A method and device for detecting carbon deposition in an exhaust gas recirculation system and a vehicle

Abstract

The embodiment of the present application discloses a method, device and vehicle for detecting carbon deposition in an exhaust gas recirculation system. Based on the execution of the method for detecting carbon deposition in the exhaust gas recirculation system, the differential pressure growth rate of the DPF of the target vehicle is determined according to the current DPF differential pressure value and the initial DPF differential pressure value, and the temperature difference of the upstream of the DOC of the target vehicle is determined according to the current upstream temperature value of the DOC and the initial upstream temperature value of the DOC; based on the judgment that the differential pressure growth rate of the DPF meets the first condition and the temperature difference of the upstream of the DOC meets the second condition, it is prompted that the exhaust gas recirculation system EGR of the target vehicle has carbon deposition. It can be seen that in the embodiment of the present application, when judging whether the EGR system has carbon deposition, it is judged according to different driving conditions of the vehicle, and the differential pressure growth rate of the DPF of the target vehicle and the temperature difference of the upstream of the DOC of the target vehicle are considered at the same time, improving the accuracy of the carbon deposition detection of the EGR system.

Description

Technical Field

[0001] This application relates to the field of carbon deposit detection in an EGR system, and more specifically, to a method and device for detecting carbon deposits in an exhaust gas recirculation system and a vehicle. Background Art

[0002] The exhaust gas recirculation system (EGR) is one of the effective measures to reduce NOx emissions of diesel engines at present. The post-treatment system of diesel engines with the current national VI EGR route is highly sensitive to the intake system. If the intake air volume deviation is large, it will directly lead to inaccurate carbon deposit model values of the diesel particulate filter (DPF). If the actual intake air volume is small, it will increase the soot during combustion in the engine cylinder, accelerate carbon deposition, and cause DPF overload failure. It can be seen that the EGR system has a direct impact on the fresh air intake volume.

[0003] Due to carbon deposits in the venturi and EGR cooler, inaccurate measurement of EGR exhaust gas flow rate and large EGR flow resistance will cause the EGR valve to open too large. While the EGR exhaust gas flow rate increases, the fresh air intake volume decreases relatively, and the soot particles during combustion increase, resulting in an accelerated DPF carbon deposition rate, the actual carbon deposit value being greater than the model value, causing the DPF to report an overload failure and posing a risk of burning out the DPF carrier. Therefore, it is necessary to monitor the carbon deposits in the EGR system and clean them in a timely manner. However, the existing methods for detecting carbon deposits in the EGR system determine whether the EGR system has serious carbon deposits by the original exhaust NO x concentration and the temperature after EGR cooling, and timely remind the user to clean the carbon deposits in the venturi pipeline and the EGR cooler. The existing methods for detecting carbon deposits in the EGR system only judge the severity of carbon deposits in the EGR system from the condition of temperature, and there is a problem of low accuracy in judging EGR carbon deposit detection. Summary of the Invention

[0004] The purpose of this application is to provide a method and device for detecting carbon deposits in an exhaust gas recirculation system and a vehicle, based on which the carbon deposit detection method of the EGR system is executed to improve the accuracy of carbon deposit detection in the EGR system.

[0005] To achieve the above object, in the first aspect, this application provides a method for detecting carbon deposits in an exhaust gas recirculation system, the method comprising:

[0006] Obtain the current driving condition of the target vehicle;

[0007] Obtain the current pressure difference value of the diesel particulate filter DPF of the target vehicle and the initial DPF pressure difference value corresponding to the current driving condition; and determine the DPF pressure difference growth rate of the target vehicle according to the current DPF pressure difference value and the initial DPF pressure difference value;

[0008] Obtain the current upstream temperature value of the diesel oxidation catalyst (DOC) of the target vehicle and the initial upstream temperature value of the DOC corresponding to the current driving condition; and determine the upstream temperature difference of the DOC of the target vehicle according to the current DOC upstream temperature value and the initial DOC upstream temperature value.

[0009] Judge whether the DPF differential pressure growth rate meets the first condition; and judge whether the upstream temperature difference of the DOC meets the second condition.

[0010] If the DPF differential pressure growth rate meets the first condition and the upstream temperature difference of the DOC meets the second condition, then prompt that the exhaust gas recirculation (EGR) system of the target vehicle is carbonized.

[0011] Optionally, before obtaining the current differential pressure value of the diesel particulate filter (DPF) of the target vehicle and the initial DPF differential pressure value corresponding to the current driving condition; and determining the DPF differential pressure growth rate of the target vehicle according to the current DPF differential pressure value and the initial DPF differential pressure value, the method further includes:

[0012] Obtain the actual exhaust gas flow value of the EGR system and the set exhaust gas flow value of the EGR system corresponding to the current driving condition.

[0013] Determine the exhaust gas flow deviation value of the EGR system according to the actual exhaust gas flow value and the set exhaust gas flow value.

[0014] Judge whether the exhaust gas flow deviation value meets the third condition.

[0015] If the exhaust gas flow deviation value meets the third condition, then obtain the engine exhaust gas flow of the target vehicle.

[0016] Judge whether the engine exhaust gas flow of the target vehicle meets the fourth condition.

[0017] If the engine exhaust gas flow of the target vehicle meets the fourth condition, then execute obtaining the current DPF differential pressure value of the target vehicle and the initial DPF differential pressure value corresponding to the current driving condition.

[0018] Optionally, before obtaining the current upstream temperature value of the diesel oxidation catalyst (DOC) of the target vehicle and the initial upstream temperature value of the DOC corresponding to the current driving condition; and determining the upstream temperature difference of the DOC of the target vehicle according to the current DOC upstream temperature value and the initial DOC upstream temperature value, the method further includes:

[0019] Obtain the actual intake pressure value of the EGR system and the set intake pressure value of the EGR system corresponding to the current driving condition;

[0020] Determine the intake pressure deviation value of the EGR system according to the actual intake pressure value and the set intake pressure value;

[0021] Judge whether the intake pressure deviation value meets the fifth condition;

[0022] If the intake pressure deviation value meets the fifth condition, then execute obtaining the current DOC upstream temperature value of the target vehicle and the initial DOC upstream temperature value corresponding to the current driving condition.

[0023] Optionally, the determining the DPF differential pressure growth rate of the target vehicle according to the current DPF differential pressure value and the initial DPF differential pressure value specifically includes:

[0024] Obtain the total vehicle driving duration of the target vehicle after the vehicle leaves the factory;

[0025] According to the formula Determine the DPF differential pressure growth rate of the target vehicle; where ΔP is the DPF differential pressure growth rate, p1 is the current DPF differential pressure value, p2 is the initial DPF differential pressure value, and Δt is the total vehicle driving duration of the target vehicle after the vehicle leaves the factory.

[0026] Optionally, judging whether the DPF differential pressure growth rate meets the first condition specifically is:

[0027] Judge whether the DPF differential pressure growth rate is greater than or equal to 10%.

[0028] Optionally, the judging whether the DOC upstream temperature difference meets the second condition specifically includes:

[0029] Obtain a pre-stored DOC upstream temperature difference condition correspondence table; the DOC upstream temperature difference condition correspondence table includes the correspondence relationship between the engine speed and the DOC upstream temperature difference condition;

[0030] Obtain the current engine speed of the target vehicle;

[0031] According to the DOC upstream temperature difference condition correspondence table and the current engine speed, determine the second condition corresponding to the current engine speed;

[0032] Judge whether the DOC upstream temperature difference meets the second condition corresponding to the current engine speed.

[0033] In a second aspect, the present application also provides a carbon deposit detection device for an exhaust gas recirculation system, and the device includes:

[0034] An acquisition unit, configured to acquire the current driving condition of a target vehicle;

[0035] The acquisition unit is further configured to acquire the current differential pressure value of a diesel particulate filter (DPF) of the target vehicle, and an initial DPF differential pressure value corresponding to the current driving condition;

[0036] A calculation unit, configured to determine a DPF differential pressure growth rate of the target vehicle according to the current DPF differential pressure value and the initial DPF differential pressure value;

[0037] The acquisition unit is further configured to acquire the current upstream temperature value of a diesel oxidation catalyst (DOC) of the target vehicle, and an initial DOC upstream temperature value corresponding to the current driving condition;

[0038] The calculation unit is further configured to determine a DOC upstream temperature difference value of the target vehicle according to the current DOC upstream temperature value and the initial DOC upstream temperature value;

[0039] A judgment unit, configured to judge whether the DPF differential pressure growth rate meets a first condition; and judge whether the DOC upstream temperature difference value meets a second condition;

[0040] A processing unit, configured to, if the DPF differential pressure growth rate meets the first condition and the DOC upstream temperature difference value meets the second condition, prompt carbon deposition in an exhaust gas recirculation (EGR) system of the target vehicle.

[0041] Optionally, in the device:

[0042] The acquisition unit is further configured to acquire an actual exhaust gas flow value of the EGR system, and a set exhaust gas flow value of the EGR system corresponding to the current driving condition;

[0043] The calculation unit is further configured to determine an exhaust gas flow deviation value of the EGR system according to the actual exhaust gas flow value and the set exhaust gas flow value;

[0044] The judgment unit is further configured to judge whether the exhaust gas flow deviation value meets a third condition;

[0045] The acquisition unit is further configured to, if the exhaust gas flow deviation value meets the third condition, acquire the engine exhaust gas flow of the target vehicle;

[0046] The judgment unit is further configured to judge whether the engine exhaust gas flow of the target vehicle meets a fourth condition;

[0047] The obtaining unit is further configured to, if the engine exhaust gas flow rate of the target vehicle satisfies the fourth condition, obtain the current DPF pressure difference value of the target vehicle and the initial DPF pressure difference value corresponding to the current driving condition.

[0048] Optionally, in the device:

[0049] The obtaining unit is further configured to obtain the actual intake pressure value of the EGR system and the set intake pressure value of the EGR system corresponding to the current driving condition;

[0050] The calculating unit is further configured to determine the intake pressure deviation value of the EGR system according to the actual intake pressure value and the set intake pressure value;

[0051] The determining unit is further configured to determine whether the intake pressure deviation value satisfies the fifth condition;

[0052] The obtaining unit is further configured to, if the intake pressure deviation value satisfies the fifth condition, obtain the current DOC upstream temperature value of the target vehicle and the initial DOC upstream temperature value corresponding to the current driving condition.

[0053] In a third aspect, the present application further provides a vehicle, which uses the carbon deposit detection method for the exhaust gas recirculation system in any one of the first aspects to detect the carbon loading of the exhaust gas recirculation system.

[0054] In the embodiments of the present application, a carbon deposit detection method, device and vehicle for an exhaust gas recirculation system are provided. Based on performing the carbon deposit detection method for the exhaust gas recirculation system, the current driving condition of the target vehicle, the current DPF pressure difference value and the initial DPF pressure difference value corresponding to the current driving condition are obtained, the current DOC upstream temperature value and the initial DOC upstream temperature value corresponding to the current driving condition are obtained, the DPF pressure difference growth rate of the target vehicle is determined according to the current DPF pressure difference value and the initial DPF pressure difference value, and the DOC upstream temperature difference value of the target vehicle is determined according to the current DOC upstream temperature value and the initial DOC upstream temperature value; it is determined whether the DPF pressure difference growth rate satisfies the first condition, and it is determined whether the DOC upstream temperature difference value satisfies the second condition; if the DPF pressure difference growth rate satisfies the first condition and the DOC upstream temperature difference value satisfies the second condition, it is prompted that the exhaust gas recirculation system EGR of the target vehicle is carbon deposited. It can be seen that in the embodiments of the present application, when judging whether the EGR system is carbon deposited, the judgment is made for different driving conditions of the vehicle, and the DPF pressure difference growth rate of the target vehicle and the DOC upstream temperature difference value of the target vehicle are considered simultaneously, improving the accuracy of the carbon deposit detection of the EGR system. Description of the Drawings

[0055] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on the provided drawings.

[0056] Figure 1 It is a flowchart of a method for detecting carbon deposition in an exhaust gas recirculation system provided by an embodiment of the present application;

[0057] Figure 2 It is a flowchart of another method for detecting carbon deposition in an exhaust gas recirculation system provided by an embodiment of the present application;

[0058] Figure 3 It is a schematic diagram of a device for detecting carbon deposition in an exhaust gas recirculation system provided by an embodiment of the present application. Detailed implementation manners

[0059] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0060] First, the professional terms mentioned in the present application are explained:

[0061] Diesel after-treatment system: A system for treating diesel engine exhaust gas. The above-mentioned diesel after-treatment system should include a diesel oxidation catalyst converter, a diesel particulate filter, and a selective catalytic reduction converter.

[0062] Diesel oxidation catalyst converter (DOC), with an oxidation catalyst, mainly eliminates CO and HC in the exhaust gas and oxidizes NO to NO2.

[0063] Diesel particulate filter (DPF), mainly used to trap particulate matter in the exhaust gas.

[0064] Selective catalytic reduction converter (SCR), used to eliminate nitrogen oxides in the exhaust gas.

[0065] Exhaust Gas Recirculation (EGR) system: It is a system that introduces a part of the exhaust gas discharged after the combustion of the combustible mixture into the intake side and mixes it with the inhaled fresh air to make it participate in combustion again. Its function is to reduce the peak combustion temperature and pressure, thereby reducing the generation of NOx.

[0066] Due to the deposition of dry soot and carbureted hydrogens (HCs) contained in the exhaust gas on the surfaces such as the EGR cooler under the action of thermophoresis, static electricity, diffusion, and condensation to form carbon deposits. The carbon deposits reaching a stable state cause the intercooling heat transfer efficiency of the EGR to decrease by 20% - 30%, and the back pressure to reach twice that of the carbon deposit-free state. As a result, the emissions of NOx and PM from the engine and its economy become worse; the carbon deposits adhering to the Venturi pipeline cause the measured and calculated value of the EGR exhaust gas flow rate to be relatively small. To achieve a closed-loop of the EGR exhaust gas flow, the actual opening of the EGR valve will increase, resulting in an increase in the EGR exhaust gas flow rate and a decrease in the actual fresh air intake volume, leading to an increase in soot emissions.

[0067] It is found through experiments that after the EGR system has carbon deposits, it will cause the DPF to have carbon deposits too quickly and report a DPF overload fault. It is necessary to regularly clean pipelines such as the EGR cooler and Venturi. Due to different operating conditions of vehicles in the market, the carbon deposit rate of the EGR system is different, and the cleaning cycle of the EGR system for vehicles under different operating conditions is also different. The embodiment of this application designs a method for determining the carbon deposit degree of the EGR system based on the upstream temperature value of the DOC and the rising rate of the DPF differential pressure, detecting the carbon deposits of the EGR system, thereby determining whether cleaning is required, and then prompting the user to perform maintenance on the EGR system.

[0068] Regarding the existing method for detecting carbon deposits in the EGR system, which only judges the severity of carbon deposits in the EGR system from the condition of temperature, there is a problem of low accuracy in judging the detection of EGR carbon deposits. An exhaust gas recirculation system carbon deposit detection method, device, and vehicle provided in the embodiment of this application are based on implementing this exhaust gas recirculation system carbon deposit detection method, judging for different driving conditions of the vehicle, and simultaneously considering the DPF differential pressure growth rate of the target vehicle and the DOC upstream temperature difference of the target vehicle to improve the accuracy of EGR system carbon deposit detection.

[0069] Next, a detailed introduction will be given to an exhaust gas recirculation system carbon deposit detection method in this application:

[0070] Figure 1 It is a flowchart of an exhaust gas recirculation system carbon deposit detection method provided in the embodiment of this application. As Figure 1 shown, the embodiment of this application provides an exhaust gas recirculation system carbon deposit detection method, and the method includes:

[0071] S101: Obtain the current driving condition of the target vehicle;

[0072] It should be noted that the driving conditions of the vehicle include starting, accelerating, constant speed, decelerating, turning, uphill and downhill, parking and other driving conditions, which are not specifically limited here and can be determined according to the actual situation, and are all within the protection scope of this application.

[0073] S102: Obtain the current differential pressure value of the diesel particulate filter (DPF) of the target vehicle, and the initial DPF differential pressure value corresponding to the current driving condition; and determine the DPF differential pressure growth rate of the target vehicle according to the current DPF differential pressure value and the initial DPF differential pressure value;

[0074] It should be noted that the initial DPF differential pressure value corresponding to the current driving condition is obtained by querying the DPF differential pressure value table corresponding to the vehicle condition points in the universal data during bench development. The DPF differential pressure value table corresponding to the vehicle condition points in the universal data during bench development is generated during the bench development of the vehicle, and there is an initial DPF differential pressure value corresponding to each driving condition of the vehicle.

[0075] It should be noted that the DPF differential pressure growth rate can be determined according to the total driving duration of the vehicle after leaving the factory, the current DPF differential pressure value and the initial DPF differential pressure value of the target vehicle; it can also be determined according to the total driving mileage of the vehicle after leaving the factory, the current DPF differential pressure value and the initial DPF differential pressure value of the target vehicle.

[0076] Specifically, an explanation is given with the DPF differential pressure growth rate determined according to the total driving duration of the vehicle after leaving the factory, the current DPF differential pressure value and the initial DPF differential pressure value of the target vehicle:

[0077] Determining the DPF differential pressure growth rate of the target vehicle according to the current DPF differential pressure value and the initial DPF differential pressure value may include: obtaining the total driving duration of the vehicle after leaving the factory; according to the formula Determine the DPF differential pressure growth rate of the target vehicle; where ΔP is the DPF differential pressure growth rate, p1 is the current DPF differential pressure value, p2 is the initial DPF differential pressure value, and Δt is the total driving duration of the vehicle after leaving the factory.

[0078] Specifically, an explanation is given with the DPF differential pressure growth rate determined according to the total driving mileage of the vehicle after leaving the factory, the current DPF differential pressure value and the initial DPF differential pressure value of the target vehicle:

[0079] Determining the DPF differential pressure growth rate of the target vehicle according to the current DPF differential pressure value and the initial DPF differential pressure value may also include: obtaining the total driving mileage of the vehicle after leaving the factory; according to the formula Determine the DPF differential pressure growth rate of the target vehicle; where ΔP is the DPF differential pressure growth rate, p1 is the current DPF differential pressure value, p2 is the initial DPF differential pressure value, and Δs is the total mileage of the target vehicle after it leaves the factory.

[0080] S103: Obtain the current upstream temperature value of the diesel oxidation catalyst (DOC) of the target vehicle and the initial upstream temperature value of the DOC corresponding to the current driving condition; and determine the upstream temperature difference of the DOC of the target vehicle according to the current upstream temperature value of the DOC and the initial upstream temperature value.

[0081] It should be noted that the initial upstream temperature value of the DOC corresponding to the current driving condition is obtained by querying the DOC temperature value table corresponding to the vehicle condition points in the universal data during bench development. The DOC temperature value table corresponding to the vehicle condition points in the universal data during bench development is generated during the bench development of the vehicle, and there is an initial upstream temperature value of the DOC corresponding to each driving condition of the vehicle.

[0082] S104: Judge whether the DPF differential pressure growth rate meets the first condition; and judge whether the upstream temperature difference of the DOC meets the second condition.

[0083] Specifically, judging whether the DPF differential pressure growth rate meets the first condition is specifically: judging whether the DPF differential pressure growth rate is greater than or equal to 10%.

[0084] Specifically, the second condition is determined by a pre-stored corresponding table of DOC upstream temperature difference conditions. The requirements that the upstream temperature difference of the DOC should meet are related to the engine; this corresponding table of DOC upstream temperature difference conditions includes the corresponding relationship between the engine speed and the DOC upstream temperature difference conditions.

[0085] The corresponding table of DOC upstream temperature difference conditions is specifically as follows in Table 1:

[0086] Table 1

[0087]

[0088] Judging whether the upstream temperature difference of the DOC meets the second condition specifically includes: obtaining the pre-stored corresponding table of DOC upstream temperature difference conditions; the corresponding table of DOC upstream temperature difference conditions includes the corresponding relationship between the engine speed and the DOC upstream temperature difference conditions; obtaining the current engine speed of the target vehicle; determining the second condition corresponding to the current engine speed according to the corresponding table of DOC upstream temperature difference conditions and the current engine speed; and judging whether the upstream temperature difference of the DOC meets the second condition corresponding to the current engine speed.

[0089] Taking the current engine speed of the target vehicle as 1000 - 1200 rpm as an example for detailed description, after looking up the table, the temperature difference upstream of the DOC corresponding to the current engine speed should meet the requirement of ≥15°C.

[0090] S105: If the DPF differential pressure growth rate meets the first condition and the temperature difference upstream of the DOC meets the second condition, then prompt that the exhaust gas recirculation system EGR of the target vehicle is carbon deposited.

[0091] It should be noted that in this embodiment of the present application, when it is determined that the DPF differential pressure growth rate meets the first condition and the temperature difference upstream of the DOC meets the second condition, a prompt that the exhaust gas recirculation system EGR of the target vehicle is carbon deposited is sent to the user to remind the user to clean the carbon deposit.

[0092] The specific EGR cleaning method can be: when it is prompted that the EGR needs to be cleaned, the user drives the vehicle to the local service station. The service station disassembles the EGR valve, cooler and venturi pipeline for cleaning. The EGR cooler uses a high-temperature furnace regeneration scheme to burn off the carbon deposit in the EGR cooler. After regeneration, the performance is basically the same as that of a fresh EGR cooler. The venturi and other pipelines are soaked and cleaned with a cleaning agent, and the EGR system can be recycled. The present application does not specifically limit the EGR cleaning method, and all are within the protection scope of the present application.

[0093] Regarding the carbon deposit situation of the EGR system, when the diesel engine EGR system has too much carbon deposit, there are mainly two effects. The engine exhaust temperature rises, and the increase in the engine exhaust temperature further causes the temperature upstream of the DOC to rise, and the NOx upstream of the SCR decreases; the EGR opening increases, and the soot increases, resulting in a faster growth rate of the soot particles in the DPF than normal, and then causing the DPF differential pressure to gradually increase. In the embodiment of the present application, based on the difference in the temperature upstream of the DOC during the vehicle driving condition compared with that during engine development, and the increasing rate of the DPF differential pressure compared with the pressure rise rate under the same carbon load, the user is prompted to perform EGR cleaning and maintenance.

[0094] The embodiment of the present application simultaneously considers the DPF differential pressure increase rate and the influence of the temperature upstream of the DOC by the EGR cooler and venturi carbon deposit to judge whether the EGR system is severely carbon deposited. After the EGR system is severely carbon deposited, the original engine exhaust soot will deteriorate significantly. Therefore, the growth rate of the DPF carbon deposit differential pressure can be used as one of the determination conditions; and currently, the EGR opening of the engine has a greater impact on the exhaust temperature behind the turbine, and the increase in the exhaust temperature upstream of the DOC is also used as one of the determination conditions for the EGR system carbon deposit, avoiding misjudgment caused by the EGR valve sticking or air leakage in the intake system resulting in an accelerated DPF carbon deposit rate. Moreover, considering from the vehicle driving condition, multiple parameters are combined in the EGR system carbon deposit detection, improving the accuracy of the EGR system carbon deposit detection.

[0095] Moreover, in the existing EGR carbon deposition detection solution, the cleaning cycle is determined based on the original exhaust NOx and the EGR cold-back temperature, and it is necessary to install an original exhaust NOx sensor and an EGR cold-back temperature sensor. Compared with the existing solution, the present application can realize the carbon deposition monitoring and detection of the EGR system in the currently practically applied aftertreatment system without additional hardware, and it is also applicable to non-four-EGR route vehicles (i.e., vehicles without an SCR upstream NOx sensor).

[0096] In another embodiment of the present application, another method for detecting carbon deposition in an exhaust gas recirculation system is provided. As shown in the appendix Figure 2 shown below, a detailed introduction to the method for detecting carbon deposition in the exhaust gas recirculation system in the embodiment of the present application will be made

[0097] S201: Obtain the current driving condition of the target vehicle;

[0098] S202: Obtain the actual value of the exhaust gas flow rate of the EGR system and the set value of the exhaust gas flow rate of the EGR system corresponding to the current driving condition;

[0099] It should be noted that the set value of the exhaust gas flow rate of the EGR system is obtained by querying the universal data table during bench development and has been set during bench development.

[0100] S203: Determine the exhaust gas flow rate deviation value of the EGR system according to the actual exhaust gas flow rate value and the set exhaust gas flow rate value;

[0101] S204: Determine whether the exhaust gas flow rate deviation value meets the third condition; if the exhaust gas flow rate deviation value meets the third condition, obtain the engine exhaust gas flow rate of the target vehicle;

[0102] Specifically, the third condition is that the exhaust gas flow rate deviation value is less than or equal to 5%.

[0103] S205: Determine whether the engine exhaust gas flow rate of the target vehicle meets the fourth condition; if the engine exhaust gas flow rate of the target vehicle meets the fourth condition, obtain the current differential pressure value of the diesel particulate filter DPF of the target vehicle and the initial DPF differential pressure value corresponding to the current driving condition; and determine the DPF differential pressure growth rate of the target vehicle according to the current DPF differential pressure value and the initial DPF differential pressure value.

[0104] Specifically, the fourth condition is that the engine exhaust gas flow rate is greater than or equal to 500 kg / m 3 。

[0105] S206: Obtain the actual intake pressure value of the EGR system and the set intake pressure value of the EGR system corresponding to the current driving condition;

[0106] It should be noted that the set value of the intake pressure of the EGR system is obtained by querying the universal data table during bench development, and it has been set and completed during bench development.

[0107] S207: Determine the intake pressure deviation value of the EGR system according to the actual intake pressure value and the set intake pressure value;

[0108] S208: Determine whether the intake pressure deviation value meets the fifth condition; if the intake pressure deviation value meets the fifth condition, obtain the current upstream temperature value of the diesel oxidation catalytic converter DOC of the target vehicle and the initial upstream temperature value of the DOC corresponding to the current driving condition; and determine the DOC upstream temperature difference value of the target vehicle according to the current DOC upstream temperature value and the initial DOC upstream temperature value;

[0109] Specifically, the fifth condition is that the intake pressure deviation value is less than or equal to 5%.

[0110] S209: Determine whether the DPF differential pressure growth rate meets the first condition; and determine whether the DOC upstream temperature difference value meets the second condition;

[0111] S210: If the DPF differential pressure growth rate meets the first condition and the DOC upstream temperature difference value meets the second condition, prompt that the exhaust gas recirculation system EGR of the target vehicle is carbonized.

[0112] In the embodiment of the present application, for the carbon deposition detection method of the exhaust gas recirculation system, it simultaneously considers the DPF differential pressure increase rate and the influence of the DOC upstream temperature by the EGR cooler and Venturi carbon deposition to determine whether the EGR system is severely carbonized. It utilizes the EGR route machine to adopt closed-loop control. After the EGR cooler and Venturi are carbonized, the opening degree of the EGR valve will increase, taking the opening degree of the EGR valve as one of the determination conditions. At the same time, after the EGR system is severely carbonized, the original engine exhaust soot will deteriorate significantly, taking the DPF carbon deposition differential pressure growth rate after treatment as one of the determination conditions, and also utilizing the fact that the current engine EGR opening degree has a greater impact on the exhaust gas temperature behind the turbine, taking the increase in the DOC upstream exhaust gas temperature as one of the determination conditions for the EGR system carbon deposition, avoiding misjudgment caused by the EGR valve sticking or air leakage in the intake system resulting in an accelerated DPF carbon deposition rate. Moreover, considering from the vehicle's driving conditions, multiple parameters are combined and considered in the EGR system carbon deposition detection, improving the accuracy of the EGR system carbon deposition detection.

[0113] Next, an introduction to a carbon deposition detection device for an exhaust gas recirculation system in an embodiment of the present application will be given. Please refer to Figure 3, based on a method for detecting carbon deposition in an exhaust gas recirculation system in the above embodiments, the embodiments of the present application implement the method for detecting carbon deposition in the exhaust gas recirculation system through a device for detecting carbon deposition in the exhaust gas recirculation system. The device for detecting carbon deposition in the exhaust gas recirculation system in the embodiments of the present application includes:

[0114] An acquisition unit 10, configured to acquire the current driving condition of the target vehicle;

[0115] The acquisition unit 10 is further configured to acquire the current differential pressure value of the diesel particulate filter DPF of the target vehicle, and the initial DPF differential pressure value corresponding to the current driving condition;

[0116] A calculation unit 20, configured to determine the DPF differential pressure growth rate of the target vehicle according to the current DPF differential pressure value and the initial DPF differential pressure value;

[0117] The acquisition unit 10 is further configured to acquire the current upstream temperature value of the diesel oxidation catalyst DOC of the target vehicle, and the initial DOC upstream temperature value corresponding to the current driving condition;

[0118] The calculation unit 20 is further configured to determine the DOC upstream temperature difference of the target vehicle according to the current DOC upstream temperature value and the initial DOC upstream temperature value;

[0119] A judgment unit 30, configured to judge whether the DPF differential pressure growth rate meets a first condition; and judge whether the DOC upstream temperature difference meets a second condition;

[0120] A processing unit 40, configured to, if the DPF differential pressure growth rate meets the first condition and the DOC upstream temperature difference meets the second condition, prompt carbon deposition in the exhaust gas recirculation system EGR of the target vehicle.

[0121] Specifically, in the device:

[0122] The acquisition unit is further configured to acquire the actual value of the exhaust gas flow of the EGR system, and the set value of the exhaust gas flow of the EGR system corresponding to the current driving condition;

[0123] The calculation unit is further configured to determine the exhaust gas flow deviation value of the EGR system according to the actual value of the exhaust gas flow and the set value of the exhaust gas flow;

[0124] The judgment unit is further configured to judge whether the exhaust gas flow deviation value meets a third condition;

[0125] The acquisition unit is further configured to, if the exhaust gas flow deviation value meets the third condition, acquire the engine exhaust gas flow of the target vehicle;

[0126] The determination unit is further configured to determine whether the engine exhaust gas flow rate of the target vehicle satisfies a fourth condition;

[0127] The acquisition unit is further configured to, if the engine exhaust gas flow rate of the target vehicle satisfies the fourth condition, execute acquiring the current DPF differential pressure value of the target vehicle and the initial DPF differential pressure value corresponding to the current driving condition.

[0128] Specifically, in the device:

[0129] The acquisition unit is further configured to acquire the actual intake pressure value of the EGR system and the set intake pressure value of the EGR system corresponding to the current driving condition;

[0130] The calculation unit is further configured to determine the intake pressure deviation value of the EGR system according to the actual intake pressure value and the set intake pressure value;

[0131] The determination unit is further configured to determine whether the intake pressure deviation value satisfies a fifth condition;

[0132] The acquisition unit is further configured to, if the intake pressure deviation value satisfies the fifth condition, execute acquiring the current DOC upstream temperature value of the target vehicle and the initial DOC upstream temperature value corresponding to the current driving condition.

[0133] Specifically, the calculation unit is specifically configured to acquire the total vehicle driving duration of the target vehicle after the vehicle leaves the factory; according to the formula to determine the DPF differential pressure growth rate of the target vehicle; where ΔP is the DPF differential pressure growth rate, p1 is the current DPF differential pressure value, p2 is the initial DPF differential pressure value, and Δt is the total vehicle driving duration of the target vehicle after the vehicle leaves the factory.

[0134] Specifically, the determination unit is specifically configured to determine whether the DPF differential pressure growth rate satisfies being greater than or equal to 10%.

[0135] Specifically, the determination unit is specifically configured to acquire a pre-stored DOC upstream temperature difference condition correspondence table; the DOC upstream temperature difference condition correspondence table includes the correspondence between the engine speed and the DOC upstream temperature difference condition; acquire the current engine speed of the target vehicle; according to the DOC upstream temperature difference condition correspondence table and the current engine speed, determine the second condition corresponding to the current engine speed; determine whether the DOC upstream temperature difference satisfies the second condition corresponding to the current engine speed.

[0136] In the embodiment of the present application, the carbon deposition detection device for the exhaust gas recirculation system takes into account the differential pressure increase rate of the DPF and the influence of the temperature upstream of the DOC on the EGR cooler and the Venturi carbon deposition to determine whether the EGR system has serious carbon deposition. After the EGR system has serious carbon deposition, the original soot emission of the engine will deteriorate significantly. Therefore, the carbon deposition differential pressure growth rate of the subsequent after-treatment DPF can be used as one of the determination conditions. In addition, the current EGR opening of the engine has a great influence on the exhaust gas temperature behind the turbine. The increase in the exhaust gas temperature upstream of the DOC is also used as one of the determination conditions for the EGR system carbon deposition, avoiding misjudgment caused by the acceleration of the DPF carbon deposition rate due to EGR valve jamming or air leakage in the intake system. Moreover, considering the vehicle driving conditions, multiple parameters are combined in the EGR system carbon deposition detection, improving the accuracy of the EGR system carbon deposition detection.

[0137] Another embodiment of the present application also provides a vehicle, using the carbon deposition detection method for the exhaust gas recirculation system in the above embodiment to detect the carbon loading of the EGR of the exhaust gas recirculation system.

[0138] The vehicle provided in the embodiment of the present application applies the carbon deposition detection method for the exhaust gas recirculation system, judges according to different driving conditions of the vehicle, and simultaneously considers the DPF differential pressure growth rate of the target vehicle and the temperature difference upstream of the DOC of the target vehicle, improving the accuracy of the EGR system carbon deposition detection.

[0139] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting carbon deposition in an exhaust gas recirculation system, characterized in that, The method includes: Obtaining the current driving condition of the target vehicle; Obtaining the current diesel particulate filter (DPF) pressure difference value of the target vehicle and the initial DPF pressure difference value corresponding to the current driving condition; and determining the DPF pressure difference growth rate of the target vehicle according to the current DPF pressure difference value and the initial DPF pressure difference value; Obtaining the current upstream temperature value of the diesel oxidation catalyst (DOC) of the target vehicle and the initial DOC upstream temperature value corresponding to the current driving condition; and determining the DOC upstream temperature difference value of the target vehicle according to the current DOC upstream temperature value and the initial DOC upstream temperature value; Judging whether the DPF pressure difference growth rate meets the first condition; and judging whether the DOC upstream temperature difference value meets the second condition; If the DPF pressure difference growth rate meets the first condition and the DOC upstream temperature difference value meets the second condition, then prompt that the exhaust gas recirculation (EGR) system of the target vehicle is carbonized; Judging whether the DPF pressure difference growth rate meets the first condition specifically includes: judging whether the DPF pressure difference growth rate meets greater than or equal to 10%; Judging whether the DOC upstream temperature difference value meets the second condition specifically includes: obtaining a pre-stored DOC upstream temperature difference condition correspondence table; the DOC upstream temperature difference condition correspondence table includes the correspondence relationship between the engine speed and the DOC upstream temperature difference condition; obtaining the current engine speed of the target vehicle; determining the second condition corresponding to the current engine speed according to the DOC upstream temperature difference condition correspondence table and the current engine speed; and judging whether the DOC upstream temperature difference value meets the second condition corresponding to the current engine speed.

2. The method according to claim 1, characterized in that, Before obtaining the current diesel particulate filter (DPF) pressure difference value of the target vehicle and the initial DPF pressure difference value corresponding to the current driving condition; and determining the DPF pressure difference growth rate of the target vehicle according to the current DPF pressure difference value and the initial DPF pressure difference value, the method further includes: Obtaining the actual exhaust gas flow value of the EGR system and the set exhaust gas flow value of the EGR system corresponding to the current driving condition; Determining the exhaust gas flow deviation value of the EGR system according to the actual exhaust gas flow value and the set exhaust gas flow value; Judging whether the exhaust gas flow deviation value meets the third condition, and the third condition is that the exhaust gas flow deviation value is less than or equal to 5%; If the exhaust gas flow deviation value meets the third condition, then obtain the engine exhaust gas flow of the target vehicle; Determine whether the engine exhaust gas flow rate of the target vehicle meets the fourth condition, where the fourth condition is that the engine exhaust gas flow rate is greater than or equal to 500 kg / m 3 ; If the engine exhaust gas flow of the target vehicle meets the fourth condition, then execute obtaining the current DPF pressure difference value of the target vehicle and the initial DPF pressure difference value corresponding to the current driving condition.

3. The method according to claim 1, characterized in that, When obtaining the current upstream temperature value of the diesel oxidation catalyst (DOC) of the target vehicle and the initial DOC upstream temperature value corresponding to the current driving condition; Before determining the upstream temperature difference of the DOC of the target vehicle based on the current upstream DOC temperature value and the initial upstream DOC temperature value, the method further includes: Obtaining the actual intake pressure value of the EGR system and the set intake pressure value of the EGR system corresponding to the current driving condition; Determining the intake pressure deviation value of the EGR system according to the actual intake pressure value and the set intake pressure value; Judging whether the intake pressure deviation value meets the fifth condition, where the fifth condition is that the intake pressure deviation value is less than or equal to 5%; If the intake pressure deviation value meets the fifth condition, then execute obtaining the current upstream DOC temperature value of the target vehicle and the initial upstream DOC temperature value corresponding to the current driving condition.

4. The method according to any one of claims 1-3, characterized in that, The determining the DPF differential pressure growth rate of the target vehicle according to the current DPF differential pressure value and the initial DPF differential pressure value specifically includes: Obtaining the total driving duration of the target vehicle after the vehicle leaves the factory; According to the formula to determine the DPF differential pressure growth rate of the target vehicle; where ΔP is the DPF differential pressure growth rate, p1 is the current DPF differential pressure value, p2 is the initial DPF differential pressure value, and Δt is the total driving duration of the target vehicle after the vehicle leaves the factory.

5. A device for detecting carbon deposition in an exhaust gas recirculation system, characterized in that, The device includes: An obtaining unit, configured to obtain the current driving condition of the target vehicle; The obtaining unit is further configured to obtain the current diesel particulate filter DPF differential pressure value of the target vehicle and the initial DPF differential pressure value corresponding to the current driving condition; A calculating unit, configured to determine the DPF differential pressure growth rate of the target vehicle according to the current DPF differential pressure value and the initial DPF differential pressure value; The obtaining unit is further configured to obtain the current upstream DOC temperature value of the diesel oxidation catalyst DOC of the target vehicle and the initial upstream DOC temperature value corresponding to the current driving condition; The calculating unit is further configured to determine the upstream DOC temperature difference of the target vehicle according to the current upstream DOC temperature value and the initial upstream DOC temperature value; A judging unit, configured to judge whether the DPF differential pressure growth rate meets the first condition; and judge whether the upstream DOC temperature difference meets the second condition; A processing unit, configured to, if the DPF differential pressure growth rate meets the first condition and the upstream DOC temperature difference meets the second condition, prompt carbon deposition in the exhaust gas recirculation system EGR of the target vehicle; The judging unit is specifically configured to judge whether the DPF differential pressure growth rate is greater than or equal to 10%; The judging unit is specifically further configured to obtain a pre-stored corresponding table of upstream DOC temperature difference conditions; the corresponding table of upstream DOC temperature difference conditions includes the corresponding relationship between the engine speed and the upstream DOC temperature difference conditions; obtain the current engine speed of the target vehicle; determine the second condition corresponding to the current engine speed according to the corresponding table of upstream DOC temperature difference conditions and the current engine speed; judge whether the upstream DOC temperature difference meets the second condition corresponding to the current engine speed.

6. The device according to claim 5, wherein, In the device: The obtaining unit is further configured to obtain the actual exhaust gas flow value of the EGR system and the set exhaust gas flow value of the EGR system corresponding to the current driving condition; The calculation unit is further configured to determine an exhaust gas flow deviation value of the EGR system according to the actual exhaust gas flow value and the set exhaust gas flow value; The judgment unit is further configured to judge whether the exhaust gas flow deviation value satisfies a third condition, where the third condition is that the exhaust gas flow deviation value is less than or equal to 5%; The acquisition unit is further configured to, if the exhaust gas flow deviation value satisfies the third condition, acquire the engine exhaust gas flow of the target vehicle; The determination unit is further configured to determine whether the engine exhaust gas flow rate of the target vehicle meets a fourth condition, where the fourth condition is that the engine exhaust gas flow rate is greater than or equal to 500 kg / m 3 ; The acquisition unit is further configured to, if the engine exhaust gas flow of the target vehicle satisfies the fourth condition, execute the acquisition of the current DPF differential pressure value of the target vehicle and the initial DPF differential pressure value corresponding to the current driving condition.

7. The device according to claim 6, wherein, In the device: The acquisition unit is further configured to acquire the actual intake pressure value of the EGR system and the set intake pressure value of the EGR system corresponding to the current driving condition; The calculation unit is further configured to determine an intake pressure deviation value of the EGR system according to the actual intake pressure value and the set intake pressure value; The judgment unit is further configured to judge whether the intake pressure deviation value satisfies a fifth condition, where the fifth condition is that the intake pressure deviation value is less than or equal to 5%; The acquisition unit is further configured to, if the intake pressure deviation value satisfies the fifth condition, execute the acquisition of the current DOC upstream temperature value of the target vehicle and the initial DOC upstream temperature value corresponding to the current driving condition.

8. A vehicle, wherein, The carbon loading of the exhaust gas recirculation system is detected by using the method for detecting carbon deposition in the exhaust gas recirculation system according to any one of claims 1-4.

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