DE102021120364A1 - System and an associated method for the safe operation of a combustion gas supply of an internal combustion engine operated with a combustion gas, in particular during a cold departure - Google Patents

Abstract

The invention relates to a system and an associated method for the safe operation of a combustion gas supply of an internal combustion engine (14) operated with a combustion gas, the exhaust gas of which is discharged via an exhaust gas discharge device. It is provided that a combustion gas line (50) and/or at least one in the combustion gas line (50) integrated components of the combustion gas supply and an exhaust gas line (51) and/or at least one component integrated into the exhaust gas line (51) are positioned on their line routing sections at least over a specifiable section length with a specifiable distance from one another, so that the components from the exhaust gas line (51 ) and/or the at least one component integrated in the exhaust gas line (51) gives off convection heat in a heat transfer area to the combustion gas line 50 and/or to the at least one component integrated in the combustion gas line (50) and thus to the verb combustion gas is transferred in the combustion gas line (50).

Description

The invention relates to a system for the safe operation of a combustion gas supply of an internal combustion engine operated with a combustion gas, the exhaust gas of which is discharged via an exhaust gas discharge device.

As part of the energy transition, drives that can be operated with renewable energy sources are to be increasingly used. At the same time, the emission profile of the vehicles is to be improved. Natural gas or methane are suitable energy sources for this. In order to fully exploit the potential of these fuels and to keep vehicle costs low, monovalent concepts are essential.

In the case of natural gas vehicles, a cold run with CNG is critical, as the gas pressure regulator or other components such as injectors can ice up after just a few meters.

The hoses leading from the gas pressure regulator to the injection system are also critical in this environment. These are only permitted up to a certain lower temperature range, since otherwise their cold brittleness is no longer tolerable. In other words, during the expansion of the methane, in particular at high storage pressure and/or cold ambient temperatures, the temperature of the gas expanded when it is removed from the storage falls below a temperature value of -40°C. Below this value, the gas pressure regulator will ice up and cold brittle fractures will occur in the downstream gas lines between the gas pressure regulator and the injectors, and the injectors themselves may become blocked. Cold starts, especially in combination with high loads, favor these effects.

In particular, monovalent vehicles with natural gas or methane as an energy source should be able to be operated like conventional vehicles, for example with petrol, in the future. It is known to store gasoline in bivalent (natural gas/gasoline) fuel systems, so that the cold start and the cold run-down when gasoline is burned (no gas pressure regulation necessary) takes place until the fuel system is warm. However, this is not possible with monovalent system designs.

From the pamphlet DE10 2018 113 239 A1 a supply system for supplying a CNG or LNG fuel from a tank to a conversion device is known, the supply system having at least one line, a heating device and a gas pressure regulator, the line being connectable to the tank via a first end and via a second end end connected to the gas pressure regulator; at least the line being across the heater.

Next is from the DE 10 2018 118 755 A1 a device is known which comprises a fuel supply device and a fuel injection device which are arranged at least partially in an engine compartment and by means of which the gas is supplied to at least one combustion chamber of an internal combustion engine of the vehicle. Provision is made for at least one exhaust gas supply device of an auxiliary heating device to be assigned to the engine compartment, or for the auxiliary heating device and the exhaust gas supply device to be arranged in the engine compartment, with the exhaust gas supply device being used during operation by means of the exhaust gas flow of the auxiliary heating device flowing into the engine compartment for heating at least one of the fuel supply device and/or or component associated with the fuel injector.

The pamphlet DE 10 2018 118 755 A1 also discloses a guiding device for the targeted supply of the warm exhaust gas flow. At least one of the components is ensured by (exhaust gas flow) guide devices that are arranged at predeterminable positions in the engine compartment between the burner and the respective components.

In addition, the pamphlet describes DE 10 2009 036 669 A1 a power generation system that includes a drive unit in which at least one fuel gas is converted and from which an exhaust gas stream flows. It also includes a pressure tank for the fuel gas, with at least one storage volume and at least one valve device for providing the fuel gas for the drive unit. The at least one exhaust gas flow is in at least indirectly thermally conductive contact with the valve device.

Proceeding from this state of the art, the invention is based on the object of specifying a device and a method for safe operation, in particular when starting off cold, of a vehicle with an internal combustion engine that is operated with compressed gas.

The starting point of the invention is a system for the safe operation of a combustion gas supply of an internal combustion engine operated with a combustion gas, the exhaust gas of which is discharged via an exhaust gas discharge device.

According to the invention it is provided that a combustion gas line and / or at least one integrated into the combustion gas line component of the combustion gas supply and a The exhaust pipe and/or at least one component integrated in the exhaust pipe are positioned on their pipe routing sections at least over a specifiable section length with a specifiable distance from one another, so that the convection heat given off by the exhaust pipe and/or the at least one component integrated in the exhaust pipe is transmitted in a heat transfer area the combustion gas line and/or to the at least one component integrated in the combustion gas line and thus to the combustion gas in the combustion gas line, wherein the amount of heat that can be transferred can be influenced by a shielding device and/or separating device arranged in the heat transfer area of the specified common route length of the common line routing route.

According to the invention, the shielding device has means for influencing the amount of heat that can be transferred by convection between the combustion gas supply and the exhaust gas discharge device in the heat transfer region, with which the shielding device can be temporarily moved from an open position to a closed position and vice versa in relation to the environment.

According to the invention, it is further provided that the separating device has means for influencing the amount of heat that can be transferred by convection between the combustion gas supply line and the exhaust gas discharge device in the heat transfer area, with which the heat transfer area can be temporarily moved from a separating position to a non-separating position and vice versa through the separating device.

It is preferably provided that an exhaust manifold (as a component of the exhaust gas removal device) and/or the exhaust gas line of the exhaust gas removal device and the combustion gas line of the combustion gas supply, which form the heat transfer area formed with the shielding device and/or the separating device, are arranged in the engine compartment of the internal combustion engine.

In another preferred embodiment, it is provided that the exhaust gas line of the exhaust gas discharge device and the combustion gas line of the combustion gas supply, which form the heat transfer area formed with the shielding device and/or the separating device, are arranged in a vehicle floor or under a vehicle floor of a vehicle equipped with the system.

Furthermore, it is preferably provided in detail that the shielding device is designed as a thermal convection box that spatially encloses the heat transfer area between the combustion gas feed and the exhaust gas discharge device, with at least part of the thermal convection box being designed to be movable as a shielding element that can be temporarily moved from the open position to the closed position and can be brought in reverse.

The separating device is preferably designed in detail as a separating element that spatially separates the heat transfer area between the combustion gas feed and the exhaust gas discharge device, the separating element being temporarily moveable from a separating position to a non-separating position and vice versa.

In a preferred embodiment of the invention, it is provided that the separating device is integrated into the shielding device designed as a heat convection box.

The system is preferably configured with at least one shielding element of the shielding device and/or with at least one separating element of the separating device, wherein the at least one shielding element and the at least one separating element are assigned controllable actuators which set the open position and closed position or at least one intermediate position of the shielding device or the separating position and causes/cause non-separation position or at least one intermediate position of the separation device.

Furthermore, it is preferably provided that, in particular for process control, a pressure sensor is arranged in the combustion gas feed of the system, which determines the pressure in the combustion gas feed and a temperature sensor is arranged in the heat transfer area of the system, which determines the temperature in the heat transfer area and in the vicinity of the heat transfer area another temperature sensor is arranged, which determines a temperature in the environment.

The invention also relates to a method for the safe operation of a combustion gas supply of an internal combustion engine operated with a combustion gas, the exhaust gas of which is discharged via an exhaust gas discharge device, it being provided according to the invention that the shielding device temporarily moves from an open position to a closed position and vice versa and/or the separating device temporarily from a disconnected position is/are brought into a non-disconnected position and vice versa, the closed position and/or the non-disconnected position depending on an in the pressure measured during the combustion gas supply, which is greater than a predeterminable limit pressure and/or as a function of a temperature measured in the environment which is lower than a predeterminable limit temperature.

It is preferably provided that the closed position of the shielding device and/or the non-separating position of the separating device is only assumed when the pressure measured in the combustion gas supply is greater than the specified limit pressure and the temperature measured in the environment is lower than the specified limit temperature right

• 1 ein System zum sicheren Betrieb einer Verbrennungsgaszuführung einer mit einem Verbrennungsgas betriebenen Verbrennungskraftmaschine, deren Abgas über eine Abgasabführungseinrichtung abgeführt wird;
• 2A eine erfindungsgemäße Abschirmvorrichtung gemäß einer ersten Ausführungsvariante;
• 2B eine erfindungsgemäße Abschirmvorrichtung gemäß einer zweiten Ausführungsvariante in Kombination mit einer Trennvorrichtung;
• 2C eine erfindungsgemäße Abschirmvorrichtung gemäß einer dritten Ausführungsvariante; und
• 3 ein Blockschaltbild zur Verdeutlichung des Verfahrens zum sicheren Betrieb einer Verbrennungsgaszuführung einer mit einem Verbrennungsgas betriebenen Verbrennungskraftmaschine.

The invention is explained in detail below with reference to the figures. Show it:

• 1 a system for the safe operation of a combustion gas supply of an internal combustion engine operated with a combustion gas, the exhaust gas of which is discharged via an exhaust gas discharge device;
• 2A a shielding device according to the invention according to a first embodiment;
• 2 B a shielding device according to the invention according to a second embodiment variant in combination with a separating device;
• 2C a shielding device according to the invention according to a third embodiment; and
• 3 a block diagram to illustrate the method for safe operation of a combustion gas supply system operated with a combustion gas internal combustion engine.

A core idea of the solution according to the invention is that the exhaust gas flow (compare the block diagram in advance 1 ) of an exhaust gas discharge device 60 has a temperature level that is significantly higher than that of the environment. In addition, the exhaust pipe 51 of the internal combustion engine 41 consists of a thin metal tube which has excellent thermal conductivity, which leads to a high level of heat being released into the environment.

In particular, in the area of an exhaust manifold of the exhaust line 51 downstream of the internal combustion engine 41 directly at the outlet of the internal combustion engine 41, the temperature of the exhaust gas is high, so that a large amount of heat is transferred to the environment in the area of the exhaust manifold.

In the further course of the exhaust gas discharge device 60 or the exhaust gas line 51, the exhaust gas flow, in particular downstream of the oxidation catalytic converter for exhaust gas aftertreatment, also has a significantly higher temperature level than the environment.

In other words, the entire exhaust gas discharge device 60, in particular between the exhaust manifold and the outlet opening of the exhaust gas discharge device 60, in principle offers potential for using the heat otherwise released into the environment.

The routing of the exhaust gas discharge device 60 of the exhaust manifold in the engine compartment and the continuing exhaust gas line 51 of the exhaust gas discharge device 60 below a vehicle floor is carried out without further heat shielding from the environment.

The idea is first and foremost to use the heat to improve the conditions for a cold start of a vehicle with an internal combustion engine that is operated with compressed gas.

This idea according to the invention is first implemented by positioning a combustion gas line 50, which comes from a gas reservoir 10 of the vehicle and leads to a pressure reducer 21, over a predeterminable length of the line routing so close to the exhaust line 51, i.e. in close proximity to the exhaust line 51 is arranged that the heat given off by the exhaust pipe 51 or a component of the exhaust gas discharge device 60 is transferred to the combustion gas pipe 50 and thus to the gas in the combustion gas pipe 50 (and not to the environment).

Provision is made here for a possible minimum distance between the exhaust gas line 50 or the components arranged in the exhaust gas line 50 and the combustion gas line 50 to be maintained while complying with the technical regulations or legislation.

For clarity shows 1 a block diagram of an exemplary solution in which, in a simple configuration, an exhaust gas line 51 is arranged in close proximity to a combustion gas line 50 carrying combustion gas.

The 1 12 shows the internal combustion engine 41, which has a supply system for the combustion gas to the internal combustion engine 41, using the block diagram.

1 also shows a discharge system for the exhaust gas of the internal combustion engine 41, which comprises the exhaust manifold and an exhaust gas treatment system 60, which essentially consist of an exhaust pipe 51 and components of the exhaust gas aftertreatment system 60 arranged in the course of the exhaust pipe.

The exhaust manifold, which is arranged at the beginning of the exhaust gas discharge device 60 in the engine compartment, is not shown explicitly in the block diagram.

The combustion gas supply system comprises the storage tank 10, in particular the CNG storage tank and a shut-off valve 20 arranged in the combustion gas line 50 and the pressure reducer 21 arranged in the combustion gas line 50. Downstream of the storage tank 10 of the combustion gas is a pressure sensor 80 for detecting the pressure in or at the outlet of the storage tank 10 applied pressure PT provided which also prevails in the combustion gas line 50 substantially.

The combustion gas line 50 can be opened and closed with respect to the storage tank 10 via a shut-off valve 20 .

In the exemplary embodiment, a predeterminable length of the line routing sections of the combustion gas line 50 is provided between the shut-off valve 20 and the pressure reducer 21, which is arranged together with the exhaust line 51 in a shielding device 70 according to the invention, which is explained in more detail below.

The combustion gas line 50 is completed by the injection system 40 arranged downstream between the pressure reducer 21 and the internal combustion engine 41.

The overall system is further characterized in that a control unit 33 receives measurement signals from the pressure sensor 80 of the pressure PT of the combustion gas downstream of the storage tank 10, with a first temperature sensor 31 with the reference number 31 also measuring the temperature T1 within the shielding device 70 and a second temperature sensor with reference numeral 32 determines an ambient temperature T2.

These measured values are required to carry out the method described below, as will be explained below.

Depending on these measured values T1, T2, an actuator 71 of the shielding device 70 is controlled via the control unit 33, as will also be explained in more detail below.

Inside the shielding device 70, directional arrows are indicated on the combustion gas line 50 and the exhaust gas line 51, which indicate the respective direction of flow of the combustion gas in the combustion gas line 50 and the exhaust gas line 51, respectively.

In a preferred embodiment of the invention, it is provided that gas streams in the lines 50, 51 within the shielding device 70 are oriented in flow directions that correspond to the countercurrent principle of a heat exchanger. As is known, the countercurrent principle is more effective than the cocurrent principle with regard to the heat exchange, but this also means that the configuration in the cocurrent principle is fundamentally possible at the expense of less effectiveness.

The description already indicates that the shielding device 70 operates in a manner analogous to a heat exchanger, with the invention providing that the shielding device 70 has an open position I and a closed position II, as will be explained below.

The shielding device 70 according to the invention is therefore an openable or closable heat exchanger which is designed as a box, so that it is referred to as a heat convection box which, without material exchange, enables the exchange of heat from the exhaust pipe 51, which is warmer in terms of temperature level, to the opposite one in terms of temperature level the exhaust line 51 cooler combustion gas line 50 causes.

It is noted that the term "box" can also be replaced by the general term enveloping body, since the shielding device can have any other non-rectangular geometric shape that meets the requirements for an isolated or non-isolated position or the open position I or closed position II , as is made clear by the description. It is understood that the person skilled in the art will use the simplest possible form, which is why the invention is explained using the heat convection box.

The thermal convection box is characterized in that it can be opened (open in open position I = not shielded from the environment) or closed (closed in closed position II = shielded from the environment) so that it is a temporary shielding device 70 in the manner of a Heat convection box is, which is only temporarily in the open position I or the closed position II.

Depending on its position I or II, it is ensured that the heat given off by the exhaust pipe 51 is (mainly) transferred to the combustion gas pipe 50 and thus to the combustion gas and thus less to the environment.

Various design variants are provided for the design of the heat convection box, which in the exemplary embodiment is arranged in particular below the vehicle floor in the area of the planned route length in which the exhaust gas line 51 and the combustion gas line 50 are located together.

First variant:

According to 2A a control unit 33 controls the motor drive as an actuator 71 of a shielding element of the shielding device 70, the shielding element being a lower cover (facing the street) of the heat convection box, which is designed like a roller shutter or the like.

The heat convection box is in 2A shown schematically in a kind of top view, and includes according to 2A at least the lower lid and front and rear end walls, and left and right end walls, which together form the heat convection box. The upper end is formed by the underbody of the body, under which the exhaust gas treatment system 60 is arranged. The upper end can also be formed by an upper cover of the heat convection box.

In the heat convection box, the exhaust pipe 51 is in the predeterminable local proximity to the combustion gas pipe 50 carrying the combustion gas, an arrangement in one plane with the same distance to the underbody or in two planes with different distances to the underbody being possible.

Provision is made for the lower cover to open and close as required--as will be explained below--as illustrated by the arrow P2A, or to be opened and closed again only partially or in stages provided for this purpose. It goes without saying that the direction of the closing and opening movement can be chosen.

In the shielded closed position II, the heat is transferred by shielding the environment. The air inside the heat convection box heats up, and the heat is transferred from the exhaust gas duct 51 to the combustion gas duct 50 . It is clear that the effect is achieved particularly quickly when the exhaust pipe 51 has a high temperature level and/or the volume of the heat convection box is adapted to the desired heat transfer rate.

Second variant:

2 B shows another solution in another embodiment.

In this embodiment variant, control unit 33 controls at least one, preferably two, motor drives as actuators 71, with one of the motor drives being assigned a shielding element of shielding device 70 and the other motor drive being assigned a separating device 72 in the form of a separating element that separates the exhaust pipe 51 temporarily separates or does not separate from the combustion gas line 50 with regard to the possible heat transfer (if required), that is, heat transfer from the exhaust gas line 51 to the combustion gas line 50 is made possible.

The heat convection box is in 2 B again shown schematically in a kind of top view, and includes according to 2 B at least the lower lid and the upper and lower end walls, and the left and right end walls, which together form the heat convection box. The upper end is formed by the underbody of the body, under which the exhaust gas treatment system 60 is arranged. The upper end can also be formed by an upper cover of the heat convection box.

In the heat convection box, the exhaust pipe 51 is in the predeterminable local proximity to the combustion gas pipe 50 carrying the combustion gas, an arrangement in one plane with the same distance to the underbody or in two planes with different distances to the underbody being possible. The separating element is arranged between the exhaust gas line 51 and the combustion gas line 50, which separates or releases the lines 50, 51, as shown by the arrow P2B`, as required with regard to the possible heat exchange, in that the separating element moves in or out of the heat convection box to separate the lines. The partition member is disposed between the ducts 50, 51 in the axial direction of the exhaust gas duct 51 and the combustion gas duct 50. As shown in FIG.

The separating element is also used as required, it also being possible according to the invention for the separating element to move into or out of the heat convection box only partially or to the length provided for this purpose. In this respect, using the Separating element no open position of the heat convection box, but a disconnected position or a non-separated position of the lines 50, 51 within the heat convection box.

In the shielded closed position II, the heat is transferred by shielding the environment. The air inside the heat convection box heats up and the heat is transferred by convection and heat conduction in the combustion gas duct 50 from the exhaust gas duct 51 to the combustion gas duct 50 and finally to the combustion gas.

With regard to the shielding, the second embodiment variant provides that, as shielding elements, at least one of the end walls and/or at least one of the side walls can be opened and closed as required, as illustrated in the embodiment variant shown using the arrow P2B" of the at least one front end wall.

The front end wall selected in the exemplary embodiment can in turn be opened and closed again only partially or in stages provided for this purpose, analogously to the first embodiment variant. It goes without saying that the direction of the closing and opening movement can be chosen.

The actuation of the shielding elements, i.e. the separating element and at least one of the end walls and/or at least one of the side walls, can be carried out individually or in combination in parallel or one after the other in order to increase the heat transfer from the exhaust pipe 51 and the combustion gas pipe 50 with regard to the amount of heat to be transferred steer.

In the second embodiment variant, flaps can be opened or closed as shielding elements of the at least one end wall and/or the at least one side wall, or it is also conceivable that shielding elements in the manner of sliding doors form the end walls or side walls, which are designed to be closable and openable .

Third variant:

In a third embodiment variant, it is provided that the control unit 33 controls a motor drive as an actuator 71, which is assigned to at least one pivotable flap according to arrow P2C.

The heat convection box is in 2C shown schematically in a sectional view, where the sectional plane intersects the thermal convection box, the side walls discussed above, and the top and bottom lids.

The exhaust gas line 51 and the combustion gas line 50 are thus analogous to the embodiment variant in FIG 2 in and out of the heat convection box.

In contrast to the other embodiment variants, the lower cover is not present or at least has openings, so that pivotable flaps can be pivoted in and out as shielding elements, which are in the closed position II according to the illustration 2C separate the exhaust pipe 51 and the combustion gas pipe 50 from each other in terms of heat transfer.

The flaps can be designed as bent metal sheets and can be folded out or folded in to open the lower cover of the thermal convection box in order to separate the exhaust pipe 51 and the combustion gas line 50 from one another or to close the thermal convection box in order to separate the exhaust pipe 51 and the combustion gas pipe 50 with regard to connect to heat transfer. The unfolding and folding can in turn be carried out with intermediate positions provided for this purpose.

In this respect, the thermal convection box according to the third embodiment is characterized in that it has at least one openable (open in open position I = not shielded from the environment) or closable (closed in closed position II = shielded from the environment), pivoting flap (in the exemplary embodiment, two flaps ) or the like, so that it is a temporary shielding device 70 with at least one shielding element inside the thermal convection box, with the body of the thermal convection box itself not changing analogously to the separating element according to the second embodiment variant.

In turn, it is provided that the pivotable flaps can be opened and closed as required, analogously to the other embodiment variants, as is to be made clear in the illustrated embodiment variant using the arrow P2C.

Fourth variant:

In a fourth embodiment according to 2D provided that the control unit 33 controls a motor drive as an actuator 71, which is associated with at least one pivotable separating element, in particular a separating plate according to arrow P2D. It is intended that the pivotable separating element can be pivoted by means of the actuator 71 as required, analogously to the other embodiment variants, as should be illustrated in the illustrated embodiment variant using the arrow P2D.

The heat convection box is in 2D displayed three-dimensionally.

The exhaust gas line 51 and the combustion gas line 50 are thus led in and out of the heat convection box, analogously to the other embodiment variants.

In contrast to the other embodiment variants, it is provided that the pivotable separating element is not pulled out of the heat convection box (compare the explanations for the second embodiment variant), but from its in 2D shown vertical position, in which the lines 50, 51 are thermally in the disconnected position, to the horizontal position in which the lines 50, 51 are thermally not in the non-disconnected position, by 90 ° in the horizontal position. Analogously to the other embodiment variants, the pivoting can be carried out according to the invention in at least one intermediate position, for example by only 45°, for example.

In this respect, the thermal convection box according to the fourth embodiment is characterized in that, analogously to the second embodiment, the use of the pivotable separating element does not result in an open position I or closed position II of the thermal convection box, but rather a disconnected position or a non-disconnected position of the lines 50, 51 within the thermal convection box by pivoting the separating element about its pivot axis, which preferably (not necessarily) runs in the axial direction of the vehicle.

It goes without saying that the solution shown in the fourth embodiment variant can also be combined with solutions in which the heat convection box can be brought into an open position I or closed position II.

Preferred process engineering procedure:

With regard to the operation of the thermal convection box 70 within the system, according to a 3 The process flow program shown provides that the shielding device 70 of the heat convection box is initially arranged in the open position I, which is not shielded from the environment, as illustrated in the first rectangular block using the reference symbols.

Analogously, for the separating elements arranged above in the possible embodiment variants, this means that the at least one separating element is arranged in such a way that the heat transfer is separated from one another by the spatial separation of the exhaust gas line 51 from the combustion gas line 50 by assuming the separating position of the at least one separating element, so that the Heat transfer between exhaust gas line 51 and combustion gas line 50 is interrupted.

In an associated application for controlling control unit 33, pressure PT in combustion gas line 50 is measured using pressure sensor 80, with provision being made for a limit pressure PT _limit to be below limit pressure PT _limit , which can be specified as a threshold value and which is regarded as a signal at which the heat convection box remains in its open position I and is not closed.

In other words, only a pressure that is greater than the limit pressure PT _limit results in the application moving to the next method step, in which the temperature T2 of the environment is evaluated. The maximum pressure in the storage tank is 230 bar, for example. The predefinable limit pressure PT _limit is 150 bar, for example. According to the preferred procedure explained here, the application only moves to the next step above the specified limit pressure PT _limit .

As already explained, the temperature T2 of the environment is determined by the temperature sensor 32 in order to determine whether the ambient temperature is also below a specific temperature limit value T2 _limit that can be specified as a threshold value.

If the temperature in the environment is above the temperature limit value T2 _limit , i.e. if the temperature does not fall below a certain limit value T2 _limit of, for example, -20 °C to -40 °C, the thermal convection box also remains in its open position I or a separation/shielding of the The exhaust pipe 51 from the combustion gas pipe 50 through the separating elements remains and the heat convection box is not shielded from the environment by assuming the closed position II.

In other words, only when the threshold value, ie the specified temperature limit value T2 _limit of -20 °C to -40 °C is undershot, ie the temperatures are falling towards colder, for example -21 °C or -41 °C, is both the Ambient temperature T2 so low (T2 < T _limit ) and the corresponding limit pressure PT _limit in the exhaust gas line 51 is/are so high that the thermal convection box 70 is/are closed and brought into its closed position II and/or the separating device 72 is/are brought into the non-separating position.

This means that the at least one shielding element is brought into the closed position II and/or the at least one separating element is brought into the non-separated position and actuated, so that the heat transfer (convection) between the exhaust gas line 51 and the combustion gas line 50 is prevented by the lack of spatial separation of the lines 50, 51 by the at least one separating element between one another and/or by the shielding of the heat convection box from the environment, which stores heat in the heat convection box in the closed position II, takes place in an advantageous manner.

If the pressure PT in the combustion gas line 50 is high, i.e. > PT _limit and the temperature T2 in the environment is low, i.e. < T _limit , the method step takes place according to the second rectangular block, which indicates the closed position II of the thermal convection box or the shielding that is no longer present of the lines 50, 51 is intended to clarify one another using the reference numbers.

Within the application, these limit values are continuously queried as criteria K at a specifiable time cycle, with the heat convection box remaining closed or the lines 50, 51 not being shielded from one another as long as the two conditions are present.

Only when at least one of the conditions is no longer present is provision made for bringing the heating box 70 back into its open position I and/or for shielding the lines 50, 51 from one another.

Provision is also made for further criteria to be included in the program to be controlled by control unit 33 .

It is provided that the thermal convection box is opened or the lines 50, 51 are shielded from one another again depending on an engine compartment temperature and/or a predetermined time and/or the exceeding of the specified limit values T2 _limit and PT _limit . In this way, it can be achieved in particular that excessive heating of the combustion gas line 51 is prevented.

For example, a prediction model can be implemented, which predicts and activates the time when the thermal convection box is opened and/or the time when the lines 50, 51 are shielded.

A further preferred embodiment of the invention consists in the fact that the exhaust pipe 51 is profiled and/or the attachment of ribs to the exhaust pipe 51 is provided, so that an improved heat transfer can be brought about.

Parallel to this or taken separately, profiling of the combustion gas line 50 and/or the attachment of ribs to the combustion gas line 50 is also provided, so that improved heat transfer is also possible there.

Reference List

10

storage tank

20

shut-off valve

21

pressure reducer

31

temperature sensor

T1

Temperature in 70

32

temperature sensor

T2

temperature in environment

T2 limit

temperature limit

33

control unit

40

injection system

41

internal combustion engine

50

combustion gas line

51

exhaust pipe

60

exhaust gas discharge device

70

shielding device

71

actuator

71n

several actuators (n = number)

72

separator

80

pressure sensor

pt

Print

PTlimit

pressure limit

I

Open position 70

II

closed position 70

K

criteria

P2A

Arrow

P2B`

Arrow

P2B"

Arrow

P2C

Arrow

P2D

Arrow

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited 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

• DE 102018113239 A1 [0006]
• DE 102018118755 A1 [0007, 0008]
• DE 102009036669 A1 [0009]

Claims (10)

System for the safe operation of a combustion gas supply of an internal combustion engine (14) operated with a combustion gas, the exhaust gas of which is discharged via an exhaust gas removal device, characterized in that a combustion gas line (50) and/or at least one component of the combustion gas supply integrated into the combustion gas line (50) and a Exhaust pipe (51) and/or at least one component integrated into the exhaust pipe (51) are positioned on their pipe routing sections at least over a specifiable section length with a specifiable distance from one another, so that the components of the exhaust pipe (51) and/or the at least one component in the exhaust line (51) integrated component emitted convection heat in a heat transfer area to the combustion gas line 50 and/or to the at least one component integrated in the combustion gas line (50) and thus to the combustion gas in the combustion gas line (50). is carried, wherein the amount of heat that can be transferred can be influenced by a shielding device (70) and/or separating device (72) arranged in the heat transfer area of the predetermined common route length of the common line routing route, the shielding device (70) having means for reducing the amount of heat that can be transferred by convection between the combustion gas supply and the exhaust gas discharge device in the heat transfer area, with which the shielding device (70) can be temporarily brought from an open position (I) to a closed position (II) and vice versa, and the separating device (72) has means to Influencing convection transferable amount of heat between the combustion gas supply and the exhaust gas discharge device in the heat transfer area, with which the heat transfer area through the separating device (72) temporarily bringba from a disconnected position to a non-separated position and vice versa r is system after claim 1 , characterized in that an exhaust manifold and/or the exhaust line (16) of the exhaust gas discharge device and the combustion gas line (50) of the combustion gas supply, which form the heat transfer area formed with the shielding device (70) and/or the separating device (72), are in the engine compartment of the internal combustion engine (14) are arranged. system after claim 1 , characterized in that the exhaust gas line (51) of the exhaust gas discharge device and the combustion gas line (50) of the combustion gas supply, which form the heat transfer area formed with the shielding device (70) and/or the separating device (72), are installed in a vehicle floor or under a vehicle floor of a vehicle with the system-equipped vehicle are arranged. system after claim 2 or 3 , characterized in that the shielding device (70) is designed as a heat convection box which spatially encloses the heat transfer area between the combustion gas supply and the exhaust gas discharge device, with at least part of the heat convection box being designed to be movable as a shielding element which can be temporarily moved from the open position (I) to the environment can be brought into the closed position (II) and vice versa. system after claim 2 or 3 , characterized in that the separating device (72) is designed as a separating element which spatially separates the heat transfer area between the combustion gas supply and the exhaust gas discharge device, the separating element being temporarily movable from a separating position into a non-separating position and vice versa. system after the claims 4 and 5 , characterized in that the separating device (72) is integrated into the shielding device (70) designed as a heat convection box. system after claim 4 and/or 5, characterized in that the at least one shielding element of the shielding device (70) and the at least one separating element of the separating device (72) are provided with controllable actuators which switch the open position (I) and closed position (II) or at least one intermediate position of the Shielding device (70) or the disconnected position and non-connected position or at least one intermediate position of the disconnecting device (72) causes/effect. system after claim 1 , characterized in that a pressure sensor (80) is arranged in the combustion gas feed line of the system, which determines the pressure (PT) in the combustion gas feed line, and a temperature sensor (31) is arranged in the heat transfer area of the system, which determines the temperature (T1) in the heat transfer area and in a further temperature sensor (32) is arranged in the vicinity of the heat transfer area, which determines a temperature (T2) in the surroundings. Method for safe operation of a combustion gas supply of an internal combustion engine operated with a combustion gas (14) whose exhaust gas is discharged via an exhaust gas discharge device, characterized in that the shielding device (70) temporarily moves from an open position (I) to a closed position (II) and vice versa and/or the separating device (72) temporarily moves from a disconnected position to a non- Is / are brought disconnected position and vice versa, the closed position (II) and / or the non-disconnected position depending on a measured in the combustion gas supply pressure (PT), which is greater than a predeterminable limit pressure (PT _limit ) and / or depending a temperature (T2) measured in the environment that is lower than a predefinable limit temperature (T _limit ) is/are assumed. procedure after claim 9 , characterized in that the closed position (II) of the shielding device (70) and/or the non-separating position of the separating device (72) is only assumed when the pressure (PT) measured in the combustion gas supply is greater than the specified limit pressure (PT _Limit ) and the temperature measured in the environment (T2) is lower than the specified limit temperature (T _Limit ).

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