JP2521716Y2 - Pre-stroke adjusting device for fuel injection pump of diesel engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Field of Industrial Application >> The present invention relates to a device for automatically adjusting the pre-stroke of a fuel injection pump in a diesel engine according to the operating state of the engine.

<< Basic Basic Structure >> Some prestroke adjusting devices of this type of fuel injection pump have a basic structure as follows. For example, as shown in FIGS. 1 to 4, a control sleeve 18, a control rod 19, and an actuator 20 for adjusting the pre-stroke of the plunger 7 are attached to the fuel injection pump 5 of the diesel engine 1. , Is fitted to the outer peripheral surface of the plunger 7 so as to be able to reciprocate in the axial direction, and a sleeve input portion 22 for moving operation is formed at the eccentric position. The rod input portion 19a of the control rod 19 is interlockingly connected to the output portion 20a of the actuator 20 while being arranged in a direction substantially orthogonal to the pump case 23 and supported so as to be able to swing back and forth around the rod axis A with respect to the pump case 23. The rod output section 19b provided eccentrically to the control rod 19 is connected to the sleeve input section 22 of the control sleeve 18. Connect the control rod 1 with the output 20a of the actuator 20
The control sleeve 18 is reciprocated by the rod output portion 19b by swinging the rod 9 around the rod axis A, and the pre-stroke of the plunger 7 is adjusted.

In the above basic structure, the rod arm length L of the rod output portion 19b is determined as follows in FIG. 4 in order to achieve the miniaturization of the fuel injection pump 5.

To reduce the size of the fuel injection pump 5, a rod output section
It is necessary to shorten the rod arm length L of 19b to bring the rod axis A closer to the control sleeve 18. However, as the rod arm length L is shortened, there arises a problem that the durability of the fuel injection pump 5 decreases. .

That is, as the rod arm length L becomes shorter, the rod swing angle D required to secure the predetermined pre-stroke adjustment width S becomes larger. Along with this, the rod output section 19b
When the plunger 7 is operated at the maximum swing angle, the cantilever length B of the control sleeve 18 supported by the rod output portion 19b is increased. Therefore, the durability of the fuel injection pump 5 is reduced.

For this reason, the shortest dimension of the rod arm length L has been determined as follows.

First, the allowable pre-stroke adjustment width Sa is determined by providing the manufacturing error absorption widths U and V in both outer regions of the reference pre-stroke adjustment width So determined by the design conditions. Next, the cantilever length Ba that is allowable for preventing the control sleeve 18 from being twisted is determined. Then, the shortest rod arm length L is determined by determining the allowable rod swing angle Da so as not to exceed the allowable cantilever length Ba while securing the allowable prestroke adjustment width Sa.

<< Conventional technology >> As a method of adjusting the pre-stroke of a fuel injection pump,
Widely adopted, like the premise structure described above,
The control sleeve, which is swingably mounted on the plunger, is linked to the control rod, and a pre-stroke control actuator is provided for driving the control rod to rotate.The control sleeve is moved up and down via the actuator to move the plunger up and down. (Hereinafter referred to as Conventional Example 1).

Then, the actuator is driven from the data of the engine speed and the load, and the control sleeve is moved up and down to adjust the pre-stroke of the plunger of the fuel injection pump. In this case, the control range of the fuel injection timing of the fuel injection pump is generally adjusted by the pump unit alone before the fuel injection pump is attached to the diesel engine.

However, adjustment of the pump unit alone is, of course, necessary to improve the accuracy of the fuel injection pump itself,
Inspection of the fuel injection control range by simply attaching the fuel injection pump to the engine may not be able to obtain the required engine characteristics due to engine individual differences (errors in mounting the fuel injection pump to the engine, etc.). is there.

With respect to the adjustment of the mounting position of the fuel injection pump to the engine, a device disclosed in Japanese Utility Model Laid-Open No. 63-140152 is disclosed. This device has the same configuration as that of the conventional example 1 except that a position sensor for detecting the rotation angle of the control rod is provided and the following features (1) to (3) are provided.

(1) The rotation angle of the control rod is regulated by a stopper, and the lower limit of the pre-streak is regulated by the stopper.

(2) The upper end surface of the control sleeve is the valve housing (the control sleeve storage space for the plunger)
The upper limit of the pre-stroke control range is regulated by contacting the lower end of the stroke.

(3) Prestreak between them is controlled based on the upper and lower limits of the control range determined in (1) and (2).

According to the device disclosed in Japanese Utility Model Application Laid-Open No. 63-140152, one control limit of the pre-stroke control determined by the assembled state of the actuator and the other control limit are detected in advance, and the upper limit and the lower limit are used to detect the limit. It is described that since the pre-stroke is controlled, it is not necessary to adjust the mounting position.

<Problem to be Solved by the Invention> However, in the device disclosed in Japanese Utility Model Application Laid-Open No. 63-140152, the pre-stroke is controlled by the lower end of the valve housing, which is the fixed upper limit, and the stopper, which is also the fixed lower limit. Therefore, in the process of adjusting the fuel injection pump 5 by performing a performance test before shipping, there is a problem that the pre-stroke cannot be mechanically limited in accordance with the characteristics of the actual diesel engine. In other words, the most advanced and most retarded positions of the pre-stroke should be determined as accurately as possible according to the actual engine characteristics in order to greatly affect the engine performance. In this case, the upper limit and the lower limit are both fixed and cannot be changed, so that the range of adjustment of the fuel injection pump 5 is limited. In particular, it is preferable that the adjustable range of the diesel engine is wide because the operating performance such as the output and the fuel efficiency varies greatly due to the machining error and the assembly error at the time of manufacturing.

In addition, the operating characteristics of diesel engines often differ greatly depending on the type of work, and the amount of pre-stroke is adjusted at the stage of mounting the fuel injection pump on the engine according to the application of the diesel engine used and individual engine characteristics If it could be done, it was extremely convenient in practice.

Further, in the device disclosed in Japanese Utility Model Application Laid-Open No. 63-140152, the following problem arises in that the fuel injection pump is reduced in size as in the above-described premise structure. That is, in the device of Japanese Utility Model Application Laid-Open No. 63-140152, the maximum pre-stroke position is regulated by the upper end surface of the control sleeve abutting against the lower end of the valve housing. In such a case, the control sleeve is strongly pressed against the lower end of the valve housing, and the control sleeve is abnormally worn.

《Purpose of the invention》 The purpose of the invention is to make fine adjustments to the fuel injection timing even after the fuel injection pump is mounted on the engine, and to stabilize the performance of each engine during mass production in view of the above-mentioned problems of the prior art. It is an object of the present invention to provide a pre-stroke adjusting device for a fuel injection pump of a diesel engine that can be converted into a diesel engine.

Another object of the present invention is to achieve downsizing of the fuel injection pump having the above-described premise structure, to prevent abnormal wear on the control sleeve even during a disturbance, etc., to ensure the durability of the fuel injection pump, It is an object of the present invention to provide a pre-stroke adjusting device for a fuel injection pump of a diesel engine, which can enhance engine reliability.

<< Means for Solving the Problems >> As shown in FIGS. 1 to 4, for example, the pre-stroke adjusting device of the present invention controls the fuel injection pump 5 of the diesel engine 1 to adjust the pre-stroke of the plunger 7. A sleeve 18, a control rod 19, and an actuator 20 are additionally provided. The control sleeve 18 is fitted on the outer peripheral surface of the plunger 7 so as to be reciprocally movable in the axial direction, and a movement operation sleeve input section 22 is provided at the eccentric position. The control rod 19 is arranged in a direction substantially orthogonal to the plunger 7 on a different plane, and is supported by the pump case 23 so as to be reciprocally swingable around the rod axis A. The rod input section 19a of the rod 19 is connected to the output section 20a of the actuator 20 in an interlocking manner, and is eccentric to the control rod 19. The provided rod output section 19b is connected to the sleeve input section 22 of the control sleeve 18, and the control rod 1 is connected to the output section 20a of the actuator 20.
By rotating the control sleeve 18 around the rod axis A, the control sleeve 18 is reciprocated by the rod output portion 19b to adjust the pre-stroke of the plunger 7 so as to adjust the pre-stroke of the diesel engine. In the stroke adjusting device, movable restrictors 27, 28 are provided in a pre-stroke adjusting force transmission system T from the output portion 20a of the actuator 20 to the rod input portion 19a of the control rod 19, and one movable restrictor 27 is provided. However, within the swing allowable range Sa where the control sleeve 18 is not twisted, the allowable minimum press stroke position Xa of the control sleeve 18 is set, and the other movable mold 28 is set within the swing allowable range Sa. , And sets the allowable maximum pre-stroking position Ya.

<< Operation >> The present invention operates as follows.

(B) Miniaturization of the fuel injection pump The arm length L of the rod output portion 19b is the same as that described in the basic structure described above, while ensuring the allowable pre-stroke adjustment width Sa and the allowable cantilever length Ba. The shortest dimension is set by determining the allowable rod swing angle Da so as not to exceed. As a result, the fuel injection pump 5 can be made small by bringing the rod axis A of the control rod 19 closer to the control sleeve 18.

(B) The most advanced and most retarded pre-strokes can be set according to each engine. The most advanced and most retarded pre-stroke settings have a significant effect on engine performance, so the actual engine characteristics should be as large as possible. According to the present invention, it is preferable to determine the position accurately according to the movable stroke of the movable restrictor in the prestroke adjusting force transmission system T from the output portion 20a of the actuator 20 to the rod input portion 19a of the control rod 19. Since the adjusters 27 and 28 are provided, the adjuster can move the movable restrictor from the outside of the engine when the engine is shipped, so that the most advanced angle and the most retarded angle of the prestroke can be set. Therefore, when there are individual differences in driving performance such as output and fuel efficiency due to machining errors and assembly errors during the production of diesel engines,
The most advanced and most retarded positions of the pre-stroke can be forcibly (mechanically) determined according to the individual differences, and the engine characteristics can be fine-tuned according to the needs of the engine. become.

(C) Ensuring reliability at the time of disturbance, etc. When the calculated pre-stroke adjustment width Sr is out of the allowable pre-stroke adjustment width Sa due to disturbance or abnormality during operation of the diesel engine,
Each of the movable restrictors 27 and 28 operates as follows.

If the required minimum pre-stroke position Xr is smaller than the allowable minimum pre-stroke position Xa, one of the movable states that the actuator 20 operates the control sleeve 18 beyond the allowable minimum pre-stroke position Xa in accordance with the operation state detection value. Blocked by the mold restrictor 27. When the required maximum pre-stroke position Yr is larger than the allowable maximum pre-stroke position Ya, the actuator 20 operates the control sleeve 18 beyond the allowable maximum pre-stroke position Ya in accordance with the detected operation state. Is stopped by the movable restrictor 28.

As described above, since the control sleeve 18 is reciprocated within the allowable pre-stroke adjustment width Sa, the cantilever length B of the rod output portion 19b can be kept within the area of the allowable cantilever length Ba. As a result, abnormal wear of the control sleeve 18 due to reciprocation of the plunger 7 at the time of disturbance or the like can be prevented, the durability of the fuel injection pump 5 can be secured, and the reliability of the engine can be improved.

<< Example >> Hereinafter, an example of the present invention will be described with reference to the drawings.

First Embodiment FIGS. 1 to 5 show a first embodiment.

1 is a cross-sectional view taken along the line II of FIG. 2, FIG. 2 is a vertical cross-sectional view of a fuel injection pump mounting portion of the diesel engine, FIG. 3 is a view taken along the line III-III of FIG. FIG. 4 shows the first
FIG. 5 is an enlarged schematic diagram of a main part of the figure, and FIG. 5 is a control block diagram.

The fuel injection pump unit 3 attached to the engine case 2 of the diesel engine 1 includes three fuel injection pumps 5
Are juxtaposed. Each fuel injection pump 5 is of a known type, and is configured to reciprocate a plunger 7 inserted into each pump body 6 in the vertical direction via a roller 10 by a driving cam 9 of a pump driving cam shaft 8. The adjustment of the fuel injection amount is performed by rotating the plunger 7 about the axis with the governor lever 12 through the rack pin 13, the fuel injection amount adjustment rack 14, and the rotary cylinder 15 in this order. Note that a start spring 16 is provided between the upper end of the governor lever 12 and the engine case 2. The fuel injection pump 5 is configured to have a variable pre-stroke. That is, in order to adjust the pre-stroke of the plunger 7,
A control sleeve 18, a control rod 19, and an actuator 20 are provided.

The control sleeve 18 is fitted on the outer peripheral surface of the plunger 7 so as to be able to reciprocate in the axial direction, and has a moving operation sleeve input portion 22 formed at an eccentric position thereof. Further, the control rod 19 is arranged in a direction substantially orthogonal to a plane different from the plunger 7, and is supported by the pump case 23 via the pivot tube 24 so as to be able to swing back and forth around the rod axis A. A rod input section 19a of the control rod 19 is linked to an output section 20a of the actuator 20 via an operation lever 25. Further, a rod output portion 19b provided eccentrically to the control rod 19 is connected to the sleeve input portion 22 of the control sleeve 18.
Connected to.

The actuator 20 comprises a linear stepping motor, and as shown in FIG.
Engine speed sensor 51, cooling water temperature sensor 52,
It is linked to the load sensor 53. And the controller
50 adjusts and operates the actuator 20 based on the engine operating state detected values from the sensors 51, 52, 53. Then, by swinging the control rod 19 around the rod axis A through the operation lever 25 at the output part 20a, the rod output part 19b reciprocates the control sleeve 18 in the vertical direction, and the plunger 7 The pre-stroke is adjusted.

In the above configuration, in the pre-stroke adjustment transmission system T from the output section 20a of the actuator 20 to the rod input section 19a of the control rod 19, the operation lever 25, which is a constituent member thereof, has Movable restrictor for setting pre-stroke position Xa
27, and a movable restriction member 28 for setting the allowable maximum pre-stroke position Ya. These two movable type restrictors 27 and 28
Is composed of a bolt screwed into a placket 30 protruding from the lower surface of the pump case 23 so as to be able to advance and retreat.
It is located on the top and bottom sides of the 25 tips.

Therefore, the bolts can be advanced and retracted to adjust the most advanced angle and the most retarded angle in accordance with individual differences in the operating performance of each engine, so that the most advanced position and the most advanced angle are extremely important for the performance of the engine. The angular position can be determined accurately.

Also, after adjusting the most advanced position and the most retarded position with the movable restrictor, a prestroke value exceeding the most advanced position and the most retarded position was output from the controller 50 due to disturbance during engine operation or the like. Or actuator
Even if an error factor such as a displacement occurs in the pre-stroke adjusting force transmission system T from 20 to the input portion 19a of the control rod 19, the drive may be performed beyond the most advanced position and the most retarded position. Since the plunger 7 is reciprocated, the control sleeve 18 is twisted and abnormally worn, and the fuel injection pump 5 is not damaged.

The function of protecting the fuel injection pump will be further described with reference to FIG.

By moving the two movable restrictors 27 and 28 forward and backward, the fuel injection pump 5 can be tested according to the performance test of each engine before shipment.
It is assumed that the most advanced position and the most retarded position are adjusted. And
When adjusting the control sleeve 18 via the control rod 19 by adjusting the actuator 20 based on the detected operating state values such as engine speed, cooling water temperature, engine load, etc., due to abnormal factors such as disturbance, Incorrect required prestroke adjustment range
It is assumed that Sr has exceeded the area of the allowable pre-stroke adjustment width Sa.

Here, if the configuration is such that the control sleeve 18 is simply adjusted and operated in accordance with the operating state detection value such as the engine speed without providing the two movable restriction members 27 and 28, the following problem occurs. That is, when the rod output section 19b is operated to the required minimum pre-stroke position Xr or the required maximum pre-stroke position Yr, the rod output section 19b is operated up to a region exceeding the allowable rod swing angle Da, so that the maximum cantilever length Bm Is the allowable cantilever length Ba
Beyond. As a result, the reciprocating drive of the plunger 7 causes the control sleeve 18 to bend and abnormally wear, and the durability of the fuel injection pump 5 is significantly reduced.

According to the present invention, even in such a case, the operation of the movable restriction members 27 and 28 prevents the fuel injection pump 5 from being operated to a region beyond the allowable rod swing angle Da, and thus can protect the fuel injection pump 5. Therefore, according to the present invention, it is possible to secure the reliability of driving the engine in the event of an abnormal factor such as a disturbance while achieving downsizing of the pump.

In the above embodiment, the adjustment of the fuel injection amount of the fuel injection pump 5 may be performed by using an electronic governor instead of the mechanical governor shown in the above embodiment.

(Second Embodiment) FIGS. 6 and 7 show a second embodiment. FIG. 6 is a diagram corresponding to FIG. 3, and FIG. 7 is a sectional view taken along line VII-VII of FIG.

In this case, the movable restricting tool 27 for setting the allowable minimum pre-stroke position Xa is screwed to the mounting flange 32 of the pump case 23 so as to be adjustable in the vertical direction.

In addition, the movable restriction member 28 for setting the allowable maximum pre-stroke position Ya is provided with a tension adjusting bolt of the start spring 16.
A flexible rod member 34 is mounted in the cylindrical hole 33 so as to be able to advance and retreat. The lower end position of the operation lever 25 is set by the rod tip 34a by operating the rod member 34 with the adjusting screw 35.

(Another embodiment) FIG. 8 is a diagram for explaining the operation of the means for calibrating the injection timing of the fuel injection pump.

Generally, non-feedback type actuators are often used for adjusting the injection timing and the pre-stroke. In this type of actuator, even if the adjustment position of the injection timing or the adjustment position of the pre-stroke (hereinafter referred to as an example of the adjustment position of the injection timing) is calibrated to the starting advance position before starting the diesel engine, If the position shift occurs due to some disturbance during the operation, there is a problem that the adjustment operation is performed with the position shift over the entire period during the operation. The present embodiment is intended to prevent the above-mentioned adverse effects with a simple configuration. The basic structure for adjusting the injection timing is as shown in FIG. That is, the controller 50 controls the adjustment position of the injection timing of the fuel injection pump 5 via the actuator 20 based on the detected values of the rotation speed sensor 51, the cooling water temperature sensor 52, and the load sensor 53. Hereinafter, description will be made with reference to FIG.

FIGS. 8A to 8C respectively show the relationship between the engine speed N and the injection timing そ れ ぞ れ. Here, the idle speed N ₀ is 850 rpm, and the rated speed N ₁ is 2600 rp.
m.

(A) shows a case where the cooling water temperature and the load change according to the engine operating state. In this case, as in the conventional case, when the engine is started or stopped, the injection timing Θ is calibrated to the start advanced position, and when the engine speed N is equal to or less than the idle speed N ₀ , the injection timing Θ is adjusted to that rotation speed. Switch to the warm-up advance position according to the number (see the dashed line diagram).
Further, the engine rotational speed N is in the region of the rated speed N ₁ from the idling speed N _0, the optimum injection timing Θ which is predetermined based on the detection value of the engine speed, coolant temperature, load
(Hatched area).

(B) shows a state in which the load has changed to 0/4 while the cooling water temperature is kept in a steady temperature range (for example, a predetermined range around 80 ° C.). In this case, where even switches the injection timing Θ to harm is unlikely most retarded position at the time of no load (dashed line view of the engine rotational speed N is the rated speed N ₁ from idle speed N ₀ Perform calibration.

(C) shows that the engine speed N is equal to the set speed N _{2 in} a high-load (for example, 2/4 load or more) operating state while the cooling water temperature is maintained in a steady-state temperature region (a region around 80 ° C.). shows the case of reduced (here 2200 rpm) is equal to or greater than, or idle speed N ₀ or less for some reason. Then, when the engine speed N changes to that range, the injection timing Θ is switched to the most advanced position where actual harm is unlikely to occur under a high load (see the dashed line diagram), and calibration is performed. Incidentally, when the engine speed N from idle speed N ₀ in the rated rotational speed N ₁ in the region controls in the (a) diagram in the case as well as the optimum injection timing theta (hatched portion).

Thus, during operation of the diesel engine,
Although the controller can calibrate the adjustment position of the injection timing て based on the detected values of the engine speed, the cooling water temperature, and the load, the calibration does not require a dedicated calibration means, so a simple configuration is used. Optimal control can be achieved.

<< Effects of the Invention >> As described above in detail, according to the present invention, the following specific effects can be obtained from the configuration and operation described above.

(B) Miniaturization of the fuel pump By setting the rod arm length of the rod output part of the control rod to the shortest dimension, the fuel injection pump can be made small.

(B) The maximum advance and the minimum retard of the pre-stroke can be set according to each engine. The upper and lower limits can be set by moving the movable restrictor. When there are individual differences in driving performance such as output and fuel efficiency due to assembly errors or assembly errors, the position of the most advanced pre-stroke and the most retarded angle of the pre-stroke, which is extremely important in engine characteristics, is Can be determined mechanically according to the characteristics of the device, and the range of adjustment can be widened. Further, the characteristics of the engine can be finely adjusted even after the fuel injection pump is mounted on the engine in the form of use of the engine.

(C) Ensuring reliability in the event of a disturbance, etc.
Even if there is a risk of driving exceeding the allowable pre-stroke, the control sleeve moves the control sleeve within the range of the allowable pre-stroke adjustment width between the allowable minimum pre-stroke position and the allowable maximum pre-stroke position. , The control sleeve can be prevented from being twisted and abnormally worn by the reciprocating drive of the plunger, and the reliability of the engine can be secured.

[Brief description of the drawings]

1 to 8 show an embodiment of the present invention. 1 to 5 show a first embodiment, FIG. 1 is a sectional view taken along line II of FIG. 2, FIG. 2 is a longitudinal sectional view of a fuel injection pump mounting portion of a diesel engine, 3 is a view taken along the line III-III of FIG. 2, FIG. 4 is an enlarged schematic view of a main part of FIG. 1, and FIG. 5 is a control block diagram. 6 and 7 show the second embodiment, FIG. 6 is a view corresponding to FIG. 3, and FIG. 7 is a sectional view taken along line VII-VII of FIG. FIG. 8 shows another embodiment and is an operation explanatory diagram of the injection timing calibration means of the fuel injection pump. 1 ... diesel engine, 5 ... fuel injection pump, 7
…… Plunger, 18 …… Control sleeve, 19 ……
Control rod, 19a …… Rod input section, 19b …… Rod output section, 20 …… Actuator, 20a …… Output section, 2
2 ... Sleeve input section, 23 ... Pump case, 27/28 ...
... Movable restrictor, A ... Rod axis, T ... Prestroke adjusting force transmission system, Xa ... Allowable minimum prestroke position, Ya ... Allowable maximum prestroke position.

Claims (1)

(57) [Scope of request for utility model registration] A fuel injection pump (5) of a diesel engine (1) is provided with a control sleeve (18), a control rod (19) and an actuator (20) for adjusting a pre-stroke of a plunger (7). The control sleeve (18) is fitted on the outer peripheral surface of the plunger (7) so as to be able to reciprocate in the axial direction and has a sleeve input part (22) for movement operation at an eccentric position thereof. 19) is disposed in a direction substantially orthogonal to the plunger (7) on a different plane, and is supported by the pump case (23) so as to be reciprocally swingable around the rod axis (A). The rod input section (19a) of the rod (19) is interlocked with the output section (20a) of the actuator (20), and the rod output section (19a) is provided eccentrically to the control rod (19). The part (19b) is connected to the sleeve input part (22) of the control sleeve (18), and the control rod (19) is swung around the rod axis (A) by the output part (20a) of the actuator (20). Accordingly, in the pre-stroke adjusting device of the fuel injection pump for the diesel engine, the control sleeve (18) is reciprocated by the rod output portion (19b) to adjust the pre-stroke of the plunger (7). Movable restrictors (27) and (28) are provided in the prestroke adjusting force transmission system (T) from the output section (20a) of (20) to the rod input section (19a) of the control rod (19), When one of the movable restrictors (27) is in the swing allowable range (Sa) where the control sleeve (18) is not twisted, the control sleeve (18)
And the other movable die (28) sets the allowable maximum pre-stroke position (Ya) within the swing allowable range (Sa). A pre-stroke adjusting device for a fuel injection pump of a diesel engine, characterized in that: