JP2008261244A - Control unit and control method for variable valve timing mechanism, program for implementing its control method and recording medium on which its program is recorded - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To learn the most retarded phase without deteriorating emission performance. <P>SOLUTION: An ECU executes a program including a step (S102) of controlling an intake VVT mechanism so that a phase changes in a second range of including no most retarded phase when driving an engine (YES in S100), a step (S114) of controlling the intake VVT mechanism so that the phase is brought to the mechanically determined most retarded phase when executing a fuel cut (YES in S110) or when a hybrid car travels in a second traveling mode of using driving force of only an MG 2 in a state of stopping the engine (YES in S112), and a step (S116) of learning a phase detected by a cam position sensor as the most retarded phase. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for a variable valve timing mechanism, a control method, a program that realizes the method, and a recording medium that records the program, and in particular, a technique for learning a phase detected by a detector that detects the phase of the valve. About.

  Conventionally, VVT (Variable Valve Timing) is known in which the phase (crank angle) at which an intake valve or an exhaust valve opens and closes is changed according to the operating state. In general, in VVT, the phase is changed by rotating a camshaft for opening and closing an intake valve and an exhaust valve relative to a sprocket or the like. The camshaft is rotated by an actuator such as a hydraulic pressure or an electric motor.

  By the way, the range in which the phase can change may change due to the influence of the elongation of the chain connecting the crankshaft and the camshaft. Accordingly, the phase of the most retarded angle and the phase of the most advanced angle that are mechanically determined change with the aging of the internal combustion engine. In this case, for example, the output value from the cam position sensor stored as the output value corresponding to the most retarded phase may differ from the output value corresponding to the actual most retarded phase. Therefore, it is necessary to periodically learn the phase detected by the cam position sensor at the mechanically determined most retarded phase.

  Japanese Patent Laying-Open No. 2001-82190 (Patent Document 1) discloses a valve timing control device that performs learning for a reference position at an early stage when a learning value for deviation from the reference position of a variable valve timing mechanism is cleared. The valve timing control device described in Patent Document 1 learns a deviation between the reference position of the variable valve timing mechanism and the actual valve timing calculated from the crank angle and the cam position, calibrates the actual valve timing, and calibrates the actual valve timing. Is a valve timing control device for the engine that controls the variable valve timing mechanism so as to converge to the target valve timing set based on the engine operating state. The valve timing control device forcibly sets the target valve timing for a set time after engine startup when the learning value for learning the deviation between the reference position of the variable valve timing mechanism and the actual valve timing is cleared. A learning forcing unit that performs learning as a reference position of the timing mechanism is included.

According to the valve timing control device described in this publication, when the learning value for learning the deviation between the reference position of the variable valve timing mechanism and the actual valve timing calculated from the crank angle and the cam position is cleared, the engine is started. During a later set time, learning is performed with the target valve timing forced to be the reference position of the variable valve timing mechanism. As a result, the deviation of the actual valve timing from the reference position can be learned early and reflected in the valve timing control. Therefore, it is possible to ensure the control accuracy and sufficiently bring out the engine output performance.
JP 2001-82190 A

  By the way, in order to reduce the vibration at the time of starting, it is conceivable to reduce the compression ratio at the time of cranking by largely retarding the phase of the intake valve at the time of starting. In an internal combustion engine in which the phase is controlled in this way, a phase to be used as a phase reference, such as the most retarded phase of the valve, is not suitable as a phase used during driving. In this internal combustion engine, as described in JP-A-2001-82190, when the phase is learned after the internal combustion engine is started, that is, in a state in which the internal combustion engine is driven, the phase of the valve is more than necessary. Can be retarded. In this case, the emission performance is deteriorated.

  The present invention has been made to solve the above-described problems, and an object thereof is to realize a control apparatus, a control method, and a method for a variable valve timing mechanism that can prevent emission performance and the like from being deteriorated. And a recording medium on which the program is recorded.

  According to a first aspect of the present invention, there is provided a control device for a variable valve timing mechanism, wherein a phase of at least one of an intake valve and an exhaust valve of an internal combustion engine is a first range from a first phase to a second phase. It is a control device of a variable valve timing mechanism that can be changed with When the internal combustion engine is driven, the control device is configured to control the valve phase to change within a second range not including the third phase, and when the internal combustion engine is not driven. And a detector for detecting the phase of the valve in a state in which the phase of the valve is controlled to become the third phase. Means for learning the detected phase. The control method for the variable valve timing mechanism according to the fifth invention has the same requirements as the control device for the variable valve timing mechanism according to the first invention.

  According to the first or fifth aspect of the present invention, the variable valve timing mechanism changes the phase of at least one of the intake valve and the exhaust valve of the internal combustion engine from the first phase to the second phase. Change within the range. When the internal combustion engine is driven, the phase of the valve is changed in a second range that does not include the third phase. When the internal combustion engine is not driven, the valve phase is controlled to be the third phase. Thereby, since the internal combustion engine is not driven, the phase of the valve can be set to the third phase in a state where the emission performance is hardly deteriorated. In a state where the phase of the valve is controlled to be the third phase, the phase detected by the detector that detects the phase of the valve is learned. Therefore, when learning the phase detected by the detector in the third phase, the emission performance or the like can be prevented from deteriorating. As a result, it is possible to provide a control device or control method for a variable valve timing mechanism that can prevent emission performance from deteriorating.

  In the control apparatus for the variable valve timing mechanism according to the second invention, in addition to the configuration of the first invention, the control means is configured such that the valve phase is the third phase when the fuel injection in the internal combustion engine is stopped. Means for controlling to be. The control method for the variable valve timing mechanism according to the sixth aspect of the invention has the same requirements as the control apparatus for the variable valve timing mechanism according to the second aspect of the invention.

  According to the second or sixth invention, the phase detected by the detector in the third phase can be learned when the emission performance or the like does not deteriorate due to the stop of fuel injection in the internal combustion engine. .

  In the control apparatus for the variable valve timing mechanism according to the third aspect of the invention, in addition to the configuration of the first aspect, the internal combustion engine is in a state in which the internal combustion engine is stopped in the first mode in which the internal combustion engine travels using the driving force of the internal combustion engine. The vehicle is mounted on a vehicle that can select the second mode of traveling using a driving force of a driving source different from that of the internal combustion engine. The control means includes means for controlling the valve phase to be the third phase when the vehicle travels in the second mode. The control method for the variable valve timing mechanism according to the seventh invention has the same requirements as the control device for the variable valve timing mechanism according to the third invention.

  According to the third or seventh aspect of the invention, detection is performed in the third phase when emission performance or the like is not deteriorated by traveling using a driving force of a driving source different from that of the internal combustion engine while the internal combustion engine is stopped. The phase detected by the detector can be learned.

  In the control apparatus for a variable valve timing mechanism according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the third phase is the most retarded phase in the first range. The control method for the variable valve timing mechanism according to the eighth invention has the same requirements as those of the control device for the variable valve timing mechanism according to the fourth invention.

  According to the fourth or eighth aspect, the phase detected by the detector at the most retarded phase can be learned.

  A program according to a ninth aspect is a program for causing a computer to realize the control method according to any of the fifth to eighth aspects, and the recording medium according to the tenth aspect is any one of the fifth to eighth aspects. A computer-readable recording medium recording a program for causing a computer to implement the control method according to the invention.

  According to the ninth or tenth invention, the variable valve timing mechanism control method according to any one of the fifth to eighth inventions can be realized using a computer (which may be general purpose or dedicated).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, a power train of a hybrid vehicle equipped with a control device according to an embodiment of the present invention will be described. The control device according to the present embodiment is realized, for example, when ECU 100 executes a program recorded in ROM (Read Only Memory) 102 of ECU (Electronic Control Unit) 100. ECU 100 may be divided into a plurality of ECUs. Further, a program executed by the ECU 1000 may be recorded on a recording medium such as a CD (Compact Disc) or a DVD (Digital Versatile Disc) and distributed to the market.

  As shown in FIG. 1, the power train includes an engine 1000, an MG (Motor Generator) (1) 200, and a power split mechanism 300 that synthesizes or distributes torque between the engine 1000 and the MG (1) 200. , MG (2) 400 and transmission 500 are mainly configured.

  The engine 1000 is a known power device that burns fuel and outputs motive power, and is configured to be able to electrically control operating conditions such as throttle opening (intake amount), fuel supply amount, and ignition timing. Yes. The control is performed, for example, by the ECU 100 mainly including a microcomputer. Details of the engine 1000 will be described later.

  The MG (1) 200 is a three-phase AC rotating electric machine as an example, and is configured to generate a function as an electric motor (motor) and a function as a generator (generator). It is connected to a power storage device 700 such as a battery via an inverter 210. By controlling the inverter 210, the output torque or regenerative torque of the MG (1) 200 is set appropriately. The control is performed by the ECU 100. The stator (not shown) of MG (1) 200 is fixed and is not rotated.

  The power split mechanism 300 includes a sun gear (S) 310 that is an external gear, a ring gear (R) 320 that is an internal gear arranged concentrically with the sun gear (S) 310, and the sun gear (S). This is a known gear mechanism that generates a differential action by using a carrier (C) 330 that rotates and revolves a pinion gear meshing with 310 and a ring gear (R) 320 as three rotating elements. The output shaft of the engine 1000 is connected to a carrier (C) 330 as a first rotating element via a damper. In other words, the carrier (C) 330 is an input element.

  On the other hand, the rotor (not shown) of MG (1) 200 is connected to sun gear (S) 310 which is the second rotating element. Therefore, the sun gear (S) 310 is a so-called reaction force element, and the ring gear (R) 320 that is the third rotation element is an output element. The ring gear (R) 320 is connected to an output shaft 600 connected to drive wheels (not shown).

  FIG. 2 shows an alignment chart of the power split mechanism 300. As shown in FIG. 2, when the reaction torque generated by MG (1) 200 is input to sun gear (S) 310 with respect to the torque output from engine 1000 input to carrier (C) 330, these torques are added or subtracted. The torque having the magnitude appears in the ring gear (R) 320 serving as an output element. In that case, the rotor of MG (1) 200 rotates by the torque, and MG (1) 200 functions as a generator. When the rotation speed (output rotation speed) of the ring gear (R) 320 is constant, the rotation speed of the engine 1000 is continuously (steplessly) varied by changing the rotation speed of the MG (1) 200. ) Can be changed. That is, the control for setting the engine speed of the engine 1000 to, for example, the engine speed with the best fuel efficiency can be performed by controlling the MG (1) 200. The control is performed by the ECU 100.

  If engine 1000 is stopped during traveling, MG (1) 200 is rotating in the reverse direction, and when MG (1) 200 is made to function as an electric motor and torque is output in the forward rotation direction, carrier ( C) Torque in a direction for rotating the engine 1000 connected to 330 acts on the engine 1000, and the engine 1000 can be started (motored or cranked) by the MG (1) 200. In that case, torque in a direction to stop the rotation acts on the output shaft 600. Therefore, the driving torque for traveling can be maintained by controlling the torque output by MG (2) 400, and at the same time, engine 1000 can be started smoothly. This type of hybrid type is called a mechanical distribution type or a split type.

  Returning to FIG. 1, MG (2) 400 is a three-phase AC rotating electric machine as an example, and is configured to generate a function as a motor and a function as a generator. A power storage device 700 such as a battery is connected via an inverter 310. By controlling the inverter 310, the power running and regeneration and the torque in each case are controlled. The stator (not shown) of MG (2) 400 is fixed and is not rotated.

  The transmission 500 is configured by a set of Ravigneaux planetary gear mechanisms. A first sun gear (S1) 510 and a second sun gear (S2) 520, which are external gears, are provided, and the first pinion 531 meshes with the first sun gear (S1) 510, and the first The pinion 531 meshes with the second pinion 532, and the second pinion 532 meshes with the ring gear (R) 540 arranged concentrically with the sun gears 510 and 520.

  Each pinion 531 and 532 is held by a carrier (C) 550 so as to rotate and revolve freely. Further, the second sun gear (S 2) 520 is meshed with the second pinion 532. Therefore, the first sun gear (S1) 510 and the ring gear (R) 540 form a mechanism corresponding to the double pinion type planetary gear mechanism together with the pinions 531 and 532, and the second sun gear (S2) 520 and the ring gear (R). 540 and the second pinion 532 constitute a mechanism corresponding to a single pinion planetary gear mechanism.

  Further, the transmission 500 is provided with a B1 brake 561 that selectively fixes the first sun gear (S1) 510 and a B2 brake 562 that selectively fixes the ring gear (R) 540. These brakes 561 and 562 are so-called friction engagement elements that generate an engagement force by a friction force, and a multi-plate type engagement device or a band type engagement device can be adopted. And these brakes 561 and 562 are comprised so that the torque capacity may change continuously according to the engaging force by oil_pressure | hydraulic. Further, the above-described MG (2) 400 is connected to the second sun gear (S2) 520. Carrier (C) 550 is connected to output shaft 600.

  Therefore, in the above-described transmission 500, the second sun gear (S2) 520 is a so-called input element, and the carrier (C) 550 is an output element. By engaging the B1 brake 561, the transmission ratio is “ A high speed stage greater than 1 "is set. By engaging the B2 brake 562 instead of the B1 brake 561, a low speed stage having a higher gear ratio than the high speed stage is set.

  The speed change between the respective speeds is executed based on a traveling state such as a vehicle speed and a required driving force (or accelerator opening). More specifically, the shift speed region is determined in advance as a map (shift diagram), and control is performed so as to set one of the shift speeds according to the detected driving state.

  FIG. 3 shows an alignment chart of the transmission 500. As shown in FIG. 3, if the ring gear (R) 540 is fixed by the B2 brake 562, the low speed stage L is set, and the torque output from the MG (2) 400 is amplified according to the gear ratio, and is output to the output shaft 600. Added. On the other hand, if the first sun gear (S1) 510 is fixed by the B1 brake 561, the high speed stage H having a smaller gear ratio than the low speed stage L is set. Since the gear ratio at the high speed stage H is also larger than “1”, the torque output from the MG (2) 400 is increased according to the gear ratio and added to the output shaft 600.

  In the state where the gears L and H are constantly set, the torque applied to the output shaft 600 is a torque obtained by increasing the output torque of the MG (2) 400 according to the gear ratio. In the shift transition state, the torque is affected by the torque capacity at each brake 561 and 562, the inertia torque accompanying the change in the rotational speed, and the like. Further, the torque applied to the output shaft 600 is a positive torque in the driving state of the MG (2) 400, and is a negative torque in the driven state.

  In the present embodiment, the hybrid vehicle has a first traveling mode that uses only the driving force of engine 1000, a second traveling mode that uses only the driving force of MG (2) 400 while engine 1000 is stopped, engine 1000 and MG. (2) The vehicle travels in any one of the third travel modes using both driving forces of 400. The travel mode is selected based on various parameters such as the accelerator opening and the remaining capacity of power storage device 700.

  In addition, about the selection method of driving modes, what is necessary is just to utilize a well-known technique in the technical field of a hybrid vehicle, Therefore Here, further detailed description is not repeated. Further, the number of modes is not limited to three.

The engine 1000 will be further described with reference to FIG.
The engine 1000 is a V-type 8-cylinder engine in which “A” bank 1010 and “B” bank 1012 are each provided with a group of four cylinders. An engine other than a V-type 8-cylinder engine may be used.

  Engine 1000 receives air from air cleaner 1020. The intake air amount is adjusted by a throttle valve 1030. The throttle valve 1030 is an electronic throttle valve that is driven by a motor.

  Air is introduced into the cylinder 1040 through the intake passage 1032. Air is mixed with fuel in a cylinder 1040 (combustion chamber). Fuel is directly injected from the injector 1050 into the cylinder 1040. That is, the injection hole of the injector 1050 is provided in the cylinder 1040.

  Fuel is injected during the intake stroke. Note that the timing of fuel injection is not limited to the intake stroke. In this embodiment, engine 1000 will be described as a direct injection engine in which an injection hole of injector 1050 is provided in cylinder 1040. In addition to direct injection injector 1050, a port injection injector is provided. May be. Further, only a port injection injector may be provided.

  The air-fuel mixture in the cylinder 1040 is ignited by the spark plug 1060 and burned. The air-fuel mixture after combustion, that is, the exhaust gas is purified by the three-way catalyst 1070 and then discharged outside the vehicle. The piston 1080 is pushed down by the combustion of the air-fuel mixture, and the crankshaft 1090 rotates.

  An intake valve 1100 and an exhaust valve 1110 are provided at the top of the cylinder 1040. Intake valve 1100 is driven by intake camshaft 1120. The exhaust valve 1110 is driven by an exhaust camshaft 1130. Intake camshaft 1120 and exhaust camshaft 1130 are connected by a chain, gear, or the like, and rotate at the same rotational speed.

  The phase (opening / closing timing) of intake valve 1100 is controlled by intake VVT mechanism 2000 provided on intake camshaft 1120. The phase of the exhaust valve 1110 is controlled by an exhaust VVT mechanism 3000 provided on the exhaust camshaft 1130.

  In the present embodiment, intake camshaft 1120 and exhaust camshaft 1130 are rotated by the VVT mechanism, whereby the phases of intake valve 1100 and exhaust valve 1110 are controlled. The method for controlling the phase is not limited to this.

  Intake VVT mechanism 2000 is operated by electric motor 2060 (not shown in FIG. 4). Electric motor 2060 is controlled by ECU 100. The current and voltage of the electric motor 2060 are detected by an ammeter (not shown) and a voltmeter (not shown) and input to the ECU 100.

  The exhaust VVT mechanism 3000 is operated by hydraulic pressure. Intake VVT mechanism 2000 may be hydraulically operated, and exhaust VVT mechanism 3000 may be operated by an electric motor.

  ECU 100 receives a signal representing the rotation speed and crank angle of crankshaft 1090 from crank angle sensor 5000. Further, ECU 100 receives from cam position sensor 5010 a signal indicating the phase of intake camshaft 1120 and exhaust camshaft 1130 (the position of the camshaft in the rotational direction) (signal indicating the phase of intake valve 1100 and exhaust valve 1110). Is done. In addition, signals representing the rotational speeds of intake camshaft 1120 and exhaust camshaft 1130 are input from cam position sensor 5010.

  Further, ECU 100 receives a signal representing the water temperature (cooling water temperature) of engine 1000 from water temperature sensor 5020 and a signal representing the intake air amount of engine 1000 (the amount of air sucked into engine 1000) from air flow meter 5030. Is done.

  Further, the ECU 100 receives a signal representing the output shaft rotational speed of the electric motor 2060 from the rotational speed sensor 5040.

  Based on signals input from these sensors, a map and a program stored in a memory (not shown), the ECU 100 controls the throttle opening, ignition timing, fuel injection so that the engine 1000 enters a desired operating state. The timing, fuel injection amount, intake valve 1100 phase, exhaust valve 1110 phase, and the like are controlled.

  In the present embodiment, ECU 100 determines the phase of intake valve 1100 based on a map using engine speed NE and intake air amount KL as parameters, as shown in FIG. A plurality of maps for determining the phase of the intake valve 1100 are stored for each water temperature.

  Hereinafter, the intake VVT mechanism 2000 will be further described. Exhaust VVT mechanism 3000 may have the same configuration as intake VVT mechanism 2000 described below.

  As shown in FIG. 6, intake VVT mechanism 2000 includes sprocket 2010, cam plate 2020, link mechanism 2030, guide plate 2040, speed reducer 2050, and electric motor 2060.

  The sprocket 2010 is connected to the crankshaft 1090 via a chain or the like. The number of revolutions of the sprocket 2010 is one half of the number of revolutions of the crankshaft 1090. An intake camshaft 1120 is provided so as to be concentric with the rotation axis of the sprocket 2010 and to be rotatable relative to the sprocket 2010.

  Cam plate 2020 is connected to intake camshaft 1120 by pin (1) 2070. The cam plate 2020 rotates integrally with the intake camshaft 1120 inside the sprocket 2010. The cam plate 2020 and the intake camshaft 1120 may be formed integrally.

  The link mechanism 2030 includes an arm (1) 2031 and an arm (2) 2032. As shown in FIG. 7, which is a VII-VII cross section in FIG. 6, a pair of arms (1) 2031 are provided in the sprocket 2010 so as to be point-symmetric with respect to the rotation axis of the intake camshaft 1120. Each arm (1) 2031 is connected to the sprocket 2010 so as to be swingable around a pin (2) 2072.

  As shown in FIG. 8 which is a VIII-VIII cross section in FIG. 6 and FIG. 9 in which the phase of the intake valve 1100 is advanced from the state of FIG. 8, the arm (1) 2031 and the cam plate 2020 include: It is connected by an arm (2) 2032.

  The arm (2) 2032 is supported so as to be swingable with respect to the arm (1) 2031 about the pin (3) 2074. The arm (2) 2032 is supported so as to be swingable with respect to the cam plate 2020 around the pin (4) 2076.

  By the pair of link mechanisms 2030, the intake camshaft 1120 rotates relative to the sprocket 2010, and the phase of the intake valve 1100 is changed. Therefore, even if any one of the pair of link mechanisms 2030 is broken due to damage or the like, the phase of the intake valve 1100 can be changed by the other link mechanism.

  Returning to FIG. 6, a control pin 2034 is provided on the surface of each link mechanism 2030 (arm (2) 2032) on the guide plate 2040 side. The control pin 2034 is provided concentrically with the pin (3) 2074. Each control pin 2034 slides in a guide groove 2042 provided in the guide plate 2040.

  Each control pin 2034 is moved in the radial direction by sliding in the guide groove 2042 of the guide plate 2040. By moving each control pin 2034 in the radial direction, the intake camshaft 1120 is rotated relative to the sprocket 2010.

  As shown in FIG. 10 which is an XX section in FIG. 6, the guide groove 2042 is formed in a spiral shape so that each control pin 2034 is moved in the radial direction when the guide plate 2040 rotates. The shape of the guide groove 2042 is not limited to this.

  The more the control pin 2034 is radially away from the axis of the guide plate 2040, the more retarded the phase of the intake valve 1100 is. That is, the amount of change in phase becomes a value corresponding to the amount of operation of the link mechanism 2030 due to the control pin 2034 changing in the radial direction. Note that the phase of the intake valve 1100 may be further advanced as the control pin 2034 moves away from the axis of the guide plate 2040 in the radial direction.

  As shown in FIG. 10, when the control pin 2034 contacts the end of the guide groove 2042, the operation of the link mechanism 2030 is limited. Therefore, the phase at which the control pin 2034 contacts the end of the guide groove 2042 is the most retarded angle or the most advanced phase that is mechanically determined.

  Returning to FIG. 6, the guide plate 2040 is provided with a plurality of recesses 2044 for connecting the guide plate 2040 and the speed reducer 2050 on the surface on the speed reducer 2050 side.

  The reduction gear 2050 includes an external gear 2052 and an internal gear 2054. The external gear 2052 is fixed to the sprocket 2010 so as to rotate integrally with the sprocket 2010.

  The internal gear 2054 is formed with a plurality of convex portions 2056 that are received in the concave portions 2044 of the guide plate 2040. The internal gear 2054 is supported so as to be rotatable about an eccentric shaft 2066 of a coupling 2062 formed eccentrically with respect to the shaft center 2064 of the output shaft of the electric motor 2060.

  The XI-XI cross section in FIG. 6 is shown in FIG. The internal gear 2054 is provided such that some of the plurality of teeth mesh with the external gear 2052. When the output shaft rotational speed of the electric motor 2060 is the same as the rotational speed of the sprocket 2010, the coupling 2062 and the internal gear 2054 rotate at the same rotational speed as the external gear 2052 (sprocket 2010). In this case, the guide plate 2040 rotates at the same rotational speed as the sprocket 2010, and the phase of the intake valve 1100 is maintained.

  When the coupling 2062 is rotated relative to the external gear 2052 around the axis 2064 by the electric motor 2060, the entire internal gear 2054 rotates (revolves) around the axis 2064, The internal gear 2054 rotates around the eccentric shaft 2066. Due to the rotational movement of the internal gear 2054, the guide plate 2040 is rotated relative to the sprocket 2010, and the phase of the intake valve 1100 is changed.

  The phase of intake valve 1100 changes when the relative rotational speed between the output shaft of electric motor 2060 and sprocket 2010 (the amount of operation of electric motor 2060) is decelerated in reduction gear 2050, guide plate 2040, and link mechanism 2030. . The phase of intake valve 1100 may be changed by increasing the relative rotational speed between the output shaft of electric motor 2060 and sprocket 2010.

  As shown in FIG. 12, the overall reduction ratio of intake VVT mechanism 2000 (ratio of the relative rotational speed of output shaft of electric motor 2060 and sprocket 2010 to the amount of change in phase) is a value corresponding to the phase of intake valve 1100. Can take. In the present embodiment, the greater the reduction ratio, the smaller the amount of phase change with respect to the relative rotational speed between the output shaft of electric motor 2060 and sprocket 2010.

  When the phase of intake valve 1100 is in the retarded angle region from the most retarded angle to CA (1), the overall reduction ratio of intake VVT mechanism 2000 is R (1). When the phase of intake valve 1100 is in the advance region from CA (2) (CA (2) is the advance side of CA (1)) to the most advanced angle, the reduction ratio of intake VVT mechanism 2000 as a whole Is R (2) (R (1)> R (2)).

  When the phase of intake valve 1100 is in the intermediate region from CA (1) to CA (2), the reduction ratio of intake VVT mechanism 2000 as a whole is set to a predetermined rate of change ((R (2) −R (1)) / (CA (2) -CA (1))).

  Hereinafter, an operation of the intake VVT mechanism 2000 of the variable valve timing device will be described.

  When the phase of the intake valve 1100 (intake camshaft 1120) is advanced, when the electric motor 2060 is operated and the guide plate 2040 is rotated relative to the sprocket 2010, the intake valve 1100 is shown in FIG. The phase of is advanced.

  When the phase of intake valve 1100 is in the retarded region between the most retarded angle and CA (1), the relative rotational speed between the output shaft of electric motor 2060 and sprocket 2010 is decelerated by reduction ratio R (1). The phase of intake valve 1100 is advanced.

  When the phase of intake valve 1100 is in the advance angle region between CA (2) and the most advanced angle, the relative rotational speed between the output shaft of electric motor 2060 and sprocket 2010 is reduced by reduction ratio R (2). The phase of intake valve 1100 is advanced.

  When retarding the phase, the output shaft of the electric motor 2060 is rotated relative to the sprocket 2010 in the opposite direction to when the phase is advanced. When the phase is retarded, the relative rotational speed between the output shaft of the electric motor 2060 and the sprocket 2010 is the reduction ratio in the retardation region between the most retarded angle and CA (1), as in the case of the advance. The phase is delayed by R (1). In the advance angle region between CA (2) and the most advanced angle, the relative rotational speed between the output shaft of the electric motor 2060 and the sprocket 2010 is reduced by the reduction ratio R (2), and the phase is retarded. .

  As a result, as long as the relative rotation direction of the output shaft of the electric motor 2060 and the sprocket 2010 is the same, the retardation region between the most retarded angle and CA (1) and the most advanced angle CA (2) and The phase of intake valve 1100 can be advanced or retarded in both regions of the advance angle region between. At this time, the phase can be advanced or retarded more greatly in the advance angle region between CA (2) and the most advanced angle. Therefore, the phase can be changed in a large range.

  In addition, in the retardation region between the most retarded angle and CA (1), the reduction ratio is large, so that the output shaft of electric motor 2060 is controlled by the torque acting on intake camshaft 1120 as engine 1000 is operated. A large torque is required for rotation. Therefore, even when the electric motor 2060 is stopped or the like, even when the electric motor 2060 does not generate torque, the rotation of the output shaft of the electric motor 2060 due to the torque acting on the intake camshaft 1120 can be suppressed. it can. Therefore, it is possible to suppress the actual phase from changing from the control phase.

  By the way, when the phase of intake valve 1100 is in an intermediate region between CA (1) and CA (2), the output shaft of electric motor 2060 and sprocket 2010 are set at a reduction ratio that changes at a predetermined rate of change. The relative rotational speed of the intake valve 1100 is decelerated, and the phase of the intake valve 1100 is advanced or retarded.

  As a result, when the phase changes from the retard angle region to the advance angle region, or from the advance angle region to the retard angle region, the phase change amount with respect to the relative rotational speed between the output shaft of the electric motor 2060 and the sprocket 2010 is gradually increased or It can be gradually reduced. Therefore, it is possible to suppress the phase change amount from changing suddenly in steps, and to suppress the phase from changing suddenly. As a result, the phase controllability can be improved.

  Returning to FIG. 6, the electric motor 2060 is duty-controlled by the ECU 100 via an EDU (Electronic Driver Unit) 4000. Here, the duty control is to set a duty ratio indicating a rate at which a switching element (not shown) of the EDU 4000 is turned on, and by operating the switching element at this duty ratio, the operating voltage of the electric motor 2060 is set. It means to control.

  That is, the operating voltage of the electric motor 2060 is a voltage corresponding to the duty ratio. The greater the duty ratio, the higher the operating voltage. The higher the operating voltage, the greater the torque generated by the electric motor 2060. The electric motor 2060 generates a larger torque as the operating current is higher.

  A signal representing the duty ratio set by ECU 100 is output to EDU 4000. The EDU 4000 outputs a voltage corresponding to the duty ratio. Thereby, the electric motor 2060 is driven.

  Instead of setting the duty ratio, the operating voltage or operating current of the electric motor 2060 may be set directly. In this case, the electric motor 2060 may be driven by the set operating voltage or operating current.

  The rotational speed of the electric motor 2060 is a rotational speed corresponding to the torque generated by the electric motor 2060. The rotation speed of electric motor 2060 is detected by rotation speed sensor 5040, and a signal representing the detection result is transmitted to ECU 100.

  For example, the duty ratio is calculated (set) as the sum of the basic duty ratio and the correction duty ratio. The basic duty ratio and the correction duty ratio are determined by, for example, the target phase of intake valve 1100 determined using the map shown in FIG. 5 described above and the rotation speed of intake camshaft 1120 detected using cam position sensor 5010. And the phase (phase of intake valve 1100).

  More specifically, based on the difference ΔCA between the target phase and the detected phase, a required value of the rotational speed difference (relative rotational speed) between the output shaft of the electric motor 2060 and the sprocket 2010 (hereinafter referred to as the required rotational speed difference). Is also calculated). The required rotational speed difference is calculated using, for example, a map created in advance using ΔCA as a parameter. The method for calculating the required rotational speed difference is not limited to this.

  Further, a required value of the rotational speed of the output shaft of electric motor 2060 (hereinafter also referred to as required rotational speed) is calculated as the sum of the required rotational speed difference and the rotational speed of intake camshaft 1120.

  Based on the required rotational speed, the basic duty ratio of the electric motor 2060 is calculated. The basic duty ratio is calculated to a higher value as the required rotational speed is higher. The basic duty ratio is calculated using, for example, a map created in advance with the required rotational speed as a parameter. The method for calculating the basic duty ratio is not limited to this.

  The correction duty ratio is calculated based on the rotational speed difference ΔN between the output shaft rotational speed of the electric motor 2060 and the required rotational speed, which is detected using the rotational speed sensor 5040. The correction duty ratio is calculated as a value obtained by multiplying the rotation speed difference ΔN by the correction coefficient K. The method for calculating the correction duty ratio is not limited to this.

  The function of the ECU 100 will be described with reference to FIG. Note that the functions of the ECU 100 described below may be realized by hardware or software.

  ECU 100 includes a first phase control unit 110, a second phase control unit 120, a third phase control unit 130, and a learning unit 140. As shown in FIG. 15, the first phase control unit 110 is the most effective when the engine 1000 is driven (when fuel is injected and the engine 1000 outputs torque due to ignition). Intake VVT mechanism 2000 (electric motor 2060) is controlled so that the phase changes in the second range of the first range from the retarded phase to the most advanced phase. The second range does not include the most retarded phase.

  In the present embodiment, among the first range, the third range including the most retarded phase is used only when engine 1000 is started. This is because the most retarded phase is determined so that the phase of the intake valve 1100 is largely retarded in order to reduce the vibration at the start-up by reducing the compression ratio.

  When executing fuel cut to stop fuel injection in engine 1000, second phase control unit 120 controls intake VVT mechanism 2000 so that the phase is the most retarded phase that is mechanically determined. For example, the phase is retarded at a constant duty ratio until the phase change detected by the cam position sensor 5010 becomes “0”, so that the phase becomes the most retarded phase. The method for setting the phase to the most retarded phase is not limited to this.

  The third phase control unit 130 is the most retarded phase in which the phase is mechanically determined when the hybrid vehicle travels in the second travel mode using the driving force of only the MG (2) 400 with the engine 1000 stopped. The intake VVT mechanism 2000 is controlled so that

  Learning unit 140 learns the output value of cam position sensor 5010, that is, the phase detected by cam position sensor 5010 in a state where intake VVT mechanism 2000 is controlled so that the phase becomes the most retarded phase. .

  That is, the learning unit 140 detects the phase detected by the cam position sensor 5010 as the most retarded phase when the fuel cut is performed or when the hybrid vehicle travels using only the driving force of the MG (2) 400. To learn. For example, the initial value stored as the most retarded phase is replaced with the detected phase. Note that the deviation between the initial value and the detected phase may be learned. Further, the method of learning the phase is not limited to these.

  With reference to FIG. 16, a control structure of a program executed by ECU 100 as the control device according to the present embodiment will be described. Note that the program described below is repeatedly executed at a predetermined cycle.

  In step (hereinafter step is abbreviated as S) 100, ECU 100 determines whether engine 1000 is being driven or not. If engine 1000 is being driven (YES in S100), the process proceeds to S102. If not (NO in S100), the process proceeds to S110.

  In S102, ECU 100 controls intake VVT mechanism 2000 so that the phase changes in the second range not including the most retarded phase.

  In S110, ECU 100 determines whether or not to execute fuel cut. If the fuel cut is to be executed (YES in S110), the process proceeds to S114. If not (NO in S110), the process proceeds to S112.

  In S112, ECU 100 determines whether or not the hybrid vehicle travels in the second travel mode using only the driving force of MG (2) 400 while engine 1000 is stopped. If the vehicle travels in the second travel mode (YES in S112), the process proceeds to S114. Otherwise (NO in S112), this process ends.

  In S114, ECU 100 controls intake VVT mechanism 2000 so that the phase is the most retarded phase that is mechanically determined. In S116, ECU 100 learns the phase detected by cam position sensor 5010 as the most retarded phase.

  An operation of ECU 100 serving as the control device according to the present embodiment based on the structure and flowchart as described above will be described.

  In order to reduce the vibration at the time of starting by reducing the compression ratio, the phase of the most retarded angle is determined so that the phase of the intake valve 1100 is largely retarded. Therefore, when the phase is set to the most retarded phase while the engine 1000 is driven, the phase is retarded more than necessary. In this case, for example, the emission performance may be deteriorated. Further, a shock due to a decrease in the output of engine 1000 may occur.

  Therefore, when engine 1000 is being driven (YES in S100), intake VVT mechanism 2000 is controlled so that the phase changes in the second range not including the most retarded phase (S102).

  On the other hand, when the fuel cut is executed (YES in S110), or when the hybrid vehicle travels in the second travel mode using only the driving force of MG (2) 400 with engine 1000 stopped (YES in S112). ), That is, when engine 1000 is not driven, fuel is not burned in engine 1000. In these cases, even if the phase is set to the most retarded phase, it can be said that the emission performance does not deteriorate and no shock occurs.

  Therefore, intake VVT mechanism 2000 is controlled such that the phase is the most retarded phase that is mechanically determined (S114). In this state, the phase detected by the cam position sensor 5010 is learned as the most retarded phase (S116). Thereby, the phase of the most retarded angle can be learned without deteriorating the emission performance or generating a shock.

  As described above, according to the ECU that is the control device according to the present embodiment, when the engine is being driven, the intake VVT mechanism so that the phase changes in the second range not including the most retarded phase. Is controlled. When the engine is not driven, the intake VVT mechanism is controlled so that the phase becomes the most retarded phase. In this state, the phase detected by the cam position sensor is learned. Thereby, the phase of the most retarded angle can be learned without deteriorating the emission performance or generating a shock.

  Note that the phase detected by the cam position sensor may be learned at the mechanically determined most advanced phase.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic block diagram which shows the power train of a hybrid vehicle. It is an alignment chart of a power split mechanism. It is an alignment chart of a transmission. It is a schematic block diagram which shows the engine of a hybrid vehicle. It is a figure which shows the map which defined the phase of the intake valve. It is sectional drawing which shows the VVT mechanism for intake. It is VII-VII sectional drawing of FIG. It is VIII-VIII sectional drawing (the 1) of FIG. It is VIII-VIII sectional drawing (the 2) of FIG. It is XX sectional drawing of FIG. It is XI-XI sectional drawing of FIG. It is a figure which shows the reduction ratio as the whole VVT mechanism for intake. It is a figure which shows the relationship between the phase of the guide plate with respect to a sprocket, and the phase of an intake valve. It is a functional block diagram of ECU. It is a figure which shows the range from which a phase changes. It is a flowchart which shows the control structure of the program which ECU performs.

Explanation of symbols

  100 ECU, 102 ROM, 110 First phase control unit, 120 Second phase control unit, 130 Third phase control unit, 140 Learning unit, 200 MG (1), 300 Power split mechanism, 310 Sun gear (S), 320 Ring gear (R), 330 Carrier (C), 400 MG (2), 500 Transmission, 510 1st sun gear (S1), 520 2nd sun gear (S2), 531 1st pinion, 532 2nd pinion, 540 Ring gear (R), 550 carrier (C), 561 B1 brake, 562 B2 brake, 600 output shaft, 700 power storage device, 1000 engine, 1010 “A” bank, 1012 “B” bank, 1020 air cleaner, 1030 throttle valve, 1040 cylinder 1050 injector, 1060 ignition Plug, 1070 Three-way catalyst, 1090 Crankshaft, 1100 Intake valve, 1110 Exhaust valve, 1120 Intake camshaft, 1130 Exhaust camshaft, 2000 Intake VVT mechanism, 2010 Sprocket, 2020 Cam plate, 2030 Link mechanism, 2031 Arm (1 ), 2032 Arm (2), 2034 Control pin, 2040 Guide plate, 2042 Guide groove, 2044 Recess, 2050 Reducer, 2052 External gear, 2054 Internal gear, 2056 Convex, 2060 Electric motor, 2062 Coupling, 2064 Axis, 2066 Eccentric shaft, 2070 pin (1), 2072 pin (2), 2074 pin (3), 2076 pin (4), 3000 V for exhaust VT mechanism, 4000 EDU, 5000 crank angle sensor, 5010 cam position sensor, 5020 water temperature sensor, 5030 air flow meter, 5040 rotation speed sensor.

Claims (10)

A control device for a variable valve timing mechanism capable of changing a phase of at least one of an intake valve and an exhaust valve of an internal combustion engine within a first range from a first phase to a second phase,
Means for controlling the phase of the valve to change in a second range not including a third phase when the internal combustion engine is driven;
Control means for controlling the phase of the valve to be a third phase when the internal combustion engine is not driven;
Means for learning a phase detected by a detector for detecting the phase of the valve in a state where the phase of the valve is controlled to be the third phase. Control device.   The variable valve timing according to claim 1, wherein the control means includes means for controlling the valve phase to be the third phase when fuel injection in the internal combustion engine is stopped. Control device for the mechanism. The internal combustion engine operates in a first mode that travels using the driving force of the internal combustion engine and a second mode that travels using the driving force of a driving source different from the internal combustion engine when the internal combustion engine is stopped. Mounted on selectable vehicles,
2. The variable valve timing according to claim 1, wherein the control means includes means for controlling the phase of the valve to be the third phase when the vehicle travels in the second mode. Control device for the mechanism.   The control device for a variable valve timing mechanism according to any one of claims 1 to 3, wherein the third phase is a phase of the most retarded angle in the first range. A control method of a variable valve timing mechanism capable of changing a phase of at least one of an intake valve and an exhaust valve of an internal combustion engine within a first range from a first phase to a second phase,
A step of controlling the phase of the valve to change in a second range not including a third phase when the internal combustion engine is driven;
Controlling the phase of the valve to be a third phase when the internal combustion engine is not driven;
Learning a phase detected by a detector for detecting the phase of the valve in a state where the phase of the valve is controlled to be the third phase. .   The step of controlling the phase of the valve to be the third phase is a step of controlling the phase of the valve to be the third phase when fuel injection in the internal combustion engine is stopped. The method for controlling a variable valve timing mechanism according to claim 5, comprising: The internal combustion engine operates in a first mode that travels using the driving force of the internal combustion engine and a second mode that travels using the driving force of a driving source different from the internal combustion engine when the internal combustion engine is stopped. Mounted on selectable vehicles,
The step of controlling the phase of the valve to be the third phase is a step of controlling the phase of the valve to be the third phase when the vehicle travels in the second mode. The method for controlling the variable valve timing mechanism according to claim 5, comprising:   The control method for a variable valve timing mechanism according to claim 5, wherein the third phase is a phase of the most retarded angle in the first range.   The program which makes a computer implement | achieve the control method in any one of Claims 5-8.   The computer-readable recording medium which recorded the program which makes a computer implement | achieve the control method in any one of Claims 5-8.

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