FR2906565A1 - Exhaust gas particle elimination system diagnosing method for motor vehicle, involves detecting defect of opening of switch and detecting functioning of electric source, and implementing elimination of particles by heating elements - Google Patents

Abstract

The method involves detecting defect of opening of a switch and functioning of an electric source (10). Elimination of particles is implemented by heating elements (12). A diagnostic and control module (21) controls opening and closing of the switch so as to permit elimination operation. A current intensity is measured to detect effective elimination operation of the elimination system and to detect stopping of the elimination using a measurement module (20). Independent claims are also included for the following: (1) a diagnostic device implementing exhaust gas particle elimination system diagnosing method (2) a motor vehicle comprising a diagnostic device.

Description

DIAGNOSTIC METHOD AND DEVICE FOR DIAGNOSING A SYSTEM

  The present invention relates to the field of reduction and elimination of particles contained in the exhaust gases of internal combustion engines. The invention more specifically relates to a method for diagnosing the functional state of a system for removing particles from the exhaust gas of a vehicle and a device implementing this method. Filtration and removal of soot particles devices, such as that proposed in document WO 2004/016913, make it possible, for example, to detect the fouling of a filter in order to trigger the regeneration, or to stop it. Such a device comprises a deposition zone where the soot particles are partly collected, and means for eliminating them comprising a heating element, such as an electrical resistance, connected to an electrical power supply enabling regeneration by combustion of the soot. According to the embodiment of the state of the art of FIG. 1, an exhaust gas soot particulate removal system comprises a series of parallel heating resistors 25 fed directly from the vehicle's electrical network by virtue of the switching on a switch. However, for such devices, it is not possible to diagnose the functional state of the disposal system itself. Indeed, it is not possible to ensure that the engagement action of the regeneration or deactivation of the particle removal is actually applied.

Another problem that arises when using a device comprising a plurality of heating resistors, is to detect the non-operation of one or more heating resistors. An object of the invention is therefore to provide a method 5 for diagnosing the operating state or malfunction of the device for filtering and removing exhaust particles. For this purpose, the object of the invention is to provide a method for diagnosing a system for removing particles from the exhaust gas of a vehicle, characterized in that it comprises: a first step of detecting the failure of opening a switch, - a second step of detecting the operation of an electrical source, is - a third step of operating the removal of particles by heating elements. The invention also relates to a diagnostic device implementing the method, comprising a system for removing particles from the exhaust gas of a vehicle, said disposal system comprising at least one electrical source, and at least one heating elements characterized in that said diagnostic device comprises a switch, a diagnostic and control module, and a module for measuring the voltage and current intensity of the elimination system.

Such a method and such a device implementing this method make it possible to keep a driver informed of the operating or malfunctioning state of the device for eliminating exhaust gas particles. The driver can thus know if the elimination system is faulty.

The invention advantageously makes it possible to know the nature of the failure of the elimination system, such as for example a failure of the switch in the open or closed state, or of the power supply. The method according to the invention advantageously makes it possible to detect the operation of one or more heating resistors of the heating resistors. According to other features of the invention - a diagnostic and control module can control the opening of the switch during the first step or when any failure is detected, can control the closing of the switch when of the third step in order to allow the elimination to be put into operation, - using a measuring module, it is possible to measure the intensity of the current to detect the putting into operation of the effective elimination of the system or for the purpose of detecting the final cessation of disposal, - the voltage of the disposal system may be measured to detect a failure of the supply system, or for the operation of the disposal, - first step can be performed when starting the vehicle during an initialization of the disposal system, - it is possible to perform the second step of detecting the presence of the electrical source when the interrupte ur is functional and when an elimination control command is active, it is possible to carry out the third step of operating the disposal when the disposal system is powered by the electrical source, the method may comprise a fourth step of detecting the failure of one or more heating elements 30 when the intensity measured by a measurement module is different from the theoretical intensity of the elimination system, 2906565 4 -on can detect the failure of one or more heating elements 30 minus one heating element by comparing the intensity of the measured current with the theoretical intensity of the disposal system and when the number of failing heating elements is greater than a predetermined tolerance threshold. The invention also relates to a motor vehicle comprising such a device for diagnosing the operating state or malfunction of an exhaust gas particle removal system, the heating elements being in the line of exhaust. Other characteristics and advantages of the invention will become clear from reading the following description of the non-limiting embodiment thereof, in conjunction with the accompanying drawings, in which: FIG. 1 represents an exemplary embodiment of a removal of soot particles from the exhaust gas as it exists in the prior art - Figure 2 shows a diagnostic device of the exhaust gas soot particle removal system according to the invention. FIG. 3 represents a flowchart representing the various steps of the method according to the invention. A system for removing exhaust gas soot particles as proposed in the prior art and in accordance with FIG. 1 comprises an electrical source 10, a switch 11, and heating elements 12, such as than heating resistors in parallel. A diagnostic device according to the invention as shown in FIG. 2 comprises the elimination system represented in FIG. 1, as well as a measurement module 20 and a diagnostic and control module 21.

The measuring module 20 comprises means for measuring the voltage V and the current I of the exhaust gas soot particles removal device. The diagnostic and control module 21 comprises means for diagnosing the operating state or malfunction of the disposal device as well as means for controlling the switch 11 to open or close it. In a preferred embodiment of the invention, the measurement module 20 is located between the electrical source 10 of the vehicle and the switch 11 for example. It will be understood that this location is given by way of non-limiting example, and that the measurement module 20 can be placed after the switch 11, or even elsewhere. The measurements of current I and voltage V made by the measurement module 20 are taken into account by the diagnostic and control module 21 in order to manage the state of the switch 11. The switch 11 which makes it possible to trigger the control of the elimination, is a simple switch. According to another variant of the invention not shown, the switch 11 is an integrated switch for example in an electronic current regulation module delivered to the heating resistors. The method for diagnosing the functional state of the elimination system is then performed during a diagnostic-specific sequence.

The method for diagnosing the functional state of the soot particle removal system includes a first step of detecting the failure of the switch 11 in the open state. The starting of the vehicle must trigger the opening of the switch 11. Thus, in this first step, the switch 11 receives an opening command via the diagnostic and control module 21. This first step is an initialization step which aims to open the switch 11 and verify that the order of opening has been made. It will be understood without departing from the context of the invention that the initialization can also be triggered at the request of the driver for example. To test the state of operation of the switch 11 in the open state, that is to say to know if the switch 11 has been opened, the diagnostic device orders the opening of the switch via the diagnostic and control module 21. The current I of the device supplied by the electrical source 10 to the equivalent resistance is then measured via the measuring module 20. For this purpose, when a test 31, the diagnostic device checks the presence or absence of current in the disposal system. A first diagnosis D1 of failure of the switch at the opening can be signaled to the driver in the form of a red light, for example when a presence of current is detected. Indeed, if a presence of current is detected, the switch 1 1, which is supposed to be open, is not actually. The diagnostic device then makes it possible to conclude that the switch 11 has failed to open.

However, if during this first step of detecting the failure of the switch 1 1, the intensity I of the measured current is substantially zero or less than a predetermined threshold value, the diagnostic and control module 21 deduces that the Soot particle removal system is in a stopped state. The disposal system is then ready to receive a control order CE removal of soot particles from a vehicle computer for example as soon as a trigger of the regeneration of the elimination and filtration system is performed. Thus, as soon as the disposal system receives an order of CE control to remove the soot particles, a second step of detecting the presence of the electrical source 10 is performed. For this purpose, the measurement module 20 takes the voltage V 2906565 7 at the terminals of the electric source 10 for example. During a test 32, if no voltage V is detected or if the detected voltage V is below a predetermined threshold value, the diagnostic and control module 21 makes it possible to diagnose a power supply fault of the control system. 'food. A second fault diagnosis D2 is then issued by the diagnostic device. A simple signal or message of failure or message in the form of red light or in sound form can be emitted. The driver then knows that there is a power failure of the disposal system. However, if during the test 32, a presence of the electrical source is detected, the diagnostic and control module 21 allows a third step of operating the elimination by controlling the closing of the switch 11. is L ' switch must be open to detect the operation of the disposal system. This is only when a command order of the elimination is received by the diagnostic device and when the switch 11 closes that elimination can start. In this third step, it is thus verified that the closing order of the switch 11 has been executed. The detection of a possible failure of the switch 11 when it is closed makes it possible to check whether the operation of the elimination is effective or not. Indeed, if the switch fails and does not close, the third step of operating the elimination can not be done. To detect a possible failure of the switch 11 in the closed state, the intensity I of the current is again measured by means of the measurement module 20 and this measurement is tested in a test 33. In this case, test 33, if the intensity I measured is zero or substantially less than a predetermined threshold value, the switch 11, which is supposed to be closed, is therefore on the contrary remained open, and the effective operation of the elimination 2906565 8 did not take place. The removal of the particles can not then take place. The diagnostic and control module 21 then detected a failure of the closing of the switch 11. A diagnostic message D3 is sent to the driver in the form of a red light, for example to signal a failure of the switch when of its closure. On the other hand, a non-zero measurement of the intensity I of the current or substantially greater than a predetermined threshold value during the test 33 makes it possible for the diagnostic and control module 21 to detect effective start-up of the elimination. The diagnostic device deduces that the third step of operating the elimination has gone well and the diagnostic device can then go to a fourth step of detecting the failure of one or more heating elements 12. is To do this, the diagnostic and control module 21 checks whether or not the heating elements 12 are faulty by first carrying out a test 34. This test 34 makes it possible to detect the failure of one or more heating resistors 12 according to the value of the intensity I of the current 20 measured by means of the measurement module 20. In fact, during the test 34, the measurement of the intensity I of the current is substantially equal to that of the measured voltage V divided by the equivalent resistance, the diagnostic device performs a test 36, which checks whether the elimination control command not shown in Figure 3, is still active or not, and explained in following the description. However, if the intensity I measured does not correspond to the expected value, namely the value of the quotient of the measured voltage V divided by the value of the equivalent resistance, then the diagnostic and control module 21 concludes that there is a failure due to the heating resistors 12, and evaluates the number of failing resistors ERD. A test 35 is then performed to determine whether or not the number of failing heaters has exceeded a predetermined acceptable tolerance threshold. The number of failing resistors is for example compared to the predetermined tolerance threshold.

If the number of failing resistors is unacceptable and exceeds the accepted tolerance, the diagnostic device issues a diagnostic message D4 indicating that the disposal system has failed. On the other hand, if during the test 35, the number of failing resistors is acceptable, or if there is no faulty resistance, or else, then the diagnostic device carries out the test 36. If during this test 36, the order of removal of soot particles is no longer active, the diagnostic and control module 21 causes the opening of the switch and the diagnosis is then completed. An audible or visual message may be sent to the driver informing him about the end of the diagnosis. An end of diagnosis message is sent to the driver to warn him of the stoppage of operation. If during the test 36, the elimination control command is still active, the measurement module 20 takes the voltage V across the electrical source 10 to check the supply of the disposal system. A test 37 is then performed to verify the presence or absence of voltage V. When the measured voltage V is substantially zero, the diagnostic device issues the diagnosis D2 of the aforementioned power supply fault. On the other hand, if the measured voltage V is not substantially zero, the measurement module takes the intensity I of the current and the following test performed by the diagnostic and control module 21 is the test 33. The next step performed by the diagnostic device is then the fourth step of detecting the failure of one or more heating elements.

According to a preferred embodiment of the invention, and in accordance with FIG. 3, when one of the failure diagnostic messages mentioned in the description above is issued by the diagnostic device, another diagnostic message 5 of elimination failure D5 is then sent to the driver. The diagnostic and control module 21 causes the switch 11 to open and a new end-of-diagnosis message is issued. It will be understood that the diagnostic device can send a single final message of failure of the disposal system without specifying the nature of the defect of the disposal system by triggering the opening of the switch 11. For any detected fault, the Failure signal is sent to the driver and / or vehicle diagnostic system. Similarly, the activation of the diagnostic device may, in another embodiment not shown, be performed at the request of the driver instead of being performed automatically at startup, the choice being left to the driver. The diagnostic method and the diagnostic device implementing this method make it possible to know the nature of a possible failure of the elimination system by detecting the non-operation of one or more heating elements, the non-functioning of the supply. electric, or the failure of the switch.

This diagnostic method and the diagnostic device according to the invention thus make it possible to detect whether the elimination system is functional or not, and whether the activation or deactivation of the elimination commands are applied.

Claims (12)

  1. A method of diagnosis of a system for removing particles from the exhaust gas of a vehicle characterized in that it comprises: i. a first step of detecting the failure to open a switch (1 1), ii. a second step of detecting the operation of an electrical source, iii. a third step of operating the removal of particles by heating elements. is   2. Method according to claim 1 characterized in that a diagnostic and control module (21) controls the opening of the switch (1 1) in the first step or when any failure is detected, and it controls the closing of the switch (1 1) in the third step 20 to allow the start of operation elimination.   3. Method according to claim 1 or 2, characterized in that, by means of a measurement module (20), the intensity (I) of the current is measured to detect the start of operation of the actual elimination of the disposal system or to detect the definitive cessation of the elimination   4. Method according to claim 1 or 2, characterized in that the voltage (V) of the elimination system is measured to detect a failure of the power supply system.   5. Method according to claim 1 or 2 characterized by measuring the voltage (V) of the elimination system for operating the elimination. 5   6. Method according to one of the preceding claims characterized in that the first step is performed when starting the vehicle during an initialization of the elimination system.   7. Method according to one of the preceding claims characterized in that the second step of detecting the presence of the electrical source (10) when the switch (1 1) is functional and when a control order of elimination is active.   8. Method according to one of the preceding claims characterized in that it carries out the third step of operating the elimination when the disposal system is powered by the electrical source. 20   9. Method according to one of the preceding claims characterized in that it comprises a fourth step of detecting the failure of one or more of the heating elements when the intensity (I) measured by a measuring module (20) is 25 different from the theoretical intensity (I) of the elimination system   10. Method according to one of the preceding claims characterized in that detects the failure of at least one heating element by comparing the intensity (I) of the measured current 30 with the theoretical intensity (I) of the system of elimination and when the number of failing heating elements is greater than a predetermined tolerance threshold. 15 2906565 13   11. Diagnostic device implementing the method according to the preceding claims, comprising a system for removing particles from the exhaust gas of a vehicle, said elimination system comprising at least one electrical source (10), and at least one heating element (12) characterized in that said diagnostic device comprises a switch (11), a diagnostic and control module (21), and a measuring module (20) for the voltage (V) and the intensity (I) of the current of the disposal system.   12. A motor vehicle comprising a device for diagnosing the operating state or malfunction of an exhaust gas particle removal system, characterized in that said diagnostic device is according to the preceding claim, the heating elements being in the exhaust line.