EGR system of engine, control method and vehicle

Abstract

According to the EGR system of the engine, the control method and the vehicle, based on the obtained working state of the engine, opening control is conducted on the arranged stop valve, the EGR bypass pipe and the EGR bypass valve, and when the vehicle is in the low-rotating-speed and low-load working condition, after gas exhausted by the engine passes through the exhaust manifold 2, under the action of the low-opening-degree stop valve and the EGR bypass valve, the gas exhausted by the engine is exhausted through the exhaust manifold 2; the air pressure in the EGR passage and the EGR bypass pipe is increased, so that the air is forced to flow to the air inlet end of the engine, and the defects that the air in the pipeline cannot circularly flow to the air inlet end of the engine through the air pressure difference value and the post-processing system cannot reach the working temperature in the low-rotating-speed and low-load working condition in the existing scheme are overcome; therefore, the working effects of the exhaust gas circulation and post-treatment system of the vehicle are improved.

Description

Technical Field

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

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

[0003] In the prior art, the EGR system drives the gas through the difference between the pressure before the turbine and the pressure after the intercooler. However, when the vehicle is in a low-speed and low-load condition, the gas in the pipeline cannot be effectively driven. At the same time, due to the cooling of the gas in the pipeline, the engine discharges exhaust gas with a lower temperature, and the after-treatment system in the EGR system needs to work normally based on the high-temperature exhaust gas, thereby reducing the working effect of the after-treatment system.

[0004] Therefore, in the existing EGR system, since it is impossible 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 post-treatment system are poor when the vehicle is in a low load condition. Summary of the invention

[0005] The present application provides an EGR system, a control method and a vehicle of an engine, so as to solve the defect that the exhaust gas circulation effect and the working effect of the post-treatment system are poor when the vehicle is in a low-load condition due to the inability to drive the gas in the pipeline and avoid low exhaust gas temperature.

[0006] In a first aspect, an embodiment of the present application provides an EGR system of an engine, comprising: an engine system, an EGR passage, a turbocharger passage, and a post-treatment system;

[0007] Wherein, the engine system, the turbocharging passage, and the engine system are sequentially connected through pipelines to form a turbine circulation loop;

[0008] The engine system, the EGR passage, and the engine system are sequentially connected through pipelines to form an EGR circulation loop;

[0009] The engine system includes 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 in parallel, 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 turbocharger passage is provided with: a turbocharger and an air intake intercooler in sequence;

[0012] A shutoff valve is provided between the engine and the turbocharger on the turbine circulation loop;

[0013] The aftertreatment system is connected to the turbocharger through a pipeline, and is used for after-treating the gas exhausted by the turbocharger and then discharging it into the air.

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

[0015] In a possible implementation, when the engine system has a plurality of exhaust manifolds, the shutoff valve is located on the exhaust manifold corresponding to the most cylinders.

[0016] In a possible implementation manner, an air pressure sensor is further provided between the exhaust manifold and the shut-off valve, and an exhaust temperature sensor is provided between the aftertreatment system and the turbocharger;

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

[0018] In a possible implementation manner, a front intercooler temperature sensor and a rear intercooler temperature sensor are respectively provided before and after the intake intercooler on the turbocharger passage, an intake air temperature sensor is provided on a common passage before the turbine circulation loop and the EGR circulation loop, and an EGR temperature sensor is further provided after the EGR bypass valve of the EGR passage;

[0019] The intercooler front temperature sensor, the intercooler rear temperature sensor, the intake air temperature sensor, and the EGR temperature sensor are all communicatively connected to the ECU.

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

[0021] Acquiring engine status information, wherein the engine status information includes at least one of the following information: rotation speed and / or torque;

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

[0023] When the working state is a low-load state and a low-speed state, the shut-off valve and the EGR bypass valve are subjected to a first opening control, wherein the first opening control includes: reducing the opening of the shut-off valve to increase the gas pressure of the EGR passage, and reducing the opening of the EGR bypass valve to perform a first adjustment on the gas ratio of the EGR cooler and the EGR bypass pipe, wherein the first adjustment includes: reducing the gas passing through the EGR cooler and increasing the gas in the EGR bypass pipe;

[0024] When the working state is a high load state and / or a high speed state, a second opening control is performed on the shut-off valve and the EGR bypass valve, and the second opening control includes: increasing the opening of the shut-off valve to reduce the gas pressure in the EGR passage, and increasing the opening of the EGR bypass valve to perform a second adjustment on the gas ratio of the EGR cooler and the EGR bypass pipe, and the second adjustment includes: increasing the gas passing through the EGR cooler and reducing the gas in the EGR bypass pipe.

[0025] In a possible implementation manner, the engine water temperature is obtained; if the water temperature is lower than a preset water temperature threshold, the cut-off valve and the EGR bypass valve are controlled to a first opening degree;

[0026] If the water temperature is higher than a preset water temperature threshold, the engine status information is obtained.

[0027] In a possible implementation manner, an air pressure sensor is further provided between the exhaust manifold and the shut-off valve for detecting the input air pressure of the EGR passage, and reducing the opening of the shut-off valve includes:

[0028] When the input gas pressure is less than or equal to a preset gas pressure threshold, controlling the opening of the shut-off valve to decrease to a first opening, wherein the preset gas pressure threshold is a minimum gas pressure required to drive the gas in the EGR passage;

[0029] The step of increasing the opening of the stop valve comprises:

[0030] When the input air pressure is greater than a preset air pressure threshold, the opening of the stop valve is controlled to increase to a second opening, and the first opening is smaller than the second opening.

[0031] In a possible implementation manner, controlling the opening of the stop valve to decrease to a first opening includes:

[0032] Determining a first adjustment range of the stop valve according to a pressure difference between the preset pressure threshold and the input pressure;

[0033] According to the first adjustment range of the stop valve, controlling the opening of the stop valve to decrease to the first opening;

[0034] The step of controlling the opening of the stop valve to increase to a second opening comprises:

[0035] determining a second adjustment range of the stop valve according to a pressure difference between the input air pressure and the preset air pressure threshold;

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

[0037] In a possible implementation manner, an exhaust temperature sensor is provided between the aftertreatment system and the turbocharger for detecting the exhaust temperature output by the turbocharger, and the reducing the opening of the EGR bypass valve includes:

[0038] Acquiring the exhaust temperature output by the turbocharger;

[0039] If the exhaust gas temperature output by the turbocharger is less than or equal to the operating temperature of the post-treatment system, controlling the EGR bypass valve to decrease to a third opening degree;

[0040] The increasing the opening of the EGR bypass valve includes:

[0041] If the exhaust gas temperature output by the turbocharger is greater than the operating temperature of the post-treatment system, the EGR bypass valve is controlled to increase to a fourth opening degree, and the third opening degree is smaller than the fourth opening degree.

[0042] In a possible implementation manner, controlling the EGR bypass valve to decrease to a third opening degree includes:

[0043] determining a first adjustment amplitude of the EGR bypass valve according to a first temperature difference between an operating temperature of the aftertreatment system and the exhaust temperature;

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

[0045] The controlling the EGR bypass valve to increase to a fourth opening degree includes:

[0046] determining a second adjustment amplitude of the EGR bypass valve according to a second temperature difference between the exhaust temperature and the operating temperature of the post-treatment system;

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

[0048] In a third aspect, an embodiment of the present application provides an ECU to implement a control method of an EGR system of an engine as described above.

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

[0050] The engine EGR system, control method and vehicle provided in the embodiments of the present application, based on the acquired engine working state, control the opening of the set stop valve 3, EGR bypass pipe 7 and EGR bypass valve 8, so that when the vehicle is in a low-speed and low-load working condition, the gas exhausted by the engine 1 passes through the exhaust manifold 2, and under the action of the low-opening stop valve 3 and EGR bypass valve 8, the air pressure in the EGR passage and the EGR bypass pipe 7 is increased, thereby forcing the gas to flow to the intake end of the engine 1, thereby avoiding the defects of the existing scheme that the gas in the pipeline cannot circulate to the intake end of the engine 1 through the air pressure difference under low-speed and low-load conditions, and the after-treatment system fails to reach the working temperature, thereby improving the working effect of the vehicle's exhaust gas circulation and after-treatment system. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0052] Figure 1 Schematic diagram of the existing EGR system provided for this application;

[0053] Figure 2 A schematic diagram of the EGR system structure of the engine provided in this application;

[0054] Figure 3 The control method flow diagram of the EGR system of the engine provided in this application is as follows: Figure 1 ;

[0055] Figure 4 The control method flow diagram of the EGR system of the engine provided in this application is as follows: Figure 2 ;

[0056] Figure 5 The operation logic diagram provided for this application;

[0057] Figure 6 The control method flow diagram of the EGR system of the engine provided in this application is as follows: Figure 3 ;

[0058] Figure 7 A schematic diagram of the structure of the electronic device provided in this application.

[0059] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0060] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0061] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in one or more embodiments of this specification are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards, and corresponding operation entrances shall be provided for users to choose to authorize or refuse.

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

[0063] The existing exhaust gas treatment solutions for fuel vehicles include SCR (Selective Catalyst Reduction) system and EGR (exhaust gas recirculation) system. The SCR system uses the catalyst in the post-treatment system to react nitrogen oxides in the exhaust gas with the reducing agent to generate harmless nitrogen and water vapor, thereby achieving the purpose of reducing nitrogen oxide emissions in the exhaust gas. However, with the continuous improvement of environmental protection and emission regulations, the post-treatment system alone can no longer meet the ever-increasing requirements. Therefore, the EGR system is required to treat the exhaust gas of fuel vehicles. Compared with the SCR system, the EGR system has a simpler post-treatment system, but the combustion conditions are relatively balanced.

[0064] Figure 1 It is a schematic diagram of the existing EGR system. Figure 1As shown, the EGR system reduces the combustion temperature by returning part of the engine exhaust gas to the intake system, thereby reducing the generation of nitrogen oxides in the exhaust gas. The existing EGR system generally drives the gas through the difference between the pre-turbocharger pressure and the post-intercooler pressure. However, under low-speed and low-load conditions, due to turbocharging, the air pressure in the pipeline where the turbocharger is located is greater than the air pressure in the pipeline where the EGR cooler is located. Therefore, the gas in the pipeline where the EGR cooler is located can rarely flow back to the engine. As a result, when the vehicle is in a low-speed and low-load condition, the EGR system is insufficient for gas driving due to the small difference between the pre-turbocharger pressure and the post-intercooler pressure. It is impossible to effectively realize the forced drive of the gas in the pipeline. That is, it is difficult to introduce gas in the existing EGR system, resulting in poor exhaust gas circulation effect.

[0065] At the same time, in the existing EGR system, since the after-treatment system needs to start working when the gas temperature reaches a preset working temperature such as above 180 degrees, the high temperature of the exhaust gas needs to be maintained to reduce the emission of nitrogen oxides. However, in the existing EGR system, the EGR cooler cools the exhaust gas, so that the cooled exhaust gas flows back to the intake system, lowering the combustion temperature, so that the temperature of the gas exhausted by the engine cannot reach the working temperature of the after-treatment system, thereby reducing the amount of nitrogen oxides treated by the after-treatment system, that is, the working effect of the after-treatment system in the existing EGR system is poor.

[0066] An analysis of the working process of the above-mentioned existing EGR system shows that the EGR system cannot effectively realize the forced driving of the gas in the pipeline when the vehicle is in a low-speed and low-load condition; at the same time, due to the cooling of the exhaust gas by the cooler in the pipeline, the engine discharges the exhaust gas with a low temperature, which cannot meet the requirement of the post-treatment system to achieve normal operation based on high temperature. Therefore, in the existing EGR system, since it is impossible to effectively realize the driving of the gas in the pipeline and avoid the low exhaust gas temperature, when the vehicle is in a low-speed and low-load condition, the exhaust gas circulation effect and the working effect of the post-treatment system are poor, which in turn makes the combustion of the engine poor and cannot reduce the emission of nitrogen oxides in the exhaust gas.

[0067] In view of this, Figure 2 The schematic diagram of the EGR system structure of the engine provided in this application is as follows: Figure 2 As shown, the present application provides an EGR system of an engine, comprising: an engine system, an EGR passage, a turbocharger passage, and a post-treatment system. The engine system, the turbocharger passage, and the engine system are sequentially connected through pipelines to form a turbine circulation loop; the engine system, the EGR passage, and the engine system are sequentially connected through pipelines to form an EGR circulation loop.

[0068] Among them, the engine system includes an engine 1 and an exhaust manifold 2 connected by a pipeline, and 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 in parallel, 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 provided with: a turbocharger, an intake intercooler 9 in sequence, the turbocharger comprises a turbocharger turbine 4 and a turbocharger compressor 5, and a shut-off valve 3 is provided between the engine 1 and the turbocharger on the turbo circulation loop.

[0070] Furthermore, the shut-off valve 3 is located on the exhaust manifold 2, or on a pipe between the exhaust manifold 2 and a turbocharger. When the engine system has a plurality of exhaust manifolds 2, the shut-off 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, and is used for after-treating the exhaust gas of the turbocharger and then discharging it into the air.

[0072] Furthermore, an air pressure sensor 14 is provided between the exhaust manifold 2 and the stop valve 3, and an exhaust temperature sensor 15 is provided between the after-treatment system and the turbocharger. Both the air pressure sensor 14 and the exhaust temperature sensor 15 are communicatively connected to the ECU (Electronic Control Unit). When the air pressure obtained by the air pressure sensor 14 is less than a preset air pressure threshold, and the exhaust temperature obtained by the exhaust temperature sensor 15 is less than or equal to the operating temperature of the after-treatment system, it is confirmed that the operating state of the engine 1 is a low-load state and a low-speed state.

[0073] An intercooler front temperature sensor 10 and an intercooler rear temperature sensor 11 are respectively provided before and after the intake intercooler 9 on the turbocharger passage, an intake air temperature sensor 12 is provided on the common passage of the turbine circulation loop and the EGR circulation loop before the engine 1, and an EGR temperature sensor 13 is also provided after the EGR bypass valve 8 of the EGR passage.

[0074] Among them, the intercooler front temperature sensor 10, the intercooler rear temperature sensor 11, the intake air 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. The ECU controls the opening of the shut-off valve 3 and the EGR bypass valve 8 based on the recorded temperature data information.

[0075] Furthermore, the EGR temperature sensor 13 can obtain the gas temperature of the EGR cooler 6 and the EGR bypass pipe 7 after being adjusted 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 intercooler 9; the intake temperature sensor 12 can detect and obtain the gas temperature before entering the intake end of the engine 1.

[0076] The present application provides an EGR system for an engine. By providing a stop valve 3, an EGR bypass pipe 7 and an EGR bypass valve 8, when the vehicle is in a low-speed and low-load operating condition, the gas exhausted by the engine 1 passes through the exhaust manifold 2. Under the action of the stop valve 3 with a low opening, a small amount of gas enters the pipeline where the turbocharger is located, and a large amount of gas enters the pipeline where the EGR cooler 6 and the EGR bypass pipe 7 are located, thereby forcing the gas to flow to the intake end of the engine 1, thereby avoiding the defect of the existing solution that the gas in the pipeline cannot circulate to the intake end of the engine 1 through the air pressure difference under low-speed and low-load operating conditions, thereby improving the exhaust gas circulation working effect when the vehicle is in a low-speed and low-load operating condition.

[0077] The present application provides an engine EGR system, under the action of the stop valve 3, when the gas enters the pipeline where the EGR cooler 6 and the EGR bypass pipe 7 are located, the opening of the EGR bypass valve 8 is controlled to control the amount of gas entering the EGR cooler 6 and the EGR bypass pipe 7. When the EGR bypass valve 8 is opened at a low degree, the amount of gas in the EGR bypass pipe 7 is more, and when the EGR bypass valve 8 is opened at a high degree, the amount of gas in the EGR cooler 6 is more. By controlling the amount of gas passing through the EGR cooler 6, the temperature of the gas flowing to the intake end of the engine 1 is controlled. For example, at low speed and low load, the EGR bypass valve 8 is controlled to have a low opening, so that more gas passes through the EGR bypass pipe 7 to avoid the EGR cooler 6 from cooling the gas. Based on the uncooled gas passing through the EGR bypass pipe 7, the exhaust temperature after the engine is cold started is increased, so that the after-treatment system reaches the operating temperature as soon as possible, and the emission of nitrogen oxides meets the limit value, so that when the vehicle is in a low speed and low load condition, the working effect of the after-treatment system can still be guaranteed.

[0078] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are 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 may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0079] Based on the EGR system structure of the above engine, Figure 3 The control method flow diagram of the EGR system of the engine provided in this application is as follows: Figure 1 , combined with Figure 2 and Figure 3 As shown, the method includes:

[0080] S101. Acquire engine status information, where the engine status information includes at least one of the following information: rotation speed and / or torque.

[0081] Specifically, the current vehicle status is detected, and whether the vehicle is started normally is indicated by the current vehicle status. When the vehicle is started normally, the engine water temperature rises, so the engine water temperature is obtained through the ECU, and whether the vehicle is cold started is confirmed based on the engine water temperature.

[0082] Furthermore, when the vehicle is cold-started, the shut-off valve 3 and the EGR bypass valve 8 are controlled to respective preset openings by the ECU. When the vehicle is not cold-started, the current engine speed and torque are continuously collected by the ECU as engine status information.

[0083] S102: Determine the working state of the engine according to the engine state information.

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

[0085] S103. When the working state is a low-load state and a low-speed state, the shut-off valve and the EGR bypass valve are subjected to a first opening control, wherein the first opening control includes: reducing the opening of the shut-off valve to increase the gas pressure in the EGR passage, and reducing the opening of the EGR bypass valve to perform a first adjustment on the gas ratio of the EGR cooler and the EGR bypass pipe, wherein the first adjustment includes: reducing the gas passing through the EGR cooler and increasing the gas in the EGR bypass pipe.

[0086] Specifically, after determining the working state of the engine according to the engine state information, when the working state of the engine 1 is a low-load state and a low-speed state, after the gas exhausted by the engine 1 passes through the exhaust manifold 2, the opening of the shut-off valve 3 is reduced, that is, under the action of the shut-off valve 3 with a low opening, most of the gas passing through the exhaust manifold 2 enters the EGR passage, that is, the gas pressure in the EGR passage is increased, thereby avoiding the inability of the gas to circulate in the pipeline to the intake end of the engine 1 due to insufficient pressure between the engine 1 and the exhaust manifold 2 under low-speed and low-load conditions.

[0087] Furthermore, for the gas entering the EGR passage, in the EGR passage, by controlling the opening of the EGR bypass valve, under the action of the EGR bypass valve 8 with a low opening, most of the gas in the EGR passage passes through the EGR bypass pipe 7, and a small part passes through the EGR cooler 6, that is, the first adjustment of the gas ratio between the EGR cooler 6 and the EGR bypass pipe 7 is achieved, thereby avoiding the low temperature of the gas discharged from the engine 1 under low speed and low load conditions due to the cooling of the gas by the EGR cooler 6, so that the after-treatment system fails to reach the operating temperature and the after-treatment system cannot work normally.

[0088] S104. When the working state is a high load state and / or a high speed state, a second opening control is performed on the shut-off valve and the EGR bypass valve. The second opening control includes: increasing the opening of the shut-off valve to reduce the gas pressure in the EGR passage, and increasing the opening 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 includes: 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, when the working state of the engine 1 is a high-load state and / or a high-speed state, after the gas exhausted by the engine 1 passes through the exhaust manifold 2, due to the increase in the opening of the shut-off valve 3, that is, under the action of the high-opening shut-off valve 3, the gas passing through the exhaust manifold 2 enters the EGR passage and the turbocharger passage. At this time, under the high-load state and / or high-speed state, due to the pressure between the engine 1 and the exhaust manifold 2, the gas can circulate in the pipeline to the intake end of the engine 1.

[0090] Furthermore, for the gas entering the EGR passage, in the EGR passage, by controlling the opening of the EGR bypass valve, under the action of the EGR bypass valve with a high opening, most of the gas in the EGR passage passes through the EGR cooler, and a small part passes through the EGR bypass pipe 7, because the temperature of the gas exhausted by the engine 1 under high load and / or high speed conditions meets the operating temperature of the after-treatment system.

[0091] The control method of the EGR system of the engine provided in the embodiment of the present application is based on the working state of the engine. By controlling the opening of the set stop valve 3, EGR bypass pipe 7 and EGR bypass valve 8, when the vehicle is in a low-speed and low-load working condition, the gas exhausted by the engine 1 passes through the exhaust manifold 2, and under the action of the low-opening stop valve 3 and EGR bypass valve 8, the air pressure in the EGR passage and the EGR bypass pipe 7 is increased, thereby forcing the gas to flow to the intake end of the engine 1, thereby avoiding the defects of the existing scheme that the gas in the pipeline cannot circulate to the intake end of the engine 1 through the air pressure difference under low-speed and low-load working conditions, and the after-treatment system fails to reach the working temperature, thereby improving the working effect of the exhaust gas circulation and after-treatment system of the vehicle.

[0092] Figure 4 The control method flow diagram of the EGR system of the engine provided in this application is as follows: Figure 2 , Figure 5 The operation logic diagram provided for this application is combined with Figure 4 and Figure 5 As shown, in this embodiment Figure 2 Based on the embodiment, a control method of the EGR system of the engine is described in detail, and the method includes:

[0093] S201, obtaining engine water temperature.

[0094] Specifically, the engine water temperature is collected by the ECU, and it is detected whether the engine water temperature is lower than the preset water temperature threshold, the test result is obtained, and it is confirmed whether the vehicle is cold started based on the test result.

[0095] S202: If the water temperature is lower than a preset water temperature threshold, performing a first opening control on the shut-off valve and the EGR bypass valve.

[0096] Among them, if the detection result indicates that the water temperature is lower than the preset water temperature threshold, it is confirmed that the vehicle is cold started, and 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 pressure, and the opening of the EGR bypass valve 8 is reduced to the preset cold start bypass opening, so that the air pressure passing through the EGR cooler 6 reaches the preset cooling target pressure, and the air pressure in the EGR bypass pipe 7 reaches the preset bypass target pressure, wherein the preset bypass target pressure is greater than the preset cooling target pressure.

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

[0098] Specifically, if the detection result indicates that the water temperature is higher than the preset water temperature threshold and it is confirmed that the vehicle is not cold started, the corresponding working state is determined according to the speed and torque in the engine status information, so that the ECU can determine the corresponding working state according to the engine status information and control the opening of the shut-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 step S102, and will not be repeated here.

[0101] S205. When the operating state is a low-load state and a low-speed state, detect 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 and detected by an air pressure sensor arranged between the exhaust manifold 2 and the shut-off valve 3, and the opening of the shut-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, control the opening of the shut-off valve to decrease to a first opening, and the preset air pressure threshold is a minimum air pressure required to drive the gas in the EGR passage.

[0104] Specifically, after the input air pressure is obtained 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 since the engine is in a low-load state and a low-speed state, the gas exhausted by the engine 1 passes through the exhaust manifold 2, and the air pressure difference between the exhaust manifold 2 and the shut-off valve 3 is small, and the gas in the pipeline cannot circulate to the intake end of the engine 1, so the opening of the shut-off valve 3 is controlled to be reduced to the first opening.

[0105] Furthermore, when the opening of the stop valve 3 is controlled to be reduced to a first opening, the first adjustment range of the stop valve is determined in the air pressure opening adjustment correspondence table according to the pressure difference between the preset air pressure threshold and the input air pressure, and the opening of the stop valve is controlled to be reduced to the first opening according to the first adjustment range of the stop valve, wherein the opening adjustment correspondence table pre-stores a corresponding relationship between the air pressure difference and the adjustment range, and the air pressure difference and the adjustment range are positively correlated.

[0106] Furthermore, of course, the gas flow rate entering the EGR passage and the turbocharger passage can be controlled by controlling the opening of the shut-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 operating temperature of the post-treatment system, controlling the EGR bypass valve to decrease to a third opening degree.

[0108] Specifically, the exhaust temperature output by the turbocharger is obtained by setting an exhaust temperature sensor between the after-treatment system and the turbocharger. If the exhaust temperature output by the turbocharger is less than or equal to the operating temperature of the after-treatment system, such as one hundred and eighty degrees, and when the operating state of the engine 1 is a low-load state and a low-speed state, it is determined that the temperature of the gas exhausted by the engine 1 after passing through the exhaust manifold 2 is low because the engine is in a low-load state and a low-speed state, and thus cannot meet the operating temperature of the after-treatment system.

[0109] Therefore, it is necessary to determine the first adjustment range of the EGR bypass valve in the temperature opening adjustment correspondence table according to the first temperature difference between the operating temperature of the after-treatment system and the exhaust temperature, and control the EGR bypass valve to be reduced to a third opening according to the first adjustment range of the EGR bypass valve.

[0110] The temperature opening adjustment correspondence table pre-stores the correspondence between the temperature difference and the adjustment range. The temperature difference and the adjustment range are positively correlated. The operating temperature of the after-treatment system is lower than the exhaust temperature, that is, the operating temperature of the after-treatment system is lower than the gas temperature output by the turbocharger.

[0111] Furthermore, of course, the gas flow rate output from the EGR cooler 6 and the EGR bypass pipe 7 can be controlled by controlling the opening of the EGR bypass valve 8, thereby controlling the different temperatures of the gas flowing into the intake end of the engine 1.

[0112] The control method of the EGR system of the engine provided in the embodiment of the present application is based on the working state of the engine. By controlling the opening of the set stop valve 3, EGR bypass pipe 7 and EGR bypass valve 8, when the vehicle is in a low-speed and low-load working condition, the gas exhausted by the engine 1 passes through the exhaust manifold 2, and under the action of the low-opening stop valve 3 and EGR bypass valve 8, the air pressure in the EGR passage and the EGR bypass pipe 7 is increased, thereby forcing the gas to flow to the intake end of the engine 1, thereby avoiding the defects of the existing scheme that the gas in the pipeline cannot circulate to the intake end of the engine 1 through the air pressure difference under low-speed and low-load working conditions, and the after-treatment system fails to reach the working temperature, thereby improving the working effect of the exhaust gas circulation and after-treatment system of the vehicle.

[0113] Figure 6 The control method flow diagram of the EGR system of the engine provided in this application is as follows: Figure 3 ,like Figure 6 As shown, in this embodiment Figure 3Based on the embodiment, when the working state of the engine is a high load state and / or a high speed state, a control method of the EGR system of the engine is described in detail, and the method includes:

[0114] S301. When the working state is a high-load state and / or a high-speed state, detect the input gas pressure of the EGR passage.

[0115] Specifically, the air pressure sensor disposed between the exhaust manifold 2 and the shutoff valve 3, and the exhaust temperature sensor disposed between the post-treatment system and the turbocharger are used to collect and detect the input air pressure of the EGR passage and the exhaust temperature output by the turbocharger. The opening of the shutoff valve 3 is controlled according to the input air pressure and the working state, and the opening 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 a preset air pressure threshold, control the opening of the stop valve to increase to a second opening, and the first opening is smaller than the second opening.

[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 a high load state and / or a high speed state, it is determined that the situation in which the gas cannot circulate to the intake end of the engine 1 due to the working state of the engine 1 being a low load state and a low speed state has not occurred, and therefore the opening of the shut-off valve 3 is controlled to be reduced to a second opening, so that the gas exhausted from the engine 1 can pass through the EGR passage and the turbocharger passage in a balanced manner through the exhaust manifold 2.

[0118] Furthermore, for controlling the opening of the stop valve 3 to be reduced to a second opening, according to the pressure difference between the input air pressure and the preset air pressure threshold, the second adjustment amplitude of the stop valve 3 is determined in the air pressure opening adjustment correspondence table, and according to the second adjustment amplitude of the stop valve 3, the opening of the stop valve 3 is controlled to increase to the second opening, wherein the opening adjustment correspondence table pre-stores the correspondence between the pressure difference and the adjustment amplitude.

[0119] Furthermore, of course, the gas flow rate entering the EGR passage and the turbocharger passage can be controlled by controlling the opening of the shut-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 operating temperature of the post-treatment system, controlling the EGR bypass valve to increase to a fourth opening, and the third opening is smaller than the fourth opening.

[0121] Specifically, when it is detected that the exhaust temperature output by the turbocharger is greater than the operating temperature of the after-treatment system, and when the operating state of the engine 1 is a high-load state and / or a high-speed state, it is determined that the EGR cooler 6 does not cool the gas due to the operating state of the engine 1 being a low-load state and a low-speed state, so that the after-treatment system cannot meet the operating temperature. Therefore, the EGR bypass valve 8 is controlled to increase to the fourth opening so that the gas can pass through the EGR cooler 6 and the EGR bypass pipe 7.

[0122] Furthermore, for controlling the EGR bypass valve 8 to increase to a fourth opening degree, according to a second temperature difference between the exhaust temperature and the operating temperature of the after-treatment system, a second adjustment range of the EGR bypass valve 8 is determined in the temperature opening adjustment correspondence table, and according to the second adjustment range of the EGR bypass valve, the EGR bypass valve 8 is controlled to increase to a fourth opening degree.

[0123] Furthermore, of course, the gas flow rate output from the EGR cooler 6 and the EGR bypass pipe 7 can be controlled by controlling the opening of the EGR bypass valve 8, thereby controlling the different temperatures of the gas flowing into the intake end of the engine 1.

[0124] The control method of the EGR system of the engine provided in the embodiment of the present application is based on the working state of the engine. By controlling the opening of the set stop valve 3, EGR bypass pipe 7 and EGR bypass valve 8, when the vehicle is in a low-speed and low-load working condition, the gas exhausted by the engine 1 passes through the exhaust manifold 2, and under the action of the low-opening stop valve 3 and EGR bypass valve 8, the air pressure in the EGR passage and the EGR bypass pipe 7 is increased, thereby forcing the gas to flow to the intake end of the engine 1, thereby avoiding the defects of the existing scheme that the gas in the pipeline cannot circulate to the intake end of the engine 1 through the air pressure difference under low-speed and low-load working conditions, and the after-treatment system fails to reach the working temperature, thereby improving the working effect of the exhaust gas circulation and after-treatment system of the vehicle.

[0125] The present application also provides an ECU for implementing the control method of the EGR system of the above-mentioned engine.

[0126] The present application also provides a vehicle, comprising the above-mentioned ECU and EGR system.

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

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

[0129] The specific implementation process of the processor 701 can be found in the above method embodiment, and its implementation principle and technical effect are similar, so this embodiment will not be repeated here.

[0130] In the above embodiments, it should be understood that the processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the invention can be directly implemented as a hardware processor, or can be implemented by a combination of hardware and software modules in the processor.

[0131] The memory may include a high-speed memory (Random Access Memory, RAM), and may also include a non-volatile memory (NVM), such as at least one disk storage.

[0132] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (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 ease of representation, the bus in the drawings of this application is not limited to only one bus or one type of bus.

[0133] The present application also provides a computer program product, including a computer program, which implements the above method when executed by a processor.

[0134] The present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the above method is implemented.

[0135] The above-mentioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, 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 memory, 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 a 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 a component of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (Application Specific Integrated Circuits, referred to as: ASIC). Of course, the processor and the readable storage medium can also exist in the device as discrete components.

[0137] The division of units is only a logical function division, and there may be other divisions in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

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

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

[0140] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0141] Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to program instructions. 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, disk or optical disk and other media that can store program codes.

[0142] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary technical means in the art not disclosed by the present invention, are not limited to the precise structure described above and shown in the drawings, and may be modified and changed in various ways without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. An EGR system of an engine, characterized in that: The EGR system includes: an engine system, an EGR passage, a turbocharger passage and a post-treatment system; Wherein, the engine system, the turbocharging passage, and the engine system are sequentially connected through pipelines to form a turbine circulation loop; The engine system, the EGR passage, and the engine system are sequentially connected through pipelines to form an EGR circulation loop; The engine system includes 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 in parallel, and the outlet of the EGR cooler and the outlet of the EGR bypass pipe are both connected to the EGR bypass valve; The turbocharger passage is provided with: a turbocharger and an air intake intercooler in sequence; A shutoff valve is provided between the engine and the turbocharger on the turbine circulation loop; The aftertreatment system is connected to the turbocharger through a pipeline, and is used for after-treating the gas exhausted by the turbocharger and then discharging it into the air.

2. The EGR system according to claim 1, characterized in that: The shut-off valve is located on the exhaust manifold, or on a pipeline between the exhaust manifold and the turbocharger.

3. The EGR system according to claim 2, characterized in that: When the engine system has a plurality of exhaust manifolds, the shutoff valve is located on the exhaust manifold corresponding to the most cylinders.

4. The EGR system according to any one of claims 1 to 3, characterized in that: An air pressure sensor is also provided between the exhaust manifold and the shut-off valve, and an exhaust temperature sensor is provided between the post-treatment system and the turbocharger; The air pressure sensor and the exhaust temperature sensor are both communicatively connected to the ECU.

5. The EGR system according to claim 4, characterized in that: The intake intercooler on the turbocharger passage is provided with a front intercooler temperature sensor and a rear intercooler temperature sensor respectively before and after the intake intercooler, the turbine circulation loop and the EGR circulation loop are provided with an intake air temperature sensor on a common passage before the engine, and an EGR temperature sensor is further provided after the EGR bypass valve of the EGR passage; The intercooler front temperature sensor, the intercooler rear temperature sensor, the intake air temperature sensor, and the EGR temperature sensor are all communicatively connected to the ECU.

6. A method for controlling an EGR system of an engine, characterized in that: Applied to the EGR system according to any one of claims 1 to 5, the method comprising: Acquiring engine status information, wherein the engine status information includes at least one of the following information: rotation speed and / or torque; determining the working state of the engine 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 subjected to a first opening control, wherein the first opening control includes: reducing the opening of the shut-off valve to increase the gas pressure of the EGR passage, and reducing the opening of the EGR bypass valve to perform a first adjustment on the gas ratio of the EGR cooler and the EGR bypass pipe, wherein the first adjustment includes: 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, a second opening control is performed on the shut-off valve and the EGR bypass valve, and the second opening control includes: increasing the opening of the shut-off valve to reduce the gas pressure in the EGR passage, and increasing the opening of the EGR bypass valve to perform a second adjustment on the gas ratio of the EGR cooler and the EGR bypass pipe, and the second adjustment includes: increasing the gas passing through the EGR cooler and reducing the gas in the EGR bypass pipe.

7. The method according to claim 6, characterized in that The obtaining of engine status information comprises: Get engine water temperature; If the water temperature is lower than a preset water temperature threshold, performing a first opening control on the shut-off valve and the EGR bypass valve; If the water temperature is higher than a preset water temperature threshold, the engine status information is obtained.

8. The method according to claim 6 or 7, characterized in that: An air pressure sensor is further provided between the exhaust manifold and the stop valve for detecting the input air pressure of the EGR passage. The reducing the opening of the stop valve comprises: When the input gas pressure is less than or equal to a preset gas pressure threshold, controlling the opening of the shut-off valve to decrease to a first opening, wherein the preset gas pressure threshold is a minimum gas pressure required to drive the gas in the EGR passage; The step of increasing the opening of the stop valve comprises: When the input air pressure is greater than a preset air pressure threshold, the opening of the stop valve is controlled to increase to a second opening, and the first opening is smaller than the second opening.

9. The method according to claim 8, characterized in that The step of controlling the opening of the stop valve to decrease to a first opening comprises: Determining a first adjustment range of the stop valve according to a pressure difference between the preset pressure threshold and the input pressure; According to the first adjustment range of the stop valve, controlling the opening of the stop valve to decrease to the first opening; The step of controlling the opening of the stop valve to increase to a second opening comprises: determining a second adjustment range of the stop valve according to a pressure difference between the input air pressure and the preset air pressure threshold; According to the second adjustment range of the stop valve, the opening of the stop valve is controlled to increase to a second opening.

10. The method according to claim 6 or 7, characterized in that: An exhaust temperature sensor is provided between the post-processing system and the turbocharger for detecting the exhaust temperature output by the turbocharger. The reducing the opening of the EGR bypass valve comprises: Acquiring the exhaust temperature output by the turbocharger; If the exhaust gas temperature output by the turbocharger is less than or equal to the operating temperature of the post-treatment system, controlling the EGR bypass valve to decrease to a third opening degree; The increasing the opening of the EGR bypass valve includes: If the exhaust gas temperature output by the turbocharger is greater than the operating temperature of the post-treatment system, the EGR bypass valve is controlled to increase to a fourth opening degree, and the third opening degree is smaller than the fourth opening degree.

11. The method according to claim 10, characterized in that The controlling the EGR bypass valve to decrease to a third opening degree includes: determining a first adjustment amplitude of the EGR bypass valve according to a first temperature difference between an operating temperature of the aftertreatment system and the exhaust temperature; According to the first adjustment range of the EGR bypass valve, controlling the EGR bypass valve to decrease to the third opening degree; The controlling the EGR bypass valve to increase to a fourth opening degree includes: determining a second adjustment amplitude of the EGR bypass valve according to a second temperature difference between the exhaust temperature and the operating temperature of the post-treatment system; The EGR bypass valve is controlled to increase to the fourth opening degree according to the second adjustment range of the EGR bypass valve.

12. An ECU, characterized in that: Used to perform the method according to any one of claims 6 to 11.

13. A vehicle, characterized in that: The invention comprises the EGR system according to any one of claims 1 to 5 and the ECU according to claim 12.

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