CN-122016326-A - Fault diagnosis method and device for engine, vehicle and storage medium

CN122016326ACN 122016326 ACN122016326 ACN 122016326ACN-122016326-A

Abstract

The application provides a fault diagnosis method, device, vehicle and storage medium of an engine, wherein the method comprises the steps of controlling the duty ratio of an engine oil control valve of the engine to rise from an initial duty ratio to a target duty ratio under the condition that a phaser of the engine is in a locking state so as to unlock the phaser, adjusting the phase of the unlocked phaser to a target phase, and determining a first difference value between the actual phase of the phaser and the target phase of the phaser after adjustment, wherein the target phase is determined based on the working condition of the engine, and determining a fault diagnosis result of a VVT mechanism in the engine according to a second difference value between the actual phase of the phaser and the locking phase of the phaser under the condition that the absolute value of the first difference value is larger than a first angular threshold value for a first duration, wherein the fault diagnosis result comprises the fault diagnosis result of an unlocking stage and the fault diagnosis result of an adjusting stage.

Inventors

XIE ZONGRANG
LIN HAN

Assignees

重庆长安汽车股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260313

Claims (12)

1. A fault diagnosis method of an engine, characterized by comprising: controlling a duty cycle of an oil control valve of the engine to rise from an initial duty cycle to a target duty cycle to unlock the phaser when the phaser of the engine is in a locked state; adjusting the phase of the unlocked phaser to a target phase, and determining a first difference between the actual phase of the phaser after adjustment and the target phase of the phaser, wherein the target phase is determined based on the operating condition of the engine; And under the condition that the first time length is continuous and the absolute value of the first difference value is larger than a first angle threshold value, determining a fault diagnosis result of a VVT mechanism in the engine according to a second difference value of the actual phase of the phaser and the locking phase of the phaser, wherein the fault diagnosis result comprises a fault diagnosis result of an unlocking stage and a fault diagnosis result of an adjusting stage.
2. The fault diagnosis method according to claim 1, wherein the determining the fault diagnosis result of the VVT mechanism in the engine based on the second difference between the actual phase of the phaser and the lock-up phase of the phaser, comprises: Determining that the fault diagnosis result of the VVT mechanism is the fault diagnosis result of the regulation stage when the absolute value of the second difference is larger than a second angle threshold value, determining the fault diagnosis result of the regulation stage according to the phase change amount in a second time period, or And determining that the fault diagnosis result of the VVT mechanism is the fault diagnosis result of the unlocking stage when the absolute value of the second difference value is smaller than or equal to a second angle threshold value, and determining the fault diagnosis result of the unlocking stage according to the phase change amount in a second time period, wherein the fault diagnosis result comprises a slow fault and a stuck fault.
3. The fault diagnosis method according to claim 2, wherein the determining the fault diagnosis result of the unlocking stage according to the phase change amount in the second period of time includes: Outputting a jamming fault code in the unlocking stage under the condition that the phase change amount in the second time period is smaller than or equal to a third angle threshold value; And outputting the slow fault code in the unlocking stage under the condition that the phase change amount in the second time period is larger than a third angle threshold value.
4. The fault diagnosis method according to claim 2, wherein the determining the fault diagnosis result of the adjustment phase based on the phase change amount in the second period of time includes: Outputting a stuck fault code in the adjusting stage under the condition that the phase change amount in the second time period is smaller than or equal to a third angle threshold value; and outputting the slow fault code in the adjusting stage under the condition that the phase change amount in the second time period is larger than a third angle threshold value.
5. The fault diagnosis method according to any one of claims 1 to 4, characterized in that the method further comprises: And under the condition of outputting the fault code, if the same fault code is output in N continuous driving cycles, a fault lamp of the engine is lightened.
6. The fault diagnosis method according to claim 5, characterized in that the method further comprises: and when the fault lamp of the engine is turned on, if the same fault code is not output in M driving cycles, turning off the fault lamp.
7. The fault diagnosis method according to claim 5, characterized in that the method further comprises: And deleting the fault code under the condition that the fault lamp is turned off and the same fault code is not output by the engine in P continuous warm-up cycles.
8. The fault diagnosis method according to claim 5, wherein in the event that the fault code is a sluggish fault code in the unlock phase or a stuck fault code in the unlock phase, in determining a fault diagnosis result of the VVT mechanism, the duty ratio of the engine oil control valve that controls the engine is raised from the initial duty ratio to the target duty ratio, comprising: And after the duty ratio of the engine oil control valve is controlled to rise from the initial duty ratio to a maintaining duty ratio for a third duration, controlling the duty ratio of the engine oil control valve to rise from the maintaining duty ratio to the target duty ratio, wherein the maintaining duty ratio is used for ensuring that the pressure difference between an advance regulating oil cavity of the phaser and a retard regulating oil cavity of the phaser is consistent.
9. A fault diagnosis apparatus of an engine, characterized by comprising: a control module configured to control a duty cycle of an oil control valve of the engine to rise from an initial duty cycle to a target duty cycle to unlock a phaser of the engine with the phaser in a locked state; The adjusting module is configured to adjust the phase of the unlocked phaser to a target phase and determine a first difference value between the actual phase of the phaser after adjustment and the target phase of the phaser, wherein the target phase is determined based on the working condition of the engine; The determining module is configured to determine a fault diagnosis result of a VVT mechanism in the engine according to a second difference value of an actual phase of the phaser and a locking phase of the phaser when the absolute value of the first difference value is larger than a first angular threshold value and the first time duration is longer than the first angular threshold value, wherein the fault diagnosis result comprises a fault diagnosis result of an unlocking stage and a fault diagnosis result of an adjusting stage.
10. A vehicle characterized in that it comprises an engine, an electronic control unit and a memory, said memory being adapted to store a computer program running on said electronic control unit, said electronic control unit being adapted to execute said computer program in said memory, performing the fault diagnosis method of an engine according to claims 1 to 8.
11. A computer-readable storage medium having stored thereon a computer program, characterized in that the computer program is executed by an electronic control unit by the fault diagnosis method of an engine according to claims 1 to 8.
12. A computer program product comprising a computer program or instructions which, when executed by an electronic control unit, implements the method for diagnosing faults of an engine according to claims 1 to 8.

Description

Fault diagnosis method and device for engine, vehicle and storage medium Technical Field The application relates to the technical field of vehicle control, in particular to a fault diagnosis method and device of an engine, a vehicle and a storage medium. Background The VVT (Variable VALVE TIMING, VVT) is also called Variable valve timing technology, which is used for controlling the cam phase of an engine on the engine to change the opening and closing time of the valve so as to adapt to the requirements of different working conditions of the engine, thereby improving the performance and the fuel economy of the engine and reducing the emission of harmful substances such as hydrocarbon, nitrogen oxide and the like, and is a key technology necessary for the current high-performance engine. The VVT includes a phaser, an oil control valve, and an electromagnet. The working principle of the VVT is that an electronic control unit (Electronic Control Unit, ECU) transmits the duty ratio to the electromagnet, and an engine oil control valve is controlled to switch different oil paths to different oil cavities of a phaser, and the phaser is driven by engine oil pressure to realize the adjustment of the phase of an engine camshaft according to the requirement. Because of the complex working principle of the VVT, the VVT fault always belongs to the after-sale key problems of the engine, but the VVT fault cannot be precisely diagnosed at present. Disclosure of Invention Embodiments of the present application provide a fault diagnosis method for an engine, a fault diagnosis apparatus for an engine, a vehicle, a computer-readable storage medium, and a computer program product, which are useful for subdividing fault types of a VVT mechanism, thereby accurately guiding after-sales maintenance, improving maintenance efficiency, and reducing maintenance costs. In a first aspect, an embodiment of the application provides a fault diagnosis method of an engine, which comprises the steps of controlling a duty ratio of an engine oil control valve of the engine to rise from an initial duty ratio to a target duty ratio under the condition that a phaser of the engine is in a locked state so as to unlock the phaser, adjusting the phase of the unlocked phaser to a target phase, and determining a first difference value between an actual phase of the phaser and the target phase of the phaser after adjustment, wherein the target phase is determined based on working conditions of the engine, and determining a fault diagnosis result of a VVT mechanism in the engine according to a second difference value between the actual phase of the phaser and the locked phase of the phaser under the condition that the absolute value of the first difference value is larger than a first angle threshold for a first duration, wherein the fault diagnosis result comprises a fault diagnosis result of an unlocking stage and a fault diagnosis result of an adjusting stage. It can be appreciated that in the fault diagnosis method provided by the embodiment of the application, when the phaser of the engine is in a locked state, the lock pin of the phaser is unlocked by controlling the duty ratio of the engine oil control valve to rise from the initial duty ratio to the target duty ratio, then the phase of the unlocked phaser is adjusted to the target phase, and the first difference between the actual phase of the adjusted phaser and the target phase is determined. And then determining that the fault diagnosis result of the VVT mechanism in the engine is the fault diagnosis result of the unlocking stage or the fault diagnosis result of the regulating stage according to the second difference value of the actual phase and the locking phase of the phaser. Thus, the fault type of the VVT mechanism is subdivided, so that after-sale maintenance is guided accurately, the maintenance efficiency is improved, and the maintenance cost is reduced. In some embodiments, the determining a fault diagnosis result of the VVT mechanism in the engine according to a second difference value between the actual phase of the phaser and the lock-up phase of the phaser includes determining that the fault diagnosis result of the VVT mechanism is a fault diagnosis result of an adjustment phase if an absolute value of the second difference value is greater than a second angle threshold value, determining that the fault diagnosis result of the adjustment phase is a fault diagnosis result of an unlock phase if an absolute value of the second difference value is less than or equal to the second angle threshold value according to a phase change amount within a second period of time, and determining that the fault diagnosis result of the unlock phase is a fault diagnosis result according to a phase change amount within a second period of time, wherein the fault diagnosis result includes a slow fault and a stuck fault. It can be understood that in the fault diagnosis method provided by the embodiment o