JP6536635B2 - Engine crank angle detection device - Google Patents

Description

  The present invention relates to an apparatus for detecting a crank angle of an engine, and more particularly to an apparatus for detecting a crank angle of an engine including damper means capable of suppressing the occurrence of vibration caused by the engine.

Conventionally, when a misfire occurs in the in-cylinder combustion chamber of the engine, the rotational angular velocity of the explosion stroke decreases, so the rotational angular velocity variation for each explosion stroke of each cylinder is monitored, and this rotational angular velocity variation is determined as a predetermined misfire determination value The presence or absence of a misfire in each cylinder is determined in comparison with.
In general, the rotational angular velocity is in the vicinity of a crank trigger plate attached to a crankshaft which is an output shaft of the engine, a tooth which is a detected portion provided a predetermined number on the outer periphery of the crank trigger plate, and The crank angle is detected by a crank angle detection mechanism configured from a provided rotation angle (crank angle) sensor.

The engine is normally ignited because the rotational angular velocity fluctuation occurs not only due to the combustion condition among the cylinders but also due to mechanical variations such as mounting error of the rotational angle sensor and aging of the teeth. In some cases, a situation may occur that is misjudged as being misfired.
Therefore, during misfire detection, the detected value of the rotational angle between the teeth of the crank trigger plate is learned, the rotational angular velocity of the crankshaft is corrected based on the tolerance set by this detected value, and misfire determination of the engine is performed. There is. By using the tolerance learned by the detection value of the rotation angle sensor, mechanical variations can be eliminated.

The multi-cylinder internal combustion engine misfire diagnosis device of Patent Document 1 determines the presence or absence of a misfire based on the measured period, and a period measuring means for measuring the period based on the detected value of the rotation angle sensor. A misfire determination means and a correction value learning means for learning a correction value of the cycle when the engine rotational speed shows a steady decrease change during deceleration fuel cut are corrected based on the learned correction value. Misfire determination is performed using this cycle.
Thus, the misfire determination is performed during the decelerating fuel cut to eliminate the variation related to the combustion state, and the periodic variation is learned to remove the mechanical variation.

By the way, in a power transmission mechanism such as an automatic transmission mechanism or a manual transmission mechanism mounted on a vehicle, a damper mechanism is used as a dynamic vibration absorber that attenuates vibration in order to reduce torsional vibration of a drive system caused by engine torque fluctuation. Being served.
As shown in FIG. 7A, a plurality of damper mechanisms arranged in the circumferential direction at equal intervals on the outer peripheral side of the lock-up clutch for reducing the vibration due to the drive source by bending in the rotational direction when the lock-up clutch is engaged. The damper spring 51 of FIG.
These damper springs 51 are circumferentially supported at one end in the circumferential direction by the receiving portion 52a of the spring receiving member 52 extending radially outward from the clutch drum, and are connected to the turbine hub and hold the outer peripheral portion of the damper spring The other end portion in the circumferential direction is supported by the receiving portion 53a of the spring holding plate 53 in a contact manner.
Thus, when torque is transmitted from the engine, the damper spring 51 is bent and the spring receiving member 52 is rotated in the rotational direction (see FIG. 7B). Further, the damper spring 51 is stuck by being pushed in the outer peripheral direction by the centrifugal force.

Patent No. 2943045

  An engine provided with a misfire diagnosis device that performs misfire determination using a cycle corrected based on a periodically learned correction value (tolerance) as in the multi-cylinder internal combustion engine misfire diagnosis device of Patent Document 1 Even if the damper means for suppressing the generation of vibration is mounted to suppress the torque fluctuation of the engine, the vibration of the specific frequency may be generated due to the structural factor of the damper means itself, and the misfire of the engine may be erroneously detected. There is.

As a result of the present inventor's investigation, when it is operated in a high load state before the deceleration fuel cut start, the bending speed of the damper spring 51 held by the spring holding plate 53 is under the influence of the centrifugal force acting on the damper spring 51. Since the rotational speed of the clutch drum is faster than this, after the circumferential end of the damper spring 51 and the receiving portion 52a of the spring receiving member 52 are separated once, the damper spring 51 is pressed in the outer peripheral direction.
When fuel cut is started from that state, the engine torque decreases, so that the damper spring 51 returns from the separated state and one circumferential end of the damper spring 51 collides with the spring receiving member 52, so-called cycle It has been found that the dynamic movement phenomenon occurs (see FIG. 7 (c)), and that this periodic movement phenomenon causes a resonance state in which the components around the damper spring 51 resonate.

That is, if the damper spring 51 is moved away from the spring receiving member 52 and operated in a high load state before the start of the decelerating fuel cut, a resonance induction state occurs in which the damper spring 51 sticks to the outer peripheral side. It will occur.
Then, when resonance occurs, the tolerance learning of the crank angle is mislearned during the deceleration fuel cut. Therefore, it has been found that the misfire of the engine is erroneously detected when the misfire is detected using the tolerance learning.

  An object of the present invention is to provide a crank angle detection device or the like of an engine capable of avoiding erroneous detection of a rotational state of a crankshaft.

The crank angle detection device for an engine according to claim 1 includes damper means capable of suppressing generation of vibration caused by the engine, rotation state detection means for detecting a rotation state of a crankshaft, and detection values of the rotation state detection means. A crank angle detection device of an engine including correction means for correcting a state control value related to a rotation state based on operation state determination means for determining an operation state causing resonance by the damper means; detection of the rotation state detection means The correction means corrects the state control value based on the tolerance set by the detected value during the deceleration fuel cut, and the engine load has a predetermined value before the start of the deceleration fuel cut. In the above case, it is characterized in that the learning is limited on the assumption that the resonance induction state is determined .

Since the crank angle detection device of this engine has the operating state judging means for judging the operating state which induces the resonance by the damper means, the resonance inducing state in which the component around the damper spring resonates by the periodic movement phenomenon. Can be determined.
The correction means limits the correction of the state control value when the resonance-induced state is determined by the operation state determination means, thereby avoiding erroneous detection of the rotational state caused by the structural factor of the damper means itself. It is possible to correct the state control value with high accuracy.
In addition, it has a learning means for learning the detection value of the rotation state detection means, and the correction means corrects the state control value based on the tolerance set by the detection value during the deceleration fuel cut, and Before the start, when the engine load is equal to or more than a predetermined value, the erroneous learning of the rotational state due to the structural factor of the damper means itself is avoided, since the learning is considered on the assumption that the resonance induced state is determined. In the decelerating fuel cut in which the output torque transmitted from the engine is small, it is possible to avoid the erroneous learning of the rotational state due to the structural factor while eliminating the variation relating to the combustion state.

In the invention of claim 2, according to the invention of claim 1 , the correction means is operated when a state equal to or greater than a predetermined value of the engine load is detected before the start of the deceleration fuel cut and the engine speed is less than the set value. It is characterized in that the limitation of the learning is canceled on the assumption that the resonance induction state is cancelled.
According to this configuration, it is possible to correct the state control value based on the tolerance in the state where the resonance induction state is released.

According to the invention of claim 3, in the invention of claim 1 or 2 , the correction means corrects the state control value when a deceleration fuel cut execution condition is satisfied and the state other than the resonance induction state is established. It is characterized.
According to this configuration, during deceleration fuel cut, it is possible to correct the state control value with high accuracy while eliminating the variation related to the combustion state.

The invention of claim 4 is the invention according to any one of claims 1 to 3 , further comprising: a misfire detection means for detecting a misfire of the engine based on a detection value of the rotation state detection means; After completion of correction of the state control value by the correction means, misfire detection is performed.
According to this configuration, misfire detection of the engine accompanying learning after crank angle tolerance can be avoided.

  According to the crank angle detection device of the engine of the present invention, it is possible to avoid the erroneous detection of the rotational state of the crankshaft while reducing the torsional vibration of the drive system caused by the torque fluctuation of the engine.

FIG. 1 is a partial cross-sectional view showing an entire configuration of a power train according to a first embodiment. It is a perspective view of a damper mechanism. It is a time chart concerning a definite study value setting. It is an area graph concerning a predetermined learning execution condition. It is a time chart which concerns on another learning execution condition. It is a flowchart which shows a learning value setting process. It is the principal part enlarged view of a damper mechanism, Comprising: (a) is an initial state, (b) is the operating state at the time of normal, (c) has shown the operating state at the time of periodical movement phenomenon occurrence.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.
The following description exemplifies the application of the present invention to a powertrain of a vehicle, and does not limit the present invention, its application, or its application.

  Hereinafter, Example 1 of the present invention will be described based on FIGS. 1 to 6.

As shown in FIG. 1, a powertrain P according to the present embodiment includes an engine 1 which is an internal combustion engine, a torque converter 2 which is a fluid transmission mechanism (automatic transmission mechanism), control of the engine 1 and misfire determination of the engine 1 ECU (Electric Control Unit) 10 and the like for performing
The engine 1 is a gasoline engine in which first to fourth cylinders arranged in series are formed, and each of the first cylinder, the third cylinder, the fourth cylinder, the second cylinder is arranged every 180 ° CA (crank angle). Fuel supply and ignition are set to be performed in the order of cylinders.

First, the engine 1 will be described.
In each cylinder, the engine 1 has an intake valve (not shown) for supplying intake air into a combustion chamber (not shown), a fuel injection valve (not shown) for injecting fuel toward the combustion chamber, and air. A spark plug (not shown) for igniting a mixture of fuel, a piston (not shown) for reciprocating motion, a crankshaft 3 (crankshaft) rotated by the reciprocating motion of the piston, and the crankshaft 3 are accommodated A crankcase (not shown) and an exhaust valve (not shown) for discharging exhaust gas generated by the combustion of the air-fuel mixture in the combustion chamber to an exhaust passage (not shown) are respectively provided.

As shown in FIG. 1, the engine 1 has an opening degree sensor 4 for detecting an accelerator opening degree (throttle valve opening degree) of the engine 1 and a rotation angle sensor 5 for detecting a rotation state including a rotation angle of the crankshaft 3 ( Rotational state detection means), a torque sensor 6 for detecting an output torque corresponding to the load of the engine 1 is provided, and the measured values of the respective sensors are respectively output to the ECU 10.
A crank trigger plate (not shown) is attached to the crankshaft 3, and teeth (not shown) as detected parts are respectively provided at predetermined positions (for example, BTDC 102 deg and ATDC 78 deg) on the outer periphery of the crank trigger plate. .
The rotation angle sensor 5 is installed at a position close to the teeth of the crank trigger plate, and detects an elapsed time (hereinafter referred to as a rotation time) T from the first detection timing to the next detection timing. The rotation speed and the rotation cycle of the engine 1 are calculated from the rotation time T, respectively.

Next, the torque converter 2 will be described.
As shown in FIG. 1, the torque converter 2 is connected in its entirety to the crankshaft 3 via a crank bolt and is configured to be drivable by the engine 1.
The torque converter 2 includes a pump 21, a turbine 22, a stator 23, a one-way clutch 24, a lockup clutch 25, damper springs 26 and 27, a case 28 containing these components, and a damper mechanism D The case 27 is filled with oil which is a power transmission fluid.

The damper springs 26 and 27 bend in the rotational direction when the lockup clutch 25 is engaged, and are configured to be able to reduce the vibration by the engine 1 (crankshaft 3).
As shown in FIG. 2, a plurality of damper springs 26 and 27 are disposed at equal intervals in the circumferential direction, respectively, and provided so as to overlap each other in the axial direction.
As shown in FIG. 1, the damper spring 26 is formed integrally with the clutch drum 29 and has a circumferential end portion abutting on a receiving portion 30a provided on a spring receiving member 30 extending radially outward from the clutch drum 29 The other end in the circumferential direction is supported so as to be in contact with a receiving portion 31 a provided on a spring holding plate 31 which is supported and covers the outer periphery of the damper spring 26.

The spring holding plate 31 is connected at its inner peripheral end to the turbine hub 32 via a rivet and is elastically connected in the rotational direction via the spring receiving member 30 and the damper spring 26. Thus, when the lockup clutch 25 is engaged, the rotation of the crankshaft 3 is input to the spring receiving member 30 via the lockup clutch 25 and transmitted to the spring holding plate 31 (turbine hub 32) via the damper spring 26. Ru.
The damper spring 27 is provided at a radially middle portion of the spring holding plate 31 and has a torsional spring rigidity higher than that of the damper spring 26. As a result, it is possible to widen the twist operation angle, and damp the vibration of the drive system caused by the torque fluctuation of the engine 1.
Therefore, the damper springs 26, 27, the spring receiving member 30, the spring holding plate 31 and the like correspond to the damper mechanism D.

Next, the ECU 10 will be described.
The ECU 10 calculates the angular velocity ω (state control value) of the crankshaft 3 based on the detection value of the rotation angle sensor 5, and the angular acceleration Δω corresponding to the angular velocity fluctuation of the angular velocity ω is the misfire determination threshold α or more. It is determined that When a misfire of the engine 1 is determined, for example, notification to the occupant (lighting of a warning light or warning), stopping of fuel supply to the misfire target cylinder, and the like are performed.

The ECU 10 is configured of a central processing unit (CPU), a ROM, a RAM, an in-side interface, an out-side interface, and the like.
As shown in FIG. 1, the ECU 10 includes a learning unit 11 (learning unit), a driving condition determination unit 12 (driving condition determination unit), a correction unit 13 (correction unit), and a misfire detection unit 14 (misfire detection unit). Etc.

First, the learning unit 11 will be described.
The learning unit 11 calculates the period ratio r corresponding to the tolerance of the crank angle detection mechanism using the rotation time T detected by the rotation angle sensor 5, and when the learning execution condition is satisfied, the determined period ratio r It is set to the definite learning value R. Assuming that the previous rotation time is Tn−1 and the current rotation time is Tn (2 ≦ n), the period ratio r is calculated by the following equation (1).
r = Tn-1 / Tn (1)
The period ratio r is calculated regardless of whether the learning execution condition is satisfied.

The learning execution conditions are the following seven conditions.
(1) After the deceleration fuel cut, a predetermined number of ignitions has elapsed (2) The brake pedal is turned off (brake switch · off)
(3) The fluctuation of the cycle ratio r is small (4) The number of rotations of the engine 1 is within a predetermined range (5) The vehicle speed is within a predetermined range (6) The intake air amount charging efficiency is within the predetermined range Certain (7) that the learning prohibition flag F is 0 If any of these conditions is not satisfied, learning is prohibited.

Although the region where the rotational fluctuation of the crankshaft 3 is large is basically excluded under the above condition (3), in order to remove noise of the periodic ratio r which is generated for some reason, the learning unit 11 The raw values of are removed by the first-order filter f1 to calculate the temporary learning value f2.
In addition, since the periodic ratio r may not converge to the true value of the learning value even when noise is removed, the learning unit 11 performs the stability determination process.
In the stability determination process, the provisional learning value f2 and four cycles (for example, 2 sec) fall within a predetermined range during a predetermined period with a set of weighted average values, and acquire learning values continuously during deceleration fuel cut. Then, it is judged whether or not learning is complete on condition that weighted averaging processing, convergence exclusion condition is satisfied (weighted average value increases or decreases uniformly, or fluctuation range is equal to or more than a predetermined threshold). .

As shown in FIG. 3, the noise removal process is started from time t0 when the learning execution condition is satisfied, and the stability determination process is started from time t1. In the stability determination process, the sample delay period for sampling is from time t1 to time t2, and the actual sampling period is from time t2 to time t3.
The learning unit 11 determines the coincidence state of the periodic ratio r and the temporary learning value f2 twice (r1, r2), and sets the periodic ratio r corresponding to the second coincidence point r2 as the definite learning value R.

In the condition (4), the non-resonance region in which resonance does not occur is set in advance by the number of revolutions because of the structure of the engine 1.
As shown in FIG. 4, the non-resonance region can be set by an operation region defined by the engine speed and the angular velocity fluctuation primary component. In the present embodiment, an operating range in which the engine rotational speed is, for example, 1600 to 1800 rpm and 2900 rpm or more is a non-resonance range, that is, a so-called learning executable range.

Next, the driving state determination unit 12 will be described.
The operating state determination unit 12 determines that the engine is in the decelerating fuel cut execution region based on the operating state of the engine 1, for example, when the engine speed is equal to or higher than a predetermined value and the decelerating operating state.
Further, the operation state determination unit 12 determines the resonance induction state based on the operation state of the engine 1 and sets the learning prohibition flag F to one.

In an operating region where a centrifugal force acts on the damper spring 26, a resonance induced state in which the damper spring 26 separates from the receiving portion 30a of the spring receiving member 30 and sticks to the outer peripheral side when operated under high load before starting deceleration fuel cutting. When decelerating fuel cut starts from there, a periodic movement phenomenon may occur in which one circumferential end of the damper spring 26 collides with the receiving portion 30a of the spring receiving member 30, and this periodic movement phenomenon is resonant Generate a condition.
Then, when resonance occurs, the tolerance learning of the crank angle is erroneously learned during the deceleration fuel cut. Therefore, when the misfire is detected using the tolerance learning, the engine misfire is erroneously detected.
Therefore, when the resonance induction state is determined, the learning of the period ratio r (calculation of the definite learning value R) is restricted by the driving state determination unit 12 setting the learning inhibition flag F to one.

Specifically, as shown in FIG. 5, during the deceleration fuel cut prior to time ta, when the engine load is less than the learning inhibition load β, the learning inhibition flag F is set to 0.
During the stop of the deceleration fuel cut, in other words, when the engine load is equal to or greater than the learning inhibition load β (for example, 100 Nm) before the start of the next deceleration fuel cut (time tb), the learning inhibition flag F is set to 1. When the engine load is equal to or more than the learning inhibition load β, the resonance induced state occurs due to the influence of the centrifugal force acting on the damper spring 26, and the primary vibration of the crankshaft 3 occurs in the fuel cut state thereafter.

The learning prohibition flag F is set to 0 when an engine load equal to or greater than the learning prohibition load β is detected before the start of the deceleration fuel cut and the engine speed is less than the learning prohibition cancellation rotation γ (for example, 1300 rpm) (time tc) It is set. When the engine speed is less than the learning prohibition release rotation γ, the influence of the centrifugal force acting on the damper spring 26 is reduced, and the resonance induction state is canceled. Note that the learning inhibition cancellation rotation γ is set to less than the minimum value of the non-resonance region (in the present embodiment) other than the non-resonance region (see FIG. 4) in which no resonance occurs.
While the deceleration fuel cut is stopped, the learning inhibition flag F is set to 1 when the engine load is equal to or greater than the learning inhibition load β (time td).
Thereafter, even if the deceleration fuel cut execution condition is satisfied (time te), the learning prohibition flag F is maintained at 1 unless the resonance induction state is resolved.

Next, the correction unit 13 will be described.
The correction unit 13 executes the correction of the angular velocity ω used for the misfire determination of the engine 1 when the learning prohibition flag F is zero, and limits the correction of the angular velocity ω when the learning prohibition flag F is one.
The correction unit 13 considers that the resonance induction state is canceled when the learning prohibition flag F is 0, and that the resonance induction state is determined when the learning prohibition flag F is 1, so that correction is performed. Whether to execute or not is determined.

The correction unit 13 calculates the angular velocity ω (deg / sec) according to the following equation (2) when the rotation time T and the definite learning value R are used.
ω = 1000 × 180 / T × R (2)
The definite learning value R is used only when calculating the misfire determination angular velocity ω of the engine 1 and is not used except for the calculation of the misfire determination angular velocity ω.

Next, the misfire detection unit 14 will be described.
The misfire detection unit 14 calculates the amount of fluctuation per unit time of the angular velocity ω of the crankshaft 3, that is, so-called angular acceleration Δω, and determines the misfire of the engine 1 when the calculated angular acceleration Δω is greater than the misfire determination threshold α. doing.

Next, the contents of the learning value setting process will be described based on the flowchart of FIG.
Note that Si (i = 1, 2...) Indicates steps for each process.

As shown in the flowchart of FIG. 6, first, at S1, the outputs of the sensors 4 to 6 and various information are read, and the process proceeds to S2.
In S2, the rotation time T is calculated based on the output of the rotation angle sensor 5, and the process proceeds to S3.
In S3, the period ratio r is calculated using the previous rotation time T and the current rotation time T, and the process shifts to S4.

In S4, it is determined whether a learning execution condition is satisfied.
It is determined whether the learning execution conditions of (1) to (7) described above are satisfied. In addition, when there are few rotation speed fluctuations, you may abbreviate | omit the conditions of (4)-(6).
As a result of the determination in S4, if seven learning execution conditions are satisfied, the process proceeds to S5, and if any of the seven learning execution conditions is not satisfied, the process returns to S2.

In S5, after the noise removal process of the periodic ratio r is performed, the stability determination process is performed (S6), and the process proceeds to S7.
In S7, it is determined whether or not the stability determination has been made.
As a result of the determination in S7, when the stability is determined, the process proceeds to S8, and when the stability is not determined, the process ends without completing the learning.

In S8, it is determined whether the decelerating fuel cut is not performed.
If it is determined in step S8 that the decelerating fuel cut is not performed, the process proceeds to step S9.
If it is determined in step S8 that the deceleration fuel cut is being performed, the process returns to step S6 to obtain a learning value again and perform weighted averaging. While the deceleration fuel cut is being performed, the learning values are weighted average values.
In S9, the cycle ratio r which is the final learning value is set to the definite learning value R, and the process is ended.

Next, the operation and effects of the crank angle detection device of the engine 1 will be described.
According to this crank angle detection device, since the operation state determination unit 12 that determines the operation state that induces the resonance by the damper mechanism D is provided, resonance that causes components around the damper spring 26 to resonate due to a periodic movement phenomenon. The evoked state can be determined.
Since correction unit 13 limits the correction of angular velocity ω when the resonance induction state is determined by operation state determination unit 12, correction unit 13 can avoid erroneous detection of the rotation state due to the structural factor of damper mechanism D itself. It is possible to correct the angular velocity ω with high accuracy.

  The damper mechanism D itself has a learning unit 11 that learns the rotation time T of the rotation angle sensor 5, and the correction unit 13 corrects the angular velocity ω based on the period ratio r corresponding to the tolerance set by the rotation time T. It is possible to avoid erroneous learning of the rotational state due to the structural factor of.

  The correction unit 13 performs correction of the angular velocity ω during the deceleration fuel cut, and limits the learning on the assumption that the resonance induction state is determined when the engine load is the learning prohibition load β or more before the start of the deceleration fuel cut. As a result, during the deceleration fuel cut in which the output torque transmitted from the engine 1 is small, it is possible to eliminate the erroneous learning of the rotational state caused by the structural factor while eliminating the variation relating to the combustion state.

  The correction unit 13 considers that the resonance induction state is canceled when the engine speed is lower than the learning prohibition release rotation γ after the state where the engine load is higher than the learning prohibition load β is detected before the start of the deceleration fuel cut. Then, in order to release the limitation of learning, it is possible to correct the angular velocity ω based on the periodic ratio r in the state where the resonance induction state is released.

  The correction unit 13 corrects the angular velocity ω when the deceleration fuel cut execution condition is satisfied and is in a state other than the resonance induction state. Therefore, during the deceleration fuel cut, the angular velocity with high accuracy while eliminating the variation related to the combustion state. Correction of ω can be performed.

  The misfire detection unit 14 detects a misfire of the engine 1 based on the rotation time T of the rotation angle sensor 5, and the misfire detection unit 14 executes misfire detection after the correction unit 13 completes correction of the angular velocity ω. Misfire detection of 1 can be avoided.

Next, a modification in which the embodiment is partially changed will be described.
1) In the above embodiment, an example of the engine provided with the automatic transmission mechanism with the damper mechanism has been described, but the invention may be applied to an engine provided with the manual transmission mechanism with the damper mechanism. It is applicable regardless of and the type.

2) In the above embodiment, an example of the damper mechanism provided with two types of damper springs, a large diameter damper spring and a small diameter damper spring has been described, but at least periodic movement phenomenon by the damper spring and the spring receiving member The damper mechanism may be any damper mechanism that can occur regardless of the type and model of the damper mechanism. For example, it may be a damper mechanism having only a large diameter damper spring, or a damper mechanism in which two types of damper springs of the same diameter and the other damper spring are accommodated in one damper spring.

3) In the above embodiment, although the example in which the state control value to be corrected is the angular velocity has been described, at least the state control value regarding the rotation state may be used, and various state control such as angular acceleration, rotation period, period ratio, etc. It can be applied to the value.

4) In addition, those skilled in the art can carry out the embodiments in which various modifications are added to the embodiments or a combination of the embodiments without departing from the spirit of the present invention, and the present invention can be implemented as such It also includes various modifications.

Reference Signs List 1 engine 3 crankshaft 5 rotation angle sensor 11 learning unit 12 operation state determination unit 13 correction unit 14 misfire determination unit D damper mechanism

Claims (4)

Damper means capable of suppressing the generation of vibration caused by the engine, rotation state detection means for detecting the rotation state of the crankshaft, and correction means for correcting the state control value regarding the rotation state based on the detection value of the rotation state detection means And an engine crank angle detection device,
Operating condition determining means for determining an operating condition which induces resonance by the damper means ;
And learning means for learning the detection value of the rotational state detection means ,
The correction means corrects the state control value based on the tolerance set by the detected value during the deceleration fuel cut, and determines the resonance induction state when the engine load is equal to or more than the predetermined value before the start of the deceleration fuel cut. An engine crank angle detection device characterized by limiting the learning in view of the above . The correction means considers that the resonance induction state is canceled when the engine rotational speed is less than the set value after the state of the engine load is detected before the deceleration fuel cut starts and the engine induced speed is less than the set value. The crank angle detection device for an engine according to claim 1, wherein the restriction of (1) is released . The engine crank angle detection according to claim 1 or 2, wherein the correction means corrects the state control value when a deceleration fuel cut execution condition is satisfied and in a state other than the resonance induction state. apparatus. It has a misfire detection means for detecting a misfire of the engine based on the detection value of the rotation state detection means,
The crank angle detection device for an engine according to any one of claims 1 to 3, wherein the misfire detection means executes misfire detection after completion of the correction of the state control value by the correction means .