JP3115337B2 - Engine crank angle sensor output correction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine crank angle sensor having a crank angle sensor for detecting a phase of a camshaft and a valve timing changing mechanism for changing a valve timing by changing a phase of the camshaft. The present invention relates to an output correction device.

[0002]

2. Description of the Related Art Conventionally, when a camshaft is driven by an engine valve operating mechanism, a valve timing changing mechanism is mounted on the camshaft driving mechanism to change the rotational phase between the crankshaft and the camshaft. A technique in which the valve timing of an exhaust valve or an intake valve is changed in accordance with the operating state is known, as disclosed in, for example, Japanese Patent Application Laid-Open No. 58-185914.

In the above-mentioned prior art, as a valve timing changing mechanism, for example, for driving a camshaft of a valve operating mechanism, a motor is operated by a slider which moves in a slit formed at an end of the camshaft. A structure that changes the rotational phase between the camshaft and the crankshaft is disclosed.

Further, the ignition timing control of the engine, for performing fuel injection control, in order that control is provided crank angle sensor on the camshaft to detect the phase of the engine rotation, the top dead center The position is detected.

[0005]

However, in an engine in which the above-described crank angle sensor is provided on a camshaft, if the above-described valve timing changing mechanism is installed on the camshaft, the valve timing change mechanism is not used. When the rotation phase of the camshaft changes due to the operation of the mechanism, the detection phase of the crank angle sensor also shifts.

[0006] In contrast to the above, if there is a camshaft whose valve timing is not changed in an engine having a plurality of camshafts, a crank angle sensor may be provided on this camshaft. In the case of (2) or when both camshafts change the valve timing, the detection signal of the crank angle sensor is affected by the operation of the valve timing change mechanism, and the correct engine rotation, that is, the rotation phase of the crankshaft is detected Therefore, there is a problem that the control characteristics of the ignition timing control and the fuel injection control based on this cannot be achieved.

It is also conceivable to install the crank angle sensor directly on the crankshaft instead of the camshaft, for example, so as not to be affected by the valve timing changing mechanism. ,
This is disadvantageous from various conditions such as durability and cost.

In view of the above circumstances, the present invention provides an engine crank angle sensor output correction device which is capable of accurately detecting the operation of a variable valve timing mechanism for a crank angle sensor provided on a camshaft. It is intended to provide.

[0009]

In order to achieve the above object, an engine crank angle sensor output correcting apparatus according to the present invention, as shown in FIG. A crank angle sensor 2 that outputs a TOP signal or the like at a reference position of engine rotation by detecting a rotation phase is installed, and a valve that changes valve timing by changing the phase of the camshaft 1 with respect to rotation of the crankshaft. A timing change mechanism 10 is provided. In addition, the crank angle sensor 2
Is for detecting the engine speed from the rotation speed of the camshaft 1.

The valve timing changing mechanism 1
There is provided a correcting means 6 for correcting the output of the TOP signal from the crank angle sensor 2 in accordance with a change in the phase of the camshaft 1 due to a change in the valve timing due to the operation of 0.

[0011] Further, the crank angle by the correction means 6
For correction of sensor output, refer to Engine Control Unit.
Drive signal from the knit 3 to the valve timing changing mechanism 10
It is preferable to carry out according to the number. That is, the correction means 6
Is a drive signal to the valve timing changing mechanism 10.
From the start of changing the valve timing according to the output, the actual valve
Set the operation time until the end of the
Corresponds to change of valve timing according to operating time
Of the TOP signal output from the crank angle sensor 2
It is assumed that the magnitude of the correction amount is gradually changed.

The TOP signal and the rotation signal Ne corrected by the correction means 6 are input to the engine control unit 3 together with an intake air amount signal Qa (load signal) from an intake air amount sensor 8 for detecting an intake air amount of the engine. You. The engine control unit 3 outputs a control signal to the valve timing changing mechanism 10 in accordance with an operating state such as an engine speed and a load to perform driving for changing the valve timing, and calculates an ignition timing corresponding to the operating state. At a predetermined time, an ignition signal is output to an ignition plug 5 to perform ignition timing control, and a fuel injection amount corresponding to an operating state is calculated, and a fuel injection pulse is output to an injector 4 at a predetermined time to output fuel. Injection control is performed.

Further, the crank angle control by the correction means 6 is performed.
Sensor output correction from the start of valve timing change.
Depending on the operating time until the end of switching the valve timing
To gradually change the magnitude of the correction amount of the TOP signal
By doing so, it is possible to respond to the actual phase change of the camshaft 1.
Correction becomes possible.

[0014] The operation time required until change end of the valve timing at the valve timing during change operation by the variable valve timing mechanism 10, the valve timing
It is possible to correct individual differences and changes over time of the valve timing changing mechanism 10 by performing learning correction by correcting the difference from the set value by detecting from the signal of the operation detecting sensor 7 that detects the operating state of the changing mechanism 10. Becomes

Further, when the valve timing changing mechanism 10 is of an electric drive type, the changing speed of the valve timing changes in accordance with the battery voltage VB.
The battery voltage VB when the valve timing changing mechanism 10 is operated is measured, and the operation set time is corrected according to the measured voltage.
Thus, more accurate correction can be performed.

[0016]

In the engine crank angle sensor output correction device as described above, the output of the crank angle sensor is corrected by the correction means in accordance with the operating state of the valve timing change mechanism, and the correction by the correction means is performed by the actual correction. Bal
In response to the operation of the
By performing gradual response, class corresponding to the phase change of the actual cam shaft due to a change of the valve timing
By correcting the output of the link angle sensor, the actual camshaft
Control signal such as ignition timing control or fuel injection control based on the crank angle detection signal can be obtained according to the valve timing. And the crank angle sensor can be installed on the camshaft, and a lightweight and low-cost crank angle sensor can be used.

In the correction by the correction means ,
By learning and correcting the operation time of the valve timing changing mechanism described above, or by correcting it in accordance with the battery voltage, it is possible to perform correction more accurately corresponding to a phase change of the camshaft.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic plan view of a cylinder head portion of one bank of a V-type engine showing an arrangement example of a valve timing changing mechanism and a crank angle sensor according to one embodiment. FIG. 2 shows only one bank, but the other bank has the same configuration.

In the bank of the V-type DOHC engine, each cylinder is provided with a four-valve structure (two valves on the intake side and two valves on the exhaust side), and intake and exhaust valves (not shown) of each cylinder are provided. A pair of camshafts 1A and 1B on the exhaust side and the intake side of the valve train that opens and closes are rotatably supported above the cylinder head 9 of each bank in parallel with each other. The exhaust side and intake side camshafts 1A,
Cam pulleys 12 and 12 are disposed at one end of the cam pulley 1B, respectively. The cam pulleys 12 and 12 are rotatably driven by a timing belt wound from a crankshaft (not shown).
Valve timing changing mechanisms 10A and 10 for independently changing the valve timing of the exhaust valve and the intake valve between the camshafts 2 and 12 and the respective camshafts 1A and 1B.
B is interposed. A crank angle sensor 2 for detecting the rotational phase of the camshaft 1A to output a TOP signal at a reference position of the engine rotation and detecting the engine speed is connected to the other end of the exhaust side camshaft 1A. Have been.

FIG. 3 shows a valve timing changing mechanism 1 for changing the valve timing of the exhaust side camshaft 1A.
It is a cross-sectional view of FIG. 0A, and the structure of the valve timing changing structure 10B with respect to the intake side camshaft 1B is basically the same.

The valve timing changing mechanism 10A is mounted on the tip of the camshaft 1A, and a cam pulley 12 to which power from a crankshaft (not shown) is transmitted is provided on the outer periphery.
Is provided so that the relative rotation phase between the camshaft 1A and the cam pulley 12 can be changed to change the valve timing of the exhaust valve.

The cam pulley 12 is generally cylindrical.
The outer peripheral portion is formed on a gear portion 12a on which a timing belt (not shown) is hung, and the end of the camshaft 1A is inserted through the inner peripheral center of the boss portion 12b. A flange-shaped end plate 13 is fixed to a front end of the cam pulley 12, and a center portion of the end plate 13 is formed in a central cylindrical portion 13a extending in the axial direction.

On the other hand, the valve timing changing mechanism 10A is disposed on the outer periphery of the end of the camshaft 1A, and a hub 21 (described later) of the valve timing changing mechanism 10A is narrowed in front of the camshaft 1A. An inner race 17 is provided, and the inner race 17 is attached by a camshaft bolt 18 which is fastened to the camshaft 1A from the end through the center thereof. A central cylindrical portion 13 a of the end plate 13 is rotatably supported on the outer periphery of the inner race 17 via a needle bearing 14. Note that a bearing cap 15 is attached to the tip.

The valve timing changing mechanism 10A described above is of an electromagnetically operated type. To explain the structure, the hub 21 clamped at the tip of the camshaft 1A is a disk 21a.
And engaging pieces 21b formed obliquely rearward in the axial direction at a plurality of locations around the circumference. Also, the boss 1 of the cam pulley 12
A vertical groove 12c is formed on the inner peripheral surface of the inner groove 2b.
A ring-shaped advancing plate 22 is engaged so as to be movable in the axial direction along the axis, and an inner periphery of the advancing plate 22 is screwed with a screw portion 23a on an outer periphery of the drum 23 (phase changing member). The drum 23 is moved in the axial direction by the relative rotation. Further, in the outer peripheral portion of the advancing plate 22, a concave portion 22b formed between the engaging protrusion 22a and the vertical groove 12c engages with the engaging piece 21b of the hub, and the engaging portion according to the axial movement. The rotation phase (valve timing) is changed by relatively rotating the hub 21, that is, the camshaft 1A, by changing the engagement position with the piece 21b.

The driving mechanism is provided inside the drum 23,
An electromagnetic coil 24 is provided (outside the camshaft 1A). The electromagnetic coil 24 has a bracket 2
5 is fixed, and the bracket 25 is fixed to the cylinder head side by an engaging structure (not shown) to prevent rotation. The electric cord 28 connected to the electromagnetic coil 24 is led out and connected to a power supply in accordance with the operation of the engine control unit 3 for controlling the drive.

Then, by energizing the electromagnetic coil 24, the electromagnetic coil 24 as a driving member is pressed against a drum 23 as a phase changing member, and a frictional resistance is given to the rotation of the drum 23 so that the drum 23 is rotated. The rotation angle of the drum 23 is limited by the stop plate 26, and the variable phase angle is adjusted. When the drive signal is off, the drum 23
Is returned and rotated in the retard direction by the spiral spring 27.

The valve timing changing mechanism 1 as described above
As the control for changing the valve timing of the exhaust valve and the intake valve by the operation of 0A and 10B, for example, FIG.
This is performed based on a control map as shown in FIG. This control map includes an engine speed Ne and a load Ce (= Qa / N
According to e), the respective valve timing changing mechanisms 1 correspond to the low load low rotation idle region to the high rotation region.
The operation states of 0A and 10B are set. In the figure, EX advance operates the opening / closing timing of the exhaust valve to the advanced side, and EX retard operates to the retard side. Similarly, IN advance advances the opening / closing timing of the intake valve to the advanced side and IN retard. The angle operates on the retard side. The engine control unit 3 determines the operating region and, corresponding to the operating region, the exhaust-side and intake-side valve timing changing mechanisms 10.
A drive signal is output to A and 10B to change and control the valve timing to obtain the combustion characteristics of the engine according to the respective operating conditions, thereby ensuring output performance and emission performance.

Next, the crank angle sensor 2 detects T every 90 degrees of rotation of the camshaft (every 180 degrees of crank angle).
This relationship is established when the exhaust-side valve timing changing mechanism 10A is not operated and the exhaust valve is on the retard side valve timing, and the relationship is established every 180 ° of the crankshaft. Although the TOP signal is output, when the exhaust-side valve timing changing mechanism 10A is operated and the camshaft 1A is driven to rotate by 5 °, the valve timing of the exhaust valve is changed to a 10 ° advance in crank angle. From the crank angle sensor 2
The signal is output at a timing 10 ° earlier by the crank angle than at the time of the retard. On the other hand, the required ignition timing changes according to the change of the valve timing. For example, the required ignition timing is 19 ° before the top dead center in the retarded state, but is 23 ° before the top dead center in the advanced state. The ignition signal is output after a lapse of a predetermined time obtained from the amount of advance from the input of the TOP signal to execute ignition.
The fluctuation of the TOP signal in accordance with the change of the valve timing is corrected by the correction means 6.

At this time, the valve timing changing mechanism 10A
It takes, for example, 0.3 seconds to actually rotate the camshaft 1A to change the valve timing by a predetermined amount after the drive signal (ON signal) is output. The valve timing gradually changes during the time, and if the TOP signal is corrected by the correction means 6 so as to be delayed by 10 ° of the crank angle simultaneously with the output of the ON signal, the ignition timing and the like based on this are actually Even if the valve timing is not changed, the advanced angle is controlled to be larger than required, and the combustion performance is reduced. In the following embodiment, the TOP signal is corrected gradually in accordance with the operation time of the valve timing. In addition, the length of the operation time is actually measured, and an error from a set value is learned and corrected.

In addition, when the ON signal is output to the valve timing changing mechanism 10, the operating time is calculated based on the learning correction value and the set value. Since the operation time differs depending on the off-rotation direction and the like, the operation time is obtained by simultaneously performing the correction according to the voltage, the rotation speed, and the like, and the correction is gradually performed over time corresponding to the length.

That is, as shown in the time chart of FIG. 5, at a point a where an ON signal is output to advance the valve timing, an operation time T until the change of the valve timing is completed is calculated, and a predetermined period is calculated. The correction amount is gradually increased by ΔDT every ΔT, and a correction of 10 ° is performed so that the TOP signal is input at a predetermined timing with respect to the crank angle at the point b when the operating time has elapsed, and the ignition timing is changed to the valve timing. The control for changing to the later characteristic value is performed.

The processing of the correction means 6 will be described with reference to the flowchart of FIG. First, after the control is started, in step S1, various signals such as a VCP signal of an operation detection sensor 7 for detecting an operation state of the valve timing changing mechanism 10, an engine speed signal Ne, an intake air amount signal Qa, and a battery voltage signal VB are input. . Then, it is determined from these signals based on the control map of FIG. 6 whether or not the operating state has approached the valve timing switching region.

When approaching the valve timing switching area, the calculation of the operation time T in step S3 is started. The calculation of the operation time T is based on a standard time S after learning described later,
The calculation is performed by multiplying a voltage correction coefficient V corresponding to the battery voltage VB by a rotation correction coefficient R corresponding to the engine speed Ne. The voltage correction coefficient V and the rotation correction coefficient R are obtained based on characteristics set in advance according to the battery voltage VB and the engine speed Ne. The voltage correction coefficient V is set so that T becomes longer, and the rotation correction coefficient R increases the inertia of the valve timing changing mechanism 10 as the engine speed increases, thereby affecting the operation time. Is set according to the change direction of the engine speed and the magnitude of the engine speed Ne.

Subsequently, in step S4, the switching change amount ΔDT
Is calculated. The switching change amount ΔDT is used to obtain a unit of the correction amount that is gradually changed during the operation time of FIG. 5 (one-step correction amount). Because the amount is changed, TOP
This is obtained by dividing the entire correction amount D (10 ° in the above example) of the signal by the number of corrections T / ΔT.

Then, in step S5, it is determined whether or not the switching signal of the operating state of the valve timing changing mechanism 10, which has been processed in a separate routine, has been output.
When the switching operation of the valve timing is started in S, in step S6, the TOP signal is corrected by the switching change amount ΔDT for every predetermined time leap ΔT during the operation time T from the start of the switching, and gradually. Perform the correction.

Further, in accordance with the operation of changing the valve timing, learning correction of the standard time S is performed in steps S7 to S9. In the learning correction, first, in step S7, the operation time Tm actually required for changing the phase of the camshaft 1 is measured based on the VCP signal of the operation detection sensor 7, and in step S8, the actually measured operation time Tm is measured by the voltage. The actual measurement standard time Sm is calculated by dividing by the correction coefficient V and the rotation correction coefficient R. Then, in step S9, the actual measurement standard time Sm
Is reflected in the standard time S to perform learning correction. For example, a difference Sm-S between the two is multiplied by a predetermined reflection coefficient K and added.

According to the above-described embodiment, the change in the phase of the camshaft 1 caused by the operation of the valve timing changing mechanism 10 causes a change in the detected phase of the TOP signal of the crank angle sensor. By doing so, a pseudo TOP signal is input to the engine control unit 3 at a predetermined crank angle, and the ignition timing and the fuel injection control can be executed with desired characteristics. Also, the TOP
By performing the correction of the signal gradually in accordance with the changing speed of the valve timing, it is possible to prevent the occurrence of a shift such as the ignition timing control at the beginning of the operation and to perform the accurate correction.

Further, the operating time required for changing the valve timing is learned and corrected by measuring the actual operating time, and is corrected in accordance with the battery voltage and the engine speed so as to increase the correction accuracy, thereby increasing the valve timing. It compensates for manufacturing errors of the change mechanism, aging, and the like.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of an engine crank angle sensor output correction device according to an embodiment of the present invention .

FIG. 2 is a schematic plan view of a cylinder head portion of one bank of a V-type engine showing an arrangement example of a halve timing changing mechanism and a crank angle sensor .

FIG. 3 is a sectional view showing a structural example of a valve timing changing mechanism .

FIG. 4 is a flowchart for explaining processing of a correction unit .

FIG. 5 is a time chart showing a correction characteristic when a valve timing is changed .

[6] control map view showing an operating state of the exhaust side and the intake side valve timing mechanism corresponding to the operating area
You.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camshaft 2 Crank angle sensor 3 Engine control unit 6 Correction means 7 Operation detection sensor 10 Valve timing change mechanism 12 Cam pulley 24 Electromagnetic coil

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Akira Tanaka 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (56) References JP-A-59-93965 (JP, A) JP-A Sho 61-201868 (JP, A) JP-A-63-71549 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 13/02 F02D 41/00-45/00 395

Claims (3)

(57) [Claims] 1. An engine including a crank angle sensor for detecting a phase of a camshaft and a valve timing changing mechanism for changing a valve timing by changing a phase of the camshaft. a correction means for correcting the crank angle sensor output in accordance with the phase change of the shaft, the correction of the crank angle sensor output by the correcting means, Ba
Of the actual valve timing from the start of the
Perform gradually according to the operation time until the end of switching
An engine crank angle sensor output correction device characterized by being configured . 2. A correction of the crank angle sensor output by the correction means also performs a learning correction for correcting a difference between the set value by measuring the operation time until the switching end of the valve timing
2. The device for correcting the output of a crank angle sensor of an engine according to claim 1, wherein: 3. A correction of the crank angle sensor output by said correcting means, intended to measure the battery voltage during operation of the valve timing change mechanism is performed by modifying the operation setting time until the switching completion in response to the voltage a crank angle sensor output correcting device for an engine according to claim 1, wherein there.