JP2018066331A - Control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device capable of calculating a VCT phase of higher accuracy even when a rotational frequency of an engine and a cam shaft phase to a crank shaft phase are changed after a cam angle signal is input.SOLUTION: An ECU 30 as a control device calculates a steady VCT phase as a VCT phase corresponding to a steady state when the steady state is determined, and executes a transient processing for adding a transient phase change amount of a cam shaft to a crank shaft to the steady VCT phase when a transient state is determined, to calculate a transient VCT phase corresponding to the transient state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an engine control device.

  There is known a variable valve timing device that optimizes the opening / closing timing of an intake valve that supplies air to an engine and an exhaust valve that discharges exhaust gas by continuously controlling a camshaft phase with respect to a crankshaft phase in the engine. The variable valve timing device continuously controls the camshaft phase according to the operating state such as the engine speed and the accelerator opening so that an appropriate torque and output of the engine can be obtained. Therefore, it is necessary to detect the current cam shaft phase and feedback control the difference from the target cam shaft phase.

  In the variable valve timing device, a crank angle sensor for detecting the crankshaft phase and a cam angle sensor for detecting the camshaft phase are provided. The crank angle sensor detects signal teeth of a crankshaft timing rotor attached to the crankshaft. Since the signal teeth of the crankshaft timing rotor are provided, for example, every 10 degrees, the crank angle signal is output from the crank angle sensor every 10 [degCA] which is a predetermined crank angle.

  The cam angle sensor detects the signal teeth of the camshaft timing rotor attached to the camshaft. Since the cam angle sensor is used for cylinder discrimination in conjunction with detection of the cam shaft phase, the number of signal teeth of the cam shaft timing rotor is small, and there may be 1 to 4 signal teeth. In the case of a 4-stroke / 1-cycle engine, four steps of suction, compression, combustion, and exhaust are executed during one cycle, so the crankshaft rotates twice and the camshaft rotates once. Therefore, when the number of signal teeth of the camshaft timing rotor is one, a cam angle signal is output from the cam angle sensor every 720 [degCA] which is a predetermined cam angle.

  The phase of the cam shaft can be expressed by, for example, a VCT (Variable Cam Timing) phase that is a crank angle difference between the phase calculation timing and the cam angle signal. In this case, a method of calculating the VCT phase based on, for example, a time difference between the cam angle signal output timing and the crank angle signal output timing is known. This calculation method will be described with reference to FIG. 11A shows the cam angle signal, and FIG. 11B shows the crank angle signal.

As shown in FIG. 11, the crank angle difference between the phase calculation timing and the cam angle signal input timing is defined as VCT phase [degCA], and the time from the cam angle signal input timing to the crank angle signal input timing corresponding to the phase calculation timing. Is Tvct [s], the VCT phase [degCA] is expressed by the following equation (f01). T30 [s] is a time corresponding to a crank angle of 30 [degCA].
VCT phase [degCA] = Tvct [s] / T30 [s] × 30 [degCA]. . . (F01)

  If the engine speed does not fluctuate, the input interval of the crank angle signal does not fluctuate, so that no error occurs even if the VCT phase is calculated by the above calculation method. Similarly, if the cam angle phase relative to the crankshaft phase does not change, the relationship between the cam angle signal input timing and the crank angle signal input timing is also kept constant. Does not occur.

  In the variable valve timing apparatus described in Patent Document 1 below, the VCT phase is calculated by the same method as this, and the difference between the rotational speed of the motor and the rotational speed of the camshaft that causes the camshaft phase to vary in the variable valve timing apparatus. Correction based on

Japanese Patent Laid-Open No. 2004-162706

  When the engine speed fluctuates, the conventional VCT phase calculation method cannot accurately calculate the VCT phase. This point will be described with reference to FIG. FIG. 12A shows the cam angle signal. FIG. 12B shows a crank angle signal when the engine speed is constant. FIG. 12C shows the crank angle signal when the engine speed increases. (D) in FIG. 12 shows a crank angle signal when the engine speed decreases.

  As shown in FIGS. 12A and 12B, if the engine speed is constant, the time corresponding to the crank angle 30 [degCA] is constant, and the cam angle signal input timing is changed to the phase calculation timing. Since the time Tvct1 [s] until the corresponding crank angle signal input timing is also constant, the VCT phase can be correctly calculated by the above equation (f01).

  As shown in FIG. 12C, when the engine speed increases after the cam angle signal input timing, the time corresponding to the crank angle [30 deg CA] is shortened, and the cam angle signal input timing corresponds to the phase calculation timing. The time Tvct2 [s] until the crank angle signal input timing is shortened. In this case, even if the VCT phase is constant, since the engine speed has increased, the VCT phase calculated by the above formula (f01) becomes small, resulting in erroneous calculation.

  As shown in FIG. 12D, when the engine speed decreases after the cam angle signal input timing, the time corresponding to the crank angle [30 deg CA] becomes longer, corresponding to the phase calculation timing from the cam angle signal input timing. The time Tvct3 [s] until the crank angle signal input timing is increased. In this case, even if the VCT phase is constant, since the engine speed is decreasing, the VCT phase calculated by the above formula (f01) becomes large, resulting in erroneous calculation.

  On the other hand, even when the engine speed is constant and the camshaft phase fluctuates, the conventional VCT phase calculation method cannot accurately calculate the VCT phase. This point will be described with reference to FIG. FIG. 13A shows the crank angle signal. FIG. 13B shows the cam angle signal and the cam shaft phase when the cam shaft phase is constant. In FIG. 13C, the cam angle signal when the cam shaft phase is advanced is indicated by a broken line, and the cam shaft phase is indicated by a solid line. In FIG. 13D, the cam angle signal when the cam shaft phase is retarded is indicated by a broken line, and the cam shaft phase is indicated by a solid line.

  As shown in FIGS. 13A and 13B, if the cam angle phase is constant, the VCT phase does not change after the cam angle signal is input. Therefore, the VCT phase is expressed as VCT1 according to the above equation (f01). [DegCA] can be calculated correctly.

  As shown in FIG. 13C, when the cam angle phase is advanced after the cam angle signal is input, the VCT phase is erroneously calculated to increase. The time Tvct1 [s] from the cam angle signal input timing to the crank angle signal input timing corresponding to the phase calculation timing does not change, and the calculated VCT phase is VCT1 [degCA], but the actual VCT phase is more than that. This is because it is a small VCT2 [degCA].

  As shown in FIG. 13D, when the cam angle phase is delayed after the cam angle signal is input, the VCT phase is erroneously calculated to be smaller. The time Tvct1 [s] from the cam angle signal input timing to the crank angle signal input timing corresponding to the phase calculation timing does not change, and the calculated VCT phase is VCT1 [degCA], but the actual VCT phase is more than that. This is because it is a large VCT3 [degCA].

  As described above, an error occurs in the VCT phase calculated by the above formula (f01) under the situation where the engine speed fluctuates or the camshaft phase fluctuates. In the conventional technology, correction is performed based on the difference between the rotational speed of the motor that changes the camshaft phase and the rotational speed of the camshaft in the variable valve timing device. Since the error is not corrected, the error cannot be eliminated.

  The present disclosure is an engine control device that calculates a more accurate VCT phase even when a camshaft phase changes with respect to an engine speed or a crankshaft phase after a cam angle signal is input. It is an object of the present invention to provide a control device capable of performing the above.

  The present disclosure is a control device for the engine (11), and includes a state determination unit (302) and a phase calculation unit (301). The state determination unit is an intake valve that is driven to open and close by the camshaft by changing the camshaft phase, which is the rotational phase of the camshaft (16) relative to the crankshaft (12) of the engine (11). And / or a change in camshaft phase in the variable valve timing device (18) that changes the valve timing of the exhaust valve, or a transient state in which at least one of the camshaft phase fluctuations occurs, or a fluctuation in the rotational speed of the engine is also a fluctuation in the camshaft phase. It is determined whether the steady state is not generated. The phase calculation unit includes a cam angle signal input every predetermined cam angle, a crank angle signal input every predetermined crank angle, and a rotation angle signal indicating a rotation angle of the motor (26) that changes the cam shaft phase. Based on, a VCT phase that is a crank angle difference between the phase calculation timing and the cam angle signal input timing is calculated. When the state determination unit determines that the state is in a steady state, the phase calculation unit calculates a steady VCT phase corresponding to the steady state by executing a steady process. When the state determination unit determines that the state is a transient state, the phase calculation unit performs a transient process for adding the transient phase change amount of the camshaft with respect to the crankshaft to the steady VCT phase, so that the transient corresponding to the transient state is obtained. Calculate the VCT phase.

  According to the present disclosure, in the case of a transient state in which the camshaft phase fluctuates, the transient process for adding the transient phase change amount to the steady VCT phase corresponding to the steady state is executed. The VCT phase can be calculated. Since the steady VCT phase is calculated in correspondence with the steady state, errors caused by fluctuations in engine speed and camshaft phase can be minimized. Since the amount of transient phase change of the camshaft with respect to the crankshaft in the transient state is added to the steady VCT phase with high accuracy in this way, the VCT phase with higher accuracy can be calculated.

  According to the present disclosure, there is provided a control device capable of calculating a VCT phase with higher accuracy even when a cam shaft phase is changed with respect to an engine speed or a crank shaft phase after a cam angle signal is input. Can be provided.

FIG. 1 is a diagram illustrating a configuration of an entire system using an ECU according to an embodiment. FIG. 2 is a diagram showing a configuration of the variable valve timing device shown in FIG. FIG. 3 is a flowchart for illustrating the operation of the ECU shown in FIG. FIG. 4 is a flowchart for illustrating the operation of the ECU shown in FIG. FIG. 5 is a flowchart for explaining the operation of the ECU shown in FIG. FIG. 6 is a flowchart for illustrating the operation of the ECU shown in FIG. FIG. 7 is a flowchart for explaining the operation of the ECU shown in FIG. FIG. 8 is a flowchart for explaining the operation of the ECU shown in FIG. FIG. 9 is a flowchart for explaining the operation of the ECU shown in FIG. FIG. 10 is a flowchart for illustrating the operation of the ECU shown in FIG. FIG. 11 is a diagram for explaining a VCT phase calculation method. FIG. 12 is a diagram for explaining the influence of engine speed fluctuation in the conventional VCT phase calculation method. FIG. 13 is a diagram for explaining the influence of the camshaft phase in the conventional VCT phase calculation method.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  As shown in FIG. 1, in the engine 11, the rotational power of the crankshaft 12 is transmitted to the sprockets 14 and 15 by the timing chain 13. Since the sprocket 14 is configured to rotate integrally with the intake side camshaft 16, the rotational power of the crankshaft 12 is transmitted to the intake side camshaft 16. Since the sprocket 15 is configured to rotate integrally with the exhaust side camshaft 17, the rotational power of the crankshaft 12 is transmitted to the exhaust side camshaft 17.

  A motor-driven variable valve timing device 18 is provided on the intake camshaft 16 side. With this variable valve timing device 18, the cam shaft phase that is the rotational phase of the intake side cam shaft 16 with respect to the crankshaft 12 can be varied. In the present embodiment, the valve timing of an intake valve (not shown) driven to open and close by the intake side camshaft 16 is varied by varying the camshaft phase.

  The present embodiment is configured as a VCT (Variable Cam Timing) mechanism capable of continuously varying the camshaft phase. This embodiment is configured as a VVT (Variable Valve Timing) mechanism in that the valve timing of the intake valve is varied by varying the camshaft phase. In this embodiment, an example in which the valve timing of the intake valve is made variable is used, but the valve timing of the exhaust valve may also be made variable.

  A cam angle sensor 19 that outputs a cam angle signal for each predetermined cam angle is attached to the outer peripheral side of the intake side cam shaft 16. The cam angle sensor 19 detects signal teeth of a cam shaft timing rotor (not shown) attached to the intake side cam shaft 16. The cam angle sensor 19 may be used for cylinder discrimination along with detection of the cam shaft phase, and the number of signal teeth of the cam shaft timing rotor is provided from 1 to 4. When the number of signal teeth of the camshaft timing rotor is one, a cam angle signal is output from the cam angle sensor 19 every 720 deg CA which is a predetermined cam angle. When the number of signal teeth of the camshaft timing rotor is two, the cam angle signal is output from the cam angle sensor 19 every 360 deg CA which is a predetermined cam angle. A cam angle signal output from the cam angle sensor 19 is input to an ECU (Electronic Control Unit) 30.

  A crank angle sensor 20 that outputs a crank angle signal for each predetermined crank angle is attached to the outer peripheral side of the crankshaft 12. The crank angle sensor 20 detects signal teeth of a crankshaft timing rotor (not shown) attached to the crankshaft 12. Since the signal teeth of the crankshaft timing rotor are provided, for example, every 10 degrees, the crank angle signal is output from the crank angle sensor 20 every 10 deg CA which is a predetermined crank angle. A crank angle signal output from the crank angle sensor 20 is input to the ECU 30.

  Next, the variable valve timing device 18 will be described with reference to FIG. The variable valve timing device 18 has a phase variable mechanism 21. The phase variable mechanism 21 includes an outer gear 22, an inner gear 23, and a planetary gear 24.

  The outer gear 22 is a gear with internal teeth arranged concentrically with the intake side camshaft 16. The inner gear 23 is a gear with external teeth arranged concentrically on the inner peripheral side of the outer gear 22. The planetary gear 24 is a gear that is disposed between the outer gear 22 and the inner gear 23 and meshes with both.

  The outer gear 22 is provided so as to rotate integrally with the sprocket 14 that rotates in synchronization with the crankshaft 12. The inner gear 23 is provided so as to rotate integrally with the intake side camshaft 16.

  The planetary gear 24 turns around the inner gear 23 in a circular orbit while being engaged with the outer gear 22 and the inner gear 23. The planetary gear 24 plays a role of transmitting the rotational force of the outer gear 22 to the inner gear 23. The planetary gear 24 adjusts the rotational phase of the inner gear 23 with respect to the outer gear 22 by changing the revolution speed, which is the turning speed of the planetary gear 24 with respect to the rotational speed of the inner gear 23.

  The engine 11 is provided with a motor 26 for changing the turning speed of the planetary gear 24. The rotation shaft 27 of the motor 26 is arranged so as to be coaxial with the intake side cam shaft 16, the rotation shaft of the outer gear 22, and the rotation shaft of the inner gear 23. The rotating shaft 27 and the support shaft 25 of the planetary gear 24 are connected via a connecting member 28 that extends in the radial direction of the rotating shaft 27.

  As the motor 26 rotates, the planetary gear 24 revolves around a circular orbit on the outer periphery of the inner gear 23 while rotating around the support shaft 25. The motor 26 is provided with a motor rotation speed sensor 29 that detects the rotation speed RM of the motor 26. A rotation speed signal output from the motor rotation speed sensor 29 is output to the ECU 30.

  When the valve timing is neither retarded nor advanced, the variable valve timing device 18 controls the motor 26 so that the rotational speed RM of the motor 26 matches the rotational speed RC of the intake camshaft 16. When the motor 26 is controlled in this way, the revolution speed of the planetary gear 24 matches the rotation speed of the inner gear 23 and the outer gear 22. The difference in rotational phase between the outer gear 22 and the inner gear 23 is maintained without being retarded or advanced, and the valve timing is maintained without being retarded or advanced.

  When the valve timing is advanced, the variable valve timing device 18 controls the motor 26 so that the rotational speed RM is faster than the rotational speed RC. When the motor 26 is controlled in this way, the revolution speed of the planetary gear 24 becomes faster than the rotation speed of the inner gear 23. The rotational phase of the inner gear 23 with respect to the outer gear 22 is advanced, and the valve timing is advanced.

  When the valve timing is retarded, the variable valve timing device 18 controls the motor 26 so that the rotational speed RM is slower than the rotational speed RC. When the motor 26 is controlled in this way, the revolution speed of the planetary gear 24 becomes slower than the rotation speed of the inner gear 23. The rotational phase of the inner gear 23 with respect to the outer gear 22 is retarded, and the valve timing is retarded.

  The ECU 30 shown in FIG. 1 is mainly composed of a microcomputer. The ECU 30 executes the engine control program stored in the ROM, thereby controlling the fuel injection amount of the fuel injection valve (not shown) and the ignition timing of the spark plug (not shown) according to the engine operating state.

  The ECU 30 executes a control program to feedback control the variable valve timing device 18 so that the actual valve timing of the intake valve matches the target valve timing. In other words, the ECU 30 feedback-controls the variable valve timing device 18 so that the actual cam shaft phase matches the target cam shaft phase. In order to execute this feedback control, a VCT phase that is a crank angle difference between the phase calculation timing and the cam angle signal input timing is calculated.

  As shown in FIG. 3, the ECU 30 includes a phase calculation unit 301, a state determination unit 302, and an abnormality determination unit 303 as functional components.

  Based on the cam angle signal output for each predetermined cam angle, the crank angle signal output for each predetermined crank angle, and the rotation angle signal indicating the rotation angle of the motor 26, the phase calculation unit 301 A VCT phase corresponding to the state of the intake camshaft 16 is calculated. The phase calculation unit 301 calculates an angle change amount of the intake camshaft 16 with respect to the crankshaft 12 based on a difference between a value obtained by doubling the rotation angle of the motor 26 and the rotation angle of the crankshaft 12.

  The state determination unit 302 is in a steady state in which neither the fluctuation of the rotational speed in the engine 11 nor the fluctuation of the cam shaft phase in the variable valve timing device 18 occurs, the fluctuation of the rotational speed in the engine 11, or the variable valve timing device 18. It is determined whether any of the camshaft phase fluctuations is in a transient state.

  When the state determination unit 302 determines that the state is a steady state, the phase calculation unit 301 uses the reference VCT phase when the cam angle signal is output based on the difference between the rotation speed of the motor 26 and the rotation speed of the intake side camshaft 16. The steady VCT phase corresponding to the steady state is calculated by executing a steady process of adding the calculated VCT phase change amount.

  When the state determination unit 302 determines that the state is a transient state, the phase calculation unit 301 performs a transient process of adding the transient phase change amount of the intake camshaft 16 with respect to the crankshaft 12 to the steady VCT phase. A transient VCT phase corresponding to the transient state is calculated.

  The abnormality determination unit 303 determines whether an abnormality has occurred. The abnormality determination unit 303 prohibits the transient process when the difference between the transient VCT phase as the execution result of the transient process and the steady VCT phase as the execution result of the steady process is larger than a predetermined deviation amount. In this embodiment, the ECU 30 is an ECU that also controls the engine, but may be a VCT control ECU that is different from the engine control.

  Subsequently, the processing of the ECU 30 will be described with reference to FIG. In step S101, the state determination unit 302 executes a transient determination process. The transient determination process will be described with reference to FIG.

  In step S201 shown in FIG. 5, the state determination unit 302 determines whether or not the change amount A ≧ the change amount threshold value Ath. The amount of change A is at least one of the amount of change in the accelerator opening, the amount of change in the load on the engine 11, the amount of change in the throttle opening, the amount of change in the rotational speed of the engine 11, and the amount of change in the target camshaft phase. The amount of change.

  If change amount A ≧ change amount threshold value Ath (step S201: YES), the process proceeds to step S202. If change amount A ≧ change amount threshold value Ath is not satisfied (step S201: NO), the process proceeds to step S203.

  In step S202, the state determination unit 302 determines that the variable valve timing device 18 is in a transient state. In step S203, the state determination unit 302 determines whether or not the VCT phase VT has converged to the target phase. If the VCT phase VT has converged to the target phase, the process proceeds to step S204. If the VCT phase VT has not converged to the target phase, the process proceeds to step S202.

  In step S204, the state determination unit 302 determines that the variable valve timing device 18 is in a steady state. When the process of step S202 or step S204 ends, the transient determination process ends, and the process proceeds to step S102 of FIG.

  In step S102, the state determination unit 302 determines whether or not transient control is necessary. If the processing result of step S101 is “determined as a transient state”, the state determination unit 302 determines that transient control is necessary. If the processing result of step S101 is “determined as steady state”, state determination unit 302 determines that transient control is not necessary.

  If transient control is required (step S102: YES), the process proceeds to step S103. If transient control is not required (step S102: NO), the process proceeds to step S109.

  In step S109, the phase calculation unit 301 executes a steady VCT phase VTconst calculation process corresponding to the steady state. The steady VCT phase VTconst calculation process corresponding to the steady state will be described with reference to FIG.

  In step S301 illustrated in FIG. 6, the phase calculation unit 301 determines whether or not the engine 11 is rotating. Whether or not the engine 11 is rotating is determined, for example, based on whether or not the engine speed calculated from the output period of the crank angle signal output from the crank angle sensor 20 is zero.

  If the engine 11 is rotating (step S301: YES), the process proceeds to step S302. If the engine 11 is not rotating (step S301: NO), the process proceeds to step S308.

  In step S302, the phase calculation unit 301 determines whether a cam angle signal output from the cam angle sensor 19 has been input. If a cam angle signal has been input (step S302: YES), the process proceeds to step S303. If no cam angle signal is input (step S302: NO), the process proceeds to step S307.

In step S303, the phase calculation unit 301 stores the cam angle signal input time Tcam and the crank angle signal input time Tcrk in a memory (not shown) of the ECU 30. In step S304 following step S303, the phase calculation unit 301 calculates a time difference TVT [s] of the cam angle signal input time with respect to the crank angle signal input time by the following equation (f02).
TVT [s] = Tcrk-Tcam + K. . . (F02)
K is a correction amount for correcting a difference in response delay between the cam angle sensor 19 and the crank angle sensor 20.

In step S305 following step S304, the phase calculation unit 301 uses the time difference TVT [s] of the cam angle signal with respect to the crank angle signal to calculate the rotation phase VTC of the cam angle signal with respect to the crank angle signal by the following equation (f03). calculate.
VTC [degCA] = TVT [s] / T30 [s] × 30 (degCA). . . (F03)
T30 [s] is the time required for the crankshaft 12 to rotate 30 [degCA], and is calculated based on the output signal of the crank angle sensor 20.

  In step S306 following step S305, the VCT phase is calculated every time the phase calculation unit 301 calculates VTC [degCA], which is the reference VCT phase when the cam angle signal is output, in other words, every time the cam angle signal is input. The change amounts ΔVTH [degCA] and ΔVTS [degCA] are both reset to “0”.

  If it is determined in step S302 that no cam angle signal has been input, the process proceeds to step S307. In step S307, the phase calculation unit 301 executes a calculation process of the VCT phase change amount ΔVTH [degCA]. A calculation process of the VCT phase change amount ΔVTH [degCA] will be described with reference to FIG.

In step S401 shown in FIG. 7, the phase calculation unit 301 calculates a rotational speed difference DMC [rpm] between the rotational speed RM [rpm] of the motor 26 and the rotational speed RC [rpm] of the intake camshaft 16 by the following formula ( f05).
DMC [rpm] = RM [rpm] -RC [rpm]. . . (F05)

The rotation speed RC [rpm] of the intake camshaft 16 uses a value of the rotation speed [rpm] × 1/2 of the crankshaft 12 calculated based on the output period of the crank angle signal output from the crank angle sensor 20. .
RC [rpm] = Crankshaft rotation speed [rpm] × 1/2. . . (F06)

In step S402 following step S401, the phase calculation unit 301 converts the rotational speed difference DMC [rpm] into a rotational difference RVT [rev / s] per second by the following equation (f07).
RVT [rev / s] = DMC [rpm] / 60. . . (F07)

In step S403 following step S402, the phase calculation unit 301 calculates the VCT phase change amount dVTH [degCA] per calculation cycle P [s] of the VCT phase change amount ΔVTH [degCA] by the following equation (f08).
dVTH [degCA] = RVT [rev / s] / G × 720 [degCA] × P [s]. . . (F08)
G is a reduction ratio of the phase variable mechanism 21 and is a ratio between a relative rotation amount of the motor 26 with respect to the intake camshaft 16 and a change amount of the camshaft phase.

In step S404 following step S403, the VCT phase change amount dVTH [degCA] per calculation cycle P [s] is integrated to calculate the VCT phase change amount ΔVTH [degCA] by the following equation (f09).
ΔVTH [degCA] = ΔVTH [degCA] + dVTH [degCA]. . . (F09)
When the process of step S404 ends, the calculation process of the VCT phase change amount ΔVTH [degCA] ends, and the process proceeds to step S309 of FIG.

  Returning to FIG. 6, the description will be continued. If it is determined in step S301 that the engine 11 is not rotating, the process proceeds to step S308. In step S308, the phase calculation unit 301 executes a calculation process of the VCT phase change amount ΔVTS [degCA]. The calculation process of the VCT phase change amount ΔVTS [degCA] will be described with reference to FIG.

In step S501 shown in FIG. 8, the phase calculation unit 301 uses only the rotation speed RM [rpm] of the motor 26 to convert the rotation difference RVT [rev / s] per second by the following equation (f10). .
RVT [rev / s] = RM [rpm] / 60. . . (F10)

In step S502 following step S501, the phase calculation unit 301 calculates the VCT phase change amount dVTS [degCA] per calculation cycle P [s] of the VCT phase change amount ΔVTS [degCA] by the following equation (f11).
dVTS [degCA] = RVT [rev / s] / G × 720 [degCA] × P [s]. . . (F11)
G is a reduction ratio of the phase variable mechanism 21.

In step S503 following step S502, the VCT phase change amount dVTS [degCA] per calculation cycle P [s] is integrated, and the VCT phase change amount ΔVTS [degCA from the last cam angle signal output before the engine stop to the present time. ] Is calculated by the following equation (f12).
ΔVTS [degCA] = ΔVTS [degCA] + dVTS [degCA]. . . (F12)
When the process of step S503 ends, the calculation process of the VCT phase change amount ΔVTS [degCA] ends, and the process proceeds to step S309 of FIG.

In step S309 following step S306, step S307, and step S308, the final steady VCT phase VTconst [degCA] is calculated by the following equation (f13). The calculated steady VCT phase VTconst [degCA] is stored in the memory.
VTconst [degCA] = VTC [degCA] + ΔVTH [degCA] + ΔVTS [degCA]. . . (F13)

  When the cam angle signal is input, ΔVTH = 0 and ΔVTS = 0 by the reset process in step S306, so that VTconst = VTC. When no cam angle signal is input, ΔVTS = 0, so VTconst = VTC + ΔVTH. Since ΔVTH = 0 while the engine is stopped, VTconst = VTC + ΔVTS.

  Each time the cam angle signal is input during engine rotation, the reference VCT phase VTC when the cam angle signal is output is calculated based on the cam angle signal and the crank angle signal. When the cam angle signal is input, the VCT phase change amounts ΔVTH and ΔVTS are reset to 0 by the reset process in step S306, so that the reference VCT phase VTC when the cam angle signal is output becomes the steady VCT phase VTconst as it is.

  During a period when the cam angle signal is not input, the VCT phase change amount dVTH per calculation cycle is calculated and integrated based on the rotational speed difference DMC between the motor 26 and the intake camshaft 16. The steady VCT phase VTconst is obtained by adding the integrated value of dVTH, which is the subsequent VCT phase change amount ΔVTH, to the reference VCT phase VTC when the latest cam angle signal is output. As a result, the steady VCT phase VTconst can be calculated continuously and accurately even during a period in which the cam angle signal is not output.

  When the engine is stopped, the steady VCT phase VTconst is obtained by adding the subsequent VCT phase change amount ΔVTS to the reference VCT phase VTC when the last cam angle signal is output before the stop. Therefore, even when the engine is stopped, the steady VCT phase VTconst is It is possible to calculate with high accuracy.

  When the process of step S309 ends, the steady VCT phase VTconst calculation process ends, and the process proceeds to step S110 of FIG.

  Returning to FIG. 4, the description will be continued. If it is determined in step S102 that excessive control is required, the process proceeds to step S103.

  In step S103, the phase calculation unit 301 performs a calculation process of the transient phase change amount ΔVT. The transient phase change amount ΔVT is an angle change amount of the camshaft with respect to the crankshaft 12. The calculation process of the transient phase change amount ΔVT will be described with reference to FIG.

  In step S601 illustrated in FIG. 9, the phase calculation unit 301 calculates the motor shaft rotation angle ΔMo [deg] of the motor 26. The motor shaft rotation angle ΔMo [deg] is calculated based on the rotation speed signal output from the motor rotation speed sensor 29. More specifically, it is calculated as an angle difference in the advance direction or an angle difference in the retard direction from the rotation angle in the steady state.

  In step S602 following step S601, the phase calculation unit 301 calculates the crankshaft rotation angle ΔCr [degCA]. The crankshaft rotation angle ΔCr [degCA] is calculated based on the crank angle signal output from the crank angle sensor 20. More specifically, it is calculated as an angle difference in the advance direction or an angle difference in the retard direction from the rotation angle in the steady state.

In step S603 following step S602, the phase calculation unit 301 calculates the transient phase change amount ΔVT [degCA] based on the following equation (f14).
ΔVT [degCA] = (2 × ΔMo [deg] −ΔCr [degCA]) / G. . . (F14)
G is a reduction ratio of the phase variable mechanism 21.

  When the process of step S603 ends, the transient phase change amount ΔVT calculation process ends, and the process proceeds to step S104 of FIG.

  In step S104 illustrated in FIG. 4, the phase calculation unit 301 executes a process of reading the steady VCT phase VTconst from the memory. The steady VCT phase VTconst is calculated by the procedure described with reference to FIG. 6, stored in the memory, and updated at a predetermined calculation cycle.

In step S105 following step S104, the phase calculation unit 301 calculates the transient VCT phase VTtrans by the following equation (f15).
VTtrans [degCA] = VTconst [degCA] + ΔVT [degCA]. . . (F15)

  In step S106 following step S105, the abnormality determination unit 303 executes abnormality determination processing. The abnormality determination process will be described with reference to FIG.

In step S701 illustrated in FIG. 10, the abnormality determination unit 303 calculates a deviation amount VTgap [degCA] by the following equation (f16).
VTgap [degCA] = VTconst [degCA] −VTtrans [degCA]. . . (F16)

  The steady VCT phase VTconst [degCA] is calculated in step S109. The transient VCT phase VTtrans [degCA] is calculated in step S105.

  In step S702 following step S701, the abnormality determination unit 303 determines whether or not | deviation amount VTgap | ≧ deviation threshold value VTth. If | divergence amount VTgap | ≧ deviation threshold value VTth (step S702: YES), the process proceeds to step S703. move on.

  In step S703, the abnormality determination unit 303 determines that abnormality treatment is necessary. In step S704, the abnormality determination unit 303 determines that the abnormality treatment is unnecessary. When the processes in steps S703 and S704 are finished, the abnormality determination process is finished, and the process proceeds to step S107 in FIG.

  In step S107 shown in FIG. 4, the abnormality determination unit 303 determines whether or not an abnormality treatment is necessary. If no abnormal treatment is required (step S107: YES), the process proceeds to step S108. If abnormal treatment is necessary (step S107: NO), the process proceeds to step S110.

  In step S108, the phase calculation unit 301 determines the VCT phase VT corresponding to the transient state as the transient VCT phase VTtrans. When the process of step S108 ends, the process returns.

  In step S110, the phase calculation unit 301 determines the VCT phase VT corresponding to the steady state as the steady phase VTconst. When the process of step S110 ends, the process returns.

  The ECU 30 in this embodiment corresponds to a control device. The ECU 30 that is a control device of the engine 11 includes a state determination unit 302 and a phase calculation unit 301. The state determination unit 302 changes the rotational speed of the engine 11 and changes the camshaft phase, which is the rotational phase of the intake camshaft 16 with respect to the crankshaft 12 of the engine 11, so that intake air that is driven to open and close by the intake camshaft 16. The camshaft phase fluctuation in the variable valve timing device 18 that changes the valve timing of the valve and / or the exhaust valve is a transient state in which at least one of the fluctuations occurs, or the rotation speed fluctuation in the engine 11 is also the camshaft phase fluctuation. It is determined whether the steady state is not generated.

  The phase calculation unit 301 includes a cam angle signal input every predetermined cam angle, a crank angle signal input every predetermined crank angle, a rotation angle signal indicating a rotation angle of the motor 26 that changes the cam shaft phase, Based on the above, a VCT phase that is a crank angle difference between the phase calculation timing and the cam angle signal input timing is calculated.

  When the state determination unit 302 determines that the steady state is in effect, the phase calculation unit 301 calculates a steady VCT phase corresponding to the steady state by executing a steady process. When the state determination unit 302 determines that the state is a transient state, the phase calculation unit 301 performs a transient process of adding the transient phase change amount of the intake camshaft 16 with respect to the crankshaft 12 to the steady VCT phase. A transient VCT phase corresponding to the transient state is calculated.

  According to the present embodiment, in the transient state where the camshaft phase fluctuates, the transient process of adding the transient phase change amount is executed with respect to the steady VCT phase corresponding to the steady state. A transient VCT phase can be calculated. Since the steady VCT phase is calculated in correspondence with the steady state, errors caused by fluctuations in engine speed and camshaft phase can be minimized. Since the transient phase change amount of the intake camshaft 16 with respect to the crankshaft 12 in the transient state is added to the steady VCT phase with high accuracy in this way, it is possible to calculate a more accurate VCT phase even in the transient state. it can.

  In the present embodiment, the phase calculation unit 301 performs a reference process based on a time difference between a cam angle signal input timing at which a cam angle signal is input and a timing at which a crank angle signal corresponding to a phase calculation timing is input. The VCT phase is calculated, and the steady VCT phase is calculated by adding the VCT phase change amount calculated based on the difference between the rotation speed of the motor 26 and the rotation speed of the cam shaft to the reference VCT phase.

  By using the VCT phase change amounts ΔVTH and ΔVTS, it is possible to more accurately reflect the result of the retard angle control or the advance angle control and calculate the steady VCT phase. Accordingly, the transient VCT phase is calculated by adding the transient phase change amount to the more accurately calculated steady-state VCT phase, so that a more accurate VCT phase can be calculated even during the transient.

  In the present embodiment, the phase calculation unit 301 calculates a transient phase change amount based on a difference between a value obtained by doubling the rotation angle of the motor 26 and the rotation angle of the crankshaft 12 as a transient process, and calculates in advance. Is added to the stationary VCT phase.

  Since the transient phase change amount is calculated based on the difference between the rotation angle of the motor 26 and the rotation angle of the crankshaft 12, the transient phase change amount corresponding to the case where the rotation angle difference between the crankshaft 12 and the motor 26 fluctuates. Can be calculated.

  In the present embodiment, the state determination unit 302 changes the accelerator opening, the load change on the engine 11, the throttle opening change, the engine speed change, and the target camshaft phase change. Based on at least one change amount of, it is determined whether it is a steady state or a transient state.

  As in the present embodiment, at least one of the change amount of the accelerator opening, the change amount of the load on the engine 11, the change amount of the throttle opening, the change amount of the engine speed, and the change amount of the target camshaft phase. By making a determination based on the amount of change, it is possible to determine a transition to a transient state due to a change in the rotational speed of the engine 11 or a change in the camshaft phase.

  In the present embodiment, the state determination unit 302 determines that the transient VCT phase has converged to the target VCT phase, regardless of the change amount state, that it is in a steady state. This is because if the transient VCT phase converges to the target camshaft phase, the VCT phase can be grasped without performing transient control.

  The present embodiment further includes an abnormality determination unit 303 that determines whether an abnormality has occurred. When the abnormality determination unit 303 determines that an abnormality has occurred, the phase calculation unit 301 prohibits transient processing. This is because, if it is determined whether or not a transient state occurs even when an abnormality occurs due to disconnection or the like of the motor 26, the transient VCT phase calculation error may exceed the allowable range.

  In the present embodiment, the abnormality determination unit 303 generates an abnormality when the deviation between the transient VCT phase as the execution result of the transient process and the steady VCT phase as the execution result of the steady process is larger than a predetermined deviation amount. It can be judged. Further, when the deviation between the VCT phase obtained based only on the crank angle signal and the cam angle signal and the transient VCT phase as a result of executing the transient processing is larger than a predetermined deviation amount, it is determined that an abnormality has occurred. You can also. If the VCT phase calculated without using the signal used for the transient processing is used as a reference, it is possible to accurately grasp the occurrence of abnormality such as disconnection of the motor 26.

  The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Those in which those skilled in the art appropriately modify the design of these specific examples are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each of the specific examples described above and their arrangement, conditions, shape, and the like are not limited to those illustrated, and can be changed as appropriate. Each element included in each of the specific examples described above can be appropriately combined as long as no technical contradiction occurs.

11: Engine 12: Crankshaft 16: Intake side camshaft 18: Variable valve timing device 301: Phase calculation unit 302: State determination unit

Claims (7)

An engine control device,
The intake valve that is driven to open and close by the camshaft by changing the rotational speed of the engine (11) and the camshaft phase that is the rotational phase of the camshaft (16) with respect to the crankshaft (12) of the engine, and / or Alternatively, a transient state in which at least one of the cam shaft phase fluctuations in the variable valve timing device (18) that changes the valve timing of the exhaust valve is generated, or fluctuations in the rotational speed of the engine also occur in the cam shaft phase. A state determination unit (302) for determining whether or not a steady state in which no fluctuation has occurred;
Based on a cam angle signal input for each predetermined cam angle, a crank angle signal input for each predetermined crank angle, and a rotation angle signal indicating the rotation angle of the motor (26) that changes the cam shaft phase. A phase calculation unit (301) that calculates a VCT phase that is a crank angle difference between the phase calculation timing and the cam angle signal input timing,
When the state determination unit determines that the steady state is present, the phase calculation unit calculates a steady VCT phase corresponding to the steady state by executing a steady process,
When the state determination unit determines that the state is the transient state, the phase calculation unit performs a transient process of adding a transient phase change amount of the camshaft with respect to the crankshaft to the steady VCT phase. A control device for calculating a transient VCT phase corresponding to the transient state. The control device according to claim 1,
The phase calculation unit calculates a reference VCT phase based on a time difference between a cam angle signal input timing at which the cam angle signal is input and a timing at which a crank angle signal corresponding to a phase calculation timing is input as the steady process. A control device that calculates the steady VCT phase by calculating and adding a VCT phase change amount calculated based on a difference between the rotation speed of the motor and the rotation speed of the cam shaft to the reference VCT phase. The control device according to claim 1 or 2,
The phase calculation unit calculates the transient phase change amount as the transient process based on a difference between a value obtained by doubling the rotation angle of the motor and a rotation angle of the crankshaft, A controller that adds to the steady VCT phase. The control device according to any one of claims 1 to 3,
The state determination unit includes at least one of an accelerator opening change amount, a load change amount for the engine, a throttle opening change amount, an engine speed change amount, and a target cam shaft phase change amount. A control device that determines whether the state is the steady state or the transient state based on a change amount. The control device according to claim 4,
The state determination unit determines that the transient VCT phase has converged to a target VCT phase, regardless of the change amount state, and determines that the state is in the steady state. The control device according to any one of claims 1 to 5,
Further, an abnormality determination unit (303) for determining occurrence of abnormality is provided,
When the abnormality determining unit determines that an abnormality has occurred, the phase calculating unit prohibits the transient processing. The control device according to claim 6,
The abnormality determination unit determines that an abnormality has occurred when a deviation between the transient VCT phase as the execution result of the transient process and the steady VCT phase as the execution result of the steady process is larger than a predetermined deviation amount. Control device to judge.

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