JP5379219B2 - Rotation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve accuracy in determining normal rotation or reverse rotation of a rotary shaft based on a rotation signal. <P>SOLUTION: A pulse width WIPOS of a pulse-like rotation signal POS outputted by a crank angle sensor every time when a crankshaft (rotary shaft) of an internal combustion engine rotates by a unit crank angle is set so as to differ according to the rotational direction of the crankshaft, and the pulse width WIPOS and a threshold value SL are compared to thereby discriminate between the normal rotation and reverse rotation of the crankshaft (rotary shaft). Then, in a state that an engine rotation speed is increased, a state that an updating order of a cylinder with a piston determined to be in a predetermined position is normal, a state that an engine load is increased, a state that the engine is started to operate, a state that intake pressure is increased and a state that a voltage of a battery provided in the engine is increased, the crankshaft is assumed to be normally rotating, and the threshold value SL is updated based on an average value AVWIPOS of the pulse width WIPOS in that occasion. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a rotation detection device that determines normal rotation / reverse rotation of a rotation shaft based on rotation signals that differ depending on normal rotation / reverse rotation of the rotation shaft.

  Patent Document 1 includes a signal detector that outputs a crankshaft rotation signal that is generated in synchronization with the rotation of the crankshaft of the engine and is a pulse train composed of a plurality of pulses having different pulse widths depending on the rotation direction of the crankshaft. There is disclosed an engine control device that detects a rotation direction of a crankshaft from a pulse width of a pulse train of the crankshaft rotation signal.

JP 2009-002193 A

  As described above, it is configured to output a rotation signal that varies depending on the rotation direction, and when a forward rotation / reverse rotation determination is performed by comparing the pulse width or signal level of the rotation signal with a threshold value, the rotation signal is output. There is a problem that the pulse width and signal level at the time of forward rotation and reverse rotation are varied due to circuit variations and deterioration, and the accuracy of forward / reverse rotation determination based on the threshold value is lowered.

  The present invention has been made in view of the above-described problems, and an object thereof is to improve the accuracy of forward / reverse rotation determination of a rotating shaft.

Therefore, in the present invention, the rotation of the output shaft is compared by comparing the pulse width of the rotation signal output as a pulse signal with a longer pulse width in the reverse rotation state than the normal rotation state of the output shaft of the internal combustion engine with a threshold value. In the rotation detection device for detecting a direction, the threshold value is changed according to a pulse width of the rotation signal when the output shaft is in a normal rotation state.
In the present invention, the rotation direction of the output shaft is detected based on the pulse width of the rotation signal output as a pulse signal having a longer pulse width in the reverse rotation state than in the normal rotation state of the output shaft of the internal combustion engine. In the rotation detection device, the pulse width for determining that the rotation direction of the output shaft is normal rotation is changed based on the pulse width of the rotation signal when the output shaft is in the normal rotation state. did.

  According to the above-described invention, it is possible to improve the accuracy of determining whether the rotation axis is normal or reverse based on rotation signals that differ depending on whether the rotation axis is normal or reverse.

1 is a system configuration diagram of an internal combustion engine in an embodiment. It is sectional drawing which shows the variable valve timing mechanism in embodiment. It is a figure which shows the structure of the crank angle sensor and cam sensor in embodiment. It is a time chart which shows the output characteristic of the crank angle sensor and cam sensor in an embodiment. It is a time chart which shows the difference in the pulse width by the forward rotation / reverse rotation of the rotation signal POS in the embodiment. 6 is a flowchart illustrating forward / reverse rotation determination processing in the embodiment. It is a flowchart which shows the setting process of the threshold value in embodiment.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a configuration diagram of a vehicle internal combustion engine 101 to which a rotation detection device according to the present invention is applied. In the present embodiment, the internal combustion engine 101 is an in-line four-cylinder engine.

In FIG. 1, an intake pipe 102 of an internal combustion engine 101 is provided with an electronic control throttle 104 that opens and closes a throttle valve 103b by a throttle motor 103a.
The internal combustion engine 101 sucks air into the combustion chamber 106 of each cylinder through the electronic control throttle 104 and the intake valve 105.
A fuel injection valve 131 is provided in the intake port 130 of each cylinder, and the fuel injection valve 131 is opened by an injection pulse signal from an engine control unit (hereinafter referred to as ECU) 114 to inject fuel.

The fuel in the combustion chamber 106 is ignited and burned by spark ignition by a spark plug (not shown).
The combustion gas in the combustion chamber 106 flows out to the exhaust pipe 111 through the exhaust valve 107. The front catalytic converter 108 and the rear catalytic converter 109 provided in the exhaust pipe 111 purify the exhaust gas flowing through the exhaust pipe 111 and release the purified exhaust gas into the atmosphere.

The intake camshaft 134 and the exhaust camshaft 110 are integrally provided with a cam, and the intake valve 105 and the exhaust valve 107 are operated by this cam.
The variable valve timing mechanism 113 provided on the intake camshaft 134 continuously changes the valve timing of the intake valve 105 by continuously changing the rotation phase of the intake camshaft 134 relative to the crankshaft 120 (output shaft, rotation shaft). It is a mechanism to change to.

FIG. 2 shows the structure of the variable valve timing mechanism 113.
The variable valve timing mechanism 113 is fixed to a sprocket 25 that rotates in synchronization with the rotation of the crankshaft 120, and is attached to one end of the intake camshaft 134 by a first rotating body 21 that rotates integrally with the sprocket 25 and a bolt 22a. A second rotating body 22 that is fixed and rotates integrally with the intake camshaft 134, and a cylindrical intermediate that meshes with the inner peripheral surface of the first rotating body 21 and the outer peripheral surface of the second rotating body 22 by the helical spline 26. And a gear 23.

A drum 27 is connected to the intermediate gear 23 via a multi-thread screw 28 such as a triple thread, and a torsion spring 29 is interposed between the drum 27 and the intermediate gear 23.
The intermediate gear 23 is urged in the retarding direction (left direction in FIG. 2) by a torsion spring 29. When the electromagnetic retarder 24 generates a magnetic force, the intermediate gear 23 passes through the drum 27 and the multi-thread screw 28. It moves in the advance direction (right direction in FIG. 2).
In accordance with the position of the intermediate gear 23 in the axial direction, the relative phase of the rotating bodies 21 and 22 changes, and the phase of the intake camshaft 134 with respect to the crankshaft 120 changes.

The ECU 114 controls the electromagnetic retarder 24 according to the operating state of the internal combustion engine 101.
The variable valve timing mechanism 113 is not limited to the structure shown in FIG. 2, and a known mechanism that changes the rotational phase of the camshaft relative to the crankshaft can be appropriately employed. For example, a variable valve timing mechanism provided with a spiral guide disclosed in JP2003-184516A, a hydraulic vane type variable valve timing mechanism disclosed in JP2007-120406A, etc. The valve timing of the intake valve 105 can be changed.

The internal combustion engine 101 includes an alternator 171 (generator). The rotation driving force of the crankshaft 120 is transmitted to the alternator 171 by the transmission mechanism 172, whereby the alternator 171 rotates at a speed proportional to the rotation of the internal combustion engine 101, and the power generation is possible.
A positive terminal of the battery 173 is connected to the output terminal of the alternator 171 and an electric load 174 is connected. The battery 173 is charged by the alternator 171 and the generated current of the alternator 171 is supplied to the fuel injection valve 131 or the like. It is supplied to an electric load 174 that is constantly driven such as an ignition coil (not shown), and further supplied to an electric load 174 such as a headlamp, a wiper, and an air conditioner as necessary.

The ECU 114 incorporates a microcomputer, performs calculations according to a program stored in advance in a memory, and controls the electronic control throttle 104, the variable valve timing mechanism 113, the fuel injection valve 131, and the like.
The ECU 114 receives detection signals from various sensors. As various sensors, an internal combustion engine 101 is provided on an accelerator pedal 116a, and an accelerator opening sensor 116 that detects an accelerator opening ACC, an airflow sensor 115 that detects an intake air amount Q of the internal combustion engine 101, and a rotation of a crankshaft 120. In response to the crank angle sensor (rotation sensor) 117 that outputs a pulsed rotation signal (unit crank angle signal) POS, the throttle sensor 118 that detects the opening TVO of the throttle valve 103b, and the temperature TW of the cooling water of the internal combustion engine 101 A water temperature sensor 119 for detecting the pressure, a cam sensor 133 for outputting a pulsed cam signal PHASE according to the rotation of the intake camshaft 134, a brake switch 122 that is turned on when the brake pedal 121 is depressed, and a vehicle traveling speed VSP. Vehicle speed sensor 123 to detect, suction And a like intake pressure sensor 126 for detecting a pressure PB.
Further, the ECU 114 receives an on / off signal of an ignition switch 124 that is a main switch for operating / stopping the internal combustion engine 101, an on / off signal of a starter switch 125, and a voltage signal VB of the battery 173.

FIG. 3 shows the structure of the crank angle sensor 117 and the cam sensor 133.
The crank angle sensor 117 is pivotally supported by the crankshaft 120 and has a signal plate 152 provided with a protrusion 151 as a detected portion around the crankshaft 120, and is fixed to the internal combustion engine 101 side. The crank angle sensor 117 detects the protrusion 151 and outputs a rotation signal POS. And a rotation detecting device 153 for outputting.

The rotation detection device 153 includes various processing circuits including a waveform generation circuit, a selection circuit, and the like together with a pickup that detects the protrusion 151, and the rotation signal POS output from the rotation detection device 153 is normally at a low level. When the protrusion 151 is detected, it changes to a high level for a predetermined time.
The protrusions 151 of the signal plate 152 are provided at equal intervals with a crank angle of 10 deg, but the portions where the two protrusions 151 are continuously removed are opposed across the rotation center of the crankshaft 120. There are two places.
The number of protrusions 151 may be one, or three or more may be continuously deleted.

Therefore, the pulse-like rotation signal POS output from the crank angle sensor 117 (rotation detection device 153) is continuously set to the high level 16 times every 10 degrees (unit crank angle) as shown in FIG. After the change, the low level is maintained for 30 deg, and the high level is continuously changed again 16 times.
The first rotation signal POS after the low level period of 30 deg is output at intervals of 180 deg crank angle, and the crank angle 180 deg is the stroke phase difference between the cylinders in the four-cylinder engine 101 of this embodiment, In other words, it corresponds to the ignition interval.

On the other hand, the cam sensor 133 is pivotally supported at the end of the intake camshaft 134 and is fixed to the internal combustion engine 101 side with a signal plate 158 provided with a protruding portion 157 as a detected portion around it, and detects the protruding portion 157. And a rotation detecting device 159 that outputs a cam signal PHASE.
The rotation detection device 159 includes various processing circuits including a waveform shaping circuit and the like together with a pickup that detects the protrusion 157.

The projections 157 of the signal plate 158 are provided at one, three, four, and two projections at four positions every 90 degrees in cam angle, and in the portion where a plurality of projections 157 are continuously provided, the projections 157 Are set at 30 deg in crank angle and 15 deg in cam angle.
The cam signal PHASE, which is a pulse signal output from the cam sensor 133 (rotation detection device 159), is normally at a low level as shown in FIG. 4, and is at a high level for a certain time by detecting the protrusion 157. Every time the cam angle is 90 deg and the crank angle is 180 deg, it changes to a high level, one by one, three in succession, four in succession, and two in succession.

The single cam signal PHASE and the head signals of a plurality of cam signals PHASE that are continuously output are output at 180 deg intervals in terms of crank angle.
The continuous output number of the cam signal PHASE indicates a cylinder number, and in the four-cylinder engine 101 of the present embodiment, the phase difference of the stroke between the cylinders is 180 deg in crank angle, and ignition is performed from the first cylinder → the third cylinder → the second cylinder. This corresponds to the order of 4 cylinders to 2nd cylinders.

The ECU 114 counts the number of continuous outputs of the cam signal PHASE, thereby discriminating the cylinder where the piston position is the default position such as the top dead center TDC, and performing fuel injection and ignition based on the result of such discrimination. The cylinder to be activated is specified, and an injection pulse signal and an ignition signal are output.
For example, the tooth missing position of the rotation signal POS is determined from the periodic change of the rotation signal POS, etc., and the interval of the crank angle of 180 deg for counting the number of occurrences of the cam signal PHASE is specified based on this tooth missing position. Next, the cylinder which becomes the top dead center is detected based on the number of occurrences of the cam signal PHASE.

Here, the phase of the rotation signal POS and the cam signal PHASE changes when the rotation phase of the intake camshaft 134 with respect to the crankshaft 120 is changed by the variable valve timing mechanism 113.
Therefore, the ECU 114 detects the reference crank angle position REF on the basis of the missing portion of the rotation signal POS, and the angle from the reference crank angle position REF to the output of the cam signal PHASE is determined by the variable valve timing mechanism 113. It is detected as a value indicating the rotational phase of the intake camshaft 134.

In the control of the variable valve timing mechanism 113, the ECU 114 calculates the target rotational phase based on the engine operating state such as the engine load and the engine rotational speed, and based on the deviation between the actual rotational phase and the target rotational phase. An operation amount of the electromagnetic retarder 24 is calculated by a proportional / integral / differential operation, and feedback control for driving the electromagnetic retarder 24 is performed based on the operation amount.
As described above, the rotation signal POS is used to detect the rotation phase of the intake camshaft 134, to calculate the engine rotation speed NE, and to detect the rotation position of the crankshaft 120.

That is, the rotation signal POS also serves as a measurement signal of the rotation position of the crankshaft 120, and counts the number of occurrences of the rotation signal POS from the reference crank angle position REF detected with reference to the missing portion or missing portion of the rotation signal POS. Thus, the rotational position of the crankshaft 120 can be detected.
However, immediately before the internal combustion engine 101 stops, the internal combustion engine 101 (crankshaft 120) may rotate in the reverse direction due to in-cylinder compression pressure or the like, and the rotation signal POS during reverse rotation is the same as during normal rotation. If the number of occurrences is counted, an error occurs in the detection of the stop position of the crankshaft 120.

Therefore, the crank angle sensor 117 (rotation detection device 153) has a pulse width between forward rotation and reverse rotation of the crankshaft 120, which is the output shaft of the internal combustion engine 101, so that the forward rotation / reverse rotation of the internal combustion engine 101 can be determined. Rotation signals POS (pulse signals) having different values are output (see FIG. 5).
As a method for generating pulse signals having different pulse widths depending on the rotation direction of the rotating shaft, for example, a method disclosed in Japanese Patent Application Laid-Open No. 2001-165951 is used. Specifically, as detection pulse signals of the protrusions 151 of the signal plate 152, two signals whose phases are shifted from each other are generated, and these signals are compared to determine normal rotation / reverse rotation, and different pulse widths. One of the two pulse signals generated as WIPOS is selected and output based on the forward / reverse determination result.

The ECU 114 measures the pulse width WIPOS of the rotation signal POS, and compares the measured value WIPOS of the pulse width with the threshold SL, which is a threshold value for forward / reverse rotation, to determine whether the pulse width WIPOS during forward rotation is satisfied. Then, it is determined whether the pulse width WIPOS at the time of reverse rotation is obtained, and it is determined whether the crankshaft 120 that is the output shaft of the internal combustion engine 101 is rotating forward or reversely.
In this embodiment, as shown in FIG. 5, the pulse width WIPOS during forward rotation is set to 45 μs and the pulse width WIPOS during reverse rotation is set to 90 μs, but the pulse width WIPOS is set to 45 μs and 90 μs as described above. It is not limited. Alternatively, the pulse width WIPOS may be set to be larger during forward rotation than during reverse rotation.

Further, in the example shown in FIG. 5, the rotation signal POS is a pulse signal that changes to a high level for a certain time when the rotation signal POS reaches a predetermined angular position at a normal low level. In this case, the low level period is set to be different in the rotation direction, and the length of the low level period is measured as the pulse width WIPOS. Thus, the rotational direction can be determined.
The threshold value SL used for forward / reverse rotation discrimination is set to an intermediate value between the forward pulse width WIPOS and the reverse pulse width WIPOS. For example, if the measured pulse width WIPOS is equal to or greater than the threshold value SL, If the measured pulse width WIPOS is less than the threshold value SL, it is determined that it is in the forward rotation state.

When the crankshaft 120 is rotating forward, it is determined that the crankshaft 120 has rotated in the forward rotation direction at the time when the rotation signal POS is output by the crank angle corresponding to the generation interval of the rotation signal POS than before. . If the crankshaft 120 is in reverse rotation, it is determined that the crankshaft has rotated in the reverse rotation direction at the output time of the rotation signal POS by the crank angle corresponding to the generation interval of the rotation signal POS than the previous time (stop position detecting means). .
As described above, if the stop position of the crankshaft 120 is detected by discriminating between normal rotation and reverse rotation, even if the crankshaft 120 is reversely rotated immediately before the internal combustion engine 101 is stopped, the stop position of the crankshaft 120 is In other words, the piston position of each cylinder at the time of stopping can be accurately determined, and fuel injection / ignition can be started early at the time of restart.

For example, when the crankshaft 120 reverses immediately before the internal combustion engine 101 stops and the stop position of the crankshaft 120 becomes unknown, at the time of restart, for example, the rotation position of the crankshaft 120 waits for detection of a missing portion of the rotation signal POS. It is necessary to restart the detection of fuel, and the start of fuel injection / ignition is delayed.
In the present embodiment, the ECU 114 automatically stops the internal combustion engine 101 when the automatic stop condition is satisfied while the internal combustion engine 101 is idling, and when the restart condition is satisfied after the internal combustion engine 101 is automatically stopped, The engine has an idle stop control function for automatically restarting the engine. If the internal combustion engine 101 is automatically restarted, if the fuel injection / ignition can be started early, the restartability of the internal combustion engine 101 can be improved. Can be improved.

In the idle stop control, for example, the vehicle speed VSP is 0 km / h, the engine rotational speed NE is equal to or lower than a predetermined rotational speed, the accelerator opening ACC is fully closed, the brake switch 122 is ON (braking state), and the cooling water temperature TW is a predetermined temperature. When all the above conditions are satisfied, it is determined that the idle stop condition (automatic stop condition) is satisfied, the fuel injection / ignition is stopped, and the internal combustion engine 101 is stopped.
The predetermined rotation speed is a value for determining the idle rotation state, and is set slightly higher than the target idle rotation speed. The predetermined temperature is a state in which the engine 101 is completely warmed (state after warm-up). It is a value for judging.

On the other hand, when the internal combustion engine 101 is automatically stopped, for example, the brake switch 122 is switched to OFF (non-braking state), the accelerator pedal is depressed, or the duration time of the automatic stop state becomes longer than the reference time. If it is determined that the battery voltage has decreased, it is determined that the restart condition is satisfied, and the fuel injection / ignition for the internal combustion engine 101 is resumed.
At the time of restart, the internal combustion engine 101 can be started to rotate using the starter motor, and the internal combustion engine 101 can be started to rotate by the combustion of fuel in the combustion chamber.

By the way, as described above, the forward rotation / reverse rotation determination of the crankshaft 120 is performed by comparing the pulse width WIPOS of the rotation signal POS and the threshold SL. The pulse width WIPOS of the rotation signal POS is determined based on the crank angle. It fluctuates due to variations in the sensor 117 (rotation detection device 153) and variations in the ECU 114 that measures the pulse width WIPOS.
For this reason, when the threshold value SL is given as a fixed value in advance, there is a possibility that the normal rotation / reverse rotation of the crankshaft 120 cannot be correctly determined.

Therefore, the ECU 114 has a learning function of the threshold value SL that sets and stores the threshold value SL based on the measurement result of the actual pulse width WIPOS, and performs forward / reverse rotation determination based on the stored threshold value SL. .
Below, the learning function of threshold value SL by ECU114 is demonstrated according to the flowchart of FIG.6 and FIG.7.

The flowchart of FIG. 6 shows a routine that is executed each time the rotation signal POS is generated in the ECU 114.
In step S1001, the pulse width WIPOS of the rotation signal POS is measured.
Specifically, for example, the rise and fall of the rotation signal POS is detected, the time from the rise to the fall is measured, and the measured time is set as the pulse width WIPOS.

In the next step S1002, the pulse width WIPOS measured in step S1001 is compared with the threshold value SL. If the pulse width WIPOS is less than the threshold value SL, it is determined that the crankshaft 120 is rotating forward, the process proceeds to step S1003, and a flag fHANTEN is set to zero.
On the other hand, if it is determined in step S1002 that the pulse width WIPOS is greater than or equal to the threshold value SL, it is determined that the crankshaft 120 is rotating in reverse, and the process proceeds to step S1004 where 1 is set in the flag fHANTEN.

That is, the state where the flag fHANTEN is set to 1 indicates the reverse rotation state of the crankshaft 120, and the state where the flag fHANTEN is set to zero indicates the normal rotation state of the crankshaft 120.
Therefore, the functions of steps S1001 to S1004 correspond to forward / reverse rotation determining means.

In step S1005, interrupt processing other than forward / reverse rotation determination performed every time the rotation signal POS is generated is executed.
The interrupt processing includes detection of the rotational position of the crankshaft 120 by counting up the rotation signal POS, detection of a missing portion of the rotation signal POS, and the like.

On the other hand, the flowchart of FIG. 7 shows a routine that is executed by the ECU 114 at every predetermined time (for example, 10 ms).
In step S2001, information indicating the operating state of the internal combustion engine 101 such as the engine speed NE, the on / off signal of the starter switch 125, and the intake air amount Q detected by the airflow sensor 115 is read.

In the next step S2002 (rotation condition determining means), it is determined from the information (engine operating condition) read in step S2001 whether or not the condition is that the crankshaft 120 rotates forward.
Specifically, when at least one of the following conditions (1) to (6) is satisfied, the crankshaft 120 is determined to be a condition for normal rotation.
In addition, if the normal rotation is determined based on the fact that a plurality of the following conditions (1) to (6) are satisfied, it is possible to improve the accuracy of forward / reverse determination.

(1) The engine rotational speed NE is equal to or higher than the predetermined rotational speed NES (2) The cylinder determined by the cam signal PHASE is switched along the normal rotation direction (3) The engine load TP is equal to or higher than the predetermined load TPS (4) Starter ON state of switch 125 (5) State in which intake pressure PB has increased or decreased from atmospheric pressure to a predetermined level or higher (6) Battery voltage VB is equal to or higher than predetermined voltage VBS

The condition (1) is to determine whether or not the engine rotational speed NE, in other words, the rotational speed of the crankshaft 120 is increased. The predetermined rotational speed NES is set to a rotational speed that does not reach when the crankshaft 120 is reversely rotated. For example, the predetermined rotational speed NES is set to 500 rpm.
That is, the maximum value of the engine rotational speed NE at the time of reverse rotation of the internal combustion engine 101 is lower than the maximum value of the engine rotational speed NE at the time of forward rotation of the internal combustion engine 101. When the engine rotational speed NE that has exceeded is reached, it can be determined that the crankshaft 120 (internal combustion engine 101) is rotating forward.

The condition (2) is to determine whether or not the cylinder with the piston in the predetermined position, which is determined by the ECU 114 based on the cam signal PHASE, is updated in the order corresponding to the normal rotation of the internal combustion engine 101. As described above, since the ignition order of the internal combustion engine 101 is the first cylinder → the third cylinder → the fourth cylinder → the second cylinder, this ignition order is an update order corresponding to the forward rotation of the internal combustion engine 101, If the cylinder determined to be the predetermined piston position is updated in this order, the internal combustion engine 101 (crankshaft 120) is rotating forward.
In other words, the normal rotation / reverse rotation of the internal combustion engine 101 (crankshaft 120) is determined by determining whether the input pattern of the rotation signal POS and the cam signal PHASE to the ECU 114 is a normal pattern.

The condition (3) is for determining whether or not the engine 101 is operated with an engine load that can be realized only in the normal rotation state of the internal combustion engine 101. Therefore, the predetermined load TPS is set to an engine load higher than a low load state in which the engine rotation is reversed from the normal rotation just before the stop of the internal combustion engine 101 to the reverse rotation, and the internal combustion engine 101 is operated with the engine load TP equal to or higher than the predetermined load TPS. If so, it is determined to be in the forward rotation state.
In other words, when the internal combustion engine 101 is rotating in reverse, the internal combustion engine 101 is not operated with an engine load exceeding the predetermined load TPS, and if the engine load is equal to or greater than the predetermined load TPS, the internal combustion engine 101 ( It is determined that the crankshaft 120) is rotating forward.

The state quantity representing the engine load indicates the amount of air sucked into the internal combustion engine 101, such as the intake air quantity Q detected by the air flow sensor 115 and the fuel injection quantity calculated based on the intake air quantity Q. It is preferable to use state quantities.
Here, the higher the predetermined load TPS is set, the higher the determination accuracy of the forward rotation state. However, for example, the predetermined load TPS is set to such an extent that the condition (4) is determined during the idling operation of the internal combustion engine 101. Even so, necessary and sufficient determination accuracy can be obtained.

  The condition (4) is for determining whether or not the internal combustion engine 101 is in a starting operation state. When the starter switch 125 is on and the cranking state is such that the internal combustion engine 101 is rotated by the starter motor, the crankshaft 120 rotates in the rotation direction of the starter motor, that is, in the forward rotation direction. Therefore, if the starter switch 125 is in an on state, in other words, if the internal combustion engine 101 is in a starting operation state, it can be determined that the crankshaft 120 is rotating forward.

Condition (5) is to determine whether or not the intake pressure PB, which is the pressure in the intake pipe 102, has developed, in other words, whether or not the intake pressure PB has changed from atmospheric pressure to a predetermined level or more.
The reverse rotation of the crankshaft 120 occurs immediately before the internal combustion engine 101 is stopped. In this case, the intake pressure PB is near atmospheric pressure. In other words, when the intake pressure PB changes from atmospheric pressure to a predetermined level or more, it can be determined that the internal combustion engine 101 (crankshaft 120) is in a normal rotation state, and the intake pressure PB increases from the atmospheric pressure to a predetermined level or more. It can be determined by comparing the intake pressure PB with a predetermined pressure PBS.

As described above, since the intake pressure PB is in the vicinity of the atmospheric pressure during the reverse rotation, the intake pressure PB that is a predetermined distance or more away from the atmospheric pressure and does not reach the reverse rotation of the crankshaft 120 is used as the predetermined pressure PBS. When it is set and it is farther from the atmospheric pressure than the predetermined pressure PBS, it can be determined that it is in the forward rotation state.
Here, if the internal combustion engine 101 is a naturally aspirated engine, the intake pressure PB is close to the atmospheric pressure in the fully opened operation state, so the predetermined pressure PBS is set to a negative pressure, and the intake pressure PB is a negative pressure greater than the predetermined pressure PBS. In other words, in other words, when the internal combustion engine 101 is operated at a low load with a large intake negative pressure, the normal rotation of the internal combustion engine 101 (crankshaft 120) is determined.

  Further, when the internal combustion engine 101 includes a supercharger, the intake pressure PB becomes higher than the atmospheric pressure due to supercharging, so the predetermined pressure PBS is set to a positive pressure, and the intake pressure PB is larger than the predetermined pressure PBS. It is possible to determine the normal rotation of the internal combustion engine 101 (crankshaft 120) when the engine load is at a positive pressure.

Condition (6) is based on the battery voltage VB to determine that the alternator 171 driven by the internal combustion engine 101 is generating power.
The alternator 171 generates electric power when the internal combustion engine 101 rotates forward, and the battery voltage VB is increased by the electric power generated by the alternator 171. Therefore, the battery voltage VB reached when the alternator 171 generates electric power is set to a predetermined voltage VBS.

Thus, if the battery voltage VB is equal to or higher than the predetermined voltage VBS, it can be determined that the alternator 171 is generating power. If the alternator 171 is generating power, the internal combustion engine 101 (crankshaft 120) rotates forward. Can be judged.
When the internal combustion engine 101 is a naturally aspirated engine, the intake pressure PB approaches the atmospheric pressure from the negative pressure due to an increase in the engine load. As described above, the intake pressure PB is the atmospheric pressure even in the reverse state. Therefore, when the engine load is determined based on the intake pressure PB, the vicinity of the atmospheric pressure is excluded from the normal rotation determination region, and the internal combustion engine 101 rotates forward when the negative pressure is generated. Can be determined.

On the other hand, in the case of the internal combustion engine 101 provided with the supercharger, the intake pressure PB becomes a higher positive pressure from the atmospheric pressure due to an increase in the engine load. When the intake pressure PB is higher than the atmospheric pressure by a predetermined level or more, it can be determined that the internal combustion engine 101 is rotating forward.
If it is determined in step S2002 that the engine speed NE, the engine load TP, and the like are not conditions for normal rotation of the internal combustion engine 101 (crankshaft 120), in other words, the internal combustion engine 101 (crankshaft 120) is reversely rotated. If there is a possibility, the process proceeds to step S2003.

In step S2003, the counter CNTNE for counting the number of samples of the pulse width WIPOS is reset to zero, and the average value AVWIPOS of the pulse width WIPOS is reset to the initial value.
As the initial value, a design value (design value = 45 μs) of the pulse width WIPOS during forward rotation is used.

On the other hand, if it is determined in step S2002 that the engine speed NE, the engine load TP, and the like are conditions for normal rotation of the internal combustion engine 101 (crankshaft 120), in other words, the internal combustion engine 101 (crankshaft 120). When it is estimated that is rotating forward, the process proceeds to step S2004.
In step S2004, the counter CNTNE is increased by 1 from the previous value CNTNEz.

  In the next step S2005, the recently measured pulse width WIPOS and the previous average value AVWIPOSz are weighted and averaged, and this weighted average value is used as the current average value AVWIPOS.

AVWIPOS = AVWIPOSz × 0.9 + WIPOS × 0.1
The smoothing process (moving average process) of the pulse width WIPOS is not limited to the above-described weighted average calculation, and may be a simple average calculation or the like. Further, the coefficients used for the weighted average calculation are not limited to the values shown in the above formula.

In step S2006, it is determined whether the counter CNTNE is equal to or greater than a determination value.
The determination value is 100, for example, and is set based on the number of samples sufficient to obtain the average value of the pulse width WIPOS of the rotation signal POS during forward rotation.

If it is determined in step S2006 that the counter CNTNE is less than the determination value, it is determined that the reliability of the average value AVWIPOS is insufficient, and the flow proceeds to step S2010 bypassing steps S2007 to S2009.
In step S2010, the value of the counter CNTNE increased in the current step S2004 is set to the previous value CNTNEz, and the average value AVWIPOS updated in the current step S2005 is set to the previous value AVWIPOSz.

On the other hand, if it is determined in step S2006 that the counter CNTNE is greater than or equal to the determination value, the process proceeds to step S2007.
In step S2007, the previously stored margin MA is added to the average value AVWIPOS updated in step S2005 this time, and the addition result is set as a threshold SL used for forward / reverse rotation determination in step S1002. A new threshold value SL is stored.

Threshold SL = AVWIPOS + margin MA
In the present embodiment in which the pulse width WIPOS at the time of forward rotation is set to 45 μs and the pulse width WIPOS at the time of reverse rotation is set to 90 μs, the margin MA is set to about 10 μs, for example.

That is, when the pulse width WIPOS is equal to or longer than the time obtained by adding the margin MA to the average pulse width AVIPPOS during forward rotation, the reverse rotation of the internal combustion engine 101 (crankshaft 120) is determined.
The margin MA is preliminarily stored in consideration of the difference between the standard pulse width WIPOS during forward rotation and the standard pulse width WIPOS during reverse rotation, the variation width of the pulse width WIPOS, and the like. However, depending on whether the pulse width WIPOS at the time of forward rotation is shorter or longer than the standard value, a different value is set as the margin MA, or at the time of reverse rotation based on the threshold SL set based on the margin MA. The margin MA can be corrected based on the pulse width WIPOS determined as the pulse width.

If the pulse width WIPOS during forward rotation is longer than the pulse width WIPOS during reverse rotation, the result obtained by subtracting the margin MA from the average value AVWIPOS may be used as the threshold value SL.
The processing in steps S2004 to S2007 corresponds to a function as a threshold setting unit.
As described above, if the threshold SL used for forward / reverse rotation determination is learned based on the pulse width WIPOS measured while the internal combustion engine 101 (crankshaft 120) is normally rotating, When the pulse width WIPOS at the time of reverse rotation varies with respect to the design value due to various factors, the threshold SL can be changed in response to this, so that the accuracy of forward / reverse rotation determination can be improved. it can.

Then, if the forward / reverse determination accuracy is improved, the determination accuracy of the stop position of the internal combustion engine 101 is improved, and fuel injection / ignition at the time of restart from the idle stop state can be controlled quickly and with high accuracy, The restartability of the internal combustion engine 101 can be improved.
In step S2008 (diagnostic means), it is determined whether the threshold value SL updated in step S2007 is greater than or equal to the maximum value or less than the minimum value.

In the present embodiment in which the pulse width WIPOS during forward rotation is set to 45 μs and the pulse width WIPOS during reverse rotation is set to 90 μs, the maximum value is set to 150 μs, for example, and the minimum value is set to 20 μs, for example. .
The maximum value / minimum value is set based on the variation range of the pulse width WIPOS, and is set to a value that does not exceed the threshold SL in the allowable variation of the pulse width WIPOS.

In other words, the threshold SL varies within a range between the maximum value and the minimum value with respect to the variation in the allowable pulse width WIPOS, and the pulse width WIPOS is caused by an abnormality of the crank angle sensor 117 (rotation detection device 153). Is changed to exceed a permissible variation, the threshold value SL is set to a value outside the range between the maximum value and the minimum value.
Therefore, if it is determined in step S2008 that the threshold value SL is greater than or equal to the maximum value or less than the minimum value, the pulse width WIPOS of the rotation signal POS is set due to an abnormality in the crank angle sensor 117 (rotation detection device 153). It can be estimated that it has changed beyond the allowable variation.

If an abnormality occurs in the pulse width WIPOS of the rotation signal POS, the forward / reverse determination based on the determination of the pulse width WIPOS becomes impossible, thereby reducing the restartability of the internal combustion engine 101. Step S2009 Proceed to, and idle stop control is prohibited.
That is, if forward / reverse rotation determination based on the pulse width WIPOS of the rotation signal POS becomes impossible, when the internal combustion engine 101 reverses immediately before stopping, the stop position of the internal combustion engine 101 is not correctly detected. It becomes impossible to set the fuel injection timing and ignition timing at the time of restart.

For this reason, at the time of restart, the fuel injection / ignition cannot be started until the missing position of the rotation signal POS is detected and the cylinder of the predetermined piston position is determined. Startability is reduced.
Therefore, in step S2009 (invalid means), the idle stop control is prohibited to prevent the idle stop from being executed in a state where the restartability is lowered, and then the process proceeds to step S2010.

However, at the time of restart, even if fuel injection / ignition is started after the missing position of the rotation signal POS is detected and the cylinder of the predetermined piston position is determined, the start to the extent that the start acceleration performance is impaired If there is no degradation in performance or if it is allowed to degrade in startability, detection of the stop position based on forward / reverse rotation is prohibited, or the detection result of the stop position is invalidated and idle stop is performed. Implementation of the control can be allowed.
On the other hand, if it is determined in step S2008 that the threshold value SL is less than the maximum value and greater than the minimum value, it can be estimated that the pulse width WIPOS of the rotation signal POS varies within an allowable range. .

Therefore, if it is determined in step S2008 that the threshold value SL is less than the maximum value and greater than the minimum value, the process bypasses step S2009 and proceeds to step S2010, so that idle stop control, in other words, Permits detection of stop position based on forward / reverse rotation judgment.
In the embodiment shown in the flowchart of FIG. 7, it is determined that the pulse width WIPOS measured when the condition for normal rotation of the internal combustion engine 101 (crankshaft 120) is satisfied is the pulse width during normal rotation. Although the threshold value SL is learned from the pulse width WIPOS, the threshold value SL can be learned based on the pulse width WIPOS measured under the condition that the internal combustion engine 101 (crankshaft 120) is reversed.

When the threshold value SL is learned based on the pulse width WIPOS at the time of reverse rotation, it is determined whether or not the reverse rotation condition is satisfied at step S2002 in the flowchart of FIG. 7, and “AVWIPOS−margin MA” is newly set at step S2007. The threshold value SL may be set.
In the determination of the reverse rotation condition in step S2002, as disclosed in Japanese Patent Application Laid-Open No. 2004-052698, whether or not the internal combustion engine 101 (crankshaft 120) is reverse based on the cycle or cycle ratio of the rotation signal POS. Can be determined.

Specifically, when switching from normal rotation to reverse rotation immediately before the stop of the internal combustion engine 101, the cycle TPOS of the rotation signal POS becomes longer and becomes a cycle TPOS that does not occur during normal rotation, so the cycle TPOS is greater than the determination value TSL. When it becomes long, it can be judged that it is the reverse rotation conditions of the internal combustion engine 101 (crankshaft 120). The determination value TSL is set to a value that does not exceed the period TPOS when the internal combustion engine 101 stops in the normal rotation state.
Further, when the internal combustion engine 101 is switched from the normal rotation state to the reverse rotation state, the cycle TPOS suddenly becomes longer, and a cycle ratio RT (RT = TPOS) which is a ratio between the latest value TPOS of the measurement result of the cycle TPOS and the previous value TPSOz. / TPSOz) becomes so large that it does not occur during forward rotation, so that it can be determined that the reverse rotation condition of the internal combustion engine 101 (crankshaft 120) is satisfied when the cycle ratio RT is larger than the determination value RTS. The determination value RTS is set to a value that does not exceed the cycle ratio RT when the internal combustion engine 101 stops in the normal rotation state.

In the present embodiment, since the tooth missing portion where the period TPOS of the rotation signal POS is longer than the original 10 deg period is provided, as described above, when the reverse rotation condition is determined from the period TPOS, It is determined whether or not the period TPOS is a result of measuring the missing part, and when the period TPOS of the missing part is used, the determination values TSL and RTS may be switched to values adapted to the missing part. .
When it is determined that the reverse rotation condition is satisfied, an average value AVWIPOS of the pulse width WIPOS is obtained, and the threshold value SL is updated based on the average value AVWIPOS.

In the present embodiment, the pulse width WIPOS at the time of forward rotation is set to 45 μs, the pulse width WIPOS at the time of reverse rotation is set to 90 μs, and the pulse width WIPOS at the time of reverse rotation is longer, so the average value AVWIPOS of the pulse width WIPOS measured at the time of reverse rotation A value obtained by subtracting the margin MA is set as the threshold value SL. The margin MA is about 10 μs as in the forward rotation.
Further, since the period during which the internal combustion engine 101 (crankshaft 120) continuously reverses is short, the required number of samples for obtaining the average value AVWIPOS of the pulse width WIPOS may be reduced as compared with the normal rotation.

Also, when the threshold SL based on the average value AVWIPOS of the pulse width WIPOS or the average value AVWIPOS and the margin MA is calculated both when the forward rotation condition is satisfied and when the reverse rotation condition is satisfied, As a threshold SL used for forward / reverse rotation determination, an average value AVWIPOS or threshold SL obtained when the forward rotation condition is satisfied and an average value AVWIPOS or threshold SL obtained when the reverse rotation condition is satisfied may be set as an intermediate value. it can.
Here, the intermediate value can be a median value of a region sandwiched between the value at the time of forward rotation and the value at the time of reverse rotation.

Further, according to the difference in reliability depending on the number of samples of the pulse width WIPOS when the average value AVWIPOS is obtained, the learning opportunity (learning frequency), etc., the value at the time of forward rotation and the value at the time of reverse rotation are weighted. The final threshold SL can be set.
In the internal combustion engine 101 (crankshaft 120), it is possible to obtain the average value AVWIPOS by securing a larger number of samples of the pulse width WIPOS during forward rotation, and for operating in the forward rotation state. Therefore, the reliability of the average value AVWIPOS is generally higher during normal rotation.

Therefore, for example, an area sandwiched between the average value AVWIPOS obtained during forward rotation or the threshold value SL set based on the average value AVWIPOS and the average value AVWIPOS obtained during reverse rotation or the threshold value SL set based on the average value AVWIPOS. A value closer to the forward rotation value by a predetermined ratio of the region width than the median value can be set as the final threshold value SL.
In addition, the weighted average value of the average value AVWIPOS obtained at the time of forward rotation or the threshold value SL set based on the average value AVWIPOS and the average value AVWIPOS obtained at the time of reverse rotation or the threshold value SL set based on the average value AVWIPOS is finalized. It is possible to set the weight for the value obtained during normal rotation in the weighted average calculation to be larger than the weight for the value obtained during reverse rotation.

Furthermore, the learning frequency at the time of reverse rotation is lower than the learning frequency at the time of normal rotation, and the longer the elapsed time since learning, the less reliable the learning result. As the elapsed time from the time when the value AVWIPOS is obtained becomes longer, the weight for the value obtained during the reverse rotation can be made smaller, and the weight for the value obtained during the forward rotation can be made relatively larger.
In the above-described embodiment, the rotation signal POS having a different pulse width WIPOS is generated by the forward rotation and the reverse rotation as the rotation signal POS different by the forward rotation and the reverse rotation of the crankshaft 120 (the rotation shaft / output shaft). For example, it can be configured such that the amplitude (signal level) of the pulsed rotation signal POS differs between forward rotation and reverse rotation.

For example, when the rotation signal POS is a pulse signal that changes to a high level for a predetermined time when the rotation signal POS is at a normal low level and reaches a predetermined angular position, the high level height is different between forward rotation and reverse rotation. Can be configured.
Also in this case, the amplitude (signal level) corresponds to the normal rotation or the reverse rotation based on the amplitude (signal level) of the rotation signal POS when the internal combustion engine 101 is in the forward rotation condition and / or the reverse rotation condition. By setting the threshold value SL for determining whether or not to perform, the same operation and effect as in the above-described embodiment can be achieved.

Further, both the pulse width WIPOS and the amplitude of the rotation signal POS are configured to be different between normal rotation and reverse rotation. For example, the forward / reverse determination result based on the pulse width WIPOS and the normal rotation / reverse rotation based on the amplitude When the determination result matches, the forward / reverse determination result can be output, and when both the determination results do not match, the determination result that the rotation direction is unknown can be output.
In the above embodiment, the rotation signal POS that is different between forward rotation and reverse rotation is also used as the measurement signal of the rotational position of the crankshaft 120. However, the rotation signal POS for detecting forward rotation / reverse rotation of the crankshaft 120 The measurement signal of the rotational position (angle) of the crankshaft 120 can be generated individually.

However, the number of rotation detectors can be reduced and the signal processing circuit can be simplified if different rotation signals for forward and reverse rotation of the crankshaft 120 also serve as measurement signals for the rotational position of the crankshaft 120. can do.
Further, in the above embodiment, the abnormality of the crank angle sensor 117 (rotation detection device 153) is determined based on the comparison between the threshold value SL and the maximum value / minimum value, but the average value AVWIPOS and the allowable value of the average value AVWIPOS are determined. An abnormality diagnosis can be performed based on the comparison with the change area, or an abnormality diagnosis can be performed based on a deviation (change speed) between the previous value and the current value of the threshold value SL or the average value AVWIPOS.

  Further, a rotation detection device configured to determine a condition for rotating the rotation axis forward or reverse, and to set a threshold based on a rotation signal when it is determined that the rotation axis is a forward rotation condition or a reverse rotation condition. The present invention is not limited to the detection of the rotation of the output shaft of the internal combustion engine, but can be applied to the detection of the rotation of the rotation shaft that may be reversed.

Here, technical ideas other than the claims that can be grasped from the above embodiment will be described together with effects.
(A) In the rotation detection device according to claim 1 or 2 ,
Stop position detecting means for detecting a stop position of the internal combustion engine based on the rotation direction of the output shaft ;
Diagnosing means for diagnosing the presence or absence of the threshold abnormality;
Invalid means for invalidating the detection result of the stop position by the stop position detecting means when the diagnosis means diagnoses the occurrence of the threshold abnormality;
It was provided, the rotation detection device.
According to the above invention, when the threshold value shows an abnormal value, the accuracy of forward / reverse rotation determination based on the threshold value is lowered, so that the detection of the stop position of the internal combustion engine performed based on the determination result of forward / reverse rotation is performed. It is invalidated to suppress erroneous detection of the stop position of the internal combustion engine.

(B) In the rotation detecting device according to claim 1 or 2 ,
The rotation signal is generated for each unit rotation angle of the output shaft of the internal combustion engine,
It determines the state of the output shaft rotates forward on the basis of the generation period of the rotation signal, the rotation detecting device.
According to the above invention, when the output shaft (crankshaft) is reversely stopped from the normal rotation state when the internal combustion engine is stopped, the generation period of the rotation signal becomes longer as the rotation direction is reversed. A state in which the output shaft of the internal combustion engine rotates normally is determined based on the generation period.

(C) In the rotation detection device according to claim 1 or 2 ,
The rotary shaft is set both in the threshold to each of the states to reverse the forward states, sets the intermediate value of the threshold as a final threshold, the rotation detecting device.
According to the present invention, the intermediate value between the threshold value set based on the rotation signal in the normal rotation state and the threshold value set based on the rotation signal in the reverse rotation state is set as the final threshold value, so that The determination accuracy can be further improved.

(D) In the rotation detection device according to claim (c),
Setting the final threshold by performing a greater weight to the threshold value set based on the rotation signal in the normal rotation state, the rotation detecting device.
According to the above invention, in the case of an internal combustion engine, since the operation in the reverse rotation state is performed only immediately before stopping, the threshold learning in the reverse rotation state is less frequent than the threshold learning in the normal rotation state. Since the reliability is low, when setting the final threshold from the threshold values obtained during both forward rotation and reverse rotation, the value of the rotation signal in the reverse rotation state is more important by respecting the threshold obtained in the forward rotation state. The threshold can be set with high accuracy while considering the characteristics.

(E) In the rotation detecting device according to claim 1 or 2 ,
Together to measure the pulse width of the rotation signal, based on the moving average value of the measured value, sets the threshold value, the rotation detecting device.
According to the above invention, the moving average of the measurement results of the pulse width or the amplitude of the rotation signal can stably set the threshold value without being influenced by minute fluctuations in the measurement result.

  DESCRIPTION OF SYMBOLS 101 ... Internal combustion engine, 114 ... Engine control unit (ECU), 115 ... Air flow sensor, 117 ... Crank angle sensor, 120 ... Crankshaft (rotary shaft, output shaft), 125 ... Starter switch, 126 ... Intake pressure sensor, 133 ... Cam sensor 134. Cam shaft 173 Battery Battery POS Rotation signal

Claims (2)

Rotation detection that detects the rotation direction of the output shaft by comparing the pulse width of a rotation signal output as a pulse signal with a longer pulse width in the reverse rotation state than the normal rotation state of the output shaft of the internal combustion engine and a threshold A device,
A rotation detection device that changes the threshold according to a pulse width of the rotation signal when the output shaft is rotating forward. A rotation detection device for detecting a rotation direction of the output shaft based on a pulse width of a rotation signal output as a pulse signal having a longer pulse width in a reverse rotation state than a normal rotation state of an output shaft of an internal combustion engine. ,
A rotation detection device that changes a pulse width for determining that the rotation direction of the output shaft is normal rotation based on a pulse width of the rotation signal when the output shaft is in a normal rotation state.