JP2021161919A - Fuel supply device for internal combustion engine - Google Patents

Abstract

To achieve the sufficient size reduction of an oil level sensor compared with an oil level sensor structure having a conventional float and a long oscillation arm, to contribute to the size reduction of a fuel supply device, and to make the assembling workability of the fuel supply device favorable, in the fuel supply device with the oil level sensor.SOLUTION: An oil level sensor is constituted of a piezoelectric element S which is fixed to a hangout part 12 hanging into a fuel tank T of a box body 10 of a fuel supply device FM, and immersed into fuel in the fuel tank T, and the piezoelectric element S outputs an electrical detection signal corresponding to fuel weight at an upper part rather than the piezoelectric element S to a control device C, and the control device C makes an oil level display device M display a fuel oil level L on the basis of the detection signal.SELECTED DRAWING: Figure 1

Description

The present invention includes a fuel supply device for an internal combustion engine, particularly a fuel pump that is arranged in a fuel tank and sucks and discharges fuel in the fuel tank, and is fixed to the bottom of the fuel tank to close an opening at the bottom. A housing whose part projects into the fuel tank to hold the fuel pump, and a fuel outlet pipe which is projected from the lower outer surface of the housing and can be connected to a fuel pipe connected to a fuel injection valve for an internal combustion engine, and a housing. The present invention relates to a fuel supply device including a communication passage formed in the wall of the fuel pump for communicating the fuel discharge portion of the fuel pump with the fuel outlet pipe, and an oil level sensor for detecting the fuel oil level in the fuel tank.

The fuel supply device is conventionally known, for example, as disclosed in Patent Document 1, in which an oil level sensor is coupled to a long swing arm with a float fixed to a tip and a base of the arm. It has a rotor and a rotation detection unit that rotatably supports the rotor and detects the rotational displacement, and the fuel tank is based on the swing angle of the swing arm detected by the rotation detection unit. The fuel liquid level can be displayed sequentially on the external liquid level display device.

JP-A-2015-190425

However, in the fuel supply device for an internal combustion engine of Patent Document 1, the rotation detection unit is attached to the overhanging portion of the housing into the fuel tank, and the rotation detection portion is floated via a rotor and a long swing arm. Therefore, the overall size of the oil level sensor (hence, the fuel supply device) including the float and the swing arm becomes large.

Therefore, when assembling this fuel supply device to the fuel tank, as is clear from FIG. 8 of Patent Document 1, first, the float and the swing arm are inserted into the fuel tank from below through the tank opening, and then the casing is used. It is necessary to insert the overhanging portion of the body into the fuel tank through the tank opening with a change in the posture of the overhanging portion. This series of assembling work has a problem that the assembling workability is poor because it is troublesome and complicated, and the fuel supply device is assembled only to the fuel tank having a large tank space in which the range of motion of the float and the swing arm can be secured. There was also a problem that I couldn't do.

The present invention has been proposed in view of the above, and an object of the present invention is to provide a fuel supply device for an internal combustion engine capable of solving the above problems of a conventional device.

In order to achieve the above object, the present invention includes a fuel pump arranged in the fuel tank to suck and discharge the fuel in the fuel tank, and fixed to the bottom of the fuel tank to close the opening of the bottom. A housing in which a portion projects into the fuel tank to hold the fuel pump, a fuel outlet pipe projecting from the lower outer surface of the housing and connectable to a fuel pipe connected to a fuel injection valve for an internal combustion engine, and the above. Fuel supply for internal combustion engines including a communication passage formed in the wall of the housing and communicating the fuel discharge portion of the fuel pump to the fuel outlet pipe, and an oil level sensor for detecting the fuel oil level in the fuel tank. In the device, the oil level sensor is composed of a piezoelectric element fixed to the housing and immersed in the fuel in the fuel tank, and the piezoelectric element corresponds to the fuel weight above the piezoelectric element. A specific detection signal is output to the control device, and the control device causes the oil level display device to display the fuel oil level based on the detection signal.

Further, in addition to the first feature, in the present invention, the piezoelectric element is fixed to an overhanging portion of the housing into the fuel tank, and in the control device, the fuel oil level is the fuel weight of the piezoelectric element. When the fuel level drops below the level of the receiving portion, the fuel oil level estimated based on the integrated value of the valve opening time of the fuel injection valve after the drop below the level is displayed on the oil level display device. Is the second feature.

According to the first feature, the oil level sensor is composed of a piezoelectric element fixed to the housing and immersed in the fuel in the fuel tank, and the piezoelectric element corresponds to the fuel weight above this. Since the electric detection signal is output to the control device and the control device displays the fuel oil level on the oil level display device based on the detection signal, the oil level display device can be used even if the piezoelectric element is used for the oil level sensor. The fuel oil level can be displayed sequentially. In addition, the piezoelectric element that serves as the oil level sensor does not have a moving part that moves significantly in the fuel tank and is simply fixed to the housing. Therefore, it has a conventional oil level sensor structure with a float and a long swing arm. In comparison, the oil level sensor has been sufficiently miniaturized, which in turn can contribute to the miniaturization of the fuel supply device with the oil level sensor. The sex is also good.

According to the second feature, the piezoelectric element is fixed to the overhanging portion of the housing into the fuel tank, and the control device is used when the fuel oil level drops below the level of the fuel weight receiving portion of the piezoelectric element. Since the fuel oil level estimated based on the integrated value of the valve opening time of the fuel injection valve after the fuel injection valve has dropped below the level is displayed on the oil level display device, the piezoelectric element is placed in the fuel tank of the housing. If the fuel oil level drops below the level of the fuel weight receiving portion of the piezoelectric element even if it is placed in the overhanging portion of the fuel oil level, the lowered fuel oil level is based on the integrated value of the valve opening time of the fuel injection valve. It can be estimated and displayed on the oil level display device. As a result, the fuel oil level that has dropped below the above level can be accurately detected and displayed. Further, if the piezoelectric element can be arranged at a relatively high portion of the overhanging portion, it is less likely to be restricted in arrangement and the piezoelectric element can be installed in the housing with a high degree of freedom, and even in that case, the fuel oil level can be detected. , The display can be performed without any trouble.

A vertical cross-sectional view briefly showing a main part of a fuel supply device and a peripheral device thereof according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

First, in FIG. 1, the fuel in the fuel tank T is attached to the bottom wall Tb of the fuel tank T mounted on a saddle-riding vehicle, for example, a motorcycle, with respect to the electromagnetic fuel injection valve I provided in the in-vehicle internal combustion engine. A fuel pump module FM for supplying the fuel in a pressurized state is installed.

An opening To for mounting the fuel pump module FM is formed in the bottom wall Tb of the fuel tank T, and the fuel pump module FM is mounted on the bottom wall Tb so as to close the opening To. The fuel pump module FM and the fuel injection valve I are operated and controlled according to the operating state of the internal combustion engine by an electronic control device C arranged at an appropriate position on the vehicle body outside the fuel tank T.

The fuel pump module FM is arranged in the fuel tank T and is fixed to the pump unit U as a fuel pump for sucking and discharging the fuel in the fuel tank T and the bottom wall Tb of the fuel tank T to close the opening To. A fuel outlet pipe that is partially projected into the fuel tank T to hold the fuel pump U and a fuel outlet pipe that is projected from the lower outer surface of the housing 10 and can be connected to a fuel pipe connected to the fuel injection valve I. 11o, a communication passage 20 formed in the wall of the housing 10 and communicating the fuel discharge portion Uo of the fuel pump U to the fuel outlet pipe 11o, and when the fuel pressure in the communication passage 20 exceeds a predetermined value, the fuel of the communication passage 20 It includes a regulator R held in the housing 10 to return a part of the fuel to the inside of the fuel tank T, and an oil level sensor S for detecting the fuel oil level L in the fuel tank T.

In the present embodiment, the pump unit U houses a motor unit (not shown) and a pump unit driven by the motor unit in a cylindrical unit housing Uc arranged horizontally along the tank bottom wall Tb. Is composed of.

Although the housing 10 has a simplified cross-sectional display in FIG. 1, it actually has a housing element divided into at least two, for example, a lid portion that closes the opening To and is fixed to the tank bottom wall Tb. The lower housing 11 is divided into an upper housing 12 that projects into the fuel tank T and supports the pump unit U. The lower housing 11 and the upper housing 12 are connected to each other by means of joining (welding, bolting, snap-fit joining means, press-fitting means, etc.) (not shown). Although not shown, the upper housing 12 may be further divided into at least two members, if necessary, and the upper housing 12 may be detachably connected to each other.

Between the annular flange portion 11f of the lower housing 11 and the lower surface of the bottom wall Tb of the fuel tank T, an annular sealing member 15 that oil-tightly seals the space between the annular collar portion 11f and a coupling means (not shown) that detachably connects the two. For example, bolts and weld nuts) are provided. An annular sealing member that oil-tightly seals the joint surface between the upper housing 12 and the lower housing 11 and surrounds the communication passage 20 is also interposed.

Further, a coupler portion 11c that can be connected to the external wiring connected to the electronic control device C is integrally formed on the outer peripheral wall portion of the lower housing 11. The connection terminal (not shown) of the coupler portion 11c is connected to the motor portion of the pump unit U and the oil level sensor S.

The filter 30 is configured by accommodating the filter medium in a flexible outer skin formed of, for example, a flat bag shape of a net material, and the inside of the filter medium is connected to the fuel suction portion Ui of the pump unit U. Therefore, when the pump unit U operates, the fuel in the fuel tank T is filtered by the filter 30, and then sucked from the fuel suction portion Ui into the pump portion in the unit housing Uc.

By the way, the oil level sensor S is composed of a piezoelectric element S fixed to a protruding portion (that is, the upper housing 12) of the housing 10 into the fuel tank T and immersed in the fuel in the fuel tank T. .. The piezoelectric element S is configured by exposing and holding a pressure receiving portion Sa that receives the fuel weight above this as pressure on the upper surface of the element main body Sm. Thus, the pressure receiving portion Sa is an example of the fuel weight receiving portion in the piezoelectric element S.

Then, the element body Sm detects the stress or slight deformation of the pressure receiving portion Sa generated in response to the pressure received by the pressure receiving portion Sa, and detects an electric detection signal (for example, voltage) corresponding to the pressure (the fuel weight). The signal) can be output to the electronic control device C.

By the way, the pressure received by the pressure receiving portion Sa of the piezoelectric element S corresponds to the weight of the fuel directly above, and it is considered that this has a linear relationship with the fuel oil level L in the fuel tank T. Therefore, if the correlation between the detection signal output by the piezoelectric element S corresponding to the pressure (fuel weight) received by the pressure receiving unit Sa and the actual fuel oil level L is investigated in advance and stored in the electronic control device C. When the detection signal output by the piezoelectric element S corresponding to the pressure (fuel weight) received by the pressure receiving unit Sa is sent to the electronic control device C, the electronic control device C stores the detection signal and the correlation. The fuel oil level L can be estimated based on the information. Then, based on the estimation result, the electronic control device C outputs a display command signal for displaying the fuel oil level L on the oil level display device M outside the fuel tank T.

The oil level display device M is arranged at an appropriate position (for example, in an instrument panel) of the vehicle body visible to the driver as a fuel gauge with a display screen for notifying the driver of the fuel oil level L.

Further, when the fuel oil level L in the fuel tank T drops below the level Lm of the pressure receiving portion Sa of the piezoelectric element S, the fuel weight does not act on the pressure receiving portion Sa, so that it becomes difficult for the piezoelectric element S to detect the oil level. .. The level Lm of the pressure receiving portion Sa exists at an intermediate height between the upper limit level Lf and the lower limit level Le of the fuel oil level L in the fuel tank T.

Therefore, in the electronic control device C, when the fuel oil level L drops to the level Lm or less of the pressure receiving portion Sa of the piezoelectric element S, the integrated value of the valve opening time of the fuel injection valve I after the fuel oil level L drops to the level Lm or less. It has a function of estimating and calculating the fuel oil level L based on the above.

That is, the electronic control device C originally has a function of outputting a valve opening command signal to the fuel injection valve I according to the operating state of the internal combustion engine, and the fuel injection valve I of the fuel injection valve I is based on the valve opening command signal. The valve opening time can be integrated. On the other hand, the valve opening time and the fuel injection amount (hence, fuel consumption amount) are considered to have a linear relationship.

Therefore, if the correlation between the integrated value of the valve opening time and the fuel oil level L in the fuel tank T is investigated in advance and stored in the electronic control device C, the fuel oil level L is the level Lm of the pressure receiving portion Sa. When it decreases below, the fuel oil level L can be estimated based on the integrated value of the valve opening time of the fuel injection valve I after the decrease. Then, based on the estimation result, the electronic control device C outputs a display command signal for displaying the fuel oil level L on the oil level display device M.

Next, the operation of the embodiment will be described.

In the fuel pump module FM, when the motor portion of the pump unit U is energized according to the operating state of the internal combustion engine, the fuel in the fuel tank T is filtered by the filter 30, and then the pump unit is sent from the fuel suction portion Ui. It is sucked into the pump part in U. Then, the fuel pressurized by the pump section and discharged from the fuel discharge section Uo reaches the fuel outlet pipe 11o through the oil hole 20 in the housing 10, and is supplied to the fuel injection valve I from there via the external pipe. Will be done.

Thus, during the operation of the internal combustion engine, the electronic control device C outputs signals for operating and controlling various devices necessary for the operation of the internal combustion engine, and also outputs various information related to the operating status of the internal combustion engine. Receives detection signals from various detectable sensors. The device also includes a fuel injection valve I and a motor unit of the fuel pump module FM, and the sensor also includes a piezoelectric element S as an oil level sensor.

Further, the oil level sensor of the present embodiment is composed of a piezoelectric element S fixed to a projecting portion (upper housing 12) of the housing 10 into the fuel tank T and immersed in the fuel in the fuel tank T. The piezoelectric element S outputs an electrical detection signal corresponding to the fuel weight above the piezoelectric element S to the electronic control device C. Then, since the electronic control device C causes the oil level display device M to display the fuel oil level L based on the detection signal of the piezoelectric element S, the oil level display device M can display the fuel even if the piezoelectric element S is used as the oil level sensor. The oil level L can be displayed sequentially.

Moreover, the piezoelectric element S serving as the oil level sensor does not have a movable portion that moves significantly in the fuel tank T, and is simply fixed to the overhanging portion (upper housing 12) of the housing 10 into the fuel tank T. As compared with the conventional oil level sensor structure having a float and a long swing arm, the oil level sensor has been sufficiently miniaturized, which in turn contributes to the miniaturization of the fuel pump module FM with an oil level sensor. can do. Further, as the size of the fuel pump module FM is reduced, the workability of assembling the fuel pump module FM to the fuel tank T is improved.

Further, when the fuel oil level L in the fuel tank T drops below the level Lm of the pressure receiving portion Sa of the piezoelectric element S, the fuel weight does not act on the pressure receiving portion Sa, so that it becomes difficult for the piezoelectric element S to detect the oil level. .. That is, the oil level can be detected by the piezoelectric element S only when the fuel oil level L in the fuel tank T is in the range from the upper limit level Lf to the level Lm of the pressure receiving portion Sa.

Therefore, when the fuel oil level L drops below the level Lm of the fuel weight receiving portion of the piezoelectric element S, the electronic control device C integrates the valve opening time of the fuel injection valve I after the level drops below the level Lm. The fuel oil level L estimated based on the value is displayed on the oil level display device M. Therefore, even if the piezoelectric element S is arranged in the overhanging portion of the housing 10 into the fuel tank T (the top of the upper housing 12 in the embodiment), the fuel oil level L drops below the level Lm. However, the lowered fuel oil level L can be accurately displayed on the oil level display device M.

As a result, even the fuel oil level L of the level Lm or less can be accurately detected and displayed. Further, if the piezoelectric element S can be arranged in a relatively high portion of the upper housing 12 as in the embodiment, the piezoelectric element S can be arranged in the housing 10 with a high degree of freedom without being restricted by the arrangement. However, even in that case, the fuel oil level L can be detected and displayed without any trouble.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes are made without departing from the present invention described in the claims. Is possible.

For example, in the above-described embodiment, the piezoelectric element S as an oil level sensor is arranged on the top of the overhanging portion (that is, the upper housing 12) of the housing 10 into the fuel tank T. The arrangement portion of S is not limited to the embodiment, and for example, the piezoelectric element S may be arranged in the lower housing 11, or may be arranged on the side or bottom of the overhanging portion (that is, the upper housing 12). It may be installed.

Further, in the above embodiment, the first function is that the electronic control device C as the control device of the present invention outputs a display command signal for displaying the fuel oil level to the oil level display device M based on the detection signal of the piezoelectric element S. Or, when the fuel oil level drops below the level Lm of the pressure receiving portion Sa of the piezoelectric element S, the fuel oil estimated based on the integrated value of the valve opening time of the fuel injection valve I after the level drops below the level Lm. It has a second function to output a display command signal to display the surface, but not only those first and second functions, but also other equipment (that is, fuel injection) necessary for operating the internal combustion engine according to the operating condition of the internal combustion engine. Examples of devices having a function of controlling a valve I, a piezoelectric element S, and a device other than the oil level display device M) have been illustrated. However, the control device of the present invention is not limited to the embodiment, and for example, a dedicated control device that fulfills only the first and second functions may be used.

Further, in the above embodiment, the electronic control device C as the control device of the present invention is provided at an appropriate position on the vehicle body outside the fuel tank, but the arrangement portion thereof is not limited to the embodiment, for example, the fuel pump module. It may be deployed in the housing 10 of the FM or the peripheral portion of the fuel tank T.

Further, in the above embodiment, the pump unit U as a fuel pump is of a horizontal type in which the central axis X extends in a substantially horizontal direction along the tank bottom wall Tb. However, in the present invention, the pump unit U is used. A vertical type may be used in which the central axis is substantially vertical.

Further, in the above-described embodiment, the oil level display device M using a device dedicated to the oil level display (that is, an oil level gauge) is shown, but a general-purpose display device capable of displaying information other than the oil level display is used. It may be used as an oil level display device.

C ... Electronic control device as a control device FM ... Fuel pump module as a fuel supply device I ... Fuel injection valve L ... Fuel oil level Lm in the fuel tank ... ... Level M of the pressure receiving part as the fuel weight receiving part ..... Oil level display device S ....・ ・ ・ ・ ・ Fuel tank Tb ・ ・ ・ ・ Bottom wall To ・ ・ ・ ・ Opening U ・ ・ ・ ・ ・ Pump unit Uo as a fuel pump ・ ・ ・ ・ Fuel discharge part X ・ ・ ・ ・ ・ Central axis 11 ··········································································································

Claims (2)

A fuel pump (U) arranged in the fuel tank (T) to suck and discharge the fuel in the fuel tank (T) and a fuel pump (U) fixed to the bottom of the fuel tank (T) to close the opening (To) at the bottom. At the same time, a part of the fuel is projected into the fuel tank (T) to hold the fuel pump (U), and the housing (10) is projected from the lower outer surface of the housing (10) to inject fuel for an internal combustion engine. A fuel outlet pipe (11o) that can be connected to a fuel pipe connected to a valve (I) and a fuel discharge portion (Uo) of the fuel pump (U) formed in the wall of the housing (10) are connected to the fuel outlet. In a fuel supply device for an internal combustion engine provided with a communication passage (20) communicating with a pipe (11o) and an oil level sensor (S) for detecting a fuel oil level (L) in a fuel tank (T).
The oil level sensor is composed of a piezoelectric element (S) fixed to the housing (10) and immersed in the fuel in the fuel tank (T).
The piezoelectric element (S) outputs an electrical detection signal corresponding to the fuel weight above the piezoelectric element (S) to the control device (C), and the control device (C) sends the detection signal to the detection signal. A fuel supply device for an internal combustion engine, characterized in that the fuel oil level (L) is displayed on the oil level display device (M) based on the above. The piezoelectric element (S) is fixed to the overhanging portion (12) of the housing (10) into the fuel tank (T).
When the fuel oil level (L) drops below the level (Lm) of the fuel weight receiving portion (Sa) of the piezoelectric element (S), the control device (C) falls below the level (Lm). The claim is characterized in that the fuel oil level (L) estimated based on the integrated value of the valve opening time of the fuel injection valve (I) after the decrease is displayed on the oil level display device (M). The fuel supply device for an internal combustion engine according to 1.

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