JPH03260340A - Fuel injection device for internal combustion engine - Google Patents

Abstract

PURPOSE:To control mechanically a forced fuel supply start timing for getting a desired angle advancing property by providing a fuel injection pump having a sleeve control means or the like and a mechanical governor having a means or the like for adjusting the position of the control means in a desired firing timing. CONSTITUTION:When the rotational speed of a fuel injection pump 2 in a fuel injection device 1 is low for example, the rotational speed of the fuel injection pump 2 is increased in proportion to the rotational speed of a Diesel engine, while the stroke of a mechanical governor 5 is varied. Simultaneously, the other end of a floating lever 62 in a injection timing control mechanism 6 is shifted leftward by a shift amount corresponding to a weight stroke, while the lever 62 is rotated clockwise about a pivot 62c. As a result, a control lever 64 is shifted rightward to rotate a cam 65 about an eccentric shaft 65c. Since, however, the cam 65 does not vary the position of a stopper 45, a timing control rack 4 is also held in a predetermined position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection device for an internal combustion engine, and particularly to a fuel injection device for a teasel engine used in a variable prestroke fuel injection pump.

[Prior Art] Japanese Utility Model Application Publication No. 63-196442 discloses a control 81 for controlling the axial position of a control sleeve that changes the fuel pumping start timing (injection timing) according to the axial position. ing. This control I! On the side, a control member that changes the axial position of the control sleeve is operated by a hydraulic actuator. This hydraulic actuator is controlled by a microcomputer based on detected values such as the rotational speed of the internal combustion engine.

Furthermore, the control mechanism disclosed in Japanese Utility Model Application Publication No. 63-196443 includes a flyweight whose centrifugal force changes depending on the rotational speed of the fuel injection pump, and an axial direction that changes in the centrifugal force of the flyweight. This utilizes a mechanical governor that has a displacement member that moves back and forth. That is, this control mechanism controls the axial position of the control sleeve by transmitting the amount of axial displacement of the displacement member related to the centrifugal force of the flyweight to the control member via the cable.

[Problems to be Solved by the Invention] However, the former control mechanism is expensive because it uses an expensive system such as a microcomputer that controls the hydraulic actuator.

Furthermore, in the latter control mechanism, it is not specifically disclosed how the displacement member, cable, and control member are connected, and how they are arranged relative to the mechanical governor. It was not possible to materialize the structure of the latter control mechanism.

Furthermore, when the rotational speed of the internal combustion engine is in a low speed range, in order to stabilize the ignition of the fuel, it is necessary to advance the timing of starting the pumping of fuel with respect to the crank angle of the internal combustion engine. Further, in a high speed range, it is necessary to advance the timing of starting the pumping of fuel in consideration of the fuel consumption rate.

However, in the latter control mechanism, the fuel pumping start timing becomes earlier in accordance with the rotational speed of the fuel injection pump, so it is not possible to obtain advance angle characteristics that can satisfy the above-mentioned requirements. 6. It is an object of the present invention to provide a fuel injection device for an internal combustion engine that can mechanically control the timing at which fuel υ starts to be pumped and can also be controlled so as to obtain a desired advance angle characteristic.

[Means for Solving the Problems] A fuel injection device for an internal combustion engine according to the present invention includes a plunger that is reciprocated in the axial direction by the internal combustion engine and pumps fuel, a plunger that is slidably disposed around the outer circumference of the plunger, a fuel injection pump having a sleeve that changes the timing at which fuel pumping starts depending on the axial position, and a control means that is connected to the sleeve and changes the axial position of the sleeve in response to the change in the position; A flyweight whose centrifugal force changes according to a change in the rotational speed of the internal combustion engine, a displacement means connected to the flyweight and which moves in response to a change in the centrifugal force of the flyweight, and the control means and the displacement means. interposed between the control means and the shifting means, and positioning the control means with respect to the shift of the shifting means to a position corresponding to a desired ignition timing with respect to the crank angle of the internal combustion engine. A mechanical governor with adjustment means was adopted.

[Function] The centrifugal force of the flyweight of the mechanical governor increases as the rotational speed between the internal combustion engines increases, and decreases as it decreases. Then, the shifting means shifts in accordance with the amount of increase or decrease in the centrifugal force of the flyweight. Next, when the adjusting means is driven by the displacement of the displacement means, and the position of the control means also changes, the position of the control means is determined by the adjustment means according to the amount of displacement of the displacement means of the internal combustion engine. The position is adjusted to correspond to the desired ignition timing relative to the crank angle. This lick,
The axial position of the sleeve also corresponds to the displacement amount of the displacement means, that is, the desired ignition timing with respect to the rotational speed of the internal combustion engine.

Therefore, the timing of starting the pumping of fuel is controlled so as to have a desired advance characteristic with respect to the crank angle of the internal combustion engine.

[Effects of the Invention] It is possible to mechanically control the timing to start pumping fuel, that is, the ignition timing. This eliminates the need for an expensive system such as a microcomputer, resulting in lower costs than conventional devices.

The fuel pumping start timing can be controlled so as to obtain desired advance angle characteristics with respect to the crank angle of the internal combustion engine with respect to the rotational speed of the internal combustion engine. Therefore, for example, stable ignition can be achieved when the rotational speed of the internal combustion engine is in a low speed range, and the fuel consumption rate can be reduced in a high speed range.

[Example] A fuel injection device for an internal combustion engine according to the present invention will be explained based on an example shown in FIGS. 1 to 8.

1 to 4 show a first embodiment of the invention. 1st
The figure is a diagram showing essential parts of a diesel engine fuel injection device 6 The diesel engine fuel injection device 1 includes a fuel injection pump 2 and an all-speed mechanical governor 5.

The fuel injection pump 2 is a variable pre-stroke type fuel injection pump, and pumps the fuel supplied inside to a high-pressure pipe connected to the fuel injection pump 2 and a nozzle attached to each combustion chamber of the diesel engine. It is something.

This fuel injection pump 2 includes a drive mechanism 21, a cylinder 22
, a plunger 23, a control sleeve 24, an injection amount control rack (not shown), and a timing control rack 4.

Drive 8! The ellipse 21 has a camshaft 25 and a tappet 2.
The 6 camshaft 25 having 6 is rotationally driven by a diesel engine, and by rotating the cam 27, the tappet 26 is rotated.
The first langeer 23 is caused to reciprocate through the .

Further, the cam shirt 25 rotates the mechanical governor 5 in accordance with the rotational speed of the diesel engine.

The cylinder 22 has a fuel discharge port 28 formed at its upper end;
and has a shaft hole 29 formed inside.

The plunger 23 has a tubular shape and has a shaft hole 2 of the cylinder 22.
9 and is reciprocated in the vertical direction by a cam 27. This plunger 23 has a shaft hole 3 formed inside.
0, a lead 31 connected to this shaft hole 30 and formed on the outer periphery
, and a boat 32 that communicates with the shaft hole 30 and is formed below the lead 31 in the drawing.

The leads 31 are inclined at a predetermined angle so as to point upwardly to the right. The shaft hole 30 and the lead 31 act as a discharge passage for discharging the fuel in the shaft hole 29 of the cylinder 22 when the hole 33 of the control sleeve 24 and the lead 31 match (completion of pressure feeding). , serves as a supply passage for supplying fuel from the surroundings through the shaft hole 30 into the shaft hole 29 of the cylinder 22 . In addition, the plunger 23
Ha, jet! Rotation is controlled by a control rack, and since the reed 31 is upwardly tilted to the left, rotating to the left decreases the injection amount, and rotating to the right increases the injection amount.

The control sleeve 24 is a sleeve of this embodiment, has an annular shape, is disposed on the outer periphery of the plunger 23 so as to be slidable in the axial direction, and has a hole 33 that communicates the inner periphery with the outer periphery.
and a fitting groove 34 connected to the timing control rack 4 on the outer periphery.

When the timing control rack 4 rotates to the left, the control sleeve 24
is lowered to reduce the pre-stroke and start pumping fuel earlier. Moreover, the control sleeve 24 is
When the timing control rack 4 rotates clockwise, the control sleeve 24 rises, increasing the pre-stroke and delaying the start of pumping fuel. Pre-stroke means that the plunger 23 moves from the bottom dead center to the bottom of the boat 32.
refers to the amount of movement until the control sleeve 24 is closed by the inner wall of the control sleeve 24.

The timing control rack 4 is the control means of this embodiment, and has a control sleeve 24 fitted 7 on its outer periphery.
A pin 41 that is fitted into the 1t34 is disposed, and a stopper 42 that rotates integrally with the outer periphery of the end is fitted. The stopper 42 is pressed toward the injection timing controller 1116 of the mechanical governor 5 by a safety spring 43.

The timing control rack 4 rotates in the direction of the arrow in the figure to change the axial position of the control sleeve 24, thereby controlling the timing at which fuel pumping starts.

The mechanical governor 5 includes flyways 1 to 51, a shifter 52, an injection amount control i-ellipse (not shown), and an injection timing control mechanism 6.

The flyweight 51 has a well-known structure, with one end connected to the cam shirt 1-25 and the other end connected to the injection amount control mechanism and the injection timing control mechanism 6 via a shifter 52. When the centrifugal force corresponding to the rotational speed of the camshaft 25, that is, the rotational speed of the fuel injection pump 2, overcomes the spring force of the spring 53 disposed on the outside, the flyweight 51 generates a force as shown in the graph of FIG. , changes the displacement amount (weight stroke) of the injection amount control mechanism and the injection timing control mechanism 6. Note that 54 is a housing of the mechanical governor 5.

The injection amount control mechanism controls the position of the injection amount control rack with respect to the rotational speed of the fuel injection pump 2 as shown in the graph of FIG.

In the graph of FIG. 3, A represents the idling state of the diesel engine, and F represents the full load state (full throttle) of the diesel engine.

The injection timing control mechanism 6 includes a link mechanism 61 and a cam 65.
has.

The link mechanism 61 is the shifting means of this embodiment.

Floating lever 62 and control lever 6
Refined from 3.64.

The floating lever 62 has a pin 62a that engages with the control lever 64 at one end, and a retainer 162b that engages with the control lever 63 at the other end.
has. This floating lever 62 is connected to the shifter 5
When the lever 2 is displaced in the axial direction, it is displaced in the rotational direction about the support shaft 62c, causing the control lever 64 to reciprocate in the axial direction.

The control lever 63 has one end fixed to the other end of the shifter 52, and the other end rotatably supported by a support shaft 63a. Furthermore, a pin 63b that engages with the engagement groove 62b of the floating lever 62 is integrally provided at one end of the control lever 63.

The control lever 64 has an engagement groove (not visible in the figure) that engages with the end of the cam 65 at one end, and a pin 62 of the floating lever 62 at the other end.
It has an engagement hole 64a that engages with a.

The control lever 64 reciprocates in the axial direction when the floating lever 62 rotates about the support shaft 62c, thereby driving the cam 65 in the rotational direction.

The cam 65 is the adjustment means of this embodiment, and the cam surface 65
The tip of the stopper 42 is in contact with a, and a pin 65b that engages with the engagement groove of the control lever 64 is provided at the end. This cam 65 is connected to the control lever 64
When it reciprocates in the axial direction, it rotates along with the eccentric shaft 65c. Therefore, at the position where the desired ignition timing (desired advance characteristic) is achieved relative to the crank angle of the diesel engine,
The rotation direction of the timing control rack 4 can be changed by one degree.

The operation of the fuel injection device 1 of this embodiment will be explained based on FIGS. 1 to 4.

(2) When the rotational speed of the fuel injection pump 2 is in a low speed range, the centrifugal force of the flyweight 51 of the mechanical governor 5 increases as the rotational speed of the fuel injection pump 2, which is proportional to the rotational speed of the diesel engine, increases.

When the centrifugal force of the flyweight 51 overcomes the spring force of the spring 53 disposed outside the flyweight 51, the shifter 52 moves to the left in the figure, as shown in the graph of FIG.

Therefore, the other end of the floating lever 62 connected to the shifter 52 via the control lever 63 is displaced in the direction shown in the figure by an amount of displacement corresponding to the weight stroke S. Therefore, the floating lever 62 rotates clockwise around the support shaft 62c.

Therefore, the control lever 64 that is engaged with one end of the floating lever 62 moves to the right in the figure, so the cam 65 rotates to the left around the eccentric shaft 65c, and the tip of the stopper 42 and the cam The contact position of 65 with cam surface 65a changes.

At this time, the cam 65 does not change the position of the tip of the stopper 42 in the rotational direction at a predetermined position regardless of changes in the rotational speed of the fuel injection pump 2. Therefore, as shown in the graph of FIG. 4, the position of the timing control rack 4 in the rotational direction is also set at a predetermined position. Therefore, since the pre-stroke is set to a predetermined stroke, the position of the control sleeve 24 is set to a predetermined position corresponding to the desired advance angle characteristic.

That is, when the rotational speed of the fuel injection pump 2 is in a low speed range, the axial position of the control sleeve 24 is adjusted so that the advance angle θ advances the crank angle of the diesel engine regardless of the increase in the rotational speed of the fuel injection pump 2. Adjust mechanically. Therefore, even when the rotational speed of the fuel injection pump 2 is in a low speed range, that is, the rotational speed of the diesel engine is in a low speed range, stable ignition can be performed by advancing the fuel ignition timing with respect to the crank angle.

■When the rotational speed of the fuel injection pump 2 is in the medium speed range When the rotational speed of the fuel injection pump 2 shifts from the low speed range to the medium speed range, the weight stroke S
becomes even larger.

At this time, when the rotation speed of the fuel injection pump 2 is in the medium speed range, the cam 65 gradually rotates the tip of the stopper 42 clockwise from the low speed range, and the stopper 42 Change the position of the tip of the Then, when the tip of the stopper 42 is at a predetermined position and the rotational speed of the fuel injection pump 2 is in the medium speed range, it will remain at the predetermined position even if the rotational speed of the fuel injection pump 2 becomes faster. keep. Therefore, as shown in the graph of FIG. 4, the position of the timing control rack 4 in the rotational direction is also set to a position that delays the start timing of pumping the fuel. Therefore, the control sleeve 24 is set so that the advance angle θ is delayed from the crank angle of the diesel engine.
The axial position of is mechanically adjusted.

Fuel injection pump 2 When the rotational speed of the diesel engine is in the medium speed range, that is, when the rotational speed of the diesel engine is in the medium speed range, NOx is reduced by delaying the fuel ignition timing from the crank angle regardless of the rotational speed of the diesel engine. be able to. Therefore, it is possible to meet the demand for reducing the exhaust gas concentration of diesel engines.

m, When the rotational speed of the fuel injection pump 2 is in the high speed range When the rotational speed of the fuel injection pump 2 shifts from the low speed range to the medium speed range, the weight stroke S
becomes even larger.

At this time, the cam 65 gradually rotates the tip of the stopper 42 to the left from the medium speed range, and changes the position of the tip of the stopper 42 according to the rotational speed of the fuel injection pump 2. After the tip of the stopper 42 reaches a predetermined position, the stopper 42 maintains the predetermined position even if the rotational speed of the fuel injection pump 2 becomes higher. Therefore, as shown in the graph of FIG. 4, the position of the timing control rack 4 in the rotational direction is adjusted so that the fuel pumping start timing, that is, the advance angle θ, approaches the crank angle of the diesel engine. The position of the direction is adjusted mechanically.

That is, when the rotational speed of the fuel injection pump 2 diesel engine is in the medium speed range, that is, when the rotational speed of the diesel engine is in the medium speed range, fuel consumption can be suppressed by bringing the ignition timing of the fuel closer to the engine angle. Therefore, the demand for improving the fuel consumption rate of diesel engines can be met.

Since advance angle characteristics can also be controlled by the mechanical governor 5, which normally controls only the fuel injection amount, expensive systems such as automatic timers and microcomputers are not required, resulting in lower costs than conventional devices.

Further, it is possible to obtain desired advance angle characteristics that can satisfy the demands for diesel engines such as improved ignition performance, reduced exhaust gas concentration, and improved fuel consumption at any rotational speed of the diesel engine.

5 and 6 show a second embodiment of the invention. Fifth
The figure shows the main parts of a fuel injection device 1 for a diesel engine.

Components with the same functions as those in the first embodiment are given the same numbers.

The fitting groove 34 of the control sleeve 24 is formed upward to the left, as shown in FIG. Therefore, when the timing control rack 4 moves to the left in the figure (rightward in the figure in FIG. 5), the control sleeve 24 descends and reduces the prestroke, thereby controlling the timing at which the fuel pumping starts, that is, the diesel engine. Advance the ignition timing by adjusting the crank angle. Furthermore, when the timing control rack 4 moves to the right in the drawing (leftward in the drawing in FIG. 5), the ignition timing becomes later than the crank angle of the diesel engine.

The other end of the timing control rack 4 is provided with a pin 45 that engages with a stopper 44 .

This timing control rack 4 has a stopper 44
When the control sleeve 24 rotates about the support shaft 46, the axial position of the control sleeve 24 can be changed by reciprocating in the axial direction.

7 and 8 show a third embodiment of the invention. 7th
The figure shows a release mechanism for releasing the stopper 47 and the cam 65. 6 The same functional parts as in the first embodiment are given the same numbers.

In this embodiment, the relief lever 71 is added to that of the first embodiment.
A release mechanism 7 comprising a temperature sensing member 72 and the like is added.

The relief lever 71 rotates around a support shaft 71a.

The temperature sensing member 72 is made of thermowax, shape memory alloy, or the like, and is configured so that the cooling water temperature of the diesel engine, the environmental temperature, the fuel temperature, or the lubricating oil temperature is set to a predetermined temperature (for example, the cooling water temperature is -20°C to -30°C, the environmental temperature is Temperature is 110℃ ~
The cup-shaped tip portion moves to the right in the drawing when the oil temperature drops below -5°C and the oil temperature is between 120°C and -30°C.

For example, in the case of a device that operates based on the cooling water temperature, a bypass pipe communicating with the cooling water pipe is disposed within the mechanical governor 5, and the temperature sensing member 72 is brought into thermal contact with the bypass pipe.

The release mechanism 7 of this embodiment moves the relief lever 71 connected to the protrusion 48 of the stopper 47 from the cam surface 65a of the cam 65 using the temperature sensing member 72 when the temperature of the above-mentioned object has decreased below a predetermined temperature. Release the stopper 41.

For this reason, the timing control rack 4 can be moved as shown in the graph of FIG. 8 when the temperature of the above-mentioned components falls below a predetermined temperature with respect to the rotational speed of the fuel injection pump 2. , the advance angle θ can be made more advanced than the crank angle of the diesel engine. Therefore, it is possible to improve the ignition performance in the diesel engine when the temperature of the above-mentioned components is lower than the predetermined temperature.

In this embodiment, an all-speed mechanical governor is used as the mechanical governor, but a high-low speed mechanical governor may also be used.

In this embodiment, both the fuel injection amount and the fuel pumping start timing are controlled by the mechanical governor, but only the fuel pumping start timing may be controlled by the mechanical governor.

In this embodiment, the drive mi from the camshaft and tappet is
However, the drive mechanism may also be constructed using only the camshaft.

[Brief explanation of drawings]

1 to 4 show a first embodiment of the invention. 1st
The figure is a perspective view showing the main parts of a fuel injection device for a diesel engine, Figure 2 is a graph showing the relationship between the rotational speed of the fuel injection pump and the weight stroke, and Figure 3 is a graph showing the relationship between the rotational speed of the fuel injection pump and the injection amount control. FIG. 4 is a graph showing the relationship between the rotational speed of the fuel injection pump and the position and advance angle of the timing control rack. 5 and 6 show a second embodiment of the invention. Fifth
The figure is a perspective view showing the main parts of the fuel injection device for a diesel engine, and FIG. 6 is a front view of the control sleeve. 7 and 8 show a third embodiment of the invention. 7th
This figure is a perspective view showing the release mechanism, and FIG. 8 is a graph showing the relationship between the rotational speed of the fuel injection pump and the position and advance angle of the timing control rack. In the diagram 1...Fuel injection device for diesel engine 2...
Fuel injection pump 4... Timing control rack (control means) 5... Mechanical governor 23.
... Plunger lightweight 24 ... Control sleeve 51 ... Flow 1 ... Link mechanism (transfer means) 5 ... Cam (adjustment means)

Claims (1)

[Claims] 1) (a) A plunger that is driven reciprocally in the axial direction by an internal combustion engine and pumps fuel; a sleeve that changes the pumping start timing; and a fuel injection pump that is connected to the sleeve and has a control means that changes the axial position of the sleeve in response to the change in position; (b) the rotational speed of the internal combustion engine; a flyweight whose centrifugal force changes in response to a change in the flyweight; a displacement means connected to the flyweight and which shifts in response to a change in the centrifugal force of the flyweight; and a displacement means interposed between the control means and the displacement means. and adjusting means for connecting the control means and the shifting means, and adjusting the position of the control means with respect to the shift of the shifting means to a position corresponding to a desired ignition timing with respect to a crank angle of the internal combustion engine. A fuel injection device for an internal combustion engine, comprising a mechanical governor.