JPS6121572Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection pump in which the amount of fuel to be injected and the timing of fuel injection are controlled by a single annular valve.

The present invention also provides an annular valve type fuel injection pump in which the advance angle controller is moved forward and backward in the axial direction according to the feed pressure, which changes in proportion to the rotational speed of the engine. This was done with the purpose of reducing the size and weight of the fuel injection pump by making it possible to control the fuel injection pump. While making it possible to pump fuel,
An annular valve is provided on the plunger, the annular valve being capable of opening and closing an oil hole formed on the outside of the plunger across the top surface and side circumferential surface of the plunger in a fuel chamber formed in the middle part of the plunger insertion hole. The annular valve is fitted so as to be rotatable and slidable relative to the plunger, and the annular valve is appropriately rotated relative to the plunger using a metering operator to change the opening/closing timing of the oil passage hole of the plunger. The injection timing of the fuel can be controlled by appropriately displacing the annular valve in the axial direction of the plunger with an advance angle operator, while the advance angle operator is connected to the pump. The fuel injection pump is controlled by a timer piston which is provided within the casing and is movable in the axial direction and is moved back and forth in the axial direction in response to the feed pressure that changes in proportion to the engine rotational speed. It is characterized by its smaller size and lighter weight.

Hereinafter, the fuel injection pump of the present invention will be explained using a distribution type fuel injection pump Z for a four-cylinder diesel engine shown in FIGS. 1 to 5 as an example. As shown in the figure, there is a fuel pressurizing part A for pressurizing the fuel, and the high-pressure fuel pressurized by the fuel pressurizing part A is sequentially delivered to four fuel injection valves (not shown) installed on the engine body side. It has a fuel distribution section B for pressure feeding.

The fuel pressurizing section A includes a plunger 2 that is slidably inserted into a pushless type plunger insertion hole 18 formed in the axial center of the pump casing 1;
It has an annular valve 3 that is relatively rotatably and slidably fitted into the fuel chamber 14 formed in the middle part of the plunger fitting hole 18 on the outside of the plunger 2. By reciprocating the plunger 2 using the spring force of the cam 24 and the plunger spring 29, the fuel in the fuel chamber 14 passes through the oil passage hole 10 formed in the plunger 2, and is fed into a fuel filler formed on the top surface of the plunger. It is fitted into the pressure chamber 15 to pressurize it, and is forced to be fed to the delivery chamber 17 side via the delivery valve 5.

In the fuel injection pump Z of this embodiment, four protrusions 24a, 2 are provided on the outer peripheral surface of the cam 24.
4a, . . . are formed at equal intervals in the circumferential direction so that the plunger 2 can reciprocate four times for each revolution of the camshaft 11.

The fuel, which is pressurized four times per revolution of the camshaft 11, is distributed to four distribution oil passages in a fuel distribution section B, which will be described later, and is distributed to four cylinders (not shown) in the engine body. The fuel is sequentially supplied to each attached fuel injection valve (not shown).

The annular valve 3 has an outlet 10a (slanted lead part) of the oil passage hole 10 of the plunger 2 on one side of its side peripheral surface 3a.
An oil release hole 9 that communicates with or does not communicate with the annular valve 3 is provided in the radial direction, and two positions perpendicular to the non-oil hole 9 and opposite to each other across the axis of the annular valve 3 are provided with oil release holes 9 that communicate with or do not communicate with the annular valve 3. A vertical groove 44 extending in the axial direction of the annular valve 3 and a lateral groove 45 extending in the circumferential direction are respectively formed.
The vertical groove 44 and the horizontal groove 45 each have a fuel chamber 1
4, the eccentric head 31 of the metering operator 30 is attached from one side 1a of the pump casing 1, and the advance angle operator 32 is attached from the other side 1b.
Eccentric heads 33 are fitted respectively. This fuel injection pump Z has a metering operator 30
is rotated by an appropriate governor device (not shown) engaged with a metering operation lever 46 attached to the outer end 30a of the metering operator 30, so that the annular valve 3 is moved relative to the plunger 2. The amount of fuel to be injected is controlled by appropriately rotating the oil passage hole outlet 10a of the plunger 2 and changing the communication timing between the oil hole outlet 10a of the annular valve 3 and the oil escape hole 9 of the annular valve 3.
Further, the fuel injection timing is determined by rotating the advance angle controller 32 by a timer piston 35 that is moved forward and backward in the axial direction in accordance with the feed pressure that changes in proportion to the engine speed. is adjusted by displacing the plunger in the axial direction.

That is, the timer piston 35 is
As shown in FIG. 4, it is formed in the pump casing 1 at a position above the advance angle operation element 32 in a direction perpendicular to the advance angle operation element 32, and has one end thereof connected through a hydraulic oil supply passage 83. The piston is slidably fitted into a piston fitting hole 36 communicating with the fuel chamber 14, and one end surface 35 of the piston fitting hole 36 communicates with the fuel chamber 14.
It is moved forward and backward in the axial direction by the difference between the fuel pressure acting on the side a and the spring force of the timer spring 38 acting on the other end surface 35b. When the timer pin 35 moves back and forth in the axial direction, the engaging protrusion 37 protruding from the middle part of the timer pin 35 engages with the timer lever 34 attached to the outer end of the advance angle controller 32. The corner operator 32 is rotated as appropriate via the timer lever 34. Further, the fuel pressure in the fuel chamber 14, which is pressure-controlled in proportion to the engine speed, acts on one end surface 35a of the timer piston 35 by the feed pump 22, which rotates in conjunction with the engine output shaft (not shown). .

Note that the reference numeral 50 in the figure is a fuel inlet.

Further, the advance angle characteristic is adjusted by adjusting the screwing amount of an adjustment screw 39 screwed onto the outside of the timer spring 38.

Furthermore, the maximum advance amount by the timer piston 35 is adjusted by, for example, appropriately setting the maximum feed pressure using the relief valve 26.

The fuel distribution part B is coaxially fitted to the cylindrical distribution rotor fitting part 43 formed at the lower end 1c of the pump body 1 and to the outside of the distribution rotor fitting part 43 so as to be relatively rotatable. By rotating the distribution rotor 4 relative to the distribution rotor fitting part 43, the high-pressure fuel in the fuel pressurizing chamber 15 is transferred to the engine body side as described later. The fuel can be sequentially supplied to four fuel injection valves.

The distribution rotor 4 is fitted on the outside of the distribution rotor fitting part 43 of the pump casing 1 as shown in FIGS. As the camshaft 11 rotates, it is caused to rotate synchronously with the camshaft 11 on the outside of the distribution rotor fitting portion 43. Note that the rotation ratio between the camshaft 11 and the distribution rotor 4 is set to 1:1 in this embodiment. Further, this distribution rotor 4 has a high-pressure oil circumferential groove 5 formed in the outer peripheral surface 43a of the distribution rotor fitting portion 43 in the middle part of the inner peripheral surface 4a.
3 (hereinafter referred to as the first high-pressure oil circumferential groove 53) and a high-pressure oil circumferential groove 54 (hereinafter referred to as the second high-pressure oil circumferential groove 5)
4) and a distribution groove 55 that communicates with the second high-pressure oil circumferential groove 54 and extends in the vertical direction.
On the other hand, the first high-pressure oil circumferential groove 53 on the distribution rotor fitting part 43 side is connected to a high-pressure oil passage 52 (hereinafter referred to as a second high-pressure oil passage 52) formed vertically penetrating inside the pump casing 1. A high pressure oil passage 51 (hereinafter referred to as the first high pressure oil passage 5) extending through the holder 6
1) and communicates with the delivery chamber 17. A first high pressure oil passage 5 formed in the pump casing 1 from this delivery chamber 17
1, the second high pressure oil passage 52, the first high pressure oil circumferential groove 53, and further the second high pressure oil circumferential groove 5 on the distribution rotor 4 side.
A series of high-pressure oil passages that reach the distribution groove 55 through the main high-pressure oil passage 55 will be referred to as a main high-pressure oil passage 56 below.

On the other hand, on the outer circumferential surface 43a of the distribution rotor fitting portion 43 and at a position above the first high pressure oil circumferential groove 53, the distribution groove 55 is formed as the distribution rotor 4 rotates.
Four longitudinal grooves 60, 63, 6 that alternatively communicate with
6 and 69 are formed at equal intervals in the circumferential direction.
Further, each of the vertical grooves 60, 63, 66, 69 is communicated with oil passage holes 61, 64, 67, 70, which open in the upper end surface 1d of the pump casing 1, respectively. The vertical groove 60 and the oil hole 61, the vertical groove 63 and the oil hole 64, the vertical groove 66 and the oil hole 67, and the vertical groove 69 and the oil hole 70, which communicate with each other, are connected to each cylinder ( (not shown), and in the following, the first distribution oil passage 59, the second distribution oil passage 62, the third distribution oil passage 65, and the third distribution oil passage 65 will be described in order. It is called a 4-distribution oil passage 68.

In addition, these distribution oil passages 59, 62, 65, 68
High pressure pipe fittings 28, 28, .

Furthermore, the second high-pressure oil circumferential groove 54 and each vertical groove 60, 63, 66, on the inner peripheral surface 4a of the distribution rotor 4,
69 in the vertical direction, the inner circumferential surface 4a
An upper circumferential groove 72 and a lower circumferential groove 73 are formed along. Furthermore, the upper circumferential groove 72 and the lower circumferential groove 7
3 are communicated with each other via a communication hole 74 formed in the distribution rotor peripheral wall 4b, and
It is communicated with the fuel chamber 14 through an oblique hole 75 formed in the pump casing 1 .

The upper circumferential groove 72, the lower circumferential groove 73, and the communication hole 7
A series of communication passages including the leakage oil return passage 71 and the diagonal hole 75 will be referred to as a leak oil return passage 71 hereinafter.

Note that the distribution rotor 4 is prevented from falling off by a falling-off preventing member 27 provided at the lower end portion 43b of the distribution rotor fitting portion 43.

The fuel injection pump Z configured as described above is removably fastened to a pump mounting portion 48 provided on the side wall 47 of the engine body using mounting bolts 20, 20, . . . .

Next, the operation of the fuel injection pump Z of the illustrated embodiment will be explained. When the camshaft 11 rotates, the plunger 2 is rotated by each projection 24a, 24a, . The fuel in the fuel chamber 14 is sucked into the fuel pressurizing chamber 15 and pressurized, and the fuel in the delivery chamber 1 is reciprocated four times.
7 through the main high-pressure oil passage 56 to the distribution groove 55 side. As the distribution rotor 4 rotates, the high-pressure fuel pumped into the distribution groove 55 is transferred to the first distribution oil passage 59, the second distribution oil passage 59, which selectively communicates with the distribution groove 55.
The fuel is supplied to each fuel injection valve (not shown) attached to each cylinder of the engine body through the distribution oil passage 62, the third distribution oil passage 65, and the fourth distribution oil passage 68.
At this time, leaked oil leaked from the main high pressure oil passage 56 or each distribution oil passage 59, 62, 65, 68 into the sliding contact area between the distribution rotor 4 and the distribution rotor fitting part 43 is transferred to the upper side of the leak oil return passage 71. The fuel is extracted through the circumferential groove 72 and the lower circumferential groove 73 and recirculated to the fuel chamber 14 side.

The amount of fuel to be injected is controlled by rotating the metering operator 30 and rotating the annular valve 3 relative to the plunger 2 using a suitable governor device.

The fuel injection timing is controlled by the timer piston 3 according to the feed pressure which varies in proportion to the engine speed.
5 is appropriately displaced in the axial direction, and the engaging protrusion 37
The advance angle operating member 32 is rotated by the control signal 31 to displace the annular valve 3 in the axial direction of the plunger 2.

Next, to explain the effects of the present invention, the fuel injection pump of the present invention has a timer piston mounted in the pump casing that is moved forward and backward in the axial direction by feed pressure proportional to the engine rotation speed.
Since the advance angle controller is controlled by this timer piston, there is no need to provide a timer device or a link mechanism outside the pump casing, and the fuel injection pump can be made smaller and lighter. There is an effect.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a distribution type fuel injection pump according to an embodiment of the present invention, Fig. 2 is a longitudinal sectional view similar to Fig. 1, Fig. 3 is a transverse sectional view similar to Fig. FIG. 1 is a partial vertical sectional view taken along the line 1, and FIG. 5 is a view taken along the arrow 1 in FIG. 1...Pump casing, 2...Plunger,
2a... Plunger top surface, 2b... Plunger side peripheral surface, 3... Annular valve, 10... Oil passage hole, 14...
Fuel chamber, 18... plunger insertion hole, 30... metering operator, 32... advance angle operator, 35... timer piston.

Claims (1)

[Scope of utility model registration request] Fuel can be pumped by reciprocating the plunger 2 in a plunger insertion hole 18 formed in the pump casing 1, and the plunger 2 can be moved under pressure in a fuel chamber 14 formed in the middle part of the plunger insertion hole 18. 2 on the outside of the plunger 2
An annular valve 3 that can open and close an oil passage hole 10 formed across the top surface 2a and side circumferential surface 2b of the plunger 2 is fitted into the plunger 2 so as to be relatively rotatable and slidable. The amount of fuel to be injected is controlled by appropriately rotating the metering operator 30 relative to the plunger 2 to change the opening/closing timing of the oil passage hole 10 of the plunger 2, and the annular valve 3 By appropriately displacing the advance angle operator 32 in the plunger axial direction, the fuel injection timing can be controlled.
2 can be controlled by a timer piston 35 which is provided in the pump casing 1 so as to be movable in the axial direction and can be moved back and forth in the axial direction in accordance with the feed pressure which changes in proportion to the rotational speed of the engine. A fuel injection pump characterized by: