Internal combustion engine with a cylinder head with a pre-chamber and motor vehicle with such an internal combustion engine

Abstract

The present invention relates to a method for heating a pre-chamber (1) in a cylinder head (2) of an internal combustion engine (3). The essential feature of the invention is that the pre-chamber (1) is heated by means of an induction heating device (4) arranged in the cylinder head (2) of the internal combustion engine (3). This allows for a space-optimized and effective arrangement of the induction heating device (4) in the cylinder head (2).

Description

[0001] The present invention relates to an internal combustion engine with a cylinder head having a pre-chamber, according to the preamble of claim 1, and to a motor vehicle with such an internal combustion engine.

[0002] Pre-chamber ignition makes gasoline engines more efficient. This involves incorporating pre-chambers in the cylinder head, which closely enclose the ignition unit and are separated from the main combustion chamber, for example, by a perforated wall. After ignition of the fuel-air mixture in the pre-chamber, the pressure rises rapidly due to its relatively small volume, causing combustion jets to pass through the holes in the pre-chamber cap into the main combustion chamber. Ideally, this results in several, but at least one, ignition points in the main combustion chamber outside its center, generally leading to faster combustion and a reduced tendency to knock.

[0003] In order to reach operating temperature more quickly, especially during a cold start, and thus also to achieve improved emission behavior more quickly, it is known from the prior art to heat the pre-chamber or a charge air stream blown into it.

[0004] From DE 10 2007 019 882 A1 a method for heating a pre-chamber in a cylinder head of an internal combustion engine is known, in which the pre-chamber is heated by means of an induction heating device arranged in the cylinder head of the internal combustion engine.

[0005] From CN 1 18 030 268 A a gas supply system and a control method for a pre-combustion chamber of an internal combustion engine are known.

[0006] From DE 10 2019 114 204 A1, a method for injecting hot air into the pre-chamber of an internal combustion engine is known, in particular via an air-fuel injector, wherein the hot air is heated by a heating element and conveyed by a compressor. The compressor can be part of an exhaust gas turbocharger or compressor, which is additionally electrically driven, so that hot air can be injected into the pre-chamber even when the engine is stationary, in particular immediately before a cold start. The heating element can have an electrical conductor and, for example, heat a section of a hot air supply line.

[0007] From JP H01 - 116 216 A, an internal combustion engine with a swirl chamber made of a ceramic material, in which a heating coil is embedded, is known.

[0008] A disadvantage of the solutions known from the prior art for heating a pre-chamber in a cylinder head of an internal combustion engine is that the heating devices used for this purpose often exhibit increased wear and are installed in an unfavorable manner, particularly with regard to installation space.

[0009] The present invention therefore deals with the problem of providing an improved or at least alternative embodiment for an internal combustion engine of the generic type, by means of which in particular the disadvantages known from the prior art can be overcome.

[0010] This problem is solved according to the invention by the subject matter of independent claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0011] The present invention is based on the general concept of directly heating a pre-chamber of an internal combustion engine by means of an induction heating device and simultaneously accommodating this device in a cylinder head of the internal combustion engine in which the pre-chamber is also located. This allows the induction heating device according to the invention to heat the pre-chamber effectively and, compared to heating elements, with minimal wear, while also being arranged in a space-optimized manner within the cylinder head of the internal combustion engine, thus requiring no additional installation space.

[0012] In another embodiment of the method, the pre-chamber is heated by the induction heating device before and / or during a cold start of the internal combustion engine. Pre-heating the pre-chamber before a cold start offers the significant advantage that improved combustion, particularly with regard to pollutant emissions, can be achieved within the pre-chamber shortly after the engine starts. Since the pre-heating of the engine's pre-chamber before a cold start is purely electrical, the combustion of fossil fuels, as is the case with a conventional auxiliary heater, is unnecessary. By heating the pre-chamber before and / or during the cold start, the engine reaches its operating temperature more quickly, which also reduces pollutant emissions.

[0013] In a further embodiment of the method, the pre-chamber is heated by means of the induction heating device during operation of the internal combustion engine. Situations may also arise during operation of the internal combustion engine in which additional heating of the pre-chamber is beneficial, particularly with regard to reducing pollutant emissions, so that the pollutant emissions can be reduced by the method according to the invention even during operation of the internal combustion engine.

[0014] The present invention is further based on the general concept of an internal combustion engine comprising a cylinder head and a pre-chamber arranged therein, wherein, according to the invention, an induction heating device is provided in the cylinder head for heating the pre-chamber. This enables direct and thus highly efficient heating of the pre-chamber, as well as a space-saving arrangement of the induction heating device. Furthermore, by integrating the induction heating device into the cylinder head, it can be protected, thereby extending its service life and achieving low-wear operation.

[0015] In an advantageous embodiment of the internal combustion engine according to the invention, the pre-chamber can be at least partially cylindrical or convex. Regardless of the shape, but particularly preferably in the case of a cylindrical, cone-shaped, or convex pre-chamber, the induction heating device can have a coil arranged in the pre-chamber wall, thereby spirally surrounding the pre-chamber. This allows for direct heating of a wall of the pre-chamber and thus particularly effective heating of the pre-chamber.

[0016] The pre-chamber of the internal combustion engine according to the invention has a wall, in particular a convex one, and an external thread, via which it is screwed into an internal thread arranged in the cylinder head. This allows for a significantly simplified replacement of the pre-chamber in the event of repair and maintenance.

[0017] According to the invention, the induction heating device has a coil arranged radially outside the internal thread in the cylinder head. The coil of the induction heating device can thus be positioned very close to the pre-chamber and heat it effectively.

[0018] The present invention is further based on the general concept of providing a motor vehicle with an internal combustion engine as described in the preceding paragraph, thereby transferring the advantages described for the internal combustion engine to the motor vehicle. Specifically, these advantages lie in a faster achievement of operating temperature during a cold start and a reduced-emission start-up phase of the internal combustion engine, since preheating the pre-chamber allows for improved combustion and thus reduced pollutant emissions.

[0019] Further important features and advantages of the invention will become apparent from the dependent claims, the drawing and the associated description of the figures based on the drawing.

[0020] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the present invention. The components of a higher-level unit, such as a device, apparatus, or arrangement, mentioned above and those to be mentioned below, which are designated separately, can form separate parts or components of this unit or be integral areas or sections of this unit, even if this is depicted differently in the drawings.

[0021] A preferred embodiment of the invention is shown in the drawing and is explained in more detail in the following description.

[0022] The only Fig. Figure 1 shows a cross-sectional view through an internal combustion engine of a motor vehicle according to the invention.

[0023] According to the Fig. Figure 1 of an internal combustion engine 3 of a motor vehicle 8 according to the invention comprises a combustion chamber 10 and a pre-chamber 1. An ignition device 11 is arranged in the pre-chamber 1, by means of which a fuel-air mixture arranged in the pre-chamber 1 can be ignited prior to actual ignition in the combustion chamber 10. The ignition device 11 can comprise an ignition electrode, for example a center electrode, and a ground pin. In general, a unit consisting of the ignition device 11 and the pre-chamber 1 can be referred to as a pre-chamber ignition device.

[0024] The prechamber 1 is connected to the combustion chamber 10 via corresponding through-openings 12. The combustion chamber 10 forms the upper end of a cylinder 13, in which a piston 14 is mounted so as to be translationally adjustable. The provision of such a prechamber 1 offers the significant advantage of achieving multiple ignitions of the fuel-air mixture injected into the combustion chamber 10, thereby resulting in rapid combustion and a reduced tendency to knock. The multiple ignitions of the fuel-air mixture in the combustion chamber 10 occur due to the combustion jets / flare jets passing through the through-openings 12. The rapid combustion of the fuel-air mixture in the combustion chamber 10 primarily improves the knock limit, allowing an internal combustion engine 3 with such a prechamber 1, or with prechamber ignition, to operate more efficiently.This can subsequently have an impact on pollutant emissions.

[0025] In addition to the improved combustion of the fuel-air mixture in the combustion chamber 10 caused by the pre-chamber 1, HC emissions, and ideally also CO emissions, can preferably be reduced by heating the pre-chamber 1 before or during a cold start. Heating the pre-chamber 1 can also be advantageous with regard to combustion stability. According to the invention, this is achieved in the internal combustion engine 3 by means of an induction heating device 4. This induction heating device 4 has, for example, a coil 9 that is wound helically around the pre-chamber 1. It is, of course, understood that the material of the pre-chamber 1 enables inductive heating.

[0026] Looking again at the antechamber 1, it can be seen that it has a cylindrical area with a convex wall 5, which transitions into a hemispherical shape at the bottom. Compared to the hemispherical shape, the antechamber 1 has a Fig. 1. The top surface has a base into which the ignition device 11 is screwed. The ignition device 11 may also have a center electrode and a ground pin.

[0027] If one considers the Fig. A closer look at Figure 1 reveals that the pre-chamber 1, or rather its wall 5, has an external thread 6 through which it can be screwed into an internal thread 7 located in the cylinder head 2. Screwing the pre-chamber 1 to the cylinder head 2 offers the significant advantage that, in the event of maintenance or repair, the pre-chamber 1 and the ignition device 11 can be replaced relatively easily, simply by unscrewing them. The pre-chamber 1, together with the ignition device 11, can thus be used as a single unit.

[0028] The induction heating device 4 has, according to the Fig.1. A coil 9 is arranged radially outside the internal thread 7 in the cylinder head 2, so that the induction heating device 4 is located directly adjacent to the pre-chamber 1 or the pre-chamber ignition device and can heat it very effectively. Furthermore, by arranging the induction heating device 4 radially outside the internal thread 7 in the cylinder head 2, it is possible to position the induction heating device 4 not only in a space-optimized manner but also in a protected manner, thereby extending its service life.

[0029] In addition to preheating the pre-chamber 1 before and / or during a cold start of the internal combustion engine 3, it is also theoretically conceivable to heat the pre-chamber 1 during the operation of the internal combustion engine 3 under certain load conditions.

[0030] In summary, the induction heating device 4 arranged in the cylinder head 2 according to the invention, which is connected to the vehicle's electrical system 8 via an electrical connection 15, enables preferably low-emission operation of the internal combustion engine 3. Ideally, the induction heating device 4 can also positively influence combustion. Since the electrical connection 15 of the induction heating device 4 is preferably also located in the cylinder head 2, it can be arranged in a space-optimized and protected manner, thereby significantly reducing its susceptibility to faults.

Claims

[1] Internal combustion engine (3) with a cylinder head (2) with a pre-chamber (1) and with an induction heating device (4) arranged in the cylinder head (2) for heating the pre-chamber (1), characterized by , - that the antechamber (1) has a wall (5), in particular a convex one, - that the wall (5) has an external thread (6) through which it can be screwed into an internal thread (7) arranged in the cylinder head (2), - that the induction heating device (4) has a coil (9) arranged radially outside the internal thread (7) in the cylinder head (2). [2] Internal combustion engine (3) according to claim 1, characterized by , that the prechamber (1) is cylindrical in shape. [3] Motor vehicle (8) with an internal combustion engine (3) according to claim 1 or 2.

Images