are easy to propagate to the leading side in the rotor rotation direction due to the flow in the working chamber and difficult to propagate to the delay side in the rotor rotation direction. In the pattern, after main combustion occurs on the leading side in the rotor rotation direction and on the relatively lean side, late combustion occurs on the delay side in the rotor rotation direction and on the relatively rich side. This is the stage combustion characteristic.

  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. 11 shows a modification related 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. 11, 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. 12 shows a modification related to 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 distances between the injectors 15 and 16 through the first and second fuel supply pipes 71 and 72 and the communication pipe 77 are equal, the fuel injection amount of each injector 15 and 16 is The error is equal.

  In this pressure accumulator 7, the other end of the first fuel supply pipe 71 is attached to the other end (the left end in FIG. 12) of the connecting pipe connected to the high pressure fuel pump, and the other end of the second fuel supply pipe 72. 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 (the number of cylinders) is not limited to this.

  This technique is not limited to application to a rotary piston engine, but can also be applied to a reciprocating engine. Next, the present technology will be described by taking a four-cylinder in-line engine in which first to fourth four cylinders are arranged in series as an example. Note that the number of cylinders and their arrangement in the reciprocating engine are not limited.

  Since the basic configuration of a four-cylinder in-line engine is well known, its illustration is omitted here. Each cylinder has an intake port opened and closed by an intake valve and an exhaust port opened and closed by an exhaust valve. Each of the intake valve and the exhaust valve is driven by a cam shaft (cam shaft) in which a valve opening / closing cam is provided integrally with rotation. The valve opening / closing cam directly or indirectly acts on the intake valve or the exhaust valve, and opens and closes the intake valve or the exhaust valve at a predetermined timing. The camshaft may be provided individually for each of the intake valve and the exhaust valve, or may be provided in common. The camshaft is drivingly connected to the crankshaft of the engine and is driven to rotate so as to make one rotation for one cycle of the cylinder.

  One injector is attached to each cylinder. The engine therefore has four injectors. Each of the four injectors is connected to a pressure accumulator. Each injector may inject fuel directly in each cylinder during the intake stroke and during the compression stroke in accordance with the operating region of the engine (this makes weak stratified combustion possible). In this case, each injector performs fuel injection twice per cycle. Here, it is desirable that the fuel injection amount during the compression stroke is smaller than the fuel injection amount during the intake stroke.

  In this engine, the pump driving gum is attached to the camshaft so as to rotate integrally. Since the pump drive cam has the same number of cam peaks as the number of cylinders, it has four cam peaks in this example. Therefore, the high-pressure fuel pump driven by this pump drive cam reciprocates four times for each rotation of the camshaft. Since it is desirable that the four cam peaks are arranged at equal intervals, it is preferable that the cam peaks are arranged at 90 ° intervals. Further, in the camshaft, it is desirable that the phase of the pump drive cam is shifted from the phase of the valve opening / closing cam. Thereby, it is possible to avoid the drive reaction force and the valve reaction force of the high-pressure fuel pump from acting on the camshaft simultaneously.

  FIG. 13 shows a timing chart of the 4-cylinder in-line engine. In the four-cylinder in-line engine, the combustion cycle shifts in the order of the first, third, fourth, and second. In FIG. 13, the cylinders are arranged in order from the top so as to be in the order of transition of the cycle. Further, in the figure, the mountain-shaped curve shown in the “intake” column shows an example of the lift curve of the intake valve. That is, it corresponds to the profile of each valve opening / closing cam in the camshaft. The lift curve shown here is merely an example, and does not define the opening timing and closing timing of the intake valve. Moreover, the column of the pump drive cam in FIG. 13 shows an example of the cam profile of the pump drive cam. As described above, since the pump drive cam has four cam peaks, it has four peaks per rotation of the camshaft. At each peak, the high pressure fuel pump pumps the fuel. Therefore, in this engine, fuel is pumped four times for one rotation of the camshaft. The amount of phase shift between the pump drive cam and the valve opening / closing cam is not limited to the amount shown in FIG. The amount of phase shift between both cams can be set as appropriate.

  In contrast to the high pressure fuel pump pumping fuel once, fuel injection is performed twice. Of the two fuel injections, the first fuel injection is performed during a compression stroke in a predetermined cylinder. Thus, the next fuel injection is performed during the intake stroke in a cylinder different from the predetermined cylinder (see the arrow in FIG. 13). Explaining with a specific example, after one fuel pressure feed is performed at a cam angle of about 90 ° in FIG. 13, within the angle range of about 90 ° to about 180 °, the first cylinder performs the compression stroke. When injection is performed, injection is then performed during the intake stroke in the fourth cylinder in an angular range of about 180 ° to about 270 °. Thus, two fuel injections are executed for one fuel pumping of the high-pressure fuel pump. Thus, the driving resistance of the high-pressure fuel pump can be reduced even in a reciprocating engine.

  Further, as described above, by performing the fuel injection during the compression stroke first of the two fuel injections, the fuel injection satisfying the high spray characteristic requirement becomes possible. Since the amount of fuel injection during the compression stroke is relatively small, the decrease in the fuel pressure in the accumulator is small, and the fuel pressure can be kept relatively high. In this state, by performing fuel injection during the intake stroke, good spray characteristics can be obtained, and fuel atomization can be improved. Therefore, also in the reciprocating engine, the improvement in fuel vaporization and atomization and the suppression of the driving resistance of the fuel pump can be achieved at the same time, thereby improving the fuel efficiency.

  As described above, this technique is useful for improving the fuel efficiency of a direct injection 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 longitudinal cross-sectional view of the engine which shows arrangement | positioning of a high pressure fuel pump. It is a transverse cross section of an engine which shows arrangement of a high-pressure fuel pump. 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. It is a timing chart regarding operation of a reciprocating engine.

1 Rotary piston engine (direct injection engine)
11 Intake port 15 1st injector (1st fuel injection valve)
16 Second injector (second fuel injection valve)
2 Rotor 31 Rotor housing chamber 6 Eccentric shaft 8 Working chamber 81 High-pressure fuel pump 83 Pump drive cam

Claims (5)

An engine body having at least one cylinder that sequentially repeats intake, compression, expansion, and exhaust strokes;
A fuel injection valve for directly injecting fuel into the cylinder;
An accumulator to which the fuel injection valve is connected and which supplies high-pressure fuel to the fuel injection valve;
A reciprocating drive type fuel pump that boosts the fuel pressure in the accumulator by intermittently pumping fuel to the accumulator along with the reciprocating drive;
The engine body has a plurality of cylinders that perform each of the strokes in different phases,
One fuel injection valve is disposed in each cylinder, and each fuel injection valve is connected to the pressure accumulator,
The fuel injection valve is configured to inject the fuel into the cylinder at each timing when the cylinder is in an intake stroke and when it is in a compression stroke,
The engine body is different from the specific cylinder after the fuel injection valve of the specific cylinder injects fuel in the specific cylinder in the compression stroke , whereas the fuel pump performs fuel pumping once . A fuel injection device for a direct injection engine configured to inject the fuel twice by a fuel injection valve of a cylinder in the intake stroke . An engine body having at least one cylinder that sequentially repeats intake, compression, expansion, and exhaust strokes;
A fuel injection valve for directly injecting fuel into the cylinder;
An accumulator to which the fuel injection valve is connected and which supplies high-pressure fuel to the fuel injection valve;
A reciprocating drive type fuel pump that boosts the fuel pressure in the accumulator by intermittently pumping fuel to the accumulator along with the reciprocating drive;
The engine body includes a rotor housed in a rotor housing chamber to divide three working chambers, and the rotor rotates planetarily around an output shaft, thereby moving each working chamber in the circumferential direction while A rotary piston engine having a cylinder configured to cause each of the compression, expansion and exhaust strokes to be performed in order,
The fuel injection valve is disposed in the first and second two with respect to the cylinder, and the first and second fuel injection valves are connected to the pressure accumulator, respectively.
In the rotary piston engine, the first fuel injection valve injects fuel when the working chamber is in the intake stroke, and the second fuel injection valve injects fuel when the working chamber is in the compression stroke. The fuel pump is configured to inject fuel once, whereas the second fuel injection valve injects fuel in the specific working chamber in the compression stroke, whereas the fuel pump performs fuel pumping once. On the other hand, the first fuel injection valve injects fuel when the next working chamber is in the intake stroke, so that the fuel is injected twice through the first and second fuel injection valves. Fuel injection system for direct injection engines. The fuel injection device for a direct injection engine according to claim 2 ,
The fuel pump is driven to reciprocate by a pump drive cam that rotates as the engine body operates.
The rotary piston engine has a plurality of cylinders configured to include a rotor accommodating chamber and a rotor supported to perform planetary rotation with respect to the eccentric shaft while being accommodated in the rotor accommodating chamber,
The pump drive cam is provided on the eccentric shaft,
The fuel injection device for a direct injection engine , wherein the number of cam ridges of the pump drive cam is set to be equal to the number of cylinders of the rotary piston engine . An engine body having at least one cylinder that sequentially repeats intake, compression, expansion, and exhaust strokes;
A fuel injection valve for directly injecting fuel into the cylinder;
An accumulator to which the fuel injection valve is connected and which supplies high-pressure fuel to the fuel injection valve;
A reciprocating drive type fuel pump that boosts the fuel pressure in the accumulator by intermittently pumping fuel to the accumulator along with the reciprocating drive;
The engine body is a reciprocating engine having a plurality of cylinders each provided with intake and exhaust valves.
The fuel injection valve is configured to inject the fuel into the cylinder at each timing when the cylinder is in an intake stroke and when it is in a compression stroke,
The engine body injects fuel twice through the fuel injection valve in the order of fuel injection during the compression stroke and fuel injection during the intake stroke, whereas the fuel pump performs fuel pumping once. Configured as
The fuel pump is provided on a camshaft that opens and closes the intake and exhaust valves, and is reciprocated by a pump drive cam that rotates with the operation of the engine body.
The number of cam ridges of the pump drive cam is set to be the same as the number of cylinders the engine body has,
A fuel injection device for a direct injection engine , wherein a phase angle of a valve opening / closing cam provided on the cam shaft and a phase angle of the pump drive cam are deviated from each other . In the fuel-injection apparatus of the direct-injection engine of any one of Claims 1-4,
A fuel injection device for a direct injection engine , wherein a fuel injection amount during the compression stroke is smaller than a fuel injection amount during the intake stroke .

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