GB2567431A

GB2567431A - Method of diagnosing failure in an electronic control unit

Info

Publication number: GB2567431A
Application number: GB1716541.6A
Authority: GB
Inventors: Maftei Alexandru; Rudac Mihaela
Original assignee: Continental Automotive Romania SRL
Current assignee: Continental Automotive Romania SRL
Priority date: 2017-10-10
Filing date: 2017-10-10
Publication date: 2019-04-17
Anticipated expiration: 2037-10-10
Also published as: GB201716541D0; GB2567431B

Abstract

The method diagnoses failure in an electronic control unit 2. The electronic control unit 2 operates as part of a brake module 1 and contains mechanical components 3, 5, and at least an integrated sensor 7 able to detect vibration. The method includes the following steps: memorizing a normal vibration pattern provided by at least one mechanical component that moves inside the electronic control unit 2 in normal working condition; then, at every wake-up of the electronic control unit 2, reading the individual vibration pattern given out by any of the mechanical components that move inside the electronic control unit 2; comparing the memorized vibration pattern with the read vibration pattern for each mechanical component 3, 5, and evaluating the differences between the memorized vibration pattern and the read vibration pattern against predefined thresholds; and initiating an appropriate action, according to the situation.

Description

Method of diagnosing failure in an electronic control unit

The present invention generally relates to diagnosing failure in an electronic control unit and more particularly relates to associated method and computer program. The electronic control unit can be a part of an anti-locking brake system module.

Anti-locking Brake System (ABS) has been designed to maintain vehicle control, directional stability and optimum deceleration under severe braking conditions on most road surfaces, and has become a standard equipment not only for cars, but also for motorcycles or bicycles. The basic components of such a system are several valves, a pump, a low-pressure accumulator, an electric motor and a control module. Wheel speed is monitored by conventional wheel speed sensors, which generate a signal whose amplitude and frequency is proportional to the rotational speed of the wheel. The control module looks for a difference in wheel speed when braking, and initiates ABS braking if one or more wheels are decelerating at a faster pace than other(s), thus preventing the wheels from locking up. As a particular mention, when the ignition is on, the ABS control unit receives a wake-up call and illuminates the warning lamps for a few seconds, in order to check them. It also checks continuity with all wheel speed sensors, as well as its own internal software. If any problems are detected, a fault code is stored in a memory and the system is disabled.

Anyway, the basic ABS concept had been enhanced by adding functions such as Electronic Stability Control or Program (ESC or ESP) . The dynamic stability of a vehicle is essentially maintained and controlled during turning. While experienced drivers know how to steer the vehicle at the right speed during turns depending on the perceived wheel grip on the surface, there are also cases when any of the wheels may skid sideways leading to the vehicle turning more or less than the level of turning the driver intends. In such cases the vehicle tends to spin around its vertical axis, thus losing the correct path. If over-steer or under-steer is not sensed by the driver in time and corrected quickly, the vehicle can create a potential accident situation.

Electronic stability control (ESC) senses the level of loss of control of steering/turning by means of essentially two sensors: yaw rate sensor (gyroscope) which senses the rotation of the vehicle around its vertical axis, and lateral acceleration sensor (accelerometer), which senses if the vehicle undergoes a lateral centrifugal force during cornering or turning. Usually the two sensors come in a single package, build as micro-electro-mechanical systems (MEMS) . Such a device is known as a combo-sensor, and can be integrated on a printed circuit board as a separate ESC electronic control unit, being able to provide inertial inputs to the electronic stability control system.

Monitoring the plurality of sensors detecting the electronic driving stability program for vehicles is disclosed, for example, by the European patent EP1152933B1, belonging to Continental Teves. According to the claimed method, a variety of sensors are monitored by comparing and testing variations in view of their plausibility which is determined by the dependencies of the sensor output signals, followed by producing an error message in the absence of plausibility. The variety of sensors comprises a yaw rate sensor, a transverse acceleration sensor, and a steering angle sensor. Anyway, in an emergency, it is vital that all components of the brake system function with absolute reliability - not only the sensors involved.

For this reason, there is a constant need to find safety options to guarantee the reliable function of all components of such a system. The most important safety options are self-test of the electronic control unit, along with peripheral test of the connected assemblies, including a diagnosis from mechanical point of view of the working components .

Amain object of the present invention is to diagnose failure in an electronic control unit, able to permit an increased reliability and an improved operational safety.

According to the invention, this obj ect is achieved by the subj ect matters of the independent claims, namely a method of diagnosing failure in an electronic control unit, as well as an associated computer program.

Further advantageous embodiments are the subject matter of the dependent claims.

A first aspect of the present invention is a method of failure diagnosing in an electronic control unit, comprising the steps of :

- memorizing a normal vibration pattern provided by at least one mechanical component that move inside the electronic control unit, in normal working condition; then, at every wake-up of the electronic control unit, performing a self-test by

- reading the individual vibration pattern given out by any of the mechanical components that move inside the electronic control unit;

- comparing the memorized vibration pattern with the read vibration pattern for each mechanical component and evaluating the differences between the memorized vibration pattern and the read vibration pattern against predefined thresholds; and

- initiating appropriate actions, according to the situation.

The main advantage of this method is that does not require additional external hardware or physical components to perform such a diagnosis, actually it uses mechanical vibrations generated by the moving mechanical components as an additional self-diagnosis information.

A second aspect of this invention is a computer program that integrates as code lines the mentioned method of failure diagnosing .

The advantage of using such a computer program is that the electronic control unit does not need but an adaptation of a current computer program, not another reprogramming.

In an expedient embodiment of the method according to the invention, if the differences between the memorized vibration pattern and the read vibration pattern are exceeding a first predefined threshold, the electronic control unit sends a warning signal. Similarly, if the differences between the memorized vibration pattern and the read vibration pattern are exceeding a second predefined threshold imposing a safety risk, electronic control unit initiates the complete shut-off of the brake module. This is particularly advantageous since the degree of wear/damage concerning the mechanical components is practically evaluated at every wake-up of the vehicle.

In another favorable embodiment, the mechanical components are individually checked, namely the electric motor, the hydraulic valves and/or the brake pump.

In yet more favorable embodiment, safety thresholds are separately predefined for each mechanical component, so it is possible to know the comparative degree of wear/damage of the respective mechanical component.

Further special features and advantages of the present invention can be taken from the following description of advantageous embodiments by way of the accompanying drawings.

Fig. 1 is a schematic block diagram of an anti-locking brake system module, equipped with an electronic control unit and a combo-sensor .

Fig. 2 is a schematic block diagram of an arrangement of valves inside the electronic control unit from Fig. 1.

Fig. 3 is an example of a normal vibration pattern of acceleration load to bump as a function of frequency, read for a mechanical component in normal working condition.

Fig. 4 is an example of a vibration pattern of acceleration load to bump, read for a worn-out or damaged mechanical component.

Fig. 5 is a flow chart which shows a preferred embodiment of a method according to the invention.

Referring now to Fig. 1, a schematic view of an anti-locking brake system (ABS) module 1 is shown, having as main components an electronic control unit (ECU) 2, an electric motor 3 and a valve block 4. Within valve block 4 is placed a plurality of valves 5. Electronic control unit 2 comprises a corresponding number of valve coils 6 and a combo-sensor 7 mounted together on a printed-circuit board 8, to which electronic components 9 are also soldered.

FIG. 2 shows a schematic view of an arrangement inside the electronic control unit 2, which is a tight box in which all the components are very well fixed together, namely valves 5 electric motor 3 flanged to it, placed in the immediate proximity of combo-sensor 7. During working conditions, the only moving components inside are electric motor 3 and valves 5.

Combo-sensor 7 is a multiple-sensor device integrating accelerometers and gyroscopes into a single package, providing inertial inputs to the electronic stability control (ESC) system. Such a combo-sensor can have, for example, a sensing range of ±12g in dual or tri-axis vibration, while the brake applications with anti-locking brake system and electronic stability control system need up to 4g measuring. Due to the high sensitivity of the combo-sensor 7, and to the fact that the components inside the electronic control unit 2 are tightly held together, the combo-sensor 7 is able to sense every time when electric motor 3 or a valve 5 (mechanical components) are activated. Other mechanical components could be also checked for correct working, for example in the case the anti-locking brake system module 1 is integrated in a brake pump, the respective pump can also be subject to diagnosing. However, instead of perceiving the influence of such vibrations as dangerous, the method according to the invention integrates them as additional information about the status of mechanical components.

In order to be able to do that, electronic control unit 2 is set to memorize a set of predefined normal vibration patterns (which looks like in the example shown by Fig. 3), corresponding to normal working condition, for all the mechanical components, and to compare them with a set of vibration patterns read at every wake-up. An example of how an abnormal vibration pattern looks like is illustrated by Fig. 4.

Fig. 5 illustrates the flow chart of a preferred embodiment of the method according to the invention.

The method of diagnosing failure in an electronic unit comprises the following steps:

- memorize a normal vibration pattern provided by at least one mechanical component (for example, electric motor 3 or valve 5) that move inside an electronic control unit 2, in normal working condition;

- read the individual vibration pattern given out by any of the mechanical components that move inside the electronic control unit 2;

- at every wake-up of the electronic control unit 2, compare the memorized vibration pattern with the read vibration pattern for each mechanical component;

- evaluate the differences between the memorized vibration pattern and the read vibration pattern against predefined thresholds, and initiate action according to the situation.

The last step has the following sub-steps:

S4 .1 - if the differences between the memorized vibration pattern and the read vibration pattern are exceeding a first predefined threshold, electronic control unit 2 sends a warning signal;

S4.2 - if the differences between the memorized vibration pattern and the read vibration pattern are exceeding a second predefined threshold, considered as imposing a safety risk, electronic control unit 2 initiates the complete shut-off of anti-locking brake system module 1.

Failure diagnosing method implies inserting corresponding code lines into the software program of electronic control unit 2, as to be able to individually activate the mechanical components electric motor 3 and hydraulic valves 5, for example - to performing a diagnosis test, by this way the combo-sensor 2 reads the vibration patterns given out by electric motor 3 and by each valve 5 separately. The diagnosis test is to be performed every time the car starts.

While certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims .

	List	of reference signs
	1	Module e.g. anti-locking brake system module
	2	Electronic control unit of the module
5	3	Electric motor
	4	Valve block
	5	Valves
	6	Valve coils
	7	Combo-sensor
10	8	Printed-circuit board
	9	Electronic components

Claims

1. Method of diagnosing failure in an electronic control unit, operating as part of a module (1) , which electronic control unit (2) contains at least a mechanical component, at least an integrated sensor (7) able to detect vibration, and at least processing means able to recognize vibration patterns, characterized by that it includes the following steps:

(51) memorizing a normal vibration pattern provided by at least one mechanical component that move inside the electronic control unit (2) , in normal working condition; then, at every wake-up of the electronic control unit (2), performing a self-test by (52) reading the individual vibration pattern given out by any of the mechanical components that move inside the electronic control unit (2);

(53) comparing the memorized vibration pattern with the read vibration pattern for each mechanical component and evaluating the differences between the memorized vibration pattern and the read vibration pattern against predefined thresholds; and (54) initiating appropriate actions as warning or deactivating the module (1) .

2. Method according to claim 1, characterized by that the last step has as sub-step:

(S4.1) if the differences between the memorized vibration pattern and the read vibration pattern are exceeding a first predefined threshold, the electronic control unit (2) sends a warning signal.

3. Method according to claim 1, characterized by that the last step has as sub-step:

(S 4.2 ) if the differences between the memorized vibration pattern and the read vibration pattern are exceeding a second predefined threshold imposing a safety risk, electronic control unit (2) initiates the complete shut-off of the module (1).

4. Method of failure diagnosing according to claim 1-3, characterized by that the module (1) is an anti-locking brake system module containing as mechanical components an electric motor, hydraulic valves or a brake pump.

5. Method of failure diagnosing according to claims 1-3, characterized by that the first and second thresholds are predefined separately for each mechanical component.

6. Computer program to be run by the electronic control unit (2) , characterized by that integrates command lines as to be able to individually activate the mechanical components to perform a failure diagnosing test according to the method from previous claims .