Engine device and method for controlling engine device

Abstract

The invention provides an engine device and a control method thereof. The engine device can more appropriately determine an abnormal combustion suppression method to suppress abnormal combustion and operate the engine device. An engine device (1) driven by gaseous fuel detects abnormal combustion occurring in a combustion chamber (12a) of an engine (2), monitors the frequency and intensity of occurrence of the abnormal combustion, and determines a suppression method for suppressing the abnormal combustion on the basis of the frequency and intensity of occurrence. As the suppression method, the engine device (1) controls at least one of the ignition timing of the gaseous fuel, the excess air ratio of intake air in a mixture of the gaseous fuel and intake air, and the cutoff of the gaseous fuel.

Description

Technical Field

[0001] The present invention relates to an engine device which is driven by injecting gas fuel into a combustion chamber and a control method thereof. Background Art

[0002] In the past, there have been engine devices that drive a gas engine by injecting a gas fuel such as hydrogen into a combustion chamber in a cylinder, and dual-fuel engines that drive the engine by injecting a gas fuel such as hydrogen and at least one of a liquid fuel such as light oil or heavy oil into a combustion chamber in a cylinder. For example, the dual-fuel engine operates in either a gas mode in which the engine is driven by injecting a gas fuel into the combustion chamber, or a diesel mode in which the engine is driven by injecting a liquid fuel into the combustion chamber. In addition, as another operation mode, the engine operates in a mixed combustion mode in which the engine is driven by injecting both a gas fuel and a liquid fuel into the combustion chamber. In such an engine device, abnormal combustion such as premature ignition (premature ignition) in which the gas fuel spontaneously ignites may occur in the combustion chamber before ignition by a micro-pilot method (Japanese: マイクロパイロット method) that injects a small amount of liquid fuel or ignition by an ignition device that uses a spark ignition method using a spark plug, and therefore it is required to suppress abnormal combustion.

[0003] For example, according to Patent Document 1, a control device for an internal combustion engine includes: an occurrence frequency detection mechanism for detecting the occurrence frequency of pre-ignition per unit time; and a temperature range variable mechanism for changing the range of the pre-ignition suppression temperature range in such a manner that the occurrence frequency of pre-ignition in at least a part of the pre-ignition suppression temperature range is below the allowable limit when the occurrence frequency of pre-ignition in at least a part of the pre-ignition suppression temperature range exceeds the allowable limit. Furthermore, the cylinder wall temperature control mechanism of the control device controls the pre-ignition suppression temperature range changed by the temperature range variable mechanism in such a manner that the wall temperature parameter converges to the pre-ignition suppression temperature range.

[0004] In addition, according to Patent Document 2, a method for controlling the combustion of a supercharged internal combustion engine in which ignition is controlled comprises: a step (a) of selecting a physical model representing the progression of pressure in a cylinder within a combustion range accompanied by a premature ignition phenomenon as a function of the rotation angle of the crankshaft; a step (b) of predicting the cylinder pressure based on the physical model and a measured value of the intake pressure; a step (c) of detecting the start of abnormal combustion by comparing at least one first value of a variable calculated using the measured value of the cylinder pressure with at least one second value of a variable calculated using the predicted value of the cylinder pressure; a step of characterizing the magnitude of the premature ignition by repeating steps (b) and (c) at a number of determined crankshaft angles; and a step of controlling the progression of the abnormal combustion detected in the combustion chamber according to the magnitude of the premature ignition phenomenon.

[0005] In addition, according to patent document 3, a combustion device of an internal combustion engine including a fuel injection valve for injecting and supplying gaseous fuel into a combustion chamber, and a spark plug for igniting the gaseous fuel injected and supplied by the fuel injection valve is provided with a fuel injection valve at a position where the injected and supplied gaseous fuel is gathered around the spark plug, and the internal combustion engine can be driven by liquid fuel in addition to gaseous fuel, wherein the combustion device is further provided with a fuel switching mechanism for switching the fuel of the internal combustion engine according to the operating state of the internal combustion engine, and when pre-ignition occurs in the internal combustion engine, the fuel switching mechanism switches the fuel and drives the internal combustion engine only by liquid fuel.

[0006] Patent Document 1: Japanese Patent No. 5939263

[0007] Patent Document 2: Japanese Patent No. 5405950

[0008] Patent Document 3: Japanese Patent No. 4075165

[0009] In the prior art such as that described in the above-mentioned Patent Document 1, the pre-ignition suppression control is determined only by evaluating the frequency of occurrence of pre-ignition. Therefore, in the case of a low frequency of occurrence, even if an abnormal combustion occurs in which the internal pressure of the combustion chamber (cylinder pressure) increases significantly, the abnormal combustion suppression control cannot be performed, and the engine (internal combustion engine) may be damaged due to exceeding the allowable cylinder pressure.

[0010] On the other hand, in the prior art such as that described in the above-mentioned Patent Document 2, the abnormal combustion suppression control is judged only by evaluating the increase in the internal pressure of the combustion chamber (cylinder pressure). Therefore, when the increase in the cylinder pressure is small, even if abnormal combustion with a high frequency of pre-ignition occurs, the abnormal combustion suppression control cannot be performed.

[0011] As described above, in the prior art, only limited suppression methods are provided for abnormal combustion such as pre-ignition that occurs due to various reasons. Therefore, if the cause of abnormal combustion and the suppression method are not combined properly, the abnormal combustion cannot be suppressed.

[0012] In addition, in the prior art such as that described in the above-mentioned Patent Document 3, the operating time under the gas fuel (hydrogen, ammonia, etc.) expected to reduce CO2 (carbon dioxide) is limited, so the reduction effect of greenhouse gases is limited and the commercial value of the engine device is reduced. Summary of the invention

[0013] An object of the present invention is to provide an engine device and a control method thereof that can more appropriately determine a method for suppressing abnormal combustion to operate an engine device while suppressing abnormal combustion.

[0014] In order to solve the above-mentioned problems, the engine device of the present invention is an engine device driven by gas fuel, characterized in that abnormal combustion occurring in a combustion chamber is detected, and the frequency and intensity of occurrence of the abnormal combustion are monitored, and a suppression method for suppressing the above-mentioned abnormal combustion is determined based on the above-mentioned frequency and intensity.

[0015] Alternatively, the engine device of the present invention is an engine device driven by at least one of gas fuel and liquid fuel, and is characterized in that when driven by the above-mentioned gas fuel, abnormal combustion occurring in the combustion chamber is detected, and the frequency and intensity of the abnormal combustion are monitored, and a suppression method for suppressing the above-mentioned abnormal combustion is determined based on the above-mentioned frequency and the above-mentioned intensity. As the above-mentioned suppression method, the ignition timing of the above-mentioned gas fuel, the excess air ratio of the above-mentioned intake air in the mixture composed of the above-mentioned gas fuel and the intake air, the cut-off of the above-mentioned gas fuel, and at least one of switching to driving by both the above-mentioned gas fuel and the above-mentioned liquid fuel or driving only by the above-mentioned liquid fuel are controlled.

[0016] In addition, in order to solve the above-mentioned problems, the control method of the engine device of the present invention is a control method of an engine device driven by gas fuel, characterized in that abnormal combustion occurring in a combustion chamber is detected, and the frequency and intensity of occurrence of the abnormal combustion are monitored, and a suppression method for suppressing the above-mentioned abnormal combustion is determined based on the above-mentioned frequency and the above-mentioned intensity.

[0017] According to the present invention, it is possible to provide an engine device and a control method thereof that can more appropriately determine a method for suppressing abnormal combustion and operate while suppressing abnormal combustion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a left side view showing the engine device according to the embodiment of the present invention.

[0019] Figure 2 This is a graph showing an example of an operable region in the relationship between the ignition timing and the excess air ratio in the engine device.

[0020] Figure 3 This is a graph showing an example of the distribution of the frequency of occurrence of abnormal combustion corresponding to the operable region in the relationship between the ignition timing and the excess air ratio in the engine device according to the embodiment of the present invention.

[0021] Figure 4 This is a graph showing an example of the distribution of the intensity of occurrence of abnormal combustion corresponding to the operable region in the relationship between the ignition timing and the excess air ratio in the engine device according to the embodiment of the present invention.

[0022] Figure 5This is a matrix diagram showing an example of a method of suppressing abnormal combustion according to the occurrence frequency and occurrence intensity of abnormal combustion in the engine device according to the embodiment of the present invention.

[0023] Description of Reference Numerals

[0024] 1…engine device; 2…engine; 3…intake passage; 4…exhaust passage; 5…control unit; 6…gas fuel injection unit; 7…throttle valve; 8…ignition device; 11…cylinder body; 12…cylinder; 12a…combustion chamber; 13…cylinder; 14…piston; 15…cylinder head; 16…connecting rod; 17…crankshaft; 18…angle sensor; 19…pressure sensor; 20…air-fuel ratio sensor; 22…intake port; 23…exhaust port; 24…intake valve; 25…exhaust valve. DETAILED DESCRIPTION

[0025] An engine device 1 according to an embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 As shown, the engine device 1 includes an engine 2 , an intake passage 3 , an exhaust passage 4 , and a control unit 5 .

[0026] In particular, in the present embodiment, the engine device 1 is a gas engine that is configured to be driven by injecting a gas fuel such as hydrogen into a combustion chamber 12a of the engine 2, and includes a gas fuel injection unit 6 for injecting the gas fuel, a throttle valve 7 for adjusting the amount of intake air, and an ignition device 8 for igniting the gas fuel in the combustion chamber 12a.

[0027] The engine 2 is configured by including a plurality of cylinders 12 in a cylinder block 11. Figure 1 Only one cylinder 12 is shown in the figure. Figure 1 As shown, each cylinder 12 is composed of a cylinder 13, a piston 14 and a cylinder head 15. Each cylinder 12 is provided with a gas fuel injection unit 6 and an ignition device 8.

[0028] The cylinder 13 is formed in a cylindrical shape, for example, in the cylinder body 11, and the piston 14 is slidably accommodated in the cylinder 13. The cylinder head 15 is attached to the upper side of the cylinder 13, and the cylinder 13 and the cylinder head 15 form a combustion chamber 12a inside.

[0029] A crankshaft 17 is connected to the piston 14 below the cylinder 13 via a connecting rod 16 , and the reciprocating motion of the piston 14 is converted into the rotational motion of the crankshaft 17 via the connecting rod 16 .

[0030] The cylinder 13 is provided with an angle sensor 18 for detecting the rotation angle of the crankshaft 17, that is, the rotation speed of the engine 2, and the angle sensor 18 sends the detection result to the control unit 5. The cylinder 13 is provided with a pressure sensor 19 for detecting the internal pressure of the combustion chamber 12a, that is, the cylinder pressure of the cylinder 13, and the pressure sensor 19 sends the detection result to the control unit 5.

[0031] The cylinder head 15 has an intake port 22 and an exhaust port 23 communicating with the combustion chamber 12a of the cylinder 13, and includes an intake valve 24 and an exhaust valve 25 that respectively open and close the intake port 22 and the exhaust port 23 with respect to the combustion chamber 12a.

[0032] The intake port 22 is connected to the intake passage 3, and the air supplied from the intake passage 3 is introduced into the combustion chamber 12a. The exhaust port 23 is connected to the exhaust passage 4, and the exhaust gas generated in the combustion chamber 12a is discharged into the exhaust passage 4. By opening the intake valve 24, the mixed gas of fuel gas and air can be sucked into the combustion chamber 12a through the intake port 22, and on the other hand, by opening the exhaust valve 25, the exhaust gas generated in the combustion chamber 12a can be discharged through the exhaust port 23.

[0033] also, Figure 1 , the intake passage 3 and the intake port 22 are directly connected. However, in order to connect the intake passage 3 and the intake ports 22 of the plurality of cylinders 12, an intake manifold having a branch flow path branching from the intake passage 3 to the plurality of cylinders 12 may be provided between the intake passage 3 and the engine 2. Figure 1 The figure shows an example in which the exhaust passage 4 and the exhaust port 23 are directly connected, but when the exhaust passage 4 and the exhaust ports 23 of multiple cylinders 12 are connected, an exhaust manifold having a branch flow path branching from the exhaust passage 4 to the multiple cylinders 12 can be provided between the exhaust passage 4 and the engine 2.

[0034] In each cylinder 12, a gas fuel injection unit 6 is provided at an intake port 22, and is controlled by a control unit 5 to inject gas fuel supplied from a gas fuel tank (not shown) into the intake port 22. A mixed gas of air supplied from the intake passage 3 and gas fuel supplied from a gas fuel tank (not shown) is supplied from the intake port 22 to the combustion chamber 12a. The gas fuel injection unit 6 is composed of, for example, a gas intake valve, a gas injector, etc. The gas fuel injection unit 6 is controlled by the control unit 5 in terms of injection pressure, injection timing, etc. of the gas fuel.

[0035] In each cylinder 12, an ignition device 8 is provided in the cylinder head 15. The ignition device 8 is, for example, a micro-pilot type device that injects a small amount of liquid fuel, and is composed of an injector or the like that injects liquid fuel supplied from a liquid fuel tank (not shown) into a combustion chamber 12a below the cylinder head 15. The ignition device 8 is controlled by the control unit 5 to control the injection pressure and injection timing of the liquid fuel. Alternatively, the ignition device 8 may be composed of a spark ignition type device using a spark plug.

[0036] The intake passage 3 is connected to the intake port 22 of the cylinder 12 of the engine 2, and compressed and cooled air is supplied to each cylinder 12 through the intake port 22. In addition, a supercharger (not shown) that compresses the air flowing through the intake passage 3 and sends it to the downstream side in the intake direction, and an intercooler (not shown) that cools the air flowing through the intake passage 3 can be provided in the intake passage 3. In addition, an air filter (not shown) that purifies and introduces fresh air can be provided at the upstream end of the intake passage 3 in the intake direction.

[0037] The intake passage 3 is provided with a throttle valve 7 for adjusting the amount of intake air delivered to the intake port 22. The throttle valve 7 is controlled and the opening is adjusted by the control unit 5. The amount of intake air delivered to the intake port 22 is adjusted according to the opening of the throttle valve 7, thereby adjusting the excess air ratio (the proportion of intake air in the mixture) of the gas fuel and air injected into the combustion chamber 12a from the intake port 22. That is, by adjusting the opening of the throttle valve 7, the flow rate of air supplied from the intake passage 3 to the intake port 22 can be adjusted.

[0038] The exhaust passage 4 is connected to the exhaust port 23 of each cylinder 12 of the engine 2, and exhaust gas generated in each cylinder 12 is discharged through the exhaust port 23. An air-fuel ratio sensor 20 is provided in the exhaust passage 4 to detect the air-fuel ratio of the exhaust gas. The air-fuel ratio sensor 20 sends the detection result to the control unit 5.

[0039] The control unit 5 is a computer such as an ECU (Engine Control Unit) that controls the operation of the engine 2, and includes a CPU, ROM, RAM, etc., and is configured to control various parts of the engine 2. The control unit 5 can store various programs for controlling the engine 2, and control the engine 2 by reading and executing the programs.

[0040] In the engine device 1, the ignition device 8 is usually operated at the ignition timing determined by the control unit 5, for example, by injecting liquid fuel into the combustion chamber 12a at a predetermined liquid fuel injection timing (injection timing), so that the gas fuel inside the combustion chamber 12a is ignited and combustion starts. However, when an abnormality such as excessively high temperature or excessively high pressure inside the combustion chamber 12a occurs, the gas fuel inside the combustion chamber 12a may spontaneously ignite before the ignition timing (liquid fuel injection timing), and abnormal combustion such as pre-ignition (premature ignition) may occur.

[0041] When the engine device 1 is operated, the relationship between the ignition timing (liquid fuel injection timing) of the combustion chamber 12a and the excess air ratio (ratio of intake air to fuel in the mixture) of the mixture injected into the combustion chamber 12a is as follows: Figure 2As shown, the engine device 1 can be operated within the operable region 30 , but outside the operable region 30 , there is a high possibility that dangerous combustion will occur in the combustion chamber 12 a , and the engine device 1 cannot be operated.

[0042] In addition, near the edge of the operable region 30, there is a high possibility that abnormal combustion such as pre-ignition (premature ignition) will occur in the engine 2 even within the range of the operable region 30. For example, near the first edge 31 on the side where the excess air ratio is relatively high in the operable region 30, there is a high possibility that pre-ignition and backfire will occur as abnormal combustion, and near the second edge 32 on the side where the excess air ratio is relatively low, there is a high possibility that pre-ignition and knocking will occur as abnormal combustion.

[0043] in addition, Figure 3 2 shows the result of monitoring the frequency of abnormal combustion that occurs when the engine device 1 is operated within the operable region 30 . The frequency of abnormal combustion increases near the first edge 31 and the second edge 32 of the operable region 30 . Figure 4 2 shows the result of monitoring the occurrence intensity of abnormal combustion that occurs when the engine device 1 is operated within the operable region 30 . The occurrence intensity of abnormal combustion increases near the first edge 31 and the second edge 32 of the operable region 30 .

[0044] However, the distribution of the frequency of abnormal combustion and the distribution of the intensity of abnormal combustion are different in the operable region 30. Therefore, when abnormal combustion of the engine 2 is detected, it is difficult to determine which abnormal combustion has occurred, and it is difficult to appropriately determine a suppression method for suppressing abnormal combustion, even if the excess air ratio and the ignition timing are referred to. In addition, it is difficult to determine which abnormal combustion has occurred, and it is difficult to appropriately determine a suppression method for suppressing abnormal combustion, even if only the frequency of abnormal combustion or the intensity of abnormal combustion is referred to.

[0045] Therefore, in the present invention, the control unit 5 detects abnormal combustion occurring in the combustion chamber 12a, monitors the occurrence frequency and occurrence intensity of the abnormal combustion, and determines a suppression method for suppressing the abnormal combustion based on the occurrence frequency and occurrence intensity.

[0046] Specifically, first, after the engine device 1 starts to operate, the control unit 5 detects abnormal combustion occurring in the engine 2. For example, the control unit 5 detects the cylinder pressure of the cylinder 13 through the pressure sensor 19 and monitors the ignition timing (liquid fuel injection timing) of the ignition device 8. When the cylinder pressure exceeds a predetermined cylinder pressure threshold before the ignition timing, it is determined that pre-ignition has occurred.

[0047] In addition, the control unit 5 detects the rotation angle of the crankshaft 17 through the angle sensor 18, and calculates the rotation speed of the engine 2 based on the rotation angle. The control unit 5 calculates the frequency of abnormal combustion by the ratio of the cycles determined as pre-ignition (premature ignition) in a plurality of cycles based on the rotation speed of the engine 2 within a predetermined period and the number of abnormal combustions that occurred within the predetermined period.

[0048] In addition, the control unit 5 detects the internal pressure of the combustion chamber 12a caused by the pre-ignition (premature ignition), that is, the increase range of the cylinder pressure of the cylinder 13 as the occurrence intensity of abnormal combustion (premature ignition intensity). For example, the control unit 5 detects the maximum cylinder pressure of the cylinder 13 through the pressure sensor 19 when the engine 2 is normally running, and obtains the mode of the maximum cylinder pressure during normal combustion based on the result. In addition, the control unit 5 detects the maximum cylinder pressure of the cylinder 13 through the pressure sensor 19 when the pre-ignition occurs in the engine 2, and obtains the maximum cylinder pressure during premature ignition. Then, as shown in the following formula (1), the control unit 5 calculates the occurrence intensity Int of abnormal combustion based on the difference average value between the maximum cylinder pressure Pmax1 during premature ignition and the mode Pmax2 of the maximum cylinder pressure during normal combustion. In the formula (1), n ​​represents the number of premature ignition cycles, and Pmax1(k) represents the maximum cylinder pressure during premature ignition in the kth cycle.

[0049] Equation 1

[0050]

[0051] The control unit 5 performs condition determination such as a matrix and a flowchart based on the frequency and intensity of abnormal combustion detected as described above, and determines a suppression method for suppressing abnormal combustion. The control unit 5 preferably stores a program for condition determination of the frequency and intensity of abnormal combustion, and determines the suppression method by reading and executing the program.

[0052] Figure 5, a selection matrix of suppression methods corresponding to the relationship between the occurrence frequency and the occurrence intensity of abnormal combustion is shown in FIG. According to the condition judgment of the selection matrix, the control unit 5 controls in a manner of enriching the gas fuel and advancing the ignition timing (liquid fuel injection timing) when the occurrence frequency of abnormal combustion is high frequency and the occurrence intensity is high intensity. At this time, the control unit 5 preferably determines whether it is high frequency or low frequency by comparing the occurrence frequency of abnormal combustion with a predetermined frequency threshold, and determines whether it is high intensity or low intensity by comparing the occurrence intensity of abnormal combustion with a predetermined intensity threshold. In addition, the frequency threshold and the intensity threshold are preferably prepared according to the model and environment of the engine device 1. The control unit 5 preferably controls at least one of the ignition timing of the gas fuel and the excess air ratio of the intake air in the mixture composed of the gas fuel and the intake air. For example, the control unit 5 controls in a manner of advancing the ignition timing by controlling the ignition device 8, and controls in a manner of reducing the excess air ratio and enriching the gas fuel by controlling the gas fuel injection unit 6 and the throttle valve 7.

[0053] In addition, the control unit 5 performs control in a manner that makes the gas fuel leaner when the frequency of occurrence of abnormal combustion is low and the intensity of occurrence is high in the second region 42. At this time, the control unit 5 preferably controls at least one of the excess air ratio of the intake air in the mixed gas composed of the gas fuel and the intake air and the cutoff of the gas fuel. For example, the control unit 5 controls the gas fuel injection unit 6 and the throttle valve 7 so that the excess air ratio is reduced and the gas fuel is leaner.

[0054] In addition, when the control unit 5 is in the third region 43 where the frequency of occurrence of abnormal combustion is low and the intensity of occurrence is low, the operation of the engine 2 is in a safe state, so it is determined that it is not necessary to suppress abnormal combustion. In addition, when the control unit 5 exceeds the first region 41 and the second region 42 and is in the fourth region 44 where the frequency of occurrence of abnormal combustion is high and the intensity of occurrence is high, the operation of the engine 2 is in an inoperable state exceeding the operable region 30, so it is also possible not to suppress abnormal combustion and, for example, stop the driving of the engine 2.

[0055] As described above, according to the present embodiment, the engine device 1 driven by injecting gas fuel into the combustion chamber 12a of the engine 2 detects abnormal combustion occurring in the combustion chamber 12a, and monitors the frequency and intensity of the abnormal combustion, and determines and executes a suppression method for suppressing the abnormal combustion based on the frequency and intensity of the abnormal combustion.

[0056] In other words, the control method of the engine device 1 driven by injecting gas fuel into the combustion chamber 12a of the engine 2 is to detect abnormal combustion occurring in the combustion chamber 12a, monitor the frequency and intensity of occurrence of the abnormal combustion, and determine and execute a suppression method for suppressing abnormal combustion based on the frequency and intensity of occurrence. In addition, the control method can be executed by the control unit 5, for example, it can be composed of a program.

[0057] In the engine device 1, when abnormal combustion is judged only by the frequency of occurrence, even if the intensity of abnormal combustion is extremely large, it will be ignored if the frequency of occurrence is small. In addition, in the engine device 1, when abnormal combustion is judged only by the intensity of occurrence, even if the frequency of abnormal combustion is extremely large, it will be ignored if the intensity of occurrence is small. In either case, there is a risk of causing extremely deep damage to the engine 2 due to the ignored abnormal combustion. In addition, there are various combinations of the frequency of occurrence of abnormal combustion and the intensity of occurrence, and the best suppression method for abnormal combustion also varies according to the combination of the frequency of occurrence and the intensity of occurrence.

[0058] In contrast, the engine device 1 of the present embodiment can more appropriately determine a method for suppressing abnormal combustion by simultaneously referring to both the occurrence frequency and the occurrence intensity of abnormal combustion. The suppression method can more appropriately suppress abnormal combustion and operate the engine 2 more safely.

[0059] According to the present embodiment, as a suppression method, the engine device 1 controls at least one of the ignition timing of the gas fuel, the excess air ratio of the intake air in the mixture composed of the gas fuel and the intake air, and the cutoff of the gas fuel.

[0060] Thus, the engine device 1 can specifically determine a method for suppressing abnormal combustion according to the frequency and intensity of occurrence of abnormal combustion, and can optimally select a method for suppressing abnormal combustion to use alone or in combination.

[0061] Furthermore, according to the present embodiment, the engine device 1 determines the suppression method based on condition determination such as a matrix or a flowchart showing the relationship between the occurrence frequency and occurrence intensity of abnormal combustion and the suppression method of abnormal combustion.

[0062] Thus, the engine device 1 can make the determination and control of the suppression method of abnormality determination easy and understandable by using condition determination such as a matrix and a flowchart. In addition, the control data input to the control unit 5 can be simplified and processed easily.

[0063] Furthermore, according to the present embodiment, the engine device 1 determines the method of suppressing abnormal combustion based on the comparison between the frequency of occurrence of abnormal combustion and a predetermined frequency threshold value and the comparison between the intensity of occurrence of abnormal combustion and a predetermined intensity threshold value.

[0064] Thus, the engine device 1 can clearly recognize and determine the state of the occurrence frequency and occurrence intensity of abnormal combustion, and can select a method of suppressing abnormal combustion that is more suitable for the state of the occurrence frequency and occurrence intensity of abnormal combustion.

[0065] In addition, in the above embodiment, the following example is described, that is, in the engine device 1, the control unit 5 determines whether the frequency and intensity of abnormal combustion are low or high, and determines whether the intensity is low or high, but the present invention is not limited to this example.

[0066] In another example, the control unit 5 may also determine the frequency and intensity of abnormal combustion respectively according to three or more levels, and determine the method of suppressing abnormal combustion based on the determination result. In addition, when controlling the ignition timing of the gas fuel and the excess air ratio of the intake air as the method of suppressing abnormal combustion, the control unit 5 may determine the control amount of the ignition timing and the excess air ratio according to the level of the frequency and intensity of abnormal combustion. Alternatively, in another example, the control unit 5 may also use a formula to calculate the control amount of the ignition timing and the excess air ratio based on the frequency and intensity of abnormal combustion.

[0067] In addition, in the above-mentioned embodiment, the following example is described, that is, the engine device 1 is a gas engine configured to be driven by injecting a gas fuel such as hydrogen into the combustion chamber 12a of the engine 2, but the present invention is not limited to this example. In another example, the engine device 1 can also be configured as a dual-fuel engine that is driven by injecting a gas fuel such as hydrogen and a liquid fuel such as light oil or heavy oil into the combustion chamber 12a of the engine 2. In this case, the engine device 1 injects gas fuel through the gas fuel injection unit 6 and injects liquid fuel through a liquid fuel injection unit such as a micro-pilot ignition device 8.

[0068] The engine device 1 of the dual-fuel engine operates in either a gas mode in which gas fuel is introduced into the combustion chamber 12a for driving, or a diesel mode in which liquid fuel is introduced into the combustion chamber 12a for driving. In addition, as another operating mode, it operates in a mixed combustion mode in which both gas fuel and liquid fuel are introduced into the combustion chamber 12a for driving.

[0069] In the engine device 1 of the dual-fuel engine, as a method of suppressing abnormal combustion determined according to the frequency and intensity of abnormal combustion, the control unit 5 controls the ignition timing of the gas fuel, the excess air ratio of the mixture, the cutoff of the gas fuel, and at least one of the switching to driving by both gas fuel and liquid fuel (mixed combustion mode) or driving only by liquid fuel (diesel mode).

[0070] The present invention can be modified appropriately within the scope of the gist or concept of the invention that can be read from the claims and the entire specification, and the engine device and control method thereof accompanying such modification are also included in the technical concept of the present invention.

[0071] [Notes on the invention]

[0072] The following is a summary of the invention extracted from the above-mentioned embodiment. In addition, each structure and each processing function described in the following notes can be selected and combined arbitrarily.

[0073] <Note 1>

[0074] An engine device is an engine device driven by gas fuel, characterized in that:

[0075] Detect abnormal combustion occurring in the combustion chamber and monitor the frequency and intensity of the abnormal combustion.

[0076] A suppression method for suppressing the abnormal combustion is determined based on the occurrence frequency and the occurrence intensity.

[0077] <Note 2>

[0078] The engine device according to note 1, characterized in that:

[0079] As the suppression method, at least one of an ignition timing of the gas fuel, an excess air ratio of the intake air in a mixture composed of the gas fuel and intake air, and a cutoff of the gas fuel is controlled.

[0080] <Note 3>

[0081] The engine device according to Note 1 or 2, characterized in that:

[0082] The suppression method is determined based on the condition determination indicating the relationship between the occurrence frequency and the occurrence intensity and the suppression method.

[0083] <Note 4>

[0084] The engine device according to any one of appendixes 1 to 3, characterized in that:

[0085] The suppression method is determined based on the frequency threshold of the occurrence frequency and the intensity threshold of the occurrence intensity.

[0086] <Note 5>

[0087] An engine device is an engine device driven by at least one of gas fuel and liquid fuel, characterized in that:

[0088] When driven by the gas fuel, abnormal combustion occurring in the combustion chamber is detected, and the frequency and intensity of the abnormal combustion are monitored.

[0089] A suppression method for suppressing the abnormal combustion is determined based on the occurrence frequency and the occurrence intensity.

[0090] As the above-mentioned suppression method, at least one of controlling the ignition timing of the above-mentioned gas fuel, the excess air ratio of the above-mentioned intake air in the mixture composed of the above-mentioned gas fuel and the intake air, the cutoff of the above-mentioned gas fuel, and the switching to the driving by both the above-mentioned gas fuel and the above-mentioned liquid fuel or the driving by only the above-mentioned liquid fuel is controlled.

[0091] <Note 6>

[0092] The engine device according to note 5, characterized in that:

[0093] The suppression method is determined based on the condition determination indicating the relationship between the occurrence frequency and the occurrence intensity and the suppression method.

[0094] <Note 7>

[0095] The engine device according to note 5 or 6, characterized in that:

[0096] The suppression method is determined based on the frequency threshold of the occurrence frequency and the intensity threshold of the occurrence intensity.

[0097] <Note 8>

[0098] A control method for an engine device is a control method for an engine device driven by gas fuel, characterized in that:

[0099] Detect abnormal combustion occurring in the combustion chamber and monitor the frequency and intensity of the abnormal combustion.

[0100] A suppression method for suppressing the abnormal combustion is determined based on the occurrence frequency and the occurrence intensity.

[0101] <Note 9>

[0102] The control method of the engine device according to Appendix 8 is characterized in that:

[0103] As the suppression method, at least one of an ignition timing of the gas fuel, an excess air ratio of the intake air in a mixture composed of the gas fuel and intake air, and a cutoff of the gas fuel is controlled.

[0104] <Note 10>

[0105] The control method of the engine device according to Note 8 or 9 is characterized in that:

[0106] The suppression method is determined based on the condition determination indicating the relationship between the occurrence frequency and the occurrence intensity and the suppression method.

[0107] <Note 11>

[0108] The control method of an engine device according to any one of appendixes 8 to 10, characterized in that:

[0109] The suppression method is determined based on the frequency threshold of the occurrence frequency and the intensity threshold of the occurrence intensity.

Claims

1. An engine device is an engine device driven by gas fuel, characterized in that: Detect abnormal combustion occurring in the combustion chamber and monitor the frequency and intensity of the abnormal combustion. A suppression method for suppressing the abnormal combustion is determined based on the occurrence frequency and the occurrence intensity.

2. The engine device according to claim 1, characterized in that: As the suppression method, at least one of an ignition timing of the gas fuel, an excess air ratio of the intake air in a mixture composed of the gas fuel and intake air, and a cutoff of the gas fuel is controlled.

3. The engine device according to claim 1, characterized in that: The suppression method is determined based on a condition determination showing a relationship between the occurrence frequency and the occurrence intensity and the suppression method.

4. The engine device according to claim 1, characterized in that: The suppression method is determined based on the frequency threshold of the occurrence frequency and the intensity threshold of the occurrence intensity.

5. An engine device driven by at least one of gas fuel and liquid fuel, characterized in that: When driven by the gas fuel, abnormal combustion occurring in the combustion chamber is detected, and the frequency and intensity of occurrence of the abnormal combustion are monitored. determining a suppression method for suppressing the abnormal combustion according to the occurrence frequency and the occurrence intensity, As the suppression method, at least one of controlling the ignition timing of the gas fuel, the excess air ratio of the intake air in the mixture composed of the gas fuel and the intake air, the cutoff of the gas fuel, and the switching to driving by both the gas fuel and the liquid fuel or driving by only the liquid fuel is controlled.

6. A method for controlling an engine device driven by gas fuel, characterized in that: Detect abnormal combustion occurring in the combustion chamber and monitor the frequency and intensity of the abnormal combustion. A suppression method for suppressing the abnormal combustion is determined based on the occurrence frequency and the occurrence intensity.

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