JP2010120582A - Controller for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly efficiently operate an internal combustion engine as much as possible in a range hardly causing reduction of drivability in changing valve timing. <P>SOLUTION: In the hybrid vehicle 10 capable of changing the valve timing of an intake valve 207, an ECU 100 performs control for switching a second operation line. In the control, when the valve timing changes an advance-side valve timing to a delay-side valve timing, the ECU 100 calculates an engine rotation speed deviation ΔNE as a deviation between a reference engine rotation speed NEbase and a target engine rotation speed NEtag. When the calculated ΔNE is not less than a threshold value (A), the ECU 100, with the assumption that the variation of the engine rotation speed accompanying switch of the operation line is regarded as giving less influences on the drivability, sets operation line switching time Tm accompanying the change of the valve timing to Tm1 that is shorter than switching time Tm2 when the ΔNE is less than the threshold value (A). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a technical field of a control device for a hybrid vehicle including a variable valve operating device such as a VVT (Variable Valve Timing).

  As this type of device, a device that changes the ignition start rotational speed of the engine in accordance with the temperature of hydraulic oil that drives the variable valve operating device has been proposed (see, for example, Patent Document 1). According to the power output device disclosed in Patent Document 1 (hereinafter referred to as “conventional technology”), when the hydraulic oil is in a high temperature state where the viscosity of the hydraulic oil is low, By setting the engine ignition start speed to a higher value, the lock pin of the variable valve timing mechanism can be reliably removed from the locking hole, and the valve timing after engine startup can be changed smoothly. It is supposed to be.

  A technique for correcting the control target value of the variable valve mechanism according to the deviation between the actual intake air amount and the target intake air amount has also been proposed (see, for example, Patent Document 2).

JP 2007-153212 A JP 2007-126969 A

  Some hybrid vehicles can freely control internal combustion engine operating lines (characteristic lines that define internal combustion engine control conditions, which are defined by individual operating points), although there are practical restrictions. There is something. In this type of hybrid vehicle, when the valve timing of the intake valve is changed, the internal combustion engine can be operated as efficiently as possible by switching the operation line according to the changed valve timing. It is. On the other hand, since switching of the operation line is accompanied by fluctuations in the engine rotation speed, when switching the operation lines in consideration of only efficiency, for example, fluctuations in the engine rotation speed are manifested as drivability deterioration. there is a possibility. On the other hand, if this type of drivability decline is disliked and the operating line is switched slowly, the thermal efficiency of the internal combustion engine and inefficient power consumption will occur during the switching of the operating line, resulting in the system efficiency of the hybrid vehicle. May decrease. That is, the conventional technique has a technical problem that it is difficult to switch the operation line while achieving both drivability and system efficiency when the valve timing is changed.

  The present invention has been made in view of the above-described problems, and provides a control device for a hybrid vehicle capable of operating an internal combustion engine as efficiently as possible without causing a drop in drivability when changing valve timing. The task is to do.

  In order to solve the above-described problem, a control apparatus for a hybrid vehicle according to the present invention includes an internal combustion engine having a variable valve device capable of changing a valve opening timing of an intake valve as a power source, and at least one electric motor. And a power distribution means including a plurality of rotating elements that are differentially rotatable with respect to each other, each including a rotating element coupled to an engine output shaft of the internal combustion engine and an output shaft of the at least one electric motor. A control device for a hybrid vehicle configured to be able to switch an operation line of the internal combustion engine by a differential action of the plurality of rotating elements in the power distribution means, wherein the operation line is switched according to the valve opening timing. The deviation between the switching means, the reference value of the engine speed of the internal combustion engine based on the required output of the hybrid vehicle, and the target value of the engine speed is specified. Specifying means that, when the valve opening timing is changed to the retard side, characterized by a control means for controlling the switching time of the operation line in response to the identified deviation.

  A hybrid vehicle according to the present invention includes an internal combustion engine as a power source and at least one electric motor, and a plurality of rotating elements each connected to an output shaft thereof, for example, a planetary gear mechanism or a complex planetary planet. Power distribution means that can take the form of a gear mechanism or the like is provided, and in particular, the operation line of the internal combustion engine can be switched in a binary, stepwise or continuous manner. The “operation line” is an operation as one operating condition of the internal combustion engine that is defined on a coordinate plane in which parameters correlated with the output of the internal combustion engine, such as the engine speed and torque, are arranged on each axis. It means a characteristic line that defines control conditions for an internal combustion engine, obtained by connecting points for each required output of the internal combustion engine, for example. For example, one operation point on the operation line selected at that time corresponds to one required output of the internal combustion engine.

  Here, such an action line switching action is obtained by a differential action between the rotating elements in the power distribution means. In other words, the power distribution means is configured so that the operation line of the internal combustion engine can be freely switched (including being free within a range of physical, mechanical, or electrical restrictions). The structure is defined. For example, when the power distribution means is configured as a planetary gear mechanism having a sun gear, a carrier, and a ring gear as rotating elements, for example, the sun gear is used as an electric motor, the carrier is used as an engine output shaft of an internal combustion engine, and the ring gear is used as an axle. If the motor is connected to another motor, the rotational speed of the ring gear is unambiguous with the vehicle speed. Therefore, the engine rotational speed of the internal combustion engine can be controlled to increase or decrease by controlling the rotational speed of the motor. It becomes possible. That is, it becomes possible to freely select the operating point of the internal combustion engine, and inevitably the operating line can also be freely selected. At this time, if the excess and deficiency of the power to be output to the axle is compensated by the input / output of the power between the other electric motor and the axle, the operating point of the internal combustion engine can be widened while satisfying the required output of the entire hybrid vehicle. It may be possible to select freely. For example, in such a case, the operating point of the internal combustion engine is set to a so-called optimum fuel consumption operating point at which the thermal efficiency is theoretically or practically maximized (that is, the fuel consumption rate is minimized) as a preferred embodiment. Also good.

  On the other hand, in the internal combustion engine according to the present invention, a physical, mechanical, electrical or magnetic mechanism, apparatus and system capable of changing the valve opening timing of the intake valve (necessarily changing the valve timing). For example, a variable valve operating device such as VVT (Variable Valve Timing) is provided. At this time, as long as the opening timing of the intake valve is variable, the lift amount or operating angle of the intake valve may be variable, or instead of or in addition, the opening timing and lift of the exhaust valve may be variable. The amount or working angle may be variable. The valve opening timing of the intake valve is the valve overlap amount (the length of the period during which both the intake and exhaust valves are open (preferably the crank angle), particularly when the valve opening timing of the exhaust valve is fixed. It is an index that defines the angle concept)). The valve overlap amount correlates with the amount of intake air that is the amount of air or air-fuel mixture sucked into the cylinder, and qualitatively, the valve overlap amount is reduced in the low rotation region, thereby suppressing internal EGR. As a result, the valve overlap amount is increased in the high speed region, and the intake efficiency is improved by the effect of promoting the introduction of the intake air due to the exhaust inertia.

  Here, in view of the fact that the magnitude of the valve overlap amount affects the magnitude of the intake air amount, the optimum operating point to be taken by the internal combustion engine (i.e., uniquely optimum) according to the opening timing of the intake valve. The operating line) can vary. More specifically, if the valve opening timing of the intake valve is binary switched between a retarded value and an advanced value, the valve opening timing is advanced in a high rotation range. If the upper limit value of torque is increased by increasing the intake air amount by setting the value on the side, generally the thermal efficiency of the internal combustion engine will improve on the high torque side, so the operating point on the lower rotation high torque side will be selected There can be rational reasons to be done. Even if this kind of general theory is not applied, if there is no correlation between the opening timing of the intake valve and the optimum operating point of the internal combustion engine, the change of the opening timing is substantially meaningless. It is clear that the operation line needs to be changed.

  Therefore, according to the control apparatus for a hybrid vehicle according to the present invention, during its operation, it is configured as various processing units such as an ECU (Electronic Control Unit), various controllers or various computer systems such as a microcomputer device, or the like. The operating means of the internal combustion engine is switched by the switching means according to the opening timing of the intake valve. The mode of switching the operation line according to the opening timing of the intake valve is not particularly limited. However, as described above, as described above, the thermal efficiency of the internal combustion engine at that time is within the range of theoretical or practical constraints. The operating line is switched so that the optimal operating point is selected.

  On the other hand, the switching of the operating line may be accompanied by a fluctuation in the engine speed of the internal combustion engine (hereinafter referred to as “rotational fluctuation” as appropriate), although the rotational fluctuation from the low rotation side to the high rotation side is particularly large. It can be easily perceived by the driver as a so-called blow-up feeling, which can be a factor that reduces drivability. Further, in view of the point that the intake air amount can be increased when the opening timing of the intake valve is set on the advance side (that is, high torque can be easily obtained and the operating point is easily set on the low rotation side), The fluctuation in rotation from the low rotation side to the high rotation side that can lead to a feeling of blow-up can occur when the valve opening timing of the intake valve is changed to the retard side (for example, the valve opening timing is a reference value and an advance side value). In a configuration in which binary switching between the two is performed, for example, when the advance angle request is turned off. Therefore, it is difficult to reliably suppress a decrease in drivability within the scope of the technical idea of switching the operation line without paying attention to this type of rotational fluctuation.

  Therefore, according to the control apparatus for a hybrid vehicle according to the present invention, at the time of its operation, for example, a reference means for engine rotational speed is provided by specific means configured as various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. The deviation between the value and the target value is specified. Further, when the control means configured as various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device, the opening timing of the intake valve changes to the retard side, the specified deviation is The operation line switching time is controlled accordingly.

  The reference value of the engine rotational speed is a required output of the internal combustion engine determined based on, for example, the vehicle speed and the accelerator opening (that is, unambiguous with the required load) on the operation line to be referred to (internal combustion engine) Is the engine rotational speed at the operating point corresponding to the hybrid vehicle's required output), which is a transient control target value, preferably theoretically indicating the thermal efficiency of the internal combustion engine. Or, it is the engine speed that can be maximized within the range of realistic constraints.

  On the other hand, the target value of the engine rotational speed is a target value that is finally set when the engine rotational speed follows the reference value as such a transient control target value. Restrictions on the operation of various parts and members constituting the engine and the hybrid vehicle, or various electric and mechanical systems (physical, mechanical, electrical or control operating limits, or preset specifications and control (Including restrictions), the engine speed increases at a constant or indefinite ratio with respect to the reference value. Therefore, this deviation is such that the amount of change in the engine rotational speed per time is smaller and larger as it is larger, such as in a steady traveling state (for example, traveling on a flat road at a constant speed). Have. In the steady state, this target value can converge to the reference value.

  Here, the operation line switching time may be expressed as the operation line switching speed if the reference value of the engine rotational speed before and after the operation line switching is constant, and is an element that defines at least the operation line switching speed. Thus, the degree of rotational fluctuation at the time of switching the operating line can be defined, but the sensitivity of drivability to the degree of rotational fluctuation is affected by the change state of the engine rotational speed before switching of the operating line.

  More specifically, even if the switching speed of the operation line is constant, the influence on the drivability is small in the area where the change in the engine rotation speed is originally large, and the drivability is given in the area where the change in the engine rotation speed is small. The impact will be greater. Therefore, as long as drivability is not reduced by controlling the operation line switching time according to the deviation between the reference value and the target value, which correlates with the amount of change in the engine speed before the operation line switching. Therefore, the target value can be converged to the reference value at an early stage, and the internal combustion engine can be operated at an appropriate operating point. In other words, the internal combustion engine can be operated as efficiently as possible without causing a decrease in drivability.

  Note that “specific” according to the present invention refers to a specific target (in the present invention, a deviation between a reference value and a target value) or a physical quantity, control amount, or index value correlated with the specific target via a predetermined detection means. Directly or indirectly detected, stored in advance in appropriate storage means based on physical quantity, control amount or index value correlated with specific object detected directly or indirectly via the detection means Selecting a corresponding value from a map, etc., deriving from a physical quantity, control quantity or index value or a selected value correlated with this type of specific target, or in accordance with a preset algorithm or calculation formula, or this Thus, it is a broad concept encompassing simply acquiring the value detected, selected or derived in the form of an electric signal, for example. In the range of the concept, the specifying unit may specify the deviation in any way.

  In one aspect of the control apparatus for a hybrid vehicle according to the present invention, the control means is configured such that when the specified deviation is greater than or equal to a predetermined value, the switching time is greater than when the deviation is less than the predetermined value. To shorten.

  According to this aspect, the specified deviation is equal to or greater than a predetermined value (“more than” is a concept that can be easily replaced with “greater” depending on the setting of the reference value, and the reference value is in any region. If it belongs to a design matter and does not affect the essence of the invention, the operation line switching time is shortened. That is, the switching speed is increased. Therefore, it is possible to enjoy the practical benefits according to the present invention relatively easily without reducing the essential part.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

<Embodiment of the Invention>
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<Configuration of Embodiment>
First, the configuration of a hybrid vehicle 10 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram conceptually showing the configuration of the hybrid vehicle 10.

  In FIG. 1, the hybrid vehicle 10 includes an ECU 100, a PCU (Power Control Unit) 11, a battery 12, a vehicle speed sensor 13, an accelerator opening sensor 14, and a hybrid drive device 1000 according to the present invention. It is.

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM, and the like, and is configured to be able to control the operation of each part of the hybrid vehicle 10. It is an example of a “control device for a hybrid vehicle”. The ECU 100 is configured to be able to execute first and second operation line switching control described later according to a control program stored in the ROM. The ECU 100 is an integrated electronic control unit configured to function as an example of each of the “switching unit”, “specifying unit”, and “control unit” according to the present invention. All are configured to be executed by the ECU 100. However, the physical, mechanical, and electrical configurations of each of the units according to the present invention are not limited to this. For example, each of these units includes a plurality of ECUs, various processing units, various controllers, a microcomputer device, and the like. It may be configured as various computer systems.

  The PCU 11 converts the DC power extracted from the battery 12 into AC power and supplies it to a motor generator MG1 and a motor generator MG2, which will be described later, and also converts AC power generated by the motor generator MG1 and the motor generator MG2 into DC power. Inverter (not shown) configured to be supplied to the battery 12, and the power input / output between the battery 12 and each motor generator, or the power input / output between the motor generators (that is, In this case, the control unit is configured to be capable of controlling power transfer between the motor generators without using the battery 12. The PCU 11 is electrically connected to the ECU 100, and its operation is controlled by the ECU 100.

  The battery 12 is a rechargeable power storage unit configured to be able to function as a power supply source related to power for powering the motor generator MG1 and the motor generator MG2.

  The vehicle speed sensor 13 is a sensor configured to be able to detect the vehicle speed V of the hybrid vehicle 10. The vehicle speed sensor 13 is electrically connected to the ECU 100, and the detected vehicle speed V is referred to by the ECU 100 at a constant or indefinite period.

  The accelerator opening sensor 14 is a sensor configured to be able to detect an accelerator opening Ta that is an operation amount of an accelerator pedal (not shown) of the hybrid vehicle 10. The accelerator opening sensor 14 is electrically connected to the ECU 100, and the detected accelerator opening Ta is referred to by the ECU 100 at a constant or indefinite period.

  The hybrid drive device 1000 is a power unit that functions as a power train of the hybrid vehicle 10. Here, a detailed configuration of the hybrid drive apparatus 1000 will be described with reference to FIG. FIG. 2 is a schematic configuration diagram conceptually showing the configuration of the hybrid drive apparatus 1000. In the figure, the same reference numerals are given to the same portions as those in FIG. 1, and the description thereof will be omitted as appropriate.

  In FIG. 2, a hybrid drive apparatus 1000 includes an engine 200, a power split mechanism 300, a motor generator MG1 (hereinafter appropriately referred to as “MG1”), a motor generator MG2 (hereinafter appropriately referred to as “MG2”), and a speed reduction mechanism. 400.

  The engine 200 is a gasoline engine which is an example of the “internal combustion engine” according to the present invention, and is configured to function as a main power source of the hybrid vehicle 10. Here, the detailed configuration of the engine 200 will be described with reference to FIG. FIG. 3 is a schematic view illustrating a one-plane configuration of the engine 200. In the figure, the same reference numerals are given to the same portions as those in FIGS. 1 and 2, and the description thereof is omitted as appropriate. The “internal combustion engine” in the present invention includes, for example, a two-cycle or four-cycle reciprocating engine, and has at least one cylinder. In the combustion chamber inside the cylinder, various types such as gasoline, light oil, alcohol, etc. An engine configured to be able to take out the force generated when the air-fuel mixture containing fuel burns as a driving force through appropriate physical or mechanical transmission means such as a piston, a connecting rod, and a crankshaft. It is a comprehensive concept. As long as the concept is satisfied, the configuration of the internal combustion engine according to the present invention is not limited to that of the engine 200 and may have various aspects.

  The engine 200 is an in-line four-cylinder engine in which four cylinders 201 are arranged in series in a cylinder block. The engine 200 is configured to be able to convert a reciprocating motion of a piston (not shown) generated when a mixture of air and fuel is combusted inside each cylinder into a rotating motion via a connecting rod and a crankshaft (both not shown). Has been. The rotational position of the crankshaft is detected by a crank position sensor (not shown) that is electrically connected to the ECU 100, and is referred to by the ECU 100 at a constant or indefinite period via a predetermined control bus. In addition, it is configured to be used for various operation control of the injector and the injector.

  When the engine 200 operates, the air sucked from the outside is guided to the intake pipe 202 and purified by the air cleaner 203, and then supplied to the intake manifold 202a communicating with each cylinder. Further, the intake air amount related to the intake air is detected by an air flow meter 204 located downstream of the air cleaner 203. The air flow meter 204 is electrically connected to the ECU 100, and the intake air amount detected by the air flow meter 204 is referred to by the ECU 100 at a constant or indefinite period.

  A throttle valve 205 is provided in the intake pipe 202, and the intake air amount supplied to the intake manifold 202a is controlled according to the opening degree. The throttle valve 205 is an electronically controlled throttle valve that is driven by an electric actuator such as a throttle valve motor (not shown). The throttle valve 205 is electrically connected to the ECU 100, and the ECU 100 opens, for example, an accelerator pedal (not shown). Accordingly, the opening degree is controlled irrespective of the opening degree of the accelerator pedal. The throttle opening, which is the opening of the throttle valve 205, is detected by a throttle opening sensor 206 provided in the vicinity of the throttle valve 205. The throttle opening sensor 206 is electrically connected to the ECU 100, and the detected throttle opening is referred to by the ECU 100 at a constant or indefinite period.

  The combustion chamber in the cylinder 201 is injected and supplied from, for example, an electronically controlled injector (not shown) or the like in air supplied via the intake manifold 202a and an intake port (not shown) communicating with the intake manifold 202a. The fuel / air mixture is sucked through the two intake valves 207. At this time, the air-fuel mixture is supplied into the combustion chamber when the intake valve 207 is opened. The fuel supply system such as the injector is electrically connected to the ECU 100, and the ECU 100 controls the injection amount and the injection timing (injection crank angle).

  In the combustion chamber, the air-fuel mixture burns by the ignition operation by the spark plug 208 in the combustion stroke. The spark plug 208 is electrically connected to the ECU 100 (a control line is not shown), and the ECU 100 is configured to control its ignition timing (ignition crank angle). The air-fuel mixture that has been burned in the combustion chamber is discharged to the exhaust port as exhaust gas when the two exhaust valves 209 communicating with an exhaust port (not shown) are opened. The exhaust is discharged through an exhaust manifold 210a and an exhaust pipe 210 communicating with the exhaust port.

  The exhaust pipe 210 is provided with a three-way catalyst 211, and the exhaust gas discharged to the exhaust pipe 210 is purified by the three-way catalyst 211 and further sequentially purified by other catalyst devices installed in the subsequent stage. It is configured to be discharged outside the vehicle after being sent. Cooling water is circulated and supplied to the water jacket accommodated in the cylinder block of the engine 200, and the cooling water temperature Tw, which is the temperature of the cooling water, is detected by the water temperature sensor 233 and electrically connected to the water temperature sensor 233. It is configured to be constantly grasped by the ECU 100 connected to the.

  The opening / closing operation of the intake valve 207 is controlled by an intake cam 213 fixed in association with each intake valve 207 on an intake cam shaft 212 rotatably supported on a cylinder head (not shown). On the other hand, the opening / closing operation of the exhaust valve 209 is controlled by an exhaust cam 215 fixed in association with each exhaust valve 209 on an exhaust cam shaft 214 rotatably supported on a cylinder head (not shown). Here, in this embodiment, in particular, a VVT controller 216 is provided near one end of the intake camshaft 212, and the valve timing of the intake valve 207 is variably controlled.

  Here, the configuration of the VVT controller 216 will be described with reference to FIG. FIG. 4 is a schematic cross-sectional view of the VVT controller 216 on a plane orthogonal to the intake camshaft 212.

  In FIG. 4, the VVT controller 216 includes a housing 217 and a rotor 218.

  The housing 217 is fixed by being fastened with a bolt or the like to a sprocket (not shown) rotatably supported on the outer periphery of the intake camshaft 212 extending in a direction perpendicular to the paper surface. At this time, the rotation of the crankshaft in the engine 200 is transmitted to the sprocket and the housing 217 via a timing chain (not shown), so the sprocket and the housing 214 can rotate in synchronization with the crankshaft. .

  The intake camshaft 212 is rotatably supported by the cylinder head of the engine 200 and a bearing cap. The rotor 218 is fixed by being tightened with a bolt via a stopper at one end of the intake camshaft 212 supported in this manner, and is housed in the housing 217 so as to be rotatable. In addition, a plurality of liquid chambers are formed inside the housing 217, and each of them is partitioned into an advance chamber 220 and a retard chamber 221 by a vane 219 formed on the outer periphery of the rotor 218. . Note that a lock hole 223 is formed in one of the plurality of vanes 219 formed in the rotor 218. The operation of the lock hole 223 will be described later.

  A retard side channel portion 222 is formed in an annular shape on the outer peripheral portion of the intake camshaft 212, and communicates with each of the retard chambers 221 via a hydraulic channel (not shown). Further, an advance side channel portion (not shown) is formed in an annular shape on the outer periphery of the intake camshaft 212 in the same manner as the retard side channel portion 222 and is not shown in each advance chamber 220. It communicates via the hydraulic flow path.

  On the other hand, the VVT controller 216 includes a hydraulic pressure transmission system 225 including hydraulic pressure channels such as the retard side channel portion 222 and the advance side channel portion described above. Here, the hydraulic pressure transmission system 225 will be described with reference to FIG. FIG. 5 is a schematic diagram of the hydraulic pressure transmission system 225.

  In FIG. 5, the hydraulic pressure transmission system 225 includes a hydraulic pressure control valve 226 driven by a spring 227 and a solenoid 228. The hydraulic pressure control valve 226 moves the valve body into an advanced position where the hydraulic pressure is transmitted to the advance chamber 220, a retard position where the hydraulic pressure is transmitted to the retard chamber 221 and the advance chamber 220 and the retard chamber. 221 is configured to be switchable to any of the non-transmission positions where the hydraulic pressure is not transmitted to any of them. The solenoid 228 is electrically connected to the ECU 100 via a drive system (not shown), and the position of the valve body of the hydraulic pressure control valve 226 is switched according to the solenoid current controlled by the upper control of the ECU 100. It is configured to be possible.

  The spring 227 is an elastic member that urges the hydraulic pressure control valve 226 in the right direction in the figure. When no current is supplied to the solenoid 228, the hydraulic pressure control valve 226 is configured to stop at the retarded position as shown in the figure by being biased by the spring 227.

  The hydraulic pressure transmission system 225 includes a pump 229. The pump 229 is configured to be operated by the power of the engine 200, and is configured to be able to pump a part of lubricating oil in the engine 200 from the oil pan 230 and circulate and supply it to each part of the VVT controller 216. Has been. The oil circulated and supplied by the pump 229 passes through the retard side delivery 231 and the advance side delivery 232 connected to the hydraulic pressure control valve 226, and further communicates with the retard side channel portion 222 described above. In other words, it is finally supplied to the retard chamber 221 and the advance chamber 220 through the advance side flow path section or the like.

  Returning to FIG. 2, the motor generator MG1 is a motor generator that is an example of the “motor” according to the present invention, and has a power running function that converts electrical energy into kinetic energy and a regeneration function that converts kinetic energy into electrical energy. It has a configuration with. The motor generator MG2 is a motor generator that is another example of the “motor” according to the present invention. Like the motor generator MG1, the motor generator MG2 converts a power running function that converts electrical energy into kinetic energy, and converts kinetic energy into electrical energy. It has a configuration with a regenerative function. Motor generators MG1 and MG2 are configured as, for example, synchronous motor generators, and include, for example, a rotor having a plurality of permanent magnets on an outer peripheral surface, and a stator wound with a three-phase coil that forms a rotating magnetic field. It may have, and may have other composition.

  The power split mechanism 300 includes a sun gear 303 as an example of a “rotating element” according to the present invention provided at the center, and a “rotating element” according to the present invention provided concentrically around the outer periphery of the sun gear 303. A ring gear 301 as an example, a plurality of pinion gears 305 that are arranged between the sun gear 303 and the ring gear 301 and revolve around the outer periphery of the sun gear 303, and support the rotation shafts of these pinion gears. It is a planetary gear mechanism as an example of “power distribution means” according to the present invention, which includes a planetary carrier 306 as yet another example of the “rotating element” according to the present invention.

  Here, the sun gear 303 is coupled to the rotor (not shown) of the MG1 via the sun gear shaft 304, and the rotation speed thereof is equivalent to the rotation speed Nmg1 of the MG1. The ring gear 301 is coupled to a rotor (not shown) of MG2 via a drive shaft 302 and a speed reduction mechanism 500, and the rotation speed thereof is equivalent to the rotation speed Nmg2 of MG2. Further, the planetary carrier 306 is coupled to the crankshaft of the engine 200, and the rotation speed thereof is equivalent to the engine rotation speed NE of the engine 200.

  On the other hand, the drive shaft 302 is connected to drive shafts SFR and SFL that respectively drive the right front wheel FR and the left front wheel FL, which are drive wheels of the hybrid vehicle, and a reduction mechanism 500 as a reduction device including various reduction gears such as a differential. ing. Therefore, the motor torque output from the motor generator MG2 to the drive shaft 302 is transmitted to each drive shaft via the speed reduction mechanism 500, and similarly, the drive force from each drive wheel transmitted via each drive shaft is Then, it is input to the motor generator MG2 via the speed reduction mechanism 500 and the drive shaft 302. That is, the rotational speed Nmg2 of the motor generator MG2 is uniquely related to the vehicle speed V of the hybrid vehicle 10.

  Under such a configuration, the power split mechanism 300 transmits power generated by the engine 200 to the sun gear 303 and the ring gear 301 by the planetary carrier 306 and the pinion gear 305 (a ratio corresponding to the gear ratio between the gears). And the power of the engine 200 can be divided into two systems.

  The configuration of the embodiment relating to the “power distribution means” according to the present invention is not limited to that of the power split mechanism 300. For example, the power distribution means according to the present invention includes a plurality of planetary gear mechanisms, and a plurality of rotating elements provided in one planetary gear mechanism are appropriately connected to each of a plurality of rotating elements provided in another planetary gear mechanism, An integral differential mechanism may be configured. In addition, the speed reduction mechanism 500 according to the present embodiment merely reduces the rotational speed of the drive shaft 302 in accordance with a preset reduction ratio, but the hybrid vehicle 10 includes, for example, a plurality of speed reduction devices separately from this type of speed reduction device. A stepped transmission device including a plurality of shift speeds including the clutch mechanism and the brake mechanism as a component may be provided.

<Operation of Embodiment>
<Valve timing control>
The drive state of the VVT controller 216 is controlled according to three types of control modes described below. <Forced most retarded angle mode>
The forced maximum retardation mode is executed for a period during which the engine 200 is in the engine stopped state or a period after the engine is started. When the hydraulic pressure of the oil supplied to the VVT controller 216 decreases as the engine 200 stops, the vane 219 gradually rotates to the retard side due to the friction of the movable part, and finally the most retarded position. (Ie, the position corresponding to the most retarded side in the movable range of the vane 219). In the forced most retarded mode, the position of the vane 219 is forcibly fixed at the most retarded position. More specifically, a lock pin (not shown) is installed in a portion corresponding to the most retarded angle position of the vane 219 in which the lock hole 223 is formed so as to be able to protrude and retract with respect to the lock hole 223. This lock pin is normally biased in the direction of the lock hole 223 by a coil spring (not shown), and has a predetermined release hydraulic pressure (higher than the hydraulic pressure required to rotate the vane 219) in the lock hole 223. When the oil is supplied at the above hydraulic pressure and the hydraulic pressure overcomes the bias by the coil spring, it is accommodated in a predetermined accommodation hole that does not hinder the rotation of the vane 219. Accordingly, when the vane 219 stops at the most retarded position as the hydraulic pressure decreases while the engine is stopped, the lock pin 224 is fitted into the lock hole 223 by the biasing force of the coil spring, and the rotation of the vane 219 is mechanical. Fixed or locked.

<Feedback mode>
If the hydraulic pressure applied to the lock hole 223 becomes equal to or higher than the above-described release hydraulic pressure in the process in which the hydraulic pressure increases with the start of the engine 200, the forced maximum retardation mode is released and the vane 219 rotates in its movable range. It becomes movable. In this state, when the hydraulic pressure in the advance chamber 220 and the retard chamber 221 is changed, the vane 219 rotates in the illustrated advance direction and the retard direction in accordance with the degree of both of the fluid pressures within a predetermined movable range. Move. At this time, since the rotor 218 in which the vane 219 is formed also rotates with the vane 219, as a result, the rotational phase of the intake camshaft 212 changes with respect to the rotational phase of the crankshaft, that is, the intake camshaft 212. The rotational phase difference with respect to the crankshaft changes, and the valve timing of the intake valve 207 fixed to the intake camshaft 212 changes. At this time, the ECU 100 calculates the target displacement angle of the valve timing of the intake valve 207 and supplies the signal corresponding to the feedback current value to the drive system that drives the solenoid 228 to control the solenoid 228. As a result, in the F / B mode, the rotational phase difference of the intake camshaft 212 converges to a desired value in a feedback manner.

<Retention mode>
On the other hand, when the valve body of the hydraulic pressure control valve 226 is controlled to the non-transmission position in a state where appropriate hydraulic pressure is applied to the advance chamber 220 and the retard chamber 221 via the hydraulic pressure transmission system 225, the holding mode is set. Operates. In the holding mode, since the hydraulic pressure in the advance chamber 220 and the retard chamber 221 is maintained, the vane 219 is fixed by the hydraulic pressure in both the advance chamber 220 and the retard chamber 221 and the housing 217 accompanying the rotation of the crankshaft. Is transmitted to the rotor 218 and the vane 219 via oil. Therefore, the intake camshaft 212 fixed to the rotor 218 is rotationally driven integrally with the rotor 218 while maintaining a constant rotational phase difference with the crankshaft. In the hybrid vehicle 10, basically, the feedback mode and the holding mode are appropriately executed during the period in which the engine 200 is operating, and the valve timing of the intake valve 207 is maintained at the target value.

  Here, in the present embodiment, the valve timing of the intake valve 207 includes an advance side valve timing corresponding to a state in which the vane 219 stops at a predetermined advance position, and a vane 219 at a predetermined retard position (the above-mentioned maximum angle position). It is assumed that it is possible to switch binaryly between the retarded side valve timing corresponding to the state stopped at the advanced angle side with respect to the retarded position. At this time, the ECU 100 refers to a preset valve timing map and selects one of the advance side valve timing and the retard side valve timing that matches the operating condition of the hybrid vehicle 10 as the target valve timing. This valve timing map is constructed as a map using the accelerator opening Ta (required load) of the hybrid vehicle 10 and the vehicle speed V as parameters. That is, a configuration in which one of the valve timings is associated with each combination of the accelerator opening degree Ta and the vehicle speed V is adopted. Qualitatively, the advance side valve timing is selected in a region where the accelerator opening degree Ta is large (that is, the high load region), and the retard side valve timing is selected in other regions. The valve timing control of the intake valve 207 according to the present embodiment is an example, and the valve timing of the intake valve 207 may be variably controlled, for example, in multiple stages or continuously.

<Control of operation line>
In the hybrid vehicle 10 according to the present embodiment, a gear ratio that is a ratio between the rotational speed of the crankshaft of the engine 200 and the rotational speed of the drive shaft 302 can be freely selected. Here, with reference to FIG. 6, the mechanism of the control of the gear ratio will be described. FIG. 6 is an operation alignment chart for explaining the operation state of each part of the hybrid drive apparatus 1000. In the figure, the same reference numerals are given to the same portions as those in FIG. 2, and the description thereof will be omitted as appropriate.

  In FIG. 6, the vertical axis represents the rotational speed, and the horizontal axis represents the motor generator MG1, the engine 200, and the motor generator MG2 in order from the left. Here, power split mechanism 300 is a planetary gear mechanism, and includes sun gear 303 (ie, substantially MG1), planetary carrier 306 (ie, substantially engine 200) and ring gear 301 (ie, substantially MG2). If the rotational speeds of the two elements are determined, the rotational speed of the remaining one element is inevitably determined. In other words, the operating state of each element on the alignment chart can be expressed as one straight line for one operating state of the hybrid drive apparatus 1000.

  For example, in FIG. 6, if the operating point of the motor generator MG2 is the white circle m1 shown in the figure and the operating point of the motor generator MG1 that bears the reaction torque of the engine 200 is the white circle m3 shown in the drawing, the operating point of the engine 200 is necessarily Thus, the white circle m2 is shown. Here, if the vehicle speed V (that is, the rotation speed Nmg2 of MG2 and the rotation speed of the drive shaft 302) is constant, the rotation speed Nmg1 of MG1 is controlled, and the operating point of MG1 is indicated by the white circle m4 shown in the figure. Or when it changes to the white circle m5, the operating point of the engine 200 changes to the white circle m6 or white circle m7 shown in the figure, respectively. Thus, in hybrid drive device 1000, motor generator MG1 can be used as a rotational speed control device, and engine 200 can be operated at a desired operating point. At this time, since the rotational speed of the drive shaft 302 does not change, the gear ratio inevitably changes steplessly. According to the hybrid drive device 1000, such a so-called electric CVT function can be obtained.

  The operating point of engine 200 is set according to an operating point map stored in ROM. Here, the operating point map will be described with reference to FIG. FIG. 7 is a schematic diagram conceptually showing the configuration of the operating point map.

  In FIG. 7, the operating point of the engine 200 includes an advance side operation line corresponding to the advance side valve timing or a retard side operation line corresponding to the retard side valve timing indicated by a solid line in the figure, an engine request It is set as a coordinate point where the iso-output line corresponding to the output intersects. 7 shows seven equal output lines EPi (i = 0, 1,..., 6) corresponding to the engine required output Pi (i = 0, 1,..., 6) as an example of the equal output lines. ., 6) are shown. For example, it is assumed that the current requested output of the engine 200 is P5. In this case, the operating point of the engine 200 is set to the illustrated operating point M0 (the engine rotational speed NE0 and the engine torque TE1) if the valve timing of the intake valve 207 is the advanced valve timing, and the valve timing of the intake valve 207 is If it is the retard side valve timing, it is set to the illustrated operation point M1 (also NE1 (NE1> NE0) and TE0 (TE0 <TE1)).

  Here, the advance side operation line and the retard side operation line (both are examples of the “operation line” according to the present invention) will be described. Each of the operation lines is an operation line obtained by connecting the optimum fuel consumption operating point at which the thermal efficiency of the engine 200 is maximized (the fuel consumption rate is minimized) with respect to the engine required output.

  When the valve timing of the intake valve 207 is the advance side valve timing, the valve overlap amount of the intake and exhaust valves is larger than when the retard side valve timing is selected. For this reason, in the high speed region, the intake charging efficiency is expected to be improved due to the exhaust inertia, and the maximum intake amount is increased compared to the retard side valve timing. Therefore, it is possible to set the operating point on the high load side (generally the side with higher thermal efficiency) than the retard side operating line. On the other hand, in the low speed region, a part of the exhaust is returned to the intake system, so that the intake charge efficiency is lowered at the advance side valve timing, and the intake amount is lower than the retard side valve timing.

  On the other hand, when the valve timing of the intake valve 207 is the retard side valve timing, the valve overlap amount of the intake and exhaust valves is reduced as compared with the case where the advance side valve timing is selected. Accordingly, the intake charge efficiency in the high rotation region is lower than the advance side valve timing, and the operating point must be set on the light load side with respect to the advance side operation line. On the other hand, in the low speed region, the internal EGR amount decreases compared to the advance side valve timing, so that the intake charging efficiency becomes higher than the advance side valve timing. As a result, the retard side operation line is set on the higher torque side than the advance side operation line.

  The operating point map has a configuration in which the values of the engine speed NE and the engine torque TE are associated with each operating point corresponding to the engine required output for each of the advance side operation line and the retard side operation line. The ECU 100 selectively acquires one operating point corresponding to the engine required output from one operating line corresponding to the valve timing of the intake valve 207 selected at that time, and operates the engine 200. The MG1, MG2, throttle valve 205, injector, and the like are controlled so that the point becomes the selected operating point.

  In particular, when switching the valve timing of the intake valve 207, it is necessary to switch the operation line between the advance side operation line and the retard side operation line. This operation line switching is performed by first and second operation line switching control described below. The operating lines shown in FIG. 7 are merely examples of operating lines that can be taken by the engine 200 in the hybrid drive apparatus 1000, and are appropriately modeled for easy understanding of the description. Therefore, the operation line of the engine 200 may of course have a mode other than that illustrated in FIG. 7, and even in this case, the effect according to the present embodiment described below is ensured.

<Details of first operation line switching control>
Here, the details of the first operation line switching control will be described with reference to FIG. FIG. 8 is a flowchart of the first operation line switching control.

  In FIG. 8, the ECU 100 determines whether or not the current time corresponds to the start period of the engine 200 (step S101). Note that the “start period” in the first operation line switching control is from the start time of the engine 200. This refers to a time region in which the elapsed time after engine startup, which is the elapsed time, is less than the reference delay time Tb of the VVT controller 216.

  Here, the reference delay time Tb is the time from when the engine is started until the operation restriction of the VVT controller 216 is released. Supplementally, the vane 219 can be rotated at a hydraulic pressure equal to or lower than the release hydraulic pressure, and when the vane 219 starts to rotate when the release hydraulic pressure is not reached, the vane 219 enters a so-called “biting” state. It may be unable to rotate. Therefore, basically, it is necessary to limit the operation of the VVT controller 216 until the hydraulic pressure is surely equal to or higher than the release hydraulic pressure (that is, until the reference delay time Tb elapses after the engine is started). Therefore, the value of the reference delay time Tb is determined in advance experimentally, empirically, theoretically, or based on a simulation or the like, after the engine is started, the hydraulic pressure higher than the release hydraulic pressure is surely supplied to the lock hole 223. Is set as the time.

  When the engine 200 is in the engine stop state or the start period of the engine 200 has already passed (step S101: NO), the ECU 100 waits for the process in step S101 and starts the engine 200 and the elapsed time after the start. Is less than the reference delay time Tb (step S101: YES), the ECU 100 determines whether or not there is a VVT advance angle request (step S102).

  Here, the “VVT advance request” is a request that the valve timing of the intake valve 207 should be set to the advance valve timing described above, and the ECU 100 determines the operating conditions of the hybrid vehicle 10 and the valve timing described above. The presence or absence is determined based on the map. In the present embodiment, the valve timing of the intake valve 207 is binary-switched between the advance side valve timing and the retard side valve timing, so that the VVT advance request is not generated. That is, this is equivalent to a state in which a request for setting the valve timing of the intake valve 207 to the retard side valve timing is generated. When there is no VVT advance angle request (step S102: NO), the ECU 100 returns the process to step S101 and repeats a series of processes.

  The first operation line switching control is control performed during the start period of the engine 200. When a VVT advance angle request is generated outside the engine start period, the VVT controller 216 is accompanied by various known control modes. Be controlled. Supplementally, if a VVT advance request is generated outside the engine start period, the lock hole 223 has already been applied with a hydraulic pressure equal to or higher than the release hydraulic pressure, so the forced maximum retard mode has already been released. Or it can be released immediately. Therefore, it is possible to immediately drive and control the VVT controller 216 in response to the VVT advance angle request.

  If there is a VVT advance request in step S102 (step S102: YES), the ECU 100 determines whether or not the engine stop period Te, which is a period of stop before the engine 200 is started, is equal to or less than the reference value Te0. (Step S103). In the hybrid vehicle 10, unlike a vehicle having only an internal combustion engine as a power source, so-called EV traveling can be performed only by the power of an electric motor (mainly MG2 in this embodiment). Therefore, the engine 200 determines that the driving condition of the hybrid vehicle 10 cannot be continued due to a change in the driving condition of the hybrid vehicle 10 during EV traveling other than when the ignition is turned on (physical, mechanical or electrical). There may be various determination factors such as various constraints or control constraints), etc., the starting thereof may be required as appropriate. The state in which the VVT advance angle request is generated during the engine start period is remarkably caused when the engine 200 is started during traveling in this way (for example, when the accelerator is stepped on and the hybrid vehicle 10 is in an accelerated state). For example, when the vehicle speed or the required output exceeds the range where EV travel is possible.

  Here, in a steady engine stop state in which a correspondingly long time has elapsed since the engine 200 stopped, the hydraulic pressure supplied to the VVT controller 216 is sufficiently reduced, and the vane is caused by the friction of the engine 200. Since 219 rotates to the most retarded position, the lock pin is fitted into the lock hole 223, and the control mode of the VVT controller 216 is the aforementioned forced most retarded mode. Therefore, it is practically impossible to start driving the VVT controller 216 at least until the above-described reference delay time Tb has elapsed.

  On the other hand, after the engine 200 is stopped, a corresponding elapsed time is required until the hydraulic pressure drops below the hydraulic pressure required to rotate the vane 219 or until the vane 219 rotates to the most retarded position. Therefore, for example, when the engine 200 is restarted without a sufficient interval after stopping the engine (particularly, it can occur sufficiently during EV traveling), the valve timing can be adjusted without waiting for the hydraulic pressure to rise. Control may be possible. In this way, the reference value Te0 according to step S102 is experimentally determined in advance as a time value that is estimated that a sufficient hydraulic pressure still remains to rotate the vane 219 with respect to the VVT controller 216. It is set empirically, theoretically or based on simulation.

  When the engine stop period Te is longer than the reference value Te0 (step S102: NO), the ECU 100 sets the VVT operation interval ΔTv to ΔTv1 (step S106) and when the engine stop period Te is equal to or less than the reference value Te0 (step S106). In step S102: YES, the ECU 100 sets the VVT operation interval ΔTv to ΔTv0 (step S104).

  Here, the VVT operation interval ΔTv is a delay time from the time when the VVT advance angle request is generated to the time when the ECU 100 starts the drive control of the VVT controller 216. Here, in particular, assuming that the elapsed time from when the engine starts to when the VVT advance angle request is generated (turned on) is Tp, the VVT operation interval ΔTv1 is defined by the following equation (1). Incidentally, the upper limit value of the elapsed time Tp is, of course, the reference delay time Tb. (If a value larger than the reference delay time is taken, it is outside the engine start period and deviates from the control range of the first operation line switching control. VVT control is performed).

ΔTv1 = ΔTv0 + (Tb−Tp) (1)
That is, the VVT operation interval ΔTv1 is a continuously variable value according to the elapsed time Tp, which takes ΔTv0 as the minimum value and ΔTv0 + Tb as the maximum value. ΔTv0 may be set to zero or may be set to a significant time value. However, from the viewpoint of quickly starting the operation of the VVT controller 216, zero or a small value corresponding thereto is set. It is desirable to set. When the VVT operation interval ΔTv is set in step S104 or step S106, the ECU 100 drives and controls the VVT controller 216 according to the set VVT operation interval ΔTv, and synchronizes with the set VVT operation interval ΔTv. The operation line of the engine 200 is switched in the form (step S105). When the operation line is switched, the process returns to step S101. The first operation line switching control is executed in this way.

  Here, the effect of the first operation line switching control will be described with reference to FIG. FIG. 9 is a schematic timing chart conceptually showing the operation of each unit when the first operation line switching control is executed.

  In FIG. 9, the operation state of the engine 200, the presence / absence of a VVT advance angle request, the VVT advance angle amount, and the engine output over time are shown in order from the top.

  It is assumed that engine 200 is started at time T1, and a VVT advance angle request is generated at time T2. Further, with respect to the VVT advance amount and the engine output, the time characteristic when the engine stop period Te is equal to or less than the reference value Te0 (hereinafter referred to as “first characteristic” as appropriate) is shown by a solid line, and the engine stop period Te is greater than the reference value. In this case, the time characteristic (hereinafter, referred to as “second characteristic” where appropriate) is expressed as a broken line.

  Here, according to the first characteristic, based on the determination that sufficient fluid pressure is applied to the VVT controller 216, the ECU 100 controls the drive of the VVT controller 216 at the time T3 when the ΔTv0 has elapsed from the time T2. Start. As a result, the vane 219 starts rotating at time T3, and at time T4, the VVT advance amount converges to A1 in the figure corresponding to the advance position of the vane 219 that defines the advance side valve timing. Further, since the operating line of engine 200 is also switched in synchronization with VVT operation interval ΔTv, the engine output also starts to increase at time T3 and converges to Pe0 which is the requested output at time T4. Actually, there is an operation delay that may occur in the physical, mechanical, or electrical configuration of the VT controller 216 from when the ECU 100 starts drive control to when the vane 219 of the VVT controller 216 starts rotating. Although it may occur, it is omitted here for the purpose of preventing the explanation from becoming complicated.

  On the other hand, according to the second characteristic, since it is determined that the VVT controller 216 is in the forced maximum retardation mode, the VVT operation interval ΔTv is set according to the above equation (1). Here, assuming that the deviation between the time T4 and the time T1 is the reference delay time Tb, the VVT controller 216 starts operation from the time T4 at the time T5 when the ΔTv0 has elapsed, and the vane 219 is separated from the time T5. At time T6, the VVT advance amount converges to A1 in the figure corresponding to the advance position of the vane 219 that defines the advance side valve timing. Further, since the operating line of engine 200 is also switched in synchronization with VVT operation interval ΔTv, the engine output also starts to increase at time T5 and converges to Pe0, which is the required output at time T6.

  As described above, according to the first operation line switching control according to the present embodiment, when the VVT advance angle request is generated during the engine start period, the VVT controller 216 is driven as early as possible without impairing the reliability. Control can be started. At this time, since the operation line of the engine 200 is also synchronized with the valve timing of the intake valve 207, the engine output can be improved at an early stage. It should be noted that the first operation line switching control is based on the point that the time required to restart the VVT controller 216 is shortened when the engine stop period is relatively short. The VVT controller 216 depends on the engine stop period. FIG. 8 and FIG. 9 show only one example, and the practical control mode is not limited to the above, and various modes can be adopted.

<Details of second operation line switching control>
Next, details of the second operation line switching control will be described with reference to FIG. FIG. 10 is a flowchart of the second operation line switching control.

  In FIG. 10, the ECU 100 determines whether or not the valve timing of the intake valve 207 has been switched from the advance side valve timing to the retard side valve timing (including a timing that can be clearly switched in the near future). Step S201). If it is not this type of switching timing (step S201: NO), the ECU 100 waits for processing in step S201, and if this type of switching timing is reached (step S201: YES), the ECU 100 drives the VVT controller 216. The valve timing of the intake valve 207 by the control is switched from the advance side valve timing to the retard side valve timing, and the engine speed deviation ΔNE is calculated by the following equation (2). The engine speed ΔNE is equal to or greater than the threshold value A. Whether or not (step S202).

ΔNE = NEbase−NEtag (2)
In equation (2), NEbase is a reference engine speed, and is an operating point set according to the engine required output (if the determination in step S201 branches to “YES” side, Engine speed). The reference engine speed NEbase is a transient target value of the engine speed of the engine 200, and is an example of the “reference value” according to the present invention. NEtag is a target rotational speed, and is a final target value of the engine rotational speed when the engine rotational speed is converged to the reference engine rotational speed. The target rotational speed NEtag is an example of the “target value” according to the present invention. The threshold A is an example of the “predetermined value” according to the present invention, but details of the threshold A will be described later.

  When the engine speed deviation ΔNE is less than the threshold A (step S202: NO), the ECU 100 sets the operation line switching time Tm to Tm2 (step S204), and when the engine speed deviation ΔNE is greater than or equal to the threshold A (step S204). Step S202: YES) The operation line switching time Tm is set to Tm1 (Tm1 <Tm2) (Step S203). When the operation line switching time Tm is set in step S203 or step S204, the ECU 100 switches the operation line of the engine 200 with the set operation line switching time Tm (step S205). When the switching of the operation line is completed, the process returns to step S201. The second operation line switching control is executed in this way.

  Here, the details of the second operation line switching control will be described with reference to FIG. FIG. 11 is a schematic timing chart conceptually showing the operation of each unit during the execution of the second operation line switching control. In the figure, the same reference numerals are given to the same portions as those in FIG. 9, and the description thereof will be omitted as appropriate.

  When referring to FIG. 7 before referring to FIG. 11, when the operation line is switched from the advance side operation line to the retard side operation line, the engine operating point is, for example, if the engine required output is P5 in the figure, The operating point M0 is switched to the operating point M1. In this case, the engine speed increases from NE0 to NE1. The switching of the operation line from the advance side operation line to the retard side operation line may occur qualitatively in the high speed region, and thus, in such a switching, the engine rotational speed NE may be basically increased. . In the description with reference to FIG. 11, the reference engine rotational speed NEbase before the operation line switching is NE0, and the reference engine rotational speed NEbase after the operation line switching is NE1.

  In FIG. 11, in order from the top, whether there is a VVT advance request, time characteristics of the reference engine speed NEbase and the target engine speed NEtag when ΔNE is equal to or greater than the threshold value A (hereinafter referred to as “first time characteristics” as appropriate). And time characteristics of the reference engine speed NEbase and the target engine speed NEtag (hereinafter referred to as “second time characteristics” as appropriate) when ΔNE is less than the threshold A. In each of the first and second time characteristics, the solid line corresponds to the reference engine speed NEbase, and the broken line corresponds to the target engine speed NEtag.

  In FIG. 11, it is assumed that the VVT advance angle request is turned off at time T10 and the valve timing of the intake valve 207 is switched from the advance side valve timing to the retard side valve timing. When the time from when the advance angle request is turned off to when the reference engine speed NEbase is set to the final target NE1 is defined as the operating line switching time Tm, according to the first characteristic, from the time T10 The operation line switching ends at time T11 when the operation line switching time Tm1 has elapsed.

  Here, the target engine speed NEtag is NE4 that is less than the reference engine speed NEbase (that is, NE0) at time T10 because the engine speed NE tends to increase before the VVT advance request is turned off. It finally converges to NE1 at time T12 later than time T11. That is, if the time from when the target rotational speed NEtag is set to when the engine rotational speed NE of the engine 200 actually follows it by the rotational control of the motor generator MG1 is ignored, in this case, the operating point of the engine 200 is actually The switching is at time T12.

  On the other hand, according to the second characteristic, the operation line switching ends at time T13 when the operation line switching time Tm2 has elapsed from time T10. Similar to the first characteristic, the target engine speed NEtag is less than the reference engine speed NEbase (ie, NE0) at time T10 because the engine speed NE tends to increase before the VVT advance request is turned off. NE5, and finally converges to NE1 at time T14 later than time T13. That is, if the time from when the target rotational speed NEtag is set to when the engine rotational speed NE of the engine 200 actually follows it by the rotational control of the motor generator MG1 is ignored, in this case, the operating point of the engine 200 is actually Switching occurs at time T14, and a time delay corresponding to the deviation between time T14 and time T12 is generated before the operating point is switched as compared with the case where the engine rotational speed deviation ΔNE is greater than or equal to the threshold A. .

  As described above, the operating point of the engine 200 is set so that the thermal efficiency of the engine 200 is as large as possible (or the system efficiency of the hybrid drive apparatus 1000 is as large as possible). The time required for switching the operating point is directly related to the fuel consumption of the hybrid vehicle 10. Therefore, the second characteristic is inferior to the first characteristic from the viewpoint of fuel consumption of the hybrid vehicle 10, apart from whether it can be manifested as a significant difference in practice.

  Thus, it is clear that the operation line switching time Tm is basically preferably shorter, but on the other hand, the change in the operation line switching time Tm in the shortening direction is similar to the operation line (the operation point is the same). It acts in a direction to increase the degree of fluctuation of the engine speed NE during the switching period.

  In the above example, when the engine speed deviation ΔNE is greater than or equal to the threshold A, the operating line switching speed is (NE1−NE0) / Tm1 and is the switching speed when the engine speed deviation ΔNE is less than the threshold A. It becomes higher than (NE1-NE0) / Tm2. This type of transient rotational fluctuation is a factor that causes a decrease in drivability. That is, qualitatively, fuel consumption and drivability are in a trade-off relationship during this type of operation line switching period.

  On the other hand, even if the rotation fluctuation occurs during the operation line switching period, if the corresponding rotation fluctuation has already occurred before the operation line switching, the effect on the drivability even if the degree of rotation fluctuation itself does not change. Is alleviated.

  Here, in particular, the magnitude of the engine rotational speed deviation ΔNE is uniquely related to the degree of fluctuation of the engine rotational speed NE before the operation line switching request is generated, and when the change in the reference engine rotational speed NEbase is large, Since the follow-up of the engine speed NEtag is delayed, ΔNE also increases. That is, the magnitude of ΔNE corresponds to the magnitude of the degree of rotational fluctuation on a one-to-one, one-to-many, many-to-one, or many-to-many basis.

  For example, referring to FIG. 11, in the first characteristic corresponding to the case where the engine speed deviation ΔNE is equal to or greater than the threshold value A, the rate of change of the engine speed before the operation line switching is (NE0−NE3) / dt1. = (NE4-NE2) / dt1, and is greater than (NE0-NE7) / dt1 = (NE5-NE6) / dt1, which is the rate of change in the second characteristic corresponding to the case where ΔNE is less than the threshold A. .

  Therefore, it is possible to appropriately control the operation line switching time based on the comparison determination result between the engine rotation speed deviation ΔNE and the threshold value A. In the present embodiment, the threshold A has a fluctuation of the engine speed such that a decrease in drivability is not manifested at least practically even when the operating line is switched early in accordance with the operating line switching time Tm1. In order to correspond to the case where it occurs, it is set in advance experimentally, empirically, theoretically, or based on simulation.

  As described above, according to the second operation line switching control, it is possible to switch the operation line as early as possible without causing a decrease in drivability, and to operate the engine 200 as efficiently as possible. It becomes possible.

  Here, the operation line switching time Tm is binary switched between Tm1 and Tm2, but the engine required output or the reference engine speed at the time when the VVT advance request changes from on to off. Depending on the value of NEbase, the operating line switching speed may change even if the operating line switching time Tm is the same. In view of this point, the operation line switching time Tm may be switched in multiple stages or continuously. That is, the essential technical idea of the present invention is to switch the operating line as early as possible after preventing excessive fluctuations in the engine speed before and after switching the operating line. As long as the magnitude of the engine rotational speed deviation ΔNE corresponds to the magnitude of the operating line switching time Tm, respectively, the operation line switching time or engine rotational speed deviation ΔNE for each target deviation is determined. Any threshold setting mode may be used, and in any case, it is a category of the operation of “controlling the operation line switching time in accordance with the specified deviation” according to the present invention.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and control of a hybrid vehicle involving such a change. The apparatus is also included in the technical scope of the present invention.

1 is a schematic configuration diagram conceptually illustrating a configuration of a hybrid vehicle according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram conceptually showing a configuration of a hybrid drive device mounted on the hybrid vehicle of FIG. 1. FIG. 3 is a schematic view illustrating a one-plane configuration of an engine that constitutes the hybrid drive device of FIG. 2. FIG. 2 is a schematic cross-sectional view of a VVT controller provided in the hybrid vehicle of FIG. 1 on a plane orthogonal to an intake camshaft. It is a schematic diagram of the hydraulic-pressure transmission system which drives the VVT controller of FIG. FIG. 3 is an operation alignment chart for explaining an operation state of each part of the hybrid drive device of FIG. 2. It is a schematic diagram conceptually showing the configuration of an operating point map. It is a flowchart of the 1st operation line switching control performed by ECU. FIG. 9 is a schematic timing chart conceptually showing the operation of each unit when the first operation line switching control of FIG. 8 is executed. It is a flowchart of the 2nd operation line switching control performed by ECU. FIG. 11 is a schematic timing chart conceptually showing the operation of each unit when the second operation line switching control in FIG. 10 is executed.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine system, 100 ... ECU, 200 ... Engine, 201 ... Cylinder, 216 ... VVT controller, 217 ... Housing, 218 ... Rotor, 219 ... Vane, 220 ... Advance angle chamber, 221 ... Delay angle chamber, 223 ... Lock hole DESCRIPTION OF SYMBOLS 225 ... Fluid pressure transmission system, 226 ... Fluid pressure control valve, 227 ... Spring, 228 ... Solenoid, 300 ... Power split mechanism, 1000 ... Hybrid drive unit, MG1, MG2 ... Motor generator.

Claims (2)

As a power source, comprising an internal combustion engine having a variable valve gear capable of changing the opening timing of the intake valve and at least one electric motor,
And further comprising power distribution means including a plurality of rotating elements capable of differentially rotating with each other, including rotating elements respectively connected to an engine output shaft of the internal combustion engine and an output shaft of the at least one electric motor.
A control device for a hybrid vehicle configured to be able to switch an operation line of the internal combustion engine by a differential action of the plurality of rotating elements in the power distribution means,
Switching means for switching the operation line according to the valve opening timing;
A specifying means for specifying a deviation between a reference value of the engine speed of the internal combustion engine based on a required output of the hybrid vehicle and a target value of the engine speed;
A control device for a hybrid vehicle, comprising: a control unit that controls a switching time of the operation line according to the specified deviation when the valve opening timing changes to the retard side. 2. The hybrid according to claim 1, wherein when the specified deviation is equal to or greater than a predetermined value, the control unit shortens the switching time compared to a case where the deviation is less than the predetermined value. Vehicle control device.

Images