JP2001099028A - Fuel supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately put flow amount characteristics of fuel pumps to a reference value by eliminating flow amount variation by means of a driving circuit arranged on the fuel pump. SOLUTION: A filter case 6 and a fuel pump 7 are attached inside a fuel tank 1 by using an attachment member 3 on whose upper surface side a pump driving device 3 is arranged. An adjusting resistance is arranged on the pump driving device 13, which corrects a driving signal to be output to the fuel pump 7 in respect to a command signal input from a control unit. A characteristic flow amount variation of the fuel pump 7 is adjusted by means of the adjusting resistance. It is thus possible to obtain a reference value in flow amount characteristics of the fuel pumps 7 against a command signal from the control unit. A discharge amount of the fuel pump 7 can accurately be controlled by the control unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device suitably used for supplying fuel in a tank to, for example, an automobile engine.

[0002]

2. Description of the Related Art Generally, a fuel supply device attached to an automobile engine or the like is provided with a fuel pump for discharging fuel in a tank toward an injection valve, and the fuel pump corresponding to a fuel injection amount by the injection valve. A control unit that outputs a command signal for driving with the discharge flow rate, a pump drive control circuit that outputs a drive signal corresponding to the command signal output from the control unit to the fuel pump, and drives and controls the fuel pump. (For example, JP-A-6-147047, JP-A-7-29397).

[0003] This type of prior art fuel supply system is:
An injection valve of the engine is connected to a discharge side of the fuel pump via a supply pipe or the like, and a fuel pressure sensor located near the injection valve and detecting a fuel pressure in the supply pipe is provided in the supply pipe. . Then, during operation of the engine, when an injection signal corresponding to the operation state or the like is output from the control unit to the injection valve, the fuel in the supply pipe is injected from the injection valve toward the combustion chamber of the engine. At this time, the pressure in the supply pipe changes according to the fuel injection amount.

For this reason, the control unit detects a change in fuel pressure using a fuel pressure sensor and outputs a command signal corresponding to the change to the pump drive control circuit. Drive the pump,
The fuel is discharged from the fuel pump to the injection valve at a discharge flow rate corresponding to the fuel injection amount. Thus, the control unit performs feedback control of the fuel pressure in the supply pipe using a fuel pump, a fuel pressure sensor, and the like, and holds the injected fuel at a constant pressure.

[0005]

In the above-mentioned prior art, the fuel flow characteristics of the fuel pump differ from each other with respect to a predetermined design standard (reference characteristic) or the like. In many cases, an error is included, and even if a plurality of fuel pumps are driven by a constant drive signal, the discharge flow rate of these may vary, for example, from about 65 to 105 (liter / hour). .

Therefore, when such a fuel pump is used, a fuel pressure sensor is provided in the supply pipe, and the discharge flow rate of the fuel pump is changed in accordance with the fuel pressure detected by the fuel pressure sensor, so that the injected fuel is kept constant. The pressure is feedback controlled to reduce the variation in the flow rate of the fuel pump.

However, in the prior art, since it is necessary to use a fuel pressure sensor, the number of parts increases, which leads to an increase in cost. In addition, depending on the fuel pump, the flow rate variation may be relatively large, and during the fuel pressure feedback control, the feedback control may be adversely affected by the fuel pump flow rate variation.
As a result, during the operation of the engine, the responsiveness and accuracy of the fuel pressure control may be reduced, and the fuel pressure may easily fluctuate.
There is a problem that reliability is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to correct the variation in the flow rate of the fuel pump so that the flow rate characteristic of the fuel can be made closer to the reference flow rate characteristic. An object of the present invention is to provide a fuel supply device capable of supplying fuel at a stable pressure toward an injection valve by a pump, and simplifying the structure of the entire device, improving reliability, and the like.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a fuel pump for discharging fuel in a tank toward an injection valve, and the fuel pump is adapted for the fuel injection amount by the injection valve. Command signal output means for outputting a command signal for driving with the discharged discharge flow rate, and a pump drive for outputting a drive signal corresponding to the command signal output from the command signal output means to the fuel pump to drive and control the fuel pump. The present invention is applied to a fuel supply device comprising control means.

A feature of the structure adopted by the first aspect of the present invention is that the pump drive control means changes the flow rate characteristic of the fuel discharged from the fuel pump in accordance with the drive signal to a predetermined reference flow rate characteristic. A drive signal correcting means for correcting the drive signal with respect to a command signal output from the command signal output means for providing a close approach is provided.

With this configuration, the drive signal correction means can correct the drive signal output to the fuel pump in response to the command signal output from the command signal output means. As a result, the drive signal correction unit can absorb, for example, individual flow rate variations that differ for each fuel pump by correcting the output of the drive signal, and can make the flow characteristics of the plurality of fuel pumps close to substantially the same flow characteristics.

According to a second aspect of the present invention, the drive signal correction means is constituted by an offset adjusting resistor for adjusting the drive signal by offsetting the drive signal in a decreasing direction with respect to the command signal output from the command signal output means. are doing.

Accordingly, even when the flow rate characteristic of the fuel pump includes an error in the direction in which the flow rate increases with respect to the reference flow rate characteristic due to, for example, a design margin, the drive signal correction means can control the command signal with respect to the command signal. Thus, the drive signal can be offset and adjusted in the decreasing direction, and the error in the flow characteristic of each fuel pump can be reduced.

Further, according to the third aspect of the present invention, the drive signal correction means is constituted by an inclination adjusting resistor for adjusting the inclination of the drive signal with respect to the command signal output from the command signal output means.

Thus, even if the rate of increase / decrease when the discharge flow rate from the fuel pump increases / decreases in accordance with the drive signal includes an error with respect to the rate of increase / decrease of the reference characteristic, the drive signal correction means can output the command signal. The slope of the drive signal output to the fuel pump with respect to the command signal output from the means can be adjusted,
By adjusting this inclination, it is possible to reduce the error included in the rate of change in the discharge flow rate.

On the other hand, a feature of the structure adopted by the invention of claim 4 is that, on the discharge side of the fuel pump, the flow rate characteristic of the fuel discharged from the fuel pump is determined in advance according to the drive signal from the pump drive control means. In order to approximate the reference flow rate characteristic, a flow rate correction means for correcting a discharge flow rate of the fuel by releasing a part of the fuel discharged by the fuel pump is provided.

Thus, the flow rate correcting means can correct a discharge flow rate of the fuel by releasing a part of the fuel discharged from the fuel pump to the fuel tank or the like. As a result, the flow characteristic of the fuel pump can be corrected in a decreasing direction with respect to the drive signal in accordance with the amount of fuel released by the flow correction means, and this flow characteristic can be made closer to the reference flow characteristic.

According to the invention of claim 5, the fuel pump is provided with a mounting member for mounting the fuel pump in the tank, and the pump drive control means is provided on the mounting member.

Thus, for example, the fuel pump and the pump drive control means can be assembled in advance as an integrated unit using the mounting member, and the flow characteristics of the fuel pump can be corrected in the state of this unit. Thus, for example, in an assembly line of a fuel supply device, the flow characteristics of each fuel pump are aligned with the reference flow characteristics with respect to the command signal output means in a state where all the fuel pumps are unitized with the pump drive control means. Can be.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fuel supply device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking an example in which the fuel supply device is applied to an automobile engine or the like.

FIGS. 1 to 6 show a first embodiment of the present invention. In the drawings, reference numeral 1 denotes a fuel tank provided in a vehicle such as an automobile. ,
As shown in FIG. 2, a mounting hole 1A for a mounting member 3 described later is provided.

Reference numeral 2 denotes a pump unit provided in the fuel tank 1. The pump unit 2 includes a mounting member 3, a filter case 6, a fuel pump 7, and a pump driving device 13, which will be described later.

Reference numeral 3 denotes a resin mounting member provided on the upper surface of the fuel tank 1. The mounting member 3 includes, as shown in FIGS. 2 and 3, a lid 3A for closing the mounting hole 1A, and a lid 3A. And a bracket 3B having a filter case 6 attached to a tip end thereof, which is suspended from the portion 3A into the fuel tank 1.

A metal supply pipe 4 for supplying fuel to the outside of the fuel tank 1 is buried in the lid 3A, and the upper side (outflow side) of the supply pipe 4 is bent in a substantially L-shape. The lower side (inflow side) protrudes into the tank 1 while protruding above the lid 3A. A power supply terminal 5 for the fuel pump 7 is embedded in the lid 3A.

Reference numeral 6 denotes a filter case formed of a resin material or the like into a substantially cylindrical shape. The filter case 6 is mounted in the fuel tank 1 using a mounting member 3 as shown in FIG. In the filter case 6, a fuel pump 7 is provided together with a filter element (not shown) of the fuel filter. A discharge pipe 6A for discharging fuel from the fuel pump 7 to the outside is projected from the filter case 6, and the discharge pipe 6A is connected to the supply pipe 4 on the mounting member 3 side.

Reference numeral 7 denotes a fuel pump fixed in a filter case 6. The fuel pump 7 has a suction port 7A connected to a suction filter 7B in the fuel tank 1, and a discharge port (not shown) connected to a fuel filter. And is connected to the discharge pipe 6A of the filter case 6 via the. The wiring 7C of the fuel pump 7 is connected to the pump driving device 13 via the power supply terminal 5.

When the driving signal D is output from the pump driving device 13 as described later, the built-in electric motor (not shown) of the fuel pump 7 is driven to rotate, whereby the fuel in the fuel tank 1 is discharged. This fuel is discharged from the fuel filter into the discharge pipe 6A of the filter case 6 while being sucked from the suction port 7A.

Numerals 8, 8,... Are a plurality of injection valves provided in the engine body 9, and each of the injection valves 8 is connected to a supply pipe 4 using a connection pipe 10 and a supply pipe 11 as shown in FIG. The fuel is discharged from the fuel pump 7 and is injected into a combustion chamber (not shown) of the engine body 9.

Here, the discharge flow rate Q of the fuel discharged from the fuel pump 7 toward each of the injection valves 8 is proportional to the voltage value of the drive signal D, for example, as shown by a characteristic line Lp in FIG. Changes to However, since the fuel pump 7 is composed of a number of parts including the electric motor, the flow characteristics thereof are individually determined by accumulating, for example, characteristic variations of the electric motor, dimensional errors of each part, assembly errors, and the like. Each pump has a unique flow rate variation that differs.

Therefore, when the plurality of fuel pumps 7 are compared, they have different flow characteristics, for example, as indicated by characteristic lines Lp, Lp ', Lp ". Therefore, in a fuel supply device assembly line or the like, a large number of previously assembled fuel pumps are provided. Fuel pump 7
Among them, for example, only those whose characteristic line of the flow rate falls within a design allowable range M shown in FIG. 5 are selected and used for assembling.

Reference numeral 12 denotes a control unit as command signal output means constituted by, for example, a microcomputer or the like. As shown in FIG. 1, the control unit 12 responds to each injection valve 8 according to the operating state of the engine and the like. By outputting an injection signal, fuel is injected from these injection valves 8 to the engine body 9.

The control unit 12 outputs a command signal S for driving the fuel pump 7 to the pump driving device 13 using a pulsed voltage signal by means of, for example, PWM or the like. Pump 7
Is controlled so that the injection fuel is maintained at a constant pressure.

Here, the control unit 12 sends a command signal S corresponding to the fuel injection amount or the like to the pump driving device 13.
The fuel is discharged from the fuel pump 7 with a discharge flow rate Q that compensates for the fuel injection amount. However, when the fuel pump 7 has a flow rate variation that differs for each pump, the discharge flow rate Q cannot be accurately controlled. Therefore, in the present embodiment, the drive signal D output to the fuel pump 7 by the pump drive device 13 is corrected according to the flow rate variation of each pump as described later.

Reference numeral 13 denotes a pump drive unit as a pump drive control unit for controlling the drive of the fuel pump 7. The pump drive unit 13 is provided on the cover 3A of the mounting member 3, as shown in FIGS. Circuit case 13A. The circuit case 13A has a tilt adjusting resistor 2 to be described later.
7. A plurality of circuit elements including an offset adjustment resistor 35 (see FIG. 4) and the like are mounted, and these are connected to the control unit 12 via the connector 13B.

When the command signal S shown in FIG. 4 is output from the control unit 12, the pump driving device 13 drives the drive signal D corresponding to the voltage value of the command signal S and the like.
Is output to the fuel pump 7, and the drive signal D at this time is corrected using the inclination adjustment resistance 27 and the offset adjustment resistance 35. As a result, the pump driving device 13 corrects the apparent flow characteristic of the fuel pump 7 via the pump driving device 13 in response to the command signal S from the control unit 12, and the pump driving device 13 almost uniformly satisfies the design reference characteristics. The fuel is discharged from the fuel pump 7 with the discharge flow rate Q.

Here, the apparent flow rate correction will be described in principle. First, the fuel pump 7 has a flow rate variation within a design allowable range M, for example, as shown by characteristic lines Lp, Lp ', Lp "shown in Fig. 5. Therefore, the pump driving device 13 has these characteristics. Lines Lp, Lp ', L
The output of the drive signal D is corrected so that p ″ becomes substantially equal to the reference characteristic line Ls, which apparently forms the lower limit of the allowable range M with respect to the command signal S. Then, for example, the characteristic line Lp
In principle, the inclination of the characteristic line Lp is adjusted in the direction of arrow A so as to be substantially parallel to the reference characteristic line Ls, and the characteristic line Lp is translated in the direction of arrow B ( The characteristic line Lo of the drive signal D shown in FIG. 6, which will be described later, is changed like a characteristic line Lc so that the characteristic line Lc overlaps with the reference characteristic line Ls.

Next, with reference to FIG.
The circuit configuration of No. 3 will be described. In the figure, reference numeral 21 denotes an amplification factor adjusting circuit for adjusting an amplification factor for a command signal S input from an input terminal 22 via a resistor 23 and a capacitor 24. The circuit 21 includes an operational amplifier 25 and a resistor 2
6 and a tilt adjustment resistor 27 described later, and amplifies the drive signal D with respect to the command signal S at an amplification factor according to the resistance value of the tilt adjustment resistor 27.

Numeral 27 denotes a slope adjusting resistor as a drive signal correcting means constituted by, for example, a variable resistor. The resistance value of the slope adjusting resistor 27 is adjusted at the time of adjusting the flow rate of the pump unit 2 and is required from the initial resistance value. It is changed according to. The slope adjusting resistor 27 adjusts a resistance value (amplification rate of the drive signal D) to thereby adjust the resistance value (see FIG. 6 described later).
The inclination of the characteristic line Lo before the adjustment shown by the two-dot chain line is changed like the characteristic line Lc after the adjustment.

Reference numeral 28 denotes an offset adjustment circuit provided on the output side of the amplification factor adjustment circuit 21.
8 is an operational amplifier 29 and resistors 30, 31, 32, 3
The drive signal D is reduced (offset) by a voltage value corresponding to the resistance value of the offset adjustment resistor 35 with respect to the command signal S.

Numeral 35 denotes an offset adjusting resistor as a drive signal correcting means composed of, for example, a variable resistor. Has been adjusted. The offset adjustment resistor 35 adjusts the resistance value to reduce the drive signal D with respect to the command signal S, and changes the characteristic line Lo before adjustment shown in FIG. 6 to the characteristic line Lc after adjustment. This is for changing the offset amount when performing parallel movement (offset) in the horizontal axis direction.

The output characteristic of the drive signal D is adjusted to the state of the characteristic line Lc by using the inclination adjusting resistor 27 and the offset adjusting resistor 35 during the flow adjusting operation of the pump unit 2 described later. As a result, when a command signal S having a voltage value VS1 is output from the control unit 12 as described later, the fuel pump 7 outputs a discharge flow rate Q1 which is predetermined as a design standard corresponding to the voltage value VS1.
And discharges the fuel at a predetermined discharge flow rate Q2 in response to a command signal S having a voltage value VS2.

An oscillation circuit 36 includes an operational amplifier 37 and the like. The oscillation circuit 36 generates, for example, a pulse signal having a substantially triangular waveform in a comparison circuit 38 described later at a constant period.

Reference numeral 38 denotes a comparison circuit including a comparator 39 and the like.
The comparison circuit 38 compares the pulse signal generated from the oscillation circuit 36 with the output signal from the offset adjustment circuit 28, and converts the pulse signal having a variable duty ratio in accordance with the voltage value of the output signal. The signal is output to a drive signal output circuit 40 described later.

A drive signal output circuit 40 includes transistors 41 and 42. The drive signal output circuit 40 has an output terminal 4 according to a pulse signal output from the comparison circuit 38.
3 outputs a drive signal D. Thereby, the drive signal D
Is output as a pulse signal having a constant period. Also,
The voltage values VD1, VD1 ', VD2 of the drive signal D, which will be described later, are defined as time-averaged values of the pulse signal voltage values over one cycle, similarly to the command signal S voltage values VS1, VS2. .

The fuel supply device according to the present embodiment has the above-described configuration, and its operation will now be described.

First, the control unit 12 is configured as shown in FIG.
The fuel is injected from the middle injection valve 8 in an amount corresponding to the operating state of the engine, and a command signal S corresponding to the fuel injection amount is output to the pump driving device 13. As a result, when the drive signal D is output from the pump drive device 13 to the fuel pump 7, the fuel pump 7
Then, the fuel in the fuel tank 1 is discharged, and this fuel is supplied to the injection valve 8 via the supply pipe 4, the connection pipe 10, the supply pipe 11, and the like. Thus, the fuel injected from the injection valve 8 is maintained at a constant pressure by the open loop control of the control unit 12.

Next, for example, an assembling operation performed on an assembly line of a fuel supply device will be described.
First, after assembling the pump unit 2 as an integral unit, a flow rate adjusting operation of the fuel pump 7 is performed on the pump unit 2.

Here, before performing this flow rate adjusting operation,
The inclination adjustment resistor 27 and the offset adjustment resistor 35 are set to the initial resistance values, and the output characteristics of the drive signal D are, for example, in the state of the characteristic line Lo before adjustment indicated by a two-dot chain line in FIG. .

In this state, for example, when the control unit 12 outputs the command signal S having the voltage value VS1,
The pump driving device 13 determines the voltage value VD according to the characteristic line Lo.
A drive signal D having 1 'is output. At this time, if the fuel pump 7 has a flow characteristic according to the reference characteristic line Ls, the fuel pump 7 discharges the fuel at a predetermined discharge flow rate Q1 according to the reference characteristic line Ls.

However, the actual flow characteristic of the fuel pump 7 includes a flow rate variation as shown by a characteristic line Lp.
The fuel pump 7 discharges fuel at a discharge flow rate Q1 'including an error according to the characteristic line Lp. Also, when the control unit 12 outputs the command signal S having the voltage value VS2, the fuel pump 7 includes an error due to the characteristic line Lp instead of the discharge flow rate Q2 predetermined by the reference characteristic line Ls. The fuel is discharged at the discharge flow rate Q2 '.

Therefore, in the flow rate adjusting operation of the fuel pump 7, the discharge flow rate Q1 corresponds to the voltage value VS1 of the command signal S,
The characteristic line Lo of the drive signal D is adjusted so that the discharge flow rate Q2 corresponds to the voltage value VS2 of the command signal S.

More specifically, first, the fuel pump 7 is driven by the drive signal D, and the voltage value VD1 of the drive signal D when the fuel is discharged at the discharge flow rate Q1 and when the fuel is discharged at the discharge flow rate Q2. And the voltage value VD2 of the drive signal D is measured.

Next, for example, while measuring and comparing the command signal S and the drive signal D, the resistance of the slope adjusting resistor 27 is changed to adjust the slope of the characteristic line Lo, and the resistance of the offset adjusting resistor 35 is adjusted. The characteristic line Lo is offset in the horizontal axis direction by changing the value. Thereby, the output characteristic of the drive signal D is changed to the state of the characteristic line Lc, and the command signal S
When S1, the drive signal D has the voltage value VD1, and when the command signal S has the voltage value VS2, the drive signal D has the voltage value VD2.
So that

As a result, when the command signal S having the voltage value VS1 is output from the control unit 12, the fuel pump 7 is supplied with the drive signal D having the voltage value VD1 so that the fuel pump 7 has the discharge flow rate Q1 according to the characteristic line Lp. Discharge the fuel. Further, when the command signal S having the voltage value VS2 is output, the fuel pump 7 is supplied with the drive signal D having the voltage value VD2 to discharge the fuel at the discharge flow rate Q2.

Thus, the fuel pump 7 is adjusted in response to the command signal S from the control unit 12 so that the apparent flow characteristic via the pump driving device 13 satisfies the characteristic line Ls. In an assembly line or the like, all the pump units 2 are adjusted to have a design reference characteristic by a flow rate adjusting operation.

Thus, in the present embodiment, the apparent flow characteristic of the fuel pump 7 with the pump driving device 13 interposed therebetween is obtained by using the inclination adjusting resistance 27 and the offset adjusting resistance 35 provided in the pump driving device 13. Since the drive signal D is corrected so as to satisfy the line Ls, even if the fuel pump 7 has a flow rate variation peculiar to each pump such as the characteristic lines Lp, Lp ', Lp ", these flow rate variations are reduced. Drive signal D using adjustment resistors 27 and 35
And the flow characteristic of the fuel pump 7 can be made to substantially match the reference flow characteristic with respect to the command signal S.

For example, in the assembly line of the pump unit 2 or the like, the fuel pump 2 and the pump driving device 13 are assembled as an integrated unit in advance, and then the flow adjustment operation is performed. The characteristics can be made uniform and it is possible to prevent the flow rate variation between the pump units 2 from occurring.

Therefore, according to the present embodiment, when the control unit 12 outputs the command signal S corresponding to the fuel injection amount of the injector 8, the fuel pump 7 uses the discharge flow rate Q corresponding to the command signal S. Fuel can be accurately discharged toward the injection valve 8. As a result, there is no need to perform fuel pressure feedback control using a fuel pressure sensor or the like as in the prior art, and the pressure of the injected fuel can be stably controlled by performing open loop control by the control unit 12. As a result, the structure of the entire device can be simplified, cost can be reduced, and reliability can be improved.

In this case, since the drive signal D is corrected by using the slope adjustment resistor 27 and the offset adjustment resistor 35, the characteristic line L of the drive signal D is corrected by the slope adjustment resistor 27.
The inclination (amplification factor) of o can be adjusted, and the characteristic line Lo can be offset in the horizontal axis direction by reducing the drive signal D using the offset adjustment resistor 35, and the offset amount can be adjusted.

As a result, even when the characteristic line Lp of the fuel pump 7 includes an error such that the characteristic line Lp deviates from the characteristic line Ls in the direction in which the flow rate increases due to, for example, margins in design, the offset adjustment resistor 35 can be used. The error can be reliably reduced by offsetting the characteristic line Lo of the drive signal D in the decreasing direction.

Further, even if the rate of change (gradient of the characteristic line Lp) when the discharge flow rate Q of the fuel pump 7 increases or decreases in accordance with the drive signal D includes an error with respect to the reference characteristic line Ls, the gradient does not change. This error can be reduced by adjusting the slope of the characteristic line Lo using the adjustment resistor 27.

On the other hand, since the circuit case 13A of the pump driving device 13 is provided on the lid 3A of the mounting member 3, the fuel pump 7 and the pump driving device 13 are used as the pump unit 2 when assembling the fuel supply device. By integrating the flow rate of the fuel pump 7 in this state,
The fuel flow characteristics can be made uniform for all the pump units 2. As a result, parts management of the pump unit 2 can be easily performed.

Further, since the pump driving device 13 can be arranged near the fuel pump 7, it is not necessary to extend a long lead wire or the like between the fuel pump 7 and the pump driving device 13, for example. It is possible to improve the noise resistance by shortening the above, and to omit, for example, a shield member for a lead wire and a noise reduction circuit.

Next, FIGS. 7 and 8 show a second embodiment according to the present invention.
In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. However, a feature of the present embodiment is that a flow rate correction valve is provided on the discharge side of the fuel pump.

Reference numeral 51 denotes a pump unit of the fuel supply device.
The pump unit 51 includes a mounting member 3, a fuel pump 7, and a pump driving device 13, substantially in the same manner as the pump unit 2 of the first embodiment. However, the filter case 52 of the pump unit 51 is provided with a flow rate correction valve 53 described later, which is located in the middle of the discharge pipe 52A.

Reference numeral 53 denotes a flow rate correction valve provided as a flow rate correction means provided in the filter case 52.
As shown in FIG. 8, a substantially bottomed tubular valve cylinder 53A protruding radially from an intermediate portion of the discharge pipe 52A,
3A and a valve element 53B screwed into the valve element 3A.

Here, the discharge pipe 52 is connected to the valve cylinder 53A.
A is provided with an inflow port 53C and an outflow port 53D that open to the inside and outside of A. Further, the valve body 53B advances and retreats in the valve cylinder 53A by being rotated from the outside using a tool (not shown) such as a driver, and has an opening 53C and an outlet 53C with an opening corresponding to the amount of rotation. This adjusts the flow path area between the flow path 53D.

The flow correction valve 53 is connected to the fuel pump 7
Out of the fuel discharged into the discharge pipe 52A of the filter case 52 from the outlet 53D side into the fuel tank 1 according to the opening degree of the valve body 53B. Discharge flow rate Q to pump drive 1
3 is to be corrected.

In this case, for example, at the time of adjusting the flow rate of the fuel pump 7, first, the drive signal D is supplied to the fuel pump 7 to discharge the fuel, and the discharge flow rate of the fuel actually discharged from the discharge pipe 52 A of the filter case 52. Measure Q. The opening of the flow rate correction valve 53 is adjusted so that the relationship between the discharge flow rate Q and the drive signal D satisfies, for example, the reference characteristic line Ls (see FIG. 5) in the first embodiment. The fuel is returned into the fuel tank 1 from the flow correction valve 53 side.

Thus, in the present embodiment configured as described above, substantially the same operation and effect as in the first embodiment can be obtained. And especially in this embodiment,
By using the flow rate correction valve 53, the discharge flow rate Q of the fuel pump 7 can be offset with respect to the drive signal D in the direction of decreasing the flow rate with a simple structure, and is shown in FIG. 5 in the first embodiment, for example. The characteristic line Lp can be translated in the direction of the arrow B so as to be corrected so that the characteristic line Lp of the flow rate approaches the reference characteristic line Ls.

Therefore, the amount of deviation (offset) in the vertical axis direction between the characteristic lines Lp and Ls, which greatly affects the variation in the flow rate of the fuel pump 7, can be easily adjusted by the flow rate correction valve 53, and the pump driving device 13 can be simplified. In addition to the above, the work of adjusting the flow rate of the fuel pump 7 can be performed efficiently.

In the second embodiment, the flow rate compensating valve 53 is provided on the discharge pipe 52A of the filter case 52. However, the present invention is not limited to this. For example, as shown in a modified example shown in FIG. Alternatively, a flow correction valve 62 may be provided on a supply pipe 61 provided on the mounting member 3 and connected to the discharge pipe 6A of the filter case 6.

In the second embodiment, a part of the fuel discharged from the fuel pump 7 is released into the fuel tank 1 in accordance with the opening of the flow correction valve 53. However, the present invention is not limited to this. Instead, for example, a fuel release hole or the like serving as a flow rate correction means is provided in the discharge pipe of the filter case, and the discharge flow rate is corrected by adjusting the diameter of the fuel release hole using a jig for drilling. Is also good.

Further, in the first embodiment, the inclination adjusting resistor 27 and the offset adjusting resistor 35 are constituted by a variable resistor or the like, but the present invention is not limited to this. 13 may be constituted by a resistive element or the like which is exchangeably attached to.

Further, in the first embodiment, the inclination (amplification factor) of the drive signal D is adjusted using the inclination adjustment resistor 27, and the drive signal D is offset with respect to the command signal S using the offset adjustment resistor 35. However, the present invention is not limited to this, and one of the inclination adjustment resistor 27 and the offset adjustment resistor 35 may be omitted and the drive signal D may be corrected using only the other.

Further, in the first embodiment, the discharge flow rate Q of the fuel pump 7 is changed in accordance with the voltage value of the drive signal D. However, the present invention is not limited to this. It may be configured to change according to the current value of the drive signal D or the like.

Further, in the first embodiment, for example, P
A command signal S generated as a pulse signal by means such as WM is transmitted from the control unit 12 to the pump driving device 13.
However, the present invention is not limited to this. For example, the command signal S may be configured by a DC voltage signal or the like.

In each of the above embodiments, the injection fuel is opened by changing the discharge flow rate of the fuel pump 7 in accordance with the fuel injection amount without detecting the pressure of the injection fuel using a fuel pressure sensor or the like. Although the configuration is such that the loop control is performed, the present invention is not limited to this. For example, a fuel pressure sensor or the like may be provided in the supply pipe 11 and the control unit 12 may feedback control the pressure of the injected fuel as in the related art.

[0079]

As described in detail above, according to the first aspect of the present invention, the pump drive control means is provided with the drive signal correction means for correcting the drive signal with respect to the command signal. Even if the flow characteristics of the pump include a flow variation peculiar to each pump, this flow variation can be absorbed by the output correction of the drive signal by the drive signal correction unit, and the fuel pump responds to the command signal from the command signal output unit. The fuel can be accurately discharged with a discharge flow rate close to the reference flow characteristic. Therefore, the pressure of the injected fuel can be stably controlled using the fuel pump by the control unit without using a fuel pressure sensor or the like as in the prior art, and the overall structure of the apparatus can be simplified to reduce costs. , Reliability can be improved. Also, for example, in an assembly line of a fuel supply device,
It is possible to make uniform the apparent flow characteristics of all the fuel pumps via the pump drive control means, and to easily manage these parts in a state where the fuel pump and the pump drive control means are unitized. Can be.

According to the second aspect of the present invention, the drive signal correction means is constituted by the offset adjusting resistor for adjusting the drive signal by offsetting the drive signal in the decreasing direction with respect to the command signal from the command signal output means. For example, even if the flow characteristic of the fuel pump includes an error that deviates from the reference flow characteristic in the increasing direction of the flow due to margins in design, the drive signal is decreased in the decreasing direction by using the offset adjustment resistor. The offset can be performed, thereby reducing the error of the flow characteristic.

Further, according to the third aspect of the present invention, the drive signal correction means is constituted by the inclination adjusting resistor for adjusting the inclination of the drive signal with respect to the command signal from the command signal output means, so that the discharge of the fuel pump is achieved. Even if the rate of change when the flow rate increases or decreases in response to the drive signal includes an error with respect to the rate of increase or decrease of the reference characteristic, the slope of the drive signal can be adjusted using the slope adjustment resistor, thereby providing an error in the flow rate characteristic. Can be reduced.

On the other hand, according to the fourth aspect of the present invention, the discharge side of the fuel pump is provided with a flow rate correcting means for releasing a part of the fuel discharged by the fuel pump and correcting the discharge flow rate of the fuel. By using the flow rate correcting means, the discharge flow rate of the fuel pump can be offset in the direction of decreasing the flow rate with respect to the drive signal with a simple structure, and the flow rate characteristic is corrected for each fuel pump so as to approach the reference flow rate characteristic. be able to. Therefore, the amount of deviation between the flow rate characteristic of the pump and the reference flow rate characteristic, which greatly affects the flow rate variation of the fuel pump, can be easily adjusted by the flow rate correction means, and the pump drive control means can be simplified. In addition, the operation of adjusting the flow rate of the fuel pump can be performed efficiently.

According to the fifth aspect of the present invention, the pump driving control means is provided on the mounting member for mounting the fuel pump in the tank.
The fuel pump and the pump drive control means can be assembled in advance as an integrated unit. In this state, by performing a fuel pump flow adjustment operation or the like, the fuel flow characteristics can be made uniform for all units. it can. As a result, parts management of the unit including the fuel pump can be easily performed. Moreover, since the pump drive control means can be arranged near the fuel pump, the lead wires and the like connecting them can be shortened, the noise resistance can be improved, and, for example, a shield member and a noise reduction circuit for the lead wire are omitted. be able to.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a fuel supply system of an engine to which a fuel supply device according to a first embodiment of the present invention is applied.

FIG. 2 is an enlarged front view showing a pump unit in FIG. 1;

FIG. 3 is a plan view of the pump unit shown in FIG. 2;

FIG. 4 is a circuit diagram showing a pump driving device.

FIG. 5 is a characteristic diagram showing a flow characteristic including an individual error for each fuel pump and a reference flow characteristic.

FIG. 6 is a characteristic diagram illustrating a relationship among a command signal, a drive signal, and a discharge flow rate.

FIG. 7 is a front view showing a pump unit of a fuel supply device according to a second embodiment of the present invention.

FIG. 8 is an enlarged sectional view showing a flow correction valve and the like in FIG. 7;

FIG. 9 is an enlarged cross-sectional view of a flow rate correction valve and the like showing a modification of the second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fuel tank (tank) 2, 51 pump unit 3 mounting member 6 filter case 7 fuel pump 8 injection valve 12 control unit (command signal output unit) 13 pump drive unit (pump drive control unit) 21 amplification factor adjustment circuit 27 tilt adjustment Resistance (drive signal correction means) 28 Offset adjustment circuit 35 Offset adjustment resistance (drive signal correction means) 36 Oscillation circuit 38 Comparison circuit 40 Drive signal output circuit 53, 62 Flow rate correction valve (flow rate correction means)

Claims (5)

[Claims] 1. A fuel pump for discharging fuel in a tank toward an injection valve, and command signal output means for outputting a command signal for driving the fuel pump at a discharge flow rate corresponding to a fuel injection amount by the injection valve. And a pump drive control means for outputting a drive signal corresponding to the command signal output from the command signal output means to the fuel pump, and controlling the drive of the fuel pump. A drive that corrects the drive signal with respect to a command signal output from the command signal output means in order to bring a flow rate characteristic of the fuel discharged from the fuel pump close to a predetermined reference flow rate characteristic in accordance with the drive signal. A fuel supply device comprising signal correction means. 2. The apparatus according to claim 1, wherein said drive signal correcting means comprises an offset adjusting resistor for adjusting said drive signal by offsetting in a decreasing direction with respect to a command signal output from said command signal output means. The fuel supply device as described in the above. 3. The drive signal correction means according to claim 1, wherein said drive signal correction means comprises a tilt adjustment resistor for adjusting a tilt of said drive signal with respect to a command signal output from said command signal output means. Fuel supply device. 4. A fuel pump for discharging fuel in a tank toward an injection valve, and command signal output means for outputting a command signal for driving the fuel pump with a discharge flow rate corresponding to a fuel injection amount by the injection valve. A drive signal corresponding to the command signal output from the command signal output means, the drive signal being output to the fuel pump, and a pump drive control means for controlling the drive of the fuel pump. In order to make the flow characteristic of the fuel discharged from the fuel pump close to a predetermined reference flow characteristic in accordance with the drive signal from the pump drive control means, a part of the fuel discharged by the fuel pump is released to discharge the fuel. A fuel supply device comprising a flow rate correcting means for correcting a flow rate. 5. The fuel according to claim 1, wherein the fuel pump is provided with a mounting member for mounting the fuel pump in the tank, and the pump drive control means is provided on the mounting member. Feeding device.