Lubrication and cooling system and control method therefor

Abstract

A lubrication and cooling system and a control method therefor, relating to the technical field of cooling and lubrication. The lubrication and cooling system comprises first circulation piping (110), second circulation piping (120), a first oil pump (131), and a second oil pump (132). The first circulation piping (110) comprises main piping (111) and a plurality of branches communicated with the main piping (111), and at least one branch is communicated with a first motor (141); the second circulation piping (120) is communicated with a second motor (142); the first oil pump (131) is connected to the main piping (111), and the first oil pump (131) enables lubricating oil in an oil sump to pass through the main piping (111) and the branches to cool and lubricate the first motor (141) and other components, respectively; and the second oil pump (132) is connected to the second circulation piping (120), and the second oil pump (132) enables the lubricating oil in the oil sump to pass through the second circulation piping (120) to cool the second motor (142). According to the lubrication and cooling system, the rotation speeds of the oil pumps are finely adjusted, improving the operation efficiency of the whole system.

Description

Lubrication cooling system and control method thereof

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 202311047238.5 filed on August 17, 2023, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of cooling and lubrication technology, and in particular to a lubrication and cooling system and a control method thereof. Background Art

[0004] With the rapid development of new energy vehicle technology, people are increasingly demanding noise reduction from new energy vehicle drive motors. Simultaneously, as motor power density increases, the requirements for motor heat dissipation are also significantly increased. Current motor cooling solutions determine the current heat generation power of the oil-cooled motor system, and thus the target oil pump speed, based on the ambient temperature and the oil-cooled motor speed, torque, stator voltage, and stator current under current operating conditions. This only meets the requirements of single-drive motor configurations. Conventional approaches cannot precisely adjust the oil pump speeds on both sides of a dual-drive motor configuration, especially those with asymmetric oil circuit designs. This reduces the overall system efficiency and the overall vehicle economics. Summary of the Invention

[0005] The present application provides a lubrication and cooling system and a control method thereof to solve the problem of how to finely adjust the oil pump speed and improve the operating efficiency of the entire system in the case of an asymmetric oil circuit design of a dual-drive motor structure.

[0006] An embodiment of the present application provides a lubrication and cooling system, which includes: a first circulation pipeline, including a main pipeline and multiple branches that are interconnected, at least one of the branches is connected to the first motor; a second circulation pipeline, connected to the second motor; a first oil pump, connected to the main pipeline, the first oil pump uses the lubricating oil in the oil pan to cool and lubricate the first motor and other components through the main pipeline and the branch pipeline; a second oil pump, connected to the second circulation pipeline, the second oil pump uses the lubricating oil in the oil pan to cool the second motor through the second circulation pipeline.

[0007] Furthermore, the first circulation pipeline also includes a first branch and a second branch, the first branch connects the main pipeline with the first motor; the second branch connects the main pipeline with the first bearing in the reduction box.

[0008] Furthermore, the lubrication and cooling system further includes two groups of filtering devices, and the first circulation pipeline and the second circulation pipeline are grouped and connected to one group of filtering devices, and each filtering device is used to filter the lubricating oil in the oil pan.

[0009] Furthermore, the filtering device includes a coarse filter and a fine filter, and the first oil pump and the second oil pump are both located between the coarse filter and the fine filter.

[0010] Furthermore, the first circulation pipeline also includes a third branch, one end of which is communicated with the main pipeline and is located between the coarse filter and the fine filter, and the other end of the third branch is communicated with the second bearing in the reduction gearbox.

[0011] An embodiment of the present application also provides a control method for a lubrication and cooling system, which is applied to control the above-mentioned lubrication and cooling system, wherein the lubrication system also includes a radiator, and the control method includes a first control method, which includes: respectively obtaining the heating power of the first motor and the heating power of the second motor; based on the heating power of the first motor and the heating power of the second motor, respectively obtaining the cooling demand flow of the first motor and the cooling demand flow of the second motor; obtaining the first speed of the first oil pump according to the cooling demand flow and the distribution ratio of the first motor, and obtaining the second set of speeds of the second oil pump according to the cooling demand flow of the second motor; a first electric drive controller drives the first oil pump to rotate at a first speed, and a second electric drive controller drives the second oil pump to rotate at a second speed.

[0012] Furthermore, the lubrication system also includes a temperature sensor, and the control method also includes a second control method, which includes: obtaining the temperature of the lubricating oil by the temperature sensor; confirming that the lubricating oil is in a high-temperature state when the temperature exceeds a first temperature threshold; confirming that the lubricating oil is in a non-high-temperature state when the temperature does not exceed the first temperature threshold; in the high-temperature state, the first electric drive controller drives the first oil pump to rotate at a maximum speed, and the second electric drive controller drives the second oil pump to rotate at a maximum speed; in the non-high-temperature state, executing according to the first control method.

[0013] Furthermore, the lubrication system also includes a temperature sensor, and the control method also includes a third control method, which includes: obtaining the temperature of the lubricating oil by the temperature sensor; confirming that the lubricating oil is in a high temperature state when the temperature exceeds a first temperature threshold; confirming that the lubricating oil is in a medium temperature state when the temperature does not exceed the first temperature threshold and is higher than a second temperature threshold, and confirming that the lubricating oil is in a low temperature state when the temperature does not exceed the second temperature threshold; in the high temperature state, the first electric drive controller drives the first oil pump to rotate at a maximum speed, and the second electric drive controller drives the second oil pump to rotate at a maximum speed; in the medium temperature state, executing according to the first control method; in the low temperature state, the first electric drive controller drives the first oil pump to rotate at a minimum speed, and the second electric drive controller drives the second oil pump to rotate at a minimum speed.

[0014] Furthermore, the lubrication system further includes a temperature sensor, and the control method further includes a fourth control method, the fourth control method comprising: obtaining the temperature of the lubricating oil by the temperature sensor; confirming that the lubricating oil is in a high temperature state when the temperature exceeds a first temperature threshold; confirming that the lubricating oil is in a medium temperature state when the temperature does not exceed the first temperature threshold and is higher than a second temperature threshold; confirming that the lubricating oil is in a medium-low temperature state when the temperature does not exceed the second temperature threshold and is higher than a third temperature threshold; and confirming that the lubricating oil is in an ultra-low temperature state when the temperature does not exceed the third temperature threshold; in the high temperature state, the first electric drive controller drives the first oil pump to rotate at a maximum speed, and the second electric drive controller drives the second oil pump to rotate at a maximum speed; in the medium temperature state, executing the first control method; in the medium-low temperature state, the first electric drive controller drives the first oil pump to rotate at a minimum speed, and the second electric drive controller drives the second oil pump to rotate at a minimum speed. In the ultra-low temperature state, the first electric drive controller drives the first oil pump to rotate at a maximum speed, and the second electric drive controller drives the second oil pump to rotate at a maximum speed.

[0015] Furthermore, the respectively obtaining of the heating power of the first motor and the heating power of the second motor includes: obtaining the heating power of the first motor and the heating power of the second motor in real time; the first electric drive controller drives the first oil pump to rotate at a first speed, and the second electric drive controller drives the second oil pump to rotate at a second speed includes: the first electric drive controller drives the first oil pump to rotate at the first speed in real time, and the second electric drive controller drives the second oil pump to rotate at the second speed in real time.

[0016] The present application provides a lubrication and cooling system, which includes a first circulation pipeline, a second circulation pipeline, a first oil pump and a second oil pump. The first circulation pipeline includes a main pipeline and multiple branches that are interconnected, at least one branch is connected to the first motor; the second circulation pipeline is connected to the second motor; the first oil pump is connected to the main pipeline, and the first oil pump cools and lubricates the lubricating oil in the oil pan through the main pipeline and the branch pipeline respectively; the second oil pump is connected to the second circulation pipeline, and the second oil pump cools the second motor through the second circulation pipeline. For the dual-motor electric drive assembly, two sets of circulation pipelines are used, and each circulation pipeline is connected to an independent oil pump. Taking into account the different cooling requirements of each motor in the dual-motor electric drive assembly, and the cooling and lubrication paths of each circulation pipeline are also different, the oil pumping volume of the oil pump in each circulation pipeline is precisely controlled according to different needs, thereby increasing the proportion of electric drive working in the high-efficiency range, and thus improving the overall efficiency of the electric drive. At the same time, the first circulation pipeline is branched, and the branches of the first circulation pipeline are used to actively cool and lubricate other components, which helps to extend the service life of other components and improve the operating efficiency of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG1 is a schematic structural diagram of a lubrication and cooling system provided in an embodiment of the present application;

[0018] FIG2 is a schematic structural diagram of another lubrication and cooling system provided in an embodiment of the present application;

[0019] FIG3 is a schematic structural diagram of another lubrication and cooling system provided in an embodiment of the present application;

[0020] FIG4 is a flow chart of a control method provided in an embodiment of the present application;

[0021] FIG5 is a flow chart of another control method provided in an embodiment of the present application;

[0022] FIG6 is a flow chart of another control method provided in an embodiment of the present application;

[0023] FIG7 is a flow chart of another control method provided in an embodiment of the present application;

[0024] FIG8 is a flow chart of another control method provided in an embodiment of the present application.

[0025] Description of Reference Numerals

[0026] 100. Lubrication and cooling system; 110. First circulation pipeline; 111. Main pipeline; 112. First branch pipeline; 113. Second branch pipeline; 114. Third branch pipeline; 120. Second circulation pipeline; 130. Oil pump; 131. First oil pump; 132. Second oil pump; 140. Motor; 141. First motor; 142. Second motor; 150. Oil pan; 160. Filter device; 161. Coarse filter; 162. Fine filter; 170. Radiator; 180. Electric drive controller; 181. First electric drive controller; 182. Second electric drive controller; 190. Gearbox; 191. First bearing; 192. Second bearing. Modes for Carrying Out the Invention

[0027] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. The specific embodiments described here are only used to explain this application and are not used to limit this application.

[0028] The various specific technical features described in the specific embodiments may be combined in any suitable manner, unless they are inconsistent. For example, different embodiments and technical solutions may be formed by combining different specific technical features. To avoid unnecessary repetition, the various possible combinations of the specific technical features in this application will not be described separately.

[0029] In the following description, the terms "first, second, ..." are used solely to distinguish different objects and do not imply any similarities or connections between the objects. The directions "above," "below," "outside," and "inside" refer to directions during normal use. The directions "left" and "right" refer to the left-right directions shown in the corresponding schematic diagrams, which may or may not be the left-right directions during normal use.

[0030] It should be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising that element. The term "connected," unless otherwise specified, includes both direct and indirect connections.

[0031] In a specific embodiment, the lubrication and cooling system includes a first circulation line, a second circulation line, a first oil pump, and a second oil pump. It is suitable for cooling and lubricating any type of automotive electric drive assembly. For example, the lubrication and cooling system can be used for cooling and lubricating the electric drive assembly of a family sedan; for example, the lubrication and cooling system can be used for cooling and lubricating the electric drive assembly of a commercial bus. Its control method is similar to the control method of the lubrication and cooling system described above. For ease of explanation, the following description uses the lubrication and cooling system's application to cooling and lubricating the dual electric drive assembly of a family sedan as an example.

[0032] 1 , the lubrication and cooling system 100 includes a first circulation line 110 , a second circulation line 120 , an oil pump 130 , and a motor 140 . The oil pump 130 includes a first oil pump 131 and a second oil pump 132 , and the motor 140 includes a first motor 141 and a second motor 142 .

[0033] The first circulation pipeline 110 includes a main pipeline 111 and multiple branches that are interconnected, at least one of which is connected to the first motor 141; the first oil pump 131 is connected to the main pipeline 111, and the first oil pump 131 cools and lubricates the lubricating oil in the oil pan 150 through the main pipeline 111 and the branches to cool and lubricate the first motor 141 and other components. Specifically, for a dual-motor electric drive assembly, it is necessary to cool and lubricate two motors, namely the first motor 141 and the second motor 142. The first circulation pipeline 110 includes a main pipeline 111 and multiple branches. The first oil pump 131 is set in the main pipeline 111, and the rotation of the first oil pump 131 is controlled by the first electric drive controller 181 in the electric drive controller 180. The specific rotation speed of the first oil pump 131 is related to the heat dissipation requirement of the first motor 141. The specific calculation method is described in detail later. The first oil pump 131 rotates to draw lubricating oil from the oil pan 150 into the main line 111. The lubricating oil in the main line 111 is then cooled by the radiator 170. The cooled lubricating oil is then delivered to the corresponding cooling and lubrication positions through various branches. At least one branch is connected to the first motor 141. The lubricating oil from the main line 111 lubricates the first motor 141 through the branch and then flows back to the oil pan 150 under the action of gravity. The remaining branches can be connected to the reduction gearbox 190 to cool and lubricate the bearings of the reduction gearbox 190. It should be noted that the flow rates of the various branches are different, and the distribution ratio can be adjusted according to demand. The specific distribution ratio is not limited. For example, the flow rates of the various branches can be proportionally distributed according to the cross-sectional area of ​​the branches. If the ratio of the cross-sectional areas is 4 to 1, the flow rates can also be roughly considered to be 4 to 1.

[0034] The second circulation line 120 is in communication with the second motor 142, and the second oil pump 132 is connected to the second circulation line 120. The second oil pump 132 draws lubricating oil from the oil pan 150 through the second circulation line 120 to cool the second motor 142. Specifically, the cooling and lubrication method of the second circulation line 120 is the same as that of the first circulation line 110. The second circulation line 120 only needs to be in communication with the second motor 142. The second electric drive controller 182 in the electric drive controller 180 controls the rotation of the second oil pump 132. The rotation of the second oil pump 132 draws lubricating oil from the oil pan 150 into the second circulation line 120. The lubricating oil in the second circulation line 120 is then cooled by the radiator 170. The cooled lubricating oil is then delivered to the second motor 142 to cool the second motor 142, and then flows back to the oil pan 150 under the action of gravity.

[0035] The following describes in detail the rotational speeds of the first oil pump 131 and the second oil pump 132. First, the heating power of the motor 140 is related to the torque, rotational speed, and efficiency of the motor 140. The heating power of the first motor 141 is PQ1, where T1 is the torque of the first motor 141, n1 is the rotational speed of the first motor 141, and η1 is the efficiency of the first motor 141. After knowing the heating power of the first motor 141, based on the heat dissipation power of the radiator 170, the cooling demand flow Q1 under the heating power of the first motor 141 can be calculated. Further considering that the flow provided by the first oil pump 131 needs to meet the cooling and lubrication of the first motor 141 and the reducer 190, the flow of the first oil pump 131 should be greater than Q1. The ratio of the flow required by the first motor 141 to the flow of the main line 111 in the first circulation pipeline 110 is δ. According to the formula, it can be calculated that the speed of the first oil pump 131 should be, Vg1 is the displacement of the first oil pump 131, and η3 is the efficiency of the first oil pump 131. For example, the cooling flow demand of the first motor 141 accounts for 0.8, and the cooling and lubrication flow demand of the reducer 190 accounts for 0.2, then δ is 0.8, the cooling flow demand of the first motor 141 is Q1, and the cooling and lubrication flow demand of the reducer 190 is Q1 / 4, and the speed of the first oil pump 131 should be. Similarly, the heat generation power of the second motor 142 is PQ2, T2 is the torque of the second motor 142, n2 is the speed of the second motor 142, and η2 is the efficiency of the second motor 142. Based on the heat dissipation power of the radiator 170, the required cooling flow rate Q2 under the heat generation power of the second motor 142 can be calculated. The second circulation pipeline 120 only needs to cool the second motor 142. According to the formula, the speed of the second oil pump 132 can be calculated as follows: Vg2 is the displacement of the second oil pump 132, and η4 is the efficiency of the second oil pump 132.

[0036] The present application provides a lubrication and cooling system, which includes a first circulation pipeline, a second circulation pipeline, a first oil pump and a second oil pump. The first circulation pipeline includes a main pipeline and multiple branches that are interconnected, at least one branch is connected to the first motor; the second circulation pipeline is connected to the second motor; the first oil pump is connected to the main pipeline, and the first oil pump cools and lubricates the lubricating oil in the oil pan through the main pipeline and the branch pipeline respectively; the second oil pump is connected to the second circulation pipeline, and the second oil pump cools the second motor through the second circulation pipeline. For the dual-motor electric drive assembly, two sets of circulation pipelines are used, and each circulation pipeline is connected to an independent oil pump. Taking into account the different cooling requirements of each motor in the dual-motor electric drive assembly, and the cooling and lubrication paths of each circulation pipeline are also different, the oil pumping volume of the oil pump in each circulation pipeline is precisely controlled according to different needs, thereby increasing the proportion of electric drive working in the high-efficiency range, and thus improving the overall efficiency of the electric drive. At the same time, the first circulation pipeline is branched, and the branches of the first circulation pipeline are used to actively cool and lubricate other components, which helps to extend the service life of other components and improve the operating efficiency of the entire system.

[0037] In some embodiments, as shown in FIG1 , the first circulation pipeline 110 further includes a first branch 112 and a second branch 113 . The first branch 112 connects the main pipeline 111 with the first motor 141 ; the second branch 113 connects the main pipeline 111 with the first bearing 171 in the reduction box 190 . Specifically, the first circulation pipeline 110 includes a main line 111, a first branch line 112 and a second branch line 113. The first oil pump 131 sucks lubricating oil from the oil pan 150 into the main line 111, and then flows from the main line 111 into the first branch line 112 and the second branch line 113 respectively. The first branch line 112 is connected to the first motor 141, and the first motor 141 is cooled by the lubricating oil in the first branch line 112. The second branch line 113 is connected to the first bearing 171 in the reducer 190, and the first bearing 171 in the reducer 190 is cooled and lubricated by the second branch line 113. The first bearing 171 here can be understood as a single bearing or a plurality of bearings. For example, the first bearing 171 can be all bearings except the needle roller bearings in the reducer 190. All bearings in the reducer 190 except the needle roller bearings are actively lubricated through the second branch line 113, and then return to the bottom of the reducer 190 by gravity. The specific distribution ratio of the flow in the first branch 112 and the second branch 113 is not limited. The distribution flow can be controlled according to the cross-sectional area of ​​the first branch 112 and the second branch 113, or by adding a control valve to control the distribution flow. For example, 80% of the lubricating oil in the main branch 111 flows into the first branch 112, and 20% of the lubricating oil in the main branch 111 flows into the second branch 113.

[0038] In some embodiments, as shown in FIG2 , to reduce metal powder and impurities in the lubricating oil, the lubrication and cooling system 100 further includes two sets of filtering devices 160. The first circulation pipeline 110 and the second circulation pipeline 120 are connected to a set of filtering devices 160, each of which is used to filter the lubricating oil in the oil pan 150. Specifically, the first circulation pipeline 110 is connected to the filtering devices 160, and the lubricating oil containing metal powder and impurities in the oil pan 150 enters the first circulation pipeline 110. As it passes through the filtering devices 160, the lubricating oil containing metal powder and impurities is filtered by the filtering devices 160. The filtered lubricating oil is then passed through the first circulation pipeline 110 through various branches to cool and lubricate the first motor 141 and the first bearing 191 of the reduction gearbox. Any device or structure capable of filtering lubricating oil containing metal powder and impurities is acceptable, and the specific location of the filtering devices 160 is not limited. Illustratively, filter device 160 includes a filter consisting of a cylindrical body, a stainless steel filter screen, a sewage discharge section, a transmission device, and an electrical control unit. Lubricating oil containing metal powder and impurities passes through the filter screen cartridge, where the impurities are trapped. When cleaning is necessary, the removable filter cartridge is simply removed, processed, and reinstalled, making operation and maintenance convenient. To further enhance filtering effectiveness and prevent damage to related equipment caused by metal powder and impurities, filter device 160 includes a coarse filter 161 and a fine filter 162, with the first oil pump 131 positioned between coarse filter 161 and fine filter 162. Lubricating oil containing metal powder and impurities in the oil pan 150 enters the first circulation pipeline 110. When passing through the coarse filter 161, the coarse filter 161 can intercept and filter out larger impurities. The lubricating oil then passes through the first oil pump 131 and the fine filter 162. The fine filter 162 can filter the lubricating oil finely, removing fine impurities and colloids with a diameter of 0.001 mm or more. The filtered lubricating oil then flows through the radiator 170 to dissipate heat, protecting the radiator 170 and preventing the lubricating oil containing metal powder and impurities from clogging the first oil pump 131 and radiator 170. Finally, the filtered lubricating oil is used through the first circulation pipeline 110 to cool and lubricate the first motor 141 and the first bearing 191 of the reduction gearbox. Similarly, the second circulation pipeline 120 is also connected to the same filtering device 160, which serves the same purpose and will not be further described here.

[0039] In some embodiments, as shown in FIG3 , the first circulation pipeline 110 further includes a third branch 114, one end of the third branch 114 is in communication with the main pipeline 111, and is located between the coarse filter 161 and the fine filter 162, and the other end of the third branch 114 is in communication with the second bearing 172 in the reduction gearbox 190. Specifically, considering that some components have high requirements for the quality of lubricating oil, impurities in the lubricating oil may cause wear of the components, while some components have general requirements for the quality of lubricating oil, and fine impurities will not affect the components, in order to better improve efficiency, some components can be cooled and lubricated after being filtered by the coarse filter 161. Therefore, the first circulation pipeline 110 further includes a third branch 114, one end of the third branch 114 is located between the coarse filter 161 and the fine filter 162, and the first oil pump 131 pumps the lubricating oil from the oil pan to the oil pan. The oil sucked in from 150 flows into the main line 111, part of the lubricating oil flows into the third branch 114 through the coarse filter 161, and most of the remaining lubricating oil flows into the fine filter 162 through the coarse filter 161. The third branch 114 is connected to the second bearing 172 in the reducer 190, and the second bearing 172 in the reducer 190 is cooled and lubricated through the third branch 114. The second bearing 172 here can be understood as a single bearing or a plurality of bearings. For example, the second bearing 172 can be a needle roller bearing in the reducer 190.

[0040] This embodiment provides a control method for a lubrication and cooling system, which is applicable to the lubrication system shown in any one of Figures 1 to 3. Please refer to Figure 4, which is a flow chart of a control method for a lubrication and cooling system provided in an embodiment of the present application. The control method includes a first control method, the flow of which is as follows:

[0041] Step S10: obtaining the heating power of the first motor and the heating power of the second motor respectively.

[0042] Specifically, the control system calculates the heat generation power PQ1 of the first motor based on relevant information such as the torque, speed, and efficiency of the first motor, where T1 is the torque of the first motor, n1 is the speed of the first motor, and η1 is the efficiency of the first motor. Based on relevant information such as the torque, speed, and efficiency of the second motor, the control system calculates the heat generation power PQ2 of the second motor, where T2 is the torque of the second motor, n2 is the speed of the second motor, and η2 is the efficiency of the second motor.

[0043] In step S20 , based on the heating power of the first motor and the heating power of the second motor, a cooling demand flow rate of the first motor and a cooling demand flow rate of the second motor are obtained respectively.

[0044] Specifically, the control system can obtain the cooling demand flow Q1 under the heating power of the first motor based on the heating power PQ1 of the first motor and the heat dissipation power of the radiator. The control system can obtain the cooling demand flow Q2 under the heating power of the first motor based on the heating power PQ2 of the second motor and the heat dissipation power of the radiator.

[0045] Step S30 , obtaining a first rotational speed of the first oil pump according to the cooling flow required by the first motor and the distribution ratio, and obtaining a second rotational speed of the second oil pump according to the cooling flow required by the second motor.

[0046] Specifically, after obtaining the cooling demand flow rate Q1 at the heating power of the first motor, the flow rate provided by the first oil pump must meet the cooling and lubrication needs of the first motor and the reduction gearbox. Therefore, the flow rate of the first oil pump should be greater than Q1. The ratio of the flow rate required by the first motor to the flow rate of the main line in the first circulation pipeline is δ. The system can calculate the speed of the first oil pump according to the formula: Vg1 is the displacement of the first oil pump, and η3 is the efficiency of the first oil pump. After obtaining the cooling demand flow rate Q2 at the heating power of the second motor, the system can calculate the speed of the second oil pump according to the formula: Vg2 is the displacement of the second oil pump 132, and η4 is the efficiency of the second oil pump.

[0047] In step S40 , the first electric drive controller drives the first oil pump to rotate at a first speed, and the second electric drive controller drives the second oil pump to rotate at a second speed.

[0048] Specifically, after the control system obtains the speed of the first oil pump and the speed of the second oil pump, the first electric drive controller sends a first control instruction, and the first oil pump rotates at the first speed in response to the first control instruction. The second electric drive controller sends a second control instruction, and the second oil pump rotates at the second speed in response to the second control instruction.

[0049] In some embodiments, as shown in FIG5 , FIG5 is a flow chart of another control method for a lubrication and cooling system provided by an embodiment of the present application. The control method includes a second control method, and the flow is as follows:

[0050] Step S50: obtaining the temperature of the lubricating oil by a temperature sensor.

[0051] Specifically, the number of temperature sensors can be one or more. Multiple temperature sensors can be provided for more accurate temperature detection. The specific location of the temperature sensor is not limited. For example, the temperature sensor can be provided in the main pipeline between the coarse filter and the fine filter, or in the oil pan. The temperature of the lubricating oil is obtained through the temperature sensor.

[0052] Step S60: When the temperature exceeds the first temperature threshold, confirm that the lubricating oil is in a high temperature state; when the temperature does not exceed the first temperature threshold, confirm that the lubricating oil is in a non-high temperature state.

[0053] Specifically, a first temperature threshold T0 is set, and the specific value can be determined according to actual conditions. For example, if the first temperature threshold T0 is 80 degrees Celsius, and the lubricating oil temperature measured by the temperature sensor exceeds 80 degrees Celsius, the control system determines that the lubricating oil is in a high temperature state; if the lubricating oil temperature measured by the temperature sensor does not exceed 80 degrees Celsius, the control system determines that the lubricating oil is in a non-high temperature state.

[0054] Step S70 includes step S71 or step S72. In step S71, under high temperature state, the first electric drive controller drives the first oil pump to rotate at the maximum speed, and the second electric drive controller drives the second oil pump to rotate at the maximum speed; in step S72, under non-high temperature state, the first control method is executed.

[0055] Specifically, considering that the lubricating oil is in a high temperature state, it is not possible to effectively cool the first motor, the second motor, the bearings of the reduction gearbox and other related components, so it is necessary to speed up the cooling of the lubricating oil itself.

[0056] If the control system determines that the lubricating oil is at a high temperature, the first electric drive controller sends a control instruction to the first oil pump, causing the first oil pump to rotate at its maximum speed. Similarly, the second electric drive controller sends a control instruction to the second oil pump, causing the second oil pump to rotate at its maximum speed, thereby accelerating the cooling of the lubricating oil and the motor. In a non-high temperature state, steps 10, 20, 30, and 40 of the first control method are executed and will not be further described here.

[0057] In some embodiments, as shown in FIG6 , FIG6 is a flow chart of another control method for a lubrication and cooling system provided in an embodiment of the present application. The control method includes a third control method, and the flow is as follows:

[0058] Step S50: obtaining the temperature of the lubricating oil by a temperature sensor.

[0059] The details have been described above and will not be repeated here.

[0060] Step S80, when the temperature exceeds the first temperature threshold, confirm that the lubricating oil is in a high temperature state; when the temperature does not exceed the first temperature threshold and is higher than the second temperature threshold, confirm that the lubricating oil is in a medium temperature state; when the temperature does not exceed the second temperature threshold, confirm that the lubricating oil is in a low temperature state.

[0061] Specifically, a first temperature threshold and a second temperature threshold are set, and the specific numerical values ​​can be determined according to actual conditions. For example, the first temperature threshold is 80 degrees Celsius, and the second temperature threshold is 30 degrees Celsius. If the lubricating oil temperature measured by the temperature sensor exceeds 80 degrees Celsius, the control system determines that the lubricating oil is in a high temperature state; if the lubricating oil temperature measured by the temperature sensor does not exceed 80 degrees Celsius but is higher than 30 degrees Celsius, the control system determines that the lubricating oil is in a medium temperature state; if the lubricating oil temperature measured by the temperature sensor does not exceed 30 degrees Celsius, the control system determines that the lubricating oil is in a low temperature state.

[0062] Step S90 includes step S91 or step S92 or step S93. In step S91, under high temperature conditions, the first electric drive controller drives the first oil pump to rotate at the maximum speed, and the second electric drive controller drives the second oil pump to rotate at the maximum speed; in step S92, under medium temperature conditions, the first control method is executed; in step S93, under low temperature conditions, the first electric drive controller drives the first oil pump to rotate at the minimum speed, and the second electric drive controller drives the second oil pump to rotate at the minimum speed.

[0063] Specifically, the control method under high temperature conditions has been described above and will not be repeated here. Considering that lubricating oil has a good cooling effect under low temperature conditions, there is no need to increase the flow rate of lubricating oil, thereby saving energy consumption. Under medium temperature conditions, steps 100, 200, 300 and 400 in the first control method are executed, and no further details are given here. Under low temperature conditions, the first electric drive controller sends a control instruction to the first oil pump, and the first oil pump receives the control instruction and rotates at the minimum speed. The numerical value of the minimum speed is not limited. For example, the normal temperature lubrication flow demand of the electric drive is obtained based on simulation and lubrication tests: n0 ≥ 800 rpm, that is, the minimum speed of the first oil pump is 800 revolutions per second. Similarly, the second oil pump also rotates at the minimum speed.

[0064] In some embodiments, as shown in FIG7 , FIG7 is a flow chart of another control method for a lubrication and cooling system provided in an embodiment of the present application. The control method includes a fourth control method, and the flow is as follows:

[0065] Step S50: obtaining the temperature of the lubricating oil by a temperature sensor.

[0066] The details have been described above and will not be repeated here.

[0067] Step S100, when the temperature exceeds the first temperature threshold, confirm that the lubricating oil is in a high temperature state; when the temperature does not exceed the first temperature threshold and is higher than the second temperature threshold, confirm that the lubricating oil is in a medium temperature state; when the temperature does not exceed the second temperature threshold and is higher than the third temperature threshold, confirm that the lubricating oil is in a medium-low temperature state; when the temperature does not exceed the third temperature threshold, confirm that the lubricating oil is in an ultra-low temperature state.

[0068] Specifically, a first temperature threshold, a second temperature threshold and a third temperature threshold are set. The specific numerical values ​​can be determined according to actual conditions. For example, the first temperature threshold is 80 degrees Celsius, the second temperature threshold is 30 degrees Celsius, and the third temperature threshold is 0 degrees Celsius. If the lubricating oil temperature measured by the temperature sensor exceeds 80 degrees Celsius, the control system determines that the lubricating oil is in a high temperature state; if the lubricating oil temperature measured by the temperature sensor does not exceed 80 degrees Celsius but is higher than 30 degrees Celsius, the control system determines that the lubricating oil is in a medium temperature state; if the lubricating oil temperature measured by the temperature sensor does not exceed 30 degrees Celsius but is higher than 0 degrees Celsius, the control system determines that the lubricating oil is in a medium-low temperature state; if the lubricating oil temperature measured by the temperature sensor does not exceed 0 degrees Celsius, the control system determines that the lubricating oil is in an ultra-low temperature state.

[0069] Step S110 includes step S111 or step S112 or step S113 or step S114. In step S111, under high temperature conditions, the first electric drive controller drives the first oil pump to rotate at the maximum speed, and the second electric drive controller drives the second oil pump to rotate at the maximum speed. In step S112, under medium temperature conditions, the first control method is executed. In step S113, under medium-low temperature conditions, the first electric drive controller drives the first oil pump to rotate at the minimum speed, and the second electric drive controller drives the second oil pump to rotate at the minimum speed. In step S114, under ultra-low temperature conditions, the first electric drive controller drives the first oil pump to rotate at the maximum speed, and the second electric drive controller drives the second oil pump to rotate at the maximum speed.

[0070] Specifically, the control methods for high and medium temperature conditions have been described above and will not be repeated here. Considering that lubricating oil has a good cooling effect at medium and low temperatures, there is no need to increase the lubricating oil flow rate, thereby saving energy. In medium and low temperature conditions, the first electric drive controller sends a control command to the first oil pump. Upon receiving the control command, the first oil pump rotates at the minimum speed. The numerical value of the minimum speed is not limited. For example, the normal temperature lubrication flow requirement of the electric drive is determined based on simulation and lubrication testing: n0 ≥ 800 rpm, meaning that the minimum speed of the first oil pump is 800 revolutions per second. Similarly, the second oil pump also rotates at the minimum speed. In ultra-low temperature conditions, the viscosity of the lubricating oil gradually increases as the oil temperature drops, and the motor load gradually increases. At this time, the cooling motor defines the oil pump speed based on the maximum current I0. The maximum current I0 can be corrected based on previous calibration. I0 is set based on the controller's overcurrent protection current and the long-term allowable operating current of the water pump. In the ultra-low temperature state, the first electric drive controller sends a control instruction to the first oil pump, and the first oil pump receives the control instruction and rotates at the maximum speed according to the maximum current I0. Similarly, the second electric drive controller sends a control instruction to the second oil pump, and the second oil pump receives the control instruction and rotates at the maximum speed according to the maximum current I0.

[0071] In some embodiments, FIG8 is a flow chart of another method for controlling a lubrication and cooling system according to an embodiment of the present application. Based on FIG4 , step S10 in FIG8 includes:

[0072] Step S11 , obtaining the heating power of the first motor and the heating power of the second motor in real time.

[0073] Specifically, to improve the cooling effect of the first and second motors, the speeds of the first and second oil pumps need to be adjusted in real time. Therefore, the control system needs to obtain the heating power PQ1 of the first motor and the heating power PQ2 of the second motor in real time based on relevant information such as the torque, speed, and efficiency of the motors. Real-time here can be understood as uninterrupted acquisition, for example, obtaining data once per second or twice per second.

[0074] Based on FIG4 , step S40 in FIG8 includes the first electric drive controller driving the first oil pump to rotate at a first speed in real time, and the second electric drive controller driving the second oil pump to rotate at a second speed in real time.

[0075] Specifically, based on the real-time adjustment of the heating power PQ1 of the first motor and the heating power PQ2 of the second motor, the real-time cooling demand flow Q1 under the heating power of the first motor and the cooling demand flow Q2 under the heating power of the second motor are obtained, so that the speed of the first oil pump and the speed of the second oil pump are obtained according to the demand flow Q1 and the demand flow Q2. After the control system obtains the speed of the first oil pump and the speed of the second oil pump, the first electric drive controller sends a first control instruction in real time, and the first oil pump rotates at the first speed in response to the first control instruction. The second electric drive controller sends a second control instruction in real time, and the second oil pump rotates at the second speed in response to the second control instruction.

[0076] The above description is merely a preferred embodiment of the present application and is not intended to limit the scope of protection of the present application.

Claims

1. A lubrication cooling system, wherein: The system comprises: A first circulation pipeline, comprising a main pipeline and a plurality of branches that are interconnected, at least one of the branches being connected to the first motor; A second circulation pipeline is connected to the second motor; a first oil pump connected to the main line, the first oil pump cools and lubricates the first motor and other components through the main line and the branch line respectively using the lubricating oil in the oil pan; The second oil pump is connected to the second circulation pipeline, and the second oil pump cools the second motor through the second circulation pipeline using the lubricating oil in the oil pan.

2. The lubrication and cooling system according to claim 1, wherein: The first circulation pipeline also includes a first branch and a second branch, the first branch connects the main pipeline with the first motor; the second branch connects the main pipeline with the first bearing in the reduction box.

3. The lubrication and cooling system according to claim 1 or 2, wherein: The lubrication cooling system further includes two groups of filtering devices. The first circulation pipeline and the second circulation pipeline are grouped and connected to one group of filtering devices. Each of the filtering devices is used to filter the lubricating oil in the oil pan.

4. The lubrication and cooling system according to claim 3, wherein: The filtering device includes a coarse filter and a fine filter, and the first oil pump and the second oil pump are both located between the coarse filter and the fine filter.

5. The lubrication and cooling system according to claim 4, wherein: The first circulation pipeline also includes a third branch, one end of which is communicated with the main pipeline and is located between the coarse filter and the fine filter, and the other end of the third branch is communicated with the second bearing in the reduction box.

6. A control method for a lubrication cooling system, wherein: The control method is applied to control the lubrication and cooling system according to any one of claims 1 to 5, wherein the lubrication system further comprises a radiator, and the control method comprises a first control method, wherein the first control method comprises: respectively obtaining the heating power of the first motor and the heating power of the second motor; Based on the heating power of the first motor and the heating power of the second motor, respectively obtaining the cooling demand flow rate of the first motor and the cooling demand flow rate of the second motor; Obtaining a first rotation speed of the first oil pump according to the cooling demand flow rate and the distribution ratio of the first motor, and obtaining a second rotation speed of the second oil pump according to the cooling demand flow rate of the second motor; The first electric drive controller drives the first oil pump to rotate at a first speed, and the second electric drive controller drives the second oil pump to rotate at a second speed.

7. The control method according to claim 6, wherein: The lubrication system further includes a temperature sensor, and the control method further includes a second control method, wherein the second control method includes: acquiring the temperature of the lubricating oil by the temperature sensor; When the temperature exceeds a first temperature threshold, it is confirmed that the lubricating oil is in a high temperature state; when the temperature does not exceed the first temperature threshold, it is confirmed that the lubricating oil is in a non-high temperature state; In the high temperature state, the first electric drive controller drives the first oil pump to rotate at a maximum speed, and the second electric drive controller drives the second oil pump to rotate at a maximum speed; in the non-high temperature state, the first control method is executed.

8. The control method according to claim 6, wherein: The lubrication system further includes a temperature sensor, and the control method further includes a third control method, and the third control method includes: acquiring the temperature of the lubricating oil by the temperature sensor; When the temperature exceeds a first temperature threshold, it is confirmed that the lubricating oil is in a high temperature state; when the temperature does not exceed the first temperature threshold and is higher than a second temperature threshold, it is confirmed that the lubricating oil is in a medium temperature state; and when the temperature does not exceed the second temperature threshold, it is confirmed that the lubricating oil is in a low temperature state; In the high temperature state, the first electric drive controller drives the first oil pump to rotate at the maximum speed, and the second electric drive controller drives the second oil pump to rotate at the maximum speed; in the medium temperature state, the first control method is executed; in the low temperature state, the first electric drive controller drives the first oil pump to rotate at the minimum speed, and the second electric drive controller drives the second oil pump to rotate at the minimum speed.

9. The control method according to claim 6, wherein: The lubrication system further includes a temperature sensor, and the control method further includes a fourth control method, which includes: acquiring the temperature of the lubricating oil by the temperature sensor; When the temperature exceeds a first temperature threshold, it is confirmed that the lubricating oil is in a high temperature state; when the temperature does not exceed the first temperature threshold and is higher than a second temperature threshold, it is confirmed that the lubricating oil is in a medium temperature state; when the temperature does not exceed the second temperature threshold and is higher than a third temperature threshold, it is confirmed that the lubricating oil is in a medium-low temperature state; when the temperature does not exceed the third temperature threshold, it is confirmed that the lubricating oil is in an ultra-low temperature state; In the high temperature state, the first electric drive controller drives the first oil pump to rotate at the maximum speed, and the second electric drive controller drives the second oil pump to rotate at the maximum speed; in the medium temperature state, the first control method is executed; in the medium and low temperature state, the first electric drive controller drives the first oil pump to rotate at the minimum speed, and the second electric drive controller drives the second oil pump to rotate at the minimum speed; in the ultra-low temperature state, the first electric drive controller drives the first oil pump to rotate at the maximum speed, and the second electric drive controller drives the second oil pump to rotate at the maximum speed.

10. The control method according to claim 6, wherein: The obtaining the heating power of the first motor and the heating power of the second motor respectively comprises: acquiring the heating power of the first motor and the heating power of the second motor in real time; The first electric drive controller drives the first oil pump to rotate at a first speed, and the second electric drive controller drives the second oil pump to rotate at a second speed, comprising: The first electric drive controller drives the first oil pump to rotate at a first speed in real time, and the second electric drive controller drives the second oil pump to rotate at a second speed in real time.

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