JPS6228309B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection pump that supplies fuel under pressure to a fuel injection valve attached to a combustion chamber or an intake port of an internal combustion engine such as a gasoline or diesel engine.

Conventionally, this type of injection pump was mainly of the bottle type, but the prior art
Publication No. 80317 discloses a plunger that reciprocates in conjunction with an engine within a plunger barrel having a delivery valve to a combustion injection nozzle;
A fuel passage is provided that communicates with a fuel inflow chamber to which fuel is supplied from a fuel pump driven by the engine, and an adjustment ring is slidably and rotatably fitted to the fuel inflow chamber of the fuel passage. The opening of the fuel port is opened and closed by the adjusting ring during reciprocating movement of the plunger, and the adjusting ring is
The adjustment ring is connected to the load of the engine so that the closed section of the fuel port is changed by its rotation, and the adjustment ring is slid in the direction of the reciprocating movement of the plunger to open and close the fuel port with respect to the reciprocating movement of the plunger. We propose a fuel injection pump that is related to the engine rotational speed so that the timing changes.

However, when sliding the adjustment ring in the reciprocating direction of the plunger according to the rotational speed of the engine, this device provides an eccentric pin at the tip of the adjustment oil,
The eccentric pin is engaged with an annular groove provided on the outer circumferential surface of the adjustment ring, and the adjustment ring is configured to slide in the reciprocating direction of the plunger by rotation of the adjustment shaft. It is configured to rotate according to changes in the rotational speed of the engine using a governor mechanism that is linked to the engine's crankshaft.
The adjustment ring fitted on the reciprocating plunger,
Sliding with an eccentric pin fitted into an annular groove on the outer circumferential surface of the adjustment ring causes twisting in the sliding and requires a considerable amount of force.
The governor mechanism that is linked to the engine crankshaft must generate a large amount of force, that is, it must be large.This, along with the need for the adjustment shaft, results in a complicated structure, and the need for a fuel injection pump. As the engine becomes larger, its weight increases, and the looseness between the eccentric pin and the annular groove causes fluctuations and/or delays in the adjustment control of the fuel injection timing corresponding to the rotational speed of the engine. So it was warm.

The present invention is based on the fact that the fuel pump for sending fuel to the fuel injection pump is driven by the engine, and the discharge pressure of the fuel in the fuel pump is proportional to the rotational speed of the engine. This problem is solved by allowing the adjustment ring in the prior art to slide due to the discharge pressure of the fuel pump.

Therefore, in the present invention, fuel is supplied from the inside of the plunger barrel and a fuel pump driven by the engine to a plunger that reciprocates in conjunction with the engine in a plunger barrel having a delivery valve to a combustion injection nozzle. A fuel passage is provided that communicates with the fuel inlet chamber, and an adjustment ring is slidably and rotatably fitted so that the fuel port, which is the opening of the fuel passage to the fuel inlet chamber, is connected to the fuel inlet chamber during reciprocating movement of the plunger. The fuel injection pump is configured to be opened and closed by the adjustment ring, and the adjustment ring is connected to the outer periphery of the plunger barrel in relation to the load of the engine so that the closed section of the fuel port changes depending on the rotation of the adjustment ring. forms a cylindrical hydraulic chamber extending in the axial direction of the plunger, and connects a discharge passage from the fuel pump to the hydraulic chamber; A piston is slidably inserted into the adjustment ring so that the adjustment ring slides in the direction of reciprocating movement of the plunger.

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, reference numeral 1 denotes a pump body, and the lower part thereof includes a housing 3 that accommodates a drive shaft 2 that rotates in conjunction with the crankshaft (not shown) of the engine. In addition, the main body 1 has a cylinder bore 4 in a direction perpendicular to the drive shaft 2.
It is equipped with The upper body 1 of this cylinder bore 4
A valve holder 5 has a built-in delivery valve 6 and a buffer valve 7.
A plunger barrel 8 located at the center of the cylinder bore 4 is attached to the valve holder 5, and a fuel injection nozzle of the engine (Fig. (However, in the case of a distribution type fuel injection pump, the passage 9 is connected to a distribution valve, and the injection is distributed from the distribution valve to the injection nozzle in each cylinder of the engine), and inside the plunger barrel 8. The lower part of the plunger 10, which is slidably inserted, is slidably held in the sleeve 11 inserted into the lower part of the cylinder bore 4 via the guide piston 12, and the drive shaft 2 has an appropriate dimension with respect to its axis. e. An eccentric crankshaft 13 is provided, and the tip of a crank rod 14 rotatably fitted onto the crankshaft 13 is pivotally connected to the guide piston 12 with a pin 15. The plunger 10 is configured to reciprocate within the plunger barrel 8.

On the other hand, inside the cylinder bore 4, there is a ring-shaped adjustment gear 16 having spur teeth 16' cut into a part of the outer peripheral surface.
The adjustment gear 1
6 is engaged with a slide lever 17 which is slidable by the load of the engine, such as by interlocking with the accelerator, the throttle valve in the engine, or the intake negative pressure, and the adjusting gear 16 is fitted with a slide lever 17 that slides on the plunger 10. The adjustment ring 18 fitted so as to be movable and rotatable is attached, and a part of the upper surface of the adjustment ring 18 is formed into an inclined surface 1.
9, and the height L between the lower surface 20 and the inclined surface 19 is configured to gradually change with respect to the direction of rotation of the ring 18. Further, the inside of the cylinder bore 4 below the adjustment gear 16 and the adjustment ring 18 is formed into a fuel inflow chamber 21, and the inflow chamber 21 is provided with a spring 22 for holding the adjustment gear 16 and the adjustment ring 18, while the plunger 10 is provided with a fuel passage 23 that communicates the inside of the barrel 8 at the top with the fuel inflow chamber 21, and a fuel port 24, which is an opening of the passage 23 toward the fuel inflow chamber 21, is connected to the reciprocation of the plunger 10. The adjustment ring 18 is configured to open and close during the stroke. A cylindrical hydraulic chamber 26 extending in the axial direction of the plunger 10 is formed above the adjusting gear 16 and on the outer periphery of the plunger barrel 8.
A piston 25 is slidably inserted therein, and the piston 25 is brought into contact with the upper surface of the adjustment gear 16.

Reference numeral 27 denotes a fuel pump that is linked to the crankshaft (not shown) of the engine, and its suction side is connected to the fuel tank (not shown) through a passage 28, and its discharge side is connected to the pressure chamber through a passage 29. 26 and branched from the discharge passage 29.
has an orifice 31 and a pilot cut valve 32.
and a pilot type switching valve 33 are provided in series and connected to the fuel inlet chamber 21, and between the supply passage 30 and the return passage 34 to the suction passage 28, the pressure after the orifice 31 is maintained at a constant value. While a relief valve 35 is provided to hold the fuel, when the discharge pressure of the fuel pump 27 rises to the pressure at the set maximum rotation of the engine, the cut valve 32 cuts off the flow of fuel beyond this point, and at the same time, the switching valve 33 shuts off the fuel. The inlet chamber 21 is switched to be connected to the return passage 34, and the fuel in the fuel inlet chamber 21 is sucked back to the fuel pump 27.

Reference numerals 36 and 37 in the figure indicate receiving washers for the spring 22 which also serve as injection timing advance stoppers, and a thrust bearing 38 is provided between the lower receiving washer 37 and the sleeve 11. The orifice 11a provided at the top of the sleeve and the passage 39 provided on the circumferential surface of the sleeve drain surplus fuel in the fuel inlet chamber 21 and the sleeve inner chamber 11' into the housing 3.
The fuel that has escaped into the housing 3 is configured to return to the fuel tank through a passage (not shown), and this returned fuel causes the sliding parts of the guide piston 12, crank rod 14, pin 15, etc. It is designed to lubricate the Further, 40 is for finely adjusting the relative positional relationship between the adjusting gear 16 and the adjusting ring 18, and in this case, a screw is used.

Next, to explain its operation, in the upward stroke of the plunger 10, when the fuel port 24 that opens on the side surface moves up through the adjustment ring 18, when it is completely closed by the adjustment ring 18, the port 24 Since the flow of fuel in and out through the port 24 is completely cut off, the fuel that entered the plunge barrel 8 from the port 24 during the previous downward stroke is
The pressure rises due to the upward movement of the plunger 10, and the fuel is sent from the passage 9 to the fuel injection nozzle via the delivery valve 6 and the buffer valve 7, whereupon the fuel is injected. If the adjustment ring 18 is opened on the upper side of the inclined surface 19, the fuel in the plunger barrel 8 can be transferred to the fuel port 24.
Fuel injection stops by escaping from the plunger barrel. In this way, during the upward stroke of the plunger, the fuel port 24 opening on the side thereof is completely closed by the adjustment ring 18,
In other words, fuel is injected over an area obtained by subtracting the diameter of the fuel port 24 from the height L of the adjustment ring 18. In addition, plunger 1
The fuel that escaped from the fuel port 24 during the rise of 0 is
The fuel returns to the fuel inflow chamber 21 through the gap between the spur teeth 16' of the adjustment gear 16, etc.

The adjustment ring 18 is rotated around the plunger 10 in conjunction with the engine load by means of a lock rod 17 meshing with the adjustment gear 16 to which it is attached, that is, in the direction of arrow A in proportion to the engine load. As the height L between the lower surface 20 and the inclined surface 19 at the fuel port 24 locations gradually increases, the section in which the fuel port 24 is completely closed becomes longer, so that the amount of fuel injected gradually increases. It is controlled and regulated. Further, as the engine speed increases, the discharge pressure of the fuel pump 27 linked to this increases, and this discharge amount enters the pressure chamber 26 and moves the adjustment ring 18 against the spring 22 via the piston 25. Since the plunger 10 is pushed down, the timing at which the adjustment ring 18 closes the fuel port 24 is determined by the plunger 10.
The injection timing is controlled and adjusted in an advance direction in proportion to the engine speed.

To explain this relationship on the lift curve of the plunger shown in FIG. 5, if the start of injection is set to a and the end of injection is set to b when the engine is running at low engine load and no load, then the adjustment ring 18 that is related to the engine load Due to the rotation, b shifts to b', the closed section of the fuel port 24, that is, the fuel injection section expands from _L1 to _L2 , the injection amount increases, and the sliding of the adjustment ring related to the engine speed increases. Due to dynamic displacement, the start of injection a is
a', and the injection timing is controlled to be advanced by θ degrees.

It goes without saying that the adjustment ring 18 may be rotated in relation to the engine load by some other mechanism instead of the rack rod 17.

In summary, the present invention adjusts the fuel injection timing by sliding the adjustment ring in the reciprocating direction of the plunger in relation to the rotational speed of the engine. A cylindrical hydraulic chamber extending in the axial direction is formed, and a discharge passage from the fuel pump is connected to the hydraulic chamber, and the adjusting ring is connected to a plunger in response to changes in the oil pressure in the hydraulic chamber. The piston is slidably inserted into the piston so that it can slide in the direction of reciprocating motion, and the fuel is injected by the discharge pressure of the fuel pump to supply fuel to the fuel injection pump. The timing can be adjusted and controlled according to the rotational speed of the engine, and there is no need for the adjustment shaft with an eccentric pin and the governor mechanism in the prior art, which simplifies the structure and makes the fuel injection pump smaller and lighter. In addition, since there is no wobbling when the adjustment ring slides, the adjustment control of the fuel injection timing relative to the rotational speed of the engine can be performed extremely smoothly and accurately.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view of a pump implementing the present invention;
The figure is a cross-sectional view of FIG. 1, FIG. 3 is an enlarged cross-sectional view of FIG. 1, FIG. 4 is a cross-sectional view of FIG. It is a figure showing a relationship. 1...Pump body, 8...Plunger barrel,
6... Delivery valve, 10... Plunger, 21... Fuel inflow chamber, 23... Fuel passage, 24... Fuel port, 18... Adjustment ring, 17... Rack rod, 2
5...Piston, 26...Hydraulic chamber, 27...Fuel pump, 29...Discharge passage.

Claims (1)

[Claims] 1. A plunger that reciprocates in conjunction with an engine in a plunger barrel having a delivery valve to a combustion injection nozzle has a fuel inlet chamber that is supplied with fuel from a fuel pump driven by the engine and the plunger barrel. A fuel passage communicating with the plunger is provided, and an adjustment ring is slidably and rotatably fitted so that the fuel port, which is the opening of the fuel passage to the fuel inflow chamber, is connected to the adjustment ring during reciprocating movement of the plunger. In the fuel injection pump, the adjusting ring is configured to open and close in relation to the load of the engine so that the closing section of the fuel port changes depending on the rotation of the adjusting ring. A cylindrical hydraulic chamber extending in the axial direction is formed, and a discharge passage from the fuel pump is connected to the hydraulic chamber, and the adjusting ring is connected to a plunger in response to changes in the oil pressure in the hydraulic chamber. A fuel injection pump characterized in that a piston is slidably inserted into the piston so as to be slid in the direction of reciprocating motion.