WO2015169478A1

WO2015169478A1 - Fuel pump and method for operating same

Info

Publication number: WO2015169478A1
Application number: PCT/EP2015/054811
Authority: WO
Inventors: Siamend Flo; Frank Nitsche; Jurij ARTAMONOV; Walter Maeurer; Andrea Krusch; Thorsten Allgeier; Juergen Koreck; Andreas PLISCH
Original assignee: Robert Bosch Gmbh
Priority date: 2014-05-08
Filing date: 2015-03-09
Publication date: 2015-11-12
Also published as: JP6381786B2; CN106460748A; JP2017515049A; CN106460748B; DE102014208631A1

Abstract

The invention relates to a fuel pump which comprises a piston (2), an actuator (3) for actuation of the piston (2), a restoring element (4) for restoring the piston (2) to a starting position, a first inlet valve (5), an outlet valve (6), and a conveying chamber (7), characterised by an antechamber (8), and a second inlet valve (9) which closes or releases a connection between the conveying chamber and the antechamber. The invention further relates to a method for conveying fuel in two stages by means of a fuel pump (1) according to the invention.

Description

Description title

Fuel pump and method of operating the same prior art

The present invention relates to a fuel pump for supplying fuel to a motor vehicle such as e.g. Motorcycle, motorboat, or other small engine applications such as Chainsaws, and a method of operating such a fuel pump. Furthermore, the present invention relates to a fuel tank comprising such a fuel pump.

Such a fuel pump is known for example from GB 2478876 B. This is a fuel pump, in particular a magnetic piston pump, which has a piston, an actuator for actuating the piston, a return element for returning the piston into a

Starting position, an inlet valve, a delivery chamber and an outlet valve. By actuating the piston, fuel is sucked into the delivery chamber via the inlet valve in the intake phase. In the delivery phase, the fuel is conveyed out of the delivery chamber via the outlet valve. Due to temperature load, the fuel can outgas at low suction pressure at the inlet valve, whereby the delivery chamber largely with

Fuel vapor is filled. This can affect the degree of delivery and the function of the pump considerably up to total failure.

Disclosure of the invention

The fuel pump according to the invention with the features of claim 1 has the opposite over the advantage that a minimum negative pressure in the intake phase can be reduced, whereby a fuel outgassing can be prevented. This is inventively achieved in that the fuel is pre-conveyed into an anteroom, wherein the fuel under pressure is set before the fuel via a second inlet valve in the

Delivery room passes. Here, the fuel pump comprises a piston, an actuator for actuating the piston, a return element for returning the piston to an initial position, a first inlet valve, an outlet valve, and a delivery chamber. According to the invention, an antechamber and a second

Intake valve provided, which closes or releases a connection between the delivery chamber and the antechamber. Thus, according to the invention, by using a second inlet valve which is arranged upstream of the first inlet valve, improved fuel delivery can be achieved.

The dependent claims show preferred developments of the invention.

Preferably, the piston can separate the delivery chamber from the vestibule. Thus, a two-stage delivery of the fuel by means of a single

Fuel pump and a single piston can be ensured. This can lead to cost and space savings, which is particularly important in motorcycles or other small devices with little available space. Preferably, the delivery chamber and the antechamber in a common

Cylinder component may be arranged. Thus, an even more compact and space-saving design can be made possible.

According to yet another alternative embodiment of the present invention, the piston may preferably have a cavity into which the vestibule extends. For one thing, the presence of a

Cavity in the piston lead to a reduction in material, which in turn has a cost reduction without affecting the strength or function of the piston. On the other hand, the use of the cavity of the piston as a vestibule allows a compact construction. Preferably, the

Cavity of the piston the whole vestibule.

To connect the anteroom and the pump room

To provide, preferably, a through hole may be formed in the piston, wherein the second inlet valve closes or releases the through hole. Furthermore, a compact design of the fuel pump arrangement is possible by the arrangement of the passage opening in the piston. More preferably, the passage opening in the piston can open on the delivery chamber. Thus, a short and direct promotion of the fuel from the vestibule into the delivery chamber is possible. As a result, resistance losses due to, for example, a longer flow path can be avoided.

Further preferably, the first intake valve, the second intake valve and the exhaust valve may be arranged in a line. This is understood to mean that the first intake valve, the second intake valve and the exhaust valve are arranged as components in series on a common line. Thus, a

Conveying the fuel as possible on a flow line, resulting in a reduction of losses due to e.g. a flow path can lead with deflections. Alternatively, the second intake valve and the exhaust valve may be arranged in a common plane. This results in a more compact construction of the fuel pump.

Preferably, a maximum release cross section of the first

Inlet valve be greater than a maximum release cross-section of the second inlet valve. This can reduce the suction losses and thus the minimum negative pressure.

More preferably, the antechamber may have a first dead volume and the delivery chamber may have a second dead volume, wherein the first dead volume and the second dead volume are substantially equal. When at

Delivery chamber and vestibule dead volume is present, the two dead volume should preferably be equal or approximately equal. Thus, a better and faster promotion between the pump room and anteroom can be done.

Furthermore, the present invention relates to a fuel tank having a fuel pump according to the invention, which is arranged in the fuel tank. Furthermore, the invention relates to a motor vehicle, in particular a motorcycle, or another gasoline-powered device such as a Gartenbzw. Domestic appliance comprising a fuel pump according to the invention. Furthermore, the invention relates to a method for two-stage conveying of

Fuel by means of a fuel pump according to the invention with the features of claim 12. In this case, the method according to the invention comprises the suction of fuel via the first inlet valve into the antechamber, pressurizing the fuel in the antechamber, conveying the pressurized fuel from the antechamber over the second intake valve into the delivery chamber, pressurizing the fuel in the delivery chamber, and delivering the pressurized fuel via the discharge valve from the delivery chamber. Thus, those through the above

described advantages obtained here also ensured fuel pump.

More preferably, the suction in the vestibule can take place simultaneously with the pressurization of the fuel located in the delivery chamber. Thus, a timely two-stage delivery of the fuel is possible.

Furthermore, the suction process can preferably take place on a rear side of the piston and the conveying of the fuel located in the delivery chamber can take place on an end face of the piston. Thereby, a two-stage delivery of the fuel can be ensured by means of only a single fuel pump in a compact design.

Brief description of the drawings

Hereinafter, two embodiments of the invention below

Reference to the accompanying drawings described in detail, wherein identical or functionally identical parts are each denoted by the same reference numerals. In the drawing is:

1 is a simplified sectional view of a fuel pump according to a first embodiment of the present invention,

FIG. 2 shows a schematic, highly simplified sectional view of a part of the fuel pump according to the first exemplary embodiment for illustrating the principle of a suction and delivery phase, Figure 3 is a schematic, greatly simplified sectional view of the in

Figure 2 shown part of the fuel pump for schematic representation of a prefeed phase, and

Figure 4 is a highly simplified, schematic sectional view of a portion of a fuel pump according to a second embodiment of the present invention.

Embodiments of the invention

Hereinafter, a fuel pump 1 according to a first preferred embodiment of the invention will be described in detail with reference to FIG.

As can be seen from Figure 1, the fuel pump 1 according to the invention is in the form of a magnetic piston pump and accordingly has a piston 2, a solenoid coil 3 as an actuator for actuating the piston 2 and a spring element as a return element 4 for returning the piston 2 to an initial position , Furthermore, the fuel pump 1 according to the invention comprises a first intake valve 5, an exhaust valve 6, a delivery chamber 7, an antechamber 8 and a second intake valve 9.

The piston 2, which is cylindrical and in which a passage opening 21 is formed, separates the delivery chamber 7 from the antechamber 8, wherein the delivery chamber 7 and the antechamber 8 are arranged in a common cylinder component 10. The piston 2 is also arranged in the cylinder component 10. Furthermore, the piston 2 has a cavity 20, which is cylindrical and in which the vestibule 8 extends. Furthermore, the vestibule 8 is in communication with the passage opening 21.

Via the first inlet valve 5, the antechamber 8 is further connected to an inlet 11, wherein the inlet 11 is in turn connected to e.g. with a fuel tank or with a fuel line (not shown) is in communication. The first inlet valve 5, which is arranged on a rear side 22 of the piston, is a

Reed valve. Of course, other forms of valves, e.g.

Diaphragm valves, check valves, etc. conceivable. The second inlet valve 9, which is also a platelet valve, for example, closes off or releases the through-opening 21 between the delivery chamber 7 and the antechamber 8, the through-opening 21 discharging at the delivery chamber 7. Furthermore, the second inlet valve 9 is arranged on an end face 23 of the piston 2. As shown in FIG. 1, a maximum release cross section 50 of the first intake valve 5 is greater than a maximum release cross section 90 of the second intake valve 9.

The exhaust valve 6 is arranged so that the delivery space 7 is formed between the exhaust valve 6 and the second intake valve 9. Furthermore, the outlet valve 6 is formed as a platelet valve.

Further, the first intake valve 5, the second intake valve 9 and the

Outlet valve 6 arranged in series on a common center line M.

Hereinafter, the method for operating the fuel pump 1 will be described in detail with reference to FIGS. 2 and 3.

To explain the method according to the invention, the general function of the fuel pump 1 with respect to the interaction of the actuator 4 with the piston 5 will first be described.

When the actuator 4 or the magnetic coil of the fuel pump 1 is energized, the piston 2 moves through the generated magnetic field in a first direction (bold arrow R in Figure 3), wherein the return element. 4

is compressed. If now the energization of the actuator 4 is turned off, the piston 2 is pushed by the movement of the return element 4 in a second direction, opposite to the first direction

(bold arrow L in Figure 2).

FIG. 2 illustrates an intake and a delivery phase of the method according to the invention, wherein the piston 2 is moved by the return element 4 in the second direction, which is indicated by the bold arrow L. Thereby opening the first intake valve 5 and fuel is e.g. from a fuel tank, but not shown, over the first one

Inlet valve 5 is sucked into the antechamber 8 (arrow A). It should be noted that the majority of the amount of fuel sucked into the cavity 20 of the piston 2 passes (arrows B), in which the vestibule 8 extends. Simultaneously with the suction of fuel via the first inlet valve 5 in the antechamber 8, fuel, which is already in the delivery chamber 7, set by the movement of the piston 2 in the second direction under pressure, the second

Inlet valve 9 closes. From a certain pressure level in the delivery chamber 7 opens the exhaust valve 6 and the pressurized fuel is conveyed via the exhaust valve 6 from the delivery chamber 7 to the internal combustion engine (not shown) (arrows C in Figure 2). FIG. 3 shows a prefeeding phase of the method according to the invention, wherein the piston 2 is moved by the actuator 3 in the first direction, which is indicated by the bold arrow R. By the movement of the piston 2, the first inlet valve 5 closes and the fuel located in the antechamber 8 is pressurized. From a certain

Pressure level in the antechamber 8 opens the second inlet valve 9. Thus, the in

Anteroom 8 pressurized fuel from the antechamber 8 via the second inlet valve 9 in the delivery chamber 7 pre-conveyed (arrow D).

Subsequently, the suction and delivery phase and a new stroke of the fuel pump 1 can now take place.

Hereinafter, a fuel pump 1 according to a second preferred embodiment of the invention will be described with reference to FIG. 4, showing the fuel pump 1 in the intake phase. In the intake phase, the first intake valve 5 and the exhaust valve 6 are open and the second intake valve 9 is closed.

The second embodiment differs fundamentally from the first embodiment in that the second inlet valve 9 and the

Exhaust valve 6 are arranged in a common plane E. Here, the piston 2, in contrast to the first embodiment no

Through opening, wherein the connection of the vestibule 8 with the

Delivery chamber 7 is provided via a line 1 2. The connection via the line 12 is closed or released by the second inlet valve 9. Furthermore, the piston 2 is formed such that the fuel pump 1 operates according to the method described above. The valves of this

Embodiment are also designed as ball check valves. It should be noted that the above-described embodiments are for the purpose of understanding the present invention and should not be considered as limiting in that respect. For example, a disc instead of a piston is also conceivable.

The fuel pump 1 according to the invention and the method according to the invention for operating the same thus leads to a compact solution to the problem of outgassing of fuel during intake, wherein a two-stage delivery of the fuel takes place, but without the need for a second

Fuel pump. Thus, space and costs can be saved. Furthermore, the suction at the back of the piston 2 results in a reduction of the minimum negative pressure, since the suction takes place at a lower speed and leads to an even more compact design of the

Fuel pump.

By the fuel pump 1 according to the invention and the inventive method, a better function of an internal combustion engine of a vehicle can be further ensured.

Claims

claims

1 . Fuel pump comprising:

a piston (2),

an actuator (3) for actuating the piston (2),

- A return element (4) for returning the piston (2) in one

Starting position

a first inlet valve (5),

- An outlet valve (6), and

- A conveying space (7), characterized by:

- An anteroom (8), and

- A second inlet valve (9), which closes or releases a connection between the delivery chamber (7) and the antechamber (8).

2. Fuel pump according to one of the preceding claims, characterized

in that the piston (2) separates the delivery chamber (7) from the antechamber (8).

3. Fuel pump according to one of the preceding claims, characterized

in that the delivery chamber (7) and the antechamber (8) are arranged in a common cylinder component (10).

4. Fuel pump according to one of the preceding claims, characterized

characterized in that the piston (2) has a cavity (20) into which the antechamber (8) extends.

5. Fuel pump according to one of the preceding claims, characterized

in that a through-opening (21) is formed in the piston (2), wherein the second inlet valve (9) closes or releases the through-opening (21).

6. Fuel pump according to claim 5, characterized in that the

Through opening (21) at the delivery chamber (7) opens. Fuel pump according to one of the preceding claims, characterized in that the first inlet valve (5), the second inlet valve (9) and the outlet valve (6) are arranged on a line (M).

Fuel pump according to one of claims 1 to 4, characterized

in that the second inlet valve (9) and the outlet valve (6) are arranged in a common plane (E).

Fuel pump according to one of the preceding claims, characterized in that a maximum release cross section of the first intake valve (5) is greater than a maximum release cross section of the second intake valve (9).

Fuel pump according to one of the preceding claims, characterized in that the antechamber (8) has a first dead volume and the delivery chamber (7) has a second dead volume, wherein the first dead volume and the second dead volume are substantially equal.

Motor vehicle comprising a fuel pump (1) according to one of the preceding claims.

12. A method for two-stage delivery of fuel by means of a

A fuel pump (1) having a piston (2), a first inlet valve (5), an outlet valve (6), a delivery chamber (7), an antechamber (8) and a second inlet valve (9), comprising the steps of:

Sucking fuel via the first inlet valve (5) into the antechamber (8),

Pressurizing the fuel located in the antechamber (8), conveying the pressurized fuel from the antechamber (8) via the second intake valve (9) into the delivery chamber (7),

- pressurizing the fuel located in the delivery chamber (7), and

- Delivering the pressurized fuel via the outlet valve (6) from the delivery chamber (7).

13. The method according to claim 12, characterized in that the

Suction in the antechamber (8) takes place simultaneously with the pressurization of the fuel in the delivery chamber (7). 14. The method according to claim 13, characterized in that the

Suction process takes place on a rear side (22) of the piston (2) and the conveying of the fuel located in the delivery chamber (7) takes place on an end face (23) of the piston (2).