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EP-4735748-A1 - METHOD FOR DIAGNOSING A DRIVE DEVICE OF A MOTOR VEHICLE, AND MOTOR VEHICLE

EP4735748A1EP 4735748 A1EP4735748 A1EP 4735748A1EP-4735748-A1

Abstract

The invention relates to a method for diagnosing a drive device (10), which has an internal combustion engine (12), of a motor vehicle that can be driven by means of an internal combustion engine (12), wherein the drive device (10) has components (60a-c), by means of which the composition of exhaust gas of the internal combustion engine (12) can be influenced and/or detected. For each component (60a-c), an electronic computing device (62) is used to carry out at least one respective diagnostic method which is assigned to each component (60a-c) and by means of which, for each component (60a-c) assigned to the respective diagnostic method, at least one respective current characteristic is ascertained which is assigned to the respective component (60a-c) and which characterizes the respective current state of the respective component (60a-c). The electronic computing device (62) is used to ascertain at least one change value of a constituent of the exhaust gas, said change value being assigned to the respective component.

Inventors

  • Mathein, Dominik

Assignees

  • Mercedes-Benz Group AG

Dates

Publication Date
20260506
Application Date
20240709

Claims (8)

  1. 1. A method for diagnosing a drive device (10) having an internal combustion engine (12) of a motor vehicle that can be driven by the internal combustion engine (12), in which: - the drive device (10) has components (60a-c) by means of which a composition of exhaust gas of the internal combustion engine (12) can be influenced and/or detected; - by means of an electronic computing device (62) for the respective component (60a-c) at least one respective diagnostic method assigned to the respective component (60a-c) is carried out, by means of which at least one respective current characteristic value assigned to the respective component (60a-c) is determined for the respective component (60a-c) to which the respective diagnostic method is assigned, which characteristic value characterises a respective current state of the respective component (60a-c); - by means of the electronic computing device (62) for the respective component (60a-c) for the current characteristic value assigned to the respective component (60a-c) in dependence on at least one respective characteristic map stored in the electronic computing device (62) and assigned to the respective component (60a-c), a respective change value assigned to the respective component (60a-c) related to a respective initial value for a respective component of the exhaust gas is determined; - the respective change values of the components (60a-c) are compared with one another by means of the electronic computing device (62), whereby the largest of the respective change values is determined; and - for the component (60a-c) to which the largest of the change values is assigned: o an entry is stored in a data memory of the electronic computing device (62); and/or o an indication signal that can be perceived visually and/or haptically and/or acoustically by a person is output by means of a playback device of the motor vehicle.
  2. 2. Method according to claim 1, characterized in that: - by means of the electronic computing device (62), the respective change value is compared with a respective assigned limit value, wherein: o the change values are compared with one another by means of the electronic computing device if it is determined by comparing the respective change value with the respective limit value that at least one of the change values exceeds the respectively assigned limit value; and/or o an error entry is stored and/or a further indication signal is output for the component (60a-c) to which the largest of the change values is assigned if it is determined by comparing the respective change value with the respective limit value that at least one of the change values exceeds the respectively assigned limit value; and/or - the change values are summed up by means of the electronic computing device (62), whereby a sum value is formed which is compared by means of the electronic computing device with the assigned limit value, wherein: o the change values are summed up by means of the electronic computing device if it is determined by comparing the sum value with the limit value that the sum value exceeds the limit value; and/or o the error entry is stored and/or the further indication signal is output for the component (60a-c) to which the largest of the change values is assigned if it is determined by comparing the sum value with the limit value that the sum value exceeds the limit value.
  3. 3. Method according to claim 1 or 2, characterized in that by means of the electronic computing device (62) the change values are sorted in ascending or descending order by comparing the change values.
  4. 4. Method according to one of the preceding claims, characterized in that the respective characteristic map assigns the respective change value to the respective characteristic value for the respective component (60a-c) to which the respective characteristic map is assigned.
  5. 5. Method according to one of the preceding claims, characterized in that the components (60a-c) comprise: - the internal combustion engine (12) and/or - at least one injector for introducing a fuel into at least one combustion chamber (16) of the internal combustion engine (12) and/or - at least one catalyst for aftertreating the exhaust gas and/or - at least one lambda probe for measuring a measured variable characterising a residual oxygen content in the exhaust gas and/or - at least one nitrogen oxide sensor for measuring a quantity characterising a quantity of nitrogen oxides contained in the exhaust gas and/or - at least one particulate filter to filter out soot particles from the exhaust gas.
  6. 6. The method according to claim 5, characterized in that the catalyst comprises a three-way catalyst and/or an oxidation catalyst and/or an SCR catalyst.
  7. 7. Method according to one of the preceding claims, characterized in that the characteristic values comprise: - at least one oxygen storage value which characterises an amount of oxygen that can be stored in at least one of the components, and/or - at least one value characterising the response behaviour of a lambda probe.
  8. 8. A motor vehicle which is designed to carry out a method according to one of the preceding claims.

Description

Method for diagnosing a drive device of a motor vehicle and motor vehicle The invention relates to a method for diagnosing a drive system of a motor vehicle, in particular a car. Furthermore, the invention relates to a motor vehicle, in particular a car. DE 102021 127 196 A1 discloses a computer-implemented method for diagnosing a deterioration of at least one component of a technical system. The object of the present invention is to provide a method and a motor vehicle so that a particularly advantageous diagnosis of a drive device of the motor vehicle can be realized. This object is achieved by a method having the features of patent claim 1 and by a motor vehicle having the features of patent claim 8. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims. A first aspect of the invention relates to a method for diagnosing a drive device of a motor vehicle, also referred to simply as a vehicle, which is preferably designed as a motor vehicle, in particular as a passenger car. In the method, the drive device has an internal combustion engine, also referred to as an internal combustion engine, motor or internal combustion engine, by means of which the motor vehicle can be driven. The internal combustion engine can be operated in a fired mode, in which combustion processes take place in the internal combustion engine, and in particular, it is provided that in the method, the internal combustion engine is operated in the fired mode, so that in the internal combustion engine, in particular in The combustion processes mentioned take place in the combustion chambers of the internal combustion engine. During each combustion process, a respective fuel-air mixture, also simply referred to as a mixture, is combusted, resulting in exhaust gas from the internal combustion engine. Thus, the internal combustion engine can provide exhaust gas. Preferably, the internal combustion engine provides the exhaust gas in the method. In the method, the drive device has components by means of which the composition of the exhaust gas of the internal combustion engine can be influenced and/or detected. The feature that, for example, the composition of the exhaust gas can be detected by means of the respective component is to be understood in particular that at least one measured variable can be detected by means of the component, which here characterizes at least one component of the exhaust gas, thus at least one chemical substance contained in the exhaust gas, also simply referred to as a substance. The chemical substance is to be understood as an element, a compound or a mixture. During combustion of hydrocarbon-air mixtures, the exhaust gas contains, among other things, the components CO, NMHC and NOx. In the method, at least one respective diagnostic method assigned to the respective component, also referred to as an individual diagnostic method, is carried out for the respective component by means of an electronic computing device, in particular of the motor vehicle, by means of which at least one respective current characteristic value, in particular a respective characteristic variable, assigned to the respective component is determined for the respective component to which the respective diagnostic method is assigned, which characterizes a respective current state of the respective component. Thus, for example, the respective current characteristic value characterizes the respective current characteristic variable that characterizes the respective state of the respective component. The electronic computing device is or comprises, for example, at least or exactly one electronic computing unit, also referred to as a control unit. Furthermore, it is conceivable that the electronic computing device has a plurality of electronic computing units, also referred to as control units, which are coupled to one another, for example, in particular via a data bus, in particular in such a way that the computing units can exchange data. In the method, the electronic computing device is used for the respective component, in particular related to a respective output value of a respective component of the exhaust gas, depending on the respective characteristic value assigned to the respective component and depending on at least one A respective change value of the exhaust gas constituent, in particular a change quantity, is determined from the respective characteristic map stored in the electronic computing device, in particular in an electrical or electronic data memory of the electronic computing device, and assigned to the respective component, which can be designed, for example, as a two-dimensional, a three-dimensional, up to an n-dimensional characteristic map and/or also as a characteristic curve, wherein the respective change value characterizes a change in the initial value that can be brought about by the respective component in its current aged or deteriorated state. The