JP5611309B2 - Phase control device and phase control method for variable valve timing device - Google Patents

Description

  The present invention relates to a phase control device of a valve timing adjusting device for adjusting the opening / closing timing of one or both of an intake valve and an exhaust valve in accordance with the operating state of an engine.

  In recent years, internal combustion engines mounted on vehicles often employ variable valve timing devices that vary the valve timing of intake valves and exhaust valves for the purpose of improving fuel consumption and reducing exhaust emissions. Currently, many variable valve timing devices change the valve timing of intake and exhaust valves that are driven to open and close by the camshaft by changing the camshaft phase angle (the rotational phase of the camshaft relative to the crankshaft). .

  In order to change the valve timing, it is necessary to detect the camshaft phase angle (rotation phase of the camshaft with respect to the crankshaft). As a detection method, the time difference between the crank angle signal input and the cam angle signal input and the latest crank angle signal input are required. There is a method of obtaining the crank angle from the cycle. The camshaft phase angle must be detected in the entire engine speed range in order to detect a failure state such as actuator sticking. However, when the engine is in the low rotation range, the rotation fluctuation becomes large, and there is a case where the engine rotates in the reverse direction just before the engine is stopped. If it is calculated from the crank angle signal and the cam angle signal, an erroneous cam shaft phase angle is detected. there's a possibility that.

  As a means for detecting the cam shaft phase angle even in the low rotation region, in the variable valve timing control device for an internal combustion engine described in Patent Document 1 below, a section (crank for detecting the cam shaft phase angle in the low rotation region). It has been proposed to detect the camshaft phase angle by reducing the angle).

JP 2006-112385 A

  However, when reverse rotation of the engine occurs, the crank angle can be correctly detected even using the method of Patent Document 1 in which the above-described cam shaft phase angle detection (crank angle) is detected with a small interval. Since this is not possible, an incorrect camshaft phase angle is detected. By detecting an incorrect cam shaft phase angle, there is a problem that control based on the cam shaft phase angle does not operate as designed.

  The present invention has been made to solve the above-described problems. The camshaft phase angle advancement cannot be temporarily calculated in a low rotation region where the rotation fluctuation of the internal combustion engine becomes large and the internal combustion engine rotates backward. If the cam is fixed on the advance side when the cam is on the intake side, and the retard side when the cam is on the exhaust side, the correct amount of advance or retard can be calculated. An object of the present invention is to provide a phase control device for a variable valve timing device.

The present invention relates to a phase control device for a variable valve timing device that controls a valve timing changing mechanism of a variable valve timing device for an internal combustion engine to change a valve overlap amount by changing a valve timing of at least one of an intake valve and an exhaust valve. A crank angle position detection unit for detecting a crank angle position of the internal combustion engine, a cam angle position detection unit for detecting a cam angle position of the internal combustion engine, and a rotation result of the internal combustion engine based on a detection result of the crank angle position detection unit. A camshaft phase for controlling the valve timing changing mechanism from the crank angle position and the cam angle position detected by the crank angle position detector and the cam angle position detector. A camshaft phase angle calculation unit for calculating an angle, and when the rotational speed of the internal combustion engine is equal to or less than a predetermined threshold value, The advance side with respect to the previous camshaft phase angle when the cam shaft phase angle calculated by the serial camshaft phase angle calculating section of the intake side, retard relative previous camshaft phase angle when the exhaust side And a cam shaft phase angle control unit that performs update restriction on the calculated cam shaft phase angle when it appears on the side of the variable valve timing device.

  In this invention, the rotational fluctuation of the internal combustion engine becomes large, and in the low rotation region where the internal combustion engine rotates backward, the advance amount and the retard amount of the cam shaft phase angle that cannot be temporarily temporarily calculated are limited, When the cam is fixed to the advance side when the cam is on the intake side, and when the cam is fixed to the retard side, the phase control device for the variable valve timing device that can calculate the correct advance amount and retard amount can be provided. .

1 is a schematic configuration diagram of a control system for an internal combustion engine provided with a valve timing changing mechanism including a phase control device of a variable valve timing device according to an embodiment of the present invention. It is a time chart for demonstrating control operation | movement of the phase control apparatus of the variable valve timing apparatus by this invention. It is an operation | movement flowchart which shows an example of the process sequence in the phase control apparatus of the variable valve timing apparatus by this invention. It is an operation | movement flowchart which shows another example of the process sequence in the phase control apparatus of the variable valve timing apparatus by this invention. 6 is a time chart for explaining a method of calculating a camshaft phase angle (a rotational phase of a camshaft with respect to a crankshaft).

  First, a general method for calculating the camshaft phase angle will be briefly described with reference to FIG. Note that FIG. 5 is an explanation of the intake side, but the exhaust side may be considered opposite to the intake side, and the advance angle and the retard angle may be exchanged. θT represents the phase angle (rotation angle) with respect to the reference angle of the first crank angle signal [degCA] after the phase detection cam signal is input. θA represents the phase angle (rotation angle) between the crank angle signals [degCA]. T indicates the time between the crank angle signals sandwiching the phase detection cam signal. t represents the time between the phase detection cam signal and the first crank angle signal after the phase detection cam signal is input. Using the value, the camshaft phase angle is detected from the following equation (1).

    Cam shaft phase angle = θT− (θA × t / T) (1)

  As shown in the above equation (1), the time T between the crank angle signals sandwiching the phase detection cam signal and the time between the phase detection cam signal and the first crank angle signal after the phase detection cam signal is input. The camshaft phase angle is detected by converting the crank angle from t.

  However, as described above, when reverse rotation of the engine occurs, even if the section (crank angle) for detecting the conventional camshaft phase angle is reduced and detected, the angle between the cranks cannot be detected correctly. The camshaft phase angle is detected.

  In the present invention, in order to solve the above-described problem, in a low speed region where the engine rotates in reverse, the hydraulic pressure that is operated to the advance side (the retard side in the case of the exhaust side, the same applies hereinafter) on the intake side. Since it cannot be secured, the camshaft phase angle does not move toward the advance side. Therefore, if the camshaft phase angle calculation value is updated to the advance side in a region where the hydraulic pressure for operating the hydraulic actuator cannot be secured, the camshaft phase angle is likely not calculated correctly. By delaying the update of the camshaft phase angle to the advance side or by setting an upper limit for the update to the advance side, the state is close to the actual camshaft phase angle, and the above problem is solved.

  Hereinafter, a phase control device and the like of a variable valve timing device according to the present invention will be described with reference to the drawings according to each embodiment. In each embodiment, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. For convenience of explanation, the case of the intake side will be described below, but the present invention is applied to both the intake side and the exhaust side, and on the exhaust side, the advance angle in the explanation of the intake side is set to be retarded. It can be realized by replacement.

Embodiment 1 FIG.
FIG. 1 shows a schematic configuration of a control system for an internal combustion engine having a valve timing changing mechanism including a phase control device for a variable valve timing device according to an embodiment of the present invention. In each cylinder 100 (only one cylinder is shown), a combustion chamber 100a is formed by a piston 101 that reciprocates inside thereof, and a spark plug 102 is provided in a cylinder head above the combustion chamber 100a. The front end faces the combustion chamber 100a. Each cylinder 100 is connected to an intake pipe 103 that guides intake air to the combustion chamber 100a and an exhaust pipe 104 for exhausting combustion gas from the combustion chamber 100a. An intake valve 117 is provided at the intake port where the intake pipe 103 opens to the combustion chamber 100a, and an exhaust valve 118 is provided at the exhaust port where the exhaust pipe 104 opens to the combustion chamber 100a.

  A throttle valve 108 for controlling the amount of intake air supplied to the combustion chamber 100a is provided in the intake pipe 103, and the opening degree of the throttle valve 108 is detected in the vicinity of the throttle opening degree attached to the intake pipe 103. Detected by sensor 112. Further, in the intake pipe 103, a fuel injection valve 105 for supplying fuel to the intake pipe 103 and a pressure sensor 113 for detecting the pressure in the intake pipe 103 are provided on the downstream side of the throttle valve 108. It has been. Further, the cylinder 100 is provided with a water temperature sensor 107 for detecting the temperature of the engine cooling water, and the exhaust pipe 104 is provided with an oxygen sensor 106 for detecting the oxygen concentration in the exhaust gas.

  Above the intake valve 117 and the exhaust valve 118, an intake camshaft 115 provided with a cam 115b for driving the valves to open and close and an exhaust camshaft 119 provided with a cam 119b are arranged. 115 and the exhaust camshaft 119 are attached with an intake side timing pulley 120 and an exhaust side timing pulley 119a. The intake side timing pulley 120 and the exhaust side timing pulley 119a are operatively connected to a crankshaft 116 connected to the piston 101 in each cylinder 100 via a piston rod 116a via a timing belt (not shown). The intake camshaft 115 and the exhaust camshaft 119 are rotationally driven in synchronization with the rotation of the crankshaft 116.

  A hydraulic actuator (VVT ACT) 114 driven by the lubricating oil of the internal combustion engine is connected to the end face of the intake camshaft 115, and the hydraulic actuator 114 changes the valve opening / closing timing of the intake valve 117. That is, the hydraulic actuator 114 continuously changes the valve opening / closing timing of the intake valve 117 by changing the displacement angle of the intake camshaft 115 with respect to the intake side timing pulley 120. The cam angle position detection sensor 111 detects the cam angle position of the intake camshaft 115.

  An oil control valve (OCV) 121 supplies hydraulic oil to the hydraulic actuator 114, adjusts the amount of hydraulic oil, and drives the hydraulic actuator 114 to change the opening / closing timing of the intake valve 117. As described above, FIG. 1 shows a system that changes only the valve timing on the intake side, but a system that changes the valve timing on the exhaust side is configured similarly.

  The crankshaft 116 is fixedly attached with a rotating plate 116b having irregularities on the outer periphery, and a crank angle position detection sensor 110 disposed so as to be close to the rotating plate 116b and face the outer peripheral portion thereof. By detecting irregularities on the outer periphery of 116b, the rotational position (crank angle position) of the crankshaft 116 and the rotational speed of the internal combustion engine (hereinafter referred to as engine rotational speed) are detected. The output signals of various sensors such as a crank angle position detection sensor 110, a throttle opening degree detection sensor 112, a pressure sensor 113, an intake air amount detection sensor (not shown), an oxygen sensor 106, a water temperature sensor 107, etc. The ECU 122 detects the operating state of the internal combustion engine from the information, and the ignition plug 102, the fuel injection valve 105, and the oil control valve 121 are detected in accordance with the detected operating state of the internal combustion engine. Control etc.

  FIG. 2 is a time chart for explaining the control operation of the phase control device of the variable valve timing device according to the present invention. Here, FIG. 2 is a view showing the intake side. Since only the advance angle and retard angle are reversed on the exhaust side, the description is omitted. T201 of (a) has shown the time-dependent change of engine speed (internal combustion engine speed). T202 in (b) indicates a change with time of the cam shaft phase angle calculated according to the cam shaft phase angle detection method in accordance with the engine speed indicated by T201. The calculation of the camshaft phase angle is continued even when the rotational speed is in a low rotational range (there is a case where the hydraulic actuator 114 rotates in reverse).

  However, as indicated by T203, there is a case where the engine rotates reversely before stopping, and when the camshaft phase angle is calculated by the above equation (1), the calculation result on the advance side is obtained because it cannot be calculated correctly. . Therefore, when the calculation result to the advance side (in the intake side) is calculated in the low rotation region as in T203, there is a high possibility that the calculation result is not correct, and in the low rotation region, the camshaft phase angle is Since the engine does not operate on the advance side, a predetermined threshold speed of the engine is provided as shown in T204, and if the engine speed is equal to or less than the threshold speed T204, the camshaft phase angle should be detected on the advance side. For example, when updating the camshaft phase angle, a filter is applied to delay the update (see T205). The update amount of the camshaft phase angle can be limited by delaying the advance side update. Further, the cam shaft phase angle update amount may be limited by providing an upper limit to the phase update amount. As described above, the camshaft phase angle can be updated at an angle close to the actual phase angle by limiting the update amount of the camshaft phase angle.

  FIG. 3 is an example of an operation flowchart of the phase control device of the variable valve timing device according to the present invention. This control operation is performed by the ECU 122. FIG. 3 illustrates the intake side, but the exhaust side can be realized by replacing the advance angle in the description of the intake side with a retard angle. This operation indicates processing for each predetermined crank angle position (for example, BTDC 75 ° CA).

First, in step S301, the crank angle position detection sensor 110 detects a crank angle position detection signal SGT. That is, the crank angle position detection signal SGT from the crank angle position detection sensor 110 is input to obtain the crank angle position.
Next, in step S302, the cam angle position detection sensor 111 detects the cam angle position detection signal SGC. That is, the cam angle position detection signal SGC from the cam angle position detection sensor 111 is input to obtain the cam angle position.
Next, in step S303, the engine speed Ne is calculated from the crank angle position detection signal SGT detected in step S301.

  Next, in step S304, a cam shaft phase angle for controlling the oil control valve 121 of the valve timing changing mechanism is calculated from the detected crank angle position and cam angle position according to the above equation (1).

Next, in step S305, it is determined whether the engine speed Ne calculated in step S303 is equal to or less than a determination value N1. The determination value N1 is a predetermined engine speed that is in a low rotation range where the hydraulic pressure for operating the hydraulic actuator 114 cannot be secured. If it is determined that the engine speed Ne is equal to or less than the determination value N1, the process proceeds to step S306.
In step S306, it is determined whether or not the calculated camshaft phase angle appears on the advance side. If the camshaft phase angle appears on the advance side, the process proceeds to step S307.

  In step S307, a filter is applied according to the following equation (2).

    (Previous) Cam shaft phase angle x coefficient K + (Current) Cam shaft phase angle x (1-coefficient K) (2)

  Formula (2) is a filter calculation formula having a coefficient K (0 ≦ K ≦ 1). It is a general filter calculation formula that determines whether to focus on the previous cam shaft phase angle or the current cam shaft phase angle by changing the coefficient K in the range of 0 to 1 . In step S307, the cam shaft phase angle detected this time is likely not to be calculated correctly. Therefore, the coefficient K is set to a value close to 1 to delay the reflection of the cam shaft phase angle detected this time. The coefficient K is changed, for example, according to the engine speed (larger as the engine speed is lower).

On the other hand, if the camshaft phase angle does not appear on the advance side in step S306, the process proceeds to step S308.
In step S308, 0 is set to the coefficient K in equation (2). Setting the coefficient K to 0 means that there is no filter, and that the previous cam shaft phase angle value is not used for updating the cam shaft phase angle.

If it is determined in step S305 that the engine speed is greater than the determination value N1, the process proceeds to step S309.
In step S309, the coefficient K is set to 0 as in the description of step S308.
Then, using the filter coefficient set in steps S307 to S309, the camshaft phase angle is updated in step S310. The oil control valve 121 is controlled in accordance with the updated camshaft phase angle.

  FIG. 4 is another example of an operation flowchart of the phase control device of the variable valve timing device according to the present invention. This control operation is performed by the ECU 122. Similar to FIG. 3, FIG. 4 is a description of the intake side, but the exhaust side can be realized by replacing the advance angle in the description of the intake side with a retard angle. This operation also indicates processing for each predetermined crank angle position (for example, BTDC 75 ° CA).

  The processing from step S401 to S405 is the same as the processing from step S301 to S305 in FIG.

In step S406, it is determined whether or not the calculated camshaft phase angle appears on the advance side. If the camshaft phase angle appears on the advance side, the process proceeds to step S407.
In step S407, the calculated cam shaft phase angle is compared with a preset upper limit value K1, and the smaller one is set as the current cam shaft phase angle. The upper limit value K1 is set to an angle close to the actual cam shaft phase angle.
On the other hand, if the cam shaft phase angle does not appear on the advance side in step S406, the detected value is set as the current cam shaft phase angle.

Even when it is determined in step S405 that the engine speed is greater than the determination value N1, the detected value is set as the current cam shaft phase angle.
The oil control valve 121 is controlled in accordance with the updated camshaft phase angle.

The hydraulic actuator 114, intake camshaft 115, cam 115b, intake valve 117, exhaust valve 118, exhaust camshaft 119, exhaust side timing pulley 119a, cam 119b, intake side timing pulley 120, and oil control valve 121 are variable. Configure the valve timing device,
The hydraulic actuator 114 and the oil control valve 121 constitute a valve timing changing mechanism (114, 121),
ECU 122, crank angle position detection sensor 110, cam angle position detection sensor 111, etc. constitute a phase control device,
Steps S301 and S401 in the crank angle position detection sensor 110 and ECU 122 constitute a crank angle position detection unit,
Steps S302 and S402 in the cam angle position detection sensor 111 and ECU 122 constitute a cam angle position detection unit,
Steps S303 and S403 in the ECU 122 constitute an internal combustion engine speed calculation unit,
Steps S304 and S404 in the ECU 122 constitute a camshaft phase angle calculation unit,
Steps S305-S310 and S405-S407 in the ECU 122 constitute a camshaft phase angle control unit.

  According to the present embodiment described in detail above, in the detection of the camshaft phase angle, if the camshaft phase angle cannot be calculated correctly temporarily in the low speed range where the engine may reversely rotate, the engine proceeds. Variable valve timing that limits the amount of retard if it is on the angle or exhaust side, and can detect the correct amount of advance (retard) if the cam is stuck to the advance (retard) side An apparatus phase control device or the like can be obtained.

  100 cylinder, 100a combustion chamber, 101 piston, 102 spark plug, 103 intake pipe, 104 exhaust pipe, 105 fuel injection valve, 106 oxygen sensor, 107 water temperature sensor, 108 throttle valve, 110 crank angle position detection sensor, 111 cam angle position Detection sensor, 112 Throttle opening detection sensor, 113 Pressure sensor, 114 Hydraulic actuator, 115 Intake camshaft, 115b Cam, 116 Crankshaft, 116a Piston rod, 116b Rotating plate, 117 Intake valve, 118 Exhaust valve, 119 Exhaust camshaft 119a Exhaust side timing pulley, 119b Cam, 120 Intake side timing pulley, 121 Oil control valve, 122 ECU.

Claims (4)

A phase control device for a variable valve timing device that controls a valve timing changing mechanism of a variable valve timing device of an internal combustion engine to change a valve overlap amount by changing a valve timing of at least one of an intake valve and an exhaust valve,
A crank angle position detector for detecting a crank angle position of the internal combustion engine;
A cam angle position detector for detecting the cam angle position of the internal combustion engine;
An internal combustion engine speed calculator that calculates the rotational speed of the internal combustion engine from the detection result of the crank angle position detector;
A cam shaft phase angle calculation unit for calculating a cam shaft phase angle for controlling the valve timing changing mechanism from the crank angle position and the cam angle position detected by the crank angle position detection unit and the cam angle position detection unit;
When the rotational speed of the internal combustion engine is equal to or less than a predetermined threshold value, when the cam shaft phase angle calculated by the cam shaft phase angle calculation unit is on the intake side, the advance side and the exhaust side are compared with the previous cam shaft phase angle . A camshaft phase angle control unit that performs update restriction on the calculated camshaft phase angle when it appears on the retarded side with respect to the previous camshaft phase angle .
A phase control device for a variable valve timing device, comprising:   The cam shaft phase angle control unit performs a first-order lag filter process using a filter coefficient that is changed according to the internal combustion engine speed, on the cam shaft phase angle calculated by the cam shaft phase angle calculation unit. The phase control device for a variable valve timing device according to claim 1, wherein the phase angle is updated.   2. The variable according to claim 1, wherein the cam shaft phase angle control unit updates the cam shaft phase angle calculated by the cam shaft phase angle calculation unit according to an internal combustion engine speed with an upper limit. Phase control device for valve timing device. A phase control method of a variable valve timing device that controls a valve timing changing mechanism of a variable valve timing device of an internal combustion engine to change a valve overlap amount by changing a valve timing of at least one of an intake valve and an exhaust valve,
Detecting the crank angle position of the internal combustion engine;
Detecting the cam angle position of the internal combustion engine;
Calculating the rotational speed of the internal combustion engine from the detected crank angle position;
Calculating a camshaft phase angle for controlling the valve timing changing mechanism from the detected crank angle position and cam angle position;
When the rotational speed of the internal combustion engine is below a predetermined threshold value, the advance-side cam shaft phase angle is calculated relative to the previous camshaft phase angle when the intake valve side, the last camshaft when the exhaust valve side A step of performing update restriction on the calculated camshaft phase angle when it appears on the retard side with respect to the phase angle ;
A phase control method for a variable valve timing device.

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