AT524430B1 - Internal combustion engine with spark ignition - Google Patents

Abstract

The invention relates to an internal combustion engine (1) with spark ignition, comprising a cylinder head (2), at least one cylinder (3) with a combustion chamber (4), with a prechamber opening into the combustion chamber (4) in the cylinder head (2) for each cylinder (3). (5) is arranged with at least one ignition device (6), wherein a duct (7) with a control device (8) arranged therein is provided for introducing at least air into the antechamber (5), wherein an intake tract (9) is provided, the channel (7) branches off from the intake tract (9), the control device (8) being designed as a check valve and the channel (7) comprising at least one first injection device (17).

Description

description

INTERNAL COMBUSTION ENGINE WITH SPRINKLER IGNITION

The invention relates to an internal combustion engine with spark ignition, comprising a cylinder head, at least one cylinder with a combustion chamber, with a prechamber opening into the combustion chamber with at least one ignition device being arranged in the cylinder head for each cylinder, with a channel with a control device arranged therein for introduction of at least air is provided in the antechamber, wherein an intake tract is provided, wherein the channel branches off from the intake tract.

Internal combustion engines with an antechamber are known from the prior art.

[0003]Combustion processes with a prechamber are used, inter alia, in lean-burn, spark-ignited internal combustion engines. The advantage of initiating combustion in the pre-chamber instead of in the main combustion chamber is that even with high air/fuel ratios, low ignition energy is sufficient to ensure efficient and yet low-emission combustion of the entire cylinder charge. The antechamber is flow-connected to the main combustion chamber via one or more transfer channels formed by bores. The fuel/air mixture flows through one or more intake valves into the main combustion chamber and is then pushed into the pre-chamber during the compression process, so that a combustible mixture is available there.

[0004] Electrical spark ignition systems and pilot jet methods are used to ignite the fuel/air mixture. In the case of electrical spark ignition, additional fuel or a fuel/air mixture is often introduced into the prechamber in order to have a significantly richer and therefore more ignitable mixture available at the point of combustion initiation compared to the main combustion chamber. For this purpose, an injector is always arranged in the antechamber.

Other internal combustion engines with an antechamber and a channel are known, for example, from DE 2414022 A1, US 4369747, DE 2541214 A1, DE 102008045915 A1, US 2884913 A and DE 102015206074 A1.

A disadvantage of known solutions is that this requires a lot of space and the production costs are correspondingly high.

This is where the invention comes in. The object of the invention is to improve the ability to ignite in the antechamber and, in particular, to save installation space at the same time.

This object is achieved in that in the internal combustion engine of the type mentioned, the control device is designed as a check valve and the channel comprises at least one first injection device.

An advantage achieved in this way can be seen in particular in the fact that residual gas can be removed from the antechamber by the design of the internal combustion engine according to the invention, whereby an ignitable mixture is provided therein and an ignitability of the same can be improved. Because air is fed into the antechamber via the duct, it is flushed and cleaned of the residual gas present in it. The opening and closing of the duct can be regulated and/or controlled by the control device in order to control and/or completely prevent a flow rate of air conducted into the antechamber. According to the invention, the duct is designed in particular as an air duct. The channel provides a media-carrying connection between the inlet channel and the antechamber, at least air being able to be introduced through the channel into the antechamber, and it can advantageously also be provided that a fuel-air mixture can be introduced through the channel into the antechamber is. A flushed antechamber is consequently formed.

The channel is designed and arranged in particular for introducing air and at least one second medium into the antechamber. Below that the channel for insertion

If at least air is provided in the antechamber, it is to be understood within the scope of the invention that, in addition to air, at least one further medium (gaseous and/or liquid) can be introduced into the antechamber via the channel.

According to the invention, the internal combustion engine comprises an intake tract, via which air is conducted in the direction of the combustion chamber. The duct branches off from the intake tract and thus connects it to the antechamber. As a result, the intake stroke, which is present anyway and via which air is guided into the combustion chamber, can be used to provide air in the antechamber. The intake tract includes all elements into and through which air is directed and guided in the direction of the combustion chamber. In the production of a cylinder head of the internal combustion engine according to the invention, the channel is cast at the same time as the other components. However, it can also be provided that the cylinder head is machined after a casting process in such a way that the channel is formed.

The spark-ignited internal combustion engine according to the invention is designed in particular as a naturally aspirated engine or as a supercharged engine.

The internal combustion engine according to the invention can have one, two, three, four or more cylinders, with each cylinder having its own antechamber, i. H. the same number of antechambers as cylinders are provided. The air line splits into a separate air line for each cylinder at the latest before it enters the antechamber. However, it is favorable if only a single air line branches off from the intake tract, which only divides into several air lines downstream in the direction of the antechamber.

It can be provided that the antechamber is formed by an antechamber shell, wherein advantageously a sleeve can be provided which comprises the ignition device. The antechamber sleeve and the sleeve are in particular each formed in one piece and/or connected to one another. This allows the pre-chamber component to be easily removed from the cylinder head in the event of ignition problems, making repairs and replacements easier and less expensive. If the antechamber casing and the sleeve are connected to one another, this can be realized, for example, by a screw connection with a seal. Provision can therefore be made for the sleeve to be formed in one piece and the antechamber sleeve to be formed in one piece and then connected to one another. However, it can also be the case that the sleeve and the antechamber sleeve are formed together in one piece.

The flushed antechamber formed as a result, into which air can be introduced, results in a better ignitability of the mixture, particularly in areas in which an antechamber usually does not function as well as, for example, in catalytic converter heating, when operating the internal combustion engine at part load and/or during starting operation of the internal combustion engine.

It when the antechamber is free of an injection device is particularly advantageous. There is therefore no injection device, such as an injector in particular, provided in the antechamber itself. As a result, costs and space can be saved, as a result of which cooling, in particular of the cylinder head, is improved as a result of the small space requirement. In principle, however, it is also possible for an injection device to be provided in the antechamber, as a result of which it is designed as an active antechamber.

According to the invention it is provided that the channel comprises at least one first injection device. This is either arranged directly in the channel or opens into the channel. The first injection device is designed in particular as an injector and for injecting fuel into the channel and is provided upstream of the control device. As a result, the antechamber can be flushed not only with air but also with a fuel-air mixture. In particular, however, the first injection device is not arranged in the antechamber itself.

The flushed antechamber formed as a result, which can be flushed with air or with a fuel-air mixture, makes it possible to supply the antechamber with a rich or at least a highly ignitable mixture.

According to the invention it is further provided that the control device as a non-return

valve is formed. The control device can advantageously also be designed as a controlled quantity control valve. A flow direction and/or flow rate of air through the channel can be regulated by the valve. A transfer from the antechamber back into the channel is particularly preferably prevented by the control device. The control device can preferably extend over the entire length of the channel or can only be arranged in a part of the same.

In a preferred variant, a distribution device, which is designed in particular as a distribution pipe, can be provided for this purpose, for example in the cylinder head or in a valve cover upstream of the antechamber and upstream of the control device. The first injection device opens into the distributor device, with the distributor device having, in particular for each cylinder, an exit into that part of the channel which leads to the respective antechamber. In this variant, a common first injection device is therefore provided for all cylinders and thus antechambers. However, it can also be advantageous if more than one, in particular two or more, first injection devices are provided, all of which open into the same distributor device. The distribution device is arranged in the duct in such a way that air is combined with fuel in the distribution device and fed into the antechamber as a fuel-air mixture.

In a further preferred variant, a first injection device can be provided for each cylinder. It is advantageous if one mixing chamber is provided for each cylinder in the cylinder head or in a valve cover, upstream of the antechamber and upstream of the control device, with each mixing chamber being associated with an antechamber. It is also advantageous if a first injection device opens into each mixing chamber. Air is combined with fuel in each mixing chamber and fed into the respective antechamber as a fuel-air mixture.

In both variants described, it is favorable if an outlet is arranged in the direction of the antechamber on an upper side of the distribution device or mixing chambers, so that it is ensured that only a gaseous fuel-air mixture gets into the antechamber. Any liquid fuel can then settle on the bottom of the distribution device or mixing chambers and thus does not get into the antechamber(s).

It is also advantageous in both variants if the distribution device or mixing chambers not only have an air inlet (since they are arranged in the duct), but also have an air outlet, which branches off from the duct upstream of the control device. As a result, an air circulation line is created, whereby a predetermined air flow is always ensured in the distribution device or in the mixing chambers, with the air circulation line consequently branching off from the duct and, in particular, leading back into it via the intake tract. It is advantageous if a pump, such as a diaphragm pump, is provided in the air circulation line. In the variant with the mixing chambers, it is favorable if the air circulation line connects all the mixing chambers with one another and leads back into the duct. The distributor device or the mixing chambers therefore advantageously have an air outlet which opens into a recirculation line in order to recycle air back into the intake tract.

It is expedient if a throttle valve is arranged in the intake tract, the channel branching off from the intake tract upstream or downstream of the throttle valve. The air that is routed to the pre-chamber is therefore taken from the intake tract either before or after the throttle valve and routed via the duct into the pre-chamber. A pressure difference between the combustion chamber and an intake section is used to allow air to flow in the direction of the prechamber. It may consequently be necessary for the duct to branch off from the intake tract downstream of a compressor arranged in the intake tract in the case of an internal combustion engine designed as a turbo engine. It can also be advantageous if the duct branches off from the intake tract in front of an intercooler in order to bring warm air to the antechamber. In any case, it is favorable if the air branches off from the intake tract into the duct downstream of an air filter, thereby avoiding the provision of a separate air filter.

It is expedient if the internal combustion engine comprises at least one inlet port

at least one second injection device per cylinder being arranged in the intake port, the second injection device being designed in particular as a multi-point injector. In particular, the intake port is part of the intake tract and opens into the combustion chamber. Air and, if an injection device is present, a fuel-air mixture can be conducted into the combustion chamber via the intake port. Advantageously, no injector is provided in the antechamber itself.

It is favorable if at least one third injection device is provided for direct injection into the combustion chamber, which is designed in particular as a DI injector. Both an MPI injector per cylinder and a DI injector are particularly preferably provided in order to ensure optimal ignition capability both during a cold start and during normal operation of the internal combustion engine. However, it can advantageously also be provided that no second injection device is provided in the intake port and only at least one third injection device is provided.

A preheating device is advantageously provided, which is designed in particular as an electric glow plug or as a heating coil. The preheating device is arranged in particular in the duct upstream of the control device and is preferably used during a cold start of the internal combustion engine in order to heat the air which is fed into the prechamber. In regular operation of the internal combustion engine, the preheating device is generally not used. The arrangement of the preheating device means that a sufficiently high temperature level can be achieved in the antechamber, so that stable combustion in the antechamber is possible.

If the internal combustion engine has a distribution device or mixing chambers, a heating coil is advantageously provided in or around this in order to heat air or a fuel-air mixture in such a way that it is in particular gaseous. It can be advantageous if the at least one first injection device includes an additional preheating device, so that the fuel can be heated essentially immediately during injection. It can also be advantageous if the additional preheating device is provided instead of the preheating device in the distributor device or the mixing chambers.

It is also favorable if at least one additional ignition device is provided in the combustion chamber. This means that in addition to the ignition device in the antechamber, an ignition device and thus at least two ignition devices are also provided in the combustion chamber. In particular, the additional ignition device opens into the combustion chamber and improves the cold start properties of the internal combustion engine.

In the internal combustion engine according to the invention, it is favorable if the antechamber and the channel are formed integrally with the cylinder head. This means that preferably no additional components are necessary, which reduces costs. The channel is preferably simply cast at the same time as the cylinder head is cast, in which case it can also be drilled into it afterwards or be designed as a hose line.

[0031] Further features, advantages and effects result from the exemplary embodiment presented below. In the figures to which reference is made, shows:

1 shows a section through part of an internal combustion engine according to the invention;

[0033] FIG. 2 shows a schematic representation of a section of a further internal combustion engine according to the invention;

[0034] FIG. 3 shows a schematic representation of a section of a further internal combustion engine according to the invention;

4 shows a schematic representation of an internal combustion engine.

1 shows a section through an internal combustion engine 1 according to the invention in a longitudinal section. 1 shows a single-cylinder internal combustion engine or a cylinder 3 with a cylinder head 2 arranged above it. 4 shows an internal combustion engine 1 with 4 cylinders as an example.

The internal combustion engine has a cylinder head 2 and a cylinder block 16 , the cylinders 4 being arranged in the cylinder block 16 . Other details are not shown or visible in FIG. 4 for reasons of simplification.

The internal combustion engine 1 according to the invention comprises a cylinder head 2 and a cylinder 3 , a combustion chamber 4 being arranged in the cylinder 3 . An antechamber 5 is also provided, which adjoins the combustion chamber 4 approximately perpendicularly and opens into it. The antechamber 5 includes an ignition device 6 for igniting a combustible mixture, in particular of fuel and air.

In the cylinder head 2, a channel 7 for introducing air and a water jacket 15 for cooling the cylinder head 2 is further provided.

The channel 7 is flow-connected to the antechamber 5 so that air can flow from the channel 7 into the antechamber 5 . To control the flow between the channel 7 and the antechamber, a control device 8 designed as a valve is provided in the channel 7 . The control device 8 is preferably designed as a non-return valve in order to prevent a backflow from the antechamber 5 in the direction of the channel 7 .

An intake port 11 is also provided, which is part of an intake tract 9, not shown in FIG. The intake port 11 opens into the combustion chamber 4, with a second injection device 12 designed as a multi-point injector being arranged in the intake port 11, through which fuel enters the intake port 11 and from there as an air-fuel mixture into the combustion chamber 4, with the combustion chamber another ignition device is arranged.

Furthermore, a third injection device 13, which is designed as a DI injector, is provided, through which fuel can be introduced directly into the combustion chamber 6.

The internal combustion engine according to FIG. 1 comprises an intake tract 9 in which a throttle valve 10 is arranged. 1 shows two different embodiments of the internal combustion engine according to the invention: In a first embodiment, the channel 7 branches off upstream of the throttle valve 10 (solid line) and leads into the antechamber 5. In a second embodiment, the channel 7 branches downstream of the throttle valve 10 ( dashed line) and leads into the antechamber 5. The internal combustion engine shown in FIG.

In order to bring the air in the channel 7 to a predetermined temperature, a preheating device 14 is provided, which is preferably designed as an electrically operated glow plug and is arranged upstream of the control device 8 .

shows a schematic representation of a section of another internal combustion engine 1 according to the invention with four cylinders 3. A distributor device 18 is provided, into which a first injection device 17 opens. Only a single distributor device 18 is provided for the entire internal combustion engine 1 . The distributor device 18 is arranged in the channel 7 , with the channel 7 dividing into one channel 7 per cylinder 3 downstream of the distributor device 18 . Fuel can be injected into the distributor device 18 by the first injection device 17 and can be mixed with air there, as a result of which a fuel-air mixture is guided in the direction of the antechambers 5 . An air outlet 20 is also provided, which leads into an air circulation line, not shown, via which air is circulated at least through the distributor device 18 , in particular via the intake tract 9 .

In addition, the preheating device 14 is designed as a heating coil and is wound around the distribution device 17 . If this heating coil is provided, the preheating device 14 upstream of the valve can optionally be dispensed with, it also being possible for several preheating devices 14 to be provided.

3 shows a schematic representation of a section of a further internal combustion engine 1 according to the invention with three mixing chambers 19, a mixing chamber 19 being provided for each cylinder 3, ie also for each antechamber 5. In each mixing chamber 19 opens a

first injector 17 to mix fuel with air. The mixing chambers 19 are again arranged in the air line 7 . Each mixing chamber 19 includes an air outlet 20 which leads into an air circulation line, not shown, via which air is circulated through the mixing chambers 19 .

Claims (12)

patent claims Internal combustion engine (1) with spark ignition, comprising a cylinder head (2), at least one cylinder (3) with a combustion chamber (4), wherein in the cylinder head (2) per cylinder (3) there is a prechamber (4) opening into the combustion chamber (4). 5) is arranged with at least one ignition device (6), wherein a duct (7) with a control device (8) arranged therein is provided for introducing at least air into the antechamber (5), wherein an intake tract (9) is provided, wherein the duct (7) branches off from the intake tract (9), characterized in that the control device (8) is designed as a check valve and the duct (7) comprises at least one first injection device (17). 2. Internal combustion engine (1) according to claim 1, characterized in that the antechamber (5) is free of an injection device. 3. Internal combustion engine (1) according to claim 1, characterized in that a distributor device (18) is provided in the channel (7), the at least one first injection device (17) opening into the distributor device (18). 4. Internal combustion engine (1) according to claim 2, characterized in that the distributor device (18) has an air outlet (20), the air outlet (20) opening into a recirculation line in order to recycle air into the intake tract (9). 5. Internal combustion engine (1) according to claim 1, characterized in that at least one mixing chamber (19) is provided in the channel (7), the at least one first injection device (17) opening into the at least one mixing chamber (19). 6. Internal combustion engine (1) according to claim 5, characterized in that the at least one mixing chamber (19) has an air outlet (20), the air outlet (20) opening into a recirculation line in order to recycle air into the intake tract (9). 7. Internal combustion engine (1) according to any one of claims 1 to 6, characterized in that in the intake tract (9) a throttle valve (10) is arranged, wherein the channel (7) upstream of the throttle valve (10) from the intake tract (9) branches off. 8. Internal combustion engine (1) according to any one of claims 1 to 7, characterized in that in the intake tract (9) a throttle valve (10) is arranged, wherein the channel (7) downstream of the throttle valve (10) from the intake tract (9) branches off. 9. Internal combustion engine (1) according to one of Claims 1 to 8, characterized in that the internal combustion engine (1) comprises at least one intake port (11), with at least one second injection device (12) per cylinder (3) being arranged in the intake port (11). is, wherein the second injection device (12) is designed in particular as a multi-point injector. 10. Brennraftmaschine (1) according to any one of claims 1 to 9, characterized in that at least a third injection device (13) for direct injection into the combustion chamber (4) is provided. 11. Internal combustion engine according to any one of claims 1 to 10, characterized in that a preheating device (14) is provided. 12. Internal combustion engine according to any one of claims 1 to 11, characterized in that in the combustion chamber (4) at least one additional ignition device is provided. 3 sheets of drawings