DE102020100539A1 - Method for operating a motor vehicle with a diesel hybrid drive and diesel hybrid drive - Google Patents

Abstract

The invention relates to a method for operating a motor vehicle with a diesel hydride drive from an internal combustion engine (10) and an electric drive motor (76). The internal combustion engine (10) can be coupled to a generator (72) in order to charge a battery (74) to supply the electric drive motor (76). The internal combustion engine (10) is connected by its outlet (18) to an exhaust system (40) in which several exhaust gas aftertreatment components (46, 48, 50) are arranged. The method comprises the following steps: determining a state of charge (SOC) of the battery (76), heating the exhaust gas aftertreatment components (46, 48, 50) when the battery (74) falls below a threshold value (SOCmin) for the state of charge, the internal combustion engine (10) is coupled to the generator (72), the internal combustion engine (10) being operated with a quasi-stationary operating point which is ideal with regard to the raw emissions and / or the heating behavior of the exhaust gas aftertreatment components, as long as the exhaust gas aftertreatment components (46, 48, 50) have not yet reached their operating temperature (TLO), charging the battery (74) when the exhaust gas aftertreatment components (46, 48, 50) have reached their operating temperature (TLO). The invention also relates to a diesel hybrid drive for implementation such a procedure.

Description

The invention relates to a method for operating a diesel hybrid drive and a diesel hybrid drive for a motor vehicle according to the preamble of the independent claims.

The current exhaust gas legislation, and one that will become increasingly strict in the future, place high demands on the engine-related raw emissions and the exhaust gas aftertreatment of internal combustion engines. The demands for a further decrease in consumption and the further tightening of the exhaust gas standards with regard to the permissible nitrogen oxide emissions represent a challenge for the engine developers. In gasoline engines, the exhaust gas purification takes place in the known manner via a three-way catalytic converter and a three-way catalytic converter - and further downstream catalysts. Exhaust aftertreatment systems are currently used in diesel engines which have an oxidation catalytic converter or a NO _x storage catalytic converter, a catalytic converter for the selective catalytic reduction of nitrogen oxides (SCR catalytic converter) and a particle filter for separating soot particles and, if necessary, further catalytic converters. In order to meet the high requirements for minimal nitrogen oxide emissions, exhaust gas aftertreatment systems are known which have two SCR catalytic converters connected in series, each of the SCR catalytic converters being preceded by a metering element for metering in a reducing agent. A synthetic, aqueous urea solution is preferably used as the reducing agent, which is mixed with the hot exhaust gas flow in a mixing device upstream of the SCR catalytic converter. As a result of this mixing, the aqueous urea solution is heated, the aqueous urea solution releasing ammonia in the exhaust gas duct. A commercially available, aqueous urea solution generally consists of 32.5% urea and 67.5% water.

In order to reduce the carbon dioxide emissions of a motor vehicle, hybrid drives are known which have an internal combustion engine and an electric drive motor. It is possible to operate the motor vehicle purely electrically and thus locally emission-free. Since the system performance of the internal combustion engine and the electric drive motor determines the driving performance of the motor vehicle, a smaller and less powerful internal combustion engine can be used, which means that consumption can be reduced even when the vehicle is driven exclusively by the internal combustion engine.

If the battery falls below a specified, minimum charge status in electric driving mode, which makes it necessary for the internal combustion engine to be started in the foreseeable future, it is known to heat up the exhaust system using an electrically heated catalytic converter before starting the internal combustion engine in order to achieve a to enable efficient conversion of the pollutants in the exhaust gas flow of the internal combustion engine.

US 2011/0 078 999 A1 discloses a hybrid drive train for a motor vehicle with an electrically heatable catalytic converter in the exhaust system of an internal combustion engine. The electrically heated catalytic converter is heated up when the charge status falls below a defined threshold value for the battery of the electric drive motor of the hybrid drive. The threshold value is selected in such a way that sufficient energy remains in the battery to heat the catalytic converter to its activation temperature before the internal combustion engine is started. A battery parameter and a charge status of the battery are recorded and the electrically heated catalytic converter in the exhaust system is activated depending on the charge status of the battery.

A method for heating an electrically heatable catalytic converter in the exhaust system of a motor vehicle, which is driven by a hybrid drive with an internal combustion engine and an electric drive motor, is known from US 2013/0 035 845 A1. A further catalytic converter is arranged downstream of the electrically heatable catalytic converter in the exhaust system of the internal combustion engine. The electrically heated catalytic converter is heated up before the internal combustion engine is started and a statement is made as to whether the power requirement of the internal combustion engine from its start is higher than a threshold power requirement, the internal combustion engine being rotated by the electric drive motor and the heat from the electrically heated catalytic converter to the second catalyst is transferred when the expected power requirement to the internal combustion engine from the start of the internal combustion engine is above the threshold power requirement.

US 2003/0 172 643 A1 discloses a method for operating a hybrid vehicle with an internal combustion engine and an electric drive motor, the battery of the electric drive motor being charged by the internal combustion engine when the remaining charge of the drive battery falls below a defined charge status. The internal combustion engine and / or a catalyst in the exhaust system of the internal combustion engine are heated up before the internal combustion engine is started, so that the catalyst can efficiently convert pollutants from the start of the internal combustion engine. The battery is only charged when the internal combustion engine is running and an exhaust aftertreatment component are preheated.

The invention is now based on the object of minimizing the emissions of the internal combustion engine when charging the battery or when generating electricity directly for the electric machine.

• - Ermitteln eines Ladezustands (SOC) der Batterie,
• - Aufheizen der Abgasnachbehandlungskomponenten, wenn die Batterie einen Schwellenwert für den Ladezustand unterschreitet, wobei
• - der Verbrennungsmotor mit einem in Bezug auf die Rohemissionen und/oder das Aufheizverhalten der Abgasnachbehandlung idealen, quasi-stationären Betriebspunkt betrieben wird, solange die Abgasnachbehandlungskomponenten noch nicht ihre Betriebstemperatur erreicht haben, und
• - Laden der Batterie, wenn die Abgasnachbehandlungskomponenten ihre jeweilige Betriebstemperatur erreicht haben.

According to the invention, this object is achieved by a method for operating a motor vehicle with a diesel hydride drive, comprising an internal combustion engine, an electric drive motor, a battery and a generator, wherein the internal combustion engine can be coupled to the generator in order to charge the battery Drive motor is supplied with power by the battery or directly from the generator, the internal combustion engine being connected with its outlet to an exhaust system in which an oxidation catalytic converter, an SCR catalytic converter and a particle filter are arranged, comprising the following steps:

• - Determination of the state of charge (SOC) of the battery,
• - Heating the exhaust gas aftertreatment components when the battery falls below a threshold value for the state of charge, wherein
• - The internal combustion engine is operated at a quasi-stationary operating point that is ideal with regard to the raw emissions and / or the heating behavior of the exhaust gas aftertreatment, as long as the exhaust gas aftertreatment components have not yet reached their operating temperature, and
• - Charging the battery when the exhaust aftertreatment components have reached their respective operating temperature.

A method according to the invention makes it possible to reduce the emissions in the case of a diesel hybrid drive and, in particular, to reduce the emissions when the internal combustion engine is switched on. Due to the quasi-stationary operating point when the exhaust gas aftertreatment components are heated up, the raw emissions of the internal combustion engine can be minimized. Dynamic load requirements for the diesel hybrid system can be met by the remaining charge of the battery, so that corresponding load changes do not lead to an increase in emissions even immediately after the motor vehicle has been started. The minimum charge status of the battery is set in such a way that a maximum power demand on the battery is possible for at least 30 s, preferably for at least 60 s, particularly preferably for 3 min. The electric drive motor can thus both meet the load requirements and bridge a sufficient operating period of the motor vehicle until the exhaust gas aftertreatment components have reached their respective operating temperature and low-emission operation of the internal combustion engine is possible. In this context, an operating temperature is to be understood as a light-off temperature of an oxidation catalytic converter or an SCR catalytic converter.

The features listed in the dependent claims allow advantageous improvements and non-trivial further developments of the method mentioned in the independent claim for operating a motor vehicle with a diesel hybrid drive.

In a preferred embodiment of the invention it is provided that the power of the internal combustion engine is limited as long as the exhaust gas aftertreatment components have not yet reached their operating temperature. This can prevent a dynamic load requirement on the internal combustion engine from leading to a sharp increase in the raw emissions, which in this operating phase cannot yet be sufficiently converted by the exhaust gas aftertreatment components and would otherwise be emitted to the environment.

In a preferred embodiment variant of the method it is provided that the limitation of the power of the internal combustion engine is lifted as soon as the exhaust gas aftertreatment components have reached their operating temperature. Once the exhaust gas aftertreatment components, in particular an oxidation catalytic converter and an SCR catalytic converter, have reached their operating temperature, the pollutants in the exhaust gas flow of the internal combustion engine can be efficiently converted into unlimited exhaust gas components, so that the full power of the internal combustion engine can be released.

In a further preferred embodiment of the invention it is provided that in the event of a dynamic load requirement during the quasi-stationary operation of the internal combustion engine, the additional power is made available by the battery. In order to avoid an increase in emissions, dynamic peaks can be covered by an additional power supply from the battery, so that the internal combustion engine can be operated at an emission-minimal, quasi-stationary operating point until the operating temperature is reached.

In an advantageous embodiment of the method, it is provided that when a motor vehicle is cold started with such a diesel hybrid drive, the drive is carried out exclusively by the electric drive motor. With purely electrical operation, no emissions are emitted locally. At least parts of the drive train can heat up, so that the friction at a later start of the internal combustion engine is minimized. This enables the internal combustion engine to be switched on with lower emissions.

Another improvement of the method provides that when the particle filter is regenerated, the particle filter is heated by shifting the load point of the internal combustion engine, with the generator applying an additional load in order to increase the exhaust gas temperature. In order to heat the particle filter to its regeneration temperature, internal engine measures are necessary in the case of low-load operation of the internal combustion engine, which reduce the efficiency of the internal combustion engine and can lead to an increase in raw emissions. By coupling the generator to the internal combustion engine, an additional load can be generated which, even in a driving situation which in itself only places a low demand on the internal combustion engine, demands a correspondingly high engine output, which favors the heating of the particle filter. The internal engine heating measures can be reduced accordingly, which reduces the fuel consumption of the internal combustion engine and the raw emissions.

Another aspect of the invention relates to a diesel hybrid drive comprising an internal combustion engine, an electric drive motor, a battery and a generator, the internal combustion engine being able to be coupled to the generator in order to charge the battery, the electric drive motor being powered by the battery or directly the generator is supplied with electricity, the outlet of the internal combustion engine being connected to an exhaust system in which an oxidation catalytic converter, an SCR catalytic converter and a particle filter are arranged, as well as to a control unit which is set up to carry out a method according to the invention if a machine-readable program code is executed by the control unit. Such a diesel hybrid drive can reduce the emissions of a motor vehicle. Both the carbon dioxide emissions and the emissions of unburned hydrocarbons, carbon monoxide and nitrogen oxides can be minimized.

In a preferred embodiment of the diesel hybrid drive, it is provided that the internal combustion engine is charged by means of an exhaust gas turbocharger, the internal combustion engine having a high pressure exhaust gas recirculation system which has an exhaust gas duct of the exhaust system downstream of an outlet of the internal combustion engine and upstream of a turbine of the exhaust gas turbocharger with an intake duct of an air supply system of the internal combustion engine downstream of a compressor of the exhaust gas turbocharger and upstream of an inlet of the internal combustion engine, the high pressure exhaust gas recirculation having an exhaust gas recirculation duct in which an exhaust gas recirculation cooler line and an exhaust gas recirculation valve are arranged. In this case, the raw emissions of the internal combustion engine, in particular the nitrogen oxide emissions, can be reduced by a cooled exhaust gas recirculation via the high pressure exhaust gas recirculation.

In an advantageous embodiment of the exhaust system of the diesel hybrid drive, it is provided that an oxidation catalytic converter is arranged in the exhaust system in the flow direction of an exhaust gas flow through an exhaust gas duct of the exhaust system, an SCR catalytic converter downstream of the oxidation catalytic converter and a particle filter downstream of the SCR catalytic converter. By using an SCR catalytic converter and a particulate filter instead of a particulate filter with an SCR coating, both exhaust gas aftertreatment components can be optimally matched to their respective function and, with regard to this function, achieve a higher degree of efficiency than a particulate filter with an SCR coating. This reduces the exhaust gas back pressure, for example, which reduces the fuel consumption of the internal combustion engine. The use of a second SCR catalytic converter can be dispensed with, since the internal combustion engine is operated in a restricted map range and the usual spread of the exhaust gas temperature is therefore lower.

In an advantageous further development of the diesel hybrid drive, it is provided that downstream of a particle filter a low-pressure exhaust gas recirculation branches off from an exhaust duct of the exhaust system, which connects the exhaust system downstream of a turbine of the exhaust gas turbocharger with the intake duct of the air supply system, downstream of a throttle valve and upstream of a compressor of the exhaust gas turbocharger. The exhaust gas recirculation rate can be increased further by means of a low-pressure exhaust gas recirculation, as a result of which the raw nitrogen oxide emissions of the internal combustion engine can be further reduced.

The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless stated otherwise in the individual case.

• 1 ein Kraftfahrzeug mit einem Diesel-Hybrid-Antrieb, bei welchem der Verbrennungsmotor mit einem Generator koppelbar und mit einer Abgasanlage verbunden ist;
• 2 ein Ausführungsbeispiel für einen Verbrennungsmotor mit einem Luftversorgungssystem und einer Abgasanlage für einen Diesel-Hybrid-Antrieb;
• 3 ein weiteres Ausführungsbeispiel für einen Verbrennungsmotor mit einem Luftversorgungssystem und einer Abgasanlage für einen Diesel-Hybrid-Antrieb; und
• 4 ein Ablaufdiagramm zur Durchführung eines erfindungsgemäßen Verfahrens zum Betreiben eines Kraftfahrzeugs mit einem Diesel-Hybrid-Antrieb.

The invention is explained below in exemplary embodiments with reference to the accompanying drawings. The same components or components with the same function are identified by the same reference numbers in the different figures. Show it:

• 1 a motor vehicle with a diesel hybrid drive, in which the internal combustion engine can be coupled to a generator and is connected to an exhaust system;
• 2 an embodiment for an internal combustion engine with an air supply system and an exhaust system for a diesel hybrid drive;
• 3 a further embodiment for an internal combustion engine with an air supply system and an exhaust system for a diesel hybrid drive; and
• 4th a flowchart for performing a method according to the invention for operating a motor vehicle with a diesel hybrid drive.

1 shows an embodiment for a motor vehicle 1 with a diesel hybrid drive. The diesel hybrid drive comprises an internal combustion engine 10 , a generator 72 , a battery 74 and an electric drive motor 76 . The internal combustion engine 10 has several combustion chambers 12th on each of which has a fuel injector 14th for injecting a fuel into the respective combustion chamber 12th is arranged. The internal combustion engine 10 has an outlet 18th on what the internal combustion engine 10 with an exhaust system 40 connected is.

The internal combustion engine 10 is about a clutch 84 with a generator 72 connectable to the battery 74 of the diesel hybrid drive or to supply the electric machine directly with electricity. The diesel hybrid drive can also be used as a plug-in hybrid 82 run so that the battery 74 can additionally be charged via a vehicle-external charging mechanism, in particular a charging cable. Alternatively it is possible that the battery 74 is discharged by an inductive charging station. The battery 74 is with an electric drive motor 76 connected, which is the wheels of a drive axle 78 of the motor vehicle 1 drives. The electric drive motor 76 and the internal combustion engine 10 can use the same axle of the motor vehicle 1 drive. Alternatively, the internal combustion engine 10 and the electric drive motor 76 also each drive an axle of the motor vehicle, whereby an all-wheel drive can be formed in a simple manner. In the main version, it is assumed that the internal combustion engine only works as a generator. The diesel hybrid drive is via a control unit 80 controllable, which in particular the connection and disconnection of the internal combustion engine 10 or the electric drive motor 76 controls.

In 2 Figure 3 is a schematic representation of an internal combustion engine 10 with an air supply system 20th and an exhaust system 40 disclosed for such a diesel hybrid drive. The internal combustion engine 10 is in this embodiment a direct injection diesel engine and has several combustion chambers 12th on. At the combustion chambers 12th is a fuel injector each 14th for injecting a fuel into the respective combustion chamber 12th arranged. The internal combustion engine 10 is with his inlet 16 with an air supply system 20th and with its outlet 18th with an exhaust system 40 connected. At the combustion chambers 12th inlet valves and outlet valves are arranged, with which a fluidic connection from the air supply system 20th to the combustion chambers 12th or from the combustion chambers 12th to the exhaust system 40 can be opened or closed.

The air supply system 20th includes an intake duct 22nd , in which in the direction of flow of fresh air through the intake duct 22nd a throttle 24 and downstream of the throttle 24 a compressor 28 of an exhaust gas turbocharger 26th are arranged. Downstream of the compressor 28 and upstream of the inlet 16 opens an exhaust gas recirculation line 32 a high pressure exhaust gas recirculation 30th at a confluence 38 in the intake duct 22nd .

The exhaust system 40 includes an exhaust duct 42 , in which in the flow direction of an exhaust gas of the internal combustion engine 10 through the exhaust duct 42 a turbine 44 of the exhaust gas turbocharger 26th is arranged, which the compressor 28 in the air supply system 20th drives over a shaft. The exhaust gas turbocharger 26th is preferably used as an exhaust gas turbocharger 26th designed with variable turbine geometry. To do this are a turbine wheel of the turbine 44 adjustable guide vanes are connected upstream, via which the flow of the exhaust gas onto the blades of the turbine 44 can be varied. Downstream of the turbine 44 are several exhaust aftertreatment components 46 , 48 , 50 intended. This is immediately downstream of the turbine 44 the first component of exhaust gas aftertreatment is an oxidation catalytic converter 46 , downstream of the oxidation catalyst 46 an SCR catalytic converter 48 and downstream of the SCR catalyst 48 a particulate filter 50 arranged. Downstream of the oxidation catalyst 46 and upstream of the SCR catalyst 48 is on the exhaust duct 42 a metering valve 52 arranged, with which a reducing agent, in particular an aqueous urea solution, into the exhaust duct 42 can be introduced. Downstream of the metering valve 52 and upstream of the SCR catalyst 48 can be an exhaust mixer 54 be arranged to the mixing of the reducing agent with the exhaust gas flow of the internal combustion engine 10 to improve.

The internal combustion engine 10 includes high pressure exhaust gas recirculation 30th with an exhaust gas recirculation line 32 , in which a Exhaust gas recirculation valve 34 and an exhaust gas recirculation cooler 36 are arranged. Via the high pressure exhaust gas recirculation 30th can be an exhaust gas flow from the internal combustion engine 10 from the exhaust duct 42 downstream of the outlet 18th and upstream of the turbine 44 in the intake duct 22nd downstream of the compressor 28 and upstream of the inlet 16 to be led back. The exhaust gas recirculation line branches off for this purpose 32 at a branch 58 downstream of the outlet 18th and upstream of the turbine 44 from the exhaust duct 42 and opens at a confluence 38 downstream of the compressor 28 and upstream of the inlet 16 in the intake duct. The oxidation catalyst 46 can one in 3 illustrated electrically heatable catalyst 56 include, which is on the inlet side of the oxidation catalytic converter 46 is arranged or the oxidation catalyst 46 is connected upstream in the direction of flow.

During the operation of the internal combustion engine 10 is a partial flow of the exhaust gas via the high pressure exhaust gas recirculation 30th in the intake duct 22nd returned. This increases the mass flow rate through the exhaust gas aftertreatment components 46 , 48 , 50 Exhaust gas to be post-treated is kept as low as possible. The oxidation catalytic converter is the first catalytically active exhaust gas aftertreatment component to oxidize 46 Carbon monoxide (CO) and unburned hydrocarbons (HC) to carbon dioxide. This reduces the negative influence of the unburned hydrocarbon on the SCR function and the pollutants are effectively and efficiently reduced. The SCR function and the particle filter function are implemented in two separate components. Here is the SCR catalytic converter 48 the particle filter 50 upstream in the direction of flow. This means that there are no negative effects on the SCR function through regeneration of the particulate filter 50 . Furthermore, the efficiency of the SCR catalytic converter 48 can be increased, since a larger catalytically active surface and / or a lower thermal mass can be realized. The one for regeneration of the particle filter 50 required temperature can be achieved by coupling the generator 72 about the clutch 84 and an associated setting of an optimal load point of the internal combustion engine 10 to heat up the particle filter 50 respectively. Thanks to the electrically heated catalytic converter 56 can heat up the oxidation catalyst 46 after starting the internal combustion engine 10 be accelerated. Alternatively, the exhaust gas aftertreatment components can be preheated 46 , 48 , 50 in a purely electric driving mode of the motor vehicle 1 take place before the internal combustion engine 10 is switched on.

In 3 is another embodiment for an internal combustion engine 10 shown for a diesel hybrid drive. With essentially the same structure as to 2 running, the internal combustion engine 10 In addition, a low-pressure exhaust gas recirculation 60 on which the exhaust duct 42 downstream of the particulate filter 50 with the intake duct 42 downstream of the throttle 24 and upstream of the compressor 28 connects. The low-pressure exhaust gas recirculation 60 has an exhaust gas recirculation line 64 on which at a branch 62 from the exhaust duct 42 branches off and at a confluence 70 in the intake duct 22nd joins. In the exhaust gas recirculation line 64 are an exhaust gas recirculation cooler 66 and an exhaust gas recirculation valve 68 arranged. The oxidation catalyst 46 can use an electrically heated catalytic converter 56 include, which is on the inlet side of the oxidation catalytic converter 46 is arranged or the oxidation catalyst 46 is connected upstream in the direction of flow.

Through the low pressure exhaust gas recirculation 60 can be the exhaust gas recirculation rate for the internal combustion engine 10 can be further increased. In this way, the raw nitrogen oxide emissions can be reduced further. There is no need for a second SCR system because the internal combustion engine 10 in a diesel hybrid drive is operated in a restricted map area and thus the exhaust gas temperatures are in a range in which an efficient conversion of the nitrogen oxide emissions by the SCR catalytic converter 48 is guaranteed.

In 4th FIG. 3 is a flow chart for performing a method for operating a motor vehicle 1 shown with a diesel hybrid drive. In a method step <100>, the charging status SOC of the battery becomes 74 checked and compared with a threshold value SOC _min for a minimum permissible charge status. The threshold value SOC _min is set in such a way that a sufficient battery reserve is always available in order to heat the exhaust gas aftertreatment components with optimum emissions 46 , 48 , 50 to be able to perform. The motor vehicle is then started 1 when the internal combustion engine is cold 10 in a method step <110> initially by a purely electric drive via the electric drive motor 76 . Alternatively, the internal combustion engine 10 also exclusively for the power supply of the electric drive motor 76 serve without a mechanical connection to the drive train of the motor vehicle 1 to have.

If the battery falls below 74 when the motor vehicle is being driven electrically 1 this threshold SOC _min , it is necessary to control the internal combustion engine 10 to switch on. The internal combustion engine 10 is used to heat up the exhaust system 40 started in a method step <120> and via the clutch 84 with the generator 72 connected. The internal combustion engine remains 10 initially from the drive train of the motor vehicle 1 separated so that the drive of the motor vehicle 1 continues to be purely electrical. About the generator 72 becomes a quasi-stationary load point of the internal combustion engine in a method step <130> 10 which is optimal with regard to the raw emissions of the internal combustion engine 10 and heating up the exhaust aftertreatment components 46 , 48 , 50 in the exhaust system 40 is.

Reaching the oxidation catalyst 46 and the SCR catalytic converter 48 each their light-off temperature T _LO , from which an efficient conversion of the pollutants in the exhaust gas flow of the internal combustion engine 10 is possible, an operating point of the internal combustion engine is set in a method step <140> 10 approached to which the battery 74 of the diesel hybrid drive by the generator 72 is charged or the electric drive motor 76 by the generator 72 can be operated. Have the exhaust system 40 or in the exhaust system 40 arranged exhaust aftertreatment components 46 , 48 , 50 reaches its operating temperature T _B and the battery 74 When a defined minimum charge is reached, the diesel hybrid drive can be fully enabled in a method step <150>, with the drive optionally being provided by the internal combustion engine 10 , by the electric drive motor 76 or both engines 10 , 76 he follows.

Should the battery 74 have fallen below the threshold value SOC _min , so that a purely electric driving operation is not possible or a defined power reserve is undershot, the power of the diesel hybrid drive is limited and the motor vehicle is driven by the internal combustion engine 10 that is about the generator 72 generates the necessary electricity. The maximum power during this limitation depends on the optimal operating point of the internal combustion engine 10 with regard to its raw emissions and the heating behavior of the exhaust aftertreatment components 46 , 48 , 50 . This limitation is lifted as soon as the exhaust aftertreatment components 46 , 48 , 50 have reached their operating temperature T _B or the respective light-off temperature T _LO ).

List of reference symbols

1

Motor vehicle

10

Internal combustion engine

12th

Combustion chamber

14th

Fuel injector

16

inlet

18th

Outlet

20th

Air supply system

22nd

Intake duct

24

throttle

26th

Exhaust gas turbocharger

28

compressor

30th

High pressure exhaust gas recirculation

32

Exhaust gas recirculation line

34

Exhaust gas recirculation valve

36

Exhaust gas recirculation cooler

38

Confluence

40

Exhaust system

42

Exhaust duct

44

turbine

46

Oxidation catalyst

48

SCR catalytic converter

50

Particle filter

52

Dosing valve

54

Exhaust mixer

56

electrically heated catalytic converter

58

first branch

60

Low pressure exhaust gas recirculation

62

second branch

64

Exhaust gas recirculation line

66

Exhaust gas recirculation cooler

68

Exhaust gas recirculation valve

70

Confluence

72

generator

74

battery

76

electric drive motor

78

Drive axle

80

Control unit

82

Plug-in hybrid

84

coupling

Claims (10)

A method for operating a motor vehicle (1) with a diesel hydride drive, comprising an internal combustion engine (10), an electric drive motor (76), a battery (74) and a generator (72), the internal combustion engine (10) being connected to the Generator (72) can be coupled in order to charge the battery (74), the electric drive motor (76) being supplied with power by the battery (74), the internal combustion engine (10) having its outlet (18) with an exhaust system (40 ) is connected, in which an oxidation catalytic converter (46), an SCR catalytic converter (48) and a particle filter (50) are arranged, comprising the following steps: Determination of a state of charge (SOC) of the battery (76), heating of the exhaust gas aftertreatment components (46, 48, 50) when the battery (74) _{falls below a threshold value (SOC min} ) for the state of charge, the internal combustion engine (10) to the generator (72) is coupled, - the internal combustion engine (10) is operated with an ideal, quasi-stationary operating point with regard to the raw emissions and / or the heating behavior of the exhaust gas aftertreatment components (46, 48, 50) as long as the exhaust gas aftertreatment components (46, 48, 50) have not yet reached their operating temperature (T _LO ), - charging the battery (74) when the exhaust gas aftertreatment components (46, 48, 50) have reached their operating temperature (T _LO ). Procedure according to Claim 1 , characterized in that the power of the internal combustion engine (10) is limited as long as the exhaust gas aftertreatment components (46, 48, 50) have not yet reached their operating temperature (T _LO ). Procedure according to Claim 2 , characterized in that the limitation of the power of the internal combustion engine (10) is lifted as soon as the exhaust gas aftertreatment components (46, 48, 50) have reached their operating temperature. Method according to one of the Claims 1 to 3 that in the event of a dynamic load requirement during the quasi-stationary operation of the internal combustion engine (10), the additional power is made available by the battery (74). Method according to one of the Claims 1 to 4th , characterized in that during a cold start of a motor vehicle (1) with such a diesel hybrid drive, the drive is carried out exclusively by the electric drive motor (76). Method according to one of the Claims 1 to 5 , characterized in that when the particle filter (50) is regenerated, the particle filter (50) is heated by shifting the load point of the internal combustion engine (10), with the generator (72) applying an additional load to increase the exhaust gas temperature (T _EG ) to increase. Diesel hybrid drive (10, 76) comprising an internal combustion engine (10) and an electric drive motor (76) as well as a battery (74) and a generator (72), wherein the internal combustion engine (10) can be coupled to the generator (72) to charge the battery (74), the electric drive motor (76) being supplied with power by the battery (74), the internal combustion engine (10) having its outlet (18) connected to an exhaust system (40) in which an oxidation catalytic converter (46), an SCR catalytic converter (48) and a particle filter (50) are arranged, and with a control unit (80) which is set up to implement a method according to one of the Claims 1 to 6th to be carried out when a machine-readable program code is executed by the control device (80). Diesel hybrid drive after Claim 7 , characterized in that the internal combustion engine (10) is charged by means of an exhaust gas turbocharger (26), the internal combustion engine (10) having a high-pressure exhaust gas recirculation (30), which has an exhaust gas duct (42) of the exhaust system (40) downstream of an outlet (18 ) of the internal combustion engine (10) and upstream of a turbine (44) of the exhaust gas turbocharger (26) with an intake duct (22) of an air supply system (20) of the internal combustion engine (10) downstream of a compressor (28) of the exhaust gas turbocharger (26) and upstream of an inlet ( 16) of the internal combustion engine (10), the high-pressure exhaust gas recirculation (30) having an exhaust gas recirculation line (32) in which an exhaust gas recirculation cooler (36) and an exhaust gas recirculation valve (34) are arranged. Diesel hybrid drive after Claim 7 or 8th , characterized in that in the exhaust system (40) in the flow direction of an exhaust gas flow through an exhaust duct (42) of the exhaust system, an oxidation catalytic converter (46), downstream of the oxidation catalytic converter (46) an SCR catalytic converter (48) and downstream of the SCR catalytic converter (48) ) a particle filter (50) is arranged. Diesel hybrid drive according to one of the Claims 7 to 9 , characterized in that downstream of a particle filter (50) a low-pressure exhaust gas recirculation branches off from an exhaust gas duct (42) of the exhaust gas duct (42), which branches off the exhaust system (40) downstream of a turbine (44) of the exhaust gas turbocharger (26) with the intake duct (22 ) connects the air supply system (20) downstream of a throttle valve (24) and upstream of a compressor (28) of the exhaust gas turbocharger (26).

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