Control method for an egr system and egr system

Abstract

The embodiment of the application discloses a kind of control method of exhaust gas recirculation EGR system and EGR system;Wherein, in EGR system, front stage exhaust pipe is connected to cooler by first pipeline, cooler is connected to EGR valve by second pipeline, EGR valve is connected to mixing valve by third pipeline, and, rear oxygen sensor is arranged in first pipeline, temperature sensor is arranged in second pipeline, water pump is connected to cooler using fourth pipeline and fifth pipeline, second pipeline and third pipeline are connected to differential pressure sensor using sixth pipeline and seventh pipeline respectively;Method includes: starting EGR system;Obtain the rear oxygen diagnostic value of rear oxygen sensor, the temperature diagnostic value of temperature sensor and the differential pressure diagnostic value of differential pressure sensor;Determine the leakage condition of at least one of first pipeline, second pipeline, third pipeline, fourth pipeline, fifth pipeline, sixth pipeline and seventh pipeline based on rear oxygen diagnostic value, temperature diagnostic value and differential pressure diagnostic value.

Description

Technical Field

[0001] This application relates to, but is not limited to, the field of automotive technology, and in particular to a control method for an EGR system and an EGR system. Background Technology

[0002] As emission and fuel consumption standards become increasingly stringent, exhaust gas recirculation (EGR) technology, as a cutting-edge technology for reducing fuel consumption and emissions, is gradually being adopted by major OEMs.

[0003] EGR technology refers to the technology of reintroducing a portion of the exhaust gases from the engine into the intake system, where they are mixed with fresh air or a fuel-air mixture and reintroduced into the cylinders for combustion. The principle behind EGR is that engine exhaust contains a large amount of non-combustible inert gases such as carbon dioxide (CO2). Because these inert gases have high specific heat capacities and can absorb a significant amount of heat, they can lower the peak combustion temperature of the air-fuel mixture in the cylinder. Simultaneously, introducing the exhaust gases into the cylinder reduces the oxygen concentration, thereby slowing down the combustion rate. This lowers both the peak and average combustion temperatures, thus reducing the formation of nitrogen oxides (NOx). x The generation conditions of NO are reduced, thereby greatly reducing NO. x The generation of these pollutants meets the current relatively strict emission standards.

[0004] In addition, introducing EGR technology under low engine load conditions can reduce intake pumping losses and reduce fuel consumption; at the same time, due to the reduction in the maximum combustion temperature, the tendency of engine knocking is significantly improved, which helps to increase the engine compression ratio and ignition advance, further improving fuel consumption.

[0005] The application of low-pressure EGR systems has made the layout and piping of the intake system more complex. Therefore, how to effectively and accurately control the normal operation of the EGR system has become an urgent problem to be solved. Summary of the Invention

[0006] In view of this, embodiments of this application provide at least one control method for an exhaust gas recirculation (EGR) system and an EGR system.

[0007] The technical solution of this application embodiment is implemented as follows:

[0008] In one aspect, the embodiments of the present application provide a control method of an exhaust gas recirculation (EGR) system, the EGR system comprising a pre-stage exhaust pipe, a cooler, an EGR valve and a mixing valve; wherein the pre-stage exhaust pipe is connected to the cooler through a first pipeline, the cooler is connected to the EGR valve through a second pipeline, the EGR valve is connected to the mixing valve through a third pipeline, a rear oxygen sensor is arranged in the first pipeline, a temperature sensor is arranged in the second pipeline, a water pump is connected to the cooler through a fourth pipeline and a fifth pipeline to form a circulation pipeline of cooling medium, and the second pipeline and the third pipeline are connected to a differential pressure sensor through a sixth pipeline and a seventh pipeline, respectively; and the method comprises:

[0009] starting the EGR system;

[0010] obtaining a rear oxygen diagnostic value of the rear oxygen sensor, a temperature diagnostic value of the temperature sensor, and a differential pressure diagnostic value of the differential pressure sensor;

[0011] determining a leakage condition of at least one of the first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline and the seventh pipeline based on the rear oxygen diagnostic value, the temperature diagnostic value and the differential pressure diagnostic value.

[0012] In some implementations, the determining the leakage condition of at least one of the first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline and the seventh pipeline based on the rear oxygen diagnostic value, the temperature diagnostic value, the differential pressure diagnostic value and the pressure temperature comprises at least one of the following steps:

[0013] determining that the first pipeline leaks based on that the temperature diagnostic value is lower than a preset temperature range, the differential pressure diagnostic value is lower than a preset differential pressure range, and the rear oxygen diagnostic value is lower than a preset oxygen content range;

[0014] determining that at least one of the fourth pipeline and the fifth pipeline leaks based on that the temperature diagnostic value is higher than the preset temperature range;

[0015] determining that at least one of the sixth pipeline and the seventh pipeline leaks based on that the temperature diagnostic value is within the preset temperature range, the rear oxygen diagnostic value is within the preset oxygen content range, and the differential pressure diagnostic value is lower than the preset differential pressure range.

[0016] In some implementations, the EGR system further comprises a supercharger and a throttle valve; wherein the mixing valve is connected to fresh air through an eighth pipeline, the mixing valve is connected to the supercharger through a ninth pipeline, the EGR valve is connected to the ninth pipeline through the third pipeline, the supercharger is connected to the throttle valve through a tenth pipeline, and a pressure temperature sensor is arranged in the tenth pipeline;

[0017] The method further comprises:

[0018] obtaining a pressure temperature diagnostic value of the pressure temperature sensor;

[0019] determining a leakage condition of at least one of the second pipeline, the third pipeline, the eighth pipeline, the ninth pipeline and the tenth pipeline based on the post-oxygen diagnostic value, the temperature diagnostic value, the pressure difference diagnostic value and the pressure temperature diagnostic value.

[0020] In some implementations, the determining the leakage condition of the second pipeline, the third pipeline, the eighth pipeline, the ninth pipeline and the tenth pipeline based on the post-oxygen diagnostic value, the temperature diagnostic value, the pressure difference diagnostic value and the pressure temperature diagnostic value comprises at least one of the following steps:

[0021] determining that the second pipeline leaks based on that the temperature diagnostic value is lower than a preset temperature range, the pressure difference diagnostic value is lower than a preset pressure difference range and the pressure temperature diagnostic value is lower than a preset pressure temperature range;

[0022] determining that the third pipeline leaks based on that the temperature diagnostic value is within the preset temperature range, the pressure difference diagnostic value is lower than the preset pressure difference range and the pressure temperature diagnostic value is lower than the preset pressure temperature range;

[0023] determining that the ninth pipeline leaks based on that the temperature diagnostic value is within the preset temperature range, the pressure difference diagnostic value is within the preset pressure difference range and the pressure temperature diagnostic value is lower than the preset pressure temperature range.

[0024] In some implementations, the method further comprises:

[0025] determining an opening value of the mixing valve, an adjustment position of the supercharger and a noise value;

[0026] determining that the eighth pipeline leaks based on that the opening value of the mixing valve is different from a set opening value of the mixing valve and the noise value is greater than a preset threshold value, or the adjustment position of the supercharger is different from a set adjustment position of the supercharger and the noise value is greater than a preset threshold value.

[0027] In some implementations, the method further includes:

[0028] based on the temperature diagnostic value being higher than a preset temperature threshold and the fourth pipeline and the fifth pipeline being in a normal working state, performing a cooling operation for the EGR system.

[0029] In some implementations, the performing the cooling operation for the EGR system based on the temperature diagnostic value being higher than a preset temperature threshold and the fourth pipeline and the fifth pipeline being in a normal working state includes:

[0030] in a case where the temperature diagnostic value is greater than a first temperature threshold and less than a second temperature threshold and the fourth pipeline and the fifth pipeline are in a normal working state, controlling the water pump to operate at a first power; wherein the first temperature threshold is less than the second temperature threshold, and the first power is greater than a water pump power when the temperature diagnostic value is acquired.

[0031] In some implementations, the method further includes:

[0032] in a case where the water pump operates at the first power, acquiring a second temperature value of the temperature sensor;

[0033] if the second temperature value is within a preset temperature range, controlling the water pump to operate at the water pump power when the temperature diagnostic value is acquired;

[0034] if the second temperature value is greater than the second temperature threshold and less than a third temperature threshold, reducing an opening degree of the EGR valve and controlling the water pump to operate at a second power; wherein the third temperature threshold is greater than the second temperature threshold, and the second power is greater than the first power.

[0035] In some implementations, the method further includes:

[0036] in a case where the water pump operates at the second power, acquiring a third temperature value of the temperature sensor;

[0037] if the third temperature value is within the preset temperature range, controlling the water pump to operate at the water pump power when the temperature diagnostic value is acquired;

[0038] if the third temperature value is greater than or equal to the third temperature threshold, shutting down the EGR system.

[0039] In another aspect, an embodiment of the present application provides an exhaust gas recirculation (EGR) system, which includes an electronic controller (ECU), a front exhaust pipe, a cooler, a water pump, an EGR valve, a mixing valve, an after oxygen sensor, a temperature sensor, and a differential pressure sensor; wherein

[0040] The pre-exhaust pipe is connected to the cooler through a first pipeline, and the rear oxygen sensor is arranged in the first pipeline;

[0041] The cooler is connected to the EGR valve through a second pipeline, and the temperature sensor is arranged in the second pipeline;

[0042] A water pump is connected to the cooler through a fourth pipeline and a fifth pipeline to form a circulating pipeline of cooling medium;

[0043] The EGR valve is connected to the mixing valve through a third pipeline;

[0044] The second pipeline and the third pipeline are connected to the differential pressure sensor through a sixth pipeline and a seventh pipeline respectively; wherein,

[0045] The ECU is configured to: start the EGR system; acquire a rear oxygen diagnostic value of the rear oxygen sensor, a temperature diagnostic value of the temperature sensor, and a differential pressure diagnostic value of the differential pressure sensor; and determine a leakage condition of at least one of the first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline, and the seventh pipeline based on the rear oxygen diagnostic value, the temperature diagnostic value, and the differential pressure diagnostic value.

[0046] In the embodiments of the present application, on the one hand, the leakage condition of the pipeline in the EGR system is determined by comprehensively analyzing the rear oxygen diagnostic value, the temperature diagnostic value, and the differential pressure diagnostic value collected by the rear oxygen sensor, the temperature sensor, and the differential pressure sensor. Since these sensors can reflect the rear oxygen, temperature, and pressure conditions of the EGR system in real time, the leakage point can be quickly identified, and the working reliability of the low-pressure EGR system is improved. On the other hand, in the control method for the abnormally high temperature of the EGR system, the abnormally high temperature is divided into multiple levels, and different processing schemes are provided for each level of high temperature, so that the use rate of the EGR system is maximized while the EGR system components are maximally protected.

[0047] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, but not limiting the technical solutions of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0048] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the technical solutions of the present application.

[0049] Figure 1 is a schematic diagram of the structure of an EGR system;

[0050] Figure 2A schematic diagram illustrating the implementation flow of a control method for an EGR system provided in this application embodiment;

[0051] Figure 3 This is a schematic diagram illustrating the implementation process of an application embodiment of the control method for abnormally high temperatures in an EGR system provided in this application.

[0052] Figure 4 This is a schematic diagram of the composition of a control device for an EGR system provided in an embodiment of this application. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application are further described in detail below with reference to the accompanying drawings and embodiments. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0055] The terms “first / second / third” are used merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that “first / second / third” may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used herein is for descriptive purposes only and is not intended to limit the scope of this application.

[0057] In related technologies, an EGR system has been proposed, which will be discussed below. Figure 1 The composition and structure of this EGR system are described in detail.

[0058] like Figure 1 As shown, the EGR system includes a front exhaust pipe 11, a rear exhaust pipe 13, a cooler 14, a water pump 15, an EGR valve 17, a mixing valve 19, a turbocharger 20, an intercooler 21, and a throttle valve 23.

[0059] Here, the pre-stage exhaust pipe 11 is connected to the cooler 14 through the first pipeline 1, so that the exhaust gas discharged from the pre-stage exhaust pipe 11 is sent to the cooler 14 through the first pipeline 1 for cooling, and then the cooled exhaust gas is sent to the ninth pipeline 9 through the EGR valve 17 for mixing with fresh air.

[0060] Meanwhile, the rear oxygen sensor 12 is arranged in the first pipeline 1. The rear oxygen sensor 12 is used to detect the oxygen concentration in the exhaust gas discharged from the pre-stage exhaust pipe 11, and feed back the oxygen concentration to the vehicle-mounted electronic control unit (ECU) in the form of voltage or current, so that the ECU can determine whether there is any abnormality such as pipeline leakage in the EGR system according to the oxygen concentration.

[0061] The cooler 14 is used to cool the exhaust gas. Since the exhaust gas discharged after the cylinder combustion has a high temperature, if the high-temperature exhaust gas is directly sent to the supercharger 20 through the EGR valve 17 for supercharging, the temperature of the EGR system components may be increased, which may cause damage to the pipeline or valve body, cause the EGR system to work abnormally, and even reduce the service life of the system components. Here, the cooling liquid driving device of the cooler 14 can be a water pump 15. The water pump 15 can be connected to both ends of the cooler 14 through the fourth pipeline 4 and the fifth pipeline 5 to form a circulating pipeline of the cooling medium, so that the cooling medium circulates and flows in the fourth pipeline 4, the internal pipeline of the cooler, and the fifth pipeline 5 under the driving force of the water pump 15, so as to achieve the effect of cooling the exhaust gas in the cooler 14. Here, the cooling liquid can be cooling water or other cooling medium.

[0062] The cooler 14 is connected to the EGR valve 17 through the second pipeline 2, so that the cooled exhaust gas is sent to the EGR valve 17, and then the amount of the exhaust gas entering the supercharger 20 is adjusted through the EGR valve 17. Meanwhile, the temperature sensor 16 is arranged in the second pipeline 2 to measure the temperature of the cooled exhaust gas.

[0063] Here, in order to detect the gas pressure at the inlet and outlet ends of the EGR valve 17, a differential pressure sensor is connected through pipelines at the inlet and outlet ends of the EGR valve 17; wherein the differential pressure sensor is connected to the second pipeline 2 through the sixth pipeline 6 and connected to the third pipeline 3 through the seventh pipeline 7, so as to measure the pressure and pressure difference of the gas at the inlet and outlet ends of the EGR valve 17.

[0064] The inlet end of the mixing valve 19 is connected to the outside fresh air through the eighth pipeline 8, so as to introduce fresh air into the EGR system; meanwhile, the outlet end of the mixing valve 19 is connected to the ninth pipeline 9, and the outlet end of the EGR valve 17 is connected to the ninth pipeline 9 through the third pipeline 3, so that the fresh air and the exhaust gas are mixed in the ninth pipeline 9 and then enter the supercharger 20.

[0065] The intake end of the turbocharger 20 is connected to the ninth pipeline 9 to receive the mixed gas and pressurize it.

[0066] The gas, pressurized by the turbocharger 20, is cooled again by the intercooler 21, and finally enters the cylinder for combustion through the throttle valve 23.

[0067] Here, the outlet of the intercooler 21 is connected to the intake of the throttle valve 23 via the tenth pipe 10, and a pressure and temperature sensor is installed in the tenth pipe 10 to detect the pressure and temperature of the gas mixture after being pressurized by the turbocharger 20 and cooled by the intercooler 21.

[0068] As can be seen from the above, in order to enable the engine to achieve a higher EGR rate (i.e., the ratio of the amount of recirculated exhaust gas to the total amount of intake air drawn into the cylinder), a temperature sensor and a differential pressure sensor are added to the EGR system to detect the temperature and pressure of each component in the EGR system. At the same time, the proportional, integral, and differential parameters of exhaust gas and fresh air, i.e., PID control, are used through the EGR valve and the mixing valve to achieve control of the EGR rate.

[0069] However, the above technical solutions only describe the structure and operation of the EGR system and do not propose diagnostic and control solutions for leaks in the EGR system's piping. Furthermore, in related technologies, when a temperature sensor detects abnormally high temperatures in the low-pressure EGR system, and these abnormally high temperatures persist for a specific duration, the EGR function is typically disabled directly to protect the EGR system's components and the engine. This results in overly stringent control and operating conditions for the EGR system under abnormally high temperatures, reducing the EGR system's control flexibility.

[0070] Based on this, embodiments of this application provide a control method for an exhaust gas recirculation (EGR) system. This method can be executed by an ECU or by a device with data processing capabilities, such as a server, laptop, tablet, desktop computer, or mobile device (e.g., mobile phone, personal digital assistant, dedicated messaging device), through remote control.

[0071] Below, we will combine Figure 1 The EGR system shown Figure 2 The schematic diagram illustrating the implementation flow of the EGR system control method in this application demonstrates the control method of the EGR system provided in this embodiment. The specific structure of the EGR system is described above. It should be noted that the EGR system involved in this embodiment can also be... Figure 1 The EGR system shown may contain different components or have different connection methods. For example...Figure 2 As shown, the method comprises the following steps S201 to S203:

[0072] Step S201, starting the EGR system;

[0073] Here, the EGR system can be started by the ECU issuing a start command, or by a server, a notebook computer or other device through remote control. The control method proposed in the embodiments of the application will be described below with the ECU as the control subject.

[0074] Step S202, obtaining the post-oxygen diagnostic value of the post-oxygen sensor, the temperature diagnostic value of the temperature sensor, and the differential pressure diagnostic value of the differential pressure sensor;

[0075] Here, after the EGR system is started, the post-oxygen sensor 12 will obtain the oxygen concentration in the exhaust gas discharged from the pre-stage exhaust pipe 11, and take the oxygen concentration as the post-oxygen diagnostic value, which will be transmitted to the ECU in the form of a voltage signal or a current signal; the temperature sensor 16 will detect the temperature of the exhaust gas after being cooled by the cooler 14, and transmit the temperature to the ECU as the temperature diagnostic value; the differential pressure sensor 18 will detect the exhaust gas pressure at the inlet and outlet of the EGR valve 17, and transmit the exhaust gas pressure to the ECU as the differential pressure diagnostic value.

[0076] Step S203, determining the leakage condition of at least one of the first pipe, the second pipe, the third pipe, the fourth pipe, the fifth pipe, the sixth pipe and the seventh pipe based on the post-oxygen diagnostic value, the temperature diagnostic value and the differential pressure diagnostic value.

[0077] Here, the ECU analyzes the received post-oxygen diagnostic value, temperature diagnostic value and differential pressure diagnostic value, and determines the leakage condition of the pipes in the EGR system according to the analysis result.

[0078] As can be seen from the above, in the control method of the EGR system provided in the embodiments of the application, the post-oxygen diagnostic value, the temperature diagnostic value and the differential pressure diagnostic value collected by the post-oxygen sensor, the temperature sensor and the differential pressure sensor are comprehensively analyzed to determine the leakage condition of the pipes in the EGR system. Since these sensors can reflect the post-oxygen, temperature and pressure conditions of the EGR system in real time, the leakage point can be quickly identified, and the working reliability of the low-pressure EGR system is improved.

[0079] In some implementations, the above step S203 can be implemented by at least one of the following steps S2031, S2032 and S2033:

[0080] Step S2031, based on the temperature diagnostic value being lower than the preset temperature range, the pressure difference diagnostic value being lower than the preset pressure difference range, and the post-oxygen diagnostic value being lower than the preset oxygen content range, it is determined that the first pipeline has a leak;

[0081] Here, the exhaust gas in the current stage exhaust pipe 11 enters the cooler 14 through the first pipeline, and due to the high temperature of the exhaust gas, even after cooling by the cooler 14, the temperature of the exhaust gas will still be maintained above the ambient temperature. When the first pipeline has a leak, the exhaust gas in the front stage exhaust pipe 11 cannot enter the cooler 14 through the first pipeline, resulting in the temperature diagnostic value detected by the temperature sensor arranged in the second pipeline 2 fluctuating around the ambient temperature. In some implementations, the preset temperature range is a range in which the minimum temperature is greater than the ambient temperature.

[0082] At the same time, when the first pipeline has a leak, since no exhaust gas enters the second pipeline 2 and the EGR valve 17 through the cooler 14, no exhaust gas flows into the intake end and the exhaust end of the EGR valve 17, so no exhaust gas flows in the sixth pipeline 6 and the seventh pipeline 7, and the pressure values in the sixth pipeline 6 and the seventh pipeline 7 detected by the pressure difference sensor 18 fluctuate around the atmospheric pressure value. In some implementations, the preset pressure difference range is a range in which the minimum pressure value is the atmospheric pressure value.

[0083] In addition, when the first pipeline 1 has a leak, the exhaust gas discharged from the front stage exhaust pipe 11 is not recycled by the EGR system, resulting in a decrease in the oxygen content in the exhaust gas discharged from the front stage exhaust pipe 11, i.e., the post-oxygen diagnostic value is lower than the preset oxygen content range.

[0084] In this way, when the diagnostic values of the sensors related to the leak of the first pipeline 1 are simultaneously abnormal, the leak of the first pipeline 1 can be quickly located.

[0085] Step S2032, based on the temperature diagnostic value being higher than the preset temperature range, it is determined that at least one of the fourth pipeline and the fifth pipeline has a leak;

[0086] Here, when at least one of the fourth pipeline 4 and the fifth pipeline 5 has a leak, the coolant driven by the water pump 15 cannot circulate in the fourth pipeline 4 and the fifth pipeline 5, resulting in the exhaust gas in the cooler 14 not being effectively cooled, and the exhaust gas entering the second pipeline 2 is still high-temperature exhaust gas. Therefore, the temperature diagnostic value detected by the temperature sensor 16 in the second pipeline 2 is high. In this way, by judging that the temperature diagnostic value is higher than the preset temperature range, it can be determined that at least one of the fourth pipeline 4 and the fifth pipeline 5 has a leak.

[0087] In actual applications, the preset temperature range can be set according to actual working conditions. For example, the minimum value of the preset temperature range can be set as a temperature value greater than the ambient temperature, and the maximum value can be set as a temperature value that will cause serious wear of the components of the EGR system (for example, 175°C).

[0088] In step S2033, based on the temperature diagnostic value being within the preset temperature range, the pressure difference diagnostic value being lower than the preset pressure difference range, and the post-oxygen diagnostic value being within the preset oxygen content range, it is determined that at least one of the sixth pipeline and the seventh pipeline is leaking.

[0089] Here, when the temperature diagnostic value is within the preset temperature range and the post-oxygen diagnostic value is within the preset oxygen content range, it indicates that the first pipeline, the second pipeline, the fourth pipeline, and the fifth pipeline are all in a normal working state. When the pressure difference diagnostic value is lower than the preset pressure difference range, it indicates that at least one of the sixth pipeline 6 and the seventh pipeline 7 is leaking. Specifically, when the pressure difference diagnostic value indicates that the pressure in the sixth pipeline 6 is floating around the atmospheric pressure value, it indicates that the sixth pipeline 6 is leaking. When the pressure difference diagnostic value indicates that the pressure in the seventh pipeline 7 is floating around the atmospheric pressure value, it indicates that the seventh pipeline 7 is leaking.

[0090] In this way, by comprehensively analyzing the post-oxygen diagnostic value, the temperature diagnostic value, and the pressure difference diagnostic value detected by the post-oxygen sensor 12, the temperature sensor 16, and the pressure difference sensor 18, the leakage conditions of the first pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline, and the seventh pipeline can be obtained, and the rapid diagnosis of the leakage condition of the EGR system pipeline can be realized.

[0091] In some implementations, the above step S203 can further include steps S2034 to S2035:

[0092] In step S2034, a pressure temperature diagnostic value of the pressure temperature sensor is obtained.

[0093] Here, the pressure temperature sensor is used to measure the pressure value and the temperature value of the mixed gas after being pressurized and cooled.

[0094] In step S2035, based on the post-oxygen diagnostic value, the temperature diagnostic value, the pressure difference diagnostic value, and the pressure temperature diagnostic value, the leakage condition of at least one of the second pipeline, the third pipeline, the eighth pipeline, the ninth pipeline, and the tenth pipeline is determined.

[0095] In this way, by adding the analysis of the diagnostic values of the pressure and temperature in the tenth pipeline 10, the leakage conditions of the second pipeline, the third pipeline, the eighth pipeline, the ninth pipeline, and the tenth pipeline can be further located.

[0096] In some implementations, the step S2035 can be implemented by at least one of the following steps S2036, S2037 and S2038:

[0097] In the step S2036, it is determined that the second pipeline has a leakage based on that the temperature diagnostic value is lower than the preset temperature range, the pressure difference diagnostic value is lower than the preset pressure difference range, and the pressure temperature diagnostic value is lower than the preset pressure temperature range.

[0098] Here, when the second pipeline 2 has a leakage, the exhaust gas discharged through the front-stage exhaust pipe 11 leaks in the second pipeline 2, resulting in that the temperature value detected by the temperature sensor 16 in the second pipeline 2 is the ambient temperature, i.e., the temperature diagnostic value detected by the temperature sensor is less than the preset temperature range.

[0099] Meanwhile, when the second pipeline 2 has a leakage, the exhaust gas cannot enter the EGR valve 17 through the second pipeline 2, resulting in that there is no exhaust gas flowing in the intake end and the exhaust end of the EGR valve 17, i.e., the pressure values in the sixth pipeline 6 and the seventh pipeline 7 detected by the pressure difference sensor are both floating around the atmospheric pressure value, i.e., the pressure difference diagnostic value is lower than the preset pressure difference range.

[0100] In addition, since the exhaust gas cannot enter the supercharger 20 through the EGR valve 17 and the ninth pipeline 9, the amount of gas in the supercharger 20 is reduced, so that the pressure and the temperature of the mixed gas pressurized by the supercharger 20 are reduced, thereby resulting in that the pressure temperature diagnostic value detected by the pressure temperature sensor is lower than the preset pressure temperature range.

[0101] In this way, by comprehensively analyzing the diagnostic values of the temperature sensor 16, the pressure difference sensor 18 and the pressure temperature sensor 22 related to the second pipeline 2, the leakage of the second pipeline 2 can be located.

[0102] In the step S2037, it is determined that the third pipeline has a leakage based on that the temperature diagnostic value is within the preset temperature range, the pressure difference diagnostic value is lower than the preset pressure difference range, and the pressure temperature diagnostic value is lower than the preset pressure temperature range.

[0103] When the temperature diagnostic value detected by the temperature sensor 16 is within the preset temperature range, it indicates that the exhaust gas discharged through the front-stage exhaust pipe 11 can normally enter the EGR valve 17 through the first pipeline 1 and the second pipeline 2, and the fourth pipeline 4 and the fifth pipeline 5 are in a normal working state.

[0104] Since the third pipeline has a leakage, the gas pressure at the output end of the EGR valve 17 is atmospheric pressure, and the pressure value in the seventh pipeline 7 detected by the pressure difference sensor 18 is floating around the atmospheric pressure, i.e., the pressure difference diagnostic value is lower than the preset pressure difference range.

[0105] Meanwhile, since the third pipeline leaks, the exhaust gas cannot enter the supercharger 20, so that the pressure and temperature of the mixed gas after being pressurized by the supercharger 20 decrease, thereby causing the pressure and temperature diagnostic value detected by the pressure and temperature sensor to be lower than the preset pressure and temperature range.

[0106] In this way, by comprehensively analyzing the diagnostic values of the temperature sensor 16, the differential pressure sensor 18, and the pressure and temperature sensor 22 related to the third pipeline 3, the leakage of the third pipeline 3 can be located.

[0107] In step S2038, it is determined that the ninth pipeline leaks based on that the temperature diagnostic value is within the preset temperature range, the differential pressure diagnostic value is within the preset differential pressure range, and the pressure and temperature diagnostic value is lower than the pressure and temperature range.

[0108] The temperature diagnostic value detected by the temperature sensor 16 within the preset temperature range indicates that the exhaust gas discharged by the front exhaust pipe 11 can normally enter the EGR valve 17 through the first pipeline 1 and the second pipeline 2, and the fourth pipeline 4 and the fifth pipeline 5 are in a normal working state.

[0109] The differential pressure diagnostic value of the differential pressure sensor 18 within the preset differential pressure range indicates that the sixth pipeline 6, the seventh pipeline 7, and the third pipeline 3 are in a normal working state.

[0110] When the ninth pipeline 9 leaks, the mixed gas cannot normally enter the supercharger 20, that is, the amount of mixed gas entering the supercharger 20 is only a part of the amount of gas required when the supercharger is normally working, thereby causing the pressure and temperature diagnostic value detected by the pressure and temperature sensor 22 to be lower than the preset pressure and temperature range.

[0111] In this way, by comprehensively analyzing the diagnostic values of the temperature sensor 16, the differential pressure sensor 18, and the pressure and temperature sensor 22 related to the ninth pipeline 9, the leakage of the ninth pipeline 9 can be located.

[0112] Based on the above steps S2036 to S2038, the abnormal conditions diagnosed by the temperature sensor 16, the differential pressure sensor 18, and the pressure and temperature sensor 22 can be comprehensively analyzed, and different pipeline leakage positions can be determined, thereby achieving accurate maintenance of the EGR system.

[0113] In some implementations, the control method of the EGR system provided by the embodiments of the present application further includes the following steps S204 to S205:

[0114] In step S204, the opening value of the mixing valve, the adjustment position of the supercharger, and the noise value are determined.

[0115] Here, the ECU can send a control signal to the mixture valve to adjust the opening value of the mixture valve, and can identify the opening value signal of the mixture valve to determine whether the mixture valve is stuck.

[0116] Similarly, the ECU can send a control signal to the supercharger to control the adjustment position of the supercharger, and can identify the adjustment position signal of the supercharger to determine whether the adjustment position of the supercharger is abnormal.

[0117] The noise value can be a noise, vibration, and harshness (NVH) value generated due to the pipeline abnormality.

[0118] Step S205, based on the opening value of the mixture valve being different from the set opening value of the mixture valve and the noise value being greater than the preset threshold value, or the adjustment position of the supercharger being different from the set adjustment position of the supercharger and the noise value being greater than the preset threshold value, determining that the eighth pipeline leaks

[0119] Here, the air filter is arranged in the eighth pipeline to filter particulate matter in the air, so when the eighth pipeline leaks, the particulate matter in the fresh air directly enters the mixture valve, causing the mixture valve to be dirty and unable to accurately adjust the opening according to the control signal of the ECU; at the same time, due to the leakage of the eighth pipeline, the NVH value is increased. Therefore, when the opening value of the mixture valve is different from the set opening value of the mixture valve and the noise value is greater than the preset threshold value, it can be determined that the eighth pipeline leaks.

[0120] In addition, the particulate matter entering the supercharger through the mixture valve also causes the position adjustment device of the supercharger to be unable to accurately adjust the position of the supercharger according to the instruction of the ECU, so that the adjustment position signal of the supercharger received by the ECU is abnormal. Therefore, when the adjustment position of the supercharger is different from the set adjustment position of the supercharger and the noise value is greater than the preset threshold value, it can also be determined that the eighth pipeline leaks.

[0121] In some implementations, when the control method of the EGR system based on the embodiments of the present application determines that the EGR system has an abnormally high temperature, the present application also proposes a control method for the abnormally high temperature of the EGR system. Next, the control method for the abnormally high temperature of the EGR system proposed by the embodiments of the present application will be described in detail.

[0122] The control method for the abnormally high temperature of the EGR system proposed by the embodiments of the present application includes the following step S301.

[0123] Step S301, based on the temperature diagnosis value being higher than the preset temperature threshold value, and the fourth pipeline and the fifth pipeline being in a normal working state, performing a cooling operation for the EGR system.

[0124] When the temperature sensor 16 detects that the temperature of the exhaust gas cooled by the cooler 14 is higher than the preset temperature threshold, and it is determined that neither the fourth pipeline 4 nor the fifth pipeline 5 has a leakage, it indicates that the cooler 14 does not achieve the expected cooling effect. Since high-temperature exhaust gas can cause abnormal operation of the components of the EGR system, and even seriously damage the service life of the components, it is necessary to perform the cooling operation on the EGR system.

[0125] Through the above scheme, the abnormal high-temperature condition of the EGR system can be quickly determined, and the corresponding cooling operation can be taken for the abnormal high-temperature condition.

[0126] In some implementations, the step S301 can be implemented by the step S302:

[0127] Step S302, in the case that the temperature diagnosis value is greater than a preset first temperature threshold and less than a second temperature threshold, and the fourth pipeline and the fifth pipeline are in a normal working state, the water pump 15 is controlled to work at a first power; wherein the first temperature threshold is less than the second temperature threshold, and the first power is greater than the water pump power when the temperature diagnosis value is obtained.

[0128] Here, the first temperature threshold is the lowest temperature threshold for determining that the EGR system has an abnormal high temperature and needs to perform the cooling operation, for example, the first temperature threshold is T-2δ, wherein T is the highest temperature threshold for determining that the EGR system has an abnormal high temperature, and δ is a self-defined temperature change amount. The second temperature threshold is greater than the first temperature threshold, for example, the second temperature threshold is T-δ. In this way, when the temperature diagnosis value is greater than the first temperature threshold and less than the second temperature threshold, it indicates that the EGR system enters an abnormal high-temperature state, but the abnormal temperature is still within the temperature range that can be reduced by adjusting the power of the water pump 15 to reduce the temperature of the EGR system.

[0129] At this time, the ECU sends a control signal to the water pump 15 to control the water pump 15 to work at a first power; wherein the first power is greater than the water pump power when the temperature diagnosis value is obtained. In this way, by increasing the working power of the water pump 15, the circulation speed of the coolant in the cooler 14 can be accelerated, thereby improving the cooling efficiency of the exhaust gas, and achieving the effect of reducing the temperature of the exhaust gas and the components of the EGR system.

[0130] In some implementations, in the case that the water pump 15 works at the first power, the second temperature value detected by the temperature sensor 16 is continuously obtained, and the step S301 further includes the following steps S303 and S304:

[0131] Step S303, if the second temperature value is within the preset temperature range, control the water pump to work at the water pump power when the temperature diagnostic value is acquired;

[0132] If the second temperature value is within the preset temperature range, it indicates that the purpose of cooling the EGR system is achieved by adjusting the water pump 15 to the first power, and thereafter, the power of the water pump 15 can be adjusted to the water pump power when the temperature diagnostic value is acquired, so that the cooling system enters a normal cooling liquid circulation state.

[0133] Step S304, if the second temperature value is greater than the second temperature threshold and less than a preset third temperature threshold, reduce the opening of the EGR valve and control the water pump to work at a second power; wherein the third temperature threshold is greater than the second temperature threshold, and the second power is greater than the first power.

[0134] If the second temperature value is greater than the second temperature threshold and less than the third temperature threshold, wherein the third temperature threshold is greater than the second temperature threshold (for example, the third temperature value is T), it indicates that the purpose of cooling the EGR system is not achieved by adjusting the water pump 15 to the first power, and the second temperature value is still within the temperature range that can be reduced by adjusting the power of the water pump 15.

[0135] At this time, the ECU sends a control signal to the water pump 15 to make the water pump 15 work at the second power; wherein the second power is greater than the first power. In this way, by further increasing the power of the water pump 15, the circulation speed of the cooling liquid in the cooler 14 is accelerated, the cooling efficiency of the exhaust gas is improved, and the effect of reducing the temperature of the exhaust gas and the EGR system components is achieved. At the same time, the ECU sends a control signal to the EGR valve 17 to reduce the opening of the EGR valve 17, so as to reduce the amount of exhaust gas entering the EGR system, thereby reducing the total amount of temperature of the exhaust gas introduced into the EGR system.

[0136] In some implementations, in the case where the water pump 15 works at the second power, the third temperature value detected by the temperature sensor is continuously acquired, and the above step S301 further includes the following steps S305 and S306:

[0137] Step S305, if the third temperature value is within the preset temperature range, control the water pump to work at the water pump power when the temperature diagnostic value is acquired;

[0138] If the third temperature value is within the preset temperature range, it indicates that the purpose of cooling the EGR system is achieved by adjusting the water pump 15 to the second power, and at this time, the power of the water pump 15 can be adjusted to the water pump power when the temperature diagnostic value is acquired, so that the cooler system enters a normal cooling liquid circulation state.

[0139] Step S306, if the third temperature value is greater than or equal to the third temperature threshold, the EGR system is closed.

[0140] If the third temperature value is greater than or equal to the third temperature threshold, it means that the purpose of cooling the EGR system has not been achieved by adjusting the water pump 15 to the second power. At this time, since the third temperature threshold is the highest temperature threshold in the abnormally high temperature of the EGR system, in the case of greater than or equal to the third temperature threshold, the working abnormality of the components of the EGR system is prone to occur, and even the problem of seriously shortening the service life, therefore, the ECU closes the EGR system to protect the safety of the components of the EGR system.

[0141] From the above, it can be seen that the control method for the abnormally high temperature of the EGR system provided by the embodiments of the application can maximize the use of the EGR system while protecting the components of the EGR system to the maximum extent by dividing the abnormally high temperature into multiple levels and providing different processing schemes for each level of abnormally high temperature.

[0142] The application embodiments of the control method for the abnormally high temperature of the EGR system provided by the embodiments of the application will be described below with reference to the accompanying drawings. Figure 3 The application embodiments of the control method for the abnormally high temperature of the EGR system provided by the embodiments of the application will be described below with reference to the accompanying drawings.

[0143] As shown in the figure, the control method for the abnormally high temperature of the EGR system provided by the application embodiments includes the following steps: Figure 3

[0144] Step S401, obtaining a temperature diagnosis value detected by a temperature sensor; then executing step S402,

[0145] Step S402, determining whether the temperature diagnosis value is higher than T-2δ; if not, entering step S403, if yes, entering step S404,

[0146] Step S403, running the water pump according to the engine demand;

[0147] Here, when the temperature diagnosis value is lower than T-2δ, it proves that the current temperature of the EGR system is within the normal temperature range, and there is no abnormally high temperature. At this time, the water pump can be operated according to the engine demand.

[0148] Step S404, increasing the power of the water pump; then executing step S405,

[0149] Here, when the temperature diagnosis value is higher than T-2δ, it proves that the current temperature of the EGR system is high, and there is an abnormally high temperature. Therefore, the power of the water pump is increased to accelerate the cooling of the exhaust gas, thereby reducing the temperature of the EGR system.

[0150] ​Step S405, judging whether the temperature is higher than T-2δ; if not, going to step S403, if yes, going to step S406,

[0151] After the water pump power is increased, it is continuously judged whether the temperature is higher than T-2δ to determine whether the purpose of lowering the temperature of the EGR system is achieved by increasing the water pump power.

[0152] Step S406, judging whether the temperature is higher than T-δ; if not, executing step S404; if yes, executing step S407,

[0153] Here, the temperature sensor continuously detects the temperature of the exhaust gas cooled by the cooler, and when it is judged that the temperature of the cooled exhaust gas is higher than T-δ, step S407 is continuously executed; when it is judged that the temperature of the exhaust gas is not higher than T-δ, i.e. the temperature of the exhaust gas is between T-2δ and T-δ, step S404 is executed to increase the water pump power.

[0154] Step S407, reducing the EGR rate and continuously increasing the water pump power; then, executing step S408,

[0155] Here, the EGR rate is reduced, i.e. the amount of exhaust gas entering the EGR valve from the front exhaust pipe is reduced, so that the total heat of the exhaust gas entering the EGR system is reduced; the water pump power is continuously increased, which can further improve the cooling efficiency of the cooler on the exhaust gas.

[0156] Step S408, judging whether the temperature is higher than T-δ; if not, executing step S402; if yes, executing step S409,

[0157] Step S409, judging whether the temperature is equal to or higher than T; if not, executing step S402; if yes, executing step S410.

[0158] Here, when the temperature is equal to or higher than T, it is proved that the temperature of the EGR system has reached or exceeded the highest temperature threshold of the abnormally high temperature, at which the EGR system components will work abnormally, and even seriously shorten the service life, therefore, the EGR function is disabled to protect the EGR system components.

[0159] Based on the above-mentioned control method of the EGR system, the embodiments of the present application also provide an EGR system, wherein,

[0160] The EGR system comprises an electronic controller ECU, a front exhaust pipe, a cooler, a water pump, an EGR valve, a mixing valve, a rear oxygen sensor, a temperature sensor and a differential pressure sensor; wherein,

[0161] The front exhaust pipe is connected to the cooler through a first pipeline, and the rear oxygen sensor is arranged in the first pipeline;

[0162] The cooler is connected to the EGR valve through a second pipeline, and the temperature sensor is arranged in the second pipeline;

[0163] A water pump is connected to the cooler through a fourth pipeline and a fifth pipeline to form a circulation pipeline of cooling medium;

[0164] The EGR valve is connected to the mixing valve through a third pipeline;

[0165] The second pipeline and the third pipeline are connected to the differential pressure sensor through a sixth pipeline and a seventh pipeline respectively; wherein,

[0166] The ECU is configured to: start the EGR system; obtain a post-oxygen diagnostic value of the post-oxygen sensor, a temperature diagnostic value of the temperature sensor, and a differential pressure diagnostic value of the differential pressure sensor; and determine a leakage condition of at least one of the first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline, and the seventh pipeline based on the post-oxygen diagnostic value, the temperature diagnostic value, and the differential pressure diagnostic value.

[0167] In some implementations, the ECU is further configured to perform at least one of the following steps:

[0168] determine that the first pipeline leaks based on that the temperature diagnostic value is lower than a preset temperature range, the differential pressure diagnostic value is lower than a preset differential pressure range, and the post-oxygen diagnostic value is lower than a preset oxygen content range;

[0169] determine that at least one of the fourth pipeline and the fifth pipeline leaks based on that the temperature diagnostic value is higher than the preset temperature range;

[0170] determine that at least one of the sixth pipeline and the seventh pipeline leaks based on that the temperature diagnostic value is within the preset temperature range, the post-oxygen diagnostic value is within the preset oxygen content range, and the differential pressure diagnostic value is lower than a preset differential pressure range.

[0171] In some implementations, the EGR system further comprises a supercharger and a throttle valve; wherein the mixing valve is connected to fresh air through an eighth pipeline, the mixing valve is connected to the supercharger through a ninth pipeline, the EGR valve is connected to the ninth pipeline through the third pipeline, the supercharger is connected to the throttle valve through a tenth pipeline, and a pressure temperature sensor is arranged in the tenth pipeline; and the ECU is further configured to:

[0172] obtain a pressure temperature diagnostic value of the pressure temperature sensor;

[0173] determine a leakage of at least one of the second pipeline, the third pipeline, the eighth pipeline, the ninth pipeline and the tenth pipeline based on the post-oxygen diagnosis value, the temperature diagnosis value, the pressure difference diagnosis value and the pressure temperature diagnosis value.

[0174] In some implementations, the ECU is further configured to perform at least one of the following steps:

[0175] determine a leakage of the second pipeline based on that the temperature diagnosis value is lower than a preset temperature range, the pressure difference diagnosis value is lower than a preset pressure difference range and the pressure temperature diagnosis value is lower than a preset pressure temperature range;

[0176] determine a leakage of the third pipeline based on that the temperature diagnosis value is within the preset temperature range, the pressure difference diagnosis value is lower than the preset pressure difference range and the pressure temperature diagnosis value is lower than the preset pressure temperature range;

[0177] determine a leakage of the ninth pipeline based on that the temperature diagnosis value is within the preset temperature range, the pressure difference diagnosis value is within the preset pressure difference range and the pressure temperature diagnosis value is lower than the preset pressure temperature range.

[0178] In some implementations, the ECU is further configured to:

[0179] determine an opening value of the mixing valve, an adjustment position of the supercharger and a noise value;

[0180] determine a leakage of the eighth pipeline based on that the opening value of the mixing valve is different from a set opening value of the mixing valve and the noise value is greater than a preset threshold value, or the adjustment position of the supercharger is different from a set adjustment position of the supercharger and the noise value is greater than the preset threshold value.

[0181] In some implementations, the ECU is further configured to:

[0182] perform a cooling operation for the EGR system based on that the temperature diagnosis value is higher than a preset temperature threshold value and the fourth pipeline and the fifth pipeline are in a normal working state.

[0183] In some implementations, the ECU is further configured to:

[0184] control the water pump to work at a first power in a case that the temperature diagnosis value is greater than a first temperature threshold value and less than a second temperature threshold value and the fourth pipeline and the fifth pipeline are in the normal working state, wherein the first temperature threshold value is less than the second temperature threshold value, and the first power is greater than a water pump power when the temperature diagnosis value is acquired.

[0185] In some implementations, the ECU is further configured to:

[0186] acquire a second temperature value of the temperature sensor when the water pump operates at the first power;

[0187] if the second temperature value is within a preset temperature range, control the water pump to operate at the water pump power at which the temperature diagnostic value is acquired;

[0188] if the second temperature value is greater than the second temperature threshold and less than a preset third temperature threshold, reduce the opening degree of the EGR valve and control the water pump to operate at a second power; wherein the third temperature threshold is greater than the second temperature threshold, and the second power is greater than the first power.

[0189] In some implementations, the ECU is further configured to:

[0190] acquire a third temperature value of the temperature sensor when the water pump operates at the second power;

[0191] if the third temperature value is within the preset temperature range, control the water pump to operate at the water pump power at which the temperature diagnostic value is acquired;

[0192] if the third temperature value is greater than or equal to the third temperature threshold, turn off the EGR system.

[0193] Based on the foregoing embodiments, the embodiments of the present application provide a control device of an EGR system, which includes various units and modules included in the units, and can be implemented by a processor in a computer device. Of course, it can also be implemented by a specific logic circuit. In the implementation process, the processor can be a central processing unit (CPU), a micro processing unit (MPU), a digital signal processor (DSP), or a field programmable gate array (FPGA).

[0194] Figure 4 A component structure diagram of the control device of the EGR system provided by the embodiments of the present application is shown in FIG. 5. Figure 4 As shown in FIG. 5, the control device 500 of the EGR system includes a starting module 501, an acquisition module 502, and a determination module 503, wherein:

[0195] The starting module 501 is configured to start the EGR system.

[0196] The acquisition module 502 is configured to acquire a post-oxygen diagnostic value of the post-oxygen sensor, a temperature diagnostic value of the temperature sensor, and a differential pressure diagnostic value of the differential pressure sensor.

[0197] The determination module 503 is configured to determine a leakage condition of at least one of the first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline, and the seventh pipeline based on the post-oxygen diagnostic value, the temperature diagnostic value, and the differential pressure diagnostic value.

[0198] In some implementations, the determination module 503 is further configured to perform at least one of the following steps:

[0199] determine that the first pipeline leaks based on that the temperature diagnostic value is lower than a preset temperature range, the differential pressure diagnostic value is lower than a preset differential pressure range, and the post-oxygen diagnostic value is lower than a preset oxygen content range;

[0200] determine that at least one of the fourth pipeline and the fifth pipeline leaks based on that the temperature diagnostic value is higher than the preset temperature range;

[0201] determine that at least one of the sixth pipeline and the seventh pipeline leaks based on that the temperature diagnostic value is within the preset temperature range, the post-oxygen diagnostic value is within the preset oxygen content range, and the differential pressure diagnostic value is lower than a preset differential pressure range.

[0202] In some implementations, the EGR system further comprises a supercharger and a throttle valve; wherein the mixing valve is connected to fresh air through an eighth pipeline, the mixing valve is connected to the supercharger through a ninth pipeline, the EGR valve is connected to the ninth pipeline through the third pipeline, the supercharger is connected to the throttle valve through a tenth pipeline, and a pressure temperature sensor is arranged in the tenth pipeline;

[0203] The determination module 503 is further configured to:

[0204] acquire a pressure temperature diagnostic value of the pressure temperature sensor;

[0205] determine a leakage condition of at least one of the second pipeline, the third pipeline, the eighth pipeline, the ninth pipeline, and the tenth pipeline based on the post-oxygen diagnostic value, the temperature diagnostic value, the differential pressure diagnostic value, and the pressure temperature diagnostic value.

[0206] In some implementations, the determination module 503 is further configured to perform at least one of the following steps:

[0207] determining that the second pipeline has a leakage based on the temperature diagnosis value being lower than a preset temperature range, the pressure difference diagnosis value being lower than a preset pressure difference range, and the pressure temperature diagnosis value being lower than a preset pressure temperature range;

[0208] determining that the third pipeline has a leakage based on the temperature diagnosis value being within the preset temperature range, the pressure difference diagnosis value being lower than the preset pressure difference range, and the pressure temperature diagnosis value being lower than the preset pressure temperature range;

[0209] determining that the ninth pipeline has a leakage based on the temperature diagnosis value being within the preset temperature range, the pressure difference diagnosis value being within the preset pressure difference range, and the pressure temperature diagnosis value being lower than the preset pressure temperature range.

[0210] In some implementations, the determining module 503 is further configured to:

[0211] determining an opening value of the mixing valve, an adjustment position of the supercharger, and a noise value;

[0212] determining that the eighth pipeline has a leakage based on the opening value of the mixing valve being different from a set opening value of the mixing valve and the noise value being greater than a preset threshold, or the adjustment position of the supercharger being different from a set adjustment position of the supercharger and the noise value being greater than the preset threshold.

[0213] In some implementations, the determining module 503 is further configured to:

[0214] performing a cooling operation for the EGR system based on the temperature diagnosis value being higher than a preset temperature threshold and the fourth pipeline and the fifth pipeline being in a normal working state.

[0215] In some implementations, the determining module 503 is further configured to:

[0216] controlling the water pump to work at a first power when the temperature diagnosis value is greater than a first temperature threshold and less than a second temperature threshold, and the fourth pipeline and the fifth pipeline are in the normal working state, wherein the first temperature threshold is less than the second temperature threshold, and the first power is greater than a water pump power when the temperature diagnosis value is acquired.

[0217] In some implementations, the determining module 503 is further configured to:

[0218] acquiring a second temperature value of the temperature sensor when the water pump works at the first power;

[0219] controlling the water pump to work at the water pump power when the temperature diagnosis value is acquired if the second temperature value is within a preset temperature range.

[0220] if the second temperature value is greater than the second temperature threshold and less than a preset third temperature threshold, reducing the opening degree of the EGR valve and controlling the water pump to operate at a second power; wherein the third temperature threshold is greater than the second temperature threshold, and the second power is greater than the first power.

[0221] In some implementations, the determining module 503 is further configured to:

[0222] In the case that the water pump operates at the second power, obtaining a third temperature value of the temperature sensor;

[0223] if the third temperature value is within the preset temperature range, controlling the water pump to operate at the water pump power when the temperature diagnosis value is obtained;

[0224] if the third temperature value is greater than or equal to the third temperature threshold, closing the EGR system.

[0225] The above device embodiments are similar to the above method embodiments in description, and have similar beneficial effects to the method embodiments. In some embodiments, the device provided by the embodiments of the present application has the functions or includes the modules for executing the methods described in the above method embodiments. For technical details not disclosed in the device embodiments of the present application, please refer to the description of the method embodiments of the present application.

[0226] It should be understood that the "one embodiment" or "an embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily mean the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in various embodiments of the present application, the size of the sequence number of each step / process does not mean the execution order, and the execution order of each step / process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application. The above sequence number of the embodiments of the present application is only for description, not representing the advantages and disadvantages of the embodiments.

[0227] It should be noted that, in the present document, the terms "comprising", "containing", or any other similar term are intended to encompass non-exclusive inclusion, such that processes, methods, articles, or apparatuses that comprise a list of elements are not limited to those elements, but can also include other elements not expressly listed, or also include elements inherent in such processes, methods, articles, or apparatuses. Without further limitation, an element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0228] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed components can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0229] The units described above as separate components can or can not be physically separated, and the components shown as units can or can not be physical units; they can be located in one place or distributed on multiple network units; and part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0230] In addition, each functional unit in each embodiment of the present application can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be realized in the form of hardware or in the form of hardware plus software functional unit.

[0231] Those of ordinary skill in the art can understand that all or part of the steps of the above method embodiments can be completed by program instruction related hardware, and the foregoing program can be stored in a computer readable storage medium, and the program executes the steps of the above method embodiments when executed; and the foregoing storage medium includes: mobile storage device, read only memory (Read Only Memory, ROM), magnetic disc or optical disc, and various storage program codes.

[0232] Alternatively, the above-mentioned integrated units of the present application, if realized in the form of software function modules and sold or used as independent products, can also be stored in a computer-readable storage medium. Based on such understanding, the technical solutions of the present application or the parts that make contributions to the related art can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the methods described in the various embodiments of the present application. The aforementioned storage medium includes mobile storage devices, ROM, magnetic discs or optical discs, and various media that can store program codes.

[0233] The above merely describes the embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application.

Claims

1. A control method of an exhaust gas recirculation (EGR) system, the EGR system including a pre-exhaust pipe, a cooler, an EGR valve, and a mixing valve; wherein, The front-stage exhaust pipe is connected to the cooler through a first pipeline, the cooler is connected to the EGR valve through a second pipeline, the EGR valve is connected to the mixing valve through a third pipeline, a rear oxygen sensor is arranged in the first pipeline, a temperature sensor is arranged in the second pipeline, a water pump is connected to the cooler through a fourth pipeline and a fifth pipeline to form a circulating pipeline of cooling medium, and the second pipeline and the third pipeline are connected to a differential pressure sensor through a sixth pipeline and a seventh pipeline respectively; and the method comprises: starting the EGR system; obtaining a rear oxygen diagnosis value of the rear oxygen sensor, a temperature diagnosis value of the temperature sensor, and a differential pressure diagnosis value of the differential pressure sensor; determining that the first pipeline leaks based on the temperature diagnosis value being lower than a preset temperature range, the differential pressure diagnosis value being lower than a preset differential pressure range, and the rear oxygen diagnosis value being lower than a preset oxygen content range, or determining that at least one of the sixth pipeline and the seventh pipeline leaks based on the temperature diagnosis value being within the preset temperature range, the differential pressure diagnosis value being lower than the preset differential pressure range, and the rear oxygen diagnosis value being within the preset oxygen content range.

2. The method of claim 1, wherein, The method further comprises: determining that at least one of the fourth pipeline and the fifth pipeline leaks based on the temperature diagnosis value being higher than the preset temperature range.

3. The method of claim 1, wherein, The EGR system further comprises a supercharger and a throttle valve; wherein the mixing valve is connected to fresh air through an eighth pipeline, the mixing valve is connected to the supercharger through a ninth pipeline, the EGR valve is connected to the ninth pipeline through the third pipeline, the supercharger is connected to the throttle valve through a tenth pipeline, and a pressure temperature sensor is arranged in the tenth pipeline; The method further comprises: obtaining a pressure temperature diagnosis value of the pressure temperature sensor; and at least one of: determining that the second pipeline leaks based on the temperature diagnosis value being lower than a preset temperature range, the differential pressure diagnosis value being lower than a preset differential pressure range, and the pressure temperature diagnosis value being lower than a preset pressure temperature range; determining that the third pipeline leaks based on the temperature diagnosis value being within the preset temperature range, the differential pressure diagnosis value being lower than the preset differential pressure range, and the pressure temperature diagnosis value being lower than the preset pressure temperature range; determining that the ninth pipeline leaks based on the temperature diagnosis value being within the preset temperature range, the differential pressure diagnosis value being within the preset differential pressure range, and the pressure temperature diagnosis value being lower than the preset pressure temperature range.

4. The method of claim 3, wherein, The method further comprises: determining an opening value of the mixing valve, an adjustment position of the supercharger, and a noise value; determining that the eighth pipeline leaks based on the opening value of the mixing valve being different from a set opening value of the mixing valve and the noise value being greater than a preset threshold, or the adjustment position of the supercharger being different from a set adjustment position of the supercharger and the noise value being greater than a preset threshold.

5. The method of claim 1, wherein, The method further comprises: Based on the temperature diagnosis value being higher than a preset temperature threshold value and the fourth pipeline and the fifth pipeline being in a normal working state, a cooling operation for the EGR system is performed.

6. The method of claim 5, wherein, The cooling operation for the EGR system based on the temperature diagnosis value being higher than a preset temperature threshold value and the fourth pipeline and the fifth pipeline being in a normal working state comprises: In a case where the temperature diagnosis value is greater than a preset first temperature threshold value and less than a second temperature threshold value, and the fourth pipeline and the fifth pipeline are in a normal working state, the water pump is controlled to work at a first power; wherein the first temperature threshold value is less than the second temperature threshold value, and the first power is greater than a water pump power when the temperature diagnosis value is acquired.

7. The method of claim 6, wherein, Further comprising: In a case where the water pump works at the first power, a second temperature value of the temperature sensor is acquired; If the second temperature value is within a preset temperature range, the water pump is controlled to work at the water pump power when the temperature diagnosis value is acquired; If the second temperature value is greater than the second temperature threshold value and less than a preset third temperature threshold value, the opening degree of the EGR valve is reduced and the water pump is controlled to work at a second power; wherein the third temperature threshold value is greater than the second temperature threshold value, and the second power is greater than the first power.

8. The method of claim 7, wherein, Further comprising: In a case where the water pump works at the second power, a third temperature value of the temperature sensor is acquired; If the third temperature value is within the preset temperature range, the water pump is controlled to work at the water pump power when the temperature diagnosis value is acquired; If the third temperature value is greater than or equal to the third temperature threshold value, the EGR system is closed.

9. An exhaust gas recirculation (EGR) system, comprising: The EGR system comprises an electronic controller (ECU), a front exhaust pipe, a cooler, a water pump, an EGR valve, a mixing valve, an after oxygen sensor, a temperature sensor, and a differential pressure sensor; wherein The front exhaust pipe is connected to the cooler through a first pipeline, and the after oxygen sensor is arranged in the first pipeline; The cooler is connected to the EGR valve through a second pipeline, and the temperature sensor is arranged in the second pipeline; The water pump is connected to the cooler through a fourth pipeline and a fifth pipeline to form a circulation pipeline of cooling medium; The EGR valve is connected to the mixing valve through a third pipeline; The second pipeline and the third pipeline are respectively connected to the differential pressure sensor through a sixth pipeline and a seventh pipeline; wherein The ECU is configured to: start the EGR system; acquire a post-oxygen diagnostic value of the post-oxygen sensor, a temperature diagnostic value of the temperature sensor, and a differential pressure diagnostic value of the differential pressure sensor; determine that a leak occurs in the first pipeline based on that the temperature diagnostic value is lower than a preset temperature range, the differential pressure diagnostic value is lower than a preset differential pressure range, and the post-oxygen diagnostic value is lower than a preset oxygen content range; or determine that at least one of the sixth pipeline and the seventh pipeline has a leak based on that the temperature diagnostic value is within the preset temperature range, the differential pressure diagnostic value is lower than a preset differential pressure range, and the post-oxygen diagnostic value is within the preset oxygen content range.

Images