阅读说明：本技术 废气再循环系统的检测方法、装置、设备和存储介质 (Detection method, device, equipment and storage medium of exhaust gas recirculation system ) 是由 申付松 田良云 刘勤 于 2021-08-31 设计创作，主要内容包括：本申请公开了一种废气再循环系统的检测方法、装置、设备和存储介质,该方法包括：当插电式混合动力汽车处于怠速纯充电工况时,开启废气再循环系统的废气再循环阀门；获取第一压力值,第一压力值用于表征在第一时刻废气再循环系统中的气体的压力值,第一时刻是开启废气再循环阀门的时刻；获取第二压力值,第二压力值用于表征在第二时刻废气再循环系统中的气体的压力值,第二时刻是距离第一时刻后第一预定时间段的时刻；根据第一压力值和第二压力值的差值对废气再循环系统进行故障诊断。本申请通过对废气再循环系统进行故障诊断由于不依赖进气流传感器,降低了检测成本。(The application discloses a detection method, a device, equipment and a storage medium of an exhaust gas recirculation system, wherein the method comprises the following steps: when the plug-in hybrid electric vehicle is in an idle pure charging working condition, an exhaust gas recirculation valve of an exhaust gas recirculation system is opened; acquiring a first pressure value, wherein the first pressure value is used for representing the pressure value of gas in the exhaust gas recirculation system at a first moment, and the first moment is the moment when the exhaust gas recirculation valve is opened; acquiring a second pressure value, wherein the second pressure value is used for representing the pressure value of the gas in the exhaust gas recirculation system at a second moment, and the second moment is a moment which is a first preset time period after the first moment; and carrying out fault diagnosis on the exhaust gas recirculation system according to the difference value of the first pressure value and the second pressure value. This application is through carrying out fault diagnosis to exhaust gas recirculation system owing to do not rely on the air intake flow sensor, has reduced the detection cost.)

1. A method of detecting an exhaust gas recirculation system, which is applied to a plug-in hybrid vehicle equipped with an exhaust gas recirculation system, comprising:

when the plug-in hybrid electric vehicle is in an idle pure charging working condition, an exhaust gas recirculation valve of the exhaust gas recirculation system is opened;

obtaining a first pressure value, wherein the first pressure value is used for representing a pressure value of gas entering an air inlet manifold of the exhaust gas recirculation system at a first moment, and the first moment is a moment when the exhaust gas recirculation valve is opened;

obtaining a second pressure value, wherein the second pressure value is used for representing a pressure value of gas entering the air inlet manifold at a second moment, and the second moment is a moment which is a first preset time period after the first moment;

and carrying out fault diagnosis on the exhaust gas recirculation system according to the difference value of the first pressure value and the second pressure value.

2. The method of claim 1, wherein said obtaining a first force value comprises:

acquiring the first pressure value through a pressure sensor arranged in the intake manifold;

the obtaining a second pressure value comprises:

and acquiring the second pressure value through the pressure sensor.

3. The method of claim 2, wherein opening an exhaust gas recirculation valve of the exhaust gas recirculation system when the plug-in hybrid vehicle is in an idle pure charge condition comprises:

and when the plug-in hybrid electric vehicle is in the idle pure charging condition and the water temperature of an engine of the plug-in hybrid electric vehicle is greater than a temperature threshold value, opening the exhaust gas recirculation valve.

4. The method of claim 3, wherein said diagnosing the fault in the exhaust gas recirculation system based on the difference between the first pressure value and the second pressure value comprises:

determining that a low flow fault exists in the exhaust gas recirculation system when the difference is less than a difference threshold.

5. The method of claim 4, further comprising:

determining that a low flow fault does not exist in the exhaust gas recirculation system when the difference is not less than the difference threshold.

6. The method according to any one of claims 1 to 5, characterized in that the opening degree of the exhaust gas recirculation valve is less than 95% when the exhaust gas recirculation valve of the exhaust gas recirculation system is opened.

7. The method of claim 6, further comprising:

acquiring a third pressure value when an engine of the plug-in hybrid electric vehicle is started, wherein the third pressure value is a pressure value used for representing gas entering the air inlet manifold at a third moment after the engine is started;

acquiring a fourth pressure value, wherein the fourth pressure value is used for representing a pressure value of gas entering the air inlet manifold at a fourth moment, and the fourth moment is a moment which is a second preset time period after the third moment;

acquiring the overshoot of the engine speed in the second preset time period;

and diagnosing the fault of the exhaust gas recirculation system according to the difference value of the fourth pressure value and the third pressure value and the upper impulse.

8. The method of claim 7, wherein said obtaining a third force value comprises:

acquiring the third pressure value through a pressure sensor arranged in the intake manifold;

the obtaining a fourth pressure value includes:

and acquiring the fourth pressure value through the pressure sensor.

9. The method of claim 8, wherein said diagnosing a malfunction of said exhaust gas recirculation system based on a difference between said fourth pressure value and said third pressure value and said up-pulse comprises:

when the difference value between the third pressure value and the fourth pressure value and the overshoot meet a trigger condition, increasing the number of faults by one, wherein the trigger condition is that the difference value between the third pressure value and the fourth pressure value is smaller than a pressure drop threshold value and the overshoot is smaller than an overshoot threshold value;

determining that a high flow fault exists in the exhaust gas recirculation system when the number of faults is greater than a first number threshold.

10. The method of claim 9, further comprising:

when the difference between the third pressure value and the fourth pressure value and the upper impulse do not meet the triggering condition, increasing the number of the faults by one;

determining that the exhaust gas recirculation system is free of a high flow fault when the number of no faults is greater than a second number threshold.

11. A detection device applied to a plug-in hybrid vehicle equipped with an exhaust gas recirculation system, comprising:

the control module is used for starting an exhaust gas recirculation valve of the exhaust gas recirculation system when the plug-in hybrid electric vehicle is in an idle pure charging working condition;

an obtaining module, configured to obtain a first pressure value, where the first pressure value is used to represent a pressure value of gas entering an intake manifold of the exhaust gas recirculation system at a first time, and the first time is a time when the exhaust gas recirculation valve is opened; acquiring a second pressure value, wherein the second pressure value is used for representing a pressure value of gas entering the air inlet manifold at a second moment, and the second moment is a moment which is a first preset time period after the first moment;

and the processing module is used for carrying out fault diagnosis on the exhaust gas recirculation system according to the difference value of the first pressure value and the second pressure value.

12. A controller comprising a processor and a memory, said memory having stored therein at least one instruction or program that is loaded and executed by said processor to implement a method of sensing an exhaust gas recirculation system as claimed in any one of claims 1 to 10.

13. A computer readable storage medium having stored therein at least one instruction, which is loaded and executed by a processor to implement a method of detecting an exhaust gas recirculation system according to any one of claims 1 to 10.

Technical Field

The application relates to the technical field of vehicle control, in particular to a detection method, a detection device, detection equipment and a storage medium for an exhaust gas recirculation system.

Background

A plug-in hybrid electric vehicle (PHEV) is a new energy vehicle between a pure electric vehicle (BEV) and a fuel vehicle, and is generally equipped with an engine with a small displacement, and technologies such as an atkinson cycle and an external Exhaust Gas Recirculation (EGR) system are applied to improve the thermal efficiency of the engine, thereby achieving the purpose of reducing the fuel consumption.

Whether the exhaust gas recirculation system can deliver the exhaust gas to the cylinder of the engine for combustion according to a preset flow rate has important influence on the oil consumption and the emission of the engine. In order to ensure that the exhaust gas recirculation system can work normally and ensure that the vehicle cannot cause emission deterioration or fuel consumption increase due to faults of abnormal EGR flow (which is represented by excessively low or high EGR flow) and the like, the national sixth-stage motor vehicle pollutant emission standard has clear diagnosis requirements on the faults of the EGR flow.

In the related art, an EGR flow fault diagnosis method includes: calculating the EGR flow of the exhaust gas recirculation system through the secondary air charging model; acquiring the current EGR flow through an intake flow sensor; and judging whether the EGR flow is abnormal or not according to the deviation between the calculated EGR flow and the current EGR flow.

However, since the cost of providing an intake air flow sensor in a plug-in hybrid vehicle is high, an EGR flow failure diagnosis method that does not depend on the intake air flow sensor is urgently required.

Disclosure of Invention

The application provides a detection method, a detection device, equipment and a storage medium of an exhaust gas recirculation system, which can solve the problem that the detection cost of the exhaust gas recirculation system is higher through an air inlet flow sensor in the related technology.

In one aspect, an embodiment of the present application provides a method for detecting an exhaust gas recirculation system, where the method is applied to a plug-in hybrid vehicle equipped with the exhaust gas recirculation system, and the method includes:

when the plug-in hybrid electric vehicle is in an idle pure charging working condition, an exhaust gas recirculation valve of the exhaust gas recirculation system is opened;

obtaining a first pressure value, wherein the first pressure value is used for representing a pressure value of gas entering an air inlet manifold of the exhaust gas recirculation system at a first moment, and the first moment is a moment when the exhaust gas recirculation valve is opened;

obtaining a second pressure value, wherein the second pressure value is used for representing a pressure value of gas entering the air inlet manifold at a second moment, and the second moment is a moment which is a first preset time period after the first moment;

and carrying out fault diagnosis on the exhaust gas recirculation system according to the difference value of the first pressure value and the second pressure value.

Optionally, the obtaining the first pressure value includes:

acquiring the first pressure value through a pressure sensor arranged in the intake manifold;

the obtaining a second pressure value comprises:

and acquiring the second pressure value through the pressure sensor.

Optionally, when the plug-in hybrid electric vehicle is in an idle pure charging condition, the exhaust gas recirculation valve of the exhaust gas recirculation system is opened, including:

and when the plug-in hybrid electric vehicle is in the idle pure charging condition and the water temperature of an engine of the plug-in hybrid electric vehicle is greater than a temperature threshold value, opening the exhaust gas recirculation valve.

Optionally, the diagnosing the fault of the exhaust gas recirculation system according to the difference between the first pressure value and the second pressure value includes:

determining that a low flow fault exists in the exhaust gas recirculation system when the difference is less than a difference threshold.

Optionally, the method further includes:

determining that a low flow fault does not exist in the exhaust gas recirculation system when the difference is not less than the difference threshold.

Optionally, when the egr valve of the egr system is opened, the opening of the egr valve is less than 95%.

Optionally, the method further includes:

acquiring a third pressure value when an engine of the plug-in hybrid electric vehicle is started, wherein the third pressure value is a pressure value used for representing gas entering the air inlet manifold at a third moment after the engine is started;

acquiring a fourth pressure value, wherein the fourth pressure value is used for representing a pressure value of gas entering the air inlet manifold at a fourth moment, and the fourth moment is a moment which is a second preset time period after the third moment;

acquiring the overshoot of the engine speed in the second preset time period;

and diagnosing the fault of the exhaust gas recirculation system according to the difference value of the fourth pressure value and the third pressure value and the upper impulse.

Optionally, the obtaining a third pressure value includes:

acquiring the third pressure value through a pressure sensor arranged in the intake manifold;

the obtaining a fourth pressure value includes:

and acquiring the fourth pressure value through the pressure sensor.

Optionally, the diagnosing a fault of the exhaust gas recirculation system according to the difference between the fourth pressure value and the third pressure value and the upper impulse includes:

when the difference value between the third pressure value and the fourth pressure value and the overshoot meet a trigger condition, increasing the number of faults by one, wherein the trigger condition is that the difference value between the third pressure value and the fourth pressure value is smaller than a pressure drop threshold value and the overshoot is smaller than an overshoot threshold value;

determining that a high flow fault exists in the exhaust gas recirculation system when the number of faults is greater than a first number threshold.

Optionally, the method further includes:

when the difference between the third pressure value and the fourth pressure value and the upper impulse do not meet the triggering condition, increasing the number of the faults by one;

determining that the exhaust gas recirculation system is free of a high flow fault when the number of no faults is greater than a second number threshold.

In another aspect, an embodiment of the present application provides a detection apparatus applied to a plug-in hybrid vehicle equipped with an exhaust gas recirculation system, the apparatus including:

the control module is used for starting an exhaust gas recirculation valve of the exhaust gas recirculation system when the plug-in hybrid electric vehicle is in an idle pure charging working condition;

an obtaining module, configured to obtain a first pressure value, where the first pressure value is used to represent a pressure value of gas entering the exhaust gas recirculation system at a first time, and the first time is a time when the exhaust gas recirculation valve is opened; obtaining a second pressure value, wherein the second pressure value is used for representing a pressure value of gas entering the exhaust gas recirculation system at a second moment, and the second moment is a moment which is a first preset time period after the first moment;

and the processing module is used for carrying out fault diagnosis on the exhaust gas recirculation system according to the difference value of the first pressure value and the second pressure value.

In another aspect, embodiments of the present application provide a controller, including a processor and a memory, where the memory stores at least one instruction or program, and the instruction or program is loaded and executed by the processor to implement the detection method of the exhaust gas recirculation system as described in any one of the above.

In another aspect, an embodiment of the present application provides a computer-readable storage medium, where at least one instruction is stored in the storage medium, and the instruction is loaded and executed by a processor to implement the detection method of the exhaust gas recirculation system as described in any one of the above.

The technical scheme at least comprises the following advantages:

when the idle pure charging working condition is adopted, the exhaust gas recirculation valve of the exhaust gas recirculation system is opened for a first preset time period, and the fault diagnosis is carried out on the exhaust gas recirculation system according to the pressure difference value of gas entering an air inlet manifold in the first preset time period, so that the problem that the cost is high when the EGR flow is judged by arranging an air inlet flow sensor on a plug-in hybrid electric vehicle in the related technology is solved, and the detection cost is reduced, and meanwhile, the accuracy, precision and stability are high.

Drawings

In order to more clearly illustrate the detailed description of the present application or the technical solutions in the prior art, the drawings needed to be used in the detailed description of the present application or the prior art description will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic illustration of an environment in which a method of testing an exhaust gas recirculation system according to an exemplary embodiment of the present application may be used;

FIG. 2 is a flow chart of a method of testing an exhaust gas recirculation system provided by an exemplary embodiment of the present application;

FIG. 3 is a flow chart of a method of testing an exhaust gas recirculation system provided by an exemplary embodiment of the present application;

FIG. 4 is a flow chart of a method of testing an exhaust gas recirculation system provided by an exemplary embodiment of the present application;

fig. 5 is a block diagram of a detection apparatus provided in an exemplary embodiment of the present application.

Detailed Description

The technical solutions in the present application will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; the connection can be mechanical connection or electrical connection; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

In addition, the technical features mentioned in the different embodiments of the present application described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 1, which is a schematic diagram illustrating an application environment of a detection method of an exhaust gas recirculation system according to an exemplary embodiment of the present application, as shown in fig. 1, the detection method includes an exhaust gas recirculation system 110 and a controller 120, and the exhaust gas recirculation system 110 and the controller 120 are equipped in a plug-in hybrid vehicle, wherein:

the egr system 110 includes an intake manifold 111 and an egr valve 112, the intake manifold 111 is a pipe before gas in the egr system 110 enters the cylinder 100, and the egr valve 112 is used to control whether gas enters the cylinder 100 or not, or to control the flow rate of gas in the egr system 110 according to the degree of opening thereof.

The egr valve 112 is controlled by a controller 120, and is controlled by the controller 120 to open or close, and to open, and a pressure sensor, or a pressure sensor and a temperature sensor (not shown in fig. 1) are typically disposed in the intake manifold 111, and a pressure signal collected by the pressure sensor and a temperature signal collected by the temperature sensor are transmitted to the controller 120.

Optionally, the exhaust gas recirculation system 110 further comprises: a muffler 113, a catalyst 114, a cooler 115, a throttle 116, and an air filter 117. Among them, the muffler 113 is used to reduce noise generated by gas discharged from the egr system 110, the catalyst 114 is used to purify exhaust gas discharged from the egr system 110, the cooler 115 is used to cool the recirculated exhaust gas, the throttle valve 116 is used to control gas introduced into the cylinder 100, and the air filter 117 is used to filter air introduced into the egr system 110. Exhaust gas generated by the cylinder 100 is subjected to noise reduction through a muffler 113 after passing through a catalyst 114 and then discharged outwards, meanwhile, part of the exhaust gas is cooled through a cooler 115 and then enters the cylinder 100 under the control of an exhaust gas recirculation valve 112, and meanwhile, when the engine runs, air is filtered through an air filter element 117 and then enters the cylinder 100 under the control of a throttle valve 116, so that exhaust gas recirculation is realized.

The controller 120 may be an Electronic Control Unit (ECU) including a processor 121 and a memory 122, where the memory 122 stores at least one instruction or program that is loaded and executed by the processor 121 to implement the method for detecting an exhaust gas recirculation system as provided by any of the method embodiments below.

The processor 121 may be a Central Processing Unit (CPU), a Network Processor (NP), or a combination of a CPU and an NP. The processor 121 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a Programmable Logic Device (PLD), or a combination thereof. The PLD may be a Complex Programmable Logic Device (CPLD), a field-programmable gate array (FPGA), a General Array Logic (GAL), or any combination thereof.

The memory 122 is connected to the processor 121 via a bus or other means, and at least one instruction, at least one program, code set or instruction set is stored in the memory 122, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by the processor 121 to implement the method for detecting an exhaust gas recirculation system according to any one of the method embodiments.

The memory 122 may be a volatile memory (volatile memory), a non-volatile memory (non-volatile memory), or a combination thereof. The volatile memory may be a random-access memory (RAM), such as a Static Random Access Memory (SRAM) or a Dynamic Random Access Memory (DRAM). The nonvolatile memory may be a Read Only Memory (ROM), such as a Programmable Read Only Memory (PROM), an Erasable Programmable Read Only Memory (EPROM), and an electrically erasable programmable read-only memory (EEPROM). The nonvolatile memory may also be a flash memory (flash memory), a magnetic memory such as a magnetic tape (magnetic tape), a floppy disk (floppy disk), and a hard disk. The non-volatile memory may also be an optical disc.

Referring to fig. 2, a flow chart of a method for detecting an exhaust gas recirculation system provided in an exemplary embodiment of the present application is shown, the method being applicable to the application environment provided in the embodiment of fig. 1, and the method including:

step 201, when the plug-in hybrid electric vehicle is in an idle pure charging working condition, an exhaust gas recirculation valve of an exhaust gas recirculation system is opened.

The controller can monitor the working condition state of the plug-in hybrid electric vehicle, and when the plug-in hybrid electric vehicle is determined to be in the idle pure charging working condition, the controller controls the waste gas recirculation valve of the waste gas recirculation system to be opened.

Step 202, a first pressure value is obtained, where the first pressure value is used to represent a pressure value of gas in the exhaust gas recirculation system at a first time, where the first time is a time when the exhaust gas recirculation valve is opened.

For example, at a first time when the controller controls the exhaust gas recirculation valve to open, a first pressure value may be collected by a pressure sensor disposed in the intake manifold, and the first pressure value may reflect the pressure of the gas entering the intake manifold at the first time.

A second pressure value is obtained, step 203, the second pressure value being indicative of a pressure value of the gas in the exhaust gas recirculation system at a second moment in time, the second moment in time being a first predetermined time period after the first moment in time.

For example, at a second time after the controller controls the exhaust gas recirculation valve to open for a first predetermined period of time, a second pressure value may be collected by a pressure sensor disposed in the intake manifold, and the first pressure value may reflect the pressure of the gas entering the intake manifold at the first time.

And 204, carrying out fault diagnosis on the exhaust gas recirculation system according to the difference value of the first pressure value and the second pressure value.

The applicant finds that when the plug-in hybrid electric vehicle is in an idle pure charging working condition, the engine has no other torque requirement, the engine is kept to operate at a certain constant rotating speed, the pressure of gas at the air inlet manifold does not fluctuate greatly, if the exhaust gas recirculation system has no fault, the gas can enter the air inlet manifold, the pressure removed by the air inlet manifold fluctuates in a certain range, and when the exhaust gas recirculation system is blocked to generate a low-flow fault, the gas cannot enter the air inlet manifold even if the exhaust gas recirculation valve is opened, and the fluctuation of the air inlet pressure cannot be caused.

In view of this, by obtaining a first air pressure at a first time point when the egr valve is opened and obtaining a second air pressure at a second time point after the first time point by a first predetermined time period, it is possible to determine whether or not the pressure of the gas entering the intake manifold fluctuates according to a difference between the first air pressure and the second air pressure at the first predetermined time period, and thus determine whether or not the egr system is clogged to cause a low flow rate failure. Since the pressure sensor is usually arranged in the intake manifold, an additional intake flow sensor does not need to be installed, and the detection cost is reduced.

As described above, in the embodiment of the present application, when the idle pure charging operation is performed, the exhaust gas recirculation valve of the exhaust gas recirculation system is opened for the first predetermined time period, and the fault diagnosis is performed on the exhaust gas recirculation system according to the pressure difference value of the gas entering the intake manifold in the first predetermined time period, so that the problem that the cost for determining the EGR flow rate is high by providing the intake flow sensor on the plug-in hybrid electric vehicle in the related art is solved, and the detection cost is reduced while the accuracy, the precision and the stability are high.

Referring to fig. 3, a flow chart of a method for detecting an exhaust gas recirculation system provided by an exemplary embodiment of the present application is shown, the method being applicable to the application environment provided in the embodiment of fig. 1, and the method may be another detection branch of the embodiment of fig. 2, and the method includes:

in step 301, when an engine of the plug-in hybrid electric vehicle is started, a third pressure value is obtained, wherein the third pressure value is a pressure value used for representing gas entering an air inlet manifold at a third moment after the engine is started.

For example, after the controller determines that the engine is started, a third pressure value may be collected at a third time by a pressure sensor disposed in the intake manifold, and the third pressure value may reflect a pressure of gas entering the intake manifold at the third time.

Step 302, a fourth pressure value is obtained, where the fourth pressure value is used to represent a pressure value of the gas entering the intake manifold at a fourth time, where the fourth time is a time that is a second predetermined time period after the third time.

For example, at a fourth time after a second predetermined period of time after the third time, a fourth pressure value may be collected by a pressure sensor provided in the intake manifold, and the fourth pressure value may reflect the pressure of the gas entering the intake manifold at the fourth time.

Step 303, obtaining the up-stroke of the engine speed in a second preset time period.

For example, the controller may obtain the engine speed from a local memory or other electronic controller in the plug-in hybrid vehicle to calculate the up-pulse of the engine speed for the second predetermined period.

And 304, carrying out fault diagnosis on the exhaust gas recirculation system according to the difference value between the fourth pressure value and the third pressure value and the upper impulse.

When the engine is started, the rotation speed is suddenly increased, and the pressure drop of the intake air pressure is large because the gas pressure of the intake manifold is greatly reduced due to the suction action of the piston. There are two conditions that result in a significant reduction in the pressure drop of the intake manifold gas pressure at engine start-up: (1) an inlet manifold leak tight, which appears to cause a post-throttle leak; (2) is blow-by of the exhaust gas recirculation system, which manifests itself as blow-by when the exhaust gas recirculation valve leaks, creating a high flow failure. However, these two blow-by engines behave quite differently: fresh air is introduced when the air is leaked from the air inlet manifold, the fresh air is rich in oxygen, namely the starting pre-control air inflow is increased, and the upward-flushing speed of the engine is increased when the engine is started; and the waste gas leaked through the waste gas recirculation valve is the waste gas after the combustion of the engine, and the waste gas basically has no oxygen and cannot participate in the combustion so that the rotating speed of the engine is greatly increased.

It can be seen that when the egr valve leaks to create a high flow fault, the intake manifold pressure drop is reduced and the engine speed is limited on start-up, even leading to engine stall, and there is no leakage in the engine intake system and significant inconsistency in intake manifold leakage.

In view of this, the third air pressure at the third time after the engine is started may be obtained, the fourth air pressure at the fourth time after the second predetermined time period after the third time may be obtained, and the difference between the third air pressure and the fourth air pressure may be obtained through calculation, where the difference may reflect the pressure drop of the intake manifold after the engine is started, and further, whether the exhaust gas recirculation system has a high flow rate fault may be determined according to the difference and the overshoot of the engine speed in the second predetermined time period. Because the pressure sensor is usually arranged in the intake manifold, the upward thrust of the engine speed can be calculated through engine speed data stored in an automobile, so that an additional intake flow sensor is not required to be installed, and the detection cost is reduced.

The applicant has found that the engine operating mode of the plug-in hybrid vehicle has the following characteristics with respect to the traditional pure fuel vehicle: (1) the idle speed of the engine is high and is usually over 1200 Revolutions Per Minute (RPM), while the idle speed of the engine heat engine of the pure fuel vehicle is only about 700 RPM, and the high idle speed means that the idle stability is good and the shock resistance is strong, and the idle speed of the plug-in hybrid electric vehicle is usually the pure charging condition when the battery electricity is insufficient, the engine does not directly drive the vehicle to run, even if the idle speed slightly fluctuates at the moment, the vehicle has no obvious abnormal performance and the user has no obvious perception; (2) the engine is always in the working conditions of reciprocating starting and stopping, and is electrically driven when the vehicle speed is low and the torque demand is small, and the engine does not work; when the battery is low or a large torque demand is suddenly made, the engine is started to work. In view of this, the embodiments of the present application are configured to detect when the vehicle is in an idle pure charge condition or when the engine is started.

Referring to fig. 4, a flow chart of a method for detecting an exhaust gas recirculation system provided in an exemplary embodiment of the present application is shown, the method being applicable to the application environment provided in the embodiment of fig. 1, and the method including:

step 401, determining whether the plug-in hybrid electric vehicle is in an idle pure charging working condition.

For example, the controller may monitor the operating condition state of the plug-in hybrid electric vehicle, and when it is determined that the plug-in hybrid electric vehicle is in the idle pure charging operating condition, the process proceeds to step 4021; if the plug-in hybrid electric vehicle is determined not to be in the idle pure charging condition, the process may proceed to step 401, or proceed to step 4022, or stop (the process of proceeding to step 4022 in fig. 4 is an exemplary description if the plug-in hybrid electric vehicle is determined not to be in the idle pure charging condition).

Step 4021, determining whether the water temperature of the engine of the plug-in hybrid electric vehicle is greater than a temperature threshold.

For example, the controller may obtain the water temperature of the engine from a local memory or other electronic controller in the plug-in hybrid vehicle, and when it is determined that the water temperature is greater than the temperature threshold a, go to step 4031; when it is determined that the water temperature is not greater than the temperature threshold a, step 401 may be entered, or step 4022 may be entered, or stopped (step 401 is illustratively entered when it is determined that the water temperature is not greater than the temperature threshold a in fig. 4).

The purpose of introducing the water temperature of the engine as a judgment condition is to avoid unstable combustion of mixed gas when the water temperature of the engine is low, and the active opening of the exhaust gas recirculation valve can cause large fluctuation of the rotating speed of the engine, so that judgment is influenced, and the detection accuracy is further improved.

4031, open the exhaust gas recirculation valve according to the target opening.

Wherein the target opening is less than 95% (e.g., it may be 10% to 75%).

The target opening degree B and the opening period T1 (i.e., the first predetermined period) are set in consideration of the actual performance of the engine, on the one hand, the inability to make a large fluctuation in the engine speed, and on the other hand, the distinction between the low flow rate failure and the no-failure state of the exhaust gas recirculation system is made conspicuous.

Step 4041, a first pressure value is obtained, where the first pressure value is acquired by a pressure sensor disposed in the intake manifold at a first time.

For example, at a first moment when the controller controls the opening of the egr valve, a first pressure value C may be collected by a pressure sensor provided in the intake manifold.

Step 4051, a second pressure value is obtained, where the second pressure value is acquired by a pressure sensor arranged in the intake manifold at a second time after the first time within a first predetermined time period.

For example, at a second time after the controller controls the exhaust gas recirculation valve to open for a first predetermined period of time (T1), a second pressure value D may be collected by a pressure sensor provided in the intake manifold.

Step 4061, a determination is made as to whether the difference between the first pressure value and the second pressure value is less than a difference threshold.

When it is determined that the difference (D-C) between the first pressure value C and the second pressure value D is less than the difference threshold E, proceeding to step 4071 b; when it is determined that the difference (D-C) between the first pressure value and the second pressure value is not less than the difference threshold E, step 4071a is entered.

Step 4071a, determining that the exhaust gas recirculation system does not have a low flow fault and the low flow fault detection is complete.

Step 4071b, determining that there is a low flow fault in the exhaust gas recirculation system, and reporting the low flow fault.

When a low flow fault is determined to exist, a low flow fault report may be performed. For example, the existence of the low-flow fault can be prompted through at least one of a video prompt, a voice prompt, an indicator light prompt and the like, and the corresponding fault code is stored.

Step 4022, determine whether the engine of the plug-in hybrid vehicle is started.

For example, the controller may monitor the operating condition status of the plug-in hybrid vehicle and, when it is determined that the engine is started, proceed to 4032; step 4022 may be entered when it is determined that the engine is not starting, or stopped (the stop step is exemplary in fig. 4 when it is determined that the engine is not starting).

4032, a third pressure value is obtained, which is acquired by a pressure sensor arranged in the intake manifold at a third moment after the engine is started.

For example, at a third time after the engine is started, a third pressure value E may be collected by a pressure sensor provided in the intake manifold.

Step 4042, a fourth pressure value is obtained, where the fourth pressure value is obtained by a pressure sensor arranged in the intake manifold at a fourth time after the third time and within a second predetermined time period.

Illustratively, the fourth pressure value F may be collected by a pressure sensor provided in the intake manifold at a fourth time that is a second predetermined time period (T2) after the third time.

Step 4052, an up-stroke of engine speed over a second predetermined period of time is obtained.

For example, the controller may obtain the engine speed from a local memory or other electronic controller in the plug-in hybrid vehicle, and calculate the upper limit G of the engine speed in the second predetermined time period T2.

Step 4062, it is determined whether the difference between the third pressure value and the fourth pressure value and the overshoot satisfy a trigger condition that the difference between the third pressure value and the fourth pressure value is smaller than the pressure drop threshold and the overshoot is smaller than the overshoot threshold.

For example, the controller determines whether the difference (E-F) between the third pressure value E and the fourth pressure value F is smaller than the pressure drop threshold K, and the overshoot G is smaller than the overshoot threshold M, and when it is determined that the difference (E-F) between the third pressure value E and the fourth pressure value F is smaller than the pressure drop threshold K and the overshoot G is smaller than the overshoot threshold M, the controller proceeds to step 4072 b; if none of the above is satisfied, the process proceeds to step 4072 a.

Step 4072a, increments the number of no faults by one.

Step 4082a, when the number of no-fault is greater than the second number threshold, determining that the exhaust gas recirculation system does not have a high-flow fault and the high-flow fault detection is complete.

The number of no faults N2 may be counted by setting a counter, and when the number of no faults N2 is greater than the second number threshold Q2, it is determined that the exhaust gas recirculation system does not have a high flow fault.

Step 4072b, increments the number of failures by one.

Step 4082b, when the number of faults is greater than the first number threshold, determining that a high flow fault exists in the exhaust gas recirculation system, and performing fault reporting.

The number of faults N1 may be counted by providing a counter, and when the number of faults N1 is greater than the first number threshold Q1, a high flow fault may be reported by determining that a high flow fault exists in the exhaust gas recirculation system. For example, the existence of the high-flow fault can be prompted through at least one of a video prompt, a voice prompt, an indicator light prompt and the like, and the corresponding fault code is stored.

Wherein Q1 may be equal to Q2; n1 may be equal to N2.

Referring to fig. 5, a block diagram of a detection device provided in an exemplary embodiment of the present application is shown, and the device may be implemented as a controller in any of the above embodiments through software, hardware or a combination of the two. The device includes: a control module 510, an acquisition module 520, and a processing module 530, wherein:

the control module 510 is configured to open an exhaust gas recirculation valve of an exhaust gas recirculation system when the plug-in hybrid vehicle is in an idle pure charging condition.

An obtaining module 520 configured to obtain a first pressure value, where the first pressure value is used to represent a pressure value of gas entering an intake manifold of an exhaust gas recirculation system at a first time, and the first time is a time when an exhaust gas recirculation valve is opened; and acquiring a second pressure value, wherein the second pressure value is used for representing the pressure value of the gas entering the air inlet manifold at a second moment, and the second moment is a moment which is a first preset time period after the first moment.

The processing module 530 is configured to perform fault diagnosis on the exhaust gas recirculation system according to a difference between the first pressure value and the second pressure value.

Optionally, the obtaining module 520 is further configured to obtain a first pressure value through a pressure sensor disposed in the intake manifold; and acquiring a second pressure value through the pressure sensor.

Optionally, the control module 510 is further configured to open an exhaust gas recirculation valve when the plug-in hybrid vehicle is in an idle pure charge condition and a water temperature of an engine of the plug-in hybrid vehicle is greater than a temperature threshold.

Optionally, the processing module 530 is further configured to determine that the exhaust gas recirculation system has a low flow fault when a difference between the first pressure value and the second pressure value is smaller than a difference threshold.

Optionally, the processing module 530 is further configured to determine that the exhaust gas recirculation system does not have the low flow fault when the difference between the first pressure value and the second pressure value is not less than the difference threshold.

Alternatively, when the egr valve of the egr system is opened, the opening of the egr valve is less than 95%.

Optionally, the obtaining module 520 is further configured to obtain a third pressure value when the engine of the plug-in hybrid electric vehicle is started, where the third pressure value is a pressure value representing a gas entering the intake manifold at a third time after the engine is started; acquiring a fourth pressure value, wherein the fourth pressure value is used for representing a pressure value of gas entering the intake manifold at a fourth moment, and the fourth moment is a moment which is a second preset time period after the third moment; and acquiring the up-pulse of the engine speed in a second preset time period.

Optionally, the processing module 530 is further configured to perform fault diagnosis on the exhaust gas recirculation system according to a difference between the fourth pressure value and the third pressure value and the upper impulse.

Optionally, the obtaining module 520 is further configured to obtain a third pressure value through a pressure sensor disposed in the intake manifold; a fourth pressure value is obtained by the pressure sensor.

Optionally, the processing module 530 is further configured to increase the number of faults by one when the difference between the third pressure value and the fourth pressure value and the overshoot meet a trigger condition, where the trigger condition is that the difference between the third pressure value and the fourth pressure value is smaller than the pressure drop threshold and the overshoot is smaller than the overshoot threshold; when the number of faults is greater than a first number threshold, it is determined that a high flow fault exists with the exhaust gas recirculation system.

Optionally, the processing module 530 is further configured to increase the number of non-faults by one when the difference between the third pressure value and the fourth pressure value and the overshoot do not satisfy the trigger condition; when the number of no-faults is greater than the second number threshold, it is determined that the exhaust gas recirculation system is free of high flow faults.

The present application further provides a computer readable storage medium having stored therein at least one instruction, at least one program, code set or set of instructions, which is loaded and executed by the processor to implement the method of detecting an exhaust gas recirculation system as described in any of the above embodiments.

The present application further provides a computer program product, which when run on a computer causes the computer to execute the method for detecting an exhaust gas recirculation system provided by the above-mentioned method embodiments.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of this invention are intended to be covered by the scope of the invention as expressed herein.