KR20190098422A - Fuel pump driving device - Google Patents

Abstract

The present invention relates to a fuel pump driving device, which measures the current of a mounted element before calculating the current value required for monitoring and controlling to control the driving of a motor without mounting an additional sensor, thereby reducing fabrication costs by decreasing the circuit complexity and number of components. To this end, the fuel pump driving device of the present invention comprises: a pump supplying fuel stored in a fuel tank to an engine; a motor supplying driving force for the operation of the pump; and a driving device electrically connected to the motor, controlling the driving of the motor such that the fuel may be supplied to the engine as requested by an electronic control unit, and having a plurality of electric elements for the control thereof. Here, the driving device is characterized by detecting a current flowing in one electric element among the plurality of electric elements to monitor the state of the motor.

Description

Fuel Pump Drive Unit {FUEL PUMP DRIVING DEVICE}

The present invention relates to a driving device of a fuel pump, in particular, by measuring the current of the device mounted to control the motor drive without mounting a separate sensor to calculate the current value for monitoring and control, thereby reducing the complexity of the circuit It relates to a driving device of a fuel pump which enables to lower the manufacturing cost by reducing the number of parts.

In automobiles using fuels such as gas, gasoline, and diesel, fuel stored in a fuel tank is supplied to an engine by using a fuel pump. In the fuel pump, the rotational speed of the pump is electronically controlled to adjust the amount of fuel supplied to the engine. For this purpose, an electric motor is used to drive a fuel pump, and a DC motor such as a brushless DC motor is generally used to secure high efficiency and long life reliability.

The control circuit is configured to perform such functions as controlling the motor, measuring the fuel amount, and providing monitoring information of the fuel pump. Recently, a control circuit is coupled to a pump and used in the form of a pump module.

The control circuit of such a fuel pump includes various electrical elements, such as microcontrollers, integrated circuit elements, field effect transistors, and electrolytic capacitors, for the construction of voltage regulators, diagnostic circuits, and motor control circuits on printed circuit boards. Are mounted and configured.

Conventionally, both sides of a printed circuit board are used to mount such devices in a narrow space, but there is still a space limitation, which acts as a factor that lowers design freedom.

In addition, in automobile production, reduction of production cost, maintenance and management cost reduction, and miniaturization are steady targets, and there is a demand for a method for reducing such costs in components such as fuel pumps.

Korean Patent Registration No. 10-1164419 (July 12, 2012 announcement)

Accordingly, an object of the present invention is to measure the current of the device mounted to control the motor drive without mounting a separate sensor to calculate the current value required for monitoring and control, thereby reducing the complexity of the circuit and reducing the number of components It is to provide a fuel pump driving device that enables a reduction in manufacturing cost.

In order to achieve the above object, a fuel pump driving apparatus according to the present invention includes a pump for supplying fuel stored in a fuel tank to an engine; A motor providing power for operation of the pump; And a driving device electrically connected to the motor and controlling driving of the motor so that fuel is supplied to an engine at the request of an electronic control unit, the driving device having a plurality of electric elements for the control. The driving device is characterized in that for detecting the current flowing in any one of a plurality of electrical elements to monitor the state of the motor.

The plurality of electric elements includes a transistor module including a transistor for generating a control signal for driving control of the motor and a gate driver for controlling a switching operation of the transistor; And a micro control unit for controlling the operation of the transistor module.

The micro control unit is connected to a diagnostic terminal of the transistor module to obtain a current value flowing through the transistor.

The micro control unit is characterized by substituting the current value into a correction equation calculated in advance, calculating a correction current value, and using the correction current value for the monitoring.

The correction equation is characterized by multiplying the current value by a value obtained by dividing the change rate of the transistor internal terminal current by the change rate of the current actually applied to the transistor, and adding the offset current value of the internal terminal.

The correction equation is characterized in that the correction is performed so that the error rate of the monitoring result predicted by the current value is equal to or less than a predetermined ratio even if the duty of the control signal or the magnitude of the voltage applied to the motor changes.

Fuel pump driving apparatus according to the present invention by measuring the current of the device mounted to control the motor drive without mounting a separate sensor to calculate the current value required for monitoring and control, reducing the complexity of the circuit and the number of parts It is possible to reduce the manufacturing cost.

1 is a perspective view of the fuel pump drive unit and the fuel pump flange combined.
2 is a partial perspective view of a fuel pump drive and a fuel pump flange;
3 is a perspective view showing a first surface of a drive device;
4 is a perspective view showing a second surface of the drive device;
5 is an exemplary view for explaining a current value calculation method by a driving device.
6 is an exemplary diagram showing error rates before and after correction of the current flowing in the FET;

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. In the accompanying drawings, it should be noted that the same reference numerals are used in the drawings to designate the same configuration in other drawings as much as possible. In addition, in describing the present invention, when it is determined that a detailed description of a related known function or known configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Some features shown in the drawings are enlarged, reduced, or simplified for ease of description, and the drawings and their components are not necessarily drawn to scale. However, those skilled in the art will readily understand these details.

1 is a view illustrating a coupling form of a fuel pump driving device and a fuel pump according to the present invention. FIG. 1 is a perspective view of a fuel pump driving device and a fuel pump flange, and FIG. 2 is a fuel pump driving. Partial perspective view of the device and fuel pump flange.

1 and 2, the fuel pump includes a housing 20 provided on the flange 11, a cover 30 coupled to the housing 20 to form an accommodation space in the housing 20, and the flange. A multi-valve 12 is provided at one side of 11, and a driving device for driving a fuel pump is stored in the storage space.

The flange 11 is formed in a plate shape as shown as a portion mounted to a fuel tank, that is, a cylinder (not shown) in which fuel of an automobile is stored. One side surface of the flange 11 is provided with a multi-valve 12 for selectively blocking the fuel supplied to the engine by the fuel pump.

The housing 20 is provided on an upper surface of one side of the flange 11 and is formed in a container shape in which one side is opened to form an accommodation space. The cover 30 is coupled to cover the opening of the housing 20 to accommodate the driving device 50 in an accommodation space provided therein. The opening of the housing 20 is formed with a fixing hole to which the fixing bolt is coupled and fixed for coupling with the cover 30.

A plurality of second terminals 14 are provided inside the housing 20 to electrically connect the driving device 50 to an external power source or device, and the second terminal 14 has a connector portion 40. And electrically connected to the first terminal 16 provided at 60. The first terminal 16 and the second terminal 14, which are electrically connected, are integrally formed and installed to penetrate the housing 20 or the flange 11, and one side is exposed to the outside from the connector parts 40 and 60. It may be configured to.

The housing 20 and the cover 30 may be formed using a metal or a synthetic resin such as aluminum having excellent mechanical properties and chemical resistance.

One side of the housing 20 is provided with a first connector portion 40 as shown, for example, it can be used for the purpose of being combined with the socket of the power supply for supplying external power. Separately, a second connector 60 for electrically connecting the sensor and the driving device installed inside the cylinder may be provided at the lower surface of the flange through the lower end of the housing 20.

The cover 30 is coupled to the opening of the housing 20 to form a space for accommodating the driving device 50 together with the housing 20. To this end, the cover 30 may be formed in the shape of an ellipse or a square plate having a shape corresponding to the opening of the housing 20, and a plurality of fixing holes 13 through which the fixing bolts 16 are coupled may be formed in the edge portion. have.

The driving device 50 is composed of a printed circuit board and a plurality of electric elements mounted on the printed circuit board, and is housed in the housing 20. At this time, the driving device 50 is electrically connected to the second terminal 14 provided in the housing 20, and via the second terminal 14, the first connector 40 or the second connector unit ( 60) to an external or other device such as a sensor. Through this, the driving device 50 receives power and control commands supplied from the connector parts 40 and 60 from the outside, and supplies a control signal for controlling the control object to the external device. In particular, the driving device 50 monitors the operation of the fuel pump and transmits the monitoring result to the electronic control unit (not shown). Specifically, the driving device 50 measures the current value of one of the electric elements without using a current sensor for the current value according to the driving of the fuel pump. Then, the driving device 50 transmits the measured current value to the electronic control unit or processes according to a predetermined procedure to determine the current state and transmits the determination result to the electronic control unit. To this end, the driving device 50 reduces the error by correcting the current value measured from the electric element by a correction value previously determined experimentally, and transmits the corrected current value to the electronic control unit, or uses the current state to You will be judged. This drive device 50 will be described in more detail with reference to the separate drawings below.

3 and 4 are exemplary views showing a driving device of the fuel pump according to the present invention, FIG. 3 is a perspective view showing a first surface of the driving device, and FIG. 4 shows a second surface of the driving device. This is an illustrative example.

3 and 4, the driving device 50 transmits data from a sensor installed inside the bomb to an electronic control unit (ECU, not shown) of the vehicle, or according to a control signal transmitted from the electronic control unit. The driving power is supplied to the motor to control the fuel pump to supply fuel to the engine.

The driving device 50 generates a pulse width modulation (PWM) signal for driving the motor, and adjusts the supply amount of fuel through the adjustment of the PWM signal. The driving device 50 generates various PWM signals, controls the operating speed of the motor, diagnoses the pump condition, controls the proportional integral for accurate operation according to the control signal, and regulates the stable voltage supply to the motor. do.

To this end, the driving device 50 includes a printed circuit board 51 and a plurality of electric elements mounted on the printed circuit board 51.

A conductive pattern is formed on each of the first surface 51a and the second surface 51b of the printed circuit board 51, and the electrical elements are coupled to each other so as to be electrically connected to the conductive pattern (not shown). When the printed circuit board 51 is accommodated in the housing 20, a plurality of terminal holes 60 are provided to correspond to the position of the second terminal 14 so as to be electrically coupled to the second terminal 14. do. The terminal hole 60 is connected to the electric element by a conductive pattern. As illustrated, the printed circuit board 51 has conductive patterns formed on both surfaces 51a and 51b of the circuit board, and electrical elements are also mounted on both surfaces 51a and 51b. Here, the printed circuit board may be a multilayer board (MLB), but the present invention is not limited thereto.

The electric element includes a microcontrol unit 52 (MCU) performing the above-described control function, a communication module 56 for communication with an external device including an electronic control unit, a transistor module (FET) 54 for PWM control, Electrolytic capacitor 58, regulator 66 for stable power supply, filter 64 for preventing generation of electromagnetic waves or disturbance caused by electromagnetic waves, bus terminal electrically contacting cover 30 to secure ground voltage And 68.

In particular, the microcontrol unit 52 (MCU) controls the motor to operate the pump as intended by the electronic control unit of the vehicle, and collects and transmits monitoring information for confirming the state of the pump to the electronic control unit, The monitoring is performed by itself and the result is transmitted to the electronic control unit.

To this end, the micro control unit 52 (MCU) measures the value of the current flowing in the driving device 50 according to the operation of the pump, and determines the current state of the fuel pump based on the value of the current. In particular, the micro control unit 52 (MCU) calculates the measured current value as a correction current value corrected according to a correction equation that is experimentally calculated and stored in advance, and determines the current state based on the correction current value, To the electronic control unit. This will be described in more detail with reference to the other drawings below.

Such electrical elements may be divided and disposed on the first surface 51a or the second surface 52b of the printed circuit board 51 according to the designer's intention. For example, in FIGS. 3 and 4, the microcontrol unit 52, the communication module 56, the transistor module 54, and the electrolytic capacitor 58 are disposed on the first surface, and the regulator 66 and the filter are disposed on the second surface. An example is shown where 64 and bus terminal 68 are configured, but this is not intended to limit the invention as presented by way of example.

FIG. 5 is an exemplary diagram for describing a method of calculating a current value by a driving apparatus, and FIG. 6 is an exemplary diagram illustrating an error rate before and after correction of a current flowing in a FET.

5 and 6, in order to determine the driving state of the fuel pump and control the fuel supply amount, the electronic control unit of the vehicle supplies a control signal to the driving device 50 of the fuel pump and requests information for monitoring. Done.

In response to the request of the electronic control unit, the driving device 50 supplies a control signal for driving the motor, for example, a PWM signal, to drive the motor according to the control signal.

In addition, the driving device 50 measures the current required to drive the motor, and transmits the current measurement value to the electronic control unit, or judges whether the motor performs normal driving by judging the current measurement value according to predetermined criteria and procedures. Done.

To this end, the conventional fuel pump constitutes a current sensor (or ammeter) for measuring the amount of current supplied to the motor, and collects the value of the current sensor and used it as data for monitoring. However, in the present invention, the measured current is used as data for monitoring by measuring the current of the transistor module 54 of the electric elements used to supply power to the motor.

Specifically, the transistor module 54 may be used to generate a PWM signal, and includes a plurality of FET devices and a gate driver for applying voltages to gates of the FET devices. This gate driver is provided with a diagnosis terminal (Fault Diagnosis) that can check the current value, the micro control unit 52 is connected to the transistor module 54 through this diagnostic terminal to measure the current value flowing through the FET .

The micro control unit 52 corrects this when the current value is measured in the transistor module 54 through the diagnostic terminal. Here, the correction may be performed in the electronic control unit of the vehicle, but for the convenience of description, the description will be made on the assumption that the correction is performed in the micro control unit 52.

A correction equation for the correction of the current value is obtained experimentally.

In step 1, power is supplied to the gate without supplying current to the FET. In this case, an Is offset value is calculated by measuring a current value flowing through the source terminal. At this time, since no current is supplied to the FET, Iout = 0A flowing through the drain terminal is obtained.

In step 2 the FET supplies a constant current, for example 4.5 A and powers the gate. At this time, the value of Is; 4.5A is calculated by measuring the current flowing through the source terminal.

In step 3, the slope of the current output line of FIG. 5 is calculated using the values calculated in steps 1 and 2, where the slope is expressed by Equation 1 below.

In step 4, the correction equation is calculated by applying the slope calculated in step 3, and the correction equation is shown in Equation 2 below.

In step 5, the calculated current correction equation is programmed into the micro control unit 52. Since the micro control unit 52 can calculate the current value only by measuring the value of Iout through the diagnostic terminal, it is possible to calculate the current used to drive the motor without a separate current sensor, for monitoring this It can be used as a current value to monitor the operation of the fuel pump.

On the other hand, in the related art, as shown in the graph of <Previous Product> of FIG. 6, since the current value measured in the FET has a large variation in the error rate according to the duty and shows an error rate of up to 24%, a separate current sensor is provided in the driving device. The current value was measured by constructing a circuit via the current sensor.

However, in the present invention, the error rate is lowered as shown in Fig. 6 (graph at the bottom of Fig. 6) by correcting the current value using a correction equation without using a current sensor. 6, the error rate is maintained at 10% or less even when the duty of the control signal changes, and the error rate is maintained at 10% or less even when various voltages (8V to 20V) are used. . This is possible because the correction formula for calculating the current value is experimentally calculated to reflect the characteristics of each electric element. In particular, the current value calculated by such a correction formula is reliable, unlike the conventional (existing product) because the error rate is maintained at less than 10% even when the duty and control voltage of the control signal is different.

Although illustrated and described in detail as a specific example to illustrate the technical idea of the present invention, the present invention is not limited to the same configuration and operation as the specific embodiment as described above, as many variations are within the scope of the present invention. It can be carried out in. Therefore, such modifications should also be regarded as belonging to the scope of the present invention, and the scope of the present invention should be determined by the claims below.

11 flange 12 multi-valve
13: fixing hole 14: Terminal 2
16: fixing bolt 20: housing
30: cover 40, 60: connector
41: terminal 1 50: drive device
51: printed circuit board 52: micro control unit
54: transistor 56: communication module
60: terminal hall

Claims (6)

A pump for supplying fuel stored in the fuel tank to the engine;
A motor providing power for operation of the pump; And
And a driving device electrically connected to the motor and controlling the driving of the motor so that fuel is supplied to the engine at the request of the electronic control unit, and having a plurality of electric elements for the control.
The driving device is a fuel pump driving device, characterized in that for detecting the current flowing in any one of a plurality of electrical devices to monitor the state of the motor. The method of claim 1,
The plurality of electrical elements
A transistor module including a transistor for generating a control signal for driving control of the motor and a gate driver for controlling a switching operation of the transistor;
And a micro control unit for controlling the operation of the transistor module. The method of claim 2,
The micro control unit
And a fuel pump driving device connected to the diagnostic terminal of the transistor module to obtain a current value flowing through the transistor. The method of claim 3, wherein
And the micro control unit calculates a correction current value by substituting the current value into a correction equation calculated in advance, and uses the correction current value for the monitoring. The method of claim 4, wherein
The correction formula is
And a value obtained by dividing the change rate of the transistor internal terminal current by the change rate of the current actually applied to the transistor, multiplied by the current value, and adding the offset current value of the internal terminal. The method of claim 4, wherein
The correction formula is
The error rate of the monitoring result predicted by the current value is
The fuel pump driving apparatus, characterized in that the correction is to be equal to or less than a predetermined ratio even if the duty of the control signal or the magnitude of the voltage applied to the motor changes.

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