JPS6132111Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field and background] The present invention is a small and compact in-line fuel injection pump, in particular a fuel injection pump that can finely adjust the injection amount in response to sudden changes in oil temperature. Regarding injection pumps.

Generally, with the advent of small diesel engines,
The space, weight, and cost of the fuel injection pump in the entire engine are increasing.
In particular, from an economic standpoint, fuel injection pumps that are simpler, smaller, and lighter are required. Additionally, fuel oil tanks are also required to be smaller in capacity.

For example, in a constant-stroke type plunger that is metered by a control sleeve, which has already been developed by the present applicant, the rotation and vertical movement of the control sleeve fitted under the body of the plunger causes the suction port to be Sleeve metering type fuel injection pumps that measure fuel by opening and closing are known. There is a need for the development of a small parallel fuel injection pump in which a plurality of fuel injection pumps having such a structure are arranged in parallel. To explain this in more detail, as is well known,
There is a unit injection pump for each cylinder, which is said to be an independent type, and each injection pump is individually piped to the injection nozzle of each cylinder. Bottle-type fuel injection pumps are suitable for high-speed engines because they ensure a reliable supply of fuel, but on the other hand, they require lubricating oil for the pump section, and there are controls that engage the control rack on the outside of the barrel. Since there are many overlapping parts such as insertion and insertion of the sleeve, there were problems such as bulkiness. Therefore, there is a demand for the development of a compact, in-line fuel injection pump having a sleeve metering mechanism.

[Conventional technology and its problems]

In an in-line fuel injection pump equipped with the sleeve metering mechanism described above, there are many sliding parts such as cams and tappets that are subject to high surface pressure, and the amount of frictional heat generated increases accordingly. If an attempt is made to induce a temperature change in the oil and, in particular, to lubricate various parts of the pump with the fuel itself, the temperature change will also be large, creating the problem that the amount of fuel during the plunger stroke will fluctuate.

On the other hand, in a distribution type fuel injection pump that is equipped with a sleeve metering mechanism, has one plunger for the fuel injection pump, and uses the one plunger to forcefully feed fuel to the injection nozzle of each cylinder via a distribution valve, A governor lever that controls the sleeve metering mechanism itself is equipped with an adjustment screw that can be thermally expanded and contracted to cope with the rise of fuel oil in the pump casing.
137617).

However, in this proposal, since a temperature-sensitive actuating member is attached to the governor lever, the amount of control to the sleeve metering mechanism based on the oil temperature is indirect, which makes it difficult for small in-line fuel injection systems such as the present invention. It cannot handle the sudden rise in oil temperature in the pump.

[Means for solving problems]

Therefore, the present invention attempts to deal with sudden changes in oil temperature in so-called mini-in-line pumps while avoiding the problems of such in-line fuel injection pumps and distribution-type fuel injection pumps.

The structure of the present invention will be explained in detail based on the embodiment shown in the drawings.The outline will be explained with reference to FIG. is driven by. On one side of the pump body, there is a governor housing 4.
is attached to form the pump housing as a whole. The main parts will be explained separately below.

First, in the fuel injection pump 1, a plunger 5 has an oil hole 6 in the center, and a control sleeve 7 provided with a control port 8 is inserted into the lower part of the body of the plunger 5.
It is moved up and down by a gear 9 carved on its outer periphery.
As a result, the timing of communication between the oil hole 6 and the control port 8 is controlled, and the amount and timing of fuel are controlled. 1
1 is a tappet, 12 is a roller, 13 is a bowl-shaped spring holder, 14 is a barrel, 15 is a valve holder, 16 is a high pressure pipe installation screw leading to a fuel injection pump, 17 is a barrel holder, 18 is a delivery valve, 19 is a valve The seat 20 is a wall extending from the pump body 3 and partitioning adjacent fuel injection pumps 1, and the wall 20 is provided with a communication hole 21. Further, although the roller 12 is held by the tappet 11, the axial direction of the roller is restricted by the camshaft 2.
A roller guide pin 23 is rotatably inserted into the outer peripheral end of the bearing metal 22 and the lower end of the wall portion 20.
It is done by and.

Next, regarding the camshaft 2, the camshaft 2 is suspended horizontally on the pump body 3 below the fuel injection pump 1 arranged in a row, and the large-diameter bearing portions 25 and 26 provided on both sides of the camshaft 2 are mounted on the pump body 3. It is supported by the pump body 3 via metals 22 and 24. One outer end of the camshaft 2 is driven by a crankshaft (not shown) via a gear (not shown). The diameters of these bearings 25 and 26 are set within the range of vertical movement of the roller 12 by the cam 27 in order to prevent the roller 12 from moving in the axial direction. A spline 29 for the vane pump 28 and a weight support 38 is carved on the other outer end of the camshaft 2, and a governor weight spindle 31 that is slid by a governor weight 30 is fitted further outside the spline 29. An insert 32 is provided. Note that the symbol E indicates an engine outer wall, and F indicates a flange fixed to the engine outer wall E with bolts B.

Next, regarding the vane pump 28, the vane pump 28 is further outside the bearing portion 26 of the camshaft 2, and includes a side casing 33, a central casing 34, a vane boss 35, and another side casing 36 (the thrust of the governor weight 30). The camshafts 2 are arranged side by side in a skewered manner. These members 33, 34,
35 and 36 are fixed to the pump body 3 with three bolts 37. The boss 35 is provided with a spline that engages with the spline 29 to rotate the eccentric piston and vane of the vane pump 28. With the vane pump 28, fuel is pressurized (approximately 10 kg/cm ² ) from a fuel tank (not shown) into the pump housing formed by the pump body 3 and the governor housing 4, so that the housing is filled with fuel. is filled with.

Next, regarding the governor device, the weight support 38 is formed into a donut shape, and a spline that engages with the spline 29 of the camshaft 2 is carved in the center of the weight support 38, and a protrusion is provided on the plate surface of the weight support 38. Four governor weights 30 are provided on the protrusion so that they can be opened and closed using weight pins 39. governor weight 30
has a pawl 40, which is the governor spindle 31.
If the engine speed, that is, the rotation of the camshaft 2 increases, the governor weight 3
0 opens, advances the governor spindle 31 with its pawl 40, and holds the head of the governor spindle 31 with the governor link 42 (only a portion of which is shown).
As a result, the rack 49 shown in FIG.
51 in a direction perpendicular to the paper surface. Note that when the governor weight 30 opens, its thrust is transmitted to the weight support 38, and the weight support 38
Since the side casing 36 of the vane pump 28 receives the thrust, there is no need to provide a thrust bearing on the camshaft 2 itself.

Note that 43 indicates an injection amount limiting device that adjusts the governor link 42 from the outside, and 44 indicates an overflow valve.

In the in-line fuel injection pump of this embodiment having the above configuration, the camshaft 2 driven by the crankshaft rotates the cam 27, the vane pump 28, the governor weight 30, etc., and the vane pump 28 causes the Fuel is pressurized into the pump housings 3 and 4 from the fuel tank to fill them. Also, cam 2
7, the plunger 5 of each fuel injection pump 1 is reciprocated to intermittently pump the fuel filled around the tappet 11 to a fuel injection valve (not shown). Further, the governor weight 30 opens and closes depending on the magnitude of the engine rotation speed, controls the governor link 42, and performs metering control of each fuel injection pump 1.

In particular, in this embodiment, as shown in FIG. 2, at the lower end of the vertically long oil hole 6 that communicates the head of the plunger 5 with the lower part of the body, there is an oil leak port on the opposite side of the suction port 45. 46, and an inclined metering groove 47 is provided near the opening of the oil leak port 46 on the outer peripheral surface of the plunger 5. Further, a ring-shaped control sleeve 7 is fitted under the body, and a control port 8 is provided in the ring of the control sleeve 7.

Therefore, the control sleeve 7 is temporarily fixed, and the plunger 5 is moved to the cam 27.
, the suction port 45 is closed by the control sleeve 7, and the oil leak port 46 is closed by the control sleeve 7.
The fuel in the oil chamber and the oil hole 6 at the head of the plunger 5 is pressurized until the control port 8 communicates with the fuel injection valve 18, and the fuel in the oil chamber and the oil hole 6 at the head of the plunger 5 is pressurized, the delivery valve 18 is opened, and the fuel is fed under pressure to the fuel injection valve.

If it is desired to increase the amount of fuel to be injected, the control sleeve 7 is rotated by the reciprocating movement of the metering rack 49 that meshes with the gear 9, so that the control port 8 is positioned above the metering groove 47. As a result, the pressurizing stroke of the plunger 5 is lengthened and the amount is increased.

Furthermore, the present invention particularly comprises the metering rack 49 as shown in FIG. That is, the oil temperature in the pump housings 3, 4 increases rapidly due to various factors such as frictional heat due to engine operation, but this rapid increase reduces the volumetric efficiency of the fuel oil entering the plunger 5. The present invention finely adjusts this volumetric efficiency.

That is, when the engine speed increases, the governor link 30 shown in FIG. 1 opens, causing the governor spindle 31 to protrude.
1, one end of the governor link 42 is moved.
Then, as shown in FIG. 3, the governor link 4
The other end of the metering rack 49 is connected to one end of an outer cylinder 53 that houses the metering rack 49, and as the governor link 42 is displaced, the outer cylinder 53 is moved from side to side. Inside the outer cylinder 53, a return spring 54 is built into one end of the metering rack 49, and at the other end a wax pellet 56 with a piston 55 on the inside is caulked and fixed to the outer cylinder 53. Since the control sleeve 7 side of the outer cylinder 53 is notched, the metering rack 49 and the control sleeve 7 are notched.
can be meshed with. Therefore, by displacement of the governor link 42, the outer cylinder 53 and the metering rack 49 are integrated and moved from side to side to increase or decrease the amount of fuel to be injected. And pump housing 3,
If the oil temperature in 4 rises, the wax pellet 56
Since the oil noise in the vicinity of .
9 to the left in the figure, and control sleeve 7.
Finely adjust the position to increase the injection amount.

In addition, in FIG. 3, 57 indicates a guide screw for the outer cylinder 53 and the metering rack 49, and in FIG. 1, 58 indicates a lid body.

[Effect of idea]

In summary, since the present invention is a discharge amount metering device for a fuel injection pump as described in the claims of the utility model registration, it has the following effects.

Since the fuel injection pump is attached to the engine, the fuel oil rises due to heat conduction from the engine due to engine operation and agitation due to the rotation of the governor weight. Frictional heat is added due to the surface pressure caused by pushing up the lower ends of multiple plungers, and since it is a small pump, the fuel storage capacity of the pump housing is also small, so the fuel that overflows from these plungers is also added, and the overall , the oil temperature inside the pump housing will rise rapidly. The present invention directly adjusts the oil temperature in response to such a sudden increase in oil temperature, so the response is sharp and accurate, and the discharge amount adjustment device is suitable for small, in-line fuel pumps equipped with a sleeve metering mechanism. It can be done. In particular, since a single rack rotates multiple control sleeves, multiple plungers can be rotated at once.
Unlike conventional parallel fuel injection pumps that are rotated by a book rack, they operate easily, so the temperature-sensitive actuator attached to the rack operates quickly without resisting other parts. Can be done.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the entire embodiment of the present invention;
The figure shows a partial sectional view from A to A in FIG. 1, and FIG. 3 shows a sectional view of only the metering rack. 5...Plunger, 49...Measuring rack, 5
6...Wax spell.

Claims (1)

[Scope of utility model registration request] A camshaft is horizontally suspended at the bottom of the pump housing, and a plurality of cams are provided on the camshaft, and these cams push up the lower ends of a plurality of upright plungers. An oil hole is drilled in the center and partway through the oil hole, and the fuel press-fitted into the pump housing is introduced into the oil hole, and a control sleeve, which is a sleeve metering mechanism, is installed to control this introduction. A long rack parallel to the camshaft is fitted into the plunger and engaged with a gear carved on the outer periphery of the control sleeve, and the camshaft end in the pump housing is fitted with a long rack parallel to the camshaft. A small, in-line fuel injection pump is provided with a governor mechanism having a governor weight, and the rack is controlled by the governor mechanism, and the long rack is immersed in fuel oil with a return spring and a temperature sensor. 1. A discharge amount adjusting device for a small, parallel-type fuel injection pump, characterized in that an actuating body is attached and the movement of the rack corresponds to a sudden rise in fuel oil temperature within a pump housing.