JPS6185572A - Injection timing adjusting method of fuel injection pump - Google Patents

Abstract

PURPOSE:To fine-adjust and match the injection timing of a fuel injection pump quickly, easily, and reliably by connecting the fuel feed outlet downstream a discharge valve to a pressure air source via an air manometer and feeding the pressure air to a pump chamber. CONSTITUTION:The fuel feed outlet 22 downstream a discharge valve 16 is connected to a pressure air source 84 via an air manometer 78, and the pressure air is fed to a pump chamber 14. During a normal operation, a seal plug 88 is removed, and a control sleeve 38 is displaced upward or downward via an injection timing control member 44. The instant when a control groove 58 is opened or closed by the control sleeve 38 is detected by the manometer 78, and the control member 44 is fixed in this position. Accordingly, the injection timing can be fine-adjusted and matched quickly, easily, and reliably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for adjusting the injection timing of a fuel injection pump for an internal combustion engine, particularly a diesel engine.

In a conventional in-line fuel injection pump for a diesel engine, a barrel is housed inside the pump housing, and a pump chamber having a spring-loaded discharge valve is provided within the barrel, and one end faces the pump chamber and the other end faces the pump chamber. The plunger is operatively connected to a cam driven by the engine, and a control sleeve is fitted on the outer periphery of the plunger so as to be slidable in the axial direction, and the control sleeve is constantly supplied with fuel by a feed pump. For example, a device arranged in a fuel chamber is disclosed in the specification of Patent Application No. 37541 of 1974 (filed on March 29, 1978). In this known device, a control groove is provided on the control sleeve and is inclined with respect to the plunger axis, and one end opens into the pump chamber and the other end opens near the lower end surface of the control sleeve to form a control hole. A channel is provided in the sylanger, and the plunger is rotated around its axis to change the relative position of the control hole with respect to the control groove, thereby adjusting the fuel injection amount and freely rotating the plunger. The rotation of an eccentric pin on a supported camshaft displaces the control sleeve in the axial direction of the plunger to adjust the injection timing. However, each of the seven rings of the multi-cylinder ennon is equipped individually.
Due to manufacturing errors and assembly errors of each part during manufacturing, the fuel injection timing of the fuel injection pumps of each ring usually lacks uniformity, so the fuel injection timing of each 27 Zo is made as uniform as possible before being installed on the Ennon. It is necessary to align with For this purpose, conventionally, fuel was actually flowed through each of the seven-ring injection pumps to check the injection timing, and if there was a discrepancy, the seal plug in the housing was removed and a tool was inserted through the adjustment opening to connect the control sleeve. After finely adjusting the relative position of the plunger in the axial direction, the seal plug was reinstalled, and the method of checking injection timing by flowing fuel was repeated. Therefore, as the number of cylinders increases, the task of adjusting the injection timing becomes extremely troublesome, resulting in a problem that requires a great deal of effort and cost.

The present invention was devised in view of the above circumstances, and includes a barrel housed in a housing, a syringe inserted in the barrel so as to be slidable in two axial directions, and a syringe mounted in the barrel and loaded with a spring. a discharge valve; a pump chamber bounded within the barrel by the discharge valve and one end surface of the plunger; a fuel chamber within the barrel formed surrounding the plunger; A fitted control sleeve, an oil passage in the granger whose one end opens into the pump chamber, an outer circumferential surface of the 70 lantern and a control sleeve for communicating or disconnecting the pump chamber and the fuel chamber via the oil passage. a control groove provided on one side of the plunger at an angle with respect to the axis of the plunger; a control hole provided on the other side of the outer peripheral surface of the plunger and the control sleeve that cooperates with the control groove; and an injection for rotating the control sleeve around the axis of the plunger. and a quantity control member disposed on a control shaft substantially perpendicular to the plunger axis and engaged with the control sleeve to adjust the relative position of the sleeve with respect to the plunger in the plunger axis direction to adjust fuel injection timing. and an injection timing control member configured to be fixed on the control shaft such that the injection timing control member can be adjusted around the axis of the control shaft, wherein the discharge valve is removed and the injection timing control member is Connect the fuel outlet downstream of the valve to a pressurized air source via an air manometer to forcefully feed pressurized air to the pump chamber, and remove the seal plug that normally blocks the adjustment opening in the housing. The control sleeve is displaced upward or downward via the injection timing control member, the air manometer detects the moment when the control groove is opened or closed by the control sleeve, and the injection control member is moved at that position. The gist of this invention is a method for adjusting the injection timing of a fuel injection pump, which is characterized by fixing the injection timing on the control shaft.

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. First, an example of the structure of a fuel injection pump to be adjusted by the method of the present invention will be described. Reference numeral 10 is a housing of the fuel injection pump, 12 is a barrel that is removably fitted into the upper end of the housing, and 14 is a housing of the fuel injection pump. A pump chamber 16 is formed in the four barrels 12, and a fuel discharge valve 22 is housed in a discharge valve holder 18 screwed into the upper end of the barrel and is preloaded by a spring 20 to close off the pump chamber 14. A discharge passage provided in the discharge valve holder 18 and communicating with a fuel injection nozzle via a fuel injection pipe (not shown); 24 is a plunger slidably fitted into the housing 10 via the barrel 12; , its upper end surface 24a faces the pump chamber 14, and its lower end portion 24b contacts the cam 30 via a shaft 26 and a roller 28. 32 is a camshaft driven by an unillustrated ennon; 34 is a spring that always presses the R throat 26 against the cam 30 side;
A fuel chamber 36 is formed surrounding the plunger 24, and is constantly supplied with fuel by a feed pump (not shown) while the engine is operating. 38 is a cylindrical fuel control sleeve fitted on the outer circumference of the plunger 24 in the fuel chamber 36 so that it can freely slide in the axial direction and rotate freely; 40 is fitted on the outer circumference of the plunger 24 on the outer circumference of the sleeve 38; 42 is an injection timing control shaft whose axis is included in a plane perpendicular to the axis of the plunger 24; 44 is a bolt or It is a movable injection timing control member that is coaxially fixed by tightening a screw 46, and has an arm 48 projecting from the control member, and a spherical portion 50 at the tip thereof fitted into the guide groove 40. . 52 is a gear provided on the outer peripheral surface of the control sleeve 38 on the side opposite to the guide groove 40 over approximately a semicircumference; 54 is a control rack that meshes with the gear 52; and 56 is one end of which is connected to the pump chamber. 14, and the other end is connected to the control sleeve 3.
An oil passage in the plunger that communicates with a control groove 58 cut in the outer circumferential surface of the plunger in contact with the inner circumferential surface of No. It has a λ (lambda) shape as a whole. 60 is a control hole bored in the radial direction on the control sleeve 38 and cooperates with the control groove 58; 62 is a plunger guide fitted in the lower end portion of the plunger 24; The square part 2 on the corresponding plano gloss 24
4c, and as a result, the plunger 24 can be freely displaced in the axial direction with respect to the barrel 12 and the guide 62, but the plunger 24 is fitted around the axis with respect to the plunger guide 62.
It is not possible to rotate relative to the Also, as shown in detail in FIG. 4, the upper end 7 of the plunger guide 62
A protrusion 68 having an engagement groove 64 extending in the axial direction is provided on the outer peripheral portion of the runno.

On the other hand, on the wall facing the protrusion 68 of the housing IO,
An adjusting member 72 equipped with an eccentric pin 70 that fits into the retaining groove 66 is rotatably fitted, and a screw portion 74 of the adjusting member 72 that protrudes outward from the door 6 is attached. It is designed to be screwed together.

An outline of the operation of the injection pump described above will be explained below.

First, when each member of the pump is in the illustrated position, the control hole 6
0 and the control groove 58 do not communicate with each other, and the lower end of the control groove 58 protrudes downward from the lower end surface of the control sleeve 38 and opens into the fuel chamber 36, so the pump chamber 14 and the fuel chamber 36 communicate with each other. . Now, from this state, the cam shaft 32 is rotated, and the cam 3
When the syringer 24 is pushed upwardly by the roller 28, the lower end of the control groove 58 is closed by the control sleeve 38, and the communication between the inclined part of the control groove and the control hole 60 is cut off. Therefore, communication between the pump chamber I4 and the fuel chamber 36 is cut off. Therefore Granja 24
The increase in pressure pressurizes the fuel in the pump chamber, and when the pressure exceeds a set value, the discharge valve 16 is opened and fuel is supplied from the discharge passage 22 to the injection nozzle of the ennon. When the syringer 24 further rises and the inclined groove portion of the control groove 58 communicates with the control hole 60 of the control sleeve 38, the pump chamber 14 communicates with the fuel chamber 36 again, and fuel injection ends. Thereafter, the upper end of the axial portion of the control groove 58 projects upward from the upper end surface of the control sleeve 38 to directly communicate the pump chamber 14 and the fuel chamber 36, thereby reliably preventing two-stage injection. Next, the control rack 54
By moving the control sleeve 38 in its axial direction, rotating the control sleeve 38 around the axis of the plunger 24, and changing the relative position between the control hole 60 and the control groove 58, the amount of fuel supplied can be increased or decreased. . During normal operation after completion of injection timing adjustment work, which will be described later, the control shaft 42 is rotated around its axis and the control sleeve 3 is rotated via the control arm 48.
8 in the axial direction of the plunger 24, the relative position of the control hole 60 and the control groove 58 in the cam lift direction changes, that is, the injection timing is adjusted. Note that, as is well known in the art, the control rack 54 and the control shaft 42 are controlled manually or appropriately by an engine control device (not shown) (in the case of a vehicle, an accelerator pedal, a governor, a timer, etc.). is driven by an actuator.

Now, in the fuel injection pump as described above, after its manufacturing and assembly is completed, several seven
It is necessary to align and match the fuel injection timing of the ring injection pump. According to the present invention, the injection timing is adjusted as follows.

(1) First, remove the discharge valve holder 18, remove the discharge valve 16 and spring 20, and then attach it to the barrel 12 again.
An air manometer 78 is connected to the open end of the discharge passage 22 by a fitting 80.

The air manometer 78 is also connected to a compressed air source 84 via a pressure reducing valve 82 .

(2) On the other hand, remove the 7-hole plug 88 screwed into the adjustment opening 86 formed in the wall portion of the housing 10 facing the injection timing control member 44 to open the opening.

(3) When the pressure reducing valve 82 is opened in the above state, the regulated compressed air passes through the air manometer 78, passes through the discharge passage 22, the pump chamber 14, the oil passage 56, the control groove 58, and flows into the fuel chamber 36, and then leaks into the outside air. (Note that the control sleeve 38 is now in the position shown in FIGS. 1 and 3.) In this case, the seed 90 of the air manometer 78 is in a floating position as shown due to the air flow.

(4) Then, insert a suitable tool through the adjustment opening 86 and adjust the arm 4B of the injection timing control member 44 to the position shown in FIGS.
Slight clockwise rotation in the figure moves the control sleeve 38 downward relative to the syringe 24. The moment the control sleeve 38 descends and covers the lower edge of the control groove 58, the flow of compressed air stops. This cessation of the air flow can be accurately confirmed by the falling of the seed 90 of the air manometer 78. This position is nothing but the injection start position. The bolt or screw 46 is then tightened at this location to secure the control member 44 onto the control shaft 42.

Therefore, the injection timing of the injection pump for each cylinder can be adjusted very easily and quickly with respect to the appropriately set crank angle position (the axial position of the cam 30 and therefore the syringer 24).

After examining this by flowing fuel in the conventional manner, the seal,
Compared to the case where the flag 88 is removed, the injection timing control member 44 is finely adjusted, and the fuel is flowed again to check the result several times, the time required for adjustment is reduced to less than a fraction of the cost, and the cost is reduced. It is clear that there are corresponding savings in Note that, contrary to the above method, the control sleeve 38 is first closed off, and the control sleeve 38 is gradually raised by .zeta., and the lower end of the control groove 58 is The gauge at which the compressed air begins to flow when the compressed air is opened can also be recognized as G1° by the floating of the seed 90 of the air manometer 78. Further, in the above embodiment, the control groove 58 is provided on the syringe 24, and the control sleeve 3
8 is provided with a control hole 60 that cooperates with the plunger 24. Similarly to the known device, a control groove is provided on the control sleeve 38 side and is inclined with respect to the axis of the plunger.
The present invention can be similarly applied to a device configured to open a control hole communicating with the oil passage 5 (5) on the outer peripheral surface of the oil passage 5.
M:S:However, when aligning and aligning the fuel injections 1 of the injection pumps of multiple cylinders, pull out the opening, handle, and door 6, and use a tool such as a dry gusset to adjust the adjustment member 72. t↓Move. Then, due to the cooperation between the eccentric pin 70 and the retaining groove (56), the force of the plunger guide 62;
1 and around the axis, the relative position of the plunger with respect to the starvation sleeve 38 changes. In other words, the relative position of the control hole 60 with respect to the control groove 58 changes, so it corresponds to each soling. Fine adjustment of the injection amount of the mass injection port/f is carried out. After the injection timing adjustment is completed as described above, the /-le plug 88 is screwed on, the air manometer 78 is removed, and the discharge valve 16 and spring 2o again to fix the discharge valve holder 18 in place, and then tighten the blade opening, knife, and door 6 to prevent the plunger 24 from rotating around the axis, and all work is completed. .

As described above, the method for adjusting the injection timing of a fuel injection pump according to the present invention includes a barrel housed in a housing, a barrel inserted into the barrel so as to be slidable in the axial direction,
a spring-loaded discharge valve mounted within the barrel; a pump chamber bounded within the barrel by the discharge valve and one end surface of the granger; a fuel chamber within the barrel formed surrounding the cyrano gloss; a control sleeve slidably fitted to the outside of the plunger in the fuel chamber; A control groove provided on one of the outer circumferential surface of the cyrano gloss and the control sleeve at an angle with respect to the axis of the syringer for shutting off, a control hole provided on the other of the outer circumferential surface of the plunger and the control sleeve and cooperating with the control groove, and the control an injection amount control member that rotates the sleeve around the plunger axis; and an injection amount control member that is disposed on a control shaft substantially orthogonal to the plunger axis and engages with the control sleeve so that the sleeve is relative to the plunger in the syringe axis direction. The fuel injection timing control member is provided with an injection timing control member whose displacement is adjusted to adjust the fuel injection timing, and the injection timing control member is fixed on the control shaft so as to be adjustable around its axis. , the above-mentioned discharge valve is removed, and the fuel outlet downstream of the discharge valve is connected to a pressurized air source via an air manometer to force-feed pressurized air to the above-mentioned pump chamber, and to adjust the normal flow rate. Remove the Solprada blocking the opening, displace the control sleeve upwards or downwards via the injection timing control member, and measure the moment when the control groove is opened or closed by the vertical sleeve on the air manometer. The invention is characterized in that the injection control member is fixed on the control shaft at that position, and the injection timing of the fuel injection pump can be quickly, easily and reliably fine-adjusted and aligned with respect to the plurality of seven rings of the Ennon. It is extremely useful because it can be done.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the entire pump showing an embodiment of the method of the present invention, Fig. 2 is a sectional view of the main part taken along the line ■-■ in Fig. 1, and Fig. 3 is a side view of the pump in Fig. 2. The cross-sectional view and FIG. 4 are exploded perspective views showing the injection amount adjusting portion of f'/g shown in FIG. 1 of the broom. ]0...Housing 24...Plunger](5
・Discharge valve 38... Control sleeve 42...
・Control axis 78...Air manometer 44...
- Injection timing control member 82...Reducing valve 54...Control rack 84...Compressed air valve 58...Control groove 88.../-Le plug 60...Control hole Fig. 2

Claims (1)

[Claims] A barrel stored in a housing, a plunger slidably inserted in the barrel in the axial direction, a spring-loaded discharge valve mounted in the barrel, and the discharge valve and one end surface of the plunger. a pump chamber confined within the barrel; a fuel chamber within the barrel surrounding the plunger; a control sleeve slidably fitted outside the plunger within the fuel chamber; one end opening into the pump chamber; an oil passage in the plunger, and a control groove provided on the outer circumferential surface of the plunger and one of the control sleeves at an angle with respect to the plunger axis in order to communicate or cut off communication between the pump chamber and the fuel chamber via the oil passage; , a control hole provided on the other of the outer peripheral surface of the plunger and the control sleeve and cooperating with the control groove, an injection amount control member for rotating the control sleeve around the plunger axis, and a control substantially orthogonal to the plunger axis. an injection timing control member disposed on the shaft and engaged with the control sleeve to adjust the relative position of the sleeve with respect to the plunger in the axial direction of the plunger to adjust the fuel injection timing; wherein the member is configured to be fixedly adjustable about the axis on the control shaft, wherein the discharge valve is removed and the fuel outlet downstream of the discharge valve is injected with pressurized air via an air manometer. the control sleeve is connected to the power supply and pumped pressurized air to the pump chamber, and the seal plug that normally blocks the adjustment opening of the housing is removed, and the control sleeve is moved upwardly or downwardly through the injection timing control member. The air manometer detects the moment when the control groove is opened or closed by the control sleeve, and the injection control member is fixed on the control shaft at that position. Timing adjustment method.