WO2023273567A1

WO2023273567A1 - Engine exhaust gas recirculation system and control method

Info

Publication number: WO2023273567A1
Application number: PCT/CN2022/089177
Authority: WO
Inventors: 韩令海; 张宇璠; 王占峰; 李春雨; 马赫阳; 黄平慧; 李华; 宫艳峰
Original assignee: 中国第一汽车股份有限公司
Priority date: 2021-06-30
Filing date: 2022-04-26
Publication date: 2023-01-05
Also published as: CN113279883B; CN113279883A

Abstract

Provided are an engine exhaust gas recirculation system and a control method. The circulation system comprises a discharge device (1), an engine oil heating device (2) and a recirculation device (3). The discharge device (1) comprises a plurality of cylinders (11). The engine oil heating device (2) comprises an engine oil heat exchanger (21) that is in communication with the discharge assembly (12) and heats engine oil with exhaust gas. The recirculation device (3) comprises a circulation assembly (31) and a power storage assembly (32), wherein the circulation assembly (31) comprises an EGR storage tank (311) and a plurality of intake pipelines (312); and the power storage assembly (32) comprises a power generation mechanism (321), a storage battery (322) and an EGR pump (323), the power generation mechanism (321) charging the storage battery (322) with exhaust gas energy, and the storage battery (322) and the power generation mechanism (321) being electrically connected to the EGR pump (323) to pressurize the exhaust gas in the EGR storage tank (311).

Description

Engine exhaust gas recirculation system and control method

This application claims the priority of the Chinese patent application with application number 202110738960.8 submitted to the China Patent Office on June 30, 2021, the entire content of which is incorporated by reference in this application.

technical field

The present application relates to the technical field of energy saving and emission reduction of automobile engines, for example, to an engine exhaust gas recirculation system and a control method.

Background technique

With the increasingly stringent emission regulations and fuel consumption regulations, the primary goal of automobile development is to save energy and reduce emissions. Exhaust Gas Recirculation (EGR) technology can reduce knocking tendency and exhaust gas loss, improve fuel economy, and is an important development direction of automobile fuel-saving technology. In the cold start stage of the car, since the engine water temperature is much lower than the normal running temperature (90°C), the fuel consumption and emission of the engine will deteriorate during the slow heating process. Therefore, shortening the engine warm-up time and realizing rapid warm-up can obviously Reduces engine fuel consumption and improves emissions of harmful pollutants. In addition, during the normal operation stage of the engine, the exhaust gas temperature is too high to limit the EGR rate of the exhaust gas recirculation system, usually the maximum EGR rate is not more than 25%, the energy of the exhaust gas cannot be fully utilized, and the fuel saving potential needs to be further improved.

Contents of the invention

The present application provides an engine exhaust gas recirculation system and a control method, which can shorten the engine cold start warm-up time, improve the fuel economy of the vehicle, achieve a greater EGR rate, and fully tap the fuel-saving potential.

An engine exhaust gas recirculation system is provided, comprising: an exhaust device comprising a plurality of cylinders and an exhaust assembly communicating with exhaust ports of the plurality of cylinders, the exhaust assembly configured to exhaust the Exhaust gas generated by the plurality of cylinders; an oil heating device, the oil heating device includes an oil heat exchanger, the oil heat exchanger communicates with the exhaust assembly, and the oil heat exchanger is configured to use the exhaust gas to heat the oil and a recirculation device, the recirculation device includes: a circulation assembly, the circulation assembly includes an EGR storage tank and a plurality of intake pipelines, the air inlet of the EGR storage tank communicates with the exhaust assembly, and the EGR storage tank The gas outlet of the tank is respectively connected to the first ends of the plurality of air intake pipelines, and the second ends of the plurality of air intake pipelines are respectively connected to the air inlets of the plurality of cylinders; the power storage component, the power storage component It includes a power generation mechanism, a storage battery and an EGR pump, the power generation mechanism communicates with the exhaust assembly, the power generation mechanism is configured to use the energy of the exhaust gas to charge the storage battery, the storage battery and the power generation mechanism are electrically connected to the An EGR pump in communication with the EGR storage tank, the EGR pump configured to pressurize the exhaust gas within the EGR storage tank.

As an optional structure of the present application, the power generation mechanism includes: an EGR heat exchanger, the EGR heat exchanger communicates with the exhaust assembly; a thermoelectric generator, the thermoelectric generator communicates with the EGR heat exchanger, And electrically connected to the storage battery, the thermoelectric generator is configured to convert the energy of the exhaust gas into electrical energy.

As an optional structure of the present application, the power storage assembly further includes a parallel switch and a series switch, the two ends of the parallel switch are respectively electrically connected to the battery and the EGR pump, and the two ends of the series switch are respectively The thermoelectric generator and the EGR pump are electrically connected.

As an optional structure of the present application, the oil heating device further includes an oil heating exhaust pipeline valve, and the two ends of the oil heating exhaust pipeline valve are respectively connected to the discharge assembly and the oil heat exchanger .

As an optional structure of the present application, the recirculation device further includes an energy conversion tank, the first end of the energy conversion tank is connected to the discharge assembly, and the second end of the energy conversion tank is connected to the circulation assembly in parallel and the power storage component.

As an optional structure of the present application, the recirculation device further includes an EGR exhaust pipeline valve, and both ends of the EGR exhaust pipeline valve communicate with the discharge assembly and the energy conversion tank respectively.

As an optional structure of the present application, the recirculation device further includes an EGR valve, and two ends of the EGR valve communicate with the energy conversion tank and the EGR storage tank respectively.

As an optional structure of the present application, the circulation assembly further includes a plurality of cylinder intake pipe valves, the first ends of the plurality of cylinder intake pipe valves are all connected to the EGR storage tank, and the plurality of cylinder intake pipe valves are connected to the EGR storage tank. The second end of the valve communicates with the plurality of cylinders respectively.

A control method is provided, which is applied to control the above engine exhaust gas recirculation system, including: the car starts cold start, the engine works, the oil heating exhaust pipeline valve is opened, the EGR exhaust pipeline valve is closed, the engine oil heat exchanger works, The exhaust gas discharged from the exhaust assembly is all used to heat the engine oil; the oil temperature of the engine oil is detected, and when the actual oil temperature of the engine oil is higher than the lower limit of the engine oil temperature, the EGR exhaust pipeline valve is opened, and the engine oil heats up. The exchanger continues to work; when the actual oil temperature of the engine oil is higher than the upper limit of the oil temperature, the oil heating exhaust pipeline valve is closed, and the oil heat exchanger stops working; the EGR heat exchanger is working, and the EGR valve is closed , the thermoelectric generator uses the energy of all the exhaust gas to charge the battery; when the power of the battery is greater than or equal to the battery charging lower limit, the EGR heat exchanger continues to work, the thermoelectric generator continues to charge the battery, and the The EGR valve, part of the exhaust gas enters the EGR storage tank, and is used to circulate into multiple cylinders; when the battery power is greater than or equal to the charging limit of the battery, the EGR heat exchanger stops working, and all the exhaust gas enters the EGR storage tank , used to cycle into the plurality of cylinders; in the case that the battery charge drops to the lower limit of the battery charge, repeat the above. Continue to work, the thermoelectric generator continues to charge the battery, open the EGR valve, part of the exhaust gas enters the EGR storage tank, and is used to circulate into multiple cylinders; when the battery power is greater than or equal to the upper limit of battery charging, The EGR heat exchanger stops working, and all exhaust gas enters the EGR storage tank for circulation into the plurality of cylinders.

As an optional technical solution of the present application, the EGR heat exchanger continues to work and the thermoelectric generator continues to charge the battery when the battery power is greater than or equal to the battery charging lower limit, Open the EGR valve, part of the exhaust gas enters the EGR storage tank for circulation into multiple cylinders and the EGR heat exchanger stops working when the battery power is greater than or equal to the upper limit of battery charging, and all the exhaust gas enters the storage tank The EGR storage tank, which is used to circulate into the plurality of cylinders, also includes: the EGR pump works to pressurize the exhaust gas in the EGR storage tank, according to the target EGR rate of each cylinder in the plurality of cylinders, through A plurality of cylinder intake pipe valves adjust the flow of exhaust gas entering the plurality of cylinders; when the required power of the EGR pump is greater than the power of the thermoelectric generator, the parallel switch and the series switch are connected, and the battery and the The thermoelectric generators jointly drive the EGR pump; when the required power of the EGR pump is less than or equal to the power of the thermoelectric generator, the parallel switch is turned off, and the thermoelectric generator drives the EGR pump.

Description of drawings

Fig. 1 is a schematic structural diagram of an engine exhaust gas recirculation system provided in Embodiment 1 of the present application;

FIG. 2 is a flow chart of the control method provided in Embodiment 2 of the present application.

In the picture:

1, discharge device; 11, cylinder; 111, cylinder one; 1111, exhaust sensor one; 112, cylinder two; 1121, exhaust sensor two; 113, cylinder three; 1131, exhaust sensor three; 114, cylinder four; 1141. Exhaust sensor four; 12. Emission assembly; 13. Exhaust main pipe; 14. Emission sensor;

2. Oil heating device; 21. Oil heat exchanger; 22. Oil heating exhaust pipeline valve; 23. Oil heating exhaust pipeline; 24. Temperature sensor;

3. Recirculation device; 31. Circulation component; 311. EGR storage tank; 312. Intake pipeline; 3121. Intake pipeline one; 3122. Intake pipeline two; 3123. Intake pipeline three; 3124. Intake pipeline four ; 313, cylinder intake pipe valve; 3131, intake pipe valve one; 3132, intake pipe valve two; 3133, intake pipe valve three; 3134, intake pipe valve four; 314, EGR sensor one; 315, EGR sensor two; 316, EGR sensor three; 317, EGR sensor four; 32, power storage components; 321, power generation mechanism; 3211, EGR heat exchanger; 3212, thermoelectric generator; 322, battery; 323, EGR pump; 324, parallel switch; 325, Series switch; 33, energy conversion tank; 34, EGR exhaust pipeline valve; 35, EGR valve; 36, EGR exhaust pipeline; 37, EGR outlet pipeline;

4. Air filter;

5. Air intake device; 51. Intake manifold one; 52. Intake manifold two; 53. Intake manifold three; 54. Intake manifold four;

6. Exhaust tailpipe device.

detailed description

The application will be described below in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments described here are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, the drawings only show structures of relevant parts of the present application.

In the description of this application, unless otherwise clearly specified and limited, the terms "connected", "connected" and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrated ; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those of ordinary skill in the art can understand the meanings of the above terms in this application according to the situation.

In this application, unless otherwise expressly specified and limited, a first feature being "on" or "under" a second feature may include direct contact between the first and second features, and may also include the first and second features Not in direct contact but through another characteristic contact between them. Moreover, "above", "above" and "above" the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. "Below", "beneath" and "under" the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

In the description of this embodiment, the terms "up", "down", "left", "right" and other orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operations. It is not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed, or operate in a particular orientation, and thus should not be construed as limiting the application. In addition, the terms "first" and "second" are only used to distinguish in description, and have no special meaning.

Embodiment one

As shown in FIG. 1 , an embodiment of the present application provides an engine exhaust gas recirculation system, including an exhaust device 1 , an oil heating device 2 and a recirculation device 3 . The discharge device 1 includes a plurality of cylinders 11 and a discharge assembly 12 , the discharge assembly 12 communicates with the exhaust port of each cylinder 11 , and the discharge assembly 12 is configured to discharge exhaust gas generated by the plurality of cylinders 11 . In the embodiment of the present application, the plurality of cylinders 11 are cylinder one 111 , cylinder two 112 , cylinder three 113 and cylinder four 114 . Cylinder one 111, cylinder two 112, cylinder three 113 and cylinder four 114 are provided with exhaust sensor one 1111, exhaust sensor two 1121, exhaust sensor three 1131 and exhaust sensor four 1141 respectively on the air outlet pipelines of cylinder one 111, cylinder two 112, cylinder three 113 and cylinder four 114. Each exhaust gas sensor is configured to monitor the exhaust gas displacement of its corresponding cylinder. In other embodiments, other numbers of cylinders and exhaust sensors may also be provided according to the requirements of the vehicle system, which is not limited to this embodiment. The exhaust assembly 12 also includes an exhaust manifold 13 and an emission sensor 14. The two ends of the exhaust manifold 13 are respectively connected to a plurality of cylinders 11 and the exhaust assembly 12, and the exhaust gas entering the exhaust assembly 12 from the exhaust manifold 13 is monitored in real time by the emission sensor 14. flow.

The oil heating device 2 includes an oil heat exchanger 21 communicating with the discharge assembly 12 and configured to heat the oil using exhaust gas. When the car is cold started, since the engine water temperature is much lower than the temperature (90°C) during normal operation, the fuel consumption and emission of the engine will deteriorate during the slow heating process. Realize rapid warm-up, reduce fuel consumption and emissions. Optionally, the oil heating device 2 also includes an oil heating exhaust pipeline 23, an oil pan, and a temperature sensor 24; The exhaust pipeline 23 is set to convey the exhaust gas discharged from the exhaust assembly 12; the oil heat exchanger 21 uses the energy of the exhaust gas to heat the oil in the oil pan, and measures the real-time temperature of the oil through the temperature sensor 24, which is convenient for monitoring.

The recycling device 3 includes a circulation component 31 and an electrical storage component 32 . The circulation assembly 31 includes an EGR storage tank 311 and a plurality of intake pipelines 312, the intake port of the EGR storage tank 311 communicates with the exhaust assembly 12, and the multiple gas outlets of the EGR storage tank 311 respectively communicate with the first ends of the plurality of intake pipelines 312 , the second ends of the plurality of intake pipelines 312 communicate with the intake ports of the plurality of cylinders 11 respectively. The power storage assembly 32 includes a power generation mechanism 321, a battery 322 and an EGR pump 323. The power generation mechanism 321 is connected to the exhaust assembly 12. The power generation mechanism 321 is configured to use exhaust gas to charge the battery 322. The battery 322 and the power generation mechanism 321 are both electrically connected to the EGR pump 323. An EGR pump 323 communicates with the EGR storage tank 311 , and the EGR pump 323 is configured to pressurize exhaust gas within the EGR storage tank 311 . In the embodiment of the present application, the recirculation device 3 further includes an EGR exhaust pipeline 36 and an EGR outlet pipeline 37, one end of the EGR exhaust pipeline 36 communicates with the exhaust assembly 12, and the EGR exhaust pipeline 36 is configured as a circulation assembly 31 and the power storage assembly 32 transport the exhaust gas discharged from the exhaust assembly 12; the two ends of the EGR outlet pipeline 37 are respectively connected to the EGR storage tank 311 and the EGR exhaust pipeline 36, and the EGR outlet pipeline 37 is set to deliver exhaust gas to the EGR storage tank 311 .

In the embodiment of the present application, the engine exhaust gas recirculation system further includes an air filter 4 , an intake device 5 and an exhaust tailpipe device 6 . The air filter 4 communicates with the intake device 5 to filter the gas that is about to enter a plurality of cylinders; wherein the intake device 5 includes an intake manifold one 51, an intake manifold two 52, an intake manifold three 53 and an intake manifold 53. Air manifold four 54, four intake manifolds communicate with cylinder one 111, cylinder two 112, cylinder three 113 and cylinder four 114 respectively. The exhaust tailpipe device 6 is connected to the oil heat exchanger 21 and is arranged to discharge excess exhaust gas to the outside of the system.

In the engine exhaust gas recirculation system of the embodiment of the present application, the pipeline connected to the exhaust device 1 is divided into two, so that the exhaust assembly 12 is connected in parallel with the oil heating device 2 and the recirculation device 3, so as to make full use of the exhaust gas energy and shorten the engine cold start time. Warm-up time, to achieve rapid warm-up, can significantly reduce the fuel consumption rate of the engine and improve the emission of harmful pollutants, improve the actual fuel economy of the vehicle; the pipeline of the recirculation device 3 is also divided into two, through the power generation mechanism 321 Part of the exhaust gas is energy recovered, and the energy is converted into electric energy to charge the battery 322. On the one hand, the temperature of the EGR exhaust gas is reduced after energy recovery, and a large EGR rate can be achieved, which can reach 50%. On the other hand, the charged battery 322 can drive the EGR pump 323 to pressurize the exhaust gas in the EGR storage tank 311, more fully utilize the energy of the exhaust gas, and form a controllable circulation of the energy of the exhaust gas.

The power generating mechanism 321 includes an EGR heat exchanger 3211 and a thermoelectric generator 3212 . The EGR heat exchanger 3211 communicates with the exhaust assembly 12; the thermoelectric generator 3212 communicates with the EGR heat exchanger 3211 and is electrically connected to the battery 322. The thermoelectric generator 3212 is configured to convert the energy of exhaust gas into electrical energy. Through the EGR heat exchanger 3211 and the thermoelectric generator 3212, the energy of the exhaust gas is converted, and the thermal energy is converted into electric energy, and the storage battery 322 is charged.

The power storage assembly 32 also includes a parallel switch 324 and a series switch 325 , the two ends of the parallel switch 324 are electrically connected to the battery 322 and the EGR pump 323 respectively, and the two ends of the series switch 325 are electrically connected to the thermoelectric generator 3212 and the EGR pump 323 respectively. When the required power of the EGR pump 323 was greater than the power of the thermoelectric generator 3212, the parallel switch 324 and the series switch 325 were connected, and the storage battery 322 and the thermoelectric generator 3212 jointly drove the EGR pump 323; when the required power of the EGR pump 323 was less than or equal to the thermoelectric generator When the power of 3212 is turned off, the parallel switch 324 is turned off, and the thermoelectric generator 3212 drives the EGR pump 323 . By connecting the parallel switch 324 and the series switch 325, the mode of driving the EGR pump 323 by the battery 322 and the thermoelectric generator 3212 can be selected according to the exhaust gas pressure requirement in the system, so as to utilize the energy of the exhaust gas more efficiently.

The engine oil heating device 2 also includes an engine oil heating exhaust pipeline valve 22 , the two ends of the engine oil heating exhaust pipeline valve 22 communicate with the discharge assembly 12 and the engine oil heat exchanger 21 respectively. The engine oil heating exhaust pipeline valve 22 is configured to control whether the engine oil heating exhaust pipeline 23 is connected or not. After the temperature of the heated oil reaches the upper limit of the oil temperature, close the oil heating exhaust pipeline valve 22, and no longer use the exhaust gas to heat the oil, so as to avoid the excessive temperature of the oil of the engine.

The recirculation device 3 also includes an energy conversion tank 33 , the first end of the energy conversion tank 33 is connected to the discharge assembly 12 , and the second end of the energy conversion tank 33 is connected to the circulation assembly 31 and the power storage assembly 32 in parallel. The energy conversion tank 33 is configured to receive exhaust gas discharged from the exhaust assembly 12 , and optionally, the EGR heat exchanger 3211 is disposed in the energy conversion tank 33 .

The recirculation device 3 also includes an EGR exhaust pipeline valve 34 , the two ends of the EGR exhaust pipeline valve 34 communicate with the discharge assembly 12 and the energy conversion tank 33 respectively. Optionally, the EGR exhaust pipeline valve 34 is arranged on the EGR exhaust pipeline 36 , and is configured to control whether the EGR exhaust pipeline 36 is connected or not. In the cold start stage of the engine, when the actual temperature of the engine oil does not reach the lower limit of the oil temperature, it is necessary to close the EGR exhaust pipeline valve 34, and use all the exhaust gas to heat the engine oil through the oil heat exchanger 21, so as to achieve the purpose of fast warm-up. When the actual temperature of the engine oil reaches the lower limit of the engine oil temperature, the EGR exhaust pipeline valve 34 is opened.

The recirculation device 3 further includes an EGR valve 35 , and the two ends of the EGR valve 35 communicate with the energy conversion tank 33 and the EGR storage tank 311 respectively. Optionally, the EGR valve 35 is arranged on the EGR outlet pipeline 37 to control whether the EGR outlet pipeline 37 is connected or not. During the normal operation of the engine, when the battery 322 is less than the battery 322 charging lower limit, the EGR valve 35 needs to be closed, and the thermoelectric generator 3212 uses the energy of all exhaust gas to charge the battery 322 .

The circulation assembly 31 also includes a plurality of cylinder intake pipe valves 313 , the first ends of the plurality of cylinder intake pipe valves 313 are connected to the EGR storage tank 311 , and the second ends of the plurality of cylinder intake pipe valves 313 are respectively connected to the plurality of cylinders 11 . In the embodiment of the present application, the circulation assembly 31 also includes an intake pipeline 1 3121 , an intake pipeline 2 3122 , an intake pipeline 3 3123 and an intake pipeline 4 3124 ; the four intake pipelines are respectively provided with an EGR sensor 1 314 and an EGR sensor Two 315, EGR sensor three 316 and EGR sensor four 317. Cylinder intake pipe valve 313 comprises intake pipe valve one 3131, intake pipe valve two 3132, intake pipe valve three 3133 and intake pipe valve four 3134, these four closing valves respectively control intake pipe one 3121, intake pipe two 3122, intake pipe Whether the gas pipeline three 3123 and the intake pipeline four 3124 are respectively connected to cylinder one 111, cylinder two 112, cylinder three 113 and cylinder four 114, EGR sensor one 314, EGR sensor two 315, EGR sensor three 316 and EGR sensor four 317 are monitored respectively Flow and pressure of exhaust gas entering cylinder one 111 , cylinder two 112 , cylinder three 113 and cylinder four 114 . According to the engine running conditions during the actual driving of the vehicle, the cylinder intake pipe valve 313 can intelligently adjust the ratio of exhaust gas and air entering multiple cylinders 11, reduce the unevenness of exhaust gas from multiple cylinders, achieve optimal economic matching, and fully tap the savings of the system. Oil potential, breaking the limit of the maximum EGR rate of the conventional exhaust gas recirculation system.

The engine exhaust gas recirculation system of the embodiment of the present application breaks the limitation of the maximum EGR rate of the conventional exhaust gas recirculation system, can realize a larger EGR rate, and fully tap the fuel-saving potential of the exhaust gas recirculation system; The warm-up time of cold start improves the actual fuel economy of the vehicle.

Embodiment two

As shown in FIG. 2 , this embodiment of the present application provides a control method, which is applied to the engine exhaust gas recirculation system in Embodiment 1, and includes the following steps.

Step S1, the car starts cold start, the engine works, the engine oil heating exhaust pipeline valve 22 is opened, the EGR exhaust pipeline valve 34 is closed, the engine oil heat exchanger 21 works, and the exhaust gas discharged from the exhaust assembly 12 is used to heat the engine oil.

When the car is cold started, since the engine water temperature is much lower than the temperature during normal operation, by closing the EGR exhaust pipeline valve 34, all the exhaust gas discharged from the exhaust assembly 12 can be heated by the oil heating exhaust pipeline 23 to heat the engine oil to achieve rapid The purpose of warming up is to reduce fuel consumption and emissions. Optionally, before this step S1, it is necessary to determine whether the engine is working, and only when the engine is working normally, step S1 is started.

Step S2: Detect the oil temperature of the engine oil. When the real-time oil temperature of the engine oil is higher than the lower limit of the engine oil temperature, the EGR exhaust pipeline valve 34 is opened, and the engine oil heat exchanger 21 continues to work.

According to the temperature sensor 24 to monitor the temperature in real time, after the oil temperature rises to the lower limit T _WL of the oil temperature, the EGR exhaust pipeline valve 34 is opened to reduce the exhaust gas entering the oil heating exhaust pipeline 23 . As shown in Figure 2, T _W represents the real-time temperature of the oil, T _WL represents the lower limit of the oil temperature, and T _WH represents the upper limit of the oil temperature.

Step S3, when the real-time oil temperature of the engine oil is higher than the upper limit of the engine oil temperature, close the oil heating exhaust pipeline valve 22, the engine oil heat exchanger 21 stops working; the EGR heat exchanger 3211 works, close the EGR valve 35, and the thermoelectric generator 3212 The battery 322 is charged with the energy of all the exhaust gas.

According to the real-time monitoring temperature of the temperature sensor 24, after the engine oil temperature rises to the upper limit T _WH of the engine oil temperature, the cold start phase ends and the engine enters the normal operation phase. At this time, the exhaust gas is no longer needed for engine oil heating. At this time, the engine oil heating is turned off. The exhaust pipeline valve 22 and the engine oil heat exchanger 21 stop working. All the exhaust gas discharged from the exhaust assembly 12 enters the recirculation device 3 through the EGR exhaust pipeline 36, the EGR valve 35 is closed, the EGR heat exchanger 3211 works, and the thermoelectric generator 3212 uses the energy of all the exhaust gas to charge the battery 322, so as to achieve as fast as possible The target power level for charging the battery 322 is reached.

Step S4, when the power of the battery 322 is greater than or equal to the battery charging lower limit, the thermoelectric generator 3212 continues to work to charge the battery 322, and the EGR valve 35 is opened, and part of the exhaust gas enters the EGR storage tank 311 for circulation into multiple cylinders 11.

When the electric energy in the battery 322 reaches the battery charging lower limit SOC _L , the energy of all the exhaust gas is no longer needed. At this time, the EGR valve 35 is opened to allow part of the exhaust gas to enter the EGR storage tank 311 for circulation into multiple cylinders 11 . As shown in FIG. 2 , the actual state of charge percentage of the battery 322 is SOC, the battery charge lower limit _SOCL , and the battery charge upper limit _SOCH .

Step S5 , when the power of the battery 322 is greater than or equal to the charging limit of the battery, the EGR heat exchanger 3211 stops working, and all exhaust gas enters the EGR storage tank 311 for circulation into multiple cylinders 11 .

In the process of continuously charging the battery 322, when the actual power SOC of the battery 322 reaches the battery charging upper limit SOC _H , it is no longer necessary to continue charging the battery 322 to avoid damage to the battery 322 and energy waste caused by overcharging. The EGR heat exchanger 3211 stops working, and all the exhaust gas enters the EGR storage tank 311 for circulation into multiple cylinders 11 .

Step S6, when the power of the storage battery 322 drops to the lower limit of battery charging, repeat steps S4 to S5. Through the real-time monitoring of the electric quantity of the storage battery 322, intelligent management of exhaust gas energy can be realized.

Simultaneously with the above step S4 and step S5, the method further includes the following steps.

SS1, the EGR pump 323 works, pressurizes the exhaust gas in the EGR storage tank 311, and adjusts the exhaust gas entering the multiple cylinders 11 through the intake pipe valve 313 of the multiple cylinders according to the target EGR rate of each cylinder 11 in the multiple cylinders 11 flow; when the required power of the EGR pump 323 was greater than the power of the thermoelectric generator 3212, the parallel switch 324 and the series switch 325 were connected, and the storage battery 322 and the thermoelectric generator 3212 jointly drove the EGR pump 323; when the required power of the EGR pump 323 was less than or equal to the temperature difference When the power of the generator 3212 is turned off, the parallel switch 324 is turned off, and the thermoelectric generator 3212 drives the EGR pump 323 .

When the battery 322 reaches the battery charge lower limit, the EGR pump 323 can start to pressurize the exhaust gas in the EGR storage tank 311 to perform exhaust gas circulation. Through the inlet pipe valve one 3131, the inlet pipe valve two 3132, the inlet pipe valve three 3133 and the inlet pipe valve four 3134 on the inlet pipeline one 3121, the inlet pipeline two 3122, the inlet pipeline three 3123 and the inlet pipeline four 3124, Intelligently and precisely adjust the flow of exhaust gas entering cylinder one 111, cylinder two 112, cylinder three 113 and cylinder four 114, EGR sensor one 314, EGR sensor two 315, EGR sensor three 316 and EGR sensor four 317 respectively monitor the flow of exhaust gas entering cylinder one 111, The exhaust gas flow and pressure of cylinder two 112, cylinder three 113 and cylinder four 114 are fed back. According to the real-time combustion stability and air-fuel ratio in the cylinder, intelligently and precisely control the ratio of exhaust gas and air of multiple cylinders to achieve the target EGR rate, which can reach a maximum of 50%, and solve the problem of uneven EGR rate of multiple cylinders. As shown in Figure 2, CY1 represents cylinder one 111, CY2 represents cylinder two 112, CY3 represents cylinder three 113, and CY4 represents cylinder four 114. The system adopts proportional integration differentiation (PID) control, which is more accurate. How to implement PID control through sensors and pipe valves is a related technology in the field, and will not be repeated in this embodiment.

According to the power required by the EGR pump 323 , the parallel switch 324 and the series switch 325 can intelligently control the manner in which the battery 322 and the thermoelectric generator 3212 drive the EGR pump 323 , so as to utilize the energy of the exhaust gas more efficiently. As shown in Figure 2, P is the required power of the EGR pump 323, and P _W is the power generated by the temperature difference; The generator 3212 jointly drives the EGR pump 323; when the required power of the EGR pump 323 is less than or equal to the power of the thermoelectric generator 3212, the parallel switch 324 is turned off, and the thermoelectric generator 3212 drives the EGR pump 323.

The control method of the embodiment of the present application controls the exhaust gas recirculation system of the engine according to the engine running conditions during the actual running of the vehicle, controls the flow direction of the exhaust gas, adjusts the flow of the exhaust gas, and realizes the intelligent and controllable circulation of the exhaust gas.

Claims

An engine exhaust gas recirculation system, comprising:

A discharge device (1), the discharge device (1) comprising a plurality of cylinders (11) and a discharge assembly (12), the discharge assembly (12) communicating with the exhaust ports of the plurality of cylinders (11), the an exhaust assembly (12) configured to exhaust exhaust gas generated by the plurality of cylinders (11);

An oil heating device (2), the oil heating device (2) includes an oil heat exchanger (21), the oil heat exchanger (21) communicates with the discharge assembly (12), and the oil heat exchanger (21 ) is configured to use said exhaust gas to heat engine oil; and

Recirculation device (3), described recirculation device (3) comprises:

Circulation assembly (31), described circulation assembly (31) comprises exhaust gas recirculation (Exhaust Gas Recirculation, EGR) storage tank (311) and a plurality of intake pipelines (312), the intake air of described EGR storage tank (311) The gas outlet of the EGR storage tank (311) is respectively connected to the first ends of the multiple intake pipelines (312), and the first ends of the multiple intake pipelines (312) The two ends are respectively connected to the intake ports of the plurality of cylinders (11);

an electric storage assembly (32), the electric storage assembly (32) includes a power generation mechanism (321), a storage battery (322) and an EGR pump (323), the power generation mechanism (321) communicates with the discharge assembly (12), the The power generating mechanism (321) is configured to use the energy of the exhaust gas to charge the battery (322), the battery (322) and the power generating mechanism (321) are electrically connected to the EGR pump (323), the An EGR pump (323) communicates with the EGR storage tank (311), the EGR pump (323) being configured to pressurize the exhaust gas within the EGR storage tank (311).
The engine exhaust gas recirculation system according to claim 1, wherein the power generating mechanism (321) comprises:

an EGR heat exchanger (3211), the EGR heat exchanger (3211) communicating with the exhaust assembly (12);

a thermoelectric generator (3212), the thermoelectric generator (3212) communicates with the EGR heat exchanger (3211), and is electrically connected to the storage battery (322), and the thermoelectric generator (3212) is configured to convert the The energy of the exhaust gas is converted into electrical energy.
The engine exhaust gas recirculation system according to claim 2, wherein the power storage assembly (32) further comprises a parallel switch (324) and a series switch (325), and the two ends of the parallel switch (324) are respectively electrically connected to The storage battery (322) and the EGR pump (323), the two ends of the series switch (325) are respectively electrically connected to the thermoelectric generator (3212) and the EGR pump (323).
The exhaust gas recirculation system of an engine according to claim 3, wherein the oil heating device (2) further comprises an oil heating exhaust pipeline valve (22), and two valves (22) of the engine oil heating exhaust pipeline valve (22) The ends communicate with the discharge assembly (12) and the oil heat exchanger (21) respectively.
The engine exhaust gas recirculation system according to claim 4, wherein the recirculation device (3) further comprises an energy conversion tank (33), and the first end of the energy conversion tank (33) communicates with the exhaust assembly ( 12), the second end of the energy conversion tank (33) is connected in parallel with the circulation component (31) and the power storage component (32).
The engine exhaust gas recirculation system according to claim 5, wherein the recirculation device (3) further comprises an EGR exhaust pipeline valve (34), and the two ends of the EGR exhaust pipeline valve (34) are respectively It communicates with the discharge assembly (12) and the energy conversion tank (33).
The engine exhaust gas recirculation system according to claim 6, wherein the recirculation device (3) further comprises an EGR valve (35), and both ends of the EGR valve (35) communicate with the energy conversion tank (33) respectively ) and the EGR storage tank (311).
The engine exhaust gas recirculation system according to claim 7, wherein the circulation assembly (31) further comprises a plurality of cylinder intake pipe valves (313), and the first ends of the plurality of cylinder intake pipe valves (313) are each It communicates with the EGR storage tank (311), and the second ends of the multiple cylinder intake pipe valves (313) communicate with the multiple cylinders (11) respectively.
A control method applied to control the exhaust gas recirculation system of an engine according to claim 1, comprising:

The car starts cold start, the engine works, the engine oil heating exhaust pipeline valve (22) is opened, the exhaust gas recirculation (Exhaust Gas Recirculation, EGR) exhaust pipeline valve (34) is closed, the engine oil heat exchanger (21) works, and the exhaust The exhaust gas discharged from the assembly (12) is all used for heating the engine oil;

Detect the oil temperature of the engine oil, and when the actual oil temperature of the engine oil is higher than the lower limit of the engine oil temperature, open the EGR exhaust pipeline valve (34), and the engine oil heat exchanger (21) continues to work;

When the actual oil temperature of the engine oil is higher than the upper limit of the engine oil temperature, close the oil heating exhaust pipeline valve (22), the engine oil heat exchanger (21) stops working; the EGR heat exchanger (3211) works , close the EGR valve (35), and the thermoelectric generator (3212) uses the energy of all the exhaust gas to charge the battery (322);

When the electric quantity of the storage battery (322) is greater than or equal to the charging lower limit of the storage battery, the EGR heat exchanger (3211) continues to work, the thermoelectric generator (3212) continues to charge the storage battery (322), and the EGR valve (35), part of the exhaust gas enters the EGR storage tank (311) for circulation into multiple cylinders (11);

When the electric quantity of the storage battery (322) is greater than or equal to the charging upper limit of the storage battery, the EGR heat exchanger (3211) stops working, and all exhaust gas enters the EGR storage tank (311) for circulation into the plurality of cylinders (11);

When the electric quantity of the storage battery (322) drops to the lower limit of charging of the battery, repeat the above-mentioned condition that the electric quantity of the storage battery (322) is greater than or equal to the lower limit of charging of the battery, and the EGR heat exchanger (3211) continues to work. , the thermoelectric generator (3212) continues to charge the battery (322), opens the EGR valve (35), and part of the exhaust gas enters the EGR storage tank (311) for circulation into multiple cylinders (11); and When the electric quantity of the storage battery (322) is greater than or equal to the charging upper limit of the storage battery, the EGR heat exchanger (3211) stops working, and all exhaust gas enters the EGR storage tank (311) for circulation into the multiple storage tanks (311). cylinders (11).
According to the control method according to claim 9, when the electric quantity of the storage battery (322) is greater than or equal to the charging lower limit of the storage battery, the EGR heat exchanger (3211) continues to work, and the thermoelectric generator (3212) continuously Charge the storage battery (322), open the EGR valve (35), and part of the exhaust gas enters the EGR storage tank (311) for circulation into a plurality of cylinders (11) and the electric quantity in the storage battery (322) is greater than When it is equal to the charging upper limit of the battery, the EGR heat exchanger (3211) stops working, and all exhaust gas enters the EGR storage tank (311) for circulation into the multiple cylinders (11), and also includes:

SS1, the EGR pump (323) works, pressurizes the exhaust gas in the EGR storage tank (311), and passes through the intake pipes of multiple cylinders (11) according to the target EGR rate of each cylinder (11) in the multiple cylinders (11) The valve (313) adjusts the flow of exhaust gas entering the plurality of cylinders (11); when the required power of the EGR pump (323) is greater than the power of the thermoelectric generator (3212), the parallel switch (324 ) and a series switch (325), the storage battery (322) and the thermoelectric generator (3212) jointly drive the EGR pump (323); when the required power of the EGR pump (323) is less than or equal to the thermoelectric generator In the case of the power of the electrical appliance (3212), the parallel switch (324) is turned off, and the thermoelectric generator (3212) drives the EGR pump (323).