JPS5823960Y2 - Injection timing adjustment device for distributed fuel injection pump - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an injection timing adjustment device for a distributed fuel injection pump for an internal combustion engine.

Generally, in injection-type internal combustion engines such as diesel engines,
It is necessary to advance the injection timing as the rotational speed increases.

For this purpose, an injection timing adjustment device (timer) is used; in distributed fuel injection pumps, such a timer adjusts the internal pressure in the pump housing, which is supplied with fuel by an oil transfer pump driven in relation to engine rotation. It includes a responsive timer piston, and transmits displacement of the piston to an injection timing control member.

However, in this type of timer, the injection timing is uniquely determined by the number of rotations, and when the number of rotations is constant, it is not possible to control the injection timing in accordance with the load.

For this reason, if adjustment is made to match the full load (4/4 load), the injection timing will be too advanced compared to the optimal timing at partial loads, leading to deterioration of emissions and an increase in combustion noise (especially idle noise). If the injection timing is adjusted according to the partial load, the injection timing becomes too late at full load, resulting in insufficient output.

Therefore, as a main measure against emissions and idle noise, the internal pressure inside the pump housing that acts on the timer piston is corrected in relation to the engine load.
There is a load timer mechanism that delays the injection timing at partial loads (this will be explained in the example below), but the characteristics obtained by this mechanism are as shown in Figure 1, and even at 0/4 load. The mechanism was such that the injection timing could not be delayed below 0° advance angle at 4/4 load.

Therefore, in particular, the N1 to N2 rotation range shown in the figure falls within the emission mode range, so even though we would like to further delay the injection timing at partial load in this range to obtain the characteristics shown in Figure 2, we cannot do this. That was the reality.

In view of these circumstances, the present invention provides a member that regulates the maximum retard position of the injection timing control member based on a load-related signal in a distribution type fuel injection pump equipped with a timer that also has a load timer mechanism as described above. By changing the position of , the characteristics shown in FIG. 2 can be obtained.

Hereinafter, the present invention will be explained in detail with reference to Examples.

In the distribution type fuel injection pump shown in FIGS. 3 and 4, fuel is supplied from a fuel tank 1 to an engine-driven oil transfer pump 2.
The suction pressure is supplied to the suction space 4 in the pump housing 8.

Since the fuel oil pressure in the suction space 4 is controlled by the pressure control valve 5 in relation to the engine speed, as is well known, the oil pressure increases as the engine speed increases.

A pump/distribution plunger 7 is installed in a barrel 6 added to the pump housing 3, and this plunger 7 is caused to reciprocate and rotate at the same time by means described later.

That is, a drive shaft (not shown) and a cam disk 8 fixed to the end of the plunger 7 are connected in the rotational direction via the driving disk (not shown), and the number of cylinders of the engine formed on the cam disk 8 is adjusted. By pressing a cam surface having a corresponding number of peaks against a roller 10 held in a fixed roller holder 9 by a plunger spring (not shown), the plunger 7 is caused to reciprocate for sucking and pumping fuel; Rotation for distribution is performed at the same time.

When the plunger 1 is in the suction stroke (downward movement in FIG. 3), fuel in the suction space 4 flows from the suction hole 11 to the plunger γ.
It is supplied to the plunger chamber 13 through one of the plurality of vertical grooves 12 provided on the outer circumferential surface of the head.

When the plunger 7 moves to the pressure stroke (upward movement in FIG. 3), the suction hole 11 and the vertical groove 12 are separated and the plunger chamber 13
The fuel is compressed and supplied from the vertical hole 14 of the plunger 7 through the distribution vertical groove 15 to one of the discharge holes 17 (equally distributed in the number of cylinders in the circumferential direction) equipped with a check valve 16. Then, it is injected into the cylinder from an injection nozzle (not shown).

A control sleeve 18 is slidably inserted into the part of the plunger 7 that protrudes toward the suction space 4, and a cut-off boat 19 connected to the vertical hole 14 of the plunger 1 comes off the upper edge of the control sleeve 18 and draws suction. When the space 4 is opened, the fuel flows out into the suction space 4.
The delivery to the discharge hole 17 side is stopped, and the injection ends.

Therefore, by adjusting the position of the control sleeve 18, the end of injection can be changed, that is, the increase or decrease of the injection amount can be controlled.

Of the two levers 21 and 220 that are rotatable around a common support shaft 20, the lever 21 that is rotated by the action of the centrifugal speed governor 23 engages with the control sleeve 18.
A tension lever 22 disposed on this rotation side and subjected to the action of a governor spring 24 is engaged with the lever 21 via a start spring 25.

In the initial state, the tension lever 22 contacts the stopper pin 26 by the action of the governor spring 24 and the idle spring 51, and is set at the initial position.

Therefore, for example, if the engine speed rises above the set speed, the centrifugal governor 23 will move the sliding shaft 2 in relation to the engine speed.
The flyweights 29 in the flyweight holder 28, which rotate around seven rotations, are expanded, and at this time, the sleeve 30 is lifted and the levers 21, 22 are rotated clockwise in FIG. 3 to move the control sleeve 18 downward. Control is performed to reduce the injection amount and maintain it at the set rotation speed.

The governor spring 24 is connected eccentrically to the end of a rotating shaft 31, and a control lever 32 that is interlocked with an accelerator is attached to the rotating shaft 31.

Therefore, the spring force of the governor spring 24 that opposes the acting force of the centrifugal governor 23 can be strengthened in accordance with the accelerator position, and when the spring force is strengthened, the control sleeve 24 will not rotate more than that amount. 18 cannot be moved in the direction of decreasing the injection amount, in other words, the set rotation speed increases.

On the other hand, the roller holder 9 is provided so as to be rotatable concentrically with the plunger 7. One end of the lever 33 is connected to the roller holder 9, and the other end of the lever 33 engages with the piston 34.

At each end of the piston 34 there is a chamber 3 containing a spring 35.
6, and the oil pressure in the suction space 4 is connected to the through hole 37 of the piston 34.
A pressure oil chamber 38 is formed through which the pressure oil chamber 38 is guided, such that the position of the piston 34 and thus the circumferential position of the roller holder 9 via the lever 33 is determined in relation to the force of the spring 35 and the oil pressure. There is.

Then, due to the change in the circumferential position of the roller holder 9,
The contact position between the roller 10 and the cam surface of the cam disk 8 changes, and a relative change occurs between the circumferential phase of the drive shaft and the contact position, and hence the operating phase of the plunger 7. This causes a relative change in the injection timing with respect to the rotation of the drive shaft. can be changed.

In this case, the piston 34 is moved by the spring 3 due to hydraulic pressure.
5, the roller holder 9 is rotated counterclockwise and the injection timing is advanced.

Thus, as described above, the timer piston 34 drives the roller holder 9 and advances the injection timing due to the oil pressure in the suction space 4, which increases as the engine speed increases.

The oil pressure in the suction space 4 is also changed depending on the engine load, so that the injection timing is controlled depending on the load.

The load timer mechanism for this purpose is constructed as follows.

That is, inside the sliding shaft 27 of the centrifugal speed governor 23, one end communicates with a port 39 opened on the outer peripheral surface of the sliding shaft 27, and the other end communicates with the low pressure side of the oil pump 2 through a passage (not shown). A communicating escape hole 40 is bored, and a through hole 41 is bored through the sleeve 30 from its inner circumferential surface to its outer circumferential surface.

In a state where the levers 21 and 22 are directly engaged and the tension lever 22 is in contact with the stopper pin 26 (4/4 load), the sleeve 30 is in a sliding position with the through hole 41 of the sleeve 30. Although it does not match with the port 39 of the moving shaft 27, when the sleeve 30 moves upward in FIG. 3 and the tension lever 22 separates from the stopper pin 26 (partial load), the through hole 41 and the port 39 match,
A portion of the fuel in the suction space 4 flows through the through hole 41° port 39.
It escapes through the relief hole 40, so that the oil pressure in the space 4 decreases and the injection timing is delayed.

In the configuration according to the present invention, an eccentric pin 44 is engaged with a rotation shaft 43 rotatably supported by the housing 3 through a notch 42 provided in the roller holder 9.

A lever 45 is pivotally attached to a portion of the rotating shaft 43 that protrudes from the housing 3, and this lever 45 is connected to an output rod 47 of an electromagnetic actuator 46.

In the normal state (when not energized), this electromagnetic actuator 46 retracts the output rod 47, and the lever 45
Therefore, the eccentric pin 44 is moved to the position shown by the solid line.

On the other hand, a position detection coil 48 is fixed to the pump housing 3, and a part of a stroke body 50 that is pressed against the tension lever 22 by a spring 49 and follows the displacement of the lever 22 is inserted inside the coil.

As a result, when the tension lever 22 is displaced, the stroke body 50 moves within the position detection coil 43, the inductance of the coil 48 changes, and a voltage corresponding to this is output.

Therefore, the position of the tension lever 22 can be detected by the position detection coil 48, and a detection signal from the coil 48 is sent to a control circuit (not shown).

The control circuit determines whether the tension lever 22 has separated from the stopper pin 26 based on the detection signal.

When the user leaves, the electromagnetic actuator 46 is energized to operate it.

When the electromagnetic actuator 46 is energized, the output rod 47 is projected to the right in the figure, and the eccentric pin 44 is moved to the position shown by the broken line via the lever 45 and the rotating shaft 43.

According to this configuration, when the load is 4/4, the tension lever 22/I'i governor spring 24 is always pressed against the stopper pin 26, so the electromagnetic actuator 46 is not energized at this time, and therefore the eccentric pin 44 is not energized.
is at the position indicated by the solid line in the figure, and in the low rotation range, the eccentric pin 44 comes into contact with the side 42a of the notch 42 in the roller holder 9, rotating the roller holder 9 counterclockwise in FIG. 4, and reaching the maximum injection timing. It is set to the advance side, which is the delay time.

Moreover, at this time, the through hole 41 of the sleeve 30 and the port 39 of the sliding shaft 27 do not match, so that as the engine rotation increases, the injection timing characteristic shown by the solid line in FIG. 2 is obtained.

However, under a partial load, the tension lever 22 separates from the stopper pin 26, so the position detection coil 48
The electromagnetic actuator 46 is energized by the control circuit.

Therefore, the output rod 47 of the electromagnetic actuator 46 protrudes to the right in the figure, and the eccentric pin 44 is moved to the position shown by the broken line via the lever 45 and the rotation shaft 43. to retreat.

Therefore, the spring 35 acting on the piston 34 in the low rotation range provides a margin for further moving the roller holder 9 clockwise, that is, in the retard direction as shown in FIG. Can be set on the corner side.

Moreover, under partial load, the through hole 41 of the sleeve 30 and the port 39 of the sliding shaft 27 come to match, and a part of the fuel in the suction space 4 escapes through the escape hole 40.
Even if the rotation speed increases, the oil pressure in the suction space 4 is lower than when the rotation speed is the same under a 4/4 load. Therefore, for example, at an O/4 load, the injection timing will change as shown by the broken line in Figure 2. characteristics are obtained.

Here, the roller holder 9 is moved by the timer piston 34.
It is necessary to set the width of the notch 42 so that the opposite side 42b of the notch 42 does not come into contact with the eccentric pin 44 when the notch 42 is moved to the maximum retard position.

In this embodiment, the displacement of the tension lever 22 is detected as a signal related to the load, but the displacement of the control sleeve 18 or the control lever 32 may also be detected.

Further, the electromagnetic actuator 46 is not limited to an ON-OFF type, but may be operated in multiple stages or in a stepless manner depending on the load.

Furthermore, in addition to the load timer mechanism described in the above embodiments, there are other load timer mechanisms that use a pressure control valve 5 that is electrically activated by signals related to engine rotation and load. Of course, it can be applied.

As explained above, according to the present invention, it is possible to obtain an injection timing that corresponds to the rotational speed and load, and when the rotational speed is constant, the injection timing can be delayed at partial load, and in the low rotational range, the injection timing can be delayed. The maximum retard position can also be changed depending on the load.

Therefore, great effects can be achieved in countermeasures against the emission mode region and idle noise.

[Brief explanation of drawings]

Figure 1 is an injection timing characteristic diagram using only the conventional road timer mechanism, Figure 2 is an ideal injection timing characteristic diagram,
FIG. 3 is a front partial vertical sectional view showing an embodiment of a distribution type fuel injection pump to which the present invention is applied, and FIG. 4 is a line A-A in FIG. 3.
It is an arrow sectional view. 2...Oil pump, 3...Pump housing, 7...Plunger, 8...Cam disc, 9...Roller holder, 18...
...Control sleeve, 21.22...
Lever, 23...Centrifugal governor, 24...
・Governor spring, 26...stopper pin,
32...Control lever 34...
・Timer piston, 38...Pressure oil chamber, 40・
...Escape hole, 42...Notch, 43.
... Rotation axis, 44 ... Eccentric pin, 45.
...Lever 47 ...Output lot, 48
...Position detection coil, 50...Stroke body.

Claims (1)

[Scope of utility model registration request] In a distribution type fuel injection pump that controls injection timing by driving an injection timing control member by a timer piston that responds to oil pressure that changes in relation to engine rotation and load, the maximum retardation of the injection timing control member An engaging member is provided that engages in one direction to regulate the position, and an electromagnetic actuator is provided that connects the engaging member to the output lot and moves it in response to a signal related to the engine load. An injection timing adjustment device for a distribution type fuel injection pump, characterized in that the maximum retardation position of an injection timing control member is changed.