DE102018133046A1 - Motor vehicle, internal combustion engine for a motor vehicle and method for operating a motor vehicle - Google Patents

Abstract

The invention relates to a motor vehicle (1) which comprises an internal combustion engine (2), an exhaust gas aftertreatment system (3) coupled to the internal combustion engine (2) and a switchable transmission (4) which can be driven by means of the internal combustion engine (2). An actuating device (5) is provided, which is set up to prevent a flow of a medium (6) from at least one cylinder (7) of the internal combustion engine (2) into the exhaust gas aftertreatment system (3) as a function of a switching operation of the transmission (4) and thereby to prevent the exhaust gas aftertreatment system (3) from being exposed to the at least one medium (6). Further aspects of the invention relate to an internal combustion engine (2) for a motor vehicle (1) and a method for operating a motor vehicle (1).

Description

The invention relates to a motor vehicle which comprises an internal combustion engine, an exhaust gas aftertreatment system coupled to the internal combustion engine, and a switchable transmission which can be driven by means of the internal combustion engine. Further aspects of the invention relate to an internal combustion engine for a motor vehicle and a method for operating a motor vehicle.

When operating motor vehicles that are driven by internal combustion engines, it is common to use exhaust gas aftertreatment systems, which can include, for example, three-way catalytic converters, storage catalytic converters and particle filters, in order to avoid emitting impermissibly large amounts of pollutants into the environment. In order to achieve the best possible reduction of nitrogen oxides in three-way catalytic converters, so-called stoichiometric combustion with a combustion air ratio of “1” (λ = 1) is aimed for. For example, in order to enable low-pollutant shift operation of internal combustion engines, it is common to cause storage catalytic converters to be discharged in good time and to prevent the storage catalytic converters from being overcharged. In addition, it is known to carry out a so-called cylinder blanking in order to bring about a reduction in torque during a shifting operation of a transmission of a motor vehicle.

From the DE 42 39 711 A1 an internal combustion engine with several cylinders is known. During a shift operation, cylinder blanking is carried out to reduce the torque, so that each of the cylinders is not supplied with fuel and ignited within a predetermined time depending on the extent of the cylinder blanking. The other cylinder or cylinders are operated with fuel in the meantime, ie the cylinders are supplied with fuel and the air-fuel mixture is burned in the combustion chamber. The fired cylinders can change over all cylinders.

The DE 10 2013 008 734 A1 describes a method for cylinder blanking in an internal combustion engine in the switching process of a transmission, which works with deactivated cylinders without injection and ignition and at least one fired cylinder. The at least one fired cylinder alternates to another cylinder after its working cycle.

From the DE 198 52 600 A1 A method for operating an internal combustion engine of a motor vehicle is known, in which the fuel to be injected for combustion is injected directly into a combustion chamber of a cylinder in a first operating mode during a suction phase and in a second operating mode during a compression phase and then ignited in both operating modes, and in which nitrogen oxides generated during combustion are stored in a catalytic converter. An automatic transmission is assigned to the internal combustion engine. A gear change to a different gear stage or a different transmission range and a switchover to the first operating mode are carried out approximately simultaneously, the switchover to the first operating mode being provided for discharging the nitrogen oxides stored in the catalytic converter.

It is an object of the invention to provide a motor vehicle, an internal combustion engine and a method of the type mentioned at the outset by which reduced pollutant emissions can be achieved.

This object is achieved according to the invention by a motor vehicle with the features of claim 1, by an internal combustion engine with the features of claim 9 and by a method with the features of claim 10. Advantageous embodiments of the invention are the subject of the dependent claims and the description.

A first aspect of the invention relates to a motor vehicle which comprises an internal combustion engine, an exhaust gas aftertreatment system coupled to the internal combustion engine, and a switchable transmission which can be driven by means of the internal combustion engine. By means of the switchable transmission, drive power can be transmitted from the internal combustion engine to the respective drive wheels of the motor vehicle.

In order to achieve reduced pollutant emissions, an actuating device is provided according to the invention, which is set up to prevent a flow of a medium from at least one hidden cylinder of the internal combustion engine into the exhaust gas aftertreatment system as a function of a gearshift operation of the transmission and thereby to act upon the exhaust gas aftertreatment system with the at least one Prevent medium. The actuating device can be assigned to the internal combustion engine or the motor vehicle. It is advantageous to prevent the flow of the medium from the at least one hidden cylinder into the exhaust gas aftertreatment system as a function of the switching process, since this can prevent undesirable influences of the medium flowing out of the at least one hidden cylinder on the exhaust gas aftertreatment system. Under the terms "hide" or "hidden" is in the context of Understanding invention that cylinder blanking can take place in this cylinder. The medium can be, for example, air or a mixture of air and exhaust gas formed by exhaust gas recirculation, to name just a few examples. The internal combustion engine can preferably comprise a control device which is set up to control the actuating device as a function of the switching operation.

The invention is based on the knowledge that due to the cylinder blanking during the operation of conventional motor vehicles with conventional internal combustion engines, oxygen can enter downstream exhaust gas treatment systems in the respective internal combustion engines and can thus reach, for example, catalytic converters and, additionally or alternatively, particle filters. This can lead to an excess of oxygen in the exhaust gas aftertreatment systems or catalysts. When a fuel injection is subsequently reinstalled in previously hidden individual cylinders of the conventional internal combustion engines, the excess of oxygen in the catalytic converters can result in nitrogen oxide emissions, which can also be referred to as NOx emissions. If oxygen gets into the particle filter due to cylinder blanking, it may happen that soot required for ideal filtration in the particle filter is burned off.

The invention starts here because the actuating device can effectively prevent the exhaust gas aftertreatment system from being exposed to the medium.

In an advantageous development of the invention, the actuating device is set up to close at least one gas exchange valve from the gas exchange valves of the internal combustion engine associated with the at least one hidden cylinder, depending on the switching operation. This is advantageous since, by actuating the at least one gas exchange valve, the flow of the medium from the at least one hidden cylinder into the exhaust gas aftertreatment system can be reliably and reliably prevented.

In a further advantageous development of the invention, the actuating device comprises at least one shift rocker arm in order to close the at least one gas exchange valve as a function of the switching operation. This is advantageous because the at least one shift rocker arm can be used to easily vary a point in time and additionally or alternatively a stroke of the at least one gas exchange valve. The at least one rocker arm thus enables the at least one gas exchange valve of the hidden cylinder to be closed with little effort, that is, in other words, to keep it in a closed position in order to prevent the flow of the medium from the at least one hidden cylinder into the exhaust gas aftertreatment system.

In a further advantageous development of the invention, the actuating device comprises at least one sliding camshaft in order to close the at least one gas exchange valve as a function of the switching operation. This is advantageous since the at least one sliding camshaft can be used to easily vary a particular point in time and, in addition or alternatively, a respective stroke, even a plurality of gas exchange valves. The at least one sliding camshaft thus enables a plurality of gas exchange valves of the hidden cylinder to be closed with particularly little effort, that is to say to keep them in a respective closed position in other words in order to prevent the flow of the medium from the at least one hidden cylinder into the exhaust gas aftertreatment system.

In a further advantageous development of the invention, the actuating device is set up to close respective outlet valves of the gas exchange valves depending on the switching process. This is advantageous since the outlet valves can already be prevented from escaping from the at least one hidden cylinder in the direction of the exhaust gas aftertreatment system by closing the outlet valves. As a result, entry of the medium into an exhaust tract of the internal combustion engine or of the motor vehicle can be avoided and thus temperature-related loads on the exhaust tract resulting from the entry of the medium into the exhaust tract can be prevented. The actuating device can preferably be set up to close all outlet valves of the gas exchange valves depending on the switching process.

In a further advantageous development of the invention, the actuating device is set up to close the respective inlet valves of the gas exchange valves depending on the switching process. This is advantageous because, by closing the inlet valves, the medium in the cylinder and thus in a combustion chamber assigned to the cylinder can be prevented from being pushed out in the direction of an inlet tract of the internal combustion engine or the motor vehicle.

In a further advantageous development of the invention, the internal combustion engine has an injection system which is set up to prevent fuel from being injected into the at least one hidden cylinder as a function of the switching operation. This is from Advantage, since by preventing the injection of fuel into the at least one hidden cylinder, wetting of a cylinder wall with fuel and thus possible oil dilution can be avoided.

In a further advantageous development of the invention, the exhaust gas aftertreatment system comprises at least one catalytic converter and at least one particle filter. This is advantageous since the catalytic converter and the particle filter can be used to carry out a particularly extensive exhaust gas aftertreatment, and not only the escape of gaseous pollutants but also the escape of solids in the form of soot particles into the environment.

A second aspect of the invention relates to an internal combustion engine for a motor vehicle according to the first aspect of the invention. According to the invention, the internal combustion engine comprises a control device which is set up to control the actuating device as a function of the switching operation. The control unit can also be referred to as an engine control unit. The control device can in particular be designed to control the actuating device as a function of the shifting process, wherein the shifting process can bring about a reduction in tractive force during a gear shifting process, that is to say a gear change of the transmission.

The features presented in connection with the motor vehicle according to the invention according to the first aspect of the invention and their advantages apply accordingly to the internal combustion engine according to the invention according to the second aspect of the invention and vice versa.

A third aspect of the invention relates to a method for operating a motor vehicle, in which an internal combustion engine of the motor vehicle, an exhaust gas aftertreatment system of the motor vehicle coupled to the internal combustion engine, and a switchable transmission of the motor vehicle that can be driven by the internal combustion engine are operated at least temporarily during driving operation of the motor vehicle. According to the invention, a flow of a medium from at least one blanked-out cylinder of the internal combustion engine into the exhaust gas aftertreatment system is prevented by means of an actuating device as a function of a gearshift operation of the transmission, thereby preventing the exhaust gas aftertreatment system from being exposed to the at least one medium.

In an advantageous development of the invention, the flow of the medium into the exhaust gas aftertreatment system is prevented by means of the actuating device only during a reduction in the tensile force caused by the switching process. This is advantageous, since it enables the flow of the medium from the at least one hidden cylinder to be prevented from flowing into the exhaust gas aftertreatment system in a manner which is particularly tailored to requirements. If the transmission is designed, for example, as a double clutch transmission, the shifting process of the transmission is in principle possible without a reduction in tractive force, but a jump in gears, for example a shift between two even gears or two odd gears, can nevertheless result in a reduction in tractive force. In this case of skipping gears, the actuating device can be used to prevent the flow of the medium from the at least one hidden cylinder into the exhaust gas aftertreatment system.

The features presented in connection with the motor vehicle according to the first aspect of the invention and the internal combustion engine according to the second aspect of the invention and their advantages apply accordingly to the method according to the third aspect of the invention and vice versa.

Further features of the invention result from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the combination indicated in each case, but also in other combinations or on their own.

The invention will now be explained in more detail using a preferred exemplary embodiment and with reference to the drawing.

The sole FIG. 1 shows a schematic representation of a motor vehicle which comprises an internal combustion engine, an exhaust gas aftertreatment system coupled to the internal combustion engine, a switchable transmission which can be driven by the internal combustion engine, and an actuating device.

The only figure shows a schematic representation of a motor vehicle 1 which is an internal combustion engine 2nd , one with the internal combustion engine 2nd coupled exhaust gas aftertreatment system 3rd , and a switchable transmission 4th comprises which by means of the internal combustion engine 2nd is drivable. The gear 4th can be configured, for example, as an automatic transmission. The gear 4th serves from the internal combustion engine 2nd provided drive power on respective drive wheels of the motor vehicle, not shown here 1 transferred to. The exhaust aftertreatment system 3rd in the present case comprises a catalyst 14 and a particle filter 15 .

The internal combustion engine 2nd comprises a plurality of cylinders, only one cylinder in the present case for reasons of clarity 7 is shown and described in more detail. In the cylinder 7 is a piston 23 the internal combustion engine 2nd recorded and over a connecting rod 22 the internal combustion engine 2nd with a crankshaft 21st the internal combustion engine 2nd coupled.

The internal combustion engine 2nd is designed as a four-stroke engine, the piston 23 is movable between a top dead center and a bottom dead center. The cylinder 7 delimits a combustion chamber 26 in which by means of an injection valve 20 an injection system 17th the internal combustion engine 2nd Fuel injected and therefore with one in the combustion chamber 26 located medium 6 can be mixed. The medium 6 can be formed as air or as a mixture of exhaust gas recirculated by exhaust gas recirculation and air. The medium 6 can via an inlet duct 24th in the combustion chamber 26 be initiated.

The internal combustion engine 2nd includes one at least partially in the combustion chamber 26 protruding ignition source, which in the present case is a spark plug 19th is formed around the in the combustion chamber 26 brought in and with the medium 6 to ignite mixed fuel, thereby the piston 23 to move and using the piston 23 the crankshaft 21st to drive. The crankshaft is connected to an input shaft (not shown) of the transmission via a clutch (not shown here) 4th connectable. By burning the with the medium 6 mixed fuel, exhaust gas is formed, which via an exhaust port 25th out of the cylinder 7 and thus from the combustion chamber 26 can be diverted.

The internal combustion engine 2nd further includes respective, the cylinder 7 associated gas exchange valves 8th , 9 , 10 , 11 , of which the gas exchange valves 8th , 9 as exhaust valves and the gas exchange valves 10 , 11 are designed as inlet valves. In Fig. Cover the gas exchange valves 8th , 10 the gas exchange valves 9 , 11 . The gas exchange valve 9 is perpendicular to the plane of the drawing behind the gas exchange valves 8th and the gas exchange valve 11 perpendicular to the plane of the drawing behind the gas exchange valve 10 arranged.

The gas exchange valves 8th , 9 , 10 , 11 can in the present case by means of an actuating device 5 the internal combustion engine 2nd between a respective closed position of the gas exchange valves 8th , 9 , 10 , 11 and a respective open position of the gas exchange valves 8th , 9 , 10 , 11 be relocated to the combustion chamber 26 based on the gas exchange valves 8th , 9 temporarily opposite the outlet duct 25th to close and open or the combustion chamber 26 based on the gas exchange valves 10 , 11 temporarily opposite the inlet duct 24th to close and open.

The internal combustion engine 2nd includes a control unit 16 , which transmits signals with the actuator 5 is coupled. The control unit 16 is designed and set up a cylinder blanking in all cylinders of the internal combustion engine 2nd individually and therefore also with the cylinder 7 to control, the injection system 17th or the injection valve based on the control unit 16 can be temporarily deactivated. The actuator 5 is set up a flow of the medium 6 from the hidden cylinder 7 the internal combustion engine 2nd into the exhaust aftertreatment system 3rd depending on a gear shift 4th prevent and thereby an exposure to the exhaust gas aftertreatment system 3rd with the medium 6 to prevent, especially if the cylinder 7 is hidden, in other words subject to cylinder blanking.

The control unit 16 the internal combustion engine 2nd is set up the actuator 5 to be controlled as a function of the switching process in such a way that the actuating device 5 the flow of the medium 6 from the hidden cylinder 7 the internal combustion engine 2nd into the exhaust aftertreatment system 3rd during the gear shift 4th prevents and thereby the admission of the exhaust gas aftertreatment system 3rd with the medium 6 prevented. The control unit 16 is thus set up the actuator 5 to be controlled depending on the switching process.

In addition, the control unit 16 with at least one lambda probe 18th of the motor vehicle 1 coupled to transmit signals. The lambda sensor 18th can, as shown in the figure, in the outlet channel 25th be introduced to an oxygen content within the exhaust duct 25th to eat. Using the lambda sensor 18th can provide feedback to the control unit 16 done whether the actuator 5 the flow of the medium 6 from the hidden cylinder 7 (from the combustion chamber 26 of the hidden cylinder 7 ) effectively prevents.

The actuator 5 is set up to all, the hidden cylinder 7 associated gas exchange valves 8th , 9 , 10 , 11 in Lock depending on the switching process. With others is the actuator 5 set up to both the respective exhaust valves 8th , 9 as well as the respective intake valves 10 , 11 of the gas exchange valves 8th , 9 , 10 , 11 to close depending on the switching process. This can lead to the compression of the medium 6 in the cylinder 7 and thus in the combustion chamber 26 compression work (compression work) at least partially during a subsequent expansion and thus with a downward movement of the piston 23 towards bottom dead center for driving the crankshaft 21st be used even if there is no fuel injection into the combustion chamber 26 of the hidden cylinder 7 he follows.

The actuator 5 can comprise a plurality of shift rocker arms, of which only one shift rocker arm in the present case 12th is shown. The gear rocker arm 12th can also be called a switchable rocker arm. The shift rocker arms serve the gas exchange valves 8th , 9 , 10 , 11 to close depending on the switching process.

In addition or as an alternative to the shift rocker arms, the actuating device can 5 at least one sliding camshaft 13 include at least some of the gas exchange valves 8th , 9 , 10 , 11 to close depending on the switching process. The at least one sliding camshaft 13 and the shift rocker arm or the shift rocker arm 12th can a variable valve train 27 the internal combustion engine 2nd be assigned. In addition, the internal combustion engine 2nd at least one adjustment device 28 include the shift rocker arm and additionally or alternatively the at least one sliding camshaft 13 to operate. The actuating device can be used for the corresponding actuation 28 for example, comprise a plurality of actuators.

The injection system 17th the internal combustion engine 2nd is also set up to inject fuel into the hidden cylinder 7 to prevent depending on the switching process. The injection system 17th can do this using the control unit 16 are controlled by the injection of the fuel into the hidden cylinder 7 to prevent depending on the switching process.

During a driving operation of the motor vehicle 1 , the internal combustion engine 2nd , the exhaust aftertreatment system 3rd of the motor vehicle 1 , and the switchable, by means of the internal combustion engine 2nd drivable gears 4th of the motor vehicle 1 operated temporarily. Such “temporary operation” can, for example, in a start-stop operation of the motor vehicle 1 take place in which the internal combustion engine 2nd when the motor vehicle is at a standstill 1 is temporarily deactivated.

The present motor vehicle 1 or the actuator 5 In summary, enable an uncontrolled inflow of oxygen to be prevented in the exhaust gas aftertreatment system 3rd due to the flow of the medium 6 during cylinder blanking, by shifting the transmission 4th the gas exchange valves 8th , 9 (here: exhaust valves) and additionally or alternatively the gas exchange valves 10 , 11 (here: intake valves) are closed and kept closed. The control of the gas exchange valves 8th , 9 , 10 , 11 can be done by shift rocker arms and additionally or alternatively sliding camshafts during the switching process to the corresponding gas exchange valves 8th , 9 , 10 , 11 to keep closed during the switching process. This prevents oxygen from escaping to the catalyst in an uncontrolled manner 14 as well as the particle filter 15 reached. As a result, excessive nitrogen oxide emissions can be prevented and a filtration rate of the particulate filter 15 be maintained.

Reference list

1

Motor vehicle

2nd

Internal combustion engine

3rd

Exhaust aftertreatment system

4th

transmission

5

Actuator

6

medium

7

cylinder

8th

Gas exchange valve

9

Gas exchange valve

10th

Gas exchange valve

11

Gas exchange valve

12th

Shift rocker arm

13

Sliding camshaft

14

catalyst

15

Particle filter

16

Control unit

17th

Injection system

18th

Lambda sensor

19th

spark plug

20

Injector

21

crankshaft

22

Connecting rod

23

piston

24th

Inlet duct

25th

Exhaust duct

26

Combustion chamber

27

variable valve train

28

Actuator

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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 4239711 A1 [0003]
• DE 102013008734 A1 [0004]
• DE 19852600 A1 [0005]

Claims (11)

Motor vehicle (1) which comprises an internal combustion engine (2), an exhaust gas aftertreatment system (3) coupled to the internal combustion engine (2) and a switchable transmission (4) which can be driven by means of the internal combustion engine (2), characterized in that an actuating device ( 5) is provided, which is set up to prevent a flow of a medium (6) from at least one blanked cylinder (7) of the internal combustion engine (2) into the exhaust gas aftertreatment system (3) as a function of a switching operation of the transmission (4) and thereby to prevent the at least one medium (6) from being exposed to the exhaust gas aftertreatment system (3). Motor vehicle (1) after Claim 1 , characterized in that the actuating device (5) is set up to close at least one gas exchange valve from the gas exchange valves (8, 9, 10, 11) associated with the at least one hidden cylinder (7) of the internal combustion engine (2) as a function of the switching operation. Motor vehicle (1) after Claim 2 , characterized in that the actuating device (5) comprises at least one shift rocker arm (12) in order to close the at least one gas exchange valve as a function of the switching operation. Motor vehicle (1) after Claim 2 or 3rd , characterized in that the actuating device (5) comprises at least one sliding camshaft (13) in order to close the at least one gas exchange valve as a function of the switching operation. Motor vehicle (1) according to one of the Claims 2 to 4th , characterized in that the actuating device (5) is set up to close respective outlet valves (8, 9) of the gas exchange valves (8, 9, 10, 11) depending on the switching process. Motor vehicle (1) according to one of the Claims 2 to 5 , characterized in that the actuating device (5) is set up to close respective inlet valves (10, 11) of the gas exchange valves (8, 9, 10, 11) depending on the switching process. Motor vehicle (1) according to one of the preceding claims, characterized in that the internal combustion engine (2) has an injection system (17) which is set up to inject fuel into the at least one hidden cylinder (7) as a function of the switching operation prevent. Motor vehicle (1) according to one of the preceding claims, characterized in that the exhaust gas aftertreatment system (3) comprises at least one catalytic converter (14) and at least one particle filter (15). Internal combustion engine (2) for a motor vehicle (1) according to one of the Claims 1 to 8th , characterized in that the internal combustion engine (2) comprises a control device (16) which is set up to control the actuating device (5) as a function of the switching operation. Method for operating a motor vehicle (1), in which an internal combustion engine (2) of the motor vehicle (1), an exhaust gas aftertreatment system (3) of the motor vehicle (1) coupled to the internal combustion engine (2), and a switchable by means of the internal combustion engine (2) drivable transmission (4) of the motor vehicle (1) are operated at least temporarily during driving operation of the motor vehicle (1), characterized in that a flow of a medium (6) from at least one blanked cylinder (7) of the internal combustion engine (2) into the exhaust gas aftertreatment system (3) by means of an actuating device (5) in dependence on a switching operation of the transmission (4) is prevented, and thereby an exposure of the exhaust gas aftertreatment system (3) to the at least one medium (6) is prevented. Procedure according to Claim 10 , characterized in that the flow of the medium (6) into the exhaust gas aftertreatment system (3) on the basis of the actuating device (5) is only prevented during a reduction in tensile force caused by the switching process.

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