Detecting a modification of a particle filter for an exhaust branch of a motor vehicle

Abstract

A system for identifying a modification of a component in an exhaust gas line of a motor vehicle, includes a particulate filter, a diagnostic system, a first temperature sensor, a second temperature sensor, and an evaluation unit. The evaluation unit is configured to receive from the first temperature sensor a first temperature variable which is characteristic of a first exhaust gas temperature and to receive from the second temperature sensor a second temperature variable which is characteristic of a second exhaust gas temperature. The evaluation unit is also configured to compare the temperature variables or comparison variables which are derived therefrom with each other. Depending on the comparison, the evaluation unit is also configured to determine a modification of the particulate filter.

Claims

1. A system for identifying a modification of a component in an exhaust gas line of a motor vehicle, comprising: a particulate filter having at least a first filter unit and a second filter unit which are arranged in parallel with each other in the exhaust gas line, a diagnostic system having an evaluation unit and at least a first temperature sensor and a second temperature sensor, wherein the first temperature sensor is arranged downstream in terms of an exhaust gas flow behind the first filter unit, the second temperature sensor is arranged downstream in terms of the exhaust gas flow behind the second filter unit, and the evaluation unit is configured to: receive from the first temperature sensor a first temperature variable which is characteristic of a first exhaust gas temperature and to receive from the second temperature sensor a second temperature variable which is characteristic of a second exhaust gas temperature, compare the first and second temperature variables or first and second comparison variables which are derived therefrom with each other, and depending on the comparison, to determine the modification of the particulate filter, wherein the evaluation unit is also configured to: determine a temperature difference between the first and second temperature variables which were received, and when a threshold value for the temperature difference is reached or exceeded, to determine the modification of the particulate filter.

2. The system according to claim 1, wherein the evaluation unit is also configured, when the threshold value for the temperature difference is reached or exceeded, to: by comparing each temperature variable received, establish a temperature sensor of the at least first and second temperature sensors whose temperature variable in comparison with each of the respective temperature variables of the other at least first and second temperature sensors in each case is characteristic of a highest exhaust gas temperature, and determine the modification of the filter unit which is located in the exhaust gas line upstream in terms of the exhaust gas flow in front of the established temperature sensor.

3. The system according to claim 1, wherein the first comparison variable is a temperature gradient of the first temperature variable, and the second comparison variable is a temperature gradient of the second temperature variable, and the evaluation unit is also configured to: determine a gradient difference between each determined temperature gradients, and when a threshold value for the gradient difference is reached or exceeded, to determine the modification of the particulate filter.

4. The system according to claim 3, wherein the evaluation unit is also configured, when the threshold value for the gradient difference is reached or exceeded, to: by comparing each determined temperature gradient, establish a temperature sensor of the at least first and second temperature sensors whose respective temperature gradient in comparison with each of the respective temperature gradients of the other at least first and second temperature sensors is characteristic of a greatest change of the exhaust gas temperature, and determine the modification of the filter unit which is located in the exhaust gas line upstream in terms of the exhaust gas flow in front of the established temperature sensor.

5. The system according to claim 4, wherein the evaluation unit is also configured to: receive, or determine by means of a model, a first pressure variable which is characteristic of an exhaust gas pressure upstream in terms of the exhaust gas flow in front of the particulate filter from a first pressure sensor which is included in the diagnostic system and which is located upstream in terms of the exhaust gas flow in front of the particulate filter, receive, or determine by means of a model, a second pressure variable which is characteristic of an exhaust gas pressure downstream in terms of the exhaust gas flow behind the particulate filter from a second pressure sensor which is included in the diagnostic system and which is located downstream in terms of the exhaust gas flow behind the particulate filter, determine a deviation of the received or determined first and second pressure variables, and when a value has reached or fallen below a threshold value for the deviation of the received or determined first and second pressure variables, to determine the modification of the particulate filter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a conventional system for identifying a modification of a particulate filter;

(2) FIG. 2 shows an inventive system for identifying a modification of a particulate filter; and

(3) FIG. 3 shows a procedure of the inventive method.

DETAILED DESCRIPTION OF THE DRAWINGS

(4) FIG. 1 shows a conventional system for identifying a modification of a particulate filter.

(5) In this instance, the particulate filter OPF is arranged in the exhaust gas line downstream in terms of the exhaust gas flow behind an internal combustion engine VM.

(6) The conventional system comprises an evaluation unit AE and a first temperature sensor T1 and a second temperature sensor T2, wherein the first temperature sensor T1 is arranged upstream in terms of the exhaust gas flow in front of the particulate filter OPF and the second temperature sensor T2 is arranged downstream in terms of the exhaust gas flow behind the particulate filter OPF.

(7) The evaluation unit AE is configured to receive from the first temperature sensor T1 a first temperature variable which is characteristic of a first exhaust gas temperature, and to receive from the second temperature sensor T2 a second temperature variable which is characteristic of a second exhaust gas temperature, to compare the temperature variables or comparison variables which are derived therefrom with each other and, depending on the comparison, to determine a modification of the particulate filter OPF.

(8) In particular in this instance, a modification of the particulate filter OPF is determined when the temperature variables are substantially identical.

(9) FIG. 2 shows an inventive diagnostic system for identifying a modification of a particulate filter OPF of an exhaust gas line of a motor vehicle.

(10) In this instance, the particulate filter OPF is arranged downstream in terms of the exhaust gas flow behind an internal combustion engine VM in the exhaust gas line.

(11) The particulate filter OPF comprises at least a first filter unit OPF1 and a second filter unit OPF2 which are arranged parallel with each other in the exhaust gas line.

(12) Furthermore, the diagnostic system comprises an evaluation unit AE and at least a first temperature sensor T2 and a second temperature sensor T2′, wherein the first temperature sensor T2 is arranged downstream in terms of the exhaust gas flow behind the first filter unit OPF1 and the second temperature sensor T2′ is arranged downstream in terms of the exhaust gas flow behind the second filter unit OPF2.

(13) This evaluation unit AE is configured to receive from the first temperature sensor T2 a first temperature variable which is characteristic of a first exhaust gas temperature and to receive from the second temperature sensor T2′ a second temperature variable which is characteristic of a second exhaust gas temperature.

(14) Furthermore, the evaluation unit is configured to compare the temperature variables or comparison variables which are derived therefrom with each other and, depending on the comparison, to determine a modification of the particulate filter OPF.

(15) FIG. 3 shows an embodiment of the inventive diagnostic method for identifying a modification of a particulate filter OPF for an exhaust gas line of a motor vehicle, wherein the particulate filter OPF comprises at least a first filter unit OPF1 and a second filter unit OPF2, which are fitted parallel with each other in the exhaust gas line.

(16) One step of the method is receiving 100 a first temperature variable which is characteristic of a first exhaust gas temperature downstream in terms of the exhaust gas flow behind the first filter unit OPF1.

(17) Another step of the method is receiving 110 a second temperature variable which is characteristic of a second exhaust gas temperature downstream in terms of the exhaust gas flow behind the second filter unit OPF2.

(18) Another step of the method is the comparison 120 of the temperature variables or comparison variables which are derived therefrom with each other.

(19) In particular, a temperature difference between the temperature variables received can be determined as a comparison of the temperature variables.

(20) Alternatively, in particular the first comparison variable may be a temperature gradient of the first temperature variable and the second comparison variable may be a temperature gradient of the second temperature variable.

(21) As a comparison of the comparison variables, it is then possible, for example, to determine a gradient difference between the determined temperature gradients.

(22) Another step of the method is determining 130 a modification of the particulate filter OPF depending on the comparison.

(23) Particularly if, as a comparison, a temperature difference between the temperature variables received was determined, when a threshold value for the temperature difference is reached or exceeded, the modification of the particulate filter OPF can be determined.

(24) If, alternatively, as a comparison, a gradient difference between temperature gradients was determined, particularly when reaching or exceeding a threshold value for the gradient difference the modification of the particulate filter OPF can be determined.

(25) In particular, a partial disassembly 135 of the first filter unit OPF1 or a partial disassembly of the second filter unit OPF2 can be determined as a modification of the particulate filter OPF.

(26) Particularly when, as a comparison, a temperature difference between the temperature variables received was determined, by comparing the temperature variables received it is possible to determine the temperature sensor T2 whose temperature variable in comparison with the temperature variable of the other temperature sensor T2′ is characteristic of the highest exhaust gas temperature. Subsequently, the modification of the filter unit OPF1 which is located in the exhaust gas line upstream in terms of the exhaust gas flow in front of the established temperature sensor T2 can be determined.

(27) Particularly when, alternatively, as a comparison, a gradient difference has been determined, by comparing the determined temperature gradients it is possible to determine the temperature sensor T2 whose temperature gradient in comparison with the temperature gradient of the other temperature sensor T2′ is characteristic of the greatest change of the exhaust gas temperature. Subsequently, the modification of the filter unit OPF1, which is located in the exhaust gas line upstream in terms of the exhaust flow in front of the established temperature sensor T2 can be determined.

(28) If no modification of the particulate filter OPF was previously determined, another step of the method is receiving 140 a first pressure variable which is characteristic of the exhaust gas pressure upstream in terms of the exhaust flow in front of the particulate filter OPF from a pressure sensor P which is included by the diagnostic system and which is located upstream in terms of the exhaust gas flow in front of the particulate filter OPF.

(29) Another step of the method is then determining 150 a second pressure variable which is characteristic of the exhaust gas pressure downstream in terms of the exhaust gas flow behind the particulate filter OPF using a model.

(30) Another step of the method is determining 160 a deviation of the pressure variable received and the pressure variable determined by means of the model.

(31) Another step of the method is determining 170 a modification of the particulate filter OPF when a value reaches or falls below a threshold value for the deviation of the received or determined pressure variables a modification of the particulate filter OPF.

(32) It is possible in particular to determine a complete disassembly 175 of the particulate filter OPF as a modification of the particulate filter OPF, that is to say, a disassembly of the first filter unit OPF1 and a disassembly of the second filter unit OPF2.

(33) Otherwise, it can also be determined (180) that the particulate filter OPF has not been modified.