阅读说明：本技术 一种车用发动机有机朗肯循环余热回收装置及其控制方法 (Organic Rankine cycle waste heat recovery device for vehicle engine and control method of organic Rankine cycle waste heat recovery device ) 是由 孙爱洲 王鹏 李子非 李丽 卜兆国 徐秀华 王晓勇 于 2020-07-17 设计创作，主要内容包括：本发明涉及发动机技术领域,具体公开了一种车用发动机有机朗肯循环余热回收装置及其控制方法,该车用发动机有机朗肯循环余热回收装置包括发动机子系统、有机朗肯循环子系统和动力传动子系统,有机朗肯循环子系统包括依次连接的膨胀机、冷凝器、储液罐、工质泵、换热器和第二三通阀,工质在换热器中与发动机子系统的排放管路换热,第二三通阀能够将换热器选择性连通膨胀机和冷凝器,工质侧从废气侧吸收的热量不大于当前环境温度下冷凝器能够散发的最大热量,当膨胀机出现故障时,工质由换热器全部直接流至冷凝器,冷凝器也能够将工质吸收的发动机排气热量完全散失到环境中去,保证余热回收装置的安全可靠。(The invention relates to the technical field of engines, in particular to an organic Rankine cycle waste heat recovery device of an engine for a vehicle and a control method thereof, the organic Rankine cycle waste heat recovery device of the engine for the vehicle comprises an engine subsystem, an organic Rankine cycle subsystem and a power transmission subsystem, the organic Rankine cycle subsystem comprises an expander, a condenser, a liquid storage tank, a working medium pump, a heat exchanger and a second three-way valve which are sequentially connected, a working medium exchanges heat with a discharge pipeline of the engine subsystem in the heat exchanger, the second three-way valve can selectively communicate the heat exchanger with the expander and the condenser, the heat absorbed by the working medium from the waste gas side is not more than the maximum heat which can be dissipated by the condenser at the current ambient temperature, when the expander breaks down, the working medium directly flows to the condenser from the heat exchanger, and the condenser can also completely dissipate the, the safety and the reliability of the waste heat recovery device are ensured.)

1. The utility model provides an organic rankine cycle waste heat recovery device of automobile-used engine which characterized in that includes:

an engine subsystem comprising an exhaust gas aftertreatment device (11), a first three-way valve (12) connected to the exhaust gas aftertreatment device (11), and an exhaust line (13) connected to the first three-way valve (12), the exhaust line (13) being in communication with the atmosphere, the first three-way valve (12) being capable of selectively communicating the exhaust gas aftertreatment device (11) with the atmosphere and the exhaust line (13);

an organic Rankine cycle subsystem, which comprises an expander (21), a condenser (22) connected with the output end of the expander (21), a variable frequency fan (23) opposite to the condenser (22), a liquid storage tank (24) connected with the condenser (22), a working medium pump (25) connected with the liquid storage tank (24), and a heat exchanger (26) and a second three-way valve (27), wherein the second three-way valve (27) comprises an input end (271), a first output end (272) and a second output end (273), the heat exchanger (26) comprises a working medium side and a waste gas side, the two ends of the working medium side are respectively connected with the working medium pump (25) and the input end (271), the two ends of the waste gas side are connected in series with the discharge pipeline (13), the first output end (272) is connected with the expander (21), and the second output end (273) is connected with the condenser (22), the input end (271) is selectively communicated with the first output end (272) and the second output end (273), and the heat absorbed by the working medium side from the waste gas side is equal to the maximum heat capable of being emitted by the condenser (22) at the current ambient temperature;

And the power transmission subsystem comprises a power output device main shaft (31) connected with an engine (14), an expander main shaft (32) connected with the expander (21), and an electric control speed change clutch device (33) connected with the power output device main shaft (31) and the expander main shaft (32).

2. The vehicle engine organic Rankine cycle waste heat recovery device according to claim 1, wherein the engine subsystem further comprises:

an engine (14) including an exhaust manifold (141) and an intake manifold (142);

a turbocharger (15) comprising a turbine (151) and a compressor (152) connected to the turbine (151), the turbine (151) connecting the atmosphere to the intake manifold (142), the compressor (152) connecting the exhaust manifold (141) to the exhaust gas aftertreatment device (11).

3. The method for controlling the organic Rankine cycle waste heat recovery device for the vehicle engine according to claim 1 or 2, characterized by comprising:

s1: obtaining the temperature T of the exhaust gas output by the exhaust gas aftertreatment device (11)_{exh_1}；

S2: comparison T_{exh_1}And the opening temperature T of the waste heat recovery device_startThe size of (d); if T_{exh_1}＞T_startThen execution proceeds to S3;

s3: obtaining a current ambient temperature T₀；

S4: determining the current ambient temperature T according to the map of the ambient temperature and the maximum heat dissipation capacity of the condenser (22) ₀Corresponding maximum heat removal Q of the current condenser (22)_1max；

S5: according to the formula

s6: controlling the first three-way valve (12) such that the exhaust gas flow rate of the exhaust gas discharged into the exhaust line (13) by the exhaust gas aftertreatment device (11) is equal to

4. The control method for the organic Rankine cycle waste heat recovery device for the vehicle engine according to claim 3, wherein S6 includes:

s61: obtaining the exhaust flow of the output end of the exhaust gas post-treatment device (11)If it is

s62: controlling a first three-way valve (12) to only communicate a discharge pipeline (13) and a tail gas aftertreatment device (11);

s63: controlling a first three-way valve (12) to be communicated with a discharge pipeline (13) and a tail gas post-treatment device (11) and to be communicated with the atmosphere and the tail gas post-treatment device (11), wherein the exhaust flow of the waste gas between the discharge pipeline (13) and the tail gas post-treatment device (11) is equal to that of the waste gas

5. The control method for the organic Rankine cycle waste heat recovery device for the vehicle engine according to claim 3, further comprising, after S6:

S7: according to the formulaCalculating mass flow of working medium

s8: starting the working medium pump (25) and adjusting the rotating speed of the working medium pump (25) to a target rotating speed N_pump，Where ρ is_{in_pump}Is the designed density value, V, of the working medium at the inlet of the working medium pump (25)_{disp_pump}Is the displacement of the working medium pump (25) (. eta.)_{V_pump}The volumetric efficiency of the working medium pump (25).

6. The control method for the organic Rankine cycle waste heat recovery device for the vehicle engine according to claim 5, further comprising, after S8:

s9: according to the formulaCalculating a model rotational speed N of the expander (21)_modelWherein eta_{V_exp}Is the volumetric efficiency, V, of the expander (21)_{disp_exp}Is the displacement of the expander (21) < rho >_{in_exp}The density of the working medium at the inlet of the expansion machine (21);

s10: according to formula N_act＝τ·N_engineCalculating the actual speed N of the expander (21)_actWherein tau is the gear transmission ratio of the electric control speed change clutch device (33);

s11: comparison of N_modelAnd N_actThe size of (d); if N is present_model＞N_actThen execution proceeds to S12;

s12: comparison of tau_nowAnd a maximum transmission ratio tau of an electrically controlled gear change clutch (33)_maxOf size, τ_nowIs the current gear transmission ratio of the electrically controlled speed change clutch device (33);

if tau_now＜τ_maxThen execution proceeds to S13;

s13: controlling the transmission ratio of the gear at which the electrically controlled speed change clutch device (33) is currently positioned to increase by a first value, wherein N is the first value _model＝N_act。

7. The method for controlling an organic Rankine cycle waste heat recovery device for a vehicle according to claim 6, wherein in S12, τ is_now＝τ_maxThen execution proceeds to S14;

s14: controlling the opening of the second output (273) of the second three-way valve (27) to increase by a second value, where N is_model＝N_act。

8. The method for controlling an organic Rankine cycle waste heat recovery device for a vehicle according to claim 7, wherein in S11, if N is N_model≤N_actThen execution proceeds to S15;

s15: comparison of tau_nowAnd a minimum transmission ratio tau of an electrically controlled gear change clutch (33)_minThe size of (d); if tau_now＞τ_minThen execution proceeds to S16;

s16: controlling the transmission ratio of the current gear of the electrically controlled speed change clutch device (33) to be reduced by a third set value, wherein N is the same as N_model＝N_act。

9. The method for controlling an ORC waste heat recovery device for a vehicle according to claim 8, wherein τ is at S15_now＝τ_minThen execution proceeds to S17;

s17: and controlling a second output end (273) of the second three-way valve (27) to be completely opened, controlling a first output end (272) to be completely closed, controlling an electric control speed change clutch device (33) to separate an expander main shaft (32) from a power output device main shaft (31), controlling a first three-way valve (12) to only communicate the tail gas aftertreatment device (11) with the atmosphere, and closing the working medium pump (25).

10. The method for controlling an organic Rankine cycle waste heat recovery device for a vehicle according to claim 9, wherein in S2, if T is greater than T_{exh_1}≤T_startThen S17 is executed.

Technical Field

The invention relates to the technical field of engines, in particular to an organic Rankine cycle waste heat recovery device for an automotive engine and a control method of the organic Rankine cycle waste heat recovery device.

Background

The heat equivalent converted into effective work by the engine accounts for 30-45% (diesel engine) or 20-30% (gasoline engine) of the combustion heat quantity of the fuel. The energy discharged out of the vehicle in the form of waste heat accounts for 55-70% (diesel engine) or 70-80% (gasoline engine) of the total combustion energy. The energy generated by the combustion of the automobile fuel is only about one third effectively utilized, and most energy loss is realized through the heat dissipation of cooling water of the engine and the heat dissipation of high-temperature tail gas.

In contrast, in the conventional two-stage single-screw expander organic rankine cycle diesel engine exhaust waste heat utilization system disclosed in the earlier patent with the application number of CN201010579930.9, the organic rankine cycle technology is adopted to recover the exhaust waste heat energy of the engine. The basic principle is that organic working medium absorbs waste heat of an engine in an evaporator and is evaporated into gaseous working medium, the gaseous working medium enters an expander to push the expander to do work, the gaseous organic working medium at the outlet of the expander is condensed into liquid organic working medium by a condenser and then flows back to a liquid storage tank, and the liquid organic working medium in the liquid storage tank flows out to a working medium pump to be boosted and then is sent to the evaporator to absorb the waste heat of the engine again, so that Rankine cycle is completed.

However, since the layout space of the whole vehicle is limited, the space for arranging the condenser of the organic rankine cycle waste heat recovery device is limited, and the organic rankine waste heat recovery device cannot normally work due to insufficient cooling and heat dissipation capacity of the condenser under the engine working condition with large exhaust energy of the engine. Meanwhile, in the normal work of the organic Rankine cycle waste heat recovery device, the mechanical coupling control between the shaft power output of the expander and the power output device of the engine cannot be effectively controlled.

Disclosure of Invention

The invention aims to: the organic Rankine cycle waste heat recovery device for the vehicle engine and the control method thereof are provided, and the problem that the waste heat recovery device cannot work normally due to insufficient cooling and heat dissipation capacity of a condenser under the engine working condition with large exhaust energy of the engine due to the fact that the space of the condenser for arranging the organic Rankine cycle waste heat recovery device is limited in the prior art is solved.

In one aspect, the present invention provides an organic rankine cycle waste heat recovery device for a vehicle engine, including:

an engine subsystem comprising an exhaust gas aftertreatment device, a first three-way valve connected to the exhaust gas aftertreatment device, and an exhaust line connected to the first three-way valve, the exhaust line being in communication with the atmosphere, the first three-way valve enabling the exhaust gas aftertreatment device to be selectively in communication with the atmosphere and the exhaust line;

An organic Rankine cycle subsystem comprising an expander, a condenser connected to an output of the expander, a variable frequency fan opposite to the condenser, a liquid storage tank connected with the condenser, a working medium pump connected with the liquid storage tank, and a heat exchanger and a second three-way valve, the second three-way valve comprising an input and first and second outputs, the heat exchanger comprises a working medium side and a waste gas side, two ends of the working medium side are respectively connected with the working medium pump and the input end, both ends of the exhaust gas side are connected in series with the discharge pipeline, the first output end is connected with the expansion machine, the second output end is connected with the condenser, the input end is selectively communicated with the first output end and the second output end, the heat absorbed by the working medium side from the waste gas side is equal to the maximum heat capable of being emitted by the condenser at the current ambient temperature;

and the power transmission subsystem comprises a power output device main shaft connected with the engine, an expander main shaft connected with the expander, and an electric control speed change clutch device connected with the power output device main shaft and the expander main shaft.

As a preferable technical scheme of the organic Rankine cycle waste heat recovery device for the vehicle engine, the engine subsystem further comprises:

An engine including an exhaust manifold and an intake manifold;

the turbocharger comprises a turbine and a compressor connected with the turbine, the turbine is connected with the atmosphere and the intake manifold, and the compressor is connected with the exhaust manifold and the exhaust gas aftertreatment device.

In another aspect, the present invention provides a method for controlling an organic rankine cycle waste heat recovery device for a vehicle engine according to any one of the above aspects, including:

s1: temperature T of tail gas output by tail gas post-treatment device_{exh_1}；

S2: comparison T_{exh_1}And the opening temperature T of the waste heat recovery device_startThe size of (d); if T_{exh_1}＞T_startThen execution proceeds to S3;

s3: obtaining a current ambient temperature T₀；

S4: determining the current ambient temperature T according to map of the ambient temperature and the maximum heat dissipation capacity of the condenser₀Maximum heat dissipation Q of the corresponding current condenser_1max；

S5: according to the formulaCalculating the maximum exhaust gas flow permitted on the exhaust gas side of the heat exchangerWherein, c_pSpecific heat capacity of engine exhaust, T_{exh_1}Is a heat exchangerTemperature value of the inlet of the exhaust gas side, T_{exh_2}Is the design value for the temperature of the outlet on the exhaust side of the heat exchanger;

s6: controlling the first three-way valve to make the exhaust flow of the exhaust gas discharged into the discharge pipeline by the exhaust gas post-treatment device equal to

As a preferable aspect of the control method for the organic rankine cycle waste heat recovery device for the vehicle engine, S6 includes:

S61: obtaining exhaust flow of output end of tail gas post-treatment deviceIf it isThen S62 is executed; if it isThen S63 is executed;

s62: controlling the first three-way valve to only communicate the exhaust pipeline and the tail gas aftertreatment device;

s63: controlling the first three-way valve to communicate with the exhaust pipeline and the tail gas post-treatment device and communicate with the atmosphere and the tail gas post-treatment device, wherein the exhaust flow of the waste gas between the exhaust pipeline and the tail gas post-treatment device is equal to that of the waste gas

As a preferable technical scheme of the control method of the organic rankine cycle waste heat recovery device for the vehicle engine, the method further comprises the following steps after the step S6:

s7: according to the formulaCalculating mass flow of working mediumWherein h is₁And h₂Are respectively asSpecific enthalpy design values at an outlet and an inlet of a working medium side of the heat exchanger;

s8: starting the working medium pump and adjusting the rotating speed of the working medium pump to a target rotating speed N_pump，Where ρ is_{in_pump}For the design value of the density, V, of the working medium at the inlet of the working medium pump_{disp_pump}Is the discharge capacity, eta, of the working-medium pump_{V_pump}The volumetric efficiency of the working medium pump.

The preferable technical scheme of the control method of the organic Rankine cycle waste heat recovery device for the vehicle engine further comprises the following steps after S8:

s9: according to the formulaCalculating model rotation speed N of expansion machine_modelWherein eta_{V_exp}For volumetric efficiency of expanders, V_{disp_exp}Is the displacement of the expander, p _{in_exp}The density of the working medium at the inlet of the expansion machine;

s10: according to formula N_act＝τ·N_engineCalculating the actual speed N of the expander_actWherein tau is the gear transmission ratio of the electric control speed change clutch device;

s11: comparison of N_modelAnd N_actThe size of (d); if N is present_model＞N_actThen execution proceeds to S12;

s12: comparison of tau_nowAnd maximum transmission ratio tau of electrically-controlled speed-changing clutch device_maxOf size, τ_nowThe current gear transmission ratio of the electric control speed change clutch device is obtained;

if tau_now＜τ_maxThen execution proceeds to S13;

s13: controlling the gear ratio of the current gear of the electrically controlled speed change clutch to increase by a first value, wherein N is the moment_model＝N_act。

As a preferable technical scheme of the control method of the organic Rankine cycle waste heat recovery device of the vehicle engine, the method is characterized in that in S12, if tau_now＝τ_maxThen execution proceeds to S14;

s14: controlling the opening degree of the second output end of the second three-way valve to increase by a second value, wherein N is_model＝N_act。

As a preferable technical scheme of the control method of the organic Rankine cycle waste heat recovery device of the vehicle engine, in S11, if N is high_model≤N_actThen execution proceeds to S15;

s15: comparison of tau_nowAnd minimum transmission ratio tau of electrically-controlled speed-changing clutch device_minThe size of (d); if tau_now＞τ_minThen execution proceeds to S16;

s16: controlling the transmission ratio of the current gear of the electrically controlled speed change clutch to be reduced by a third set value, wherein N is the moment_model＝N_act。

As a preferable technical scheme of the control method of the organic Rankine cycle waste heat recovery device of the vehicle engine, in S15, if tau _now＝τ_minThen execution proceeds to S17;

s17: and controlling the second output end of the second three-way valve to be completely opened, the first output end to be completely closed, controlling the electric control speed change clutch device to separate the main shaft of the expander from the main shaft of the power output device, controlling the first three-way valve to be communicated with the tail gas aftertreatment device and the atmosphere, and closing the working medium pump.

As a preferable technical scheme of the control method of the organic Rankine cycle waste heat recovery device of the vehicle engine, in S2, if T is T_{exh_1}≤T_startThen S17 is executed.

The invention has the beneficial effects that:

the invention provides an organic Rankine cycle waste heat recovery device of an engine for a vehicle and a control method thereof, and the organic Rankine cycle waste heat recovery device of the engine for the vehicle comprises: the system comprises an engine subsystem, an organic Rankine cycle subsystem and a power transmission subsystem. The engine subsystem includes tail gas aftertreatment device, the first three-way valve of being connected with tail gas aftertreatment device to and the emission pipeline of being connected with first three-way valve, the emission pipeline communicates with the atmosphere, and first three-way valve can make tail gas aftertreatment device selectivity and atmosphere and emission pipeline communicate. The organic Rankine cycle subsystem comprises an expander, a condenser connected with the output end of the expander, a variable frequency fan opposite to the condenser, a liquid storage tank connected with the condenser, a working medium pump connected with the liquid storage tank, and a heat exchanger and a second three-way valve, the second three-way valve comprises an input end, a first output end and a second output end, the heat exchanger comprises a working medium side and a waste gas side, the working medium pump and the input end are respectively connected with the two ends of the working medium side, the two ends of the waste gas side are connected in series with a discharge pipeline, the expander is connected with the first output end, the condenser is connected with the second output end, the first output end and the second output end are selectively communicated with the input end, the heat absorbed by the working medium side from the waste gas side is. The power transmission subsystem comprises a power output device main shaft connected with the engine, an expander main shaft connected with the expander, and an electric control speed change clutch device connected with the power output device main shaft and the expander main shaft. Through controlling the working medium under the current engine working condition to be equal to the maximum heat dissipation capacity of the condenser under the current environmental temperature from the heat that the waste gas side absorbs at the working medium side of the heat exchanger, so the setting, when the expander breaks down and can not normally work, the working medium can not flow into the expander again, need to close the working medium from the first output of the second three-way valve completely, the second output is opened completely, the working medium directly flows to the condenser from the bypass of the expander at this moment, the condenser also can completely scatter and disappear the working medium to the environment from the engine exhaust heat that the waste gas side of the heat exchanger absorbs, guarantee the safety and reliability of the waste heat recovery device.

Drawings

FIG. 1 is a schematic structural diagram of an organic Rankine cycle waste heat recovery device of an automotive engine in an embodiment of the invention;

FIG. 2 is a first flowchart of a control method of an organic Rankine cycle waste heat recovery device of an engine for a vehicle according to an embodiment of the invention;

fig. 3 is a second flowchart of a control method of the organic rankine cycle waste heat recovery device of the vehicle engine according to the embodiment of the invention.

In the figure:

11. an exhaust gas post-treatment device; 12. a first three-way valve; 13. a discharge line; 14. an engine; 141. an exhaust manifold; 142. an intake manifold; 15. a turbocharger; 151. a turbine; 152. a compressor;

21. an expander; 22. a condenser; 23. a variable frequency fan; 24. a liquid storage tank; 25. a working medium pump; 26. a heat exchanger; 27. a second three-way valve; 271. an input end; 272. a first output terminal; 273. a second output terminal; 28. an electrically controlled pressure relief valve;

31. a power take-off spindle; 32. a main shaft of the expander; 33. an electrically controlled speed-changing clutch device.

Detailed Description

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

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Where the terms "first position" and "second position" are two different positions, and where a first feature is "over", "above" and "on" a second feature, it is intended that the first feature is directly over and obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

As shown in fig. 1, the present embodiment provides an organic rankine cycle waste heat recovery device for an engine for a vehicle, which includes an engine subsystem, an organic rankine cycle subsystem and a power transmission subsystem.

Wherein, the engine subsystem includes exhaust aftertreatment device 11, the first three-way valve 12 of being connected with exhaust aftertreatment device 11 to and the emission pipeline 13 of being connected with first three-way valve 12, and emission pipeline 13 communicates with the atmosphere, and first three-way valve 12 can make exhaust aftertreatment device 11 selectivity communicate with atmosphere and emission pipeline 13. Preferably, the engine subsystem further includes an engine 14 and a turbocharger 15. The engine 14 includes an exhaust manifold 141 and an intake manifold 142; the turbocharger 15 comprises a turbine 151 and a compressor 152 connected to the turbine 151, the turbine 151 being connected to the atmosphere and to the intake manifold 142, the compressor 152 being connected to the exhaust manifold 141 and to the exhaust gas aftertreatment device 11. Of course, in other embodiments, the exhaust aftertreatment device 11 is directly coupled to the exhaust manifold 141 when the turbocharger 15 is not present in the engine assembly.

The orc subsystem includes an expander 21, a condenser 22 connected to an output of the expander 21, a variable frequency fan 23 opposite to the condenser 22, a liquid storage tank 24 connected with the condenser 22, a working medium pump 25 connected with the liquid storage tank 24, and with heat exchanger 26 and second three-way valve 27, second three-way valve 27 includes input 271 and first output 272 and second output 273, heat exchanger 26 includes working medium side and waste gas side, working medium pump 25 and input 271 are connected respectively to the both ends of working medium side, the both ends of waste gas side are established ties in discharge line 13, the input of expander 21 is connected to first output 272, the input of condenser 22 is connected to second output 273, input 271 selectivity intercommunication first output 272 and second output 273, the heat that the working medium side was absorbed from the waste gas side is not more than the maximum heat that condenser 22 can distribute under the current ambient temperature. In this embodiment, the first three-way valve 12 and the second three-way valve 27 are electrically controlled three-way valves. An electrically controlled pressure relief valve 8 is also arranged on the liquid storage tank 24.

The power transmission sub-system comprises a power take-off main shaft 31 connected with the engine 14, an expander main shaft 32 connected with the expander 21, and an electrically controlled variable speed clutch 33 connecting the power take-off main shaft 31 and the expander main shaft 32.

The organic Rankine cycle waste heat recovery device for the vehicle engine provided by the invention has the advantages that under the driving of the working medium pump 25, the working medium in the liquid storage tank 24 flows into the working medium side of the heat exchanger 26 through the working medium pump 25, the working medium absorbs the heat in the tail gas flowing through the waste gas side from the waste gas side of the heat exchanger 26 and flows through the second three-way valve 27, the second three-way valve 27 enables the input end 271 to be communicated with the first output end 272, the input end 271 is communicated with the second output end 273, at the moment, a part of the working medium flows into the condenser 22 after flowing through the expander 21, and the other part of the working medium directly flows; or the second three-way valve 27 enables the input end 271 to be communicated with the first output end 272 only, and at the moment, all the working medium flows through the expansion machine 21 and flows into the condenser 22; or the second three-way valve 27 enables the input end 271 to be communicated with the second output end 273 only, and the working medium directly flows into the condenser 22 at the moment. When the working medium flows through the expander 21, the working medium drives the expander main shaft 32 to rotate, and when the electric control speed change clutch device 33 is connected with the expander main shaft 32 and the power output device main shaft 31, the power can be output to the power output device main shaft 31. The working medium flowing into the condenser 22 radiates heat to the air under the blowing of the variable frequency fan 23, and then flows into the liquid storage tank 24.

According to the organic Rankine cycle waste heat recovery device for the vehicle engine, the heat absorbed by the working medium from the exhaust gas side at the working medium side of the heat exchanger 26 under the working condition of the current engine 14 is controlled to be equal to the maximum heat dissipation capacity of the condenser 22 under the current ambient temperature, so that the arrangement is that when the expander 21 fails and cannot work normally, the working medium cannot flow into the expander 21, the working medium needs to be completely closed from the first output end 272 of the second three-way valve 27, the second output end 273 is completely opened, the working medium directly flows into the condenser 22 from a bypass of the expander 21, the condenser 22 can also completely dissipate the exhaust heat of the engine 14 absorbed by the working medium from the exhaust gas side of the heat exchanger 26 into the environment, and the safety and the reliability of the waste heat recovery device are guaranteed.

As shown in fig. 2 and fig. 3, the present embodiment further provides a control method of the organic rankine cycle waste heat recovery device for the vehicle engine in the foregoing solution, which is implemented by an on-board controller, and specifically includes the following steps:

s1: obtaining the temperature T of the exhaust gas output by the exhaust gas aftertreatment device 11_{exh_1}。

The temperature T of the tail gas in the tail gas post-treatment device 11 can be acquired by the vehicle-mounted controller through the first temperature sensor arranged at the output end of the tail gas post-treatment device 11 _{exh_1}。

S2: comparison T_{exh_1}Starting temperature T of organic Rankine waste heat recovery device of automobile engine_startThe size of (d); if T_{exh_1}＞T_startThen S3 is executed.

The opening temperature T of the organic Rankine waste heat recovery device of the vehicle engine is preset in the vehicle-mounted controller_start。

S3: obtaining a current ambient temperature T₀。

The vehicle-mounted controller can acquire the front ambient temperature T through a second temperature sensor arranged on the vehicle body₀。

S4: determining the current ambient temperature T according to the map of the ambient temperature and the maximum heat dissipation capacity of the condenser 22₀Corresponding maximum heat dissipation of the current condenser 22Q_1max。

The vehicle-mounted controller is stored with map of the ambient temperature and the maximum heat dissipation capacity of the condenser 22 in advance, and the dependent variable in the map is the maximum heat dissipation capacity Q of the condenser 22_1maxThe independent variable is the current ambient temperature T₀Wherein the map can be obtained by a limited number of tests on a condenser wind tunnel test stand.

S5: according to the formula

Calculating the maximum exhaust flow allowed on the exhaust side of the heat exchanger 26Wherein, c_pSpecific heat capacity of exhaust gas, T, of engine 14_{exh_1}Is the temperature value, T, of the inlet of the exhaust gas side of the heat exchanger 26_{exh_2}Is a design value for the temperature of the outlet on the exhaust side of the heat exchanger 26.

In this embodiment, the design temperature T of the outlet on the exhaust side of the heat exchanger 26_{exh_2}At 150 ℃ and the specific heat capacity c of exhaust gas of the engine 14 _pIt was 1.03 kJ/kg. K.

S6: the first three-way valve 12 is controlled so that the exhaust flow rate of the exhaust gas discharged into the exhaust line 13 by the exhaust gas post-treatment device 11 becomes equal to

Optionally, S6 includes:

s61: obtaining the exhaust flow of the output end of the exhaust gas post-treatment device 11If it is

Then S62 is executed; if it isS63 is executed.

S62: the first three-way valve 12 is controlled to communicate only the exhaust line 13 and the exhaust gas aftertreatment device 11.

S63: controlling the first three-way valve 12 to communicate the exhaust line 13 with the exhaust gas post-treatment device 11 and to communicate the atmosphere with the exhaust gas post-treatment device 11, the exhaust flow of the exhaust gas between the exhaust line 13 and the exhaust gas post-treatment device 11 being equal to

Specifically, in this embodiment, the first three-way valve 12 includes an air inlet, an output port a and an output port b, wherein the air inlet is connected to the exhaust gas aftertreatment device 11, the output port a is communicated with the atmosphere, the output port b is communicated with the exhaust pipeline 13, a first flow sensor is arranged between the output port b and the exhaust pipeline 13, the first flow sensor is connected to an onboard controller, and the onboard controller can obtain the actual exhaust gas flow flowing into the exhaust pipeline 13 through the first flow sensorS63 can be realized by the following steps S631 to S633.

S631: the actual exhaust gas flow into the exhaust line 13 is detected

S632: comparing the actual exhaust gas flow

And

the size of (d); if it is

Then S633 is executed, if

The subsequent step S7 is executed;

s633: the on-vehicle controller controls the opening degree of the output port a of the first three-way valve 12 to be increased by one unit value, and S631 is repeated.

It should be noted that when the onboard controller determines

In time, the vehicle-mounted controller can be regarded as Wherein

Is a smaller value.

Through the above steps S1 to S6, it is ensured that the amount of heat absorbed by the working medium from the exhaust gas side at the working medium side of the heat exchanger 26 under the current engine 14 operating condition is equal to the maximum heat dissipation amount of the condenser 22 at the current ambient temperature. When the expander 21 fails and cannot work normally, the working medium can completely flow into the condenser 22 from the bypass of the expander 21, and the condenser 22 can also completely dissipate the exhaust heat of the engine 14 absorbed by the working medium from the exhaust side of the heat exchanger 26 to the environment, so that the safety and reliability of the waste heat recovery device are ensured.

Optionally, the control method of the organic rankine cycle waste heat recovery device for the vehicle engine further comprises S7 and S8 after S6.

S7: according to the formula

Calculating mass flow of working medium

Wherein h is₁And h₂The specific enthalpy design values at the outlet and inlet, respectively, of the working medium side of the heat exchanger 26. h is ₁And h₂The value of (c) is determined for a particular organic rankine cycle subsystem.

S8: starting working medium pump 25 and regulatingThe rotation speed of the mass pump 25 is adjusted to the target rotation speed N_pump，

Where ρ is_{in_pump}Is the designed density value, V, of the working medium at the inlet of the working medium pump 25_{disp_pump}Is the displacement, eta, of the working-medium pump 25_{V_pump}The volumetric efficiency of the working medium pump 25.

ρ_{in_pump}The value of (c) is determined for a particular organic rankine cycle subsystem. In the present embodiment, the displacement V of the working medium pump 25_{disp_pump}0.008L/r; volumetric efficiency eta of working medium pump 25_{V_pump}Is 0.6.

Optionally, the control method of the organic rankine cycle waste heat recovery device for the vehicle engine further comprises S9 to S14 after S8.

S9: according to the formula

Calculating model rotation speed N of expander 21_modelWherein eta_{V_exp}For volumetric efficiency, V, of the expander 21_{disp_exp}Is the displacement of the expander 21, p_{in_exp}Is the density of the working medium at the inlet of the expander 21.

In the present embodiment, the volumetric efficiency of the expander 21 is 0.6, and the displacement V of the expander 21_{disp_exp}0.13L/r, density rho of the working medium at the inlet of the expander 21_{in_exp}Is determined for a particular orc subsystem.

S10: according to formula N_act＝τ·N_engineCalculating the actual speed N of the expander 21_actWherein τ is the gear ratio of the electrically controlled speed change clutch device 33.

S11: comparison of N _modelAnd N_actThe size of (d); if N is present_model＞N_actThen S12 is executed.

S12: comparison of tau_nowAnd the maximum transmission ratio tau of the electrically controlled gearshift clutch 33_maxOf size, τ_nowIs the current gear ratio of the electrically controlled speed change clutch device 33;

if tau_now＜τ_maxThen S13 is executed.

S13: the gear ratio of the current gear of the electrically controlled speed change clutch device 33 is controlled to increase by a first value, N is measured at the moment_model＝N_act。

If the model speed N of the expander 21 is present under the current engine 14 operating condition_modelHigher than the actual speed N of the expander 21_actIf the gear ratio tau of the electrically controlled speed-change clutch device 33 is not used_nowLess than the maximum transmission ratio tau of the electrically-controlled change-speed clutch 33_maxIn this case, the actual operating speed N of the expander 21 can be controlled by controlling the electrically controlled speed change clutch 33_actIs raised to adjust the current gear ratio tau of the electrically controlled gearshift clutch 33_nowIs increased to increase the actual rotation speed N of the expander 21_actMake the expander 21 actually operate at the rotation speed N_actEqual to the model speed N of the expander 21_model. Specifically, N may be calculated by an on-board controller_act＝N_modelTime, τ_nowAnd increases the first value based on the gear ratio of the gear in which the electrically controlled shifting clutch device 33 is currently located to become the same value as the above-mentioned solution.

Alternatively, in S12, if τ_now＝τ_maxThen S14 is executed.

S14: the opening degree of the second output 273 of the second three-way valve 27 is controlled to be increased by a second value, N _model＝N_act。

Due to tau_now＝τ_maxThe actual rotation speed of the expander 21 can not be increased continuously by controlling the electrically controlled variable speed clutch 33, the second three-way valve 27 can be controlled to increase the opening degree of the second output end 273 of the second three-way valve 27, so that part of the working medium directly flows into the condenser 22 to reduce the flow rate of the working medium flowing into the expander 21, thereby reducing the model rotation speed N of the expander 21_modelThe model rotation speed N of the expander 21 is set_modelEqual to the actual operating speed N of the expander 21_act。

Specifically, the vehicle-mounted controller can calculate N through the formula_model＝N_actAt the corresponding first output end 272And calculates the flow rate of the working medium at the second output end 273 of the second three-way valve 27 according to the calculated flow rateAnd controls the second output 273 of the second three-way valve 27 to be opened to

The corresponding opening increases from zero to a second value.

Preferably, the first output 272 of the second three-way valve 27 is provided with a second flow sensor, the second flow sensor is connected with an on-board controller, and the on-board controller can obtain the flow of the working medium flowing to the expansion machine 21 through the second flow sensor and is connected with the above-mentioned working mediumAnd comparing to judge whether the two are the same, and if the two are the same, indicating that the control is accurate.

Alternatively, in S11, if N_model≤N_actThen S15 is executed.

S15: comparison of tau _nowAnd the minimum transmission ratio tau of the electrically controlled gearshift clutch 33_minThe size of (d); if tau_now＞τ_minThen S16 is executed.

S16: the gear ratio of the current gear of the electrically controlled speed change clutch device 33 is controlled to be reduced by a third value, and N is controlled to be reduced at the moment_model＝N_act。

If the model speed N of the expander 21 is present under the current engine 14 operating condition_modelNot higher than actual speed N of expander 21_actIf the gear ratio tau of the electrically controlled speed-change clutch device 33 is not used_nowGreater than the minimum transmission ratio tau of the electrically-controlled change-speed clutch 33_minIn this case, the actual operating speed N of the expander 21 can be controlled by controlling the electrically controlled speed change clutch 33_actDecreases and thereby adjusts the current gear ratio tau of the electrically controlled gearshift clutch 33_nowIs decreased to decrease the actual rotational speed N of the expander 21_actMake the actual rotation speed N of the expander 21_actEqual to the model speed N of the expander 21_model. Specifically, N may be calculated by an on-board controller_act＝N_modelTime, τ_nowAnd decreases the third value based on the gear ratio of the gear in which the electrically controlled shifting clutch device 33 is currently located to become the same value as the above-mentioned solution.

Alternatively, in S15, if τ_now＝τ_minThen S17 is executed.

S17: and controlling the second output end 273 of the second three-way valve 27 to be completely opened, controlling the first output end 272 to be completely closed, controlling the electrically-controlled speed-changing clutch device 33 to separate the expander main shaft 32 from the power output device main shaft 31, controlling the first three-way valve 12 to only communicate the tail gas aftertreatment device 11 with the atmosphere, and closing the working medium pump 25.

Model speed N of expander 21 at current engine 14 operating conditions_modelNot higher than actual speed N of expander 21_actIf tau is provided_now＝τ_minIt indicates that the actual rotation speed of the expander 21 cannot be reduced by controlling the electrically controlled speed change clutch device 33, and the expander 21 cannot normally output power to the outside. Therefore, the second output end 273 of the second three-way valve 27 is controlled to be fully opened, the first output end 272 is controlled to be fully closed, so that the working medium does not flow into the expander 21, meanwhile, the first three-way valve 12 is controlled to only communicate the exhaust gas aftertreatment device 11 with the atmosphere, the exhaust gas of the engine 14 does not flow into the exhaust gas side of the heat exchanger 26, the working medium pump 25 is closed, the electrically controlled variable speed clutch 33 is controlled to separate the expander main shaft 32 from the power output device main shaft 31, and the operation of the organic Rankine cycle subsystem is stopped. The organic Rankine cycle subsystem can be effectively protected.

Alternatively, in S2, if T_{exh_1}≤T_startThen S17 is executed.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.