DE102019202560A1 - EXHAUST GAS AFTER-TREATMENT SYSTEM AND METHOD, VEHICLE AND METHOD OF OPERATING A VEHICLE - Google Patents

Abstract

A system for exhaust gas aftertreatment comprises an exhaust gas catalytic converter with a gas inlet, the exhaust gas catalytic converter being set up to receive exhaust gas from an internal combustion engine at the gas inlet and to carry out a catalytic treatment of the exhaust gas, an exhaust gas line coupled to the gas inlet for connecting the gas inlet to an outlet of the internal combustion engine, a gas tank for storing fuel gas, an air tank for storing compressed air, and a gas burner having an inlet coupled to the air tank and the gas tank and an outlet coupled to the exhaust pipe upstream of the gas inlet of the catalytic converter. The gas burner is configured to generate a hot gas flow by burning fuel gas obtained from the gas tank with compressed air obtained from the air tank in the gas burner.

Description

Technical area

The present invention relates to a system for exhaust gas aftertreatment, particularly when operating an internal combustion engine of a motor vehicle, e.g. of a diesel engine. The present invention further relates to a vehicle such as a car, a bus or a truck. The present invention also relates to a method for operating a vehicle and a method for exhaust gas aftertreatment.

background

An exhaust gas catalytic converter is an exhaust emission control device that converts toxic gases and pollutants in the exhaust gas of an internal combustion engine into less toxic or non-toxic substances by catalyzing a redox reaction (a reduction process and an associated oxidation process). Catalytic converters are particularly used in internal combustion engines that run on either gasoline (petrol) or diesel, including lean burn engines, but also in kerosene heaters, stoves, and so on. Other uses of catalytic converters are known in gas engines, for example in liquid gas engines or pressurized natural gas engines.

Selective Catalytic Reduction (SCR) is a well-known technique used in catalytic converters in which nitrogen oxides, referred to as NOx, are converted into diatomic nitrogen and water with the aid of a catalyst. A gaseous or liquid reducing agent, e.g. Anhydrous ammonia, aqueous ammonia solution or urea is fed to an exhaust gas stream and absorbed on the catalyst. SCR catalytic converters require a certain temperature for perfect operation, so that the catalytic reaction is typically only initiated at temperatures between 200 ° C and 250 ° C. The SCR catalytic converter is normally heated by the exhaust gas flowing through it. For this reason, under certain circumstances, such as a cold start or low-load operation of the engine, for example when idling, it can take a relatively long time to heat up the SCR catalytic converters and thus until the NOx emissions are efficiently reduced or this is not possible at all without additional support .

Efforts are being made to improve the performance of SCR or other catalysts during the warm-up phase. For example, describes the EP 2 687 694 A1 to provide an ozone generator configured to generate ozone which is injected into an exhaust line of an engine upstream of an SCR catalyst. The idea behind this approach is to convert NO contained in NOx into NO ₂ with the help of ozone. NO ₂ is highly reactive and can be converted to N ₂ in a chemical reaction with urea in the SCR, even if the exhaust gas temperature is low.

The WO 2016/113045 A1 describes a further approach to improve the performance of an exhaust gas catalytic converter during the heating phase, in which compressed air of an air supply system of a vehicle is fed into an exhaust gas section upstream of the exhaust gas catalytic converter. This can lead to an exothermic reaction in the catalytic converter if there is excess air. The excess air accelerates the reaction and thus accelerates the heating of the catalytic converter, even if the exhaust gas temperatures are relatively low.

Disclosure of the invention

One of the ideas of the invention is to find solutions for more efficient heating of catalytic converters.

The present invention relates to a system for exhaust gas aftertreatment according to claim 1, a vehicle according to claim 10, a method for operating a vehicle according to claim 12 and a method for exhaust gas aftertreatment according to claim 13.

Advantageous embodiments of the present invention emerge from the further subclaims and from the following description with reference to the figures of the drawing.

A first aspect of the invention relates to a system for exhaust gas aftertreatment with an exhaust gas catalytic converter with a gas inlet, the exhaust gas catalytic converter being configured to receive exhaust gas from an internal combustion engine at the gas inlet and to carry out a catalytic treatment of the exhaust gas, an exhaust gas line coupled to the gas inlet for connecting the gas inlet with an outlet of the internal combustion engine, a gas tank for storing fuel gas and an air tank for storing compressed air.

The exhaust line can have an inlet which is provided for coupling to or for connection to the outlet of the internal combustion engine, and an outlet which is coupled to or connected to the gas inlet of the catalytic converter. The exhaust pipe can be designed, for example, as a duct or pipe structure, with further components being able to be part of this duct or pipe structure or to form these.

The gas tank is designed to store fuel gas in a gaseous or liquid state, in particular at a pressure that is greater than the ambient pressure. The gas tank can be made of metal, for example. In a similar way, the air tank is set up to store compressed air at a predetermined pressure which is greater than the ambient pressure, for example at a pressure in a range between 5 bar and 15 bar. The air tank can be formed from metal, for example.

The system further comprises a gas burner having an inlet coupled to the air tank and the gas tank and an outlet coupled to the exhaust line upstream of the gas inlet of the catalytic converter, the gas burner for generating a hot gas stream by burning fuel gas obtained from the gas tank with the fuel gas obtained from the air tank Compressed air is set up in the gas burner. The outlet of the gas burner is coupled to the exhaust line at a point between the inlet and the outlet of the exhaust gas line and thus with respect to the internal combustion engine upstream of the exhaust gas catalytic converter. By feeding the hot gas flow generated by the gas burner into the exhaust line upstream of the exhaust gas catalytic converter, the exhaust gas catalytic converter is heated by the hot gas flow.

According to a second aspect of the invention, a vehicle is provided with an internal combustion engine, with a system for exhaust gas aftertreatment according to the first aspect of the invention, wherein the exhaust line is coupled to an outlet of the internal combustion engine, and with a compressed air system with a reservoir of compressed air, wherein the Reservoir forms an air tank for the exhaust gas aftertreatment system. The vehicle is thus a motor vehicle, e.g. a car, a bus or a truck, a reservoir of a compressed air system of the vehicle being used as the air tank of the exhaust gas aftertreatment system.

A third aspect of the invention relates to a method for operating a vehicle according to the second aspect of the invention. The method comprises generating a flow of hot gas by burning fuel gas with compressed air in the gas burner, introducing the flow of hot gas into the exhaust line and starting the internal combustion engine when a start condition is met.

According to this aspect, the catalytic converter is heated by means of a hot gas flow that is generated by the gas burner before the internal combustion engine is started. For example, this heating can be carried out during a phase in which supply air to the internal combustion engine is pretreated. This phase can last for example in about 2 seconds to 15 seconds.

According to a fourth aspect of the invention, a method for exhaust gas aftertreatment is provided, the method comprising generating a hot gas flow by burning fuel gas with compressed air in a gas burner, heating exhaust gas from an internal combustion engine by introducing the hot gas flow into the exhaust gas and feeding the exhaust gas into comprises a gas inlet of an exhaust gas catalytic converter for carrying out a catalytic treatment of the exhaust gas.

The method according to this aspect of the invention can for example be carried out with the aid of a system according to the first aspect of the invention and / or in a vehicle according to the second aspect of the invention. It is also possible to carry out the method according to this aspect of the invention as part of the method according to the third aspect of the invention. For example, the method steps according to this aspect of the invention can be carried out when the internal combustion engine has been started because the temperature detected at the gas inlet of the catalytic converter has reached the predetermined temperature threshold value. In this configuration, the method steps according to the fourth aspect of the invention can be carried out until the temperature detected at the gas inlet of the exhaust gas catalytic converter has reached a second predetermined temperature threshold value, for example a light-off temperature of the exhaust gas catalytic converter.

It is one of the ideas of the present invention to provide a gas burner specifically for generating a hot gas flow which is then used to heat the exhaust gas aftertreatment components, especially the catalytic converter, e.g. an SCR device, can be used.

As a result, the working temperature of the catalytic converter and the other components of the exhaust aftertreatment system (EATS) can be reached significantly faster than in conventional arrangements. In particular, the light-off temperature of the catalytic converter, that is to say the temperature at which the catalytic reduction is initiated within the catalytic converter, can be reached significantly earlier. A gas burner that is able to burn gaseous fuels offers the advantage that gaseous fuels, such as natural gas, usually burn with low particle emissions and NOx emissions. Furthermore, gaseous fuels are usually available at low prices.

By using a gas burner it is even possible to heat the EATS before starting the engine. Indeed, the invention can be used to heat the aftertreatment system independently of the operation of the engine. As a result, the invention offers advantages with regard to emission values, in particular during a cold start phase of an engine. In particular for heavy-duty engines, which have a high thermal mass and an EATS with a high thermal mass, the emissions and the heating-up time can be reduced. Thus, new and stricter regulations for internal combustion engines, especially in the case of diesel engines, can be complied with. The present invention offers advantages in particular in cold climates and / or in winter, since heating power is available independently of electrical heating means, the latter often having a high demand for electrical energy.

Furthermore, the EATS can be implemented with a very compact design that requires only a minimal number of components, since the present invention can use compressed air from a reservoir of a compressed air system of the vehicle.

According to one embodiment of the EATS, the gas burner comprises a mixing section, which is configured to generate an air-fuel mixture by mixing fuel gas received from the gas tank with compressed air received from the air tank, and an ignition device for igniting the air-fuel mixture . That is, fuel gas stored in the gas tank and compressed air stored in the air tank are mixed in a volume of the gas burner, which structures such as e.g. has inclined plates that promote turbulence in a gas flow entering the volume via the inlet. The ignition device, e.g. an electric igniter is provided for initially igniting the air-fuel mixture by adding heat to the air-fuel mixture, e.g. by creating a spark.

According to one embodiment, the ignition device can be formed by a spark plug or by a piezo igniter. A spark plug such as is commonly used in internal combustion engines has the advantage that it is inexpensive and reliable. Piezo igniters offer the advantage that they can work independently of electrical systems, since the principle of piezo igniters is based on the generation of an arc due to sudden deformation of a piezoelectric material. This deformation can be achieved by mechanical components such as springs.

According to a further embodiment, the system additionally has an evaporator, which is set up to evaporate fuel gas stored in the gas tank. The fuel gas may be stored in the gas tank in a liquid state. The evaporator can be arranged in a supply line which connects the gas tank to the inlet of the gas burner. The evaporator can for example be a heating element, e.g. an electrical heating element for heating fuel flowing through the supply line.

According to one embodiment, the system further comprises a reducing agent injector, which is configured to inject reducing agent for catalytic reduction of the exhaust gas in the exhaust gas catalytic converter upstream of the exhaust gas catalytic converter into the exhaust gas line, and a mixing unit arranged in the exhaust gas line between the reducing agent injector and the gas inlet of the exhaust gas catalytic converter, which is configured to do so is to mix the reducing agent with the exhaust gas, wherein the outlet of the gas burner is coupled to the exhaust gas line upstream or downstream of the mixing unit. The reducing agent can be injected in gaseous and / or liquid form.

Coupling the outlet of the gas burner upstream of the mixing unit offers the advantage that the mixing unit is also heated with the aid of the hot gas flow generated by the gas burner. As a result, any liquid constituents present in the reducing agent are evaporated and the performance of the catalytic converter is thereby further improved. Coupling the outlet of the gas burner downstream of the mixing unit offers the advantage that the reducing agent is already mixed with the exhaust gas, so that both of these are heated together by the hot gas flow coming from the liquid fuel burner. Furthermore, the catalytic converter is heated up in a shorter time, since the hot gas flow is supplied directly in front of the catalytic converter.

According to one embodiment, the system further comprises an oxidation catalytic converter which is configured to carry out an oxidation treatment of the exhaust gas, wherein the oxidation catalytic converter is arranged upstream of the exhaust gas catalytic converter in the exhaust gas line, the outlet of the gas burner being coupled to the exhaust gas line upstream or downstream of the oxidation catalytic converter. The oxidation catalytic converter can optionally have a particle filter.

Coupling the outlet of the gas burner upstream of the oxidation catalytic converter, e.g. between the inlet of the exhaust line and the oxidation catalytic converter, offers the advantage that the oxidation catalytic converter and other optional components, such as the mixing unit, arranged downstream of the oxidation catalytic converter are also heated. On the other hand, the coupling of the outlet of the gas burner downstream of the oxidation catalyst, for example between the oxidation catalyst and the optional mixing unit or between the optional mixing unit and the catalytic converter, reduces the time required to heat the catalytic converter to a predetermined temperature.

According to one embodiment, the system has a distributor which is set up to selectively couple the outlet of the gas burner to a specific point in the exhaust gas line. For example, the distributor can be set up to optionally couple to the exhaust line between the exhaust gas catalytic converter and the mixing unit, between the mixing unit and the oxidation catalytic converter or upstream of the oxidation catalytic converter. In a method according to the third or fourth aspect of the invention, the distributor can, for example, first couple the outlet of the gas burner to a point located directly at the gas inlet of the catalytic converter in order to quickly heat up the catalytic converter. The outlet of the gas burner can then be coupled to the exhaust line between the mixing unit and the oxidation catalytic converter or upstream of the oxidation catalytic converter. Furthermore, the point at which the outlet of the gas burner is coupled to the exhaust line can depend on the ambient temperature. For example, at high ambient temperatures it can be sufficient to couple the outlet of the gas burner to the exhaust gas line upstream of the oxidation catalytic converter in order to reach a predetermined temperature at the gas inlet of the exhaust gas catalytic converter within a predetermined time. On the other hand, at low ambient temperatures it can be more favorable to couple the outlet of the gas burner to the exhaust line at a point directly at the gas inlet of the exhaust gas catalytic converter in order to heat up the exhaust gas catalytic converter quickly within the predetermined time. Thus, the flexibility of the system is improved with the aid of the distributor.

According to one embodiment, the system has a control device which is set up to regulate the operation of the gas burner according to at least one of a start command, a temperature at the gas inlet of the catalytic converter and an oxygen content in the exhaust gas at the gas inlet of the catalytic converter. The control device can be implemented as a processor, a microprocessor, an ASIC, an FPGA or a similar processing device. The control device is set up to generate control commands which cause control structures or devices of the gas burner to be actuated in order to operate the gas burner. The control structures can be formed by inlet valves that connect the gas tank and the air tank to the inlet of the gas burner, and / or the ignition device or similar devices.

The start command can be, for example, an electrical signal provided by the engine or another device of the vehicle, which signal indicates that the ignition of the vehicle is switched on. Optionally, the start command can be used to implement a control in that it triggers operation of the gas burner for a predetermined period of time with a predetermined release of heat. The temperature and the oxygen content at the gas inlet can be used, optionally in connection with the start command, in order to implement a regulation, the control device regulating the operation of the gas burner in order to vary the temperature and / or the oxygen content at the gas inlet in such a way that a predetermined Temperature and / or a predetermined oxygen content is achieved at the gas inlet.

The control device can also be configured to regulate the operation of the gas burner with regard to initial ignition and / or with regard to the release of heat. For example, a ratio of compressed air and fuel gas, which are supplied from the air tank and from the gas tank to the inlet of the gas burner, can be varied according to a temperature and / or an oxygen content in the exhaust gas at the gas inlet of the catalytic converter and / or another operating condition, in particular according to thermodynamic State variables that are detected at the gas inlet of the catalytic converter or in the exhaust pipe.

According to one embodiment of the vehicle, the compressed air system is set up to supply compressed air to a brake system of the vehicle. For example, the reservoir can be connected via supply lines to a brake actuator of a brake system, for example to a wheel brake cylinder, and corresponding control structures such as valves and flaps. Such structures are typically integrated into heavy-duty vehicles such as trucks, buses or tractors. This means that the EATS can be easily integrated into vehicles.

According to one embodiment, the vehicle has a control device which is set up to regulate an air-fuel ratio in the internal combustion engine. Functions of the EATS control device described above are preferably integrated into this control device. This further improves the ability to integrate the EATS into the vehicle.

According to one embodiment of the method according to the third aspect of the invention, the start condition is predetermined by a Time lapse or defined by a predetermined temperature threshold. That is, the internal combustion engine is started after the exhaust gas catalytic converter has been heated by the gas burner for a predetermined period of time, for example for a time in a range between 2 seconds and 10 seconds, or after a predetermined temperature threshold value has been reached at the gas inlet of the catalytic converter. The gas burner can in particular be operated with a control or regulation for generating the start condition at the gas inlet.

In a closed-loop control, the method can include detecting a temperature at the gas inlet of the exhaust gas catalytic converter, for example by means of a temperature sensor, and starting the internal combustion engine when the detected temperature is equal to or greater than the predetermined temperature threshold value.

Further optionally, the temperature at the gas inlet of the exhaust gas catalytic converter can be recorded independently of a regulation or control of the gas burner. In particular, the method can include detecting a temperature at the gas inlet of the catalytic converter and generating a hot gas flow by burning fuel gas with compressed air in the gas burner if the detected temperature is less than the temperature threshold value. That is, if it is determined that the starting condition already exists before the engine is started, e.g. because the motor was switched off a short time beforehand, heating is not required and the burner is therefore not operated.

According to one embodiment of the method according to the fourth aspect of the invention, reducing agent is injected into the exhaust gas by means of a reducing agent injector for catalytic reduction in the exhaust gas catalytic converter, the reducing agent being injected upstream or downstream of the hot gas flow of the gas burner. The reducing agent can be urea, for example.

According to a further embodiment, compressed air is fed to the gas burner at a pressure in a range between 5 bar and 15 bar. The fuel gas can be supplied to the gas burner at the same pressure. By using pressures above ambient pressure, the hot gas flow generated by the gas burner can be fed to the exhaust line at a relatively high pressure. This increases the flow rate in the exhaust pipe, which advantageously improves the heat transfer and thus accelerates the heating of the exhaust gas catalytic converter.

The features described herein for the EATS and the vehicle are also disclosed for the methods according to the third and fourth aspects of the invention, and vice versa.

A “fuel gas” used in the context of the present disclosure is a combustible material which assumes a gaseous state under ambient conditions. Ambient conditions are standard temperature and pressure (STP), i.e. 0 degrees Celsius (° C) and 1013.25 hectopascals (hPa). The fuel gas can comprise or be, for example, methane, propane, butane, a mixture of these, or natural gas.

Figure list

• 1 zeigt schematisch ein Fahrzeug mit einem System zur Abgasnachbehandlung gemäß einem Ausführungsbeispiel der Erfindung.
• 2 zeigt schematisch einen Gasbrenner wie er in einem System zur Abgasnachbehandlung gemäß einem Ausführungsbeispiel der Erfindung verwendet wird.
• 3 zeigt schematisch ein System zur Abgasnachbehandlung gemäß einem weiteren Ausführungsbeispiel der Erfindung.
• 4 zeigt schematisch ein System zur Abgasnachbehandlung gemäß einem weiteren Ausführungsbeispiel der Erfindung.
• 5 zeigt schematisch ein System zur Abgasnachbehandlung gemäß einem weiteren Ausführungsbeispiel der Erfindung.

The accompanying figures are intended to provide a further understanding of the invention and form part of the present disclosure. They illustrate embodiments of the invention and, together with the description, serve to explain principles and concepts of the invention. Other embodiments of the invention and many of the recited advantages of the invention will become apparent in view of the following detailed description. The elements of the drawings are not necessarily shown to scale with one another. In the figures, the same reference symbols denote the same or functionally identical elements, unless otherwise stated.

• 1 schematically shows a vehicle with a system for exhaust gas aftertreatment according to an embodiment of the invention.
• 2 shows schematically a gas burner as it is used in a system for exhaust gas aftertreatment according to an embodiment of the invention.
• 3 shows schematically a system for exhaust gas aftertreatment according to a further embodiment of the invention.
• 4th shows schematically a system for exhaust gas aftertreatment according to a further embodiment of the invention.
• 5 shows schematically a system for exhaust gas aftertreatment according to a further embodiment of the invention.

While specific embodiments are illustrated and described herein, it will be apparent to those skilled in the art that a variety of alternative and / or equivalent implementations can be substituted for the specific embodiments shown and described without departing from the scope of the present invention. In general, the application covers any adaptations or variations of the specific exemplary embodiments described herein.

Detailed description of exemplary embodiments

1 shows schematically a vehicle 100 with an internal combustion engine 101 , like a diesel engine, and a system 10 for exhaust aftertreatment (EATS). As in 1 shown shows the vehicle 100 also a compression or compressed air system 102 with a reservoir 104 which stores compressed air.

The motor 101 drives a drive shaft 105 which in turn has at least one axis 106 , 107 of the motor 100 drives. About the rotation of the axes 106 , 107 into a translational movement of the vehicle 100 to convert are wheels W. to the axles 106 , 107 coupled, as symbolically in 1 is shown.

The reservoir 104 can be implemented as a tank which is set up to store air, for example, at a pressure in a range between 5 bar and 15 bar. The compressed air system 102 has pneumatic lines 108 , which are coupled to the reservoir, to take air from the reservoir 104 to different places in the vehicle 100 to direct.

Furthermore, the vehicle can 100 have a braking system, which in 1 symbolically as a block 103 is shown. The braking system 103 is set up to do the wheels W. to apply a frictional force to the vehicle 100 to break. The braking system 103 can for example have pneumatic actuators (not shown). The braking system 102 can thus through the pneumatic line 108 to the compressed air system 102 be coupled, as shown schematically in 1 is shown. General is the compressed air system 102 set up the braking system 103 to supply the vehicle with compressed air.

The in 1 engine shown as an example 101 is with an air inlet 15a for supplying fresh, cooled air to the engine 101 via a turbocharger 17th and intercooler 16 coupled. The motor 101 pushes exhaust gas through an exhaust pipe 15th from that after passing through a turbine of the turbocharger at an outlet 15b of the engine.

The system 10 is set up by the internal combustion engine 101 of the motor vehicle 100 to purify emitted exhaust gas. As in 1 shown as an example, the system 10 have a number of exhaust gas aftertreatment devices, including an optional oxidation catalyst and an optional diesel particulate filter (which are shown in 1 both under the reference number 19th are summarized), an optional reducing agent injector 11 , an optional mixing unit 12 and a catalytic converter 2 , which can for example be a device for selective catalytic reduction (SCR). Furthermore, the system 100 a gas burner 1 , a gas tank 3 and an air tank 4th on which by the reservoir 104 of the compressed air system 102 can be formed.

As in 1 shown by way of example is a gas inlet 2a of the catalytic converter 2 via an exhaust pipe 20th to an outlet 15b of the motor 101 coupled. In particular, there is an inlet 21st the exhaust pipe 20th to the outlet 15b of the motor 101 and an outlet 22nd the exhaust pipe 20th to the gas inlet 2a of the catalytic converter 2 coupled. That is, in the engine 101 generated exhaust gas is the exhaust pipe 20th over the inlet 21st and flows through the exhaust pipe 20th to the outlet 22nd the exhaust pipe 20th where there is the gas inlet 2a of the catalytic converter 2 is fed. One direction of flow is thus from the inlet 21st the exhaust pipe 20th to the inlet 2a of the catalytic converter 2 Are defined.

As in 1 shown, the optional oxidation catalyst 19th in the exhaust pipe 20th right at the entrance 21st be arranged, that is, upstream of the catalytic converter 2 . The oxidation catalyst 19th can be designed in a conventional manner and is set up to carry out an oxidation treatment of the exhaust gas, for example to convert unburned hydrocarbons into carbon dioxide and water.

The optional reducing agent injector 11 is upstream of the catalytic converter 2 to the exhaust pipe 20th coupled, preferably between the catalytic converter 2 and the oxidation catalyst 19th , as exemplified in 1 shown. The injector 19th is set up for the catalytic reduction of the exhaust gas within the exhaust gas catalytic converter 2 Reducing agent upstream of the catalytic converter 2 into the exhaust pipe 20th inject. The reducing agent is used in the usual way as a reducing partner in the catalytic process within the SCR catalytic converter 2 . For example, the SCR can catalytic converter 2 have a catalytically active substrate which is arranged between an entry surface and an exit surface (not shown). The substrate can, for example, comprise a ceramic monolith in the usual way, for example with honeycomb structures which form a large number of catalytically active subchannels through which the exhaust gas is passed for catalytic reduction.

The mixing unit 12 is optional to improve the mixing of the reducing agent, for example urea, and that in the exhaust line 20th flowing exhaust gas provided. The mixing unit 12 is therefore arranged downstream of a point where the injector 11 to the exhaust pipe 20th is coupled, as exemplified in 1 is shown.

The gas tank 3 is a tank or container that is able or is set up to store fuel either in a liquid or in a gaseous state, especially at a pressure that is greater than the ambient pressure, e.g. a pressure in a range between 5 bar and 15 bar. For example, the gas tank 3 be a metal tank of any shape. A combustible material that is gaseous at ambient pressure and temperature, such as natural gas, can be used as fuel. The gas tank 3 can store liquid gas or compressed natural gas, for example.

The gas burner 1 is in 2 shown in more detail. The gas burner 1 has an inlet 1a attached to the gas tank 3 and the air tank 4th is coupled, and an outlet 1b on that to the exhaust pipe 20th is coupled. The gas burner 1 a combustion chamber 7th on. Optional includes the gas burner 1 a mixing section 5 and an igniter.

The inlet 1a can flow control devices such as a first valve 23 and a second valve 24 have, as for example in 2 shown. The flow control devices are set up to vary a fluid volume flow. In particular, the first valve couples 23 the gas tank 3 to the gas burner 1 and the second valve 23 couples the air tank 4th or the reservoir 104 to the gas burner 1 . In the gas tank 3 stored fuel gas and in the air tank 4th stored compressed air can enter the combustion chamber 7th where the fuel gas is burned with the compressed air to create a hot gas stream that flows at the outlet 1b of the gas burner 1 provided.

As shown schematically in 2 is shown, the mixing section 5 adjacent to the inlet 1a be arranged and serves to generate an air-fuel mixture by mixing the gas tank 3 received fuel gas and that from the air tank 4th obtained compressed air. For example, a plurality of metal sheets (not shown) can be arranged in the mixing section.

The igniter 6th serves for the initial ignition of the fuel-air mixture in the combustion chamber 7th . The igniter 6th can for example be formed by a spark plug or a piezoelectric igniter.

As in 1 shown schematically are the gas tank 3 and the air tank 4th each with the inlet 1a of the gas burner, for example via supply lines. Optionally, a gas evaporator 8th which is set up for this in the gas tank 3 to vaporize stored fuel gas in a supply line between the gas tank 3 and the inlet 1a of the gas burner 1 be arranged. The evaporator 8th can be implemented as an electric heater, for example.

Again referring to 2 compressed air and the fuel present in gaseous state are fed to the burner 1 over the inlet 1a fed, optionally in the mixing section 5 premixed and the fuel is mixed with air in the combustion chamber 7th burned. As a result, a hot gas stream flows at the outlet 1b of the gas burner 1 from the combustion chamber 7th out.

The outlet 1b of the gas burner 1 is to the exhaust pipe 20th coupled. As exemplified in 1 shown can be the outlet 1b of the gas burner 1 directly adjacent to the gas inlet 2a of the catalytic converter 2 to the exhaust pipe 20th be coupled, for example between the optional mixing unit 12 and the gas inlet 2a of the catalytic converter 2 . General is the outlet 1b of the burner 1 upstream of the gas inlet 2a of the catalytic converter 2 to the exhaust pipe 20th coupled. This allows hot gas upstream of the catalytic converter 2 the exhaust pipe 2 fed and through the catalytic converter 2 be directed. Thus, the catalytic converter 2 can be heated even when a temperature of the exhaust gas is low or when there is no exhaust gas flow from the engine 101 is present, e.g. because the engine 101 is turned off.

Alternatively, the outlet 1b of the burner 1 upstream of the mixing unit 12 to the exhaust pipe 20th be coupled, as exemplified in the 3 and 4th shown. Optionally, the outlet 1b of the burner between the mixing unit 12 and the oxidation catalyst 10 to the exhaust pipe 20th be coupled, that is, downstream of the oxidation catalyst 19th and upstream of the mixing unit 12 , as in 3 shown. 4th shows an example that the outlet 1b of the burner 1 upstream of the oxidation catalyst 19th to the exhaust pipe 20th is coupled, that is, between the oxidation catalyst 19th and the inlet 21st the exhaust pipe 20th . General is the outlet 1b of the burner 1 upstream of the gas inlet 2a of the catalytic converter 2 to the exhaust pipe 20th coupled.

This in 5 system shown 10 differs from the one in 1 system shown 10 by having it a distributor 9 having. The distributor 9 is to the outlet 1b of the burner 1 coupled and has different distributor outlets 9b , 9c , 9d on. A first distributor outlet 9b is between the catalytic converter 2 and the mixing unit 12 to the exhaust pipe 20th coupled. A second distributor outlet 9c is between the mixing unit 12 and the oxidation catalyst 19th to the exhaust pipe 20th coupled. A third distributor outlet 9d is upstream of the oxidation catalyst 19th to the exhaust pipe 20th coupled. The distributor 9 can a Have flap system (not shown) which is set up to optionally have a fluid line between the outlet 1b of the gas burner 1 and one of the manifold outlets 9b , 9c , 9d to manufacture. Thus is the distributor 9 set up the outlet 1b of the gas burner 1 optionally between the catalytic converter 2 and the mixing unit 12 , between the mixing unit 12 and the oxidation catalyst 19th or upstream of the oxidation catalyst 19th to the exhaust pipe 20th to pair.

Like this in 1 and the 3 to 4th is shown, a control device 13 for the system 10 and / or for the vehicle 100 be provided. The control device 13 can have a data memory, in particular a non-volatile data memory such as a hard disk or a flash memory, and a processor unit such as a CPU. Of course, the control device 13 can also be implemented as a microcontroller, as an ASIC, as an FPGA or similar. The control device 13 is functional with the gas burner 1 and optionally with the motor 101 of the vehicle 100 connected, for example via a wireless or wired data connection. The control device 13 is set up to generate control commands to various control devices of the system 10 and / or the motor. Furthermore, the control device 13 functional with different in the system 10 provided sensors be functionally connected, for example with a temperature sensor and / or a lambda sensor, which is at the gas inlet 2a of the catalytic converter 2 are provided.

The control device 13 is set up to operate the gas burner 1 according to at least one of a temperature at the gas inlet 2a of the catalytic converter 2 which is detected, for example, with the temperature sensor (not shown), and an oxygen content in the exhaust gas at the gas inlet 2a of the catalytic converter 2 , which is detected with the lambda sensor, for example. Additionally or alternatively, the control device 13 be set up to operate the gas burner 1 to be regulated according to a start condition. The start condition can be fulfilled, for example, when the control device detects a start signal, for example one from the engine 101 or another device of the vehicle 100 Electrical signal provided, which indicates that the ignition of the vehicle 100 is switched on.

In particular, the control device 13 set up to operate the gas burner 1 to regulate in relation to an initial ignition of the fuel gas. That is, the control device 13 can generate a command signal, which the ignition device 6th causes a spark to start burning the fuel in the gas burner 1 to initiate. The control device is additionally or alternatively 13 set up to operate the gas burner 1 to regulate in terms of heat release. For example, the control device 13 generate a command signal that controls the control equipment, e.g. the valves 23 , 24 , caused to vary the volume flow of the fuel and / or the compressed air. This also allows the air-fuel ratio to be varied.

The control device 13 can also be set up to use the optional distributor 9 to control. That is, the control device 13 can generate command signals which cause the valve system (not shown) of the distributor to open the outlet 1b of the gas burner 1 with one of the distributor outlets 9b , 9c , 9d connect to.

Furthermore, the control device 13 also be set up to operate the internal combustion engine 101 of the vehicle, for example an air-fuel ratio in the internal combustion engine 101 .

A method of operating the vehicle 100 and a method for exhaust gas aftertreatment is described below by way of example with reference to the vehicle 100 and the systems 10 as described above. In particular, the control device 13 to be set up the components of the system 10 and the vehicle 100 , especially the gas burner 1 and the engine 101 to initiate operation in accordance with the process steps described below.

The procedure for operating the vehicle 100 optionally has a detection of a temperature at the gas inlet 2a of the catalytic converter 2 on, for example by means of a temperature sensor (not shown). A hot gas stream is created by burning fuel gas from the gas tank 3 with compressed air from the air tank 4th or the reservoir 104 in the gas burner 1 generated. Optionally, the hot gas flow can only be generated if the detected temperature is less than a predetermined temperature threshold value or generally if a start condition is not met. To generate the hot gas flow, the control device 13 the valves 23 , 24 and the igniter 6th control accordingly. The hot gas flow is in the exhaust pipe 20th directed, in particular to one of the points of the exhaust pipe as in the 1 , 3 or 4th shown. If the detected temperature is equal to or greater than the predetermined temperature threshold value or another starting condition is met, the internal combustion engine is switched off 101 started. For example, the control device initiates 13 the combustion of an air-fuel mixture in the engine 101 .

The exhaust aftertreatment process can be performed while the engine is running 1001 runs, for example after a cold start of the engine 101 when the temperature at the gas inlet 2a of the catalytic converter 2 is still below a threshold value, in particular a light-off temperature of the catalytic converter 2 .

According to this method, a hot gas stream is generated by burning fuel gas with compressed air in the gas burner 1 generated as described above. The hot gas flow is fed to the exhaust gas by introducing it into the exhaust pipe 20th is passed to heat the exhaust gas from an internal combustion engine by means of the hot gas stream. The heated exhaust gas is via the exhaust pipe 20th to a gas inlet 2a of the catalytic converter 2 passed to perform a catalytic treatment of the exhaust gas. Catalytic reduction in the catalytic converter is optional 2 Reducing agent by means of the reducing agent injector 11 injected into the exhaust gas. As described above, the reducing agent is placed upstream or downstream of the hot gas of the gas burner 1 injected.

While the systems and methods mentioned herein have been described in connection with vehicles such as trucks or automobiles, respectively. However, the person skilled in the art can clearly and unambiguously understand that the systems and methods described herein can also be used for other objects which have an internal combustion engine.

The invention has been described in detail with reference to exemplary embodiments. However, it will be understood by those skilled in the art that changes can be made in these embodiments without departing from the principles and spirit of the invention, the scope defined in the claims, and their equivalents.

List of reference symbols

1

Gas burner

1a

Inlet of the gas burner

1b

Gas burner outlet

2

Catalytic converter

2a

Gas inlet of the catalytic converter

2 B

Gas outlet of the catalytic converter

3

Gas tank

4th

Air tank

5

Mixing section of the gas burner

6th

Ignition device

7th

Combustion chamber

8th

Gas vaporizer

9

Distributor

9c-d

Distribution outlets

10

Exhaust aftertreatment system

11

Reducing agent injector

12

Mixing unit

13

Control device

15th

Gas pipe

15a

Air inlet

15b

Outlet

16

Intercooler

17th

turbocharger

19th

Oxidation catalyst / particle filter

20th

Exhaust pipe

21st

Inlet of the exhaust pipe

22nd

Exhaust pipe outlet

23

first valve

24

second valve

100

Motor vehicle

101

Internal combustion engine

102

Compressed air system

103

Braking system

104

reservoir

105

drive shaft

106, 107

axes

108

Pneumatic line

W.

bikes

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 2687694 A1 [0004]
• WO 2016/113045 A1 [0005]

Claims (16)

System (10) for exhaust aftertreatment, with: an exhaust gas catalytic converter (2) with a gas inlet (2a), the exhaust gas catalytic converter (2) being set up to receive exhaust gas from an internal combustion engine (101) at the gas inlet (2a) and to carry out a catalytic treatment of the exhaust gas; an exhaust pipe (20) coupled to the gas inlet (2a) for connecting the gas inlet (2a) to an outlet (15b) of the internal combustion engine (101); a gas tank (3) for storing fuel gas; an air tank (4) for storing compressed air; and a gas burner (1) with an inlet (1a) coupled to the air tank (4) and the gas tank (3) and an outlet (1b) coupled to the exhaust pipe (20) upstream of the gas inlet (2a) of the catalytic converter (2), wherein the gas burner (1) is set up to generate a hot gas flow by burning fuel gas obtained from the gas tank (3) with compressed air obtained from the air tank (4) in the gas burner (1). System (10) Claim 1 wherein the gas burner (1) has a mixing section (5) adapted to generate an air-fuel mixture by mixing fuel gas obtained from the gas tank (3) with compressed air obtained from the air tank (4), and an ignition device (6) for igniting the air-fuel mixture. System (10) Claim 2 , wherein the ignition device (6) is formed by a spark plug or by a piezo igniter. System according to one of the preceding claims, additionally comprising: an evaporator (8) which is set up to evaporate fuel gas stored in the gas tank (3). System (10) according to one of the preceding claims, additionally comprising: a reducing agent injector (11) which is set up to inject reducing agent for the catalytic reduction of the exhaust gas in the exhaust gas catalytic converter (2) upstream of the exhaust gas catalytic converter (2) into the exhaust gas line (20); and a mixing unit (12) which is arranged in the exhaust gas line (20) between the reducing agent injector (11) and the gas inlet (2a) of the exhaust gas catalytic converter (2) and is configured to mix the reducing agent with the exhaust gas; wherein the outlet (1b) of the gas burner (1) is coupled to the exhaust pipe (20) upstream or downstream of the mixing unit (12). System (10) according to one of the preceding claims, additionally comprising: an oxidation catalytic converter (19) which is set up to carry out an oxidation treatment of the exhaust gas, wherein the oxidation catalyst (19) is arranged upstream of the exhaust catalyst (2) in the exhaust pipe (20), the outlet (1b) of the gas burner (1) upstream or downstream of the oxidation catalyst (19) to the exhaust pipe ( 20) is coupled. System (10) according to one of the Claims 1 to 4th , additionally comprising: a reducing agent injector (11) which is set up to inject reducing agent for the catalytic reduction of the exhaust gas in the exhaust gas catalytic converter (2) upstream of the exhaust gas catalytic converter (2) into the exhaust gas line (20); and a mixing unit (12) which is arranged in the exhaust gas line (20) between the reducing agent injector (11) and the gas inlet (2a) of the exhaust gas catalytic converter (2) and is configured to mix the reducing agent with the exhaust gas; an oxidation catalytic converter (19) which is set up to carry out an oxidation treatment of the exhaust gas, the oxidation catalytic converter (19) being arranged upstream of the exhaust gas catalytic converter (2) in the exhaust gas line (20); and a distributor (9) which is set up to connect the outlet (1b) of the gas burner (1) either between the exhaust gas catalytic converter (2) and the mixing unit (12), between the mixing unit (12) and the oxidation catalytic converter (19) or upstream of the oxidation catalytic converter (19) to be coupled to the exhaust pipe (20). System (10) Claim 7 , additionally comprising: a control device (13) which is set up to operate the gas burner (1) according to at least one of a start command, a temperature at the gas inlet (2a) of the catalytic converter (2) and an oxygen content in the exhaust gas at the gas inlet (2a ) of the catalytic converter (2). System (10) Claim 8 , wherein the control device (13) is set up to regulate the operation of the gas burner (1) in relation to an initial ignition and / or in relation to the heat emission. A vehicle (100) comprising: an internal combustion engine (101); a system (10) for exhaust gas aftertreatment according to any one of the preceding claims, wherein the exhaust line (20) is coupled to an outlet (15b) of the internal combustion engine (101); and a compressed air system (102) having a reservoir (104) of compressed air; wherein the reservoir (104) forms an air tank (4) of the system (10) for exhaust gas aftertreatment. Vehicle (100) after Claim 10 , wherein the compressed air system (102) is set up to supply compressed air to a brake system (103) of the vehicle (100). Method for operating a vehicle (100) according to Claim 10 or 11 comprising: generating a hot gas flow by burning fuel gas with compressed air in the gas burner (1); Introducing the hot gas stream into the exhaust line (20); and starting the internal combustion engine (101) when a starting condition is met. Procedure according to Claim 12 , wherein the start condition is defined by a predetermined time lapse or by a predetermined temperature threshold value. Method for exhaust aftertreatment, comprising: Generating a hot gas flow by burning fuel gas with compressed air in a gas burner (1); Heating exhaust gas from an internal combustion engine (101) by introducing the flow of hot gas into the exhaust gas; and Feeding the exhaust gas into a gas inlet (2a) of an exhaust gas catalytic converter (2) for carrying out a catalytic treatment of the exhaust gas. Procedure according to Claim 14 , additionally comprising: injecting reducing agent into the exhaust gas by means of a reducing agent injector (11) for catalytic reduction in the exhaust gas catalytic converter (2), the reducing agent being injected upstream or downstream of the hot gas flow of the gas burner (1). Procedure according to Claim 14 or 15th , the gas burner (1) being supplied with compressed air at a pressure in a range between 5 bar and 15 bar.

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