JP2008014315A - Transfer pump with several pistons - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means supplying a sufficient quantity of fuel without causing operational problems even for large cylinder capacity. <P>SOLUTION: A transfer pump has a pump unit having the combination of a piston (1a) and a bellows (4a) operated by a cam (2a) and a pump unit having the combination of a piston (1b) and a bellows (4b) operated by a cam (2b). The quantities of fuel entering chambers (5a, 5b) with expansion and contraction of the bellows (4a, 4b) are determined by one flow control solenoid valve (8) which is controlled upstream by the control computer of an engine. The respective pump units are supplied with fuel through supply paths (6a, 6b) which have a common end and are bifurcated in the middle and the fuel in a high pressure condition is discharged through a common discharge path (10). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

An object of the present invention is to provide a so-called transfer-type pump having a movable part, that is, a transfer pump that supplies automobile fuel in a pressurized state.
Here, the movable part operates by the reciprocating motion of the piston, and supplies fuel in a state where pressure is applied.

  It is known to supply high-pressure fuel to an engine fuel injector using a hydraulic pump with a single piston, a so-called mono-piston pump.

  This type of pump is also described in U.S. Pat. No. 1,696,825, December 25, 1928, as well as patent application 06/02594, filed March 24, 2006 by the applicant.

  However, it is clear that when the cylinder volume is large, the flow rate provided by the monopiston pump is insufficient.

In fact, it is clear that there is a practical upper limit to the cylinder volume of a mono-piston pump, which limit is slightly greater than approximately 1 cs per revolution.
US Pat. No. 1,696,825

In order to increase the cylinder volume, it is necessary to lengthen the stroke of the piston or increase the diameter of the piston.
When the stroke is lengthened, the acceleration is considerably increased. When the diameter is increased, the stress in contact with the cam that drives the piston becomes too large.

  Therefore, it has been proposed to arrange two mono-piston pumps, which also requires electronic control means to be duplicated, which is suitable as a prototype, but economically for very large-scale mass production. Not suitable (2000 monopiston pumps and 2000 electronic controls are required for 1000 engines per day).

  These electronic control means are usually solenoid valves controlled by an engine control computer.

The transfer pump according to the present invention is a metal bellows type transfer pump that is alternately filled with a high-pressure hydraulic fluid by a movable pump component or is emptied. The pump comprises at least two pump units (bellows and piston), which are fueled by a single supply channel common to at least two units. Is provided.
The present invention can further include all or part of the following elements a to e.
a. The discharge path is common to the pump unit.
b. The pump comprises two pistons, each piston being operated by a cam, the two cams being supported in parallel by a camshaft and being offset by 60 °.
c. The pump includes n pistons, each piston is operated by a cam, and the n cams are supported parallel to each other by a camshaft and are offset in angle.
d. The pump includes a single piston and at least two pistons arranged radially about the cam.
e. The pump comprises two pistons arranged in a V shape at 60 ° to each other.

First,
The movable pump part is a transfer pump with a bellows (4) that is alternately filled with high-pressure hydraulic fluid or emptied by a piston (1) operated by a cam (2),
The movable pump component is a transfer pump of the type that is a bellows (4) that is alternately filled or emptied with high pressure hydraulic fluid by a piston (1) operated by a cam (2),
The amount of fuel entering the chamber (5) by expansion and contraction of the bellows (4) is determined upstream by a flow control solenoid valve (8) controlled by the engine control computer,
The transfer pump includes at least two pump units (piston 1 / bellows 4),
Fuel is supplied to each pump unit via a single supply path (6) common to each pump unit in which a flow control solenoid valve (8) is arranged upstream,
Moreover, each pump unit is provided with the single discharge path (10) common or dedicated to each pump unit, The transfer pump characterized by the above-mentioned.
Second,
Pump according to claim 1, characterized in that the piston (1) is operated by at least one cam (2) of a dedicated monolobe or multilobe.
Third,
Plural pistons (1a, 1b) for expanding and contracting bellows (4a, 4b, ..., 4n) disposed in chambers (5a, 5b, ..., 5n) connected to a common supply path (6) 2. The pump according to claim 2, wherein the pump is provided.
Fourth,
Pump according to claim 3, characterized in that the chambers (5a, 5b, ..., 5n) are connected to a common discharge channel (10).
Fifth,
The pistons (1a, 1b, ..., 1n) are respectively operated by monolobe or multilobe cams (2a, 2b, ..., 2n) arranged parallel to the camshaft (3). The pump according to any one of the first to fourth aspects.
Sixth,
The pump according to the third aspect, wherein each of the chambers (5a, 5b, ..., 5n) is connected to a dedicated discharge path.
Seventh,
The pistons (1a, 1b, ..., 1n) are operated by a single cam (2);
The pump according to any one of the first to fourth aspects, wherein the pistons are arranged radially about the cam (2).

As a non-limiting example, and to facilitate understanding of the present invention, it is illustrated in the accompanying drawings.
FIG. 1 is a schematic diagram of a first embodiment of the present invention.
FIG. 2 is a modification of FIG.
FIG. 3 is a perspective view illustrating the pump according to FIG.
FIG. 4 is a schematic diagram of the variant embodiment of FIGS. 1 and 2 with n pistons.
FIG. 5 is a schematic diagram of a second embodiment of the present invention.

1 and 2, the pump according to the present invention includes a piston 1a and a piston 1b.
The piston 1a and the piston 1b are operated by two parallel cams 2a and 2b supported by the camshaft 3, respectively.

Each of the cam 2a and the cam 2b includes three lobes.
The lobes are arranged at 120 ° to each other (this is illustrated in FIG. 3).

As is known per se, the piston 1a and the piston 1b move the hydraulic fluid into the bellows 4a and 4b that expand and contract in the chambers 5a and 5b, respectively.
The inside of the bellows 4a and 4b receives high-pressure hydraulic fluid when the piston 1a and piston 1b are raised, and the high pressure is transmitted to the fuel existing in the chamber 5a and chamber 5b.

  According to the present invention, the fuel enters the chamber 5a and the chamber 5b via a single supply path 6 including the branch 6a and the branch 6b.

  The supply path 6 has a flow rate control electromagnetic valve 8 that measures and controls the amount of fuel that can be introduced into the chamber 5a and the chamber 5b, and is connected to a tank via an orifice 7 that is a supply port. .

The fuel supplied through the supply path 6 through the backflow prevention valve 7a and the backflow prevention valve 7b can enter the chamber 5a and the chamber 5b.
Further, the fuel discharged at a high pressure by the bellows 4a and the bellows 4b by the backflow prevention valve 9a and the backflow prevention valve 9b flows in the discharge passage 10 in one direction toward the orifice 11 which is a discharge port.

  The cam 2a and the cam 2b are preferably offset by 60 °.

This arrangement provides the following advantages.
Because of the supply and discharge paths, there are fewer components than using two standard monopiston pumps.
In particular, there is only one flow control solenoid valve 8 for controlling the amount of fuel sent to the engine.
The stress that the piston exerts on the camshaft 3 is less than with a single piston at the same cylinder volume.
By shifting the angles of the two cams 2, there is an effect of improving the gradual progress of the flow under pressure toward the injection rail, and the change in torque to the camshaft can be reduced.

In the embodiment shown in FIG. 1, the discharge passage 10 is common to the piston 1a and the piston 1b. However, the present invention is not limited to this specific embodiment, and as shown in FIG. The discharge path 10a and the discharge path 10b can be arranged exclusively for the piston.
In FIG. 2, the same elements as those in FIG.

  FIG. 4 shows a modified embodiment, but the same components are denoted by the same reference numerals.

In this modification, two or more pistons 1a, 1b,. . . , Pistons 1n are present, each of which includes a cam 2a, a cam 2b,. . . And is driven by a cam 2n.
These cams 2a, cams 2b,. . . The cams 2n are parallel to each other and supported by the same camshaft 3.

  As in the case of FIG. 1, there is a discharge path 10 common to all n pistons, but as in the case of FIG. 2, one discharge path (10a, 10b,..., 10n) is provided for each piston. It is also possible to arrange.

  The difference from the pump of FIG. 1 is that the piston 1a and the piston 1b are moved by only a single cam (the camshaft 3 is shown symbolically), but these pistons 1a and 1b are arranged in a V shape. , The axis line is 60 °.

  The same advantages as the embodiment of FIG. 2 are obtained, but the whole is a little more compact.

  FIG. 5 similarly shows the branches 6a, 6b,. . . , Supplementary piston 1a, piston 1b,. . . , The piston 1m is illustrated symbolically, which is a branch 10a, a branch 10b,. . . Are connected by a branch 10m.

  FIG. 5 shows that a plurality of m pistons can be arranged radially around the cam 2.

  In all the illustrated embodiments, the cam 2 comprises three lobes arranged at 120 ° to each other, but it should be noted that the present invention is not limited to this particular embodiment. There is a need and the cam 2 may comprise one or more lobes.

It is the schematic of the 1st Example of this invention. It is a modification of FIG. FIG. 2 is a perspective view illustrating a pump according to FIG. 1. FIG. 3 is a schematic view of the modified embodiment of FIGS. 1 and 2 with n pistons. It is the schematic of the 2nd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piston 1a-1n Piston 2 Cam 2a-2n Cam 3 Camshaft 4 Bellows 4a-4n Bellows 5 Chamber 5a-5n Chamber 6 Supply path 6a, 6b Branch 7 Orifice 7a, 7b Backflow prevention valve 8 Flow control solenoid valve 9a, 9b Backflow prevention valve 10 Discharge path 10a, 10b Discharge path 11 Orifice

Claims (7)

The movable pump part is a transfer pump with a bellows (4) that is alternately filled with high-pressure hydraulic fluid or emptied by a piston (1) operated by a cam (2),
The amount of fuel entering the chamber (5) due to the expansion and contraction of the bellows (4) is determined upstream by a flow control solenoid valve (8) controlled by the engine control computer,
The piston (1) and bellows (4) form a pump unit,
The transfer pump includes two or more pump units,
Fuel is supplied to each pump unit via a single supply path (6) common to each pump unit in which a flow control solenoid valve (8) is arranged upstream,
Moreover, each pump unit is provided with the single discharge path (10) common or dedicated to each pump unit, The transfer pump characterized by the above-mentioned.   2. Pump according to claim 1, characterized in that the piston (1) is operated by a dedicated monolobe or multilobe cam (2).   Plural pistons (1a, 1b) for expanding and contracting bellows (4a, 4b, ..., 4n) disposed in chambers (5a, 5b, ..., 5n) connected to a common supply path (6) 3. The pump according to claim 2, comprising: 1 n).   The pump according to claim 3, characterized in that the chambers (5a, 5b, ..., 5n) are connected to a common drain (10).   The pistons (1a, 1b, ..., 1n) are respectively operated by monolobe or multilobe cams (2a, 2b, ..., 2n) arranged parallel to the camshaft (3). The pump according to any one of claims 1 to 4.   The pump according to claim 3, characterized in that each chamber (5a, 5b, ..., 5n) is connected to a dedicated discharge path. The pistons (1a, 1b, ..., 1n) are operated by a single cam (2);
The pump according to any one of claims 1 to 4, characterized in that the pistons are arranged radially around a cam (2).

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