A lubricating and cooling device and control method for a power assembly of an electric vehicle

Abstract

The application discloses a lubricating and cooling device and a control method of an electric vehicle power assembly, which comprises a sensor, a hydraulic device and an electronic control unit; temperature sensors and flow sensors are arranged on lubricating and cooling points of the power assembly; the hydraulic device comprises an oil tank, a coarse filter, an electronic oil pump, a fine filter, a radiator and an electromagnetic valve; the electronic oil pump, the electromagnetic valve, the temperature sensors and the flow sensors are connected with the electronic control unit; the application has simple structure and can effectively meet different lubricating and cooling demands of different lubricating and cooling points at the same time; the lubricating and cooling demand flow under various working conditions is detected and compensated in real time, the reliability of lubricating and cooling of the electric vehicle power assembly is improved, and the performance of the electric vehicle is improved.

Description

Technical Field

[0001] This invention belongs to the field of vehicle technology, specifically relating to a lubrication and cooling device and control method for an electric vehicle powertrain. Background Technology

[0002] An electric drive assembly consists of a motor, a motor controller, and a reducer. The motor and motor controller require cooling, while the reducer requires both cooling and lubrication. Proper cooling and lubrication are fundamental prerequisites for ensuring the performance of an electric drive system. However, the three components have different requirements for coolant temperature. For example, the motor and controller are generally water-cooled, with temperatures typically between 30-75℃; the reducer is lubricated and cooled by oil, with temperatures typically between 90-120℃. Using multiple independent cooling systems results in low system cooling efficiency, high cost, and hinders integrated design.

[0003] Therefore, designing an integrated oil cooling system that meets the cooling and lubrication requirements of various components with different operating temperatures using the same cooling medium, and using control algorithms to achieve the highest economic efficiency under different operating conditions, is a key technology for realizing the high integration and high torque density design of electric drive assemblies. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a simple and highly reliable lubrication and cooling device and control method for an electric vehicle powertrain. By timely mixing two types of hydraulic oil—cooled hydraulic oil and uncooled hydraulic oil—the temperature (viscosity) of the hydraulic oil is altered, thereby satisfying the different operating temperature requirements of the same hydraulic oil for components such as the motor, controller, and reducer.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is:

[0006] A lubrication and cooling control method for an electric vehicle powertrain is disclosed, which utilizes the lubrication and cooling device of the electric vehicle powertrain. The lubrication and cooling device includes temperature sensor I, temperature sensor II, temperature sensor III, flow sensor I, flow sensor II, flow sensor III, a hydraulic device, and an electronic control unit. The hydraulic device includes an oil tank, a coarse filter, an electronic oil pump, a fine filter, a radiator, and solenoid valves I, II, and III. The oil tank is sequentially connected to the coarse filter, the electronic oil pump, and the fine filter to form a hydraulic oil branch AA. After continuing to connect to the radiator, hydraulic oil branches BB, CC, and DD are established respectively. The hydraulic oil temperature at these three locations is lower than that at hydraulic oil branch AA because it has been cooled by the radiator. Hydraulic oil branch DD, after connecting to solenoid valve I, mainly forms hydraulic oil branch EE; hydraulic oil branch BB, after connecting to solenoid valve III, mainly forms hydraulic oil branch GG; hydraulic oil branch AA, after connecting to solenoid valve II, mainly forms hydraulic oil branch FF; hydraulic oil branch DD connects to port A1 of solenoid valve I; port A3 of solenoid valve I connects to hydraulic oil branch EE; hydraulic oil branch EE connects to the first cooling point; port A4 of solenoid valve I also connects to hydraulic oil branch EE via a hydraulic line; hydraulic oil branch AA connects to port B1 of solenoid valve II; hydraulic oil branch CC connects to port B2 of solenoid valve II; port B3 of solenoid valve II connects to hydraulic oil branch FF; hydraulic oil branch FF connects sequentially via hydraulic lines to port B4 of solenoid valve II, port C2 of solenoid valve III, port A2 of solenoid valve I, and the first lubrication point; hydraulic oil branch BB connects to port C1 of solenoid valve III... The C3 port of solenoid valve III is connected to the hydraulic oil branch GG, and the C4 port of solenoid valve III is connected to the hydraulic oil branch GG via a hydraulic pipeline. The hydraulic oil branch GG is connected to the second lubrication point. Temperature sensor I and flow sensor I are installed sequentially on the first cooling point to record the temperature of the first cooling point and the flow rate of the hydraulic oil flowing into it, respectively. Temperature sensor II and flow sensor II are installed sequentially on the first lubrication point to record the temperature of the first lubrication point and the flow rate of the hydraulic oil flowing into it, respectively. Temperature sensor III and flow sensor III are installed sequentially on the second lubrication point to record the temperature of the second lubrication point and the flow rate of the hydraulic oil flowing into it, respectively. The electronic oil pump, solenoid valve I, solenoid valve II, solenoid valve III, temperature sensor I, temperature sensor II, temperature sensor III, flow sensor I, flow sensor II, and flow sensor III are all connected to the electronic control unit.

[0007] A lubrication and cooling control method for an electric vehicle powertrain, characterized in that the control method includes the following specific steps:

[0008] 1) Detect the temperature T1 of the first cooling point and the flow rate q1 of the hydraulic oil flowing into it, the temperature T2 of the first lubrication point and the flow rate q2 of the hydraulic oil flowing into it, and the temperature T3 of the second lubrication point and the flow rate q3 of the hydraulic oil flowing into it; set two target temperature ranges for the first cooling point, the first lubrication point and the second lubrication point, namely T1 and T2 respectively.

[0009] 2) Based on the target temperature and target flow rate settings of the first cooling point, the first lubrication point, and the second lubrication point by the electronic control unit, the three solenoid valves are controlled to be in their corresponding states. The specific working details of each state are as follows:

[0010] A. When the target temperature ranges of T1, T2, and T3 are T1, T2, and T1 respectively, solenoid valves I, II, and III are in the states of no potential, no potential, and no potential respectively. At this time, the hydraulic oil in hydraulic oil branch DD flows sequentially through ports A1 and A3 of solenoid valve I into hydraulic oil branch EE, and the hydraulic oil in hydraulic oil branch EE finally flows into the first cooling point; the hydraulic oil in hydraulic oil branch AA flows sequentially through ports B1 and B3 of solenoid valve II into hydraulic oil branch FF, and the hydraulic oil in hydraulic oil branch FF finally flows into the first lubrication point; the hydraulic oil in hydraulic oil branch BB flows sequentially through ports C1 and C3 of solenoid valve III into hydraulic oil branch GG, and the hydraulic oil in hydraulic oil branch GG finally flows into the second lubrication point.

[0011] B. When the target temperature ranges of T1, T2, and T3 are T1, T2, and T2 respectively, solenoid valves I, II, and III are in the states of no potential, no potential, and potential respectively. At this time, the hydraulic oil in hydraulic oil branch DD flows through ports A1 and A3 of solenoid valve I into hydraulic oil branch EE, and the hydraulic oil in hydraulic oil branch EE finally flows into the first cooling point; the hydraulic oil in hydraulic oil branch AA flows through ports B1 and B3 of solenoid valve II into hydraulic oil branch FF, and the hydraulic oil in hydraulic oil branch FF finally flows into the first lubrication point; the hydraulic oil in hydraulic oil branch BB flows through ports C1 and C3 of solenoid valve III into hydraulic oil branch GG. At the same time, some hydraulic oil flowing out of port B3 of solenoid valve II also flows through ports C2 and C4 of solenoid valve III into hydraulic oil branch GG. At this time, the temperature of the hydraulic oil in hydraulic oil branch GG will rise, and the viscosity of the hydraulic oil here will also change because two kinds of hydraulic oil are mixed—cooled hydraulic oil and uncooled hydraulic oil. The hydraulic oil flowing into the two hydraulic oil branches GG converges and flows into the second lubrication point.

[0012] C. When the target temperature ranges of T1, T2, and T3 are T1, T1, and T1 respectively, solenoid valves I, II, and III are in the states of no potential, potential, and no potential respectively. At this time, the hydraulic oil in hydraulic oil branch DD flows through ports A1 and A3 of solenoid valve I and into hydraulic oil branch EE. The hydraulic oil in hydraulic oil branch EE finally flows into the first cooling point. The hydraulic oil in hydraulic oil branch AA flows through ports B1 and B3 of solenoid valve II and into hydraulic oil branch FF. At the same time, the hydraulic oil in hydraulic oil branch CC flows through ports B2 and B4 of solenoid valve II and into hydraulic oil branch FF. At this time, the temperature of the hydraulic oil in hydraulic oil branch FF will drop, and the viscosity of the hydraulic oil here will also change because two kinds of hydraulic oil are mixed—cooled hydraulic oil and uncooled hydraulic oil. The hydraulic oil flowing into the two hydraulic oil branches FF converges and flows into the first lubrication point; the hydraulic oil in the hydraulic oil branch BB passes through the C1 and C3 ports of the solenoid valve Ⅲ in sequence and flows into the hydraulic oil branch GG. The hydraulic oil in the hydraulic oil branch GG finally flows into the second lubrication point.

[0013] D. When the target temperature ranges of T1, T2, and T3 are T1, T1, and T2 respectively, solenoid valves I, II, and III are in the states of no potential, potential, and potential respectively. At this time, the hydraulic oil in hydraulic oil branch DD flows through ports A1 and A3 of solenoid valve I and into hydraulic oil branch EE. The hydraulic oil in hydraulic oil branch EE finally flows into the first cooling point. The hydraulic oil in hydraulic oil branch AA flows through ports B1 and B3 of solenoid valve II and into hydraulic oil branch FF. At the same time, the hydraulic oil in hydraulic oil branch CC flows through ports B2 and B4 of solenoid valve II and into hydraulic oil branch FF. At this time, the temperature of the hydraulic oil in hydraulic oil branch FF will drop, and the viscosity of the hydraulic oil here will also change because two kinds of hydraulic oil are mixed—cooled hydraulic oil and uncooled hydraulic oil. The hydraulic oil flowing into the two hydraulic oil branches FF converges and flows into the first lubrication point; the hydraulic oil in the hydraulic oil branch BB passes through the C1 and C3 ports of the solenoid valve III in sequence and flows into the hydraulic oil branch GG. The hydraulic oil that previously flowed into the hydraulic oil branch FF from the two converged flows also passes through the C2 and C4 ports of the solenoid valve III in sequence and flows into the hydraulic oil branch GG. The hydraulic oil that flows into the hydraulic oil branch GG from the two converged flows finally into the second lubrication point.

[0014] E. When the target temperature ranges of T1, T2, and T3 are T2, T1, and T1 respectively, solenoid valves I, II, and III are in the states of being at potential, at potential, and not at potential respectively. The hydraulic oil in hydraulic oil branch AA flows into hydraulic oil branch FF through ports B1 and B3 of solenoid valve II in sequence. At the same time, the hydraulic oil in hydraulic oil branch CC flows into hydraulic oil branch FF through ports B2 and B4 of solenoid valve II in sequence. The hydraulic oil from the two branches flows into hydraulic oil branch FF together and flows into the first lubrication port. The hydraulic oil from the two converging streams into hydraulic oil branch FF also flows sequentially through ports A2 and A4 of solenoid valve I into hydraulic oil branch EE; the hydraulic oil from hydraulic oil branch DD flows sequentially through ports A1 and A3 of solenoid valve I into hydraulic oil branch EE, and the hydraulic oil from the two converging streams into hydraulic oil branch EE finally flows into the first cooling port; the hydraulic oil from hydraulic oil branch BB flows sequentially through ports C1 and C3 of solenoid valve III into hydraulic oil branch GG, and the hydraulic oil from hydraulic oil branch GG finally flows into the second lubrication port.

[0015] 3) Based on the information monitored in real time by the electronic control unit, the target required flow rate q for the first cooling point, the first lubrication point, and the second lubrication point is calculated respectively. x1 q x2 q x3 :

[0016]

[0017] In the formula: P t --Efficiency loss, unit Kw; C--Specific heat of lubricating oil, unit kJ / (kg·k); p--Density of lubricating oil, unit kg / m³ 3 ; Δt = TT m --Temperature difference, in °C; q x --Target flow rate, in L / min; η--Lubrication coefficient; T--Actual measured temperature, in °C; T m --Standard temperature, in °C;

[0018] 4) When the actual flow rates q1, q2, and q3 at each point are detected, none of them individually meet their respective target flow rate requirements q x1 q x2 q x3 At that time, the electronic control unit drives the electronic oil pump to accelerate, so that the actual flow rates q1, q2, and q3 at each point meet the target flow rate q. x1 q x2 q x3 If the conditions are met, the electronic oil pump will be controlled to move at a constant speed.

[0019] In the lubrication and cooling control method for the electric vehicle powertrain, the temperature range of T1 is (0, 75]℃, and the temperature range of T2 is (75, 100]℃. When the target temperature at each point is within the range of T1, the standard temperature T used to calculate the target required flow rate at the first cooling point, the first lubrication point, and the second lubrication point is respectively... 1m T 2m T 3m The values ​​are: 100xR1℃, 104xR1℃, 106xR1℃, with a demand factor R1 of 0.5. When the target temperature at each point is within the range T2, the standard temperatures T used to calculate the target flow rate at the first cooling point, first lubrication point, and second lubrication point are respectively... 1m T 2m T 3m The values ​​are: 110 x R2℃, 112 x R2℃, 113 x R2℃, with a demand factor R2 of 0.55.

[0020] In the lubrication and cooling control method of the electric vehicle powertrain, when the actual temperatures of T1, T2, and T3 are within the temperature range of T2, T2, and T3 respectively, η is 1.25; otherwise, η is 1.1.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. The hydraulic circuit of the lubrication and cooling device for the electric vehicle powertrain of the present invention is simple and uses a single type of hydraulic oil. By automatically turning on / off the solenoid valve, hydraulic oils of different temperatures—cooled hydraulic oil and uncooled hydraulic oil—can be mixed in a timely manner to adjust the temperature (viscosity) of the hydraulic oil, thereby meeting the different requirements of the motor, controller, reducer and other components in the electric vehicle powertrain for the temperature of the lubricating and cooling oil.

[0023] 2. The lubrication and cooling control method for the electric vehicle powertrain of the present invention is based on the detection information of each sensor, and detects and compensates for the lubrication and cooling demand flow under different operating conditions in real time, thereby improving the reliability of lubrication and cooling of the electric vehicle powertrain. Attached Figure Description

[0024] Figure 1 This is a hydraulic schematic diagram of the lubrication and cooling device for the electric vehicle powertrain of the present invention;

[0025] Figure 2 This is a flowchart of the lubrication and cooling control method for the electric vehicle powertrain of the present invention.

[0026] Figure 1In the middle section: 1. Oil tank, 2. Coarse filter, 3. Electronic oil pump, 4. Fine filter, 5. Radiator, 6. Solenoid valve I, 7. Temperature sensor I, 8. First cooling point, 9. Flow sensor I, 10. Temperature sensor II, 11. First lubrication point, 12. Flow sensor II, 13. Solenoid valve II, 14. Solenoid valve III, 15. Temperature sensor III, 16. Second lubrication point, 17. Flow sensor III, 18. Electronic control unit; Detailed Implementation

[0027] The invention will now be further described with reference to the accompanying drawings.

[0028] Example 1

[0029] like Figure 1As shown, the lubrication and cooling device of the electric vehicle powertrain of the present invention includes temperature sensor I7, temperature sensor II10, temperature sensor III15, flow sensor I9, flow sensor II12, flow sensor III17, hydraulic device, and electronic control unit 18; the hydraulic device includes oil tank 1, coarse filter 2, electronic oil pump 3, fine filter 4, radiator 5, solenoid valve I6, solenoid valve II13, and solenoid valve III14; oil tank 1 is sequentially connected to coarse filter 2, electronic oil pump 3, and fine filter 4 to form hydraulic oil branch AA, and after being connected to radiator 5, hydraulic oil branches BB, CC, and DD are established respectively. The hydraulic oil temperature at these three locations is lower than that of hydraulic oil branch AA because it has been cooled by the radiator. Hydraulic oil branch DD, after connecting to solenoid valve I6, mainly forms hydraulic oil branch EE; hydraulic oil branch BB, after connecting to solenoid valve III14, mainly forms hydraulic oil branch GG; hydraulic oil branch AA, after connecting to solenoid valve II13, mainly forms hydraulic oil branch FF; hydraulic oil branch DD is connected to port A1 of solenoid valve I6; port A3 of solenoid valve I6 is connected to hydraulic oil branch EE; hydraulic oil branch EE is connected to the first cooling point 8; port A4 of solenoid valve I6 is also connected to... Hydraulic oil branch EE is connected; hydraulic oil branch AA is connected to port B1 of solenoid valve II 13; hydraulic oil branch CC is connected to port B2 of solenoid valve II 13; port B3 of solenoid valve II 13 is connected to hydraulic oil branch FF; hydraulic oil branch FF is connected sequentially to port B4 of solenoid valve II 13, port C2 of solenoid valve III 14, port A2 of solenoid valve I 6, and first lubrication point 11 via hydraulic lines; hydraulic oil branch BB is connected to port C1 and port C3 of solenoid valve III 14. The C4 port of solenoid valve Ⅲ14 is connected to hydraulic oil branch GG via a hydraulic pipeline, and hydraulic oil branch GG is connected to the second lubrication point 16. Temperature sensor Ⅰ7 and flow sensor Ⅰ9 are installed sequentially on the first cooling point 8 to record the temperature of the first cooling point 8 and the flow rate of the hydraulic oil flowing into it, respectively. Temperature sensor Ⅱ10 and flow sensor Ⅱ12 are installed sequentially on the first lubrication point 11 to record the temperature of the first lubrication point 11 and the flow rate of the hydraulic oil flowing into it, respectively. Temperature sensor Ⅲ15 and flow sensor Ⅲ17 are installed sequentially on the second lubrication point 16 to record the temperature of the second lubrication point 16 and the flow rate of the hydraulic oil flowing into it, respectively. Electronic oil pump 3, solenoid valve Ⅰ6, solenoid valve Ⅱ13, solenoid valve Ⅲ14, temperature sensor Ⅰ7, temperature sensor Ⅱ10, temperature sensor Ⅲ15, flow sensor Ⅰ9, flow sensor Ⅱ12, and flow sensor Ⅲ17 are all connected to electronic control unit 18.

[0030] like Figure 2 The specific operation of the lubrication and cooling control method for the electric vehicle powertrain shown is as follows:

[0031] 1) Detect the temperature T1 of the first cooling point 8 and the flow rate q1 of the hydraulic oil flowing into it, the temperature T2 of the first lubrication point 11 and the flow rate q2 of the hydraulic oil flowing into it, and the temperature T3 of the second lubrication point 16 and the flow rate q3 of the hydraulic oil flowing into it; set at least two target temperature ranges for the first cooling point 8, the first lubrication point 11 and the second lubrication point 16, respectively, T1 and T2.

[0032] 2) Based on the target temperature and target flow rate settings of the first cooling point 8, the first lubrication point 11, and the second lubrication point 16 by the electronic control unit 18, the three solenoid valves are controlled to be in their corresponding states. The specific working details of each state are as follows:

[0033] A. When the target temperature ranges T1, T2, and T3 are T1, T2, and T1 respectively, solenoid valves I6, II13, and III14 are in the states of no potential, no potential, and no potential respectively. At this time, the hydraulic oil in hydraulic oil branch DD (which has been cooled) flows sequentially through ports A1 and A3 of solenoid valve I6 into hydraulic oil branch EE. The hydraulic oil in hydraulic oil branch EE finally flows into the first cooling point 8 to cool the components at the first cooling point 8, ensuring that its actual temperature is within the T1 range. The hydraulic oil in hydraulic oil branch AA (which has not been cooled) flows into the first cooling point 8 into the first cooling point 8. The hydraulic oil from the first lubrication point 11 flows through ports B1 and B3 of solenoid valve II13 and into hydraulic oil branch FF. The hydraulic oil from hydraulic oil branch FF flows into the first lubrication point 11 to cool and lubricate the components of the first lubrication point 11, keeping its actual temperature within the range of T2. The hydraulic oil from hydraulic oil branch BB (which has been cooled) flows through ports C1 and C3 of solenoid valve III14 and into hydraulic oil branch GG. The hydraulic oil from hydraulic oil branch GG flows into the second lubrication point 16 to cool and lubricate the components of the second lubrication point 16, keeping its actual temperature within the range of T1.

[0034] B. When the target temperature ranges T1, T2, and T3 are T1, T2, and T2 respectively, solenoid valves I6, II13, and III14 are in the states of no potential, no potential, and potential respectively. At this time, the hydraulic oil in hydraulic oil branch DD (which has been cooled) flows sequentially through ports A1 and A3 of solenoid valve I6 into hydraulic oil branch EE. The hydraulic oil in hydraulic oil branch EE finally flows into the first cooling point 8 to cool the components at the first cooling point 8, so that its actual temperature is within the T1 range. The hydraulic oil in hydraulic oil branch AA (which has not been cooled) flows sequentially through ports B1 and B3 of solenoid valve II13 into hydraulic oil branch FF. The hydraulic oil in hydraulic oil branch FF finally flows into The first lubrication point 11 is used to cool and lubricate the components at the first lubrication point 11, keeping its actual temperature within the T2 range. The hydraulic oil (already cooled) from hydraulic oil branch BB flows sequentially through ports C1 and C3 of solenoid valve III 14 into hydraulic oil branch GG. Simultaneously, a portion of the hydraulic oil (not cooled) from hydraulic oil branch AA in hydraulic oil branch FF also flows sequentially through ports C2 and C4 of solenoid valve III 14 into hydraulic oil branch GG. At this time, the temperature of the hydraulic oil in hydraulic oil branch GG will relatively rise, and the viscosity of the hydraulic oil here will also change accordingly, because the hydraulic oil (already cooled) from hydraulic oil branch BB is mixed with the hydraulic oil (not cooled) from hydraulic oil branch AA. The hydraulic oil flowing into hydraulic oil branch GG from both branches converges and flows into the second lubrication point 16, used to cool and lubricate the components at the second lubrication point 16, keeping its actual temperature within the T2 range.

[0035] C. When the target temperature ranges of T1, T2, and T3 are T1, T1, and T1 respectively, solenoid valves I6, II13, and III14 are in the states of no potential, potential, and no potential respectively. At this time, the hydraulic oil (already cooled) in hydraulic oil branch DD flows sequentially through ports A1 and A3 of solenoid valve I6 into hydraulic oil branch EE. The hydraulic oil in hydraulic oil branch EE finally flows into the first cooling point 8 to cool the components at the first cooling point 8, ensuring that its actual temperature is within the T1 range. Hydraulic oil from line AA (uncooled) flows sequentially through ports B1 and B3 of solenoid valve II13 into hydraulic oil branch FF. Simultaneously, hydraulic oil from hydraulic oil branch CC (cooled) flows sequentially through ports B2 and B4 of solenoid valve II13 into hydraulic oil branch FF. At this point, the temperature of the hydraulic oil in hydraulic oil branch FF will relatively decrease, and the viscosity of the hydraulic oil at this point will also change, because the hydraulic oil from hydraulic oil branch AA (uncooled) is mixed with the hydraulic oil from hydraulic oil branch CC (cooled). The hydraulic oil flowing into hydraulic oil branch FF from both lines converges and flows into the first lubrication point 11 to cool and lubricate the components at the first lubrication point 11, keeping its actual temperature within the T1 range. Hydraulic oil from hydraulic oil branch BB (cooled) flows sequentially through ports C1 and C3 of solenoid valve III14 into hydraulic oil branch GG. The hydraulic oil from hydraulic oil branch GG finally flows into the second lubrication point 16 to cool and lubricate the components at the second lubrication point 16, keeping its actual temperature within the T1 range.

[0036] D. When the target temperature ranges of T1, T2, and T3 are T1, T1, and T2 respectively, solenoid valves I6, II13, and III14 are in the states of no potential, potential, and potential respectively. At this time, the hydraulic oil (already cooled) in hydraulic oil branch DD flows sequentially through ports A1 and A3 of solenoid valve I6 into hydraulic oil branch EE. The hydraulic oil in hydraulic oil branch EE finally flows into the first cooling point 8 to cool the components at the first cooling point 8, ensuring that its actual temperature is within the T1 range. Hydraulic oil from AA (uncooled) flows sequentially through ports B1 and B3 of solenoid valve II13 into hydraulic oil branch FF. Simultaneously, hydraulic oil from hydraulic oil branch CC (cooled) flows sequentially through ports B2 and B4 of solenoid valve II13 into hydraulic oil branch FF. At this time, the temperature of the hydraulic oil in hydraulic oil branch FF will decrease relatively, and the viscosity of the hydraulic oil here will also change accordingly, because the hydraulic oil from hydraulic oil branch AA (uncooled) is mixed with the hydraulic oil from hydraulic oil branch CC (cooled). The hydraulic oil flowing into hydraulic oil branch FF from both branches converges and flows into the first lubrication point 11 to cool and lubricate the components, keeping their actual temperature within the T1 range. The hydraulic oil (already cooled) from hydraulic oil branch BB flows into hydraulic oil branch GG through ports C1 and C3 of solenoid valve III 14. A portion of the hydraulic oil that previously flowed into hydraulic oil branch FF from both branches AA and CC also flows into hydraulic oil branch GG through ports C2 and C4 of solenoid valve III. At this point, the temperature of the hydraulic oil in hydraulic oil branch GG will rise relatively, and its viscosity will also change because it is mixed with some uncooled hydraulic oil from hydraulic oil branch AA, in addition to the cooled hydraulic oil from hydraulic oil branch BB. The hydraulic oil flowing into hydraulic oil branch GG from both branches finally flows into the second lubrication point 16 to cool and lubricate the components, keeping their actual temperature within the T2 range.

[0037] E. When the target temperature ranges of T1, T2, and T3 are T2, T1, and T1 respectively, solenoid valves I6, II13, and III14 are in the states of being at potential, at potential, and not at potential, respectively. The hydraulic oil in hydraulic oil branch AA (which has not been cooled) flows into hydraulic oil branch FF through ports B1 and B3 of solenoid valve II13 in sequence. At the same time, the hydraulic oil in hydraulic oil branch CC (which has been cooled) flows into hydraulic oil branch FF through ports B2 and B4 of solenoid valve II13 in sequence. At this time, the temperature of the hydraulic oil in hydraulic oil branch FF will decrease relatively, and the viscosity of the hydraulic oil here will also change accordingly, because the hydraulic oil in hydraulic oil branch AA (which has not been cooled) is mixed with the hydraulic oil from hydraulic oil branch CC (which has been cooled). The hydraulic oil from the two converging hydraulic oil branches FF flows into the first lubrication port 11 to cool and lubricate the components at the first lubrication point 11, keeping its actual temperature within the T1 range. Previously, hydraulic oil from both branches AA and CC flowed into hydraulic oil branch FF, passing sequentially through ports A2 and A4 of solenoid valve I6 before flowing into hydraulic oil branch EE. Simultaneously, hydraulic oil from branch DD (already cooled) passes sequentially through ports A1 and A3 of solenoid valve I6 before flowing into hydraulic oil branch EE. The temperature of the hydraulic oil in hydraulic oil branch EE will rise relatively, and the viscosity of the hydraulic oil at this point will also change accordingly. Hydraulic oil (already cooled) from hydraulic oil branch DD is mixed with uncooled hydraulic oil from a portion of hydraulic oil branch AA. The two streams converge and flow into hydraulic oil branch EE, which finally flows into the first cooling port 8 to cool the components at the first cooling point 8, keeping their actual temperature within the T2 range. Hydraulic oil (already cooled) from hydraulic oil branch BB passes through ports C1 and C3 of solenoid valve Ⅲ14 and flows into hydraulic oil branch GG. The hydraulic oil from hydraulic oil branch GG finally flows into the second lubrication port 16 to cool and lubricate the components at the second lubrication point 16, keeping their actual temperature within the T1 range.

[0038] 3) Based on the information monitored in real time by the electronic control unit 18, the target required flow rate q for the first cooling point 8, the first lubrication point 11, and the second lubrication point 16 is calculated respectively. x1 q x2 q x3 :

[0039]

[0040] In the formula: P t --Efficiency loss, unit Kw; C--Specific heat of lubricating oil, unit kJ / (kg·k); p--Density of lubricating oil, unit kg / m³ 3 ; Δt = TT m --Temperature difference, in °C; q x--Target flow rate, in L / min; η--Lubrication coefficient; T--Actual measured temperature, in °C; T m --Standard temperature, in °C;

[0041] 4) When the actual flow rates q1, q2, and q3 at each point are detected, none of them individually meet their respective target flow rate requirements q x1 q x2 q x3 At that time, the electronic control unit drives the electronic oil pump to accelerate, so that the actual flow rates q1, q2, and q3 at each point meet the target flow rate q. x1 q x2 q x3 If the conditions are met, the electronic oil pump will be controlled to move at a constant speed.

[0042] In the lubrication and cooling control method for the electric vehicle powertrain, the temperature range of T1 is (0, 75]℃, and the temperature range of T2 is (75, 100]℃. When the target temperature at each point is within the range of T1, the standard temperature T used to calculate the target required flow rate is respectively at the first cooling point 8, the first lubrication point 11, and the second lubrication point 16. 1m T 2m T 3m The values ​​are: 100xR1℃, 104xR1℃, 106xR1℃, with a demand factor R1 of 0.5. When the target temperature at each point is within the range T2, the standard temperatures T used to calculate the target flow rate are: first cooling point 8, first lubrication point 11, and second lubrication point 16. 1m T 2m T 3m The values ​​are: 110 x R2℃, 112 x R2℃, 113 x R2℃, with a demand factor R2 of 0.55.

[0043] In the lubrication and cooling control method of the electric vehicle powertrain, when the actual temperatures of T1, T2, and T3 are within the temperature range of T2, T2, and T3 respectively, η is 1.25; otherwise, η is 1.1.

[0044] Example 2

[0045] Assuming the target temperature at each point is within the range T1, the standard temperatures T used to calculate the target required flow rate are as follows: first cooling point 8, first lubrication point 11, and second lubrication point 16. 1m T 2m T 3m The required temperatures are: 100 x R1 = 100 x 0.5 = 50℃, 104 x R1 = 104 x 0.5 = 52℃, 106 x R1 = 106 x 0.5 = 53℃, and the demand factor R1 is 0.5. The control method for the lubrication and cooling device is as follows:

[0046] 1) Assume that the actual temperature T1 of the first cooling point 8 and the hydraulic oil flow rate q1 flowing into it are 70℃ and 8.52L / min, respectively; the actual temperature T2 of the first lubrication point 11 and the hydraulic oil flow rate q2 flowing into it are 70℃ and 9.43L / min, respectively; and the actual temperature T3 of the second lubrication point 16 and the hydraulic oil flow rate q3 flowing into it are 72℃ and 9.01L / min, respectively.

[0047] 2) Assuming the target temperature at each point is within the range of T1, T1, T1, the standard temperature T used to calculate the target required flow rate at the first cooling point 8, the first lubrication point 11, and the second lubrication point 16 is... 1m T 2m T 3m The temperatures are 50℃, 52℃, and 53℃, respectively.

[0048] 3) Solenoid valve I6, solenoid valve II13, and solenoid valve III14 are in the states of no potential, potential, and no potential, respectively. The hydraulic oil flow path on each hydraulic branch is as described above.

[0049] 4) Based on the information monitored in real time by the electronic control unit 18, the target required flow rate q for the first cooling point 8, the first lubrication point 11, and the second lubrication point 16 is calculated respectively. x1 q x2 q x3 for:

[0050]

[0051]

[0052]

[0053] Where: P t --Efficiency loss, 5.1 kW; C--Specific heat of lubricating oil, 2.1 kJ / (kg·K); p--Density of lubricating oil, 0.97 x 10⁻⁶ 3 kg / m 3 ; Δt1=T1-T 1m --Temperature difference, 20℃; Δt2=T2-T 2m --Temperature difference, 18℃, Δt3=T3-T 3m --Temperature difference, 19℃; q x --Target demand flow rate, L / min; η--1.1; Demand coefficient R1--0.5;

[0054] 4) The actual flow rates at each point were detected to be 8.52 L / min, 9.43 L / min, and 9.01 L / min, respectively. The target flow rates of 8.26 L / min, 9.18 L / min, and 8.7 L / min were met, and the electronic oil pump 3 was controlled to continue moving at a constant speed.

[0055] In this way, the lubrication and cooling control method of the electric vehicle powertrain collects the detection information from various sensors in real time. Based on the designed control algorithm, it detects and compensates for the actual flow rate at each lubrication and cooling point in real time, meeting the target flow rate requirements of the motor, controller, reducer, etc. in the electric vehicle powertrain, thus improving the reliability of lubrication and cooling of the electric vehicle powertrain. At the same time, the lubrication and cooling device of the electric vehicle powertrain is simple, requiring only a single type of hydraulic oil. By controlling the energization / de-energization of the corresponding solenoid valve, hydraulic oil of different temperatures—cooled hydraulic oil and uncooled hydraulic oil—is mixed in a timely manner to adjust the temperature (viscosity) of the hydraulic oil, thereby simultaneously meeting the different requirements of the motor, controller, reducer, etc. in the electric vehicle powertrain for lubrication and cooling oil temperature.

Claims

1. A lubrication and cooling device for an electric vehicle powertrain, comprising temperature sensor I, temperature sensor II, temperature sensor III, flow sensor I, flow sensor II, flow sensor III, a hydraulic device, and an electronic control unit; characterized in that: The hydraulic system includes an oil tank, a coarse filter, an electronic oil pump, a fine filter, a radiator, solenoid valve I, solenoid valve II, and solenoid valve III. The oil tank is sequentially connected to the coarse filter, electronic oil pump, and fine filter to form hydraulic oil branch AA. Continuing to connect to the radiator, hydraulic oil branches BB, CC, and DD are established. Hydraulic oil branch DD connects to solenoid valve I to form hydraulic oil branch EE. Hydraulic oil branch BB connects to solenoid valve III to form hydraulic oil branch GG. Hydraulic oil branch AA connects to solenoid valve II to form hydraulic oil branch FF. Hydraulic oil branch DD is connected to port A1 of solenoid valve I, and port A3 of solenoid valve I is connected to hydraulic oil branch EE. Hydraulic oil branch E... E is connected to the first cooling point. The A4 port of solenoid valve I is also connected to the hydraulic oil branch EE via a hydraulic pipeline. The hydraulic oil branch AA is connected to the B1 port of solenoid valve II. The hydraulic oil branch CC is connected to the B2 port of solenoid valve II. The B3 port of solenoid valve II is connected to the hydraulic oil branch FF. The hydraulic oil branch FF is also connected to the B4 port of solenoid valve II, the C2 port of solenoid valve III, the A2 port of solenoid valve I, and the first lubrication point via a hydraulic pipeline. The hydraulic oil branch BB is connected to the C1 port of solenoid valve III. The C3 port of solenoid valve III is connected to the hydraulic oil branch GG. The C4 port of solenoid valve III is connected to the hydraulic oil branch GG via a hydraulic pipeline. The hydraulic oil branch GG is connected to the second lubrication point. Temperature sensor I and flow sensor I are installed sequentially on the first cooling point to record the temperature of the first cooling point and the flow rate of the hydraulic oil flowing into it, respectively. Temperature sensor II and flow sensor II are installed sequentially on the first lubrication point to record the temperature of the first lubrication point and the flow rate of the hydraulic oil flowing into it, respectively. Temperature sensor III and flow sensor III are installed sequentially on the second lubrication point to record the temperature of the second lubrication point and the flow rate of the hydraulic oil flowing into it, respectively. The electronic oil pump, solenoid valve I, solenoid valve II, solenoid valve III, temperature sensor I, temperature sensor II, temperature sensor III, flow sensor I, flow sensor II, and flow sensor III are all connected to the electronic control unit.

2. A control method applied to the lubrication and cooling device according to claim 1, characterized in that, The control method includes the following specific steps: 1) Detect the temperature of the first cooling point respectively. T 1 and its inflow hydraulic oil flow rate q 1. Temperature of the first lubrication point T 2 and the flow rate of the hydraulic oil flowing into it. q 2. Temperature of the second lubrication point T 3. The flow rate of the hydraulic oil flowing into it q 3; The first cooling point, the first lubrication point, and the second lubrication point are each set with two target temperature ranges, T1 and T2 respectively; 2) Based on the target temperature and target flow rate settings of the first cooling point, the first lubrication point, and the second lubrication point by the electronic control unit, the three solenoid valves are controlled to be in their corresponding states. The specific working details of each state are as follows: A.When T 1, T 2, T When the target temperature ranges are T1, T2, and T1 respectively, solenoid valves I, II, and III are in the states of no potential, no potential, and no potential respectively. At this time, the hydraulic oil in hydraulic oil branch DD flows through ports A1 and A3 of solenoid valve I and into hydraulic oil branch EE. The hydraulic oil in hydraulic oil branch EE finally flows into the first cooling point. The hydraulic oil in hydraulic oil branch AA flows through ports B1 and B3 of solenoid valve II and into hydraulic oil branch FF. The hydraulic oil in hydraulic oil branch FF finally flows into the first lubrication point. The hydraulic oil in hydraulic oil branch BB flows through ports C1 and C3 of solenoid valve III and into hydraulic oil branch GG. The hydraulic oil in hydraulic oil branch GG finally flows into the second lubrication point. B. When T 1, T 2, T When the target temperature ranges of 3 are T1, T2, and T2 respectively, solenoid valves I, II, and III are in the states of no potential, no potential, and potential respectively. At this time, the hydraulic oil in hydraulic oil branch DD flows through ports A1 and A3 of solenoid valve I and into hydraulic oil branch EE. The hydraulic oil in hydraulic oil branch EE finally flows into the first cooling point. The hydraulic oil in hydraulic oil branch AA flows through ports B1 and B3 of solenoid valve II and into hydraulic oil branch FF. The hydraulic oil in hydraulic oil branch FF finally flows into the first lubrication point. The hydraulic oil in hydraulic oil branch BB flows through ports C1 and C3 of solenoid valve III and into hydraulic oil branch GG. At the same time, part of the hydraulic oil flowing out of port B3 of solenoid valve II also flows through ports C2 and C4 of solenoid valve III into hydraulic oil branch GG. The hydraulic oil flowing into hydraulic oil branch GG from both branches converges and flows into the second lubrication point. C. When T 1, T 2, T When the target temperature ranges of 3 are T1, T1, and T1 respectively, solenoid valves I, II, and III are in the states of no potential, potential, and no potential respectively. At this time, the hydraulic oil in hydraulic oil branch DD flows through ports A1 and A3 of solenoid valve I and into hydraulic oil branch EE. The hydraulic oil in hydraulic oil branch EE finally flows into the first cooling point. The hydraulic oil in hydraulic oil branch AA flows through ports B1 and B3 of solenoid valve II and into hydraulic oil branch FF. At the same time, the hydraulic oil in hydraulic oil branch CC flows through ports B2 and B4 of solenoid valve II and into hydraulic oil branch FF. The hydraulic oil flowing into hydraulic oil branch FF from both branches converges and flows into the first lubrication point. The hydraulic oil in hydraulic oil branch BB flows through ports C1 and C3 of solenoid valve III and into hydraulic oil branch GG. The hydraulic oil in hydraulic oil branch GG finally flows into the second lubrication point. D. When T 1, T 2, T When the target temperature ranges are T1, T2, and T3 respectively, solenoid valves I, II, and III are in the states of no potential, potential, and potential respectively. At this time, the hydraulic oil in hydraulic oil branch DD flows sequentially through ports A1 and A3 of solenoid valve I into hydraulic oil branch EE, and the hydraulic oil in hydraulic oil branch EE finally flows into the first cooling point; the hydraulic oil in hydraulic oil branch AA flows sequentially through ports B1 and B3 of solenoid valve II into hydraulic oil branch FF, and at the same time, the hydraulic oil in hydraulic oil branch CC flows sequentially through ports B1 and B3 of solenoid valve II into hydraulic oil branch FF.

2. At port B4, hydraulic oil flows into hydraulic oil branch FF. The hydraulic oil flowing into hydraulic oil branch FF from both branches converges and flows into the first lubrication point. The hydraulic oil from hydraulic oil branch BB passes through ports C1 and C3 of solenoid valve III in sequence and flows into hydraulic oil branch GG. The hydraulic oil that previously started from hydraulic oil branch AA and pressure oil branch CC and flowed into hydraulic oil branch FF from both branches also passes through ports C2 and C4 of solenoid valve III in sequence and flows into hydraulic oil branch GG. The hydraulic oil that flows into hydraulic oil branch GG from both branches finally flows into the second lubrication point. E.When T 1, T 2, T When the target temperature ranges are T2, T1, and T1 respectively, solenoid valves I, II, and III are in the states of being at potential, at potential, and at no potential, respectively. Hydraulic oil from hydraulic oil branch AA flows sequentially through ports B1 and B3 of solenoid valve II into hydraulic oil branch FF. Simultaneously, hydraulic oil from hydraulic oil branch CC flows sequentially through ports B2 and B4 of solenoid valve II into hydraulic oil branch FF. The hydraulic oil from both branches converges and flows into the first lubrication port. Previously, hydraulic oil from hydraulic oil branches AA and CC flowed simultaneously into the first lubrication port. The hydraulic oil from branch CC flows into hydraulic oil branch FF and passes through ports A2 and A4 of solenoid valve I before flowing into hydraulic oil branch EE. The hydraulic oil from branch DD flows through ports A1 and A3 of solenoid valve I before flowing into hydraulic oil branch EE. The hydraulic oil from both branches flows into hydraulic oil branch EE and finally into the first cooling port. The hydraulic oil from branch BB flows through ports C1 and C3 of solenoid valve III before flowing into hydraulic oil branch GG. The hydraulic oil from branch GG finally flows into the second lubrication port. 3) Based on the information monitored in real time by the electronic control unit, the target flow rate requirements for the first cooling point, the first lubrication point, and the second lubrication point are calculated respectively. , , : ； In the formula: --Efficiency loss, unit Kw; C--Specific heat of lubricating oil, unit kJ / (kg·k); p --Lubricating oil density, unit ; t = T - T m --Temperature difference, in °C; --Target flow rate, in L / min; --Lubrication coefficient; T —Actual measured temperature, in °C; T m --Standard temperature, in °C; 4) When the actual flow rate at each point is detected q 1, q 2, q 3. Individual or none of them meet their respective target traffic requirements , , At that time, the electronic control unit drives the electronic oil pump to accelerate, thereby increasing the actual flow rate at each point. q 1, q 2, q 3. Satisfy the target flow , , If the conditions are met, the electronic oil pump will be controlled to move at a constant speed.

3. The control method as described in claim 2, characterized in that: The temperature range of T1 is (0, 75]℃, and the temperature range of T2 is (75, 100]℃. When the target temperature at each point is within the T1 range, the standard temperatures T1m, T2m, and T3m used to calculate the target flow rate at the first cooling point, the first lubrication point, and the second lubrication point are respectively: 100xR1℃, 104xR1℃, and 106xR1℃, with a demand coefficient R1 of 0.

5. When the target temperature at each point is within the T2 range, the standard temperatures T1m, T2m, and T3m used to calculate the target flow rate at the first cooling point, the first lubrication point, and the second lubrication point are respectively: 110xR2℃, 112xR2℃, and 113xR2℃, with a demand coefficient R2 of 0.

55.

4. The control method as described in claim 2, characterized in that: when T 1, T 2, T When the actual temperature of 3 is within the temperature ranges of T2, T2, and T2 respectively, It is 1.25; conversely, The value is 1.1.

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