DE102012014112A1 - Internal combustion engine for a motor vehicle - Google Patents

Abstract

The invention relates to an internal combustion engine (10) for a motor vehicle which can be operated with at least one gaseous fuel and has at least two combustion chambers (14), with a gas supply device (16) having at least one storage device (28) for storing the gaseous fuel , the injector elements (18) associated with the combustion chambers (14) for at least indirectly introducing the gaseous fuel into the combustion chambers (14) and a distribution element that is common to the injector elements (18) and fluidically connected to the storage device (28) and to the injector elements (18). 22), by means of which the distribution element (22) supplied gaseous fuel to the respective Injektorelemente (18) can be distributed, wherein at least one valve element (46) is provided, which in a corresponding line member (24) for guiding the gaseous fuel from Distribution element (22) to at least one m of the injector elements (18) is arranged and by means of which the corresponding conduit member (24) is fluidically lockable.

Description

The invention relates to an internal combustion engine for a motor vehicle specified in the preamble of claim 1. Art.

Such an internal combustion engine for a motor vehicle is the US 5,745,210 to be known as known. The internal combustion engine can be operated with at least one gaseous fuel and has at least two combustion chambers. A gas supply device is provided which comprises at least one storage device for storing the gaseous fuel. The gas supply device also includes injector elements associated with the combustion chambers for the at least indirect introduction of the gaseous fuel into the combustion chambers. In addition, the gas supply device comprises a distribution element which is common to the injector elements and is fluidically connected to the storage device and to the injector elements, by means of which the gaseous fuel supplied to the distribution element can be distributed to the respective injector elements.

After switching off the internal combustion engine, the gas supply device is initially under pressure. Leaks at the injector elements lead after stopping the internal combustion engine to emptying of the gas supply device, in particular of the distribution element, the injector elements and corresponding line elements for guiding the gaseous fuel into the combustion chambers. This can lead to undesirably high emissions of unburned hydrocarbons (HC) of the gaseous fuel. In addition, it may come to startup problems of the internal combustion engine due to the leaks.

Discharging the gaseous fuel to the environment is for environmental and safety reasons not advantageous because it would come to the emission of unburned hydrocarbons. A return of the gaseous fuel into the storage device and a discharge of the gaseous fuel in a separate container to reduce the gas pressure in the gas supply device after switching off the internal combustion engine, is technically complex and requires additional, large space.

It is therefore an object of the present invention, an internal combustion engine for a motor vehicle of the type mentioned in such a way that the above-mentioned problems after stopping the internal combustion engine can be avoided in a simple and space-saving manner or at least kept low.

This object is achieved by an internal combustion engine for a motor vehicle, in particular a passenger car, having the features of patent claim 1. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the remaining claims.

In order to provide an internal combustion engine for a motor vehicle specified in the preamble of claim 1 species, in which the described and resulting from the leaks of the injector disadvantages can be avoided in a simple and space-saving way or kept very low, at least one valve element is provided according to the invention is arranged in a corresponding line element for guiding the gaseous fuel from the distribution element to at least one of the injector elements and by means of which the corresponding line element can be fluidly blocked. In other words, the valve element is arranged in the direction of flow of the gaseous fuel from the distribution element to the at least one injector element downstream of the distribution element and upstream of the at least one injector element at least partially in the conduit element.

As a result, a gas volume, which can be emptied in the event of a leakage of the injector elements into the combustion chamber or the combustion chambers, can be kept particularly low. As a result, the emission of unburned hydrocarbons, especially methane, can also be avoided or kept to a minimum. In addition, a particularly advantageous starting behavior of the internal combustion engine is possible in terms of time after it has been switched off or after it has been deactivated. Furthermore, deflagrations in an intake tract and / or in an exhaust tract of the internal combustion engine can be avoided.

By appropriate arrangement of the at least one valve element in the corresponding line element particularly close to the corresponding injector, the gas volume, which can flow into the combustion chamber after stopping the internal combustion engine, at least substantially to a corresponding receiving volume of the injector, in which the injector gaseous fuel can record. This very low gas volume can be considered as uncritical with regard to the emission of unburned hydrocarbons, the influence of the starting behavior as well as the influence of deflagrations in the intake and / or exhaust tract.

In a further embodiment of the invention, the injector elements are each fluidically connected via at least one line element for guiding the gaseous fuel from the distribution element to the respective injector element with the distribution element. In order to keep the gas volume emptying into the combustion chambers after switching off the internal combustion engine particularly low, at least one respective, corresponding valve element is advantageously provided in the respective line element, ie downstream of the distribution element and upstream of the respective injector elements, by means of which the respective corresponding line element can be fluidly blocked is. In other words, in each of the line elements, via which the injector elements are connected to the distribution element, a corresponding valve element for fluidically blocking the corresponding line element is provided.

In a further embodiment of the invention, the valve element is designed as an electromagnetically operable valve element. As a result, fast switching times of the valve element can be realized, so that the corresponding line element can be blocked fluidically particularly fast during or after switching off the internal combustion engine.

To realize a very good sealing effect of the corresponding valve element is provided in a further advantageous embodiment of the invention that the valve element comprises at least one elastomer for fluidic blocking of the conduit member.

In a further embodiment of the invention, a control device is provided, which is designed to fluidly block the line element as a function of stopping the introduction of the gaseous fuel into the combustion chambers. In other words, a method for operating the internal combustion engine is provided, wherein the line element is fluidly blocked in response to the termination of the introduction of the gaseous fuel into the combustion chambers. As a result, it is possible to react to the switching off or deactivation of the internal combustion engine in order to keep the amount or the volume of gaseous fuel flowing into the combustion chambers particularly low after deactivating the internal combustion engine.

It is preferably provided that the control device is designed to fluidly block the line element in an automatic and / or in a caused by a person by deactivating the internal combustion engine finishing the introduction of the fuel into the combustion chambers. The automatic termination of the introduction of the fuel into the combustion chambers is carried out, for example, in the context of a so-called start / stop method, in which the internal combustion engine automatically fulfills at least one predeterminable criterion, ie. H. without intervention of the driver of the motor vehicle, is deactivated. Such an automatic deactivation occurs, for example, when the driver stops the motor vehicle at a red traffic light and the motor vehicle no longer has to be driven or driven by the internal combustion engine.

For automatically terminating the introduction of the fuel into the combustion chambers, it may also come during an overrun operation of the internal combustion engine, in which the internal combustion engine is not driven by running in the combustion chambers combustion processes, but via the internal combustion engine in a train drive drivable wheels of the motor vehicle by its kinetic energy , In both cases, d. H. both during the start / stop process and during the overrun operation, in order to save fuel, no fuel is introduced into the combustion chambers and no burns are performed in the combustion chambers. In order to avoid or minimize the gas volume which is emptying into the combustion chambers and the resulting disadvantages, in particular when the internal combustion engine is restarted, the corresponding line element is fluidly blocked by means of the corresponding valve element.

In a further embodiment of the invention, the internal combustion engine is operable in a first operating state with the gaseous fuel and in a second operating state with a liquid fuel. It is thus a bivalent combustion engine. For this purpose, for example, a fuel supply device is provided which comprises at least one tank for storing the liquid fuel and corresponding fuel injection valves for at least indirectly introducing the liquid fuel into the combustion chambers.

In order to keep the emptying gas volume particularly low, it is provided that the line element of the gas supply device is fluidly blocked in the second operating state by means of the valve element.

In a further advantageous embodiment of the invention, the storage device is fluidically connected to the distribution element via at least one further line element, wherein at least one further flow direction of the gaseous fuel from the storage device to the distribution element in the further line element Valve element is provided, by means of which the further conduit element is fluidly blocked, although the first conduit member is fluidly blocked by means of the first valve element. In other words, the circuit of the first valve element with the at least one, further valve element, so that a particularly high density of the gas supply device is realized.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and combinations of features mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figure can be used not only in the respectively indicated combination but also in other combinations or alone, without the frame to leave the invention.

The drawing shows in the single FIGURE is a schematic representation of an internal combustion engine of a motor vehicle, which is operable with a gaseous fuel and a gas supply device for supplying the internal combustion engine with the gaseous fuel, wherein valve elements are provided, by means of which after deactivating the internal combustion engine in Combustion chambers of this emptying gas volume can be kept particularly low.

The figure shows an internal combustion engine 10 for a motor vehicle. The internal combustion engine 10 is operable with a gaseous fuel and includes a crankcase 12 , which as combustion chambers of the internal combustion engine 10 several cylinders 14 having. The internal combustion engine 10 also includes an intake tract 15 , about which air sucked in and the cylinders 14 is supplied.

The internal combustion engine 10 also has a gas supply device 16 for supplying the internal combustion engine 10 with the gaseous fuel on. The gas supply device 16 includes injectors 18 by means of which the gaseous fuel directly into the cylinder 14 einbringbar, ie is inflatable. In other words, each is the cylinder 14 a respective injector 18 associated with one of the injectors 18 respective volume flow of the gaseous fuel directly into the respective cylinder 14 ie without the intake tract 15 to flow through. Thus, the gaseous fuel is injected directly into the cylinders 14 and not about upstream in the intake 15 introduced, ie blown. In the intake tract 15 is a throttle 20 arranged, by means of which one of the cylinders 14 adjustable amount of air is adjustable. Depending on the cylinders 14 amount of air supplied is also the cylinders 14 to be supplied amount of the gaseous fuel.

The gas supply device 16 also includes a distribution element 22 , which is also commonly referred to as a gas distributor. The distribution element 22 is about each line elements 24 with the injectors 18 fluidly connected. This allows the injectors 18 over the pipe elements 24 gaseous fuel from the injectors 18 common distribution element 22 be supplied.

The distribution element 22 is about another line element 26 fluidly with a gas tank 28 the gas supply device 16 connected so that the distribution element 22 over the further line element 26 gaseous fuel from the gas tank 28 can be supplied. In the further line element 26 is a pressure regulator 30 arranged, which for example comprises a valve element. By means of the pressure regulator 30 may be a pressure of the gaseous fuel in the distribution element 22 can be adjusted, with which the gaseous fuel from the distribution element 22 over the pipe elements 24 to the respective injectors 18 is distributed. By means of the gas supply device 16 the gaseous fuel gets into the cylinders 14 blown, which is why the gas supply device 16 Also referred to as Einblaseeinrichtung.

The internal combustion engine 10 further includes an exhaust tract 32 , by means of which exhaust gas of the internal combustion engine 10 , which results from burns of a fuel-air mixture in the cylinders 14 results, is dissipated.

To the internal combustion engine 10 Being able to operate particularly efficiently is also an exhaust gas turbocharger 34 intended. The turbocharger 34 includes a compressor 36 with one in the intake tract 15 arranged compressor wheel 38 , By means of the compressor wheel 38 can that of the internal combustion engine 10 be compressed air to be supplied.

For driving the compressor wheel 38 includes the exhaust gas turbocharger 34 a turbine 40 with one in the exhaust tract 32 arranged turbine wheel 42 , The turbine wheel 42 is driven by the exhaust and a shaft 44 the exhaust gas turbocharger 34 with the compressor wheel 38 coupled. In the flow direction of the exhaust gas through the exhaust tract 32 is downstream of the turbine wheel 42 an exhaust aftertreatment device 45 arranged, which for example comprises a catalyst.

After switching off the internal combustion engine 10 ie after deactivating the internal combustion engine 10 , stands the gas supply device 16 initially under pressure. Leaks at the injectors 18 lead after switching off the internal combustion engine 10 for emptying the gas supply device 16 in the cylinders 14 and optionally in the intake tract 15 if no appropriate countermeasures are taken. In this case, the gaseous fuel flows upstream of the cylinder 14 , For example, from the line elements 24 . 26 and the injectors 18 into the cylinder 14 one. Particularly in the case of direct introduction or direct injection of the gaseous fuel, as in the internal combustion engine 10 is provided, it can lead to a relatively high gas leakage, since a seal in particular of the injectors 18 with elastomers due to high component temperatures is not possible. The elastomers would be thermally destroyed.

To now an influx of an undesirably high volume of gas into the cylinder 14 after switching off the internal combustion engine 10 to avoid is in the respective line element 24 a respective, corresponding valve element 46 arranged, by means of which the respective corresponding conduit element 24 is fluidic lockable. In other words, in the conduit elements 24 respective valve elements 46 for fluidic blocking of the line elements 24 provided, which in the flow direction of the gaseous fuel from the distribution element 22 to the respective injectors 18 between the distribution element 22 and the injectors 18 are arranged.

The valve elements 46 are magnetically actuated, which is why they are also referred to as solenoid valves. The valve elements 46 be by means of an electronic control unit 48 the internal combustion engine 10 between one of the conduit elements 24 fluidly obstructing blocking position and one of the line elements 24 at least partially adjusted fluidically releasing release position.

Will the internal combustion engine 10 deactivated, so are the valve elements 46 adjusted in their respective blocking positions. This is due to the leaks of the injectors 18 only for emptying a very small volume of gas, which is based on a respective receiving volume of the injectors 18 , in which gaseous fuel is absorbable limited. This small gas volume can with regard to the emission of unburned hydrocarbons (HC), in particular unburned methane, as well as with respect to an influence on a starting behavior of the internal combustion engine 10 as well as deflagrations in the intake tract 15 and in the exhaust tract 32 be regarded as uncritical.

Eventually, when deactivating the internal combustion engine 10 in the distribution element 22 absorbed, gaseous fuel as well as further upstream in the line element 26 and in the gas tank 28 Ingested fuel can not through the leaks of the injectors 18 in the cylinders 14 inflow, since such a flow path by means of the valve elements located in the blocking position 46 is fluidly locked.

In the subsequent starting the internal combustion engine 10 become the additional valve elements 46 by means of the control unit 48 switched back to their respective release positions and thereby opened, so that the gaseous fuel again from the gas tank 28 to the injectors 18 and into the cylinders 14 can flow.

To a particularly high sealing effect of the valve elements 46 To realize these, in each case at least one elastomer for fluidic blocking of the respective line element 24 include. The use of such an elastomer is possible because the valve elements 46 a much lower temperature stress than the injectors 18 , So that the respective elastomer is not thermally or only very little claimed. Thus, an undesirable, thermal destruction of the elastomers can be avoided, so that they over a very long life away the line elements 24 can close tightly.

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• US 5745210 [0002]

Claims (9)

Internal combustion engine ( 10 ) for a motor vehicle which is operable with at least one gaseous fuel and at least two combustion chambers ( 14 ), with a gas supply device ( 16 ), which at least one memory device ( 28 ) for storing the gaseous fuel, the respective combustion chambers ( 14 ) associated injector elements ( 18 ) for the at least indirect introduction of the gaseous fuel into the combustion chambers ( 14 ) and one of the injector elements ( 18 ) common, with the memory device ( 28 ) and with the injector elements ( 18 ) fluidically connected distribution element ( 22 ) by means of which the distribution element ( 22 ) supplied gaseous fuel to the respective injector elements ( 18 ) is distributable, characterized in that at least one valve element ( 46 ) is provided, which in a corresponding line element ( 24 ) for guiding the gaseous fuel from the distribution element ( 22 ) to at least one of the injector elements ( 18 ) is arranged and by means of which the corresponding line element ( 24 ) is fluidically lockable. Internal combustion engine ( 10 ) according to claim 1, characterized in that the injector elements ( 18 ) in each case via at least one line element ( 24 ) for guiding the gaseous fuel from the distribution element ( 22 ) to the respective injector element ( 18 ) with the distribution element ( 22 ) are fluidically connected, wherein in the respective line element ( 24 ) at least one respective, corresponding valve element ( 46 ) is provided, by means of which the respectively corresponding line element ( 24 ) is fluidically lockable. Internal combustion engine ( 10 ) according to one of claims 1 or 2, characterized in that the valve element ( 46 ) as an electromagnetically operable valve element ( 46 ) is trained. Internal combustion engine ( 10 ) according to one of the preceding claims, characterized in that the valve element ( 46 ) at least one elastomer for fluidic blocking of the line element ( 24 ). Internal combustion engine ( 10 ) according to one of the preceding claims, characterized in that a control device ( 48 ) is provided, which is adapted to the line element ( 24 ) in response to an end of the introduction of the gaseous fuel into the combustion chambers ( 14 ) by means of the valve element ( 46 ) fluidly to block. Internal combustion engine ( 10 ) according to claim 5, characterized in that the control device ( 48 ) is adapted to the line element ( 24 ) in an automatic and / or by a person by deactivating the internal combustion engine ( 12 ) brought to an end the introduction of the fuel into the combustion chambers ( 14 ) by means of the valve element ( 46 ) fluidly to block. Internal combustion engine ( 10 ) according to one of the preceding claims, characterized in that the internal combustion engine ( 12 ) is operable in a first operating state with the gaseous fuel and in a second operating state with a liquid fuel, wherein the line element ( 24 ) in the second operating state by means of the valve element ( 46 ) is fluidly blocked. Internal combustion engine ( 10 ) according to one of the preceding claims, characterized in that the memory device ( 28 ) via at least one further line element ( 26 ) with the distribution element ( 22 ) is fluidically connected, wherein in the flow direction of the gaseous fuel from the storage device ( 28 ) to the distribution element ( 22 ) in the further line element ( 26 ) at least one further valve element between the distribution element ( 22 ) and the memory device ( 28 ) is provided, by means of which the further line element ( 26 ) is fluidly blocked, although the first line element ( 24 ) by means of the first valve element ( 46 ) is fluidly blocked. Car with an internal combustion engine ( 10 ) according to any one of the preceding claims.

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