AU2011201131A1

AU2011201131A1 - Apparatus and Method for Controlling Fuel Pump Motor

Info

Publication number: AU2011201131A1
Application number: AU2011201131A
Authority: AU
Inventors: Hyung Soo Kim; Jung Dae Kim
Original assignee: Motonic Corp
Current assignee: Motonic Corp
Priority date: 2010-12-06
Filing date: 2011-03-14
Publication date: 2012-06-21
Also published as: KR20120062108A; KR101164419B1

Abstract

Disclosed are an apparatus and a method for controlling a fuel pump motor. The apparatus includes a motor driving unit for driving the fuel pump motor, a detection unit for detecting 5 a driving state of the fuel pump motor, a valve driving unit for driving the fuel cut solenoid valve, a controller for controlling the driving of the motor driving unit and the valve driving unit, and a power converter for converting a supply voltage into a logic voltage, which is required to drive the 10 controller and in the motor driving unit, and a driving voltage required to drive the motor and the fuel cut solenoid valve. The valve driving unit includes a valve driver for driving the fuel cut solenoid valve and a gate driver for converting a level of an FET driving signal into a voltage level of the driving 15 voltage of driving a motor driver. Ob,< 0 <0 -0 Cl4. En. k)

Description

APPARATUS AND METHOD FOR CONTROLLING FUEL PUMP MOTOR BACKGROUND OF THE INVENTION 1. Field of the invention 5 The present invention relates to an apparatus and a method for controlling a fuel pumpmotor. More particularly, the present invention relates to an apparatus and a method for controlling a fuel pump motor while controlling a fuel cut solenoid valve which is installed on a fuel supply line of a gas fuel vehicle 10 and perform an opening/closing operation to selectively supply gas fuel. 2. Description of the Related Art In generally, in a gas fuel vehicle, gas fuel stored in a fuel tank is supplied to an engine by a fuel pump. 15 In this case, the rotational speed of the fuel pump is controlled by taking the speed of the vehicle into consideration, so that an amount of gas supplied to the engine can be adjusted. In order to ensure high efficiency, a long life span, and reliability, a brushless DC motor is used to drive the fuel pump. 20 Especially, a sensorless BLDC motor is generally used. Recently, many researches and studies have been performed to improve the fuel efficiency of a vehicle. Applicant of the present invention has received a patent right with Korean Patent Registration No. 10-0649355 issued on 25 November 27, 2006 (hereinafter, referred to as "patent document 1") disclosing a technology for a driving apparatus of a fuel pump motor capable of improving the fuel efficiency of a vehicle by precisely controlling the rotational speed of the fuel pump motor. 5 FIG. 1 is a block diagram showing a driving apparatus of a fuel pump motor according to patent document 1. As shown in FIG. 1, the driving apparatus 4 of the fuel pump motor according to patent document 1 includes a motor driver 5 for driving a motor 1 to rotate a fuel pump by using power 10 supplied from a power source 2 , a motor controller 7 for detectinq the position (angle) of a rotor of the motor 1 and a current supplied to the motor 1 through themotor driver 5 and transmitting a switching signal necessary for the switching operation of an FET device provided in the motor driver 5, a gate driver 6 for 15 turning on/off a gate of the FET device according to the switching signalofthemotorcontroller 7 , andacontroller8 foroutputting a PWM (Pulse Width Modulation ) control signal of a duty value, which is set based on the comparison result of the driving speed of the vehicle from an ECU 3 through an interface 9 and the data 20 about the rotational speed of the motor 1 delivered from the motor controller 7. The driving apparatus of the fuel pump motor according to patent document 1 disclosing the structure directly switches the power supply voltage of the vehicle to drive the fuel pump 25 motor, so that the rotation speed of the fuel pump motor can be precisely controlled. However, patent document 1 has a limitation in improving the fuel efficiency of the vehicle only by precisely controlling the driving of the fuel pump motor. 5 Therefore, researches and studies have been performed to develop a technology of finding conditions exerting an influence on the fuel efficiency of the vehicle and controlling the conditions. For example, a fuel cut solenoid valve is installed in 10 a gas fuel vehicle with a liqiefied petroleum injection scheme to directly inject gas fuel having a liquid state to an engine, so that the fuel cut solenoid valve opens or closes a fuel supply line to supply gas fuel pumped by a fuel pump to the engine. An ECU generates a driving signal to drive a relay according 15 to the turn-on state of an ignition key, and the fuel cut solenoid valve lifts an internal plunger by using a supply voltage from a battery through the relay driven by the driving signal. Therefore, sincetheignitionkeyisalwaysturnedonduring the driving of the vehicle, the fuel cut solenoid valve 20 continuously receives the supply voltage from the battery and is maintained at a driving state. As a result, the temperature of the fuel cut solenoid valve is increased. In this case, according to the experiment to measure the temperature, the temperature of the fuel cut solenoid valve is increased to about 25 85"C Therefore, if the temperature of the fuel cut solenoid valve is increased, the temperature of the fuel supply line is increased, so that the gas fuel in a liquid state supplied to the engine through the fuel supply line is changed into a gas 5 state. Accordingly, gas bubbles are generated, a fuel pressure is increased, and the viscosity of the gas fuel is changed. Accordingly, the driving apparatus of the fuel pump motor equipped with the fuel cut solenoid valve according to the related art cannot precisely control an amount of fuel injected from in an injector, so that an amount of consumed fue] is increased, and the fuel efficiency can be degraded. CITED REFERENCE Patent Document 1: Korean Patent Registration No. 15 10-0649355 (issued on November 27, 2006). SUMMARY OF THE INVENTION In order to solve the problems of the related art, an object of the present invention is to provide an apparatus and a method 20 for controlling a fuel pump motor, capable of controlling the driving of a fuel pump motor and reducing the voltage applied to a fuel cut solenoid valve, thereby preventing the temperature of the fuel cut solenoid valve from being raised. Another object of the present invention is to provide an 25 apparatus and a method for controlling a fuel pump motor, capable of precisely controlling an amount of fuel supplied to an engine of a gas fuel vehicle. In order to accomplish the above objects, there is provided an apparatus for controlling a fuel pump motor to control driving 5 of the fuel pump motor and driving of a fuel cut solenoid valve installed in a fuel supply line of supplying fuel pumped by a fuel pump to an engine. The apparatus includes a motor driving unit for driving the fuel pump motor, a detection unit for detecting a driving state of the fuel pump motor, a valve driving 10 unit for driving the fue] cut solenoid valve, a controller for controlling the driving of the motor driving unit and the valve driving unit based on a driving signal received from an ECU of a vehicle and a detecting result of the detection unit, and a powerconverterforconvertingasupplyvoltage, whichissupplied 15 from a power supply of the vehicle, into a logic voltage, which is required to drive the controller and in the motor driving unit, and a driving voltage required to drive the motor and the fuel cut solenoid valve. The valve driving unit includes a valve driver for driving the fuel cut solenoid valve by switching the 20 driving voltage, and a gate driver for converting a level of an FET driving signal delivered from the controller into a voltage level of the driving voltage of driving a motor driver to transmit the driving voltage to the valve driver. The valve driver includes a first FET device, and the gate 25 driver converts the FET driving signal having a level of the logic voltage into a level of the driving voltage and applies the driving voltage to a gate terminal of the first FET device. The apparatus further includes a voltage detector to detect the driving voltage. The controller changes and sets a PWM duty 5 value of the FET driving signal such that the driving voltage detected in the voltage detector is maintained to a preset turn-on maintaining voltage of the FET device if a preset initial driving time elapses after the fuel cut solenoid valve is driven. The motor driving unit includes a motor driver for driving 10 the motor by switching the driving voltage, a motor control er for generating a motor driving signal based on the duty value of the PWM control signal applied from the controller, and a second gate driver for converting and applying a voltage level of a motor driving signal into a level of the driving voltage. 15 The detection unit includes a rotor position detector for detecting the position of a rotor by using a counter electromotive signal representing phases of the motor when the motor is driven, and an overcurrent detector for detecting an overcurrrent applied to the motor to deliver the overcurrent to the controller. 20 In another aspect of the present invention, there is provided a method for controlling a fuel pump motor comprising converting a supply voltage into a logic voltage required to drive a motor driving unit and a driving voltage required to drive a fuel pump motor and a fuel cut solenoid valve, receiving 25 a speed control signal and a valve driving signal used to control driving of the fuel pump motor and the fuel cut solenoid valve from an ECU of a vehicle, controlling the driving of the fuel pumpmotor according to the speed control signal, and controlling the driving of the fuel cut solenoid valve based on the valve 5 driving signal while controlling the driving of the fuel pump motor. The controlling the driving of the fuel cut solenoid valve based on the valve driving signal while controlling the driving of the fuel pump motor includes generating an FET driving signal having the value of the logic voltage according to the valve 10 driving signal, converting the FT driving signal into a voltage level of the driving voltage to apply the FET driving signal to a gate terminal of an FET device, and opening the fuel cut solenoid valve based on the FET driving signal that has been applied to the gate terminal of the FET device. 15 The FET driving signal is set to 100% of a PWM duty value. The controlling the driving of the fuel cut solenoid valve based on the valve driving signal while controlling the driving of the fuel pump motor includes maintaining the driving voltage to a preset turn-on maintaining voltage of the FET device if 20 a preset initial driving time elapses after the fuel cut solenoid valve is driven. In the maintaining the driving voltage to the preset turn-on maintaining voltage of the FET device if the preset initial driving time elapses after the fuel cut solenoid valve is driven, 25 a PWM duty value of the FET driving signal is set to a value higher than a preset reference duty value if a level of the driving voltage detected by a voltage detector is lower than the turn-on maintaining voltage, and the PWM duty value of the FET driving signal is set to a value lower than the preset reference duty 5 value if the level of the driving voltage is higher than the turn-on maintaining voltage. The controlling the driving of the fuel pump motor according to the speed control signal includes setting a duty value of a PWM control signal according to a target RPM based on the speed 10 control signal and driving the fuel pump motor based on the duty value, detecting a position of a rotor by using counter electromotive signals represented in phases of the fuel pump motor when the motor is driven, calculating a present RPM of the motor by using the position of the rotor, changing the duty 15 value of the PWM control signal according to a difference between the present RPM and the target RPM based on the speed control signal to control the driving of the fuel pump motor, and restricting the driving of the fuel pump motor if an overcurrent is applied to the fuel pump motor during the driving of the fuel 20 pump motor. As described above, according to the present invention, if the initial driving time elapses after the fuel cut solenoid valve is turned on by using a driving voltage, the PWM duty value of the FET driving signal is changed, so that the turn-on 25 maintaining voltage lower than the driving voltage is applied to open the fuel cut solenoid valve is open. Therefore, according to the present invention, the voltage level of the driving voltage to the fuel cut solenoid valve is lowered, thereby preventing the temperature of the fuel cut 5 solenoid valve from being increased. In addition, according to the current consumption experiment, a current of about 300mA is consumed to maintain the fuel cut solenoidvalve at the open state, anamountof consumed current can be significantly reduced when comparing with about 10 1A, which is an amount of a current consumed in the driving of the valve according to the conventional scheme. Therefore, according to the present invention, the temperature of the fuel cut solenoid valve can be prevented from beingincreased, sothatthegasfuelinaliquidstateisprevented 15 from vaporized. Accordingly, an amount of gas supplied in the engine can be precisely controlled, so that the fuel efficiency of a vehicle can be improved. BRIEF DESCRIPTION OF THE DRAWINGS 20 FIG. 1 is a block diagram showing the structure of a driving apparatus of a fuel pump motor according to the related art; FIG. 2 is a block diagram showing the structure of an apparatus for controlling a fuel pump motor according to an exemplary embodiment of the present invention; and 25 FIG. 3 is a flowchart showing a method for controlling a fuel pump motor according to an exemplary embodiment of the present invention step by step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 5 Hereinafter, an apparatus and a method for controlling a fuel pump motor according to an exemplary embodiment of the present invention will be described in detail with reference to accompanying drawings. FIG. 2 is a block diagram showing the structure of an 10 apparatus for controlling a fuel pump motor according to an exemplary embodiment of the present invention. As shown in FIG. 2, the apparatus for controlling a fuel pump motor (motor) 11 according to an exemplary embodiment of thepresent invention includes a motor driving unit 20 for driving 15 the motor 11, a detection unit 30 for detecting the driving state of the motor 11, a valve driving unit 40 for driving a fuel cut solenoid valve (valve) 12 installed in a fuel supply line, and a controller 50 for controlling the driving of the motor driving unit 20 and the valve driving unit 40 based on the driving signal 20 from an ECU 13 and the detecting result of the detection unit 30. The apparatus for controlling the fuel pump motor according to an exemplary embodiment of the present invention further includes a power converter 60 for converting a supply voltage 25 of 5V, which is supplied from the battery 10 through a power supply (not shown), into a logic voltage of SV, which is required to drive the controller 50 and a motor controller 23 provided in the motor driving unit 20, and a driving voltage of about 12V required to drive the motor 11 and the valve 12. 5 Hereinafter, the present embodiment will be described by using a BLDC motor, especially, a sensorless BLDC motor as the motor 11. However, the present invention is not limited thereto. In other words, the motor 11 may include a BLDC motor with a 10 sensor. The motor driving unit 20 includes a motor driver 21 for driving the motor 11 by switching the driving voltage, the motor controller 23 for generating a motor driving signal based on the duty value of a PWM control signal applied from the controller 15 50, and a first gate driver 22 for converting a voltage level of the motor driving signal into a voltage level of a driving voltage required to drive the motor driver 21. The motor driver 21 drives in a 3-phase full bridge scheme by using a first field effect transistor (FET) and switches the 20 driving voltage of about 12V to be applied to the motor 11. The motor controller 23 generates a 3-phase motor driving signal having the level of a logic voltage supplied from the power converter 60 based on the duty value of a PWM control signal of the controller 50. 25 The first gate driver 22 converts the 3-phase motor driving signal having the logic voltage level into the voltage level of the driving voltage to drive the motor driver 21 and applies the driving signal to the first FET. The detection unit 30 includes a rotor position detector 5 31 for detecting the position of a rotor by using a counter electromotive signal representing phases (u, v, and w) of the motor 11 when the motor 11 is driven and an overcurrent detector 32 for detecting the overcurrrent applied to the motor 11 to deliver the detection signal about the overcurrent to the 10 controller 50. Therefore, the motor controller 23 delivers a tacho signal according to the position of the rotor detected in the rotor position detector 31 to the controller 50, and the controller 50 calculates a present RPM of the motor 11 based on the tacho 15 signal and changes the duty value of the PWM control signal according to the difference between the calculated RPM and a target RPM based on the speed control signal delivered from the ECU 13, thereby controlling the driving of the motor 11. In addition, if the overcurrent detector 32 detects an 20 overcurrent and delivers the detection signal to the controller 50, the controller 50 restricts the driving of the motor 11 in order to prevent the motor 11 from being damaged and malfunctioned. The valve driving unit 40 includes a valve driver 41 for 25 driving the valve 12 by switching the driving voltage anda second gate driver 42 for converting a level of an FET driving signal delivered from the controller 50 into a voltage level of the driving voltage to apply the driving voltage to the valve driver 41. 5 The valve driver 41 includes a second FET device for switching the driving voltage of about 12V applied to the valve 12. The second gate driver 42 applies the valve driving signal converted into the driving voltage to a gate terminal of the 10 second FET device. The controller 50 generates an FET driving signal having a logic voltage level when receiving a valve driving command from the ECU 13. If a preset initial driving time elapses from the driving of the valve 12, the controller 50 changes a PWM 15 duty value of the FET driving signal and transmits the PWM duty value to the second gate driver 42 such that the voltage applied to the valve 12 is lowered to a preset turn-on maintaining voltage. To this end, the controller 50 is provided therein with a voltage detector 51 to detect the driving voltage applied to 20 the valve 12 from the battery 10. The voltage detector 51 may be additionally provided outside the controller 50. The initial driving time refers to a time during which gas fuel is sufficiently supplied to the fuel supply line by 25 opening the valve 12. For example, the initial driving time may be set to about 10 seconds. In addition, the turn-on maintaining voltage refers to a voltage required to maintain the valve 12 at a turn-on state. According to an experimental value, the turn-on maintaining 5 voltage must have at least about 3V. According to the present embodiment, the turn-on maintaining voltage is set to about 4V. Therefore, according to the present invention, if the initial driving time elapses after the fuel cut solenoid valve is turned on by using a driving voltage, the PWM duty value of 10 the FET driving signal is changedto apply the turn-onmaintaifning voltage lower than the driving voltage to maintain the fuel cut solenoid valve at the turn-on state, so that the temperature of the fuel cut solenoid valve can be prevented from being raised. Hereinafter, a method for controlling a fuel pump motor 15 will be described according to an exemplary embodiment of the present invention. FIG. 3 is a flowchart showing the method for controlling the fuel pump motor according to the exemplary embodiment of the present invention. 20 As shown in FIG. 3, according to the method for controlling the motor of the exemplary embodiment of the present invention, the control of the motor is commenced by receiving the supply voltage from the power supply (not shown) if the input signal of an ignition key (IG, not shown) is applied in a state that 25 regular power is input from the battery 10 (slO).

As the input signal of the ignition key is input (s1O), the power converter 60 converts the supply voltage into a logic voltage of 5V and a driving voltage of 12V, and applies the driving voltage to the first gate driver 22, the motor driver 21, the 5 motor 11, the valve driver 41, and the valve 12 (sl). Then, the controller 50 receives a speed control signal and a valve driving signal, which are used to drive the motor 11 and the valve 12, from the ECU 13 to start the driving control of the motor 11 and the valve 12 (s12). 10 Hereinafter, a scheme of controlling the driving of the motor 11 will be described in brief. The controller 50 sets the duty value of a PWM control signal according to the target RPM based on the speed control signal and applies the duty value to the motor controller 23. The motor controller 23 generates 15 a 3-phase BLDC motor driving signal and applies the 3-phase BLDC motor driving signal to the gate terminal of the first FET device provided in the motor driver 21. According, if the first FET device is turned on so that the motor 11 is driven, the motor controller 23 transmits a tacho 20 signal according to the rotor position which is detected from the rotor position detector 31, to the controller 50. The controller 50 calculates the present RPM of the motor 11 based on the tacho signal, and changes the duty value the PWM control signal based the difference between the present RPM 25 and the target RPM based on the speed control signal, which is transmitted from the ECU 13, to continuously control the driving of the motor 11. Meanwhile, the overcurrent detector 32 detects the overcurrent applied to the motor 11 during the driving of the 5 motor 11. In this case, if the overcurrent is detected, the controller 50 restricts the driving of the motor 11. According to the present embodiment, the controller 50 controls the driving of the valve 12 while controlling the driving of the motor 11 through the above procedures. 10 Hereinafter, a scheme of controlling the driving of the valve 12 will be described in detail. The controller 50 generates the FET driving signal having the logic voltage level according to the valve driving signal received in step s12 and applies the FET driving signal to the second gate driver 42 (s13) . The 15 second gate driver 42 converts the FET driving signal into the voltage level of the driving voltage and applies the driving signal to the gate terminal of the second FET device. In this case, the FET driving signal has 100% of the PWM duty value. 20 Therefore, the second FET device is turned on (s14), so that the valve 12 is open (s15). Meanwhile, if the valve 12 is opened, the controller 50 computes time by using an internal timer. Accordingly, if the initial driving time, for example, 25 about 10 seconds elapses (s16), the controller 50 detects the voltage level of driving voltage by using the voltage detector 51 provided therein to determine the driving voltage applied to the valve 12 (s17). Then, the controller 50 sets the PWM duty value of the 5 FET driving signal such that the actually detected value of the driving voltage is maintained to the preset turn-on maintaining voltage (about 4V), and applies the FET driving signal having the PWM duty value to the second gate driver 42 (s18). For example, if the voltage detected in the voltage detector 10 51 is I2V that is j dentical to the drd ving voltage, the controller 50 sets the PWM duty value to about 33% that is a reference duty value, so that the voltage applied to the gate terminal of the second FET device is maintainedto the turn-on maintaining voltage of about 4V. 15 If the voltage detected in the voltage detector 51 is 10V which is a voltage lower than the driving voltage, the controller 50 sets the PWM duty value to about 40% which is a duty value higher than the reference duty. In contrast, if the voltage detected in the voltage detector 20 51 is 13V which is a voltage higher than the driving voltage, the controller 50 sets the PWM duty value to about 30% which is a duty value lower than the reference duty. As described above, the turn-on maintaining voltage is continuously applied to the gate terminal of the second FET device 25 by changing and setting the PWM duty value according to the variation of the driving voltage, so that the valve 12 is continuously maintained at an open state. According to the current consumption experiment of the present invention, if the initialdrivingtimeelapses, thevalve 5 is maintained at the open state by using the turn-on maintaining voltage, so that the current of about 300mA is consumed. Therefore, when comparing with an amount of consumed current of about 1A in the conventional valve driving scheme using a driving voltage, an amount of consumed current can be remarkably reduced. 1n Subsequently, the controller 50 performs step s17 to set the PWM duty value of the FET driving signal according to the driving voltage detected in the voltage detector 51 until the ignition key is turned off in step s19, thereby maintaining the valve 12 at an open state. 15 Iftheignitionkeyisturnedoffinsteps19, thecontroller 50 stops the driving of the motor 11 and the valve 12. Therefore, the driving of the motor 11 and the valve 12 is terminated (s20). According to the present invention, through the above 20 procedure, if the initial driving time elapses after the fuel cut solenoid valve is open, the turn-on maintaining voltage lower than the driving voltage is applied, so that the open state is continuously maintained. Accordingly, the temperature of the fuel cut solenoid valve can be prevented from being raised. 25 Although the exemplary embodiments of the present invention have been described, it is understood that the present invention should not be limited to these exemplary embodiments but various changes and modifications can be made by one ordinary skilled in the art within the spirit and scope of the present 5 invention as hereinafter claimed.

Claims

1. An apparatus for controlling a fuel pump motor to control driving of the fuel pump motor and driving of a fuel cut solenoid valve installed in a fuel supply line of supplying 5 fuel pumpedbya fuel pump to an engine, the apparatus comprising: a motor driving unit for driving the fuel pump motor; a detection unit for detecting a driving state of the fuel pump motor; a valve driving unit for driving the fuel cut solenoid 10 valve; a controller for controlling the driving of the motor driving unit and the valve driving unit based on a driving signal received from an ECU of a vehicle and a detecting result of the detection unit; and 15 a power converter for converting a supply voltage, which is supplied from a power supply of the vehicle, into a logic voltage, which is required to drive the controller and in the motor driving unit, and a driving voltage required to drive the motor and the fuel cut solenoid valve, 20 wherein the valve driving unit includes: a valve driver for driving the fuel cut solenoid valve by switching the driving voltage; and a gate driver for converting a level of an FET driving signal delivered from the controller into a voltage level of 25 the driving voltage of driving a motor driver to transmit the driving voltage to the valve driver.

2. The apparatus of claim 1, wherein the valve driver includes a first FET device, and the gate driver converts the 5 FET driving signal having a level of the logic voltage into a level of the driving voltage and applies the driving voltage to a gate terminal of the first FET device.

3. The apparatus of claim 1 or 2, further comprising a 10 voltage detector to detect the driving voltage, wherein the controller changes and sets a PWM duty value of the FET driving signal such that the driving voltage detected in the voltage detector is maintained to a preset turn-on maintaining voltage of the FET device if a preset initial driving 15 time elapses after the fuel cut solenoid valve is driven.

4. The apparatus of claim 3, wherein the motor driving unit includes a motor driver for driving the motor by switching the driving voltage; 20 a motor controller for generating a motor driving signal based on the duty value of the PWM control signal applied from the controller; and a second gate driver for converting and applying a voltage level of a motor driving signal into a level of the driving voltage, 25 and wherein the detection unit includes: a rotor position detector for detecting the position of a rotor by using a counter electromotive signal representing phases of the motor when the motor is driven; and 5 an overcurrent detector for detecting an overcurrrent applied to the motor to deliver the overcurrent to the controller.

5. A method for controlling a fuel pump motor, the method comprising: 10 converting a supply voltage into a logic vo-ltage requJ red to drive a motor driving unit and a driving voltage required to drive a fuel pump motor and a fuel cut solenoid valve; receiving a speed control signal and a valve driving signal used to control driving of the fuel pump motor and the fuel cut 15 solenoid valve from an ECU of a vehicle; controlling the driving of the fuel pump motor according to the speed control signal; and controlling the driving of the fuel cut solenoid valve based on the valve driving signal while controlling the driving 20 of the fuel pump motor, wherein the controlling the driving of the fuel cut solenoid valve based on the valve driving signal while controlling the driving of the fuel pump motor includes: generating an FET driving signal having the value of the 25 logic voltage according to the valve driving signal; converting the FET driving signal into a voltage level of the driving voltage to apply the FET driving signal to a gate terminal of an FET device; and opening the fuel cut solenoidvalve basedon the FET driving 5 signal that has been applied to the gate terminal of the FET device.

6. The method of claim 5, wherein the FET driving signal is set to 100% of a PWM duty value. 10

7. The method of claim 5, wherein the controlling the driving of the fuel cut solenoid valve based on the valve driving signal while controlling the driving of the fuel pump motor includes maintaining the driving voltage to a preset turn-on 15 maintaining voltage of the FET device if a preset initial driving time elapses after the fuel cut solenoid valve is driven.

8. The method of claim 7, wherein, in the maintaining the driving voltage to the preset turn-on maintaining voltage 20 of the FET device if the preset initial driving time elapses after the fuel cut solenoid valve is driven, a PWM duty value of the FET driving signal is set to a value higher than a preset reference duty value if a level of the driving voltage detected by a voltage detector is lower than the turn-on maintaining 25 voltage, and the PWM duty value of the FET driving signal is set to a value lower than the preset reference duty value if the level of the driving voltage is higher than the turn-on maintaining voltage. 5

9. The method of one of claims 5 to 8, wherein the controlling the driving of the fuel pump motor according to the speed control signal includes: setting a duty value of a PWM control signal according to a target RPM based on the speed control signal and driving 10 the fuel pump motor based on the duty value; detecting a position of a rotor by using counter electromotive signals represented in phases of the fuel pump motor when the motor is driven; calculating a present RPM of the motor by using the position 15 of the rotor; and changing the duty value of the PWM control signal according to a difference between the present RPM and the target RPM based on the speed control signal to control the driving of the fuel pump motor; and 20 restricting the driving of the fuel pump motor if an overcurrent is applied to the fuel pump motor during the driving of the fuel pump motor.

10. An apparatus and a method as substantially described 25 herein and as illustrated by the accompanying drawings.