JPS58174123A - Distributor type fuel injection pump for diesel engine - Google Patents

Abstract

PURPOSE:To correct a full load injection amount, by changing a spill ring externally fitted to a plunger of an injection pump in accordance with a rotary speed of the pump. CONSTITUTION:A plunger 35 of a full load injection amount corrective mechanism 30 is placed in a stationary state to a position in which internal pressure of a pump chamber 41 and urging force of a spring 44 are balanced. If a rotary speed of a pump increases, the plunger 35 is lifted to control a spill ring 11 through a cam 34, connecting pin 38 and control arm 40.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a distributed fuel injection pump for a diesel engine.

A fuel injection pump is used to inject a predetermined amount of fuel at a predetermined time and at a high pressure into nine cylinders provided in each cylinder of a diesel engine. Fuel injection pumps can be roughly divided into two types: line-panel type and distribution type.

An example of the latter is shown in the cross-sectional view of FIG. 1.

In FIG. 1, the fuel injection pump is
2. A feed pump that sucks up a certain amount of fuel per rotation from the drive shaft IK. A gear 3 and a roller 4 are provided at the end of the drive shaft 1. A governor 5 driven by a gear 3, a pump plunger 7 which is rotatably arranged coaxially with the drive shaft 7 and distributes fuel to the distribution passage 6, and a drive shaft IK: the pump plunger is connected via a coupling. 7. Cam plate driving 8. The same number of face cams as the head Kx engine cylinders of the cam plate 8 are provided. A plunger spring 10 applies a predetermined biasing force to the drive shaft 1 of the cam plate 8, and a spill ring 11 is fitted onto the end of the pump plunger 7 and leaks the fuel inside the plunger from the spill port 21 at a predetermined time. A governor lever 12 that moves the spill ring 11 in the axial direction with one ring of levers by the driving force of the governor 5. A spring 13 that applies a predetermined biasing force to the governor lever 12 in the governor direction. an adjusting lever 14 for adjusting the tension of the spring 13; A fail-cut solenoid 15° that shuts off or opens the fuel sent from the pump chamber to the pump plunger 7. A regulating valve 17 that adjusts the fuel sending pressure of the feed pump 2. Drive shaft 1
A timer piston 18 and a delivery valve 19 are arranged perpendicularly to the timer piston 18 and slide within the timer housing and rotate a cylindrical face cam via a slide bin 17 due to a combination of changes in the oil pressure and the biasing force of the timer spring 16.
．． The feed pump cover is constructed with a 20° angle.

The operation of the fuel injection pump with the above configuration will be explained next. The fuel sucked up by the feed pump 1 is sent under pressure into the pump chamber through a hole in the upper part of the feed pump cover 20 on the discharge side of the feed pump. The pump plunger 7 is driven by a cam plate 8 and is pressed against the cam plate 8 by a plunger spring 10. t+, cam play) 8 is rotationally driven by a drive shaft IK, so that it reciprocates on the fixed roller 4 by a specified cam lift.

This is K, plunger 7 connected to cam plate 8.
makes a reciprocating motion together with rotational motion, and after sucking in fuel, performs distribution and pressure feeding, and injects the fuel at high pressure to the injection nozzle via the distribution passage and the delivery valve 9. The pumping of fuel begins when the plunger 7 begins to rise and the vehicle is running, and the pumping of fuel ends when the plunger 7 further rises and the spill port 21 is exposed from the right end surface of the spill ring into the pump chamber.

Governor 5 is an example of a centrifugal all-speed governor.
It has a function of controlling the fuel injection amount by moving the spill ring 11 blocking the spill port 21. 't. A hydraulic timer (consisting of a timer spring 16°, a slide bin 17, and a timer piston 18) built into the lower part of the injection pump is activated by the fuel pressure in the pump chamber, and the timer moves a roller ring (not shown). to advance the angle and control the injection timing. Sara K.

The fail cut-off renoid 15 is connected to an ignition switch (not shown), and when the ignition switch is turned to OFF, the current is cut off and the valve is closed, cutting off the fuel and stopping the engine.

By the way, in the conventional injection pump as described above, the relationship between the spill ring position and the pump rotational speed is determined by the amount of fuel that the injection pump pumps under full load (in other words, the relationship between the spill ring position and the pump rotational speed is The spill position) has a nearly constant characteristic regardless of the pump rotation speed (in other words, the rotation speed t > rs).On the other hand, the amount of air taken into the engine varies depending on the engine rotation speed. Conventionally, no consideration has been given to how to respond to such fluctuations in intake air with respect to the amount of fuel.As a result, fuel injection is not performed in proportion to the amount of intake air, resulting in a situation where intake air is insufficient. Ninthly, in the past, the air-fuel ratio at full load could not be kept constant, or the intake air could not be used sufficiently, so the rotation region or intake There was a drawback that there were operating areas where a large amount of smoke was generated due to lack of air.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a distribution lid fuel injection pump for a diesel engine, which allows an arbitrary full-load fuel injection amount to be set for the rotational speed of the pump and eliminates the above-mentioned conventional drawbacks.

The present invention provides a distribution type fuel injection pump in which the injection amount of #a fuel is adjusted by moving a spill ring fitted onto a spill port portion of a plunger. K is adjusted to obtain the desired full load injection rate.

FIG. 3 is a sectional view showing an embodiment of the present invention.

In Fig. 3, parts K having the same functions as those shown in Fig. 1 are given the same reference numerals, and the same mechanisms are shown except for the parts added to the new nine, so the overall operation will not be explained. omitted.

In this embodiment, a full-load injection amount correction mechanism 30 is added that corrects the movement of the spill ring according to the pump rotation speed. The full load injection amount correction mechanism 30 is.

A cylinder 33 having a low pressure chamber 31 and a high pressure chamber 32; a plunger 35 which is slidably housed within the cylinder 33 with a seal ring 34 fitted thereon; A bushing rod 36 attached to the pump chamber side of the plunger 35. Cam 3 is attached to the tip of the skeleton rod 36, on the outer periphery of the skeleton cam 37! contact.

A connecting pin 38 in a right-angled direction according to its shape, a control arm that constantly contacts the pin 38 and the rod 36 and transmits the reciprocating motion of the pin 38 to the end of the tension lever 39 that constitutes the governor lever 121 at full load. 40. A passage 42 connecting the high pressure 1 m32 and the pump chamber 41. A passage 43 connecting the low pressure chamber 31 and the pump inlet (or fuel tank, etc.). Each of the springs 44 provided in the high pressure chamber 31 and pressing the plunger 35 is configured as a main member.

FIG. 4 is a configuration diagram showing details of the full load injection amount correction mechanism 30. The operation of the embodiment shown in FIG. 3 will be explained based on FIG. 4.

When the rotational speed of the pump increases, the oil pressure in the pump chamber 41 increases, and the plunger 35 moves in the direction A in the figure until it balances with the biasing force of the spring 44.

Conversely, when the rotational speed of the pump decreases, the plunger 35 moves in the direction B and stops at the balance position. In this way, the pump 35 comes to rest at a position where the internal pressure of the pump chamber 41 and the biasing force of the spring 44 are balanced. This plunger 35 is equipped with a cam 37 having an uneven shape on its outer periphery. The connecting bin 38 is driven in accordance with the movement of the jar 35. The control arm 40, which is driven by the pin 38, is pulled toward the cam 37 by a spring 45, and when the rod 36 and the pin 38 are in contact, a constant amount is applied.
The shaft in contact with the cam 37 rotates about the fulcrum 46 by an amount determined by the wall thickness of the cam 37. In response to this rotation, the tension lever 39 moves VCl2 about the fulcrum 47, and when fully loaded, it is moved by the drive force of the governor 50 according to the surface shape of the cam 37, independent of the control of the spill ring 11 by the Salel control lever 48. The spill ring 11 can be controlled as follows. Next, the guide lever 49 is at the fulcrum 50.
It is fixed to the housing by a screwdriver and is used to adjust the position of the spill ring 11. Since spilling correction control at full load is uniquely determined by the shape of the cam 37, desired injection characteristics can be achieved simply by changing the cam shape. Incidentally, in order to smoothly operate the connecting bin 38, a roller 51 may be provided on the surface that contacts the cam 37 as shown in FIG.

FIG. 6 is a configuration diagram of a full-load injection amount correction mechanism 30 showing another embodiment of the present invention. In this example, the tension lever 3
9, the plunger mechanism and the fuel injection pump are connected through a link connection. That is, the low pressure chamber 6
A plunger 64 connected to a rod 63 is accommodated in a cylinder 62 having a high pressure chamber 61 and a spring 65 provided in a low pressure chamber 60 to apply an urging force to the plunger 64.

A seal ring 66 is attached to the outer circumference of the plunger 64 to ensure low pressure! 160 degrees of airtightness. The internal pressures of the low-pressure chamber 60 and the high-pressure chamber 61 vary depending on the rotational speed of the pump, and the plunger 64 moves in response to this variation and stops at a position where it balances with the spring 65.

On the other hand, the tip of the tension lever 39 is extended relative to the structure shown in FIG. 4, and the roller 67 is attached to the head. A disc-shaped cam 68 having an uneven surface is rotatably fixed to this row 267. In this case, the uneven portion is the cam 3 mentioned above.
7, it is formed so as to be in contact with the o-ra 67 at full load, and has a shape that can correct the blowout resistance characteristics. moreover,
A rod 69 is fixedly connected to the shaft portion of the cam 68, and the cam 68 rotates by an amount corresponding to the rotation angle of the rod 69. The end of the rod 69 is linked to the end of the rod 63, and the reciprocating motion of the plunger 64 is transmitted through the rod 69 to the cam 68.
The rotational movement of the cam 68 is transmitted through the IC.

In addition, in each of the above embodiments, four plungers 3
5. Fit the 61C sealing ring externally.

Although the airtightness of each pressure chamber is shown in FIG. 9, it is not necessary to provide this sealing ring if a decrease in response is acceptable.

9. In the above embodiment, when moving the spill ring under full load, the tension lever was driven by a plunger mechanism, but instead of being driven by a plunger, it could be driven by an electromagnetic mechanism using a linear solenoid or the like. In this case, the fuel pressure inside the pump is detected by a sensor.

Alternatively, the rotation of gear 3 is detected by an electromagnetic vibrator or the like.

The solenoid may be driven according to this detected amount.

As is clear from the above, according to the present invention, it is possible to make the fuel injection amount characteristic with respect to the pump rotational speed tK of the distribution cover fuel injection pump for a diesel engine a desired characteristic.
It is possible to effectively draw out the power available in the engine and improve the drivability of the vehicle.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a conventional distribution fuel injection pump for diesel engines, Figure 2 is a spill ring position characteristic diagram with respect to pump rotation speed of a distribution type fuel injection pump, and Figure 3 is an embodiment of the present invention. FIG. 4 is a configuration diagram showing details of the full-load injection amount correction mechanism 30 shown in FIG. 3, and FIG. 5 is a front view showing another example of the connecting pin 38 shown in FIG. 4. FIG. 6 is a configuration diagram showing another example of the full-load injection amount correction mechanism 30 according to the present invention. l...Drive shaft, 2...Feed pump, 5...Governor, 7...Pump plunger. 8...Cam plate, 11...Spill ring. 12... Governor lever +, 13, 44.65... Suzu ring, 18... Tie! Piston, 21...
・Spill boat, 30...Full load injection amount correction mechanism. 31.60...Low pressure iii% 32,61...High pressure! 1゜93.62...Cylinder, 34.66...Seal ring, 35.64...Plunger,
36・°'butsu shitsudo, 3), 68...cam, 38...connecting pin, 39...
Ten 7th lever. 40...° control arm, 411° bonf chamber. 46.47--Fully point, 48--Control lever. 51.67...Roller, 63.69・°・Rod. -1'/ Figure 1 Figure 2 E) 7° rotation speed → Figure 3 Figure 6

Claims (1)

[Claims] (1) A pump plunger that distributes and pressure-feeds fuel to nine injection nozzles provided for each cylinder by driving a cam mechanism, a spill ring that is movably fitted onto a spill port provided on the plunger, and a lever mechanism. In the distribution type fuel injection pump for a diesel engine, the fuel injection pump for a diesel engine is equipped with at least a governor mechanism that changes the amount of movement of the spill ring according to the pump rotational speed via Subi /l/ that drives the tension lever that makes up the mechanism
A distributed fuel injection pump for diesel engines, characterized by being equipped with an IJ song position correction mechanism. (2. In claim 1, the tension lever is driven by a plunger mechanism that moves a cam having a surface shape that matches the injection amount correction characteristic in accordance with the number of revolutions.) A distribution type fuel injection pump for a diesel engine, characterized in that: 0) Claim 1 provides that the tension lever is driven by a solenoid in accordance with the injection amount characteristics. Distribution type fuel injection pump for diesel engines.