Method for detecting blockage fault of main oil duct in transmission EOL off-line test

Abstract

The invention discloses a method for detecting a blockage fault of a main oil duct in a transmission EOL off-line test, and relates to the technical field of EOL tests. The method comprises the following steps: decoupling an EOL off-line test mode and a whole vehicle power-on self-test mode on a transmission controller; when the transmission controller is powered on, mode identification is carried out firstly, and if the mode is an EOL mode, a control strategy of the controller on the transmission in the EOL off-line test mode is executed; and if the vehicle is in the whole vehicle power-on self-test mode, executing a control strategy of the controller on the transmission in the whole vehicle mode. In the EOL test process, the detection capability can be improved by changing EOL test conditions and parameters, and meanwhile, the use of the whole vehicle is not affected. By increasing the rotating speed of the electronic oil pump in a non-pipe-opening state in the EOL off-line testing process, the problem of blockage of the main oil duct of the transmission can be effectively recognized.

Description

Technical Field

[0001] The present invention relates to the technical field of EOL testing, and in particular to a method for detecting a main oil channel blockage fault in a transmission EOL test. Background Art

[0002] End-of-line (EOL) testing is the final stage of quality control for transmission assemblies. It requires testing key transmission performance as closely as possible within limited testing time and operating conditions, while also detecting and identifying potential problems and faults. If conventional vehicle electronic control strategies are used during transmission EOL testing, while the EOL testing and control strategies remain consistent with those of the vehicle, due to the complexity of operating conditions and demanding operating conditions, the EOL testing's detection capabilities are no better than those of the vehicle itself, potentially leading to transmission failures being passed on to customers. When the transmission's main oil gallery becomes clogged, conventional transmission EOL testing, using a vehicle-based strategy and controlling the electric pump speed at a low level, will be unable to detect and identify the blockage, resulting in low detection capabilities. Currently, the most common EOL testing method for oil-cooled hybrid transmissions on the market uses a shared module for both the EOL test and vehicle control strategies. This fails to decouple the electronic oil pump control strategy from the vehicle's operating strategy during the EOL test, making it impossible to independently adjust the electronic oil pump speed during the EOL test to improve the transmission EOL test's ability to detect main oil gallery blockages. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for detecting main oil channel blockage faults during the EOL test of a transmission, so as to solve the problems raised in the background technology. By increasing the speed of the electronic oil pump in the closed pipe state during the EOL test, the problem of main oil channel blockage of the transmission can be effectively identified.

[0004] To achieve the above objectives, the present invention provides the following solution: a method for detecting a main oil channel blockage fault during a transmission EOL test, the specific steps comprising:

[0005] Decoupling the EOL test mode from the vehicle power-on self-test mode on the transmission controller;

[0006] When the transmission controller is powered on, it first performs mode recognition. If it is EOL mode, the controller's control strategy for the transmission in EOL offline test mode is executed; if it is vehicle power-on self-test mode, the controller's control strategy for the transmission in vehicle mode is executed.

[0007] By adopting the above technical solution, the following beneficial technical effects are achieved: the transmission EOL offline test module is decoupled from the vehicle use control module, and the EOL test can realize the liberalized control of the electronic oil pump without affecting the vehicle strategy.

[0008] Preferably, in the EOL test mode, the controller's control strategy for the transmission is subdivided by identifying and distinguishing whether the MCU is open.

[0009] By adopting the above technical solution, the following beneficial technical effects are achieved: the EOL mode distinguishes between the open and closed pipe states. In the open pipe state, the control strategy of the electronic oil pump is consistent with the control strategy of the entire vehicle. In the closed pipe state, the speed of the electronic oil pump can be freely adjusted to achieve the purpose of testing the transmission under various combination conditions and improve the detection capability.

[0010] Preferably, if the MCU is turned on, the controller's control strategy for the transmission electronic oil pump is consistent with the vehicle power-on self-test mode; if the MCU is not turned on, the controller freely adjusts the speed of the electronic oil pump.

[0011] Preferably, when the MCU does not open the pipe, the controller controls the speed of the electronic oil pump to be ≥2500rpm, thereby detecting whether the main oil channel is blocked.

[0012] By adopting the above technical solution, the following beneficial technical effects are achieved: based on the characteristics of internal oil return of the electronic oil pump and the potential problem of abnormally small oil outlet channel, by increasing the speed of the electronic oil pump in EOL mode to ≥2500rpm, the potential problem of main oil channel blockage can be effectively detected.

[0013] Preferably, the conditions for determining whether the MCU is open are: whether the transmission has a torque request, a hill assist torque request, and whether the speed request is greater than a certain value.

[0014] According to a specific embodiment provided by the present invention, the following technical effects are disclosed: In the electronic control software of an oil-cooled hybrid transmission, the EOL (End-of-Life) test module, which controls the transmission strategy, is decoupled from the vehicle operation control module. Furthermore, the EOL test module adds open-pipe and closed-pipe strategies. During the EOL test process, EOL test conditions and parameters can be modified to improve detection capabilities without affecting vehicle operation. By increasing the speed of the electronic oil pump in the closed-pipe state during EOL testing, transmission main oil channel blockage can be effectively identified. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A flow chart of a method of the prior art;

[0017] Figure 2 is a flow chart of the method of the present invention;

[0018] Figure 3 Schematic diagram of a simplified model of a blockage in the oil outlet channel of an electronic oil pump according to the present invention. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] The common EOL test method for oil-cooled hybrid transmissions in the market is to use the same module for the offline test control strategy and the vehicle control strategy. The EOL test process does not decouple the control strategy of the electronic oil pump from the vehicle usage strategy. Figure 1 As shown, the disadvantages of this design are:

[0021] 1. The EOL test software is not decoupled from the vehicle control strategy. Changing the EOL test parameters will affect the vehicle control strategy.

[0022] 2. The EOL test is conducted at room temperature. According to the control strategy, the transmission electronic oil pump has a low speed, with a maximum speed of approximately 1000 rpm to 1500 rpm. At this speed, the electronic oil pump feedback signal cannot distinguish and detect the transmission main oil gallery.

[0023] 3. EOL detection capability is not higher than the vehicle self-inspection capability.

[0024] In order to make up for the defects of the prior art and to have the ability to efficiently detect and identify the blockage problem of the transmission main oil channel, the purpose of the present invention is to provide a method for detecting the blockage fault of the main oil channel in the transmission EOL test, such as Figure 2 As shown, the specific steps include:

[0025] S1. Decouple the EOL test mode from the vehicle power-on self-test mode on the transmission controller;

[0026] S2. When the transmission controller is powered on, it first performs mode recognition. If it is EOL mode, the controller's control strategy for the transmission in EOL offline test mode is executed; if it is vehicle power-on self-test mode, the controller's control strategy for the transmission in vehicle mode is executed.

[0027] Furthermore, in the EOL test mode, the controller's transmission control strategy is further refined by identifying whether the MCU is powered on. If the MCU is powered on, the controller's control strategy for the transmission's electronic oil pump is consistent with the vehicle's power-on self-test mode. If the MCU is powered off, the controller freely adjusts the electronic oil pump's speed.

[0028] MCU open: the electronic control has torque, speed and other requests (consistent with the vehicle power-on self-test mode control);

[0029] The MCU is not open: This means the electronic control output command is 0 or the speed is below a threshold (the production line motor can reverse the transmission to test some customized operating conditions). During EOL testing, the transmission is open and closed. In the open state, the electronic control strategy for the transmission electric pump is consistent with that of the vehicle. In the open state, the electronic control of the electric pump can be customized without affecting the operation of the vehicle.

[0030] like Figure 3 The following diagram shows a simplified model of a blocked oil pump outlet passage. It can be seen that when the main oil passage is blocked or leaking, assuming the electronic oil pump speed is low, such as 1500 rpm (based on a 4.5 cc / rev displacement, the theoretical oil flow rate is 6.75 L / min), air accumulates within the electronic oil pump cavity and oil passages. This air circulates through the cooling and lubrication passages and rotor passages within the electronic oil pump. Although the electronic oil pump's cooling and lubrication passages and rotor teeth and clearances are small, the air resistance is low. Therefore, the air circulation within the cavity does not significantly increase the electronic oil pump's torque, resulting in no abnormal feedback signal. When the electronic oil pump speed is increased to 2500 rpm or higher, the excessive air flow within the cavity prevents the high-pressure air from flowing to the low-pressure area in a timely manner, forming a vacuum in the low-pressure area. Oil successfully enters the cavity, causing a transient increase in the electronic oil pump's torque and abnormal performance (abnormally high current, and the actual speed failing to reach the target speed).

[0031] Therefore, in this embodiment, when the MCU does not open the pipe, the controller controls the speed of the electronic oil pump to be ≥2500 rpm, thereby detecting whether the main oil channel is blocked.

[0032] Furthermore, the conditions for determining whether the MCU is open are: whether the transmission has a torque request, a hill assist torque request, and whether the speed request is greater than a certain value.

[0033] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method for detecting a main oil channel blockage fault during a transmission EOL test, characterized in that: The specific steps include the following: Decoupling the EOL test mode from the vehicle power-on self-test mode on the transmission controller; When the transmission controller is powered on, it first performs mode recognition. If it is EOL mode, it executes the control strategy of the controller for the transmission in EOL offline test mode. If the vehicle is in the power-on self-test mode, the control strategy of the controller for the transmission in the vehicle mode is executed.

2. The method for detecting a main oil channel blockage fault in a transmission EOL test according to claim 1, characterized in that: In the EOL test mode, the controller's control strategy for the transmission is subdivided by identifying and distinguishing whether the MCU is open.

3. The method for detecting a main oil channel blockage fault in a transmission EOL test according to claim 2, characterized in that: If the MCU is open, the controller's control strategy for the transmission electronic oil pump is consistent with the vehicle power-on self-test mode; if the MCU is not open, the controller freely adjusts the speed of the electronic oil pump.

4. The method for detecting a main oil channel blockage fault in a transmission EOL test according to claim 2, characterized in that: When the MCU does not open the pipe, the controller controls the speed of the electronic oil pump to ≥2500rpm, and then detects whether the main oil channel is blocked.

5. The method for detecting a main oil channel blockage fault in a transmission EOL test according to claim 2 is characterized in that: The conditions for judging whether the MCU is turned on are: Check whether the transmission has a torque request, a hill assist torque request, or whether the speed request is greater than a certain value.

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