Egr system of engine, control method, and vehicle

Abstract

The application provides an EGR system, a control method and a vehicle of an engine. Based on the obtained engine working state, the opening degree of a set stop valve, an EGR bypass pipe and an EGR bypass valve is controlled, so that when the vehicle is in a low speed and low load working condition, the exhaust gas of the engine passes through the exhaust manifold 2, and under the action of the low opening degree of the stop valve and the EGR bypass valve, the gas pressure in the EGR passage and the EGR bypass pipe is increased, so that the gas is forced to flow to the air inlet end of the engine, thereby avoiding the defects that in the prior art, under the low speed and low load working condition, the gas in the pipeline cannot be circulated to the air inlet end of the engine through the pressure difference, and the aftertreatment system cannot reach the working temperature, and the working effect of the exhaust gas circulation and the aftertreatment system of the vehicle is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine exhaust gas circulation, and particularly relates to an EGR system of an engine, a control method and a vehicle. BACKGROUND

[0002] An EGR (exhaust gas recirculation) system is widely used in fuel vehicles as a solution to reduce vehicle exhaust pollution.

[0003] In the prior art, the EGR system drives gas through the difference between the pre-turbine pressure and the post-intercooler pressure. However, when the vehicle is in a low-speed and small-load working condition, the EGR system cannot effectively drive the gas in the pipeline. In addition, the cooling of the gas in the pipeline makes the engine exhaust low-temperature exhaust gas. However, the aftertreatment system in the EGR system needs to work based on high-temperature exhaust gas, and thus the working effect of the aftertreatment system is reduced.

[0004] Therefore, in the existing EGR system, the gas in the pipeline cannot be effectively driven, and the exhaust gas temperature is low, so that when the vehicle is in a small-load working condition, the exhaust gas circulation effect and the working effect of the aftertreatment system are poor. SUMMARY

[0005] The present application provides an EGR system of an engine, a control method and a vehicle, to solve the problem that the gas in the pipeline cannot be effectively driven, and the exhaust gas temperature is low, so that when the vehicle is in a small-load working condition, the exhaust gas circulation effect and the working effect of the aftertreatment system are poor.

[0006] In a first aspect, an EGR system of an engine is provided, comprising: an engine system, an EGR passage, a turbocharging passage and an aftertreatment system;

[0007] The engine system, the turbocharging passage and the engine system are sequentially connected by pipelines to form a turbo cycle loop.

[0008] The engine system, the EGR passage and the engine system are sequentially connected by pipelines to form an EGR cycle loop.

[0009] The engine system comprises an engine and an exhaust manifold connected by a pipeline.

[0010] The EGR passage is provided with an EGR cooler, an EGR bypass pipe and an EGR bypass valve. The EGR cooler and the EGR bypass pipe are arranged side by side, and the outlet of the EGR cooler and the outlet of the EGR bypass pipe are both connected to the EGR bypass valve.

[0011] The turbocharging passage is sequentially provided with a turbocharger, an intake intercooler;

[0012] A cut-off valve is arranged between the engine and the turbocharger in the turbo cycle loop;

[0013] The aftertreatment system is connected to the turbocharger through a pipeline for discharging the gas discharged by the turbocharger into the air after aftertreatment.

[0014] In a possible implementation, the cut-off valve is arranged on the exhaust manifold, or on the pipeline between the exhaust manifold and the turbocharger.

[0015] In a possible implementation, when the engine system has multiple exhaust manifolds, the cut-off valve is arranged on the exhaust manifold corresponding to the most cylinders.

[0016] In a possible implementation, a gas pressure sensor is further arranged between the exhaust manifold and the cut-off valve, and an exhaust temperature sensor is arranged between the aftertreatment system and the turbocharger.

[0017] The gas pressure sensor and the exhaust temperature sensor are both communicatively connected to an ECU.

[0018] In a possible implementation, the intake intercooler is respectively provided with a pre-intercooling temperature sensor and a post-intercooling temperature sensor before and after the turbocharging passage, the turbo cycle loop and the EGR cycle loop are provided with an intake temperature sensor on a common passage before the engine, and the EGR passage is further provided with an EGR temperature sensor after the EGR bypass valve.

[0019] The pre-intercooling temperature sensor, the post-intercooling temperature sensor, the intake temperature sensor, and the EGR temperature sensor are all communicatively connected to an ECU.

[0020] In a second aspect, an embodiment of the present application provides a control method of an EGR system of an engine, comprising:

[0021] Obtaining engine state information, the engine state information comprising at least one of the following information: a rotation speed and / or a torque;

[0022] Determining a working state of the engine according to the engine state information;

[0023] In the low load state and low speed state, the first opening degree control is performed on the stop valve and the EGR bypass valve, the first opening degree control including: reducing the opening degree of the stop valve to increase the gas pressure of the EGR passage, and reducing the opening degree of the EGR bypass valve to perform a first adjustment on the gas ratio of the EGR cooler and the EGR bypass pipe, the first adjustment including: reducing the gas passing through the EGR cooler and increasing the gas of the EGR bypass pipe;

[0024] In the high load state and / or high speed state, the second opening degree control is performed on the stop valve and the EGR bypass valve, the second opening degree control including: increasing the opening degree of the stop valve to reduce the gas pressure of the EGR passage, and increasing the opening degree of the EGR bypass valve to perform a second adjustment on the gas ratio of the EGR cooler and the EGR bypass pipe, the second adjustment including: increasing the gas passing through the EGR cooler and reducing the gas of the EGR bypass pipe.

[0025] In a possible implementation, the engine water temperature is acquired; if the water temperature is lower than a preset water temperature threshold, the first opening degree control is performed on the stop valve and the EGR bypass valve;

[0026] If the water temperature is higher than the preset water temperature threshold, the engine state information is acquired.

[0027] In a possible implementation, a gas pressure sensor is further arranged between the exhaust manifold and the stop valve, and is used to detect the input gas pressure of the EGR passage, and the reducing the opening degree of the stop valve includes:

[0028] When the input gas pressure is less than or equal to a preset gas pressure threshold, the opening degree of the stop valve is controlled to be reduced to a first opening degree, and the preset gas pressure threshold is the minimum gas pressure required to drive the gas in the EGR passage;

[0029] The increasing the opening degree of the stop valve includes:

[0030] When the input gas pressure is greater than the preset gas pressure threshold, the opening degree of the stop valve is controlled to be increased to a second opening degree, and the first opening degree is less than the second opening degree.

[0031] In a possible implementation, the reducing the opening degree of the stop valve to the first opening degree includes:

[0032] According to a gas pressure difference between the preset gas pressure threshold and the input gas pressure, a first adjustment amplitude of the stop valve is determined;

[0033] According to the first adjustment amplitude of the stop valve, the opening degree of the stop valve is controlled to be reduced to the first opening degree.

[0034] The control of the opening degree of the stop valve to increase to a second opening degree comprises:

[0035] According to a pressure difference between the input air pressure and the preset air pressure threshold, a second adjustment range of the stop valve is determined;

[0036] According to the second adjustment range of the stop valve, the opening degree of the stop valve is controlled to increase to a second opening degree.

[0037] In a possible implementation, an exhaust temperature sensor is arranged between the aftertreatment system and the turbocharger, and is configured to detect an exhaust temperature output by the turbocharger, and the decrease of the opening degree of the EGR bypass valve comprises:

[0038] The exhaust temperature output by the turbocharger is acquired;

[0039] If the exhaust temperature output by the turbocharger is less than or equal to the working temperature of the aftertreatment system, the EGR bypass valve is controlled to decrease to a third opening degree;

[0040] The increase of the opening degree of the EGR bypass valve comprises:

[0041] If the exhaust temperature output by the turbocharger is greater than the working temperature of the aftertreatment system, the EGR bypass valve is controlled to increase to a fourth opening degree, and the third opening degree is less than the fourth opening degree.

[0042] In a possible implementation, the control of the EGR bypass valve to decrease to a third opening degree comprises:

[0043] According to a first temperature difference between the working temperature of the aftertreatment system and the exhaust temperature, a first adjustment range of the EGR bypass valve is determined;

[0044] According to the first adjustment range of the EGR bypass valve, the EGR bypass valve is controlled to decrease to the third opening degree;

[0045] The control of the EGR bypass valve to increase to a fourth opening degree comprises:

[0046] According to a second temperature difference between the exhaust temperature and the working temperature of the aftertreatment system, a second adjustment range of the EGR bypass valve is determined;

[0047] According to the second adjustment range of the EGR bypass valve, the EGR bypass valve is controlled to increase to the fourth opening degree.

[0048] In a third aspect, an ECU is provided to implement the control method of the EGR system of the engine as described above.

[0049] In a fourth aspect, the embodiments of the present application provide a vehicle comprising the EGR system and the ECU of the engine as described above.

[0050] The EGR system of the engine, the control method and the vehicle provided by the embodiments of the present application are based on the acquired engine working state, and the opening degree control is performed on the set stop valve 3, the EGR bypass pipe 7 and the EGR bypass valve 8, so that when the vehicle is in the low speed and low load working condition, the gas discharged by the engine 1 passes through the exhaust manifold 2, and under the action of the low opening degree stop valve 3 and the EGR bypass valve 8, the gas pressure in the EGR passage and the EGR bypass pipe 7 is increased, so as to realize the forced gas flow to the air inlet end of the engine 1, thereby avoiding the defects that in the prior art, the gas in the pipeline cannot flow to the air inlet end of the engine 1 through the pressure difference under the low speed and low load working condition, and the aftertreatment system cannot reach the working temperature, and thereby the exhaust gas circulation of the vehicle and the working effect of the aftertreatment system are improved. BRIEF DESCRIPTION OF DRAWINGS

[0051] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments consistent with the present application and, together with the description, further serve to explain the principles of the application.

[0052] Figure 1 An existing EGR system schematic diagram provided by the present application;

[0053] Figure 2 An EGR system structure schematic diagram of the engine provided by the present application;

[0054] Figure 3 A control method flowchart of the EGR system of the engine provided by the present application Figure 1 ;

[0055] Figure 4 A control method flowchart of the EGR system of the engine provided by the present application Figure 2 ;

[0056] Figure 5 A running logic diagram provided by the present application;

[0057] Figure 6 A control method flowchart of the EGR system of the engine provided by the present application Figure 3 ;

[0058] Figure 7 A structure schematic diagram of an electronic device provided by the present application.

[0059] The specific embodiments of the application have been shown by way of example in the above figures, and will be described in greater detail below. These figures and this written description are not intended to limit the scope of the inventive concept in any way, but rather to illustrate the inventive concept to one of ordinary skill in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0060] Exemplary embodiments will be described in detail with reference to the drawings, wherein like reference numerals refer to like elements throughout. The following detailed description is not intended to limit the application, as claimed, in any way. Rather, it is described to provide those of ordinary skill in the art with a complete enabling description of the best mode of carrying out the application, and is intended to embody the application's aspects as set forth in the claims.

[0061] It should be noted that the user information (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in one or more embodiments of the present specification are all information and data authorized by the user or authorized by all parties, and the collection, use and processing of related data need to comply with relevant laws, regulations and standards, and provide corresponding operation portal for user to choose authorization or refusal.

[0062] It should be noted that in the embodiments of the present application, some software, components, models and other industry solutions may be mentioned, which should be considered as exemplary, and the purpose is only to illustrate the feasibility of the implementation of the technical solutions of the present application, but it does not mean that the applicant has or will necessarily use the solution.

[0063] In the existing exhaust treatment scheme of fuel vehicles, including SCR (Selective Catalyst Reduction) system and EGR (exhaust gas recirculation) system. The SCR system reacts the nitrogen oxides in the exhaust gas with the reducing agent through the action of the catalyst in the aftertreatment system to generate harmless nitrogen and water vapor, so as to achieve the purpose of reducing the emission of nitrogen oxides in the exhaust gas. However, with the continuous improvement of environmental protection and emission regulation requirements, only the aftertreatment system cannot meet the continuously improving requirements. Therefore, the EGR system is needed to treat the exhaust gas of fuel vehicles. Compared with the SCR system, the EGR system has a relatively simple aftertreatment system, but the combustion condition is relatively balanced.

[0064] Figure 1 The existing EGR system is shown in the figure, such as Figure 1As shown, the EGR system reduces the generation of nitrogen oxides in exhaust gas by returning part of the engine exhaust gas to the intake system to reduce the combustion temperature. The existing EGR system generally drives gas through the difference between the pre-turbine pressure and the post-intercooler pressure, but in the low speed and low load condition, due to turbocharging, the gas pressure in the pipeline where the turbocharger is located is greater than the gas pressure in the pipeline where the EGR cooler is located, so the gas in the pipeline where the EGR cooler is located can rarely return to the engine, thereby making it difficult for the EGR system to effectively achieve forced driving of the gas in the pipeline in the low speed and low load condition of the vehicle, i.e., the introduction of gas in the existing EGR system is difficult, resulting in poor exhaust gas circulation effect.

[0065] Meanwhile, in the existing EGR system, since the aftertreatment system needs to start working when the gas temperature reaches a preset working temperature, such as 180 degrees or above, the exhaust gas needs to be kept at a high temperature to reduce the emission of nitrogen oxides, but due to the cooling of the exhaust gas by the EGR cooler in the existing EGR system, the cooled exhaust gas is returned to the intake system, reducing the combustion temperature, so that the temperature of the exhaust gas discharged by the engine cannot reach the working temperature of the aftertreatment system, thereby reducing the processing amount of nitrogen oxides by the aftertreatment system, i.e., the working effect of the aftertreatment system in the existing EGR system is poor.

[0066] Analyzing the working process of the above-mentioned existing EGR system, the EGR system cannot effectively achieve forced driving of the gas in the pipeline in the low speed and low load condition of the vehicle; at the same time, due to the cooling of the exhaust gas by the cooler in the pipeline, the exhaust gas discharged by the engine has a low temperature, which cannot meet the requirement of the aftertreatment system to work normally based on high temperature. Therefore, in the existing EGR system, due to the inability to effectively drive the gas in the pipeline and avoid low exhaust gas temperature, the exhaust gas circulation effect and the working effect of the aftertreatment system are poor when the vehicle is in the low speed and low load condition, thereby making the combustion of the engine poor and unable to reduce the emission of nitrogen oxides in the exhaust gas.

[0067] Therefore, in view of the above, Figure 2 The EGR system structure diagram of the engine provided in the present application is shown in Figure 2 As shown, the present application provides an EGR system of an engine, comprising: an engine system, an EGR passage, a turbocharging passage and an aftertreatment system. Wherein, the engine system, the turbocharging passage and the engine system are connected in sequence by pipelines to form a turbocharging cycle loop; the engine system, the EGR passage and the engine system are connected in sequence by pipelines to form an EGR cycle loop.

[0068] The engine system comprises an engine 1 and an exhaust manifold 2 connected by a pipeline, and an EGR passage, wherein the EGR passage is provided with an EGR cooler 6, an EGR bypass pipe 7 and an EGR bypass valve 8, the EGR cooler 6 and the EGR bypass pipe 7 are arranged side by side, and the outlet of the EGR cooler 6 and the outlet of the EGR bypass pipe 7 are both connected to the EGR bypass valve 8.

[0069] The turbocharging passage is sequentially provided with a turbocharger and an intake intercooler 9, the turbocharger comprises a turbocharger turbine 4 and a turbocharger compressor 5, and the engine 1 and the turbocharger on the turbo cycle loop are provided with a stop valve 3.

[0070] Further, the stop valve 3 is located on the exhaust manifold 2 or on the pipeline between the exhaust manifold 2 and the turbocharger, when the engine system has multiple exhaust manifolds 2, the stop valve 3 is located on the exhaust manifold 2 corresponding to the most cylinders.

[0071] The aftertreatment system is connected to the turbocharger through a pipeline, for aftertreatment of the gas discharged by the turbocharger and then discharged into the air.

[0072] Further, a gas pressure sensor 14 is arranged between the exhaust manifold 2 and the stop valve 3, and an exhaust temperature sensor 15 is arranged between the aftertreatment system and the turbocharger, the gas pressure sensor 14 and the exhaust temperature sensor 15 are both communicatively connected to an ECU (Electronic Control Unit), wherein when the gas pressure obtained by the gas pressure sensor 14 is less than a preset gas pressure threshold, and the exhaust temperature obtained by the exhaust temperature sensor 15 is less than or equal to the working temperature of the aftertreatment system, it is confirmed that the working state of the engine 1 is caused by a low load state and a low speed state.

[0073] The intake intercooler 9 on the turbocharging passage is respectively provided with an intercooler front temperature sensor 10 and an intercooler rear temperature sensor 11 before and after, the turbo cycle loop and the EGR cycle loop are provided with an intake temperature sensor 12 on the common passage before the engine 1, and the EGR passage is further provided with an EGR temperature sensor 13 after the EGR bypass valve 8.

[0074] The intercooler front temperature sensor 10, the intercooler rear temperature sensor 11, the intake temperature sensor 12 and the EGR temperature sensor 13 are all communicatively connected to the ECU, so that the ECU can record the temperature data information sent by each temperature sensor, and the ECU controls the opening degree of the stop valve 3 and the EGR bypass valve 8 based on the recorded temperature data information.

[0075] Further, the EGR temperature sensor 13 can obtain the gas temperature after the EGR cooler 6 and the EGR bypass pipe 7 are regulated by the EGR bypass valve 8; the pre-intercooler temperature sensor 10 and the post-intercooler temperature sensor 11 can obtain the gas temperature before and after entering the intake air intercooler 9; and the intake air temperature sensor 12 can detect the gas temperature before entering the intake end of the engine 1.

[0076] The EGR system of the engine provided in the application can realize that when the vehicle is in a low-speed and low-load working condition, the gas discharged from the engine 1 passes through the exhaust manifold 2 and, under the action of the low-opening stop valve 3, enters the pipeline in which the turbocharger is located in a small amount, and enters the pipeline in which the EGR cooler 6 and the EGR bypass pipe 7 are located in a large amount, thereby realizing the forced gas flow to the intake end of the engine 1, and avoiding the defect that in the prior art, the gas in the pipeline cannot flow to the intake end of the engine 1 through the pressure difference under the low-speed and low-load working condition, and thereby improving the exhaust gas circulation working effect when the vehicle is in the low-speed and low-load working condition.

[0077] The EGR system of the engine provided in the application can realize that when the vehicle is in a low-speed and low-load working condition, the gas discharged from the engine 1 passes through the exhaust manifold 2 and, under the action of the low-opening stop valve 3, enters the pipeline in which the turbocharger is located in a small amount, and enters the pipeline in which the EGR cooler 6 and the EGR bypass pipe 7 are located in a large amount, thereby realizing the forced gas flow to the intake end of the engine 1, and avoiding the defect that in the prior art, the gas in the pipeline cannot flow to the intake end of the engine 1 through the pressure difference under the low-speed and low-load working condition, and thereby improving the exhaust gas circulation working effect when the vehicle is in the low-speed and low-load working condition.

[0078] The technical solutions of the application and how the technical solutions of the application solve the above technical problems will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described again in some embodiments. The embodiments of the application will be described below with reference to the drawings.

[0079] Based on the above-mentioned EGR system structure of the engine, Figure 3 The control method flow of the EGR system of the engine provided in the application Figure 1 , combinedFigure 2 and Figure 3 The method comprises:

[0080] S101, acquiring engine state information, the engine state information comprising at least one of the following information: rotation speed and / or torque.

[0081] Specifically, the current vehicle state is detected, and it is indicated by the current vehicle state whether the vehicle is started normally. When the vehicle is started normally, the engine water temperature is caused to rise, and thus the engine water temperature is acquired by the ECU, and it is confirmed according to the engine water temperature whether the vehicle is cold started.

[0082] Further, when the vehicle is cold started, the ECU controls the cut-off valve 3 and the EGR bypass valve 8 to each preset opening degree, and when the vehicle is not cold started, the current rotation speed and torque of the engine are continuously acquired by the ECU and used as the engine state information.

[0083] S102, determining the working state of the engine according to the engine state information.

[0084] Specifically, when the vehicle is not cold started and the engine state information is acquired, the corresponding working state is determined according to the rotation speed and torque in the engine state information. When the rotation speed is low, it indicates that the engine works in a low-speed state, and when the torque is low, it indicates that the engine works in a low-load state. Therefore, the working state of the engine includes a low-load and low-speed state, a high-load state and / or a high-speed state.

[0085] S103, when the working state is a low-load and low-speed state, performing first opening degree control on the cut-off valve and the EGR bypass valve, the first opening degree control comprising: reducing the opening degree of the cut-off valve to increase the gas pressure of the EGR passage, and reducing the opening degree of the EGR bypass valve to perform first adjustment on the gas proportion of the EGR cooler and the EGR bypass pipe, the first adjustment comprising: reducing the gas passing through the EGR cooler and increasing the gas of the EGR bypass pipe.

[0086] Specifically, after the working state of the engine 1 is determined according to the engine state information, when the working state of the engine 1 is a low-load and low-speed state, the gas discharged by the engine 1 passes through the exhaust manifold 2, and due to the reduction of the opening degree of the cut-off valve 3, that is, under the action of the low-opening cut-off valve 3, most of the gas passing through the exhaust manifold 2 enters the EGR passage, that is, the gas pressure of the EGR passage is increased, thereby avoiding the situation that under the low-rotation and low-load working condition, due to the insufficient pressure between the engine 1 and the exhaust manifold 2, the gas cannot circulate in the pipeline to the intake end of the engine 1.

[0087] Further, for the gas entering the EGR passage, in the EGR passage, by controlling the opening degree of the EGR bypass valve, so that under the action of the low opening degree EGR bypass valve 8, the gas in the EGR passage, most of which passes through the EGR bypass pipe 7, and a small part of which passes through the EGR cooler 6, that is, the first adjustment of the gas ratio of the EGR cooler 6 and the EGR bypass pipe 7 is realized, thereby avoiding the situation that under the low speed and low load working condition, due to the cooling of the gas by the EGR cooler 6, the temperature of the gas discharged from the engine 1 is not high, so that the aftertreatment system cannot reach the working temperature, and the aftertreatment system cannot work normally.

[0088] S104、In the case that the working state is a high load state and / or a high speed state, the second opening degree control is performed on the stop valve and the EGR bypass valve, the second opening degree control comprising: increasing the opening degree of the stop valve to reduce the gas pressure in the EGR passage, and increasing the opening degree of the EGR bypass valve to perform the second adjustment of the gas ratio of the EGR cooler and the EGR bypass pipe, the second adjustment comprising: increasing the gas passing through the EGR cooler and reducing the gas in the EGR bypass pipe.

[0089] Specifically, when the working state of the engine 1 is not a low load state and a low speed state, that is, the working state of the engine 1 is a high load state and / or a high speed state, the gas discharged from the engine 1 passes through the exhaust manifold 2, and under the action of the high opening degree stop valve 3, the gas passing through the exhaust manifold 2 enters the EGR passage and the turbo passage, at this time, under the high load state and / or high speed state working condition, the pressure between the engine 1 and the exhaust manifold 2 can make the gas circulate in the pipeline to the intake end of the engine 1.

[0090] Further, for the gas entering the EGR passage, in the EGR passage, by controlling the opening degree of the EGR bypass valve, so that under the action of the high opening degree EGR bypass valve, the gas in the EGR passage, most of which passes through the EGR cooler, and a small part of which passes through the EGR bypass pipe 7, because under the high load state and / or high speed state, the temperature of the gas discharged from the engine 1 meets the working temperature of the aftertreatment system.

[0091] The control method for the EGR system of the engine provided in this application embodiment, based on the engine's operating state, controls the opening degree of the set shut-off valve 3, EGR bypass pipe 7, and EGR bypass valve 8. This enables the gas discharged from the engine 1 to increase the gas pressure in the EGR passage and EGR bypass pipe 7 under the action of the low-opening shut-off valve 3 and EGR bypass valve 8 after passing through the exhaust manifold 2 when the vehicle is in a low-speed, low-load condition. This forces the gas to flow to the intake end of the engine 1, thereby avoiding the shortcomings of existing solutions where the gas in the pipeline cannot circulate to the intake end of the engine 1 due to the pressure difference, and the aftertreatment system fails to reach the operating temperature. This improves the working effect of the vehicle's exhaust gas recirculation and aftertreatment system.

[0092] Figure 4 Flowchart of the control method for the EGR system of the engine provided in this application Figure 2 , Figure 5 The operational logic diagram provided for this application, combined with Figure 4 and Figure 5 As shown, in this embodiment... Figure 2 Based on the embodiments, the control method of the engine's EGR system is described in detail, and the method includes:

[0093] S201, Obtain engine coolant temperature.

[0094] Specifically, the engine coolant temperature is collected by the ECU, and it is detected whether the engine coolant temperature is lower than the preset coolant temperature threshold. The detection results are obtained, and the vehicle is confirmed to have been cold-started based on the detection results.

[0095] S202. If the water temperature is lower than the preset water temperature threshold, the first opening degree control is applied to the shut-off valve and the EGR bypass valve.

[0096] If the test result indicates that the water temperature is lower than the preset water temperature threshold, confirming that the vehicle is in a cold start, the opening of the shut-off valve 3 is reduced to the preset cold start shut-off opening, so that the gas pressure in the EGR passage increases to the preset cold start gas pressure, and the opening of the EGR bypass valve 8 is reduced to the preset cold start bypass opening, so that the gas pressure passing through the EGR cooler 6 reaches the preset cooling target gas pressure, and the gas pressure in the EGR bypass pipe 7 reaches the preset bypass target gas pressure, wherein the preset bypass target gas pressure is greater than the preset cooling target gas pressure.

[0097] S203. If the water temperature is higher than the preset water temperature threshold, then obtain the engine status information.

[0098] Specifically, if the detection result indicates that the water temperature is higher than the preset water temperature threshold and the vehicle is not cold started, the corresponding working state is determined according to the engine state information, so that the ECU can determine the corresponding working state according to the engine state information, and control the opening degree of the cut-off valve 3 and the EGR bypass valve 8 based on different working states.

[0099] S204, determine the working state of the engine according to the engine state information.

[0100] Specifically, the content of this step is the same as that of S102, which will not be repeated here.

[0101] S205, when the working state is a low load state and a low speed state, detecting the input air pressure of the EGR passage.

[0102] Specifically, before determining the working state of the engine according to the engine state information, the input air pressure of the EGR passage is collected by the air pressure sensor arranged between the exhaust manifold 2 and the cut-off valve 3, and the opening degree of the cut-off valve 3 is controlled according to the collected input air pressure and the working state.

[0103] S206, when the input air pressure is less than or equal to a preset air pressure threshold, the opening degree of the cut-off valve is controlled to decrease to a first opening degree, and the preset air pressure threshold is the minimum air pressure required to drive the gas in the EGR passage.

[0104] Specifically, after obtaining the input air pressure through the air pressure sensor, it is detected that the input air pressure is less than or equal to the preset air pressure threshold, and when the working state of the engine 1 is a low load state and a low speed state, it is determined that because the engine is in a low load state and a low speed state, the gas discharged by the engine 1 after passing through the exhaust manifold 2 has a small air pressure difference between the exhaust manifold 2 and the cut-off valve 3, and cannot realize the circulation of the gas in the pipeline to the intake end of the engine 1, so the opening degree of the cut-off valve 3 is controlled to decrease to a first opening degree.

[0105] Further, when the opening degree of the cut-off valve 3 is controlled to decrease to the first opening degree, the first adjustment amplitude of the cut-off valve is determined in the air pressure opening degree adjustment corresponding table according to the air pressure difference between the preset air pressure threshold and the input air pressure, and the opening degree of the cut-off valve is controlled to decrease to the first opening degree according to the first adjustment amplitude of the cut-off valve, wherein the air pressure opening degree adjustment corresponding table pre-stores the corresponding relationship between the air pressure difference and the adjustment amplitude, and the air pressure difference and the adjustment amplitude are positively correlated.

[0106] Further, of course, the gas flow into the EGR passage and the turbocharged passage can be controlled by controlling the opening degree of the cut-off valve 3.

[0107] S207, obtaining the exhaust temperature output by the turbocharger, and if the exhaust temperature output by the turbocharger is less than or equal to the working temperature of the aftertreatment system, controlling the EGR bypass valve to reduce to a third opening degree.

[0108] Specifically, the exhaust temperature output by the turbocharger is obtained by an exhaust temperature sensor arranged between the aftertreatment system and the turbocharger, and if the exhaust temperature output by the turbocharger is less than or equal to the working temperature of the aftertreatment system, such as 180 degrees, and when the working state of the engine 1 is in a low load state and a low speed state, it is determined that the temperature of the gas discharged by the engine 1 after passing through the exhaust manifold 2 is low, so that the working temperature of the aftertreatment system cannot be met, due to the engine being in a low load state and a low speed state.

[0109] Therefore, according to the first temperature difference between the working temperature of the aftertreatment system and the exhaust temperature, the first adjustment amplitude of the EGR bypass valve is determined in the temperature opening degree adjustment corresponding table, and the EGR bypass valve is controlled to reduce to a third opening degree according to the first adjustment amplitude of the EGR bypass valve.

[0110] The temperature difference and the adjustment amplitude are positively correlated, the working temperature of the aftertreatment system is less than the exhaust temperature, that is, the working temperature of the aftertreatment system is less than the gas temperature output by the turbocharger.

[0111] Further, of course, the gas flow control output in the EGR cooler 6 and the EGR bypass pipe 7 can also be realized by controlling the opening degree of the EGR bypass valve 8, and then the gas of different temperature flowing into the intake end of the engine 1 is controlled.

[0112] The control method of the EGR system of the engine provided by the embodiment of the application is based on the working state of the engine, and the opening degree of the arranged cut-off valve 3, the EGR bypass pipe 7 and the EGR bypass valve 8 is controlled, so that when the vehicle is in a low speed and low load working condition, the gas discharged by the engine 1 after passing through the exhaust manifold 2 is increased in pressure in the EGR bypass pipe 7 and the EGR bypass pipe 7 under the action of the low opening degree cut-off valve 3 and the EGR bypass valve 8, so that the gas is forced to flow to the intake end of the engine 1, thereby avoiding the defects that the gas in the pipeline cannot flow to the intake end of the engine 1 by the pressure difference in the prior art when the vehicle is in a low speed and low load working condition, and the working temperature of the aftertreatment system cannot be reached, thereby improving the exhaust gas circulation of the vehicle and the working effect of the aftertreatment system.

[0113] Figure 6 The control method of the EGR system of the engine provided by the embodiment of the application is based on the working state of the engine, and the opening degree of the arranged cut-off valve 3, the EGR bypass pipe 7 and the EGR bypass valve 8 is controlled, so that when the vehicle is in a low speed and low load working condition, the gas discharged by the engine 1 after passing through the exhaust manifold 2 is increased in pressure in the EGR bypass pipe 7 and the EGR bypass pipe 7 under the action of the low opening degree cut-off valve 3 and the EGR bypass valve 8, so that the gas is forced to flow to the intake end of the engine 1, thereby avoiding the defects that the gas in the pipeline cannot flow to the intake end of the engine 1 by the pressure difference in the prior art when the vehicle is in a low speed and low load working condition, and the working temperature of the aftertreatment system cannot be reached, thereby improving the exhaust gas circulation of the vehicle and the working effect of the aftertreatment system. Figure 3 As shown in the control method of the EGR system of the engine provided by the embodiment of the application is based on the working state of the engine, and the opening degree of the arranged cut-off valve 3, the EGR bypass pipe 7 and the EGR bypass valve 8 is controlled, so that when the vehicle is in a low speed and low load working condition, the gas discharged by the engine 1 after passing through the exhaust manifold 2 is increased in pressure in the EGR bypass pipe 7 and the EGR bypass pipe 7 under the action of the low opening degree cut-off valve 3 and the EGR bypass valve 8, so that the gas is forced to flow to the intake end of the engine 1, thereby avoiding the defects that the gas in the pipeline cannot flow to the intake end of the engine 1 by the pressure difference in the prior art when the vehicle is in a low speed and low load working condition, and the working temperature of the aftertreatment system cannot be reached, thereby improving the exhaust gas circulation of the vehicle and the working effect of the aftertreatment system. Figure 6 Figure 3 ​The control method of the EGR system of the engine is described in detail based on the embodiment, which comprises:

[0114] S301, detecting the input air pressure of the EGR passage when the working state of the engine is in the high load state and / or the high speed state.

[0115] Specifically, the input air pressure of the EGR passage and the exhaust temperature output by the turbocharger are collected by the air pressure sensor arranged between the exhaust manifold 2 and the cut-off valve 3, and the exhaust temperature sensor between the aftertreatment system and the turbocharger. The opening degree of the cut-off valve 3 is controlled according to the input air pressure and the working state, and the opening degree of the EGR bypass valve 8 is controlled according to the exhaust temperature and the working state.

[0116] S302, when the input air pressure is greater than the preset air pressure threshold, the opening degree of the cut-off valve is controlled to increase to the second opening degree, and the first opening degree is less than the second opening degree.

[0117] Specifically, when it is detected that the input air pressure is greater than the preset air pressure threshold, and when the working state of the engine 1 is in the high load state and / or the high speed state, it is determined that the situation that the gas cannot be circulated to the intake end of the engine 1 due to the working state of the engine 1 being in the low load state and the low speed state does not occur, and therefore the opening degree of the cut-off valve 3 is controlled to decrease to the second opening degree, so that the gas discharged by the engine 1 can be evenly passed through the EGR passage and the turbocharging passage through the exhaust manifold 2.

[0118] Further, for controlling the opening degree of the cut-off valve 3 to decrease to the second opening degree, according to the air pressure difference between the input air pressure and the preset air pressure threshold, the second adjustment amplitude of the cut-off valve 3 is determined in the air pressure opening degree adjustment corresponding table, and according to the second adjustment amplitude of the cut-off valve 3, the opening degree of the cut-off valve 3 is controlled to increase to the second opening degree, wherein the air pressure opening degree adjustment corresponding table prestores the corresponding relationship between the air pressure difference and the adjustment amplitude.

[0119] Further, of course, the gas flow control into the EGR passage and the turbocharging passage can be realized by controlling the size of the opening degree of the cut-off valve 3.

[0120] S303, obtaining the exhaust temperature output by the turbocharger, and if the exhaust temperature output by the turbocharger is greater than the working temperature of the aftertreatment system, controlling the EGR bypass valve to increase to the fourth opening degree, and the third opening degree is less than the fourth opening degree.

[0121] Specifically, when the exhaust temperature of the turbocharger output is greater than the working temperature of the aftertreatment system, and when the working state of the engine 1 is in a high load state and / or a high speed state, it is determined that the EGR cooler 6 does not cause the gas to be cooled, so that the aftertreatment system cannot meet the working temperature condition when the working state of the engine 1 is in a low load state and a low speed state, and therefore the EGR bypass valve 8 is controlled to increase to the fourth opening degree, so that the gas can pass through the EGR cooler 6 and the EGR bypass pipe 7.

[0122] Further, for controlling the EGR bypass valve 8 to increase to the fourth opening degree, according to the second temperature difference between the exhaust temperature and the working temperature of the aftertreatment system, the second adjustment amplitude of the EGR bypass valve 8 is determined in the temperature opening degree adjustment corresponding table, and the EGR bypass valve 8 is controlled to increase to the fourth opening degree according to the second adjustment amplitude of the EGR bypass valve.

[0123] Further, of course, the flow control of the gas output in the EGR cooler 6 and the EGR bypass pipe 7 can also be realized by controlling the opening degree of the EGR bypass valve 8, and then the different temperature control of the gas flowing into the intake end of the engine 1 can be realized.

[0124] The control method of the EGR system of the engine provided in the embodiment of the application is based on the working state of the engine, and the opening degree control of the set cut-off valve 3, the EGR bypass pipe 7 and the EGR bypass valve 8 is performed, so that when the vehicle is in a low speed and low load working condition, the gas discharged from the engine 1 passes through the exhaust manifold 2, and under the action of the low opening degree cut-off valve 3 and the EGR bypass valve 8, the gas pressure in the EGR passage and the EGR bypass pipe 7 is increased, so that the gas is forced to flow to the intake end of the engine 1, thereby avoiding the defects that in the prior art, the gas in the pipeline cannot be circulated to the intake end of the engine 1 by the pressure difference, and the working temperature of the aftertreatment system cannot be reached when the vehicle is in a low speed and low load working condition, and the working effect of the exhaust gas circulation and the aftertreatment system of the vehicle is improved.

[0125] The application also provides an ECU for realizing the control method of the EGR system of the engine.

[0126] The application also provides a vehicle comprising the ECU and the EGR system.

[0127] Figure 7 The structure schematic diagram of the electronic device provided in the application is shown in the figure. Figure 7 As shown in the figure, the electronic device 70 provided in the embodiment comprises at least one processor 701 and a memory 702. Optionally, the device 70 further comprises a communication component 703. The processor 701, the memory 702 and the communication component 703 are connected through a bus 704.

[0128] In the implementation process, the at least one processor 701 executes the computer-executable instructions stored in the memory 702, so that the at least one processor 701 executes the method described above.

[0129] The implementation process of the processor 701 can refer to the method embodiments described above, which have similar implementation principles and technical effects, and details are not described here.

[0130] In the above embodiments, it should be understood that the processor can be a central processing unit (English: Central Processing Unit, CPU for short), and can also be other general-purpose processors, digital signal processors (English: Digital Signal Processor, DSP for short), application specific integrated circuits (English: Application Specific Integrated Circuit, ASIC for short), etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the application can be directly embodied as hardware processor execution or combined with hardware and software modules in the processor for execution.

[0131] The memory can include a random access memory (RAM), and can also include a non-volatile memory (NVM), such as at least one disk memory.

[0132] The bus can be an industry standard architecture (ISA) bus, a peripheral component (PCI) bus, or an extended industry standard architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, the bus in the drawings of the present application does not limit only one bus or one type of bus.

[0133] The present application also provides a computer program product, comprising a computer program, which is executed by a processor to implement the method described above.

[0134] The present application also provides a computer-readable storage medium, which stores computer-executable instructions, and when the processor executes the computer-executable instructions, the method described above is implemented.

[0135] The above-mentioned readable storage medium can be realized by any type of volatile or nonvolatile storage devices or their combinations, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general or special purpose computer.

[0136] An exemplary readable storage medium is coupled to the processor, so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be an integral part of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in the device.

[0137] The division of units is only a logical function division, and in actual implementation, there can be another division manner, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0138] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on multiple network units. According to actual needs, part or all of the units can be selected to achieve the purpose of the embodiment scheme.

[0139] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit.

[0140] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts of the technical solutions that essentially contribute to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the embodiments of the method of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0141] It can be understood by those skilled in the art that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware. The aforementioned program can be stored in a computer readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, and various media that can store program codes.

[0142] Finally, it should be noted that: those skilled in the art will easily think of other embodiments of the present application after considering the specification and practicing the application disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application that follow the general principles of the present application and include common knowledge or conventional technical means in the art that are not disclosed in the present application, and is not limited to the precise structure described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is only limited by the appended claims.

Claims

1. A control method of an EGR system of an engine, characterized by, The EGR system comprises an engine system, an EGR passage, a turbocharging passage and an aftertreatment system; The engine system, the turbocharging passage and the engine system are sequentially connected by pipelines to form a turbo cycle loop; The engine system, the EGR passage and the engine system are sequentially connected by pipelines to form an EGR cycle loop; The engine system comprises an engine and an exhaust manifold connected by a pipeline; The EGR passage is provided with an EGR cooler, an EGR bypass pipe and an EGR bypass valve, the EGR cooler and the EGR bypass pipe are arranged side by side, and the outlet of the EGR cooler and the outlet of the EGR bypass pipe are both connected to the EGR bypass valve; The turbocharging passage is sequentially provided with a turbocharger and an intake intercooler; A shut-off valve is arranged between the engine and the turbocharger in the turbo cycle loop; The aftertreatment system is connected to the turbocharger by a pipeline, for aftertreatment of the gas discharged by the turbocharger before being discharged into the air; Engine state information is acquired, the engine state information comprising at least one of the following: engine speed and / or torque; The working state of the engine is determined according to the engine state information; When the working state is a low load state and a low speed state, the shut-off valve and the EGR bypass valve are controlled at a first opening degree, the first opening degree control comprising: reducing the opening degree of the shut-off valve to increase the gas pressure in the EGR passage, and reducing the opening degree of the EGR bypass valve to make a first adjustment to the gas ratio of the EGR cooler and the EGR bypass pipe, the first adjustment comprising: reducing the gas passing through the EGR cooler and increasing the gas in the EGR bypass pipe; When the working state is a high load state and / or a high speed state, the shut-off valve and the EGR bypass valve are controlled at a second opening degree, the second opening degree control comprising: increasing the opening degree of the shut-off valve to reduce the gas pressure in the EGR passage, and increasing the opening degree of the EGR bypass valve to make a second adjustment to the gas ratio of the EGR cooler and the EGR bypass pipe, the second adjustment comprising: increasing the gas passing through the EGR cooler and reducing the gas in the EGR bypass pipe.

2. The method of claim 1, wherein, The shut-off valve is located on the exhaust manifold, or on the pipeline between the exhaust manifold and the turbocharger.

3. The method of claim 2, wherein, When the engine system has multiple exhaust manifolds, the shut-off valve is located on the exhaust manifold corresponding to the most cylinders.

4. The method according to any one of claims 1 to 3, characterized in that, A gas pressure sensor is further arranged between the exhaust manifold and the shut-off valve, and an exhaust temperature sensor is arranged between the aftertreatment system and the turbocharger; The gas pressure sensor and the exhaust temperature sensor are both communicatively connected to an ECU.

5. The method of claim 4, wherein, The intercooler before and after the turbocharged passage is respectively provided with an intercooling before temperature sensor and an intercooling after temperature sensor, the turbo cycle loop and the EGR cycle loop are provided with an intake temperature sensor on the common passage before the engine, and the EGR passage is further provided with an EGR temperature sensor after the EGR bypass valve; The intercooling before temperature sensor, the intercooling after temperature sensor, the intake temperature sensor and the EGR temperature sensor are all in communication connection with an ECU.

6. The method of claim 1, wherein, The engine state information is acquired, including: Acquiring an engine water temperature; If the water temperature is lower than a preset water temperature threshold, performing first opening degree control on the cut-off valve and the EGR bypass valve; If the water temperature is higher than the preset water temperature threshold, acquiring engine state information.

7. The method according to claim 1 or 6, characterized in that, The exhaust manifold and the cut-off valve are further provided with a gas pressure sensor for detecting the input gas pressure of the EGR passage, and the opening degree of the cut-off valve is reduced, including: When the input gas pressure is less than or equal to a preset gas pressure threshold, the opening degree of the cut-off valve is controlled to be reduced to a first opening degree, and the preset gas pressure threshold is the minimum gas pressure required to drive the gas in the EGR passage; The opening degree of the cut-off valve is increased, including: When the input gas pressure is greater than the preset gas pressure threshold, the opening degree of the cut-off valve is controlled to be increased to a second opening degree, and the first opening degree is less than the second opening degree.

8. The method of claim 7, wherein, The opening degree of the cut-off valve is controlled to be reduced to a first opening degree, including: According to the gas pressure difference between the preset gas pressure threshold and the input gas pressure, a first adjustment amplitude of the cut-off valve is determined; According to the first adjustment amplitude of the cut-off valve, the opening degree of the cut-off valve is controlled to be reduced to a first opening degree; The opening degree of the cut-off valve is controlled to be increased to a second opening degree, including: According to the gas pressure difference between the input gas pressure and the preset gas pressure threshold, a second adjustment amplitude of the cut-off valve is determined; According to the second adjustment amplitude of the cut-off valve, the opening degree of the cut-off valve is controlled to be increased to a second opening degree.

9. The method of claim 1 or 6, wherein, An exhaust temperature sensor is arranged between the aftertreatment system and the turbocharger for detecting the exhaust temperature output by the turbocharger, the opening degree of the EGR bypass valve is reduced, including: The exhaust temperature output by the turbocharger is acquired; If the exhaust temperature output by the turbocharger is less than or equal to the working temperature of the aftertreatment system, the EGR bypass valve is controlled to be reduced to a third opening degree; The opening degree of the EGR bypass valve is increased, including: If the exhaust temperature output by the turbocharger is greater than the working temperature of the aftertreatment system, the EGR bypass valve is controlled to be increased to a fourth opening degree, and the third opening degree is less than the fourth opening degree.

10. The method of claim 9, wherein, The EGR bypass valve is controlled to be reduced to a third opening degree, including: According to a first temperature difference between the working temperature of the aftertreatment system and the exhaust temperature, a first adjustment amplitude of the EGR bypass valve is determined; According to the first adjustment amplitude of the EGR bypass valve, the EGR bypass valve is controlled to be reduced to the third opening degree; The EGR bypass valve is controlled to be increased to a fourth opening degree, including: determining a second adjustment range of the EGR bypass valve according to a second temperature difference between the exhaust gas temperature and an operating temperature of the aftertreatment system; controlling the EGR bypass valve to increase to the fourth opening degree according to the second adjustment range of the EGR bypass valve.

11. An ECU characterized by comprising: A computer program product for performing the method of any one of claims 1 to 10.

12. A vehicle characterized by comprising: An ECU comprising the ECU of claim 11.

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