JP2007051549A - Fuel injection valve and direct injection engine provided with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection valve and a direct injection engine provided with it for satisfying spray characteristics required respectively in operations of stratified-charge combustion and homogenous combustion. <P>SOLUTION: The direct injection engine comprises a fuel-injection valve 10, a mixture formation-control mechanisms 102, 103, and a control means 100. The fuel injection valve 10 has two superimposable sheets of orifice plates 1, 2 in which a plurality of nozzle holes 1a, 1b, 2a, 2b are formed respectively in specified orientation, and by rotating or moving one plate 2 relative to the other plate 1, at least one of the shape of the nozzle hole, the number of nozzle-holes to be opened, the nozzle-hole sectional-area, and the direction of the nozzle holes is constituted to be changeable. The mixture formation-control mechanisms 102, 103 conduct stratification of the air-fuel mixture, and formation of homogeneous mixture and the like, the control means 100 controls the fuel-injection valve 10 and the mixture formation-control mechanism 103. On the basis of operating conditions, the control means 100 changes at least one of the shape of the nozzle holes, the number of nozzle holes to be opened, the sectional area of the nozzle holes, and the direction of the nozzle holes so as to change characteristics such as the fuel-spray pattern, the injection rate, etc. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel injection valve, and more particularly, to a fuel injection valve having one or a plurality of injection holes for directly injecting fuel into a combustion chamber, and a cylinder injection engine having the same.

  2. Description of the Related Art Conventionally, in-cylinder spark ignition gasoline engines that inject fuel directly into a combustion chamber are widely known. In this in-cylinder injection type engine, so-called stratified combustion operation is performed, in which the air-fuel mixture in the combustion chamber is unevenly distributed in the vicinity of the spark plug, mainly at low loads and at start-up, thereby reducing pumping loss and improving fuel efficiency. Various techniques have been developed to improve exhaust purification performance (exhaust emission characteristics) by operating in a so-called retarded state, or by retarding the ignition timing.

  In such an in-cylinder injection engine, in general, the stratified charge combustion operation and the homogeneous combustion operation performed at a higher load or after the engine warm-up are different from each other in ideal fuel spray characteristics. It is said that it is necessary to form a fuel spray corresponding to each.

In relation to this, for example, in Patent Document 1 below, in a combustion chamber of a two-stroke engine, a first fuel injection valve (injector) for stratified combustion operation and a second fuel injection valve (injector) for homogeneous combustion operation are disclosed. And a direct injection engine that selectively injects fuel from one of the fuel injection valves according to the operating state of the engine. In such an engine, during stratified combustion operation, fuel is injected only from the first fuel injection valve so that an air-fuel mixture exists only in the vicinity of the spark plug, and during homogeneous combustion operation, fuel spray and combustion from the second fuel injection valve are performed. Facing the scavenging air in the room promotes mixing of fuel and air. As a result, good combustion can be obtained over a wide operating range of the engine.
Japanese Patent Laid-Open No. 7-247841

  However, in the configuration in which two fuel injection valves are provided in one cylinder (combustion chamber) as in the engine described in Patent Document 1, the cost is higher than in the case of one fuel injection valve. In addition, there is a problem that it is difficult to secure a space for the fuel injection valve and the high-pressure fuel pipe, particularly in an in-cylinder in-cylinder injection engine.

  On the other hand, in order to increase the efficiency of the stratified operation, it is necessary to reduce the pumping loss by reducing the fuel injection amount and increasing the air-fuel ratio. If two fuel injection valves are used as in the conventional example, this can be achieved by lowering the injection rate of the stratified fuel injection valve. However, as described above, the two fuel injection valves have problems of cost and space. Therefore, if this is done with a single fuel injection valve, the fuel flow rate at the maximum torque must be able to be supplied while covering the minimum injection amount during the stratified operation, which increases the dynamic range of the fuel injection valve. Therefore, there is a problem that a minute fuel injection amount cannot be supplied with high accuracy, or a large flow rate cannot be satisfied.

  The present invention has been made to solve the conventional problems as described above, and the object of the present invention is to perform the stratified charge combustion operation while keeping the cost low and without requiring a large space around the engine. Satisfying the required spray characteristics at the time of combustion and homogeneous combustion operation, and furthermore, a sufficient amount of fuel can be supplied at high load, while a small amount of fuel can be accurately supplied at low load. An object of the present invention is to provide a fuel injection valve capable of improving emission characteristics and the like, and a cylinder injection engine provided with the same.

  In order to achieve the above object, the fuel injection valve according to the present invention basically has two orifice plates each having a plurality of injection holes that can be overlapped with each other in a predetermined arrangement state, By rotating or moving one plate with respect to the other plate, at least one of the shape of the nozzle hole, the number of nozzle holes to be opened, the nozzle hole cross-sectional area, and the direction of the nozzle hole can be changed. It becomes.

  Below, the preferable aspect of the fuel injection valve which concerns on this invention is enumerated.

  A vane mechanism is provided that rotates one plate relative to the other plate using the pressure of the fluid.

  The vane mechanism rotates one plate with respect to the other plate using the pressure of the fuel supplied into the valve.

  A stepping motor is provided for rotating one plate relative to the other plate.

  The vane mechanism or the stepping motor is disposed between the valve drive coil and the plate.

  The arrangement mode of the nozzle holes of one orifice plate is different from the arrangement mode of the nozzle holes of the other orifice plate.

  The sectional area or diameter of the nozzle hole of one orifice plate is made larger than the sectional area or diameter of the nozzle hole of the other orifice plate.

  At least one of the two orifice holes of the two orifice plates has a long hole shape formed by an arc having the same distance from the center.

  The two orifice plates have conical surfaces that slidably contact each other, and the nozzle holes are opened in the conical surfaces.

  The nozzle hole is inclined outward with respect to the central axis.

  On the other hand, the in-cylinder injection engine according to the present invention includes the above-described fuel injection valve, an air-fuel mixture generation control mechanism for stratifying the air-fuel mixture, generating a homogeneous air-fuel mixture, the fuel injection valve, and the mixing Control means for controlling the air generation regulating mechanism.

  Then, the control means changes at least one of the shape of the nozzle hole, the number of nozzle holes to be opened, the nozzle hole cross-sectional area, and the direction of the nozzle hole based on the operating state, thereby changing the shape of the fuel spray, the injection The characteristics such as rate are changed.

  In this case, the fuel injection valve is preferably provided sideways on the intake passage side in the combustion chamber.

  The air-fuel mixture generation control mechanism is preferably disposed at a partition plate that divides the downstream passage portion of the intake passage into an upper passage portion and a lower passage portion, and an upstream end portion of the lower passage portion. And an intake control valve that selectively opens and closes the lower passage portion.

  In another preferable aspect, the fuel injection valve provided with the vane mechanism that rotates one plate with respect to the other plate using the pressure of the fuel supplied into the valve is provided, and the control unit includes: By increasing or decreasing the fuel pressure during the stratified combustion operation and by decreasing or increasing the fuel pressure during the homogeneous combustion operation, characteristics such as the shape of the fuel spray and the injection rate are changed.

  In a further preferred aspect, the control means performs fuel injection in a plurality of times for each combustion cycle.

  In the fuel injection valve according to the present invention and the direct injection gasoline engine having the same, the following operational effects can be obtained.

  First, since fuel is injected only from the nozzle holes formed in the two orifice plates, the fuel mixture is distributed according to each of the stratified combustion operation and the homogeneous combustion operation. Can do.

  Also, by reducing the nozzle diameter or reducing the number of nozzles that are opened, etc., even if the same fuel injection pulse width and the same fuel pressure are used, the total nozzle cross-sectional area decreases and the flow rate (injection amount) decreases. . Thereby, the fuel injection rate can be reduced without reducing the pulse width.

  Furthermore, the mixture distribution can be further optimized by combining with split injection.

  From the above effects of the fuel injection valve, the air-fuel ratio at the time of stratified combustion operation can be reduced, the pumping loss can be reduced, and the adhesion of fuel spray to the wall surface can be reduced to reduce unburned hydrocarbons. it can.

  In addition, while having the above features, there is an effect that the air utilization rate can be increased and a high output can be obtained at a high load. This effect is the same when split injection is performed in the intake stroke.

  Further, when the engine is cold, there is little fuel adhering to the piston and the combustion chamber wall surface, and afterburning combustion is performed by split injection or the like, so that the activation of the catalyst can be accelerated and the exhaust emission characteristics can be improved.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a fuel injection valve and an in-cylinder injection engine of the present invention will be described with reference to the drawings.

  FIG. 1 and FIG. 2 are a schematic side view and a schematic plan view, respectively, showing an embodiment of a direct injection engine according to the present invention.

  The illustrated in-cylinder injection engine 90 is an in-vehicle in-line four-cylinder engine, for example, and is slidably fitted into a cylinder 92 and each cylinder of the cylinder 92 (only one cylinder is shown). And a combustion chamber 95 is defined above the piston 107. A spark plug 113 is erected on the top of the combustion chamber 95, and a fuel injection valve 10 for injecting fuel directly into the combustion chamber 95 is laid sideways on the intake passage (intake port) 101 side. (Details later).

  Air to be used for fuel combustion is taken in from an air cleaner 106 provided at the start end of the intake passage 101, passes through an air flow sensor 105, passes through an electric throttle valve 108, and enters a collector 116. The air is sucked into the combustion chamber 95 through the downstream passage portion (intake pipe, intake port) 101A of the intake passage 101 and the intake valve 111 disposed at the downstream end thereof.

  The air-fuel mixture of the air sucked into the combustion chamber 95 and the fuel injected from the fuel injection valve 10 is ignited by the spark plug 113 and explosively burned, and the combustion waste gas (exhaust gas) passes through the exhaust valve 112. The exhaust gas is discharged to the exhaust passage 110, purified by the three-way catalyst 115 disposed in the exhaust passage 110, and then discharged to the outside through the silencer 117.

  A downstream passage portion (intake pipe, intake port) 101A of the intake passage 101 is divided into an upper passage portion 101a and a lower passage portion 101b by a partition plate 102, and an upstream end portion of the lower passage portion 101b. Is provided with an intake control valve 103, which selectively opens and closes the lower passage portion 101b.

  In the in-cylinder injection engine 90 of the present embodiment, a control incorporating a microcomputer is performed to control each part of the engine 90 including the fuel injection valve 10, the spark plug 113, the intake control valve 103, and the throttle valve 108. A unit 200 is provided.

  The control unit 200 is well known per se, and is composed of an MPU, EP-ROM, RAM, I / O LSI including an A / D converter, etc., and is detected by an airflow sensor 105 as an input signal. In addition to a signal corresponding to the amount of intake air to be transmitted, a signal corresponding to the opening of the throttle valve 108 detected by the throttle sensor 104, a signal indicating the rotational speed of the crankshaft from the crank angle sensor 97, that is, the engine speed, Although not shown, a signal corresponding to, for example, the oxygen concentration in the exhaust gas detected by the air-fuel ratio sensor provided in the exhaust passage 110, and the engine cooling water temperature detected by the water temperature sensor provided in the cylinder 92. Corresponding signal, signal indicating start of start (cranking start) from ignition switch, accelerator sensor A signal indicating a depression amount of an accelerator pedal obtained al, signals and the like corresponding to the running speed of the vehicle obtained from the vehicle speed sensor is also provided.

  The control unit 200 fetches each signal with a predetermined period, executes a predetermined calculation process, and uses the control signal calculated as the calculation result as the fuel injection valve 10, the spark plug 113, the intake control valve 103, the electric control valve. The fuel is supplied to the throttle valve 108 and the like, and fuel injection (injection amount, injection timing, number of injections) control, ignition timing control, opening control of the intake control valve 103, opening control of the throttle valve 108, and the like are executed.

  Here, for example, when it is determined that the engine is in a low load state during normal traveling, the control unit 200 controls the opening degree of the intake control valve 103 so as to obtain a more optimal tumble strength. Basically, the intake control valve 103 is fully closed to perform stratified combustion operation at low fuel pressure, and the intake control valve 103 is opened to perform homogeneous combustion operation at high fuel pressure. Further, fuel injection is performed in the latter half of the compression stroke, for example, 40 degrees before the top dead center.

  FIG. 3 is a longitudinal sectional view showing an example of a fuel injection valve used in the engine 90 of the present embodiment, and FIG. 4 is an enlarged cross section showing a lower end portion (a nozzle peripheral portion) of the fuel injection valve 10 shown in FIG. FIG.

  In the fuel injection valve 10 shown in FIGS. 3 and 4, the fuel F is supplied from above. The joint between the fuel injection valve 10 and the fuel pipe (not shown) is sealed by an O-ring 9A and a backup ring 9B. The fuel F passes through the portion of the core 12 and the spring 11, passes through the hole 8 a drilled in the plunger rod 8, and then passes between the plunger rod 8 and the inner holder 4 toward the bottom.

  When a voltage is applied to the electrode 20 according to a command (pulse signal) from the control unit 200, the coil 15 is excited, and the plunger rod 8 below the yoke 14 and the core 12 overcomes the biasing force of the spring 11. Pulled up. As a result, as shown in FIG. 4, the fuel F has a gap formed between the lower end (conical surface) of the plunger rod 8 and the conical inner orifice plate 2, and a nozzle formed in the inner orifice plate 2. 2a, 2b (described later), pressures in the combustion chamber 95 through the nozzle holes 1a, 1b (described later) formed in the outer orifice plate 1 having a conical surface on which the inner orifice plate 2 is slidably contacted. It is atomized by the difference and sprayed in the form of a mist.

  The inner orifice plate 2 is integrated with a stepped cylindrical inner holder 4, and a movable vane 6 is integrated with the upper portion of the inner holder 4. The outer orifice plate 1 is integrated with the outer holder 3, and the outer holder 3 is press-fitted and fixed to the housing 16. An inner holder 4 and an inner orifice plate 2 are inserted into the outer holder 3 and the outer orifice plate 1 so as to be able to rotate and slide. Note that a tip seal 5 is attached to the outer holder 3 in order to prevent gas from blowing through the combustion chamber 95.

  5 and 6 show first modes of the nozzle holes 1a and 1b of the outer orifice plate 1 and the nozzle holes 2a and 2b of the inner orifice plate 2, respectively (a bottom view and a bottom perspective view of FIG. 3). The outer orifice plate 1 has a laminar injection hole 1a having a circular cross section on one side in the front-rear direction (upper side in FIG. 5) and the other side from the center in the front-rear direction (lower side from the center in FIG. 5). .., Five homogenous nozzles 1b, 1b,... Having a circular cross section are formed at equiangular intervals on the same circumference. On the other hand, the inner orifice plate 2 is formed with an arcuate stratification nozzle hole 2a that is long in the circumferential direction on one side in the front-rear direction (upper side in FIG. 6) and from the center to the other side (in FIG. 6). .. Are formed at equal angular intervals on the uniform circumference from the center to the lower side).

  The center positions of the nozzle holes 1a, 1b, 1b,..., 2a, 2b, 2b,... Are arranged so that the distances from the common plate center (center axis O) are substantially the same. The nozzle holes 1a and 2a and the nozzle holes 1b, 1b, ... and 2b, 2b, ... are overlapped at a reference position (position shown in Figs. 5 and 6). Here, the diameter or circumferential width of the nozzle holes 1a and 1b is made smaller than the diameter or circumferential width of the nozzle holes 2a and 2b. After being squeezed by 2b, it is further squeezed by the nozzle holes 1a and 1b. Further, each of the nozzle holes 1a, 1b, 2a, and 2b is opened perpendicularly to the conical surface, that is, inclined outward with respect to the central axis O.

  7 and 8, the outer orifice plate 1 in which the nozzle holes 1 a and 1 b are formed, the outer holder 3, the inner orifice plate 2 in which the nozzle holes 2 a and 2 b are formed, the inner holder 4, the movable vane 6, and the like. The state of operation of the spray variable mechanism is shown. FIG. 7 shows a state during stratified combustion operation, and FIG. 8 shows a state during homogeneous combustion operation. In these drawings, the main parts are drawn as a plan perspective view of FIG. 3 in order to easily show the state of operation.

  7 and 8, the inner orifice plate 2 and the movable vane 6 are integrated, and four movable vanes 6 are provided at equal angular (90 °) intervals along the circumferential direction. Between the adjacent movable vanes 6-6, four fixed vanes 7 are provided at equiangular (90 °) intervals, and a vane spring 21 is disposed between the movable vanes 6 and the fixed vanes 7. Yes.

  At the time of the stratified combustion operation shown in FIG. 7, the movable vane 6 rotates counterclockwise in the drawing by the force that the vane spring 21 tries to extend, and stops with the gap 22 remaining between the movable vane 6 and the fixed vane 7. At this time, since the nozzle hole 2a, which is an arc-shaped long hole, is located on the nozzle hole 1a, the nozzle hole 1a is opened, but is separated from the nozzle hole 1b and the nozzle hole 2b. The fuel cannot be injected. That is, fuel is injected only from one stratification nozzle 1a, 2a. As a result, as shown in FIG. 9, the fuel can be distributed only in the vicinity of the spark plug 113 and the stratification degree of the air-fuel mixture can be increased (described later).

  On the other hand, during the homogeneous combustion operation shown in FIG. 8, a fuel F having a higher fuel pressure than that during the stratified combustion operation is supplied from a high pressure pump (not shown). As a result, the movable vane 6 overcomes the force that the vane spring 21 tries to extend, rotates clockwise, and stops at a position that balances with the spring force. At this time, since the nozzle hole 2a which is an arc-shaped long hole is located on the nozzle hole 1a, the nozzle hole 1a is opened, and furthermore, the five nozzle holes 1b and the five nozzle holes 2b overlap each other. Open and eventually fuel is injected using six nozzles. As a result, as shown in FIG. 10, the fuel is distributed in the vertical direction of the combustion chamber 95, and uniform spraying can be achieved (described later).

  FIG. 9 shows the combustion chamber 95 and its surroundings when the piston 107 is in the compression stroke during the stratified combustion operation. After the intake stroke, the intake valve 111 is closed, and when the compression stroke is entered, the intake air is compressed by the rise of the piston 107. At this time, as described above, fuel is injected from the fuel injection valve 10 only from the stratification nozzle 1a toward the spark plug 113 to form one spray 125, and then mixed in the vicinity of the spark plug 113. Qi is generated. This makes it possible to stably perform ignition combustion while reducing the pumping loss by inhaling a large amount of air even at low load, enabling efficient combustion while suppressing misfire and combustion fluctuation become. Further, the fuel does not adhere to the piston 107 or the combustion chamber wall, and the discharge of unburned hydrocarbon (HC) can be suppressed.

  FIG. 10 shows the combustion chamber 95 and its surroundings when the piston 107 is in the intake stroke during the homogeneous combustion operation. During a medium load or a high load, a homogeneous combustion operation is performed, and fuel is injected in the intake stroke. In the intake stroke, the piston 107 is lowered, the intake valve 111 is opened, and air flows from the intake passage 101 into the combustion chamber 95. The exhaust valve 112 is closed. At this time, as described above, fuel is injected from the stratified injection hole 1a and the five homogeneous injection holes 1b from the fuel injection valve 10 to form six sprays 125. Since this spray is wide and widely distributed in the vertical direction of the combustion chamber 95, it is mixed with the air flow 120 from the upper passage portion 101a and the lower passage portion 101b from the intake stroke to the compression stroke, and the air-fuel mixture has high homogeneity. Is generated. As a result, the combustion efficiency and the air utilization rate are increased, and it becomes possible to obtain a high output while improving the fuel efficiency.

  11 and 12 show a second mode of the nozzle holes 1a and 1b of the outer orifice plate 1 and the nozzle holes 2a and 2b of the inner orifice plate 2, respectively. This is substantially the same as the first mode shown in FIGS. 5 and 6, but the nozzle hole 2 a of the inner orifice plate 2 is not circular but has a circular cross section. The nozzle hole 2a is formed at a position overlapping the nozzle hole 1a only during the stratified combustion operation. That is, during the stratified combustion operation, fuel is injected only from the stratification nozzles 1a and 2a as in the first arrangement example, but during the homogeneous combustion operation, it is not injected from the stratification nozzles 1a and 2a. It is injected only from the injection nozzles 1b, 2b. As a result, it is possible to prevent the air-fuel mixture around the spark plug 113 from being too thick or the spark plug 113 from being smoldered by a large amount of spray.

  FIGS. 13 and 14 show third modes of the nozzle holes 1a and 1b of the outer orifice plate 1 and the nozzle holes 2a and 2b of the inner orifice plate 2, respectively. The outline is the same as in the second embodiment, but the diameters of the nozzle holes 2a, 2b of the inner orifice plate 2 are made smaller than the nozzle holes 1a, 1b of the outer orifice plate 1. That is, the fuel is throttled by the nozzle holes 2a and 2b, and the nozzle holes 1a and 1b serve as a guide. With this configuration, deposit components generated around the nozzle holes 2a and 2b are automatically and mechanically removed by the rotation of the inner orifice plate 2, so that stable spray formation with little secular change is performed. Can do.

  FIGS. 15 and 16 show third modes of the nozzle holes 1a and 1b of the outer orifice plate 1 and the nozzle holes 2a and 2b of the inner orifice plate 2, respectively. The outline is the same as in the first embodiment. There are four nozzle holes, one stratification nozzle hole 1a, 2a, two weak stratification nozzle holes 1c, 2c, and one homogeneous nozzle hole 1b, 2b. The nozzle holes 2a, 2b, and 2c of the inner orifice plate 2 are arc-shaped long holes with a long nozzle hole 2a, arc-shaped long holes with a short nozzle hole 2c, and the nozzle hole 2b has a circular cross section. If comprised in this way, according to fuel pressure, ie, the rotational displacement amount of the movable vane 6 shown by FIG. 7, FIG. 8, the number of the nozzles to be used is one for stratification, a total of 3 for stratification and weak stratification. It is possible to change in three ways, a book, and a total of four books plus a homogenous one. As a result, the distribution of the air-fuel mixture in the combustion chamber 95 can be more appropriately present in the vicinity of the spark plug 113 even during medium load.

  FIG. 17 shows a pulse width (duty ratio) of a control signal (pulse signal) supplied to the fuel injection valve 10 at the same fuel pressure with the nozzle holes 1a, 1b, 2a and 2b being the first mode (the present invention). ) Is shown in comparison with a conventional fuel injection valve (conventional example) in which the number of injection holes is unchanged, and FIG. 18 similarly shows the injection holes 1a, 1b, 2a, 2b. Based on the first aspect (the present invention), the change in the fuel injection amount at the same pulse width is shown in comparison with a conventional fuel injection valve (conventional example) in which the number of injection holes is unchanged.

  In general, when the nozzle cross-sectional area is constant, the fuel injection amount is approximately proportional to the 1/2 power of the fuel pressure. Normally, fuel injectors are used in regions where the relationship between the pulse width and fuel flow rate is linear, but when the pulse width becomes smaller, linearity is maintained below a certain value due to the effects of time delay in valve behavior. It ’s gone. This minimum value is called the minimum injection amount. In consideration of atomization of spray and appropriate values of penetration force, there is a minimum value in the fuel pressure, and fuel having the minimum fuel pressure and the minimum pulse width cannot be stably injected.

  Here, in this embodiment, since the injection is performed from only one of the stratification nozzles 1a at the low fuel pressure (5 MPa), the gradient of the fuel injection amount with respect to the pulse width is very gentle as shown in FIG. Therefore, when the minimum injection amount Qmin2 of the present embodiment (the present invention) is compared with the minimum injection amount Qmin1 of the conventional example, Qmin2 is a fraction of Qmin1. Thereby, the controllability in the case of performing the stratified combustion operation is improved, and it is possible to cope with a case where the injection amount of one injection is small, such as divided injection in which the fuel injection is performed a plurality of times for each combustion cycle. Further, at the time of high fuel pressure (10 MPa), an injection amount equivalent to that of the conventional example can be secured, and the demand for high output can be met.

  FIG. 19 shows another example of the fuel injection valve according to the present invention. In contrast to the fuel injection valve 10 shown in FIG. 3 described above, the fuel injection valve 10 ′ of this example includes a stepping motor coil 40 for rotating the inner holder 4 and a stepping motor shaft 41 between the housing 16 and the coil 15. A stepping motor is provided.

  In the in-cylinder injection engine 90 using the fuel injection valve 10 ′ of the present example, the control unit 100 determines whether the stratified combustion operation or the homogeneous combustion operation is performed by the engine speed and the required torque (accelerator pedal depression amount, etc.). Judgment is made and the amount of rotation of the stepping motor shaft 41 is determined. When the stepping motor shaft 41 rotates, the inner holder 4 and the inner orifice plate 2 also rotate accordingly, and the number of nozzles changes due to this rotation. Since the nozzle form is the same as the first to fourth aspects, it is omitted here. When this fuel injection valve 10 'is used, the number of nozzles can be freely selected regardless of the fuel pressure, and for example, injection can be made only from the stratification nozzle 1a at a high load and a high fuel pressure. Combustion efficiency can be improved by atomization.

  FIG. 20 shows an air-fuel mixture distribution in the combustion chamber 95 when split injection is performed at start-up in the cylinder injection engine 90 of the present embodiment. In the illustrated example, injection is performed twice in total, once in the compression stroke and once in the expansion stroke (shown state). The fuel pressure is small, and only one spray 125 is formed from the stratification nozzle 1a. By the compression stroke injection, a combustible air-fuel mixture is generated in the vicinity of the spark plug 113. Thereafter, fuel is also injected during the expansion stroke, and ignition is performed substantially simultaneously. The total air-fuel ratio of the two fuel injections is about 16. As a result, the fuel injected in the second time (expansion stroke) is post-burned, the unburned hydrocarbon (HC) is reduced before the three-way catalyst 115 is warmed up (before activation), and the catalyst 115 is rapidly heated ( Activation) at the same time.

  FIG. 21 shows the state of the air-fuel mixture in the combustion chamber 95 when split injection is performed at high load in the direct injection engine 90 of the present embodiment. The figure shows the second half of the intake stroke, and injection is performed once in the first half of the intake stroke and once in the second half of the intake stroke shown in the figure. The fuel pressure is high, and the shape of the spray 125 is a total of six stratification nozzle holes 1 a and five homogeneous nozzle holes 1 b, has a wide spray angle, and is widely distributed in the combustion chamber 95. By dividing and injecting, the mixture distribution can be made more uniform, while the charging efficiency can be improved by the intake air cooling effect, and a large amount of fuel and air can be sucked into the cylinder to obtain a large torque.

  FIG. 22 shows the operational effects of the present embodiment (the present invention) in comparison with a conventional example. Compared with the conventional example, the stratified combustion operation can be performed reliably and better, so that the air-fuel ratio can be made thin (lean). Therefore, pumping loss can be reduced and fuel consumption can be reduced. Furthermore, since the fuel adhesion to the piston 107 and the combustion chamber wall surface can be suppressed at the time of starting, the HC emission amount can be reduced. Furthermore, by performing afterburning by two (split) injections when the engine is cold, such as immediately after the engine is started, the three-way catalyst 115 can be warmed up (activated) early, and HC and NOx emissions during mode operation can be suppressed. Is possible. Further, by increasing the air utilization rate during the homogeneous combustion operation or by performing split injection in the intake stroke, it is possible to increase the maximum torque and obtain a high output.

  In the above-described embodiment, the fuel injection valves 10 and 10 ′ having six or four nozzle holes are used. However, the present invention is not limited to this, and the nozzle hole shape, the number of nozzle holes, the nozzle cross-sectional area, and The injection hole mode such as the direction of the injection hole can be changed as appropriate. Further, for example, even in the case of a single-hole swirl type fuel injection valve or a fuel injection valve having a slit-type injection port, a part of the injection port can be obtained by moving two or more overlapping orifice plates. Alternatively, various modes such as concealing the whole and changing the shape of the spray can be taken.

1 is a schematic side view showing an embodiment of an in-cylinder injection engine according to the present invention. 1 is a schematic plan view showing an embodiment of an in-cylinder injection engine according to the present invention. The longitudinal cross-sectional view which shows an example of the fuel injection valve used for the engine shown by FIG. 1, FIG. FIG. 4 is an enlarged cross-sectional view showing a lower end portion (portion peripheral portion) of the fuel injection valve shown in FIG. The figure which shows the 1st aspect of the nozzle hole of the outer orifice plate of the fuel injection valve shown by FIG. 3, FIG. The figure which shows the 1st aspect of the nozzle hole of the inner orifice plate of the fuel injection valve shown by FIG. 3, FIG. The figure which shows the mode of operation | movement at the time of the stratified combustion operation of the spray variable mechanism in the fuel injection valve shown by FIG. The figure which shows the mode of the action | operation at the time of the homogeneous combustion driving | operation of the spray variable mechanism in the fuel injection valve shown by FIG. The figure which shows the mode of a combustion chamber and its periphery when a piston exists in a compression stroke at the time of the stratified combustion operation of the engine shown by FIG. 1, FIG. The figure which shows the mode of a combustion chamber and its periphery when a piston exists in an intake stroke in the stratified combustion operation of the engine shown by FIG. 1, FIG. The figure which shows the 2nd aspect of the nozzle hole of the outer orifice plate of the fuel injection valve shown by FIG. 3, FIG. The figure which shows the 2nd aspect of the nozzle hole of the inner orifice plate of the fuel injection valve shown by FIG. 3, FIG. The figure which shows the 3rd aspect of the nozzle hole of the outer orifice plate of the fuel injection valve shown by FIG. 3, FIG. The figure which shows the 3rd aspect of the nozzle hole of the inner orifice plate of the fuel injection valve shown by FIG. 3, FIG. The figure which shows the 4th aspect of the nozzle hole of the outer orifice plate of the fuel injection valve shown by FIG. 3, FIG. The figure which shows the 4th aspect of the nozzle hole of the inner orifice plate of the fuel injection valve shown by FIG. 3, FIG. In the fuel injection valve of this invention and a prior art example, the figure which compares and shows the change of the amount of injection fuel at the time of changing a pulse width with the same fuel pressure. In the fuel injection valve of this invention and a prior art example, the figure which compares and shows the change of the fuel injection amount when it is set as the same pulse width. The longitudinal cross-sectional view which shows the other example of the fuel injection valve used for the engine shown by FIG. 1, FIG. FIG. 3 is a view showing an air-fuel mixture distribution in a combustion chamber when split injection is performed at the start in the engine shown in FIGS. 1 and 2. The figure which shows the state of the air-fuel | gaseous mixture in a combustion chamber at the time of carrying out divided injection at the time of high load in the engine shown by FIG. The figure which shows the effect of this invention embodiment compared with a prior art example (comparison of the air fuel ratio in a stratified operation, fuel consumption, HC and NOx discharge | emission amount, and the output in a homogeneous time).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer orifice plate 1a ... Stratification nozzle 1b ... Homogeneous nozzle 1c ... Weak stratification nozzle 2 ... Inner orifice plate 2a ... Stratification nozzle 2b ... Homogenization nozzle 2c ... Weak stratification nozzle 3 ... Outer holder 4 ... Inner holder 6 ... movable vane 7 ... fixed vane 8 ... plunger 10 ... fuel injection valve 11 ... spring 12 ... core 13 ... resin mold 14 ... yoke 15 ... coil 16 ... housing 20 ... electrode 21 ... spring 22 ... gap 40 ... stepping motor coil 41 ... Stepping motor shaft 90 ... Cylinder injection engine 92 ... Cylinder 95 ... Combustion chamber 101 ... Intake passage 102 ... Partition plate 103 ... Intake control valve 104 ... Throttle sensor 105 ... Air flow sensor 106 ... Air cleaner 107 ... Piston 108 ... Electronic throttle Valve 110 ... Drain Air passage 111 ... Intake valve 112 ... Exhaust valve 113 ... Spark plug 115 ... Three-way catalyst 116 ... Collector 117 ... Silencer 120 ... Tumble 125 ... Spray 200 ... Control unit O ... Center axis F ... Fuel

Claims (15)

  A plurality of nozzle holes that can be overlapped with each other have two orifice plates formed in a predetermined arrangement state, and by rotating or moving one plate with respect to the other plate, the nozzle hole shape and opening A fuel injection valve characterized in that it can change at least one of the number of injection holes, the cross-sectional area of the injection holes, and the direction of the injection holes.   2. The fuel injection valve according to claim 1, further comprising a vane mechanism that rotates one plate with respect to the other plate by using a pressure of the fluid.   The fuel injection valve according to claim 2, wherein the vane mechanism rotates one plate with respect to the other plate using a pressure of fuel supplied into the valve.   The fuel injection valve according to claim 1, further comprising a stepping motor for rotating one plate with respect to the other plate.   5. The fuel injection valve according to claim 2, wherein the vane mechanism or the stepping motor is disposed between a valve drive coil and the plate.   The fuel injection valve according to any one of claims 1 to 5, wherein an arrangement mode of the nozzle holes of one orifice plate is different from an arrangement mode of the nozzle holes of the other orifice plate.   7. The fuel injection valve according to claim 1, wherein the cross-sectional area or the diameter of the nozzle hole of one orifice plate is larger than the cross-sectional area or the diameter of the nozzle hole of the other orifice plate. .   8. The at least one of the two orifice plates of the two orifice plates has an elongated hole shape formed of an arc having an equal distance from the center. Fuel injection valve.   The two orifice plates have conical surfaces that slidably contact each other, and the nozzle holes are opened in the conical surfaces. The fuel injection valve as described.   The fuel injection valve according to any one of claims 1 to 9, wherein the injection hole is inclined outward with respect to a central axis. The fuel injection valve according to any one of claims 1 to 10, an air-fuel mixture generation adjustment mechanism for stratifying an air-fuel mixture, generating a homogeneous air-fuel mixture, and the like, the fuel injection valve, and the air-fuel mixture generation Control means for controlling the adjustment mechanism,
The control means changes at least one of the shape of the nozzle hole, the number of nozzle holes to be opened, the nozzle hole cross-sectional area, and the direction of the nozzle hole, based on the operating state, and the shape of the fuel spray, the injection rate, etc. An in-cylinder injection engine that is controlled to change its characteristics.   The in-cylinder injection engine according to claim 11, wherein the fuel injection valve is provided sideways on the intake passage side in the combustion chamber.   The air-fuel mixture generation adjustment mechanism is arranged at a partition plate that divides the downstream passage portion of the intake passage into an upper passage portion and a lower passage portion, and is disposed at an upstream end portion of the lower passage portion, and the lower passage An in-cylinder injection engine according to claim 11 or 12, further comprising an intake control valve that selectively opens and closes the section.   The fuel injection valve is provided with the vane mechanism for rotating one plate with respect to the other plate using the pressure of the supplied fuel, and the control means increases the fuel pressure during the stratified combustion operation. The characteristics of the fuel spray shape, injection rate, etc. are changed by lowering or increasing the fuel pressure during the homogeneous combustion operation, or by increasing or decreasing the fuel pressure. An in-cylinder injection engine according to claim 1.   The in-cylinder injection engine according to any one of claims 11 to 14, wherein the control unit performs control such that fuel injection is performed in a plurality of times for each combustion cycle.

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