Method and device for diagnosing functionality of active engine mount
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-04-26
- Publication Date
- 2026-04-07
AI Technical Summary
Existing methods for monitoring the functionality of active engine mounts in vehicles are inadequate in effectively detecting and addressing vibrations that affect emission and safety functions, particularly due to crosstalk with rotational speed signals.
A method involving bandpass filtering of rotational speed signals to identify specific frequency ranges, analyzing vibration energy and amplitude, and comparing against thresholds to determine errors in active mounts, with error responses such as notifications or adjustments.
Effectively monitors and responds to errors in active mounts, ensuring reduced vibrations and improved emission and safety performance by actively damping vibrations.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an active mount system for a prime mover with large vibrations, particularly for an internal combustion engine, and more particularly to a method for detecting or diagnosing the functionality of an active engine mount.
Background Art
[0002] For example, an active engine mount is usually used to reduce the vibration of a prime mover such as an internal combustion engine from disturbing the surrounding systems of, for example, an automobile. The active engine mount is disposed between a holding frame and the prime mover, and by appropriately canceling and compensating the excitation in a specific frequency range by the prime mover, the vibration transmission to the frame on which the prime mover is held is significantly reduced. Alternatively, the active engine mount may have controllable variable damping that can be adjusted according to the vibration excitation of the prime mover.
[0003] Within the scope of legal requirements, it is necessary to monitor all emission-related functions and safety-related functions in an automobile. In particular, since the vibration excitation by the prime mover may cross-talk with the rotational speed signal measured there, and thus may affect the exhaust gas emission or emission reduction function in an internal combustion engine as a prime mover, it is necessary to monitor the functionality of the active engine mount that attenuates such excitation.
[0004] German Patent Application Publication No. 102018107732 discloses a method and system for diagnosing whether an active engine mount, configured to isolate engine vibrations from the vehicle cabin and chassis, is functioning as intended. In one example, the method includes inducing a combustion event disruption in a pre-selected engine cylinder and activating the active engine mount in multiple modes to indicate the disruption of the active engine mount, the indication of which is in response to the amount of vibration of the vehicle chassis in each mode. By monitoring the chassis vibration in response to the induced combustion event disruption and in response to the active engine mount being controlled in multiple modes, it is possible to indicate whether the active engine mount is functioning as intended.
[0005] German Patent Application Publication No. 102006044320 discloses an active mount for attaching a drive unit to a vehicle support frame, comprising at least one elastic passive mount member, at least one actuator, a sensor for measuring vibrations of the drive unit, and a control device associated with the actuator for processing measurement signals from the sensor and controlling the actuator so that vibrations generated from the drive unit are actively attenuated and / or frequency-shifted within the mount system. The mount can be used not only to actively cancel vibrations generated during the operation of the drive unit, but is also suitable for providing diagnostic functions to the drive unit via the sensor system required for the active mount system, for timely detection of abnormal vibrations caused by wear of parts, and for taking appropriate countermeasures. [Prior art documents] [Patent Documents]
[0006] [Patent Document 1] German Patent Application Publication No. 102018107732 [Patent Document 2] German Patent Application Publication No. 102006044320 Specification [Overview of the Initiative] [Means for solving the problem]
[0007] According to the present invention, a method for monitoring the function of an active mount for mounting a prime mover according to claim 1, and a corresponding device according to an independent claim are envisioned. The improved form is described in the cited claim.
[0008] According to the first aspect, a method for testing the functionality of an active mount system for a prime mover, - A step of operating an engine system, which includes an active mount system configured to eliminate or reduce vibrations generated by the operation of the engine system, - A step of providing a display of the engine speed, - The step of filtering the RPM display waveform with a bandpass filter within at least one pass-through frequency domain, -A step of analyzing the waveform of the rotational speed representation within at least one pass-through frequency range to determine the vibration energy or maximum amplitude, - A step of determining the error according to the vibration energy or maximum amplitude, A method including this is being considered.
[0009] In automotive engines, particularly internal combustion engines, vibrations from and to the engine are damped by an active mount system having one or more active mounts. Here, the vibration amplitude of the engine vibration is measured, and the vibration is damped by the active control of one or more active mounts.
[0010] Engine vibrations affect the rotational speed waveform. For the control of other engine functions, the rotational signal is usually already detected in the engine, and this can be appropriately evaluated to detect engine vibrations.
[0011] In addition, the above method is intended to detect the rotational speed signal over a specific time range and evaluate it with respect to one or more predetermined frequency ranges using frequency analysis. Here, one or more frequency ranges are selected as known frequency ranges in which excitation occurs due to the operation of the prime mover, for example, by resonance.
[0012] Furthermore, at least one pass-frequency region can be determined, in particular using a characteristic map, depending on the operating point of the prime mover, defined by the load and / or rotational speed. Additionally, the gain and / or edge slope of the bandpass filter for each of the at least one pass-frequency regions can be determined, in particular using a characteristic map, depending on the operating point of the prime mover, defined by the load and / or rotational speed.
[0013] The characteristic map can be configured to display at least one pass-frequency range such that the excitation generated by the operation of the prime mover is attenuated by the vibration suppression function of the active engine mount.
[0014] The rotational speed signal can be filtered using a bandpass filter, and one or more predetermined frequency regions (passbands) of the bandpass filter are selected such that the excitations generated therein are attenuated by the function of the active engine mounts. Here, the passbands are selected such that the excitations compensated or attenuated by the active mount system are particularly prominent in the resulting signal. In particular, the passbands may include one or more resonant frequencies of the engine system.
[0015] Error detection can be performed by comparing the vibration energy or maximum amplitude with a threshold value. In particular, the threshold value can be selected according to the operating point of the prime mover.
[0016] The filtered rotational speed signal is evaluated by comparing the respective vibration energy or maximum amplitude of one or more frequency ranges with a predetermined, fixed or variable threshold value. If the identified vibration energy or maximum amplitude exceeds the threshold value in at least one of the one or more frequency ranges, an error response can be executed.
[0017] The characteristics of the band-pass filter and the threshold value used for the threshold comparison of the vibration energy can be set according to the operating point using, for example, a characteristic map. In addition, the operating point of the prime mover can be determined by, for example, the load and the rotational speed.
[0018] The error response can, for example, perform an error input to an error memory, a service notification to the driver of a motor vehicle, an online report to a fleet management system, a repetition of measurements for validation, and / or the implementation of an emergency operation, particularly by reducing the engine torque of the prime mover.
[0019] According to a further aspect, a prime mover, an active mount system for reducing vibration excitation on a holding part due to the operation of the prime mover, - operating an engine system comprising an active mount system configured to eliminate or reduce the generation of vibrations due to the operation of the engine system, - providing a rotational speed display of the prime mover, - filtering the waveform of the rotational speed display with a band-pass filter within at least one pass frequency range, - analyzing the waveform of the rotational speed display within at least one pass frequency range to determine the vibration energy or maximum amplitude, - determining an error according to the vibration energy or maximum amplitude, A device comprising a mount control unit configured as described above is contemplated.
Brief Description of the Drawings
[0020] Embodiments will be described in detail below with reference to the accompanying drawings. [Figure 1]It is a schematic diagram of a prime mover for an automobile, which is suspended from the frame of the automobile by an active mount system. [Figure 2] It is a flowchart for explaining a method for inspecting the functionality of an active mount system. [Figure 3] It is a diagram of frequency and vibration energy regarding vibration energy levels in different frequency bands at an operating point of the prime mover.
Mode for Carrying Out the Invention
[0021] FIG. 1 schematically shows a part of an engine system of an automobile including a prime mover 1 suspended from a frame 2 of the automobile. The prime mover 1 functions to drive the automobile and can be configured as an internal combustion engine or the like, and particularly can be configured as a prime mover that may cause different vibrations according to the operating point during operation.
[0022] The prime mover 1 is connected to the drive train of the automobile via an output shaft 3. A rotational speed sensor 4 capable of detecting a rotational speed signal with high time resolution is arranged on the output shaft 3. The prime mover 1 is suspended from the frame via an active mount system including one or more active mounts 5. The active mount system is intended to adjust damping stepwise or variably according to a mount control signal L and / or variably apply cancellation at one or more specific frequencies. The mount control signal L is provided by a mount control unit 6.
[0023] The mount control unit 6 can be implemented by a microcontroller and is configured to execute control of the active mount based on a characteristic map according to the operating point of the prime mover 1 or based on measurement of the actually generated vibration of the prime mover 1. The actually generated vibration of the prime mover 1 can be detected by sensors or other methods.
[0024] To test the functionality of the active mount 5, the mount control unit 6 or a further control unit is provided with a function used to monitor the proper functioning of the active mount system.
[0025] This method can be implemented in hardware and / or software in the mount control unit 6 and is described in detail with reference to the flowchart in Figure 2. In step S1, it is checked whether the prime mover 1 is operating at an appropriate characteristic map point. The characteristic map point is determined by an operating point that can be characterized not only by instantaneous load and instantaneous rotational speed, but also by other switching conditions.
[0026] If it is determined that the prime mover is at an operating point belonging to a suitable set of characteristic map points (option: yes), the method proceeds to step S2; otherwise (option: no), it returns to step S1. A suitable characteristic map point is considered to be an operating point where excitation occurs, which could lead to vibration of prime mover 1 in the absence of an active mount system. These characteristic map points can be determined by system knowledge or experimentally and set as appropriate.
[0027] In step S2, a rotational speed signal from the rotational speed sensor 4, sampled at a high frequency over a predetermined evaluation time window, is provided. The sampling frequency is preferably 5 kHz or higher, and preferably 10 kHz or higher, in order to enable sufficiently accurate frequency analysis. The rotational speed signal is typically present in the engine system and needs to be provided for evaluation to monitor the functionality of the active mount 5 for the functions described later.
[0028] In step S3, the rotational speed signal, which normally exists as a sampled, i.e., digitized time series, is noise-corrected. For example, outliers are removed and / or the rotational speed signal is smoothed.
[0029] In step S4, the sampled signal time series is filtered by a bandpass filter having one or more pass frequency domains. The gain, edge slope, and pass frequency domain (pass region) of the bandpass filter as filter parameters can be selected according to the operating state according to a predetermined characteristic map. The characteristic map can further take into account, for example, the opening and closing of the clutch and the presence or absence of friction coupling of the transmission.
[0030] The pass-through frequency domain of the bandpass filter is selected such that the excitation compensated by the active mount 5 is particularly prominent in the resulting signal. In step S5, frequency analysis is used to determine the vibrational energy or maximum amplitude for each pass-frequency domain of the filtered signal time series.
[0031] In step S6, the vibration energy or maximum amplitude, or an equivalent quantity, is evaluated for each of the frequency domains by threshold comparison based on predetermined thresholds.
[0032] If, during the inspection in step S7, it is determined that the vibrational energy of the resulting filtered signal time series exceeds a threshold in the pass-through frequency domain (option: yes), then it is determined that an error has occurred in the functionality of the active mount 5.
[0033] The threshold can be fixed or variable, particularly with respect to the gain, edge slope, and pass filter frequency of the bandpass filter. The threshold may be selected according to the filter parameters and also according to the operating point. Alternatively, the threshold may be set by indicating the oscillation energy or maximum amplitude of a second signal with different filtering.
[0034] If an error is determined to have occurred (option: yes), an active response is requested in step S8, and / or the evaluation of whether there is an error in the active mount can be repeated. Furthermore, a corresponding error input, a service notification to the driver, or an online report to fleet management can be triggered. Otherwise (option: no), the process returns to step S1.
[0035] For example, the frequency diagram in Figure 3 shows the curve FL of vibration energy E using the active mount system without errors, the curve FF of vibration energy E using the active mount system with errors, and the threshold level S. The passband of the bandpass filter is indicated as FB.
[0036] By periodically repeating this method, continuous monitoring of the functionality of the active mount system can be reliably achieved.
Claims
1. A method for testing the functionality of an active mount system for a prime mover (1), - A step of operating an engine system, which includes an active mount system configured to eliminate or reduce vibrations generated by the operation of the engine system, - Step (S2) of providing a rotational speed display for the prime mover (1), - Step (S4) of filtering the waveform of the rotational speed display with a bandpass filter within at least one pass-through frequency range (FB), - Step (S5) of analyzing the waveform of the rotational speed display within the at least one pass-through frequency range (FB) to determine the vibration energy or maximum amplitude, - A step (S6, S7, S8) to determine an error according to the vibration energy or the maximum amplitude, A method that includes this.
2. The method according to claim 1, wherein the at least one pass-through frequency region (FB) is determined according to the operating point of the prime mover (1) defined by the load and / or rotational speed.
3. The method according to claim 2, wherein the at least one pass-through frequency region (FB) is determined using a predetermined characteristic map depending on the operating point of the prime mover (1) defined by the load and / or the rotational speed.
4. The method according to claim 1, wherein the gain and / or edge slope of the bandpass filter for each of the at least one pass frequency region (FB) is determined according to the operating point of the prime mover, defined by the load and / or rotational speed.
5. The method according to claim 4, wherein the gain and / or edge slope of the bandpass filter for each of the at least one pass frequency region (FB) is determined using a predetermined characteristic map depending on the operating point of the prime mover defined by the load and / or the rotational speed.
6. The method according to claim 3 or 5, wherein the characteristic map is configured such that the at least one pass-frequency range (FB) is determined such that the excitation generated thereby by the operation of the prime mover (1) is attenuated by the vibration suppression function of the active mount system.
7. The method according to claim 1, wherein the error is determined by performing a threshold comparison with the vibration energy or the maximum amplitude based on the threshold.
8. The method according to claim 7, wherein the threshold is selected according to the operating point of the prime mover (1) defined by the load and / or rotational speed.
9. The method according to claim 1, wherein if an error is detected, an error is entered into an error memory, a service notification is sent to the vehicle driver, an online report is sent to the fleet management system, measurements are repeated for validation, and / or emergency actions are taken.
10. The method according to claim 9, wherein if an error is detected, the engine torque of the prime mover is reduced.
11. The method according to claim 1, wherein the active mount system has counteracting and controllable variable damping.
12. A prime mover (1), and an active mount system that reduces vibration excitation to the holding part caused by the operation of the prime mover, - An active mount system configured to eliminate or reduce vibrations caused by the operation of the engine system, - Provides a rotational speed display for the prime mover (1), - The waveform of the rotational speed display is filtered by a bandpass filter within at least one pass-through frequency range (FB), - Analyze the waveform of the rotational speed indicator within the at least one pass-through frequency range (FB) to determine the vibration energy or maximum amplitude. - Determine the error according to the vibration energy or the maximum amplitude. A mount control unit (6) is configured as follows, A device equipped with.
13. A computer program that, when executed by at least one data processing device, includes an instruction causing the data processing device to perform a step of the method according to any one of claims 1 to 11.
14. A machine-readable storage medium comprising, when executed by at least one data processing device, an instruction causing the data processing device to perform a step of the method according to any one of claims 1 to 11.