DE102006032910A1 - Mechanical units evaluating method for motor vehicle, involves coupling solid borne sound sensor signal at predetermined position in and/or at motor vehicle, and measuring signals that are arriving at vehicle in another position - Google Patents

Abstract

The method involves arranging an acceleration and/or solid borne sound sensor in a motor vehicle (1), where signals that are measured by the sensor are evaluated and compared with reference values. A predetermined broadband acceleration and/or solid borne sound sensor signal is coupled at a predetermined position in and/or at the vehicle, and signals that are arriving at the vehicle are measured at another spaced position. The sensor signals are transferred via mechanical units. An independent claim is also included for a portable evaluation system for implementing a method for evaluation of mechanical units in a motor vehicle.

Description

The The invention relates to a method for evaluating mechanical elements in a motor vehicle.

in the Development and production process become mechanical elements in a motor vehicle subjected to a series of stress tests, for stability of the motor vehicle.

To the delivery of the vehicle to the customer, but it comes through Aging, weathering, accidents and repairs to one change the mechanical elements. Although are by visual inspection and technical specifications for fastening and repair measures a number of shortcomings detectable, but are still not visually imperceptible defects excluded. Especially the mechanical stability of load-bearing elements, not exchanged after an accident, but by bending in the original position is reformed have been difficult to evaluate.

at Today's accelerometers are used to prove the functionality of the same, usually during commissioning (Power On / ignition key passive ➜ active) checked by an initiated test phase, whether the accelerometer, on a test stimulation at a designated entrance, on Output shows / generates a corresponding expected signal to Due its shape and amplitude to the correct functionality, in particular the amplification factor and filter characteristics of being able to close the acceleration sensor. Furthermore it is known, based on the vibrations occurring during normal driving to recognize whether an acceleration or structure-borne noise sensor is still intact is.

These Tests are limited only to the electrical functionality of the sensor, as well as the signal chain from the sensor to the evaluation unit.

Not considered In contrast, in these current tests, the mechanical signal transmission path, So if, for example, the mechanical support still the original Has rigidity.

The Object of the present invention is therefore, a suitable Method for evaluating mechanical elements in a motor vehicle present

These The object is solved by the features of the independent claims. advantageous Developments of the invention will become apparent from the dependent claims, wherein also combinations and developments of individual features with each other are conceivable.

One essential idea of the invention is that the properties mechanical elements forward acceleration or structure-borne noise signals, quite significant for the rating of these mechanical elements is. Therefore it is suggested while the lifetime of the vehicle at least temporarily limited to the implementation of the Method at least one acceleration and / or structure-borne sound sensor to arrange in the vehicle and the signals detected by this to evaluate and compare with setpoints. Preferably of course sensors already used to trigger occupant protection equipment or to detect knocking combustion in the vehicle are.

Of the particular advantage of this test is that, in particular, not synonymous visible changes inaccessible Spots or detected in the material substance of the mechanical elements become. Are imitations instead of prescribed replacement parts This can also be used with other material properties be recognized.

Preferably is at least one predetermined position in or on the motor vehicle a predetermined acceleration and / or structure-borne noise signal coupled and at least one other, spaced position there recorded incoming signals. The more measurements are taken, the more mechanical elements of the vehicle can be rated. A Such coupling can be temporarily fixed for the test on the vehicle or permanently arranged in the vehicle signal generator, for example. An electric controllable clapper or the like. Advantage of this artificial Suggestion is the particularly well-defined characteristics of the coupled Signal.

Preferably becomes a broadband structure-borne sound signal coupled and analyzed, with what strength at least certain frequency ranges this broadband structure-borne sound signal over the transmitted mechanical elements become.

The Evaluation is preferably done with the vehicle stationary and stationary Drive motor, for example, after the commissioning of the vehicle electrical system before the start, since then largely excluded interference can be and the amplitude of the injected signal correspondingly low chosen can be.

Alternatively, the strength of the natural noise and / or the normal vehicle vibrations, for example the vibrations when the engine is on drive motor and stationary vehicle or the normal vibration from the road.

Preferably is a motor vehicle with at least one acceleration and / or Acoustic emission sensor to carry out the method with at least one acceleration and / or structure-borne sound generator at least one predetermined position for generating the predetermined Signal equipped. That offers the possibility of mechanical Evaluate elements cyclically during normal operation of the vehicle and with no longer tolerable deviations from the default values the driver to give a warning and to ask him to visit a workshop.

Want for example, for cost reasons the vehicles are not permanently equipped with such a signal generator, is besides the use of other signal sources, such as the noise or the normal vehicle vibrations also the use of mobile rating systems conceivable, for example, in the workshops used to evaluate the mechanical elements.

One such mobile rating system has, for example, a mobile and evaluation unit and at least one mobile acceleration and / or Body sound generator for the Generation of the predetermined signal. The signal generator is over one Signal connection connected to the mobile control and evaluation unit, For example, also wirelessly via radio or infrared interface, wherein the Signal generator over Fastening means at least for the implementation the method on a motor vehicle at least one predetermined Position is fastened. By means of a readout unit will be on the at least one sensor read out the detected signal components and pass it on to the control and evaluation unit. The readout unit can for example, be plugged into a connector interface of the sensor, activate and energize the sensor and the sensor incoming signals transmitted to the control and evaluation.

alternative could the readout unit can be connected to a vehicle data bus and over the vehicle data bus to be connected to the sensor.

It So is at least one point in / on the vehicle, which, for example a typical location corresponds to this in a crash acceleration forces on act on the vehicle, mounted an electrically controllable actuator, which for Can be activated for test purposes so that it is in test mode, For example, at each startup of the motor vehicle or the Self-diagnosis of vehicle electronics, a defined force pulse on the vehicle structure, which by means of evaluation of the (-Borne) frequency spectrum is evaluated by the sensor assembly by comparing this Spectrum is performed with a predetermined expected spectrum.

Provided when comparing the spectrum received during the test with the given one to the expected spectrum within given tolerances, will the review as rated error-free, whereas at a significant deviation of the received spectrum with the given expected spectrum an error is detected, or this in a non-volatile memory is deposited and brought to the display.

The Invention will now be described below with reference to an embodiment with the aid closer to the figures explained. In the following you can functionally identical and / or identical elements with the same reference numerals be designated. Show it

1 Example, in which by means of an actuator, a force pulse is applied to a typical Crashrelevanten spot on the vehicle.

Like from the 1 is apparent, for example, in the front area of the vehicle ( 1 ) an actor ( 3 ), which in this example is designed as a lifting magnet and whose movable armature can apply a force impulse to the vehicle structure when the actuator ( 3 ) by means of a control signal ( 3.1 ) from the ECU ( 2.1 ) is controlled accordingly. Due to the applied to the vehicle structure / embossed force impulse arises in the vehicle structure, a frequency spectrum ( 3.2 ) which propagates within the vehicle structure / vehicle body (shown only one direction of propagation). By means of the centrally located in the vehicle acceleration sensor assembly, here also as an ECU (Electronic Central Unit) ( 2.1 ), the frequency spectrum generated on a test pulse ( 3.2 Received and evaluated, the evaluation includes both the frequency components and the signal amplitudes to perform the assessment of the quality of the signal transmission path can.

As can be further seen from the figure, the sensor assembly, instead of in the ECU ( 2.1 ) as an independent unit as an outsourced satellite ( 2.2 ), whose output signals (not shown) of a control unit, such as the ECU ( 2.1 ).

The advantage that can be achieved with the method or device compared with the prior art is a review or assessment of the mechanical elements and thus of the installation site / signal transmission to the installation location via the drive tool lifetime and thus a signal corruption by vehicle structure changes can be excluded, so that due to the very high achievable reliability in a vehicle crash, the trigger-relevant algorithm decisions can be based primarily or exclusively on acceleration or structure-borne sound signal components, resulting in very fast Tripping times can be guaranteed, and a waiver of outsourced assistance satellites is possible.

In conclusion, be pointed out that in the course of the application under the term "sensor assembly" a signal acquisition system is to be understood, which has at least one sensor element, which can detect accelerations and / or body sound signals.

When alternative solution, to the methods described above or the presented device it is also possible to evaluate a place of installation in such a way that instead of an actuator in the vehicle for suggestion, such an expiring review in the customer service work to be carried out at each scheduled workshop visit, to be included.

The review is to do this in such a way that at predetermined points on the vehicle by the workshop staff Actuator is placed on the vehicle structure and a corresponding force pulse is introduced into the vehicle structure, wherein the arriving at the control unit Frequency spectrum correspond as described above, with a too expected frequency spectrum is compared.

Claims (10)

Method for evaluating mechanical elements in a motor vehicle, wherein at least one acceleration and / or Acoustic emission sensor is arranged in the motor vehicle and the signals detected by this evaluated and compared with setpoints. The method of claim 1, wherein at least one predetermined position in or on the motor vehicle a predetermined Acceleration and / or structure-borne sound signal coupled and at at least one other, spaced position the signals arriving there are detected. The method of claim 2, wherein a broadband Borne noise signal is coupled and analyzed, with what strength at least certain frequency ranges of this broadband structure-borne sound signal over the transmitted mechanical elements become. Method according to one of the preceding claims, wherein for the Evaluation a structure-borne noise sensor already present in the vehicle is used, in particular a structure-borne sound sensor for crash detection or detecting knocking combustion during normal operation of the vehicle. Method according to one of the preceding claims, wherein the evaluation with stationary vehicle and stationary drive motor he follows. Method according to one of the preceding claims, wherein at one for the impact of bumps in an accident typical place an electrically controllable signal generator is attached and on a command out a defined force pulse generated and on a sensor provided centrally in the vehicle incoming signals is detected and evaluated, whether the signal forwarding not disturbed to the sensor is. The method of claim 1, wherein the strength of the natural Noise and / or normal vehicle vibration. Mobile rating system for the implementation of the Method according to one of the preceding claims, consisting of - one mobile control and evaluation unit, - at least one acceleration and / or body sound generator for the Generation of the predetermined signal with a signal connection to mobile control and evaluation unit, wherein the signal generator via fastening means at least for the implementation the method on a motor vehicle at least one predetermined Position in operative connection can be brought - a readout unit for Reading out the signal components detected on at least one sensor and for passing on to the control and evaluation unit. A mobile rating system according to claim 8, wherein said Readout unit attachable to a connector interface of the sensor is the sensor activated and energized and the sensor incoming signals transmitted to the control and evaluation. Mobile rating system according to claim 8 or 9, wherein the read-out unit can be connected to a vehicle data bus is and about the vehicle data bus activates the sensor and the sensor arriving at the sensor Signals transmitted to the control and evaluation.