Solenoid valve diagnosis apparatus and method

Abstract

This invention relates to a solenoid valve diagnostic device and method. A solenoid valve diagnostic device includes: a plurality of solenoid valves that open or close the inlet / outlet of a fuel tank; a current sensor for measuring the operating current of the solenoid valves; and a controller for diagnosing whether the solenoid valves have failed based on the operating current measured by the current sensor. According to the invention, the hardware and size of the controller can be optimized, and cost savings can be achieved.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2021-0001591, filed with the Korean Intellectual Property Office on January 6, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a solenoid valve diagnostic device and method for diagnosing solenoid valve failure in a hydrogen storage system used to drive a fuel cell system. Background Technology

[0004] Fuel cell vehicles operate using electricity generated through the electrochemical reaction of hydrogen and oxygen. A fuel cell vehicle includes a fuel cell that generates electricity and a fuel tank that stores hydrogen to be supplied to the fuel cell. The fuel tank is equipped with a solenoid valve. The solenoid valve controls the input and output of hydrogen from the fuel tank. When the supply of hydrogen fuel to the fuel cell is limited due to solenoid valve failure, the generated electricity decreases, and the vehicle becomes inoperable. In related fields, to diagnose solenoid valve failure, the controller monitors the current supplied to the solenoid valve using a current sensor and enters a failure diagnosis mode when the detected current is less than or equal to a predetermined current value. However, failure diagnosis methods in related fields cannot perform diagnosis via signal feedback when controlled by pulse width modulation (PWM) duty cycle (100%) or direct current (DC) type solenoid valves. Therefore, a diagnostic mode must be entered using a current sensor, and as many current sensors as valves must be installed to diagnose each solenoid valve. Due to this requirement, the controller size may increase, and production costs may become prohibitively high. Summary of the Invention

[0005] One aspect of the present invention provides a solenoid valve diagnostic apparatus and method for diagnosing failures of multiple solenoid valves by using a single current sensor.

[0006] The technical problems to be solved by the present invention are not limited to the foregoing problems, and any other technical problems not mentioned herein will be clearly understood by those skilled in the art through the following description.

[0007] According to one aspect of the invention, a solenoid valve diagnostic device includes: a plurality of solenoid valves for opening or closing the inlet / outlet of a fuel tank; a current sensor for measuring the operating current of the solenoid valves; and a controller for diagnosing whether the solenoid valves have failed based on the operating current measured by the current sensor.

[0008] The controller can determine whether the measured operating current meets the conditions for entering diagnostic mode.

[0009] The condition for entering diagnostic mode is that the measured operating current is less than the reference current set differently for the corresponding inspection step.

[0010] When the controller enters diagnostic mode, it can change the duty cycle of the PWM control signal sent to the solenoid valve. When the duty cycle of the PWM control signal is inverted from the duty cycle of the PWM control signal fed back from the solenoid valve, the controller can determine the normal condition of the solenoid valve.

[0011] When the solenoid valve is determined to be in normal condition in diagnostic mode, the controller can maintain the current inspection procedure.

[0012] If the duty cycle of the PWM control signal and the duty cycle of the feedback PWM control signal do not reverse, the controller can determine that the solenoid valve has failed.

[0013] When a solenoid valve failure is determined, the controller can proceed to the next inspection step.

[0014] According to another aspect of the present invention, a solenoid valve diagnostic method includes the following steps: measuring the operating current of a plurality of solenoid valves by means of a current sensor; and diagnosing whether the solenoid valves have failed by means of a controller based on the measured operating current.

[0015] Diagnosing whether a solenoid valve is malfunctioning may include: determining whether the measured operating current meets the conditions for entering the diagnostic mode; entering the diagnostic mode when the measured operating current meets the conditions; and determining the solenoid valve malfunction by using a PWM feedback measurement method in the diagnostic mode.

[0016] Determining whether the measured operating current meets the conditions for entering diagnostic mode may include determining whether the measured operating current is less than the reference current set differently for the corresponding operating steps.

[0017] Determining a solenoid valve failure may include: changing the duty cycle of the PWM control signal transmitted to the solenoid valve; identifying the duty cycle of the PWM control signal fed back from the solenoid valve; determining the solenoid valve to be in normal condition when the duty cycle of the PWM control signal and the duty cycle of the fed-back PWM control signal are reversed; and determining the solenoid valve to be in failure when the duty cycle of the PWM control signal and the duty cycle of the fed-back PWM control signal are reversed.

[0018] Diagnosing whether a solenoid valve is malfunctioning may include: when it is determined that the solenoid valve is malfunctioning, proceeding to the next inspection step.

[0019] Diagnosing whether a solenoid valve is malfunctioning may also include: if the solenoid valve is determined to be in a normal condition, maintaining the current inspection procedure. Attached Figure Description

[0020] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings:

[0021] Figure 1 This is a view illustrating the configuration of a solenoid valve diagnostic device according to an embodiment of the present invention; and

[0022] Figure 2A and Figure 2B This is a flowchart illustrating a solenoid valve diagnostic method according to an embodiment of the present invention. Detailed Implementation

[0023] It should be understood that, as used herein, the term "vehicle" or "of a vehicle" or other similar terms include motor vehicles in the general sense, such as: passenger cars, including sport utility vehicles (SUVs), buses, trucks; various commercial vehicles; boats, including various boats and vessels; aircraft, etc., and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., vehicles derived from fuels other than petroleum). As described herein, a hybrid vehicle is a vehicle having two or more power sources, including both gasoline and electric power.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. As used herein, the singular forms “a” and “described” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term “comprising” as used in this specification indicates the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Throughout this specification, unless expressly stated otherwise, the word “comprising” and its variations shall be understood to imply the inclusion of stated elements but not the exclusion of any other elements. Furthermore, the terms “unit,” “device,” “machine,” and “module” described in this specification mean a unit for performing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

[0025] Furthermore, the control logic of the present invention can be implemented as a non-transitory computer-readable medium containing executable program instructions that are executed by a processor, controller, or the like. Examples of computer-readable media include, but are not limited to, ROM, RAM, optical disc (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage device. The computer-readable medium can also be distributed across a network-coupled computer system, enabling distributed storage and execution, for example, via a telematics server or a controller area network (CAN).

[0026] Hereinafter, some embodiments of the invention will be described in detail with reference to the exemplary accompanying drawings. When adding reference numerals to components in each drawing, it should be noted that identical or equivalent components are referred to by the same reference numerals even when they are shown in other drawings. Furthermore, in describing embodiments of the invention, detailed descriptions of well-known features or functions will be omitted so as not to unnecessarily obscure the essence of the invention.

[0027] In describing components according to embodiments of the invention, terms such as first, second, "A", "B", (a), (b), etc., may be used. These terms are merely intended to distinguish one component from another, and they do not limit the nature, order, or sequence of the components. Unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as those commonly understood by one of ordinary skill in the art to which this invention pertains. Such terms, as defined in common dictionaries, should be interpreted as having the same meaning as their contextual meaning in the relevant technical field and should not be interpreted as having an ideal or overly formal meaning unless clearly defined as having such meaning in this application.

[0028] Embodiments of the present invention relate to techniques for diagnosing whether a solenoid valve in a hydrogen storage system used to drive a fuel cell system has failed.

[0029] Figure 1 This is a view showing the configuration of a solenoid valve diagnostic device 100 according to an embodiment of the present invention.

[0030] refer to Figure 1 The solenoid valve diagnostic device 100 may include a fuel tank 110, a fuel cell stack 120, multiple valves 130 (preferably solenoid valves), a current sensor 140, and a controller 150.

[0031] Fuel tank 110 is a fuel supply device for storing hydrogen to be supplied to fuel cell stack 120. Fuel tank (or multiple fuel tanks) 110 may be installed in a vehicle. In these embodiments, fuel tank 110 is exemplified as three fuel tanks 111, 112, and 113 installed in a vehicle. However, the invention is not limited thereto. For example, two, four, or more fuel tanks 110 may be installed in a vehicle.

[0032] The fuel cell stack 120 generates electrical energy through the electrochemical reaction of hydrogen and oxygen. The fuel cell stack 120 can receive hydrogen from the fuel tank 110 and generate electricity. The electrical energy generated by the fuel cell stack 120 can be used to drive an electric motor (not shown).

[0033] Valve 130 can open or close the hydrogen fuel supply channel from fuel tank 110 to fuel cell stack 120. Valve 130 can be opened or closed depending on a control signal input from controller 150 to supply hydrogen stored in fuel tank 110 to fuel cell stack 120 or to interrupt the hydrogen supply to fuel cell stack 120. Valve 130 can be installed outside or inside fuel tank 110. Valve 130 may include a first solenoid valve V1, a second solenoid valve V2, and a third solenoid valve V3 respectively installed outside or inside the first fuel tank 111, the second fuel tank 112, and the third fuel tank 113. The number of valves 130 can increase with the number of fuel tanks 110.

[0034] Current sensor 140 can measure the operating current (drive current) of valve 130. Current sensor 140 can measure the total current supplied to the first solenoid valve V1, the second solenoid valve V2, and the third solenoid valve V3. In this embodiment, current sensor 140 is described as being located outside the controller 150. However, this is not a limitation, and current sensor 140 can be configured to be located within the controller 150.

[0035] The controller 150 may be electrically connected to the valve 130 and the current sensor 140. The controller 150 may include a processor. This processor can control the overall operation of the controller 150 and may be a central processing unit (CPU), a microcontroller, and / or a microprocessor. The controller 150 may also include memory located within and / or outside the controller 150. The memory may be a non-transitory storage medium that stores instructions executed by the processor. The memory may be flash memory, a hard disk drive, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), electrically erasable programmable ROM (EEPROM), erasable programmable ROM (EPROM), and / or registers.

[0036] The controller 150 can control the opening / closing of the valve 130 using pulse width modulation (PWM) control. The controller 150 can adjust the duty cycle of the PWM control signal supplied to the valve 130.

[0037] The controller 150 can detect the operating current of the valve 130 using the current sensor 140. The controller 150 can determine whether to enter a diagnostic mode for diagnosing solenoid valve failure based on the detected operating current. The controller 150 can determine whether to proceed to an inspection step based on the diagnostic results in the diagnostic mode. The controller 150 can maintain the current inspection step when the solenoid valve is diagnosed as normal, and can proceed to the next inspection step when the solenoid valve is diagnosed as faulty. The number of inspection steps can be determined based on the number of solenoid valves and the conditions for entering the diagnostic mode; that is, different settings can be made for the reference current for the corresponding inspection steps. For example, when the number of solenoid valves is N, the inspection steps can be divided into: a first inspection step checking the state of the solenoid valves when N solenoid valves are normal, a second inspection step checking the state of the solenoid valves when N-1 solenoid valves are normal, ..., and an Nth inspection step checking the state of the solenoid valves when one solenoid valve is normal.

[0038] When the operating current detected during the corresponding inspection steps meets the conditions for entering the diagnostic mode, the controller 150 can enter the diagnostic mode and diagnose the valve 130. At this time, the controller 150 can determine whether the solenoid valve is malfunctioning by using a PWM feedback measurement method. When entering the diagnostic mode, the controller 150 can change the PWM duty cycle of the control signal transmitted to the valve 130. For example, the controller 150 can change the duty cycle of the PWM control signal from 100% to 90%. The controller 150 can transmit the PWM control signal with the changed duty cycle to the valve 130 and can receive the PWM control signal fed back from the valve 130 (i.e., the PWM feedback signal). The controller 150 can identify the duty cycle of the PWM feedback signal and can determine whether the solenoid valve is malfunctioning based on the identified duty cycle. The controller 150 can determine whether the duty cycle of the PWM control signal and the duty cycle of the PWM feedback signal are reversed. When it is determined that the duty cycle of the PWM control signal and the duty cycle of the PWM feedback signal are reversed, the controller 150 can determine that the solenoid valve is in normal condition. When it is determined that the duty cycle of the PWM control signal and the duty cycle of the PWM feedback signal have not reversed, the controller 150 can determine that the solenoid valve has failed.

[0039] The following description uses the failure of three solenoid valves, V1, V2 and V3, as an example to illustrate the process.

[0040] When the three solenoid valves V1, V2, and V3 are functioning normally, the controller 150 can operate in the first inspection step. In this first inspection step, the controller 150 can detect (measure) the operating current of solenoid valves V1, V2, and V3 using current sensor 140. The controller 150 can determine that the detected operating current is greater than or equal to a first reference current (e.g., 2.1A). When the detected operating current is greater than or equal to the first reference current, the controller 150 can determine that the solenoid valves are functioning normally. That is, the controller 150 can determine that all solenoid valves V1, V2, and V3 are functioning normally.

[0041] When the detected operating current is less than the first reference current, the controller can enter the first diagnostic mode. In the first diagnostic mode, the controller 150 can change the PWM duty cycle to 90% and send a PWM control signal with the changed duty cycle to solenoid valves V1, V2, and V3. The controller 150 can receive the PWM feedback signal, identify the duty cycle of the received PWM feedback signal, and determine whether the solenoid valve is malfunctioning. When the duty cycle of the received PWM feedback signal is equal to 10%, the controller 150 can determine that the solenoid valve is functioning normally. When the duty cycle of the received PWM feedback signal is not equal to 10%, the controller 150 can determine that the solenoid valve is malfunctioning.

[0042] When the solenoid valves are determined to be in normal condition in the first diagnostic mode, the controller 150 can determine that all solenoid valves V1, V2, and V3 are normal. When the solenoid valves are determined to be malfunctioning in the first diagnostic mode, the controller 150 can proceed to the next inspection step, namely the second inspection step.

[0043] In the second inspection step, the controller 150 can detect the operating current of solenoid valves V1, V2, and V3 using current sensor 140, and determine whether the operating current is greater than or equal to a second reference current (e.g., 1.4A). When the detected operating current is greater than or equal to the second reference current, the controller 150 can determine that the two solenoid valves are functioning normally.

[0044] When the detected operating current is less than the second reference current, the controller can enter the second diagnostic mode. Similar to the first diagnostic mode, when entering the second diagnostic mode, the controller 150 can diagnose solenoid valve failure using a PWM feedback measurement method. When the solenoid valve is diagnosed as normal in the second diagnostic mode, the controller 150 can determine that both solenoid valves are functioning correctly. When a solenoid valve failure is diagnosed in the second diagnostic mode, the controller 150 can proceed to the next inspection step, namely the third inspection step.

[0045] In the third inspection step, controller 150 can measure the operating current of solenoid valves V1, V2, and V3 using current sensor 140. Controller 150 can determine whether the measured operating current is greater than or equal to a third reference current (e.g., 0.7A). When the measured operating current is greater than or equal to the third reference current, controller 150 can determine that one solenoid valve is functioning correctly. When the measured operating current is less than the third reference current, controller 150 can enter a third diagnostic mode. Even in the third diagnostic mode, controller 150 can diagnose solenoid valve failure using a PWM feedback measurement method. When diagnosing normal solenoid valve condition in the third diagnostic mode, controller 150 can determine that one solenoid valve is functioning correctly. When diagnosing solenoid valve failure, controller 150 can determine that all solenoid valves have failed.

[0046] Figure 2A and Figure 2B A flowchart illustrating a solenoid valve diagnostic method according to an embodiment of the present invention is provided. In this embodiment, for better understanding, a case of diagnosing a failure in three solenoid valves V1, V2, and V3 is described as an example. However, the invention is not limited thereto.

[0047] The controller 150 can measure the operating current of multiple solenoid valves V1, V2, and V3 using the current sensor 140 (S100). The controller 150 can measure the total current supplied to the solenoid valves V1, V2, and V3.

[0048] The controller 150 can determine whether the measured operating current is less than the first reference current (S110). The controller 150 can determine whether the measured operating current is less than the first reference current, for example, 2.1A.

[0049] When the measured operating current is not less than the first reference current, the controller 150 can determine that all solenoid valves are normal (S120). When the measured operating current is greater than or equal to the first reference current, the controller 150 can determine that solenoid valves V1, V2, and V3 are normal.

[0050] When the measured operating current is less than the first reference current, the controller 150 can enter the first diagnostic mode (S130). The controller 150 can change the duty cycle of the PWM control signal when entering the first diagnostic mode. For example, the controller 150 can change the duty cycle of the PWM control signal from 100% to 90%.

[0051] In the first diagnostic mode, controller 150 can determine whether the solenoid valves are malfunctioning (S140). Controller 150 can transmit a PWM control signal with a changed duty cycle to solenoid valves V1, V2, and V3. Controller 150 can receive PWM feedback signals and identify the duty cycle of the received PWM feedback signals. When the identified duty cycle of the PWM feedback signal is inverted compared to the actual duty cycle of the PWM feedback signal, i.e., when the identified duty cycle of the PWM feedback signal is equal to 10%, controller 150 can determine that the solenoid valves are functioning normally. When the identified duty cycle of the PWM feedback signal is not equal to 10%, controller 150 can determine that the solenoid valves are malfunctioning.

[0052] When the solenoid valve is determined to be in normal condition in the first diagnostic mode, the controller 150 can determine that all solenoid valves are normal (S120).

[0053] When a solenoid valve failure is determined in the first diagnostic mode, the controller 150 can proceed to the next inspection step and can measure the operating current of multiple solenoid valves V1, V2 and V3 by using a current sensor (S150).

[0054] The controller 150 can determine whether the measured operating current is less than the second reference current (S160). For example, the controller 150 can determine whether the measured operating current is less than 1.4A.

[0055] When the measured operating current is not less than the second reference current, the controller 150 can determine that all but one of the multiple solenoid valves V1, V2, and V3 are normal (S170). When the measured operating current is greater than or equal to the second reference current, the controller 150 can determine that two of the three solenoid valves V1, V2, and V3 are normal.

[0056] When the measured operating current is less than the second reference current, the controller 150 can enter the second diagnostic mode (S180).

[0057] In the second diagnostic mode, the controller 150 can determine whether the solenoid valve has failed (S190). Similar to the first diagnostic mode, when entering the second diagnostic mode, the controller 150 can diagnose the solenoid valve failure by using a PWM feedback measurement method.

[0058] When the normal condition of the solenoid valves is determined in the second diagnostic mode, the controller 150 can determine that both solenoid valves are normal (S170).

[0059] When a solenoid valve failure is determined in the second diagnostic mode, the controller 150 can proceed to the next inspection step and can measure the operating current of multiple solenoid valves V1, V2 and V3 by using a current sensor (S200).

[0060] The controller 150 can determine whether the measured operating current is less than the third reference current (S210).

[0061] When the measured operating current is not less than the third reference current, the controller 150 can determine that one of the solenoid valves is normal (S220). When the measured operating current is greater than or equal to the third reference current, the controller 150 can determine that one of the three solenoid valves V1, V2 and V3 is normal.

[0062] When the measured operating current is less than the third reference current, the controller 150 can enter the third diagnostic mode (S230).

[0063] In the third diagnostic mode, the controller 150 can determine whether the solenoid valve has failed (S240). In the third diagnostic mode, the controller 150 can diagnose the solenoid valve failure by using a PWM feedback measurement method.

[0064] When the normal condition of the solenoid valve is determined in the third diagnostic mode, the controller 150 can determine that a solenoid valve is normal (S220).

[0065] When a solenoid valve failure is determined in the third diagnostic mode, the controller 150 can determine that all solenoid valves have failed (S250).

[0066] According to the present invention, the failure of multiple solenoid valves can be diagnosed using a single current sensor. This allows for optimization of the controller's hardware and size, and enables cost savings.

[0067] According to the present invention, even under PWM duty cycle of 100% or DC type solenoid valve control, the failure of the solenoid valve can be diagnosed through signal feedback.

[0068] Although the invention has been described above with reference to exemplary embodiments and accompanying drawings, the invention is not limited thereto, and various modifications and alterations can be made to the invention by those skilled in the art without departing from the spirit and scope of the invention as claimed in the following claims. Therefore, exemplary embodiments of the invention are provided to explain the spirit and scope of the invention, and not to limit them, and the spirit and scope of the invention are not limited by these embodiments. The scope of the invention should be interpreted based on the accompanying drawings, and the technical ideas within the scope of the claims should be included within the scope of the invention.

Claims

1. A solenoid valve diagnostic device, comprising: Multiple solenoid valves, each configured to open or close the inlet / outlet of the fuel tank; A current sensor configured to measure the operating current of the solenoid valve; as well as A controller configured to diagnose whether the solenoid valve has failed based on the operating current measured by the current sensor. The controller is configured as follows: Determine whether the measured operating current meets the conditions for entering diagnostic mode. When the controller enters diagnostic mode, it changes the duty cycle of the PWM control signal sent to the solenoid valve. as well as When the duty cycle of the PWM control signal reverses the duty cycle of the PWM control signal fed back from the solenoid valve, the solenoid valve is determined to be in normal condition.

2. The solenoid valve diagnostic device according to claim 1, wherein, The condition for entering diagnostic mode is that the measured operating current is less than the reference current set differently for the corresponding inspection steps.

3. The solenoid valve diagnostic device according to claim 1, wherein, When the solenoid valve is determined to be in normal condition in the diagnostic mode, the controller maintains the current inspection procedure.

4. The solenoid valve diagnostic device according to claim 1, wherein, The controller determines that the solenoid valve has failed when the duty cycle of the PWM control signal does not reverse with the duty cycle of the feedback PWM control signal.

5. The solenoid valve diagnostic device according to claim 4, wherein, When the solenoid valve is determined to be faulty, the controller proceeds to the next inspection step.

6. A method for diagnosing a solenoid valve, comprising the following steps: The operating current of multiple solenoid valves is measured using a current sensor. as well as The controller diagnoses whether the solenoid valve is malfunctioning based on the measured operating current. The diagnosis of whether the solenoid valve is malfunctioning includes: Determine whether the measured operating current meets the conditions for entering diagnostic mode; When the measured operating current meets the conditions for entering the diagnostic mode, the diagnostic mode is entered; and The failure of the solenoid valve is determined by using the PWM feedback measurement method in the diagnostic mode. The determination of the solenoid valve failure includes: Change the duty cycle of the PWM control signal transmitted to the solenoid valve; Identify the duty cycle of the PWM control signal fed back from the solenoid valve; When the duty cycle of the PWM control signal reverses the duty cycle of the feedback PWM control signal, the solenoid valve is confirmed to be in normal condition.

7. The solenoid valve diagnostic method according to claim 6, wherein, Determining whether the measured operating current meets the conditions for entering diagnostic mode includes: Determine whether the measured operating current is less than the reference current set for the corresponding inspection procedure.

8. The solenoid valve diagnostic method according to claim 6, wherein, Determining the failure of the solenoid valve also includes: If the duty cycle of the PWM control signal and the duty cycle of the feedback PWM control signal do not reverse, the solenoid valve is determined to be faulty.

9. The solenoid valve diagnostic method according to claim 8, wherein, Diagnosing whether the solenoid valve is malfunctioning includes: If the solenoid valve is determined to be faulty, proceed to the next inspection step.

10. The solenoid valve diagnostic method according to claim 8, wherein, Diagnosing whether the solenoid valve has failed also includes: If the solenoid valve is determined to be in normal condition, continue the current inspection procedure.

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