JPH0550581B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a fuel injection device, and in particular to a fuel injection device that allows fuel flow characteristics to be set arbitrarily and that also facilitates setting and achieves an engine-required fuel flow rate. Regarding equipment.

[Technical Background of the Invention] An internal combustion engine, such as a diesel engine, is an engine that compresses only air and injects fuel into a hot cylinder to self-ignite. Equipped with a fuel injection device for injection.

This fuel injection device consists of a fuel injection system consisting of an injection pump and an injection timing regulator to inject the appropriate amount of fuel at the right time, and a control system consisting of a speed governor to stabilize engine rotation. ing.

FIGS. 1 and 2 are partial sectional views showing a control system of a conventional fuel injection device. The fuel injection amount is controlled by changing the plunger stroke at which the cut-off port 4 of the plunger 2 is closed by operating the spill ring 6. The spill ring 6 is engaged with one end of a support lever 10 that interlocks with the tension lever 8, and by swinging the tension lever 8 with an accelerator lever 12, the spill ring 6 is moved in the axial direction of the plunger 2. Idle spring 1
4 increases the fuel injection amount by pushing back the tension lever 8 when the engine is idling.

In FIG. 1, when the accelerator lever 12 is turned to the fully open position, the idle spring 14 is compressed.
The tension lever 8 rotates in the direction of arrow a around the governor pin 15, and comes into contact with a stopper 16 and stops. At this time, since the reverse Angleich spring 20 of the control lever 18 is not compressed, the fulcrum 22 and the rod tip 24 both come into contact with the tension lever 8, and the spill ring 6 is kept at a constant position. Therefore, the spill ring 6 moves a certain distance in the direction of the arrow b, that is, the pressure stroke S1
and increases to the predetermined injection amount.

When the rotational speed further increases from the above state, the flyweight 26 opens in the direction of arrow c, as shown in FIG. 2, and propels the governor sleeve 28 toward the control lever 18. When this thrust becomes larger than the spring load of the reverse Angleich spring 20,
The control lever 18 rotates about the fulcrum 22 in the direction of arrow d. Therefore, support lever 1
0 also rotates around the support shaft 7 in the direction of arrow d, and further moves the spill ring 6 in the direction of arrow b to increase the injection amount. The amount of increase at this time is determined by the stroke S2 in which the control lever 18 moves by compressing the reverse Angleich spring 20.

[Problems in the Background Art] As described above, the conventional fuel injection device prevents the injection amount from decreasing due to leakage from around the plunger 2 on the low-speed side of the engine, or due to fluid resistance on the high-speed side, by using the idle spring 14 or the reverse side. This is compensated for by the Angleich spring 20, etc., and the fuel flow rate characteristics at full load as shown by the thick line in FIG. 3 are obtained.

However, since the spring load of the spring is used for its operation, only a linear flow characteristic as shown in the figure can be obtained.

Further, the tension lever 8 and the support lever 10 are pivotally supported by a collector lever 30, and the collector lever 30 is pivotally supported by a support shaft 32 on the housing side of the fuel injection device. Then, a collector spring 34 is interposed on one side with the support shaft 32 in between, and an adjustment screw 36 is brought into contact with the other side, and the collector lever 30 is adjusted by this adjustment screw 36, and the flow rate at full load is adjusted. was set.

However, since adjustment using the adjustment screw 36 requires rotation, it is not possible to simply change the set flow rate to respond to changes in engine load.

Furthermore, the collector lever was adjusted using the pressure inside the fuel injection device, and the
Some of these are disclosed in Japanese Patent Application Laid-open No. 66640 and Japanese Patent Application Laid-Open No. 174124/1983.

However, in the method disclosed in Japanese Patent Application Laid-open No. 55-66640, the cam is moved linearly by pressure, and the cam surface is provided with the same length as the cam that is pivotably supported. However, there is a disadvantage that the amount of movement of the cam becomes large, and a large amount of pressure is required to ensure such a large amount of movement. However, the operation of the cam is easily affected by pressure fluctuations, and the collector lever is unnecessarily swung, resulting in a disadvantage in that the reliability of the operation is impaired.

In addition, in the device disclosed in Japanese Patent Application Laid-open No. 58-174124, the cam is rotated by pressure, but in order to convert the linear movement of the plunger in the cylinder into rotational movement and transmit it to the cam, Providing a push rod increases the number of parts and complicates the structure. In addition, since different pressures are applied to each end of the plunger, the operation of the plunger is adjusted. This has the disadvantage that it is difficult to

As described above, in the past, fuel flow characteristics were linear and the fuel flow rate could not be easily set, making it impossible to achieve the flow characteristics required by the engine. In addition, even if the collector lever is adjusted by pressure, there are disadvantages such as requiring a large pressure and impairing the reliability of operation, as well as complicating the structure and making it difficult to adjust the operation. Ta.

[Specific Object of the Invention] Therefore, an object of the present invention is to enable the fuel flow characteristics to be arbitrarily set in order to achieve the engine-required fuel flow rate, to easily set the fuel flow rate, and to improve the operational efficiency. The object of the present invention is to realize a fuel injection device with a simple structure that can ensure reliability.

[Structure of the Invention] In order to achieve this object, the present invention causes the tension lever to be oscillated by the accelerator lever, and the governor sleeve to be moved forward and backward by the engine speed to oscillate the support lever via the control lever. In a fuel injection device that operates a spill ring by swinging a tension lever and a support lever to control the fuel injection amount, a collector lever is provided that pivotally supports the tension lever and the support lever, and the collector lever is adjusted. An adjustment shaft is provided with one end in contact with the adjustment shaft, and a cam is provided on one end side with a cam surface of a predetermined shape that is in contact with the other end of the adjustment shaft. The other end of the cam is connected to an actuator so that the cam is actuated by the pressure within the fuel injection device, and the actuator slides the piston into the main body. A spring is interposed in the main body at one end of the piston, and a pressure chamber for introducing the pressure inside the fuel injection device is provided at the other end of the piston, and a support hole for the piston is provided. The present invention is characterized in that a support end holder is slidably attached to the support end holder, and the cam support end on the other end side of the cam is rotatably held in the support end holder.

[Embodiments of the Invention] Next, embodiments of the invention will be described in detail based on the drawings. FIG. 4 is a partial sectional view of the control system of the fuel injection device according to the present invention. In the figure, the first
The same parts as in Figures 2 to 2 are given the same reference numerals.

That is, the spill ring 6 attached to the plunger 2 adjusts the plunger stroke at which the cut-off port 4 is closed, and controls the injection amount.
This spill ring 6 is engaged with one end of the support lever 10.

The support lever 10 swings around the governor pin 15 together with the tension lever 8, and moves the spill ring 6 in the axial direction of the plunger 2. These tension levers 8 and support levers 10
is pivotally supported by the collector lever 30.

The collector lever 30 is pivotally supported by a support shaft 32 on the housing side of the fuel injection device. A governor pin 15 is biased from the support shaft 32 and pivotally supports the tension lever 8 and the support lever 10.
is provided.

The collector lever 30 has a collector spring 34 compressed on one side with the support shaft 32 in between, and the collector lever 30 is adjusted in the direction opposite to the elastic force of the collector spring 34 on the other side, as shown in FIGS. 1 and 2. A screw 36 is provided, and the flow rate is set by adjusting the collector lever 8 by rotating the screw.

In this invention, the adjustment shaft 38 for adjusting the collector lever 8 is provided so as to be movable back and forth by a cam 40 having a predetermined shape, and the cam 40 is operated by pressure within the fuel injection device.

Further details will be explained. Collector lever 30
An adjustment shaft 38 is provided at a position opposing the elastic force of the collector spring 34 with the support shaft 32 in between. The adjustment shaft 38 is connected to the housing 4 of the fuel injector.
2 so as to be slidable in the axial direction, and one end is in contact with the collector lever 30. The other end of the adjustment shaft 38 is in contact with a cam 40 having a cam surface 44 of a predetermined shape.

The cam 40 is provided to be swingable by a cam shaft 46. With this camshaft 46 in between, the cam 4
The cam surface 44 is provided on one end of the cam 40, and the other end is connected to an actuator 48 for actuating the cam 40.

The actuator 48 has a piston 52 built into the main body 50. A spring 54 is interposed between one end of the piston 52 and the main body 50, and a pressure chamber 56 is partitioned and provided at the other end. This pressure chamber 56 communicates with the inside of the fuel injection device and pressure is introduced into it. A support hole 58 formed in the piston 52 is slidably fitted with a support end holder 62 that rotatably holds a cam support end 60 .

Next, the effect will be explained.

When the engine speed increases and the fuel pressure within the fuel injection device increases, the pressure in the pressure chamber 56 of the actuator 48 increases. As the pressure in the pressure chamber 56 increases, the piston 52 moves in the direction of arrow e against the spring 54, and rotates the cam 40 in the direction of arrow f. With this rotation, the adjustment shaft 38 that abuts the cam surface 44 moves back and forth in the direction of the arrow x depending on the shape of the cam surface 44 that it abuts. As the adjustment shaft 38 moves back and forth, the collector lever 30 swings about the support shaft 32 and moves the spill ring 6 in the axial direction of the plunger 2. This movement changes the pumping stroke at which the cut-off port 4 of the plunger 2 is closed, increasing or decreasing the injection amount.

At this time, the tension lever 8 that is linked to the accelerator and the support lever 1 that operates at high speed rotation are activated.
Coupled with the zero operation, it is possible to set an injection amount suitable for the engine speed. That is, when the tension lever 8 or the support lever 10 is operated, the cam 40 is actuated by the actuator 48 which introduces fuel pressure in the fuel injection device corresponding to the engine speed, and the collector lever 30 is oscillated. Since the injection amount is set based on the shape of the cam surface 44, it is possible to set the flow rate characteristic to any desired value depending on the shape of the cam surface 44. Also, the setting can be easily made by simply changing the shape of the cam surface 44, so that the injection amount can be set according to the engine's requirements. It is possible to achieve fuel flow characteristics that

When the engine speed decreases and the pressure in the pressure chamber 56 decreases, the piston 52 rotates in the direction of arrow g.
This rotation causes the adjustment shaft 38 to move back and forth in the direction of the arrow x along the cam surface 44, swinging the collector lever 30 and moving the spill ring 6 in the axial direction of the plunger 2. Then, as described above, the actuator 48 operates the cam 40 to release the collector lever 3.
0 is oscillated, the injection amount is increased or decreased depending on the shape of the cam surface 44, and the injection amount is set in succession with the tension lever 8 and the support lever 10.

[Effects of the Invention] As described above, according to the present invention, a cam of a predetermined shape is actuated by the actuator using the pressure within the fuel injection device, and the collector lever is adjusted by the adjustment shaft that moves forward and backward by the operation of this cam. , the flow rate characteristics can be set to any desired value depending on the shape of the cam surface. Furthermore, the fuel flow rate can be easily set to any desired flow rate by changing the shape of the cam surface.

In this way, the flow rate characteristics can be arbitrarily and easily set, and since the collector lever is adjusted based on the pressure inside the fuel injection system, the engine can achieve the required fuel flow rate depending on the full load or load condition, improving output. can be achieved.

Further, without directly operating the cam with pressure, the reciprocating motion of the piston is converted by a support end holder that holds the cam support end and transmitted to the cam, causing the cam to swing. Therefore, it is less susceptible to pressure fluctuations, prevents unnecessary rocking of the collector lever, ensures reliable operation, and simplifies the structure without increasing the number of parts. can be accomplished.

In addition, in the device according to the present invention, the adjustment shaft and cam that adjust the collector lever, and the actuator that operates this cam by the pressure inside the fuel injection device can be attached to an existing fuel injection device and used. It is.

[Brief explanation of the drawing]

Figures 1 and 2 show the control system of a conventional fuel injection device. Figure 1 is a partial sectional view of the accelerator lever in the fully open position, Figure 2 is a partial sectional view of the governor sleeve in the forward position, and Figure 3 is a conventional device. It is a figure which shows the graph of the fuel flow characteristic of. FIG. 4 is a partial sectional view of the fuel injection device according to the present invention. In the figure, 2 is a plunger, 6 is a spill ring, 8 is a tension lever, 10 is a support lever, 26 is a fly weight, 28 is a governor sleeve, 30 is a collector lever, 38 is an adjustment shaft, 40
is a cam, 44 is a cam surface, 48 is an actuator,
56 is a pressure chamber.

Claims (1)

[Claims] 1 The tension lever is oscillated by the accelerator lever, and the governor sleeve is moved forward and backward depending on the engine speed, and the support lever is oscillated via the control lever, and the spill ring is actuated by the oscillation of the tension lever and the support lever. A fuel injection device that controls the amount of fuel to be injected is provided with a collector lever that pivotally supports the tension lever and the support lever, an adjustment shaft that abuts one end to adjust the collector lever, and an adjustment shaft that contacts the other end of the adjustment shaft. A cam having a cam surface of a predetermined shape on one end side that comes into contact with the adjustment shaft is provided, and the cam is swingably supported by a cam shaft so that the adjustment shaft can be moved forward and backward by the cam, The other end of the cam is connected to an actuator so as to be actuated by the pressure within the fuel injection device, and the actuator has a piston slidably built into its main body, and one end of the piston is located inside the main body. A pressure chamber is partitioned and provided at the other end of the piston to introduce the pressure in the fuel injection device, and a support end holder is slidably attached to the support hole of the piston, and a spring is interposed therebetween. A fuel injection device characterized in that a cam support end on the other end side of the cam is rotatably held in a support end holder.