Control method of oil cooling type driving motor oil pump of electric automobile

Abstract

The invention discloses a method for controlling an oil pump of an oil-cooled driving motor of an electric vehicle, which comprises the following steps of: acquiring state parameters and real-time temperature data of a current driving motor in real time; and corresponding oil pump control parameters are matched based on the state parameters of the driving motor and / or the real-time temperature data of the driving motor, and driving control is conducted on the oil pump based on the oil pump control parameters. The method has the advantages that oil pump control is matched with actual requirements, unnecessary energy consumption is reduced, loss of the oil pump is reduced, and the service life is prolonged. The oil pump can be accurately driven to work according to the current working condition of the driving motor, the cooling effect is further improved, and meanwhile the influence of long-time high-load work of the oil pump on the service life of the oil pump and energy consumption generated by operation of the oil pump are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile motor cooling control, in particular to a control method of an oil-cooled driving motor oil pump of an electric vehicle. BACKGROUND

[0002] The commonly used technical solutions of the heat dissipation mode of the driving motor system of an electric vehicle include air cooling, water cooling and oil cooling. In the early stage, electric vehicles were mainly small and micro vehicles, and the driving motors thereof generally had small power and were mostly directly air-cooled for heat dissipation, which was low in cost and simple in technology. With the gradual expansion of electric vehicle models and the improvement of the energy consumption requirement of electric vehicles, the power of driving motors gradually increases, and the efficiency requirement is higher, so the water cooling scheme is widely applied.

[0003] Most of the current driving motors with a peak power below 150 kW adopt a water-cooled heat dissipation system, which is arranged on the heat dissipation water jacket of the driving motor shell and removes the heat generated in the working process of the driving motor through a water pump. The technical solution is mature, but the heat dissipation effect cannot reach the best because the motor heating components cannot be directly cooled, and the shell body processing technology is complex, the volume is large and the cost is high due to the increase of the water jacket on the motor shell.

[0004] The oil cooling type is the best in heat dissipation performance because it directly cools the motor heating components, and is gradually applied in high-power driving motors and high-end vehicles. However, the current control method of the oil-cooled motor oil pump is mainly constant output or only associated with the motor temperature, and the matching degree of the control and driving of the oil pump and the actual demand of the cooling system of the driving motor is low, which cannot efficiently utilize the oil cooling system and affects the service life and energy consumption of the oil pump. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a control method of an oil-cooled driving motor oil pump of an electric vehicle, which controls the oil pump to work in different modes according to different driving motor temperatures or different N-T regions of the driving motor, controls the oil pump to output different flow rates in different working modes, so as to match the oil pump control with the actual demand, reduce unnecessary energy consumption, reduce the loss of the oil pump and improve the service life.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a control method of an oil-cooled driving motor oil pump of an electric vehicle, which comprises collecting real-time state parameters and real-time temperature data of the current driving motor, matching corresponding oil pump control parameters based on the state parameters of the driving motor and / or the real-time temperature data of the driving motor, and driving and controlling the oil pump based on the oil pump control parameters.

[0007] The plurality of oil pump working modes matching the oil pump control parameters and / or temperature data are preset, the oil pump working mode corresponding to the current driving motor is determined based on the current driving motor state parameter and / or temperature data, and the oil pump is controlled based on the determined oil pump working mode.

[0008] The collected current driving motor state parameter includes a driving motor speed signal and a torque signal.

[0009] The plurality of oil pump working modes respectively match different oil pump output flow rates; after entering the oil pump working mode, the oil pump is controlled by using the corresponding oil pump output flow rate.

[0010] The oil pump working mode of the current oil pump is determined based on the collected driving motor speed signal, torque signal and external characteristic N-T curve of the driving motor, or the oil pump working mode of the current oil pump is determined based on the temperature.

[0011] The oil pump working mode includes a first mode, a second mode, a third mode and a fourth mode; when being in the first mode, the second mode, the third mode and the fourth mode, the output flow rate of the oil pump is controlled to be Q1, Q2, Q3 and Q4 respectively; wherein the output flow rate is set as Q1<Q2<Q3<Q4.

[0012] When the driving motor temperature t is less than a preset temperature t a , or the driving motor works in an N-T curve A region, it is determined to enter the first mode state of the oil pump working mode, and the oil pump is controlled according to the output flow rate Q1 in the first mode; wherein the N-T curve A region refers to a region surrounded by the rated N-T curve and the N coordinate between the speed 0 and the rated speed Ni.

[0013] When the driving motor temperature t is t a ≤t<t b , or the driving motor works in an N-T curve B region, it is determined to enter the second mode state of the oil pump working mode, and the oil pump is controlled according to the output flow rate Q2 in the second mode; wherein the N-T curve B region refers to a part of the region surrounded by the rated N-T curve and the N coordinate, except the A region.

[0014] When the driving motor temperature t is t b ≤t<t c , or the driving motor works in an N-T curve C region, it is determined to enter the third mode state of the oil pump working mode, and the oil pump is controlled according to the output flow rate Q3 in the third mode; wherein the N-T curve C region refers to a region between the peak N-T curve and the rated N-T curve.

[0015] When the driving motor temperature t is t≥tc Or drive motor is in the locked rotor mode, then determine into the fourth mode state of the oil pump working mode, in the fourth mode, the oil pump is controlled according to the output flow Q4.

[0016] The advantage of the present application is that the oil pump control matches the actual demand, reduces unnecessary energy consumption, reduces the loss of the oil pump, and improves the service life. The oil pump can be accurately driven according to the current working condition of the driving motor, further improving the cooling effect, while reducing the influence of long-time high-load work of the oil pump on the service life of the oil pump itself and the energy consumption generated by the operation of the oil pump. BRIEF DESCRIPTION OF DRAWINGS

[0017] The content expressed by each figure of the present application specification and the marks in the figure are briefly described as follows:

[0018] Figure 1 The structure block diagram of the oil-cooled driving motor oil pump system for electric vehicles;

[0019] Figure 2 The working external characteristic curve (N-T curve) diagram of the oil-cooled driving motor for electric vehicles;

[0020] Figure 3 The control method flow chart of the oil-cooled driving motor oil pump for electric vehicles;

[0021] Figure 4 The working mode and driving motor temperature curve diagram of the oil-cooled driving motor oil pump for electric vehicles;

[0022] Figure 5 The working mode judgment flow chart of the oil-cooled driving motor oil pump for electric vehicles. DETAILED DESCRIPTION

[0023] The specific embodiments of the present application are further described in detail below by comparing the figures and describing the optimal embodiments.

[0024] In order to improve the efficiency and power density of the electric vehicle drive motor system, reduce the cost, improve the heat dissipation performance of the drive motor system is an effective solution. The commonly used drive motor system heat dissipation mode has air cooling, water cooling, oil cooling, among which the oil cooling type is the best because it directly cools the motor heating components. The present application provides a control method for an oil-cooled drive motor oil pump system of an electric vehicle. The method controls the oil pump to work in different modes according to the different temperatures of the drive motor or the different N-T regions of the drive motor. The oil pump is controlled to output different flow rates in different working modes, so that the motor can be cooled by the matched oil pump flow rate in different states. The actual output flow rate of the cooling oil pump matches the actual cooling demand of the motor, thereby avoiding the problem that the flow rate of the cooling water pump is less than the actual demand, which leads to ineffective cooling, and the flow rate is greater than the actual demand, which leads to waste of flow rate, resulting in that the oil pump works in an overload or unnecessary load state, thereby affecting the service life of the oil pump and increasing the energy consumption. Therefore, the present application controls the oil pump by matching the demand.

[0025] The control method for the oil-cooled drive motor oil pump of the electric vehicle provided in the embodiment comprises collecting the state parameters and real-time temperature data of the current drive motor, matching the corresponding oil pump control parameters based on the state parameters of the drive motor and / or the real-time temperature data of the drive motor, and driving and controlling the oil pump based on the oil pump control parameters.

[0026] The oil pump control parameter is a basic parameter for controlling the oil pump. In the embodiment, the output flow rate of the oil pump is used as the control parameter. Different flow rates represent different flow rates, which realize different cooling capacities. The greater the flow rate, the better the cooling. Therefore, by matching the corresponding control parameters based on the operating state or temperature of the motor, the actual cooling demand and the oil pump control can be matched, thereby achieving effective oil pump control.

[0027] In a preferred scheme, a plurality of oil pump working modes matched with the oil pump control parameters and / or temperature data are set in advance, the oil pump working mode corresponding to the current drive motor is determined based on the state parameters and / or temperature data of the drive motor, and the oil pump is controlled based on the determined oil pump working mode. The plurality of oil pump working modes respectively match different oil pump output flow rates; the oil pump is controlled by the corresponding oil pump output flow rate after entering the oil pump working mode.

[0028] In the embodiment, the oil pump working mode provides four working modes, i.e. a first mode, a second mode, a third mode and a fourth mode. The output flow rates of the oil pump are controlled to be Q1, Q2, Q3 and Q4 respectively in the first mode, the second mode, the third mode and the fourth mode. The output flow rates are set as Q1<Q2<Q3<Q4.

[0029] The first mode is an idle mode, in which the heat dissipation requirement in the idle state is met; the second mode is a rated mode, in which the heat dissipation requirement of the motor in the rated mode is met; the third mode is a peak mode, in which the heat dissipation requirement of the motor in the peak state is met; and the fourth mode is a limit mode, in which the heat dissipation requirement of the motor in the locked-rotor state is met.

[0030] For different oil pump working modes, the temperature or the collected state parameters of the driving motor are used to determine which mode the driving motor belongs to, wherein the collected state parameters of the current driving motor include a speed signal and a torque signal of the driving motor. The oil pump working mode of the current oil pump is determined according to the collected speed signal and torque signal of the driving motor and the external characteristic N-T curve of the driving motor, or the oil pump working mode of the current oil pump is determined based on the temperature.

[0031] When the driving motor temperature t is less than a preset temperature t a , or the driving motor works in the N-T curve A region, it is determined that the first mode state of the oil pump working mode is entered, and the oil pump is controlled according to the output flow Q1 in the first mode; wherein the N-T curve A region refers to the region surrounded by the rated N-T curve and the N coordinate between the speed 0 and the rated speed Ni.

[0032] When the driving motor temperature t is in the range of t a ≤t<t b , or the driving motor works in the B region in the N-T curve, it is determined that the second mode state of the oil pump working mode is entered, and the oil pump is controlled according to the output flow Q2 in the second mode; wherein the B region in the N-T curve refers to the part of the region surrounded by the rated N-T curve and the N coordinate, except the A region.

[0033] When the driving motor temperature t is in the range of t b ≤t<t c , or the driving motor works in the C region in the N-T curve, it is determined that the third mode state of the oil pump working mode is entered, and the oil pump is controlled according to the output flow Q3 in the third mode; wherein the C region in the N-T curve refers to the region between the peak N-T curve and the rated N-T curve.

[0034] When the driving motor temperature t is in the range of t≥t c , or the driving motor works in the locked-rotor mode, it is determined that the fourth mode state of the oil pump working mode is entered, and the oil pump is controlled according to the output flow Q4 in the fourth mode.

[0035] Through the above scheme, the current driving motor matched oil pump working mode can be judged through the current temperature or driving motor parameter collected, and then the working of the oil pump is controlled through the oil pump flow corresponding to the matched mode to realize that the oil pump heat dissipation capacity matches the driving motor heat dissipation demand.

[0036] As shown in Figure 1 An electric vehicle oil-cooled driving motor oil pump system mainly comprises a signal detection system, an oil pump control module and an oil pump, wherein the signal detection system comprises a vehicle key, a driving motor temperature detection module, a driving motor speed detection module and a driving motor torque detection module. The signal detection system is mainly responsible for detecting and feeding back the key signal, the temperature signal, the speed signal and the torque signal; the oil pump control module is responsible for receiving the related signals and judging the control mode; and the oil pump is responsible for executing the corresponding working mode.

[0037] Based on the control system, the application provides an electric vehicle oil-cooled driving motor oil pump control method, which comprises the following steps: according to different driving motor temperatures or different N-T regions of the driving motor, controlling the oil pump to work in different modes, including an idle speed mode, a rated mode, a peak value mode and a limit mode, and controlling the oil pump to output in different flows in different working modes.

[0038] As shown in Figure 1 The electric vehicle oil-cooled driving motor oil pump system mainly comprises a signal detection system, an oil pump control module and an oil pump, wherein the signal detection system comprises a vehicle key, a driving motor temperature detection module, a driving motor speed detection module and a driving motor torque detection module. The signal detection system is mainly responsible for detecting and feeding back the key signal, the temperature signal, the speed signal and the torque signal; the oil pump control module is responsible for receiving the related signals and judging the control mode; and the oil pump is responsible for executing the corresponding working mode.

[0039] As shown in Figure 2 The electric vehicle oil-cooled driving motor working external characteristic curve (N-T curve) graph comprises four quadrants, i.e., a first quadrant, a second quadrant, a third quadrant and a fourth quadrant. The first quadrant corresponds to a vehicle forward driving working condition, the second quadrant corresponds to a vehicle reverse energy recovery working condition, the third quadrant corresponds to a vehicle reverse driving working condition, and the fourth quadrant corresponds to a vehicle forward energy recovery working condition. Each quadrant comprises two external characteristic curves (N-T curves), i.e., a first N-T curve and a second N-T curve. Each quadrant comprises three working regions, i.e., an A region, a B region and a C region.

[0040] As shown in Figure 3The flowchart illustrates the control method for the oil pump of an oil-cooled drive motor in an electric vehicle according to the present invention. After receiving the power-on signal from the vehicle key, the oil pump control module begins to determine the operating mode of the drive motor. When the drive motor operates in region A of the NT curve, the oil pump is controlled to operate in idle mode; when the drive motor operates in region B of the NT curve, or when the motor temperature t ≥ t... a When the oil pump operates in its rated mode, or when the drive motor operates in region C of the NT curve, or when the motor temperature t ≥ t b When the oil pump operates in peak mode, or when the drive motor operates in stall mode, or when the motor temperature t ≥ t c At this time, the control oil pump operates in extreme mode. The NT curve includes the rated NT curve and the peak N-curve, where the horizontal axis is the N-axis (speed) and the vertical axis is the T-axis (torque); Nmax is the maximum speed; where the value is N... i or -N i Region A is the area enclosed by the straight line, the N-axis, and the rated NT curve; the value is N. i or -N i The area enclosed by the straight line, the N-axis, the rated NT curve, and the straight line with a value of Nmax or -Nmax is designated as region B; region C is the area enclosed by the rated nT curve and the peak NT curve; when the torque and speed parameters of the drive motor determine that it is in region A, B, or C, the corresponding working mode is determined according to the corresponding region, and the corresponding oil pump output flow is provided for oil pump control.

[0041] like Figure 4 As shown, in idle mode, the oil pump outputs at flow rate Q1; in rated mode, it outputs at flow rate Q2; in peak mode, it outputs at flow rate Q3; and in extreme mode, it outputs at flow rate Q4. Idle mode, rated mode, peak mode, and extreme mode increase the output flow rate to improve heat dissipation and match the corresponding mode.

[0042] like Figure 5 As shown in the flowchart of the present invention for determining the working mode of the oil pump of the oil-cooled drive motor in electric vehicles, the specific steps are as follows:

[0043] 1. Begin;

[0044] 2. When the vehicle key is powered on, the fuel pump control module receives the power-on signal from the vehicle key;

[0045] 3. The oil pump control module collects the drive motor temperature, speed, and torque signals in real time and continuously determines the operating mode:

[0046] 3.1 When the conditions are met, the drive motor temperature t is less than the preset temperature t aor the driving motor works in the A area of the N-T curve, i.e. t a or N-T=A, enter step 4 idling mode;

[0047] 3.2, when the condition t a ≤t<t b or N-T=B, enter step 5 rated mode;

[0048] 3.3, when the condition t b ≤t<t c or N-T=C, enter step 6 peak mode;

[0049] 3.4, when the condition t≥t c or the driving motor is in the stall mode, enter step 7 limit mode;

[0050] 4, the oil pump controller controls the oil pump to work in the idling mode, and continuously collects the temperature signal, the speed signal and the torque signal, when t a ≤t<t b or N-T=B, enter step 5 rated mode;

[0051] 5, the oil pump controller controls the oil pump to work in the rated mode, and continuously collects the temperature signal, the speed signal and the torque signal, when t b ≤t<t c or N-T=C, enter step 6 peak mode, when t a and N-T≠B, return to step 4;

[0052] 6, the oil pump controller controls the oil pump to work in the peak mode, and continuously collects the temperature signal, the speed signal and the torque signal, when t c or the motor is in the stall mode, enter step 7 limit mode, when t b and N-T≠C, return to step 5;

[0053] 7, the oil pump controller controls the oil pump to work in the limit mode, and continuously collects the temperature signal, the speed signal and the torque signal, when t c and the motor is not in the stall mode, return to step 6;

[0054] 8, the whole vehicle is powered off;

[0055] 9, end.

[0056] In the embodiment, the first N-T curve is the rated N-T curve, and the second N-T curve is the peak N-T curve. The rated N-T curve corresponds to the rated output capacity of the motor, and the peak N-T curve corresponds to the maximum output capacity of the motor. In the embodiment, the A area is the 0-rated speed N iRegion A is the region between the rated N-T curve and the peak N-T curve, i.e. the region before the inflection point of the rated N-T curve; Region B is the region within the rated N-T curve but not in Region A; Region C is the region within the peak N-T curve but not in Regions A and B, i.e. the region above the rated N-T curve. Figure 2 The abscissa N represents the driving motor speed (unit: rpm), and the ordinate T represents the driving motor torque (unit: N.m), N i represents the rated driving motor speed, N max represents the maximum driving motor speed, T n represents the rated driving motor torque, T max represents the maximum driving motor torque.

[0057] In this embodiment, the temperature t a , t b , t c is increased, which can be calibrated according to actual work, and in this embodiment, t a is set to 30% of the maximum tolerance temperature t max of the driving motor, t b is set to 65% of t max , and t c is set to 85% of t max .

[0058] In this embodiment, Q1 is set to 30% of the maximum output flow rate Q max of the oil pump, Q2 is set to 60% of the maximum output flow rate Q max of the oil pump, Q3 is set to 80% of the maximum output flow rate Q max of the oil pump, and Q4 is set to the maximum output flow rate Q max of the oil pump. Figure 4 The abscissa t represents the driving motor temperature (unit: ℃), and the ordinate Q represents the oil pump output flow rate (unit: L / min).

[0059] In this embodiment, the judgment condition of the driving motor in the locked-rotor mode is that the absolute value of the motor torque ≥ the preset locked-rotor torque T s , the absolute value of the motor speed ≤ the preset locked-rotor speed N s , and the duration t0 ≥ the preset locked-rotor duration t s , i.e. |T| ≥ T s , |N| ≤ N s , and t0 ≥ t s . Wherein T s is generally set to T max , N s is generally set to 50 rpm, and t s is generally set to 3 s.

[0060] In the above technical solution, the N-T curve, the motor working area A, B, C, the motor temperature threshold t a , t b , t c , the oil pump output flow threshold Q1, Q2, Q3, Q4, etc. can be selected and set or fine-tuned according to different motor types, oil pump types, driving habits, driving conditions, environmental temperature, etc. The parameters set in this paper are only illustrative.

[0061] Through the above scheme, the oil pump can be accurately driven according to the current working condition of the driving motor, further improving the cooling effect, while reducing the influence of long-time high-load work of the oil pump on the service life of the oil pump itself and the energy consumption generated by the operation of the oil pump itself.

[0062] Obviously, the specific implementation of the present application is not limited by the above method, as long as various non-essential improvements are made by adopting the method concept and technical scheme of the present application, which are within the protection scope of the present application.

Claims

1. A control method for an oil pump of an oil-cooled drive motor in an electric vehicle, characterized in that: This includes real-time acquisition of the current drive motor status parameters and real-time temperature data, matching the corresponding oil pump control parameters based on the drive motor status parameters and / or the drive motor real-time temperature data, and driving the oil pump based on the oil pump control parameters.

2. The control method for an oil pump of an oil-cooled drive motor in an electric vehicle as described in claim 1, characterized in that: Multiple oil pump operating modes that match the oil pump control parameters and / or temperature data are preset. The corresponding oil pump operating mode is determined based on the current state parameters and / or temperature data of the drive motor. The oil pump is controlled based on the determined oil pump operating mode.

3. The control method for an oil pump of an oil-cooled drive motor in an electric vehicle as described in claim 2, characterized in that: The collected current status parameters of the drive motor include the drive motor's speed signal and torque signal.

4. A control method for an oil pump of an oil-cooled drive motor for an electric vehicle as described in any one of claims 1-3, characterized in that: Multiple oil pump operating modes are each matched with different oil pump output flow rates; after entering an oil pump operating mode, the corresponding oil pump output flow rate is used to control the oil pump.

5. A control method for an oil pump of an oil-cooled drive motor for an electric vehicle as described in any one of claims 1-3, characterized in that: The current oil pump operating mode is determined based on the collected speed and torque signals of the drive motor, as well as the NT curve of the external characteristics of the drive motor, and / or based on the temperature.

6. A control method for an oil pump of an oil-cooled drive motor for an electric vehicle as described in any one of claims 1-3, characterized in that: The oil pump operates in four modes: a first mode, a second mode, a third mode, and a fourth mode. In each of these modes, the oil pump's output flow rate is controlled to be Q1, Q2, Q3, and Q4, respectively; the magnitude of the output flow rate is set to Q1. <Q2<Q3<Q4。 7. The control method for an oil pump of an oil-cooled drive motor in an electric vehicle as described in claim 6, characterized in that: When the drive motor temperature t is less than the preset temperature t a When the drive motor is operating in the A region of the NT curve, it is determined that the first mode of the oil pump operation mode has been entered. In the first mode, the oil pump is controlled according to the output flow rate Q1. The A region of the NT curve refers to the area enclosed by the rated NT curve and the N coordinate from speed 0 to rated speed Ni.

8. A control method for an oil pump of an oil-cooled drive motor for an electric vehicle as described in claim 6 or 7, characterized in that: When the motor drive temperature t is at t a ≤t<t b When the drive motor is operating in region B of the NT curve, it is determined that the second mode of the oil pump operation mode has been entered. In the second mode, the oil pump is controlled according to the output flow rate Q2. Region B in the NT curve refers to the part of the area enclosed between the rated NT curve and the N coordinate, excluding region A.

9. A control method for an oil pump of an oil-cooled drive motor for an electric vehicle as described in claim 6 or 7, characterized in that: When the motor drive temperature t is at t b ≤t<t c When the drive motor is operating in region C of the NT curve, it is determined that the pump has entered the third mode of operation. In the third mode, the pump is controlled according to the output flow rate Q3. Region C in the NT curve refers to the area between the peak NT curve and the rated NT curve.

10. A control method for an oil pump of an oil-cooled drive motor for an electric vehicle as described in claim 6 or 7, characterized in that: When the motor drive temperature t is t≥t c If the drive motor is in stall mode, it is determined that the oil pump is in the fourth mode of operation. In the fourth mode, the oil pump is controlled according to the output flow rate Q4.

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