JP4612149B2 - Electronic injection mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pump nozzle unit or pump conduit nozzle as an electronic injection mechanism for fuels having a higher viscosity and operating temperature compared to diesel fuel, such as heavy oil, mechanically or hydraulically A high-pressure injection pump that is driven by a fuel tank, a supply conduit that supplies fuel from a fuel tank to the high-pressure injection pump via a low-pressure transport pump, and a discharge conduit that leads fuel from the high-pressure injection pump to the low-pressure pump chamber The low-pressure circuit is provided, and the high-pressure injection pump has a pump cylinder, and is supplied from the fuel tank to the pump cylinder through the supply conduit by a low-pressure transport pump. The fuel is loaded with the required fuel pressure, and has a magnet valve, and the magnet valve For control, the to low-voltage circuit of the discharge conduit, or is adapted to control the fuel delivery amount by the high-pressure injection pump to the connected pores in the injection nozzle, the magnet valve, the magnet, and the movable element plate, to those of the type which is composed of a linked control piston mover plate.
[0002]
[Prior art]
In conventional injection mechanisms, the control piston is actuated directly via hydraulic fluid. The fuel to be injected is used as the hydraulic liquid. A high operating temperature is generated in the magnet of the magnet valve depending on the viscosity of the fuel used. This leads to failure or damage due to cavitation.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a compact injection mechanism that functions sufficiently even when the viscosity of the fuel is relatively high. Furthermore, the injection mechanism according to the invention must be simple and inexpensive to manufacture.
[0004]
[Means for Solving the Problems]
According to the present invention, the above-described object is a pump nozzle unit as an electronic injection mechanism for a fuel having a higher viscosity and operating temperature than diesel fuel, such as heavy oil. A pump conduit nozzle, provided with a mechanically or hydraulically driven high pressure injection pump, for supplying fuel from a fuel tank to the high pressure injection pump via a low pressure transport pump; and the high pressure A low pressure circuit comprising a discharge conduit for leading fuel from the injection pump to the low pressure pump chamber, the high pressure injection pump having a pump cylinder, within the pump cylinder from the fuel tank by the low pressure carrier pump; the fuel supplied into the pump cylinder via a supply conduit being adapted to be loaded with the required fuel pressure, it has a magnet valve , The magnet valve, for controlling the injection start and the injection amount, the to low-voltage circuit of the discharge conduit, or to control the fuel delivery amount by the high-pressure injection pump to the connected pores in the jet nozzle and is in the, the magnet valve, the magnet, and the movable element plate, in what format is composed of a linked control piston mover plate, connected to said magnet valve and the injection nozzle A pressureless annular chamber is formed in the pump cylinder coaxially with the control piston between the hole and the discharge conduit, and the annular chamber serves as a fuel return conduit leading to the fuel tank. The control piston is formed hollow inside, the inner chamber of the control piston communicates with the annular chamber, and the magnet and the mover plate of the magnet valve are connected to each other. Shielding sleeve and is solved by being shielded from and fuel to the annular chamber by the connected bellows to the shielding sleeve.
[0005]
【The invention's effect】
This allows direct control of the injection process without the assistance of a servo device with additional errors.
[0006]
In a special configuration of the invention, the mover plate and magnet of the magnet valve are shielded from fuel by a shielding sleeve. This avoids heating of the mover plate and the magnet by hot fuel during operation. When the magnet contacts only the air without contacting the hot fuel, the distance between the mover plate and the magnet can be reduced. This leads to increased magnetic force and reduced switching time.
[0007]
In yet another particular configuration of the invention, a shielded chamber surrounding the mover plate and the magnet is flowed by air or cooling medium through the holes during operation. This prevents high fuel temperatures, for example as high as 140 ° C., from damaging the magnet.
[0008]
According to yet another particular configuration of the invention, the open valve position in which the pump chamber of the high-pressure injection pump and the low-pressure chamber formed in the pump cylinder coaxially with respect to the control piston communicate with each other; Between the closed valve position, the control piston is guided in a guide sleeve made of wear-resistant material so as to be able to reciprocate against the preload force of the valve spring, which guide sleeve It is shrink-fitted in the cylinder and sealed by a stopper plate. This guide sleeve has the advantage that it can be easily replaced as a component that is particularly subject to wear. In short, it is not necessary to immediately replace the entire pump cylinder when wear occurs. The low-pressure chamber is useful for ventilation and offers the advantage that fresh fuel is always drawn in.
[0009]
In a further special configuration of the invention, the control piston is formed hollow inside and the hollow chamber of the control piston is formed in the pump cylinder coaxially to the control piston in the region of the valve spring. And communicates with a non-pressure annular chamber that communicates with the fuel tank through a hole. Fuel leaks that occur during operation are collected in the annular chamber and returned to the fuel tank.
[0010]
In a further special configuration of the invention, a sealing element is incorporated in the shielding sleeve and a bellows extending to the control piston is attached to the shielding sleeve. This shielding sleeve serves as a holding body for the valve spring. The bellows additionally serves to shield the mover plate and the magnet.
[0011]
In a further special configuration of the invention, the magnet is thermally isolated from the pump cylinder and fuel by an intermediate plate made of a special material. This ensures a reliable function of the magnet.
[0012]
Other advantages, features and details of the present invention will become apparent from the following description in which one embodiment of the invention has been described in detail with reference to the drawings. In that case, the features described in the claims and the specification respectively have the inventiveness individually or in any combination.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be described with reference to the illustrated embodiment.
[0014]
In FIG. 1, a pump cylinder of a high pressure injection pump is denoted by reference numeral 1. A part of the pump chamber 2 is seen in the lower part of the pump cylinder 1 as viewed in FIG. The pump chamber 2 communicates with the injection nozzle 6 via holes 3 and 4 and a high-pressure conduit 5.
[0015]
The fuel to be injected is transported from the fuel tank 8 into the low pressure pump chamber 10 via the low pressure transport pump 9. From this low-pressure conveying pump chamber 10, the fuel to be injected reaches the low-pressure chamber 12 formed in the section 14 having the increased diameter of the through hole 13 in the pump cylinder 1 via the supply conduit 11.
[0016]
A guide sleeve 16 is shrink fitted in the through hole 13. The guide sleeve 16 is made of a special wear-resistant material. On the right side of FIG. 1, the through hole 13 is closed by a stopper plate 17. A control piston 18 attached to a valve incorporated in the pump cylinder 1 of the high-pressure injection pump comes into contact with the stopper plate 17. In the open position of the valve control piston 18 is pressed against the stopper plate 17 by the valve spring 2 9.
[0017]
In the opened valve position, the high-pressure pump chamber 2 communicates with the low-pressure chamber 12 through the hole 3 and through the valve seat 20 and further through the port 21 acting as a throttle. The low pressure chamber 12 itself communicates with the low pressure pump chamber 10 via the discharge conduit 15.
[0018]
The control piston 18 is formed hollow inside. The inner chamber 19 of the control piston 18 communicates with the annular chamber 23 by two passages 22 formed in a section 24 having the enlarged diameter of the through-hole 13 coaxially with the end of the control piston 18. Has been. The control piston 18 formed as a hollow cylinder has four sections 25, 26, 27, 28 having different diameters. Section 28 has a slightly larger diameter than section 26. The diameter of section 27 is smaller than the diameter of sections 26 and 28, but larger than the diameter of section 25. A valve seat 20 is formed between the section 27 and the section 28 of the control piston 18. A bellows 30 is mounted in the section 25 between the valve spring 29 and the control piston 18. The end of the bellows 30 closer to the free end of the control piston 18 is fixed to the shielding sleeve 31. A valve spring 29 is also supported on the shielding sleeve 31. A sealing element 32 is arranged between the shielding sleeve 31 and the pump cylinder 1. The shielding sleeve 31 is fixed to an intermediate plate 33 made of a heat insulating material.
[0019]
The intermediate plate 33 is disposed between the pump cylinder 1 and the magnet 35. The magnet 35 cooperates with a mover plate 36 fixed to the control piston 18 by a screw 37. When the magnet 35 is operated, the control piston 18 moves to the left as viewed in FIG. 1 and closes the valve seat 20. Control of the magnet 35 is performed via a control unit 38.
[0020]
Holes 39 and 40 are provided in the intermediate plate 33, and the cooling medium can flow into and out of the chamber 41 shielded from the fuel by the shielding sleeve 31 through these holes.
[0021]
The injection mechanism according to the present invention functions as follows.
[0022]
In the opened state, the valve spring 29 keeps the valve seat 20 open and presses the control piston 18 against the stroke stopper 42 formed on the stopper plate 17. In this opened valve position, the low pressure pump chamber 10 and the high pressure pump chamber 2 communicate with each other. As a result, filling of the high-pressure pump chamber 2 is guaranteed and conveyance to the injection nozzle 6 is prevented.
[0023]
When the magnet 35 controlled by the control unit 38 is energized, the control piston 18 is drawn to the valve seat 20. The diameter of the valve seat 20 corresponds to the diameter of the section 26 of the control piston 18. The control piston 18 occupies a closed valve position and fuel transfer to the injection nozzle 6 is started.
[0024]
The duration of the control signal of the control unit 38 defines the amount of fuel injected. Upon termination of the control signal, the control piston 18 moves to the stroke stopper 42 based on the preload force of the valve spring 29 and the difference in diameter between the sections 26 and 28 of the control piston 18. At that time, the high-pressure conduit 5 is released by communication with the low-pressure pump chamber 10. This causes the end of injection.
[0025]
The control piston 18 is guided in the guide sleeve 16. The guide sleeve 16 is shrink fitted on the pump cylinder 1 and sealed against the low pressure pump chamber 10 by a stopper plate 17. The stroke movement of the control piston 18 until reaching the stroke stopper 42 is hydraulically buffered based on the difference between the diameter of the section 28 of the control piston 18 and the diameter of the step 44 formed at the end of the control piston 18. The
[0026]
The fuel leak is collected in the pressureless annular chamber 23 and discharged to the fuel tank 8 through the hole 45 and the collecting conduit 46.
[0027]
The mover plate chamber and the magnet chamber 41 are sealed against the non-pressure annular chamber 23 by the shielding sleeve 31. As can be clearly seen from FIG. 2, the bellows 30 is fixed to the shielding sleeve 31. The bellows 30 is sealed by a seal ring 49 at the control piston 18.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a part of an injection mechanism according to the present invention.
FIG. 2 is an enlarged view showing a part of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pump cylinder, 2 Pump chamber, 3, 4 holes, 5 High pressure conduit, 6 Injection nozzle, 8 Fuel tank, 9 Low pressure conveyance pump, 10 Low pressure pump chamber, 11 Supply conduit, 12 Low pressure chamber, 13 Through hole, 14 Through hole 15 discharge conduit, 16 guide sleeve, 17 stopper plate, 18 control piston, 19 inner chamber, 20 valve seat, 21 port, 22 passage, 23 annular chamber, 24 through hole division, 25, 26, 27, 28 Control piston section, 29 valve spring, 30 bellows, 31 shielding sleeve, 32 sealing element, 33 intermediate plate, 35 magnet, 36 mover plate, 37 screw, 38 control unit, 39, 40 hole, 41 shielded chamber, 42 stroke stopper, 46 collecting conduit, 49 seal ring

Claims (5)

A pump nozzle unit (PDE) or pump conduit nozzle (PLD) as an electronic injection mechanism for fuels having a higher viscosity and operating temperature than diesel fuel, such as heavy oil, mechanical or liquid A high-pressure injection pump that is driven in a pressure manner, a supply conduit (11) for supplying fuel from a fuel tank (8) to the high-pressure injection pump via a low-pressure transfer pump (9), and the high-pressure injection pump Is provided with a low pressure circuit comprising a discharge conduit (15) for leading fuel to a low pressure pump chamber (10), the high pressure injection pump having a pump cylinder (1), the pump cylinder (1) the inner, the fuel supplied to the pump cylinder (1) in via the supply conduit (11) from a fuel tank (8) the load is at a predetermined fuel pressure by a low pressure conveying pump (9) It has become so that has a magnet valve (18,35,36), the magnet valve (18,35,36) is for control of the injection start and the injection amount, the low-pressure circuit The amount of fuel transported by the high-pressure injection pump into the discharge conduit (15) or into the hole (4) connected to the injection nozzle (6) is controlled, and the magnet valve comprises a magnet (35 ) and, the movable element plate (36), in what format that is configured from a control piston connected to the movable element plate (36) (18),
Coaxially with respect to the control piston (18) between the magnet valve (18, 35, 36) and the hole (4) connected to the injection nozzle (6) and the discharge conduit (15). A pressureless annular chamber (23) is formed in the pump cylinder (1), and the annular chamber (23) communicates with a hole (45) as a fuel return conduit communicating with the fuel tank (8). The control piston (18) is hollow inside, the inner chamber (19) of the control piston (18) communicates with the annular chamber (23), and the magnet (35) and the magnet valve The movable plate (36) is shielded from the annular chamber (23) and from the fuel by the shielding sleeve (31) and the bellows (30) connected to the shielding sleeve (31). An electronic jet characterized by Mechanism. Passing flows by an air or cooling medium through the magnet chamber (41) is a hole (39, 40) during operation between the armature plate (36) and a magnet (35) and said shield sleeve (31), wherein Item 2. The injection mechanism according to Item 1 . A low pressure chamber (12) formed in the pump cylinder (1) coaxially with the control piston (18) and communicating with the low pressure pump chamber (10) and a pump chamber (2) of the high pressure injection pump communicate with each other. The control piston (18) is preliminarily placed in the guide sleeve (16) made of wear-resistant material between the open valve position and the closed valve position to block the communication. It is reciprocally guided against the pressure, the guide sleeve (16) have been shrunk to the through-hole (13) in the pump cylinder (1), closing the through-hole (13) The injection mechanism according to claim 1 or 2 , which is sealed by a stopper plate (17). A sealing element (32) for sealing the movable element plate (36) and the magnet (35) from the annular chamber (23 ) is incorporated in the shielding sleeve (31), and the shielding sleeve (31) , the control piston (18) is bellows (30) which extends to the attached, any one of claims injection mechanism of claims 1 to 3. Magnet (35) is thermally insulated from the intermediate plate of insulating material (33) the pump cylinder (1) by the fuel, any one of claims injection mechanism of claims 1 to 4.

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