DE102018207208A1 - Motor vehicle with an exhaust gas aftertreatment device arranged in the exhaust system - Google Patents

Abstract

Motor vehicle comprising an internal combustion engine (2) with a downstream exhaust line (3), and at least one controllable heating element (6) associated with the exhaust line (3) and at least one exhaust after-treatment device (4) arranged in the exhaust line (3), wherein at least one of the internal combustion engine ( 2) associated electrically operable compressor element (8) via which the running or non-running internal combustion engine (2), a gas can be supplied via a bypass line (10) with the exhaust line (3) for supplying a via the heating element (6) heatable gas not running or in overrun internal combustion engine (2) is connected.

Description

The invention relates to a motor vehicle, comprising an internal combustion engine with a downstream exhaust gas line, and at least one controllable heating element associated with the exhaust gas line and at least one exhaust gas after-treatment device arranged in the exhaust gas line.

Modern motor vehicles usually have at least one exhaust gas aftertreatment device arranged in the exhaust line in the form of a catalyst which is used to purify the exhaust gas which is produced during the combustion of the fuel in the internal combustion engine, that is to say it reduces any pollutants contained in the exhaust gas serves. An optimum cleaning performance of the catalyst at a sufficient temperature, which is several 100 ° C, wherein the catalyst is heated by the hot gas. However, so that the catalyst is already functional immediately after the start and reaches its starting temperature of about 250 ° C, it is known to assign him an electrically operable heating element, such as an electric heater. An example of this is off DE 42 25 274 A1 known, in the motor vehicle described there, the heater is already switched on when the pending or occurred boarding of a person was detected in the motor vehicle, for example via a door opening system. This active heating ensures that the catalyst already at start has the starting temperature and can therefore provide its cleaning effect.

At the DE 42 25 274 A1 known motor vehicle, the heating element is located directly on the catalyst and this, as seen in the exhaust gas flow direction, upstream of the front end. Although a conditioning of the catalyst itself can be achieved by this, but not a conditioning and thus preheating other exhaust aftertreatment in the exhaust system, which are also to bring to temperature. An example of this are further downstream catalysts. In addition, however, other components present in the exhaust gas line, such as valves or flaps, are to be brought to temperature during operation in order to ensure their function and, for example, to avoid sooting. However, such a temperature conditioning is not possible by only local heating of the one catalytic converter when the internal combustion engine is not working, that is to say that these additional exhaust gas after-treatment components or components can only be brought to temperature when the internal combustion engine is running and consequently a sufficient exhaust gas mass flow is available.

The invention is thus based on the problem of specifying a motor vehicle which is improved by comparison.

To solve this problem, it is provided according to the invention in a motor vehicle of the type mentioned above that a gas can be fed to the internal or non-running internal combustion engine, via a bypass line with the exhaust line for supplying a heatable via the heating element Gas in running, not running or operating in overrun internal combustion engine is connected.

The invention provides for actively supplying a gas to the exhaust gas line when the internal combustion engine is not operating for temperature conditioning of the exhaust gas line and the exhaust gas cleaning components or other components to be tempered, which is heated via the heating element operated at the same time. Hereby, a gas mass flow is ensured by the exhaust system, which, after the heating element of the at least one exhaust aftertreatment device, ie, for. B. is upstream of the catalyst, that is therefore arranged in a front region of the exhaust system, heated by the heating element and flows as hot gas through the exhaust line, in which case the corresponding cleaning components and functional components are heated, without the internal combustion engine is working. This actively heated gas mass flow thus enables a targeted increase in temperature within the exhaust line or to the corresponding exhaust treatment components such as catalysts and valves, flaps, etc., so that these already at a subsequent start of the internal combustion engine, so if actual to be cleaned exhaust gas is generated, their starting temperature or Have reached operating temperature and therefore can either make the cleaning process, or as far as their function, temperature optimized. Overall, an efficiency-optimal temperature level in the exhaust gas line can already be achieved at the engine start, on the one hand with regard to the cleaning efficiency, on the other hand with regard to the avoidance of sooting problems by the exhaust gas and the like.

The active gas supply via the at least one electrically operable compressor element in the exhaust system can be done not only when not running internal combustion engine for temperature conditioning, but also when operating in overrun internal combustion engine. In this case, with the heating element switched on at the same time, maintaining the temperature level in the exhaust gas line can be achieved by means of this active gas mass flow after exhaustive operation, no exhaust gas enters the exhaust system, which could keep the temperature level.

The temperature conditioning can be done not only for internal combustion engine but not only for targeted heating, but also for a temperature drop, namely, when the motor vehicle is turned off and the exhaust gas system components are very hot. By selectively supplying tempered air, the temperature level can be lowered rapidly, without the risk that by supplying non-preheated gas, the temperature gradient within the exhaust line is too large and there is damage to the still hot exhaust gas components.

A central element is, as described, the at least one of the internal combustion engine associated electrically operable compressor element, which is usually integrated in the intake air path of the internal combustion engine and serves to actively promote air in the intake air path. For example, a flow or displacement compressor is provided for this purpose. This compressor element is now in the operating situations described above, where it is not required to supply the engine gas or air used to promote the gas or the air in the exhaust system, to which the compressor element is connected via a corresponding bypass line to the exhaust system. This means that an already existing component, namely the at least one compressor element, is used in these operating situations in a second function, namely to push an active gas mass flow through the exhaust gas line.

To ensure that the gas supplied by the compressor element or the air is supplied to the exhaust line and not the intake tract and thus the internal combustion engine in the corresponding operating situations, it is expedient to close the intake and exhaust valves of the engine, so that the flow path through the Engine is virtually closed and the air or gas via the bypass leads to the exhaust system. Conveniently, this can also be alternatively or additionally provided a switchable valve arrangement, via which the compressor element is connected to the internal combustion engine and the bypass line, which thus, without the engine-side intake and exhaust valves are actuated, performs the corresponding flow path control. This can be ensured that in each case the required gas or air mass flow rate is achieved through the exhaust system.

The heating element itself may for example be an electric heating element, which is arranged for example on the catalyst itself, and serves to heat it. Since it is achieved via the gas or air mass flow that this gas flows through the entire exhaust gas line for conditioning, a heating element arranged on the first catalytic converter in the flow direction is already sufficient. But it does not have to be directly on the catalyst, but can also be provided at another, upstream position on or in the exhaust system.

An electrical heating element can be, for example, a heating device with an incandescent filament or a directly energized catalyst component.

Alternatively, a heating element having a fuel burning burner device or embodied as such may also be used. This burner device, which is preferably connected via a line to a fuel tank of the motor vehicle, burns this fuel, be it liquid, be it gaseous, in order to heat the gas supplied via the bypass line.

The operation of the compressor element and the heating element is expediently controlled via a common control device as a function of at least one of a future commissioning of the internal combustion engine or a coasting operation of the internal combustion engine information indicating, but this also separate control devices can be used. That is, corresponding information is acquired on the vehicle side, indicating a respective future operating mode requiring active temperature conditioning of the exhaust line, depending on which then the corresponding control of the compressor element and the Heizelementbetriebs takes place. As such information, for example, the unlocking of a vehicle door by the driver itself, serve, or the actual active opening of the vehicle door by the driver. Alternatively, the unlocking signal of a radio key, via which the doors or flaps of the vehicle are unlocked serve. Alternatively, this may also be predictive vehicle functions or information announcing overrun or engine stall. If such information is detected, this serves as a trigger signal to control the corresponding, the preheating serving components.

In addition to the motor vehicle itself, the invention further relates to a method for operating a motor vehicle comprising an internal combustion engine with a downstream exhaust line and at least one controllable heating element associated with the exhaust line and at least one arranged in the exhaust line Exhaust treatment device. The method is characterized in that by means of one of the internal combustion engine associated electrically operable compressor element via the current internal combustion engine, a gas, in particular air in non-running or in overrun internal combustion engine to the exhaust system via a bypass line, a gas, in particular air is supplied by of the exhaust gas aftertreatment device upstream heating element is heated.

In this case, the compressor element can be connected via a switchable valve arrangement with the internal combustion engine or the bypass line, wherein the valve arrangement is opened for supplying the gas to the bypass line and closed again after completion of the gas supply. If, for example, the inlet and outlet valves of the engine are closed in the corresponding situations in which the additional active heating is required, then it is sufficient to provide a corresponding valve only for opening and closing the bypass. However, if the engine-side valves are not closed, it is also possible to provide a valve which opens and closes the intake tract and which, when the gas or air is to be supplied to the exhaust gas line via the bypass, is correspondingly closed.

As heating element, an electrical heating element, in particular a heating element arranged on a catalytic converter, or a burner device burning a fuel can be used, wherein the burner device is expediently connected via a line to a fuel tank of the vehicle.

The operation of the compressor element and the heating element itself is suitably controlled via a common or separate control device as a function of at least one future commissioning of the internal combustion engine or an overrun of the internal combustion engine information indicating, for example, unlocking a vehicle door, the opening of a vehicle door or unlocking a Radio key is used.

Further advantages and details of the present invention will become apparent from the embodiment described below and from the drawing.

The single FIGURE shows a partial view of a motor vehicle according to the invention 1 comprising an internal combustion engine 2 with a downstream exhaust line 3 in which in the example shown several exhaust aftertreatment devices 4 , for example in the form of various cascaded catalysts 5 are provided. The first catalyst in the exhaust gas flow direction 5 upstream is an electrically operable heater 6 , For example, a filament or a directly energized catalyst component or the like.

The internal combustion engine 2 is in the air intake line 7 a compressor element 8th , For example, upstream of a flow or displacement compressor, via the over the air intake 7 the internal combustion engine 2 Air can be supplied to these for combustion operation in a fuel tank 9 needed fuel needed. The air intake 7 respectively the compressor element 8th is over a bypass route 10 with the exhaust system 3 connected. This makes it possible, if necessary, via the compressor element 8th either the internal combustion engine 2 to supply the gas required for combustion there respectively air, or optionally via the bypass line 10 the gas or the air in the exhaust system 3 to promote. To make this possible, it is conceivable, a valve assembly 11 , which can be switched accordingly, provide over which either the air intake tract 7 to the internal combustion engine 2 opened and the bypass line 10 is closed, or about the air intake 7 closed and the bypass line 10 is opened. Such a valve arrangement 11 However, it is optional, if it is already sufficient, the corresponding flow paths alone on the closed position or open position of the intake and exhaust valves of the internal combustion engine 2 to control.

Furthermore, a common control device is provided in the example shown 12 in the present case, the operation of the electrically operable compressor element 8th , the optional valve assembly 11 , as well as the heating element 6 controls. This control device 12 receives for example via a vehicle-side bus 13 Information regarding a forthcoming or just commencing corresponding operating mode of the motor vehicle. For example, this information is detected, indicating that is expected shortly with a start of the internal combustion engine. Such information may be, for example, the receipt of an unlocking signal of a radio transmission key or an active opening of the driver's door. Alternatively, this information can also be a transition into a pushing operation on the part of the internal combustion engine 2 indicating information.

Based on this information, the controller controls 12 now the electrically operable compressor element 8th , optionally the valve assembly 11 and in any case also the heating element 6 on, allowing air from the compressor element 8th over the bypass line 10 in the exhaust system 3 is encouraged.

If, for example, a pending engine start is detected, then before starting the engine actively an air mass flow through the exhaust system 3 resulting from the conveyance of air through the compressor element 8th through the bypass line 10 be obtained, wherein the supplied air is heated via the simultaneously switched heating element, so that the corresponding exhaust gas purification facilities 4 So here are the catalysts 5 , resulting from the heated, hot air mass flow rate can be heated to their starting temperature or beyond even before the actual engine start, so that when resulting from the engine start actively to be cleaned exhaust gas is generated, the corresponding cleaning components are already fully operational and immediately cleaning can be done. However, other cleaning or functional devices that are integrated in the exhaust line, such as valves or flaps or the like, are preheated by the hot air mass flow, for example, to a sooting or other damage to these components, resulting from too low a temperature at engine start avoid.

Once the internal combustion engine 2 is started, respectively immediately before or at the beginning of the start of the internal combustion engine 2 , this preheating or preconditioning can be switched off again, that is, the compressor element 8th the sucked air again only the air intake 7 and thus the internal combustion engine 2 feeds, but not more of the bypass line 10 , Then the normal engine operation takes place. Only when, for example, via the control device 12 again a boost operation is sensed, the switch can be made again to the active air mass flow rate through the exhaust line 3 in connection with the heating via the heating element 6 keep the temperature in the exhaust system at an appropriate level. The of the control device 12 detected information is in this case an information indicating the overrun operation, whereupon the corresponding components are controlled.

The above is stated that it is the heating element 6 around an electrically operable heating element 6 which can be switched accordingly. Alternatively, this may also be a burner device that is in the tank 9 located fuel, be it a liquid, be it a gas, to heat the exhaust tract 3 can burn. This is the heating element 6 over the here shown only dashed line 14 with the fuel tank 9 connected to, possibly in conjunction with a corresponding feed pump, to draw from this the fuel. However, the basic function is the same as for an electric heating element, it is then switched on when the corresponding operating mode of the motor vehicle requires to perform a temperature conditioning in the exhaust system, and it is turned off when this conditioning is done or is no longer necessary ,

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 4225274 A1 [0002, 0003]

Claims (14)

Motor vehicle, comprising an internal combustion engine (2) with a downstream exhaust line (3), and at least one controllable heating element (6) associated with the exhaust line (3) and at least one exhaust aftertreatment device (4) arranged in the exhaust line (3), characterized in that at least one the internal combustion engine (2) associated electrically operable compressor element (8) via which the running or non-running internal combustion engine (2), a gas can be supplied via a bypass line (10) with the exhaust line (3) for supplying a via the heating element (6) heatable gas in non-running or in overrun operating internal combustion engine (2) is connected. Motor vehicle after Claim 1 , characterized in that the compressor element (8) is a flow or displacement compressor. Motor vehicle after Claim 1 or 2 , characterized in that the compressor element (8) via a switchable valve assembly (11) with the internal combustion engine (2) and the bypass line (10) is connected. Motor vehicle according to one of the preceding claims, characterized in that the heating element (6) is an electrical heating element. Motor vehicle after Claim 4 , characterized in that the electric heating element (6) is arranged on the exhaust gas aftertreatment device (4) and serves to heat it. Motor vehicle according to one of Claims 1 to 3 , characterized in that the heating element (6) is a fuel burner burning a fuel. Motor vehicle after Claim 6 , characterized in that the burner device via a line (14) with a fuel tank (9) of the motor vehicle (1) is connected. Motor vehicle according to one of the preceding claims, characterized in that the operation of the compressor element (8) and the heating element (6) via a common or separate control device (12) depending on at least one of a future commissioning of the internal combustion engine (2) or a pushing operation or a Standstill of the internal combustion engine (2) indicating information is controllable. Motor vehicle after Claim 8 , characterized in that serve as information unlocking a vehicle door, the unlocking signal of a radio key or the opening of a vehicle door or predictive vehicle information announcing a coasting or engine stall. Method for operating a motor vehicle (1) comprising an internal combustion engine (2) with a downstream exhaust line (3), and at least one controllable heating element (6) associated with the exhaust line (3) and at least one exhaust gas after-treatment device (4) arranged in the exhaust line (3), characterized in that by means of one of the internal combustion engine (2) associated electrically operable compressor element (8) through which the current internal combustion engine (2), a gas is supplied to the exhaust line (3) via a non-operating or in overrun internal combustion engine (2) Bypass line (10), a gas is supplied, which is heated by means of the exhaust aftertreatment device (4) upstream heating element (6). Method according to Claim 10 , characterized in that the compressor element (8) via a switchable valve assembly (11) with the internal combustion engine (2) and the bypass line (10) is connected, wherein for supplying the gas to the bypass line (10) the valve assembly (11) is opened and after Termination of the gas supply is closed again. Method according to Claim 10 or 11 characterized in that an electrical heating element, in particular a heating element arranged on the exhaust-gas aftertreatment device (4) or a burner device burning a fuel, is used as the heating element (6). Method according to one of Claims 10 to 12 , characterized in that the operation of the compressor element (8) and the heating element (6) via a common or separate control device (12) depending on at least one of a future commissioning of the internal combustion engine (2) or a coasting operation or a stoppage of the internal combustion engine (2) indicating information is controlled. Method according to Claim 13 , characterized in that serve as information unlocking a vehicle door, the unlocking signal of a radio transmission key or the opening of a vehicle door or predictive vehicle information announcing overrun or engine stall.

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