JP2003232255A - Reverse rotation detection device and cylinder discrimination device for internal combustion engine - Google Patents

Abstract

(57) Abstract: In a configuration in which a cylinder determination value is updated at each cylinder determination timing detected based on a position signal POS from a crank angle sensor when a cam sensor that outputs a cylinder determination signal fails, the engine is stopped. This prevents the cylinder discrimination value from being erroneously updated when the swingback occurs. A position signal POS is set to be lost for each stroke phase difference between cylinders, and a cylinder determination value is updated at each cylinder determination timing set based on the detection of a missing position. When the update is performed, the update is stopped. The swing back is detected based on the cycle of the position signal POS or the ratio between the current value and the previous value of the cycle, and in order to prevent erroneous detection at the missing portion,
A threshold value to be compared with the period or the period ratio is switched depending on whether or not the position is a missing position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reverse rotation detecting device for detecting reverse rotation (sway back) when an engine is stopped, and a cylinder determining device for performing cylinder determination using the reverse rotation detecting device.

[0002]

2. Description of the Related Art Conventionally, as a device for detecting reverse rotation of an engine, as disclosed in, for example, Japanese Patent Application Laid-Open No. 11-117780, the generation cycle of a detection signal at every constant rotation angle is measured, and this cycle There is a device that detects the reverse rotation state of the engine by comparing the ratio between the value and the previous value with a threshold value.

Further, as a cylinder discriminating device for an engine, as disclosed in, for example, Japanese Patent Laid-Open No. 11-257148,
A sensor that outputs a detection signal for each constant crank angle, a crank angle sensor in which a detection signal is missing at each angle corresponding to a stroke phase difference between cylinders, and a cylinder that has a different number of occurrences for each stroke phase difference A cam sensor that outputs a discrimination signal, and detects the missing position of the detection signal of the crank angle sensor from the cycle change of the detection signal or the correlation with the cylinder discrimination signal, and the reference crank angle based on the missing position. There is an apparatus configured to perform cylinder discrimination in which the position is associated with each cylinder based on the cylinder discrimination signal.

[0004]

By the way, as in the above-mentioned Japanese Patent Application Laid-Open No. 11-257148, if the detection signal of the crank angle sensor is provided with a missing portion to detect the reference crank angle position, the crank angle is detected. And the detection of the reference crank angle position can be performed by using one sensor. However, since the period becomes longer in the missing portion of the detection signal, the detection signal is detected as disclosed in JP-A-11-117780. In the configuration in which the reverse rotation is detected based on the comparison between the cycle ratio and the constant threshold value, there is a problem that the reverse rotation state may be erroneously detected in the missing portion.

In the structure for performing the cylinder discrimination as in the above-mentioned Japanese Patent Laid-Open No. 11-257148, even if a failure of the cam sensor (cylinder discrimination sensor) occurs, the cylinder discrimination result is in a pattern following the normal cylinder discrimination result. It is possible to perform the same ignition / cylinder-specific injection as in the normal state by sequentially updating the ignition switch and the ignition switch to the OF
If the cylinder discrimination result is stored and held during the period of F, the cylinder discrimination can be performed without restarting the cam sensor even when the engine is restarted.

However, if a reverse rotation (sway back) occurs immediately before the engine is stopped, the cylinder discrimination result may be erroneously updated, and if the cylinder discrimination result is erroneously updated, it may be erroneous at the time of restart. The cylinder discrimination result is sequentially updated with the cylinder discrimination result as an initial value, which causes a problem that restart cannot be performed. Therefore, an object of the present invention is to provide a device capable of accurately detecting the reverse rotation of the engine from the detection signal of the crank angle sensor even if the detection signal of the crank angle sensor is provided with a gap.

Another object of the present invention is to provide a cylinder discriminating device which can correctly discriminate a cylinder by using the reverse rotation detecting device even when a cam sensor for generating a cylinder discriminating signal fails.

[0008]

Therefore, a reverse rotation detecting device according to a first aspect of the present invention is configured such that a detected portion for every fixed angle is omitted at a predetermined crank angle position with respect to a rotating body pivotally supported by a crankshaft of an engine. A crank angle sensor for detecting the detected portion and generating a detection signal, and obtaining a generation cycle of the detection signal and / or a ratio of a current value and a previous value of the generation cycle, the generation cycle and The configuration is such that reverse rotation of the engine is detected based on the comparison between the cycle ratio and the threshold value, and the threshold value is set to a different value depending on whether or not the missing position is detected.

According to the above configuration, it is determined that the cycle of the detection signal of the crank angle sensor is extended by the reverse rotation based on the comparison between the cycle and / or the cycle ratio and the threshold value. Since the cycle becomes long irrespective of the reverse rotation, the threshold value for detecting the reverse rotation is set to a different value at the missing position and other values so that the cycle extension due to the missing and the cycle extension due to the reverse can be distinguished.

A cylinder discriminating apparatus according to a second aspect of the present invention is the first aspect of the present invention.
A reference crank that includes a reverse rotation detection device for an internal combustion engine as described above, and includes a cam sensor that extracts a cylinder determination signal from a camshaft of the engine, and a reference crank that uses the missing position as a reference based on the cylinder determination signal from the cam sensor. Along with performing cylinder discrimination in which the angular position is associated with each cylinder, when the cam sensor malfunctions, the cylinder discrimination result is updated by using the detection of the missing position as a trigger in a pattern subsequent to the normal cylinder discrimination result, Moreover, when the reverse rotation of the engine is detected, the updating of the cylinder discrimination result is stopped.

According to the above configuration, the cylinder discrimination is made based on the cylinder discrimination signal from the cam sensor so that the reference crank angle position corresponds to each cylinder. However, even if the cam sensor fails, the cylinder discrimination result can be obtained by repeating the pattern so far. Since it may be updated, the cylinder determination result is updated by using the detection of the missing position as a trigger, and the cylinder determination result is not updated when reverse rotation is detected based on the cycle / cycle ratio of the detection signal.

A reverse rotation detecting device according to a third aspect of the present invention forms a detected portion at a constant angle with respect to a rotating body pivotally supported by a crankshaft of an engine, and detects the detected portion to detect a detection signal. As a detection element that generates a signal, two detection elements whose detection signals are out of phase with each other are provided, and the difference between the detection signals from the two detection elements is obtained, and the difference detection signal and the determination value for rising and the rising A configuration that has a crank angle sensor that generates a pulse wave by comparison with a determination value for lowering and outputs the pulse wave as a final detection signal, and detects reverse rotation of the engine based on the duty ratio of the detection signal. And

According to the above structure, the crank angle sensor is
It is configured to include two detection elements (for example, Hall elements) whose phases are shifted, and the presence or absence of inversion is detected based on the duty ratio when the difference between the detection signals of the detection elements is converted into a pulse wave. That is, the differential output of the detection element is converted into a pulse wave by comparing the upper and lower two threshold values (a rising judgment value and a falling judgment value), and the rising or falling of the pulse wave is detected. Although it is at the detection position, when the rotation direction is reversed, the on / off of the pulse wave is reversed, so that the duty ratio (O per cycle)
N or OFF time ratio) will change greatly.

For example, when a part of the detection signal of the crank angle sensor is missing, the duty ratio (ON time ratio) other than the missing part at the time of forward rotation is 30%, and it is 10% at the missing part, At the time of reverse rotation, the respective duty ratios are switched to 70% and 90%, so the reverse rotation is detected by the inversion of the duty ratio. A cylinder discriminating apparatus according to a fourth aspect is configured to include the reverse rotation detecting apparatus for an internal combustion engine according to the third aspect, and the detected portion of the crank angle sensor is missing at a predetermined crank angle position, while A cam sensor for extracting a cylinder discrimination signal from the camshaft of the engine is provided, and cylinder discrimination is performed based on the cylinder discrimination signal from the cam sensor so that a reference crank angle position based on the missing position corresponds to each cylinder, and the cam sensor outputs At the time of failure, the cylinder discrimination result is configured to be updated by using the detection of the missing position as a trigger in a pattern following the normal cylinder discrimination result, and when reverse rotation of the engine is detected, the cylinder discrimination result Configured to stop the update.

According to the above construction, the cylinder discrimination is made based on the cylinder discrimination signal from the cam sensor so that the reference crank angle position corresponds to each cylinder. However, even if the cam sensor fails, the cylinder discrimination result can be obtained by repeating the pattern so far. Since it may be updated, the cylinder discrimination result is updated with the detection of the missing position as a trigger, and the cylinder discrimination result is not updated when reverse rotation is detected based on the duty.

In the cylinder discriminating apparatus according to a fifth aspect of the present invention, the cylinder discrimination result is updated when the number of detection signals generated after the missing position is detected reaches a predetermined value. After the reverse rotation is detected, the update is stopped at the update timing. According to the above configuration, the cylinder discrimination result is updated when the number of detection signals generated after the missing position is detected reaches a predetermined value.
Even if the reverse rotation is detected, the number of detection signals generated is counted up, so that the update timing is detected and the cylinder discrimination result is updated. Even if is a value indicating the update timing, the update is stopped.

[0017]

According to the first aspect of the present invention, in the structure for detecting the reverse rotation based on the cycle and / or cycle ratio of the detection signal of the crank angle sensor, it is determined whether the detection signal is missing at the reverse rotation detection threshold value. Since there is no erroneous detection of the extension of the cycle due to the loss of the signal as the reverse rotation, the reverse rotation can be accurately detected from the detection signal of the crank angle sensor which also detects the reference crank angle position. .

According to the second aspect of the present invention, even if the cam sensor fails, the cylinder discrimination result can be continuously updated by updating the cylinder discrimination result in a normal pattern, while the cylinder discrimination can be continued. There is an effect that the cylinder discrimination result is not updated by mistake, and the ignition control or the like can be performed based on the correct cylinder discrimination result at the time of restart.

According to the third aspect of the invention, the on / off state of the pulse wave generated by comparing the differential output of the two detection elements with the rising judgment value and the falling judgment value is the reverse rotation of the engine. Since the reverse rotation of the engine is detected based on the fact that the reverse rotation causes the duty ratio to switch and the reverse rotation of the engine is detected, even if the detection signal of the crank angle sensor is missing, reverse rotation detection that is not affected by the missing can be performed. There is.

According to the fourth aspect of the present invention, even if the cam sensor is out of order, the cylinder discrimination result can be continuously updated by updating the cylinder discrimination result in a normal pattern, while the cylinder discrimination can be continued. Since the reverse rotation is not erroneously detected due to the missing portion of the crank angle sensor output provided for detecting the angular position, and the cylinder determination result is not updated by the reverse rotation, the correct cylinder determination result at restart is obtained. There is an effect that ignition control and the like can be performed based on the above.

According to the fifth aspect of the present invention, the cylinder discrimination result is prevented from being erroneously updated at the time of reverse rotation, even if the update timing of the cylinder discrimination result is detected irrespective of forward rotation / reverse rotation. Therefore, there is an effect that the ignition control and the like can be performed based on the correct cylinder discrimination result at the time of restart.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an in-line four-cylinder internal combustion engine for a vehicle according to an embodiment. An intake pipe 102 of an internal combustion engine 101 is provided with an electronically controlled throttle 104 that opens and closes a throttle valve 103b by a throttle motor 103a. Air is sucked into the combustion chamber 106 through the electronically controlled throttle 104 and the intake valve 105.

Combustion exhaust is discharged from the combustion chamber 106 to the exhaust valve 1
It is discharged via 07, purified by the front catalyst 108 and the rear catalyst 109, and then discharged into the atmosphere. The intake valve 105 and the exhaust valve 107 respectively include an intake side camshaft 110A and an exhaust side camshaft 110B.
It is opened and closed by a cam provided on the.

An electromagnetic fuel injection valve 112 is provided in the intake port 111 on the upstream side of the intake valve 105 of each cylinder. The fuel injection valve 112 is an injection pulse signal from an engine control unit (ECU) 113. When the valve is driven to be opened by, the fuel adjusted to a predetermined pressure is injected toward the intake valve 105. The air-fuel mixture formed in the cylinder is ignited and burned by spark ignition by the spark plug 114.

Each ignition plug 114 has an ignition coil 115 containing a power transistor therein.
The ECU 113 controls ignition timing (ignition advance value) by switching control of the power transistor. The ECU 113 includes an accelerator pedal sensor APS116, an air flow meter 115 for detecting the intake air amount Q of the engine 101, a crank angle sensor 117 for extracting a position signal POS for each unit crank angle from the crankshaft 121, and an opening TVO of the throttle valve 103b. A throttle sensor 118 for detecting the temperature, a water temperature sensor 119 for detecting a cooling water temperature Tw of the engine 101, and the intake side camshaft 110A.
Cam sensor 12 for extracting the cylinder discrimination signal PHASE from the
A detection signal from 0 or the like is input.

The cam sensor 120 has a camshaft 11 that rotates twice each time the crankshaft 121 rotates once.
In the four-cylinder engine 101, the detected portions with different numbers of ridges are provided at every 90 ° around the periphery of the signal plate (rotating body) pivotally supported by 0A, and the detected portions are detected by the hall element or the electromagnetic pickup. Different (1 to 4) pulse signals are generated as the cylinder discrimination signal PHASE for each crank angle 180 ° CA corresponding to the stroke phase difference between the cylinders (see FIG. 2).

Further, the crank angle sensor 117 has a protrusion (detected portion) formed for each crank angle of 10 ° CA on the periphery of the signal plate 122 integrally provided with a drive plate or the like pivotally supported by the crankshaft 121. On the other hand, as shown in FIG. 3, two Hall elements 201A and 201B are provided as sensors for detecting the protrusions.

The two Hall elements 201A and 201B
Is the signal plate 122 as shown in FIG.
Of the Hall elements 201A and 201B (S1-S2).
S2) is obtained, and the difference output is compared with the rising determination value Sup and the falling determination value Sdo (<Sup), so that when the rising determination value Sup is crossed upward, it rises, Converting the falling judgment value Sdo into a pulse wave that falls when crossing downward,
This is output as the position signal POS.

In addition, the protrusion 202 is formed into the BT of each cylinder.
It is made to be missing at positions corresponding to DC 60 ° and BTDC 70 °, and only two consecutive position signals POS are missing every 180 ° (see FIG. 2). Furthermore,
The position of the head pulse of the cylinder discrimination signal PHASE output for each crank angle of 180 ° CA and the missing position of the position signal POS are aligned (see FIG. 2).

In the above-mentioned structure, the ECU 113 generates the reference crank angle signal REF based on the signals from the cam sensor 120 and the crank angle sensor 117 and determines the cylinder corresponding to the reference crank angle signal REF. The ignition timing and fuel injection timing of each cylinder are controlled based on the reference crank angle signal REF.

Details of the generation of the reference crank angle signal REF and the cylinder discrimination will be described below with reference to the flowcharts of FIGS. The flow charts of FIGS. 4 and 5 are
The program executed by interruption every time the position signal POS is generated (falling of the position signal POS) is shown. In step S1, the generation cycle of the position signal POS (time from the fall of the position signal POS to the fall) TPOS is measured.

In step S2, the latest measurement cycle TPO
The ratio TPOSCP between S and the previous value TPOSz is calculated. TPOSCP = TPOS / TPOSz In step S3, the latest measurement cycle TPO is determined by determining whether or not the cycle ratio TPOSSCP exceeds the threshold value A.
It is determined whether S is the result of measuring the missing portion.

If the cycle ratio TPOSSCP exceeds the threshold value A, it is determined that the latest measurement cycle TPOS is the result of measuring the missing portion, and the process proceeds to step S4 to set 1 to the missing detection flag Fnu. On the other hand, when it is determined in step S3 that the cycle ratio TPOSCP is less than or equal to the threshold value and the latest measurement cycle TPOS is a measurement result other than the missing portion, the process proceeds to step S5, and the missing detection flag Fnu is 1. Or not.

If the position signal POS is generated immediately after measuring the missing portion, it is determined that Fnu = 1, and if it is determined that Fnu = 1, the process proceeds to step S6. After resetting the flag Fnu to 0, the process proceeds to step S7, and the count value CRACNT of the position signal POS is reset to 0. On the other hand, when it is determined that the latest measurement cycle TPOS is the measurement result of the missing portion, the flag Fnu is set to 1 in step S4, and the flag Fnu is determined to be 0 in step S5. , And proceeds to step S8 to increment the count value CRACNT by one.

By the above control, the count value CRAC
NT is counted up each time the position signal POS is generated, and is reset to 0 (at the position of BTDC 40 °) when the position signal POS is generated immediately after measuring the missing portion (see FIG. 2). When the count value CRACNT is incremented in step S8,
In step S9, it is determined whether the count value CRACNT is 7.

The count value CRACNT = 7 is set as the cylinder discrimination timing (see FIG. 2), and if the count value CRACNT = 7, the process proceeds to step S10 to make the cylinder discrimination. In step S10, it is determined whether the cam sensor 120 is out of order. The failure of the cam sensor 120 means a state in which the cylinder discrimination signal PHASE is not generated due to disconnection or short circuit.

When it is determined in step S10 that the cam sensor 120 is normal, the process proceeds to step S11,
Every time the cylinder discrimination signal PHASE is generated, the cylinder discrimination is performed based on which of the count values CAMCNT counted up in step S21 of the flowchart of FIG. In step S12, the count value CAMCNT is reset to 0 and the count value CRA is reset again.
Cylinder discrimination signal PHA until CNT = 7
The number of SE occurrences should be counted.

On the other hand, in step S10, the cam sensor 120
If it is determined that the engine is out of order, the process proceeds to step S13, and it is determined whether or not the swing-back (reverse rotation) when the engine is stopped is detected. If the swing-back is not detected, the process proceeds to step S14, and the cylinder discrimination result is updated based on the previous cylinder discrimination result.

In the four-cylinder engine 101 of the present embodiment, if the ignition order is # 1 cylinder → # 3 cylinder → # 4 cylinder → # 2 cylinder, for example, when the previous cylinder discrimination result is # 3 cylinder. In this case, the # 4 cylinder may be updated this time according to the ignition order pattern. Even if the cam sensor 120 fails in the middle, the count value CRACNT becomes 7 every time in the pattern following the normal cylinder discrimination result. The cylinder discrimination result can be updated.

In step S15, the update result of the cylinder discrimination this time is backed up for the next cylinder discrimination and to hold the update result while the ignition switch is OFF. Therefore, when the cam sensor 120 is restarted with the malfunction, the engine 101 can be operated by sequentially updating the cylinder discrimination based on the last cylinder discrimination result during the previous operation.

On the other hand, if it is determined in step S13 that swingback (reverse rotation) when the engine is stopped is detected, the cylinder determination is updated by bypassing steps S14 and S15 and ending this program. Stop. As a result, when the count value CRACNT = 7 by swinging back (reverse rotation) is reached, it is avoided that the cylinder discrimination is erroneously updated according to the ignition order (see FIG. 7).
Cylinder discrimination can be correctly performed when the engine is restarted while 0 is in a failed state.

In step S9, the count value CRAC
If it is determined that NT = 7, the process proceeds to step S16, and the count value CRACCNT = 11 (BTDC110
°) is determined. Count value CRACNT
= 11 is set as the generation timing of the reference crank angle signal REF, and the count value C is set in step S16.
If it is determined that RACNT = 11, step S1
7, the reference crank angle signal REF is generated.

The reference crank angle signal REF indicates a reference crank angle position serving as a measurement reference for the ignition timing and the fuel injection timing. Based on the cylinder discrimination value at the time when the reference crank angle signal REF is generated, the reference crank angle signal REF Set the ignition timing and fuel injection timing. The swing-back (reverse rotation) detection processing determined in step S13 is performed according to the flowchart of FIG.

The flowchart of FIG. 8 is executed every time the position signal POS is generated (falling of the position signal POS), and in step S31, the generation cycle TPOS of the position signal POS is measured. In the next step S32, it is determined whether or not it is the timing when the count value CRACNT is counted up to 15 according to the flowchart of FIG.

When the count value CRACNT is not 15, the current measurement cycle is a normal crank angle of 10 °.
It takes time to rotate, so step S3
3, the normal value (for example, 20 ms) is set as a threshold value for detecting swing back (reverse rotation) based on the cycle TPOS, and it is determined whether the cycle TPOS is equal to or more than the normal value.

When the period TPOS is equal to or more than the normal value, it is determined that the swing-back (reverse rotation) immediately before the stop causes a long period which does not normally occur, and the process proceeds to step S35 to swing-back (reverse). Determine the occurrence.
On the other hand, if the count value CRACNT is counted up to 15, it means that the missing portion of the position signal POS has been measured in the current measurement cycle, so the process proceeds to step S34, and swings back based on the cycle TPOS. As a threshold value for detecting (reverse rotation), a missing threshold value (for example, 60 ms) longer than the normal value is set, and the cycle T
It is determined whether or not the POS is equal to or more than the threshold value at the time of missing.

When the period TPOS is equal to or more than the threshold value at the time of missing, by swinging back (reverse rotation) immediately before stop,
It is determined that a long cycle, which does not normally occur even if the missing portion is taken into consideration, proceeds to step S35, and it is determined whether rocking back (reverse rotation) occurs. The threshold is
The time is longer than the maximum value of the cycle TPOS when the engine 101 stops without reversing, and the time is set to exceed the first time after the swing back (reverse rotation) occurs, but the occurrence of the swing back (reverse rotation) stops. Since it is limited to the immediately preceding extremely low rotation speed, it is preset as a fixed value.

As described above, when detecting the presence or absence of swing back (reverse rotation) based on the comparison between the cycle TPOS and the threshold value, the time required for the cycle TPOS to rotate by a normal crank angle of 10 ° is determined. Since the threshold value is switched depending on whether it shows or the time required to rotate the crank angle of 30 ° at the missing position, even if swing back (reverse rotation) occurs at the missing position, this can be correctly detected. Yes (see Figure 9).

In the flowchart of FIG. 8 described above, the cycle TP
Although swingback (reverse rotation) is detected based on the OS, the current value TPOS and the previous value TP of the cycle TPOS are detected.
Swing-back (reverse rotation) can be detected based on the ratio TPOSCP with respect to OSz.
An embodiment in which swing back (reverse rotation) is detected based on CP is shown in the flowchart of FIG.

The flow chart of FIG. 10 shows the generation of the position signal POS (falling of the position signal POS).
Interruption is executed every time, and in step S41, the generation cycle TPOS of the position signal POS is measured. In step S42, the current measurement cycle TPOS and the previous value TPOS
Calculate the ratio TPOSCP with z.

TPOSCP = TPOS / TPOSz In the next step S43, it is determined whether or not it is the timing when the count value CRACNT is counted up to 15 according to the flowchart of FIG. When the count value CRACNT is not 15, the current measurement cycle is the time required to rotate the normal crank angle of 10 °, so the routine proceeds to step S44, where the cycle ratio T
A normal value (for example, 2.0) is set as a threshold value when the determination of swing back (reverse rotation) is detected based on the POSCP, and it is determined whether the cycle ratio TPOSSCP is equal to or more than the normal value.

When the cycle ratio TPOSSCP is greater than or equal to the normal value, it is determined that the swing cycle immediately before the stop (reverse rotation) results in a large cycle ratio that does not normally occur, and the process proceeds to step S46 to swing back (reverse rotation). ) Is determined. On the other hand, the count value CRACNT is 15
If it is counted up, it means that the missing portion of the position signal POS has been measured in this measurement cycle, so the process proceeds to step S45, and the cycle ratio TPOSSCP.
As a threshold value for determining the swing-back (reverse rotation) detection based on the above, a missing threshold value (for example, 6.0) larger than the normal value is set, and whether the cycle ratio TPOSSCP is equal to or more than the missing threshold value. Determine whether or not.

When the cycle ratio TPOSSCP is greater than or equal to the missing threshold value, it is judged that the swing cycle (reverse rotation) immediately before the stop results in a large cycle ratio that does not normally occur even if the missing point is taken into consideration. And step S4
Proceed to step 6 to determine the occurrence of swing back (reverse rotation). The threshold value is a value larger than the maximum value of the cycle ratio TPOSSCP when the engine 101 stops without reversing, and is set to a value which exceeds the value only when the swing-back (reverse rotation) occurs. ) Is limited to the extremely low rotation speed immediately before the stop, and is set as a fixed value in advance.

As described above, when the presence or absence of swing back (reverse rotation) is detected based on the comparison between the cycle ratio TPOSSCP and the threshold value, the current cycle T used in the calculation of the cycle ratio TPOSSCP.
The threshold is switched depending on whether the POS indicates the time required to rotate the normal crank angle of 10 ° or the crank angle of 30 ° at the missing position. Even if "reverse rotation" occurs at the missing position, this can be correctly detected (Fig. 1).
1).

Further, in the case of the configuration in which the position signal POS is generated by comparing the differential output of the two Hall elements 201A and 201B with the rising judgment value Sup and the falling judgment value Sdo as in the present embodiment. When swing-back (reverse rotation) occurs, the Hall element that reacts first with respect to the detected portion is replaced, and as shown in FIG. 3B, the position signal PO for the same crank position is generated.
The on / off state of S is reversed.

Therefore, the position signal PO for the cycle
The duty ratio, which is the on-time ratio of S, is reversed between normal rotation and reverse rotation (when swinging back). For example,
The duty ratio other than the missing portion at the time of forward rotation is 30%,
If the missing portion is set to 10%, the respective duty ratios are switched to 70% and 90% during reverse rotation.

Therefore, in the flowchart of FIG. 12, when the interruption is executed every time the position signal POS is generated (falling of the position signal POS), first, at step S51, the duty ratio POS of the position signal POS is set.
Duty is measured, and in the next step S52, it is determined whether or not the duty ratio POSSDuty is larger than the duty ratio in the missing portion at the time of normal rotation and is equal to or more than a threshold value (for example, 50%) that is exceeded by reverse rotation. Determine (FIG. 13).

Then, the duty ratio POS measured this time
If the duty is greater than or equal to the threshold value, it is determined that the duty ratio POS Duty has been inverted by swinging back (reverse rotation), and the process proceeds to step S53 to determine whether swinging back (reverse rotation) has occurred. As described above, the duty ratio POSSDut
If y is the configuration for detecting the occurrence of swing back (reverse rotation),
By properly setting the duty during forward rotation, it is possible to detect the occurrence of swingback (reverse rotation) with a fixed threshold value without determining whether the duty ratio is in the missing portion or not. ) The detection can be easily performed.

In the above embodiment, the detection of the missing position of the POS signal is performed based on the cycle ratio.
The missing position may be detected based on the generation timing of the head signal of the cylinder discrimination signal PHASE, and the detection may be switched to the period ratio detection when the cam sensor fails.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an internal combustion engine according to an embodiment.

FIG. 2 is a time chart showing output characteristics of a crank angle sensor and a cam sensor according to the embodiment.

FIG. 3 is a diagram showing output characteristics of a crank angle sensor in the embodiment.

FIG. 4 is a flowchart showing cylinder discrimination control according to the embodiment.

FIG. 5 is a flowchart showing cylinder discrimination control according to the embodiment.

FIG. 6 is a flowchart showing a cylinder discrimination signal counting process in the embodiment.

FIG. 7 is a time chart showing a characteristic of cylinder discrimination when rocking back occurs in the embodiment.

FIG. 8 is a flowchart showing a first embodiment of swing-back detection.

FIG. 9 is a time chart showing the processing characteristics of the first embodiment.

FIG. 10 is a flowchart showing a second embodiment of swing-back detection.

FIG. 11 is a time chart showing the processing characteristics of the second embodiment.

FIG. 12 is a flowchart showing a third embodiment of swing-back detection.

FIG. 13 is a time chart showing the processing characteristics of the third embodiment.

[Explanation of symbols]

101 ... Internal combustion engine 113 ... Engine control unit 117 ... Crank angle sensor 120 ... Cam sensor 121 ... Crank shaft

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 45/00 F02D 45/00 362Z 17/04 17/04 P F term (reference) 3G084 CA00 CA01 CA07 DA04 DA27 DA30 EA11 EB22 EC02 EC03 FA00 FA36 FA38 FA39 3G092 EA10 EA17 EB04 EB05 FA44 FB02 FB06 GA10 GA20 HE00Y HE03Z HE04X HE05X HF20Z

Claims (5)

[Claims] Claim: What is claimed is: 1. A rotary body pivotally supported by a crankshaft of an engine is formed by cutting off a detected portion at a constant angle at a predetermined crank angle position, and detecting the detected portion to generate a detection signal. A crank angle sensor for determining the generation cycle of the detection signal and / or the ratio of the present value and the previous value of the generation cycle, and comparing the generation cycle and / or cycle ratio with a threshold value to reverse the engine. A reverse rotation detection device for an internal combustion engine, wherein the threshold value is set to a different value depending on whether or not the missing position is detected. 2. A reverse rotation detecting device for an internal combustion engine according to claim 1, further comprising a cam sensor for extracting a cylinder discrimination signal from a camshaft of the engine, wherein the cam sensor extracts a cylinder discrimination signal from the cam shaft of the engine. Cylinder discrimination is performed in which the reference crank angle position based on the missing position is made to correspond to each cylinder, and when the cam sensor malfunctions, the detection of the missing position is triggered in a pattern subsequent to the normal cylinder discrimination result to detect the cylinder discrimination result. A cylinder discriminating apparatus for an internal combustion engine, wherein the cylinder discriminating apparatus is configured to perform updating, and to stop updating of the cylinder discrimination result when reverse rotation of the engine is detected. 3. A detection element that forms a detection portion at a constant angle with respect to a rotating body that is axially supported by a crankshaft of an engine, and that detects a detection signal by detecting the detection portion. By providing two detection elements whose signals are out of phase with each other, the difference between the detection signals from the two detection elements is obtained, and the difference detection signal is compared with the rising judgment value and the falling judgment value. A reverse rotation of an internal combustion engine, which has a crank angle sensor that generates a pulse wave and outputs the pulse wave as a final detection signal, and detects reverse rotation of the engine based on a duty ratio of the detection signal. Detection device. 4. A reverse rotation detecting device for an internal combustion engine according to claim 3, wherein the detected portion of the crank angle sensor is cut off at a predetermined crank angle position, and the crankshaft is removed from a camshaft of the engine. A cylinder sensor for extracting a cylinder discrimination signal is provided, and based on the cylinder discrimination signal from the cam sensor, the cylinder discrimination is performed such that the reference crank angle position based on the missing position corresponds to each cylinder, and when the cam sensor fails, the normal state is detected. In the pattern following the cylinder discrimination result, the cylinder discrimination result is updated by using the detection of the missing position as a trigger, and the update of the cylinder discrimination result is stopped when the reverse rotation of the engine is detected. A cylinder discriminating apparatus for an internal combustion engine, which is configured. 5. The cylinder discrimination result is updated when the number of detection signals generated reaches a predetermined value after the missing position is detected, and after the engine reverse rotation is detected. The cylinder discriminating apparatus for an internal combustion engine according to claim 2, wherein the updating is stopped at the updating timing.