Vehicle, hydraulic system for a vehicle's power train, and control method thereof

Abstract

Disclosed is a vehicle, a hydraulic system (100) for a power train of the vehicle, and a control method thereof. The hydraulic system (100) for the power train of the vehicle includes an oil tank (10), a main cooling oil passage (m), and a plurality of cooling branch passages, one end of the main cooling oil passage (m) is connected to the oil tank (10), a first oil pump (20) and a cooler (30) are provided in the main cooling oil passage (m), the plurality of cooling branch passages are connected to the other end of the main cooling oil passage (m), the first oil pump (20) pumps oil in the oil tank (10) to the cooling branch passages, each of the plurality of cooling branch passages is provided with a control element that is independently controlled, the control element controls opening and closing of the corresponding cooling branch passage, and the plurality of cooling branch passages cool at least one of a drive motor (50a), a generator (50d), a clutch (50b), and a transmission (50c).

Description

Technical Field

[0001] (Cross - reference to related applications) This application claims priority to Chinese Patent Application No. 202110406463.8, titled "Vehicle, Hydraulic System for Vehicle Power Train and Control Method Thereof", filed by BYD COMPANY LIMITED on April 15, 2021.

[0002] This application relates to the field of vehicles, and in particular, to vehicles, hydraulic systems for vehicle power trains, and control methods thereof.

Background Art

[0003] With the diversification of automotive energy, various components from different fields, including pinions, clutches, drive motors, generators, controllers, etc., are integrated into the power trains of hybrid vehicles. These components need to be cooled to operate at appropriate temperatures. In the prior art, the cooling oil circuits of multiple components are controlled by one oil pump, and the cooling oil circuits of each component are connected to the oil pump through throttle valves respectively. That is, the cooling and lubrication of each component are distributed according to the dimensional ratio of the throttle valves. Therefore, in the prior art, in order to meet the flow rate of the component with the highest cooling demand, the cooling supply for other components is likely to exceed the demand. As a result, some components cannot operate within the high - efficiency temperature range, and the efficiency of the power train is low.

Summary of the Invention

Problems to be Solved by the Invention

[0004] This application attempts to solve at least to some extent one of the technical problems in the related art.

[0005] For this reason, this application provides a vehicle, a hydraulic system for a vehicle power train, and a control method thereof, which can adjust the flow rate of each power terminal as required.

Means for Solving the Problems

[0006] A hydraulic system for a vehicle power train according to an embodiment of the first aspect of the present application, wherein the power train includes one or more of a drive motor, a generator, a clutch, and a transmission, the hydraulic system includes an oil tank, a main cooling oil passage, and a plurality of cooling branch passages. One end of the main cooling oil passage communicates with the oil tank, and a first oil pump and a cooler are provided. The plurality of cooling branch passages are connected to the other end of the main cooling oil passage. The first oil pump pumps the oil in the oil tank to the cooling branch passages. Control elements are provided in all of the plurality of cooling branch passages. The control elements control the opening and closing of the corresponding cooling branch passages. The plurality of cooling branch passages cool one or more of a drive motor, a generator, a clutch, and a transmission.

[0007] Thereby, each cooling branch passage and the control element form an integrated cooling valve group structure. Each solenoid valve independently opens and closes and adjusts the corresponding cooling branch passage to realize independent flow control, and can realize independent adjustment control of the cooling flow rate of each power terminal.

[0008] A vehicle according to an embodiment of the second aspect of the present application includes a hydraulic system, a controller, a power distribution module, a pressure calculation module, a terminal flow rate calculation module, and a hydraulic adjustment module. The controller receives driving demand information and road condition information. The power distribution module calculates the required rotational speed information and torque information for each power terminal of the power train based on the driving demand information and road condition information. The power terminal includes one or more of a drive motor, a generator, a clutch, and a transmission. The pressure calculation module calculates the required driving pressure based on the rotational speed information and torque information of the power distribution module. The terminal flow rate calculation module calculates the required cooling flow rate for each power terminal based on the rotational speed information, torque information of the power distribution module, and the temperature information of the oil in the main cooling oil passage. The hydraulic adjustment module calculates the rotational speed of the first oil pump, the rotational speed of the second oil pump, the opening degree of the control element, and the opening degree of the pressure control solenoid valve based on the required driving pressure and the required cooling flow rate for each power terminal.

[0009] The control method of the hydraulic system for the power train of a vehicle according to the embodiment of the third aspect of the present application is as follows: Calculating the required rotational speed information and torque information for each power terminal of the power train based on the driving demand information and road condition information, where the power terminal includes one or more of a drive motor, a generator, a clutch, and a transmission; calculating the driving pressure demand and the cooling flow rate demand for each power terminal based on the required rotational speed information and torque information for each power terminal; and calculating the rotational speed of the first oil pump, the rotational speed of the second oil pump, the flow rate of the cooling branch path, and the opening degree of the pressure control solenoid valve based on the driving pressure demand and the cooling flow rate demand for each power terminal.

Advantages of the Invention

[0010] Additional aspects and advantages of the present application will be partly shown in the following description, partly become apparent in the following description, or be understood by implementing the present application.

Brief Description of the Drawings

[0011]

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Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present application will be described in detail. Examples of the above embodiments are shown in the drawings, and the same or similar reference numerals throughout indicate the same or similar components, or components having the same or similar functions. The embodiments described below with reference to the drawings are merely exemplary and should not be construed as interpreting or limiting the present application.

[0013] Hereinafter, with reference to the drawings, the vehicle 1000, the hydraulic system for the power train of the vehicle 1000, and its control method according to the embodiment of the present application will be described in detail.

[0014] In the hydraulic system 100 for the power train of the vehicle 1000 according to the embodiment of the first aspect of the present application, the vehicle 1000 includes one or more of a drive motor, a generator, a clutch, and a transmission, and the hydraulic system includes an oil tank 10, a main cooling oil passage m, and a plurality of cooling branch passages.

[0015] As shown in FIG. 1, one end of the main cooling oil passage m communicates with the oil tank 10, and the first oil pump 20 is provided. The first oil pump 20 pumps the oil in the oil tank 10 into the cooling branch passages. The plurality of cooling branch passages are connected to the other end of the main cooling oil passage m, and control elements independently controlled are provided in each of the plurality of cooling branch passages. The control element controls the opening and closing of the corresponding cooling branch passage, and the plurality of cooling branch passages cool one or more of the drive motor 50a, the clutch 50b, the transmission 50c, and the generator 50d.

[0016] Each cooling branch path n corresponds to the cooling of one power terminal, and the power terminal includes, but is not limited to, a drive motor 50a, a clutch 50b, a transmission 50c, and a generator 50d.

[0017] Thereby, each cooling branch path and control element form an integrated cooling valve group structure, and each solenoid valve independently opens and closes and adjusts the corresponding cooling branch path to achieve independent flow control, and independent adjustment control of the cooling flow rate of each power terminal can be realized.

[0018] In some embodiments, the cooling branch paths include at least a first cooling branch path n1, a second cooling branch path n2, a third cooling branch path n3, and a fourth cooling branch path n4. The first cooling branch path n1 cools the drive motor 50a, the second cooling branch path n2 cools the generator 50d, the third cooling branch path n3 cools the clutch 50b, and the fourth cooling branch path n4 cools the transmission 50c. Correspondingly, the control elements of each cooling branch path are the first control element 40a, the second control element 40b, the third control element 40c, and the fourth control element 40d, respectively.

[0019] Thereby, during the operation of the hybrid vehicle, there are forms in which one type of energy consumption or multiple types of energy are simultaneously involved in driving, such as the pure electric mode (the drive motor 50a is involved in driving, and the engine and the generator 50d do not operate), the parallel mode (the engine and the drive motor 50a are simultaneously involved in driving). The first cooling branch path n1, the second cooling branch path n2, the third cooling branch path n3, and the fourth cooling branch path n4 are used to cool the drive motor 50a, the generator 50d, the clutch 50b, and the transmission 50c, respectively. A cooler 30 is provided in the main cooling oil path m, and by cooling the oil in the main cooling oil path m and the cooling branch paths, not only can the cooling of each power terminal be realized, but also the functions of cooling and temperature reduction can be achieved.

[0020] The control element is a proportional control solenoid valve. Each proportional control solenoid valve receives a signal transmitted from the vehicle controller and adjusts its opening degree based on the signal. Thereby, each proportional control solenoid valve can not only control the opening and closing of the corresponding cooling branch passage, but also adjust the flow rate of each cooling branch passage as needed.

[0021] In the embodiments shown in FIGS. 1 and 2, the hydraulic system 100 further includes a driving oil passage p. The driving oil passage p is connected between the oil tank 10 and the clutch 50b. A second oil pump 60 and a pressure control solenoid valve 80 are provided in the driving oil passage p. The second oil pump 60 pumps oil into the driving oil passage p, and the driving oil passage p supplies oil to the clutch.

[0022] Thereby, the driving oil passage p is connected between the clutch and the oil tank 10, outputs pressure, and controls the opening and closing of the clutch. When it is necessary to increase the pressure of the clutch according to the driving demand pressure and the current pressure of the clutch, the pressure control solenoid valve 80 communicates the driving oil passage p with the clutch and controls the second oil pump 60 to pressurize. When it is necessary to release the pressure of the clutch, the pressure control solenoid valve 80 cuts off the communication between the driving oil passage p and the clutch and communicates the oil tank 10 with the clutch.

[0023] Also, a first safety branch passage may be drawn from the main cooling oil passage m. The first safety branch passage is located between the cooler 30 and the first oil pump 20. The first safety branch A first safety valve 91 is provided therein. The first safety valve 91 is connected to the oil tank 10 and releases pressure when the oil pressure in the main cooling oil passage m and the cooling branch passage exceeds a predetermined pressure.

[0024] Similarly, a second safety branch passage may be drawn from the driving oil passage p. The second safety branch passage is provided in the vicinity of the second oil pump 60. The second safety valve 92 is connected to the oil tank 10 and releases pressure when the oil pressure in the driving oil passage p exceeds a predetermined pressure.

[0025] In some embodiments, as shown in FIGS. 1 to 4, the hydraulic system further includes two pump motors 93, one pump motor 93 is transmission-connected to the first oil pump 20, and the other pump motor 93 is transmission-connected to the second oil pump 60. By controlling the first oil pump 20 and the second oil pump 60 respectively, the two pump motors 93 can easily and accurately control the oil pressures of the drive oil circuit p and the main cooling oil circuit m respectively.

[0026] In some other embodiments, as shown in FIG. 6, the hydraulic system further includes one pump motor 93. One end of the pump motor 93 is transmission-connected to the first oil pump 20, and the other end is transmission-connected to the second oil pump 60.

[0027] Alternatively, as shown in FIG. 5, the hydraulic system further includes one pump motor 93. One end of the pump motor 93 is sequentially transmission-connected in series to the first oil pump 20 and the second oil pump 60. By controlling both the first oil pump 20 and the second oil pump 60 with one pump motor 93, the configuration of the hydraulic system 100 is simplified and the cost of the hydraulic system 100 is reduced.

[0028] As shown in FIG. 3, the hydraulic system 100 further includes a replenishing oil circuit. The replenishing oil circuit is connected between the drive oil circuit p and the main cooling oil circuit m. When the replenishing oil circuit is in communication, the oil in the drive oil circuit p flows unidirectionally into the main cooling oil circuit m.

[0029] Thus, when the pressure control solenoid valve 80 is opened, the oil in the oil tank 10 flows through the drive oil passage p, is sent out by the second oil pump 60, and is supplied to the clutch. Also, the replenishment oil passage is blocked, and the main cooling oil passage m is not replenished using the drive oil passage p and the second oil pump 60. When the flow rate of the cooling oil passage is insufficient, it is necessary to replenish it through the drive oil passage, and the pressure control solenoid valve 80 is closed. At this time, the replenishment oil passage is switched by the action of pressure to communicate the drive oil passage p and the main cooling oil passage m. The oil in the oil tank 10 flows through the drive oil passage p and the second oil pump 60, enters the replenishment oil passage, and serves to replenish the cooling branch passage.

[0030] In the embodiment shown in FIG. 4, the replenishment oil passage includes a main replenishment oil passage q1 and a sub-adjustment oil passage q2. A pressure sliding valve 71 and a check valve 72 are provided in the main replenishment oil passage q1, and the inlet of the pressure sliding valve 71 is driven is connected to the drive oil passage p, and the outlet of the pressure sliding valve 71 is connected to the main cooling oil passage m via the check valve 72. When the pressure in the drive oil passage p is greater than the opening threshold value of the pressure sliding valve 71, the pressure sliding valve 71 is opened. One end of the sub-adjustment oil passage q2 is connected to the pressure sliding valve 71, and the other end is connected to the drive oil passage p. A pressure solenoid valve 73 is further provided in the sub-adjustment oil passage q2, and the pressure solenoid valve 73 adjusts the opening threshold value of the pressure sliding valve 71.

[0031] In this way, by controlling the pressure in the drive oil passage p, the communication and blockage of the replenishment oil passage can be realized. When the pressure in the drive oil passage p is within a certain threshold range, the pressure solenoid valve 73 is controlled to open, the sub-adjustment oil passage q2 communicates with the orifice 731 of the pressure sliding valve 71, the pressure solenoid valve 73 controls the flow rate and pressure of the orifice 731, and further controls the pressure sliding valve 71 to be in an open state or a closed state, so that the communication and blockage of the main replenishment oil passage q1 can be realized. Thus, by electrically controlling the pressure solenoid valve 73, the second oil pump 60, and the pressure sliding valve 71, the communication and blockage of the replenishment oil passage can be realized, and the responsiveness is high.

[0032] In the embodiment shown in FIG. 7, the cooling branch path further has a plurality of sub-branch paths, and a sub-branch path solenoid valve 40e or a sub-branch path throttle valve 40f is provided in each sub-branch path. Thereby, the plurality of sub-branch paths can cool different power terminals.

[0033] As shown in FIGS. 8 and 10, a vehicle 1000 according to an embodiment of the second aspect of the present application includes the hydraulic system 100 of the above embodiment, a controller 200, a power distribution module 300, a pressure calculation module 400, and a terminal flow rate calculation module 500. Hydraulic adjustment module 600 and.

[0034] The controller 200 receives driving demand information and traffic information. For example, in the conventional driving mode, accelerator pedal information and road surface gradient information are acquired, in the driving assistance mode, driver demand information and road condition prediction information are acquired, and in the automatic driving mode, acceleration demand information is acquired.

[0035] The power distribution module 300 calculates the required rotational speed information and torque information for each power terminal of the power train based on the driving demand information and the road condition information. The power terminals include one or more of a drive motor, a generator, a clutch, and a transmission.

[0036] The pressure calculation module 400 calculates the required driving pressure based on the rotational speed information and torque information of the power distribution module 300. The pressure calculation module 400 calculates the pressure demand for switching different power transmission paths based on the power transmission path of the power distribution module 300. For example, when switching from the engine series mode to the mode of driving the vehicle by the engine, the clutch engagement pressure demand is calculated.

[0037] The terminal flow rate calculation module 500 calculates the required cooling flow rate for each power terminal based on the rotational speed information, torque information of the power distribution module 300, and the temperature information of the oil in the main cooling oil path.

[0038] The hydraulic adjustment module 600 calculates the rotational speed of the first oil pump, the rotational speed of the second oil pump, the opening degree of the control element, and the opening degree of the pressure control valve based on the driving pressure demand and the cooling flow rate demand of each power terminal. In other words, based on the pressure demand of the pressure calculation module 400 and the flow rate demand aggregated by the terminal flow rate calculation module 500, it calculates the rotational speed information of the first oil pump, the opening degree information of the pressure control solenoid valve and each control element, and based on the flow rate demand aggregated by the terminal flow rate calculation module 500, it calculates the rotational speed information of the second oil pump, and based on the cooling flow rate demand of each power terminal, it calculates the flow rate information of the corresponding control element (which may be a solenoid valve). Thereby, Terminal flow meter calculation module 500 calculates the cooling flow rate demand when the efficiency of each component is the highest based on the performance of the components at different temperatures.

[0039] As shown in FIG. 9, the control method of the hydraulic system 100 for the power train of a vehicle according to the embodiment of the third aspect of the present application includes steps S1 to S3.

[0040] In S1, based on the driver demand information and the predicted road condition information, it calculates the power demand of the power train and calculates the rotational speed information and torque information required for each power terminal of the power train.

[0041] In S2, based on the rotational speed information and torque information, it calculates the flow rate demand of each power terminal, and based on the required pressure and the flow rate demand of each power terminal, it calculates the pressure demand of the hydraulic system 100.

[0042] In S3, based on the pressure demand and the flow rate demand of each power terminal, it calculates the rotational speed of the oil pump, the required pressure for each solenoid valve, and the flow rate control signal.

[0043] In this way, based on the vehicle state, the cooling requirements of each component and the total cooling flow rate requirement are calculated, an oil pump signal is output, the flow rate of the system is supplied as needed, the flow rate loss is reduced, and by controlling the cooling flow rate, each power terminal operates within a highly efficient temperature range, the cooling flow rate of each power terminal is distributed as needed, and the system efficiency is improved.

[0044] Table 1 below shows the pressures in different modes of the hydraulic system 100 and the cooling flow rates of each power terminal.

Table 1

[0045] Thus, in the pure electric mode, there is no need to supply oil to the generator 50d. In the parallel mode, the second oil pump 60 supplies oil to the drive oil path p, and the first oil pump 20 supplies coolant to the cooling branch path. In the series mode, the second oil pump 60 supplies replenishment to the main cooling oil path m via the replenishment oil path.

[0046] Also, the terms "first" and "second" are for illustrative purposes only and should not be understood as indicating or suggesting relative importance or implying the number of the indicated technical features. Thus, the features limited by "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, "a plurality" means two or more unless there is a clear and specific limitation.

[0047] In the description of this specification, descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, configurations, materials, or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of this application. In this specification, exemplary expressions of the above terms do not necessarily mean the same embodiment or example. Also, the specific features, structures, materials, or characteristics described can be appropriately combined in any one or more embodiments or examples. Also, if there is no contradiction with each other, a person skilled in the art can combine or combine different embodiments or examples described in this specification and the features of different embodiments or examples.

[0048] As described above, the embodiments of this application are shown and described. As can be understood, the above embodiments are exemplary and should not be understood as limiting this application. A person skilled in the art can make changes, modifications, exchanges, and variations to the above embodiments within the scope of this application.

Claims

1. A hydraulic system for a vehicle power train, wherein the power train includes one or more of a drive motor, a generator, a clutch, and a transmission. In the hydraulic system, it includes an oil tank, a main cooling oil passage, a plurality of cooling branch passages, a drive oil passage, and a supply oil passage. One end of the main cooling oil passage communicates with the oil tank, and a first oil pump and a cooler are provided. The plurality of cooling branch passages are connected to the other end of the main cooling oil passage. The first oil pump pumps the oil in the oil tank to the cooling branch passages. Control elements are provided in all of the plurality of cooling branch passages. The control elements control the opening and closing of the corresponding cooling branch passages. The plurality of cooling branch passages cool one or more of the drive motor, the generator, the clutch, and the transmission. The drive oil passage is connected between the oil tank and the clutch. The supply oil passage is connected between the drive oil passage and the main cooling oil passage. When the supply oil passage is in communication, the oil in the drive oil passage flows in one direction into the main cooling oil passage. A hydraulic system for a vehicle power train, characterized by the above.

2. The cooling branch passages include at least a first cooling branch passage to a fourth cooling branch passage. The first cooling branch passage cools the drive motor, the second cooling branch passage cools the generator, the third cooling branch passage cools the clutch, and the fourth cooling branch passage cools the transmission. The hydraulic system for a vehicle power train according to claim 1, characterized by the above.

3. The control element is a proportional control solenoid valve. Each proportional control solenoid valve receives a signal transmitted from a vehicle controller and adjusts its opening based on the signal. The hydraulic system for a vehicle power train according to claim 1, characterized by the above.

4. A second oil pump and a pressure control solenoid valve are provided in the drive oil passage, the second oil pump pumps oil into the drive oil passage, and the drive oil passage controls the opening and closing of the clutch. The hydraulic system for a vehicle power train according to claim 1, characterized in that.

5. The hydraulic system further includes two pump motors, one of the pump motors is transmission-connected to the first oil pump, and the other pump motor is transmission-connected to the second oil pump, or The hydraulic system further includes one pump motor, one end of the pump motor is transmission-connected to the first oil pump, and the other end is transmission-connected to the second oil pump, or The hydraulic system further includes one pump motor, one end of the pump motor is transmission-connected in series to the first oil pump and the second oil pump in sequence. The hydraulic system for a vehicle power train according to claim 4, characterized in that.

6. The supply oil passage includes a main supply oil passage and a sub-adjustment oil passage. A pressure relief valve and a check valve are provided in the main supply oil passage, an inlet of the pressure relief valve is connected to the drive oil passage, an outlet of the pressure relief valve is connected to the main cooling oil passage through the check valve, and when the pressure of the drive oil passage is greater than the opening threshold of the pressure relief valve, the pressure relief valve is opened. One end of the sub-adjustment oil passage is connected to the pressure relief valve, the other end is connected to the drive oil passage, a pressure solenoid valve is further provided in the sub-adjustment oil passage, and the pressure solenoid valve adjusts the opening threshold of the pressure relief valve. The hydraulic system for a vehicle power train according to claim 1, characterized in that.

7. The cooling branch passage further has a plurality of sub-branch passages, and a sub-branch solenoid valve or a sub-branch throttle valve is provided in each sub-branch passage. The hydraulic system for a vehicle power train according to claim 1, characterized in that.

8. The hydraulic system according to claim 4, a controller, a power distribution module, a pressure calculation module, a terminal flow rate calculation module, and a hydraulic adjustment module, wherein the controller receives driving demand information and road condition information, the power distribution module calculates rotational speed information and torque information required for each power terminal of the power train based on the driving demand information and the road condition information, and the power terminal includes one or more of the drive motor, the generator, the clutch, and the transmission, the pressure calculation module calculates the driving pressure demand based on the rotational speed information and torque information of the power distribution module, the terminal flow rate calculation module calculates the cooling flow rate demand for each power terminal based on the rotational speed information, torque information of the power distribution module, and the temperature information of the oil in the main cooling oil passage, the hydraulic adjustment module calculates the rotational speed of the first oil pump, the rotational speed of the second oil pump, the opening degree of the control element, and the opening degree of the pressure control solenoid valve based on the driving pressure demand and the cooling flow rate demand for each power terminal. A vehicle characterized by this.

9. A step of calculating rotational speed information and torque information required for each power terminal of the power train based on driving demand information and road condition information, wherein the power terminal includes one or more of the drive motor, the generator, the clutch, and the transmission, A step of calculating the driving pressure demand and the cooling flow rate demand for each power terminal based on the rotational speed information and torque information required for each power terminal, A step of calculating the rotational speed of the first oil pump, the rotational speed of the second oil pump, the flow rate of the cooling branch passage, and the opening degree of the pressure control solenoid valve based on the driving pressure demand and the cooling flow rate demand for each power terminal. A control method for a hydraulic system for a power train of a vehicle according to claim 4, characterized by including this.

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