JP2018123735A - Crank angle detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crank angle detection device which creates a piston position signal corresponding to a missing tooth part, can create a cycle signal at each unit angle in a state that the missing tooth part does not exist, and also can create the piston position signal corresponding to the missing tooth part.SOLUTION: Signal teeth having first prescribed widths for generating rising timing and falling timing are formed at equal angle intervals, two of the signal teeth out of these signal teeth are set as the signal teeth whose falling timings are set at the same angle intervals as those of the other signal teeth, and whose rising timings are set at angle intervals which are retarded more than those of the other signal teeth, and which have second prescribed widths narrower than the first prescribed widths, a cycle signal at each unit angle is created on the basis of a count value of a falling cycle counter for performing counting at the falling timing of the signal teeth, and a piston position signal is created by controlling a counting state of the falling cycle counter on the basis of a count value of a rising cycle counter for performing counting at the rising timing of the signal teeth.SELECTED DRAWING: Figure 3A

Description

  The present invention relates to a crank angle detection device for an internal combustion engine.

  In an internal combustion engine equipped with a crank angle sensor that detects the rotation state of the crankshaft, the torque fluctuation generated during combustion is detected from the crankshaft rotation fluctuation, and fuel control and ignition control are performed so as to suppress the combustion fluctuation from the torque fluctuation. By doing so, the combustion is stabilized.

  In order to detect the torque fluctuation of the crankshaft that is rotating while repeating the intake stroke, compression, explosion, and exhaust, which are the operation strokes of the internal combustion engine, the fluctuation of the crankshaft rotational speed may be obtained. For this purpose, the elapsed time between the signal teeth of the signal plate for detecting the crank angle directly connected to the crankshaft can be measured, and the fluctuation of the rotational speed can be obtained based on the measured elapsed time.

  For example, if the signal teeth are provided on the signal plate at equal intervals of 10 °, a rectangular wave (unit angle signal) is detected every 10 ° when the crankshaft is rotated, and the falling of each rectangular wave is detected. By measuring the time interval (cycle), the rotation speed every 10 ° can be calculated. Then, from the obtained rotational speed per unit angle (every 10 °), the rotational fluctuation of the crankshaft is detected to obtain the torque fluctuation, and the combustion fluctuation is estimated based on this torque fluctuation.

  Such a crank angle detection device is described in, for example, Japanese Patent Application Laid-Open No. 2010-190174 (Patent Document 1). In Patent Document 1, the rotational speed of a crankshaft is calculated, and the combustion torque is calculated from the waveform of a predetermined frequency component in the rotational speed waveform by filtering the rotational speed waveform.

  Furthermore, as a method for improving the accuracy of angle detection, for example, in Japanese Patent Application Laid-Open No. 2006-098392 (Patent Document 2), the outputs from a plurality of crank angle sensors are compared with each other using an equal division averaging method. It has been proposed to self-calibrate.

JP 2010-190174 A JP 2006-098392 A

  Incidentally, in the fuel control and ignition control of the internal combustion engine, it is necessary to determine the position of the piston of the combustion cylinder. For this reason, in the signal plate, a missing tooth portion lacking a part of the signal tooth (for example, two 30 ° missing tooth portions in 360 °) is provided to generate a piston position signal. ing. However, since the unit angle signal by the signal teeth does not exist in this missing tooth region, the accuracy of detecting the rotational speed in that region portion is lowered.

  Therefore, when estimating combustion fluctuations from fluctuations in crankshaft rotation speed, it is necessary to increase the detection accuracy of the rotation speed, and at least the detection accuracy of the rotation speed due to the missing tooth portion that detects the piston position. It is desired to suppress the decrease in the above. However, on the other hand, in order to obtain the piston position of the combustion cylinder, a piston position signal generated by the missing tooth portion is required. Thus, there is a need for a crank angle detection device that generates a periodic signal for each unit angle without missing teeth and a piston position signal for missing teeth.

  An object of the present invention is to provide a novel crank angle detection device that generates a periodic signal for each unit angle in a state where there is no missing tooth portion, and also generates a piston position signal corresponding to the missing tooth portion.

  A feature of the present invention is that a first signal tooth having a first predetermined width formed at equiangular intervals for generating a rising timing and a falling timing over the entire outer periphery of the signal plate fixed to the crankshaft. And one or more predetermined number of signal teeth in the first signal teeth, the falling timing is set to the same angle interval as the first signal teeth, and the rising timing is delayed from the first signal teeth. The count value of the second signal tooth having the second predetermined width shorter than the first predetermined width and the falling period counter for counting at the falling timing of the first signal tooth and the second signal tooth Based on the count value of a period measuring means for generating a periodic signal at equal angular intervals based on the rising timing of the first signal tooth and the rising timing of the second signal tooth, and a falling period counter And a piston position measuring means for generating a piston position signal to control the counter reading of the data is in place.

  According to the present invention, the piston position signal corresponding to the missing tooth portion can be generated, and the periodic signal for each equiangular interval without the missing tooth portion can be generated, so that the piston position of the combustion cylinder can be detected, The rotational speed of the crankshaft can be detected with high accuracy.

1 is a configuration diagram of an internal combustion engine system to which the present invention is applied. It is a block diagram of the crank angle detection apparatus which becomes the 1st Embodiment of this invention. It is a time chart explaining operation | movement of the crank angle detection apparatus shown to FIG. 2A. It is a block diagram which shows the concrete control block of the control apparatus of the internal combustion engine which uses the crank angle detection apparatus shown to FIG. 2A. It is a time chart explaining operation | movement of the control block shown to FIG. 3A. It is a control flowchart which performs operation of a control block shown in Drawing 3A. It is a block diagram of the crank angle detection apparatus which becomes the 2nd Embodiment of this invention. It is a block diagram which shows the concrete control block of the crank angle detection apparatus shown to FIG. 4A. It is a block diagram of the conventional crank angle detection apparatus. It is a time chart explaining operation | movement of the conventional crank angle detection apparatus shown to FIG. 6A.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and application examples are included in the technical concept of the present invention. Is also included in the range.

  Before describing embodiments of the present invention, the configuration and operation of an internal combustion engine system to which the present invention is applied and a conventional crank angle detection device will be briefly described.

  FIG. 1 is a configuration diagram of an internal combustion engine 10 provided with a crank angle detection device of the present embodiment. The driving force of the internal combustion engine 10 is transmitted from the drive shaft (not shown) to the tire via the transmission 32 and then to the road surface. Here, the type of the internal combustion engine 10 may be any driving force source that travels the vehicle, and examples thereof include a port injection type or in-cylinder injection type gasoline internal combustion engine, a diesel internal combustion engine, and the like.

  The internal combustion engine 10 has a crankshaft 11, and a crankshaft pulley 11 a for driving an auxiliary machine with a belt is attached to one end of the crankshaft 11. A crank angle signal plate 12 for detecting a crank angle is provided on the crankshaft 11 so as to detect a crank angle signal. At the other end of the crankshaft 11, a ring gear and a torque converter, which are integral with a drive plate (not shown) for transmitting a driving force to the transmission, are attached.

  In the vicinity of the crank angle signal plate 12, a crank angle sensor 13 and a crank angle sensor 14 for detecting the unevenness of the pattern of the crank angle signal plate 12 and outputting a pulse signal are attached at positions opposite to each other at 180 °. Based on the pulse signals output from the crank angle sensors 13 and 14, the ECU 33 calculates the rotational speed of the crankshaft 11 of the internal combustion engine 10 (= the rotational speed of the internal combustion engine).

  Further, as intake system components of the internal combustion engine 10, an intake manifold hold (not shown) for distributing intake air to each cylinder, a throttle valve 22, a throttle opening sensor 21, an air flow sensor 23, and an air cleaner (not shown) are attached. Other sensors include a cooling water temperature sensor 24 that detects the temperature of the cooling water in the internal combustion engine, an intake air temperature sensor 25 that detects the temperature of the intake air to the internal combustion engine, and an air-fuel ratio that is detected from the oxygen concentration in the exhaust gas. The ECU 33 receives a signal from the cam angle sensor 18 for detecting the air-fuel ratio sensor 26 and the convex / concave pattern of the cam angle signal plate 17 attached to the tip of the camshaft.

  The output of the ECU 33 includes an injector 29 that performs fuel injection, an ignition plug 28 that ignites the air-fuel mixture in the cylinder, an ignition coil 27 that supplies high voltage to the ignition coil, and a high-pressure fuel pump solenoid that controls the fuel pressure. 30. The EGR valve 31 for recirculating the exhaust gas is driven. As an example, an electronically controlled throttle device is used for the throttle valve 22.

  The ECU (engine control unit) 33 calculates the optimum throttle opening based on the signal from the accelerator pedal sensor 19 that detects the amount of depression of the accelerator pedal 20 and signals sent from other sensors, and performs electronic control. Output to the throttle device. Thereby, the throttle valve 22 is controlled to an optimum throttle valve opening.

  The airflow sensor 23 measures the air flow rate sucked from the air cleaner and outputs it to the ECU 33. The ECU 33 calculates a fuel amount commensurate with the measured air amount, and outputs it to the injector 29 as a valve opening time. The injector 29 starts fuel injection at a timing when the crank angle indicated by the signals of the crank angle sensors 13 and 14 becomes the crank angle preset by the ECU 33.

  By this operation, the sucked air and the fuel injected from the injector 29 are mixed in the cylinder of the internal combustion engine 10 to form a combustible mixture. A high voltage boosted through the ignition coil 27 is applied to the spark plug 28 at a timing when the crank angle detected by the crank angle sensors 13 and 14 becomes a crank angle preset by the ECU 33. Thereby, the combustible air-fuel mixture in the cylinder is ignited and burns and explodes.

  The internal combustion engine 10 transmits the kinetic energy obtained by the combustion and explosion of the combustible air-fuel mixture to the crankshaft 11 via the piston 15 and the connecting rod 16 to generate a rotational driving force. A drive plate (not shown) is attached to the transmission side of the crankshaft 11. The drive plate is directly connected to the input side of a torque converter (not shown), and the output side of the torque converter is input to the transmission 32.

  One of the conventional techniques for reducing fuel consumption is lean burn combustion. After taking measures to reduce NOx such as catalysts, optimizing the shape of the combustion chamber and injector spray, etc., the fuel consumption is reduced by operating in a lean combustion state (lean burn) with an air-fuel ratio of “20” or higher. Technology. However, there is a limit to the air-fuel ratio that can be operated as a lean burn due to the performance and fuel properties of the internal combustion engine, variation between cylinders, operating conditions, etc., and the combustion generating torque fluctuates and becomes unstable near the lean limit, causing the drive system to It is transmitted to the driver and passengers as an unpleasant vibration.

  To operate an internal combustion engine in a stable lean combustion state, it is necessary to control the ignition timing, fuel injection amount, injection timing, etc. before the lean limit, and for that purpose, it is necessary to accurately detect the torque generated during combustion There is.

  As a method for detecting the torque generated during combustion, there is a method in which a pressure sensor is directly attached to a spark plug or a cylinder head of an internal combustion engine, and the pressure in the cylinder is directly measured and converted into torque. Further, as an indirect method, there are a method of measuring distortion and vibration of the cylinder outer wall and converting it to a torque through a filter, and a method of filtering a crankshaft rotation variation and converting it to torque. The present embodiment relates to a method of detecting the generated torque by detecting the rotational fluctuation of the crankshaft 11 among the methods of detecting the generated torque during combustion.

  Next, a conventional crank angle detection method for a four-cylinder internal combustion engine will be briefly described with reference to FIGS. 6A and 6B. By detecting the crank angle, the piston position of the combustion cylinder and the rotational speed of the crankshaft are detected. It can be done.

  In FIG. 6A, the crank angle signal plate 12 is directly connected to the crankshaft, and long signal teeth 12w having a first predetermined width are formed on the outer peripheral edge of the crank angle signal plate 12 at equal intervals of 10 °. Although not provided, missing tooth regions 12a and 12b lacking long signal teeth 12w for two teeth are provided every 180 °. The long signal teeth 12w are formed in an uneven shape along the axial direction, and a signal corresponding to the uneven shape can be obtained by a magnetic sensor using a GMR element or the like.

  When the crank angle signal plate 12 rotates with the rotation of the crankshaft 11, the crank angle sensor 13 detects irregularities of the long signal teeth 12w, and has a pattern like a signal rectangular wave 13a which is a unit angle signal in FIG. 6B. A rectangular wave is output to the ECU 33. The pattern of the rectangular wave 13a is basically a pulse every 10 °, but two missing pulses occur every 180 °. These two missing pulses are caused by the missing tooth region portions 12a and 12b.

  The ECU 33 starts the falling period counter with reference to the falling timing of the rectangular wave 13a, and adds the count value 13b of the falling period counter until the next falling timing, and from the added count value 13b It measures the cycle. Here, if the rotation speed is constant, the value of the count value 13b of the falling period counter is substantially “k”.

  The count value 13b of the falling cycle counter also corresponds to the pattern of the rectangular wave 13a, and is a count value corresponding to every 10 ° and a count value of 30 ° corresponding to the missing pulse generated every 180 °. Yes. Therefore, the angular speed (the rotational speed of the crankshaft) can be calculated by multiplying the period (time interval) between the falling timings measured by the count value 13b of the falling period counter by the unit time.

  Further, as shown in FIG. 6B, the missing tooth region portions 12a and 12b have a period corresponding to 30 °. Therefore, the timing determined by the missing tooth region portions 12a and 12b is, for example, 50 ° before the compression top dead center. It can be set as a reference. The calculation method of the piston position by the missing tooth region portions 12a and 12b can be performed by a known method.

  Then, the piston position is detected based on the timing generated in the missing tooth regions 12a and 12b, and the fuel injection start timing and injection end timing, and the energization start timing and energization end timing (= ignition timing) of the ignition coil are detected. Control can be executed. Therefore, the piston position information generated by the missing tooth regions 12a and 12b is essential control information for controlling the internal combustion engine.

  In this way, by providing the missing tooth regions 12a and 12b in the crank angle signal plate 12, the reference of the fuel injection timing and the ignition timing necessary for the control of the internal combustion engine can be determined, but when the rotational speed is measured Since there is no update of the period information of the 30 ° section of the missing tooth regions 12a, 12b, there is a section where the rotational speed detection accuracy is inferior to that of the other 10 ° sections. Therefore, when the combustion fluctuation is obtained from the rotation fluctuation of the crankshaft 11, the accuracy is improved if the rotation speed is obtained by a rectangular wave signal of 36 teeth every 10 ° without the missing tooth regions 12a and 12b. desirable.

  For this purpose, it is conceivable to provide a crank angle signal plate for detecting combustion fluctuations and a crank angle signal plate for detecting the piston position of the combustion cylinder. And an additional input port of the ECU are required, which causes a new problem of increasing the cost.

  In order to cope with the above-described problem, the first embodiment of the present invention generates a piston position signal corresponding to a missing tooth portion by one crank angle signal plate, and is a unit in a state where there is no missing tooth portion. The present invention proposes a crank angle detection device capable of generating a periodic signal for each angle.

  Next, the first embodiment of the present invention will be described in detail with reference to FIGS. 2A to 4. FIG. 2A shows the configuration of the crank angle detection device, and FIG. 2B shows a time chart of the cycle counter based on the signal tooth fall timing and rise timing. FIG. 3A shows a specific control block of the control device for the internal combustion engine, and FIG. 3B shows a time chart of a cycle counter based on the signal tooth fall timing and rise timing by the control block of FIG. 3A. Furthermore, FIG. 4 shows a control flowchart for executing the operation of the control block.

  In FIG. 2A, 36 signal teeth are provided on the outer periphery of the crank angle signal plate 12 every 10 ° at equal angular intervals, and long signal teeth (first signal teeth) formed to have a first predetermined width. 12n and a short signal tooth (second signal tooth) 12n having a second predetermined width shorter than the first predetermined width of the signal tooth 12w are provided.

  The short signal teeth 12n having the second predetermined width are provided in the short signal tooth region portions 12c and 12d at intervals of 180 ° corresponding to the conventional missing tooth region portions 12a and 12b. In the present embodiment, two short signals teeth are formed. No. teeth 12n are provided. The short signal teeth 12n are composed of a leading short signal tooth 12n1 and a trailing short signal tooth 12n2 when viewed in the rotation direction, and the widths thereof are the same.

  Here, when viewed in the rotation direction of the crank angle signal plate 12, the falling timing positions of the short signal teeth 12n1 and 12n2 are the same positions as the falling timing positions of the other long signal teeth 12w and are equiangularly spaced. is necessary. In other words, the falling timing positions of the short signal teeth 12n and the long signal teeth 12w are set at 10 ° intervals, whereby the falling timing can be obtained every 10 ° on the entire circumference of the crank angle signal plate 12.

  On the other hand, when viewed in the rotation direction of the crank angle signal plate 12, the rising timing position of the short signal teeth 12n is delayed from the rising timing positions of the other long signal teeth 12w. As a result, the rising timing for determining the piston position every 180 ° can be obtained. The long signal teeth 12w and the short signal teeth 12n are formed in a concavo-convex shape along the axial direction, and a signal corresponding to the concavo-convex shape can be obtained by a magnetic sensor using a GMR element or the like. It is.

  Here, the ECU 33 can detect the rising timing and the falling timing of both signal teeth 12w and 12n, and further, the rising cycle counter that can detect the cycle between the respective rising timings, and the cycle between the respective falling timings. A falling period counter capable of detection is provided. In order to detect the rise timing and fall timing of such signal teeth 12w and 12n, it is possible to detect by comparing the values before and after the detection signal generated by the signal teeth, and this method is well known. Technology. In addition, it may be detected by other methods.

  Therefore, the start and reset of each period counter can be controlled according to the rising timing and falling timing. The period counter of this embodiment starts counting of the count value in synchronization with the reset of the count value.

  When the crank angle signal plate 12 rotates with the rotation of the crankshaft 1, the crank angle sensor 13 detects the irregularities of the long signal teeth 12w and the short signal teeth 12n, as shown by the rectangular wave 13c in FIG. 2B. The rectangular wave of the pattern is output to the ECU 33. The pattern of the rectangular wave 13c is 36 pulses whose falling timing position is every 10 ° per rotation of the crankshaft 11. However, the pulse width of the short signal teeth 12n of the short signal tooth region portions 12c and 12d has a pulse width. It is getting shorter. The pulse of the short signal tooth 12n functions as the missing tooth region 12a, 12b.

  The ECU 33 starts the falling cycle counter based on the falling timing of the rectangular wave 13c, adds the count value 13d of the falling cycle counter until the next falling timing, and measures the cycle from the added count value 13d. To do. That is, as shown in the count value 13d obtained by measuring the period between the falling timings, a waveform that repeats counting up every 10 ° is formed. Here, if the rotation speed is constant, the value of the count value 13d of the period counter is approximately “k”.

  Therefore, by multiplying the period between the falling timings measured by the count value 13d of the falling counter by the unit time, the angular velocity every 10 ° can be calculated over the entire circumference of the crank angle signal plate 12. As described above, the crank angle signal plate 12 according to the present embodiment does not include the missing tooth region portions 12a and 12b, so that the rotational speed detection accuracy can be improved.

  On the other hand, the ECU 33 starts the rising cycle counter based on the rising timing of the rectangular wave 13c, adds the count value 13e of the rising cycle counter until the next rising timing, and measures the cycle from the added count value 13e. Here, since the pulse width of the short signal tooth 12n is short, the count value 13e obtained by measuring the rising period has an unequal pitch in the short signal tooth region portions 12c and 12d, and therefore, the other long signal tooth 12w. Thus, a characteristic waveform is formed only in the sections of the short signal tooth region portions 12c and 12d. By controlling the count state of the falling cycle counter using this characteristic waveform, the count value equivalent to the missing tooth portions 12a and 12b is formed in the count value of the falling cycle counter.

  The short signal tooth region 12c will be described as a representative example. The rising period counter started at the rising timing t1 of the long signal tooth 12w immediately before the pulse Pls1 of the preceding short signal tooth 12n1 performs the counting operation while performing the counting operation. It is reset at the rising timing t2 of the No. 12n1. And since the arrival of the rising timing of the short signal teeth 12n1 is delayed, the value of the count value 13e becomes a “Ka” value larger than the “K” value.

  Next, since the angle between the rising timing t2 of the preceding short signal tooth 12n1 and the rising timing t3 of the following short signal tooth 12n2 is 10 °, the value of the count value 13e becomes “K” value. Yes. This is the same value as the count value of the other long signal teeth 12w.

  On the other hand, the rising period counter started at the rising timing t3 of the pulse Pls2 of the trailing short signal tooth 12n2 is reset at the rising timing t4 of the long signal tooth 12W immediately after the pulse Pls2 of the trailing short signal tooth 12n2. Since the rising timing of the short signal tooth 12n2 is delayed, the value of the count value 13e is a “Kb” value smaller than the “K” value.

  Therefore, the range in which the value of the rising period counter is between the “Ka” value and the “Kb” value can be regarded as the conventional missing tooth regions 12 a and 12 b. Therefore, if this is used to control the count state of the falling period counter, the same count value as in the conventional missing tooth regions 12a and 12b can be obtained, and the fuel control and ignition control executed by the ECU 33 can be obtained. Fuel control and ignition control can be executed without significantly modifying the software.

  FIG. 3A shows the count value 13h of the falling period counter corresponding to the missing tooth regions 12a and 12b shown in FIG. 6B from the count value 13d of the falling period counter and the count value 13e of the rising period counter acquired in FIG. 2B. The control block to be generated is shown.

  In FIG. 3A, the signal of the crank angle sensor 13 is input to a falling period measuring unit 34 and a rising period measuring unit 35 provided in the ECU 33. In the falling period measuring means 34, as shown in FIG. 2B, a count value 13d is formed by a falling period counter, and this counted value 13d is sent to the rotation fluctuation measuring means 37 and the missing tooth section generating means 36.

  In the rotation fluctuation measuring means 37, since the count value 13d is inputted by the falling period counter shown in FIG. 2B, the long signal teeth 12w and the short signal formed at equal angular intervals over the entire circumference of the crank angle signal plate 12. The rotational speed is obtained based on a cycle of every 10 ° corresponding to the falling position of the tooth No. 12n. Therefore, since the missing tooth region portions 12a and 12b do not exist, it is possible to suppress a decrease in rotational speed detection accuracy caused by the conventional missing tooth region portions 12a and 12b.

  On the other hand, the rising period measuring means 35 forms a count value 13e by a rising period counter as shown in FIG. 2B, and this counted value 13e is sent to the missing tooth section generating means 36. The missing tooth section generation means 36 determines the presence of the short signal tooth 12n from the count value 13e by the rising period measuring means 35 and generates a missing tooth section generation flag, which will be described later, and the falling period counter generates a falling period counter. The count state is controlled, and the count value similar to that of the conventional missing tooth regions 12a and 12b is formed in the count value by the falling period measuring means 34 to obtain the piston position signal.

  Next, a method of generating a count value 13h similar to the missing tooth regions 12a and 12b using the count value 13d of the falling period counter and the count value 13e of the rising period counter will be described with reference to FIG. 3B.

  After the rising period counter starts counting from the rising timing t1, at the rising timing t2, the missing tooth section detection flag is set to “1” and the rising period counter is reset. The count value 13e at this time is equal to or greater than the “Ka” value, and is larger than the count value “K” value in the case of the long signal tooth 12w. Thus, it can be determined that the short signal tooth region 12c has been entered.

  The timing for setting the missing tooth section detection flag to “1” is sufficient if the rising timing of the preceding short signal tooth 12n1 can be detected. There are various methods for this, but the rising timing of the preceding short signal tooth 12n1 is determined when the counting direction of the rising period counter exceeding the count value “K” changes from the “+” direction to the “−” direction. It is also good. In short, it suffices if the rising timing of the preceding short signal tooth 12n1 can be detected, whereby it can be determined that the short signal tooth region 12c (corresponding to the missing tooth region 12a) has entered.

  Next, simultaneously with the reset at the rising timing t2, the rising cycle counter starts counting again. Here, when the rising timing of the preceding short signal tooth 12n1 is detected, the next cycle is the preceding short signal tooth. 12n1 and the following short signal tooth 12n2, it has been found that this section is regarded as the short signal tooth region 12c (corresponding to the missing tooth region 12a) and the missing tooth detection flag “ 1 ”is maintained. At the rising timing t3, the rising cycle counter is reset.

  Next, simultaneously with the reset at the rise timing t3, the rise cycle counter starts counting again, but at the rise timing t4, the missing tooth section detection flag is set to “0” and the rise cycle counter is reset. The count value 13e at this time is equal to or less than the “Kb” value, and is smaller than the count value “K” value in the case of the long signal tooth 12w. The timing for clearing the missing tooth section detection flag to “0” is sufficient if the rising timing of the long signal tooth 12w immediately after the trailing short signal tooth 12n2 can be detected.

  There are various methods for this, but the time point when the counting direction of the rising period counter, which is less than the count value “K”, changes from the “+” direction to the “−” direction is immediately after the trailing short signal tooth 12n2. The rise timing of the long signal teeth 12w may be good. In short, it is only necessary to detect the rising timing of the long signal tooth 12w immediately after the trailing short signal tooth 12n2, and by this, the short signal tooth region 12c (corresponding to the missing tooth region 12a) is removed. Can be judged.

  Accordingly, the section “Flg1” of the missing tooth section detection flag “1” corresponds to the missing tooth section region 12a. Therefore, if the counting operation of the falling period counter started at the falling timing is continued only during the section “Flg1”, a counting waveform similar to that of the missing tooth region 12a can be obtained.

  That is, the count value 13d of the falling period counter is changed in the count state by the above-mentioned missing tooth section detection flag. Since the time when the missing tooth section detection flag becomes “1” is the rising timing t2 of the preceding short signal tooth 12n1, when the missing tooth section detection flag becomes “1”, the falling timing of the falling period counter The reset operation by is shifted to the invalid state. Therefore, even if the falling timing t5 of the preceding short signal tooth 12n1 after the missing tooth section detection flag becomes “1” arrives, the count value of the falling period counter at the falling timing t5 is not reset, The counting is continued as it is, and the counting operation such as the counting value 13h is performed.

  When the missing tooth section detection flag becomes “0” at the rising timing t4 of the long signal tooth 12w immediately after the trailing short signal tooth 12n2, the reset operation based on the falling timing of the falling period counter is returned to the valid state. Let Therefore, the falling period counter is reset at the falling timing t6 of the long signal tooth 12w immediately after the trailing short signal tooth 12n2. Thereafter, the counting operation is repeated at the falling timing of the long signal tooth 12w until the next short signal tooth region 12d.

  In this way, by controlling the counting state of the falling period counter with the missing tooth section detection flag formed by the preceding short signal tooth 12n1 and the following short signal tooth 12n2, the same as the missing tooth regions 12a and 12b. Can be obtained, and a piston position signal can be generated.

  Since the above-described control is basically executed by a microcomputer built in the ECU 33, the control flow for executing the above-described control will be briefly described with reference to FIG.

  In FIG. 4, the control of the rising period counter and the control of the falling period counter are executed in parallel in a time division manner.

  First, control of the rising cycle counter will be described. In step S11, a crank angle sensor signal is captured, and this signal is indicated by a rectangular wave 13c in FIG. 3B. When the capturing of the rectangular wave 13c is completed, the process proceeds to the next step S12. In step S12, it is determined whether or not the input signal has changed from “0V” to “5V”. This detects the rising timing of the long signal teeth 12w and the short signal teeth 12n. If it is not the rising timing, the process returns to step S11 again. If it is the rising timing, the process proceeds to step S13.

  In step S13, counting is performed in synchronization with the rising timing by the rising cycle counter to form the count value 13e of FIG. 3B. When this counting is completed, the process proceeds to step S14.

  In step S14, it is determined whether or not it is the rising timing of the preceding short signal tooth 12n1 from the count value 13e of the rising cycle counter in FIG. 3B. If it is the rising timing of the preceding short signal tooth 12n1, the process proceeds to step S15, and if it is not the rising timing of the preceding short signal tooth 12n1, the process proceeds to step S16. In step S15, since it is determined that it is the rising timing of the preceding short signal tooth 12n1, the missing tooth section generation flag in FIG. 3B is set to “1” and the process returns to step S11 again.

  On the other hand, in step S16, since it is determined in step S14 that it is not the rising timing of the preceding short signal tooth 12n1, it is determined whether or not it is the rising timing of the long signal tooth 12w immediately after the succeeding signal tooth 12n2. . If it is determined that the rising timing of the long signal tooth 12w immediately after the trailing signal tooth 12n2 is reached, the process proceeds to step S17, and if it is determined that it is not the rising timing of the long signal tooth 12w immediately after the trailing signal tooth 12n2. The process proceeds to S18.

  In step S17, it is determined that it is the rising timing of the long signal tooth 12w immediately after the succeeding signal tooth 12n2, so the missing tooth section generation flag in FIG. 3B is set to “0” and the process returns to step S11 again. . On the other hand, in step S18, since it is determined in step S16 that it is not the rising timing of the long signal tooth 12w immediately after the following signal tooth 12n2, the rising period counter is reset to correspond to the long signal tooth 12w in FIG. 3B. The counting is repeated. When the rising cycle counter is reset, the process returns to step S11 again.

  The count value 13e of the rising period counter in FIG. 3B and the missing tooth section generation flag are obtained by the control steps from Step S11 to Step S18. The missing tooth section generation flag is used for controlling the falling period counter, and generates count values corresponding to the missing tooth areas 12a and 12b.

  Next, the control of the falling period counter will be described. In step S21, a signal from the crank angle sensor is captured, and this signal is also shown by the rectangular wave 13c in FIG. 3B. When the capturing of the rectangular wave 13c is completed, the process proceeds to the next step S22. In step S22, it is determined whether or not the input signal has changed from “5V” to “0V”.

  This detects the falling timing of the long signal teeth 12w and the short signal teeth 12n. If it is not the falling timing, the process returns to step S21 again, and if it is the falling timing, the process proceeds to step S23. In step S23, the count value 13d is formed by repeating the start and reset of the count in synchronization with the respective fall timings by the fall cycle counter of FIG. 3B. When the counting of the counted value 13d is completed, the process proceeds to step S24.

  In step S24, it is determined whether the missing tooth section generation flag set in steps S14 and S15 described above is “1” or “0”. When the missing tooth section generation flag is “1”, the process proceeds to step S26, and when the missing tooth section generation flag is “0”, the process proceeds to step S25.

  In step S26, since the missing tooth section generation flag is “1”, as shown in FIG. 3B, the reset operation by the falling timing is invalidated in the falling period counter, and the counting operation of the falling period counter is continued. The As a result, the falling period counter performs a counting operation such as the count value 13h. In step S25, since the missing tooth section generation flag is “0”, the falling period counter is reset at the next falling timing. After this, the process returns to step S21.

  The count value 13g of the falling period counter of FIG. 3B is obtained by the control steps from step S21 to step S26.

  In this way, the piston position signal can be generated by the count value 13g of the falling cycle counter that has generated the missing tooth section, so that the piston position of the combustion cylinder can be detected and the missing value can be detected by the count value 13d of the falling cycle counter. Since it is possible to generate a periodic signal for each equiangular interval in a state where there is no portion, the rotational speed of the crankshaft can be detected with high accuracy.

  Therefore, there is no need to provide a crank angle signal plate for determining the rotational speed, a crank angle signal plate for determining the piston position signal, and a corresponding crank angle sensor, and a significant system change, weight increase, and addition of a sensor harness Since it is not necessary to increase the input port of the ECU, it is possible to construct a control system that suppresses the increase in cost.

  Next, a second embodiment of the present invention will be described with reference to FIGS. 5A and 5B. In the present embodiment, an example is shown in which two crank angle sensors are used to detect the rotational speed of the crankshaft. Here, since the same reference numerals as those shown in FIGS. 2A and 3A are the same component parts, the description thereof is omitted.

  As shown in FIG. 5A, in addition to the crank angle sensor 13, a second crank angle sensor 14 is disposed at a position opposed to 180 °. The crank angle sensor 14 has the same configuration as the crank angle sensor 13 and generates a rectangular wave having the same pattern as the rectangular wave 13c shown in FIG. 2B.

  Further, as shown in FIG. 5B, the ECU 33 is provided with a second falling period measuring means 39, and the second falling measuring means 39 includes a rectangular wave 13c from the second crank angle sensor 14. Is entered. The operation of the second falling period measuring means 39 is to execute the same counting operation as that of the first falling period measuring means 34.

  The count values 13d and 14d of the first falling period measuring means 34 and the second falling period measuring means 39 are input to the angle error calibration means 40, and the error is calibrated. As a method of calibrating this error and increasing the measurement accuracy of the rotational speed, the equal division averaging method disclosed in Patent Document 2 can be used. The equal division averaging method self-calibrates by comparing the output signals of the two crank angle sensors 13 and 14 with each other, so that the detection accuracy can be improved. The periodic signal of the angle error calibrating means 40 is input to the rotation fluctuation detecting / measuring means 37, and the fluctuation of the rotation speed is obtained.

  According to the second embodiment, the angle error can be calibrated by using the equal division averaging method, and the rotation speed can be measured with higher accuracy.

  As described above, according to the present invention, the first of the first predetermined width formed at equal angular intervals for generating the rising timing and the falling timing over the entire outer periphery of the signal plate fixed to the crankshaft. The signal teeth and a predetermined number of signal teeth of one or more of the first signal teeth are set at the same angular interval as the first signal teeth, and the rising timing is delayed from the first signal teeth. A second signal tooth having a second predetermined width shorter than the first predetermined width, set at an angular interval, and a falling period counter for counting at the falling timing of the first signal tooth and the second signal tooth Falling on the basis of the count value of a period measuring means for generating a periodic signal for each equiangular interval based on the count value, and a rise period counter for counting at the rise timing of the first signal tooth and the second signal tooth And a piston position measuring means for generating a piston position signal to control the counter reading of the period counter, and a configuration.

  According to this, by providing the first signal tooth having the first predetermined width and the second signal tooth having the second predetermined width, the piston position signal corresponding to the missing tooth portion is generated, and the missing tooth portion is Since it is possible to generate a periodic signal for each equiangular interval in a non-existing state, it is possible to detect the piston position of the combustion cylinder and to detect the rotational speed of the crankshaft with high accuracy.

  In addition, this invention is not limited to above-described embodiment, Various modifications are included. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine body, 11 ... Crankshaft, 11a ... Crankshaft pulley, 12 ... Crank angle signal plate, 12w ... Long signal tooth, 12n ... Short signal tooth, 12c, 12d ... Short signal tooth region, 12n1 ... Lead side short Progressive teeth, 12n2 ... trailing short-travel teeth, 13 ... first crank angle sensor, 14 ... second crank angle sensor, 15 ... piston, 16 ... connecting rod, 17 ... cam angle signal plate, 18 ... cam angle sensor , 19 ... Accelerator pedal sensor, 20 ... Accelerator pedal, 21 ... Throttle opening sensor, 22 ... Throttle valve, 23 ... Airflow sensor, 24 ... Cooling water temperature sensor, 25 ... Intake air temperature sensor, 26 ... Air-fuel ratio sensor, 27 ... Ignition coil, 28 ... Spark plug, 29 ... Injector, 30 ... High pressure fuel pump, 31 ... EGR valve, 32 ... Lance Mission, 33 ... ECU, 34 ... falling period measuring means, 35 ... rising period measuring means, 36 ... dropout interval generation means, 37 ... rotational fluctuation measuring means, 38 ... engine control unit.

Claims (5)

First signal teeth of a first predetermined width formed at equiangular intervals for generating a rising timing and a falling timing over the entire outer periphery of the signal plate fixed to the crankshaft;
The falling timing of one or more predetermined number of signal teeth of the first signal teeth is set at the same angular interval as that of the first signal teeth, and the rising timing is delayed from the first signal teeth. A second signal tooth having a second predetermined width shorter than the first predetermined width, set at an angular interval;
A crank angle sensor for detecting the rising timing and the falling timing of the first signal teeth and the second signal teeth of the signal plate;
Period measurement for generating a periodic signal for each equiangular interval based on the count value of a falling period counter that repeats the counting operation at the falling timing of the first signal tooth and the second signal tooth from the crank angle sensor Means,
Based on the count value of the rising period counter that repeats the counting operation at the rising timing of the first signal tooth and the second signal tooth from the crank angle sensor, the count state of the falling period counter is controlled to control the piston position. A crank angle detecting device comprising piston position measuring means for generating a signal. The crank angle detection device according to claim 1,
The falling period counter of the period measuring means repeats counting at equal angular intervals corresponding to the falling timing, and the rising period counter of the piston position measuring means counts corresponding to the rising timing. Repeat and
The piston position measuring means specifies the section of the second signal tooth by the rising period counter and invalidates the reset operation by the falling timing of the falling period counter only in the section of the second signal tooth. And a falling cycle counter control means for continuing the counting operation of the falling counter. In the crank angle detection device according to claim 2,
The falling period counter control means specifies the section of the second signal tooth based on a count value of the rising period counter, and the falling period counter of the falling period counter based on a signal representing the section of the second signal tooth A crank angle detecting device characterized in that the reset operation at the falling timing is invalidated and the counting operation of the falling counter is continued. In the crank angle detection device according to claim 3,
2. The crank angle detecting device according to claim 1, wherein the second signal tooth is formed of two signal teeth, a leading signal tooth and a trailing signal tooth. In the crank angle detection device according to claim 2,
The crank angle sensor comprises a first crank angle sensor and a second crank angle sensor having the same configuration,
The period measuring means comprises first period measuring means and second period measuring means having the same configuration corresponding to the first crank angle sensor and the second crank angle sensor,
The crank angle detection device characterized in that the periodic signals from the first period measuring means and the second period measuring means are input to an angle error calibration means to calibrate the periodic signals.

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