DE102021100357A1 - Method for regenerating a particle filter in overrun mode - Google Patents

Abstract

There is a method for regenerating a particle filter of an internal combustion engine arrangement (1), which comprises an internal combustion engine (2) with a number of intake valves (4) and a particle filter (3) which is arranged downstream of the internal combustion engine (2) with respect to the exhaust gas flow, described. The method comprises the following steps: checking whether regeneration of the particle filter is required (14); Checking whether the temperature of the particle filter is above a specified minimum temperature for regeneration of the particle filter (13); Check whether the internal combustion engine is in overrun mode (12); if the internal combustion engine is in overrun mode, regeneration of the particulate filter is required and the temperature of the particulate filter is above a specified minimum temperature for regeneration of the particulate filter, starting regeneration (15), with the number of intake valves being opened (16) ; Determining the current loading of the particle filter (17); if the current loading of the particulate filter does not exceed a specified lower threshold, ending the regeneration with the number of intake valves being closed (18).

Description

The present invention relates to a method for regenerating a particle filter of an internal combustion engine arrangement. The invention also relates to a control device, an internal combustion engine arrangement, a vehicle, a computer-implemented method, a computer program product, a computer-readable storage medium and a data carrier signal.

In order to meet increasingly stringent emission requirements, particularly in Europe and China, particle filters (GPF—Otto Particulate Filters) are used in connection with internal combustion engines, for example engines or generators. In the case of an internal combustion engine, under normal operating conditions, the particulate filter reaches a temperature high enough to allow combustion of the stored carbon-based particulates. Air is supplied to the particle filter during deceleration phases. The oxygen available during deceleration phases and the high temperature inside the particle filter typically lead to more or less complete combustion of the particles stored in the filter.

However, particles stored in the particle filter form a so-called filter cake, which increases the filtering efficiency of the particle filter. If the particulate filter is regularly burned off completely during normal operating conditions, the filter is often in a clean condition with poorer filtration efficiency compared to a partially loaded filter. This is because, in the case of a clean filter, the filter cake that improves efficiency is not present. In order to achieve the desired filter efficiency even under unloaded conditions, the porosity of the filter must be low, but this leads to increased exhaust back pressure at high loads or with a loaded filter. This has a negative effect on fuel consumption and may cause the engine to knock.

In the document DE 10 2019 111 708 A1 a method and a system for particle filter generation is disclosed. In order to maintain a residual load during the regeneration of the filter, a secondary air flow upstream of the particle filter is interrupted when a corresponding threshold value is reached. Further prior art for operating particulate filters is in the documents DE 10 2016 222 325 A1 and DE 10 2018 211 195 A1 and DE 10 2019 100 025 A1 disclosed.

Oxygen is usually supplied to the particle filter via a secondary air pump in order to regenerate it. By adding oxygen to the exhaust gas reaching the particulate filter, regeneration can be initiated and controlled, at least as long as the engine is operated near steady state and stoichiometric. However, this method becomes problematic if a particle filter regeneration has already been initiated and then at the point in time at which the combustion should be stopped, the vehicle switches to overrun mode, i.e. a driving condition in which the engine is dragged through the vehicle without disconnected traction , i.e. kept in rotary motion. In overrun mode, the injection is switched off for reasons of consumption, so that air is then pumped through the engine into the exhaust system. However, this means that even when the secondary air pump is switched off, enough oxygen flows through the particle filter to cause further combustion. The consequence of this is that in these frequently occurring operating states, stopping regeneration in order to maintain a desired residual load does not work.

Against the described background, it is the object of the present invention to provide a method for regenerating a particle filter of an internal combustion engine arrangement, which makes it possible to maintain a minimum load on the particle filter as part of a regeneration thereof even during overrun operation. Further objects are to provide an advantageous control device, an internal combustion engine arrangement, a vehicle, a computer-implemented method, a computer program product, a computer-readable storage medium and a data carrier signal.

The stated objects are achieved by a method for regenerating a particle filter according to claim 1, a control device according to claim 8, an internal combustion engine arrangement according to claim 9, a vehicle according to claim 10, a computer-implemented method according to claim 11, a computer program product according to claim 12, a computer-readable storage medium according to Patent claim 13 and a data carrier signal according to patent claim 14 solved. The dependent claims contain further advantageous developments of the invention.

The method according to the invention for regenerating a particle filter of an internal combustion engine arrangement relates to an internal combustion engine arrangement which comprises an internal combustion engine with a number of intake valves and a particle filter. Here is the particle filter located downstream of the internal combustion engine with respect to the exhaust gas flow. The method according to the invention comprises the following steps: It is checked whether regeneration of a particle filter is required. This can be the case when the particle filter load exceeds a specified upper threshold value. It is also checked whether the temperature of the particle filter is above a specified minimum temperature for regeneration of the particle filter. In addition, it is checked whether the combustion engine is in overrun mode. The above steps can be performed simultaneously or in any order. In a next step, if the internal combustion engine is in overrun mode, regeneration of the particle filter is required and the temperature of the particle filter is above a specified minimum temperature for regeneration of the particle filter, regeneration is started. In doing so, the number of intake valves is opened. In a next step, the current loading of the particle filter is determined. If the current loading of the particle filter does not exceed a defined lower threshold value, for example it reaches it or falls below it, the regeneration is ended. In this case, the number of intake valves is closed.

The method according to the invention has the advantage that it enables a particle filter regeneration to be stopped even during overrun operation and thus ensures that a desired minimum loading of the particle filter can also be maintained in this case despite regeneration. Furthermore, no secondary air pump is required as part of the method and it is possible to control the desired minimum particle filter load in real driving operation.

Advantageously, checking whether regeneration of the particle filter is necessary includes determining the loading of the particle filter, preferably using a filter loading model. The loading model can be based on a previously measured map, for example. Based on the load and the engine speed, the instantaneous particle emissions are determined from the map and integrated during engine operation. In conjunction with an exhaust gas temperature model - which is common today - the burn-up of the filter can then also be simulated. Both models - loading and burn-up model - are then continuously monitored with the aid of the above-mentioned differential pressure sensor and, if necessary, recalibrated.

Additionally or alternatively, checking whether regeneration of the particulate filter is required may include determining the pressure differential across the particulate filter. The pressure at the inlet of the particle filter and at the outlet of the particle filter can therefore be measured and the difference can be evaluated (differential pressure method). A differential pressure sensor can preferably be used.

Checking whether the temperature of the particle filter is above a specified minimum temperature for regeneration of the particle filter can include determining the temperature of the particle filter using a catalyst temperature model. In addition or as an alternative to this, the temperature of the particle filter can be determined by measurement. Checking whether the internal combustion engine is in overrun mode can include detecting the current operating state, in particular the current operating point, using an engine controller. Using the variants mentioned, the parameters and input data required within the framework of the method can be recorded quickly and easily and without additional equipment.

The current loading of the particle filter is preferably determined using a loading model, in particular a filter loading model. The loading model is advantageously trained using data from differential pressure measurements described above. This has the advantage that the current residual load can be reliably estimated during the regeneration.

The opening and/or closing of the number of intake valves can take place by means of a valve control, which enables the degree of opening of the intake valves to be controlled independently of the engine control, ie by means of a so-called fully variable valve control.

The control device according to the invention for controlling the regeneration of a particle filter of an internal combustion engine arrangement is designed for an internal combustion engine arrangement which comprises an internal combustion engine with a number of intake valves and a particle filter. The control device includes a device for determining the loading of the particle filter, a device for determining the temperature of the particle filter, a device for detecting overrun operation of the internal combustion engine, for example a device for detecting the current operating state of the internal combustion engine, and a device for controlling the number of intake valves of the internal combustion engine independently of the engine control, i.e. a fully variable valve control. The control device is designed to carry out a previously described method according to the invention. The control device according to the invention tion has the features and advantages already mentioned above.

The internal combustion engine arrangement according to the invention comprises an internal combustion engine with a number of intake valves and a particle filter. The internal combustion engine arrangement includes a control device according to the invention or is designed to carry out a method according to the invention as described above. The vehicle according to the invention comprises an internal combustion engine arrangement according to the invention as described above. The internal combustion engine arrangement according to the invention and the vehicle according to the invention have the features and advantages already mentioned above. The vehicle can be a motor vehicle, a rail vehicle or a ship. The motor vehicle can be, for example, a passenger car, a truck, a bus, a minibus, a moped or a motorcycle.

The computer-implemented method according to the invention comprises instructions which, when the program is executed by a computer, cause the computer to carry out a method according to the invention as described above. The computer program product according to the invention comprises instructions which, when the program is executed by a computer, cause the latter to carry out a method according to the invention as described above. The computer-readable storage medium according to the invention comprises instructions which, when the program is executed by a computer, cause the computer to carry out a method according to the invention as described above. The data carrier signal according to the invention transmits the computer program product according to the invention. The computer-implemented method according to the invention, the computer program product according to the invention, the computer-readable storage medium according to the invention and the data carrier signal according to the invention have the features and advantages already mentioned above. They enable existing internal combustion engine arrangements to be retrofitted easily, quickly and inexpensively. Vehicles can thus be retrofitted to carry out the method according to the invention.

The invention is explained in more detail below using exemplary embodiments with reference to the attached figures. Although the invention is illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

The figures are not necessarily detailed or to scale and may be enlarged or reduced in order to provide a better overview. Therefore, the functional details disclosed herein are not to be taken as limiting, but merely as a basis for providing guidance for one skilled in the art to utilize the present invention in various ways.

• 1 zeigt schematisch ein erfindungsgemäßes Verfahren in Form eines Flussdiagramms.
• 2 zeigt schematisch eine erfindungsgemäße Steuervorrichtung.
• 3 zeigt schematisch eine erfindungsgemäße Verbrennungsmotoranordnung.
• 4 zeigt schematisch ein erfindungsgemäßes Fahrzeug.

As used herein, the term "and/or" when used in a series of two or more items means that each of the listed items can be used alone, or any combination of two or more of the listed items can be used. For example, when describing a composition containing components A, B and/or C, composition A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

• 1 shows schematically a method according to the invention in the form of a flowchart.
• 2 shows schematically a control device according to the invention.
• 3 shows schematically an internal combustion engine arrangement according to the invention.
• 4 shows schematically a vehicle according to the invention.

An embodiment of a method according to the invention is described below with reference to 1 explained in more detail. The method relates to controlling the regeneration of a particle filter of an internal combustion engine arrangement. The internal combustion engine assembly 1, which is exemplary in the 3 1 comprises an internal combustion engine 2 and a particulate filter 3 arranged downstream of the internal combustion engine 2 . The internal combustion engine 2 has a number of intake valves 4 .

The method starts with block 11. In step 12 it is checked whether the internal combustion engine is in overrun mode. If this is not the case, the method returns. If the engine is in overrun mode, the method continues with step 13. The check as to whether the internal combustion engine is in overrun mode can be carried out using an input signal from an engine controller, which provides information about the current operating point of the internal combustion engine. A corresponding input signal is in the 1 marked with the reference numeral 22.

In step 13, a check is made as to whether the temperature of the particle filter enables regeneration, that is to say specifically whether the temperature of the particle filter ters is above a specified minimum temperature for regeneration of the particle filter. If this is not the case, the method jumps back to step 12; if this is the case, the method continues with step 14. The temperature of the particle filter 3 can be detected, for example by measuring the temperature, or estimated, for example by means of a catalyst temperature model. A corresponding input signal containing the temperature of the particle filter is shown in FIG 1 marked with the reference numeral 23.

In step 14 it is checked whether regeneration of the particle filter is required. If this is not the case, the method jumps back to step 12; if this is the case, the method continues with step 15. The need for regeneration is assessed based on the current loading of the particle filter. For example, it may be specified that regeneration is required if the loading of the particulate filter exceeds a specified upper limit or threshold for loading. The current loading of the particle filter can be determined using the differential pressure method. A differential pressure sensor can be used for this purpose, with which the pressure difference across the particle filter is recorded. A corresponding input signal based on the differential pressure method is given in 1 marked with the reference numeral 25. In addition or as an alternative to this, the current loading of the particle filter can be estimated using a loading model. A corresponding model-based input signal is marked with reference number 24 . The filter loading model used is preferably trained using data collected using the aforementioned differential pressure method.

Steps 12, 13 and 14 can be performed in any order or simultaneously. The regeneration of the particle filter is started with step 15, ie when the engine is in overrun mode, regeneration of the particle filter is necessary and the temperature of the particle filter has a minimum temperature required for regeneration. To carry out the regeneration, the intake valves 4 are opened in step 16 in overrun mode.

In step 17 it is checked whether the current particle filter load exceeds a defined lower threshold value. This lower threshold is a desired residual load. The current loading of the particle filter is preferably estimated using a filter loading model. In principle, detection using the differential pressure method is also possible, but it requires a large number of measurements within a short period of time, which can possibly result in inaccuracies as a result of time delays. An input signal containing the current loading of the particle filter is in the 1 marked with the reference numeral 27.

If the current particle filter loading during the regeneration in step 17 is above the specified lower threshold value, the method jumps back to step 16 . If the current loading of the particulate filter is not above the specified lower threshold value, ie it reaches it or is below it, the method continues with step 18 . In step 18, the intake valves are closed in overrun mode. The regeneration is ended in this way. The end of the particle filter regeneration is in the 1 indicated by block 19.

The one in the 2 Schematically shown control device 5 according to the invention is for carrying out a method according to the invention, for example one in the 1 shown inventive method designed. The control device 5 shown comprises a device for determining the loading of the particle filter 6, a device for determining the temperature of the particle filter 7, a device for detecting overrun operation of the internal combustion engine 8 and a device for fully variable control of a number of intake valves of the internal combustion engine 9 the fully variable valve control is designed to control the degree of opening of the intake valves 4 as a function of input signals from the device for determining the loading of the particle filter 6, the device for determining the temperature of the particle filter 7 and the device for detecting overrun operation of the internal combustion engine 8.

The one in the 3 Internal combustion engine arrangement 1 shown comprises an internal combustion engine 2 with a number of intake valves 4 and an exhaust gas aftertreatment device with a particle filter 3 arranged downstream thereof .

the 4 shows a vehicle 10 according to the invention, for example a motor vehicle. As an alternative to this, the vehicle according to the invention can also be a rail vehicle or a ship. The vehicle 10 according to the invention comprises a basis of 3 described internal combustion engine arrangement according to the invention 1.

A computer-implemented method according to the invention, as well as a computer-readable storage medium, computer program product or data carrier signal according to the invention are, in relation to a method that can be executed by them using a computer, by the 1 flowchart shown.

Reference List

1

internal combustion engine arrangement

2

combustion engine

3

particle filter

4

intake valves

5

control device

6

Device for determining the loading of the particle filter

7

Device for determining the temperature of the particle filter

8th

Device for detecting overrun operation of the internal combustion engine

9

Device for fully variable control of a number of intake valves

10

vehicle

11

begin

12

Check whether the combustion engine is in overrun mode

13

Check whether the particle filter temperature allows regeneration

14

Check if regeneration of the particulate filter is required

15

Start regeneration of the particle filter

16

Open intake valves

17

Check whether the current particle filter load exceeds a defined lower threshold

18

Close intake valves

19

End

22

Input signal from engine control

23

Input signal including temperature of particulate filter

24

Estimated loading of the particulate filter using a loading model

25

Input signal particle filter loading from differential pressure

27

Input signal containing current loading of the particle filter

J

Yes

N

no

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102019111708 A1 [0004]
• DE 102016222325 A1 [0004]
• DE 102018211195 A1 [0004]
• DE 102019100025 A1 [0004]

Claims (14)

Method for regenerating a particle filter of an internal combustion engine arrangement (1) which comprises an internal combustion engine (2) with a number of intake valves (4) and a particle filter (3) which is arranged downstream of the internal combustion engine (2) with respect to the exhaust gas flow, characterized in that that the procedure comprises the following steps: - checking whether regeneration of the particle filter is required (14), - checking whether the temperature of the particle filter is above a specified minimum temperature for regeneration of the particle filter (13), - checking whether the internal combustion engine is in overrun mode (12), - if the internal combustion engine is in overrun mode, regeneration of the particulate filter is required and the temperature of the particulate filter is above a specified minimum temperature for regeneration of the particulate filter, starting regeneration (15), wherein the number of intake valves is opened (16), - Erm averaging the current loading of the particle filter (17), - if the current loading of the particle filter does not exceed a fixed lower threshold value, ending the regeneration, with the number of inlet valves being closed (18). procedure after claim 1 , characterized in that checking whether regeneration of the particle filter is required (14), determining the loading of the particle filter by means of a filter loading model (24) and/or determining the pressure difference across the particle filter (25). procedure after claim 1 or claim 2 , characterized in that checking whether the temperature of the particle filter is above a specified minimum temperature for regeneration of the particle filter (13) includes determining the temperature of the particle filter using a catalyst temperature model (23). Procedure according to one of Claims 1 until 3 , characterized in that checking whether the internal combustion engine is in overrun mode (12) includes detecting the current operating state by means of an engine controller (22). Procedure according to one of Claims 1 until 4 , characterized in that the loading of the particle filter is determined by means of a loading model (27). procedure after claim 5 , characterized in that the loading model is trained using data from differential pressure measurements. Procedure according to one of Claims 1 until 6 , characterized in that the opening and/or closing of the number of intake valves takes place by means of a valve control (9) which enables the degree of opening of the intake valves to be controlled independently of the engine control. Control device (5) for controlling the regeneration of a particle filter of an internal combustion engine arrangement (1), which comprises an internal combustion engine (2) with a number of intake valves (4) and a particle filter (3), the control device (5) having a device for determining the load of the particle filter (6), a device for determining the temperature of the particle filter (7), a device for detecting overrun operation of the internal combustion engine (8) and a device for controlling a number of intake valves (9) of the internal combustion engine independently of the engine control and to this is designed, a method according to one of Claims 1 until 7 to execute. Internal combustion engine arrangement (1), which comprises an internal combustion engine (2) with a number of intake valves (4) and a particle filter (3), characterized in that the internal combustion engine arrangement (1) has a control device (5). claim 8 comprises or is designed to include a method according to any one of Claims 1 until 7 to execute. Vehicle (10) having an internal combustion engine assembly (1). claim 9 includes. A computer-implemented method comprising instructions which, when the program is executed by a computer, cause the computer to carry out a method according to any one of Claims 1 until 9 to execute. Computer program product, comprising instructions which, when the program is executed by a computer, cause the latter to carry out a method according to any one of Claims 1 until 7 to execute. A computer-readable storage medium comprising instructions which, when the program is executed by a computer, cause the computer to carry out a method according to any one of Claims 1 until 7 to execute. Data carrier signal, which the computer program product according to Claim 13 transmits.

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