JPH0735761B2 - Acceleration device for accumulator injection type diesel engine - Google Patents

Description

Description: <Industrial application> The present invention relates to a lead angle device for a pressure-accumulation injection type diesel engine, and in particular, the structure of the lead angle device can be simplified and the reliability can be improved. The present invention relates to a lead angle device for a pressure-accumulation injection type diesel engine in which a lead angle device is built in a fuel supply system to enhance versatility.

<Premise Structure> The advancing device of the pressure-accumulation injection diesel engine of the present invention is, for example, FIG. 1 (present invention) or FIG. 15 (prior art).
As shown in, the target is one having the following prerequisite structure.

That is, the fuel tank 1 is replaced by the pressure adjusting device 12, the metering device 14,
The pressure regulating device 12 is communicatively connected to the pressure accumulation type fuel injector 29 through the supply timing determination valve 18 and the fuel injection pump 26, and the pressure regulator 12 is configured to increase the fuel supply pressure in accordance with the engine speed. The supply timing determination valve 18 allows the fuel metered by the metering device 14 to be supplied to the fuel injection pump 26 when the valve is opened, while the fuel is discharged from the fuel injection pump 26 when the valve is closed. It is configured to prevent the fuel to be flowed back to the metering device 14. Where the accumulator fuel injector 29
And, as illustrated in FIG. 11, after the fuel is injected into the injected fuel pressure accumulating chamber 86 through the valve closing pressurizing chamber 85 and the check valve 95,
When the internal pressure of the valve closing pressurizing fuel chamber 85 is reduced and the internal pressure of the valve closing pressurizing fuel chamber 85 in the injector 29 falls below a predetermined value, the internal pressure of the injected fuel pressure accumulating chamber 86 becomes the valve closing biasing force of the valve closing spring 91. Also, the injection valve 88 is opened by overcoming the internal pressure of the valve closing pressurizing fuel chamber 85, and the fuel in the injected fuel pressure accumulating chamber 86 is injected from the injection hole 87. The depressurization of the valve closing pressurization fuel chamber 85 is communicated with the pump chamber 82 of the fuel injection pump 26.

<Prior Art> Conventionally, in the valve closing pressurizing fuel chamber 85, the check valve 95 is opened from the pump chamber 82 to inject fuel into the injected fuel pressure accumulating chamber 86, and then the plunger 81 of the fuel injection pump 26 is raised. The pressure is reduced. Drive device 5 for driving this plunger 81
As shown in FIG. 14, includes a fuel injection cam 30, a cam follower 31, a push rod 32, and a rocker arm 33 which are interlocked with a crankshaft C (shown in FIG. 2). The advancement device that changes the operation timing of the fuel injection pump 26 according to the engine rotation speed is pivotally supported by the meat wall portion 105 of the engine so as to be swingable, and the rotation phase is changed according to the rotation speed of the engine. The eccentric shaft 106 is provided. A swing arm-shaped cam follower 31 is pivotally supported on the eccentric shaft 106.

With this advance device, when the engine speed increases,
The eccentric shaft 106 swings to the advance side, the cam follower 31 moves to the advance side (toward the rotational direction of the fuel injection cam 30), and the timing at which the fuel pump 26 is driven by the fuel injection cam 30 is advanced. Eccentric shaft when engine speed decreases
106 and the cam follower 31 move in the opposite direction, and the operation timing of the fuel injection pump 26 is delayed.

<Problems to be Solved by the Invention> In the conventional advancing device for the pressure-accumulation injection diesel engine as described above, the locus of movement of the fulcrum of the cam follower 31 draws a sine wave, with respect to the rotational speed of the engine. It is difficult to make the advance angles proportional to each other. Further, with respect to the rotation speed of the engine, an attempt is made to control the change of the rotation phase of the eccentric shaft 106 so that the fulcrum of the cam follower 31 moves in the tangential direction of the cam base circle of the fuel injection cam in proportion to the rotation speed of the engine, for example. Then, it becomes necessary to provide a complicated correction device. Further, for example, it is difficult to give a special torque characteristic to the engine by giving some change to the advance angle characteristic.

Further, since the locations of the fuel injection cam 30 and the fuel injection pump 26 are different depending on the model of the engine, it is necessary to make the shapes and sizes of the parts different for each model, which is also a problem of poor versatility.

The present invention has been made in view of the above circumstances,
Provided is an accumulator injection type diesel engine advancing device which can simplify the structure of the advancing device and further improve reliability, and which has an advancing device built into the fuel supply system to enhance versatility. The purpose is to do.

<Means for Solving Problems> An advancement device for a pressure-accumulation injection diesel engine according to the present invention is an advancement device for a pressure-accumulation injection diesel engine having the above-described prerequisite structure, and achieves the above object. To this end, the following technical measures are taken, for example, as shown in FIGS. 1 to 11.

That is, the injection timing setting pressure relief valve 19 and the injection timing adjustment advance valve 20 are sequentially connected to the valve closing pressurization fuel chamber 85 of the fuel injector 29, and the pressure relief valve 19 is formed in the valve box 56. A plurality of pressure relief valve body passages 59 formed in the pressure relief valve body 57 are configured to communicate intermittently with the rotation of the pressure relief valve body 57 in the passage 24. Is communicated with the valve closing pressurizing fuel chamber 85, the depressurizing valve element 57 is timed and interlocked with the crankshaft C of the diesel engine, and the advance valve 20 is formed on the advance valve element 61. The angle valve body passage 62 is configured to selectively communicate with each of the plurality of pressure release valve body passages 59 according to the sliding displacement of the advance angle valve body 61, and The respective pressure relief valve body passages 59 are formed in the pressure relief valve body 57 so as to be offset from each other in the rotational direction and the axial center direction thereof, and are formed along the axial center direction in the pressure relief valve body 57. Advance Forming a valve chamber 60, the advance valve body to the advanced angle valve chamber 60
61 is slidably inserted, and the advance valve body passage 62 is formed on the outer peripheral surface of the advance valve body 61 by running in the circumferential direction. It is configured such that the valve 65 is biased to slide to the retard side and is biased to the advance side by the fuel pressure of the advance pressure receiving chamber 63. It is characterized by being configured to communicate with 12.

<Operation of the Invention> In the above-described configuration, the introduction passage 24 has the injection timing setting pressure relief valve.
When at least one depressurizing valve body passage 59 of 19 and the communicating depressurizing valve body passage 59 and advancing valve body passage 62 communicate with each other, Depressurization of the valve closing fuel chamber 85 is started.

Since the timing at which the pressure relief valve body passage 59 and the introduction passage 24 communicate with each other is adjusted with respect to the crankshaft C, the timing of the decompression start of the valve closing pressurization fuel chamber 85 is eventually the advance valve body passage 62. Is adjusted depending on which pressure release valve body passage 59 is communicated with.

That is, the advance angle can be adjusted simply by slidingly advancing the advance angle valve body 61, and the advance angle device can be simplified. Further, in this way, the advancement device is not attached to the drive device 5 of the fuel injection pump 26, but is provided in the middle of the fuel supply system, so that there is no problem of dimensional difference depending on the model of the engine, and many types The same advancing device can be applied to the engine, increasing versatility.

Further, the advancement device is composed of two parts, the valve box 56 and the advancement valve body 61 which is slidably displaced in the valve case 56, and the structure is simple and the failure is unlikely to occur, and the reliability can be improved. .

<Examples> Examples of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the fuel system of this diesel engine measures the fuel in the fuel tank 1 by the metering and supplying device 2 in accordance with the load condition of the engine, and supplies the timing control composite valve device 3 with the timing. The fuel is supplied to the unit injector 4 at a predetermined timing via the decision valve 18, and the fuel injection pump
26 is driven by the drive unit 5 to accumulate pressure
After press-fitting into 29, the injection timing setting depressurizing valve 19 and the injection timing adjusting advance valve 20 of the timing control combined valve device 3 depressurize the fuel in the valve closing pressurizing fuel chamber 85 of the pressure accumulating fuel injector 29. The fuel is released into the breathing chamber 21 to reduce the internal pressure of the fuel chamber 85 for pressurizing the valve, and thereby the injection valve 88 is opened to inject the fuel pressure accumulation chamber 86.
Fuel is injected from the injection hole 87 through the injection hole 87, and the fuel in the depressurized fuel breathing chamber 21 is discharged back to the unit injector 4 through the depressurized fuel return passage 22 at a predetermined timing after the end of the injection to be depressurized. The reduced fuel is returned to the unit injector 4, and then the initial pressure supply passage 23 of the timing control combined valve device 3 is communicated with the unit injector 4 to return the unit injector 4 to the initial state.

As shown in FIG. 2, the metering and feeding device 2 is a transfer pump incorporated in a thick-walled cylindrical casing 6.
10, pressure regulator 12 (Fig. 4), metering device 14 and pressure pump
16, the fuel pump 1 pumps fuel from the fuel tank 1 through the fuel pipe (not shown), the inlet joint 8 (FIG. 4) and the inlet passage 9 (FIG. 4), and the fuel is discharged from the transfer pump 10. The pressure of the fuel is increased / decreased by the pressure adjusting device 12 according to the rotation speed of the engine (for example, in direct proportion), and the pressure-adjusted fuel is adjusted by the amount adjusting device 14 according to the load state of the engine, The pressure-controlled / metered fuel is pressure-fed by the pressure-feed pump 16 to the timing control combined valve device 3.

The transfer pump 10 has a pump chamber 34 formed at the front end portion of the casing 6, and in the pump chamber 34, as shown in FIG. 3, an inner rotor 35 fixed to the main shaft 7 penetrating the casing 6 and The eccentrically meshed outer rotor 36 is inserted into this, and the fuel is sucked from the inlet passage 9 through the suction port 37 into the space between the rotors 35 and 36, and then discharged from the discharge port 38 to the discharge passage 11 (Fig. 4). It is designed to discharge.

As shown in FIG. 4, the pressure adjusting device 12 is connected to the discharge passage 11 in a branched manner, and has a pressure adjusting plug 39 screwed to the casing 6,
A pressure regulating valve body 40 slidably fitted therein is provided, and a valve closing spring 41 for urging the pressure regulating valve body 40 to a valve closing position. A pressure regulating valve hole 42 is opened in the peripheral wall of the pressure regulating plug 39, and the pressure regulating valve hole 42 is communicated with the inlet passage 9. The discharge pressure of the transfer pump 10 corresponds to the engine speed 2
It changes in a quadratic function, and in response to this discharge pressure, the pressure regulating valve body 40 is urged against the valve closing spring 41 in the valve opening direction. This pressure regulator
In 12, by appropriately setting the opening area of the pressure regulating valve hole 42 with respect to the displacement amount of the pressure regulating valve body 40 from the closed position, the fuel escaped from the pressure regulating device 12 to the inlet passage 9 in correspondence with the rotation speed of the engine. By adjusting the amount, the internal pressure of the discharge passage 11 is accurately increased or decreased in direct proportion to the rotation speed of the engine. However, the correspondence relationship between the internal pressure of the discharge passage 11 controlled by the pressure regulator 12 and the rotation speed of the engine is not limited to the direct proportion, and for example, the increase rate of the internal pressure of the discharge passage 11 decreases as the speed increases. Alternatively, the increasing rate of the internal pressure of the discharge passage 11 may increase as the speed increases. A drain pipe joint 43 for connecting a drain pipe (not shown) for discharging fuel leaked from between the pressure regulating plug 39 and the pressure regulating valve body 40 is connected to the pressure regulating plug 39.

As shown in FIG. 2, the metering device 14 includes a metering piston 44 which is fitted in the front half of the main shaft 7 so as to be able to move forward and backward. The metering piston 44 is driven in the fuel reducing direction (here, forward) against the pressure of the governor spring 46 by the thrust of the flyweight 45 corresponding to the rotation speed of the engine. A metering valve hole 47 communicating with the discharge passage 11 is opened in the inner peripheral surface of the main shaft 7, and the metering piston hole 47 is opposed to the metering valve hole 47.
A metering valve body passage 48 is provided on the peripheral surface of the groove 44 along the entire circumference thereof. Then, as the metering piston 44 moves back and forth according to the engine speed, the connection area between the metering valve hole 47 and the metering valve body passage 48 is changed so as to correspond to the engine speed. The flow rate is adjusted and the spindle 7
Further, the fuel is guided to the pressure feed pump 16 through the outlet passage 49 formed in the casing 6. The pressure of the governor spring 46 can be changed and set by swinging the speed setting lever 50.

As shown in FIGS. 2 and 5, the pressure pump 16 has a swing arm formed by a drive cam 51 formed on the peripheral surface of the main shaft 7.
A plunger 53 driven via 52 and a pump chamber 54 whose volume changes as the plunger 53 moves forward and backward are provided. Further, the pressure pump 16 is configured to obtain pump characteristics corresponding to various torque characteristics suitable for engine applications by changing and setting the stroke of the plunger 53 by the torque characteristic setting device 55.

The timing control combined valve device 3 is incorporated in the casing 6 of the metering and feeding device 2 as shown in FIGS. 2 and 6 to 8 in order to achieve downsizing and compactness. The timing control combined valve device 3 essentially comprises a supply timing determination valve 18, an injection timing setting pressure relief valve 19, and an injection timing adjustment valve that can be provided independently as shown in FIG. The square valve 20 and the depressurized fuel breathing chamber 21 are integrally combined for downsizing and size reduction.

That is, as shown in FIG. 2 and FIGS. 6 to 8, the supply timing determination valve 18 that determines the timing at which the fuel is pressure-fed to each unit injector 4 and the injection timing setting depressurization valve 19 are the latter half of the casing 6. A common valve box 56 made up of parts and a common valve body 57 made up of the latter half of the main shaft 7 are provided. At the rear end portion of the inner peripheral surface of the casing 6, a pressure feeding passage 27 led out from the pressure feeding pump 16 of the metering supply device 2 is opened, and an introduction passage (a distribution passage, hereinafter referred to as an inlet / outlet passage) to each unit injector 4 is opened slightly forward thereof. Called passages) 24 are opened at equal intervals in the circumferential direction. A communication groove portion 58a of the valve timing passage 58 for supply timing determination is recessed in the portion of the main shaft 7 opposed to the pressure feeding passage 27 over the entire circumference, and a passage locus of the passage 24 from one position in the circumferential direction of the communication groove portion 58a. The supply timing determining groove portion 58b is continuously extended in the axial direction along the peripheral surface up to the outer peripheral surface portion of the main shaft 7 opposed to l. Then, the main shaft 7 rotates in conjunction with a crank shaft (not shown), and the supply timing determining groove portion 58b and the inlet / outlet passage 24 overlap with each other to communicate with each other, so that the supply timing determining groove portion 58b and the inlet / outlet passage 24 communicate with each other through the supply timing determining valve body passage 58. The pressure-controlled / metered fuel is press-fitted into the inlet / outlet passage 24. In addition, in the portion of the outer peripheral surface of the main shaft 7 facing the passage locus 1 of the passage 24,
The pressure release valve body passage 59 of the injection timing setting pressure release valve 19 which is communicated with the inlet / outlet passage 24 is opened at a predetermined timing after the supply timing determination groove 58b.

The latter half of the main shaft 7, which is the common valve body 57 of the supply timing determination valve 18 and the injection timing setting pressure relief valve 19, further serves as a valve box of the injection timing adjusting advance valve 20. That is, a cylindrical advancing valve chamber 60 is formed concentrically in the latter half of the main shaft 7, and an advancing valve body 61 advances and retreats in the axial direction of the main shaft 7 in the advancing valve chamber 60. It is stored as much as possible. In the valve body 57, three pressure relief valve body passages 59 whose opening positions on the inner peripheral surface are different from each other in the rotation direction and the axial direction of the main shaft 7 are formed so as to penetrate the peripheral wall thereof, and are used for advancing. An advancing valve body passage 62 is formed on the circumferential surface of the valve body 61 so as to communicate with one of the three depressurizing valve body passages 59 or two adjacent ones. The advance valve body passage 62 is formed of a circumferential groove that is recessed over the entire circumference of the advance valve body 61. The advance valve chamber 60 has the advance valve body 61.
It is divided into an advance angle pressure receiving chamber 63 and a retard angle biasing chamber 64. Then, the advancing pressure receiving chamber 63 is communicated with the discharge passage 11 whose pressure is regulated by the pressure regulating device 12, the retard urging chamber 64 is communicated with the inlet passage 9 which is kept at a substantially constant pressure, and Chamber 64
A retard urging means 65 for urging the advance valve body 61 in the retard direction is housed inside, and the position of the advance valve body 61 is set to the engine rotation speed of the pressure adjusting device 12 as described later. It is configured so that it can be easily controlled with high accuracy depending on the pressure regulation characteristics for.

Here, the advance valve element 61 is moved in the axial direction and selectively communicates with the depressurizing valve element passage 59, but the advance valve element 61 corresponds to the rotational speed of the engine. The valve body 61 may be configured to rotate about the axis and selectively communicate with the pressure relief valve body passage 59.

The depressurized fuel breathing chamber 21 is formed inside the advance valve body 61 for downsizing and compactification. That is, a stepped cylindrical cavity 66 is formed inside the advance valve body 61.
66 is divided into a pressure-release fuel breathing chamber 21 and a discharge return urging chamber 68 by a piston 67 slidably fitted inside thereof. The discharge return urging chamber 68 communicates with the inlet passage 9 via the retard angle urging chamber 64, and stores the discharge return urging means 69 therein. The depressurized fuel breathing chamber 21 is connected to the advance valve body passage 62 by the breathing passage 70. First, the fuel injection pump
When the plunger 81 of 26 is driven to be discharged by the fuel injection cam of the drive device 5, the fuel in the pump chamber 82 is pressurized, and passes through the valve closing pressurizing fuel chamber 85 and the check valve 95, and then the injected fuel pressure accumulating chamber. Pressed into 86.

Then, the plunger 81 is held at the discharge end position by the fuel injection cam for a certain period of time (between time points fm in FIG. 13). In this state, the check valve 95 is closed, but the valve closing pressurizing fuel chamber 85 / pump is closed. The chamber 82 and the passage 24 are maintained at a high pressure.

In this high pressure holding state, when the inlet / outlet passage 24 communicates with the depressurized fuel breathing chamber 21 through the pressure relief valve body passage 59, the advance valve body passage 62 and the breathing passage 70, the high pressure fuel on the inlet / outlet passage 24 side is communicated. The pressure causes the piston 67 to be pushed into the discharge return urging chamber 68 side, and the fuel is pressed into the depressurized fuel breathing chamber 21. As a result, the internal pressure of the valve closing pressurizing fuel chamber 85 of the pressure accumulating fuel injector 29 communicating with the inlet / outlet passage 24 is reduced, and the injection valve 88 is opened to inject fuel. At this time, the pressure in the depressurized combustion breathing chamber 21 rises by the amount of the injected fuel.

A pressure release fuel return passage 22 communicating with the inlet / outlet passage 24 is formed at a predetermined timing after the pressure release valve body passage 59 at a portion of the peripheral wall of the main shaft 7 facing the passage locus 1 of the inlet / outlet passage 24. There is. First, after the fuel injection is completed, when the plunger 81 of the fuel injection pump 26 is actuated to the suction side, the internal pressure of the pump chamber 82 is reduced and the inlet / outlet passage 24 is also reduced in pressure.

Next, in the low pressure state of the pump chamber 82 and the inlet / outlet passage 24, the pressure-removed fuel breathing chamber 21 whose pressure has been increased is passed through the breathing passage 70, the advance valve body passage 62, and the pressure-release fuel return passage 22. By being communicated with the inlet / outlet passage 24, the discharge return urging means 69 pushes the piston 67 back to the pressure-release fuel breathing chamber 21 side, and the fuel press-fitted into the pressure-release fuel breathing chamber 21 flows through the inlet / outlet passage 24 in the low pressure state. After that, it is discharged back to the unit injector 4.

Further, an initial pressure supply passage 23, which communicates with the inlet / outlet passage 24 at a predetermined timing after the depressurized fuel return passage 22, is provided in the peripheral wall portion of the main shaft 7 facing the passage locus 1 of the inlet / outlet passage 24. There is. The initial pressure supply passage 23 communicates with the discharge passage 11 whose pressure is regulated by the pressure regulating device 12.

As shown in FIGS. 1 and 11, the unit injector 4 includes a compound shutoff valve 25 connected to the inlet / outlet passage 24, a fuel injection pump 26, a pump return pressure accumulator chamber 27, and a shutoff valve return accumulator chamber 28. And a pressure-accumulation type fuel injector 29, the fuel injection pump 26 is built in the body 83 of the injector 29, and the composite cutoff valve 25
Is further built into the plunger 81 of the fuel injection pump 26.

That is, the fuel injection pump 26 has the injection pipe 84 on one side of the body 83.
Plunger 81 fitted in parallel to and vertically movable
And a pump chamber 82 partitioned by a body 83 and a plunger 81. The plunger 81 is shaped like a hollow cylinder whose both ends are closed, and its internal space has a valve chamber 71 of the composite shutoff valve 25.
Are configured. A spool 72 is slidably inserted in the valve chamber 71, and the spool 72 causes the valve chamber 71 to
Accumulation chamber for pump return 27 on the bottom dead center side of the moving stroke of 72
And the shut-off valve return biasing chamber 73 on the top dead center side. The shut-off valve return bias chamber 73 is a shut-off valve return accumulator chamber 28.
Is in communication with. An inner entrance / exit passage 74 communicating with the entrance / exit passage 24 is opened at an intermediate height portion of the peripheral wall of the plunger 81, a pump communicating passage 75 communicating with the pump chamber 82 is opened at a lower portion thereof, and a shutoff valve recovery passage is provided at an upper portion thereof. A pressure accumulation communication passage 76 communicating with the dynamic pressure accumulation chamber 28 and the shutoff valve return urging chamber 73 is opened. The spool 72 is formed with a hollow hole 77 extending upward from the lower end surface thereof, and the peripheral wall of the spool 72 is a communication hole extending from the intermediate height thereof to the peripheral surface and constantly communicating with the internal inlet / outlet passage 74.
78, a pump valve hole 79 extending from its lower portion to the peripheral surface and communicating with the pump communication passage 75 when the spool 72 is located below the top dead center, and extending from the upper end portion to the peripheral surface, Accumulation passage when spool 72 is located at top dead center and bottom dead center
An accumulator valve hole 80 communicating with 76 is formed.

The pressure-accumulation fuel injector 29 includes an injection pipe 84 that is fitted into the other side of the body 83, and a valve closing pressurizing fuel chamber 85 and a first pressure accumulation chamber 96 are vertically arranged in the lower half of the injection pipe 84. Injection pipe formed in series
One or more (two in this case) injection holes 87 are formed at the lower end of 84. The injection valve 88 that closes the connection between the first pressure accumulating chamber 96 and the injection hole 87 in the vicinity of the injection hole 87 is a needle valve, and the upper end of the valve shaft 89 is formed in the upper half of the injection pipe 84. The valve closing spring chamber 90 is made to plunge. Valve closing spring chamber 90
A valve-closing spring 91 for urging the injection valve 88 to be closed is housed in the valve. An adjusting nut 92 for adjusting the urging force of the valve-closing spring 91 is screwed to the upper end of the injection pipe 84 in an oil-tight manner. Covered by cover nut 93. The inner space 94 of the cover nut 93 is a valve closing spring chamber.
It communicates with 90, and together with this, constitutes a pressure accumulation chamber 28 for shut-off valve return. The valve closing pressurization fuel chamber 85 and the first pressure accumulation chamber 96 are partitioned by a check valve 95. The check valve 95 includes a valve seat 100 formed by enlarging a part of a valve shaft 89, an annular valve body 101 that contacts and separates from a lower surface of the valve seat 100, and a valve closing spring 102 that urges the valve to close.
Consists of. Around the middle height of the injection pipe 84, an annular second pressure accumulation chamber 97 partitioned by this and the body 83 is provided. This second pressure accumulation chamber 97 is located on the opposite side of the fuel injection pump 26. The second pressure accumulation chamber check valve 98 and the second pressure accumulation chamber pressure accumulation setting valve 99 arranged inside the body 83 are connected to the first pressure accumulation chamber 96, and together with the first pressure accumulation chamber 96 form the injected fuel pressure accumulation chamber 86. ing. The first pressure accumulating chamber 96 has a relatively small volume,
The second pressure accumulation chamber 97 has a relatively large volume.

The discharge passage 11 can be shut off by a solenoid valve 13 for emergency stop immediately before the metering device 14, and the outlet passage 49 can be shut off by a manual stop valve 15.

Next, the operation of this fuel system will be described.

As shown in Fig. 12 (1), in the initial state, the plunger
81 is located at the top dead center, and the spool 72 is located at the bottom dead center. Further, the internal pressures of the shutoff valve return pressure accumulation chamber 28, the pump return pressure accumulation chamber 27, the shutoff valve return biasing chamber 73, and the pump chamber 82 are reference pressures adjusted by the pressure adjusting device 12. Here, time point a in FIGS. 13 (1) to 13 (6) [hereinafter, simply referred to as time point a]. 13 (1) to 13 (6) is the same as the above), the supply timing determining groove portion 58b of the supply timing determining valve 18 and the inlet / outlet passage 24 are communicated with each other from time b to time b. The pressurized fuel Vin is press-fitted into the unit injector 4. First, this fuel Vin is shown in Fig. 12 (2).
As shown in FIG. 7, the spool 72 is pressed into the pump return pressure accumulating chamber 27, and the spool 72 is pushed up from the bottom dead center to the intermediate height. When the plunger 81 is lowered by the drive device 5 from the time point c after this, the internal pressures of the pump chamber 82, the pump return pressure accumulation chamber 27, the shutoff valve return biasing chamber 73, and the shutoff valve return pressure accumulation chamber 28 gradually increase. Ascend, and as shown in FIG. 12 (3), the pump chamber 82
When the amount of fuel equal to the maximum injection amount Vmax is injected from the pump recuperation pressure accumulating chamber 27 to the pump recuperation chamber 27, that is, the amount of fuel pushed out from the pump chamber 82 in the remaining stroke of the plunger 81 becomes equal to the injected fuel Vin. Then, the spool 72 is raised to the top dead center. Since the check valve 95 of the fuel injector 29 is closed during the downward stroke of the plunger 81 from the time point c to the time point d when the spool 72 reaches the top dead center, the fuel is not injected into the fuel injector 29. Called invalid stroke. When the spool 72 reaches the top dead center, the internal pressure of the pump chamber 82 reaches the valve opening pressure of the check valve 95 and the pump communication passage 75.
And the pump valve hole 79 are shut off. Further, the pressure accumulation valve hole 80 is communicated with the pressure accumulation communication passage 76, and the internal pressure of the pump return pressure accumulation chamber 27 is corrected so as to match the internal pressures of the shutoff valve return accumulation chamber 28 and the shutoff valve return biasing chamber 73. . After this time point d, the fuel Vin is injected into the injected fuel pressure accumulating chamber 86 as the plunger 81 descends and the internal pressure of the pump chamber 82 further increases. The fuel injected into the injected fuel pressure accumulating chamber 86 is exclusively pressed into the first pressure accumulating chamber 96 until the pressure e reaches the internal pressure of the second pressure accumulating chamber 97, and the pressure exceeds the internal pressure of the second pressure accumulating chamber 97. When the second accumulator check valve 98 is opened and the plunger 81 reaches the bottom dead center as shown in FIG. 12 (4), the fuel pressure stops increasing and the check valve 95 is opened. The valve is closed and the fuel Vin is accumulated in the injected fuel pressure accumulator 86 at high pressure. Then, at a predetermined time point g thereafter, the entrance / exit passage 24 is communicated with the depressurization fuel breathing chamber 21 through the pressure relief valve body passage 59, the advance valve body passage 62 and the breathing passage 70, and the entrance / exit passage 24 The internal pressure of starts to be reduced. The timing of this decompression start is based on the advance valve body passage.
Since the pressure relief valve body passage 59 communicating with 62 communicates with the inlet / outlet passage 24, it is set faster than the standard timing when the engine rotation speed is high, and the engine rotation speed is increased. If it is late, it will be later than the standard timing.

Here, as the engine speed increases, the internal pressure of the advance pressure receiving chamber 63 increases in direct proportion to the engine speed, the advance valve body 61 moves in the advance direction, and the main shaft 7 rotates on the best hand side. The pressure relief valve body passage 59 and the advance valve body passage 62 communicate with each other, so that the central pressure relief valve body passage 59 and the advance valve body passage
The entrance / exit passage 24 is communicated with the advance valve body passage 62 through the pressure-release valve body passage 59 earlier than the case where 62 is communicated, so that the injection timing is advanced. Further, when the engine speed decreases, the pressure relief valve body passage 59 on the rotation lower side of the main shaft 7 and the advance valve body passage 62 communicate with each other, thereby advancing to the center pressure relief valve body passage 59. The inlet / outlet passage 24 is communicated with the advance valve body passage 62 via the pressure release valve body passage 59 later than the case where the angle valve passage 62 is communicated, and the injection timing is delayed. At an intermediate speed, the central pressure relief valve body passage 59 and the advance valve body passage 62 communicate with each other, and the passageway enters and leaves at standard timing.
24 is connected to the advance valve body passage 62 through the pressure relief valve body passage 59, and the pressure relief for injection is performed at standard timing. The advance valve body passage 62 not only selectively communicates with each pressure relief valve body passage 59, but also in the excessive region of the rotational speed region corresponding thereto, the center and uppermost pressure relief valve body passages. 59 or two pressure release valve body passages 59 in the center and the lowermost pressure release valve body passage 59 can be communicated at the same time. Depending on the ratio of the connection area with both pressure release valve body passages 59, the rise characteristics of the pressure release Is changing. In this manner, the position of the advance valve body 61 can be easily and highly accurately controlled depending on the pressure adjusting characteristic of the pressure adjusting device 12 with respect to the engine rotation speed, so that the advance angle can be easily and accurately controlled. become.

When the pressure release starts, the spool 72 descends from the top dead center,
From the time h when the communication between the pump valve hole 79 and the pump communication passage 75 is restored, the internal pressure of the valve closing pressurizing fuel chamber 85 suddenly decreases, and the internal pressure of the valve closing pressurizing fuel chamber 85 drops to a predetermined valve opening pressure. From the time i, the differential pressure acting on the check valve 95 overcomes the biasing force of the valve closing spring 91 and the injection valve 88 is opened.

As described above, when the spool 72 reaches the top dead center, the pressure accumulation valve hole 80 and the pressure accumulation communication passage 76 communicate with each other, so that the injector 29
When the fuel is injected into the
The rise in the internal pressure of the pump return pressure accumulator chamber 27 caused by the leak fuel to the pump is corrected, and the timing at which the pump communication passage 75 and the pump valve hole 79 communicate with each other at the time of depressurization is prevented from being delayed. Then, the occurrence of an injection timing error (delay) due to this communication delay is prevented.

Here, the pump communication passage 75 is composed of a small-diameter pump communication passage 75a and a large-diameter pump communication passage 75b which are vertically arranged, and the spool 72
Starts to descend from the top dead center and the small-diameter pump communication passage 75a communicates with the pump valve hole 79 first, so that the decrease in the internal pressure of the valve closing pressurization fuel chamber 85 is suppressed relatively slowly, and the valve opening amount of the injection valve 88 is reduced. Is suppressed to a small amount and the amount of fuel injection is suppressed to a small amount, and the reduction of the internal pressure of the injected fuel pressure accumulating chamber 86 due to the fuel injection is suppressed to be small. Then, when the spool 72 further descends and reaches, for example, a time point j corresponding to the ignition time point at the rated rotation speed, the large diameter pump communication passage 75b communicates with the pump valve hole 79, and the valve closing pressurization fuel chamber is suddenly opened. The internal pressure of 85 is reduced, the injection valve 88 is suddenly and largely opened, and a large amount of fuel is vigorously injected at high pressure. In this way, by suppressing the fuel injection amount before ignition to a small amount, it is possible to reduce the explosion sound at the time of ignition and prevent operating noise. Further, by injecting a large amount of fuel at a high pressure after ignition, it is possible to obtain the maximum thermal efficiency as long as it is allowed to reduce the operating noise. Further, since the injection pressure is a high pressure inside the injected fuel pressure accumulating chamber 86, it is possible to inject a predetermined amount of fuel Vin in a short time. Then, after the time point k when the internal pressure of the injected fuel pressure accumulating chamber 86 becomes equal to or lower than the setting pressure of the pressure accumulating setting valve 99 for the second pressure accumulating chamber, the pressure accumulating setting valve 99 is closed and the internal pressure of the second pressure accumulating chamber 97 is set to that value. Hold on to pressure. On the other hand, the volume of the injected fuel pressure accumulating chamber 86 communicating with the injection hole 87 is substantially reduced to that of the first pressure accumulating chamber 96, and even if a small amount of fuel is injected, the internal pressure of the first pressure accumulating chamber 96 is reduced. Then, the internal pressure is reduced to a predetermined valve closing pressure in a short time, and the injection valve 88 is closed (time l). Therefore, the injection time can be greatly shortened, which is advantageous in increasing the engine speed. At a predetermined time point m after the fuel injection ends, the fuel injection cam of the drive device 5
The cam lift of 30 starts to decrease, and the plunger 81 rises while being pressed against the rocker arm 33 of the drive device 5 by the internal pressure of the pump chamber 82. As the plunger 81 rises, the volume of the pump chamber 82 increases and the internal pressures of the pump chamber 82 and the pump return pressure accumulator chamber 27 are reduced.
The spool 72 is lowered by the pressure of 73 and the fuel is pushed from the pump return pressure accumulation chamber 27 into the pump chamber 82 until the amount of fuel equal to the maximum injection amount Vmax is injected from the pump return pressure accumulation chamber 27 into the pump chamber 82. To be

By the way, during the depressurization period after the time point g, fuel escapes from the pump return pressure accumulating chamber 27 to the depressurized fuel breathing chamber 21 side. Therefore, if the spool 72 is lowered to the bottom dead center as it is, the timing control composite is performed. The amount of fuel filled from the valve device 3 to the unit injector 4 side becomes smaller than in the initial state, and when the pressure-adjusted / metered fuel is next pressed into the unit injector 4, the spool 72 corresponds to the press-fitted amount. As a result, only a position lower than the height to be raised rises, which causes a problem that the fuel injection amount becomes insufficient.

Therefore, at time n when the spool 72 descends to the vicinity of the bottom dead center, the pressure-release fuel breathing chamber 21 has the breathing passage 70 and the pressure-release fuel returning passage.
The fuel that has been communicated with the inlet / outlet passageway 24 via 22 and has been pushed into the depressurized fuel breathing chamber 21 for depressurization is discharged back into the inlet / outlet passage 24 by the discharge return urging means 69, and further the pump return pressure accumulation pressure It is discharged back into the chamber 27 and the pump chamber 82. By discharging the fuel thus sucked back to the unit injector 4, a fuel shortage at the next injection is prevented. However, since the fuel contained in the depressurized fuel breathing chamber 21 is higher than the initial pressure, the internal pressure of the pump return pressure accumulating chamber 27 and the pump chamber 82 becomes higher than the initial state, and the spool 72 is lowered. It is moved to the top dead center side from the vicinity of the dead center. Therefore, in order to return from this state to the initial state, the initial pressure supply passage 23 is finally communicated with the inlet / outlet passage 24 at the predetermined time point o, and the shut-off valve return pressure accumulation chamber 28,
The internal pressures of the pump return pressure accumulation chamber 27, the shutoff valve return biasing chamber 73, and the pump chamber 82 are returned to the reference pressure adjusted by the pressure adjusting device 12, and the spool 72 is returned to the bottom dead center.

By the way, the internal pressures of the shut-off valve return accumulator chamber 28 and the shut-off valve return energizing chamber 73 are increased due to fuel leakage from the second accumulator chamber 97, or due to leaks to the pump return accumulator chamber 27 during depressurization. It may be decompressed. If the internal pressures of the shutoff valve return pressure accumulating chamber 28 and the shutoff valve return biasing chamber 73 increase, the spool is driven by the internal pressure of the shutoff valve returning pressure accumulating chamber 28 when fuel is injected from the metering supply device 2 next time. The rise of 72 is hindered, and the pressure accumulation volume of the pump return pressure accumulation chamber 27 is narrowed. As a result, after the fuel is press-fitted into the injector 29, when the plunger 81 rises, the pump return pressure accumulating chamber 27 to the pump chamber 82
Since the amount of fuel injected into the cylinder is insufficient, the plunger 81 cannot rise to the top dead center, resulting in operating noise. Further, if the internal pressures of the shutoff valve return accumulator chamber 28 and the shutoff valve return biasing chamber 73 are reduced, fuel is injected from the metering supply device 2 next time, and when the plunger 81 is lowered, the pump communication passage 75 and The timing at which the pump valve hole 79 is shut off is delayed, and the fuel injection amount is reduced.

Here, when the spool 72 is returned to the bottom dead center,
80 again communicates with the pressure accumulation communication passage 76, and the pressure accumulation chamber 28 for shut-off valve return movement
Since the internal pressure of the shut-off valve return urging chamber 73 is corrected to the reference pressure (initial pressure), the generation of operating noise due to the increase of these internal pressures and the occurrence of the injection amount error (decrease) due to the pressure reduction are prevented. It will be done.

<Effects of the Invention> As described above, according to the advancing device for the pressure-accumulation injection diesel engine according to the present invention, the position of the advancing valve element is dependent on the pressure adjusting characteristic with respect to the engine rotation speed of the pressure adjusting device. Since it can be easily controlled with high precision, it is possible to easily and accurately control the selection of a plurality of pressure relief valve disc passages that are displaced in the sliding direction of the advance valve disc. By communicating with each other, the advance timing can be easily controlled with high accuracy. Therefore, it becomes easy to give a required torque characteristic to the engine.

Further, since the advancement device is not provided in the drive device outside the fuel supply passage of the fuel injection device but is incorporated in the fuel supply passage, the same advancement device can be used across many types of engines, and versatility is improved. To be enhanced.

Furthermore, the mechanism of the advance valve is simple, and malfunction does not easily occur,
Effects such as high reliability can also be obtained.

[Brief description of drawings]

FIG. 1 is an equivalent circuit diagram showing an overall configuration of a lead angle device for a pressure-accumulation injection type diesel engine according to an embodiment of the present invention.
FIG. 4 is a vertical sectional side view of the fuel metering supply device, FIG. 3 is a vertical sectional front view of the transfer pump, FIG. 4 is a vertical sectional front view of the pressure regulating device, and FIG. 5 is a vertical sectional front view of the pressure pump. FIG. 6 is a vertical sectional side view of the timing control combined valve device. FIG. 7 is a vertical front view of the timing control combined valve device. FIG. 8 is a perspective view of the common valve body. Fig. 11 is a development view showing the arrangement of the valve passages, the depressurized fuel return passage and the initial pressure supply passage formed on the peripheral surface. Fig. 9 is a perspective view in which a part of the valve for adjusting the advance angle is cut away, Fig. 11 Is a vertical sectional view of the unit injector, and FIG. 12 (1) to 12
Fig. (4) is a schematic view showing the operation of the pump return pressure accumulating chamber in sequence, and Figs. 13 (1) to 13 (6) are operation timings, pressure changes and timing control of respective parts of the unit injector. Timing diagrams showing the relationship of the operation timing of the compound valve device, FIG. 14 is a configuration diagram of a conventional fuel injection pump drive device and advance device, and FIG. 15 is an entire pressure accumulation type fuel injection device of a conventional diesel engine It is an equivalent circuit diagram which shows a structure. DESCRIPTION OF SYMBOLS 1 ... Fuel tank, 12 ... Pressure adjusting device, 14 ... Metering device, 18 ... Supply timing determining valve, 19 ... Injection timing setting pressure relief valve, 20 ... Injection timing adjusting advance valve, 24 ... Introduction path, 26 ... Fuel injection pump, 29
… Accumulation type fuel injector, 56… Valve box, 57… Depressurizing valve element, 59…
Pressure relief valve body passage, 60 ... Advance valve chamber, 61 ... Advance valve body, 62
… Advance valve passage, 63… Advance pressure receiving chamber, 85… Close valve pressurizing fuel chamber, C… Crankshaft.

Claims (1)

[Claims] 1. A fuel tank (1) is provided with a pressure accumulator fuel injector () through a pressure regulator (12), a metering device (14), a supply timing determination valve (18) and a fuel injection pump (26). 29), the pressure regulator (12) is configured to increase the fuel supply pressure in accordance with the engine speed, and the supply timing determination valve (18) regulates when the valve is opened. While the fuel metered by the metering device (14) is allowed to be supplied to the fuel injection pump (26), the fuel discharged from the fuel injection pump (26) when the valve is closed is controlled by the metering device ( In the advance device of the pressure-accumulation injection type diesel engine configured to prevent the reverse flow to the injection valve (14), the injection timing setting pressure relief valve (19) is provided in the valve closing pressurization fuel chamber (85) of the fuel injector (29). ) And the advance valve for adjusting the injection timing (2
0) in order, and the pressure relief valve (19) is connected to the introduction passage (2) formed in the valve box (56).
4) A plurality of pressure relief valve body passageways (59) formed in the pressure relief valve body (57) are configured to intermittently communicate with each other as the pressure relief valve body (57) rotates. The introduction passage (24) communicates with the valve closing pressurization fuel chamber (85), and the depressurization valve body (57) is timedly interlocked with the crankshaft (C) of the diesel engine. In (20), the advance valve body passage (62) formed in the advance valve body (61) is different from the advance valve body passages (59) in the advancement valve body passages (59). The plurality of pressure release valve body passages (59) are connected to the pressure release valve body (57) in the direction of rotation thereof. They are formed so as to be offset from each other in the axial direction, and an advance valve chamber (60) is formed in the pressure relief valve body (57) along the axial direction of the valve body (57). ), And insert the advance valve body (61) into the The advance valve body passage (62) is formed on the outer peripheral surface of the advance valve body (61) by running in the circumferential direction, and the advance valve body (61) is formed by the retard urging means (65). Energized so as to slide to the retard side, and also the advance pressure receiving chamber (63)
Accumulation injection type diesel engine, characterized in that it is configured to be biased toward the advance side by the fuel pressure of, and the advance pressure receiving chamber (63) is connected to the pressure adjusting device (12). Advance device.