Misfire treatment method for engine with openable and closable active pre-combustion chamber

Abstract

The invention provides a misfire treatment method for an engine with an openable active pre-combustion chamber, which comprises the following steps: acquiring an instantaneous angular velocity value of a crankshaft based on an ignition excess air coefficient value of a pre-combustion chamber and an ignition excess air coefficient value of a main combustion chamber in combination with a rotating speed sensor, and judging whether a misfire phenomenon exists or not based on the angular velocity value; if yes, whether ignition occurs in the pre-combustion chamber or not is judged based on a thermocouple on a spark plug of the pre-combustion chamber, and the position where the fire phenomenon occurs is judged; and if the misfire phenomenon occurs in the pre-combustion chamber, the excess air coefficient value of the oxygen sensor is obtained, and the fuel injector is closed so that the excess air coefficient value of the oxygen sensor can be higher than the ignition excess air coefficient value of the main combustion chamber till the ignition condition is recovered. According to the method, whether the misfire phenomenon occurs or not can be rapidly judged, the misfire position can be determined, stable operation of the engine is achieved by adjusting the excess air coefficient value of the oxygen sensor, and the service life of the engine is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of internal combustion engines, and in particular to a method for handling misfires in an engine with an openable and closable active pre-combustion chamber. Background Art

[0002] As the global demand for environmental protection and energy efficiency increases, internal combustion engine technology continues to develop to meet more stringent emission standards and higher fuel economy requirements. As a new type of internal combustion engine technology, the active pre-combustion chamber engine has gradually attracted widespread attention due to its efficient combustion control ability and low emission characteristics during the combustion process. The active pre-combustion chamber engine ignites a small amount of fuel in the pre-combustion chamber first, and uses the high-temperature and high-pressure flame generated by the initial combustion to spray into the main combustion chamber, thereby causing the mixture in the main combustion chamber to burn quickly and evenly. However, this ignition method faces certain problems. The ventilation effect in the pre-combustion chamber is not ideal, resulting in a large amount of residual exhaust gas in the pre-combustion chamber. In addition, the limited space of the pre-combustion chamber makes it easy for the oil beam to hit the wall during fuel injection, resulting in a significant increase in the amount of wet wall, resulting in poor mixing of the fuel in the pre-combustion chamber, which is very likely to cause misfires in the pre-combustion chamber.

[0003] Misfire refers to the failure of the combustion process in one or more cylinders of the engine to complete normally or to proceed as expected. This is usually caused by ignition failure, abnormal fuel supply, or too lean or too rich mixture. Compared with traditional internal combustion engines, the pre-combustion chamber space of the pre-combustion chamber engine is relatively small, and due to the special structure of the pre-combustion chamber, the gas in the pre-combustion chamber cannot be fully discharged during the exhaust stroke, which makes the problem more serious once a misfire occurs, especially when the misfire is caused by too rich mixture. If the misfire is not discovered and handled in time, in the subsequent combustion cycle, the mixture in the pre-combustion chamber may be further enriched due to the continued accumulation of fuel.

[0004] In the prior art, if a misfire is not detected and handled in a timely manner, in the subsequent combustion cycle, the mixed gas in the pre-combustion chamber may be further enriched due to the continued accumulation of fuel. This situation will cause misfires to occur repeatedly, thereby affecting the combustion stability and efficiency of the entire engine, and may ultimately lead to performance degradation or increased emissions. Summary of the invention

[0005] Based on this, the object of the present invention is to provide a misfire treatment method for an engine with an openable and closable active pre-combustion chamber, so as to solve the deficiencies in the above-mentioned prior art.

[0006] The present invention provides a method for handling misfire of an engine with an openable and closable active pre-combustion chamber, the method comprising: Determine the ignition temperature threshold, the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value according to the working state of the engine; Based on the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value and in combination with a speed sensor, an instantaneous angular velocity value of the crankshaft is obtained, and based on the angular velocity value, whether there is a misfire phenomenon is determined; If yes, determine whether there is ignition in the pre-combustion chamber based on the thermocouple on the pre-combustion chamber spark plug, and determine the location where the misfire occurs; If the misfire occurs in the pre-combustion chamber, the excess air coefficient value of the oxygen sensor is obtained, and the injector is closed so that the excess air coefficient value of the oxygen sensor is higher than the main combustion chamber ignition excess air coefficient value until the ignition condition is restored.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: by obtaining the instantaneous angular velocity value of the crankshaft through the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value in combination with the speed sensor, it is possible to determine whether a misfire has occurred, and by determining the location of the misfire through a thermocouple, the misfired combustion chamber can be determined, and rapid recovery after the misfire can be achieved, reducing the impact on subsequent cycles, and by making the excess air coefficient value of the oxygen sensor higher than the excess air coefficient value of the main combustion chamber ignition, engine damage due to misfire can be avoided, thereby achieving stable engine operation, extending the service life of the engine, and also achieving automatic control of the stable operation of the engine.

[0008] Furthermore, the basic parameters of the engine include cylinder diameter, stroke and compression ratio; The working state of the engine includes speed, load, intake air temperature, intake air pressure, coolant temperature and confirmation of initial value; The confirmed initial values ​​include an ignition temperature threshold, a pre-combustion chamber ignition excess air coefficient value, and a main combustion chamber ignition excess air coefficient value.

[0009] Furthermore, the step of determining whether the pre-combustion chamber is ignited based on the thermocouple on the spark plug of the pre-combustion chamber includes: Measuring the ignition temperature of the pintle tip based on a thermocouple sensor, and judging whether there is a fire in the pre-combustion chamber according to the ignition temperature; If the ignition temperature is lower than the currently set threshold, it is determined that the pre-combustion chamber is misfiring.

[0010] Furthermore, after the step of determining the location where the fire occurs, the method further includes: If the misfire occurs in the main combustion chamber, the excess air coefficient value of the oxygen sensor is obtained, and the injection pulse width of the intake port injector is increased so that the excess air coefficient value of the oxygen sensor is lower than the ignition excess air coefficient value of the main combustion chamber.

[0011] Furthermore, after the step of making the excess air coefficient value of the oxygen sensor lower than the ignition excess air coefficient value of the main combustion chamber, the method further includes: Repeat the process of determining the ignition temperature threshold, the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value according to the working state of the engine; obtaining the instantaneous angular velocity value of the crankshaft based on the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value in combination with the speed sensor, and judging whether there is a misfire based on the angular velocity value; if so, judging whether there is ignition in the pre-combustion chamber based on the thermocouple on the pre-combustion chamber spark plug, and judging the location where the misfire occurs.

[0012] Furthermore, after the step of making the excess air coefficient value of the oxygen sensor lower than the ignition excess air coefficient value of the main combustion chamber, the method further includes: The mixture in the main combustion chamber is enriched, and it is determined whether the concentration of the mixture in the main combustion chamber reaches a condition for resuming ignition, and the fuel injection map of the engine is corrected.

[0013] Furthermore, after the step of making the excess air coefficient value of the oxygen sensor higher than the ignition excess air coefficient value of the main combustion chamber, the method further includes: judging that the state of the mixed gas in the pre-combustion chamber has been restored based on the thermocouple sensor in the shaft needle; Repeat the process of determining the ignition temperature threshold, the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value according to the working state of the engine; obtaining the instantaneous angular velocity value of the crankshaft based on the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value in combination with the speed sensor, and judging whether there is a misfire based on the angular velocity value; if so, judging whether there is ignition in the pre-combustion chamber based on the thermocouple on the pre-combustion chamber spark plug, and judging the location where the misfire occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a flow chart of a misfire treatment method of an engine with an openable and closable active pre-combustion chamber in a first embodiment of the present invention; Figure 2 It is a schematic structural diagram of a combustion system in a second embodiment of the present invention.

[0015] Description of main component symbols: 1. Pre-combustion chamber injector; 2. Spark plug; 3. Exhaust valve; 4. Exhaust pipe; 5. Pre-combustion chamber spray hole; 6. Piston; 7. Pre-combustion chamber; 8. Intake duct; 9. Intake duct injector; 10. Intake valve; 11. Main combustion chamber; 12. Pintle; 13. Solenoid valve; 14. Thermocouple.

[0016] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0017] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0018] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0020] Embodiment 1 See also Figure 1 , which shows a misfire treatment method for an engine with an openable and closable active pre-combustion chamber in an embodiment of the present invention, the method comprises steps S1 to S4: S1, determining an ignition temperature threshold, a pre-combustion chamber ignition excess air coefficient value, and a main combustion chamber ignition excess air coefficient value according to the working state of the engine; It should be noted that the operating state of the engine includes speed, load, intake temperature, intake pressure, coolant temperature and confirmed initial value; the confirmed initial value includes ignition temperature threshold t1, pre-combustion chamber ignition excess air coefficient value L1 and main combustion chamber ignition excess air coefficient value L2.

[0021] S2, based on the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value and in combination with a speed sensor, obtaining the crankshaft instantaneous angular velocity value, and judging whether there is a misfire based on the angular velocity value; It should be explained that the occurrence of misfire is determined by combining the excess air coefficient value obtained by the oxygen sensor with the instantaneous angular velocity value of the crankshaft obtained by the speed sensor. This method is an existing mature judgment method and will not be elaborated on here.

[0022] S3, if yes, judging whether there is ignition in the pre-combustion chamber based on the thermocouple on the spark plug of the pre-combustion chamber, and judging the location where the misfire occurs; Specifically, the step S3 includes steps S31 to S32: S31, measuring the ignition temperature of the top end of the shaft pin based on a thermocouple sensor, and judging whether there is a fire in the pre-combustion chamber according to the ignition temperature; S32, if the ignition temperature is lower than the currently set threshold, it is determined that the pre-combustion chamber is misfiring; It needs to be explained that by using the thermocouple arranged on the pre-combustion chamber spark plug, it is possible to determine whether ignition is completed in the pre-combustion chamber, and then to determine the location where the misfire occurs, and the misfire phenomenon is defined as pre-combustion chamber misfire and main combustion chamber misfire.

[0023] It is worth noting that in the specific implementation, a thermocouple sensor inside the shaft needle is used, and the measuring point is located at the top of the shaft needle to determine whether a fire occurs in the pre-combustion chamber. If the measured ignition temperature is lower than the current pre-combustion temperature, it is determined that there is a fire in the pre-combustion chamber.

[0024] S4, if the misfire occurs in the pre-combustion chamber, obtain the excess air coefficient value of the oxygen sensor, and close the fuel injector to make the excess air coefficient value of the oxygen sensor higher than the ignition excess air coefficient value of the main combustion chamber until the ignition condition is restored; Specifically, the step S4 includes step S41 to step S42: S41, judging that the state of the mixed gas in the pre-combustion chamber has been restored based on the thermocouple sensor in the shaft needle; S42, repeatedly determine the ignition temperature threshold, the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value according to the working state of the engine; obtain the instantaneous angular velocity value of the crankshaft based on the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value in combination with the speed sensor, and judge whether there is a misfire based on the angular velocity value; if so, judge whether there is ignition in the pre-combustion chamber based on the thermocouple on the pre-combustion chamber spark plug, and judge the location where the misfire occurs.

[0025] It needs to be explained that in the process of handling pre-combustion chamber misfire, after opening the pintle, when the excess air coefficient value is higher than the threshold value L1, it is judged that the state of the mixture in the pre-combustion chamber has been restored and the conditions for resuming ignition have been met.

[0026] In specific implementation, Figure 2 As shown, the engine has two groups of injection mechanisms, namely, the intake port injector 9 and the pre-combustion chamber injector 1. Most of the fuel is injected in the intake port 8 and enters the cylinder to form a mixed gas. A small amount of fuel is injected in the pre-combustion chamber 7. After a certain amount of fuel is injected in the pre-combustion chamber 7, it is ignited by the spark plug 2. Combustion is first formed in the pre-combustion chamber, and the flame is ejected from the pre-combustion chamber spray hole 5 to ignite the mixed gas in the main combustion chamber 11. At the same time, the solenoid valve 13 is in a closed state, the pre-combustion chamber pin 12 is close to the pin hole, and the pre-combustion chamber is in a closed state. When the pre-combustion chamber needs to be opened, the solenoid valve 13 is opened, the pin 12 moves upward, and the pre-combustion chamber 7 is in a connected state with the main combustion chamber 11.

[0027] like Figure 2 As shown, the thermocouple 14 is arranged through the center hole of the pin 12, and the measuring point of the thermocouple is in the sealing ball at the top of the pin 12. This ignition method has large ignition energy and can better realize the lean combustion of the engine. However, the pre-combustion chamber has a large wet wall area, the exhaust is not smooth, and there is a lot of residual exhaust gas. Therefore, once a misfire occurs in the pre-combustion chamber, if no measures are taken, the mixture in the pre-combustion chamber will be continuously enriched in the subsequent process, making it difficult to recover from the misfire. In addition, since the active pre-combustion chamber engine has two combustion chambers (main combustion chamber and pre-combustion chamber) and usually, the main combustion chamber contains a lean mixture, which requires a lot of ignition energy, and there is also a certain risk of misfire. After the engine misfires, it is necessary to determine in which combustion chamber the misfire occurs, and take different measures so that the engine can quickly return to normal working conditions.

[0028] In the specific implementation case, the engine is a 2.0L inline four-cylinder engine, under a certain speed and load (engine speed 1400rpm, torque 155N·m), the intake temperature is 27℃, the intake pressure is 1.1bar, and the coolant temperature is 92℃. The subsequent implementation plan is only for the current engine working condition. Under other working conditions, the specific adjustment parameters need to be determined according to the actual situation. During the engine calibration process, this method is used to identify and handle the engine misfire phenomenon. The specific implementation method is as follows: (1) Initial value setting: In this case, t1 is 550K, L1 is 4.2, and L2 is 2.7. The pre-chamber injection amount is 4.7% of the total injection amount.

[0029] (2)After the engine misfires, when the temperature t collected by the current thermocouple 14 is 464K (t < t1), it can be determined that misfiring has occurred in the prechamber.

[0030] (3)Open the pintle 12 and stop the fuel injection of the intake port injector 9 and the prechamber injector 1. In the next cycle, read the value of the excess air coefficient of the current cycle through the oxygen sensor corresponding to the cylinder. The value is 4.0, which is less than the threshold value of 2.2. Continue to open the pintle 12 in the next cycle and stop the fuel injection of the intake port injector 9 and the prechamber injector 1. At this time, the value of the excess air coefficient read is 4.7. Close the pintle 12 and resume the fuel injection of the intake port injector 9 and the prechamber injector 1.

[0031] (4)Make a judgment again, and the engine misfiring phenomenon disappears. The processing is completed. After the end, re-ignite and repeat steps S1 to S5.

[0032] Embodiment 2 The method for handling misfires of an engine with an openable and closable active prechamber in the second embodiment of the present invention is different from that of the first embodiment in that the method includes steps S01 to S05: S01, determine the ignition temperature threshold, the excess air coefficient value for prechamber ignition, and the excess air coefficient value for main combustion chamber ignition according to the working state of the engine; S02, based on the excess air coefficient value for prechamber ignition and the excess air coefficient value for main combustion chamber ignition, and combined with the rotational speed sensor, obtain the instantaneous angular velocity value of the crankshaft, and determine whether there is a misfiring phenomenon based on the angular velocity value; S03, if so, determine whether ignition occurs in the prechamber based on the thermocouple on the prechamber spark plug, and determine the location where the misfiring phenomenon occurs; S04, if the misfiring phenomenon occurs in the main combustion chamber, obtain the excess air coefficient value of the oxygen sensor, and increase the fuel injection pulse width of the intake port injector so that the excess air coefficient value of the oxygen sensor is lower than the excess air coefficient value for main combustion chamber ignition; Specifically, step S04 includes step S041: S041, enrich the air-fuel mixture in the main combustion chamber, determine that the air-fuel mixture concentration in the main combustion chamber reaches the condition for restoring ignition, and correct the fuel injection map of the engine; S05, repeatedly determining the ignition temperature threshold, the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value according to the working state of the engine; obtaining the crankshaft instantaneous angular velocity value based on the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value in combination with the speed sensor, and judging whether there is a misfire based on the angular velocity value; if so, judging whether there is ignition in the pre-combustion chamber based on the thermocouple on the spark plug of the pre-combustion chamber, and judging the location where the misfire occurs; It should be explained that when misfire occurs in the main combustion chamber, the mixture in the main combustion chamber is enriched so that the excess air coefficient value is lower than the threshold value L2, and it is determined that the concentration of the mixture in the main combustion chamber reaches the condition for resuming ignition, and the injection map of the engine is corrected. After completion, ignition is re-performed, and steps S01 to S05 are repeated.

[0033] In summary, the misfire handling method of the engine with an openable and closable active pre-combustion chamber in the above-mentioned embodiment of the present invention can determine whether a misfire occurs through the ignition excess air coefficient value of the pre-combustion chamber and the ignition excess air coefficient value of the main combustion chamber in combination with the speed sensor to obtain the instantaneous angular velocity value of the crankshaft, and determine the location of the misfire through the thermocouple, so as to determine the combustion chamber where the misfire occurs, achieve rapid recovery after the misfire, and reduce the impact on subsequent cycles. By making the excess air coefficient value of the oxygen sensor higher than the ignition excess air coefficient value of the main combustion chamber, damage to the engine due to misfire is avoided, thereby achieving stable operation of the engine, extending the service life of the engine, and also achieving automatic control of the stable operation of the engine.

[0034] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0035] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for handling misfires in an engine having an openable and closable active pre-combustion chamber, characterized in that: The method comprises: Determine the ignition temperature threshold, the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value according to the working state of the engine; Based on the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value and in combination with a speed sensor, an instantaneous angular velocity value of the crankshaft is obtained, and based on the angular velocity value, whether there is a misfire phenomenon is determined; If yes, determine whether there is ignition in the pre-combustion chamber based on the thermocouple on the pre-combustion chamber spark plug, and determine the location where the misfire occurs; If the misfire occurs in the pre-combustion chamber, the excess air coefficient value of the oxygen sensor is obtained, and the injector is closed so that the excess air coefficient value of the oxygen sensor is higher than the main combustion chamber ignition excess air coefficient value until the ignition condition is restored.

2. The misfire treatment method of an engine with an openable and closable active pre-combustion chamber according to claim 1, characterized in that: The basic parameters of the engine include cylinder diameter, stroke and compression ratio; The working state of the engine includes speed, load, intake air temperature, intake air pressure, coolant temperature and confirmation of initial value; The confirmed initial values ​​include an ignition temperature threshold, a pre-combustion chamber ignition excess air coefficient value, and a main combustion chamber ignition excess air coefficient value.

3. The misfire treatment method of an engine with an openable and closable active pre-combustion chamber according to claim 1, characterized in that: The step of determining whether ignition is ignited in the pre-combustion chamber based on the thermocouple on the pre-combustion chamber spark plug comprises: Measuring the ignition temperature of the pintle tip based on a thermocouple sensor, and judging whether there is a fire in the pre-combustion chamber according to the ignition temperature; If the ignition temperature is lower than the currently set threshold, it is determined that the pre-combustion chamber is misfiring.

4. The misfire treatment method of an engine with an openable and closable active pre-combustion chamber according to claim 1, characterized in that: After the step of determining the location where the misfire occurs, the method further comprises: If the misfire occurs in the main combustion chamber, the excess air coefficient value of the oxygen sensor is obtained, and the injection pulse width of the intake manifold injector is increased so that the excess air coefficient value of the oxygen sensor is lower than the ignition excess air coefficient value of the main combustion chamber.

5. The misfire treatment method of an engine with an openable and closable active pre-combustion chamber according to claim 4, characterized in that: After the step of making the excess air coefficient value of the oxygen sensor lower than the ignition excess air coefficient value of the main combustion chamber, the method further includes: Repeat the process of determining the ignition temperature threshold, the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value according to the working state of the engine; obtaining the instantaneous angular velocity value of the crankshaft based on the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value in combination with the speed sensor, and judging whether there is a misfire based on the angular velocity value; if so, judging whether there is ignition in the pre-combustion chamber based on the thermocouple on the pre-combustion chamber spark plug, and judging the location where the misfire occurs.

6. The misfire treatment method of an engine with an openable and closable active pre-combustion chamber according to claim 4, characterized in that: After the step of making the excess air coefficient value of the oxygen sensor lower than the ignition excess air coefficient value of the main combustion chamber, the method further includes: The mixture in the main combustion chamber is enriched, and it is determined whether the concentration of the mixture in the main combustion chamber reaches a condition for resuming ignition, and the fuel injection map of the engine is corrected.

7. The misfire treatment method of an engine with an openable and closable active pre-combustion chamber according to claim 1, characterized in that: After the step of making the excess air coefficient value of the oxygen sensor higher than the ignition excess air coefficient value of the main combustion chamber, the method further includes: judging that the state of the mixed gas in the pre-combustion chamber has been restored based on the thermocouple sensor in the shaft needle; Repeat the process of determining the ignition temperature threshold, the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value according to the working state of the engine; obtaining the instantaneous angular velocity value of the crankshaft based on the pre-combustion chamber ignition excess air coefficient value and the main combustion chamber ignition excess air coefficient value in combination with the speed sensor, and judging whether there is a misfire based on the angular velocity value; if so, judging whether there is ignition in the pre-combustion chamber based on the thermocouple on the pre-combustion chamber spark plug, and judging the location where the misfire occurs.

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