Egr failure detection method and device

Abstract

The application provides an EGR fault detection method and device, belonging to the technical field of automobile engine detection, selects multiple EGR test working points most likely to cause EGR faults from all possible EGR working points, and determines the test duration required for each test working point, controls the engine operation and the opening of the EGR based on the determined test duration in the subsequent test process, obtains the actual parameters of the EGR corresponding to each test working point, compares the actual parameters with the ideal parameters stored in advance, judges whether the EGR has faults according to the comparison result, thereby effectively detecting the EGR faults, and enables the maintenance personnel to timely maintain the EGR according to the faults, so that further damage to the vehicle is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of automobile engine detection, and in particular to an EGR fault detection method and device. Background Art

[0002] Exhaust Gas Recirculation (EGR) refers to a technology that cools a portion of the exhaust gases from a vehicle's combustion engine before introducing them into the intake system for re-combustion. While most engine exhaust gases cannot be burned, they have a high specific heat capacity and strong heat absorption capacity. After being cooled and introduced into the intake system, they can lower the maximum combustion temperature of the mixture in the cylinder, reducing the engine's tendency to knock. Furthermore, introducing exhaust gases into the intake system can reduce oxygen concentration, significantly reducing the production of nitrogen oxides. Furthermore, using EGR under low engine load conditions can reduce intake pumping losses, thereby reducing fuel consumption.

[0003] However, when using EGR in low-speed and low-load areas, due to the low exhaust temperature, the EGR rate is not high, and the water temperature has not reached the target water temperature. The gas temperature after EGR cooling is low, and mixed pollutants such as soot in the exhaust gas are more easily adsorbed on the heat exchange surface of the EGR cooler, resulting in serious carbon accumulation on the gas-side heat exchange surface of the EGR cooler after long-term use. Pollutants such as carbon deposits entering the EGR valve will further cause the EGR valve to become stuck. In addition, if the soot particulate matter emission content is high and the exhaust gas flow rate is large at a certain operating point, there is also the possibility of accelerated adsorption rate leading to blockage. Moreover, when applying EGR to hybrid vehicles, since the hybrid vehicle engine mostly operates in the high thermal efficiency area, the EGR adjustment opening range is small, and the gears in the EGR valve assembly work in the same area for a long time most of the time, so there is also a risk of abnormal wear.

[0004] The above EGR sticking and wear phenomena will lead to EGR failure, seriously affecting the energy-saving and emission-reduction effect of the EGR system, causing vehicle emissions to exceed the standard, and in severe cases may also cause damage to engine parts. Summary of the Invention

[0005] In view of this, the present application provides an EGR fault detection method and device, which can effectively detect EGR faults.

[0006] Specifically, the following technical solutions are included:

[0007] In a first aspect, the present application provides an EGR fault detection method, the method comprising:

[0008] A plurality of EGR test operating points that meet the operating conditions are selected from all EGR operating points included in the first correspondence table.

[0009] A plurality of preset test durations corresponding to the plurality of EGR test operating points are determined.

[0010] Based on a plurality of EGR test operating points and a plurality of preset test durations corresponding to the plurality of EGR test operating points, the engine operation is controlled and the EGR opening is controlled simultaneously.

[0011] The corresponding actual EGR parameters are obtained at each EGR test operating point of the engine.

[0012] Compare the actual parameters with the pre-stored ideal parameters.

[0013] The comparison between the actual parameters and the pre-stored ideal parameters determines whether there is an EGR fault.

[0014] Optionally, the first correspondence table stores correspondences between different speeds, different torques, and different EGR openings, and multiple EGR test operating points that meet the operating conditions are selected from all EGR operating points included in the first correspondence table, including:

[0015] From the first correspondence table, multiple EGR test operating points corresponding to the EGR opening within the first preset range, the EGR test operating point corresponding to the maximum EGR rate, and the EGR test operating point corresponding to the operating condition with the maximum estimated exhaust particulate matter amount are selected. Each EGR test operating point is represented by a set of torque and speed.

[0016] Optionally, determining a plurality of preset test durations corresponding to a plurality of EGR test operating points includes:

[0017] From the second correspondence table between torque, speed and preset test time, multiple preset test time periods corresponding to multiple EGR test operating points are selected, wherein the second correspondence table stores the correspondence between different speeds, different torques and different preset test time periods, and each EGR test operating point is represented by a set of torque and speed.

[0018] Optionally, based on a plurality of EGR test operating points and a plurality of preset test durations corresponding to the plurality of EGR test operating points, controlling the engine operation and simultaneously controlling the EGR opening degree includes:

[0019] The engine is controlled to operate for the corresponding preset test time in sequence based on the torque and speed corresponding to each EGR test operating point in multiple EGR test operating points, and is stopped for the first interval time after each cumulative operation of the engine for the first operating time, until the cumulative operation of the engine reaches the preset total time.

[0020] Optionally, obtaining corresponding actual EGR parameters at each EGR test operating point of the engine includes:

[0021] At each EGR test operating point during engine operation, obtain the corresponding actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the actual temperature of the gas before the EGR valve, and the actual temperature of the gas after the EGR valve.

[0022] Comparing actual parameters with pre-stored ideal parameters includes:

[0023] The actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the gas temperature before the EGR valve and the gas temperature after the EGR valve are compared with the pre-stored ideal pressure upstream of the EGR valve, the ideal pressure downstream of the EGR valve, the ideal gas temperature before the EGR valve and the ideal gas temperature after the EGR valve.

[0024] In a second aspect, the present application further provides an EGR fault detection device, comprising:

[0025] The operating condition selection module is configured to select a plurality of EGR test operating condition points that meet the operating condition from all EGR operating condition points included in the first correspondence table.

[0026] The time determination module is configured to determine a plurality of preset test durations corresponding to a plurality of EGR test operating points.

[0027] The operation control module is configured to control the engine operation and the EGR opening degree based on a plurality of EGR test operating points and a plurality of preset test durations corresponding to the plurality of EGR test operating points.

[0028] The parameter acquisition module is configured to acquire the corresponding actual EGR parameters at each EGR test operating point of the engine.

[0029] The parameter comparison module is configured to compare the actual parameters with the pre-stored ideal parameters.

[0030] The fault judgment module is configured to judge whether there is a fault in the EGR according to the comparison result of the actual parameters and the pre-stored ideal parameters.

[0031] Optionally, the first correspondence table stores correspondences between different speeds, different torques, and different EGR openings, and the operating condition selection module is configured as follows:

[0032] From the first correspondence table, multiple EGR test operating points corresponding to the EGR opening within the first preset range, the EGR test operating point corresponding to the maximum EGR rate, and the EGR test operating point corresponding to the operating condition with the maximum estimated exhaust particulate matter amount are selected. Each EGR test operating point is represented by a set of torque and speed.

[0033] Optionally, the time determination module is configured to:

[0034] From the second correspondence table between torque, speed and preset test time, multiple preset test time periods corresponding to multiple EGR test operating points are selected, wherein the second correspondence table stores the correspondence between different speeds, different torques and different preset test time periods, and each EGR test operating point is represented by a set of torque and speed.

[0035] Optionally, the operation control module is configured to:

[0036] The engine is controlled to operate for the corresponding preset test time in sequence based on the torque and speed corresponding to each EGR test operating point in multiple EGR test operating points, and is stopped for the first interval time after each cumulative operation of the engine for the first operating time, until the cumulative operation of the engine reaches the preset total time.

[0037] Optionally, the parameter acquisition module is configured to:

[0038] At each EGR test operating point during engine operation, the corresponding actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the actual temperature of the gas before the EGR valve, and the actual temperature of the gas after the EGR valve are obtained.

[0039] The parameter comparison module is configured as follows:

[0040] The actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the gas temperature before the EGR valve and the gas temperature after the EGR valve are compared with the pre-stored ideal pressure upstream of the EGR valve, the ideal pressure downstream of the EGR valve, the ideal gas temperature before the EGR valve and the ideal gas temperature after the EGR valve.

[0041] By using the EGR fault detection method and device provided by the present application, multiple EGR test operating points that are most likely to cause EGR failure are selected from all possible EGR operating points, and the test time required for each test operating point is determined. In the subsequent test process, the engine operation is controlled based on the determined test time and the EGR opening is controlled at the same time, and the actual EGR parameters corresponding to each test operating point are obtained and compared with the pre-stored ideal parameters. According to the comparison results, it is determined whether there is an EGR fault, thereby effectively detecting the EGR fault and enabling maintenance personnel to repair the EGR in time according to the fault to avoid further damage to the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0043] Figure 1 A flow chart of an EGR fault detection method provided in an embodiment of the present application;

[0044] Figure 2 Another flow chart of the EGR fault detection method provided in an embodiment of the present application;

[0045] Figure 3 A schematic diagram of the sensor installation position of the EGR fault detection method provided in an embodiment of the present application;

[0046] Figure 4 This is a structural diagram of the EGR fault detection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0048] The embodiment of the present application provides an EGR fault detection method that can effectively detect EGR faults. The method can be executed using a processing device of a test bench, such as Figure 1 As shown, the method includes steps S101, S102, S103, S104, S105 and S106, wherein:

[0049] In step S101 , a plurality of EGR test operating points that meet the operating conditions are selected from all EGR operating points included in the first correspondence table.

[0050] In step S102 , a plurality of preset test durations corresponding to a plurality of EGR test operating points are determined.

[0051] In step S103 , based on a plurality of EGR test operating points and a plurality of preset test durations corresponding to the plurality of EGR test operating points, the engine operation is controlled and the EGR opening is controlled simultaneously.

[0052] In step S104, corresponding actual EGR parameters are obtained at each EGR test operating point of the engine.

[0053] In step S105 , the actual parameters are compared with pre-stored ideal parameters.

[0054] In step S106 , it is determined whether there is an EGR fault based on a comparison result between the actual parameters and the pre-stored ideal parameters.

[0055] In some optional embodiments, the first correspondence table stores correspondences between different speeds, different torques, and different EGR openings, and selecting multiple EGR test operating points that meet the operating conditions from all EGR operating points included in the first correspondence table includes:

[0056] From the first correspondence table, multiple EGR test operating points corresponding to the EGR opening within the first preset range, the EGR test operating point corresponding to the maximum EGR rate, and the EGR test operating point corresponding to the operating condition with the maximum estimated exhaust particulate matter amount are selected. Each EGR test operating point is represented by a set of torque and speed.

[0057] In some optional embodiments, determining a plurality of preset test durations corresponding to a plurality of EGR test operating points includes:

[0058] From the second correspondence table between torque, speed and preset test time, multiple preset test time periods corresponding to multiple EGR test operating points are selected, wherein the second correspondence table stores the correspondence between different speeds, different torques and different preset test time periods, and each EGR test operating point is represented by a set of torque and speed.

[0059] In some optional embodiments, based on a plurality of EGR test operating points and a plurality of preset test durations corresponding to the plurality of EGR test operating points, controlling the engine operation and simultaneously controlling the EGR opening degree includes:

[0060] The engine is controlled to operate for the corresponding preset test time in sequence based on the torque and speed corresponding to each EGR test operating point in multiple EGR test operating points, and is stopped for the first interval time after each cumulative operation of the engine for the first operating time, until the cumulative operation of the engine reaches the preset total time.

[0061] In some optional embodiments, obtaining corresponding actual EGR parameters at each EGR test operating point of the engine includes:

[0062] At each EGR test operating point during engine operation, the corresponding actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the actual temperature of the gas before the EGR valve, and the actual temperature of the gas after the EGR valve are obtained.

[0063] Comparing actual parameters with pre-stored ideal parameters includes:

[0064] The actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the gas temperature before the EGR valve and the gas temperature after the EGR valve are compared with the pre-stored ideal pressure upstream of the EGR valve, the ideal pressure downstream of the EGR valve, the ideal gas temperature before the EGR valve and the ideal gas temperature after the EGR valve.

[0065] By adopting the EGR fault detection method provided by the present application, multiple EGR test operating points that are most likely to cause EGR failure are selected from all possible EGR operating points, and the test time required for each test operating point is determined. In the subsequent test process, the engine operation is controlled based on the determined test time and the EGR opening is controlled at the same time, and the actual EGR parameters corresponding to each test operating point are obtained and compared with the pre-stored ideal parameters. It is judged whether there is an EGR fault based on the comparison results, thereby effectively detecting the EGR fault and enabling maintenance personnel to repair the EGR in time according to the fault to avoid further damage to the vehicle.

[0066] The embodiment of the present application also provides another EGR fault detection method, which can effectively detect EGR faults. The method can be executed using a processing device of a test bench, such as Figure 2 As shown, the method includes steps S201, S202, S203, S204, S205, S206 and S207, wherein:

[0067] In step S201 , a plurality of EGR test operating points that meet the operating conditions are selected from all EGR operating points included in the first correspondence table.

[0068] In some optional embodiments, the EGR targeted by the EGR fault detection method provided by the present application is low-pressure EGR.

[0069] Table 1 below is an example of the first relationship table.

[0070] Table 1:

[0071]

[0072] It is understood that since EGR is used to recirculate exhaust gas from the engine, the EGR opening is related to engine operating parameters, such as engine speed and torque. A specific set of engine speeds and torques corresponds to a specific EGR opening value, and this correspondence can be stored in a first relationship table. This table stores the correspondence between different speeds, different torques, and different EGR openings, with speed as the horizontal axis and torque as the vertical axis. A space in the table corresponding to a set of speeds and torques is filled with the EGR opening value corresponding to that set of speeds and torques, and this space is considered an EGR operating point.

[0073] For example, in Table 1, the space corresponding to a speed value of 200 and a torque value of 60 is filled with an EGR opening of 6. Therefore, the corresponding speed value for this EGR operating point is 200, the torque value is 60, and the corresponding EGR opening is 6. In Table 1, torque is expressed in Newton-meters, and speed is expressed in revolutions per minute. The EGR opening can be a number denoted by 0-47, with an EGR opening of 0 indicating the minimum EGR opening and an EGR opening of 47 indicating the maximum EGR opening.

[0074] It is understandable that Table 1 can be obtained after the EGR is assembled on the engine and calibrated together. A set of speed, torque and EGR opening can also correspond to a fuel consumption value, but the fuel consumption value is not reflected in the above table.

[0075] While EGR operates at numerous operating points, not every point is prone to EGR failure. Only specific EGR operating points that meet the required operating conditions are prone to EGR failure. Therefore, to improve testing efficiency, it's necessary to pre-screen those EGR operating points prone to EGR failure from among all available EGR operating points as EGR test points. Before testing, product development teams should discuss potential EGR risk points, list key failure modes, and identify interfering factors. For example, soot deposits leading to sticking, or small openings leading to wear, will help determine the principles for selecting EGR operating points.

[0076] When using EGR in low-speed and low-load areas, due to the low exhaust temperature, the EGR rate is not high, and the water temperature has not reached the target water temperature. The gas temperature after EGR cooling is low, and mixed pollutants such as carbon soot in the exhaust gas are more easily adsorbed on the heat exchange surface of the EGR cooler, resulting in serious carbon accumulation on the gas side heat exchange surface of the EGR cooler after long-term use. Pollutants such as carbon deposits entering the EGR valve will further cause the EGR valve to stick. Therefore, it is necessary to select the EGR test operating point corresponding to the operating condition with the largest estimated amount of exhaust particulate matter.

[0077] It is understood that an estimated exhaust particulate matter amount corresponding to a set of speed, torque, and EGR opening can also be stored. For example, the EGR test operating point corresponding to the operating condition with the maximum estimated exhaust particulate matter amount selected in Table 1 is the EGR operating point corresponding to a speed of 3500 and a torque of 107. At this EGR operating point, the EGR opening is 28.

[0078] Furthermore, if soot particulate matter emissions are high and exhaust gas flow is high at a certain operating point, there's a possibility of accelerated adsorption leading to blockage. Therefore, it's also necessary to select an EGR test operating point corresponding to the maximum EGR rate. For example, the EGR test operating point corresponding to the maximum EGR rate selected in Table 1 is the EGR operating point corresponding to a speed of 2500 and a torque of 95. At this EGR operating point, the EGR opening is 47°. The EGR rate is the ratio of the amount of exhaust gas recirculated to the total amount of intake air drawn into the cylinder.

[0079] Furthermore, when applying EGR to hybrid vehicles, since hybrid engines primarily operate in a high-thermal-efficiency range, the EGR adjustment range is narrow. The gears in the EGR valve assembly operate within the same range for extended periods of time. When the EGR valve is narrowly opened, the airflow impact on both sides of the valve core is maximized, leading to the greatest risk of wear on the motor gears and the risk of abnormal wear. Therefore, it is necessary to select multiple EGR test operating points corresponding to a first preset EGR opening range. The first preset EGR opening range can be [3, 6], within which the EGR presents a risk of abnormal wear.

[0080] In step S202 , a plurality of preset test durations corresponding to a plurality of EGR test operating points are determined.

[0081] In some optional embodiments, determining a plurality of preset test durations corresponding to a plurality of EGR test operating points includes:

[0082] From a second correspondence table between torque, speed, and preset test durations, multiple preset test durations corresponding to multiple EGR test operating points are selected. The second correspondence table stores correspondences between different speeds, different torques, and different preset test durations, with each EGR test operating point represented by a set of torque and speed. The second correspondence table is shown in Table 2.

[0083] Table 2:

[0084]

[0085] The unit of torque in Table 2 is Nm, and the unit of speed is revolutions per minute.

[0086] It's understood that the Worldwide Harmonized Light Vehicles Test Cycle (WLTC) is an automotive emissions testing standard used to measure real-world fuel economy and emissions under various driving conditions, such as city and highway driving. In the WLTC test, each set of engine speed and torque represents an engine operating point, and each engine operating point is associated with a specific test duration, indicating the length of time the engine must run at that operating point. It's understood that the total WLTC test duration is fixed, for example, 1800 seconds. Therefore, Table 2 may simply record the test time for each operating point as a percentage of the total test time.

[0087] In step S201, multiple EGR test operating points that meet the operating conditions have been determined. These EGR test operating points are also represented by multiple speed and torque pairs. Therefore, by substituting these multiple speed and torque pairs into Table 2, we can obtain multiple preset test durations corresponding to each of these EGR test operating point pairs. For example, the EGR test operating point corresponding to the maximum EGR rate is 2500 speed and 95 torque. Substituting this EGR test operating point into Table 2 yields a corresponding preset test duration of 0.61% multiplied by the total WLTC test time.

[0088] It is understandable that incorporating the WLTC test time into the EGR fault test can better fit the actual situation and more accurately determine the EGR fault condition.

[0089] In step S203 , based on a plurality of EGR test operating points and a plurality of preset test durations corresponding to the plurality of EGR test operating points, the engine operation is controlled and the EGR opening is controlled simultaneously.

[0090] In some optional embodiments, because more condensed water during shutdown increases the likelihood of soot deposition, the method provided in the embodiments of the present application utilizes shutdown cooling to accelerate soot deposition, shorten the verification cycle, and reduce development costs. Specifically, step S203 includes controlling the engine to sequentially operate for a corresponding preset test duration based on the torque and speed corresponding to each of the multiple EGR test operating points, and shutting the engine down for a first interval after each cumulative operation time, until the engine reaches a preset total cumulative operation time.

[0091] It can be understood that in order to shorten the verification cycle, the engine in the embodiment of the present application is operated periodically, that is, it runs for a first running time and then stops for a first interval time, and then starts again, over and over again until the cumulative operation reaches a preset total time, thereby simulating the normal shutdown cooling condition of the engine and accelerating carbon soot deposition.

[0092] In some optional embodiments, the order of sequentially running the corresponding preset test durations may be to first run the preset test duration for the EGR test operating point corresponding to the operating condition with the maximum estimated exhaust particulate matter amount, then run the preset test duration for the EGR test operating point corresponding to the maximum EGR rate, and then run the preset test durations for multiple EGR test operating points corresponding to EGR openings within a first preset range. In some optional embodiments, the first run time may be 180 seconds, and the first interval time may be 15 seconds.

[0093] In step S204, corresponding actual EGR parameters are obtained at each EGR test operating point of the engine.

[0094] In some optional embodiments, obtaining corresponding actual EGR parameters at each EGR test operating point of the engine includes:

[0095] At each EGR test operating point during engine operation, the corresponding actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the actual temperature of the gas before the EGR valve, and the actual temperature of the gas after the EGR valve are obtained.

[0096] In some optional embodiments, press Figure 3 An EGR valve upstream pressure sensor 301 , an EGR valve downstream pressure sensor 302 , an EGR valve post-gas temperature sensor 303 and an EGR valve pre-gas temperature sensor 304 are arranged at the middle measurement position to obtain the measured relevant actual parameter values.

[0097] In step S205 , the actual parameters are compared with the pre-stored ideal parameters.

[0098] Step S205 includes comparing the actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the gas temperature before the EGR valve, and the gas temperature after the EGR valve with the pre-stored ideal pressure upstream of the EGR valve, the ideal pressure downstream of the EGR valve, the ideal gas temperature before the EGR valve, and the ideal gas temperature after the EGR valve.

[0099] In step S206 , it is determined whether there is an EGR fault based on the comparison result between the actual parameters and the pre-stored ideal parameters.

[0100] In some optional embodiments, the numerical changes of the engine speed, torque and EGR opening during the test process can be printed to obtain a change line graph, thereby facilitating the monitoring of the test conditions.

[0101] In some optional embodiments, a deviation ratio may be set. When the ratio of the absolute value of the difference between the actual parameter and the ideal parameter to the ideal parameter is greater than the deviation ratio, it is determined that there is a fault in the EGR.

[0102] In some optional embodiments, in addition to real-time monitoring of EGR parameters during the test and determining whether a fault has occurred, other parameters before and after the EGR test may be compared to determine whether the EGR durability meets requirements after long-term testing. Therefore, prior to all steps, the method may further include obtaining original auxiliary parameters of the EGR, including EGR opening response time, closing response time, failsafe response time, initial voltage, full-open voltage, leakage, cooler liquid-side leakage, cooler gas-side leakage, and EGR module leakage, and pre-storing these original auxiliary parameters.

[0103] In step S207 , updated auxiliary parameters of the EGR after the test are obtained, and the updated auxiliary parameters are compared and analyzed with the original auxiliary parameters pre-stored before the test, so as to determine whether the durability of the EGR after the test meets the durability requirement.

[0104] In some optional embodiments, the fuel consumption corresponding to each EGR test operating point before and after the test can also be compared and analyzed, so as to judge whether EGR has a significant impact on reducing fuel consumption after long-term testing based on the change in fuel consumption, thereby indirectly judging whether the durability of EGR meets the requirements.

[0105] In some optional embodiments, during the entire test process, a recording device is used to record the engine speed, torque, power, oil pressure, oil temperature, inlet and outlet water temperature, inlet and outlet water pressure, exhaust back pressure and crankcase pressure, with a recording frequency of once per second.

[0106] In some optional embodiments, the engine speed, load, EGR valve target opening, EGR valve actual opening, EGR feedback voltage, EGR drive voltage, EGR duty cycle, EGR valve upstream pressure, EGR valve downstream pressure, EGR valve before gas temperature and EGR valve after gas temperature are recorded every 100 hours during the test.

[0107] The EGR fault detection method provided in this application selects multiple EGR test operating points that are most likely to cause EGR failure from all possible EGR operating points, and determines the test duration required for each test operating point. During subsequent testing, the engine operation and the EGR opening are controlled based on the determined test duration. The actual EGR parameters corresponding to each test operating point are obtained and compared with the pre-stored ideal parameters. Based on the comparison results, it is determined whether the EGR is faulty, thereby effectively detecting EGR faults and enabling maintenance personnel to promptly repair the EGR based on the fault. After the test is completed, other parameters before and after the test are compared to evaluate the durability of the EGR after the test.

[0108] The embodiment of the present application also provides an EGR fault detection device, which is arranged in a processing device of a test bench, such as Figure 4 As shown, the device includes:

[0109] The operating condition selection module 401 is configured to select a plurality of EGR test operating condition points that meet the operating condition from all EGR operating condition points included in the first correspondence table.

[0110] The time determination module 402 is configured to determine a plurality of preset test durations corresponding to a plurality of EGR test operating points.

[0111] The operation control module 403 is configured to control the engine operation and the EGR opening degree based on a plurality of EGR test operating points and a plurality of preset test durations corresponding to the plurality of EGR test operating points.

[0112] The parameter acquisition module 404 is configured to acquire corresponding actual EGR parameters at each EGR test operating point of the engine.

[0113] The parameter comparison module 405 is configured to compare the actual parameters with the pre-stored ideal parameters.

[0114] The fault determination module 406 is configured to determine whether there is a fault in the EGR according to a comparison result between the actual parameters and the pre-stored ideal parameters.

[0115] In some optional embodiments, the first correspondence table stores correspondences between different speeds, different torques, and different EGR openings, and the operating condition selection module 401 is configured as follows:

[0116] From the first correspondence table, multiple EGR test operating points corresponding to the EGR opening within the first preset range, the EGR test operating point corresponding to the maximum EGR rate, and the EGR test operating point corresponding to the operating condition with the maximum estimated exhaust particulate matter amount are selected. Each EGR test operating point is represented by a set of torque and speed.

[0117] In some optional embodiments, the time determination module 402 is configured to:

[0118] From the second correspondence table between torque, speed and preset test time, multiple preset test time periods corresponding to multiple EGR test operating points are selected, wherein the second correspondence table stores the correspondence between different speeds, different torques and different preset test time periods, and each EGR test operating point is represented by a set of torque and speed.

[0119] In some optional embodiments, the operation control module 403 is configured to:

[0120] The engine is controlled to operate for the corresponding preset test time in sequence based on the torque and speed corresponding to each EGR test operating point in multiple EGR test operating points, and is stopped for the first interval time after each cumulative operation of the engine for the first operating time, until the cumulative operation of the engine reaches the preset total time.

[0121] In some optional embodiments, the parameter acquisition 404 module is configured to:

[0122] At each EGR test operating point during engine operation, the corresponding actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the actual temperature of the gas before the EGR valve, and the actual temperature of the gas after the EGR valve are obtained.

[0123] The parameter comparison module 405 is configured to:

[0124] The actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the gas temperature before the EGR valve and the gas temperature after the EGR valve are compared with the pre-stored ideal pressure upstream of the EGR valve, the ideal pressure downstream of the EGR valve, the ideal gas temperature before the EGR valve and the ideal gas temperature after the EGR valve.

[0125] By using the EGR fault detection method and device provided by the present application, multiple EGR test operating points that are most likely to cause EGR failure are selected from all possible EGR operating points, and the test time required for each test operating point is determined. In the subsequent test process, the engine operation is controlled based on the determined test time and the EGR opening is controlled at the same time, and the actual EGR parameters corresponding to each test operating point are obtained and compared with the pre-stored ideal parameters. According to the comparison results, it is determined whether there is an EGR fault, thereby effectively detecting the EGR fault and enabling maintenance personnel to repair the EGR in time according to the fault to avoid further damage to the vehicle.

[0126] This embodiment and the method embodiment are based on the same inventive concept and are device embodiments corresponding to the method embodiment. Therefore, those skilled in the art should understand that the description of the method embodiment is also applicable to this embodiment, and some technical details are no longer described in detail in this embodiment.

[0127] In this application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features.

[0128] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only.

[0129] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

[0130] The above description is only for the purpose of facilitating those skilled in the art to understand the technical solution of this application and is not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included in the scope of protection of this application.

Claims

1. A method for detecting EGR faults, characterized in that: The method comprises: Selecting a plurality of EGR test operating points that meet the operating conditions from all EGR operating points included in the first correspondence table; Determining a plurality of preset test durations corresponding to the plurality of EGR test operating points respectively; Based on the multiple EGR test operating points and the multiple preset test durations corresponding to the multiple EGR test operating points, controlling the engine operation and simultaneously controlling the EGR opening; Obtaining corresponding actual parameters of the EGR at each EGR test operating point of the engine; Comparing the actual parameters with pre-stored ideal parameters; Determine whether the EGR has a fault based on the comparison result between the actual parameters and the pre-stored ideal parameters, The first correspondence table stores correspondences between different speeds, different torques, and different EGR openings. The selection of multiple EGR test operating points that meet the operating conditions from all EGR operating points included in the first correspondence table includes: From the first correspondence table, multiple EGR test operating points corresponding to the EGR opening within the first preset range, the EGR test operating point corresponding to the maximum EGR rate, and the EGR test operating point corresponding to the operating condition with the maximum estimated exhaust particulate matter amount are selected, each EGR test operating point being represented by a set of torque and speed. The determining of the plurality of preset test durations corresponding to the plurality of EGR test operating points comprises: From a second correspondence table between torque, speed and preset test duration, multiple preset test durations corresponding to the multiple EGR test operating points are selected, wherein the second correspondence table stores the correspondence between different speeds, different torques and different preset test durations, and each EGR test operating point is represented by a set of torque and speed.

2. The method according to claim 1, characterized in that The controlling the engine operation and the EGR opening degree simultaneously based on the multiple EGR test operating points and the multiple preset test durations corresponding to the multiple EGR test operating points includes: The engine is controlled to operate for the corresponding preset test time in sequence based on the torque and speed corresponding to each EGR test operating point among the multiple EGR test operating points, and the engine is stopped for the first interval time after each cumulative operation of the engine for the first operating time, until the cumulative operation of the engine reaches the preset total time.

3. The method according to claim 1, characterized in that Obtaining the corresponding actual parameters of the EGR at each EGR test operating point during engine operation includes: At each EGR test operating point of the engine, the corresponding actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the actual temperature of the gas before the EGR valve, and the actual temperature of the gas after the EGR valve are obtained. The comparing the actual parameters with the pre-stored ideal parameters includes: The actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the gas temperature before the EGR valve, and the gas temperature after the EGR valve are compared with the pre-stored ideal pressure upstream of the EGR valve, the ideal pressure downstream of the EGR valve, the ideal gas temperature before the EGR valve, and the ideal gas temperature after the EGR valve, respectively.

4. An EGR fault detection device, characterized in that: The device comprises: a working condition selection module configured to select a plurality of EGR test working condition points that meet the working condition from all EGR working condition points included in the first correspondence table; a time determination module configured to determine a plurality of preset test durations corresponding to the plurality of EGR test operating points; an operation control module configured to control the engine operation and simultaneously control the EGR opening based on the multiple EGR test operating points and the multiple preset test durations corresponding to the multiple EGR test operating points; A parameter acquisition module is configured to acquire corresponding actual parameters of the EGR at each EGR test operating point of the engine; a parameter comparison module, configured to compare the actual parameters with pre-stored ideal parameters; A fault judgment module is configured to judge whether the EGR has a fault based on the comparison result of the actual parameter and the pre-stored ideal parameter, The first correspondence table stores correspondences between different speeds, different torques, and different EGR openings. The operating condition selection module is configured as follows: From the first correspondence table, multiple EGR test operating points corresponding to the EGR opening within the first preset range, the EGR test operating point corresponding to the maximum EGR rate, and the EGR test operating point corresponding to the operating condition with the maximum estimated exhaust particulate matter amount are selected, each EGR test operating point being represented by a set of torque and speed. The time determination module is configured to: From a second correspondence table between torque, speed and preset test duration, multiple preset test durations corresponding to the multiple EGR test operating points are selected, wherein the second correspondence table stores the correspondence between different speeds, different torques and different preset test durations, and each EGR test operating point is represented by a set of torque and speed.

5. The device according to claim 4, characterized in that The operation control module is configured to: The engine is controlled to operate for the corresponding preset test time in sequence based on the torque and speed corresponding to each EGR test operating point among the multiple EGR test operating points, and the engine is stopped for the first interval time after each cumulative operation of the engine for the first operating time, until the cumulative operation of the engine reaches the preset total time.

6. The device according to claim 4, characterized in that The parameter acquisition module is configured as follows: At each EGR test operating point of the engine, the corresponding actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the actual temperature of the gas before the EGR valve, and the actual temperature of the gas after the EGR valve are obtained. The parameter comparison module is configured as follows: The actual pressure upstream of the EGR valve, the actual pressure downstream of the EGR valve, the gas temperature before the EGR valve, and the gas temperature after the EGR valve are compared with the pre-stored ideal pressure upstream of the EGR valve, the ideal pressure downstream of the EGR valve, the ideal gas temperature before the EGR valve, and the ideal gas temperature after the EGR valve, respectively.

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