JP2011144784A - Control device for vehicle - Google Patents

Abstract

In a vehicle control apparatus, the response of a vehicle behavior to a driver's operation is improved, and a shock that occurs during gear shifting is reduced.
A control device for a vehicle (100) controls a vehicle including an engine (10) having a variable compression ratio and a transmission means (110) having a variable gear ratio. The control device includes a control unit (60) that shifts the actual engine operating point from the engine operating point before the change to the target engine operating point when the required driving force changes, and a compression ratio changing unit that changes the compression ratio ( 60). Compression ratio changing means when the compression ratio at the target operating point is set lower than the engine operating point before the change and the rotational speed ratio at the target operating point is set lower than the engine operating point before the change. Changes the compression ratio while changing the gear ratio.
[Selection] Figure 5

Description

  The present invention relates to a vehicle control apparatus including a variable compression ratio engine.

  As an example of this type of vehicle control device, there is one that controls a vehicle including a variable compression ratio engine capable of changing the compression ratio of the air-fuel mixture in each cylinder. In the variable compression ratio engine, the efficiency (that is, the thermal efficiency) when converting engine power into mechanical work according to the driving state of the vehicle (for example, the operation content of the driver and the road surface state), The compression ratio is controlled so as to balance the increase in the maximum output of the engine. For example, under conditions where high torque is required, the compression ratio is set low to ensure a sufficient maximum output, and under conditions where low to medium torque is required, the compression ratio is set high to improve thermal efficiency. be able to.

  Here, when the required driving force for the vehicle changes, a shift may be performed in a transmission such as a transmission provided in the vehicle in order to shift the engine operating point to correspond to the required driving force. For example, Patent Document 1 discloses a technique for changing a compression ratio after completing a shift. Patent Document 2 discloses a technique for changing a compression ratio before executing a shift so as to reduce a shock caused by an inertia torque of the engine during the shift. Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique for achieving both reduction of shock during shifting and improvement of engine responsiveness by providing a plurality of means capable of controlling the output torque of the engine.

Japanese Patent Laid-Open No. 03-064632 JP 2008-014168 A JP 2007-327418 A

  However, in Patent Documents 1 and 2, since the change of the compression ratio is performed outside the period during which the shift is executed, the period required for completing the series of operations related to the transition of the engine operating point and the change of the compression ratio is long. There is a technical problem that it becomes longer. That is, there is a possibility that vehicle responsiveness may not be sufficiently obtained when it is necessary to shift the engine operating point due to a driver's requested operation. Further, in Patent Document 1, since no measures are taken to reduce the shock caused by the inertia torque of the engine or the like at the time of shifting, the drivability deteriorates due to the shock generated at the time of shifting. There are some problems. Patent Document 3 makes no mention of a variable compression ratio engine, and is intended to reduce the shock at the time of shifting in a vehicle equipped with a variable compression ratio engine and to improve the responsiveness of the vehicle when shifting the engine operating point. There is a technical problem that is difficult.

  The present invention has been made in view of the above problems, for example, and provides a vehicle driving force control device capable of improving the response of the behavior of a vehicle to a driver's requested operation and reducing a shock generated during a shift. This is the issue.

  In order to solve the above-described problems, a first vehicle control apparatus according to the present invention is connected to an engine capable of changing a compression ratio indicating the degree of compression of an air-fuel mixture, an output shaft of the engine, and an axle. And a speed change means having a variable rotational speed ratio with the output member. When the required driving force of the vehicle changes, the required drive after the change from the engine operating point before the change Control means for shifting the actual engine operating point, which is the actual engine operating point, to the target engine operating point, which is the engine operating point corresponding to the force, and compression ratio changing means for changing the compression ratio in accordance with the transition of the actual engine operating point And the compression ratio at the target operating point is set lower than the engine operating point before the change of the required driving force, and the rotation speed ratio at the target operating point changes the required driving force. If it is smaller than the previous engine operating point, the compression ratio changing means, while said control means is allowed to change the rotational speed ratio to change the compression ratio.

  A vehicle which is a control target of the first vehicle control device according to the present invention is provided with an engine and a transmission means.

  The engine is a variable compression ratio engine in which the compression ratio indicating the degree of compression of the air-fuel mixture is variable using, for example, an actuator supplied with electric power from a battery. For example, the variable compression ratio engine changes the compression ratio in accordance with the driving conditions of the vehicle so that the conversion efficiency into mechanical work, that is, the improvement in thermal efficiency, and the increase in the maximum output can be compatible. Specifically, a sufficient maximum output can be ensured by setting the compression ratio low under high torque conditions, and thermal efficiency can be improved by setting the compression ratio high under low to medium torque conditions.

  The speed change means is a power transmission mechanism capable of changing a rotational speed ratio (hereinafter referred to as “speed ratio” as appropriate) between the output shaft of the engine and an output member connected to the axle. The speed change means is, for example, a plurality of engagement means (including a brake device and a clutch device) that can take various forms such as a friction engagement type or a meshing type, so that the output member and the plurality of rotating elements are connected (that is, the original) Regardless of whether connection is possible or not, it includes at least the presence or absence of connection, and conceptually includes a quantitative state such as how much is connected (ie, among these multiple rotating elements) It is possible to change the speed by, for example, appropriately engaging and separating at least a part of the output member that can be brought into and out of contact with the output member as a suitable form. The speed change is theoretically substantially equivalent to the rotational speed ratio (ie, gear ratio) between the rotational speed of the output shaft of the engine (ie, engine speed) and the output member connected directly or indirectly to the axle. Or within some practical constraints.

  The vehicle control apparatus according to the present invention is, for example, an ECU (Electronic Controlled Unit), and includes a control unit and a compression ratio changing unit.

  When the required driving force of the vehicle changes, the control means performs actual engine operation as an actual engine operating point from an engine operating point before the change to a target engine operating point as an engine operating point corresponding to the changed required driving force. Move points. The engine operating point is an operating point defined by one or a plurality of parameters for defining the engine operating state such as the engine output torque and the rotational speed. Here, the required driving force of the engine may be calculated based on, for example, the content of the requested operation of the driver by the vehicle, the condition of the traveling road surface, and the like. Thus, when the required driving force changes, the engine operating point is shifted by the control means in order to output the required driving force from the engine. There are several possible paths for the engine operating point before and after the required driving force changes. For example, both conversion efficiency to mechanical work, that is, improvement in thermal efficiency and increase in maximum output are compatible. It is advisable to select as appropriate.

  The compression ratio changing means changes the compression ratio as the actual engine operating point shifts. The compression ratio changing means changes the compression ratio by, for example, changing the capacity of the combustion chamber by adjusting the valve timing, lift amount, and EGR amount of the engine.

  In the present invention, in particular, the compression ratio at the target operating point is set lower than the engine operating point before the required driving force changes, and the rotational speed ratio at the target operating point is higher than the engine operating point before the required driving force changes. Is set to be smaller, the compression ratio changing means changes the compression ratio while the control means is changing the rotation speed ratio. Here, when the engine operating point shifts by the control means, the rotation speed ratio of the speed change means is changed (that is, speed change is performed) and is applied to the output member connected to the axle due to the inertia torque. The torque (hereinafter referred to as “output shaft torque” as appropriate) may change. Such a change in output shaft torque is perceived as a shock by the driver, which may lead to deterioration of drivability. When the rotational speed ratio is changed to be smaller than that before the change (that is, when upshifting is performed), the output shaft torque varies temporarily due to the inertia torque corresponding to the amount of change in the rotational speed ratio. May occur. In the present invention, the shock is reduced and the drivability is improved by reducing the compression ratio while the shift is being executed (that is, while the rotational speed ratio is changing with the shift). Can do. If the compression ratio is reduced in such a case, the engine output torque changes in a direction to cancel the inertia torque generated at the time of shifting, so that the shock caused by the inertia torque can be effectively reduced.

  Further, in the present invention, since the compression ratio is changed while the gear shift is being executed, a period for changing the compression ratio before and after the gear shift is executed as in Patent Document 1 or 2 described above. There is no need to provide it separately. That is, in Patent Document 1 or 2, the time required to complete a series of operations related to gear shifting (that is, transition of the engine operating point and change of the compression ratio) is required at least for changing the rotational speed ratio by the speed change means. The time is added to the time required to change the compression ratio before and after. On the other hand, in the present invention, since the compression ratio is simultaneously changed while the rotation speed ratio is being changed, the time required to complete a series of operations related to the shift can be reduced. Therefore, it is possible to improve the response of the vehicle to the driver's requested operation.

  As described above, according to the vehicle control apparatus of the present invention, it is possible to improve the responsiveness of the behavior of the vehicle with respect to the driver's requested operation, and to reduce the shock generated at the time of shifting.

  In order to solve the above-described problem, a second vehicle control apparatus according to the present invention is connected to an engine capable of changing a compression ratio indicating the degree of compression of an air-fuel mixture, an output shaft of the engine, and an axle. And a speed change means having a variable rotational speed ratio with the output member. When the required driving force of the vehicle changes, the required drive after the change from the engine operating point before the change Control means for shifting the actual engine operating point, which is the actual engine operating point, to the target engine operating point, which is the engine operating point corresponding to the force, and compression ratio changing means for changing the compression ratio in accordance with the transition of the actual engine operating point And the compression ratio at the target operating point is set to be larger than the engine operating point before the change of the required driving force, and the rotational speed ratio at the target operating point is equal to the required driving force. If it is set larger than the reduction before the engine operating point, the compression ratio changing means, while said control means is allowed to change the rotational speed ratio to change the compression ratio.

  The vehicle control device according to the present invention is controlled by a vehicle including an engine and a transmission unit, similarly to the above-described first vehicle control device. The vehicle control apparatus according to the present invention is, for example, an ECU (Electronic Controlled Unit), and includes a control unit and a compression ratio changing unit.

  Particularly in the present invention, the compression ratio at the target operating point is set to be larger than the engine operating point before the change of the required driving force, and the engine at the rotational speed ratio at the target operating point before the change of the required driving force is set. When it is set larger than the operating point, the compression ratio changing means changes the compression ratio while the control means is changing the rotation speed ratio. Here, when the rotational speed ratio is largely changed compared to before the change (that is, when downshifting is performed), the output shaft torque temporarily varies due to the inertia torque corresponding to the amount of change in the rotational speed ratio. May cause a shock. In the present invention, the shock is reduced and the drivability is improved by reducing the compression ratio while the shift is being executed (that is, while the rotational speed ratio is changing with the shift). Can do. If the compression ratio is increased in such a case, the output torque of the engine changes in a direction to cancel the inertia torque generated at the time of shifting, so that the shock caused by the inertia torque can be effectively reduced.

  Further, in the present invention, since the compression ratio is changed while the shift is being executed, the time required for completing a series of operations related to the shift is the same as in the case of the first vehicle control device described above. Can be kept short. As a result, it is possible to improve both the response of the behavior of the vehicle to the driver's requested operation and the reduction of the shock generated at the time of shifting.

  In one aspect of the first and second vehicle control devices according to the present invention, when the amount of change in the engine speed before and after the transition of the actual engine operating point is greater than a predetermined threshold, the target operating point The compression ratio changing means changes the compression ratio to the corrected compression ratio while the control means is changing the rotation speed ratio.

  According to this aspect, when the change in the engine speed is large when the engine operating point shifts and it is expected that improvement of drivability is difficult, the compression ratio is changed during the shift. Therefore, the compression ratio is corrected so that improvement in drivability can be expected. When the amount of change in the engine speed before and after the transition of the engine operating point increases, the inertia torque applied to the drive shaft at the time of shifting increases, so the driver can be changed by changing the compression ratio during shifting. In some cases, it may be difficult to obtain a sufficient effect even if it is attempted to improve the performance. The predetermined threshold value is the amount of change in the engine speed at which it is difficult to obtain a sufficient effect even if it is attempted to improve drivability by changing the compression ratio during the execution of gear shifting. Is defined as Actually, the threshold value α may be calculated from the above conditions by a theoretical, experimental method, simulation, or the like.

  Thus, when the amount of change in the engine speed before and after the transition of the engine operating point is large, the correction means corrects the compression ratio at the target operating point. Here, this correction corrects the compression ratio at the target engine operating point so that the output torque of the engine is adjusted to a value that can reduce the inertia torque applied to the drive shaft at the time of shifting. By correcting the compression ratio in this way, even when the amount of change in the engine speed is large and the inertia torque applied to the drive shaft is large, the compression ratio is adjusted during the shift. By changing the time, it is possible to reduce the time required to complete a series of operations related to shifting, and to improve the responsiveness of the vehicle to a request operation from the driver.

  In this case, the correction means sets the compression ratio to the compression ratio before the correction after the transition of the actual engine operating point is completed, and the compression ratio change means sets the compression ratio to the correction ratio. The compression ratio may be changed so that the compression ratio is the same as before compression.

  As described above, drivability can be improved by correcting the compression ratio at the target engine operating point even when the amount of change in the engine speed at the time of shifting is large. In this case, when the series of operations related to the shift is completed, the compression ratio is deviated from the original compression ratio by the amount corrected, so that the compression ratio is returned to the original target compression ratio after the shift is completed. It is good to control.

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

1 is a schematic configuration diagram conceptually illustrating a configuration of a vehicle according to a first embodiment. It is a mimetic diagram showing roughly the whole engine composition which vehicles have concerning a 1st embodiment. It is a graph which shows notionally the mode of the transition of the engine operating point according to the change of the driving state of the vehicle which concerns on 1st Embodiment. 4 is a time chart showing changes over time in engine speed, compression ratio, and output shaft torque when the engine operating point shifts along the route indicated by (i) in FIG. 3 in the vehicle according to the first embodiment. It is a flowchart of the control processing for implement | achieving operation | movement of the vehicle which concerns on 1st Embodiment. It is a flowchart of the control processing for implement | achieving operation | movement of the vehicle which concerns on 2nd Embodiment. It is a graph which shows an example of the 1st correction value of the target compression ratio in the vehicle which concerns on 2nd Embodiment. FIG. 4 is a time chart showing changes over time in engine speed, compression ratio, and output shaft torque when the engine operating point shifts along the route indicated by (i) in FIG. 3 in the vehicle according to the second embodiment. It is a flowchart of the control processing for implement | achieving operation | movement of the vehicle which concerns on 3rd Embodiment. It is a graph which shows an example of the 2nd threshold value (gamma) of the vehicle which concerns on 3rd Embodiment. In the vehicle which concerns on 3rd Embodiment, it is a time chart which shows the time change of an engine speed, a compression ratio, a 2nd correction value, and an output shaft torque when an engine operating point transfers in the route | root shown by (ii) in FIG. is there.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a vehicle control apparatus according to the present invention will be described with reference to the drawings.

<First Embodiment>
First, a first embodiment according to the present invention will be described with reference to FIGS.

<Configuration of Embodiment>
A schematic configuration of a vehicle 100 according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram conceptually showing the configuration of a vehicle 100 according to the present embodiment.

  The vehicle 100 includes an engine 10, a continuously variable transmission 110, an ECU (Electronic Controlled Unit) 60, and an accelerator opening sensor 61. The engine 10 is an example of the “engine” according to the present invention, the continuously variable transmission 110 is an example of the “transmission unit” according to the present invention, and the ECU 60 is the “control unit” and the “compression” according to the present invention. It is an example of “ratio changing means”.

  Although described in detail later, the engine 10 is a variable compression ratio engine in which the compression ratio indicating the degree of compression of the air-fuel mixture is variable. The engine 10 has a plurality of cylinders 34. In the present embodiment, the engine 10 is an inline 4-cylinder engine. The engine 10 has an intake passage 50 for supplying intake air into the combustion chamber of each cylinder 34 and an exhaust passage 58 for discharging exhaust gas from the combustion chamber of each cylinder 34. The intake passage 50 is provided with a throttle valve 52 for adjusting the intake air amount supplied into the combustion chamber of each cylinder 34 and an air flow sensor 57 for detecting the intake air amount. The opening degree of the throttle valve 52 can be adjusted by the electric actuator 53. The engine 10 is controlled by a control signal supplied from an ECU (Electronic Controlled Unit) 60.

  The output torque of the engine 10 is transmitted to the continuously variable transmission 110 via the crankshaft 43. The continuously variable transmission 110 includes a primary pulley 110a, a secondary pulley 110b, and a belt 111 made of metal or the like wound around both pulleys. The belt effective diameter is changed by moving the movable sheaves 110aa and 110ba of both pulleys in the axial direction (the direction indicated by the double-ended arrows). The output torque of the engine 10 is shifted when it is transmitted from the primary pulley 110a to the secondary pulley 110b. The secondary pulley 110 b is connected to the drive shaft 143, and the output from the secondary pulley 110 b is transmitted to the drive shaft 143. The output transmitted to the drive shaft 143 is transmitted to the drive wheels and is used for traveling of the vehicle 100. Thus, the gear ratio of the continuously variable transmission 110 is continuously variable. The gear ratio of the continuously variable transmission 110 is an example of the “rotational speed ratio” according to the present invention. The continuously variable transmission 110 is controlled by a control signal from the ECU 60. The continuously variable transmission 110 is not limited to a belt-type continuously variable transmission, and various other stepped transmissions and continuously variable transmissions may be used instead.

  The ECU 60 includes a CPU, a ROM, a RAM, an A / D converter, and the like (not shown). The ECU 60 controls the vehicle 100 based on detection signals supplied from various sensors in the vehicle. For example, the ECU 60 obtains a required driving force that is a driving force required for the vehicle based on a detection signal received from a sensor such as an accelerator opening sensor 61 that detects the accelerator opening, and based on the required driving force. The engine 10 and the continuously variable transmission 110 are controlled.

  Next, a specific configuration of the engine 10 of the vehicle 100 according to the present embodiment will be described with reference to FIG. FIG. 2 is a schematic diagram schematically showing the overall configuration of the engine of the vehicle according to this embodiment.

  The engine 10 mainly includes a cylinder head 20, a cylinder block unit 30, and a main moving unit 40.

  The cylinder block unit 30 includes an upper block 31 to which the cylinder head 20 is attached and a lower block 32 in which the main moving unit 40 is accommodated. An actuator 33 is provided between the upper block 31 and the lower block 32. By driving the actuator 33, the upper block 31 can be moved in the vertical direction with respect to the lower block 32. The actuator 33 is, for example, an electric, hydraulic or pneumatic driving device, and is supplied with electric power for driving from a battery (not shown). The operation of the actuator 33 is controlled by a control signal S33 from the ECU 60. A cylindrical cylinder 34 is formed inside the upper block 31, and the outer surface of the cylinder 34 is cooled by cooling water.

  The main moving 40 includes a piston 41 provided inside the cylinder 34, a crankshaft 43 that rotates inside the lower block 32, a connecting rod 42 that connects the piston 41 to the crankshaft 43, and the like. These constitute a so-called crank mechanism. As the crankshaft 43 rotates, the piston 41 moves up and down in the cylinder 34 as the crankshaft 43 rotates. Conversely, if the piston 41 moves up and down, the crankshaft 43 moves into the lower block 32. Rotate with.

  In the vicinity of the crankshaft 43, a crank angle sensor 44 for sensing the crank angle is provided. The crank angle sensor 44 transmits a detection signal S44 corresponding to the detected crank angle to the ECU 60.

  A combustion chamber is formed in a portion surrounded by the lower surface side (the side in contact with the upper block 31) of the cylinder head 20, the cylinder 34 and the piston 41. The engine 10 can change the capacity of the combustion chamber and change the compression ratio by driving the actuator 33. For example, if the upper block 31 is moved upward using the actuator 33, the cylinder head 20 is also moved upward along with this, and the volume of the combustion chamber increases, so that the compression ratio is changed to be low. On the contrary, if the cylinder head 20 is moved downward together with the upper block 31, the volume of the combustion chamber is reduced and the compression ratio can be changed to be high.

  In the variable compression ratio engine, the compression ratio of the air-fuel mixture is changed in accordance with the operating conditions in order to achieve both improvement in conversion efficiency to mechanical work, that is, improvement in thermal efficiency and increase in maximum output. For example, the ECU 60 can ensure a sufficient maximum output by setting the compression ratio low under a high torque condition, and can improve the thermal efficiency by setting the compression ratio high under a low / medium torque condition.

  The compression ratio is detected by using a compression ratio sensor 63 provided in the lower block 32. As the compression ratio sensor 63, for example, a stroke sensor is used, and the compression ratio can be detected by detecting the relative position of the upper block 31 with respect to the lower block 32. The compression ratio sensor 63 transmits a detection signal S63 corresponding to the detected compression ratio to the ECU 60.

  The cylinder head 20 is provided with an intake port 23 for taking intake air into the combustion chamber and an exhaust port 24 for discharging exhaust gas from the combustion chamber. An intake passage 50 is connected to the intake port 23, and an exhaust passage 58 is connected to the exhaust port 24. Here, an intake valve 21 is provided at a portion where the intake port 23 opens into the combustion chamber, and an exhaust valve 22 is provided at a portion where the exhaust port 24 opens into the combustion chamber. The intake valve 21 and the exhaust valve 22 are driven by electric actuators 73 and 74, respectively. By opening and closing the intake valve 21 and the exhaust valve 22 at an appropriate timing in accordance with the movement of the piston 41, intake air can be drawn into the combustion chamber or exhaust gas can be discharged from the combustion chamber. The electric actuators 73 and 74 that drive the intake valve 21 and the exhaust valve 22 are controlled by control signals S73 and S74 from the ECU 60.

  The air flow sensor 57 provided in the intake passage 50 transmits a detection signal S57 corresponding to the detected intake air amount to the ECU 60. The electric actuator 53 for adjusting the opening of the throttle valve 52 is controlled by a control signal S53 from the ECU 60.

  The cylinder head 20 is provided with a fuel injection valve 26 for injecting fuel into the combustion chamber and an ignition plug 27 for igniting an air-fuel mixture formed in the combustion chamber. The fuel injection valve 26 and the spark plug 27 are controlled by control signals S26 and S27 from the ECU 60. When the fuel injection valve 26 injects fuel into the combustion chamber, a mixture of intake air and fuel sucked from the intake passage 50 via the intake port 23 is formed in the combustion chamber, and the spark plug 27 ignites. The air-fuel mixture is burned. The force pushing the piston 41 generated by the combustion at this time becomes the power of the engine 10. Thereafter, the exhaust in the combustion chamber is discharged to the exhaust passage 58 via the exhaust port 24. The fuel injection valve is not limited to providing the direct injection type fuel injection valve 26 as shown in FIG. 2. Instead of or in addition to this, a fuel injection valve may be provided in the intake passage 50. .

<Operation of Embodiment>
Next, the operation of the vehicle according to the present embodiment will be described with reference to FIG. FIG. 3 is a graph conceptually showing the transition of the engine operating point according to the change in the running state of the vehicle 100 according to the present embodiment.

  In FIG. 3, the horizontal axis indicates the engine speed Ne, the vertical axis indicates the engine torque Te, and the dotted lines LPrl, LPrm, and LPra shown in the figure indicate equal compression ratio lines. FIG. 3 shows LPrl, LPrm, and LPra as typical isocompression ratio lines, and the compression ratio Cr increases in the order of LPrl, LPrm, and LPra.

  In FIG. 3, three points of Ap, Bp, and Cp are illustrated as engine operating points. Ap, Bp, and Cp indicate three engine operating points at which the engine torque Te, the engine speed Ne, and the compression ratio Cr are different from each other. Each dotted arrow in FIG. 3 indicates a route along which the engine operating point shifts in accordance with a driver's operation or a change in the running state of the vehicle 100 (for example, a road surface condition on which the vehicle 100 is to run).

  First, the operation of the vehicle 100 when the engine operating point shifts from Ap to Bp (that is, when indicated by (i) in FIG. 3) will be described. In this case, the engine torque Te increases before and after the engine operating point shifts, while the engine speed Ne decreases. In FIG. 3, when the engine operating point shifts along the route indicated by (i), the continuously variable transmission 110 shifts up.

  Here, the behavior of the vehicle when the engine operating point shifts along the route indicated by (i) in FIG. 3 will be described with reference to FIG. FIG. 4 is a time chart showing temporal changes in the engine speed Ne, the compression ratio Cr, and the output shaft torque To when the engine operating point shifts along the route indicated by (i) in FIG. The output shaft torque To is a torque value applied to the drive shaft 143.

  FIG. 4A is a time chart showing the change over time of the engine speed Ne. The engine speed Ne is initially maintained at Ne1, and gradually decreases from time t1 at which shifting is started by the continuously variable transmission 110 as the engine operating point shifts. Thereafter, the engine speed Ne reaches Ne2 at time t4 and is kept constant. Since the vehicle 100 according to the present embodiment includes the continuously variable transmission 110 whose transmission ratio is continuously variable as a transmission, the engine speed Ne is also continuously changing.

  FIG. 4B is a time chart showing the time change of the compression ratio Cr. The compression ratio Cr is initially maintained at Cr1, and gradually decreases from time t2 as the engine operating point shifts. Thereafter, it reaches Cr2 at time t3 and is kept constant. Here, the period during which the compression ratio Cr changes (ie, the period from t2 to t3) is included in the period during which the engine speed Ne changes (ie, the period from t1 to t4). In other words, the compression ratio Cr is controlled by the ECU 60 so that the compression ratio Cr changes while the gear is being changed by the continuously variable transmission 110.

  FIG. 4C is a time chart showing a time change of the output shaft torque To of the vehicle 100 according to the present embodiment with a solid line and a time change of the output shaft torque To of the vehicle according to the comparative example with a dotted line.

  Here, the time change of the output shaft torque To of the vehicle 100 according to the present embodiment will be described with reference to a comparative example. The comparative example differs from the vehicle 100 according to the present embodiment in that the compression ratio Cr is changed after the shift is completed (in this embodiment, the shift is executed as shown in FIG. 4B). The compression ratio Cr is changed during the process). In the comparative example, the structure and control similar to those of the vehicle according to the present embodiment are performed except that the compression ratio Cr is changed after the shift is completed. To do.

  As shown in FIG. 4A, when the engine speed Ne decreases from Ne1 to Ne2 due to the shift up, an inertia torque corresponding to the engine speed Ne acts on the drive shaft 143 and is applied to the drive shaft 143. The output shaft torque To, which is a torque value, varies. In the comparative example, no countermeasure is taken to reduce such fluctuations in the output shaft torque To, so the fluctuations in the output shaft torque To are transmitted as a shock to the driver, leading to deterioration in drivability (FIG. 4). (See (c) dashed line).

  On the other hand, in the vehicle 100 according to the present embodiment, the change in the output shaft torque To can be reduced by changing the compression ratio Cr while the shift is being executed. When the engine operating point is shifted along the route (i) shown in FIG. 3, the engine 10 is controlled so that the compression ratio Cr decreases before and after the transition. When the compression ratio Cr is reduced in this way, the output torque of the engine 10 changes in a direction to cancel the inertia torque generated at the time of shifting, so that the shock caused by the inertia torque can be effectively reduced (FIG. 4 (c)). ) (See solid line).

  In the comparative example, since the compression ratio Cr is not changed while the shift is being executed, it is necessary to separately provide a period for changing the compression ratio Cr before and after the shift is executed. For this reason, the time required to complete a series of operations related to the speed change includes at least the time required to change the speed ratio by the continuously variable transmission 110 and the time required to change the compression ratio Cr before and after that. It will be. On the other hand, in the vehicle 100 according to the present embodiment, the compression ratio Cr also changes at the same time while the shift is being executed, so that the time required to complete a series of operations related to the shift is reduced compared to the comparative example. be able to. Therefore, the responsiveness of vehicle 100 can be improved in response to a request operation from the driver.

  Next, the operation of the vehicle 100 when the engine operating point shifts from Cp to Ap (that is, when indicated by (ii) in FIG. 3) will be described. In this case, the engine torque Te and the engine speed Ne both decrease before and after the transition of the engine operating point. When the engine operating point shifts along the route indicated by (ii) in FIG. 3, the continuously variable transmission 110 shifts up.

  In the engine operating point transition route shown in FIG. 3 (ii), as in FIG. 3 (i), the continuously variable transmission 110 is upshifted, but the compression ratio Cr is not decreased but increased. It is different in that it is doing. For this reason, if the compression ratio Cr is changed while gear shifting is being executed, the change in the engine output torque acts in the direction of amplifying the inertia torque, contrary to the case of FIG. The drivability may be further deteriorated. Therefore, the engine operating point transition route shown in FIG. 3 (ii) differs from the engine operating point transition route shown in FIG. 3 (i) so that the compression ratio Cr is changed during shifting. By not doing so, deterioration of drivability can be suppressed.

  Next, the operation of the vehicle 100 when the engine operating point shifts from Bp to Ap (that is, the case indicated by (iii) in FIG. 3) will be described. In this case, the engine torque Te decreases before and after the transition of the engine operating point, and the engine speed Ne increases. Therefore, when the engine operating point shifts along the route indicated by (iii) in FIG. 3, the continuously variable transmission 110 performs a downshift.

  When the engine operating point shifts along the route indicated by (iii) in FIG. 3, the compression ratio changes in the increasing direction as in FIG. 3 (ii) described above, while the continuously variable transmission is changed to FIG. In contrast to), downshift is performed. Therefore, the inertia torque generated at the time of shifting is in the reverse direction compared to the case of FIG. 3 (ii) described above. Therefore, in FIG. 3 (ii), the change in the output shaft torque To was reduced by not intentionally changing the compression ratio during the shift, but in FIG. 3 (iii), conversely (that is, similar to FIG. 3 (i)). In addition, it is possible to reduce fluctuations in the output shaft torque To by changing the compression ratio while the shift is being executed.

  As described above, in the case of FIG. 3 (iii), as in the case of FIG. 3 (i), a series of operations relating to the shift is completed by simultaneously changing the compression ratio Cr during the shift. Therefore, the time required for this can be kept short, and the responsiveness of the vehicle 100 to the requested operation from the driver can be improved.

  Next, the operation of the vehicle 100 when the engine operating point shifts from Ap to Cp (that is, when indicated by (iv) in FIG. 3) will be described. In this case, both the engine torque Te and the engine speed Ne increase before and after the transition of the engine operating point. When the engine operating point shifts along the route indicated by (iv) in FIG. 3, the continuously variable transmission 110 shifts down.

  In the engine operating point transition route shown in FIG. 3 (iv), the downshift is performed in the continuously variable transmission 110 as in FIG. 3 (iii), but the compression ratio Cr is not increased but decreased instead. Is different. Therefore, if the compression ratio Cr is changed while gear shifting is being executed, a change in the engine output torque acts in the direction of amplifying the inertia torque, contrary to the case of FIG. 3 (iii). The drivability may be further deteriorated. Therefore, the engine operating point transition route shown in FIG. 3 (iv) differs from the engine operating point transition route shown in FIG. 3 (iii) to change the compression ratio Cr during shifting. By not doing so, deterioration of drivability can be suppressed.

  In the case of FIGS. 3 (ii) and 3 (iv), the compression ratio Cr must be changed before and after the shift is executed, so that the time required for a series of operations related to the shift becomes longer. The response may be slow. However, since there is a great merit of improving drivability by reducing fluctuations in the output shaft torque To, there is no substantial problem. However, even if the compression ratio Cr is changed during shifting, the responsiveness of the vehicle 100 to the driver's requested operation, such as when the deterioration of drivability due to the fluctuation of the output shaft torque To is very small, etc. Needless to say, the compression ratio Cr may be changed while the gear shift is being executed in the same way as the engine operating point transition route shown in FIG.

  Next, with reference to FIG. 5, a process executed by the ECU 60 in order to realize the operation of the vehicle according to the above-described embodiment will be specifically described. FIG. 5 is a flowchart of a control process for realizing the operation of the vehicle according to the present embodiment.

  First, in step S <b> 101, the ECU 60 obtains the engine speed Ne based on the detection signal from the crank angle sensor 44 and obtains the accelerator opening Acc based on the detection signal from the accelerator opening sensor 61.

  In the subsequent step S102, the ECU 60 requires the engine after the accelerator is depressed (that is, after the engine operating point shifts) based on the engine speed Ne and the accelerator opening Acc obtained in step S101. A torque (hereinafter referred to as “target engine torque Tet” as appropriate), an engine speed (hereinafter referred to as “target engine speed Net” as appropriate) and a compression ratio (hereinafter referred to as “target compression ratio Crt” as appropriate) are calculated. Such a calculation may be performed by referring to a map having the engine torque Te, the target engine speed Ne, and the target compression ratio Cr as variables as shown in FIG. The target engine torque Tet, the target engine speed Net, and the target compression ratio Crt may be calculated based only on the accelerator opening instead of being determined based on the accelerator opening Acc and the engine speed.

  In step S103, the ECU 60 determines whether or not the shift executed when the engine operating point shifts increases the gear ratio. In other words, it is determined whether the shift is a shift-up that changes the gear ratio to a smaller value or a shift-down that changes the gear ratio to a larger value.

  When the gear shift is to increase the gear ratio (step S103: Yes), that is, when the shift is down, the ECU 60 determines whether or not the compression ratio of the engine 10 increases before and after the engine operating point shifts. (Step S104). Specifically, the ECU 60 compares the current compression ratio Cr (hereinafter referred to as “actual compression ratio Crr” as appropriate) with the target compression ratio Crt obtained in step S102. For example, a map having the engine speed, engine torque, and compression ratio as variables as shown in FIG. 3 is recorded in advance in recording means such as a memory, and the ECU 60 refers to the map to increase or decrease the compression ratio. It is good to judge.

  When the compression ratio decreases before and after the shift is executed (step S104: No), the ECU 60 determines in step S105 that the engine operating point is the target engine torque Tet, target engine speed Net and target compression obtained in step S102. The engine 10 and the continuously variable transmission 110 are controlled so that the ratio Crt is obtained. At this time, the compression ratio is changed after the shifting of the continuously variable transmission 110 is completed (step S105). That is, in order to prevent a change in engine output torque from amplifying the inertia torque and further deteriorating drivability, the compression ratio Cr is changed during a shift. This corresponds to the case where the engine operating point is shifted along the route shown in FIG. Thereafter, the ECU 60 returns this control process.

  When the compression ratio increases before and after the shift is executed (step S104: Yes), the ECU 60 determines in step S106 that the engine operating point is the target engine torque Tet, target engine speed Net, and target obtained in step S102. The engine 10 and the continuously variable transmission 110 are controlled so that the compression ratio Crt is obtained. At this time, the compression ratio is changed while the continuously variable transmission 110 is being shifted (step S106). That is, when the engine operating point is shifted along the route shown in FIG. 3 (iii), the fluctuation of the output shaft torque To can be reduced by increasing the compression ratio while the shift is being executed. Correspond. Thereafter, the ECU 60 returns this control process.

  On the other hand, when the gear shift is to reduce the gear ratio (step S103: No), that is, when the shift is up, the ECU 60 determines whether or not the compression ratio of the engine 10 decreases before and after the engine operating point shifts. (Step S107). Specifically, the ECU 60 compares the actual compression ratio Crr with the target compression ratio Crt obtained in step S102. For example, a map having the engine speed, engine torque, and compression ratio as variables as shown in FIG. 3 is recorded in advance in recording means such as a memory, and the ECU 60 refers to the map to increase or decrease the compression ratio. It is good to judge.

  When the compression ratio increases before and after the shift is executed (step S107: No), the ECU 60 performs the transition of the engine operating point by executing step S105 described above. At this time, the compression ratio is changed after the shifting of the continuously variable transmission 110 is completed (step S105). That is, in order to prevent a change in engine output torque from amplifying the inertia torque and further deteriorating drivability, the compression ratio Cr is changed during a shift. This corresponds to the case where the engine operating point is shifted along the route shown in FIG. 3 (ii). Thereafter, the ECU 60 returns this control process.

  When the compression ratio decreases before and after the shift is executed (step S107: Yes), the ECU 60 performs the transition of the engine operating point by executing step S106 described above. At this time, the compression ratio is changed while the continuously variable transmission 110 is being shifted (step S106). That is, when the engine operating point is shifted along the route shown in FIG. 3 (i), the fluctuation of the output shaft torque To can be reduced by increasing the compression ratio while the shift is being executed. Correspond. Thereafter, the ECU 60 returns this control process.

  As described above, in the vehicle according to the first embodiment, it is possible to improve the responsiveness of the behavior of the vehicle with respect to the driver's requested operation, and to reduce the shock that occurs at the time of shifting.

Second Embodiment
Next, the operation of the vehicle according to the second embodiment will be described. FIG. 6 is a flowchart of a control process for realizing the operation of the vehicle 100 according to the second embodiment. In FIG. 6, processes that are the same as those in the first embodiment are denoted by the same reference numerals.

  First, in step S <b> 101, the ECU 60 obtains the engine speed Ne based on the detection signal from the crank angle sensor 44 and obtains the accelerator opening Acc based on the detection signal from the accelerator opening sensor 61.

  In the subsequent step S102, the ECU 60 requires the engine after the accelerator is depressed (that is, after the engine operating point shifts) based on the engine speed Ne and the accelerator opening Acc obtained in step S101. A torque (hereinafter referred to as “target engine torque Tet” as appropriate), an engine speed (hereinafter referred to as “target engine speed Net” as appropriate) and a compression ratio (hereinafter referred to as “target compression ratio Crt” as appropriate) are calculated. Such a calculation may be performed by referring to a map having the engine torque Te, the target engine speed Ne, and the target compression ratio Cr as variables as shown in FIG. The target engine torque Tet, the target engine speed Net, and the target compression ratio Crt may be calculated based only on the accelerator opening instead of being determined based on the accelerator opening Acc and the engine speed. The driving force applied to the drive shaft 143 based on the target value calculated in this way is an example of “necessary driving force” according to the present invention.

  In step S201, the ECU 60 determines whether or not the amount of change in the engine speed Ne before and after the engine operating point shifts is greater than the first threshold value α. Specifically, the amount of change in the engine speed Ne is calculated by calculating the difference between the current engine speed Ne (hereinafter referred to as “actual engine speed Ner” as appropriate) and the target engine speed Net obtained in step S102. You can ask for it.

  Here, if the amount of change in the engine speed Ne before and after the engine operating point shifts increases, the inertia torque generated with the shift increases, and the compression ratio Cr is changed during the shift. Even if drivability is improved, it may be difficult to obtain a sufficient effect. The first threshold value α is defined as the amount of change in the engine speed Ne that makes it difficult to sufficiently improve drivability even when the compression ratio Cr is changed during the execution of gear shifting. It may be obtained by a theoretical or experimental method or simulation. The first threshold value α is an example of the “predetermined threshold value” according to the present invention.

  When the change amount of the engine speed Ne is larger than the first threshold value α (step S201: Yes), the ECU 60 calculates a first correction value ΔCrt1 of the target compression ratio Crt (step S202). Here, the first correction value ΔCrt1 is expected to improve drivability by changing the compression ratio Cr during the shift when the change amount of the engine speed Ne is larger than the first threshold value α. The compression ratio Cr is defined as the difference between the actual compression ratio Crr and the expected compression ratio.

  Here, a method of calculating the first correction value ΔCrt1 will be described with reference to FIG. FIG. 7 is a graph showing an example of the first correction value ΔCrt1 of the target compression ratio Crt.

  As shown in FIG. 7, the first correction value ΔCrt1 is defined to have a value when the amount of change in the engine speed Ne is larger than the first threshold value α. On the other hand, when the change amount of the engine speed Ne is equal to or smaller than the first threshold value α, sufficient drivability can be obtained without correcting the target engine speed Net by the first correction value ΔCrt1. The 1 correction value ΔCrt1 is set to zero. When the change amount of the engine speed Ne is larger than the first threshold value α, the drivability deteriorates as the change amount becomes larger. Therefore, the first correction amount ΔCrt1 is also set to increase accordingly. The Actually, it is preferable to define the first correction amount ΔCrt1 under such conditions by a theoretical, experimental method or simulation. After calculating the first correction value ΔCrt1 in this way, the ECU 60 advances the present control process to step S103.

  In step S103, the ECU 60 determines whether or not the shift executed when the engine operating point shifts increases the gear ratio. In other words, it is determined whether the shift is a shift-up that changes the gear ratio to a smaller value or a shift-down that changes the gear ratio to a larger value.

  When the gear shift is to increase the gear ratio (step S103: Yes), that is, when the shift is down, the ECU 60 determines whether or not the compression ratio of the engine 10 increases before and after the engine operating point shifts. (Step S104). Specifically, the ECU 60 compares the current compression ratio Cr (hereinafter referred to as “actual compression ratio Crr” as appropriate) with the target compression ratio Crt obtained in step S102. For example, a map having the engine speed, engine torque, and compression ratio as variables as shown in FIG. 3 is recorded in advance in recording means such as a memory, and the ECU 60 refers to the map to increase or decrease the compression ratio. It is good to judge.

  When the compression ratio decreases before and after the shift is executed (step S104: No), the ECU 60 determines in step S105 that the engine operating point is the target engine torque Tet, target engine speed Net, and target obtained in step S102. The engine 10 and the continuously variable transmission 110 are controlled so that the compression ratio Crt is obtained. At this time, the compression ratio is changed after the shifting of the continuously variable transmission 110 is completed (step S105). That is, in order to prevent a change in engine output torque from amplifying the inertia torque and further deteriorating drivability, the compression ratio Cr is changed during a shift. This corresponds to the case where the engine operating point is shifted along the route shown in FIG. Thereafter, the ECU 60 returns this control process.

  When the compression ratio increases before and after the shift is executed (step S104: Yes), the ECU 60 calculates the target compression ratio Crt again based on the following equation in step S203 (step S203).

Crt = Crt + ΔCrt1 (1)
That is, the ECU 60 resets the value obtained by adding the first correction value ΔCrt1 calculated in step S202 to the target compression ratio Crt calculated in step S201 as the target compression ratio Crt.

  Thereafter, the ECU 60 performs the transition of the engine operating point by executing step S106 described above. At this time, the compression ratio is changed while the speed change of the continuously variable transmission 110 is being executed.

  Thereafter, the ECU 60 changes the first correction value ΔCrt1 of the target compression ratio Crt based on the following equation (step S204).

ΔCrt1 = ΔCrt1-β (2)
Here, the constant β is an arbitrary positive number smaller than the first correction value ΔCrt1, and an increment for bringing the first correction value ΔCrt1 close to zero based on the equation (2) is sufficient, either a variable or a constant. May be.

  Thereafter, the ECU 60 determines whether or not the first correction value ΔCrt1 changed in step S204 is zero (step S205). Here, when the first correction value ΔCrt1 changed in step S204 is not zero (step S205: No), the ECU 60 returns the process to step S203, and repeatedly executes the above steps. That is, the first correction value ΔCrt1 is gradually decreased, and the ECU 60 performs a loop process until the target compression ratio Crt corrected in step S203 returns to the original target compression ratio Crt calculated in step S102. Then, when the first correction value ΔCrt1 changed in step S204 becomes zero (step S205: Yes), the ECU 60 ends the loop and returns to the present control process. After a series of operations relating to gear shifting is completed in this way, the corrected compression ratio Cr is returned to the original value, thereby improving the drivability while realizing the behavior of the vehicle in accordance with the driver's requested operation. Can do.

  When the shift is to reduce the shift ratio (step S103: No), that is, when the shift is up, the ECU 60 determines whether or not the compression ratio of the engine 10 decreases before and after the engine operating point shifts. (Step S107). Specifically, the ECU 60 compares the actual compression ratio Crr with the target compression ratio Crt obtained in step S102. For example, a map with the engine speed, engine torque, and compression ratio as variables as shown in FIG. 3 is recorded in advance in recording means such as a memory, and the ECU 60 refers to the map to increase or decrease the compression ratio Cr. It is good to judge.

  When the compression ratio Cr increases before and after the shift is executed (step S107: No), the ECU 60 performs the transition of the engine operating point by executing step S105 described above. At this time, the compression ratio Cr is changed after the shifting of the continuously variable transmission 110 is completed (step S105). That is, in order to prevent a change in engine output torque from amplifying the inertia torque and further deteriorating drivability, the compression ratio Cr is changed during a shift. This corresponds to the case where the engine operating point is shifted along the route shown in FIG. 3 (ii). Thereafter, the ECU 60 returns this control process.

  When the compression ratio Cr decreases before and after the shift is performed (step S107: Yes), the ECU 60 performs the transition of the engine operating point by executing the above-described step S106. At this time, the compression ratio Cr is changed while the speed change of the continuously variable transmission 110 is being executed (step S106). That is, when the engine operating point is shifted along the route shown in FIG. 3 (i), the fluctuation of the output shaft torque To can be reduced by increasing the compression ratio Cr during the shift. Corresponding to Thereafter, the ECU 60 returns this control process.

  Here, with reference to FIG. 8, the behavior of the vehicle when the engine operating point shifts along the route indicated by (i) in FIG. 3 will be described. FIG. 8 is a time chart showing changes over time in the engine speed Ne, the compression ratio Cr, and the output shaft torque To when the engine operating point shifts along the route indicated by (i) in FIG. 3 in the vehicle according to the second embodiment. It is a chart.

  FIG. 8A is a time chart showing the change over time of the engine speed Ne. The engine speed Ne is initially maintained at Ne1, and gradually decreases from time t1 at which shifting is started by the continuously variable transmission 110 as the engine operating point shifts. Thereafter, the engine speed Ne reaches Ne2 at time t4 and is kept constant. Since the vehicle 100 according to the present embodiment includes the continuously variable transmission 110 whose transmission ratio is continuously variable as a transmission, the engine speed Ne is also continuously changing.

  FIG. 8B is a time chart showing the time change of the compression ratio Cr. Here, in FIG. 8B, the solid line indicates the time change of the compression ratio Cr when the target compression ratio Crt is corrected by the first correction value ΔCrt1 in step S204 as described above, and the dotted line indicates the target in step S204. The time change of the compression ratio Cr in the comparative example which does not perform correction | amendment which concerns on the compression ratio Crt is shown. In the comparative example, except that the correction related to the target compression ratio Crt in step S204 is not performed, the same structure and control as that of the vehicle according to the present embodiment are performed. To do.

  FIG. 8C is a time chart showing a time change of the output shaft torque To of the vehicle 100 according to the present embodiment with a solid line and a time change of the output shaft torque To of the vehicle according to the comparative example with a dotted line. As shown in FIG. 8C, by performing the correction relating to the target compression ratio Crt in step S204, the fluctuation of the output shaft torque To during the shift is reduced, and drivability is more effectively achieved. Can be improved.

  As described above, in the vehicle according to the second embodiment, drivability is effectively improved by appropriately correcting the target compression ratio even when the amount of change in the engine speed at the time of shifting is large. Can do.

<Third Embodiment>
Subsequently, an operation of the vehicle according to the third embodiment will be described. FIG. 9 is a flowchart of a control process for realizing the operation of the vehicle 100 according to the third embodiment. The third embodiment is different from the second embodiment in that the processing content in step S106 is changed in the second embodiment. In addition, in FIG. 9, processes that are the same as those in the first and second embodiments described above are given the same reference numerals, and detailed descriptions thereof are omitted.

  In this embodiment, when the compression ratio decreases before and after the shift is performed (step S104: No), in step S301, the ECU 60 determines that the amount of change in the engine speed Ne obtained in step S201 is the second threshold γ. Determine if greater than. In the first and second embodiments described above, when the compression ratio decreases before and after the shift is executed (step S104: No), the drivability is further improved by changing the compression ratio after the execution of the shift is completed. However, in this embodiment, by appropriately correcting the target compression ratio Crt even in such a case, the compression ratio Cr is changed while the shift is being performed, and the drivability is improved. Can be improved. However, if the amount of change in the engine speed Ne associated with the shift increases, it is difficult to obtain a sufficient effect even if it is attempted to improve the drivability by changing the compression ratio Cr during the shift. It may become. As described above, the second threshold γ is an engine speed Ne that makes it difficult to obtain a sufficient effect even if it is attempted to improve drivability by changing the compression ratio Cr during the execution of the shift. Is defined as the amount of change. Actually, the second threshold value γ may be obtained under such conditions by a theoretical, experimental method, simulation, or the like.

  Here, a method of calculating the second threshold γ will be described with reference to FIG. FIG. 10 is a graph showing an example of the second threshold γ.

  The second threshold γ is a threshold for defining whether or not the process proceeds to step S302. When the amount of change in the engine speed Ne is larger than the second threshold value γ, a sufficient effect can be obtained even if the compression ratio Cr is changed during execution of the shift to improve drivability. Therefore, it is determined that normal processing is performed without proceeding to step S302 (that is, step S105 is executed as in the first and second embodiments).

  If the amount of change in the engine speed Ne is greater than the second threshold value γ (step S301: Yes), the ECU 60 determines in step S105 that the engine operating point is the target engine torque Tet, target engine speed Net, and A path of the actual engine operating point is set so as to achieve the target compression ratio Crt, and the actual engine operating point is shifted along the path to the target operating point. At this time, the compression ratio Cr is changed after the gear change of the continuously variable transmission 110 is completed, thereby preventing further deterioration of drivability (step S106). Thereafter, the ECU 60 returns this control process.

  On the other hand, when the change amount of the engine speed Ne is equal to or smaller than the second threshold value γ (step S301: No), the drivability is corrected by correcting the compression ratio Cr and changing it during the shift. Can be improved, the process proceeds to step S302. In step S302, the ECU 60 calculates a second correction value ΔCrt2 of the target compression ratio Crt (step S302). Here, the second correction value ΔCrt2 is expected to be equal to the actual compression ratio Cr so as to reduce the amount of change in the engine speed Ne associated with the shift by changing the compression ratio Cr during the shift. Is defined as the difference from the compression ratio Cr.

  In step S303, the ECU 60 calculates the target compression ratio Crt again based on the following equation.

Crt = Crt + ΔCrt2 (3)
That is, the ECU 60 resets a value obtained by adding the second correction value ΔCrt2 calculated in step S302 to the target compression ratio Crt calculated in step S201 as the target compression ratio Crt.

  Thereafter, in step S304, the ECU 60 sets the actual engine operating point so that the engine operating point becomes the target engine torque Tet and target engine speed Net obtained in step S102, and the target compression ratio Crt reset in step S303. And the actual engine operating point is shifted to the target operating point along the route. At this time, the compression ratio Cr is changed while the speed change of the continuously variable transmission 110 is being executed (step S304).

  Thereafter, the ECU 60 changes the correction value ΔCrt of the target compression ratio Crt based on the following equation (step S305).

ΔCrt2 = ΔCrt2-δ (4)
Here, the constant δ is an arbitrary positive number smaller than the second correction value ΔCrt2, and an increment for bringing the second correction value ΔCrt2 close to zero based on the equation (4) is sufficient, either a variable or a constant. May be.

  Thereafter, the ECU 60 determines whether or not the second correction value ΔCrt2 changed in step S305 is zero (step S306). Here, when the second correction value ΔCrt2 changed in step S305 is not zero (step S306: No), the ECU 60 returns the process to step S303 and repeatedly executes each of the above steps. That is, the second correction value ΔCrt2 is gradually changed, and the ECU 60 performs a loop process until the target compression ratio Crt corrected in step S306 returns to the original target compression ratio Crt calculated in step S102. And when the 2nd correction value (DELTA) Crt2 changed in step S305 became zero (step S306: Yes), ECU60 complete | finishes the said loop, and returns this control process.

  Here, with reference to FIG. 11, the behavior of the vehicle when the engine operating point shifts along the route indicated by (ii) in FIG. 3 will be described. FIG. 11 shows the engine speed Ne, the compression ratio Cr, the second correction value ΔCrt2, and the output shaft torque To when the engine operating point shifts along the route indicated by (ii) in FIG. 3 in the vehicle according to the third embodiment. It is a time chart which shows the time change of.

  FIG. 11A is a time chart showing the change over time of the engine speed Ne. The engine speed Ne is initially maintained at Ne1, and gradually decreases from time t1 at which shifting is started by the continuously variable transmission 110 as the engine operating point shifts. Thereafter, the engine speed Ne reaches Ne2 at time t4 and is kept constant. Since the vehicle 100 according to the present embodiment includes the continuously variable transmission 110 whose transmission ratio is continuously variable as a transmission, the engine speed Ne is also continuously changing.

  FIG. 4B is a time chart showing the time change of the compression ratio Cr. The compression ratio Cr is initially maintained at Cr2, and gradually increases from time t2 as the engine operating point shifts. Thereafter, it reaches Cr1 at time t3 and is kept constant. Here, the period during which the compression ratio Cr changes (ie, the period from t2 to t3) is included in the period during which the engine speed Ne changes (ie, the period from t1 to t4). In other words, the compression ratio Cr is controlled by the ECU 60 so that the compression ratio Cr changes while the gear is being changed by the continuously variable transmission 110.

  FIG. 11C shows a time change of the second correction value ΔCrt2. In the present embodiment, the second correction value ΔCrt2 is set so as to reduce fluctuations in the output shaft torque To during the period in which the compression ratio is changed. The second correction value ΔCrt2 is set to zero in a period during which the compression ratio Cr is kept unchanged (that is, a period before time t2 and after time t3), and a period during which the compression ratio Cr changes (that is, It is set to have a finite value during the period from time t2 to t3.

  FIG. 11D is a time chart showing a time change of the output shaft torque To of the vehicle 100 according to the present embodiment by a solid line and a time change of the output shaft torque To of the vehicle according to the comparative example by a dotted line. As shown in FIG. 8D, by providing the second correction value ΔCrt2 for the target compression ratio Crt, it is possible to more effectively improve the drivability at the time of shifting while reducing the fluctuation of the output shaft torque To. it can.

  As described above, in the vehicle according to the third embodiment, even when the compression ratio is changed after the shift is completed in the first and second embodiments, the compression ratio is corrected during the shift. Thus, the change in the drive shaft torque that occurs at the time of shifting can be reduced, and the responsiveness of the vehicle to the driver's requested operation can be improved.

  The present invention is not limited to the above-described embodiments, and can be changed as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. Is also included in the technical scope of the present invention.

  The present invention can be used for a control device of a vehicle such as an automobile equipped with an engine.

  10 engine, 60 ECU, 61 accelerator opening sensor, 100 vehicle, 110 continuously variable transmission

Claims (4)

A vehicle equipped with an engine capable of changing a compression ratio indicating the degree of compression of an air-fuel mixture, and a transmission means having a variable rotational speed ratio between an output shaft of the engine and an output member connected to the axle. A control device,
When the required driving force of the vehicle changes, the actual engine operating point that is the actual engine operating point is shifted from the engine operating point before the change to the target engine operating point that is the engine operating point corresponding to the changed required driving force. Control means;
A compression ratio changing means for changing the compression ratio in accordance with the transition of the actual engine operating point;
The compression ratio at the target operating point is set lower than the engine operating point before the required driving force changes, and the rotational speed ratio at the target operating point is lower than the engine operating point before the required driving force changes. The vehicle control apparatus according to claim 1, wherein the compression ratio changing unit changes the compression ratio while the control unit is changing the rotation speed ratio when it is set to be small. A vehicle equipped with an engine capable of changing a compression ratio indicating the degree of compression of an air-fuel mixture, and a transmission means having a variable rotational speed ratio between an output shaft of the engine and an output member connected to the axle. A control device,
When the required driving force of the vehicle changes, the actual engine operating point that is the actual engine operating point is shifted from the engine operating point before the change to the target engine operating point that is the engine operating point corresponding to the changed required driving force. Control means;
A compression ratio changing means for changing the compression ratio in accordance with the transition of the actual engine operating point;
The compression ratio at the target operating point is set larger than the engine operating point before the required driving force changes, and the rotational speed ratio at the target operating point is higher than the engine operating point before the required driving force changes. The control apparatus for a vehicle according to claim 1, wherein the compression ratio changing means changes the compression ratio while the control means is changing the rotation speed ratio when it is set to be large. A correction means for correcting the compression ratio at the target operating point when the amount of change in the engine speed before and after the transition of the actual engine operating point is greater than a predetermined threshold;
The compression ratio changing means changes the compression ratio to the corrected compression ratio while the control means is changing the rotation speed ratio. Vehicle control device. The correction means sets the compression ratio to the compression ratio before the correction after the transition of the actual engine operating point is completed,
4. The vehicle control device according to claim 3, wherein the compression ratio changing unit changes the compression ratio so that the compression ratio becomes the compression ratio before the correction.

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