JP2003184683A - Fuel pump device for fuel system of internal combustion engine and fuel system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily form a fuel pump device and inexpensively manufacture a corresponding fuel system by improving the fuel pump device. <P>SOLUTION: This fuel pump device 20 for a fuel system 10 of an internal combustion engine 12 especially for direct injection has a fuel pump 26, and an electrical drive motor 24 connected with the fuel pump 26. The fuel pump is a radial piston pump 26, and the drive motor 24 and the fuel pump 26 form a unit having one common liquidtight casing 22. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention first of all relates to a fuel pump device for a fuel system of an internal combustion engine, in particular for direct injection, which comprises a fuel pump and an electric drive connected to the fuel pump. And a motor type.

[0002]

2. Description of the Related Art Such a fuel pump device is disclosed in EP072.
It is known from the 5212A2 patent specification. This specification describes a fuel system in which fuel is pumped from a fuel tank to a second fuel pump device by a first fuel pump device and from there to a high pressure region to a fuel injector. Each of the fuel pump devices has one fuel pump and an electric drive motor connected to the fuel pump. The pumping output of both fuel pump devices can be changed via the rotational speed of the electric drive motor,
Can be adjusted.

A disadvantage of the known fuel pump system is that it is difficult to handle and integrate into the fuel system,
Therefore, the cost of constructing the fuel system is high. The pump power also cannot meet the demands at all operating points of the internal combustion engine.

[0004]

[Patent Document 1] European Patent Publication (EP-A2) No. 0725
No. 212

[0005]

SUMMARY OF THE INVENTION The object of the invention is therefore to improve a fuel pump device of the type mentioned at the outset, to make it simpler and to produce a corresponding fuel system at a lower cost. To do so. It is desirable that this fuel pump device can prepare a high injection pressure required for an internal combustion engine that performs direct injection at all operating points of the internal combustion engine.

[0006]

In order to solve this problem, in the structure of the present invention, in the fuel pump device of the type described at the beginning, the fuel pump is a radial piston pump, and the drive motor and the fuel pump are It was designed to form a unit with one common liquid tight casing.

[0007]

By forming the fuel pump as a radial piston pump, it is possible to create the high pressures required in modern fuel systems for internal combustion engines with direct gasoline injection. The fact that the drive motor and the fuel pump form one unit greatly facilitates handling during the formation of the fuel system. This allows one unit to be pre-assembled, consisting of a drive motor and a fuel pump, so that, for example, when forming a fuel system in a motor vehicle, one common part is treated instead of two separate parts. Just enough.

By mounting the drive motor and the fuel pump in one common liquid-tight casing, the handleability of the fuel pump device thus formed is further improved. In this case, such a liquid-tight casing has already been heretofore required for the fuel pump, so that there is little or no additional cost. The drive motor is also mounted in a liquid-tight casing, which ensures that the drive motor is protected against external contamination.
Therefore, it is possible to use an electric motor which has a low pollution tolerance but is efficient, which further increases the efficiency of the fuel pump system. The service life of the fuel pump system is also improved by such measures.

The efficiency of the fuel pump device according to the invention is further improved by not providing the shaft seal device from the fuel pump to the drive motor, which would otherwise be required. Such shaft seal devices always have some wear and leakage. Wear and leaks reduce the efficiency of the fuel pump. The cost is further reduced by not providing a shaft sealing device.

Advantageous further developments of the fuel pump system according to the invention are set forth in the dependent claims.

For example, a fuel pump has a drive shaft with at least one bearing, which drive shaft is at the same time
It is proposed to form the rotor shaft of the drive motor. The fuel pump device formed in this way can be of very compact design, since it is possible to dispense with a separate shaft for the fuel pump on the one hand and the drive motor on the other hand. Overall, relatively few bearings are required for the drive shaft or rotor shaft bearings. This reduces the size and manufacturing costs of the fuel pump system.

In this case, it is particularly advantageous if a liquid-tight cover is provided, which protects the bearing from particles originating from the drive motor. This improves the service life of the bearing and the bearing need not be relatively robust. This further reduces the size and cost of the fuel pump system.

In a particularly advantageous design of the fuel pump device according to the invention, the interior of the casing of the unit consisting of the fuel pump and the drive motor is flowed by fuel at least in the region of the drive motor. This has the advantage that the drive motor can be cooled by the fuel and the efficiency of the drive motor can be improved.

In this case, the flow guide in the inner chamber of the casing of the unit consisting of the fuel pump and the drive motor ensures that the fuel first flows through the drive motor in at least a predetermined region and then to the fuel pump. Formed in the flow path between the drive motor and the fuel pump,
It is particularly advantageous if a filter device, in particular a mesh, is provided.

In such a fuel pump system, the drive motor is best cooled, which favors the efficiency of the drive motor and improves the pumping capacity of the fuel pump system as a whole. In this case, it is possible to prevent clogging in the flow passage of the fuel pump or in the valve device. Such blockages are produced, for example, from brittle materials,
It may be caused by a portion of the drive motor that is separated from the magnet. With such an advantageous design of the fuel pump device according to the invention, a high efficiency is obtained over the entire service life of the device.

The drive shaft of the fuel pump has an eccentric section, and a stroke ring arranged so as to surround the eccentric section and, for each piston, a sliding shoe connected to the piston and abutting the stroke ring. An alternative design is also provided, in which an annular groove is provided on the radially outer peripheral surface of the stroke ring and a radially extending passageway is provided between the sliding shoe and the piston, which is particularly compact. The groove and the passage can be easily formed at low cost. Fuel can be guided through the grooves and passages with a relatively small flow resistance. Therefore, for example, no complicated hole is formed in the cylinder head of the radial piston pump. This additionally keeps the cost low.

A fuel pump device in which the fuel pump has a suction valve arranged on the piston is designed for the same purpose. By such means, the size and manufacturing costs of the fuel pump system are reduced.

Furthermore, it is proposed that at least the valve member of the suction valve is made of a ceramic material. Such a ceramic valve member can be formed relatively easily,
This has advantages with respect to valve dynamics. Furthermore, such valve members are resistant to wear, which improves the service life of fuel pump devices constructed in this way.

In a particularly advantageous further development of the fuel pump device according to the invention, the fuel pump device has an electronic control part for controlling the drive motor, which control part has a control part casing. And the control part casing is
It is fixed to the casing of the unit consisting of the fuel pump and the drive motor by at least one fixing means. For the main types of drive motors, an electronic controller is in any case necessary in order to prepare the necessary signals for the drive in the desired form. The electronics can be best pre-assembled by mounting them on separate control parts. In particular, during the pre-assembly, the assembly conditions required for the error-free functionality of the control electronics can be adhered to. The control part casing of the control part is then fixed to the casing of the unit consisting of the fuel pump and the drive motor. If this is done before the assembling to the internal combustion engine, the assembling work to the internal combustion engine becomes easy.

In this case, it is further advantageous if the fixing means penetrates the wall of the casing of the unit consisting of the fuel pump and the drive motor, the fixing means being relative to the casing of the unit consisting of the fuel pump and the drive motor. It is sealed by the sealing means. Since the fixing means penetrates the wall of the casing of the unit formed by the fuel pump and the drive motor, the control part casing can be fixed particularly reliably and stably. At the same time, the sealing means provided by the invention ensures that the fuel present in the casing does not flow out of the casing into the control part.

It is further advantageous if an electrical line from the control part to the drive motor is connected to the fixing means. Connecting the control electronics to the drive motor is easy. In this case, the line is, for example, cast in the fixing means, or welded or brazed to the fixing means, so that the casing of the control part casing and the unit consisting of the drive motor and the fuel pump. The sealability between and is guaranteed.

It is further advantageous if the degassing passage leads from the fastening means outwardly between the control part casing and the casing of the unit consisting of the fuel pump and the drive motor. is there. As a result, when fuel gas is generated and flows in the vicinity of the seal means or flows through the seal means, and exits from the inner chamber of the drive motor and the casing of the fuel pump and the fuel pump to reach the outside. Is isolated from sensitive control electronics,
It is released to the surroundings.

The assembly of the fuel pump device is such that the casing of the unit consisting of the fuel pump and the drive motor has at least two parts, which are liquid-tightly connected to one another and to one part. Is further facilitated by the fact that the fuel pump and the rotor connected to the drive shaft belong and the stator to the other part. Therefore, the two parts are independent of each other and can possibly be preassembled at different manufacturing locations. Nevertheless, final assembly is extremely easy.

The invention further relates to a fuel system for an internal combustion engine, in particular for direct injection, which is provided with a first fuel pump for pumping fuel to a fuel pump device, said fuel pump device comprising: And a fuel pump electrically connected to the fuel pump, a high-pressure region is provided, and the high-pressure region is pumped by the second fuel pump, and at least 1 Of the type in which two fuel injectors are connected.

In order to simplify the structure of the fuel system, securely and inexpensively assemble the components of the fuel system, and improve the efficiency of the fuel system, the second fuel pump is a radial piston pump, and the drive motor is And the second fuel pump form a unit with one common liquid-tight casing.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described in detail with reference to the drawings.

In FIG. 1, the overall fuel system for an internal combustion engine is shown at 10. The internal combustion engine is only partially shown in FIG. 1 and is designated by 12.

The fuel system 10 has a fuel tank 14, and the fuel is pumped from the fuel tank 14 by a fuel pump 16. The fuel pump 16 is driven by an electric drive motor 18. Fuel pump 16
Pumps fuel through the filter 19 to the fuel pump device 20. The fuel pump device 20 has a casing 22, and an electric drive motor 24 and a radial piston pump 26 are mounted in the casing 22. An electronic control part 28 is fixed to the casing 22. The exact configuration of the fuel pump device 20 will be described in detail later.

The fuel pump device 20 supplies fuel under high pressure to
It is fed under pressure to the fuel collection conduit 30 (rail) that belongs to the high pressure region. In the fuel collection conduit 30, the fuel is stored under high pressure. A plurality of fuel injection devices 32 are connected to the fuel collection conduit 30. These fuel injection devices 3
2 injects fuel directly into the corresponding combustion chamber 34 of the internal combustion engine 12. The pressure in the fuel collection conduit 30 is measured by the pressure sensor 3
Detected by 6. The pressure sensor 36 supplies a corresponding signal to the control and adjustment device 38. From this control / regulation device 38, a control line leads to an electric control part 28 of the fuel pump device 20 and to an electric drive motor 18 for driving the fuel pump 16.

The fuel pump device 20 is formed as follows (see FIG. 2). The casing 22 is made up of two parts, a left part 40 in FIG. 2 and a right part 42 in FIG. Left casing part 40
Are formed in a block shape and have a substantially cylindrical plate shape. Blind holes 45 are provided concentrically to the longitudinal axis 44 from the right side of FIG. 2 to the left casing part 40. The bag hole 45 has a plurality of bag holes 46, which are distributed in the circumferential direction and extend in the radial direction, and which are open toward the outside. The cylinder of the radial piston pump 26 is located in the bag hole 46. Only one such cylinder is shown in the cross-section plane of FIG. The radially extending blind holes 46 are each fluidly connected to the electric drive motor 24 by an opening 47. In this opening 47,
One mesh insert 49 is provided for each.

In the blind hole 45, two rolling bearings 48, 5 are provided.
0 is inserted. Due to these rolling bearings 48, 50, the drive shaft 52 is supported on the left casing part 40 with low friction. A cover ring 53 is fixed to the fixed portion of the right rolling bearing 50 toward the electric drive motor 24. This cover ring 53
The rolling bearing 50, the electric drive motor 24 during operation
Protects against particles generated by. Drive shaft 52
Has an eccentric section 54 located at the height of the blind hole 46 in the assembled position. A stroke ring 56 is fitted over the eccentric section 54. In the region of the cylinder, the outer peripheral surface of the travel ring 56 is chamfered flat.

A bush 58 is inserted into the radially extending bag hole 46 of the cylinder. A piston 60 is accommodated in the bush 58 so as to be slidable in the radial direction. A sliding shoe 62 is fixed to the radially inner end of the piston 60. The sliding shoe 62 is attached to the stroke ring 5 by a compression spring 64 supported by a bush 58.
Loaded towards 6. A consistent groove 66 is provided on the outer peripheral surface of the stroke ring 56, which is chamfered in a predetermined area. A hole 68 provided in the sliding shoe 62 and a hole 70 extending concentrically in the piston 60 are connected to the groove 66.

The radially outer region of the bore 70 provided in the piston 60 has a larger diameter than the radially inner region. A slanted transition surface (no reference number) is located at the transition between these two areas. The transition side is
It forms the valve seat for the valve ball 72 of the suction valve 74. The valve ball 72 is made of a ceramic material and is loaded on the valve seat by a compression spring (unsigned). Piston 6
A working chamber 78 is provided between 0 and the cylinder head 76 that closes the bag hole 46 outward in the radial direction. The working chamber 78 is connected via a pressure valve 80, which is embodied as a flat seat valve, to an outflow passage 82 provided in the left casing part 40. The outflow passage 82 further communicates with the fuel collection conduit 30.

Drive shaft 52 of radial piston pump 26
2 is directed to the right side of FIG.
Of the electric drive motor 24, forming the rotor shaft 84 of the rotor 86 of the electric drive motor 24. The rotor 86 is fixed to the rotor shaft 84 by screws 88, and is fixed to the rotor shaft 84 by a lock washer 90 so as not to rotate relative to each other. Rotor 8
6 has a cup shape. A magnet 92 is attached to the outer circumferential surface of the rotor 86 in the radial direction.

The right casing part 42 is likewise cup-shaped. The casing portion 42 is sealed to the left casing portion 40 via an O-ring 93. The coil 94 of the drive motor 24 is fixed to the radially inner peripheral surface of the casing portion 42. The inner chamber of the right casing portion 42 is connected to the first fuel pump 16 via an inflow portion (not shown).

On the right side of the casing part 42 on the right side of FIG. 2 is located the electrical control part 28. The control part 28 has a casing 96,
An electrical component 98 necessary for controlling the activation of the coil 94 of the electric drive motor 24 of the radial piston pump 26 is attached to the valve 6. The electrical component 98 is also activated and controlled by the control and adjustment device 38. The control portion casing 96 is fixed to the right casing portion 42 via a bolt 100.
The bolt is guided by two sleeves 102 and 104, and an O-ring 106 is press-fitted between the sleeves 102 and 104 at the insertion position. In this case, the lengths of the sleeves 102 and 104 are the O-ring 10
6 is selected to lie in the region of the casing part 42 on the right side. The inner chamber of the casing part 42 on the right is thereby closed in a liquid-tight manner.

Guided within the bolt 100 is a conductor 108 from the coil 94 to an electrical component 98. Conductor 108 is optionally welded or brazed to bolt 100. Between the control part casing 96 and the right casing part 42, from the bolt 100, a degassing passage 110 in the form of a groove on the outside of the casing part 42 extends radially outward. Through the degassing passage 110, during operation, the right casing portion 42
The gas arriving from through the O-ring 106 is moved away from the electrical component 98 and is directed radially outward.

During operation, the fuel is compressed by the first fuel pump 16 to about 4-6 bar. At this pressure, the fuel reaches the inner chamber of the casing part 42 on the right side. Through the electrical component 98, the electric drive motor 18 is rotated by the control and adjustment device 38. As a result, the drive shaft 52 is also rotated, the stroke ring 56 is rotated, and the piston 60 is reciprocated. The fuel flows through the inner chamber of the casing part 42 on the right side, in this case also cooling each of the components of the drive motor 24 and the output electronics 98, the opening 47, the groove 66 of the stroke ring 56 and the sliding shoe. Hole 68 provided in 62
And through the hole 70 provided in the piston 60 to reach the inside of the working chamber 78. Impurities are kept away from the work chamber 78 by the net 49 provided in the opening 47. Working room 78
From there, the fuel further reaches the fuel collection conduit 30 via the outflow passage 82.

The fuel pump device 20 is assembled as follows. First, the left casing part 40 is preassembled to the components of the radial piston pump 26. In this case, the rotor 86 of the electric drive motor 24 is
It is already fixed to the rotor shaft 84. At the same time, in some cases, in a separate assembly operation, the right casing part 4
2 is preassembled to the coil 94. Both the assembly of the control part casing 96 and the coupling of the coil 94 to the electrical component 98 of the control part casing 96 can take place here.

Next, final assembly is performed. In this final assembly, the right casing part 42 with coil 94
Is fitted over the rotor 86, and the left casing part 4
It is fixed at 0. In this way, a radial piston pump 26 for producing a very high pumping pressure, an electric drive motor 24 belonging to this radial piston pump 26 for producing a high rotational speed, and an electric drive An integrally assembled compact unit is formed having an electrical control portion 28 for controlling the activation of the motor 24.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a fuel system of an internal combustion engine having a fuel pump device and performing direct injection.

FIG. 2 is a diagram showing a partial cross-sectional view of the fuel pump device of FIG.

[Explanation of symbols]

10 fuel system, 12 internal combustion engine, 14 fuel tank, 16 fuel pump, 18 drive motor,
19 filter, 20 fuel pump device, 22 casing, 24 drive motor, 26 radial piston pump, 28 control part, 30 fuel collecting conduit,
32 fuel injection device, 34 combustion chamber, 36 pressure sensor, 38 control and adjustment device, 40 left casing part, 42 right casing part, 44 longitudinal axis, 45 blind hole, 46 blind hole, 47 opening, 48 bearing, 49 filter insert, 50 bearing, 52 drive shaft, 53 cover, 54 eccentric section, 56 stroke ring, 58 bush, 60 piston, 62 sliding shoe, 64 compression spring, 6
6 groove, 68, 70 hole, 72 valve ball, 74 suction valve, 76 cylinder head, 78 working chamber, 80
Pressure valve, 82 outflow passage, 84 roller shaft, 8
6 rotor, 90 lock washer, 92 magnet,
94 coil, 96 control part casing, 98
Component parts, 100 bolts, 102, 104 sleeves, 106 O-rings

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F04B 9/04 F04B 21/00 G 53/00 H 53/06 W 53/10 21/02 B 53/12 21/04 A 53/16 (72) Inventor Martin Kessler Germany Tiffenbronn Panorama Strasse 12/1 (72) Inventor Michael Hubel Germany Gerlingen Lorscher Wake 1 (72) Inventor Bernd Schroeder Germany Republic Esslingen Neuestrasse 14 F term (reference) 3H070 AA01 BB02 CC37 DD00 DD11 DD31 DD91 EE11 3H071 AA07 BB01 CC47 DD00 DD01 DD13 DD31 DD62 DD84 EE11 3H075 AA03 BB02 BB30 CC40 DA00 DA01 DA09 DB21 DB00 DB21 DB00 DB21 DB00

Claims (14)

[Claims] 1. A fuel pump arrangement (20) for a fuel system (10) of an internal combustion engine (12), in particular for direct injection.
And the fuel pump (26) and the fuel pump (2
Of the type having an electric drive motor (24) connected to 6), wherein the fuel pump is a radial piston pump (26) and the drive motor (24) and the fuel pump (26) But 1
Fuel pump arrangement for a fuel system of an internal combustion engine, characterized in that it forms a unit with two common liquid-tight casings (22). 2. The fuel pump (26) has a drive shaft (52) with at least one bearing (48, 50), which drive shaft (52) simultaneously drives a drive motor (24).
2. The fuel pump device according to claim 1, which forms the rotor shaft (84) of the. 3. A cover (53) which is preferably liquid-tight is provided, by means of which the bearing (50) is
3. The fuel pump device according to claim 2, which is protected from particles originating from the drive motor (24). 4. A fuel pump (26) and a drive motor (2)
4. The fuel pump device according to claim 1, wherein the internal chamber of the casing (22) of the unit consisting of 4) and 4) is flowed by fuel at least in the region of the drive motor. 5. A fuel pump (26) and a drive motor (2)
4) and the flow guide in the inner chamber of the casing (22) of the unit
4) through at least a predetermined region and then to the fuel pump (26), in the flow path between the drive motor (24) and the fuel pump (26), a filter device, 5. A fuel pumping device according to claim 4, in particular provided with a mesh (49). 6. The drive shaft (52) of the fuel pump (26) has an eccentric section (54), a stroke ring (56) arranged to surround the eccentric section (54) and each piston. For each (60), coupled to the piston (60),
A sliding shoe (62) is provided that abuts the travel ring (56), and a consistent groove (66) is provided on the radially outer peripheral surface of the travel ring (56) to provide the sliding shoe (62) and piston (62). 60) and a passage extending in the radial direction (68, 7)
0) is provided, The fuel pump device according to any one of claims 1 to 5. 7. The fuel pump (26) comprises a piston (6).
7. The fuel pump device according to claim 1, which has a suction valve (74) arranged at 0). 8. At least a valve member (7) of a suction valve (74).
8. The method according to claim 7, wherein 2) is made of a ceramic material.
The described fuel pump device. 9. An electronic control part (28) for controlling the drive motor (24), said control part (28) having a control part casing (96), said control part casing. (96) is a casing (22) of a unit including a fuel pump (26) and a drive motor (24).
Fuel pump device according to any one of the preceding claims, wherein the fuel pump device is fastened to at least one fastening means (100). 10. The fixing means (100) penetrates the wall of a casing (22) of a unit consisting of a fuel pump (26) and a drive motor (24),
Fuel pump arrangement according to claim 9, characterized in that the valve (0) is sealed to the casing (22) of the unit consisting of the fuel pump (26) and the drive motor (24) by sealing means (106). 11. The drive motor (2) from the control part (28).
11. A fuel pumping device according to claim 10, wherein an electrical line (108) leading to 4) is connected to a fixing means (100). 12. From the fixing means (100), advantageously
A degassing passage (110) leads outwardly between the control part casing (96) and the casing (22) of the unit consisting of the fuel pump (26) and the drive motor (24). Item 10. The fuel pump device according to item 10 or 11. 13. A fuel pump (26) and a drive motor (2)
4) has a casing (22) having at least two parts (40, 42), which parts (40, 42) are liquid-tightly connected to one another,
The fuel pump (26) and the rotor (86) coupled to the drive shaft (52) belong to one part (40), and the stator (94) belongs to the other part (42). The fuel pump device according to any one of claims 1 to 12, which is present. 14. Internal combustion engine (12), in particular for direct injection
Fuel system (10) for a first fuel pump (16) for pumping fuel to a fuel pump device (20)
And the fuel pump device (20) has a second fuel pump (26) and an electric drive motor (24) connected to the fuel pump (26),
A high pressure region (30) is provided, and the high pressure region (3
0) in which the second fuel pump (26) is pumped and at least one fuel injection device (32) is connected, the second fuel pump being a radial piston pump (26). Drive motor (24) and second fuel pump (2
6) A fuel system for an internal combustion engine (12), characterized in that it forms a unit with one common liquid-tight casing (22).