DE102021128148A1 - Method for operating an internal combustion engine in a vehicle, vehicle, computer program product and storage medium - Google Patents

Abstract

The present invention relates to a method for operating an internal combustion engine (10) in a vehicle (20), the internal combustion engine (10) comprising a combustion chamber (11), having the steps: moving the vehicle (20) in overrun mode, introducing fuel in the combustion chamber (11) during overrun, and burning the fuel in the combustion chamber (11) during overrun. The invention also relates to a vehicle (20) and a computer program product (13) for carrying out the method according to the invention, as well as a storage means (14) on which a computer program product (13) according to the invention is stored.

Description

The present invention relates to a method for operating an internal combustion engine in a vehicle, a vehicle for carrying out such a method, a computer program product and a storage medium.

The emission limit values, which have to be further reduced as exhaust gas legislation progresses, require measures that require both a reduction in raw emissions and an increase in efficiency and/or thermal management measures in exhaust gas aftertreatment. An effective measure to reduce raw NOx emissions is exhaust gas recirculation (EGR). The formation of NOx is reduced by the residual gas content in the combustion chamber of the internal combustion engine. After overrun, in which the internal combustion engine is towed without fuel input, the combustion chamber is completely filled with air. Depending on the duration of the overrun, there is also hardly any residual gas in the EGR path, so that when combustion resumes after overrun in a driving mode, only fresh air gets into the combustion chamber for a few work cycles. In conjunction with the high power requirement that often occurs after overrun, there are increased raw NOx emissions. At the same time, the exhaust gas temperatures drop significantly during overrun operation, so that depending on the duration of overrun operation, there is a visible temperature drop in the exhaust gas aftertreatment system or at least in some components of the exhaust gas aftertreatment system. This combination can lead to an increase in pollutant emissions at the tailpipe.

Various systems for reducing pollutant emissions are already known in the prior art. From the U.S. 10,967,866 B2 shows, for example, a drive train control system in which a fuel injection is carried out depending on the operating states of an exhaust gas aftertreatment system. Furthermore, it is known that, in order to reduce pollutant emissions, the torque gradient is reduced or, in electric hybrid vehicles, electric torque support is carried out. However, the known measures generally lead to losses in driving comfort or, in the case of hybrid vehicles, to an increased energy requirement.

The object of the present invention is to at least partially take account of the problems described above. In particular, it is the object of the present invention to reduce pollutant emissions during the operation of an internal combustion engine in a vehicle in the most efficient manner possible.

The above object is solved by the patent claims. In particular, the above object is achieved by the method according to claim 1, the vehicle according to claim 8, the computer program product according to claim 9 and the storage means according to claim 10. Further advantages of the invention result from the dependent claims, the description and the figures. Features that are described in connection with the method also apply, of course, in connection with the vehicle according to the invention, the computer program product according to the invention, the storage means according to the invention and vice versa, so that the disclosure of the individual aspects of the invention is and/or is always referred to mutually can.

• - Bewegen des Fahrzeugs in einem Schubbetrieb,
• - Einbringen von Kraftstoff in den Brennraum während des Schubbetriebs, und
• - Verbrennen des Kraftstoffs im Brennraum während des Schubbetriebs.

According to a first aspect of the present invention, a method for operating an internal combustion engine in a vehicle is proposed, the internal combustion engine comprising a combustion chamber. The procedure has the following steps:

• - moving the vehicle in overrun mode,
• - introducing fuel into the combustion chamber during overrun, and
• - Combustion of the fuel in the combustion chamber during overrun.

Within the scope of the present invention, it was recognized that the pollutant emissions can be reduced overall in a simple and reliable manner by introducing and burning a specific quantity of fuel in overrun mode. By introducing and burning the fuel in the overrun mode, the residual gas content in the exhaust gas or along an exhaust gas recirculation path and thus also in the combustion chamber can be increased, whereby a reduction in the raw NOx emissions can be achieved in the event of a subsequent power requirement. Tests within the scope of the present invention have also shown that the comparatively low NOx emissions generated during overrun can normally be completely reduced by an active SCR system. An increase in the total pollutant emissions can therefore be prevented. In addition, the procedure according to the invention also brings about a reduction in the emitted NOx emissions for the cold start phase.

Under the overrun or the movement of the vehicle in the overrun, a driving state of the vehicle can be understood in which there is no disconnection, for example when the clutch is not engaged, the internal combustion engine chine is dragged through the vehicle, i.e. kept rotating. In conventional vehicles, in particular in modern vehicles, the fuel supply is generally interrupted by an overrun cut-off. According to the invention, contrary to this procedure, a certain amount of fuel is introduced into the combustion chamber in a targeted manner during overrun operation and is then burned or burned as completely or at least partially as possible. If the vehicle is not parked directly after the overrun, a driving state that follows the overrun can be understood as an acceleration operation or a normal driving operation in which fuel is burned in the combustion chamber in a known manner. The amount of fuel that is introduced into the combustion chamber during overrun operation is preferably less than the amount of fuel that is introduced into the combustion chamber during driving operation. The introduction of the fuel can be understood to mean that fuel is actively or specifically introduced into the combustion chamber with a predefined and/or predefinable quantity. This is to be distinguished in particular from a possible unintentional and/or unavoidable entry of fuel at the start of the overrun or shortly after the end of a previous driving operation.

The combustion chamber of the internal combustion engine can have at least one combustion chamber and in particular three, four, six, or any number of combustion chambers. The internal combustion engine is preferably to be understood as a diesel engine or an internal combustion engine that can be operated with diesel. The vehicle is to be understood in particular as a motor vehicle such as a passenger car or a truck. However, the vehicle can also be understood to mean a rail vehicle, a watercraft or a robot.

According to one embodiment of the present invention, it is possible in a method that fuel is introduced into the combustion chamber in overrun mode with an overrun quantity in a range between 3 mg/stroke and 15 mg/stroke. The effects described above can thus be reliably achieved without having to fear disproportionately high fuel consumption. With a fuel quantity of up to 15 mg/stroke, pollutant emissions can also be reliably prevented, since the resulting NOx emissions can be reliably reduced by a generic exhaust gas aftertreatment system, for example an SCR catalytic converter. It has been found to be particularly preferable if fuel is introduced into the combustion chamber in overrun mode with an overrun quantity in a range between 6 mg/stroke and 12 mg/stroke.

In a method according to the invention, it is also possible for the fuel to be introduced into the combustion chamber and burned no earlier than 5 seconds before the start of driving operation of the vehicle following overrun operation, with the start of driving operation being determined as a function of predictive route data and/or vehicle data of the vehicle . It can thus be prevented that the fuel supply is carried out for an unnecessarily long time during the overrun operation and thus a correspondingly unnecessarily high fuel consumption is generated. Exhaust gas aftertreatment that is activated for an unnecessarily long time to reduce NOx emissions can also be avoided. The fact that the fuel is introduced and burned no earlier than 5 seconds before the start of a driving operation of the vehicle that follows the overrun mode can be understood to mean that the fuel is introduced and burned no earlier than 5 seconds before the start of a driving operation of the vehicle that follows the overrun mode. Accordingly, the fuel can also be introduced into the combustion chamber and burned, for example, only 4, 3, 2 or 1 second(s) before the start of the driving operation of the vehicle following the overrun operation. The predictive route data and/or vehicle data can include information about the flow of traffic, such as traffic light changes or traffic jam forecasts, a position determination as to whether the vehicle is leaving a town, a speed limit is about to be lifted, or cornering will soon be over, and/or driving behavior of the driver and/or the vehicle can be understood. The predictive route data and/or vehicle data can be determined by suitable sensors and/or an associated computing unit.

It can be of further advantage if, in a method according to the present invention, the fuel is introduced into the combustion chamber and burned during overrun depending on predictive route data and/or vehicle data of the vehicle. Here, too, regardless of the exact transition from overrun mode to driving mode, a general and therefore possibly unnecessarily long introduction and combustion of the fuel can be prevented.

In addition, it is possible that, in a method according to the invention, mechanical energy that is generated by burning the fuel in overrun mode is converted into electrical energy by an energy converter. The method can thus be carried out in a particularly energy-efficient manner. Energy generated by the otherwise non-existent combustion during overrun can be stored in the form of electrical energy and used for other processes in the vehicle. The energy converter can have a generator, in particular a belt starter generator, for converting the mechanical energy into electrical energy. The conversion of the mechanical energy into electrical energy is preferably carried out in such a way that a thrust torque generated there is kept as constant as possible during the overrun operation.

According to an advantageous embodiment variant of the present invention, it is possible for an exhaust gas aftertreatment system of the vehicle to be heated by means of the electrical energy. For example, an electrically heatable catalytic converter can be heated.

Furthermore, it is possible that in a method according to the invention, a battery of the vehicle is charged by means of the electrical energy, the battery being understood to mean in particular a drive battery or a high-voltage battery. Other electrical energy stores such as a starter battery can of course also be charged.

According to a further aspect of the present invention, a vehicle with an internal combustion engine is proposed, which is configured and designed to carry out a method according to one of the preceding claims. That is, the vehicle is configured and designed to actuate functional components of the vehicle to cause the introduction and combustion of the fuel into the combustion chamber in the overrun mode. For this purpose, the vehicle can have a suitable sensor system and computing units, for example as part of a control unit of the vehicle. The vehicle according to the invention thus brings with it the same advantages as have been described in detail with reference to the method according to the invention.

According to a further aspect of the invention, a computer program product is proposed which includes instructions which cause a method according to the invention to be carried out in the vehicle described above. A further aspect of the invention relates to a computer-readable storage medium on which such a computer program product is stored. The computer program product and the storage means thus also bring with them the advantages described above. The storage means is preferably designed in the form of a non-volatile storage means.

The computer program product may be implemented as computer-readable instruction code in any suitable programming language and/or machine language, such as JAVA, C++, C#, and/or Python. The computer program product can be stored on a computer-readable storage medium such as a data disk, a removable drive, a volatile or non-volatile memory, or a built-in memory/processor. The instruction code may program a computer or other programmable device, such as a vehicle's controller, to perform the desired functions. Furthermore, the computer program product can be and/or be provided on a network such as the Internet, from which it can be downloaded by a user when required. The computer program product can be and/or be implemented both by means of software and by means of one or more special electronic circuits, ie in hardware or in any hybrid form, ie by means of software components and hardware components.

Further measures improving the invention result from the following description of various exemplary embodiments of the invention, which are shown schematically in the figures. All of the features and/or advantages resulting from the claims, the description or the figures, including structural details and spatial arrangements, can be essential to the invention both on their own and in the various combinations.

• 1 ein Fahrzeug gemäß einer Ausführungsform der Erfindung,
• 2 ein Speichermittel mit einem darauf gespeicherten Computerprogrammprodukt gemäß einer Ausführungsform der Erfindung, und
• 3 ein Betriebsdiagramm zum Erläutern des erfindungsgemäßen Verfahrens.

They each show schematically:

• 1 a vehicle according to an embodiment of the invention,
• 2 a storage means having stored thereon a computer program product according to an embodiment of the invention, and
• 3 an operating diagram for explaining the method according to the invention.

Elements with the same function and mode of operation are each provided with the same reference symbols in the figures.

1 shows a vehicle 20 in the form of a passenger car. More precisely, the car is designed as a hybrid electric vehicle with an internal combustion engine 10 and an electric motor 18 . Internal combustion engine 10 has a combustion chamber 11 . Combustion chamber 11 includes multiple combustion chambers. The vehicle 20 also has a control device 16 for controlling the driving operation of the vehicle 20 . In addition, the vehicle has a battery 15 in the form of a high-voltage battery and an exhaust gas aftertreatment system 12 . In particular, the battery 15 is configured to power the electric motor 18 . The exhaust aftertreatment system 12 has an electrically heatable SCR catalytic converter or a catalytic converter with a heatable SCR line. In addition, vehicle 20 has an energy converter 17 in the form of a generator, via which mechanical energy generated by internal combustion engine 10 can be converted into electrical energy. The battery 15 can be charged by means of the converted electrical energy. A computer program product 13 is installed in the control unit 16, by means of which the vehicle 20 or functional components in the vehicle 20 and in the environment of the vehicle 20 for executing a later with reference to 3 described method can be controlled. 2 shows a computer-readable, non-volatile and portable storage medium 14, on which such a computer program product 13 is also stored.

With reference to the in 3 The flow chart shown then describes a method for operating the internal combustion engine 10 of FIG 1 shown vehicle 20 explained. In particular, the core aspects of the method are first explained. In a first step S1, the vehicle is initially moved or driven in overrun mode. In a second step S2, fuel is introduced into combustion chamber 11 during overrun. In a subsequent third step S3, the fuel in the combustion chamber 11 is burned.

In addition to the illustrated embodiments, the invention permits further design principles. That is, the invention should not be considered limited to the exemplary embodiments explained with reference to the figures. In one method, the fuel can be introduced into combustion chamber 11 and burned no earlier than 5 seconds before the start of driving operation of vehicle 20 that follows overrun operation, with the start of driving operation being determined as a function of predictive route data and/or vehicle data of vehicle 20. In the overrun mode, fuel is introduced into the combustion chamber 11 with an overrun quantity in a range between 3 mg/stroke and 15 mg/stroke and in particular in a range between 6 mg/stroke and 12 mg/stroke. Mechanical energy, which is generated by burning the fuel in the overrun mode, can be converted into electrical energy by the energy converter 17 . The exhaust gas aftertreatment system 12 of the vehicle 20, in particular the electrically heatable SCR catalytic converter, can be heated by means of the electrical energy. In addition, the battery 15 of the vehicle 20 can be charged by means of the electrical energy.

The method can be carried out at least partially not only in the hybrid electric vehicle shown, but of course also in a vehicle without an electric motor 18 and without a battery 15 or high-voltage battery.

Reference List

10

internal combustion engine

11

combustion chamber

12

exhaust aftertreatment system

13

computer program product

14

storage means

15

battery

16

control unit

17

energy converter

18

electric motor

20

vehicle

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

• US 10967866 B2 [0003]

Claims (10)

Method for operating an internal combustion engine (10) in a vehicle (20), the internal combustion engine (10) comprising a combustion chamber (11), having the steps: - Moving the vehicle (20) in an overrun mode, - Introducing fuel into the combustion chamber (11) during overrun, and - Combustion of the fuel in the combustion chamber (11) during overrun. procedure after claim 1 , characterized in that in the overrun mode, fuel is introduced into the combustion chamber (11) with an overrun quantity in a range between 3 mg/stroke and 15 mg/stroke. Method according to one of the preceding claims, characterized in that the fuel is introduced into the combustion chamber (11) and burned no earlier than 5 seconds before the start of driving operation of the vehicle (20) that follows overrun operation, the start of driving operation depending on predictive route data and / or vehicle data of the vehicle (20) is determined. Method according to one of the preceding claims, characterized in that the fuel is introduced into the combustion chamber (11) and burned during the overrun depending on predictive route data and/or vehicle data of the vehicle (20). Method according to one of the preceding claims, characterized in that mechanical energy, which is generated by burning the fuel in overrun mode, is converted into electrical energy by an energy converter (17). procedure after claim 5 , characterized in that an exhaust aftertreatment system (12) of the vehicle (20) is heated by means of the electrical energy. Procedure according to one of Claims 5 until 6 , characterized in that a battery (15) of the vehicle (20) is charged by means of the electrical energy. Vehicle (20) with an internal combustion engine (10), which is configured and designed to carry out a method according to one of the preceding claims. Computer program product (13), comprising instructions that cause in the vehicle (20) after claim 8 a method according to one of Claims 1 until 7 is carried out. Computer-readable storage means (14) with a computer program product (13) stored thereon claim 9 .

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