An end-of-line method for determining the efficiency of automotive modules.

Abstract

A method is provided for measuring mechanical losses in an automobile module (100). The automobile module (100) comprises an electric motor (110), the method comprising: 0 ), changing the control of the electric motor (110) to an open circuit mode (S10), observing (S20) an operating parameter (201) associated with deceleration of the vehicle module (100), and determining mechanical losses of the vehicle module based on the operating parameter (201).

Description

[Technical field]

[0001] The present invention relates generally to a method for determining the efficiency of a vehicle module, and more particularly to an end-of-line method for determining characteristics related to mechanical losses in a vehicle module comprising at least an electric motor. [Background technology]

[0002] Reducing time to market is one of the most important requirements in the electric vehicle industry. As part of the manufacturing process, producers must ensure that efficiency is met by conducting end-of-line (EOL) testing on every unit that leaves the factory, i.e. testing of the product manufactured at the final stage of the production line. EOL testing not only ensures that the unit or manufactured product is manufactured according to the proper specifications, but also provides an indication of when to start troubleshooting to reduce failure rates.

[0003] Standard EOL testing involves the measurement of drive-specific values ​​for current, voltage, torque and speed to evaluate the efficiency of the test object at defined operating points. This can be a complex, unreliable and time-consuming task, requiring separate, often unique, dedicated test equipment, reducing test throughput and increasing costs. Especially for complex products, e.g. electric motor modules with integrated gearboxes or similar, available end-of-line test procedures are unable to determine the mechanical losses of individual sub-modules, such as integrated gearboxes, in an efficient manner.

[0004] Therefore, there is a need for improved EOL testing in automotive modules. Summary of the Invention

[0005] It is an object of the present invention to solve or at least alleviate the problems associated with the prior art. This object is achieved by the techniques set out in the accompanying independent claims, with preferred embodiments defined in the associated dependent claims.

[0006] According to a first aspect, an end-of-line method for measuring mechanical losses of a vehicle module including an electric motor is provided, the method including the steps of controlling the electric motor to operate at a particular speed, switching control of the electric motor to an active open mode, observing an operating parameter associated with deceleration of the vehicle module, and determining mechanical losses of the vehicle module based on the operating parameter.

[0007] Thus, a method for measuring mechanical losses of an automobile module is provided, the method being designed to be performed in association with an automobile module at the end of a production line, the automobile module comprising an electric motor, the method comprising the steps of: i) controlling the electric motor to operate at a specific speed, ii) changing the control of the electric motor to an open circuit mode by leaving the electric motor wiring open and / or electrically disconnecting the motor phases from the controller, iii) observing an operating parameter related to the rotational speed of the electric motor and associated with deceleration of the automobile module, and iv) determining the mechanical losses of the automobile module based on the operating parameter.

[0008] The operating parameter may relate to the rotational speed of the electric motor.

[0009] Observing the operating parameters may include determining a characteristic response of the vehicle module.

[0010] The characteristic response may relate to at least one of the velocity drop during a predetermined time interval, the derivative of the velocity, and / or the time it takes to reach a predetermined velocity.

[0011] The characteristic response includes a first predetermined time interval and a second predetermined time interval.

[0012] The method may further comprise the step of comparing the determined characteristic response to a reference characteristic response.

[0013] The electric motor may be connected to the gear assembly via a disconnect coupling, and the method may further include disconnecting the disconnect coupling prior to changing control of the electric motor to the open circuit mode.

[0014] The steps of controlling the electric motor to operate at a particular speed, changing control of the electric motor to an open circuit mode, and observing operating parameters associated with deceleration of the vehicle module may be performed as a first test cycle when the disconnect coupling is connected and as a second test cycle when the disconnect coupling is disconnected, and the method may further include determining mechanical losses of the gear assembly based on a comparison between the determined operating parameters.

[0015] The electric motor may be connected to a multi-stage gear assembly, and the method may further include shifting a stage of the gear assembly prior to the step of changing control of the electric motor to the open circuit mode.

[0016] The steps of controlling the electric motor to operate at a particular speed, changing the control of the electric motor to an open circuit mode, and observing operating parameters associated with deceleration of the vehicle module may be further performed as a third test cycle when a stage of the gear assembly is shifted, and the method further includes determining mechanical losses at a particular gear assembly stage based on a comparison between the determined operating parameters.

[0017] In general, all terms used in the claims should be interpreted according to their ordinary meaning in the art, unless expressly defined otherwise herein. All references to "a / an / the [parameter, characteristic response, step, etc.]" should be openly interpreted as referring to at least one instance of that parameter, characteristic response, step, etc., unless expressly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless expressly stated otherwise. [Brief description of the drawings]

[0018] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0019] [Figure 1a] 1 is a flow chart of an end-of-line method according to different embodiments. [Figure 1b] 1 is a flow chart of an end-of-line method according to different embodiments. [Figure 1c] 1 is a flow chart of an end-of-line method according to different embodiments. [Diagram 2] 1 is a schematic diagram of a vehicle module according to different embodiments; [Diagram 3] 1 is a schematic diagram of a vehicle module according to different embodiments; [Figure 4] 1 is a schematic diagram of a vehicle module according to different embodiments; [Diagram 5] FIG. 2 is a schematic diagram of a characteristic response obtained from a method according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown, however, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather these embodiments are provided for thoroughness and completeness and to fully convey the scope of the invention to those skilled in the art.

[0021] It will be understood that the invention is not limited to the embodiments shown, and therefore, certain modifications and variations are contemplated to be within the scope of the invention as defined exclusively by the appended claims.

[0022] Starting from Fig. 1a, an end-of-line method for measuring mechanical losses in a vehicle module 100 (see Figs. 2-4) according to an embodiment is provided. The vehicle module 100 comprises at least an electric motor 110, as shown in Fig. 2. The method according to the embodiment shown in Fig. 1a includes the steps of controlling the electric motor 110 S09 to operate at a certain speed v0, changing the control of the electric motor 110 to an open circuit mode S10, observing operating parameters 201 (see Fig. 5) associated with deceleration of the vehicle module 100 S20, and determining mechanical losses as a measure of efficiency in the vehicle module based on the operating parameters 201.

[0023] By electric motor 110 operating at a particular speed v0 it is meant that rotor 111 of motor 110 is rotating at a particular speed v0 measured, for example, in revolutions per minute (rpm). Step S10 of changing the control of electric motor 110 to an open circuit mode may include leaving electric motor wires open and / or electrically disconnecting motor phases from the controller.

[0024] In general, open circuit mode of electric motor 110 refers to any situation in which the circuit between the power source and electric motor 110 is interrupted or disconnected. In other words, the electrical path is interrupted and current cannot flow through electric motor 110. When electric motor 110 is in open circuit mode, it does not receive the electrical energy necessary to perform its normal function.

[0025] When the electric motor 110 is changed to open circuit mode, the rotor 111 continues its rotational motion at a gradually decreasing speed, i.e., coast mode, due to its own inertia. The rotational motion of the rotor 111 is not actively driven by the electric motor 110 in open circuit mode, but rather is driven by the inertia of the electric motor 110 and possibly other rotating components of the vehicle module 100. Braking forces due to mechanical loss factors such as friction and splash further slow the rotational speed of the rotor 111, increasing the deceleration.

[0026] The operating parameter 201 may be related to the rotational speed of the electric motor 110. The operating parameter 201 may be, for example, the motor position, and therefore the speed, measured by a position sensor on the rotor 111 of the motor 110.

[0027] According to the embodiment shown in Fig. 1a, the step of determining the mechanical losses of the vehicle module is carried out by a step S30 of determining a characteristic response 200 of the vehicle module 100. An example of such a characteristic response 200 is shown in Fig. 5, where an operating parameter 201, which is the rotational speed, is plotted against time. As can be seen from Fig. 5, the speed of the electric motor is initially at a certain speed v0. A step S10 of changing the control of the electric motor 110 to an open circuit mode at t0 of the diagram causes the speed to decelerate towards zero.

[0028] The characteristic response 200 may relate to at least one of the speed drop during a predetermined time interval, the derivative of the speed, and / or the time it takes to reach a predetermined speed. The characteristic response 200 may relate, for example, to the speed drop derivative over an interval, or the total time to stop.

[0029] The characteristic response 200 is shown in Figure 5. a , t b and a predetermined second time interval t c , t d The different intervals of the characteristic response may be associated with different mechanical losses in the vehicle module 100. a , t b The speed reduction Δv=v a -v b or its derivative may be related, for example, to splash loss, and is c , t d The speed reduction Δv=v c -v d may be related to friction in seals and bearings.

[0030] Returning to the embodiment shown in FIG. 1a, the method further comprises a step S40 of comparing the determined characteristic response 200 with a reference characteristic response 210 (see FIG. 5). The reference characteristic response 210 may for example be an ideal characteristic response or an acceptable characteristic response. The reference characteristic response 210 may for example be obtained by modeling or by measuring a reference automobile module. The difference between the determined characteristic response 200 and the reference characteristic response 210 may be calculated globally, at a particular time, or over a first and second time interval t a , t b , t c , t d It may be determined at a predetermined interval.

[0031] If the determined difference exceeds an acceptable threshold, the vehicle module 100 may be deemed unacceptable for not meeting end-of-line requirements. a , t bIf the determined characteristic response 200 deviates from the baseline characteristic response 201 at an unacceptable level during the second time interval t c , t d If the friction loss deviates from the baseline characteristic response 201 at an unacceptable level, then the friction loss may be deemed unacceptable.

[0032] Advantageously, because the only input parameters required to determine the mechanical losses are the operating parameters, which are easily observed by signals already available from the electric motor 110, the mechanical losses of the automotive module 100 can be measured with high test throughput without time-consuming tasks or the need for separate test equipment.

[0033] Now referring to Fig. 1b, an end-of-line method for measuring mechanical losses in a vehicle module 100 according to another embodiment is provided. The vehicle module 100 comprises an electric motor 110 connected to a gear assembly 140 via a disconnect coupling 130 as shown in Fig. 3. The method according to the embodiment shown in Fig. 1b further comprises a step S13 of disconnecting the disconnect coupling 130.

[0034] The step S09 of controlling the electric motor 110 to operate at a certain speed v0, the step S10 of changing the control of the electric motor 110 to an active open mode, and the step S20 of observing the operating parameters 201 associated with the deceleration of the vehicle module 100 may be performed as a first test cycle S01 when the disconnection coupling 130 is connected, and as a second test cycle S02 when the disconnection coupling 130 is disconnected. This results in a first characteristic response 200 for the entire vehicle module, and a second characteristic response 220 for the vehicle module when the gear assembly 140 is disconnected. The method may further include a step of determining a resulting third characteristic response 230 by comparing the already determined characteristic responses 200, 220, and a step of determining a contribution from a component downstream of the disconnection coupling 130 (i.e., the gear assembly 140 in this embodiment). This may be performed, for example, by subtracting the second characteristic response 220 from the first characteristic response 200. From the third characteristic response 230, the efficiency of the gear assembly 140 can be determined.

[0035] As previously mentioned, the step S20 of observing the operating parameters 201 is followed by a step S30 of determining a characteristic response 200 of the entire vehicle module 100 after a first test cycle, and a step S30 of determining a characteristic response 220 of the parts of the vehicle module 100 after a second test cycle. From these two characteristic responses 200, 220, a resulting third characteristic response 230 is determined, which is representative of the mechanical losses of the parts of the vehicle module 100 that are disconnected during the second test cycle.

[0036] To determine the end-of-line performance of the cuttable part of the automobile module 100, a comparison between the observed operating parameters can be made from the resulting third characteristic response 230 by comparing this third characteristic response 230 to a reference characteristic response 210 that represents the characteristic response 210 of the cuttable part of the automobile module 100 when mechanical losses are at an acceptable level.

[0037] The mechanical losses of the gear assembly 140 are typically small and therefore difficult to test in an acceptable time using standard EOL equipment. By performing a first test cycle S01 when the disconnect coupling 130 is connected and a second test cycle S02 when the disconnect coupling 130 is disconnected, it becomes easy to characterize the efficiency of the gear assembly 140 by looking at the difference 230 of the characteristic responses 200, 220 and comparing the difference with the reference characteristic response 210. Thus, it is ensured that the mechanical losses of the gear assembly 140 are measured in the method of the present invention to determine the efficiency of the gear assembly 140.

[0038] Now referring to Fig. 1c, an end-of-line method for measuring mechanical losses of an automobile module 100 according to another embodiment is provided. The electric motor 110 is connected to a multi-stage gear assembly 140 as shown in Fig. 4. The method according to the embodiment shown in Fig. 1c further comprises a step S17 of shifting stages of the gear assembly 140 to determine the efficiency of the different gear stages of the gear assembly 140.

[0039] The multi-stage gear assembly 140 may include a shifting means 140a, and the shifting step S17 may be performed by engaging the shifting means 140a.

[0040] The step S09 of controlling the electric motor 110 to operate at a particular speed v0, the step S10 of changing the control of the electric motor 110 to an open circuit mode, and the step S20 of observing the operating parameters 201 associated with the deceleration of the vehicle module 100 can also be further performed as a third test cycle S03, and possibly further test cycles, when the stage of the gear assembly 140 is shifted. This results in a first characteristic response 200 of the entire vehicle module when the gear assembly 140 is in the first gear stage, and a second characteristic response 220 of the entire vehicle module when the gear assembly 140 is in the second gear stage. The method may further comprise a step of determining a resulting third characteristic response 230 by comparing the already determined characteristic responses 200, 220, and a step of determining a characteristic response for a particular gear stage. This can be performed, for example, by subtracting the second characteristic response 220 from the first characteristic response 200. From the third characteristic response 230 it is possible to determine the efficiency of the second gear stage of the gear assembly 140.

[0041] As previously mentioned, the step S20 of observing the operating parameters 201 is followed by a step S30 of determining a characteristic response 200 of the entire vehicle module 100 when the gear assembly 140 is in a first gear stage after a first test cycle, and a step S30 of determining a characteristic response 220 of the entire vehicle module 100 when the gear assembly is in a second gear stage after a second test cycle. From these two characteristic responses 200, 220, a third characteristic response 230 can be determined, which is representative of mechanical losses of parts of the vehicle module 100 that are used in the first gear stage but not in the second gear stage.

[0042] A comparison between the observed operating parameters can be performed from the resulting third characteristic response 230 by comparing this third characteristic response 230 to the reference characteristic response 210 to determine the end-of-line performance of the different gear stages of the vehicle module. If desired, each measured characteristic response 200, 220 may be compared individually to one or more reference characteristic responses 210 to determine the efficiency of each gear stage.

[0043] The controlling step S09, varying step S10, and observing step S20 may be further performed as a fourth test cycle, such as when a stage of the gear assembly is shifted once more. The observing step S20 may be performed by comparing further characteristic responses for further observed stages of the multi-stage gear assembly 140.

[0044] The mechanical losses of the multi-stage gear assembly 140 are difficult to test in an acceptable time using standard EOL equipment. By performing the first test cycle S01 when the gear assembly 140 is at a certain stage, and as the stage of the third test cycle S03 of the gear assembly 140 shifts, it becomes easy to characterize the gear assembly 140 by looking at the difference in the characteristic responses 200, 230 or by comparing the characteristic responses 200, 230 individually. Thus, in the method of the present invention, it is ensured that the mechanical losses of different stages of the multi-stage gear assembly 140 are measured.

[0045] Although the present invention has been described with reference to the specific examples shown in the drawings, it should be noted that several embodiments or elements thereof may be combined. For example, one embodiment of the vehicle module 100, not shown, may include a disconnect 130 and a multi-stage gear assembly 140.

[0046] Similarly, an embodiment of an end-of-line method for measuring mechanical losses of an automotive module 100 (not shown) may include performing a first test cycle S01, a second test cycle S02, and a third test cycle S03. The step S40 of comparing the characteristic responses may refer to any combination of the characteristic responses 200, 210, 220, 230.

[0047] As shown in Figures 3 and 4, the vehicle module 100 may include a rotating shaft 120 connected to the electric motor 110. As further shown in Figures 3 and 4, the vehicle module 100 may include a second disconnect 160 connected to the output shaft 150 of the gear assembly 140. Before performing a test cycle, the second disconnect 160 may be disconnected so that the disclosed sub-modules of the vehicle module 100 are disengaged from other undisclosed sub-modules and the rotational motion of the rotor 100 is driven only by the inertia of the disclosed sub-modules, including the electric motor 110 and possibly the gear assembly 140, in an open circuit mode. The advantage of this is that the mechanical losses of the vehicle module 100 can be measured with a high test throughput without the need for time-consuming operations or separate equipment stations.

[0048] 3, the vehicle module 100 is preferably connected to a controller 170 configured to control the operation of the electric motor 110, i.e., to accelerate the electric motor 110 to an initial certain speed v0, and to observe at least one operating parameter associated with the deceleration of the vehicle module 100. For observation, the controller 170 may receive speed data from a resolver 112 or any similar device.

[0049] The method according to the present invention is applicable to, but not limited to, all electric motor, combined transmission, integrated drive module, electric drive module, and hybrid drive applications.

[0050] From the foregoing description, while various embodiments of the present invention have been described and illustrated, the present invention is not limited thereto but may be embodied in other ways within the scope of the subject matter defined in the following claims.

Claims

1. A method for measuring mechanical losses of an automobile module (100) comprising an electric motor (110) in an end-of-line manufacturing process, comprising: At a specific speed (v ０ (S09) controlling the electric motor (110) to operate at changing (S10) the control of the electric motor (110) to an open circuit mode by leaving the electric motor wiring open and / or electrically disconnecting a motor phase from a control device; Observing (S20) operational parameters (201) associated with deceleration of the vehicle module (100); determining mechanical losses of said vehicle module based on said operating parameters (201); A method comprising:

2. The method of claim 1 , wherein the operating parameter (201) is related to a rotational speed of the electric motor (110).

3. The method according to claim 1 or 2, wherein the step (S20) of observing operating parameters (201) comprises the step (S30) of determining a characteristic response (200) of the vehicle module (100).

4. 4. The method of claim 3, wherein the characteristic response (200) relates to at least one of a velocity drop during a predetermined time interval, a derivative of the velocity, and / or a time taken to reach a predetermined velocity.

5. The characteristic response (200) is measured over a first predetermined time interval (t ａ , t ｂ ) and a predetermined second time interval (t ｃ , t ｄ 5. The method of claim 3 or 4, comprising:

6. The method according to any one of claims 3 to 5, wherein the method further comprises a step (S40) of comparing the determined characteristic response (200) with a reference characteristic response (210).

7. The electric motor (110) is connected to a gear assembly (140) via a disconnect coupling (130); The method according to any one of claims 1 to 6, further comprising the step (S13) of disconnecting the disconnect coupling (130) before the step (S10) of changing the control of the electric motor (110) to an open circuit mode.

8. At a specific speed (v ０ a step of controlling (S09) the electric motor (110) to operate in a closed circuit mode, a step of changing (S10) the control of the electric motor (110) to an open circuit mode, and a step of observing (S20) an operating parameter (201) associated with the deceleration of the vehicle module (100) are performed as a first test cycle (S01) when the disconnection coupling (130) is connected and as a second test cycle (S02) when the disconnection coupling (130) is disconnected; 8. The method of claim 7, further comprising determining mechanical losses of the gear assembly based on a comparison between the observed operating parameters (201).

9. 9. The method according to any one of claims 1 to 8, wherein the electric motor (110) is connected to a multi-stage gear assembly (140), the method further comprising the step (S17) of shifting a stage of the gear assembly (140) before the step (S10) of changing the control of the electric motor (110) to an open circuit mode.

10. At a specific speed (v ０ a step of controlling (S09) the electric motor (110) to operate in an open circuit mode, a step of changing (S10) the control of the electric motor (110) to an open circuit mode, and a step of observing (S20) an operating parameter (201) associated with the deceleration of the vehicle module (100) are further performed as a third test cycle (S03) when the stage of the gear assembly (140) is shifted; 10. The method of claim 9, further comprising determining mechanical losses at a particular gear assembly stage based on a comparison between the observed operating parameters (201).

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