JP4069902B2 - Engine control device - Google Patents

Description

  The present invention relates to an engine control apparatus that controls an engine, and more particularly to an engine control apparatus that estimates a stop position of a crankshaft when the engine is stopped and uses the estimated stop position at the next engine start.

  Conventionally, in an engine control device, a crankshaft rotation signal output from a crankshaft sensor according to the rotation of the crankshaft of the engine and the rotation of the camshaft of the engine that rotates at a ratio of 1/2 with respect to the rotation of the crankshaft. Accordingly, the rotational position per one engine cycle is specified from the cam shaft rotation signal output from the cam shaft sensor in response to this, and ignition and fuel injection to the engine are started after the specification (for example, see Patent Document 1). ).

  A specific example will be described. First, in the crankshaft rotation signal output from the crankshaft sensor, a pulse edge is generated every time the crankshaft rotates by a predetermined angle, and the rotation position of the crankshaft is set in advance. When the reference position is reached, a missing tooth portion in which a predetermined number (for example, two) of the pulse edges are missing appears. The camshaft rotation signal output from the camshaft sensor changes between a high level and a low level according to the rotation of the camshaft. The levels are alternately different.

  Then, the engine control device performs a missing tooth determination for determining whether or not a missing tooth portion appears in the crankshaft rotation signal, and the camshaft rotation signal level when it is determined that the missing tooth portion appears in the missing tooth determination. From this, the rotational position of the engine is specified. For example, if the camshaft rotation signal is at a high level at the time of missing tooth determination, the current rotation position is specified as a predetermined rotation position “X ° CA”, and the camshaft rotation signal is determined at the time of missing tooth determination. If the level is low, the current rotational position is specified as a rotational position advanced by 360 ° CA from “X ° CA”.

  “° CA” represents a crank angle (crank angle), and the rotational position of the engine is specified by a crank angle (0 ° CA to 720 ° CA) corresponding to two rotations of the crankshaft. In addition, this type of engine control apparatus measures the pulse interval of the crankshaft rotation signal (that is, the interval at which the pulse edge for each predetermined angle occurs in the crankshaft rotation signal) and the previously measured pulse interval T1 and the previous time. Compared with the measured pulse interval T0, for example, when the missing tooth determination condition that the ratio of T1 and T0 (= T1 / T0) is equal to or greater than a predetermined determination ratio is satisfied, the crankshaft rotation signal is It is determined that a missing tooth portion has appeared.

  However, in the above-described technique, generally, from the start of cranking by the starter at the start of the engine, until the reference position such as the missing tooth portion in the crankshaft rotation signal is detected and the crank position is first specified, A few revolutions of the crankshaft are required.

  For this reason, when the engine is started by the starter, the control of ignition and injection to the engine cannot be started quickly, and the fuel leaked from the injector (fuel injection valve) before starting or the unburned gas remaining in the intake pipe However, there is a problem that the exhaust is exhausted as it is and the emission is deteriorated. In particular, in order to satisfy exhaust gas regulations that are becoming more and more strict in recent years, it is important to burn up fuel almost simultaneously with starter start-up so that unburned gas and raw gas are not sent to the exhaust pipe. However, the above-described conventional engine control device cannot meet such a demand.

Therefore, in order to start the engine control quickly when the engine is started by the starter and improve the emission, the engine stop position is estimated by evaluating the crankshaft rotation signal and the camshaft rotation signal when the engine stops. Then, at the next engine start, it has been proposed to start engine control based on the estimated stop position (see, for example, Patent Document 2).
JP 2001-90600 A Japanese translation of PCT publication No. 8-5069797

  According to the proposed engine control device, when the engine is started, engine control is started based on the engine stop position estimated when the engine is stopped. Therefore, fuel is burned immediately after the engine is started, and unburned gas and raw gas are exhausted. It can be prevented from being sent to the pipe.

  However, if the stop position estimated when the engine is stopped is incorrect, or if the stop position changes between when the engine is stopped and the next start, the control timing at the start of engine control will deviate from the appropriate timing, There arises a problem that the engine cannot be started or the emission at the time of starting the engine is deteriorated.

  Therefore, in order to prevent such a problem, the applicant of the present application is configured to output a cam shaft rotation signal that changes according to the rotational position of the engine, and the cam shaft sensor is estimated when the engine is stopped. We considered starting engine control by specifying the engine rotation position from the stop position and changes in the camshaft rotation signal output from the camshaft sensor when the engine was started (rising edge, falling edge, etc.) .

  In other words, when the engine is started, the engine control position can be properly executed according to the actual engine rotation position by specifying the engine rotation position using the stop position estimated when the engine is stopped and the camshaft rotation signal. To do.

  However, in this way, when the engine is started, the engine control position can be started at an appropriate control timing using the stop position estimated when the engine is stopped, but the engine rotation position can be specified by the rotation position of the camshaft. Depending on the situation, the start timing of engine control may be delayed compared to the case where the engine rotation position is specified using the missing tooth portion of the crankshaft rotation signal. Arise.

  The present invention has been made in view of these problems, and is an engine control device that starts engine control using a stop position estimated when the engine is stopped, and the engine control is performed in accordance with the actual rotational position of the engine. The aim is to be able to start earlier with timing.

The engine control apparatus as set forth in claim 1, 2 has been made in order to achieve the above object, a camshaft sensor for generating a camshaft rotation signal that varies in accordance with the rotational position of the cam shaft of the engine, the engine crankshaft A crankshaft sensor that generates a crankshaft rotation signal at every predetermined rotation angle of the shaft, and when the engine stops from the operating state, the stop position estimation means includes at least a camshaft rotation signal and a crankshaft rotation signal. Based on one, the rotation stop position of the engine is estimated.

  Further, when the engine is started, the first rotational position specifying means specifies the rotational position per one cycle of the engine based on the stop position estimated by the stop position estimating means and the cam shaft rotation signal, and the second The rotational position specifying means specifies the rotational position per engine cycle based on at least one of the crankshaft rotation signal and the camshaft rotation signal.

  The engine control device according to the present invention specifies the engine position when the engine rotational position is specified by the first rotational position specifying means or when the rotational position is specified by the second rotational position specifying means. The engine control based on the rotation position thus started is started, and then the engine control is executed while updating the rotation position of the engine based on the crankshaft rotation signal.

That is, in the engine control device of the present invention, when the engine is started, the engine stop position estimated when the engine is stopped is not used as it is, but the engine control is started. Even if the engine rotation position is specified based on the stop position and the cam shaft rotation signal to start engine control, and the first rotation position specifying means can specify the rotation position, When the second rotational position specifying means can specify the engine rotational position earlier than the rotational position specifying means, the engine control is started based on the specified rotational position of the engine.

  Therefore, according to the engine control apparatus of the present invention, the engine control at the time of starting the engine can be properly started according to the actual rotational position of the engine, and the start timing can be made earlier.

Here, the second rotational position specifying means is for specifying the rotational position of the engine at the time of starting the engine without using the stop position estimated when the engine is stopped . the crankshaft sensor, as in the conventional crankshaft sensors described above, by utilizing a toothless like, the crankshaft rotation signal becomes discontinuous relative to the rotation of the crankshaft at a specific rotational angular position of the crankshaft In this case, since the two rotational positions (X ° CA, X + 360 ° CA) having a phase difference of one crankshaft rotation (360 ° CA) can be detected alternately from the crankshaft rotation signal , the second The rotational position specifying means detects a specific rotational angle position of the crankshaft from the crankshaft rotation signal output from the crankshaft sensor, and the rotational position of the engine at that time is the above 2 Of one and whether of the rotational position may be configured to identify from the state of change of the crankshaft rotation signal or the cam shaft rotation signal.

  In this case, in order for the second rotational position specifying means to be able to specify the rotational position of the engine from the change state of the camshaft rotational signal, the camshaft sensor is used at a specific rotational angle position of the crankshaft. The camshaft sensor may be configured so that the output level of the engine changes alternately between a high level and a low level as the engine rotates.

  Further, when the number of cylinders of the engine is an odd number, the change state of the crankshaft rotation signal is different from each other at two rotation positions (X ° CA, X + 360 ° CA) that can be detected from the crankshaft rotation signal. Since the rotational position of the engine can be specified depending on whether the interval between the shaft rotational signals is becoming shorter or longer, the second rotational position specifying means determines the rotational position of the engine from the change state of the cam shaft rotational signal. When specifying, the present invention may be applied to a control device for controlling an odd-numbered cylinder engine.

On the other hand, since the camshaft rotation signal changes according to the rotation position of the camshaft that rotates at a rate of once per engine cycle, the rotation position of the engine can be specified from the change waveform of the camshaft rotation signal. . Therefore, the second rotational position specifying means can be configured to specify the rotational position of the engine based on the change waveform of the camshaft rotational signal .

Further, when the second rotational position specifying means is configured as described in claim 1, as described in claim 3, the third rotational position specifying means is further used as a third rotational position specifying means. Rotational position specifying means for specifying the rotational position of the engine based on the change waveform is provided, and at the start of the engine, the rotational position of the engine is first specified by any of the first, second, and third rotational position specifying means. At this time, the engine control may be started based on the specified rotational position. In this way, engine control can be started earlier when the engine is started.

  Next, the stop position estimation means estimates the rotation stop position of the engine based on at least one of the camshaft rotation signal and the crankshaft rotation signal. When the engine is stopped, the stop position estimation means is dead in the cylinder in the compression stroke immediately before the engine is stopped. Since the crankshaft and the camshaft may reversely rotate without exceeding the point (TDC), the stop position estimating means has a camshaft rotation signal or A rotation direction determination means for determining whether the engine is rotating forward or backward from the change state of the crankshaft rotation signal is provided, and the engine stop position is estimated according to the determination result by the rotation direction determination means. Good.

  In other words, if the stop position estimating means is provided with the rotation direction determining means so as to determine the rotation direction of the engine when the engine is stopped, an estimation error of the stop position by the stop position estimating means can be suppressed. .

  As described above, when the rotation direction determination means determines the rotation direction of the engine when the engine is stopped from the camshaft rotation signal or the crankshaft rotation signal, the edge change direction and the edge time of the rotation signal are determined. Although the rotational direction of the engine is determined from the change state of the interval, there may be a region where the rotational direction of the engine cannot be accurately determined depending on the structure of the sensor or the like.

  Therefore, when the engine rotation direction cannot be specified by the rotation direction determination unit, the stop position estimation unit determines the engine stop position during normal engine rotation and reverse engine rotation as described in claim 4. The first rotational position specifying means may be configured to specify the rotational position of the engine using the estimated plurality of stop positions and the camshaft rotation signal.

  Further, in order to improve the determination accuracy of the rotation direction by the rotation direction determination means, as described in claim 5, the rotation direction determination means is a first that determines the rotation direction of the engine from the change state of the camshaft rotation signal. And a second determination means for determining the rotation direction of the engine from the change state of the crankshaft rotation signal, and the stop position estimation means uses either one of the two determination means. The engine stop position is estimated based on the specified rotation direction, and only when the engine rotation direction cannot be specified by both of these two determination means, What is necessary is just to estimate each stop position of the engine at the time of engine reverse rotation.

  Further, when a plurality of stop positions are estimated by the stop position estimating means when the engine is stopped, the first rotation position specifying means indicates that the change state of the cam shaft rotation signal input from the cam shaft sensor at the time of engine start is The engine rotation position may be specified when it coincides with one of the change states of the camshaft rotation signal when the engine is started at each of the plurality of stop positions. In this case, the engine stop position In some cases, the time required to specify the rotational position of the engine from a plurality of stop positions (in other words, the amount of engine rotation) becomes too large, and other rotational position specifying means (second or third rotational position specifying means) ) May clearly identify the rotational position of the engine.

  Therefore, in the engine control apparatus according to claim 4 or claim 5, the combination of the stop position, which requires a long time to specify the rotational position of the engine when starting the engine, is used to specify the rotational position of the engine. It is set in advance as an improper stop position, and when a plurality of stop positions are estimated by the stop position estimating means, the stop position estimation prohibiting means, as described in claim 6, It is determined whether or not the plurality of stop positions are preset stop positions that are preset as inappropriate for specifying the rotational position of the engine, and the plurality of stop positions are inappropriate for specifying the rotational position of the engine. If it is a stop position, the stop position estimation means forbids the estimation of the stop position, and the first rotational position specifying means is prohibited from specifying the rotational position of the engine at the next engine start. Then good.

  In this way, when a plurality of stop positions are estimated by the stop position estimating means when the engine is stopped, the plurality of stop positions are required to increase the time required to specify the rotational position when starting the engine. In the case of the position, unnecessary control operations by the stop position estimating means and the first rotational position specifying means are prohibited, and the control burden of the engine control device can be reduced.

  Hereinafter, an engine control apparatus according to an embodiment to which the present invention is applied will be described. The engine control apparatus according to the present embodiment controls a DOHC type in-line five-cylinder four-stroke one-cycle engine (so-called four-cycle engine).

  As shown in FIG. 1, the engine control apparatus according to the present embodiment includes a microcomputer 5 that executes processing for controlling the engine 3 and a drive circuit 7 that operates various actuators according to control signals from the microcomputer 5. And an electronic control device (hereinafter referred to as an engine ECU) 1 including an input circuit 9 for inputting various signals to the microcomputer 5.

  The microcomputer 5 of the engine ECU 1 includes a throttle opening sensor 17 that detects a signal from the intake air amount sensor 13 provided in the intake pipe 11 of the engine 3 and an opening degree of the throttle valve 15 provided in the intake pipe 11. , A signal from the intake pipe pressure sensor 19 that detects the pressure in the intake pipe 11, a signal from the pedal position sensor 23 that detects the operation position of the accelerator pedal 21 operated by the driver, and the coolant temperature of the engine 3 A signal from the water temperature sensor 25 for detecting the engine, a signal from the knock sensor 27 for detecting knocking of the engine 3, a signal from the oxygen concentration sensor 31 provided in the exhaust pipe 29 of the engine 3, and rotation of the crankshaft 33 In response, the crankshaft rotation signal (hereinafter referred to as the crank signal) output from the crankshaft sensor 35 and the intake valve are operated. An intake camshaft rotation signal (hereinafter referred to as an intake cam signal) output from an intake camshaft sensor 39 in response to the rotation of a camshaft (hereinafter referred to as an intake camshaft) 37, a camshaft (hereinafter referred to as an intake camshaft) that operates an exhaust valve. Exhaust camshaft rotation signal (hereinafter referred to as an exhaust cam signal) output from the exhaust camshaft sensor 43 according to the rotation of the exhaust 41, and various switches such as a vehicle ignition switch 45 and a starter switch (not shown) A switch signal indicating the on / off state of the signal is input via the input circuit 9.

  In addition, the microcomputer 5 detects the state of the engine 3 and the vehicle based on the above signals input via the input circuit 9, and outputs a control signal to the drive circuit 7 based on the detection result. A throttle motor 49 that changes the opening of the throttle valve 15, and an intake side variable valve timing mechanism 51 that changes the rotational phase difference of the intake camshaft 37 with respect to the crankshaft 33 (ie, the intake valve opening / closing timing) and the lift amount of the intake valve. An exhaust side variable valve timing mechanism 55 that changes the rotational phase difference of the exhaust camshaft 41 with respect to the crankshaft 33 (that is, the opening / closing timing of the exhaust valve) and the lift amount of the exhaust valve. Exhaust side oil control valve 57 for actuating the engine by hydraulic pressure, each cylinder Ignition coil 59 to ignite by energizing the spark plug, and the injector 61 of each cylinder, and controls the various actuators to operate the engine 3 such.

  On the other hand, a main relay 63 for power feeding is provided outside the engine ECU 1. When the ignition switch 45 is turned on, the main relay 63 is turned on, and the battery voltage ( The voltage VB of the plus terminal of the in-vehicle battery 67 is supplied. In the engine ECU 1, the respective parts such as the microcomputer 5, the drive circuit 7 and the input circuit 9 operate based on the battery voltage VB supplied to the power supply line 65.

  Also, the main relay 63 can be turned on / off by the microcomputer 5 via the drive circuit 7. Then, when the main relay 63 is turned on when the ignition switch 45 is turned on and starts to operate, the microcomputer 5 also turns on the main relay 63 itself, and then continues to operate even if the ignition switch 45 is turned off. When all necessary processes are completed, the main relay 63 is turned off to stop the operation. Such a power feeding technique using the main relay 63 is well known as described in, for example, Japanese Patent Application Laid-Open No. 11-259375.

  Here, the crankshaft sensor 35 is provided opposite to the outer periphery of the rotor 69 fixed to the crankshaft 33, and is formed on the outer periphery of the rotor 69 at intervals of a predetermined angle (6 ° in the present embodiment). It is a rotation sensor such as an electromagnetic pickup type or a Hall IC type that detects the tooth 71 and outputs a pulse that falls every time the tooth 71 passes. A crank signal that is a pulse train from the crankshaft sensor 35 is shaped into a rectangular waveform of high and low by the input circuit 9 and input to the microcomputer 5. In addition, one tooth missing portion having two missing teeth 71 is provided on the outer periphery of the rotor 69.

  Therefore, the crank signal input from the crankshaft sensor 35 to the microcomputer 5 via the input circuit 9 has an effective edge every 6 ° CA (every time the crankshaft 33 rotates 6 °) as shown in FIG. When the rotation position of the crankshaft 33 is at a reference position where the tooth missing portion of the rotor 69 faces the crankshaft sensor 35, the interval between the falling edges is 3 The missing tooth portion K having a double length (that is, a length corresponding to 18 ° CA) appears. The tooth missing portion of the rotor 69 may also be called “missing tooth portion” or simply “missing tooth”, and the missing tooth portion K of the crank signal may also be simply called “missing tooth”.

  Further, in this embodiment, as shown in FIG. 2, each cylinder of the engine 3 is in the order of the first cylinder # 1, the second cylinder # 2, the fourth cylinder # 4, the fifth cylinder # 5, and the third cylinder # 3. The TDC (top dead center) is in turn, and the missing tooth portion K of the crank signal has a period of BTDC 30 ° CA to BTDC 12 ° CA of the fourth cylinder # 4 and a period of ATDC 42 ° CA to ATDC 60 ° CA of the third cylinder # 3. And it comes to appear. “BTDC” means “before top dead center”, and “ATDC” means “after top dead center”.

  On the other hand, the intake camshaft sensor 39 is provided facing the outer periphery of a rotor (not shown) fixed to the intake camshaft 37, and the level of the output signal is high according to the unevenness formed on the outer periphery of the rotor. A magnetoresistive element (MRE) type rotation sensor that changes between low and high, and an intake cam signal output from the intake camshaft sensor 39 is also subjected to waveform shaping by the input circuit 9 and input to the microcomputer 5.

  Then, the intake cam signal input from the intake camshaft sensor 39 to the microcomputer 5 via the input circuit 9 changes in level for one cycle (one revolution of the intake camshaft 37 and two revolutions of the crankshaft 33). As shown in FIG. 2, for example, the pattern is described with the falling edge immediately before the TDC of the fourth cylinder # 4 as a starting point, “120 ° CA minute: low → 24 ° CA minute: high → 90 ° CA minute: Low → 54 ° CA min: High → 60 ° CA min: Low → 84 ° CA min: High → 48 ° CA min: Low → 96 ° CA min: High → 18 ° CA min: Low → 126 ° CA min: High In other words, the pattern does not include a plurality of portions having a width corresponding to the same crank angle. Each falling edge of the intake cam signal is generated at a timing of BTDC 33 ° CA of each cylinder. Further, the intake cam signal has a level alternately different at each timing at the end timing of the missing tooth portion K in the crank signal. Specifically, it becomes low level at the timing of BTDC 12 ° CA of the fourth cylinder # 4 and becomes high level at the timing of ATDC 60 ° CA of the third cylinder # 3.

  Similarly, the exhaust camshaft sensor 43 is also provided opposite to the outer periphery of a rotor (not shown) fixed to the exhaust camshaft 41, and the level of the output signal is determined according to the irregularities formed on the outer periphery of the rotor. Is a magnetoresistive element type rotation sensor that changes between high and low. The exhaust cam signal output from the exhaust cam shaft sensor 43 is also shaped by the input circuit 9 and input to the microcomputer 5.

  Then, the level change of one cycle of the exhaust cam signal input to the microcomputer 5 from the exhaust cam shaft sensor 43 via the input circuit 9 (one rotation of the exhaust cam shaft 41 and two rotations of the crank shaft 33). As shown in FIG. 2, for example, when the rising edge immediately before the TDC of the fourth cylinder # 4 is described as a starting point, the pattern is “102 ° CA minutes: high → 18 ° CA minutes: low → 144 ° CA minutes: high. → 120 ° CA min: Low → 18 ° CA min: High → 60 ° CA min: Low → 72 ° CA min: High → 72 ° CA min: Low → 102 ° CA min: High → 42 ° CA min: Low It is a pattern that. Of the edges of the exhaust cam signal, the rising edge immediately before the TDC of the fourth cylinder # 4 (the rising edge transitioning from “42 ° CA min: low” to “102 ° CA min: high”) is the fourth. It occurs at the timing of BTDC 78 ° CA of cylinder # 4.

  In FIG. 2, the numbers described above the arrows attached to the waveforms of the intake cam signal and the exhaust cam signal indicate the crank angle during the period of the arrows. In FIG. 1, the input circuit 9 is collectively shown as one, but the input circuit 9 actually exists for each input signal input to the microcomputer 5, and the type of each input signal The signal processing according to is performed. For example, if the input signal is a crank signal, an intake cam signal, an exhaust cam signal, or a switch signal, the signal is waveform-shaped and input to the microcomputer 5, and the signal from the intake air amount sensor 13 or the water temperature sensor 25 is input. If the signal is an analog signal, the high frequency noise is removed from the signal and input to the input port for the A / D converter of the microcomputer 5. Similarly, the drive circuit 7 actually exists for each actuator.

  In the engine ECU 1 having the hardware configuration described above, the microcomputer 5 determines the rotational position per cycle of the engine 3 from 0 ° CA to 720 ° based on the crank signal, the intake cam signal, and the exhaust cam signal. While specifying as the crank position of CA, the value of the crank counter referred to for recognizing the crank position in the microcomputer 5 is updated as shown in FIG.

  The value of the crank counter is shown by a solid line in FIG. 2 so that the resolution is 36 ° CA and lap round in the range of 0 to 19, but actually, as shown in the dotted ellipse, The resolution of the crank counter is 6 ° CA. That is, the value of the crank counter is wrapped round in a range of 0 to 119 with a resolution of 6 ° CA. The crank position at the timing when the value of the crank counter returns from the maximum 119 to the minimum 0 is BTDC 6 ° CA of the fourth cylinder # 4. The microcomputer 5 sets the timing of ignition and fuel injection for the engine 3 based on the value of the crank counter.

  Next, processing executed by the microcomputer 5 to identify the crank position will be described with reference to flowcharts shown in FIGS. The microcomputer 5 is a memory 6 for storing data. In addition to a normal RAM, the memory 5 can continuously hold data even when the operation of the engine ECU 1 when the battery voltage VB is not supplied to the power line 65 is stopped. (In this embodiment, the RAM is a power-backed up RAM, but may be a non-volatile rewritable memory such as a flash ROM or EEPROM, for example.) Otherwise, the information storage destination is a normal RAM. Also, the information stored in the normal RAM is cleared by initialization processing for the RAM when the microcomputer 5 starts its operation when the ignition switch 45 is turned on, or set to another initial value.

  First, FIG. 3 is a flowchart showing a crank signal interruption process executed every time a falling edge as an effective edge occurs in the crank signal. However, in this crank signal interruption process, during the starter mask period from when the starter switch is turned on and the cranking of the engine 3 by the starter is started until a predetermined time elapses, a large noise due to the starter operation is added to the crank signal. Execution is prohibited because there is a high possibility that

  As shown in FIG. 3, when the microcomputer 5 starts the crank signal interrupt process, first, in S110 (S represents a step), the time from the time when the crank signal interrupt process was started to the time when it started this time is calculated. The calculated time is stored as a pulse interval of the crank signal. When this process is executed only after the ignition switch 45 is turned on and the microcomputer 5 starts operating, the maximum value as the initial value is stored as the pulse interval.

  Next, in S120, the pulse interval memorized this time in S110 (ie, the current pulse interval of the crank signal) T1 is compared with the pulse interval memorized last in S110 (ie, the previous pulse interval of the crank signal) T0. Then, it is determined whether the missing tooth determination condition that the ratio of T1 to T0 (= T1 / T0) is equal to or greater than a predetermined determination ratio H (for example, H = 2.4) is satisfied. When the tooth determination condition is satisfied, it is determined that a missing tooth portion K appears in the crank signal (specifically, the falling edge of the current crank signal is the end timing of the missing tooth portion K), Subsequently, the process proceeds to S130. Conversely, if the missing tooth determination condition is not satisfied, the process proceeds to S150.

  When this processing is executed only after the ignition switch 45 is turned on and the microcomputer 5 starts operating, T0 is set to the maximum value as an initial value. In this case, in S120 Therefore, it is always determined that the missing tooth determination condition is not satisfied.

  Next, in S130 executed when the missing tooth determination condition is satisfied, the current intake cam signal level is checked, and in subsequent S140, the crank counter is set in accordance with the intake cam signal level checked in S120. Set the value. Specifically, if the intake cam signal is at a low level, it can be determined that the current crank position is BTDC 12 ° CA of the fourth cylinder # 4, so that the crank counter is set to 119 (that is, one before returning to 0). Value) and the intake cam signal is at a high level, it can be determined that the current crank position is ATDC 60 ° CA of the third cylinder # 3, so the crank counter is set to 59 (ie, 119 to 360 ° CA minutes). (Value shifted by 60). In S140, after setting the value 119 or 59 in the crank counter, the process proceeds to S150.

  In S150, it is determined whether or not the crank position has been specified. If the crank position has been specified, the process proceeds to S160. Conversely, if the crank position has not been specified, the crank signal interruption process is terminated. To do.

  Note that the crank position has already been specified means that the crank position has already been specified after the microcomputer 5 has started to operate with the ignition switch 45 turned on, and more specifically, the crank position has been specified. The corresponding value can be set in the crank counter, and the value of the crank counter has already become a value indicating the crank position. In the present embodiment, after the microcomputer 5 starts operating, if a value is set in the crank counter in the process of S140 described above or the process of S340 or S360 of FIG. The crank position has already been specified.

  Next, in S160, it is determined whether or not the missing tooth portion K appears in the crank signal by referring to the determination result in S120. If the missing tooth portion K appears in the crank signal, the process proceeds to S180. On the contrary, if the missing tooth portion K does not appear in the crank signal, the crank counter is counted in S170, and then the process proceeds to S180. In S170, basically, an increment process for increasing the value of the crank counter by 1 is performed, but when the value before the increase is 119, a lap round process for returning the value to 0 is performed. Further, in S170, when the counting direction is reversed by the processing of S250 described later, it is assumed that the engine 3 is immediately before stopping and is rotating in the direction opposite to that during normal operation. Decrement processing for decreasing the value by 1 is performed.

  In S180, it is determined whether or not the ignition switch (IGSW) 45 is turned on, that is, whether or not the engine 3 is in operation. If the ignition switch (IGSW) 45 is currently turned on and the engine 3 is in operation, the process proceeds to S190, and the current crank position is based on BTDC 6 ° CA of the fourth cylinder # 4. It is determined whether or not the crank position is every 36 ° CA (that is, whether or not the current crank counter value is an integer multiple of 6 (= 0, 6, 12,..., 108, 114)). If the crank position is not every 36 ° CA, the crank signal interruption process is terminated as it is. If the crank position is every 36 ° CA, the subsequent steps S200 and S210 are executed, and then the crank signal interruption process is performed. Exit.

  In S200, a control process for controlling the ignition and fuel injection of each cylinder is started, and in the subsequent S210, another angle synchronization control process to be executed every 36 ° CA is started. As a result, various control amounts such as the ignition timing, fuel injection amount, and injection timing of the engine 3 are calculated, and a timer set for performing ignition and fuel injection is performed.

  On the other hand, if it is determined in S180 that the ignition switch (IGSW) 45 is not turned on, it is determined in S220 whether or not the engine speed is equal to or less than a predetermined value TH0. It is determined whether or not is moving from the operating state to the stopped state. The engine speed is calculated based on the pulse interval of the crank signal that is sequentially updated and stored in S110 described above. The predetermined value TH0 is set to an engine speed lower than the idle speed, for example, 500 rpm.

  If it is determined in S220 that the engine speed is higher than the predetermined value TH0, the crank signal interruption process is terminated as it is, and conversely, it is determined that the engine speed is equal to or lower than the predetermined value TH0. If the engine 3 has shifted to S230, whether or not the rotation direction of the engine 3 has been reversed based on the pulse interval of the crank signal sequentially updated and stored in S110 described above (that is, the engine 3 has rotated in the reverse direction). Whether or not).

  That is, when the engine 3 is stopped, the top dead center (TDC) cannot be exceeded in the cylinder in the compression stroke immediately before the stop, and the engine 3 may rotate in the opposite direction to that during normal operation. In S230, it is determined whether or not the rotation direction of the engine 3 has been reversed by determining whether or not the pulse interval has suddenly increased based on the past history of the pulse interval of the crank signal that is sequentially updated and stored in S110. Judgment is made.

  If the rotation direction of the engine 3 is reversed when the engine 3 is stopped in this way, the value of the crank counter updated in the counting process of S170 will not correspond to the actual crank position of the engine 3. If it is determined in S230 that the rotation direction of the engine 3 has been reversed, the process proceeds to S240, where the value of the crank counter is updated according to the rotation direction at that time, and in the subsequent S250, in the count process of S170 After inverting the count direction of the crank counter in the reverse direction, the crank signal interruption process is terminated. If it is determined in S230 that the rotation direction of the engine 3 is not reversed, the crank signal interruption process is terminated as it is.

Next, FIG. 4 is a flowchart showing cam signal interruption processing that is executed every time an edge occurs in either the intake cam signal or the exhaust cam signal.
As shown in FIG. 4, when the microcomputer 5 starts the cam signal interrupt processing, first, in S300, the type of the cam signal used this time for starting the interrupt processing and its edge direction (rising or falling) are stored. In subsequent S310, it is determined whether or not the ignition switch (IGSW) 45 is turned on. If it is determined in S310 that the ignition switch 45 is turned on, the process proceeds to S320, and it is determined whether or not the engine speed is equal to or less than a predetermined value TH1.

  The predetermined value TH1 is a rotational speed at which the engine 3 is considered to be operating under the control of the engine ECU 1, and is set to, for example, 500 rpm which is slightly lower than the idle rotational speed in the present embodiment. Further, the engine speed is calculated based on the pulse interval of the crank signal that is sequentially updated and stored in S110 of FIG.

  Next, when it is determined in S320 that the engine speed is equal to or less than the predetermined value TH1, that is, when the engine 3 is currently just started, the process proceeds to S330, and conversely, in S320. If it is determined that the engine speed exceeds the predetermined value TH1, after initialization for deleting the estimated stop position, which is the estimated value of the stop position of the crankshaft 33, from the memory 6 is performed in S390. Then, the cam signal interruption process is terminated. The estimated stop position value is data that is calculated when the engine 3 is stopped by a stop position estimation process 400 described later and stored in the memory 6.

  Next, in S330, it is determined whether or not the crank position has already been specified, as in S150 of FIG. If it is determined in S330 that the crank position has not been specified, cylinder determination processing (see FIG. 6) based on the cam signal is executed in subsequent S340, and then the process proceeds to S350. If it is determined that the crank position has been specified, the process proceeds to S350.

  In S350, as in S330 and S150 in FIG. 3, it is determined whether or not the crank position has been specified. If it is determined in S350 that the crank position has not been specified, then in S360, a crank position specifying process based on the estimated stop position (see FIG. 7) is executed, and then the cam signal interrupt process is performed. On the contrary, if it is determined in S350 that the crank position has already been specified, the cam signal interruption process is ended as it is.

  If it is determined in S310 that the ignition switch (IGSW) 45 is not turned on, that is, the ignition switch (IGSW) 45 is turned off, and the engine 3 is currently shifting from the operating state to the stopped state. If there is, the process proceeds to S400, where a stop position estimation process (see FIG. 5) for estimating the stop position of the engine 3 is executed, and the cam signal interrupt process ends.

  When the microcomputer 5 is activated by turning on the ignition switch (IGSW) 45, the microcomputer 5 repeatedly executes each of the above interrupt processing. After the activation, the ignition switch (IGSW) 45 is turned off. When it is detected that the cam signal and the exhaust cam signal all do not change in level for a certain time or longer, it is determined that the engine 3 has completely stopped, the main relay 63 is turned off, and its operation is stopped. To do.

Next, the stop position estimation process executed in S400 of FIG. 4 when the engine 3 is stopped will be described.
As shown in FIG. 5, in this stop position estimation process, first, in S500, the estimation prohibition flag F that is reset (= 0) when the microcomputer 5 is started and set (= 1) in the process of S650 described later is It is determined whether or not it is set (= 1). If the estimation prohibition flag F is set, the stop position estimation process is terminated as it is. Conversely, if the estimation prohibition flag F is not set, the process proceeds to S510 and the same as S220 in FIG. Then, it is determined whether or not the engine speed is equal to or less than a predetermined value TH0.

  Next, when it is determined in S510 that the engine speed is not equal to or less than the predetermined value TH0, the stop position estimation process is terminated as it is, and in S510, the engine speed is equal to or less than the predetermined value TH0. If it is determined, the process proceeds to S520, and it is determined whether or not the stop position estimated value is stored in the memory 6.

  When it is determined in S520 that the estimated stop position value is not stored in the memory 6, the process proceeds to S530, on the basis of the value of the crank counter updated in the crank signal interruption process of FIG. Then, after setting the initial value of the estimated stop position and storing the value in the memory 6, the stop position estimation process is terminated.

  Note that the estimated stop position represents the crank position when the engine 3 is stopped. In this embodiment, the edge of the intake cam signal or the exhaust cam signal used this time to start the cam signal interrupt processing is detected. 2 is discriminated as one of the 20 edge numbers E1 to E20 shown in FIG. 2, and the edge number is stored in the memory 6 as a stop position estimated value.

  On the other hand, if it is determined in S520 that the stop position estimated value is stored in the memory 6, the process proceeds to S540 and the stop position estimated value is updated. This update process is basically performed by incrementing (+1) the edge number. When the edge number is E20, the stop position estimated value is updated by returning the edge number to the minimum value E1. Is done. Further, when the update direction of the stop position estimated value is set in the reverse direction to the normal time in the processing of S590 described later, in S540, the stop position is estimated by decrementing the edge number (−1). The value is updated, and when the edge number is E1 during the updating operation, the stop position estimated value is updated by returning the edge number to the maximum value E20.

  Thus, when the estimated stop position is updated in S540, the edge direction of the cam signal stored this time in S300 of FIG. 4 is compared with the edge direction of the previously stored cam signal in S550. Thus, it is determined whether the rotation direction of the engine 3 is the normal rotation direction that is the rotation direction during engine operation or the reverse rotation direction opposite to the normal rotation direction.

  That is, as is apparent from FIG. 2, the cam signal input to the microcomputer 5 during the forward rotation of the engine 3 has its input order and edge direction determined. When the engine 3 rotates backward, In S550, the type and edge direction of the cam signal used this time to start the cam signal interrupt process and the previous cam signal are changed. By comparing the type and the edge direction, it is determined whether the engine 3 is rotating forward or backward.

  Further, for example, when the crank position enters between the edge numbers E5 and E6 in FIG. 2 due to the normal rotation of the engine 3, and the stop position estimated value is stored as the edge number E5, the rising edge of the intake cam signal is Since there is a region where the rotation direction of the engine 3 cannot be identified only by the edge of the cam signal used for starting the cam signal interrupt processing as when the cam signal interrupt processing is input and started, in the subsequent S560, It is determined whether or not the rotation direction of the engine 3 has been identified in the determination process of S550.

  If it is determined in S560 that the rotation direction of the engine 3 has been identified, the process proceeds to S570, and whether or not the rotation direction of the engine 3 has been reversed based on the determination result in S550 (that is, the engine 3). 3, and if it is determined in S570 that the rotation direction of the engine 3 has been reversed, the process proceeds to S580 and is stored in the memory 6 according to the rotation direction at that time. In step S590, after the stop position estimated value is corrected, the update direction of the stop position estimated value in the update process of the stop position estimated value in S540 is reversed in the reverse direction, and then the stop position estimated process is performed. Exit. If it is determined in S570 that the rotation direction of the engine 3 is not reversed, the stop position estimation process is terminated as it is.

  On the other hand, if it is determined in S560 that the rotation direction of the engine 3 could not be identified, the process proceeds to S600, and the engine 3 assumes that the current position is in addition to the estimated stop position updated in S540. The estimated stop position when rotating in the direction opposite to the rotating direction is added as a so-called candidate. In other words, when the estimated stop position value is updated in S540 because the engine 3 is rotating in the forward rotation direction, the estimated stop position is updated in S600 assuming that the engine 3 is rotating in the reverse rotation direction. The value is added as a new candidate for the estimated stop position.

  When the stop position estimated value is added in S600, it is determined in subsequent S610 whether the stop position of the engine 3 can be estimated from the value of the crank counter. That is, in this embodiment, even in the crank signal interruption process shown in FIG. 3, it is determined whether or not the rotation direction of the engine 3 is reversed when the engine 3 is stopped (S230), and the crank counter is set based on the determination result. Since the engine is updated (S240), in S610, the rotation direction of the engine 3 is determined in the crank signal interruption process to determine whether or not the crank counter has been correctly updated. It is determined whether or not the stop position 3 can be estimated.

  When it is determined in S610 that the stop position (that is, the crank position) of the engine 3 can be estimated from the value of the crank counter, the process proceeds to S620, and one stop position estimated value is specified from the value of the crank counter. And the said stop position estimation process is complete | finished.

  On the other hand, if it is determined in S610 that the stop position of the engine 3 cannot be estimated from the value of the crank counter, the process proceeds to S630, and the plurality of estimated stop position values currently stored in the memory 6 are When the engine is started, it is determined whether the value is set in advance as an estimated value inappropriate for specifying the rotational position (crank position) of the engine.

  If it is determined in S630 that the plurality of stop position estimated values currently stored in the memory 6 are not inappropriate estimated values (estimated value OK), the stop position estimating process is terminated as it is. On the other hand, if it is determined that the plurality of estimated stop position values currently stored in the memory 6 are inappropriate estimated values, the estimated stop position values are deleted from the memory 6 in S640. After initialization, in S650, the estimation prohibition flag F is set, and the stop position estimation process ends.

  The estimated value inappropriate for specifying the rotational position (crank position) of the engine 3 at the next engine start is the crank value using a plurality of stop position estimated values stored in the memory 6 at the engine start. If the position is specified, the crank position specifying process in S360 must be executed many times, and the time until the crank position can be specified when the engine is started is determined by the crank signal interrupt process or the cam signal interrupt process. Represents the estimated stop position, which is longer than the time for which the crank position is specified in the cylinder discrimination process in S340.

  In other words, when a plurality of estimated stop position values are stored in the memory 6, the cam signal input from the intake camshaft sensor 39 and the exhaust camshaft sensor 43 at the time of engine start in the crank position specifying process of S 360. The edge is monitored, and it is finally determined whether or not the edge coincides with the edge to be input when the engine 3 is started from the crank position corresponding to each estimated stop position value. In addition, the crank position updated from one estimated value of the stop position is specified as the current rotational position of the engine 3. The number of processing until the crank position can be specified in the crank position specifying process is stored in the memory 6. The number of executions of the crank position specifying process varies depending on the stored stop position estimation value and, depending on the combination of a plurality of stop position estimation values, In this embodiment, a combination of such stop position estimated values is registered in advance, and a plurality of stop position estimated values stored in the memory 6 are used as the registered stop position estimated values. When the values match, the stop position estimation operation itself is prohibited, and at the next engine start, the crank position is specified by the crank signal interruption process or the cylinder discrimination process of S340 in the cam signal interruption process. It is.

Next, the cylinder discrimination process that is executed in S340 of FIG. 4 when the crank position is not specified when the engine 3 is started will be described.
As shown in FIG. 6, in this cylinder discrimination process, first, in S710, based on the cam signal type and edge direction stored in S300, the start of the current cam signal interrupt process is performed by the rising edge of the intake cam signal. It is judged whether it is a thing.

  In S710, if it is determined that the start of the cam signal interrupt process this time is due to the rising edge of the intake cam signal, the process proceeds to S715, and the above-described starter mask period has passed (hereinafter, “ If the starter mask has been released, the rising (or falling) edge of the crank signal input from the crankshaft sensor 35 is counted in S720. After starting a count process (not shown), the cylinder discrimination process is terminated. Conversely, if the starter mask is not released, the cylinder discrimination process is terminated as it is.

  On the other hand, if it is determined in S710 that the start of the current cam signal interrupt process is not due to the rising edge of the intake cam signal, the process proceeds to S730, and this time the start of the cam signal interrupt process is performed. Determines whether it is due to the falling edge of the intake cam signal.

  In S730, if it is determined that the start of the cam signal interrupt process this time is not due to the falling edge of the intake cam signal, the cylinder discrimination process is terminated as it is. If not, the process proceeds to S735. By the process of S720, it is determined whether or not the crank signal counting process is currently being executed.

  If the crank signal counting process has not yet been executed, the cylinder discrimination process is terminated. Conversely, if the crank signal counting process has been executed, the routine proceeds to S740, where the intake cam signal rises. The rotational position (crank position) of the engine 3 is specified from the count value of the rising (or falling) edge of the crank signal that started counting in S720 when the edge is input.

  In other words, in this embodiment, the falling edge of the intake cam signal is generated at the timing of BTDC 33 ° CA of each cylinder, and after the intake cam signal rises, the period until the next fall (crank) Since the angle is set to a different period (crank angle) for each cylinder, in this cylinder discrimination process, the edge of the crank signal is counted during the period from when the intake cam signal rises once and then falls The crank position of the engine 3 is specified based on the count value.

  Thus, when the crank position of the engine is specified in S740, the process proceeds to S750, in which a value corresponding to the crank position specified in S740 is set in the crank counter to determine the cylinder. End the process. If a value is set in the crank counter in S750, then the cylinder position identification process and a crank position identification process described later are prohibited, assuming that the crank position has been identified.

Next, the crank position specifying process executed in S360 of FIG. 4 when the crank position is not specified when the engine 3 is started will be described.
As shown in FIG. 7, in this crank position specifying process, first, in S810, it is determined whether or not a stop position estimated value is stored in the memory 6, and if the stop position estimated value is stored in the memory 6, as shown in FIG. In S820, it is determined whether or not the cam signal used to start the cam signal interrupt process this time and the edge direction thereof correspond to the estimated stop position value stored in the memory 6.

  In other words, the estimated stop position is an edge number that represents the edge of the cam signal that has passed last when the engine 3 is stopped at the normal rotation. From the edge number, the cam signal to be input next when the engine is started and Since the edge direction can be specified, in S820, it is stored in the memory 6 by determining whether or not the estimated stop position value stored in the memory 6 corresponds to the edge of the cam signal input this time. It is determined whether or not the estimated stop position value (at least one of the stored stop position values is coincident with the actual rotational position of the engine 3).

  If it is determined in S820 that the estimated stop position values stored in the memory 6 (if a plurality of stop position values are stored, all of them) do not match the actual rotational position of the engine 3 In step S830, the memory 6 is initialized by deleting all the estimated stop position values stored in the memory 6, and the crank position specifying process ends.

  On the other hand, in S820, it is determined that the estimated stop position value stored in the memory 6 (at least one of the stored stop position values if it is stored) matches the actual rotational position of the engine 3. If this is the case, in S840, a plurality of estimated stop position values are stored in the memory 6, and it is determined whether any one of them is not coincident with the actual rotational position of the engine 3. to decide.

  If the estimated stop position value that does not coincide with the actual rotational position of the engine 3 is stored in the memory 6, the process proceeds to S850, and initialization processing for deleting the estimated stop position value from the memory 6 is performed. , The process proceeds to S860. Conversely, if the memory 6 does not store the estimated stop position that does not match the actual rotational position of the engine 3, the process proceeds to S860 as it is.

  Next, in S860, it is determined whether or not the above-described starter mask period has passed (hereinafter referred to as “starter mask is released”). If the starter mask is released, the process proceeds to S870, where It is determined whether or not there is only one stop position estimated value stored in the memory 6.

  In S870, it is determined that there is not one stop position estimated value stored in the memory 6 (that is, a plurality of stop position estimated values), or in S860, it is determined that the starter mask has not been released. In S 880, the estimated stop position value stored in the memory 6 is updated by the value 1 along the forward rotation direction of the engine 3 in S 880, and then the crank position specifying process is terminated.

  On the other hand, if it is determined in S870 that there is only one stop position estimated value stored in the memory 6, the process proceeds to S890, where the crank position is determined based on the stop position estimated value stored in the memory 6. A value representing the current crank position is set in the counter, and the crank position specifying process ends.

  For example, when the edge number E1 is stored as the estimated stop position in the memory 6, the current cam signal interruption process is started by the edge of the next edge number E2, and therefore the crank counter A value representing the crank position corresponding to the edge of the edge number E2 is set, whereby the first crank position at the time of engine start is specified. When a value is set in the crank counter in S890, the crank position specifying process and the cylinder determining process are prohibited after that, assuming that the crank position has been specified.

  As described above, in this embodiment, when the engine is started, the crank position that is the rotational position of the engine 3 is specified and the value is set in the crank counter. In addition to the crank counter setting process (S140), a cylinder discrimination process (S340) based on the cam signal in the cam signal interrupt process, and a crank position specifying process (S360) based on the estimated stop position in the cam signal interrupt process. When the value is set in the crank counter in any of these processes, the engine control is started while the crank counter value is updated in the crank signal interruption process, and the value is set in the crank counter. After that, assuming that the crank position has been specified, the crank position specifying process (S360) and the It is adapted to prohibit the execution of the determination process (S340).

  Therefore, according to the engine control apparatus of the present embodiment, the three types of crank position specifying methods using the missing tooth portion K of the crank signal, the change pattern of the intake cam signal, or the estimated stop position estimated when the engine is stopped. The engine control can be started using the one that can identify the crank position earliest, and the engine control start timing can be made earlier.

  In the present embodiment, when the engine is stopped, the engine 3 may reversely rotate without exceeding the top dead center (TDC) in the cylinder in the compression stroke. When estimating the stop position of the engine 3, the rotational direction of the engine 3 is determined (S550), and the engine stop position is estimated according to the determination result. Even if it determines, a stop position can be estimated correctly.

  In the present embodiment, the determination of the rotation direction when the engine is stopped is performed not only in the stop position estimation process performed in the cam signal interrupt process but also in the crank signal interrupt process (S230). When the engine rotation direction cannot be identified from the cam signal, the stop position is estimated using the crank counter value updated according to the rotation direction determined based on the crank signal in the crank signal interruption process. Therefore, the estimation accuracy of the stop position can be increased.

  Furthermore, in the present embodiment, not only in the stop position estimation process but also in the crank signal interruption process, when the rotation direction of the engine 3 at the time of engine stop cannot be accurately identified, the stop position when the engine 3 rotates forward is determined. Each stop position when the engine 3 rotates in reverse is estimated (S600), and when the engine is started, the rotation position (crank position) of the engine 3 is specified based on the estimated stop position values in the crank position specifying process. Therefore, when starting the engine, the crank position can be specified using the estimated stop position.

  In the present embodiment, when the engine is started, the rotation position (crank position) of the engine 3 can be specified not only by the crank position specifying process but also by the crank signal interruption process and the cylinder discrimination process. When the estimated plurality of stop positions are stop positions that take a long time to specify the crank position in the crank position specifying process, the estimation operation by the stop position estimating process and the crank position specifying process at the time of starting the engine This operation is prohibited (S640, S650). For this reason, according to the present embodiment, unnecessary calculation operations in the microcomputer 5 can be prohibited and the processing load on the microcomputer 5 can be reduced.

In this embodiment, the stop position estimation process (FIG. 5) in the cam signal interrupt process corresponds to the stop position estimation means of the present invention, and the crank position specifying process (FIG. 7) is also the first rotation of the present invention. Corresponding to the position specifying means, the cylinder discrimination process (FIG. 6) corresponds to the third rotational position specifying means of the present invention (specifically, described in claim 3) , and the crank signal in the crank signal interruption process (FIG. 3). The processing of S120 to S140 that is executed to set the crank counter based on the missing tooth portion corresponds to the second rotational position specifying means of the present invention (specifically, described in claim 1) .

  Further, the processing of S550 and S230 for determining the rotation direction of the engine 3 in the stop position estimation processing and the crank signal interruption processing corresponds to the rotation direction determination means of the present invention. Of these, the processing of S550 in particular is the first It corresponds to a determination unit, and the process of S230 corresponds to a second determination unit. The processes of S630 to S650 and S500 executed to prohibit the estimation of the stop position in the stop position estimation process correspond to the stop position estimation prohibiting means of the present invention.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to such Embodiment, A various aspect can be taken within the technical scope of this invention.
For example, in the above-described embodiment, the rotational position (crank position) of the engine 3 at the time of engine start is determined by the crank position specifying process in the cam signal interrupt process, the cylinder determination process, and the crank signal interrupt process. When the crank position can be identified earliest in any of these three processes, engine control based on the crank position is started, but the rotational position of the engine 3 is identified when the engine is started. There are two processes, a crank position specifying process and a crank signal interruption process, or a crank position specifying process and a cylinder determining process.

  In the above embodiment, the stop position when the engine is stopped is described as being estimated based on the edge of the intake cam signal and the exhaust cam signal in the cam signal interruption process. May be used for estimation, or the stop position when the engine is stopped may be estimated using only the value of the crank counter updated in the crank signal interruption process.

  Further, when the stop position when the engine is stopped is estimated based on the edge of the intake cam signal or the exhaust cam signal as in the above embodiment, the edge of the cam signal is increased as the number of cylinders of the engine 3 increases. However, it is necessary to shorten the edge interval. To this end, it is necessary to complicate the shape of the camshaft sensor and to increase the accuracy of assembly of the camshaft sensor with respect to the camshaft. I will invite you.

  Therefore, in order to prevent such problems, to simplify the shape of the camshaft sensor, and to ensure that the assembly accuracy to the camshaft is not required, the stop position when the engine is stopped is determined by combining the cam signal and the crank signal. You may make it estimate using. That is, for example, in the above embodiment, when the engine is stopped, the stop position is roughly estimated using the edge of the intake cam signal, and the estimated engine stop position is estimated by counting the crank signal. By doing so, the stop position of the engine 3 can be accurately estimated without complicating the shape of the camshaft sensor or increasing the accuracy with which the camshaft sensor is assembled to the camshaft.

  In the above embodiment, when the stop position of the engine 3 is estimated, the rotation direction of the engine 3 is determined based on the change in the edge direction of the cam signal in the processing of S550 to S650 in FIG. Although the stop position estimated value is corrected according to the rotation direction when rotating, and further, when the rotation direction cannot be accurately determined, the stop position estimated value candidate is added according to each rotation direction. If the camshaft sensor is formed so that the cam signal edge does not occur even if the engine 3 rotates reversely just before stopping, such processing can be eliminated.

  That is, in the above-described embodiment, the cam signal edge is input when the engine 3 rotates in reverse. The camshaft sensors 39 and 43 detect the cam signal edge immediately before the top dead center of each cylinder of the engine 3. Therefore, for example, the cam shaft sensor is formed so that the edge of the cam signal is generated at the top dead center of each cylinder of the engine 3 or the position after the top dead center. If so, the processing of S550 to S650 in FIG. 5 can be made unnecessary.

  Further, in the above embodiment, the engine control is not started until the starter mask period in which noise is expected to be added to the crank signal is passed. However, during the starter mask period, fuel injection is performed with a time timer. According to this configuration, even during the starter mask period, engine control can be started from the time when the rotational position (crank position) of the engine 3 is specified by the crank position specifying process or the cylinder determining process.

  In the above embodiment, the stop position of the engine 3 is estimated using the two cam shaft rotation signals of the intake cam signal and the exhaust cam signal, and the rotation position (crank position) of the engine 3 is specified. However, the present invention can be applied even when only one camshaft rotation signal is input in addition to the crank signal.

  In the above embodiment, the reference position is detected by providing the rotor 69 of the crankshaft 33 with a missing tooth (tooth missing portion). However, the configuration of the rotor 69 for detecting the reference position is as described above. It is not limited to the configuration in which the missing teeth are provided, but other tooth-shaped configurations (for example, a configuration in which so-called additional teeth and extra teeth are provided, and the protrusion (tooth) is longer than the other in one place in reverse of the missing teeth, etc. Or a discontinuous portion).

It is a block diagram showing the structure of the whole engine control apparatus of embodiment. It is a time chart showing the relationship between a crank signal, an intake cam signal, an exhaust cam signal, and a crank counter. It is a flowchart showing a crank signal interruption process. It is a flowchart showing a cam signal interruption process. It is a flowchart showing a stop position estimation process. It is a flowchart showing the cylinder discrimination | determination process based on a cam signal. It is a flowchart showing the crank position specific process based on a stop position estimated value.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine ECU, 3 ... Engine, 5 ... Microcomputer, 6 ... Memory, 7 ... Drive circuit, 9 ... Input circuit, 11 ... Intake pipe, 13 ... Intake air amount sensor, 15 ... Throttle valve, 17 ... Throttle opening sensor , 19 ... Intake pipe pressure sensor, 21 ... Accelerator pedal, 23 ... Pedal position sensor, 25 ... Water temperature sensor, 27 ... Knock sensor, 29 ... Exhaust pipe, 31 ... Oxygen concentration sensor, 33 ... Crankshaft, 35 ... Crankshaft sensor 37 ... Intake camshaft, 39 ... Intake camshaft sensor, 41 ... Exhaust camshaft, 43 ... Exhaust camshaft sensor, 45 ... Ignition switch, 49 ... Throttle motor, 51 ... Intake side variable valve timing mechanism, 53 ... Intake side Oil control valve, 55 ... Exhaust side variable valve timing mechanism, 57 ... Exhaust side oil control valve, 59 ... Ignition coil 61 ... Injector, 63 ... main relay, 65 ... power supply line, 67 ... vehicle battery, 69 ... rotor, 71 ... teeth, K ... toothless portion.

Claims (6)

A camshaft sensor that is provided on the camshaft of the engine and generates a camshaft rotation signal that changes according to the rotational position of the camshaft;
A crankshaft sensor that is provided on the crankshaft of the engine and generates a crankshaft rotation signal at every predetermined rotation angle of the crankshaft;
Stop position estimating means for estimating a rotation stop position of the engine based on at least one of the camshaft rotation signal and the crankshaft rotation signal when the engine stops from the operating state;
First rotational position specifying means for specifying a rotational position per one engine cycle based on the stop position estimated by the stop position estimating means and the camshaft rotation signal when the engine is started;
When the engine rotation position is specified by the first rotation position specifying means, engine control based on the rotation position is started, and then the engine rotation position is updated based on the crankshaft rotation signal. An engine control device configured to execute engine control while
The crankshaft sensor is configured such that the crankshaft rotation signal is discontinuous with respect to the rotation of the crankshaft at a specific rotation angle position of the crankshaft,
A specific rotation angle position of the crankshaft is detected based on a crankshaft rotation signal output from the crankshaft sensor, and the engine rotation position is specified from the change state of the crankshaft rotation signal or the camshaft rotation signal at that time. Providing a second rotational position specifying means,
Even if the first rotational position specifying means can specify the rotational position, the rotational position is determined by the second rotational position specifying means before the rotational position is specified by the first rotational position specifying means. When the engine is specified, the engine control apparatus is configured to start the engine control based on the rotational position specified by the second rotational position specifying means.   A camshaft sensor that is provided on the camshaft of the engine and generates a camshaft rotation signal that changes according to the rotational position of the camshaft;
  A crankshaft sensor that is provided on the crankshaft of the engine and generates a crankshaft rotation signal at every predetermined rotation angle of the crankshaft;
  Stop position estimating means for estimating a rotation stop position of the engine based on at least one of the camshaft rotation signal and the crankshaft rotation signal when the engine stops from the operating state;
  First rotational position specifying means for specifying a rotational position per one engine cycle based on the stop position estimated by the stop position estimating means and the camshaft rotation signal when the engine is started;
  When the engine rotation position is specified by the first rotation position specifying means, engine control based on the rotation position is started, and then the engine rotation position is updated based on the crankshaft rotation signal. An engine control device configured to execute engine control while
  Second rotation position specifying means for specifying the rotation position of the engine based on a change waveform of the cam shaft rotation signal;
  Even if the first rotational position specifying means can specify the rotational position, the rotational position is determined by the second rotational position specifying means before the rotational position is specified by the first rotational position specifying means. When the engine is specified, the engine control apparatus is configured to start the engine control based on the rotational position specified by the second rotational position specifying means. A third rotational position identifying means for identifying the rotational position of the engine based on a change waveform of the camshaft rotational signal;
When the engine rotational position is first identified by any of the first rotational position identifying means, the second rotational position identifying means, and the third rotational position identifying means at the time of starting the engine, The engine control apparatus according to claim 1, wherein engine control based on the specified rotational position is started. The stop position estimating means includes
Rotation direction determination means for determining whether the engine is rotating forward or backward from the change state of the camshaft rotation signal or the crankshaft rotation signal,
When the rotational direction of the engine is specified by the rotational direction determining means, the stop position of the engine is estimated based on the determination result of the rotational direction determining means, and when the rotational direction of the engine cannot be specified by the rotational direction determining means The engine control device according to any one of claims 1 to 3, wherein the engine stop position at the time of engine normal rotation and engine reverse rotation is estimated. The stop position estimating means includes
As the rotation direction determination means,
First determination means for determining a rotation direction of the engine from a change state of the cam shaft rotation signal;
Second determination means for determining the engine rotation direction from the change state of the crankshaft rotation signal;
When the engine rotation direction is specified by any of the first determination means and the second determination means, an engine stop position is estimated based on the specified rotation direction, and the first determination means The engine stop position at the time of engine normal rotation and engine reverse rotation is estimated when both the determination unit and the second determination unit cannot specify the rotation direction of the engine. Engine control device.   When a plurality of stop positions are estimated by the stop position estimating means, the plurality of stop positions are preset as inappropriate for specifying the rotational position of the engine by the first rotational position specifying means. It is determined whether or not the vehicle is at a stop position, and when the plurality of stop positions are inappropriate stop positions for specifying the rotational position of the engine, the stop position estimation means prohibits estimation of the stop position. The stop position estimation prohibiting means for prohibiting the first rotational position specifying means from specifying the rotational position of the engine at the next engine start is provided. Engine control device.

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