Crank angle sensor control unit and internal combustion engine control unit

Abstract

The crank angle sensor control device of the present invention includes: a buffer unit for storing signal information of a crank angle sensor for a specified period, wherein the crank angle sensor is used to detect signal teeth formed on a crank disk; and an output processing unit, which, upon detecting a tooth notch position on a crank disk serving as a reference position of the crank disk, outputs the signal information stored in the buffer unit during the period from detecting the tooth notch position to detecting a specified number of signal teeth.

Description

Technical Field

[0001] The present invention relates to a crank angle sensor control device and an internal combustion engine control device. Background Art

[0002] In recent years, regulations on fuel consumption (fuel efficiency) and harmful exhaust gases in vehicles such as automobiles have been tightened, and these regulations are likely to intensify further. Fuel efficiency regulations, in particular, are a matter of great concern due to rising fuel prices, the impact on global warming, and energy depletion.

[0003] Under these circumstances, technology is known for estimating the state within the engine's combustion chamber and controlling the engine based on the estimated results. By appropriately controlling ignition timing and fuel injection timing according to the current combustion state, engine thermal efficiency can be improved. For example, Patent Document 1 discloses a method for achieving such combustion state estimation that is robust against external disturbances such as noise and employs a simple structure.

[0004] Patent Document 1 describes a technical proposal for "providing a simple, low-cost internal combustion engine control device capable of robustly estimating the combustion state based on the engine's rotational state." Furthermore, Patent Document 1 describes "a rotational speed calculation unit that calculates a crank rotational speed, an extreme value timing calculation unit that calculates the timing of the extreme value of the crank rotational speed calculated by the rotational speed calculation unit, and a combustion state estimation unit that estimates the combustion state based on the timing of the extreme value of the crank rotational speed calculated by the extreme value timing calculation unit."

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-190234 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] In recent years, hybrid vehicles, which use engine-generated electricity to feed electric motors to drive the vehicle's axles, have become increasingly popular. Hybrid systems avoid low-load, low-speed engine operation, which reduces thermal efficiency, thereby improving the overall thermal efficiency of the system.

[0010] On the other hand, hybrid systems often operate the engine at a high speed and constant load, resulting in smaller speed variations within the engine cycle compared to conventional engine vehicles. Furthermore, hybrid systems are more complex and have a greater number of components than those in conventional engine vehicles. Therefore, system simplification and cost reduction are key challenges.

[0011] In the internal combustion engine control device described in Patent Document 1, the engine speed is calculated based on the signal information of the crank angle sensor after input processing by the input and output unit, and the state in the engine combustion chamber is estimated based on this. Therefore, in order to estimate the state in the engine combustion chamber with high precision, it is necessary to provide a device for processing the signal information of the crank angle sensor with high precision. For example, when the combustion state is estimated based on the signal information of the crank angle sensor containing noise, it is believed that there is a possibility that the effect of internal combustion engine control cannot be fully achieved, or even the thermal efficiency is deteriorated. The technology described in Patent Document 1 focuses particularly on the control method of the received crank angle sensor signal information, and does not mention the accuracy of the crank angle sensor signal information.

[0012] The present invention has been made in view of the above-mentioned situation, and an object of the present invention is to improve the reliability of signal information of a crank angle sensor.

[0013] Technical solutions to problems

[0014] In order to solve the above-mentioned problems, a crank angle sensor control device of one embodiment of the present invention includes: a buffer section for storing signal information of a crank angle sensor for a specified period, wherein the crank angle sensor is used to detect signal teeth formed on a crank disk; and an output processing section, which, upon detecting a tooth notch position on a crank disk serving as a reference position of the crank disk, outputs the signal information stored in the buffer section during the period from detecting the tooth notch position to detecting a specified number of signal teeth.

[0015] Furthermore, an internal combustion engine control device according to one embodiment of the present invention includes the crank angle sensor control device described above and a combustion detection control unit that receives signal information from the crank angle sensor controller and performs processing related to combustion detection.

[0016] Effects of the Invention

[0017] According to at least one aspect of the present invention, even if external disturbance such as noise occurs in the signal information of the crank angle sensor, the reliability of the signal information of the crank angle sensor can be improved.

[0018] Other problems, structures, and effects than those described above will become clear from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram showing an example of the system configuration of a hybrid vehicle.

[0020] Figure 2 This is a schematic diagram showing an example of a cross section of an engine.

[0021] Figure 3This is an explanatory diagram showing the principle of detecting a signal tooth of a crank plate as a voltage signal using a crank angle sensor.

[0022] Figure 4 This is a block diagram showing a configuration example of a controller.

[0023] Figure 5 It is an explanatory diagram showing the processing flow of the crank angle sensor control unit.

[0024] Figure 6 This is a waveform diagram showing an example of a voltage signal of a crank plate.

[0025] Figure 7 This is a flowchart showing the processing flow of the rotation speed calculation unit of the controller.

[0026] Figure 8 This is an explanatory diagram showing a method for calculating time-series data of the cycle-averaged rotation speed.

[0027] Figure 9 This is a flowchart showing the processing flow of the extreme value timing calculation unit of the controller.

[0028] Figure 10 This is an explanatory diagram showing the sequence of each stroke of a three-cylinder four-stroke engine.

[0029] Figure 11 This is an explanatory diagram showing an example of a window set for each cylinder of a three-cylinder four-stroke engine.

[0030] Figure 12 This is an explanatory diagram showing an example of converting time series data (crank angle) of the rotation speed within a window into a local crank angle.

[0031] Figure 13 This is a graph for explaining a method for calculating the maximum timing of the engine speed.

[0032] Figure 14 This is a graph for explaining a method for calculating the minimum timing of the engine speed.

[0033] Figure 15 This is a characteristic diagram showing the correlation between the maximum timing of the engine speed and the position of the combustion center of gravity.

[0034] Figure 16 This is a characteristic diagram showing the correlation between the minimum timing of the engine speed and the position of the combustion center of gravity.

[0035] Figure 17 This is a characteristic diagram showing the correlation between the maximum timing of the engine speed and the initial combustion position.

[0036] Figure 18This is a characteristic diagram showing the correlation between the minimum timing of the engine speed and the initial combustion position.

[0037] Figure 19 This is a control block diagram of the ignition period in the controller.

[0038] Figure 20 This is a characteristic diagram showing the relationship between the initial combustion period and the periodic variation rate of the combustion torque.

[0039] Figure 21 It is the control block diagram of EGR in the controller.

[0040] Figure 22 This is a timing chart showing data transmission by a conventional crank angle sensor control unit (with noise mixed in).

[0041] Figure 23 This is a timing chart showing data transmission by the crank angle sensor control unit according to one embodiment of the present invention (with noise mixed in).

[0042] Figure 24 This is a control block diagram of a crank angle sensor control unit according to one embodiment of the present invention.

[0043] Figure 25 This is a control block diagram of a crank angle sensor control unit according to one embodiment of the present invention (at the time of abnormality determination (1)).

[0044] Figure 26 This is a control block diagram of a crank angle sensor control unit according to one embodiment of the present invention (at the time of abnormality determination (2)). DETAILED DESCRIPTION

[0045] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Components having substantially the same function or structure in this specification and the drawings are denoted by the same reference numerals, and repeated descriptions thereof will be omitted.

[0046] <One embodiment>

[0047] [System structure of hybrid vehicles]

[0048] First, a case where the structure of the present invention is applied to a system of a hybrid vehicle will be described as an example.

[0049] Figure 1 An example of a system configuration of a hybrid vehicle is shown.

[0050] Figure 1In the hybrid vehicle shown, an engine 1, a speed-increasing gear 2, and an induction generator 3 are connected in a row. The shaft output of the engine 1 is increased by the speed-increasing gear 2 to a speed suitable for the induction generator 3, thereby driving the induction generator 3. Furthermore, the speed-increasing gear 2 is configured as a variable gear system, allowing its speed-increasing ratio to be changed. The three-phase AC power generated by the induction generator 3 is converted to DC power by a rectifier 4 and then supplied to an inverter 6 and a battery 5. The DC power is further converted to three-phase AC power by the inverter 6 and supplied to an induction motor 7. The induction motor 7 drives the left and right wheels 9 via a transaxle 8.

[0051] The controller 12 is an example of a hybrid vehicle control device that controls the various components of the hybrid vehicle 50 and performs various data processing. For example, the controller 12 calculates the motor output required to drive the vehicle based on information about acceleration, braking, vehicle speed, and gear position, and controls the inverter 6 to supply a specified amount of power to the induction motor 7. Furthermore, the controller 12 manages the vehicle's overall powertrain by controlling the output of the engine 1, the speed-increasing ratio of the speed-increasing gear 2, and the excitation current of the induction generator 3. An ECU (Electronic Control Unit) is used as the controller 12, for example.

[0052] [engine]

[0053] Figure 2 An example of a cross section of the engine 1 is shown.

[0054] Engine 1 is an example of a spark-ignition four-stroke gasoline engine, in which a combustion chamber is formed by an engine cylinder head and cylinder 13, piston 14, intake valve 15, and exhaust valve 16. In engine 1, a fuel injection valve 18 is disposed in the engine cylinder head, and the nozzle of fuel injection valve 18 extends into the combustion chamber, thereby forming a so-called direct-injection internal combustion engine. In addition, a spark plug 17 is also disposed in the engine cylinder head. Combustion air is introduced into the combustion chamber through an air filter 19, a throttle valve 20, and an intake port 21. The combusted gas (exhaust gas) exhausted from the combustion chamber is then discharged into the atmosphere through an exhaust port 24 and a catalytic converter 25.

[0055] The amount of air introduced into the combustion chamber is measured by an air flow sensor 22 located upstream of a throttle valve 20. Furthermore, the air-fuel ratio of the gas (exhaust gas) exhausted from the combustion chamber is detected by an air-fuel ratio sensor 27 located upstream of a catalytic converter 25. Furthermore, a knock sensor 10 is installed in a cylinder block (not shown) that integrates the cylinder 13 with the crankcase. Knock sensor 10 outputs a detection signal corresponding to the amount of knocking in the combustion chamber.

[0056] The exhaust port 24 and the intake port 21 are connected by an EGR pipe 28, forming a so-called exhaust gas recirculation (EGR) system in which part of the exhaust gas flowing through the exhaust port 24 is returned to the interior of the intake port 21. The amount of gas flowing through the EGR pipe 28 is adjusted by an EGR valve 29.

[0057] Furthermore, a crank disk 26 (signal rotor) is provided on the shaft of the crankshaft 30. A crank angle sensor 11, located near the crank disk 26, detects the rotation and phase of the crankshaft, i.e., the crank speed, by detecting signals from the crank disk 26. The detection signals from the knock sensor 10 and the crank angle sensor 11 are input to the controller 12, where they are used to detect the state of the engine 1 and control its operation. Throughout this specification, the crank speed is also referred to as "engine speed" or simply "speed."

[0058] The controller 12 is an electronic control unit that outputs commands for the opening of the throttle valve 20, the opening of the EGR valve 29, the timing and amount of fuel injection from the fuel injection valve 18, and the ignition timing of the spark plug 17, thereby controlling the engine 1 to a predetermined operating state. For example, an ECU (Engine Control Unit) can be used as the controller 12.

[0059] in addition, Figure 2 In order to illustrate the structure of the combustion chamber of the engine 1 , only a single cylinder is shown. However, the engine 1 may be a multi-cylinder engine composed of a plurality of cylinders.

[0060] [Crank angle sensor]

[0061] Figure 3 The principle of detecting the signal teeth 26 a of the crank plate 26 as a voltage signal by the crank angle sensor 11 is shown.

[0062] Signal teeth 26a are arranged at regular angles Δθ on the circumference of the crank disk 26 mounted on the engine's crankshaft 30. As the engine 1 rotates, the signal teeth 26a pass the detection portion of the crank angle sensor 11, causing the voltage to rise. This voltage then decreases after a certain period of time. Based on this principle, the crank angle sensor 11 outputs Figure 6 The waveform of voltage signal 26b is shown. While this embodiment describes a voltage increase when the detection unit is added, there are also cases where the voltage decreases and then increases after a certain period of time. Regardless, the signal 26a output by crank angle sensor 11 is a waveform having a transition point when it passes through the detection unit of crank angle sensor 11.

[0063] [Controller]

[0064] Figure 4 1 is a block diagram showing a configuration example of the controller 12 .

[0065] The controller 12 includes an input / output unit 121 , a control unit 122 , and a storage unit 123 , which are electrically connected to one another via a system bus (not shown).

[0066] The input / output unit 121 has an input port and an output port (not shown) and performs input and output processing for various devices and sensors in the vehicle. For example, the input / output unit 121 reads a signal from a crank angle sensor and sends the signal to the control unit 122 .

[0067] The control unit 122 is a processing unit, and a CPU (central processing unit) or an MPU (micro processing unit) can be used. In addition, the input / output unit 121 outputs control signals to each device according to the command of the control unit 122.

[0068] The control unit 122 controls the vehicle's powertrain. For example, based on the combustion phase of the internal combustion engine 1, the control unit 122 controls the ignition timing, fuel injection timing, fuel injection amount, throttle opening, and EGR opening. The control unit 122 includes a crank angle sensor control unit 201, a combustion detection control unit 202, and an engine control unit 203.

[0069] The crank angle sensor control unit 201 (an example of a crank angle sensor control device) calculates the time interval Δt between the signal teeth 26a based on the voltage signal output by the crank angle sensor 11, buffers the calculated time interval Δt in the buffer memory for a predetermined period, and then outputs it as buffer information to the combustion detection control unit 202. The crank angle sensor control unit 201 and the control unit 122 each have a processor and a memory for calculation. For example, the buffer memory can use the memory and registers possessed by the crank angle sensor control unit 201. In addition, the crank angle sensor control unit 201 determines the reliability of the buffer information and outputs the determination result to the combustion detection control unit 202. The details of the crank angle sensor control unit 201 are described later. Figure 5 、 Figure 6 、 Figures 23 to 26 Provide explanation.

[0070] The crank angle sensor control unit 201 and the combustion detection control unit 202 are connected via an interface 204. The crank angle sensor control unit 201 outputs buffer information and a reliability determination result (described later) to the combustion detection control unit 202 via the interface 204.

[0071] The combustion detection control unit 202 detects the combustion state in the combustion chamber of the engine 1. The combustion detection control unit 202 is composed of a rotation speed calculation unit 202a, an extreme value timing calculation unit 202b, and a combustion phase calculation unit 202c.

[0072] The rotation speed calculation unit 202 a averages the time series data of the engine rotation speed and removes harmonic components, and outputs the obtained time series data of the engine rotation speed to the extreme value timing calculation unit 202 b .

[0073] The extreme value timing calculation unit 202b obtains the crank angle timing at which the engine speed reaches a maximum value or a minimum value based on the time series data of the engine speed input from the speed calculation unit 202a, and outputs the result to the combustion phase calculation unit 202c.

[0074] The combustion phase calculation unit 202 c calculates the combustion phase as an index representing the combustion state based on the maximum value timing or minimum value timing of the engine speed calculated by the extreme value timing calculation unit 202 b , and outputs the result to the engine control unit 203 .

[0075] The engine control unit 203 controls the engine 1 based on the combustion phase determined by the combustion phase calculation unit 202c. The engine control unit 203 is configured to have an ignition control function for controlling ignition based on the combustion phase and an EGR control function for controlling EGR based on the combustion phase.

[0076] The storage unit 123 is a volatile memory such as RAM (Random Access Memory) or a nonvolatile memory such as ROM (Read Only Memory). The storage unit 123 stores control programs executed by the control unit 122 (processing unit) included in the controller 12. The control unit 122 implements the functions of its modules by reading and executing the control programs from the storage unit 123. The controller 122 may also include a nonvolatile auxiliary storage device such as a semiconductor memory to store the control programs.

[0077] [Crank angle sensor control unit]

[0078] Next, the processing flow of the crank angle sensor control unit 201 will be described.

[0079] Figure 5 The following shows the processing flow of the crank angle sensor control unit 201.

[0080] Figure 6 2 is a waveform diagram showing an example of the voltage signal 26 b of the crank plate 26 .

[0081] In the crank angle sensor control unit 201, first, based on the voltage signal 26b (reference signal 26b) of the crank plate 26 detected by the crank angle sensor 11, Figure 6), calculate the time interval Δt between the signal teeth 26a (S1). The time interval Δt represents the time period of the ON signal of the voltage signal 26b obtained based on the signal teeth 26a arranged at a certain angular interval Δθ.

[0082] Next, the crank angle sensor control unit 201 executes a buffering process (S2) to store information about a predetermined time interval Δt between each signal tooth. The predetermined period is preferably at least two cycles, as combustion phasing calculations are required for each cylinder, as described below. For example, for a three-cylinder engine, this is 480 degrees, and for a four-cylinder engine, this is 360 degrees.

[0083] Finally, the crank angle sensor control unit 201 generates transmission data including buffer information regarding the buffering time interval Δt (buffer data 26c), and periodically outputs this transmission data to the rotation speed calculation unit 202a via the interface 204 (S3). To ensure accurate combustion phasing calculation, it is preferable to output buffer data 26c at least once per cycle. For example, for a three-cylinder engine, this data needs to be output every 240 degrees, and for a four-cylinder engine, this data needs to be output every 180 degrees.

[0084] [Speed ​​calculation unit]

[0085] Figure 7 3 is a flowchart showing the flow of processing by the rotation speed calculation unit 202 a .

[0086] The speed calculation unit 202a calculates the engine speed (ω) = Δθ / Δt [rad / s] based on the time interval Δt between the signal teeth 26a and the angular interval Δθ between the signal teeth 26a calculated by the crank angle sensor control unit 201. The engine speed is calculated for each rotation angle Δθ and is therefore the average speed between rotation angles Δθ. Based on this engine speed data, time series data of the cycle-averaged engine speed is calculated (S11). This is done to prevent errors in the engine speed from adversely affecting the estimated combustion state.

[0087] For the specific calculation method of the periodic average engine speed time series data, use Figure 8 Provide explanation.

[0088] The rotational speed calculation unit 202a imports data on the time interval Δt between signal teeth 26a, obtained by the crank angle sensor control unit 201 at each constant crank angle Δθ, as time-series data for one cycle of the engine 1 (a period of 720° crank angle). For example, if Δθ = 10°, the rotational speed calculation unit 202a imports time-series data for a total of 72 time intervals Δt, spanning crank angles from 10° to 720°. The rotational speed calculation unit 202a then converts the imported time-series data for the time intervals Δt into engine speed using the following engine speed calculation formula. Figure 8 The left diagram of shows an example of the time series data of the engine speed for each cycle obtained in this way.

[0089] The speed data of each cycle is introduced repeatedly for a predetermined number of cycles N (e.g., 100 cycles), and the time series data of the cycle-averaged engine speed is obtained using formula (1). By averaging the engine speed data at each discrete point for a predetermined number of cycles N, the time series data of the engine speed after removing the cycle error can be obtained ( Figure 8 (right image).

[0090] [Mathematical formula 1]

[0091]

[0092] ω: rotational speed

[0093] θ: crank angle

[0094] N: The number of cycles of the object to be averaged

[0095] i: cycle number

[0096] return Figure 7 , the process of the processing performed by the speed calculation unit 202a is further described. Next, the speed calculation unit 202a obtains the time series data of the engine speed after removing the high-order harmonic components from the time series data of the period-averaged engine speed (S12). After the processing of this step is completed, the call is returned to Figure 7 The processing preceding the rotation speed calculation processing is shown.

[0097] This harmonic removal process is performed to remove fluctuations unrelated to combustion from the engine speed. Examples of such fluctuations include rotational fluctuations caused by mechanical jitter in the speed-increasing gear 2 between the engine 1 and the induction generator 3, and electrical noise contained in the signal from the crank angle sensor 11. These fluctuations generally have shorter cycles than the engine rotation fluctuations caused by combustion torque, and therefore can be eliminated by removing harmonic components from the speed data. Removing these fluctuations unrelated to combustion from the speed data improves the accuracy of combustion state estimation based on engine rotation fluctuations.

[0098] To remove higher harmonic components from the speed data, the speed calculation unit 202a reconstructs the time-series data of the engine speed using the Fourier series expansion shown in equation (2). In the Fourier series expansion, the original function is reconstructed by adding sinusoidal functions of different frequencies. In equation (2), k is the degree of the sinusoidal function; the larger the k, the higher the frequency of the sinusoidal function. Therefore, when reconstructing the time-series data of the engine speed using the Fourier series expansion, if the addition of the sinusoidal functions is terminated at an appropriate degree, frequency components higher than that degree can be removed from the original data.

[0099] [Mathematical formula 2]

[0100]

[0101]

[0102]

[0103] ω(θ) AVE : The original cycle average speed

[0104] ω(θ)': reconstructed period-averaged rotational speed

[0105] k: the degree of the trigonometric function

[0106] θ: crank angle

[0107] Θ: period

[0108] In a general four-cylinder four-stroke gasoline engine, the cutoff number n of the sine function used to remove higher harmonic components not related to combustion from the speed data is preferably about 3 to 5. However, it is believed that the appropriate cutoff number n varies depending on the structure and operating conditions of the engine. For example, when the number of engine cylinders increases, the frequency of engine rotation changes caused by the combustion torque becomes higher, so in order to properly reconstruct the changing component, the cutoff number should be further increased. In addition, when the engine speed becomes faster, the frequency of engine rotation changes caused by the combustion torque also becomes higher, so the cutoff number should be further increased. Therefore, when the cutoff number n of the sine function is changed based on the engine speed, the estimation accuracy of the combustion state based on the engine rotation change can be improved in a wider operating range.

[0109] As described above, the rotation speed calculation unit 202a calculates the crank speed based on the time interval Δt between the signal teeth 26a obtained by the crank angle sensor control unit 201. The crank speed is calculated by performing a finite number of Fourier series expansions on the time series values ​​of the rotation speed. The cutoff number of the Fourier series expansion is preferably varied based on the crank speed.

[0110] Furthermore, the extreme value timing calculation unit 202b divides the crank speed time-series value period within the crank angle period of 720° by the number of cylinders and assigns the crank speed time-series value for the period including compression top dead center of each cylinder as the crank speed time-series value for that cylinder. Furthermore, the extreme value timing calculation unit 202b preferably calculates the crank speed extreme value timing for each cylinder based on the crank speed time-series value assigned to each cylinder. Furthermore, the extreme value timing calculation unit 202b preferably approximates the crank speed time-series value using a continuous function based on the discrete crank speed time-series values ​​and calculates the crank speed extreme value timing using this continuous function.

[0111] [Extreme value timing calculation unit]

[0112] Next, the processing of the extreme value timing calculation unit 202 b in the controller 12 will be described.

[0113] Figure 9 This is a flowchart showing the flow of processing by the extreme value timing calculation unit 202b.

[0114] The extreme value timing calculation unit 202b converts the time series data of the engine speed over the entire engine cycle (crank angle 0 to 720 degrees) into a local crank angle synchronized with the cycle of each engine cylinder (S21). Next, the local crank angle at which the engine speed reaches its maximum (or minimum) is calculated based on the time series data of the engine speed converted into local crank angles (S22).

[0115] [Local crank angle conversion processing]

[0116] Next, the local crank angle conversion process (S21) in the rotation speed calculation unit 202a is performed using Figures 10 to 12 Provide explanation.

[0117] Figure 10 This figure shows the sequence of strokes in a three-cylinder, four-stroke engine. A four-stroke engine performs the four strokes of intake, compression, expansion, and exhaust sequentially. In a three-cylinder engine, the strokes between cylinders are offset by 240° crank angle. Assuming that engine 1 ignites the second, first, and third cylinders in this order, the stroke of the first cylinder lags behind the stroke of the second cylinder by 240°, and the stroke of the third cylinder lags behind the stroke of the first cylinder by 240°.

[0118] The crank speed strongly reflects the combustion state near compression top dead center (CTDC) of each cylinder, where the in-cylinder pressure is highest. Therefore, in step S21, the speed data for the entire cycle (crank angles 0-720°) is segmented into 240° crank angle intervals centered around the CTDC of each cylinder. Each window is then assigned the speed data for the cylinder that includes the CTDC within the window.

[0119] [Window setting example]

[0120] Figure 11 This example uses a 240° window centered around the compression top dead center (CTDC) of each cylinder for the engine speed time series data. The range from 0 to 240° crank angle includes the CTDC of the third cylinder, so it is assigned to the third cylinder window. Similarly, the range from 240 to 480° crank angle is assigned to the second cylinder window, and the range from 480 to 720° crank angle is assigned to the first cylinder window.

[0121] In this way, when windows are assigned to each cylinder, the speed data in the third cylinder window more strongly reflects the combustion state of the third cylinder than the speed data in the other cylinder windows. Similarly, the speed data in the second cylinder window more strongly reflects the combustion state of the second cylinder than the speed data in the other cylinder windows, and the speed data in the first cylinder window more strongly reflects the combustion state of the first cylinder than the speed data in the other cylinder windows. Thus, by using the speed data in each window, the combustion state can be estimated for each cylinder.

[0122] Furthermore, in process S21 , the rotation speed data of each window is converted into a local crank angle based on the compression top dead center of each cylinder. Figure 12An example of converting the rotational speed data for each window into local crank angles is shown. In this example, the rotational speed time series data is redefined using local crank angles ranging from -120° to 120°, with compression top dead center (CTDC) of each cylinder set to zero. In process S21, time series data of the rotational speed converted into local crank angles is generated for all cylinder windows and passed to process S22.

[0123] Next, in step S22 , the timing (timing) at which the rotation speed is maximum or the timing (timing) at which the rotation speed is minimum is calculated based on the time series data of the rotation speed converted into the local crank angle.

[0124] [Maximum rotation speed]

[0125] exist Figure 13 The calculation method of the maximum timing of the rotation speed in the process S22 is shown in FIG.

[0126] Since the speed time series data is discrete point data, the maximum timing of the speed in the discrete point data is different from the actual speed ( Figure 13 The maximum timing θ of the rotation speed indicated by the dotted line max Therefore, in processing S22, the rotation speed is approximated by a polynomial based on the discrete point data, and the maximum timing θ of the rotation speed is obtained based on the approximation. max .

[0127] Therefore, in the process S22, first, the data point n with the maximum rotation speed is found from the time series data of the rotation speed as discrete point data. Figure 13 An example of time series data with an upward convex characteristic is shown in FIG. Then, the local crank angle θ at the data point n is extracted. n and speed ω n , the local crank angle θ at the data point one sample before data point n n-1 and speed ω n-1 , the local crank angle θ at the data point after one sampling of data point n n+1 and speed ω n+1 .

[0128] Furthermore, in step S22, the rotational speed ω is approximated by the quadratic function of the local crank angle θ, that is, equation (3). Here, a, b, and c are constants. In step S22, by solving equation (3) and substituting θ n 、ω n ,θ n-1 、ω n-1 ,θ n+1 、ω n+1 Solve the three linear equations obtained and find the constants a, b, and c.

[0129] [Mathematical formula 3]

[0130] ω=aθ2 +bθ+c……(3)

[0131] The differential value of equation (3) is zero at the point where the rotation speed reaches its extreme value. Therefore, in step S22, the local crank angle (maximum speed timing) θ where the rotation speed is maximum is obtained using equation (4): max Use the same process to find the maximum timing θ for each cylinder max , and transmit them to the combustion phase calculation unit 202c.

[0132] [Formula 4]

[0133]

[0134]

[0135] [Minimum rotation speed timing]

[0136] In addition, in step S22, the minimum timing θ of the rotation speed is obtained. mix In the case of , the maximum timing of the rotation speed is also calculated using θ max The same method is used to find the answer for the case of .

[0137] exist Figure 14 , a calculation method of the minimum timing of the rotation speed in process S22 is shown.

[0138] In the process S22 , first, the data point n with the minimum rotation speed is found from the time series data of the rotation speed as discrete point data. Figure 14 An example of time series data with a downward convex characteristic is shown in FIG. Then, the local crank angle θ at the data point n is extracted. n and speed ω n , the local crank angle θ at the data point one sample before data point n n-1 and speed ω n-1 , the local crank angle θ at the data point after one sampling of data point n n+1 and speed ω n+1 .

[0139] Then, in step S22, these values ​​are used to determine the constants a, b, and c of the quadratic function according to equation (3), and the local crank angle (minimum speed timing) θ at which the rotation speed is minimum is determined according to equation (4). min In addition, the same process is used to find the minimum timing θ for each cylinder. min , and transmit them to the combustion phase calculation unit 202c.

[0140] In the above embodiment, the rotational speed ω is approximated by a quadratic function of the local crank angle θ, but the present invention is not limited thereto. For example, the rotational speed ω may be approximated by various continuous functions such as a cubic function or a sine function of the local crank angle θ.

[0141] [Combustion phase calculation unit]

[0142] Next, the combustion phase calculation method of the combustion phase calculation unit 202c in the controller 12 is used. Figures 15 to 18 Provide explanation.

[0143] [Calculation method of the combustion center of gravity position using the timing of maximum engine speed]

[0144] Figure 15 is the maximum timing of the engine speed θ max A graph showing the correlation with the combustion center position MFB50. Here, the mass fraction burned (MFB) is the ratio of the burned mass to the total mass of the mixed gas. The combustion center position MFB50 represents the crank angle at which the mass fraction burned is 50%. The timing of the maximum engine speed θ max There is a strong correlation between the position of the combustion center of gravity MFB50, such as Figure 15 As shown in FIG, the relationship between the two is approximately linear. The reason for this is explained below.

[0145] The time variation of the engine speed can be expressed by the motion equation of the rotating body shown in equation (5). Here, T C is the combustion torque, T L is the load torque, (T C -T L ) is the inertia torque. In addition, I is the inertia moment and t is time.

[0146] [Formula 5]

[0147]

[0148] From formula (5), we can know that the rotational acceleration dω / dt and the combustion torque T C The rotational acceleration dω / dt is directly proportional to the combustion torque. As the combustion center of gravity changes, so does the rotational acceleration dω / dt. For example, as the combustion center of gravity position is delayed, the timing of combustion torque generation also delays, and synchronously, the timing of maximum rotational acceleration also delays. Consequently, the timing of maximum rotational acceleration is strongly correlated with the combustion center of gravity position.

[0149] On the other hand, the load torque T LWhen the change in is small, the time variation of the combustion torque becomes roughly sinusoidal. This is because the arm length of the crank, which determines the size of the combustion torque, changes in a sinusoidal manner as the crankshaft rotates. When the rotational acceleration is sinusoidal, the rotational speed obtained by integrating the rotational acceleration is also sinusoidal, and the time variation waveform of the rotational acceleration and the time variation waveform of the rotational speed maintain a certain phase difference. Therefore, the phase difference between the maximum timing of the rotational acceleration and the maximum timing of the rotational speed is also certain, and the combustion center of gravity position has a strong correlation not only with the maximum timing of the rotational acceleration, but also with the maximum timing of the rotational speed. That is, in this embodiment, it is preferred that the waveform representing the crank speed of the vertical axis relative to the crank angle of the horizontal axis is sinusoidal.

[0150] The maximum timing θ of the engine speed is obtained in advance by calibration, etc. max The correlation line with the combustion center of gravity position MFB50 is stored in the ROM (storage unit 123) of the controller 12 in the form of a correlation equation or a reference table. The combustion phase calculation unit 202c calculates the maximum timing θ of the current engine speed transmitted from the extreme timing calculation unit 202b. max_current ,use Figure 15 The maximum timing of the engine speed is shown as θ max The correlation line with the combustion center of gravity position MFB50 is used to calculate the current combustion center of gravity position MFB50_ current For each cylinder, use the same process to find the current combustion center of gravity position MFB50_ current , and transmit them to the engine control unit 203 of the controller 12.

[0151] [Calculation method of the combustion center of gravity position using the timing of minimum engine speed]

[0152] In addition, the minimum timing θ of the engine speed is used min , can also be compared with the maximum timing of engine speed θ max The combustion center of gravity position is calculated in the same way as in the case of .

[0153] Figure 16 is the minimum timing of the engine speed θ min The graph showing the correlation with the combustion gravity center position MFB50. The minimum timing of the engine speed θ min There is a strong correlation between the position of the combustion center of gravity MFB50, such as Figure 16 As shown in FIG, the relationship between the two is approximately linear. The reason for this is explained below.

[0154] As mentioned above, the load torque T LWhen the change in is small, the temporal variation in engine speed is sinusoidal. Therefore, there is a roughly constant phase difference between the timing of maximum and minimum speed. Consequently, the combustion center of gravity position is strongly correlated not only with the timing of maximum speed but also with the timing of minimum speed.

[0155] The minimum timing θ of the engine speed is obtained in advance by calibration, etc. min The correlation line with the combustion center of gravity position MFB50 is stored in the ROM (storage unit 123) of the controller 12 in the form of a correlation equation or a reference table. The combustion phase calculation unit 202c calculates the minimum timing θ based on the current engine speed transmitted from the extreme timing calculation unit 202b. min_current ,use Figure 16 The minimum timing of the engine speed is shown as θ min The correlation line with the combustion center of gravity position MFB50 is used to calculate the current combustion center of gravity position MFB50_ current The same process is used for each cylinder to calculate the current combustion center position MFB50_ current , and transmit them to the engine control unit 203 of the controller 12.

[0156] [Calculation method of the initial combustion position using the timing of maximum engine speed]

[0157] In addition, the maximum timing of the engine speed θ is used max , the initial combustion position MFB10 (burned mass fraction 10% position) can also be obtained.

[0158] Figure 17 is the maximum timing of the engine speed θ max The graph of the correlation with the initial combustion position MFB10. The maximum timing of the engine speed θ max There is a strong correlation with the initial combustion position MFB10, such as Figure 17 The relationship between the two is roughly linear. This is because when the initial combustion position changes, the timing of the combustion torque changes accordingly. Therefore, if the maximum timing of the engine speed θ is determined in advance by calibration, max The correlation line with the initial combustion position MFB10 can be calculated based on the maximum timing θ of the current engine speed. max_current use Figure 17 The maximum timing of the engine speed is shown as θ max Correlation line with the initial combustion position MFB10, calculate the current initial combustion position MFB10 current In addition, by current Subtract the current ignition timing θ ig_current , the current initial combustion period Δθ can also be calculated ig10_current .

[0159] The combustion phase calculation unit 202c calculates the current combustion center of gravity position MFB10 for each cylinder using the same process. current , initial combustion period Δθ ig10_current , and transmit them to the engine control unit 203 of the controller 12.

[0160] [Calculation method of the combustion center of gravity position using the timing of minimum engine speed]

[0161] Furthermore, the minimum timing θ of the engine speed is used min , the initial combustion position MFB10 can also be obtained.

[0162] Figure 18 is the minimum timing of the engine speed θ min The graph of the correlation with the initial combustion position MFB10. The minimum timing of the engine speed θ min There is a strong correlation with the initial combustion position MFB10, such as Figure 18 The relationship between the two is roughly linear. Therefore, if the minimum timing θ of the engine speed is obtained in advance by calibration, min The correlation line with the initial combustion position MFB10 can be calculated based on the minimum timing θ of the current engine speed. min_current use Figure 18 The minimum timing of the engine speed is shown as θ min The correlation line with the initial combustion position MFB10 is used to find the current initial combustion position MFB10_ current In addition, by MFB10_ current Subtract the current ignition timing θ ig_current , the current initial combustion period Δθ can also be calculated ig10_current .

[0163] The combustion phase calculation unit 202c calculates the current combustion center of gravity position MFB10_ for each cylinder using the same process. current , initial combustion period Δθ ig10_current , and transmit them to the engine control unit 203 of the controller 12.

[0164] As described above, the internal combustion engine control device (controller 12) of the present embodiment is configured to include a crank angle sensor control unit 201 that calculates the time interval Δt of the signal tooth 26a based on the voltage signal 26b of the crank angle sensor 11 and buffers it, a speed calculation unit 202a that calculates the crank speed of the internal combustion engine (engine 1), an extreme timing calculation unit 202b that calculates the extreme timing of the crank speed calculated by the speed calculation unit 202a, and a combustion state estimation unit (combustion phase calculation unit 202c) that estimates the combustion state based on the extreme timing of the crank speed calculated by the extreme timing calculation unit 202b.

[0165] [Engine control by the engine control unit]

[0166] Next, the control of the engine 1 by the engine control unit 203 will be described. Hereinafter, the ignition timing control and the EGR control will be described as examples.

[0167] [Ignition timing control]

[0168] To improve the engine's thermal efficiency, it's necessary to appropriately control the combustion phase. If the combustion phase is too early, the work required to compress the gas during the compression stroke increases, leading to increased losses. Conversely, if the combustion phase is too late, the exhaust temperature rises, increasing exhaust-related heat losses. The combustion phase with the highest thermal efficiency is determined by the combustion center of gravity position MFB50. Therefore, controlling the ignition timing to achieve a predetermined value for the combustion center of gravity position MFB50 can improve the engine's thermal efficiency. Therefore, the engine control unit 203 implements drive control of the engine 1 based on the combustion center of gravity position MFB50.

[0169] Figure 19 1 is a control block diagram of the ignition timing in the controller 12. The reference numerals attached to the processing modules represent the main body of the processing of the processing modules (refer to Figure 4 ).

[0170] In the control of the ignition timing in the controller 12, the current MFB50_ is calculated by the combustion phase calculation unit 202c. current The engine control unit 203 calculates the ignition timing based on the deviation from the target MFB50, and sends an ignition signal to the engine 1 at the calculated ignition timing. The engine control unit 203 is composed of a PID controller so that MFB50_ current The ignition timing is adjusted so that the deviation from the target MFB50 is reduced. More specifically, MFB50_ current If the ignition timing is later than the target MFB50, the ignition timing is advanced to advance the combustion phase. current When it is earlier than the target MFB50, the ignition timing is retarded in order to retard the combustion phase.

[0171] The internal combustion engine control device (controller 12) of this embodiment includes an engine control unit 203 that performs combustion control of the internal combustion engine (engine 1) based on the combustion state estimated by the combustion state estimation unit (combustion phase calculation unit 202c). Furthermore, it is preferable that the internal combustion engine (engine 1) drives the induction generator 3 of the series hybrid system.

[0172] Furthermore, the combustion state estimation unit (combustion phase calculation unit 202c) of the internal combustion engine control device (controller 12) estimates the combustion phase at which the burned mass fraction of the internal combustion engine (engine 1) reaches a set value based on the timing at which the crank speed reaches a maximum or minimum. The engine control unit 203 controls the combustion of the internal combustion engine (engine 1) so that the estimated combustion phase reaches the set phase. The engine control unit 203 controls the ignition timing of the internal combustion engine (engine 1) so that the estimated combustion phase reaches the set phase.

[0173] Specifically, the combustion state estimation unit (combustion phase calculation unit 202c) calculates the combustion phase (combustion center of gravity position MFB50) that results in a mass burn fraction of 50% and the combustion phase (initial combustion position MFB10) that results in a mass burn fraction of 10%. The engine control unit 203 then preferably controls the ignition timing so that the estimated combustion phase (combustion center of gravity position MFB50) is, for example, 8° to 15° after top dead center. Furthermore, the engine control unit 203 preferably controls the ignition timing so that the estimated combustion phase (initial combustion position MFB10) is, for example, within 15° after ignition.

[0174] Specifically, the engine control unit 203 controls the EGR valve opening of the internal combustion engine (engine 1) so that the estimated combustion phase (initial combustion position MFB10) reaches a set phase (e.g., within 15 degrees after ignition). If the estimated combustion phase (initial combustion phase MFB10) is later than the set phase (e.g., within 15 degrees after ignition), the engine control unit 203 controls the EGR valve opening of the internal combustion engine (engine 1) toward the closing direction.

[0175] When the estimated combustion phase (combustion center of gravity position MFB50, initial combustion position MFB10) is later than the above-set phase, the engine control unit 203 controls the internal combustion engine (engine 1) to advance the ignition timing. Conversely, when the estimated combustion phase (combustion center of gravity position MFB50, initial combustion position MFB10) is earlier than the above-set phase, the engine control unit 203 controls the internal combustion engine (engine 1) to retard the ignition timing.

[0176] In addition, the combustion phase calculation unit 202c obtains the current combustion center of gravity position MFB50_ for each cylinder.current Therefore, it is preferred to implement the MFB50_ current In a multi-cylinder engine, there is a risk that the combustion phase may differ between cylinders due to errors in the amount of intake air, etc. However, by using the MFB50_ current By controlling the ignition timing for each cylinder, the combustion phase of each cylinder can be optimized, which can improve thermal efficiency and emission performance. current Calculate the average MFB50 of the cylinder current In this case, the ignition timing is the same for all cylinders, and while there is a risk of reduced thermal efficiency and emissions compared to controlling the ignition timing for each cylinder, there is an advantage of simplified control.

[0177] [EGR control]

[0178] Next, other engine controls performed by the engine control unit 203 will be described.

[0179] In order to improve the thermal efficiency of the engine, exhaust gas recirculation (EGR) control is generally performed to mix exhaust gas into the engine's intake air. When EGR is used, the amount of intake gas in the cylinder increases, so it is possible to reduce pumping losses at partial loads. In addition, the combustion temperature is reduced due to the inactive gas, so cooling losses can be reduced. In addition, EGR is also effective in suppressing knocking at high loads. Generally speaking, the greater the proportion of EGR in the intake gas (EGR rate), the higher the effect of EGR. On the other hand, when the EGR rate increases, combustion becomes unstable, and concerns about misfires and increased emissions increase.

[0180] exist Figure 20 The initial combustion period Δθ is shown in ig10 An example of the relationship with the periodic variation rate of combustion torque.

[0181] Initial combustion period Δθ ig10 Indicates the ignition susceptibility of the mixed gas, Δθ ig10 The larger the value, the lower the ignition quality of the mixed gas. ig10 When it increases, misfire is more likely to occur and the periodic fluctuation of combustion torque increases. ig10 When it exceeds a specified value, the misfire period increases rapidly, and the increase in torque fluctuation accelerates.

[0182] Thus, the combustion instability caused by EGR is determined by the initial combustion period Δθ ig10 Therefore, the initial combustion period Δθ is set to ig10By controlling the EGR rate to a predetermined value, it is possible to prevent misfire and emission degradation while improving the thermal efficiency of the engine. ig10 Engine control.

[0183] The combustion state estimation unit of the control unit 122 estimates the initial combustion period Δθ of the internal combustion engine (engine 1) based on the timing when the crank speed is maximum or minimum. ig10 The engine control unit 203 sets the estimated initial combustion period Δθ ig10 The combustion control of the internal combustion engine (engine 1) is performed so as to set the initial combustion period. Specifically, the engine control unit 203 calculates the initial combustion period Δθ. ig10 If the estimated initial combustion period Δθ is longer than the set initial combustion period, the EGR valve opening of the internal combustion engine (engine 1) is controlled in the closing direction. ig10 If the opening of the EGR valve of the internal combustion engine (engine 1) is shorter than the set initial combustion period, the engine control unit 203 controls the opening of the EGR valve of the internal combustion engine (engine 1) toward the closing direction.

[0184] Figure 21 1 is a control block diagram of EGR in the controller 12. The reference numerals attached to each processing module represent the main body of the processing of each processing module (refer to Figure 4 ).

[0185] In the EGR control by the controller 12, the current initial combustion period Δθ calculated by the combustion phase calculation unit 202c is used. ig10_current and target Δθ ig10 The engine control unit 203 calculates the EGR valve opening and operates the engine 1 according to the calculated EGR valve opening. ig10_current , from the initial combustion period Δθ of each cylinder ig10_current Select the largest Δθ ig10_current , and EGR control is performed based on it.

[0186] Here, the largest Δθ is selected ig10_current , because as mentioned above, the combustion stability has a relationship with the initial combustion period Δθ ig10 The tendency of rapid deterioration corresponding to the increase of ig10_current The engine control unit 203 controls the EGR valve opening of the internal combustion engine (engine 1) so that the maximum initial combustion period among the initial combustion periods of each cylinder becomes the set phase.

[0187] The engine control unit 203 is composed of a PID controller so that Δθ ig10_currentand target Δθ ig10 More specifically, the EGR valve opening is adjusted in such a way that the deviation is reduced. ig10_current Greater than target Δθ ig10 In the case of , the EGR valve opening is reduced to reduce the EGR rate. ig10_current Less than target Δθ ig10 In the case of , the EGR valve opening is increased to increase the EGR rate.

[0188] By using the current initial combustion period Δθ ig10_current By controlling EGR, the EGR rate can be maximized without affecting combustion stability, thereby improving the efficiency of the engine 1 .

[0189] Furthermore, in this embodiment, the combustion phase is determined based on the timing of the maximum engine speed. This eliminates the need for differential processing to determine the engine's rotational acceleration, as is common in conventional techniques. This offers the advantage of being less susceptible to external interference such as noise. Furthermore, the absence of differential processing simplifies the structure of the controller 12, reducing software development effort and circuit costs.

[0190] Thus, this embodiment includes an engine control unit (engine control unit 203) that controls the internal combustion engine (engine 1) based on the combustion state detected by the combustion detection control unit (combustion detection control unit 202). This engine control unit (engine control unit 203) has an ignition control function that controls ignition based on the combustion state detected by the combustion detection control unit (combustion detection control unit 202), and an exhaust gas recirculation control function that controls exhaust gas recirculation (EGR) by recirculating part of the exhaust gas to the intake side based on the combustion state detected by the combustion detection control unit (combustion detection control unit 202).

[0191] [Methods to improve the reliability of combustion detection control]

[0192] Next, a method for improving the reliability of the combustion detection control unit 202 will be described.

[0193] Figure 22 This is a timing chart showing data transmission by a conventional crank angle sensor control unit when noise is mixed.

[0194] Figure 23 1 is a timing chart showing data transmission by the crank angle sensor control unit 201 according to one embodiment of the present invention when noise is mixed.

[0195] The crank plate 26 typically includes a tooth notch 301 (a portion without a signal tooth (tooth notch portion)) or similar structure to periodically correct its absolute position (rotational position) for external interference such as noise and missing teeth (missing signals). Specifically, the absolute position of the tooth notch 301 is hardware-set to a specific position during assembly of the crank plate 26. This prevents the effects of noise or missing teeth from entering the signal during a given cycle from continuing into the next cycle. Consequently, a method is known for diagnosing signal validity (reliability) by using the position immediately after the tooth notch 301 (the first tooth) or the second tooth 302 as a reference position and determining whether the number of signals between these reference positions is within a specified value.

[0196] Figure 22 , a situation where noise 303 is mixed in between tooth gap 301 and the timing of transmitting buffered data at time interval Δt is shown. In this situation, after tooth gap 301 or during diagnosis or calibration using second tooth 302, it is determined that there is no problem with the signal data.

[0197] On the other hand, because the data is actually being sent Figure 22 Since noise is mixed in at the transmission timing on the right, data mixed with noise will be output to combustion detection control unit 202. In other words, combustion detection control unit 202 will be executed based on data mixed with noise and low accuracy. This may not only fail to achieve the improvement in thermal efficiency that is the purpose of this engine control, but may even reduce thermal efficiency.

[0198] Therefore, in the invention of this embodiment, if Figure 23 As shown, the timing for transmitting the buffered information for the time interval Δt is set to after the tooth gap (the first tooth) or the second tooth. This is equivalent to synchronizing the diagnosis timing with the transmission timing, transmitting the buffered data immediately after diagnosis. By transmitting data at this timing, as described later, the buffered information for the time interval Δt can be transmitted with high reliability.

[0199] Here, a method for detecting the tooth gap 301 will be briefly described. The Δt calculation unit 501 (refer to Figure 24 ) calculates the time interval Δt between adjacent ON signals of the voltage signal 26b at any time to detect the tooth gap 301. For example, Figure 23 In the example, the time interval Δt between ON signals s1 and s2 and the time interval Δt between ON signals s2 and s3 are compared. Since the time interval Δt between ON signals s2 and s3 is longer, it is detected that there is a tooth gap 301 between ON signals s2 and s3. Furthermore, by comparing the time interval between ON signals s2 and s3 and the time interval between ON signals s3 and s4, it is also possible to detect that there is a tooth gap 301 between ON signals s2 and s3.

[0200] The timing for transmitting buffer information is not limited to the timing described above. Buffer information can be transmitted upon detection of a tooth notch 301, within a period corresponding to a predetermined number of signal teeth from the time the notch 301 is detected. The period corresponding to a predetermined number of signal teeth from the time the notch 301 is detected can also be set to the third or fourth tooth, but the shorter the period, the better. Preferably, the period is after the detection of the notch 301 (the first tooth) or the second tooth.

[0201] As described above, the crank angle sensor control device (crank angle sensor control unit 201) of the present embodiment is configured to include a buffer unit (buffer processing unit 502) for storing signal information (voltage signal 26b) of a specified period of the crank angle sensor (11) for detecting signal teeth (26a) formed on the crank disk (26); and an output processing unit (output processing unit 503) for outputting the signal information (buffer data 26c) stored in the buffer unit (buffer processing unit 502) during the period from the detection of the tooth notch position to the detection of the specified number of signal teeth, based on the detection of the tooth notch position (tooth notch 301) on the crank disk as the reference position of the crank disk.

[0202] In addition, the internal combustion engine control device of this embodiment includes a crank angle sensor control unit (crank angle sensor control unit 201) and a combustion detection control unit (combustion detection control unit 202) that receives signal information (buffered data 26c) from the crank angle sensor control unit and performs processing related to combustion detection.

[0203] In addition, the crank angle sensor control device (crank angle sensor control unit 201) of this embodiment is configured to output the signal information (buffer data 26c) stored in the buffer unit (buffer processing unit 502) when the output processing unit (output processing unit 503) inputs the signal information (voltage signal 26b) of the first tooth or the second tooth (302) from the tooth notch position (tooth notch 301) on the crank disk which is the reference position of the crank disk.

[0204] According to the present embodiment constructed as described above, for an internal combustion engine control device (controller 12) that detects combustion characteristics and controls the engine with a robust and simple structure, even if external interference such as noise is generated in the signal information of the crank angle sensor (11), the accuracy of the combustion state estimation can be kept constant or kept to a minimum. In other words, the reliability of the signal information of the crank angle sensor (11) can be improved. As a result, a simple, low-cost internal combustion engine control device that can robustly estimate the combustion state can be provided. In addition, as a result, the effect of improving thermal efficiency can be stably achieved.

[0205] (Reliability judgment results (normal / abnormal) and buffer data)

[0206] Then, in Figure 24 2 shows a control block diagram of the crank angle sensor control unit 201 according to one embodiment of the present invention. Conventionally, buffered information at time interval Δt is sent directly to the combustion detection control unit 202. However, the present invention is characterized in that reliability determination processing is performed after detecting the tooth notch 301 and before data transmission.

[0207] like Figure 24 As shown, the crank angle sensor control unit 201 of this embodiment includes a Δt calculation unit 501 , a buffer processing unit 502 , a reliability determination unit 2401 , and an output processing unit 503 .

[0208] Δt calculation unit 501 is used to calculate Figure 5 The processing module of the time interval Δt between the signal teeth 26a shown in step S1 is shown in FIG. That is, the Δt calculation unit 501 calculates the time interval Δt between the signal teeth 26a shown in step S1 based on the voltage signal 26b of the crank plate 26 detected by the crank angle sensor 11 (reference signal 26b). Figure 6 ), calculate the time interval Δt between the signal teeth 26a.

[0209] The buffer processing unit 502 is used to perform Figure 5 The buffer processing module shown in step S2 of FIG. Specifically, the buffer processing unit 502 performs a buffering process for storing information corresponding to a predetermined time interval Δt between each signal tooth 26 a. The buffer processing unit 502 outputs the buffered information to the reliability determination unit 2401 .

[0210] Reliability determination unit 2401 is a processing module that determines the output signal of crank angle sensor 11 between tooth notch positions (tooth notch 301) on crank plate 26 based on the output signal (voltage signal 26b) of crank angle sensor 11. Reliability determination unit 2401 outputs its reliability determination result to output processing unit 503. Reliability determination unit 2401 also outputs buffer information input from buffer processing unit 502 to output processing unit 503. Alternatively, a configuration in which reliability determination unit 2401 detects tooth notch positions may be employed.

[0211] The output processing unit 503 is to perform Figure 5 The output processing module shown in step S3 is described below. Specifically, the output processing unit 503 generates transmission data including buffer information (buffered data 26c) regarding the buffered time interval Δt, and outputs this transmission data to the rotation speed calculation unit 202a of the combustion detection control unit 202 via the interface 204. Furthermore, the reliability determination result 305 from the reliability determination unit 2401 is output to the rotation speed calculation unit 202a along with the buffered data 26c. The output processing unit 503 and the interface 204 may also be referred to as an interface.

[0212] As a method for determining reliability, for example, there is a method of comparing the number of ON signal inputs of the voltage signal 26b between the tooth gaps 301 (in one cycle) with a threshold value. Here, one cycle is one rotation of the crank plate 26. Figure 24 In the example, after the reliability determination process, the buffered data 26c of the time interval Δt is sent together with the reliability determination result 305. Figure 23 The preferred embodiment is after the tooth gap 301 or the second tooth is detected. Figure 23 , an example is shown in which the transmission timing is set to the first tooth after tooth notch 301 is detected. Regardless of whether the result is normal or abnormal, reliability determination result 305 is transmitted along with buffered data 26c. Thus, if the determination result is "normal," buffered data 26c can be used directly for combustion detection control. On the other hand, if the determination result is "abnormal," combustion detection control can refer to this determination result and perform appropriate processing for the abnormality.

[0213] As described above, the crank angle sensor control device (crank angle sensor control unit 201) of this embodiment includes a determination unit (reliability determination unit 2401) for determining abnormality of signal information (voltage signal 26b) of the crank angle sensor between tooth notch positions (tooth notch 301) on a crank plate (26) based on the number of signals of the crank angle sensor (11) between tooth notch positions. The output processing unit (output processing unit 503) is configured to output the signal information (buffer data 26c) stored in the output buffer unit (buffer processing unit 502) together with the determination result of the determination unit (reliability determination unit 2401).

[0214] (Reliability judgment result (abnormal) and output stop or specified value)

[0215] Figure 25 This is a control block diagram (1) showing the crank angle sensor control unit 201 when the reliability determination result 305 is determined to be abnormal according to one embodiment of the present invention.

[0216] As mentioned above, Figure 24 In FIG. 1 , an example is shown in which the buffer data 26c (actual value) is sent even when it is determined to be abnormal. On the other hand, Figure 25 In the case of an abnormality, the reliability determination result 305 is transmitted and the buffered data 26c is not transmitted, or a predetermined value 306 is transmitted instead of the buffered data 26c. The predetermined value 306 is, for example, a value representing the number of ON signals in the voltage signal 26b. By stopping the transmission of the buffered data 26c, the combustion detection control unit 202 can be prevented from learning using low-accuracy buffered data 26c.

[0217] Furthermore, it is possible to transmit a value as the prescribed value 306 that clearly identifies an abnormality in the combustion detection control unit 202, or a value that does not affect combustion detection control. Transmitting the prescribed value 306 can prevent data discontinuity compared to stopping transmission of the buffered data 26c. Therefore, this can be advantageous depending on the combustion detection control logic. For example, it is unknown whether the combustion detection control unit 202 will detect an abnormality when no value is input to it. Therefore, to avoid a mismatch between the specifications of the combustion detection control unit 202 and the input information, a false value is transmitted to the combustion detection control unit 202.

[0218] As described above, the crank angle sensor control device (crank angle sensor control unit 201) of this embodiment includes a determination unit (reliability determination unit 2401) for determining abnormality of signal information (voltage signal 26b) of the crank angle sensor between tooth notch positions (tooth notch 301) on a crank plate (26) based on the number of signals of the crank angle sensor (11) between tooth notch positions. When the determination unit (reliability determination unit 2401) determines that the signal information is abnormal, the output processing unit (output processing unit 503) outputs the determination result of the determination unit and stops outputting the signal information (buffered data 26c) stored in the buffer unit (buffer processing unit 502) or outputs a predetermined value instead of the signal information (buffered data 26c).

[0219] In addition, in this embodiment, when the judgment unit (reliability judgment unit 2401) judges that the signal information is abnormal, the buffer unit (buffer processing unit 502) can stop storing the signal information of the crank angle sensor (11) for a predetermined period, or store a predetermined value instead of the signal information stored in the buffer unit. This can avoid buffering low-precision signal information and prevent the combustion detection control unit 202 from performing learning (combustion detection processing) using low-precision buffer data 26c.

[0220] Furthermore, in this embodiment, the combustion detection control unit (combustion detection control unit 202) may be configured to immediately stop the combustion detection process or fix the value calculated based on the combustion detection result to a predetermined value when it determines that the signal information (buffered data 26c) input from the crank angle sensor control unit (crank angle sensor control unit 201) contains an abnormality. This prevents the combustion detection control unit 202 from performing learning (combustion detection processing) using low-precision signal information (buffered data 26c).

[0221] Furthermore, this embodiment includes an engine control unit (engine control unit 203) that controls the internal combustion engine (engine 1) based on the combustion state detected by the combustion detection control unit (combustion detection control unit 202). The engine control unit (engine control unit 203) is configured to immediately stop combustion detection control if it determines that the signal information (buffered data 26c) input from the crank angle sensor control unit (crank angle sensor control unit 201) contains an abnormality. This prevents the engine control unit from using inaccurate buffered data 26c for driving control of the engine 1.

[0222] (Reliability judgment results (abnormal) and correction values)

[0223] Figure 26 This is a control block diagram (2) of the crank angle sensor control unit 201 when the reliability determination result 305 is determined to be abnormal according to one embodiment of the present invention.

[0224] Figure 26 The characteristic of the present invention is that when an abnormality is determined, a reliability determination result 305 is transmitted. Furthermore, rather than transmitting the buffered data 26c (actually measured values), a correction value 307 of the buffered data 26c is transmitted. For example, correction value 307 can be calculated by extrapolating the buffered data 26c from the period immediately preceding the abnormality determination. This allows control to be performed that inherits the transition in the combustion state within the engine combustion chamber prior to the determination that the voltage signal 26b between the tooth notch positions was abnormal.

[0225] Alternatively, a method can be considered that performs corrections based on the nature of the abnormality. For example, if the abnormality is noise equivalent to one tooth, buffered data 26c with the number of signals corresponding to one tooth subtracted is transmitted. Conversely, if one tooth is missing, buffered data 26c with the number of signals corresponding to one tooth added is transmitted. This eliminates the influence of the abnormality and allows for continued high-precision combustion detection control.

[0226] While the above embodiment describes an example in which a function for coping with abnormalities is implemented in the crank angle sensor control unit 201, the combustion detection control unit 202 may also have a function for coping with abnormalities when an abnormality is determined. Specifically, it is understood that implementing a failsafe function such as stopping combustion detection or correcting by applying a predetermined value in the combustion detection control unit 202 when an abnormality is determined is also effective.

[0227] As described above, the crank angle sensor control device (crank angle sensor control unit 201) of this embodiment includes a judgment unit (reliability judgment unit 2401) for judging abnormality of signal information (voltage signal 26b) of the crank angle sensor between tooth notch positions (tooth notch 301) on a crank plate (26) based on the number of signals of the crank angle sensor (11) between tooth notch positions. When the judgment unit (reliability judgment unit 2401) judges that the signal information is abnormal, the output processing unit (output processing unit 503) outputs the judgment result of the judgment unit and outputs signal information obtained by correcting the signal information (buffer data 26c) stored in the buffer unit (buffer processing unit 502) based on the signal information of the crank angle sensor (11) input between tooth notch positions (tooth notch 301) on the crank plate (26).

[0228] In addition, in this embodiment, for example, the determination unit (reliability determination unit 2401) may calculate the signal information (buffer data 26c) stored in the buffer unit (buffer processing unit 502) by extrapolating past signal information of the crank angle sensor (11) determined to be normal. This allows the combustion detection control unit 202 to receive appropriate signal information (buffer data 26c) corrected based on past signal information (actual value), thereby achieving stable combustion detection control.

[0229] <Other>

[0230] The present invention is not limited to the above-described embodiments, and various other application examples and modified examples can be adopted without departing from the gist of the present invention described in the claims.

[0231] For example, the above-described embodiments describe the structure of the controller 12 in detail and specifically to facilitate understanding of the present invention, and are not limited to having all the described components. Furthermore, a portion of the structure of a particular embodiment can be replaced with components of another embodiment. Furthermore, components of another embodiment can be added to the structure of a particular embodiment. Furthermore, other components can be added to, replaced with, or deleted from a portion of the structure of each embodiment.

[0232] In each of the above embodiments, the internal combustion engine (engine 1) is used exclusively for power generation to drive the hybrid system's generator (induction generator 3). While the present invention is described as an example of engine control applied to a hybrid (series hybrid) vehicle whose engine is used exclusively for power generation, the present invention is not limited thereto. For example, the present invention can also be applied to hybrid vehicles whose engine is not used exclusively for power generation, and to non-hybrid vehicles whose engine serves solely as the vehicle's driving source.

[0233] However, it is preferably applied to engine control of a hybrid vehicle in which the engine is dedicated to power generation, mainly for the following three reasons: In other vehicles, the conditions that can be detected are limited, so the coverage is reduced.

[0234] (1) Hybrid vehicles used exclusively for power generation do not experience transient operation, so they are more easily detected than other vehicles.

[0235] (2) Since the engine output is used only for power generation, the road surface condition and the vibration of the drive system are reduced. In other words, the angular velocity fluctuation (noise) of the output signal of the crank angle sensor is reduced.

[0236] (3) Since the output signal of the crank angle sensor has a small pulsation component, the detectability is good.

[0237] Furthermore, the above-described structures, functions, and processing units may be partially or entirely implemented in hardware, for example, by designing them into an integrated circuit. Broadly speaking, processor devices such as FPGAs (Field Programmable Gate Arrays) and ASICs (Application Specific Integrated Circuits) may be used as hardware.

[0238] Description of Reference Numerals

[0239] 1…Engine, 3…Induction generator, 5…Battery, 7…Induction motor, 10…Knock sensor, 11…Crank angle sensor, 12…Controller, 17…Spark plug, 20…Throttle valve, 26…Crank plate, 28…EGR pipe, 29…EGR valve, 122…Control unit, 121…Input / output unit, 202a…Speed ​​calculation unit, 202b…Extreme value timing calculation unit, 202c…Combustion phase calculation unit, 122d…Signal time interval calculation unit, 203…Engine control unit, 12 3…Storage unit, 201…Crank angle sensor control unit, 202…Combustion detection control unit, 204…Interface between the crank angle sensor control unit and the combustion detection control unit, 26b…Voltage signal, 26c…Buffered data, 501…Δt calculation unit, 502…Buffer processing unit, 503…Output processing unit, 301…Tooth gap, 302…The tooth after the tooth gap or the second tooth, 303…Noise, 305…Reliability judgment result, 306…Specified value, 307…Correction value, 2401…Reliability judgment unit.

Claims

1. A crank angle sensor control device for processing a voltage signal output by a crank angle sensor disposed opposite a crank disk, wherein the crank disk includes, on its rotating circumference, a portion provided with a predetermined number of signal teeth and a tooth-notch portion provided with no signal teeth, the crank angle sensor control device comprising: a time interval calculation unit that detects, based on a voltage signal outputted from the crank angle sensor, that a portion provided with the signal tooth has passed near the crank angle sensor, calculates a time interval between the detected passages of the signal tooth, and detects a tooth notch position as a passing position of the tooth notch portion based on the time interval; a buffer portion for storing the time intervals calculated during a predetermined period as signal information; and The output processing unit counts the number of times the signal tooth passes through the tooth notch position as the crank plate rotates, that is, the number of crank angle sensor signals, and outputs the signal information until the counted number of crank angle sensor signals reaches a predetermined number.

2. The crank angle sensor control device according to claim 1, wherein: The predetermined number is set to 1 or 2.

3. The crank angle sensor control device according to claim 1 or 2, wherein: A determination unit is provided for determining abnormality in signal information of the crank angle sensor between the tooth notch positions based on the counted number of signals of the crank angle sensor between the tooth notch positions, The output processing unit outputs the signal information stored in the buffer unit together with the determination result of the determination unit.

4. The crank angle sensor control device according to claim 1 or 2, wherein: A determination unit is provided for determining abnormality in signal information of the crank angle sensor between the tooth notch positions based on the counted number of signals of the crank angle sensor between the tooth notch positions, When the determination unit determines that the signal information is abnormal, the output processing unit outputs the determination result of the determination unit and stops outputting the signal information stored in the buffer unit, or outputs a predetermined value instead of the signal information.

5. The crank angle sensor control device according to claim 1 or 2, wherein: A determination unit is provided for determining abnormality in signal information of the crank angle sensor between the tooth notch positions based on the counted number of signals of the crank angle sensor between the tooth notch positions, When the judgment unit judges the signal information to be abnormal, the output processing unit outputs the judgment result of the judgment unit, and outputs signal information that corrects the signal information stored in the buffer unit based on the signal information of the crank angle sensor input between the tooth notch positions on the crank disk.

6. The crank angle sensor control device according to claim 5, wherein: The signal information obtained by correcting the signal information stored in the buffer is calculated by extrapolating past signal information of the crank angle sensor determined to be normal.

7. The crank angle sensor control device according to claim 1 or 2, wherein: A determination unit is provided for determining abnormality in signal information of the crank angle sensor between the tooth notch positions based on the counted number of signals of the crank angle sensor between the tooth notch positions, When the determination unit determines that the signal information is abnormal, the buffer unit stops storing the signal information of the crank angle sensor for a predetermined period of time, or stores a predetermined value instead of the signal information stored in the buffer unit.

8. An internal combustion engine control device, characterized in that: The invention comprises a crank angle sensor control unit and a combustion detection control unit that receives signal information from the crank angle sensor control unit and performs processing related to combustion detection. The crank angle sensor control unit processes a voltage signal output by a crank angle sensor disposed opposite to a crank disk, wherein the crank disk includes a portion provided with a predetermined number of signal teeth and a tooth-notch portion provided with no signal teeth on a rotating circumference, and includes: a time interval calculation unit that detects, based on a voltage signal outputted from the crank angle sensor, that a portion provided with the signal tooth has passed near the crank angle sensor, calculates a time interval between the detected passages of the signal tooth, and detects a tooth notch position as a passing position of the tooth notch portion based on the time interval; a buffer portion for storing the time interval calculated during a predetermined period as signal information; and The output processing unit counts the number of times the signal tooth passes through the tooth notch position as the crank plate rotates, that is, the number of crank angle sensor signals, and outputs the signal information until the counted number of crank angle sensor signals reaches a predetermined number.

9. The internal combustion engine control device according to claim 8, wherein: When the combustion detection control unit determines that the signal information input from the crank angle sensor control unit has an abnormality, the combustion detection control unit immediately stops the process related to the combustion detection or fixes a value calculated from the combustion detection result to a predetermined value.

10. The internal combustion engine control device according to claim 9, wherein: An engine control unit is provided for controlling the internal combustion engine based on the combustion state detected by the combustion detection control unit. The engine control unit immediately stops control related to combustion detection when it is determined that there is an abnormality in the signal information input from the crank angle sensor control unit.

11. The internal combustion engine control device according to claim 9, wherein: An engine control unit is provided for controlling the internal combustion engine based on the combustion state detected by the combustion detection control unit. The engine control unit includes: an ignition control function for controlling ignition based on the combustion state detected by the combustion detection control portion; and The exhaust gas recirculation control function controls exhaust gas recirculation by causing part of the exhaust gas to flow back to the intake side based on the combustion state detected by the combustion detection control unit.

12. The internal combustion engine control device according to claim 10 or 11, wherein: The internal combustion engine is used exclusively for generating electricity to drive the generator of the hybrid system.

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