Temperature rise performance test and temperature rise duration optimization method for vehicle air-cooled motor

Abstract

The invention discloses a temperature rise performance test and temperature rise duration optimization method for a vehicle air-cooled motor, which utilizes a whole vehicle rotating hub test room to formulate an equivalent test room driving working condition according to a user driving working condition so as to carry out a motor temperature rise performance test, and provides a motor temperature rise duration optimization method. The whole vehicle rotating hub test room is used for replacing a real road test, the limitation of a test site and the environment temperature can be avoided, the working difficulty is reduced, a target compression ratio engine is screened, and the consistency and accuracy of test conditions are guaranteed; a user equivalent use condition is formulated, a whole vehicle rotating hub test is adopted, and the problem that a standard test method does not exist is solved; two motor temperature rise duration optimization methods are provided.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy vehicle performance testing and performance optimization, and specifically relates to a method for temperature rise performance testing and temperature rise duration optimization of a vehicle air-cooled motor, and is especially suitable for natural air-cooled motors of A00-class pure electric vehicles. Background Art

[0002] A00-class pure electric vehicles generally use natural air-cooled motors, which do not have forced cooling devices. When the ambient temperature is high and the vehicle has been running for a long enough time under conditions with heavy motor load, the heat taken away by the natural wind can no longer be balanced with the heat emitted by the motor itself, and the motor temperature will continue to rise. When the motor temperature reaches the protection limit, the motor power output will be limited or cut off to avoid excessive motor temperature, insulation failure or magnetic steel demagnetization, which will cause permanent damage to the motor. However, when the vehicle enters the over-temperature protection, it will affect the customer's normal driving and suddenly lose power. For vehicles that are in motion, there are certain safety risks. Therefore, the continuous high-load driving time of the vehicle should be verified during the vehicle development stage to ensure that there will be no large-scale complaints after the vehicle model is put on the market.

[0003] At present, for naturally air-cooled motors, only fixed-speed full-load temperature rise tests are carried out on the test bench during the development stage, and the general criterion is that the temperature rise does not exceed 150°C (the power limit temperature of the whole vehicle motor) in 30 seconds. In the actual development process, it was found that this evaluation method is difficult to cover the actual operating conditions of users. Under some extreme conditions that customers may use, motor overheating problems will still occur, which cannot meet the needs of some users. In the road tests during the development process, due to the limitations of the road slope and length of the test site, it is also difficult to effectively restore the customer's extreme conditions. Therefore, the existing test methods cannot effectively judge whether the motor performance can meet the needs of the whole vehicle, which is prone to after-sales complaints. Summary of the invention

[0004] In order to solve the problem that the existing natural air-cooled motor of new energy vehicles enters over-temperature protection when running for a long time under high load, the present invention provides a method for testing the temperature rise performance and optimizing the temperature rise time of an automotive air-cooled motor. By utilizing a whole vehicle hub test laboratory and formulating equivalent laboratory driving conditions according to user driving conditions, the motor temperature rise performance test is carried out, and a method for optimizing the motor temperature rise time is provided.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A method for testing the temperature rise performance of an air-cooled motor for a vehicle and optimizing the temperature rise time comprises the following steps:

[0007] Step 1: Use the vehicle hub test room to develop equivalent laboratory driving conditions based on the user's driving conditions and conduct motor temperature rise performance tests;

[0008] Step 2: Optimize the motor temperature rise time by increasing motor performance redundancy or reducing vehicle load.

[0009] Furthermore, the step 1 comprises:

[0010] S1. Collection of vehicle resistance curve;

[0011] S2. Formulate test conditions: formulate the motor temperature rise test conditions on the rotor hub in the laboratory according to the user's driving conditions;

[0012] S3. Conduct vehicle laboratory hub test using the vehicle hub test laboratory;

[0013] S4. Experimental evaluation.

[0014] Furthermore, the step S1 comprises:

[0015] The vehicle road spectrum is collected using a test vehicle to obtain the vehicle resistance curve, which is then input into the vehicle hub test bench to simulate the actual state of the vehicle driving on the road.

[0016] Furthermore, in step S2, the motor temperature rise test condition includes:

[0017] 1) The ambient temperature is 40°C, the ambient humidity is less than 20%, and the initial temperature of the motor is the same as the ambient temperature;

[0018] 2) The vehicle is loaded according to the designed full load, and the hub slope is set to the maximum designed climbing grade of the vehicle;

[0019] 3) Driving conditions.

[0020] Furthermore, in step S2, the driving conditions include:

[0021] a. Accelerate at full throttle from 0 speed to the vehicle's stable speed;

[0022] b. After reaching a stable speed, continue driving at full throttle;

[0023] c. When the power limit indicator light appears on the vehicle, the speed will automatically decrease. At this time, you still need to maintain full throttle until the speed drops to 0, and then the test ends.

[0024] Furthermore, the step S3 comprises:

[0025] The test equipment is connected, and the data acquisition equipment is connected to the test vehicle to record the vehicle operation data in real time; and the test is performed according to the test conditions formulated in step S2.

[0026] Furthermore, the vehicle operation data includes at least: time, ambient temperature, vehicle speed, motor speed, motor torque, motor current, and motor input voltage.

[0027] Furthermore, the step S4 comprises:

[0028] The time from the start of the vehicle to the time when the over-temperature and power limit indicator light on the vehicle instrument is turned on is the effective duration of the vehicle's continuous climbing; the equivalent duration of continuous climbing in the test laboratory should be no less than 150s.

[0029] Furthermore, the step 2 comprises:

[0030] Method 1 for optimizing the motor temperature rise time: Increase motor performance redundancy:

[0031] By modifying the electromagnetic scheme of the motor, the peak current I and resistance R of the motor are reduced while ensuring that the motor power and torque remain unchanged; the degree of optimization is preliminarily determined through the motor temperature rise simulation, and then a prototype is made according to the new electromagnetic scheme, installed on the vehicle, and step 1 is repeated to evaluate the effectiveness of the optimization scheme;

[0032] The second method to optimize the motor temperature rise time is to reduce the vehicle load and sacrifice some power to extend the motor temperature rise time.

[0033] The present invention has the following advantages:

[0034] 1. Using a complete vehicle rotating hub test room instead of a real road test can avoid the limitations of the test site and ambient temperature, reduce the difficulty of work, screen the target compression ratio engine, and ensure the consistency and accuracy of the test conditions;

[0035] 2. The vehicle hub test room can simulate a certain slope and the continuous climbing process of the vehicle, thereby overcoming the problems of discontinuous slopes and non-fixed slopes on real roads.

[0036] 3. We developed equivalent user operating conditions and adopted the whole vehicle rotation test to solve the problem of no standard test method;

[0037] 4. Two methods for optimizing the motor temperature rise time are given. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0039] Figure 1This is a flow chart of a method for testing the temperature rise performance and optimizing the temperature rise time of a vehicle air-cooled motor according to Embodiment 1 of the present invention;

[0040] Figure 2 This is a schematic diagram of the principle of the whole vehicle hub stand described in Example 1 of the present invention. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments:

[0042] Example

[0043] like Figure 1 As shown, this embodiment is a method for testing the temperature rise performance and optimizing the temperature rise time of an air-cooled motor for a vehicle, comprising the following steps:

[0044] Step 1: Use the vehicle hub test room to develop equivalent laboratory driving conditions based on the user's driving conditions and conduct motor temperature rise performance tests, including:

[0045] S1. Vehicle resistance curve collection:

[0046] Use the test vehicle to collect the vehicle road spectrum, obtain the accurate vehicle resistance curve, and input it into the vehicle hub test bench, such as Figure 2 As shown in the figure, it is used to simulate the real state of a vehicle driving on the road. Different models have different resistance curves due to different characteristic parameters such as vehicle weight, wind resistance, and tire rolling resistance, so road spectra need to be collected separately.

[0047] S2. Establish test conditions:

[0048] According to the user's driving conditions, the motor temperature rise test conditions on the laboratory hub are formulated, and the motor temperature rise test conditions include:

[0049] 1) The ambient temperature is 40°C, the ambient humidity is less than 20%, and the initial temperature of the motor is the same as the ambient temperature;

[0050] 2) The vehicle is loaded according to the designed full load, and the hub slope is set to the maximum designed climbing grade of the vehicle;

[0051] 3) Driving conditions, including:

[0052] a. Accelerate at full throttle from 0 speed to the vehicle's stable speed;

[0053] b. After reaching a stable speed, continue driving at full throttle;

[0054] c. When the power limit indicator light appears, the vehicle speed will automatically decrease. At this time, you still need to maintain full throttle until the speed drops to 0, and then the test ends;

[0055] S3. Carry out the vehicle test in the vehicle test room:

[0056] Test equipment connection: connect the data acquisition equipment to the test vehicle to record the vehicle operation data in real time; the vehicle operation data includes at least: time, ambient temperature, vehicle speed, motor speed, motor torque, motor current, motor input voltage, and other parameters can be added and recorded as needed;

[0057] The test is performed according to the test conditions established in step S2.

[0058] S4. Test evaluation:

[0059] The time from the vehicle starting to the time the over-temperature power limit indicator light appears on the vehicle instrument is the effective duration of the vehicle's continuous climbing. Based on market customer usage analysis, the equivalent duration of continuous climbing in the laboratory should be no less than 150s.

[0060] Step 2: Optimize the motor temperature rise time:

[0061] If the motor temperature rise time is lower than the set index, measures should be taken to extend the temperature rise time.

[0062] Since the motor temperature rise is mainly caused by the heating of the motor winding, the heating power formula is:

[0063] P=I 2 *R,

[0064] In the formula, P is the heating power, I is the current, and R is the wire resistance;

[0065] The temperature rise is proportional to the time t;

[0066] Therefore, the time it takes for the motor to reach the protective temperature can be extended by reducing the heat generation power of the motor itself to increase the motor performance redundancy, or by reducing the load used by the vehicle (i.e., motor power) and sacrificing some power. This can achieve the purpose of increasing the motor temperature rise time.

[0067] Method 1 for optimizing the motor temperature rise time: increasing motor performance redundancy

[0068] By modifying the electromagnetic scheme of the motor, the peak current I and resistance R of the motor can be reduced while ensuring that the motor power and torque remain unchanged. The degree of optimization can be preliminarily determined through the motor temperature rise simulation, and then a prototype can be made according to the new electromagnetic scheme, installed on the vehicle, and steps S1 to S4 can be repeated to evaluate the effectiveness of the optimization scheme.

[0069] In this embodiment, under the premise of ensuring that the motor power and torque remain unchanged, the motor peak current I is reduced from 500A to 350A, and the resistance R is reduced from 1000Ω to 500Ω. Through the motor temperature rise simulation, the 30s temperature rise of the motor at 3000 rpm full load is reduced from 120°C to 70 degrees Celsius. The new electromagnetic scheme motor is installed on the vehicle and steps 1 to 4 are repeated. The time to reach the power limit is increased from 100s to 160s.

[0070] The advantage of method one is that it can significantly improve the motor temperature rise time, but the disadvantage is that the motor cost increases significantly.

[0071] Therefore, when the difference between the tested temperature rise time and the target time is not large, you can try the second method to optimize the motor temperature rise time: reduce the vehicle load and sacrifice some power to achieve the purpose of extending the motor temperature rise time.

[0072] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for testing the temperature rise performance of an air-cooled motor for a vehicle and optimizing the temperature rise time, characterized in that: The following steps are involved: Step 1: Use the vehicle hub test room to develop equivalent laboratory driving conditions based on the user's driving conditions and conduct motor temperature rise performance tests; Step 2: Optimize the motor temperature rise time by increasing motor performance redundancy or reducing vehicle load.

2. A method for testing the temperature rise performance and optimizing the temperature rise time of an air-cooled motor for a vehicle as claimed in claim 1, characterized in that: The step one comprises: S1. Collection of vehicle resistance curve; S2. Formulate test conditions: formulate the motor temperature rise test conditions on the rotor hub in the laboratory according to the user's driving conditions; S3. Conduct vehicle laboratory hub test using the vehicle hub test laboratory; S4. Experimental evaluation.

3. A method for testing the temperature rise performance and optimizing the temperature rise time of an air-cooled motor for a vehicle as claimed in claim 2, characterized in that: The step S1 comprises: The vehicle road spectrum is collected using a test vehicle to obtain the vehicle resistance curve, which is then input into the vehicle hub test bench to simulate the actual state of the vehicle driving on the road.

4. A method for testing the temperature rise performance and optimizing the temperature rise time of an air-cooled motor for a vehicle as claimed in claim 2, characterized in that: In step S2, the motor temperature rise test condition includes: 1) The ambient temperature is 40°C, the ambient humidity is less than 20%, and the initial temperature of the motor is the same as the ambient temperature; 2) The vehicle is loaded according to the designed full load, and the hub slope is set to the maximum designed climbing grade of the vehicle; 3) Driving conditions.

5. A method for testing the temperature rise performance and optimizing the temperature rise time of an air-cooled motor for a vehicle as claimed in claim 4, characterized in that: In step S2, the driving conditions include: a. Accelerate at full throttle from 0 speed to the vehicle's stable speed; b. After reaching a stable speed, continue driving at full throttle; c. When the power limit indicator light appears on the vehicle, the speed will automatically decrease. At this time, you still need to maintain full throttle until the speed drops to 0, and then the test ends.

6. A method for testing the temperature rise performance and optimizing the temperature rise time of an air-cooled motor for a vehicle as claimed in claim 2, characterized in that: The step S3 comprises: The test equipment is connected, and the data acquisition equipment is connected to the test vehicle to record the vehicle operation data in real time; and the test is performed according to the test conditions formulated in step S2.

7. A method for testing the temperature rise performance and optimizing the temperature rise time of an air-cooled motor for a vehicle as claimed in claim 6, characterized in that: The vehicle operation data at least includes: time, ambient temperature, vehicle speed, motor speed, motor torque, motor current, and motor input voltage.

8. A method for testing the temperature rise performance and optimizing the temperature rise time of an air-cooled motor for a vehicle as claimed in claim 2, characterized in that: The step S4 comprises: The time from the start of the vehicle to the time when the over-temperature and power limit indicator light on the vehicle instrument is turned on is the effective duration of the vehicle's continuous climbing; the equivalent duration of continuous climbing in the test laboratory should be no less than 150s.

9. A method for testing the temperature rise performance and optimizing the temperature rise time of an air-cooled motor for a vehicle as claimed in claim 1, characterized in that: The second step comprises: Method 1 for optimizing the motor temperature rise time: Increase motor performance redundancy: By modifying the electromagnetic scheme of the motor, the peak current I and resistance R of the motor are reduced while ensuring that the motor power and torque remain unchanged; the degree of optimization is preliminarily determined through the motor temperature rise simulation, and then a prototype is made according to the new electromagnetic scheme, installed on the vehicle, and step 1 is repeated to evaluate the effectiveness of the optimization scheme; The second method to optimize the motor temperature rise time is to reduce the vehicle load and sacrifice some power to extend the motor temperature rise time.

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