Heater control apparatus for diesel fuel filter and driving method thereof

Abstract

A heater control apparatus for a diesel fuel filter according to an exemplary embodiment of the present disclosure includes a fuel temperature sensor for sensing a temperature of diesel fuel, a main relay including a first internal coil and a first switch, a pre-filter heater relay including a second internal coil and a second switch; a first node, a second node, a third node, and an engine control unit (ECU).

Claims

1. A heater control apparatus for a diesel fuel filter, comprising: a fuel temperature sensor for sensing a temperature of diesel fuel; a main relay including a first internal coil and a first switch; a pre-filter heater relay including a second internal coil and a second switch; a first node to which a positive terminal of a battery, one end of the first internal coil, one end of the first switch, and one end of the second switch are connected; a second node to which the other end of the first switch and one end of the second internal coil are connected; a third node to which the other end of the second switch, an anode of a first diode, and a pre-filter heater are connected; and an engine control unit (ECU) including a first switching element connected to the other end of the first internal coil, a second switching element connected to the other end of the second internal coil, and a first monitoring terminal connected to a cathode of the first diode, wherein when an ignition switch is turned on, the ECU turns on the first switching element, turns on or off the second switching element on the basis of the temperature of the diesel fuel, and determines whether the pre-filter heater relay has an error by checking a current flowing in the first diode through the first monitoring terminal.

2. The heater control apparatus of claim 1, wherein: when predetermined current flows in the first diode while the second switching element is in an OFF state, the ECU determines that the pre-filter heater relay is stuck closed.

3. The heater control apparatus of claim 1, wherein: when predetermined current does not flow in the first diode while the second switching element is in an ON state, the ECU determines that the pre-filter heater relay is stuck open.

4. The heater control apparatus of claim 1, further comprising: a main filter heater relay including a third internal coil connected to the second node at one end thereof and a third switch connected to the first node at one end thereof; and a fourth node to which the other end of the third switch, an anode of a second diode, and a main filter heater are connected, wherein the ECU further includes a third switching element connected to the other end of the third internal coil and a second monitoring terminal connected to a cathode of the second diode.

5. The heater control apparatus of claim 4, wherein the ECU turns on or turns off the third switching element on the basis of the temperature of the diesel fuel, and determines whether the main filter heater relay has an error by checking a current flowing in the second diode through the second monitoring terminal.

6. The heater control apparatus of claim 5, wherein when predetermined current flows in the second diode while the third switching element is in an OFF state, the ECU determines that the main filter heater relay is stuck closed.

7. The heater control apparatus of claim 5, wherein, when predetermined current does not flow in the second diode while the third switching element is in an ON state, the ECU determines that the main filter heater relay is stuck open.

8. A method for driving a heater control apparatus for a diesel fuel filter including a fuel temperature sensor for sensing a temperature of diesel fuel; a main relay including a first internal coil and a first switch; a pre-filter heater relay including a second internal coil and a second switch; a first node to which a positive terminal of a battery, one end of the first internal coil, one end of the first switch, and one end of the second switch are connected; a second node to which the other end of the first switch and one end of the second internal coil are connected; a third node to which the other end of the second switch, an anode of a first diode, and a pre-filter heater are connected; and an engine control unit (ECU) including a first switching element connected to the other end of the first internal coil, a second switching element connected to the other end of the second internal coil, and a first monitoring terminal connected to a cathode of the first diode, the method comprising: when an ignition switch is turned on, turning on the first switching element; turning on or turning off the second switching element on the basis of the temperature of the diesel fuel; and determining whether the pre-filter heater relay has an error by checking a current flowing in the first diode through the first monitoring terminal.

9. The method of claim 8, wherein the determining of whether the pre-filter heater relay has an error includes: when predetermined current flows in the first diode while the second switching element is in an OFF state, determining that the pre-filter heater is stuck closed.

10. The method of claim 8, wherein the determining of whether the pre-filter heater relay has an error includes: when predetermined current does not flow in the first diode while the second switching element is in an ON state, determining that the pre-filter heater is stuck open.

11. A method for driving a heater control apparatus for a diesel fuel filter including a fuel temperature sensor for sensing a temperature of diesel fuel; a main relay including a first internal coil and a first switch; a pre-filter heater relay including a second internal coil and a second switch; a main filter heater relay including a third internal coil and a third switch; a first node to which a positive terminal of a battery, one end of the first internal coil, one end of the first switch, one end of the second switch, and one end of the third switch are connected; a second node to which the other end of the first switch, one end of the second internal coil, and one end of the third internal coil are connected; a third node to which the other end of the second switch, an anode of a first diode, and a pre-filter heater are connected; a fourth node to which the other end of the third switch, an anode of a second diode, and a main filter heater are connected; and an engine control unit (ECU) including a first switching element connected to the other end of the first internal coil, a second switching element connected to the other end of the second internal coil, a third switching element connected to the other end of the third internal coil, a first monitoring terminal connected to a cathode of the first diode, and a second monitoring terminal connected to a cathode of the second diode, the method comprising: when an ignition switch is turned on, turning on the first switching element; turning on or turning off the second switching element on the basis of the temperature of the diesel fuel; and determining whether the main filter heater relay has an error by checking a current flowing in the second diode through the second monitoring terminal.

12. The method of claim 11, wherein the determining of whether the main filter heater relay has an error includes: when predetermined current flows in the second diode while the third switching element is in an OFF state, determining that the main filter heater relay is stuck closed.

13. The method of claim 11, wherein the determining of whether the main filter heater relay has an error includes: when predetermined current does not flow in the second diode while the third switching element is in an ON state, determining that the main filter heater relay is stuck open.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic view illustrating a configuration of a heater control apparatus for a diesel fuel filter according to an exemplary embodiment of the present disclosure.

(2) FIGS. 2 and 3 are flow charts illustrating a method for driving a heater control apparatus for a diesel fuel filter according to an exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION

(3) Hereinafter, the present disclosure will be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the disclosure are shown.

(4) In the drawings, the components are arbitrarily shown for the description purposes, so the present disclosure is not limited to the illustrations of the drawings.

(5) FIG. 1 is a view illustrating a configuration of a heater control apparatus for a diesel fuel filter according to an exemplary embodiment of the present disclosure.

(6) As illustrated in FIG. 1, a heater control apparatus for a diesel fuel filter according to an exemplary embodiment of the present disclosure may include a fuel temperature sensor 50, a main relay 11, a pre-filter heater relay 13, a main filter heater relay 15, and an engine control unit (ECU) 100.

(7) The fuel temperature sensor 50 senses a temperature of diesel fuel and transfers a corresponding signal to the ECU 100.

(8) When an ignition switch 40 is turned on, the ECU 100 drives the heater control apparatus for a diesel fuel filter according to an exemplary embodiment of the present disclosure.

(9) The ECU 100 may be implemented with one or more microprocessors executed by a preset program, and the preset program may include a series of commands for performing each step included in a method for driving a heater control apparatus for a diesel fuel filter according to an exemplary embodiment of the present disclosure described hereinafter.

(10) The ECU 100 may include a first switching element 110a, a second switching element 110b, and a third switching element 110c. The first switching element 110a, the second switching element 110b, and the third switching element 110c may be a MOSFET, but the present disclosure is not limited thereto.

(11) The main relay 11 may supply power of a battery to various power loads using power from the battery, or may cut off power supply thereto.

(12) The main relay 11 may include a first internal coil 11a, a first switch 11b, and a first freewheeling diode 11c.

(13) When the ignition switch 40 is turned on, the ECU 100 turns on the main relay 11. When the ignition switch 40 is turned on, the ECU 100 turns on the first switching element 110a. Accordingly, current flows in the first internal coil 11a and the first switch 11b is turned on to supply battery power to various power loads using the power of the battery. To this end, a positive terminal 5 of the battery, one end of the first internal coil 11a, and one end of the first switch 11b are connected to a first node N1. In order to remove a counter electromotive voltage generated in the first internal coil 11a, the first freewheeling diode 11c may be connected to the first internal coil 11a in parallel.

(14) The diesel fuel filter may include a pre-filter and a main filter in order to filter out impurities included in diesel fuel and separate moisture therefrom and discharge the separated moisture to the outside. The pre-filter primarily filters out relatively large impurities and the main filter secondarily filters out relatively small impurities remaining after primary screening of the pre-filter.

(15) The pre-filter heater 31 may be configured as a positive temperature coefficient (PTC) device capable of heating diesel fuel introduced to the pre-filter.

(16) In order to supply power to the pre-filter heater 31 or cut off power supply to the pre-filter heater 31, the pre-filter heater relay 13 is disposed at one end of the pre-filter heater 31.

(17) The pre-filter heater relay 13 may include a second internal coil 13a, a second switch 13b, and a second freewheeling diode 13c. The ECU 100 turns on or turns off the pre-filter heater relay 13 on the basis of a temperature of diesel fuel sensed by the fuel temperature sensor 50. When a temperature of the diesel fuel is lower than a preset temperature, the ECU 100 turns on the second switching element 110b. Accordingly, current flows in the second internal coil 13a, the second switch 13b is turned on, and power of the battery is supplied to the pre-filter heater 31. To this end, one end of the second switch 13b is connected to the first node N1 and the other end of the second switch 13b is connected to the pre-filter heater 31. Also, the other end of the first switch 11b and one end of the second internal coil 13a are connected to the second node N2. In order to remove a counter electromotive voltage generated in the second internal coil 13a, the second freewheeling diode 13c may be connected to the second internal coil 13b in parallel.

(18) In order to determine whether the pre-filter heater relay 13 has an error, the ECU 100 may further include a first monitoring terminal 120a connected to an anode of a first diode 21. The other end of the second switch 13b, a cathode of the first diode 21, and the pre-filter heater 31 are connected to a third node N3. The ECU 100 may determine whether the pre-filter heater relay 13 has an error by checking a current flowing in the first diode 21 through the first monitoring terminal 120a.

(19) The ECU 100 may determine whether the pre-filter heater relay 13 is stuck closed while the pre-filter heater 31 is not being driven. For example, when a temperature of diesel fuel is higher than the preset temperature, the second switching element 110b is maintained in an OFF state. Here, when the pre-filter heater relay 13 is normal, the second switch 13b is to be maintained in an OFF state and a current will not flow in the first diode 21. However, when predetermined current flows in the first diode 21 while the second switching element 110b is in the OFF state, the ECU 100 may determine that the pre-filter heater relay 13 is stuck closed.

(20) Also, the ECU 100 may determine whether the pre-filter heater relay 13 is stuck open while the pre-filter heater 31 is being driven. For example, when a temperature of diesel fuel is lower than the preset temperature, the second switching element 110b is maintained in an ON state. Here, when the pre-filter heater relay 13 is normal, the second switch 13b is to be maintained in an ON state and current will flow in the first diode 21. However, when predetermined current does not flow in the first diode 21 while the second switching element 110b is in the ON state, the ECU 100 may determine that the pre-filter heater relay 13 is stuck open.

(21) When it is determined that the pre-filter heater relay 13 is stuck closed or open, the ECU 100 may turn on a check lamp 60 to allow a corresponding driver to move a corresponding vehicle to a repair shop.

(22) The main filter heater 33 may also be configured as a positive temperature coefficient (PTC) device capable of heating diesel fuel introduced to the main filter.

(23) In order to supply power to the main filter heater 33 or cut off the power supply thereto, the main filter heater relay 15 is disposed at one end of the main filter heater 33.

(24) The main filter heater relay 15 may include a third internal coil 15a, a third switch 15b, and a third freewheeling diode 15c. The ECU 100 turns on or turns off the main filter heater relay 15 on the basis of a temperature of diesel fuel sensed by the fuel temperature sensor 50. When a temperature of the diesel fuel is lower than a preset temperature, the ECU 100 turns on the third switching element 110c. Accordingly, current flows in the third internal coil 15a, the third switch 15b is turned on, and power of the battery is supplied to the main filter heater 33. To this end, one end of the third switch 15b is connected to the first node N1 and the other end of the third switch 15b is connected to the main filter heater 33. Also, one end of the third internal coil 15a is connected to the second node N2. In order to remove a counter electromotive voltage generated in the third internal coil 15a, the third freewheeling diode 15c may be connected to the third internal coil 15a in parallel.

(25) In order to determine whether the main filter heater relay 15 has an error, the ECU 100 may further include a second monitoring terminal 120b connected to an anode of a second diode 23. The other end of the third switch 15b, a cathode of the second diode 23, and the main filter heater 33 are connected to a fourth node N4. The ECU 100 may determine whether the main filter heater relay 15 has an error by checking a current flowing in the second diode 23 through the second monitoring terminal 120b.

(26) The ECU 100 may determine whether the main filter heater relay 15 is stuck closed while the main filter heater 33 is not being driven. For example, when a temperature of diesel fuel is higher than the preset temperature, the third switching element 110c is maintained in an OFF state. Here, when the main filter heater relay 15 is normal, the third switch 15b is to be maintained in an OFF state and a current is not to flow in the second diode 23. However, when predetermined current flows in the second diode 23 while the third switching element 110c is in the OFF state, the ECU 100 may determine that the main filter heater relay 15 is stuck closed.

(27) Also, the ECU 100 may determine whether the main filter heater relay 15 is stuck open while the main filter heater 33 is being driven. For example, when a temperature of the diesel fuel is lower than the preset temperature, the third switching element 110c is maintained in an ON state. Here, when the main filter heater relay 15 is normal, the third switch 15b is to be maintained in an ON state and current is to flow in the second diode 23. However, when predetermined current does not flow in the second diode 23 while the third switching element 110c is in the ON state, the ECU 100 may determine that the main filter heater relay 15 is stuck open.

(28) When it is determined that the main filter heater relay 15 is stuck closed or open, the ECU 100 may turn on the check lamp 60 to allow the driver to move the vehicle to a repair shop.

(29) FIGS. 2 and 3 are flow charts illustrating a method for driving a heater control apparatus for a diesel fuel filter according to an exemplary embodiment of the present disclosure.

(30) Referring to FIG. 2, the ECU 100 may determine whether the pre-filter heater relay 13 has an error by checking a current flowing in the first diode 21 through the first monitoring terminal 120a.

(31) The ECU 100 determines whether the ignition switch 40 is in a turned-on state (S100).

(32) When the ignition switch is in the turned-on state, the ECU 100 turns on the first switching element 110a (S110). Thereafter, the ECU 100 drives the pre-filter heater 31 or stops driving of the pre-filter heater 31 by turning on or off the second switching element 110b on the basis of a temperature of diesel fuel.

(33) The ECU 100 determines whether the second switching element 110b is in an ON state (S120).

(34) When the second switching element 110b is in the ON state, the ECU 100 determines whether predetermined current flows in the first diode 21 (S130).

(35) When the predetermined current flows in the first diode 21 while the second switching element 110b is in the ON state, the ECU 100 may determine that the pre-filter heater relay 13 is in a normal state (S140).

(36) In contrast, when the predetermined current does not flow in the first diode 21 while the second switching element 110b is in the ON state, the ECU 100 may determine that the pre-filter heater relay 13 is stuck open (S150). In this case, the ECU 100 may turn on the check lamp 60 to allow the driver to move the vehicle to a repair shop (S160).

(37) Meanwhile, when the second switching element 110b is in an OFF state in step S120, the ECU 100 may determine whether the predetermined current flows in the first diode 21 (S170).

(38) When the predetermined current flows in the first diode 21 while the second switching element 110b is in the OFF state, the ECU 100 may determine that the pre-filter heater relay 13 is stuck closed (S180). In this case, the ECU 100 may turn on the check lamp 60 to allow the driver to move the vehicle to a repair shop (S160).

(39) When the predetermined current does not flow in the first diode 21 while the second switching element 110b is in the OFF state, the ECU 100 may determine that the pre-filter heater relay 13 is in a normal state (S190).

(40) Referring to FIG. 3, the ECU 100 may determine whether the main filter heater relay 15 has an error by checking a current flowing in the second diode 23 through the second monitoring terminal 120b.

(41) The ECU 100 may determine whether the ignition switch 40 is in a turned-on state (S200).

(42) When the ignition switch 40 is in the turned-on state, the ECU 100 turns on the first switching element 110a (S210). Thereafter, the ECU 100 drives the main filter heater 33 or stops driving thereof by turning on or off the third switching element 110c on the basis of a temperature of diesel fuel.

(43) The ECU 100 determines whether the third switching element 110c is in an ON state (S220).

(44) When the third switching element 110c is in the ON state, the ECU 100 may determine whether predetermined current flows in the second diode 23 (S230).

(45) When the predetermined current flows in the second diode 23 while the third switching element 110c is in the ON state, the ECU 100 may determine that the main filter heater relay 15 is in a normal state (S240).

(46) In contrast, when the predetermined current does not flow in the second diode 23 while the third switching element 110c is in the ON state, the ECU 100 may determine that the main filter heater relay 15 is stuck open (S250). In this case, the ECU 100 may turn on the check lamp 60 to allow the driver to move the vehicle to a repair shop (S260).

(47) Meanwhile, when the third switching element 110c is in an OFF state in step S220, the ECU 100 determines whether predetermined current flows in the second diode 23 (S270).

(48) When the predetermined current flows in the second diode 23 while the third switching element 110c is in the OFF state, the ECU 100 may determine that the main filter heater relay 15 is stuck closed (S280). In this case, the ECU 100 may turn on the check lamp 60 to allow the driver to move the vehicle to a repair shop (S260).

(49) When the predetermined current does not flow in the second diode 23 while the third switching element 110c is in the OFF state, the ECU 100 may determine that the main filter heater relay 15 is in a normal state (S290).

(50) As described above, according to an exemplary embodiment of the present disclosure, a fault of the filter heater relay may be determined in real time. Thus, damage to the diesel fuel filter according to the fault of the filter heater relay may be prevented. In addition, a degradation of a cold start of the diesel engine during cold weather may be prevented in advance.

(51) While this disclosure has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.