DE102007028915A1 - Method for driving motor vehicle, involves feeding energy recovered by energy converter to heating apparatus and operating heating apparatus for heating exhaust gas with recovered energy - Google Patents

Abstract

The method involves detecting a potential for energy recovery. An energy converter (11) is activated. The energy, which is recovered by the energy converter, is fed to the heating apparatus (4). The heating apparatus (4) is operated for heating the exhaust gas (6) with the recovered energy. An end of the potential is detected for energy recovery, after which the energy converter is deactivated and the provision of the recovered energy is ended.

Description

The The present invention relates to a method for operating a motor vehicle. as components a drive means, an exhaust system for exhaust gases the drive means with at least one heater and at least having an energy converter. The invention finds particular application in the automotive industry.

It is to be regarded as known, that of an engine of a motor vehicle produced exhaust gas with a heater in contact, to influence the temperature of the exhaust gas. Furthermore is also to be regarded as known that such heaters, for example just after a cold or restart of an engine or an exhaust system be used to the exhaust gases or the exhaust gas purification components, optionally provided with a catalytically active coating are to bring quickly to the reaction temperature, in particular to a temperature at which an interaction of the catalyst with the pollutants of the exhaust gas takes place.

When Heating devices are in particular already proposed which is heated as a result of ohmic resistance heating become. The one to desired Times with current flowing through electrical conductors heats up due to its resistance and thus can be positioned on it catalytically active material and / or heat the contacted exhaust gas. The Embodiments of such heaters are manifold, in particular are wire mesh structures, Honeycombs, Plate constructions and similar Apparatuses have already been described.

in the Regarding the operation of such heaters is also be regarded as known that these before or with engine start or possibly shortly after engine start to improve the cold start behavior for one limited period have been activated, taking particular account that was an electrical overload the battery of the vehicle is avoided. In addition, it is also known use such heaters in combination with particulate filters, in case of need (eg a threatening blockage of the particle filter) to allow a thermal regeneration of the trapped particles. For this purpose, it is known to activate the heater, if a given operating period has elapsed and / or the particle load in the filter reaches a predetermined size Has.

The However, known purposes and / or deployment strategies led only partially to the desired Results. In particular, it had to be stated that the use the heater partially an undesirably high energy demand for Sequence and the activation cycles sometimes took very long periods.

Of these, It is an object of the present invention, with reference At least partially attributed to the prior art problems to solve. In particular, a method is to be specified which saves energy and effectively using such heaters in exhaust systems more mobile Internal combustion engines allows.

These Tasks are solved with a method according to the features of claim 1. Further advantageous embodiments and applications The invention will become dependent on formulated claims specified. It should be noted that the individual in the claims listed Features in any, technologically meaningful way with each other can be combined and show further embodiments of the invention. The invention becomes hereafter just in connection with the description and further specified in the figures, so that here too particularly preferred variants are indicated.

• (a) Erfassen einer Möglichkeit zur Energierückgewinnung,
• (b) Aktivieren des wenigstens einen Energiewandlers,
• (c) Zuführen der von dem wenigstens einen Energiewandler rückgewonnenen Energie zu der Heizvorrichtung,
• (d) Betreiben der Heizvorrichtung zur Aufheizung des Abgases mit der rückgewonnenen Energie, und
• (e) Erfassen eines Endes des Möglichkeit zur Energierückgewinnung, wonach der Energiewandler deaktiviert und die Bereitstellung der rückgewonnenen Energie beendet wird

The inventive method for operating a motor vehicle having as components a drive means, an exhaust system for exhaust gases of the drive means with at least one heating device and at least one energy converter comprising at least the following steps:

• (a) detecting a possibility for energy recovery,
• (b) activating the at least one energy converter,
• (c) supplying the energy recovered by the at least one energy converter to the heating device,
• (d) operating the heater to heat the exhaust gas with the recovered energy, and
• (e) detecting an end of the opportunity for energy recovery, after which the energy converter is deactivated and the provision of the recovered energy is stopped

In order to relates to the method according to the invention in particular the regulation of a with the exhaust gas of a motor vehicle engine in contact heating device, so that a desired Target parameters of the exhaust system or a component in safe is reached.

In addition to known diesel or gasoline engines, the drive means can also be any other comparable drive which ultimately produces an exhaust gas loaded with pollutant or an exhaust gas which undergoes a temperature treatment should be subjected to. These include hybrid powertrains or propellants based on alternative energy sources that emit exhaust gases. The "exhaust system" is regularly formed with a strand (or more strands), in particular in the manner of a tubular conduit. In this, the exhaust gas in a preferred flow direction leading exhaust system now at least one heating device is provided which spans, in particular at least partially over the inner cross section of the exhaust system. In this case, the heating device preferably forms passages, channels or the like, through which the exhaust gas flows, wherein a large contact surface is realized. The heater may have additional functions in addition to its heating function, such as catalytic conversion, storage, or diversion of exhaust components.

According to step (a) will be first a possibility for energy recovery detected. This happens, for example, in which at least one driving and / or Operating state of the motor vehicle (preferably continuously) by means of monitored a control device becomes. At predetermined states, at which it is possible is to regain energy, will then generates a corresponding signal indicating that the possibility for energy recovery consists. Within the scope of the invention, this may optionally include current, d. H. current, states to determine the possibility for energy recovery be used. But it is also possible future, expected, conditions at the capture of opportunities for energy recovery consulted. This can be done, for example, by means of a GPS navigation device happen. If it is recognized, for example, that a vehicle on a longer one Downgrade is located and the direction of travel also points in the direction of the descent, so is to expect that the vehicle in the near future predominantly in the braking or idling state and thus an energy recovery possible will be. In addition to such a very particularly advantageous driving condition, which an excellent opportunity for energy recovery represents, can but also in numerous other states or situations energy recoveries be made. These are for example braking operations high speeds or shorter slopes.

in the Subsequent step (b) of the method then becomes at least one Energy converter activated. Becomes a signal as a result of step (a) issued the possibility indicating energy recovery, so step (b) activates the energy converter as a result of the signal. The energy converter then preferably gains kinetic energy, which is stored or generated in the vehicle, returns and converts this into another form of energy (preferably electricity) - recuperation. Besides the conversion of kinetic energy, it is also here conceivable to convert potential energy of the motor vehicle. This could for example, by changes in altitude as part of the suspension kinematics, where spring paths for energy recovery can be used.

When Energy converters come into consideration, for example, power generators. these can the rotational movements of the wheels (in particular the braking energy) or the drive elements of the vehicle convert to electricity. Alternatively, in hybrid vehicles but also their electric motors, which in a drive state to drive serve the vehicle, in overrun operation as generators for production be used by electricity. Other forms of energy converters can Be compressors, the rotational movements, for example, the drive elements into pressure potentials of compressed air storage, later indirectly or be used immediately.

In Step (c) then becomes that of the at least one energy converter recovered Energy supplied to the heater. This happens in the simplest way Case over Conduction means, such as in the form of electrical lines, when the recovered Energy in the form of electrical currents is present. Nevertheless, step (c) can also be multi-stage, where z. B. first an energy store with the recovered Energy is supplied and at a later time as needed the Heating device is supplied. Charging the energy storage can also simultaneously or parallel to the supply of the recovered energy towards the Heater done.

The method according to the invention further provides, in step (d), to operate the heating device for heating the exhaust gas with the recovered energy. The heater can act directly or indirectly on the heated exhaust gas. In a direct-acting heater, for example, heating coils are provided, which are arranged directly in the exhaust gas flow and are flowed around there by the exhaust gas. If they are made to glow by electric current, for example, then the energy provided is discharged from the heating device to the exhaust gas flowing around it, and the latter is thereby heated. The thus heated exhaust gas can then reach the required temperatures for complete exhaust gas purification faster. When operating an immediate heating device, this can act, for example, on the honeycomb body or other components of the exhaust system. This means the exhaust system or its components are heated by the heater and in turn then heat the exhaust gas flowing through the exhaust system again. Here by results in the immediate mode of action of the heater.

ever according to the form of use and vehicle, the recovered energy can be different Replace or supplement energy sources in whole or in part. While, for example previously common Heating devices are operated with electric currents, which provided by generators and vehicle batteries lead this often too high loads on the electrical systems. In addition, results from the use of 12 or 24 Voltsystemen also a considerable restriction in view of the maximum possible Power output of such systems. Starting from this state of the Technique can now optionally by means of the present invention the from the usual Energy sources derived heating energy through the recovered energy all or partially replaced. this leads to to a particularly strong relief of electrical systems.

is in other cases of objection a particularly high heating power desired, for example, if required preferably complete Exhaust aftertreatment, so the recovered energy can also in addition to the previous heating energy sources used to heat the exhaust gas which are significantly higher Heating capacities as previously possible become. About that In addition, it is now ensured that in driving situations, which in principle to Cooling lead the exhaust system, because no sufficient amount of hot exhaust gas is generated, directly a heating of the "cooler" exhaust gases takes place and thus the activity or effectiveness the exhaust gas purification components of the exhaust system maintained is (especially in diesel engines).

in the Step (e) of the invention eventually becomes the end of the possibility recorded for energy recovery, after which the energy converter deactivates and the provision of the recovered Energy is stopped. This ensures that a vehicle not braked in any condition or energy in any other way is taken when this energy is primarily needed for other purposes. For example, an acceleration process may be mentioned here the available standing power or amount of energy as completely as possible Acceleration of the vehicle to be used. In such a Driving condition would be it not desirable and sometimes even safety-relevant, if available Drive power partly in the context of energy recovery would be converted. In step (e), the energy recovery is thus terminated and the vehicle as it were placed in a waiting state in which it remains until a new opportunity for Energy recovery established.

All it is particularly preferred according to the present invention Invention, when the method described above at least at a partial load of the drive means or below a minimum exhaust gas temperature accomplished becomes. A possible Border for a partial load range is 80%. That means only if the drive means of the motor vehicle with a load of 80% or less, an energy recovery can be performed should. Other load limits can for example, be defined at 60% or 30%, thereby ensuring will that no energy recovery is made when the engine or the drive means with a Power is operated, which are above these partial load limits. in principle can the load limits also to an average and / or current Be bound exhaust gas temperature, so that even at lower temperatures despite high partial load ranges (eg 80%) is already heated. Conversely, at high exhaust gas temperatures, a heating can be omitted, even if the partial load is very small and for example under 30% lies. This temperature used to control the heating then sets a predetermined minimum exhaust gas temperature (eg 400 ° C, or 300 ° C or too 200 ° C), at the still a sufficient effectiveness and exhaust aftertreatment by the exhaust gas cleaning device is ensured.

All it is also particularly advantageous if the steps (a) to (e) from a controller connected to the components be executed. Under a control device in this case is a device understood, which is capable of different parameter signals and / or measured values of a vehicle to capture, this accordingly given conditions, situations, conditions and / or laws analyzed and outputs appropriate control commands. Such Control device can physically on a device or else distributed in the vehicle to be executed on a variety of so-called control devices. In particular, it should also be noted that control programs be processed on such control devices, in which the Procedural steps are stored in program-technical form.

Control devices can be found in almost all modern vehicles and can also be prepared and used by appropriate adaptation of control programs in a simple form for carrying out the method according to the present invention. Such controllers are particularly powerful and can monitor and account for a variety of parameters in near real-time. In particular, be on a connection and control devices with Naviga tion facilities pointed out, which is possible in the context of the present invention in an advantageous manner.

According to one Another advantageous embodiment of the present invention provided, by the control device continuously at least an energy absorption capacity or an energy delivery capability monitor at least one energy store or a consumer. It can be provided that the energy delivery capability and / or the energy absorption capacity of the Energy storage and / or consumers monitored with a control device becomes. Such consumers are, for example, those mentioned above Heating device or other energy consumers such as Control devices, Electric drives of hybrid vehicles or electric vehicles or else that of energy storage, such as accumulators or Capacitors.

in this connection Above all, particularly powerful capacitors are known, in vehicles for temporary storage of large amounts of energy serve. Quite preferred is the use of double-layer capacitors, Also electrochemical double-layer capacitors (English: electrochemical double layer capacitor - EDLC) or supercapacitors. Double-layer capacitors consist of two electrodes, which are wetted with an electrolyte. When applying a voltage, which is less than the decomposition voltage of the electrolyte, collect At both electrodes ions of opposite polarization. They form one Zone of immovable load carriers, whose layer thickness is only a few molecule layers. Such double-layer capacitors have across from Accumulators very high specific power density (watts / kg), which is determined by the internal resistance. Such high power densities favor Applications for the buffering of consumers who temporarily use a need high power or deliver (In here mentioned Automotive sector may have a corresponding Electromotive brake in electric, hybrid and gyro powered vehicles because they have sufficiently large drive motors and energy storage.). These capacitors can in contrast to previously known accumulators electrical energy very fast and in big Cache quantity. They are thus in particular for short-term and rapid caching of the recovered energy.

insofar it is advantageous to the energy storage capacity and energy delivery capability to monitor such energy storage, around the recovered Energy provided by the energy converter there temporarily temporarily. It should be noted that in the case of caching the recovered one Energy in a buffer of step (s) of the method according to the invention a time delay between the deactivation of the energy converter and the termination the provision of the recovered Can provide energy. In the remaining time after deactivation The energy converter can provide the recovered Energy namely by means of the previously filled Energy storage done, which is the cached energy still for Give a certain amount of time to the heater. hereby can also after an end of recovery a Nachhei tion with the cached energy done. This is particularly useful during idle periods, for example directly or with a time delay at phases of energy recovery connect. An idle phase can be, for example, a waiting time before a Form the traffic light system. In addition, it may make sense in certain cases be, the recovered To divide energy and to a plurality of consumers or stores forward. This is especially true for vehicles with electric drives in energy recovery a very high power output occur. That means very much a short time will be a big one Generated amount of energy that needs to be consumed or stored. Such amounts of energy can be monitored and distributed for example by a control device. in this connection For example, does it make sense to have some of the energy in one? Consuming heater and another part in a storage device to store, with both steps depending on the one to be recorded Amount of energy can be executed in parallel or in succession.

As mentioned earlier, it is advantageously provided in the context of the present invention, the method of step (b) by means of at least one electric motor or generator. Such electric motors and / or generators are found in modern vehicles, for example with hybrid drive or with pure electric drive, already application and can for generating electrical currents and thus as an energy converter be used. But even so far only by internal combustion engines driven vehicles can Such electric motors or generators in addition as drive or as Energy converters are arranged in the vehicle.

In addition, in the context of the present method for carrying out step (d), preferably at least one electrically heatable honeycomb body is used as the heating device. Such an electrically heatable honeycomb body may be formed either ceramic or metallic or a combination of both types of materials. Such heatable honeycomb bodies are also already in the art in a variety of Ausgestal tions and have also proven themselves. In this case, preference is given to honeycomb bodies which are constructed with at least partially structured sheet metal layers which form electrically insulated, wound winding current paths which extend over the cross section of the honeycomb body.

Especially it is also advantageous if during the step (d) an exhaust gas mass flow is at least partially recycled. This allows the relatively cold exhaust gas mass flow to be heated up considerably be reduced in its mass by this at least partially back again is slid into the internal combustion engine. By reducing the to be heated exhaust gas mass flow, the remaining non-recirculated exhaust gas mass flow then to a higher one Temperature can be heated or it may be required for heating Heating power without lowering the temperature can be reduced accordingly. Alternatively, both can be the case. In particular, a reduction The heating power relieves the electrical system of the vehicle and allows an extended one Heating time with the recovered Energy.

Especially Advantageously, the invention is used in a motor vehicle, comprising at least one drive means and an exhaust system with at least one controllable and can be brought into contact with exhaust gas Heating device, in which at least the with a control device connected heating device for carrying out the present invention described here Procedure is set up.

The Invention and the technical environment are based on the figures explained in more detail. It It should be noted that the figures are particularly preferred embodiments of the invention, but not limited thereto. They show schematically:

1 a side view of a motor vehicle for carrying out the method according to the invention;

2 : a top view of the vehicle behind 1 ;

3 a plan view of a second embodiment of a motor vehicle; and

4 : A plan view of a third embodiment of a motor vehicle.

In 1 is a motor vehicle 1 shown for carrying out the method according to the invention. The car 1 consists of various components, which include a drive means 2 , an exhaust system 3 and a heater 4 belong. The drive means 2 is as an internal combustion engine 5 formed, which is an exhaust 6 produced and through the exhaust system 3 towards a catalyst 7 promotes from where it is treated by a rear part of the exhaust system 3 to a vehicle rear 8th is directed where it exits to the outside. The catalyst 7 includes next to the heater 4 another (at least one other) honeycomb body 9 which may be formed metallic or ceramic and provided with various catalytically active, adsorbent or other coatings. In the honeycomb body 9 becomes the incomplete "cleaned" exhaust gas 6 treated at appropriate temperatures. To achieve the favorable or required for the conversion temperatures, the heater 4 upstream of the honeycomb body 9 arranged.

At the wheels 10 are each energy converters 11 arranged via conduit means 12 with the heater 4 are connected. Furthermore, the energy converters 11 via control lines 13 with a control device 14 connected.

In 2 is the motor vehicle 1 out 1 shown in a plan view. There again is the control device 14 identifiable via control lines 13 with each of the four energy converters 11 and additionally with the combustion engine 5 connected is. The control lines 13 They are used optionally to send control commands or to query measured values and parameters. The term control line is thus also to be understood in the sense of a signal transmission line. In 2 It is also clear that on each of the wheels 10 an energy converter 11 is arranged. The in each of the energy converters 11 recovered electrical energy is transmitted via the conduit 12 directly into the heater 4 initiated. In the embodiment shown, the execution of the method according to the invention by the control device 14 first detects the possibility of energy recovery and then via the control lines 13 Signals to the energy converters 11 to activate them. After activation of the energy converter 11 , is recovered by this, the kinetic energy of the rotating wheels and the conduit means 12 in the form of an electric current to the heater 4 forwarded where they initiated according to the arrows shown and for heating the exhaust gas 6 is converted into heat. The energy converter 11 are formed in the illustrated embodiment as a follower generators, which continuously to the wheels 10 are coupled. You can, for example, be designed so that they rotate in the inactivated state almost without resistance with the wheels and not slow them down. Only at the time of their activation, a small excitation current can be applied to the generators, which activates them as generators and start generating electrical energy. In another embodiment, it is quite possible to run the generators continuously, and only in the case of activation, the line contact to the heater 4 produce and thus close a consumer circle.

Thus, for example, a simple control either by the connection of the consumer in the form of the heater 4 or by applying an excitation current to the generators.

In 3 is now a plan view of a motor vehicle 1 shown in which the drive means 2 again as an internal combustion engine 5 is designed. Additionally is on a front axle 15 of the motor vehicle 1 as an energy converter 11 an electric motor 16 arranged. The structure of the catalyst 7 corresponds to that of the previously related to the 1 and 2 described catalyst 7 , In this embodiment, the control device is again via a control line 13 with the internal combustion engine 5 and can thus acquire measured values and parameters from this. In addition, the control device 14 via conduit 12 both with the electric motor 16 as well as with the heater 14 connected. Will now by the controller 14 detects a possibility for energy recovery, it activates the electric motor 16 as an energy converter 11 so this over the conduit 12 Provides energy in the form of an electrical current generated by the controller 14 to the heater 4 is forwarded and there for heating of the exhaust system 3 flowing exhaust gas 6 is being used. The vehicle shown here corresponds essentially to a so-called hybrid vehicle, in which the drive energy is initially generated in an internal combustion engine and partly directly from this to the wheels 10 is transmitted. In other driving conditions, that is due to the internal combustion engine 5 generated energy cached and then via the electric motor 16 to the wheels 10 transfer. In such a hybrid vehicle, the present invention can also be advantageously applied as previously shown.

In 4 is now a plan view of another possible embodiment of a motor vehicle 1 represented, which is suitable for carrying out the method according to the invention. Again, this is the drive means 2 again as an internal combustion engine 5 executed. Both at the front axle 15 as well as on a rear axle 17 There is one electric motor each 16 , Both electric motors 16 are as energy converters 11 available. Unlike the in 3 In the embodiment shown, the control device 14 so that in the case of energy recovery electrical energy from two drive axles 15 . 17 receive. In addition, however, this embodiment also has an energy storage 18 , which is formed with several so-called supercapacitors. The control device 14 Thus, it can be adapted particularly well to complex driving conditions and vehicle states, in particular states of the electrical system. So it is possible, for example, by the electric motors 16 provided electrical energy, which is obtained in the case of energy recovery, optionally in the heater 4 or for intermediate storage in the energy storage 18 initiate. The state of energy recovery is then ended, and by the energy converters 11 no more electrical energy provided, so can the energy stored in the supercapacitors of the cache 18 optionally for driving the electric motors 16 or for heating the heater 4 be used. When heating the heater 4 it is then possible in a subsequent example full load operation of the internal combustion engine 5 to purify the exhaust gases that occur without great delay at high temperatures. The exhaust system 3 and in particular the catalyst 7 can so by means of energy storage 18 cached energy or by the energy converter 11 provided energy directly in a new attack of exhaust gases unfold its full effect again and does not need to be heated first, what would otherwise be required additional external heating energy or a longer period of hot exhaust gases, in which then only a partial or poor exhaust gas purification is achieved. It will, as with the two line means 12 indicated, the recovered energy in parallel with the energy storage 18 and the heater 4 fed.

Incidentally, the present invention is not limited to the illustrated embodiments. In the context of the invention, it is quite possible to form the illustrated arrangements of energy converters, control devices and heaters within the exhaust system in numerous variants without departing from the inventive concept. For example, instead of the one heater, a plurality of heaters may be used. In addition, as already indicated, different numbers of energy converters 11 and energy storage 18 , as well as different types of consumers, by the controller 14 Consideration.

1

motor vehicle

2

drive means

3

exhaust system

4

heater

5

internal combustion engine

6

exhaust

7

catalyst

8th

Vehicle rear

9

honeycombs

10

wheel

11

energy converters

12

conduit means

13

control line

14

control device

15

Front

16

electric motor

17

rear axle

18

energy storage

Claims (8)

Method for operating a motor vehicle ( 1 ), which as components a drive means ( 2 ), an exhaust system ( 3 ) for exhaust gases ( 6 ) of the drive means ( 2 ) with at least one heating device ( 4 ) and at least one energy converter ( 11 comprising at least the following steps: (a) detecting a possibility for energy recovery, (b) activating the at least one energy converter ( 11 ), (c) supplying the energy from the at least one 11 ) recovered energy to the heater ( 4 ), (d) operating the heating device ( 4 ) for heating the exhaust gas ( 6 ) with the recovered energy, and (e) detecting an end to the possibility of energy recovery, after which the energy converter ( 11 ) and the provision of the recovered energy is stopped. Method according to the preceding claim, wherein this at least at a partial load of the drive means ( 2 ) or below an exhaust gas minimum temperature. Method according to one of the preceding claims, wherein steps (a) to (e) are performed by a control device ( 14 ). Method according to one of the preceding claims, wherein by a control device ( 14 ) continuously at least one energy absorption capability or an energy release capability of at least one energy storage device ( 18 ) or a consumer ( 4 ) is monitored. Method according to one of the preceding claims, wherein step (b) by means of at least one electric motor ( 16 ) or generator is running. Method according to one of the preceding claims, wherein for carrying out step (d) as a heating device ( 4 ) at least one electrically heatable honeycomb body ( 9 ) is used. Method according to one of the preceding claims, wherein while the step (d) an exhaust gas mass flow is at least partially recycled. Motor vehicle ( 1 ) comprising at least one drive means ( 2 ) and an exhaust system ( 3 ) with at least one controllable heating device which can be brought into contact with exhaust gas ( 4 ), in which at least the heating device ( 4 ) with a control device ( 14 ) arranged to carry out a method according to one of the preceding claims.