Electronic control device for hydrogen co-firing and power generation system using same

Abstract

To provide a hydrogen-mixed combustion electronic control device which can perform a combustion abnormal determination of a hydrogen-mixed combustion engine for each cylinder in realtime.SOLUTION: A hydrogen-mixed combustion electronic control device for controlling a mixing ratio of hydrogen which is mixedly combusted in a combustion chamber of a hydrogen-mixed combustion engine having a first fuel supply device for supplying first fuel to an engine and a second fuel supply device for supplying fuel partially containing hydrogen to the engine as second fuel, comprises: a crank angle sensor for detecting a rotation time of a crankshaft of the engine; and a calculation part for calculating an extreme value of the rotation time of the crankshaft and extreme value timing, on the basis of a detection result of the crank angle sensor. The control device determines a combustion state of the engine on the basis of the extreme value and the extreme value timing.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electronic control device for hydrogen co-fuel combustion and a power generation system using the same. [Background technology]

[0002] As a decarbonization system to reduce the use of fossil fuels, hydrogen co-firing engine systems that utilize hydrogen produced from renewable energy sources are being considered for power generation, cogeneration, etc. Because hydrogen has a combustion speed approximately seven times faster than conventional hydrocarbon fuels, it is possible to improve thermal efficiency by adjusting the supply of hydrogen.

[0003] On the other hand, the combustion timing changes significantly depending on the amount of hydrogen supplied, which can lead to abnormal combustion such as backfire, afterfire, pre-ignition, and knocking, and in some cases, engine failure. In addition, if hydrogen is outside of its flammable range, unburned hydrogen that does not burn completely will be discharged outside the engine, leading to a decrease in thermal efficiency. In that case, the discharge of hydrogen outside the engine will raise safety concerns in the surrounding area.

[0004] For these reasons, in an engine that uses hydrogen as a fuel in part, it is necessary to detect the combustion state in real time in order to suppress abnormal combustion and misfires. Technologies for detecting the combustion state are disclosed in Patent Documents 1 and 2.

[0005] Patent Document 1 describes that in an engine that uses hydrogen as part of its fuel, "the internal combustion engine control device detects the presence or absence of pre-ignition / backfire in each cylinder based on the internal pressure and crank angle of each cylinder, and performs control to increase the combustion speed for each cylinder in which pre-ignition is detected, and performs control to lower the internal cylinder temperature for each cylinder in which backfire is detected."

[0006] Patent Document 2 describes a method for detecting the extreme value timing of an existing crank rotation speed and estimating combustion timing without using an in-cylinder pressure sensor. For example, it describes that "the internal combustion engine includes a rotation speed calculation unit that calculates the crank rotation speed of an internal combustion engine, an extreme value timing calculation unit that calculates the extreme value timing of the crank rotation speed calculated by the rotation speed calculation unit, and a combustion state estimation unit that estimates a combustion state based on the extreme value timing of the crank speed calculated by the extreme value timing calculation unit." [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2016-130473 A [Patent Document 2] JP 2020-190234 A Summary of the Invention [Problem to be solved by the invention]

[0008] The method described in Patent Document 1 requires an internal cylinder pressure sensor for each cylinder, which entails additional costs, and also requires securing space and processing for connecting the internal cylinder pressure sensor to the combustion chamber. The method described in Patent Document 2 is capable of detecting the MFB50 timing (combustion center timing), but it is difficult to detect abnormal combustion such as knocking or pre-ignition in real time. In addition, because all cylinders are connected to the crankshaft, there is a problem in that it is difficult to determine the MFB50 timing for each cylinder. The present invention has been made in consideration of the above circumstances, and aims to provide an electronic control device for hydrogen-mixed combustion engines that can determine combustion abnormalities in each cylinder in real time without adding an in-cylinder pressure sensor or the like, and a power generation system using the same. [Means for solving the problem]

[0009] The electronic control device for hydrogen co-fuel combustion according to the present invention controls the first fuel to be fed to the engine. Directly into the combustion chamber a first fuel supply device for supplying the first fuel; Hydrogen-rich gas A hydrogen-mixed combustion electronic control device controls the mixture ratio of hydrogen mixed in the combustion chamber of the hydrogen-mixed combustion engine having a second fuel supply device that supplies the second fuel to the engine, and the second fuel supply device supplies the second fuel to the engine. angular velocity A crank angle sensor detects the crankshaft position based on the detection result of the crank angle sensor. Timing and extreme values ​​of angular velocity with respect to crank angle A calculation unit that calculates Extremes timing and extremes Based on this, the engine combustion state The hydrogen mixing ratio is adjusted based on the extreme value timing and the extreme value. Effect of the Invention

[0010] According to the present invention, it is possible to provide an electronic control device for a hydrogen-mixed combustion engine that can perform combustion abnormality determination for each cylinder in real time without adding an internal cylinder pressure sensor or the like, and a power generation system using the same. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a partially hydrogen fueled engine system. [Diagram 2] FIG. 1 is a diagram showing a 100-cycle average of the engine combustion pressure waveform. [Diagram 3] FIG. 4 is a diagram showing an example of a combustion pressure waveform for each cycle. [Figure 4] FIG. 2 is a diagram showing an example of the arrangement of cylinders, a crankshaft, a camshaft, and a controller. [Diagram 5] 2 is a block diagram showing an example of the internal configuration of a hydrogen-mixed combustion electronic control device 12. FIG. [Figure 6] FIG. 13 is a diagram showing an example of an electromagnetic pickup signal in a system using an electromagnetic pickup. [Figure 7] FIG. 1 is a diagram showing an example of a rotation time profile in the case of a four-cylinder engine. [Figure 8]FIG. 4 is a diagram showing a control flow of an electronic control device for hydrogen co-fuel combustion. [Figure 9] FIG. 11 is a diagram illustrating a combustion abnormality determination using extreme values ​​and extreme value timing. [Figure 10] FIG. 13 is a diagram showing the correlation between extreme timing and the center of gravity of combustion. [Figure 11] FIG. 11A is a diagram showing plot points for each cycle during normal combustion, and FIG. 11B is a diagram showing plot points for each cycle during abnormal combustion. [Figure 12] FIG. 2 is a diagram showing the relationship between extreme value timing (Ha) and extreme value (Hb) in each cylinder. [Figure 13] FIG. 13 is a diagram showing the relationship between the variation in extreme value timing and the average value of the extreme values ​​in a predetermined cycle. [Figure 14] FIG. 14A is a diagram showing an example of the trend in solar power generation and the trend in power demand when surplus power is generated, and FIG. 14B is a diagram showing an example of the trend in solar power generation and the trend in power demand when no surplus power is generated. [Figure 15] FIG. 2 is a diagram showing the relationship between an extreme value (Hb) and an extreme value timing (Ha) in a specific cylinder. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functions or configurations are designated by the same reference numerals, and redundant description will be omitted.

[0013] 1 is a schematic diagram of a partially hydrogen fueled engine system 20. The engine system 20 includes an engine 18 that is partially fueled by hydrogen. In the engine system 20, a first fuel, for example, a hydrocarbon fuel, is directly injected into a combustion chamber 2 by an injector 4 (an example of a fuel injection device). The first fuel supplied to the combustion chamber 2 is compressed by a piston 1 to a high temperature and pressure, and in this state the first fuel self-ignites and burns, generating torque in the piston 1. The up and down movement of the piston 1 is converted into the rotational movement of a crankshaft 17. A generator (not shown) is connected to the crankshaft 17, and generates electricity as the crankshaft 17 rotates.

[0014] A throttle valve 3 is provided in an intake pipe of the engine 18, and the amount of air taken from the intake pipe into the combustion chamber 2 is changed by adjusting the opening of the throttle valve 3 by the engine controller 11. The opening of the throttle valve 3 is detected by an opening sensor (not shown) and output to the engine controller 11.

[0015] The second fuel, gas fuel, is supplied to the intake pipe of the engine by a flow rate control device 6, and mixed with air and supplied to the combustion chamber 2. In the combustion chamber 2, the premixture of the second fuel and air is heated and combusted by the self-ignition combustion of the first fuel. Such combustion of the first fuel and the second fuel is referred to as "dual combustion" and will be described below.

[0016] The second fuel is a gas containing hydrogen as a fuel, such as hydrogen-rich gas, natural gas containing hydrogen in part, biogas containing hydrogen in part, synthetic gas containing hydrogen in part, ammonia, reformed gas, etc. The reformed gas is, for example, a gas obtained by reforming natural gas, biogas, biofuel such as ethanol, ammonia, or synthetic fuel. The hydrogen generator 5 and the flow rate regulator 6 are used as an example of a second fuel supply device that supplies fuel containing hydrogen in part to the engine (engine 18) as the second fuel.

[0017] As the hydrogen generator 5, for example, an electrolyzer that decomposes water into hydrogen and oxygen, or a reformer with a catalyst inserted, etc. is used. When the hydrogen generator 5 is an electrolyzer, the electricity supplied is electricity generated from renewable energy sources such as solar power generation and wind power generation. When the hydrogen generator 5 is a reformer, a hydrocarbon fuel or ammonia is supplied to the reformer, and either or both of engine exhaust heat and coolant heat are supplied to the reformer.

[0018] The hydrogen co-firing electronic control device 12 may supply electricity to the reformer to operate it. A hydrogen storage device (not shown) may be provided between the hydrogen generation device 5 and the flow rate adjustment device 6. Here, the hydrogen storage device may be, for example, a hydrogen tank, a hydrogen storage alloy, or an organic hydride. The hydrogen storage device stores hydrogen generated by the hydrogen generation device 5 and can extract hydrogen upon request from the flow rate adjustment device 6. When a hydrogen storage alloy or an organic hydride is used, one or both of engine exhaust heat and coolant heat are supplied.

[0019] An engine controller 11 controls the injection timing of the first fuel from the injector 4 based on signals from a crank angle sensor 7 and a cam sensor 8 that detect the rotation timing of the engine. The injection timing of the first fuel is controlled based on the engine speed, torque, and a signal from an oxygen concentration sensor 10 in the exhaust. Since the second fuel contains some hydrogen, dual combustion is achieved even when the premixture of the second fuel and air has an air excess ratio greater than the stoichiometric ratio, that is, a high air excess ratio condition. Therefore, dual combustion is achieved by adding the second fuel to the intake air of a conventional diesel combustion engine.

[0020] The hydrogen co-fuel electronic control device 12 is a device that controls the mixture ratio of hydrogen to be co-fueled in the combustion chamber (combustion chamber 2) of the hydrogen co-fuel engine (engine 18) having the above-mentioned first fuel supply device and second fuel supply device. The hydrogen co-fuel electronic control device 12 detects the engine combustion timing based on the detection results of the crank angle sensor 7 and the cam sensor 8. Then, the hydrogen co-fuel electronic control device 12 controls the flow rate adjustment device 6 and the hydrogen generation device 5 based on the detected engine 18 combustion timing, and controls the flow rate of hydrogen supplied to the engine 18.

[0021] The energy management system 13, together with the hydrogen co-firing electronic control device 12 and multiple hydrogen co-firing engines, constitutes a power generation system. The energy management system 13 is provided separately from the engine system 20, and manages the overall energy, including the energy including renewable energy and the fuel energy used in the engine system 20. For example, the energy management system 13 manages the overall renewable energy generated by a solar power generation system or the like, and the fuel energy of the engine system 20 controlled by the hydrogen co-firing electronic control device 12. Therefore, one energy management system 13 can manage the energy of multiple engine systems 20. For example, the engine controller 11 and the hydrogen-mixed combustion electronic control device 12 are installed in a factory, and the energy management system 13 is installed in the same factory or on the cloud. Therefore, the energy management system 13 can also manage the energy of the engine controller 11 and the hydrogen-mixed combustion electronic control device 12 that are installed in places remote from each other.

[0022] The hydrogen co-firing electronic control device 12 has a function of communicating information with an energy management system 13 including renewable energy, and controls the flow rate adjustment device 6 and the hydrogen generation device 5 based on the energy supply and demand balance of the energy management system 13.

[0023] The engine system status and control implementation details detected by the hydrogen-mixed combustion electronic control device 12 are communicated to the energy management system 13, making it possible to formulate a hydrogen production plan in the energy management system 13. The hydrogen-mixed combustion electronic control device 12 may be implemented inside the engine controller 11. The intake air temperature and water temperature during engine operation are detected by temperature detection devices 14 and 15. The temperature detection device 14 may also have a function of detecting the humidity of the intake air.

[0024] Fig. 2 is a diagram showing the 100-cycle average of the engine combustion pressure waveform. The horizontal axis of Fig. 2 shows the crank angle [deg. ATDC], and the vertical axis shows the in-cylinder pressure [MPa]. The hydrogen mixture ratio, which is the ratio of hydrogen in the total fuel supplied to the engine 18, is changed to 0%, 20%, 40%, 55%, and 60%, and the 100-cycle average of the measured combustion pressure is shown as the combustion pressure waveform.

[0025] As shown in Figure 2, as the hydrogen mixture ratio increases, the combustion pressure rises earlier, the maximum pressure increases, and the timing of the combustion center of gravity (plotted point in the figure) comes earlier. The timing of the combustion center of gravity is defined as the point at which the amount of heat generated by combustion reaches 50% of the heat generated by the fuel supplied. Comparing hydrogen mixture ratios of 55% and 60%, we can see that despite a 5% increase in hydrogen mixture ratio, there is a large difference in the rise in maximum pressure and the timing of the combustion center of gravity, resulting in a large difference in the combustion pressure waveforms. This is because the 60% hydrogen mixture ratio includes cycles in which abnormal combustion occurs.

[0026] Fig. 3 is a diagram showing an example of a combustion pressure waveform for each cycle. The horizontal axis of Fig. 3 indicates time, and the vertical axis indicates combustion pressure. The upper part of Fig. 3 shows an example of a combustion pressure waveform for each cycle when the hydrogen mixing ratio is 60%. The lower part of Fig. 3 shows an enlarged view of the combustion pressure waveform included in a rectangular frame 30 at the left end of the combustion pressure waveform in Fig. 3. As shown in Fig. 3, when the hydrogen mixing ratio becomes 60%, the number of cycles in which abnormal combustion occurs increases.

[0027] The apex 31 of the combustion pressure waveform shown in the lower part of FIG. 3 shows the characteristics of the combustion pressure waveform when knocking occurs when the hydrogen mixture ratio is equal to or higher than a predetermined value at which abnormal combustion is likely to occur. When the hydrogen ratio is equal to or higher than a predetermined value, the probability of such combustion occurring increases. In addition, the higher the temperature of the air supplied to the engine and the temperature of the engine coolant, the higher the probability of knocking occurring. Another example of abnormal combustion is pre-ignition, which occurs earlier than a predetermined timing due to hot surface ignition that occurs when contact is made with a high-temperature member in the combustion chamber of the engine. Like knocking, pre-ignition is also likely to occur under conditions where the hydrogen mixture ratio, intake air temperature, and coolant temperature are high.

[0028] If such abnormal combustion occurs in the engine 18, the timing of the center of combustion cannot be controlled within a normal timing range, resulting in a deterioration in thermal efficiency, a delay in the timing of the pressure rise in the combustion chamber 2, and the occurrence of high-frequency pressure pulsations, which may cause engine breakdown. Therefore, in order to prevent engine breakdown, it is necessary to implement adjustment control, such as reducing the amount of hydrogen supply.

[0029] As mentioned above, abnormal combustion occurs when environmental conditions such as changes in outside air temperature occur or when there is a transient change in the engine. Therefore, the engine controller 11 and the hydrogen-mixed combustion electronic control device 12 need to detect the combustion of the engine 18 in real time and grasp the combustion state.

[0030] Another issue is that when the amount of secondary fuel supplied is small and the hydrogen mixing ratio is low, some of the secondary fuel containing the supplied hydrogen may be exhausted without being burned in the combustion chamber. For example, in Figure 2, when comparing hydrogen mixing ratios of 0% and 20%, there is almost no change in the waveform. Under such conditions, the secondary fuel containing hydrogen does not contribute to combustion, so the thermal efficiency of the engine decreases. In addition, there is a safety concern when unburned hydrogen is exhausted outside the engine.

[0031] As described above, cases where hydrogen is discharged unburned occur easily when the hydrogen mixture ratio is low. Hydrogen is a component that is more easily combusted under excess air conditions than hydrocarbon fuels, but when the excess air ratio of the mixture of the inhaled hydrogen and the intake air is 8 to 10 or more, it falls outside the flammable range. In addition, regarding flammability at a low hydrogen mixture ratio, the hydrogen mixture ratio that is the threshold at which unburned hydrogen is discharged changes depending on the outside air temperature and the cooling water temperature. Furthermore, since the supercharging pressure and temperature of the intake air change depending on the operating conditions of the engine 18, such as the engine speed and torque, the hydrogen mixture ratio that is the threshold also changes depending on the operating conditions of the engine 18. For these reasons, it is necessary to detect the combustion state in real time and grasp the combustibility of the hydrogen supplied to the combustion chamber 2.

[0032] Here, it is conceivable to detect the combustion state by installing a cylinder pressure sensor for each cylinder and grasping the history of the cylinder pressure during combustion, but this would require additional costs and space for installation. Therefore, in the electronic control device for hydrogen-mixed combustion according to this embodiment, the crank angle sensor 7, which is a rotation sensor for the crankshaft 17, is used. Use and burning state Detect.

[0033] FIG. 4 is a diagram showing an example of the arrangement of the cylinders 41, the crankshaft 17, the camshaft 42, and the controller. The four cylinders 41 shown in the figure are numbered "1" to "4." Use and burning condition The cam sensor 8 connected to the camshaft 42 is used to grasp the reference rotational position.

[0034] The hydrogen-mixed combustion electronic control device 12 according to this embodiment will be described with reference to Figures 5, 6, and 7. Figure 5 is a block diagram showing an example of the internal configuration of the hydrogen-mixed combustion electronic control device 12. The hydrogen-mixed combustion electronic control device 12 includes a filter 60, a square wave conversion circuit 61, a microcomputer calculation unit 62, and a storage device 70.

[0035] FIG. 6 is a diagram showing an example of an electromagnetic pickup signal in a method using an electromagnetic pickup. The vertical axis indicates voltage [V], and the horizontal axis indicates time. As shown in FIG. 6, in a method using an electromagnetic pickup, a voltage is output with a period proportional to the rotation speed of the detection gear of the rotating shaft, and the output signal is input to a square wave conversion circuit 61. The square wave conversion circuit 61 generates a square wave that switches between ON and OFF at the point where the electromagnetic pickup crosses 0V, and outputs it to a microcomputer calculation unit 62. When a hall element is used, the output signal is taken into the microcomputer calculation unit 62. A filter 60 may be used to remove gear characteristics and noise for both the electromagnetic pickup and the hall element.

[0036] The filter 60 is, for example, a low-pass filter with a cutoff frequency set to 10 kHz or higher. Alternatively, a moving average filter or the like may be used. The microcomputer calculation unit 62 has a rotation time profile calculation unit 63 , an extreme value / extreme value timing calculation unit 64 , a combustion state determination unit 65 , an abnormal combustion cylinder extraction unit 66 , a combustion abnormality determination unit 67 , and a control mode determination unit 68 .

[0037] The rotation time profile calculation unit 63 detects a physical quantity corresponding to the rotation time between edges for each edge using the falling edge of the square wave as a trigger, and obtains a rotation time profile that is a profile of the time change. Note that the rising edge may also be used as a trigger.

[0038] FIG. 7 is a diagram showing an example of a rotation time profile in the case of a four-cylinder engine. The vertical axis indicates angular velocity, and the horizontal axis indicates crank angle. As shown in FIG. 7, in the case of a four-cylinder engine, four minimum and four maximum extreme values ​​of angular velocity are detected during two rotations of the crankshaft. The extreme value and extreme value timing calculation unit 64 calculates the following from the rotation time profile output from the rotation time profile calculation unit 63: angular velocity Timing of extreme values ​​(Ha) and angular velocityThe extreme value (Hb) of is calculated. At this time, by using Fourier series expansion and signal processing, it is possible to ignore the individual difference of the detection gear of the rotating shaft of the electromagnetic pickup. Here, the extreme value may be either the maximum value or the minimum value, but in this embodiment, the extreme value (Hb) is angular velocity is defined as the maximum value of

[0039] The combustion state determination unit 65 determines the combustion state based on the extreme value timing (Ha) and the extreme value (Hb). FIG. 10 is a diagram showing the correlation between the extreme value timing (Ha) and the combustion center timing (MFB50 timing). As shown in FIG. 10, the extreme value timing (Ha) shows a correlation with the combustion center timing (MFB50 timing). In general, when the hydrogen mixture ratio increases, the MFB50 timing is advanced, and therefore the extreme value timing (Ha) is also advanced, that is, becomes a smaller value. If the extreme value timing (Ha) does not change even though the hydrogen mixture ratio is increased, the combustion state determination unit 65 determines that a misfire has occurred because the combustion center has not been advanced by the supply of hydrogen.

[0040] On the other hand, when the hydrogen mixing ratio is increased to a value greater than a predetermined value, the extreme value timing (Ha) becomes smaller (advanced), and at that time, the extreme value (Hb) becomes greater than a predetermined value, or the variation in the extreme value timing (Ha) becomes greater than a predetermined value. This phenomenon will be described with reference to Figures 11A and 11B. Fig. 11A is a diagram showing plot points for each cycle during normal combustion, and Fig. 11B is a diagram showing plot points for each cycle during abnormal combustion. In each diagram, the vertical axis shows the extreme value (Hb) and the horizontal axis shows the extreme value timing (Ha).

[0041] As shown in Fig. 11A, in normal combustion, when the hydrogen mixing ratio is increased, the extreme value timing (Ha) becomes smaller. On the other hand, as shown in Fig. 11B, the extreme value (Hb) during abnormal combustion becomes larger than a predetermined value (e.g., when the hydrogen mixing ratio is small). Also, the variation range of the extreme value timing (Ha) during abnormal combustion becomes larger than a predetermined value (e.g., the variation range of the extreme value timing (Ha) during normal combustion). In such a case, the combustion state determination unit 65 determines that plague or knocking has occurred.

[0042] The combustion abnormality judgment unit 67 determines a threshold value for the average value (AHb) of the extreme value (Hb) over a predetermined number of cycles and a threshold value for the variation in the extreme value timing (Ha) over a predetermined number of cycles based on information such as the combustion abnormality judgment value for each cylinder stored in the memory device 70, environmental conditions, and operating conditions, and uses this information to judge whether or not there is a combustion abnormality.

[0043] Here, the predetermined number of cycles is one or more, and the number of cycles is determined according to the operating characteristics. For example, in operation under steady conditions, the number of cycles is set to 10 or more, and in operation under transient conditions, it is set to 10 or less. In addition, here, the threshold value for the variation is determined using an index such as standard deviation, variance, or coefficient of variation. The threshold value for the average value and the threshold value for the variation may be set for each cylinder. By setting the threshold value for each cylinder, abnormal combustion can be accurately detected. In this embodiment, the variation will be described using the coefficient of variation (Cv).

[0044] FIG. 15 is a diagram showing the relationship between the extreme value (Hb) and the extreme value timing (Ha) in a predetermined cylinder. Depending on the hydrogen mixing ratio in the fuel supplied to the engine, the combustion center of gravity timing (MFB50 timing) changes, and thus the extreme value timing (Ha) changes. Specifically, as the hydrogen mixing ratio increases, the value of the extreme value timing (Ha) decreases. That is, it advances. And when abnormal combustion such as preignition or knocking occurs under conditions of a high hydrogen mixing ratio, the extreme value (Hb) increases, and the value of the average value A Hb of the extreme value in a predetermined cycle becomes larger than the threshold value L Hb. Also, the variation (Cv) of the extreme value timing becomes large and becomes equal to or greater than the threshold value L Cv. Therefore, when the average value (A Ha) of the extreme value timing (Ha) in a predetermined cycle satisfies a condition such as being smaller than a predetermined value, for example, the combustion abnormality determination unit 67 performs the following determination.

[0045] FIG. 9 is Extreme values a diagram showing combustion abnormality determination using the extreme value and the extreme value timing. When A Hb < L Hb and Cv < L Cv, abnormal combustion does not occur. Therefore, the combustion abnormality determination unit 67 determines normal combustion. When A Hb > L Hb and Cv < L Cv, the combustion abnormality determination unit 67 determines that abnormal combustion such as preignition or knocking frequently occurs (abnormality A). In this case, the combustion torque becomes higher than a predetermined value, and A Hb becomes larger than L Hb. And since the combustion center of gravity occurs stably at an early timing, Cv < L Cv. When A Hb < L Hb and Cv > L Cv, the combustion abnormality determination unit 67 determines that knocking or misfire has occurred because the combustion torque does not become larger than a predetermined value but the combustion center of gravity fluctuates (abnormality C). When A Hb > L Hb and Cv > L Cv, since the combustion torque becomes larger than a predetermined value and the combustion center of gravity fluctuates, the combustion abnormality determination unit 67 determines that abnormal combustion such as preignition or knocking occurs not every cycle but occurs (abnormality B).

[0046] The abnormal combustion cylinder extraction unit 66 identifies the cylinder in which abnormal combustion is occurring based on the detection results of the crank angle sensor 7 and the cam sensor 8. By grasping the reference rotation position with the cam sensor 8, the extreme value timing (Ha) and extreme value (Hb) for each cylinder are extracted.

[0047] When the rotation time is detected by the crank angle sensor 7, the change in the rotation speed is subject to torque interference for each cylinder. In the case of an engine generator, the engine controller 11 controls the rotation speed of the engine 18 to be within a predetermined range. Therefore, when a certain cylinder experiences combustion abnormality and the rotation speed of the crankshaft 17 changes, the engine controller 11 controls another cylinder so that the direction of change in the rotation speed becomes opposite to that of the cylinder. Therefore, when abnormal combustion occurs in any cylinder, some cylinders will be affected by the abnormal combustion cylinder among the cylinders with normal combustion. Since the control cycle of the engine is 2 to 10 ms, the cylinders with normal combustion will be affected by the cylinder with abnormal combustion within that control cycle.

[0048] A method for identifying a cylinder when an abnormality occurs will be described with reference to FIG. 12. FIG. 12 is a diagram showing the relationship between the extreme value timing (Ha) and the extreme value (Hb) in each cylinder. As shown in FIG. 12, the cylinder with abnormal combustion has a large extreme value (Hb) and a large variation in the extreme value timing (Cv). The cylinder with normal combustion that is affected by the cylinder with abnormal combustion is controlled so that the direction of change in the rotation speed is opposite to that of the rotation speed, so that the extreme value (Hb) becomes small and the variation in the extreme value timing (Cv) becomes large. Therefore, by checking the extreme value timing (Ha) and extreme value (Hb) of each cylinder, it is possible to determine the cylinder with abnormal combustion.

[0049] When plague or knocking occurs in a particular cylinder, the occurrence of abnormal combustion can be suppressed by reducing the amount of hydrogen supply. As shown in Figure 15, generally, when the hydrogen mixture ratio is increased, the value of the extreme value timing (Ha) decreases. When abnormal combustion occurs, the value of the extreme value (Hb) increases and the variation in extreme value timing (Cv) increases, making it possible to detect abnormal combustion. When abnormal combustion is detected, the hydrogen mixture ratio can be reduced, making it possible to determine the optimal hydrogen mixture ratio for that operating condition.

[0050] Also, a configuration may be adopted in which the amount of hydrogen supplied is adjusted for each cylinder. By adjusting the amount of hydrogen supplied for each cylinder, the amount of hydrogen supplied can be increased, and carbon dioxide emissions can be further reduced. As a method of adding hydrogen for each cylinder, for example, the amount of hydrogen supplied to each cylinder can be adjusted by controlling the drive pulse width of a hydrogen injector attached to each cylinder. Also, a configuration may be adopted in which the amount of conventional fuel supplied to each cylinder is adjusted by adjusting the injection pulse width of the conventional fuel supplied to each cylinder.

[0051] In this embodiment, a method for checking the extreme value timing (Ha) and extreme value (Hb) of each cylinder has been described, but a cylinder experiencing abnormal combustion can also be identified from the output signal of the crank angle sensor 7 or the characteristics of the rotation time profile after signal processing.

[0052] A control mode determination unit 68 determines a control mode for the engine 18 based on the extraction result from the abnormal combustion cylinder extraction unit 66. Fig. 13 is a diagram showing the relationship between the variation (Cv) of the extreme value timing and the average value (AHb) of the extreme values ​​in a predetermined cycle. Control (a) is implemented when abnormality A occurs. Because abnormal combustion such as plague and knocking occurs frequently, the hydrogen supply is immediately stopped and the combustion is switched to conventional fuel only. Control (b) is implemented when abnormality B occurs. Since abnormal combustion such as plague or knocking occurs not every cycle, but in this situation, the amount of hydrogen supplied is reduced and the hydrogen mixture ratio is made smaller, making it possible to eliminate the occurrence of abnormal combustion. Control (c) is implemented when abnormality C occurs. The hydrogen mixture ratio is fine-tuned while referring to the value of the extreme value timing variation (Cv), and the resultant value is used to determine whether the cause was misfire or knocking. If the hydrogen mixture ratio is increased and Cv becomes smaller, it is determined that misfire was the cause. Conversely, if the hydrogen mixture ratio is increased and Cv becomes larger, it is determined that knocking has occurred.

[0053] The control mode determination unit 68 stores in the storage device 70 the relationship between the hydrogen mixing ratio and operating conditions such as engine speed and torque before and after each control is performed.

[0054] In the microcomputer calculation unit 62 of the hydrogen co-firing electronic control device 12, these calculations can be performed with access to the memory device 70, making it possible to utilize information obtained in advance or in real time, thereby improving the accuracy of the calculations. Specifically, the type of abnormal combustion occurrence (Abnormalities A, B, and C in FIG. 13), the operating conditions (engine speed, torque, hydrogen mixing ratio) and environmental conditions (intake air temperature, water temperature) when the abnormal combustion occurred are stored in the storage device 70 as operating records. Also, various thresholds are stored in the storage device 70. The thresholds to be stored include, for example, a threshold LCv for the variation in extreme value timing and LHb, which is a threshold for the average value AHb of the extreme values, which are stored for each operating condition and environmental condition.

[0055] Also, the configuration may be such that thresholds of the supplyable hydrogen amount condition obtained from the energy management system 13 are stored. The hydrogen amount condition is determined by the energy management system 13 according to the generation plan of the hydrogen generation device. Specifically, the thresholds of the hydrogen amount condition are large during times when the amount of power generated by renewable energy such as solar power generation is large and surplus power is generated, since a large amount of hydrogen can be generated. These thresholds can be updated or stored at intervals of 1 second or more.

[0056] Furthermore, when calculating AHb and Cv, a predetermined number of cycles are acquired, and in order to calculate the average value and variation, a predetermined number of cycles are stored in storage device 70. This is stored in real time when the engine is operating, so the stored data is updated at intervals of 10 ms or less.

[0057] Fig. 8 is a diagram showing the control flow of the hydrogen-mixed combustion electronic control unit 12. The hydrogen-mixed combustion electronic control unit 12 performs the determination process shown in Fig. 8, and controls the flow rate adjustment device 6 that supplies fuel to the engine 18 based on the result of the process.

[0058] First, the signals from the cam sensor 8 and the crank angle sensor (rotation sensor) 7 are captured (S801). The signal from the crank angle sensor 7 is a signal converted into a 5V rectangular wave, and a profile of the change in time (rotation time) between edges is obtained for each edge (S802). Next, from the profile of the change in rotation time, Each cylinder The timing (Ha) and value (Hb) of the extremes are extracted (S803).

[0059] When cylinder identification is performed from the profile of the change in rotation time, the cam sensor 8 is utilized as a timing reference. If the signal from the cam sensor 8 cannot be obtained, cylinder identification may be performed from extreme values ​​under specified operating conditions. For example, when operating under stable combustion conditions without supplying hydrogen, the average value (AHb) differs for each cylinder, so it is also possible to identify cylinders by comparing the initial AHb value with the obtained AHb.

[0060] Next, the average value (AHb) of the extreme values ​​in a predetermined cycle and the variation (Cv) of the timing of the extreme values ​​are calculated (S805). The predetermined cycle is selected within a range of 1 cycle to 200 cycles, and is selected according to the operating conditions and environmental conditions obtained in S804. For example, if steady operation is the norm, the above-mentioned predetermined cycles is set to a value of 10 or more, and if operation involves large transient changes, the above-mentioned predetermined cycles is set to a value of 10 or less. In the case of operation involving transient changes, the number of cycles must be reduced in order to obtain engine operation under the same conditions. The obtained data and operating conditions are then stored as a set in the storage device 70, and a judgment is made by combining this with past data on the same operating conditions.

[0061] On the other hand, during steady-state operation, a value of 10 cycles or more is selected, and the number of cycles is increased according to the degree of impact on analytical accuracy. For example, if analytical accuracy is low, the number of cycles is increased to 100-200, and conversely, if analytical accuracy is high, the number is set to 10-50 cycles. This makes it possible to improve analytical accuracy while shortening the time until an abnormality is detected.

[0062] The smaller the number of cycles acquired, the more quickly the determination can be made, making it possible to respond to sudden abnormal combustion. Also, the lower the number of cycles, the smaller the amount of data acquired in the storage device 70 can be. On the other hand, when the analysis accuracy is low, the higher the number of cycles acquired, the higher the accuracy can be. For example, the accuracy changes due to changes in fuel properties or changes in the state of engine parts, so that the variation in the analysis results (indicated by any one of the variance, standard deviation, or rate of change) may become large even when the engine operating conditions and environmental conditions are the same. Therefore, in such cases, the analysis accuracy can be improved by increasing the number of cycles acquired.

[0063] The presence or absence of abnormal combustion is confirmed based on the results of the average values ​​AHa and AHb of the extreme value timing (Ha) and extreme value (Hb) calculated in S805, and the variation (Cv) of the extreme value timing (S806). Next, if any of the following combustion abnormalities is detected: misfire, plague, or knocking, the cylinder in which the abnormality occurred is identified (S807), and then the abnormality mode of the abnormal cylinder is determined (S808). Furthermore, based on the result of identifying the cylinder in which abnormal combustion has occurred, the control mode is determined (S809).

[0064] The hydrogen amount conditions are determined by the energy management system 13 according to the generation plan of the hydrogen generation device. Hydrogen can be generated in large quantities from renewable energy, and the amount of hydrogen generated increases when there is a large amount of surplus electricity. Fig. 14A is a diagram showing an example of the transition of solar power generation and electricity demand when surplus electricity is generated. Fig. 14B is a diagram showing an example of the transition of solar power generation and electricity demand when no surplus electricity is generated.

[0065] As shown in Figure 14A, when weather forecasts and power demand forecasts indicate that solar power generation exceeds power demand during certain periods of time, the surplus power can be used to generate hydrogen. On the other hand, as shown in Figure 14B, when weather forecasts predict rain or cloudy weather and solar power generation falls short of power demand, the amount of power available for hydrogen generation will decrease.

[0066] In this way, when the time periods or scale of surplus electricity generated are large based on weather forecasts and power demand forecasts, the amount of hydrogen produced will be planned to be large, so the amount of hydrogen that can be supplied to the system will increase and the threshold value for the hydrogen amount condition will become higher.

[0067] The energy management system 13 has data on the predicted amount of hydrogen supply on a daily, weekly or monthly basis, and can determine the amount of hydrogen that can be supplied to the engine 18 based on this predicted data. Therefore, the energy management system 13 can be configured to create a hydrogen supply plan, which is a plan for the amount of hydrogen to be supplied to the hydrogen-mixed combustion electronic control device 12 based on environmental conditions, and the hydrogen-mixed combustion electronic control device 12 can determine the hydrogen mixing ratio for the engine 18 based on the hydrogen supply plan.

[0068] In addition, when the engine system 20 includes multiple engines 18, the hydrogen co-firing electronic control device may be configured to have a function of allocating the amount of hydrogen that can be supplied to each engine 18 from the amount of hydrogen that can be supplied by the energy management system 13. This allows the optimal amount of hydrogen to be allocated to each engine 18 according to the state of the engine 18, and the amount of hydrogen supply can be appropriately controlled according to the characteristics of the engine 18 and environmental changes. This allows the amount of hydrogen supply to be controlled within a range where abnormal combustion does not occur, and the amount of hydrogen supply can be appropriately controlled according to the engine characteristics and environmental changes. In addition, by maximizing the amount of hydrogen supply, it is possible to maximize the reduction in CO2 emissions from the engine 18.

[0069] Finally, the extreme value timing (Ha) corresponding to the combustion abnormality state (misfire, plague, knocking), the threshold value of the extreme value (Hb) and the cylinder in which the combustion abnormality occurred, the variation (Cv) of the extreme value timing (Ha) in a given cycle, the environmental conditions in which the engine 18 is installed, the operating conditions (for example, engine water temperature, intake temperature, intake humidity, fuel injection timing, ignition timing, etc.), etc. are stored in the storage device 70 as history information (S810). Utilizing the information stored in the storage device 70 enables highly accurate abnormality determination corresponding to the external environment such as the outside air temperature and humidity and aging of the engine.

[0070] Incidentally, the present invention is not limited to the above-described embodiment, and it goes without saying that various other applications and modifications are possible without departing from the gist of the present invention as set forth in the claims. For example, the above-mentioned embodiment describes the system configuration in detail and specifically in order to explain the present invention in an easily understandable manner, and is not necessarily limited to a system having all of the described configurations. In addition, it is also possible to add, delete, or replace part of the configuration of the present embodiment with other configurations. In addition, the control lines and information lines shown are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. In reality, it can be considered that almost all components are connected to each other. [Explanation of symbols]

[0071] 1...piston, 2...combustion chamber, 4...injector, 5...hydrogen generation device, 6...flow rate adjustment device, 7...crank angle sensor, 8...cam sensor, 11...engine control controller, 12...electronic control device for hydrogen co-fuel combustion, 13...energy management system, 17...crankshaft, 18...engine, 20...engine system, 41...cylinder, 60...filter, 61 square wave conversion circuit, 62...microcomputer calculation unit, 63...rotation time profile calculation unit, 64...extreme value / extreme value timing calculation unit, 65...combustion state determination unit, 66...abnormal combustion cylinder extraction unit, 67...combustion abnormality determination unit, 68...control mode determination unit, 70...storage device

Claims

1. a first fuel supply device that supplies a first fuel directly to a combustion chamber of the engine; A hydrogen-mixed combustion electronic control device for controlling a mixing ratio of hydrogen mixed in a combustion chamber of a hydrogen-mixed combustion engine having a second fuel supply device that supplies hydrogen-rich gas as a second fuel to the engine, a crank angle sensor for detecting an angular velocity of a crankshaft of the engine; a calculation unit that calculates an extreme value timing and an extreme value of the angular velocity with respect to the crank angle of the crankshaft based on a detection result of the crank angle sensor, determining a combustion state of the engine based on the extreme value timing and the extreme value; The mixing ratio of the hydrogen is adjusted based on the extreme value timing and the extreme value. Electronic control device for hydrogen co-firing.

2. The electronic control device for hydrogen co-fuel combustion according to claim 1, an electronic control device for hydrogen-mixed combustion that determines at least one of abnormal combustion and misfire in the engine based on the extreme value timing and the extreme value;

3. The electronic control device for hydrogen co-fuel combustion according to claim 1, an electronic control device for hydrogen-mixed combustion that determines abnormal combustion and sets the proportion of hydrogen supplied to the engine to zero when the average value of the extreme values ​​for a specified number of cycles exceeds a first specified value and the variation in the timing of the extreme values ​​for the specified number of cycles is equal to or less than a second specified value.

4. The electronic control device for hydrogen co-fuel combustion according to claim 1, an electronic control device for hydrogen-mixed combustion that determines abnormal combustion and reduces the amount of hydrogen supplied to the engine when the average value of the extreme values ​​for a specified number of cycles exceeds a first specified value and the variation in the timing of the extreme values ​​for the specified number of cycles exceeds a second specified value.

5. The electronic control device for hydrogen co-fuel combustion according to claim 1, When an average value of the extreme values ​​for a predetermined number of cycles is equal to or smaller than a first predetermined value and a variation in the extreme value timing for the predetermined number of cycles is higher than a second predetermined value, If the variation in the extreme value timing is reduced by increasing the hydrogen mixture ratio, it is determined that misfire is the cause, When the hydrogen mixing ratio is reduced and the variation in the extreme value timing increases, The electronic control device for hydrogen co-fuel combustion determined that abnormal combustion was the cause.

6. The electronic control device for hydrogen co-fuel combustion according to any one of claims 3 to 5, The first and second predetermined values ​​are set based on one or more of historical information about the engine, operating conditions of the engine, and environmental conditions in which the engine is installed.

7. The electronic control device for hydrogen co-fuel combustion according to any one of claims 3 to 5, The predetermined number of cycles is set based on at least one of historical information of the engine, operating conditions of the engine, and environmental conditions in which the engine is installed.

8. The electronic control device for hydrogen co-fuel combustion according to claim 1, The engine has a plurality of cylinders, and an electronic control device for hydrogen-mixed combustion that extracts cylinders in which abnormal combustion occurs based on the extreme value timing and the extreme value for each cylinder.

9. An electronic control device for hydrogen co-fuel combustion according to claim 8, an electronic control device for hydrogen-mixed combustion that changes the hydrogen mixture ratio in a cylinder determined to be experiencing abnormal combustion among the plurality of cylinders;

10. The electronic control device for hydrogen co-fuel combustion according to claim 1, When the combustion state of the engine is determined, An electronic control device for hydrogen-mixed combustion that stores in a storage device at least one of the cylinder in which a combustion abnormality occurred, the engine water temperature, the intake air temperature, the intake air humidity, the fuel injection timing, and the ignition timing as history information.

11. An electronic control device for hydrogen co-fuel combustion according to claim 10, A power generation system including a plurality of hydrogen-mixed combustion engines and an energy management system that provides information to the hydrogen-mixed combustion electronic control device, The hydrogen-mixed combustion electronic control device is a power generation system that determines the amount of hydrogen to be supplied to each of the multiple hydrogen-mixed combustion engines based on at least one of the environmental conditions in which the engines are installed, the amount of hydrogen that can be supplied to the power generation system, or the historical information.

12. An electronic control device for hydrogen co-fuel combustion according to claim 10, A power generation system including a plurality of hydrogen-mixed combustion engines and an energy management system that provides information to the hydrogen-mixed combustion electronic control device, the energy management system creates a hydrogen supply plan, which is a plan for the amount of hydrogen to be supplied to the hydrogen-mixed combustion electronic control device, based on the environmental conditions in which the engine is installed; The hydrogen-mixed combustion electronic control device determines the hydrogen mixing ratio for the multiple hydrogen-mixed combustion engines based on the hydrogen supply plan.

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