Detection system for auxiliary-chamber type internal combustion engine

Abstract

To provide a detection system for an auxiliary-chamber type internal combustion engine that detects vibration to detect the vibration due to a flame that is jetted from an auxiliary combustion chamber.SOLUTION: A detection system for an auxiliary chamber type internal combustion engine includes: a main combustion chamber; an auxiliary combustion chamber installed while being isolated from the main combustion chamber via a wall; an ignition device disposed inside the auxiliary combustion chamber; and a detector for detecting first vibration due to a flame that is jetted from the auxiliary combustion chamber and second vibration due to abnormal combustion in the main combustion chamber.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a detection system for an internal combustion engine with a separate combustion chamber. [Background technology]

[0002] Conventionally, a pre-chamber type internal combustion engine having a main combustion chamber and a pre-chamber provided adjacent to the main combustion chamber has been proposed (see, for example, Patent Document 1). In such a pre-chamber type internal combustion engine, an air-fuel mixture is formed from fuel injected into the main combustion chamber. The formed air-fuel mixture is supplied to the pre-chamber through a communication passage, and is ignited by a spark plug in the pre-chamber to form a flame. The flame formed in the pre-chamber is injected into the main combustion chamber through the communication passage, and ignites the air-fuel mixture in the main combustion chamber. In this way, the combustion speed in the main combustion chamber can be increased by injecting the flame formed in the pre-chamber into the main combustion chamber. This allows operation with a leaner air-fuel ratio, and improves fuel efficiency.

[0003] Furthermore, Patent Document 1 discloses a technique for detecting the state of the flame injected from the pre-combustion chamber. In recent years, there has been a demand for detecting the state of the pre-combustion chamber in this manner. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-67223 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Document 1 discloses a technique for detecting the state of the flame injected from the pre-combustion chamber using the current waveform generated by the ignition coil, but does not disclose any method other than detection using the current waveform of the ignition coil.

[0006] An object of the present disclosure is to provide a detection system for a pre-combustion chamber type internal combustion engine that detects vibrations caused by flames injected from the pre-combustion chamber by detecting vibrations. [Means for solving the problem]

[0007] The detection system for a pre-combustion chamber type internal combustion engine according to the present disclosure includes a main combustion chamber, a pre-combustion chamber separated from the main combustion chamber by a wall, an ignition device disposed within the pre-combustion chamber, and a detection device that detects a first vibration caused by a flame injected from the pre-combustion chamber and a second vibration caused by abnormal combustion in the main combustion chamber.

[0008] This detection system for a pre-chamber type internal combustion engine detects vibrations in the pre-chamber type internal combustion engine, and the detection device that detects abnormalities in combustion in the main combustion chamber can also detect vibrations caused by the flame injected from the pre-chamber. Effect of the Invention

[0009] According to the present disclosure, it is possible to provide a detection system for a pre-combustion chamber type internal combustion engine that detects vibrations caused by flames injected from the pre-combustion chamber by detecting vibrations. [Brief description of the drawings]

[0010] [Figure 1] 1 is a system diagram of a detection system for an internal combustion engine with a separate chamber according to an embodiment of the present disclosure; [Diagram 2] 1 is a diagram showing a schematic configuration of a pre-chamber type internal combustion engine according to an embodiment of the present disclosure; [Diagram 3] 4A-4C are diagrams illustrating a first vibration, a second vibration, and a third vibration according to an embodiment of the present disclosure. [Figure 4] 1 is a diagram showing a schematic configuration of a control device for a pre-chamber type internal combustion engine according to an embodiment of the present disclosure; [Diagram 5] 4 is a flowchart showing a control procedure of a control device using a detection system for an internal combustion engine with a pre-chamber according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0012] As shown in FIG. 1 and FIG. 2, the detection system 2 of the auxiliary combustion chamber 1 includes a main combustion chamber 4, an auxiliary combustion chamber 6, a plurality of communication passages 8, an ignition plug (an example of an ignition device) 10, a fuel injection valve 12, and a knock sensor 14 and a control device 16 as examples of detection devices. The detection system 2 of the auxiliary combustion chamber 1 may also include a supercharger 18, an exhaust gas recirculation device 20, various devices for improving the performance of the auxiliary combustion chamber 1, and sensors for detecting the state of the auxiliary combustion chamber 1, such as an airflow sensor 22. In this embodiment, the auxiliary combustion chamber 1 is an in-line internal combustion engine in which a plurality of cylinders N are arranged in series. The main combustion chamber 4, the auxiliary combustion chamber 6, a plurality of communication passages 8, the ignition plug 10, and the fuel injection valve 12 are provided for each cylinder N arranged in series. However, the arrangement of the cylinders N is not limited to this, and the auxiliary combustion chamber 1 may be a V-type or horizontally opposed type.

[0013] As shown in FIG. 2, the main combustion chamber 4 is a space surrounded by the cylinder 101a of the cylinder block 101, the cylinder head 102, and the piston 103. In this embodiment, the main combustion chamber 4 has a pent roof shape in which two slopes are formed toward the intake port 105 side and the exhaust port 110 side of the cylinder head 102, which will be described later. The main combustion chamber 4 is connected to the intake port 105 via the intake valve 104. As shown in FIG. 1, the intake port 105 is connected to, for example, the intake passage 24, the throttle valve 26, the intercooler 28, and the air cleaner 30. However, the sub-chamber type internal combustion engine 1 only needs to be able to supply intake air to the intake port 105, and may not, for example, be provided with the intercooler 28. The intake valve 104 is driven by an intake cam 113. Also, as shown in FIG. 2, the main combustion chamber 4 is connected to the exhaust port 110 via the exhaust valve 109. 1, the exhaust port 110 is connected to the exhaust passage 32 and the exhaust purification catalyst 34. The exhaust valve 109 is driven by an exhaust cam 114.

[0014] As shown in FIG. 2, the auxiliary combustion chamber 6 is provided adjacent to the main combustion chamber 4 at the top of the pent roof shape, and has a space surrounded by the auxiliary combustion chamber wall 61. The auxiliary combustion chamber 6 protrudes from the cylinder head 102 toward the main combustion chamber 4, and is provided separated from the main combustion chamber 4 via the auxiliary combustion chamber wall 61. In this embodiment, the auxiliary combustion chamber 6 is provided at approximately the center of the intersection line (ridge line) of the slope of the pent roof shape of the main combustion chamber 4. However, the auxiliary combustion chamber 6 may be provided offset from approximately the center of the main combustion chamber 4 toward the inner wall surface of the cylinder 101a. In this embodiment, the auxiliary combustion chamber wall 61 is formed, for example, in a circular cross section and a hemispherical bottom 61a. However, the auxiliary combustion chamber wall 61 is not limited to this and can be changed to various shapes.

[0015] The spark plug 10 is provided in approximately the center of the pre-combustion chamber 6 and ignites the mixture in the pre-combustion chamber 6. A central electrode 10a of the spark plug 10 protrudes into the pre-combustion chamber 6. In this embodiment, the central electrode 10a is provided in approximately the center of the pre-combustion chamber 6. However, the central electrode 10a may be disposed offset from approximately the center of the pre-combustion chamber 6.

[0016] A plurality of communication passages 8 are provided in the bottom 61a of the auxiliary combustion chamber wall 61. The communication passages 8 communicate between the main combustion chamber 4 and the auxiliary combustion chamber 6, and guide the air-fuel mixture in the main combustion chamber 4 to the auxiliary combustion chamber 6. In this embodiment, for example, six communication passages 8 are provided.

[0017] The volume of the auxiliary combustion chamber 6 is smaller than that of the main combustion chamber 4, and the flame of the mixture ignited by the spark plug 10 quickly propagates into the auxiliary combustion chamber 6. The auxiliary combustion chamber 6 injects the flame generated in the auxiliary combustion chamber 6 into the main combustion chamber 4 via a communication passage 8. The flame injected into the main combustion chamber 4 ignites the mixture in the main combustion chamber 4 and burns it. That is, in the auxiliary combustion chamber type internal combustion engine 1, the combustion space 3 is formed by including the main combustion chamber 4 and the auxiliary combustion chamber 6.

[0018] The fuel injection valve 12 is provided facing the main combustion chamber 4 and injects fuel into the main combustion chamber 4. The fuel injection valve 12 is disposed on the intake valve 104 side of the cylinder head 102. The fuel injection valve 12 forms a mixture in the main combustion chamber 4 by supplying fuel in a spray form. The fuel injection valve 12 also supplies fuel to the auxiliary combustion chamber 6 through the communication passage 8 by injecting fuel into the main combustion chamber 4. The fuel injection valve 12 forms a mixture in the auxiliary combustion chamber 6 by supplying fuel to the auxiliary combustion chamber 6. In this embodiment, the tip of the fuel injection valve 12 is provided facing the main combustion chamber 4 and injects fuel directly into the main combustion chamber 4. That is, the auxiliary combustion chamber type internal combustion engine 1 is a direct injection type internal combustion engine. As shown in FIG. 1, the fuel injection valve 12 is electrically connected to a control device 16, and the control device 16 controls the injection amount and injection timing.

[0019] The knock sensor 14 is a sensor that detects vibrations of the main combustion chamber 4. In this embodiment, the knock sensor 14 is attached to the cylinder block 101. The knock sensor 14 detects vibrations of the main combustion chamber 4 that are transmitted to the cylinder block 101, and transmits the detected vibrations to the control device 16.

[0020] The control device 16 detects a first vibration caused by the flame injected from the auxiliary combustion chamber 6, a second vibration caused by abnormal combustion in the main combustion chamber 4, and a third vibration in a frequency band including the first and second vibrations, using the vibrations acquired by the knock sensor 14. In this embodiment, the control device 16 further detects a fourth vibration caused by the communication passage 8.

[0021] The first vibration caused by the flame injected from the auxiliary combustion chamber 6 is a vibration caused by jet ignition that occurs in the process of the flame ignited in the auxiliary combustion chamber 6 being injected from the multiple communication passages 8 toward the main combustion chamber 4. There are various factors that can be considered as vibration caused by jet ignition, for example, the variation of the flame injected from the multiple communication passages 8. In the case of the variation of the flame, the flame propagation speed in the main combustion chamber 4 is affected by the difference in the size of the flame or the difference in the speed of the flame. If a part of the flame injected from the multiple communication passages 8 is small, the flame propagation speed of that part will be slow. This causes air column vibration in the main combustion chamber 4. This vibration is the first vibration. The first vibration is mainly in the first frequency band of 5 kHz to 8 kHz.

[0022] The second vibration caused by abnormal combustion occurring in the main combustion chamber 4 is a vibration caused by knocking. Knocking indicates an abnormal combustion state in which the mixture in the main combustion chamber 4 partially self-ignites. The second vibration is mainly in a second frequency band between 5 kHz and 14 kHz, which has a higher maximum value than the first frequency band.

[0023] The third vibration includes the first frequency band and the second frequency band, and has a minimum frequency lower than the first and second frequency bands and a maximum frequency higher than the second frequency band. That is, the third vibration is a vibration in the third frequency band that is wider than the second frequency band. The third vibration is mainly a vibration in a frequency band of 4 kHz to 20 kHz. In the third frequency band, in addition to the vibration caused by jet ignition and the vibration caused by knocking, it is possible to detect the vibration caused by the sludge sound of the piston 103 and the vibration caused by the sound of a high-pressure fuel pump (not shown) that supplies high-pressure fuel to the fuel injection valve 12 in the third frequency band. In this way, the control device 16 prevents the oversight of the detection of the vibration caused by jet ignition and the knocking by detecting the third vibration in a frequency band wider than the first and second vibrations.

[0024] The fourth vibration caused by the communication passage 8 is a vibration that occurs due to an abnormality such as a blocked state of the communication passage 8. More specifically, for example, when the communication passage 8 is blocked, vibration occurs when the communication passage 8 guides the air-fuel mixture in the main combustion chamber 4 to the auxiliary combustion chamber 6 before the ignition timing. This vibration is the fourth vibration. The fourth vibration is mainly in a fourth frequency band that is equal to or higher than 4 kHz and lower than 7 kHz.

[0025] However, the first frequency band caused by jet ignition and the second frequency band caused by knocking partially overlap, so there is a risk that the first vibration caused by jet ignition may be erroneously detected as the second vibration caused by knocking.

[0026] 3, the first vibration is likely to occur in a first period from the ignition timing of the spark plug 10. On the other hand, the second vibration is likely to occur after the first period, that is, in a second period that starts from a crank angle that is retarded from the start timing of the first period. Therefore, the control device 16 detects the first vibration in the first period and detects the second vibration in the second period.

[0027] In this embodiment, the first period is the period from the ignition timing to when the in-cylinder pressure of the main combustion chamber 4 reaches its maximum. The ignition timing (crank angle at which ignition occurs) varies depending on the rotation speed and load of the auxiliary combustion chamber type internal combustion engine 1. Therefore, the start timing (start crank angle) of the first period varies depending on the rotation speed and load. The end timing (end crank angle) of the first period may be retarded or advanced from the position (crank angle) at which the in-cylinder pressure reaches its maximum, taking into account the volume of the auxiliary combustion chamber 6, the volume of the cylinder 101a (displacement of the auxiliary combustion chamber type internal combustion engine 1), the intake amount, the fuel injection amount, etc.

[0028] In this embodiment, the second period is a period from when the cylinder pressure becomes maximum after the first period until the cylinder pressure finishes decreasing. However, the start time of the second period may be retarded or advanced from the position (crank angle) where the cylinder pressure becomes maximum, similarly to the end time of the first period, in consideration of the volume of the auxiliary combustion chamber 6, the volume of the cylinder 101a (displacement of the auxiliary combustion chamber type internal combustion engine 1), the intake air amount, the fuel injection amount, etc. Furthermore, the end time of the second period may also be retarded or advanced from the position where the cylinder pressure finishes decreasing, in consideration of the volume of the auxiliary combustion chamber 6, the volume of the cylinder 101a (displacement of the auxiliary combustion chamber type internal combustion engine 1), the intake air amount, the fuel injection amount, etc.

[0029] Furthermore, the control device 16 may change at least one of the range of the first frequency band (the range from the minimum frequency to the maximum frequency of the first frequency band) and the range of the second frequency band (the range from the minimum frequency to the maximum frequency of the second frequency band) depending on the rotation speed of the pre-combustion engine 1 or the load of the pre-combustion engine 1. In this case, the control device 16 may set the first frequency band and the second frequency band to be frequency bands that do not overlap.

[0030] The first vibration caused by jet ignition has a larger amplitude (intensity) as the rotation speed of the pre-chamber type internal combustion engine 1 or the load of the pre-chamber type internal combustion engine 1 increases. Therefore, even if the control device 16 changes the first frequency band to a narrower frequency band, the control device 16 can easily detect the first vibration. For example, the control device 16 may change the first frequency band to 5 kHz or more and less than 6 kHz according to the rotation speed or load of the pre-chamber type internal combustion engine 1. In this case, the control device 16 may change the second frequency band to 6 kHz or more and 14 kHz or less. This can prevent erroneous detection of knocking and vibration caused by jet ignition. The control device 16 may change the first frequency band according to the temperature of the main combustion chamber 4 instead of the load. The control device 16 may also store a map of the first frequency band according to the rotation speed of the pre-chamber type internal combustion engine 1, the load of the pre-chamber type internal combustion engine 1, or the temperature of the main combustion chamber 4. The control device 16 may change the range of the first frequency band based on this map.

[0031] The third period is a period including the first period and the second period. In this embodiment, the third period is a period from the start of the first period to the end of the second period. However, the third period may be a period longer than this. The control device 16 detects the third vibration during the third period. This makes it possible to prevent the vibration or knocking caused by jet ignition from being overlooked.

[0032] The fourth period is a period before the ignition timing. The start time of the fourth period may be the same as the start time of the compression stroke, or may be advanced or retarded from the start time. The end time of the fourth period may be any time before the ignition timing. The fourth vibration caused by the communication passage 8 occurs before the ignition timing. Therefore, the control device 16 detects the fourth vibration in the fourth period.

[0033] The control device 16 is actually an ECU (Electronic Control Unit) and is configured by a microcomputer including an arithmetic device, a memory, an input / output buffer, etc. The control device 16 controls the various devices based on signals from the various sensors and devices, as well as maps and programs stored in the memory, so that the pre-chamber type internal combustion engine 1 is in a desired operating state. Note that the various controls are not limited to processing by software, and can also be processed by dedicated hardware (electronic circuits).

[0034] As shown in FIG. 4, in this embodiment, the control device 16 obtains vibration from the knock sensor 14, and performs frequency spectrum analysis on the obtained vibration to obtain amplitude (intensity) for each frequency.

[0035] More specifically, for example, in the case where the cylinders N of the pre-chamber type internal combustion engine 1 are four, the control device 16 identifies the cylinders N that are in the compression stroke to the expansion stroke from the four cylinders N. The control device 16 distributes the acquired vibrations as the vibrations of the cylinders N that are in the compression stroke to the expansion stroke. The control device 16 distributes the acquired vibrations to the first period to the fourth period. The control device 16 extracts the first vibration of the first frequency band that occurs in the first period and performs frequency spectrum analysis. In this way, the control device 16 obtains the amplitude (intensity) of the first vibration for each frequency in the first period. Similarly, the control device 16 obtains the amplitude (intensity) of the second vibration for each frequency in the second period, the amplitude (intensity) of the third vibration for each frequency in the third period, and the amplitude (intensity) of the fourth vibration for each frequency in the fourth period. The control device 16 uses the amplitude (intensity) for each frequency to perform judgment of vibration due to jet ignition, knocking, abnormality of the communication passage 8, and the like.

[0036] Since such calculations impose a large load, the control device 16 of this embodiment has an electronic circuit that executes these calculations, which enables the control device 16 to perform calculations quickly.

[0037] Next, a control procedure executed by the control device 16 will be described with reference to the flowchart of Fig. 5. The control device 16 starts a control operation when an ignition switch (not shown) is turned on.

[0038] In step S1, the control device 16 acquires vibration from the knock sensor 14. In step S2, when the control device 16 acquires the vibration, the control device 16 executes the above-mentioned calculation. After executing the calculation, the control device 16 advances the process to step S2.

[0039] In step S2, the control device 16 determines whether or not a third vibration is detected in the third period. The control device 16 may determine that the third vibration is detected when a vibration of a predetermined amplitude or more in the third frequency band is detected in the third period. When the control device 16 detects the third vibration in the third period (YES in step S2), the control device 16 proceeds to step S3.

[0040] In step S3, the control device 16 determines whether or not a first vibration is detected in the first period. The control device 16 may determine that the first vibration is detected when a vibration of a first frequency band equal to or greater than a predetermined amplitude is detected in the first period. When the control device 16 detects the first vibration in the first period (step S3: YES), the control device 16 advances the process to step S4.

[0041] In step S4, the control device 16 determines whether or not a second vibration is detected in the second period. The control device 16 may determine that the second vibration is detected when a vibration of a predetermined amplitude or more in the second frequency band is detected in the second period. If the control device 16 does not detect the second vibration in the second period (NO in step S4), the control device 16 proceeds to step S5.

[0042] In step S5, the control device 16 determines that vibration due to jet ignition has occurred. That is, when the first vibration is detected only in the first period, the control device 16 can determine that only vibration due to jet ignition has occurred. When the control device 16 determines that vibration due to jet ignition has occurred, the control device 16 advances the process to step S1.

[0043] In step S2, when the control device 16 determines that the third vibration has not been detected in the third period (NO in step S2), the control device 16 advances the process to step S6.

[0044] In step S6, the control device 16 determines whether or not a fourth vibration has been detected in the fourth period. The control device 16 may determine that the fourth vibration has been detected if a vibration of a predetermined amplitude or more in the fourth frequency band is detected in the fourth period. If the control device 16 detects the fourth vibration in the fourth period (YES in step S6), the control device 16 proceeds to step S7.

[0045] In step S7, the control device 16 determines that an abnormality has occurred in the communication passage 8. That is, when the fourth vibration is detected only in the fourth period, the control device 16 can determine that an abnormality has occurred only in the communication passage 8. When the control device 16 determines that an abnormality has occurred in the communication passage 8, the control device 16 advances the process to step S1.

[0046] In step S6, if the control device 16 determines that the fourth vibration has not been detected in the fourth period (NO in step S6), the control device 16 advances the process to step S1.

[0047] In step S3, when the control device 16 determines that the first vibration has not been detected in the first period (NO in step S3), the control device 16 advances the process to step S8.

[0048] In step S8, the control device 16 determines whether or not a second vibration is detected in the second period. The control device 16 may determine that the second vibration is detected when a vibration of a predetermined amplitude or more in the second frequency band is detected in the second period. When the control device 16 detects the second vibration in the second period (YES in step S8), the control device 16 proceeds to step S9.

[0049] In step S9, the control device 16 determines that knocking has occurred (knock determination). That is, when the second vibration is detected only in the second period, the control device 16 can determine that only knocking has occurred. When the control device 16 determines that knocking has occurred, the process proceeds to step S10.

[0050] In step S10, the control device 16 suppresses the output of the pre-chamber type internal combustion engine 1. When a knock determination is made, the control device 16 may retard the ignition timing. In addition, the control device 16 may also execute other controls to reduce the output of the pre-chamber type internal combustion engine 1, such as control to reduce the opening of the throttle valve 26 and control to reduce the supercharging pressure of the supercharger 18, at the same time as the ignition retard. After suppressing the output of the pre-chamber type internal combustion engine 1, the control device 16 advances the process to step S1.

[0051] In step S4, when the control device 16 determines that the second vibration has been detected in the second period (step S4: YES), the control device 16 may proceed to step S9 and determine that knocking has occurred (knock determination). If the second vibration is detected in the engine 10, there is a possibility that both vibration due to jet ignition and knocking are occurring. Therefore, it is preferable that the control device 16 executes a knock determination and suppresses the output of the pre-chamber type internal combustion engine 1 (see step S10).

[0052] In step S8, when the control device 16 determines that the second vibration has not been detected in the second period (NO in step S8), the control device 16 advances the process to step S11.

[0053] In step S11, the control device 16 determines that there is a possibility of an abnormality. In this case, the control device 16 may proceed to the process of step S1, and if it is determined multiple times that there is a possibility of an abnormality, it may perform a knock determination. Alternatively, the output of the pre-chamber type internal combustion engine 1 may be suppressed at the time when it is determined in step S11 that there is a possibility of an abnormality.

[0054] As described above, according to the detection system 2 for the pre-chamber type internal combustion engine 1 of the present disclosure, the knock sensor 14, which detects abnormalities in combustion in the main combustion chamber 4 by detecting vibrations in the pre-chamber type internal combustion engine 1, can separately detect vibrations caused by the flame injected from the pre-chamber 6 and vibrations caused by knocking in the main combustion chamber 4. The knock sensor 14 may be a known knock sensor, and according to the detection system 2 for the pre-chamber type internal combustion engine 1 of the present disclosure, it is possible to detect vibrations caused by the flame injected from the pre-chamber 6 without providing a new sensor.

[0055] <Other embodiments> Although the embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention. In particular, the multiple modifications described in this specification can be arbitrarily combined as necessary. In addition, the internal combustion engine described in this embodiment can also be applied to a plug-in hybrid electric vehicle (PHEV) that can be externally charged or externally powered.

[0056] (a) In the above embodiment, an example has been described in which vibrations are detected by dividing the period into four periods, namely, the first period, the second period, the third period, and the fourth period, but vibrations may be detected by dividing each period into smaller periods, for example. The number of periods into which the period is divided can be changed as appropriate in accordance with the characteristics of the pre-chamber type internal combustion engine 1.

[0057] (b) In the above embodiment, the auxiliary combustion chamber type internal combustion engine 1 has been described using an example in which the fuel injection valve 12 is provided facing the main combustion chamber 4 and injects fuel into the main combustion chamber 4, but the present disclosure is not limited to this. The auxiliary combustion chamber type internal combustion engine 1 may have the fuel injection valve 12 provided in the space surrounded by the auxiliary combustion chamber wall 61 of the auxiliary combustion chamber 6. Also, a direct injection type first fuel injection valve and a second fuel injection valve provided in the space surrounded by the auxiliary combustion chamber wall 61 of the auxiliary combustion chamber 6 may be provided for each cylinder N. [Explanation of symbols]

[0058] 1: Pre-chamber internal combustion engine, 2: Detection system, 4: Main combustion chamber 6: auxiliary combustion chamber, 8: communication passage, 14: knock sensor, 16: control device

Claims

1. A main combustion chamber; an auxiliary combustion chamber separated from the main combustion chamber via a wall; an ignition device disposed in the auxiliary combustion chamber; a detection device that detects a first vibration caused by a flame injected from the auxiliary combustion chamber and a second vibration caused by abnormal combustion in the main combustion chamber; Equipped with Detection system for pre-chamber internal combustion engines.

2. the detection device detects the first vibration during a first period from an ignition timing by the ignition device, and detects the second vibration during a second period after the first period.

2. The detection system for an internal combustion engine with a separate chamber according to claim 1.

3. The first vibration is a vibration in a first frequency band, and the second vibration is a vibration in a second frequency band having a higher maximum value than the first frequency band.

3. The detection system for an internal combustion engine with a separate chamber according to claim 2.

4. The detection device detects a third vibration including the first frequency band and the second frequency band during a third period including the first period and the second period.

4. The detection system for an internal combustion engine with a separate chamber according to claim 3.

5. The auxiliary combustion chamber has a plurality of communication passages in the wall that communicate the main combustion chamber and the auxiliary combustion chamber, When the first vibration is detected during the first period and the second vibration is not detected during the second period, the detection device determines that the vibration is caused by variation in flames injected from the multiple communication passages toward the main combustion chamber.

3. The detection system for an internal combustion engine with a separate chamber according to claim 2.

6. The auxiliary combustion chamber has a communication passage in the wall that communicates the main combustion chamber with the auxiliary combustion chamber, The detection device detects a fourth vibration caused by the communication passage during a fourth period including a period before an ignition timing by the ignition device.

6. A detection system for an internal combustion engine with a pre-chamber according to claim 1.

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