WO2005080799A1

WO2005080799A1 - Fuel pump, fuel feed device

Info

Publication number: WO2005080799A1
Application number: PCT/JP2005/002774
Authority: WO
Inventors: Toshifumi Noda; Shinya Nozaki; Daijo Ushiyama; Teruaki Ishikawa; Yukihiro Hayasaka
Original assignee: Bosch Corporation
Priority date: 2004-02-23
Filing date: 2005-02-22
Publication date: 2005-09-01
Also published as: JP2005233162A

Abstract

A fuel pump provided with a drive power transmitting mechanism based on a cylinder type magnet coupling device eliminates the possibility that a magnet adhesively attached to the outer peripheral surface of an inner yoke will scale off under the influence of the fuel. An inner yoke (56) having an inner magnet (561) adhesively attached to the outer peripheral surface thereof is disposed in a region outside a fuel chamber (54), which region is isolated from the fuel chamber (54) by a partition wall (58). An outer yoke (57) having an outer magnet (571) adhesively attached to the inner peripheral surface thereof is disposed in the fuel chamber (54) to which DME fuel is fed. The surface of contact between the inner peripheral surface of the outer yoke (57) disposed in the fuel chamber (54) and the outer magnet (571) adhesively attached to the inner peripheral surface of the outer yoke is subjected to the influence of DME fuel. However, when the rotary drive power is transmitted from the inner yoke (56) to rotate the outer yoke (57), the centrifugal force presses the outer magnet (571) against the inner peripheral surface of the outer yoke (57) for firmer contact therebetween.

Description

Specification

Fuel pump, fuel supply device

Technical field

[0001] The present invention relates to a fuel supply device for an engine, particularly a liquefied gas such as LP gas (hereinafter referred to as "high cetane number LP gas") to which DME (dimethyl ether) cetane improver is added. The present invention relates to a diesel engine fuel supply device.

Background art

[0002] As a countermeasure against air pollution by a diesel engine, attention has been paid to a method using DME (dimethyl ether) with a clean exhaust gas and high cetane number LP gas as a fuel instead of light oil. These fuels are liquefied gas fuels, unlike light oil, which is the conventional fuel. In other words, light oil is liquid at room temperature under atmospheric pressure, which has a lower boiling point than gas oil, whereas DME ゃ high cetane number LP gas has the property of becoming a gas at room temperature. Therefore, when liquefied gas fuel such as DME is used in a conventional diesel engine, the fuel supply of a diesel engine equipped with a fuel supply pump such as an injection pump or a supply pump that sends fuel to the fuel injection nozzle of the diesel engine is required. In the system, liquefied gas fuel will vaporize if the delivery pressure when delivering fuel from the fuel tank to the fuel supply pump is low. Therefore, in order to supply the liquefied gas fuel in a liquid state from the fuel tank to the fuel supply pump, the fuel supply pressure to the fuel supply pump needs to be higher than when light oil is fueled. In such a diesel engine fuel supply device, a general fuel pump such as a feed pump for delivering liquefied gas fuel from a fuel tank to a fuel supply pump includes a pump mechanism arranged in a liquefied gas fuel flow path, It has a driving force source such as an electric motor for driving the pump mechanism. For example, if the rotary shaft of the electric motor is directly connected to the pump mechanism, the fuel supply pressure of the liquefied gas fuel is set to be high for the above-described reason. There is a possibility that the liquefied gas fuel leaks from the liquefied gas fuel flow path to the electric motor side.

[0003] As an example of a conventional technique capable of solving such a problem, there is a technique in a fuel flow path. 2. Description of the Related Art There is known a fuel pump configured to transmit a driving force of a driving force source such as an electric motor to a pump mechanism to be disposed by a known cylinder-type magnet coupling device (for example, see Patent Document 1). . Since the magnet coupling device can transmit the driving force through the partition wall, it can be driven in a non-contact manner in a special atmosphere (vacuum, liquid, etc.), thereby preventing fuel leakage and reducing electric power. Driving power sources such as motors can be protected by fuel power.

Patent Document 1: Japanese Patent Application Laid-Open No. 2003-269275

Disclosure of the invention

Problems to be solved by the invention

[0005] However, in the above-mentioned conventional technology (for example, Patent Document 1), when the above-mentioned liquefied gas fuel is used as a fuel, a specific problem occurs depending on the properties of the liquefied gas fuel. In other words, in the inner yoke that is disposed together with the pump mechanism in the liquefied gas fuel flow path of the cylinder-type magnet coupling device, the effect of the liquefied gas fuel is caused by the bonding portion of the magnet bonded to the outer peripheral surface of the inner yoke. (Especially when DME is used as fuel, because DME also has the property of a solvent), the adhesive force of the adhesive bonding the magnet to the outer peripheral surface of the inner yoke decreases, and the inner yoke There is a risk that the magnet will peel off from the inner yoke due to the centrifugal force generated by rotation of the magnet. Further, the above-mentioned decrease in the adhesive strength of the adhesive tends to be observed in fuels containing gasoline or alcohol as a main component other than liquefied gas fuel such as DME.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a fuel pump having a driving force transmission mechanism using a cylinder-type magnet coupling device on an outer peripheral surface of an inner yoke. The purpose is to eliminate the possibility that the bonded magnet may be peeled off under the influence of fuel.

Means for solving the problem

[0007] In order to achieve the above object, a first aspect of the present invention provides a fuel chamber to which fuel is supplied from a fuel supply path, and an operation which is provided in the fuel chamber and transmitted by rotational driving force. A delivery device for delivering the fuel supplied into the fuel chamber to the fuel delivery channel; and a cylinder-type magnet for transmitting the rotational driving force of the rotary drive source to the delivery device. A fuel pump having a force pulling device, wherein the cylinder type magnet force pulling device has an inner magnet fixed to an outer peripheral surface of an inner yoke supported by the outside of the fuel chamber. An outer magnet is fixed to the inner peripheral surface of the outer yoke concentrically with the axis of the inner yoke via an adhesive, and the inner yoke is rotated by the rotational driving force of the rotational driving force source. A rotary drive force of the rotary drive power source is transmitted to the delivery device via the outer yoke connected to the inner yoke by magnetic force. It is.

[0008] In a known cylinder-type magnet coupling device, an inner magnet is fixed to an outer peripheral surface of an inner yoke (inner ring) rotatably supported by an adhesive or the like.

An outer yoke (outer ring) is rotatably supported on the outer side of the inner yoke. An outer magnet is fixed to the inner peripheral surface of the outer yoke, and the inner yoke and the outer yoke are disposed at positions where the outer magnet faces the outside of the inner magnet with the partition wall interposed therebetween. The inner yoke and the outer yoke can transmit the rotational driving force to each other in a non-contact manner by the inner magnet and the outer magnet being engaged with each other so as to transmit the rotation in a non-contact manner by a magnetic force across the partition wall. As described above, the inner magnet and the outer magnet are usually disposed on the outer peripheral surface of the inner yoke and the inner peripheral surface of the outer yoke with an adhesive therebetween. The inner yoke has an inner magnet adhered to its outer peripheral surface.When the inner yoke rotates, the inner magnet is separated from the outer peripheral surface of the inner yoke by centrifugal force generated by the rotation, that is, the direction in which the inner yoke tends to peel off. Force is applied. On the other hand, since the outer yoke has an outer magnet adhered to its inner peripheral surface, when the outer yoke rotates, the outer magnet is pressed against the inner peripheral surface of the outer yoke by centrifugal force generated by the rotation. In other words, a force in the direction of trying to adhere more firmly acts.

Therefore, an inner yoke having an inner magnet fixed to the outer peripheral surface is disposed outside the fuel chamber of the fuel pump, and an outer yoke having the outer magnet bonded to the inner peripheral surface is disposed inside the fuel chamber to which fuel is supplied. These components are arranged to form a cylinder type magnetic coupling device. In other words, the inner yoke, in which the force in the direction in which the magnet tends to peel off from the outer peripheral surface due to centrifugal force, is arranged outside the fuel chamber that is not affected by fuel, and the magnet is pressed against the inner peripheral surface by centrifugal force. The cylinder-type magnet coupling device is constructed by arranging an outer yoke in which a force in a direction of trying to adhere more firmly acts in a fuel chamber to which fuel is supplied. According to it

The fuel adhered to the magnet bonded to the outer surface of the inner yoke was affected by the fuel, the adhesive strength of the adhesive bonding the magnet to the outer surface of the inner yoke was reduced, and the magnet was peeled from the inner yoke. The effect of being able to eliminate the possibility of falling is obtained.

In addition, the inner yoke surface of the outer yoke disposed in the fuel chamber and the bonding surface of the outer magnet bonded to the inner yoke surface are affected by the fuel, but the rotational driving force is applied from the inner yoke. When the outer yoke rotates and is transmitted, the outer magnet is pressed against the inner peripheral surface of the outer yoke by centrifugal force and tries to adhere more firmly. There is almost no risk of peeling off from the surface.

[0010] A second aspect of the present invention is the fuel pump according to the first aspect, wherein the fuel is DME (dimethyl ether).

Among the liquefied gas fuels, especially when DME is used as fuel, it is considered that DME also has a property as a solvent, and therefore has a large effect on the adhesive. Therefore, according to the fuel pump shown in the second aspect of the present invention, it is possible to more effectively obtain the operation and effect according to the invention described in the first aspect.

[0011] A third aspect of the present invention is a fuel supply device for an engine including the fuel pump according to the first or second aspect described above.

According to the fuel supply device for an engine shown in the third aspect of the present invention, the fuel supply device for the engine can obtain the effect of the invention described in the first aspect or the second aspect described above. it can.

[0012] A fourth aspect of the present invention is directed to a fuel tank filled with fuel, a fuel supply pump for pressurizing and delivering the fuel to a fuel injection nozzle of a diesel engine, and a fuel tank for storing the fuel in the fuel tank. A fuel supply device for a diesel engine, comprising: a feed pump that feeds the fuel to a fuel supply pump; wherein the feed pump is the fuel pump according to the first or second aspect described above. This is a diesel engine fuel supply system. In a fuel supply device for a diesel engine, a feed pump that supplies fuel from a fuel tank to a fuel supply pump is in a state where fuel is always supplied from the fuel tank, and therefore, only when the fuel supply device is operating. Even when the fuel supply device is stopped, the inside is filled with fuel. As described above, in the fuel supply device for a diesel engine, the feed pump in which the fuel is always filled inside is the fuel pump shown in the first embodiment or the second embodiment described above, so that the fuel pump can be more effectively used. The operational effect according to the invention described in the first or second aspect can be obtained.

[0014] In a fuel pump provided with a driving force transmission mechanism using a cylinder-type magnet coupling device, it is possible to eliminate the possibility that the magnet adhered to the outer peripheral surface of the inner yoke is peeled off by the influence of fuel. it can.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

First, a schematic configuration of a DME fuel supply device as a “diesel engine fuel supply device” according to the present invention will be described. Typical examples of liquefied gas fuels as "fuel" include DME and high cetane number LP gas with a cetane number of about 40 to 55, preferably 50 or more (LP gas added with a cetane number improver). . In the embodiment described below, a case where DME, which is a liquefied gas fuel, is used as “fuel” will be described. When a high cetane number LP gas is used, known nitrate esters, nitrite esters, and organic peroxides are used as the cetane number improver. Specific examples of the cetane number improver include DTBP (D tertiary butyl peroxide) or 2HEN (2-Ethylhexylnitrate). In addition, since LP gas has low lubricity as compared with light oil, it is desirable to add a known alkyl ester as a lubricity improver.

FIG. 1 is a system configuration diagram showing a schematic configuration of a DME fuel supply device for a diesel engine.

The injection pump 1 includes the same number of injection pump elements 2 as the number of cylinders 31 included in the diesel engine 200. The feed pump 5 as the “fuel pump” according to the present invention pressurizes the DME fuel as the “fuel” stored in the fuel tank 4 to a predetermined pressure and sends it to the feed pipe 52. Sent to feed pipe 52 The DME fuel is filtered by the filter 51 and sent to the injection pump 1 via the three-way solenoid valve 71. The DME fuel pressurized from the fuel tank 4 to a predetermined pressure by the feed pump 5 and sent out is charged into the cam chamber 15 and the oil reservoir 11 defined, and the DME fuel filled in the oil reservoir 11 is discharged. A predetermined amount of pressure is fed from each injection pump element 2 of the injection pump 1 via the injection pipe 3 to the fuel injection nozzle 32 provided in each cylinder 31 of the diesel engine 200 at a predetermined timing. You. DME fuel overflowing from the oil reservoir 11 is returned to the fuel tank 4 via the overflow fuel pipe 8, the check valve 91, the pipe 92, and the cooler 41. The DME fuel overflowing from each fuel injection nozzle 32 is returned to the fuel tank 4 via the nozzle return pipe 9, the check valve 91, the pipe 92, and the cooler 41. Further, when the diesel engine 200 is stopped, the DME fuel supply device 100 collects the DME fuel remaining in the oil reservoir 11, the overflow fuel pipe 8, and the nozzle return pipe 9 in the injection pump 1 into the fuel tank 4. Aspirator 7, a three-way solenoid valve 71, and a two-way solenoid valve 72.

Next, the structure of the feed pump 5 as the “fuel pump” according to the present invention will be described. FIG. 2 is a sectional view of the feed pump 5.

In the DME fuel supply device 100, a feed pump 5 for supplying DME fuel from the fuel tank 4 to the injection pump 1 is supplied from the fuel tank 4 to the fuel chamber 54 via a pipe 42 as a "fuel supply path". The DME fuel is delivered to a pipe 53 as a “fuel delivery path” by a delivery device 541 provided in the fuel chamber 54. Since the DME fuel is always supplied from the fuel tank 4 in the fuel chamber 54, the fuel is supplied not only when the DME fuel supply device 100 is operating but also when the DME fuel supply device 100 is stopped. The chamber 54 is filled with DME fuel. The feed pump 5 includes a cylinder-type magnet coupling device MC that transmits the rotational driving force of the motor 55 as a rotational driving force source to the sending device 541. The cylinder-type magnet coupling device MC has an inner yoke 56, an outer yoke 57, an inner magnet 561, an outer magnet 571, and a partition 58 formed between the inner yoke 56 and the outer yoke 57. The outer yoke 57 is disposed in the fuel chamber 54 to which DME fuel is supplied from the fuel tank 4 and has a driven shaft 542. Fixed to. The driven shaft 542 is pivotally supported by a recess 581 formed in the partition wall 58 in a state in which the driven shaft 542 is engaged with the delivery device 541 so as to be able to transmit rotation.

An outer magnet 571 is fixed to the inner peripheral surface of the outer yoke 57 by bonding with an adhesive. The inner yoke 56 is disposed outside the fuel chamber 54 separated from the fuel chamber 54 by a partition wall 58, and is fixed to and supported by a rotating shaft 551 (drive shaft) of a motor 55. The rotation shaft 551 and the driven shaft 542 of the motor 55 are arranged on concentric axes. An inner magnet 561 is adhered and fixed to the outer peripheral surface of the inner yoke 56 with an adhesive. The inner yoke 56 and the outer yoke 57 are disposed at positions where the outer magnet 571 faces the outside of the inner magnet 561 with the partition wall 58 interposed therebetween as shown in the figure. In the feed pump 5 having such a configuration, the inner yoke 56 is rotated by the rotational driving force of the motor 55, and the inner magnet 561 and the outer magnet 571 are engaged with each other via the partition wall 58 so that rotation can be transmitted by magnetic force. Thus, the rotation of the inner yoke 56 is transmitted to the outer yoke 57, and the rotation of the outer yoke 57 is transmitted to the delivery device 541 via the driven shaft 541.

As described above, the inner yoke 56 with the inner magnet 561 bonded to the outer peripheral surface is disposed outside the fuel chamber 54 separated from the fuel chamber 54 by the partition wall 58, and the outer magnet 571 is disposed on the inner peripheral surface. The bonded outer yoke 57 is disposed in the fuel chamber 54 to which the DME fuel is supplied. As a result, the bonding portion of the inner magnet 561 bonded to the outer peripheral surface of the inner yoke 56 is affected by the DME fuel, which also has a property as a solvent, and the inner magnet 561 is bonded to the outer peripheral surface of the inner yoke 56. It is possible to eliminate the possibility that the adhesive force of the adhesive is reduced and the inner magnet 561 is peeled off from the inner yoke 56. In addition, the inner peripheral surface of the outer yoke 57 disposed in the fuel chamber 54 and the bonding surface of the outer magnet 571 bonded to the inner peripheral surface have a force that is affected by the DME fuel. When the outer yoke 57 rotates when the driving force is transmitted from the outer yoke 57, the centrifugal force causes the outer magnet 571 to be pressed against the inner peripheral surface of the outer yoke 57 and try to adhere more firmly. There is almost no possibility that the outer magnet 571 will peel off from the inner peripheral surface of the outer yoke 57.

[0020] Thus, in the feed pump 5 (fuel pump) provided with the driving force transmission mechanism by the cylinder-type magnet coupling device MC, the feed pump 5 (fuel pump) is attached to the outer peripheral surface of the inner yoke 56. It is possible to eliminate the possibility that the inner magnet 561 that has been peeled off due to the influence of the DME fuel. In addition, other than the liquefied gas fuel typified by DME as described above, a fuel containing gasoline or alcohol as a main component may affect the adhesive strength of the adhesive for bonding the magnet. The functions and effects of the present invention can be obtained in all fuel pumps for fuel.

The present invention is not limited to the above embodiments, and various modifications are possible within the scope of the invention described in the claims, which are also included in the scope of the present invention. It goes without saying that there is.

Industrial applicability

[0022] The present invention relates to a fuel supply device for an engine, particularly a liquefied gas such as LP gas (hereinafter referred to as "high cetane number LP gas") to which DME (dimethyl ether) / a cetane improver is added. It can be used in a fuel supply device for a diesel engine.

Brief Description of Drawings

FIG. 2 is a sectional view of a feed pump.

Claims

The scope of the claims

[1] A fuel chamber to which fuel is supplied from a fuel supply path, and a fuel chamber which is disposed in the fuel chamber and operates by transmitting a rotational driving force to supply fuel supplied from the fuel supply path into the fuel chamber. A fuel pump comprising: a delivery device that delivers to a fuel delivery path; and a cylinder-type magnet coupling device that transmits a rotational driving force of a rotational driving force source to the delivery device, wherein the cylinder-type magnet coupling device includes: An inner magnet is fixed to an outer peripheral surface of an inner yoke pivotally supported outside the fuel chamber, and an outer magnet is bonded to an inner peripheral surface of an outer yoke pivotally supported in the fuel chamber concentrically with the axis of the inner yoke. The inner yoke is rotated by the rotational driving force of the rotational driving force source, and is connected to the inner yoke by magnetic force. Through the rotational driving force of the rotary driving power source and has a configuration to be transmitted to said delivery device, the fuel pump characterized in that.

[2] The fuel pump according to claim 1, wherein the fuel is DME (dimethyl ether).

[3] A fuel supply device for an engine, comprising the fuel pump according to claim 1 or 2.

[4] a fuel tank filled with fuel, a fuel supply pump for pressurizing and delivering the fuel to a fuel injection nozzle of a diesel engine, and a feed pump for delivering the fuel in the fuel tank to the fuel supply pump. 3. A fuel supply device for a diesel engine according to claim 1, wherein the feed pump is the fuel pump according to claim 1 or 2.