Device for fault diagnosis and method for fault diagnosis

Abstract

A fault diagnosis device comprising: an input section that receives a downstream pressure value, an upstream pressure value, and a most upstream pressure value in a fuel supply system, wherein the downstream pressure value is detected on a downstream side of a fuel pump that pressurizes and discharges fuel pumped up by a feed pump from a storage section in the fuel supply system, wherein the upstream pressure value is detected on an upstream side of the fuel pump, the most upstream pressure value is detected on an upstream side of a fuel filter and a downstream side of the feed pump, wherein the fuel filter is provided on an upstream side of the fuel pump, the fuel filter trapping foreign matter contained in the fuel; a determination section which, when the downstream pressure value is below a preset first threshold, determines whether the upstream pressure value is below a preset second threshold, and which, when the upstream pressure value is less than the preset second threshold, determines whether the most upstream pressure value is less than a preset third threshold, wherein the preset third threshold is determined depending on a rotational speed of an internal combustion engine, wherein the determining section determines that a malfunction has occurred on the upstream side of the fuel pump when the upstream pressure value is less than the second threshold value, the determination section determines that a malfunction has occurred in the fuel pump if the value of the pressure upstream of the pump is equal to or greater than the second threshold value, the determination section determines that a malfunction has occurred on an upstream side of the fuel filter when the most upstream pressure value is less than the third threshold value, the determination section determines that a malfunction has occurred in the fuel filter if the most upstream pressure value is equal to or greater than the third threshold value, and the determining section outputs information about the diagnosis result to a predetermined device indicating a location where the malfunction occurs.

Description

Technical area

[0001] The present disclosure relates to a fault diagnosis apparatus for diagnosing a malfunction of a fuel pump and a method for diagnosing a malfunction of the fuel supply system. State of the art

[0002] A conventional fuel supply system that supplies fuel stored in a fuel tank (e.g., a pressure accumulator) to the internal combustion engine side is known (see, for example, JP 2009 - 57 928 A). In the fuel supply system, for example, the fuel pumped from the fuel tank by a feed pump passes through a fuel filter, and after the flow rate is adjusted by a flow control valve, the fuel is pressurized and pumped to the internal combustion engine side by a high-pressure pump.

[0003] JP 2015 - 86 812 A relates to a control device for determining which of a fuel supply area and a fuel pressure area of ​​a common rail system has an abnormality.

[0004] DE 10 2004 029 454 A1 relates to a low-pressure side fuel pressure sensor that detects fuel pressure within a low-pressure side fuel pipe connecting a low-pressure pump to a high-pressure pump. An electronic control unit counts the number of times that the low-pressure side fuel pressure is lower than a normal range within a first predetermined period of time and determines that a first abnormal operation has been initiated if the counted value is equal to or greater than a predetermined value.

[0005] DE 10 2013 106 374 A1 relates to a fuel injection control unit. The fuel injection control unit samples and AD-converts a drive current of a feed pump at a specified time interval and filters the AD-converted values ​​with a bandpass filter. Summary of the inventionTechnical problem

[0006] Unfortunately, if a malfunction occurs in the fuel supply system described above, it is necessary to disassemble and examine the fuel supply system to determine the location of the malfunction.

[0007] It is an object to provide a malfunction diagnosis device and a malfunction diagnosis method capable of identifying the location of the malfunction without requiring disassembly. The subject of the present disclosure is to provide a malfunction diagnosis device and a malfunction diagnosis method capable of identifying the location of the malfunction without requiring disassembly. Solution to the problem

[0008] The above-mentioned object is achieved by the features of the independent patent claims. Advantageous developments of the invention are described in the subclaims.

[0009] A fault diagnosis apparatus according to one aspect of the present disclosure includes an input portion that receives a downstream pressure value and an upstream pressure value in a fuel supply system, the downstream pressure value being detected on a downstream side of a fuel pump that pressurizes and discharges fuel pumped up from a storage portion in the fuel supply system, the upstream pressure value being detected on an upstream side of the fuel pump;and a determination section that, when the downstream pressure value is less than a preset first threshold, determines whether the upstream pressure value is less than a preset second threshold, wherein the determination section determines that a malfunction has occurred on the upstream side of the fuel pump when the upstream pressure value is less than the second threshold, and the determination section determines that a malfunction has occurred at the fuel pump when the upstream pressure value is equal to or greater than the second threshold;

[0010] A method for diagnosing a malfunction according to one aspect of the present disclosure includes: receiving a downstream pressure value and an upstream pressure value in a fuel supply system, the downstream pressure value being detected on a downstream side of a fuel pump that pressurizes and discharges fuel pumped up from a storage portion in the fuel supply system, the upstream pressure value being detected on an upstream side of the fuel pump; determining whether the upstream pressure value is less than a preset second threshold if the downstream pressure value is less than a preset first threshold;and determining that a malfunction has occurred on the upstream side of the fuel pump when the upstream pressure value is less than the second threshold, and determining that a malfunction has occurred on the fuel pump when the upstream pressure value is equal to or greater than the second threshold; Beneficial effects of an invention

[0011] The present disclosure enables the location of a malfunction to be identified without requiring disassembly. Short description of the characters Fig. 1 shows an exemplary configuration of a fuel supply system and a fault diagnosis apparatus according to an embodiment of the present disclosure; and Fig. 2 illustrates an exemplary operation of the fault diagnosis apparatus according to the embodiment of the present disclosure. Description of the embodiments

[0012] In the following, embodiments of the present disclosure will be described in detail with reference to the figures.

[0013] A configuration of fuel supply system 1 and fault diagnosis apparatus 100 according to an embodiment of the present disclosure will be described with reference to Fig. 1 described.

[0014] Fig. 1 shows an exemplary configuration of fuel supply system 1 and fault diagnosis device 100. In Fig. 1, the solid arrows indicate the fuel flow and the dashed arrows indicate the flow of electrical signals.

[0015] The fuel supply system 1 and the Fig. The fault diagnosis device 100 shown in Figure 1 is mounted on a vehicle equipped with an internal combustion engine (e.g., a diesel engine) powered by fuel (e.g., light oil). The fuel supply system 1 serves to supply fuel to the internal combustion engine, and the fault diagnosis device 100 serves to identify the occurrence and location of a fault in the fuel supply system 1.

[0016] The configuration of the fuel supply system 1 is now described.

[0017] The fuel supply system 1 includes the fuel tank 2 for storing fuel (an example of a storage section), the feed pump 3 for pumping up the fuel from the fuel tank 2, the fuel filter 4 for collecting foreign substances contained in the fuel, and the fuel pump 5 for delivering the fuel to the accumulator 8.

[0018] The fuel pump 5 includes a flow control valve 6 for adjusting the flow rate of the fuel and a high pressure pump 7 for pressurizing the fuel until the fuel has a high pressure.

[0019] The opening of the flow control valve 6 is controlled by a control device (e.g., electric control unit or ECU) not shown so that the pressure (accumulator pressure) of the fuel stored in the accumulator 8 becomes a target accumulator pressure determined based on the operating state (e.g., the engine speed and the accelerator opening).

[0020] Common rail 8 is equipped with a first pressure sensor 9 for detecting the above-described accumulator pressure and outputting a value indicative of the detected accumulator pressure to the fault diagnosis device 100 when necessary. This pressure value is detected on the downstream side of the fuel pump 5 by the first pressure sensor 9 and is therefore hereinafter referred to as the "downstream pressure value."

[0021] A second pressure sensor 10 is provided on a side downstream of the fuel filter 4 and upstream of the fuel pump 5 to detect the fuel pressure on the side downstream of the fuel filter 4 and upstream of the fuel pump 5 and, if necessary, output a value indicating the detected pressure to the fault diagnosis device 100. This pressure value is detected on the upstream side of the fuel pump 5 by the second pressure sensor 10 and is therefore hereinafter referred to as the "upstream pressure value."

[0022] Fig. 1 illustrates a configuration with a feed pump 3 installed on the upstream side of the fuel filter 4, but the present embodiment is not limited to the configuration, and the feed pump 3 may be installed on the fuel pump 5, for example.

[0023] In the Fig. 1, a fuel filter other than fuel filter 4 can be installed on the upstream side of the fuel filter 4 (e.g. between fuel tank 2 and feed pump 3).

[0024] In the configuration of the fuel supply system 1 as set forth above, the fuel stored in the fuel tank 2 is pumped up by the feed pump 3, and after the foreign matter is captured by the fuel filter 4, the fuel flows into the fuel pump 5. The fuel, whose flow rate is adjusted by the flow control valve 6 based on the operating state of the internal combustion engine, is pressurized to high pressure by the high-pressure pump 7 and discharged to the accumulator 8. The fuel stored in the accumulator 8 is supplied to the injector (not shown) of the internal combustion engine.

[0025] The configuration of the fault diagnosis device 100 will now be described.

[0026] The fault diagnosis device 100 includes the input section 110 and the detection section 120.

[0027] Although not shown in the drawings, the fault diagnosis device 100 includes, for example, a central processing unit (CPU), a storage medium such as a read-only memory (ROM) that stores control programs, a working memory such as a random access memory (RAM), and a communication circuit. The function of the determination section 120 described below is realized by the CPU executing a computer program.

[0028] The input section 110 receives, if necessary, the downstream pressure value from the first pressure sensor 9. The input section 110 also receives, if necessary, the upstream pressure value from the second pressure sensor 10.

[0029] The determination section 120 determines whether the downstream pressure value is below a preset first threshold. The first threshold is, for example, a pressure value determined depending on the engine speed and the accelerator opening. An example of the first threshold is the target pressure accumulator described above. The first threshold is set based on the results of experiments, simulations, and the like conducted in advance.

[0030] The input section 110 may receive the first threshold value from another device (e.g., a control unit), or the determination section 120 may calculate the first threshold value. The calculation by the determination section 120 is, for example, as follows. The input section 110 receives a detected value from a crank angle sensor (not shown) and a detected value from an accelerator opening sensor (not shown). The determination section 120 then calculates the engine speed based on the detected crank angle. The determination section 120 then identifies a target accumulator pressure corresponding to the calculated engine speed and the detected accelerator opening from the map indicating target accumulator pressures corresponding to the engine speeds and accelerator openings. The target accumulator pressure is used as the first threshold value.

[0031] The determination section 120 also determines whether the upstream pressure value is less than a predetermined second threshold value when the downstream pressure value is less than the first threshold value. The second threshold value is, for example, a pressure value determined depending on the engine speed. The second threshold value is set based on the results of experiments, simulations, and the like conducted in advance.

[0032] The input section 110 may receive the second threshold value from another device (e.g., a control unit), or the determination section 120 may calculate the second threshold value. The calculation by the determination section 120 is, for example, as follows. The input section 110 receives a detected value from a crank angle sensor (not shown). The determination section 120 then calculates the engine speed based on the detected crank angle. The determination section 120 then determines a pressure corresponding to the calculated engine speed from the map indicating the pressures corresponding to the engine speeds. The pressure is used as the second threshold value.

[0033] If the upstream pressure value is below the second threshold, the determination section 120 determines that a malfunction has occurred on the upstream side of the fuel pump 5 (e.g., the fuel filter 4 or a line (or lines) between the fuel tank 2 and the fuel pump 5).

[0034] On the other hand, when the upstream pressure value is equal to or greater than the second threshold value, the determination section 120 determines that a malfunction has occurred in the fuel pump 5.

[0035] The determination section 120 outputs or wirelessly transmits diagnosis result information indicating a location where the malfunction occurs (fuel pump 5 or the upstream side of the fuel pump 5) to a predetermined device.

[0036] The specified device may, for example, be a display or storage device installed in the vehicle or a server device installed outside the vehicle.

[0037] The diagnostic result information output to the storage device or server device is used, for example, by the manufacturer of the malfunctioning device or by the repair shop that repairs or replaces the malfunctioning device. For example, if the specified device is a server device, the diagnostic result information is transmitted from the server device to a repair shop terminal, allowing the repair shop to determine the location of the malfunction before the vehicle to be repaired is driven in.

[0038] This is the end of the description for the fuel supply system 1 and the fault diagnosis device 100.

[0039] The operation of the fault diagnosis device 100 will now be described with reference to Fig. 2 described. Fig. 2 illustrates an exemplary operation of the fault diagnosis device 100.

[0040] The input section 110 receives a downstream pressure value from the first pressure sensor 9 and an upstream pressure value from the second pressure sensor 10 (step S11).

[0041] The determination section 120 then determines whether the downstream pressure value is less than a first threshold value (step S12).

[0042] If the downstream pressure value is equal to or greater than the first threshold value (step S12: NO), the flow stops.

[0043] On the other hand, if the downstream pressure value is smaller than the first threshold value (step S12: YES), determining section 120 determines whether the upstream pressure value is smaller than a second threshold value (step S13).

[0044] If the upstream pressure value is smaller than the second threshold value (step S13: YES), the determination section 120 determines whether a malfunction has occurred on the upstream side of the fuel pump 5 (step S14).

[0045] On the other hand, when the value of the upstream pressure is equal to or greater than the second threshold value (step S13: NO), the determination section 120 determines that a malfunction has occurred at the fuel pump 5 (step S15).

[0046] The determination section 120 then outputs the diagnosis result information indicating the determination result or wirelessly transmits it to a predetermined device.

[0047] This is the end of the description for the operation of the fault diagnosis device 100.

[0048] As described in detail above, the failure diagnosis device 100 of the present embodiment determines whether the upstream pressure value is less than the second threshold when the downstream pressure value is less than the first threshold. The failure diagnosis device 100 determines that a malfunction has occurred on the upstream side of the fuel pump 5 when the upstream pressure value is less than the second threshold, and that the malfunction has occurred at the fuel pump 5 when the upstream pressure value is equal to or greater than the second threshold. When a malfunction occurs in the fuel supply system 1, the location of the malfunction in the fuel supply system 1 can be determined without having to disassemble the fuel supply system 1 for inspection.This reduces time and costs compared to identifying the location of the malfunction by disassembly.

[0049] The present disclosure is not limited to the above-described embodiment and can be appropriately modified and implemented without departing from the spirit of the present disclosure. The modifications are described below. [Modification 1]

[0050] The fault diagnosis device 100 is mounted on a vehicle as an example in the embodiment, but the fault diagnosis device 100 may also be mounted outside the vehicle.

[0051] For example, in this modification, a wireless communication device installed in a vehicle (e.g., a device used in telematics) wirelessly transmits an upstream pressure value received from the first pressure sensor 9 and a downstream pressure value received from the second pressure sensor 10 to the fault diagnosis device 100 via a predetermined network. The fault diagnosis device 100 uses the received upstream pressure value and the received downstream pressure value to perform the determination processes described above. [Modification 2]

[0052] The fuel supply system 1 described in the embodiment can be configured so that fuel can be supplied to an injector for injecting the fuel into an exhaust pipe (hereinafter referred to as an exhaust pipe injector).

[0053] For example, a branch pipe is provided that branches off from one of the pipes connecting the fuel tank 2 and the fuel pump 5, and the branch pipe is connected to the exhaust pipe injector in this modification. In this modification, fuel can be supplied to the exhaust pipe injector via the branch pipe.

[0054] The branch line may be provided, for example, on the upstream side or the downstream side of the fuel filter 4.

[0055] Additionally, the branch line may be equipped with a shutoff valve, a third pressure sensor, a metering valve, a fourth pressure sensor, and an exhaust pipe injector, in that order. The third pressure sensor detects the fuel pressure between the shutoff valve and the metering valve. The fourth pressure sensor detects the fuel pressure between the metering valve and the exhaust pipe injector. The pressure value detected by the third pressure sensor or the fourth pressure sensor may be used instead of the pre-pressure value described above. [Modification 3]

[0056] If it is determined that a malfunction has occurred on the upstream side of the fuel pump 5 in the embodiment, the location of the malfunction on the upstream side of the fuel pump 5 can be further determined. This modification will be described below.

[0057] A fifth pressure sensor for detecting the fuel pressure is further provided on a side downstream of the feed pump 3 and upstream of the fuel filter 4 in the Fig. 1 shown fuel supply system 1.

[0058] The input section 110 receives, in addition to the downstream pressure value and the upstream pressure value described above, a pressure value detected by the fifth pressure sensor (hereinafter referred to as the most upstream pressure value).

[0059] If it is determined that a malfunction has occurred on the upstream side of the fuel pump 5, the determination section 120 determines whether the most upstream pressure value is less than a third threshold value. The third threshold value is, for example, a pressure value determined depending on the engine speed.

[0060] If the most upstream pressure value is less than the third threshold value, the determination section 120 determines that a malfunction has occurred on the upstream side of the fuel filter 4 (e.g., at the feed pump 3 or in the lines between the fuel tank 2 and the fuel filter 4).

[0061] On the other hand, when the most upstream pressure value is equal to or greater than the third threshold, the determination section 120 determines that a malfunction has occurred in the fuel filter 4.

[0062] The determination section 120 then outputs or wirelessly transmits information about the diagnosis result indicating a location where the malfunction occurs (fuel filter 4 or the upstream side of fuel filter 4) to a predetermined device.

[0063] The present modification is thus able to identify the location of a malfunction on the upstream side of the fuel pump 5.

[0064] This concludes the description of modifications. Each modification can be performed in combination if necessary.

[0065] This application is based on Japanese Patent Application No. 2018-054326, filed on March 22, 2018, the contents of which are incorporated herein by reference. Industrial applicability

[0066] The fault diagnosis apparatus and method of diagnosing a malfunction of the present disclosure are particularly advantageous for identifying the location of the malfunction in a fuel supply system. List of reference symbols 1 fuel supply system 2 fuel tank 3 feed pump 4 fuel filters 5 Fuel pump 6 Flow control valve 7 High pressure pump 8 pressure accumulators 9 First pressure sensor 10 Second pressure sensor 100 Device for fault diagnosis 110 The entrance section 120 Investigation Section

Claims

[1] A fault diagnosis device comprising: an input section that receives a downstream pressure value, an upstream pressure value, and a most upstream pressure value in a fuel supply system, wherein the downstream pressure value is detected on a downstream side of a fuel pump that pressurizes and discharges fuel pumped up by a feed pump from a storage section in the fuel supply system, wherein the upstream pressure value is detected on an upstream side of the fuel pump, the most upstream pressure value is detected on an upstream side of a fuel filter and a downstream side of the feed pump, wherein the fuel filter is provided on an upstream side of the fuel pump, the fuel filter trapping foreign matter contained in the fuel; a determination section which, when the downstream pressure value is below a preset first threshold, determines whether the upstream pressure value is below a preset second threshold, and which, when the upstream pressure value is less than the preset second threshold, determines whether the most upstream pressure value is less than a preset third threshold, wherein the preset third threshold is determined depending on a rotational speed of an internal combustion engine, wherein the determining section determines that a malfunction has occurred on the upstream side of the fuel pump when the upstream pressure value is less than the second threshold value, the determination section determines that a malfunction has occurred in the fuel pump if the value of the pressure upstream of the pump is equal to or greater than the second threshold value, the determination section determines that a malfunction has occurred on an upstream side of the fuel filter when the most upstream pressure value is less than the third threshold value, the determination section determines that a malfunction has occurred in the fuel filter if the most upstream pressure value is equal to or greater than the third threshold value, and the determining section outputs information about the diagnosis result to a predetermined device indicating a location where the malfunction occurs. [2] A fault diagnosis device according to claim 1, wherein: the downstream pressure value is a pressure value of the fuel in a pressure accumulator that stores the fuel delivered by the fuel pump under pressure. [3] A fault diagnosis device according to claim 1, wherein: the upstream pressure value is a pressure value of the fuel flowing between the fuel pump and the fuel filter. [4] A fault diagnosis device according to claim 1, wherein: the fuel pump includes a flow control valve that adjusts a flow rate of the fuel, and a high-pressure pump that pressurizes the fuel and whose flow rate is adjusted. [5] The fault diagnosis device according to claim 1, wherein the upstream side of the fuel filter is a position on the feed pump or on lines between the storage section and the fuel filter. [6] The procedure for diagnosing a malfunction includes: Receiving a downstream pressure value, an upstream pressure value, and a most upstream pressure value in a fuel supply system, wherein the downstream pressure value is detected on a downstream side of a fuel pump that pressurizes and discharges fuel pumped up from a storage section in the fuel supply system by a feed pump, wherein the upstream pressure value is detected on an upstream side of the fuel pump, the most upstream pressure value is detected on an upstream side of a fuel filter and a downstream side of the feed pump, wherein the fuel filter is provided on an upstream side of the fuel pump, the fuel filter trapping foreign matter contained in the fuel; determining, if the downstream pressure value is less than a preset first threshold, whether the upstream pressure value is less than a preset second threshold; determining, if the upstream pressure value is less than the preset second threshold, whether the most upstream pressure value is less than a preset third threshold, wherein the preset third threshold is determined depending on a speed of an internal combustion engine; Determining that a malfunction has occurred on the upstream side of the fuel pump when the upstream pressure value is less than the second threshold, and determining that a malfunction has occurred on the fuel pump when the upstream pressure value is equal to or greater than the second threshold; Determining that a malfunction has occurred on an upstream side of the fuel filter when the most upstream pressure value is less than the third threshold, and Determining that a fuel filter malfunction has occurred when the most upstream pressure value is equal to or greater than the third threshold; and Outputting information about the diagnosis result to a predetermined device indicating a location where the malfunction occurs.

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