METHOD AND SYSTEM FOR CONTROLLING AN INTERNAL COMBUSTION ENGINE AND/OR AN EXHAUST AFTERTREATMENT DEVICE OF A VEHICLE, VEHICLE WITH SUCH A SYSTEM, AS WELL AS COMPUTER PROGRAM PRODUCT FOR CARRYING OUT SUCH A METHOD AND CONTROL UNIT WITH SUCH A COMPUTER PROGRAM PRODUCT

Abstract

A method and systems are disclosed for controlling the exhaust emissions an internal combustion engine of a vehicle. The driving state of the vehicle is determined and corresponding driving state signals are generated with the aid of driving state detectors. The emission values of the exhaust gases emitted by the internal combustion engine are determined based on the driving state signals by a computer model stored in a control unit. The determined emission values are compared with predefined emission limits by the control unit. If the determined emission values exceed the predefined emission limits, the internal combustion engine and/or the exhaust aftertreatment device are controlled by the control unit such that the determined emission values are reduced until they lie below the predefined emission limits.

Claims

1-12. (canceled)

13. A method for controlling at least one of an internal combustion engine and an exhaust gas aftertreatment device of a vehicle comprising: determining a driving state of the vehicle using at least one driving state detector; generating driving state signals based on the determined driving state; determining an emission value of exhaust gases emitted by the internal combustion engine based on the driving state signals and a computer model stored in a control unit; comparing the determined emission value to a predefined emission limit with the control unit; and controlling at least one of the internal combustion engine and the exhaust gas aftertreatment device with the control unit when the determined emission values exceed the predefined emission limits such that the determined emission values are reduced until they lie below the predefined emission limits.

14. The method according to claim 13, further comprising averaging the determined emission values over a predefined time period and comparing the averaged determined emission value to the predefined emission limit with the control unit.

15. The method according to one of claims 13, determining the driving state using a driving time, a speed of the vehicle, an acceleration of the vehicle, a power output of the internal combustion engine , and at least one of a CO.sub.2 emission or a NO.sub.x emission of the internal combustion engine.

16. The method according to claim 13, further comprising controlling the internal combustion engine with the control unit such that an air-fuel ratio of an air-fuel mixture fed to the internal combustion is varied in order to reduce the determined emission values.

17. The method according to claim 13, further comprising controlling the internal combustion engine with the control unit such that an overlapping period of the intake valve and the exhaust valve of the internal combustion are varied for reducing the determined emission values.

18. The method according to claim 13, further comprising varying a volume of the combustion air fed to the internal combustion engine using at least one control valve such that the emission values are reduced, wherein the control unit is configured to control the at least one control valve.

19. The method according to claim 13, wherein determining the driving state of the vehicle further comprises accounting for a current position of the vehicle.

20. The method according to claim 13, wherein the emission limits correspond to a regulated emission standard.

21. A non- transitory machined readable medium comprising a computer program product having a program code stored thereon, which when executed on a processor is configured to out the method according to claim 13.

22. A control unit comprising a non-transitory machine readable medium according to claim 21 and a processor configured to execute the program code.

23. A system for controlling at least one of an internal combustion engine and an exhaust gas aftertreatment device comprising: driving state detectors configured to determine the driving state of the vehicle and generate corresponding driving state signals; and a control unit having a computer model relating the emission values of the exhaust gases emitted by the internal combustion engine based on the driving state signals with consideration of predefined boundary conditions, the control unit configured to: determine an emission value of exhaust gases emitted by the internal combustion engine based on the driving state signals and the computer model; compare the determined emission value with a predefined emission limit; and control at least one of the internal combustion engine and the exhaust gas aftertreatment device when the determined emission values exceed the predefined emission limits such that the determined emission values are reduced until they lie below the predefined emission limits.

24. A vehicle comprising an internal combustion engine, an exhaust gas aftertreatment device and a system according to claim 23.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements.

[0035] FIG. 1 shows a basic representation of a vehicle with an internal combustion engine that is controlled with the proposed method;

[0036] FIG. 2 shows a schematic representation of the proposed determination of the driving state; and

[0037] FIG. 3 shows a flowchart of the proposed method.

DETAILED DESCRIPTION

[0038] The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description.

[0039] FIG. 1 shows a basic representation of a vehicle 10 with an internal combustion engine 12 and an exhaust aftertreatment device 13 that can be controlled with a method described in greater detail below. In order to control the internal combustion engine 12 and/or the exhaust aftertreatment device 13, the vehicle 10 includes a system 14 having a control unit 16. The control unit 16 cooperates with a plurality of driving state detectors 18, which determine different parameters that characterize the current driving state and convert these parameters into corresponding driving state signals. In the example shown, the driving state detectors 18 include speed sensors 20 that detect the current speed of the vehicle 10. The driving state detectors 18 also include an acceleration sensor 22, by which the current acceleration of the vehicle 10 can be determined. In addition, the driving state detectors 18 include a NO.sub.x sensor 24, by which the current emission values of different nitrogen oxides emitted by the internal combustion engine 12 can be determined. The driving state detectors 18 furthermore include a tachometer 26 for determining the current speed of the internal combustion engine 12, as well as a fuel quantity measuring device 28 for determining the fuel quantity injected into the combustion chamber of the internal combustion engine 12 by a not-shown fuel pump.

[0040] A computer model 30, which processes the signals generated by the driving state detectors 18 as described below and controls the internal combustion engine 12 and/or the exhaust aftertreatment device 13 accordingly, is stored in the control unit 16.

[0041] FIG. 2 shows a schematic representation of the proposed determination of the driving state. As already mentioned above, the driving state may be characterized by a number of parameters that are determined by the driving state detectors 18. For example, the speed and acceleration sensors 20, 22 directly determine the current value of the corresponding parameter and to feed this parameter to the control unit 16. There are also parameters that in fact describe the driving state, but cannot be directly evaluated by the computer model 30. For example, one interesting parameter is the current power output of the internal combustion engine 12, which cannot be directly derived from the engine speed. The engine speed determined by the tachometer 26 therefore is initially fed to an additional computer model 32, in which a characteristic diagram specific to the respective internal combustion engine is stored. The power output can be deduced from this characteristic diagram based on the current engine speed and other parameters such as, for example, the volume of air fed to the internal combustion engine and the output torque. The additional computer model 32 may either form part of the driving state detectors 18 or part of the computer model 30.

[0042] FIG. 3 shows an embodiment of the proposed method for controlling the internal combustion engine 12 in the form of a flowchart. In a first step S1, the current driving state of the vehicle 10 is determined in the above-described fashion with the aid of the driving state detectors 18. The emission values of the exhaust gases currently emitted by the internal combustion engine 12 are derived from the determined driving state in a step S2. In a subsequent step S3, it is checked if the determined emission values lie above or below predefined emission limits. The emission limits may be specified, for example, in legal regulations. If the determined emission values lie below the emission limits, the internal combustion engine 12 is operated in unchanged form such that the control unit 16 does not intervene in the operation of the internal combustion engine 12 (S4). If the determined emission values lie above the emission limits, the control unit 16 controls the internal combustion engine 12 in such a way that the subsequently determined emission values lie below the predefined emission limits (S5). To this end, steps S1 to S3 are continuously repeated and countermeasures are either initiated or not depending on the result of the comparison. In this case, the control unit 16 can select the most effective countermeasure for reducing the emission values in the determined driving state from a plurality of available countermeasures.

[0043] The control unit 16 may assume control of the internal combustion engine 12 when it can be ascertained that the emission values of the exhaust gases emitted by the internal combustion engine 12 will soon exceed the emission limits. To this end, a preliminary emission limit may be specified and the internal combustion engine 12 can be controlled such that emissions are reduced once this preliminary emission limit is exceeded in order to prevent the emission limit from being exceeded or to minimize the period of time, during which the emission limit is exceeded. It can also be taken into account that certain countermeasures only become effective after a certain delay time.

[0044] The above-described steps also apply analogously to the control of the exhaust aftertreatment device 13. It was already mentioned above that the control of the exhaust aftertreatment device 13 has no or practically no power-reducing effects on the internal combustion engine 12. The exhaust aftertreatment device 13 therefore can initially be advantageously controlled such that the emission values of the emitted exhaust gases are reduced. The internal engine countermeasures may only be initiated once the control of the exhaust aftertreatment device 13 has been exhausted.

[0045] While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.