Exogenous ignition internal combustion engine

Abstract

The invention relates to an externally ignited internal combustion engine (1) comprising a cylinder head (2), at least one cylinder (3) with a combustion chamber (4), wherein in the cylinder head (2) for each cylinder a prechamber (5) is arranged which opens into the combustion chamber (4) and has at least one ignition device (6) and at least one intake duct (7), wherein a communication channel (8) is provided together with a control device (9) arranged in the communication channel (8), wherein the communication channel connects the intake duct (7) and the prechamber (5) in flow communication.

Description

Technical Field

[0001] The present invention relates to an externally ignited internal combustion engine, comprising a cylinder head and at least one cylinder having a combustion chamber, wherein, for each cylinder, a pre-combustion chamber with at least one ignition device and an intake passage are arranged in the cylinder head to lead into the combustion chamber. Background Technology

[0002] Internal combustion engines with pre-combustion chambers have been disclosed in the prior art.

[0003] Combustion methods utilizing a pre-combustion chamber are particularly applicable in lean-fuel, externally spark-ignition internal combustion engines. The advantage of starting combustion in the pre-combustion chamber, rather than the main combustion chamber, is that even with a high air-to-fuel ratio, the small ignition energy is sufficient to ensure efficient and low-toxicity combustion throughout the cylinder. The pre-combustion chamber is connected to the main combustion chamber via one or more overflow channels consisting of orifices. The fuel-air mixture flows into the main combustion chamber via one or more intake valves and is subsequently diverted into the pre-combustion chamber during compression, thus providing an ignitable mixture within the pre-combustion chamber.

[0004] For the ignition of the fuel-air mixture, electric spark ignition systems and fuel injection ignition methods are employed. In the case of electric spark ignition, additional fuel or fuel-air mixture is repeatedly introduced into the pre-combustion chamber to ensure that the combustion initiation point has a significantly richer mixture than that in the main combustion chamber, and therefore a higher ignition rate. For this purpose, injectors are always arranged in the pre-combustion chamber.

[0005] The known drawback of the solution is that it requires a lot of structural space and the manufacturing cost is correspondingly high in this case. Summary of the Invention

[0006] This invention addresses this issue. The objective of this invention is to improve the ignitability of the pre-combustion chamber while simultaneously saving structural space.

[0007] According to the present invention, this task is accomplished in an internal combustion engine of the type described in the preamble by providing a communication channel together with a control device disposed in the communication channel, wherein the communication channel connects the intake manifold and the pre-combustion chamber in a circulating manner.

[0008] The advantage gained is particularly that residual gases can be removed from the pre-combustion chamber by means of the internal combustion engine design according to the invention, thereby providing an ignitable mixture therein and improving its ignitability. A portion of the air supplied from the intake manifold to the combustion chamber is supplied to the pre-combustion chamber through a connecting passage, thereby purging it with air and removing residual gases therein. The opening and closing of the connecting passage is adjustable and / or controllable by a control device, so as to control and / or completely prohibit the flow from the intake manifold to the pre-combustion chamber. According to the invention, the connecting passage establishes a particularly guiding communication between the intake manifold and the pre-combustion chamber. This thus forms a purged pre-combustion chamber. The connecting passage is particularly designed and arranged to have a pressure differential therebetween.

[0009] The externally ignited internal combustion engine according to the present invention is particularly designed as an air-breathing engine or a turbocharged engine.

[0010] It can be specified here that the pre-combustion chamber is constructed by a pre-combustion chamber sleeve, wherein, advantageously, a sleeve comprising the ignition device can be provided. The pre-combustion chamber sleeve and the sleeve are particularly integrally constructed and / or interconnected. This allows for easy removal of the pre-combustion chamber components from the cylinder head in case of ignition problems, making maintenance and replacement easier and cheaper. When the pre-combustion chamber sleeve and the sleeve are interconnected, this can be achieved, for example, through a threaded connection with a seal. Therefore, it can be specified that the sleeve is designed as an integral piece, and the pre-combustion chamber sleeve is designed as an integral piece, and then they are interconnected. However, it is also possible that the sleeve and the pre-combustion chamber sleeve are jointly integrally constructed.

[0011] A particular advantage is that the pre-combustion chamber lacks an injection device. Therefore, no injection device, especially an injector, is installed within the pre-combustion chamber itself. This saves cost and space, and consequently improves cooling, especially for the cylinder head, due to the smaller footprint. In existing internal combustion engines with pre-combustion chambers, injectors are always installed within the chamber, and these injectors must be cooled or designed as passive pre-combustion chambers.

[0012] Advantageously, the control device is designed as a valve, particularly a check valve or throttle valve. Advantageously, the control device can also be designed as a controllable flow regulating valve. The valve controls the flow direction and / or flow rate between the intake manifold and the pre-combustion chamber. Particularly preferably, the control device prevents backflow from the pre-combustion chamber into the intake manifold. The control device preferably covers the entire length of the connecting passage or is arranged only in a portion thereof. An injector is preferably installed in the intake manifold, thereby enabling the control device to deliver a predetermined amount of fuel along with air into the pre-combustion chamber.

[0013] Advantageously, the control device is designed as a check valve with a valve body having two flow holes, wherein the medium can flow through the check valve from the first flow hole to the second flow hole. The check valve also includes a spring element and a closing device with a valve disc element, wherein the closing device is connected to the spring element at a first end, and the valve disc element is arranged at the second end of the closing device, wherein the valve disc element opens the second flow hole when the pressure exceeds a predetermined limit, wherein a connecting passage is provided with the control device disposed within the connecting passage, wherein the connecting passage connects the intake passage and the pre-combustion chamber.

[0014] The advantages of this are, in particular, that the baffle reduces the minimum pressure required for the medium to flow through the check valve. It also prevents backflow.

[0015] A check valve, in principle, allows the medium to flow in only one direction. The medium flows into the check valve through a first flow orifice, and flows out through a second flow orifice when the valve disc is in the open position. The valve disc is either part of or integral with the sealing device, or is fixedly connected to it. A diaphragm is also fixed to the sealing device, which has a thickened portion downstream of the diaphragm. The sealing device is longitudinally elongated upstream of the valve disc and has a constant diameter outside the thickened region. Within the thickened region, the sealing member has a larger diameter, so the diaphragm rests against the thickened portion. If the pressure applied to the diaphragm is sufficient, it will move, thereby transmitting the pressure of the diaphragm to the valve disc. That is, when the medium pressure applied to the diaphragm is high enough, the valve disc opens, in particular, along with the diaphragm. The medium pressure required for the diaphragm and thus the entire sealing device to move in the direction of medium flow is predetermined.

[0016] If no medium flows through the check valve or the medium pressure is too low to open the sealing device, the sealing device can be moved back to the closed position by means of a spring, especially one that is fixed in position on the sealing device.

[0017] The closure device opens from a specified pressure when the medium contacts its components (valve disc or diaphragm). The closure device can also open the flow orifice when a specified pressure differential is exceeded, where, within the scope of this invention, the pressure differential refers to a specified increase in the pressure of the medium applied to the closure device. This can also change from 0 to a specific value, for example, if there is initially no medium flow or surge, and then the medium enters the check valve through the first flow orifice.

[0018] The valve disc is particularly positioned downstream of the second flow orifice and is opened by medium pressure along the flow direction away from the second flow orifice.

[0019] The baffle is specifically designed as a plate, that is, it is essentially cylindrical, with its diameter being many times greater than its height. The valve disc is designed as a disc, with its diameter also being significantly greater than its maximum height. The height of the valve disc is not constant due to its geometry, with the maximum height occurring at the connection point with the remainder of the sealing device.

[0020] The valve body has internally designed orifices for the flow of media, with a narrowing formed particularly in the region of the second flow orifice, against which the valve disc rests when no pressure is applied. This narrowing is formed, in particular, by increasing the valve body material, and constitutes a valve seat for the diaphragm.

[0021] Check valves are designed for the flow of gaseous or liquid media or mixtures thereof. For example, the media can be a mixture of liquid fuel and air.

[0022] Advantageously, the diaphragm prevents the medium from flowing through the check valve in the closed position, and allows the medium to flow through when a specified differential pressure is exceeded, wherein the differential pressure required to open the diaphragm is less than the differential pressure required to open the valve disc. This ensures that the closure device opens even under very small pressure changes, thereby opening the check valve for flow in the desired and only direction.

[0023] Advantageously, the diameter of the diaphragm is larger than the diameter of the valve disc. This means that the diaphragm extends radially outward beyond the valve disc within the check valve. This ensures that the diaphragm continues to move in the flow direction even at low pressures.

[0024] It is also advantageous if the valve disc is at least substantially against the valve seat of the valve body in the closed position. This closes the entire check valve, preventing any medium from flowing through. The valve seat also ensures that the check valve is always closed in the other direction. Regarding the contact with the valve seat, it is particularly possible that the valve disc may not be fully or tightly against the valve seat. Therefore, the valve disc is preferably against the valve seat in such a way that it does not insert into but still closes the second flow hole. Alternatively, the valve disc can be submerged with a small gap. However, in principle, the valve disc can also be completely against the valve seat.

[0025] Advantageously, the diaphragm, in the closed position, rests at least substantially against another seat of the valve body. This other seat correspondingly possesses the same advantages as the seat of the valve disc assembly and cooperates with it to prevent the closure from moving against the flow direction. Regarding its resting against the other seat, it is worth noting that the diaphragm is not fully or tightly abutted, thus not providing a double fit. Therefore, the diaphragm is preferably generally abutted against the seat, so that it does not, in particular, insert into but still closes the second flow orifice. Alternatively, the diaphragm can also be submerged with a small gap.

[0026] Preferably, a chamber is formed between the valve disc and the partition. When the closure is in the open position, the medium flows through or through this chamber toward the second flow hole. The longitudinal portion of the closure device passes approximately centrally through the chamber.

[0027] Check valves are made, in particular, at least mostly, of wear-resistant steel. They are also preferably manufactured using 3D printing methods.

[0028] Particularly preferably, a check valve is provided having a valve body with two flow holes, wherein the check valve is capable of having a medium flow through it from the first flow hole along the direction of the second flow hole, and further includes a spring element and a sealing device having a valve disc element, wherein a first end of the sealing device is connected to the spring element, and the valve disc element is arranged at the second end of the sealing device, wherein the valve disc element opens the second flow hole when a specified pressure is exceeded, wherein a connecting channel is provided together with a control device disposed within the connecting channel, wherein the connecting channel connects the air intake passage and the pre-combustion chamber in a flow manner. This check valve is preferably designed as described above.

[0029] Check valves are preferably used in the cylinder head of internal combustion engines, especially in the connecting passage through which the fuel-air mixture flows.

[0030] Advantageously, the intake manifold has two separate intake passages connected by a channel partition wall between the separate intake passages, wherein the connecting passage leads into the pre-combustion chamber within the channel partition wall. Preferably, the connecting passage branches into the pre-combustion chamber upstream of the division point of the separate intake passages. The separate intake passages lead into the combustion chamber and introduce air into it. Preferably, the intake manifold is divided into two separate intake passages in the flow direction, which lead into the combustion chamber to introduce air and / or a fuel-air mixture into the combustion chamber. Internal combustion engines with this type of cylinder head can be easily manufactured. In particular, this cylinder head is manufactured by casting.

[0031] In principle, it may also be advantageous to divide the intake duct into two separate intake ducts, which then lead into the combustion chamber, with the connecting passage extending from one of the separate intake ducts to the pre-combustion chamber. Alternatively, it may be specified that a connecting passage extends from each of the two separate intake ducts, merging upstream of the pre-combustion chamber into a single connecting passage leading into the pre-combustion chamber. It may also be suitable to have a connecting passage from each of the two separate intake ducts to the pre-combustion chamber, thus positioning two connecting passages between the intake duct and the pre-combustion chamber.

[0032] If an internal combustion engine includes more than one cylinder and therefore more than one pre-combustion chamber, then each pre-combustion chamber is provided with its own connecting passage. It can branch off from its respective intake manifold, or it can first have a common connecting passage, which also branches off into separate connecting passages towards its respective pre-combustion chamber.

[0033] Suitablely, at least one first injection device is arranged in the intake manifold for each cylinder, wherein the first injection device is particularly designed as a multi-point injector. Therefore, no injector is located in the pre-combustion chamber itself, but rather a multi-point injector (MPI injector) is used for fuel injection, particularly one already located in the intake manifold. A higher mixture ignition capability is obtained through the resulting purged pre-combustion chamber, which can be supplied with fuel or a fuel-air mixture, especially in areas where the pre-combustion chamber typically does not function as well as, for example, during catalytic heating, partial load operation of the internal combustion engine, and / or engine start-up operation. Unlike passive pre-combustion chambers, in the internal combustion engine of the present invention, fuel is indirectly supplied to the pre-combustion chamber via a control device located in a communication channel. Air or a fuel-air mixture can be introduced into the pre-combustion chamber via the communication channel, depending on the operating point of the internal combustion engine. The pre-combustion chamber, thus designed, is therefore purged with air or a fuel-air mixture.

[0034] Particularly preferably, the first injection device is arranged such that its fuel flow is directed toward the opening of the connecting channel into the pre-combustion chamber. This further improves the ignition capability of the mixture, because there is always sufficient fuel and / or fuel-air mixture, which is also sufficiently rapid to reach the ignition device within the pre-combustion chamber. The flow direction of the fuel flow is thus aligned with the pre-combustion chamber, particularly with the opening of the connecting channel into the pre-combustion chamber, due to the injection device that generates the fuel flow. The fuel flow thus reaches the ignition device with minimal flow resistance.

[0035] In the internal combustion engine of the present invention, since the pre-combustion chamber itself does not have an injection device, the structural space is optimized and space is saved, and optimal ignition is ensured by simultaneously inputting a fuel-air mixture through a connecting channel.

[0036] Advantageously, a second injection device is provided for direct injection into the combustion chamber, which is specifically designed as a DI injector. It may be advantageous to provide only the second injection device for direct injection into the combustion chamber. That is, no injector is provided in the pre-combustion chamber, nor in the intake manifold. It is advantageous to provide one second injection device for each cylinder. However, it may also be advantageous to provide not only one MPI injector per cylinder but also one DI injector per cylinder to ensure optimal ignition capability not only during cold starts of the internal combustion engine but also during its normal operation.

[0037] Advantageously, a preheating device is provided, which is particularly preferably designed as an electrothermal pin. The preheating device is arranged upstream of the control device, especially within the connecting passage, and is preferably used to heat the fuel and / or air and / or fuel-air mixture during cold starts of the internal combustion engine. During normal operation of the internal combustion engine, the preheating device is generally not used. The preheating device, in the form of a electrothermal pin, is particularly arranged in a hole within the cylinder head and extends into the connecting passage. A recess for housing the preheating device may also be formed during the casting of the cylinder head. With this arrangement of the preheating device, a sufficiently high temperature level can be obtained in the pre-combustion chamber, thereby enabling stable combustion within the pre-combustion chamber.

[0038] Another advantage is the presence of an additional ignition device within the combustion chamber. That is, in addition to the ignition device in the pre-combustion chamber, an additional ignition device is installed in the combustion chamber, resulting in at least two ignition devices. This additional ignition device, in particular, allows air to enter the combustion chamber and improves the cold-start performance of the internal combustion engine.

[0039] Advantageously, in the internal combustion engine of the present invention, the pre-combustion chamber and the connecting passage are designed to be integrated with the cylinder head. That is, preferably no additional components are required, thereby reducing costs. The connecting passage is preferably simply cast into the cylinder head during casting, and it can also be drilled into it afterward. Attached Figure Description

[0040] Other features, advantages, and functions are derived from the embodiments shown below. These are illustrated in the figures referred to here:

[0041] Figure 1 A partial cross-sectional view of the internal combustion engine of the present invention is shown;

[0042] Figure 2 A schematic diagram of an internal combustion engine is shown;

[0043] Figure 3 A cross-sectional view of a control device designed as a check valve is shown. Detailed Implementation

[0044] exist Figure 1 A portion of the internal combustion engine 1 of the present invention is shown in a longitudinal cross-sectional view. Figure 1 The diagram shows a single-cylinder internal combustion engine or cylinder 3 together with the cylinder head 2 disposed above it. However, the internal combustion engine 1 according to the invention may preferably also have more than one cylinder 3, for example, three or four or more cylinders 3. Therefore Figure 2 An example is shown: a 4-cylinder internal combustion engine 1. For example... Figure 1 The partial diagram shown will subsequently be multiplied according to the number of cylinders. The internal combustion engine has a cylinder head 2 and a cylinder block 13, wherein cylinder 4 is arranged within the cylinder block 13. Other details are omitted for simplicity. Figure 2 It is not shown or can not be seen in the text.

[0045] The internal combustion engine 1 of the present invention includes a cylinder head 2 and a cylinder 3, wherein a combustion chamber 4 is disposed in the cylinder 3. A pre-combustion chamber 5 is also provided, which is generally vertically adjacent to and opens into the combustion chamber 4. The pre-combustion chamber 5 includes an ignition device 6 for igniting a combustible mixture, particularly composed of fuel and air.

[0046] The cylinder head 2 is also equipped with an air intake duct 7 for inputting air and a water jacket 13 for cooling the cylinder head 2.

[0047] The intake duct 7 is connected to the pre-combustion chamber 5 via a connecting channel 8, allowing air to flow from the intake duct 7 into the pre-combustion chamber 5. To control the flow between the intake duct 7 and the pre-combustion chamber, a valve-shaped control device 9 is installed in the connecting channel 8. The control device 9 is preferably designed as a check valve to prevent backflow from the pre-combustion chamber 5 into the intake duct 7.

[0048] Downstream of the connecting passage 8, the intake duct 7 splits into two sub-intake ducts, which lead into the combustion chamber 4. The connecting passage 8 therefore branches off from the intake duct 7 into the sub-intake ducts upstream of this split. To provide optimal encapsulation, the connecting passage 8 leads into the pre-combustion chamber within the passage partition walls of the two sub-intake ducts.

[0049] A multi-point injector 10 is also arranged in the intake duct, through which fuel enters the intake duct 7 and from there enters the combustion chamber 4 as a fuel-air mixture, wherein another ignition device is provided in the combustion chamber.

[0050] The fuel-air mixture also enters the pre-combustion chamber 5 through the connecting passage 8, where it is ignited by the ignition device 6. Therefore, in order to provide an ignitable mixture in the pre-combustion chamber 5, an injection device 10 that is already present in the intake passage 7 is used.

[0051] In order to place the material in the connecting channel 8 at a specified temperature, a preheating device 12 is provided, which is preferably designed as an electric heating element.

[0052] Figure 3 A cross-sectional view of a control device 9 designed as a check valve is shown. The check valve includes a valve body 21 with flow holes 31 and 41 at its ends. Gaseous and / or liquid media can flow through the check valve from the first flow hole 31 toward the second flow hole 41 via the flow holes 31 and 41. The check valve also includes a spring 51 and a closing device 61 having a valve disc 71. The closing device 61 is connected to the spring 51 at its first end, allowing the valve disc 71, located at its second end, to be placed in a closed position. The closing device 61 also includes a partition 81 disposed upstream of the valve disc 71 and downstream of the spring 51.

[0053] The check valve is designed to allow the medium to flow in only one direction. For this purpose, a valve seat 91 is provided in the area of ​​the second flow orifice 41, with the valve disc 71 abutting against it downstream in the closed position. Similarly, a baffle 81 abuts against another valve seat 110 in the closed position. This design of the check valve prevents reverse flow of the medium. The two valve seats 91 and 110 are formed by the deposition of material in the valve body 21.

[0054] Valve disc 71 is part of the closure device 61 and is generally longitudinally oriented, wherein valve disc 71 is arranged at the second end. Baffle 81 is arranged generally centrally on the closure device 61. A chamber 111 is formed between valve disc 71 and baffle 81, through which the medium flows when the closure device 61 is open for flow.

[0055] If a medium with sufficient pressure is applied to the diaphragm 81, the diaphragm is pushed in the flow direction, and the valve disc 71 and thus the entire closure device 61 are opened: the medium can now flow through the check valve. If the pressure drops again or falls below a specified value, the closure device 61 is moved back to the closed position by the spring member 51.

Claims

1. An externally ignited internal combustion engine (1), comprising a cylinder head (2) and at least one cylinder (3) having a combustion chamber (4), wherein, Within the cylinder head (2), each cylinder (3) is provided with a pre-combustion chamber (5) that leads into the combustion chamber (4) and has at least one ignition device (6) and at least one intake manifold (7). Its characteristic is that it is provided with a connecting channel (8) together with a control device (9) disposed in the connecting channel (8), wherein the connecting channel connects the air intake (7) and the pre-combustion chamber (5) in a circulating manner. The air intake (7) has two sub-intake passages connected to a channel partition wall between the sub-intake passages, wherein the connecting passage (8) leads into the pre-combustion chamber (5) within the channel partition wall.

2. The internal combustion engine (1) according to claim 1, characterized in that, The pre-combustion chamber (5) has no injection device.

3. The internal combustion engine (1) according to claim 1 or 2, characterized in that, The control device (9) is designed with a check valve or a throttle valve as the valve.

4. The internal combustion engine (1) according to claim 3, characterized in that, The control device (9) is designed as a check valve with a valve body (21) having two flow holes (31; 41), wherein the check valve is capable of having a medium flow through the first flow hole (31) toward the second flow hole (41), and also includes a spring (51) and a closing device (61) with a valve disc (71), wherein the first end of the closing device (61) is connected to the spring (51), the valve disc (71) is arranged at the second end of the closing device (61), wherein the valve disc (71) opens the second flow hole (41) from a specified pressure, wherein the closing device (61) includes a partition (81), wherein the partition (81) is arranged upstream of the valve disc (71).

5. The internal combustion engine (1) according to claim 4, characterized in that, The diaphragm (81) blocks the flow of medium through the check valve in the closed position and opens the flow of medium from a specified pressure differential, wherein the pressure differential for opening the diaphragm (81) is less than the pressure differential for opening the valve disc (71).

6. The internal combustion engine (1) according to claim 4, characterized in that, The diameter of the partition (81) is larger than the diameter of the valve disc (71).

7. The internal combustion engine (1) according to claim 4, characterized in that, In the closed position, the valve disc (71) rests at least against the valve seat (91) of the valve body (21).

8. The internal combustion engine (1) according to claim 7, characterized in that, In the closed position, the baffle (81) rests against at least another valve seat (110) of the valve body (21).

9. The internal combustion engine (1) according to claim 4, characterized in that, A chamber (111) is formed between the valve disc (71) and the partition (81).

10. The internal combustion engine (1) according to claim 1 or 2, characterized in that, in The intake manifold (7) provides at least one first injection device (10) for each cylinder (3), wherein the first injection device (10) is designed as a multi-point injector.

11. The internal combustion engine (1) according to claim 10, characterized in that, At least one second injection device (11) is provided for direct injection into the combustion chamber (4).

12. The internal combustion engine according to claim 1 or 2, characterized in that, A preheating device (12) is provided, which is arranged in the communication channel (8) upstream of the control device (9) and is used to heat fuel and / or air and / or fuel-air mixture during cold start of the internal combustion engine.

13. The internal combustion engine according to claim 1 or 2, characterized in that, At least one additional ignition device is provided in the combustion chamber (4).

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