JP2009092176A - Shift controller of vehicular continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excellent acceleration feeling adjusted to a request of a driver even in short-time acceleration such as urban district travel and long-time acceleration such as a superhighway, in an acceleration shifting mode of controlling a shift so as to increase an input shaft rotating speed according to a vehicle speed increase. <P>SOLUTION: In the acceleration shifting mode, when reaching predetermined switching timing (a point C), an increase rate to an increase in a vehicle speed V is reduced. Thus, when relatively largely setting the increase rate before reaching the switching timing (the point C), the excellent acceleration performance of high acceleration is provided. While providing the excellent acceleration feeling of the high acceleration in the short-time acceleration such as the urban district travel, since the increase rate is reduced when reaching the switching timing (the point C), acceleration can be smoothly performed while continuously shifting up to a high vehicle speed without making a target rotating speed NINT reach an upper limit value NINTmax, and a smooth and elongating acceleration feeling can be provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a shift control device for a continuously variable transmission for a vehicle, and more particularly, to a shift control device having an acceleration shift mode for performing shift control so that an input shaft rotation speed increases in response to an increase in vehicle speed when a high acceleration is requested. It is about improvement.

  There has been proposed a shift control device for a continuously variable transmission for a vehicle having an acceleration shift mode for performing a shift control so that an input shaft rotational speed increases in response to a rise in vehicle speed when a driver demands high acceleration. . The shift control device described in Patent Document 1 is an example, and the acceleration shift mode and the normal shift mode can be switched based on the accelerator operation amount representing the acceleration request value. To limit the increase of the input shaft rotation speed according to the amount, the shift control is performed so that the input shaft rotation speed increases at a constant increase rate as the vehicle speed increases, so that excellent acceleration feeling can be obtained It has become. That is, when the accelerator operation amount becomes large due to an acceleration request (when kicking down), the input shaft rotation speed and further the prime mover rotation speed are increased at a stretch to the target rotation speed determined according to the accelerator operation amount. Then, it takes time to increase and the responsiveness until the vehicle speed increases is poor. On the other hand, after the input shaft rotational speed reaches the target rotational speed, the rotational speed is maintained and the gear ratio decreases as the vehicle speed increases. (Upshifting), the prime mover is noisy and the ride is not good and the acceleration feeling is not always good.

Further, in Patent Document 1, when the input shaft rotational speed increases due to the increase in vehicle speed and the input shaft rotational speed reaches an upper limit value determined according to the accelerator operation amount, the input shaft rotational speed is reduced by upshifting, After that, the input shaft rotation speed is increased at a constant rate in accordance with the increase of the vehicle speed, and the acceleration feeling similar to that of the stepped transmission can be obtained. On the other hand, in Patent Document 2, as in Patent Document 1, the increase in the input shaft rotation speed is limited according to the accelerator operation amount, and the shift control is performed so that the input shaft rotation speed increases as the vehicle speed increases. However, the increase rate is gradually reduced according to the vehicle speed deviation (difference between the look-ahead vehicle speed corresponding to the accelerator operation amount and the actual vehicle speed), and although the instantaneous acceleration performance is inferior to that of Patent Document 1, Shift control is smoothly performed up to the vehicle speed, and excellent ride comfort is obtained.
JP 2004-125072 A JP 2004-162800 A

  By the way, the acceleration feeling required by the driver is different between short-time acceleration in urban areas and the like and long-time acceleration on highways and the like. In short-time acceleration, the input shaft rotation speed is increased with increasing vehicle speed as in Patent Document 1. Furthermore, while a high acceleration acceleration feeling in which the motor rotational speed increases proportionally is desired, in the case of long-time acceleration, acceleration with a smooth extension that continuously accelerates to a high vehicle speed as in Patent Document 2. Feeling is desired. That is, in the apparatus described in Patent Document 1, a shift shock such as a stepped transmission occurs during long-time acceleration, and a smooth acceleration feeling cannot be obtained, whereas in the apparatus described in Patent Document 2, acceleration is performed for a short time. However, it is difficult to obtain a high acceleration acceleration feeling that is sufficiently satisfactory.

  FIG. 10 is a diagram showing the relationship between the vehicle speed V and the target rotational speed NINT of the input shaft rotational speed. In the case of the comparative example 1 indicated by a broken line, the target rotational speed NINT with respect to the increase in the vehicle speed V as in Patent Document 1 is shown. Shift control is performed so as to increase at a constant increase rate, but when the input shaft rotation speed reaches a predetermined upper limit value NINTmax, the upper limit value NINTmax is maintained, and the upper limit value NINTmax is reached. Up to the above, excellent acceleration performance can be obtained, but acceleration performance and acceleration feeling after reaching the upper limit value NINTmax are not necessarily good. For this reason, it is effective for short-time acceleration in urban areas and the like, but long-time acceleration on highways and the like is not always satisfactory. In Patent Document 1, when the input shaft rotational speed reaches the upper limit value NINTmax, it is reduced by an upshift, so that an excellent acceleration performance is obtained, but a shift shock similar to that of a stepped transmission occurs, so an expressway or the like Long-term acceleration is not always satisfactory.

  On the other hand, in Comparative Example 2 indicated by the alternate long and short dash line in FIG. 10, the shift control is performed so that the target rotational speed NINT increases at a constant increase rate with respect to the increase in the vehicle speed V, as in Comparative Example 1. Although the ratio is relatively small and the acceleration feeling of high acceleration is inferior to that of Comparative Example 1, the input shaft rotation speed can be continuously accelerated to a high vehicle speed without reaching the upper limit value NINTmax, and there is a smooth extension. Acceleration feeling is obtained. For this reason, it is effective for long-time acceleration on a highway or the like, but short-time acceleration such as traveling in an urban area is not always satisfactory.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to reduce the speed of driving in an urban area in the acceleration shift mode in which the shift control is performed so that the input shaft rotation speed increases in accordance with the increase in the vehicle speed. An object is to obtain an excellent acceleration feeling that meets the demands of the driver, whether it is time acceleration or long time acceleration on a highway or the like.

  In order to achieve such an object, the first invention is for a vehicle having an acceleration shift mode in which a shift control is performed so that an input shaft rotation speed increases in response to an increase in vehicle speed when a high acceleration request is demanded by a driver. In a transmission control device for a continuously variable transmission, at a predetermined switching timing before the input shaft rotation speed reaches a predetermined upper limit value, the input shaft rotation against the increase in the vehicle speed without decreasing the input shaft rotation speed. The speed increase rate is reduced.

  According to a second aspect of the present invention, in the transmission control device for a continuously variable transmission for a vehicle according to the first aspect of the invention, (a) a vehicle speed change correction value that defines an increase rate of the input shaft rotational speed with respect to an increase in the vehicle speed in the acceleration shift mode (B) increase rate switching means for switching the vehicle speed change correction value so that the increase rate of the input shaft rotation speed with respect to the increase in the vehicle speed is reduced, and (c) the acceleration shift. Elapsed time of speed change control by mode, increase width of the vehicle speed, increase width of the input shaft rotation speed, rotation speed difference from the input shaft rotation speed to the upper limit value, and change in driver's accelerator operation amount Switching timing determination means for determining the switching timing by using one of them.

  In such a transmission control device for a continuously variable transmission for a vehicle, the input shaft rotation speed is set to a predetermined upper limit in the acceleration shift mode in which the shift control is performed so that the input shaft rotation speed increases as the vehicle speed increases. When the predetermined switching timing before reaching the value is reached, the increase rate of the input shaft rotation speed with respect to the increase in vehicle speed is reduced without reducing the input shaft rotation speed, so the increase rate before reaching the switching timing is compared. It is possible to obtain excellent acceleration performance with high acceleration by setting it to a large size, and high acceleration acceleration feeling that meets the driver's requirements can be obtained in short-time acceleration such as urban driving You can On the other hand, since the rate of increase is reduced when the switching timing is reached, the input shaft rotation speed does not reach the upper limit value and can be smoothly accelerated while continuously shifting to a high vehicle speed. In acceleration, it is possible to obtain a smooth and long acceleration feeling that meets the driver's requirements.

  In the second aspect of the invention, the elapsed time of the shift control in the acceleration shift mode, the vehicle speed increase width, the input shaft rotation speed increase width, the rotation speed difference from the input shaft rotation speed to the upper limit value, and the change in the driver's accelerator operation amount Since the switching timing is determined using at least one of the above, it is possible to obtain an acceleration feeling that matches the driver's request. That is, when the elapsed time of the shift control in the acceleration shift mode becomes a predetermined value or more, when the increase speed of the vehicle speed becomes a predetermined value or more, or when the increase width of the input shaft rotation speed becomes a predetermined value or more. The acceleration demand time is considered to be long and demands long-term acceleration.Therefore, by reducing the rate of increase of the input shaft rotation speed, the acceleration fee has a smooth extension that meets the driver's requirements. A ring will be obtained. Also, if the difference in rotational speed from the input shaft rotational speed to the upper limit is less than or equal to the predetermined value, the input shaft rotational speed will change and the acceleration performance will be impaired if the upper limit is reached. By making the increase rate of the small, a good acceleration feeling can be maintained. In addition, if the amount of accelerator operation by the driver decreases, the rate of increase in the input shaft rotation speed should be reduced because the degree of demand for high acceleration is low and it is considered that smooth acceleration is required. Thus, an acceleration feeling that meets the driver's requirements can be obtained.

  A continuously variable transmission is a transmission that can change a transmission gear ratio steplessly. A variable pulley having a variable V groove width, that is, a variable effective diameter, is wound around the pair of variable pulleys. A belt type continuously variable transmission of a type in which the gear ratio is continuously changed by reciprocally changing the effective diameter of the pair of variable pulleys. A pair of cone members arranged concentrically and relatively rotatably, and a plurality of rollers arranged in a sandwiched state between them, and the rotation axis of the rollers is the rotation axis of the pair of cone members The present invention can be applied to transmission control devices for various continuously variable transmissions such as a toroidal continuously variable transmission of a type in which the transmission gear ratio is continuously changed by being rotated in a plane including the same.

  When the input shaft rotation speed changes due to the speed change control of the continuously variable transmission, the rotation speed of the prime mover for driving the vehicle is also changed accordingly. However, the type of the prime mover is not particularly limited, and the combustion of the fuel Gasoline engines and diesel engines that generate power, and electric motors that are driven to rotate by electric energy are widely used. However, the present invention can also be applied to hybrid vehicles that include a plurality of types of prime movers.

  Whether or not the driver's acceleration request is a high acceleration request depends on the acceleration request value indicating the amount of output that the driver requests from the vehicle, that is, the accelerator pedal operation amount (accelerator operation amount) and the accelerator operation amount. The throttle valve opening controlled by the engine, the fuel injection amount indicating the amount of fuel injected into a chamber or cylinder provided in the intake pipe of the engine, the intake air amount sucked through the intake pipe of the engine, etc. are predetermined. It can be determined by whether or not the value is greater than or equal to the value, or whether or not the rate of change is greater than or equal to a predetermined value.

  When it is determined whether or not a high acceleration request is made depending on whether or not the acceleration request value is equal to or greater than a predetermined acceleration request determination value, whether the acceleration is desired or not depends on the vehicle speed. It is desirable to set the determination value using as a parameter a physical quantity having a certain relationship with the vehicle speed. The same applies when using an acceleration request value other than the accelerator operation amount. Further, since the road surface gradient also affects the accelerator operation amount and affects the determination of whether or not acceleration is desired, the acceleration request determination value can be determined in consideration of the road surface gradient in addition to the vehicle speed.

  In addition to the acceleration shift mode, a normal shift mode is usually provided. The normal shift mode is obtained in accordance with a normal shift condition determined by, for example, an accelerator operation amount (corresponding to an output request amount) and a vehicle speed as parameters. If the accelerator operation amount suddenly increases due to an acceleration request, the target rotation speed is increased at a stretch and input is performed. The shaft rotation speed and further the rotation speed of the prime mover can be increased at once, but it may take time to increase the rotation speed and the response to the increase in vehicle speed may be poor, and the prime mover is maintained in a high rotation state. Since the gear ratio is reduced (upshifted) as the vehicle speed increases, the noise is loud and the riding comfort is poor, and the acceleration feeling is not necessarily good. For this reason, when acceleration is requested, the shift control is performed in an acceleration shift mode different from the normal shift mode.

  Here, since the vehicle speed (output shaft rotational speed) does not change suddenly, it can be considered constant in the shift control, and the input shaft rotational speed is the speed ratio of the continuously variable transmission (input shaft rotational speed / output). It is also possible to use the gear ratio as a shift control amount instead of the input shaft rotation speed and to perform the shift control by obtaining the target gear ratio instead of the target rotation speed. This is the same in the acceleration shift mode. As a result, the shift control may be performed so that the input shaft rotation speed is increased at a predetermined increase rate as the vehicle speed increases.

  The acceleration shift mode performs shift control superior in acceleration performance, acceleration feeling, noise, and the like as compared with a case where the shift control in the normal shift mode is used as it is. For example, after limiting the increase in the input shaft rotation speed corresponding to the accelerator operation amount, that is, the rotation speed of the prime mover in the normal shift mode and increasing the input shaft rotation speed to a predetermined initial value determined according to the acceleration request value etc. The speed change control is configured so that the input shaft rotational speed increases in proportion to the increase in the vehicle speed. However, it is not always necessary to make it completely proportional to the vehicle speed, that is, the speed ratio need not be constant. The input shaft rotation speed may be increased by multiplying the vehicle speed change by a predetermined coefficient.

  The acceleration shift mode is configured to perform shift control using a vehicle speed change correction value that defines an increase rate of the input shaft rotational speed with respect to an increase in the vehicle speed, for example. When the predetermined switching timing is reached, the increase rate is small. The vehicle speed change correction value may be switched so that The vehicle speed change correction value is obtained, for example, by sequentially adding a value obtained by multiplying the change speed ΔV of the vehicle speed V by a predetermined correction coefficient α, and changing the value of the correction coefficient α may change the increase rate. it can. It is also possible to obtain the vehicle speed change correction value from a predetermined map using the change speed ΔV as a parameter. In this case, two types of maps with different increase rates may be prepared in advance.

  The change in the increase rate of the input shaft rotation speed with respect to the increase in the vehicle speed can be performed by switching the vehicle speed change correction value as described above. For example, two types of acceleration shift modes having different correction coefficients α are prepared. Various modes are possible such as switching the acceleration shift mode. The increase rate switching means of the second invention includes not only switching the vehicle speed change correction value itself by the correction coefficient α, but also switching between two types of acceleration shift modes having different vehicle speed change correction values.

  The rate of increase of the input shaft rotation speed with respect to the increase in vehicle speed is constant before and after the switching timing, that is, it changes linearly with respect to the increase in vehicle speed, and the change gradient (change rate) may be switched. It is also possible to change non-linearly as in Document 2. Before reaching the switching timing, the rate of increase is constant, and the input shaft rotation speed is linearly changed as the vehicle speed increases. When the switching timing is reached, the rate of increase is continuously reduced and input when the vehicle speed increases. Various modes are possible, such as performing shift control so that the shaft rotation speed can be changed nonlinearly. The change in the input shaft rotation speed is only for the increase in the vehicle speed. If the increase rate of the vehicle speed changes with time, the increase rate of the input shaft rotation speed also changes with time, and the increase in vehicle speed Even if the increase rate is constant, it does not mean that the input shaft rotation speed changes linearly in a time chart or the like.

  The switching timing for reducing the increasing rate of the input shaft rotation speed may be at least before the input shaft rotation speed reaches a predetermined upper limit value. This upper limit value may be determined based on, for example, the maximum rotational speed of the prime mover, assuming that the accelerator operation amount is maximum, but in consideration of the case where the accelerator operation amount is not maximum, The accelerator operation amount, that is, the driver's output request amount may be set by a predetermined map or the like as a parameter.

  The above switching timing is basically for determining whether or not the current acceleration request is for a long time acceleration on an expressway or the like. For example, when the elapsed time of the shift control in the acceleration shift mode exceeds a predetermined value If the vehicle speed increase exceeds a predetermined value, or if the input shaft rotation speed increase exceeds a predetermined value, it is considered that the acceleration request time is long and long time acceleration is required. Therefore, it is desirable to switch so that the increase rate of the input shaft rotation speed becomes small. Although the switching timing may be determined based on any one of these, it is desirable to determine by determining a plurality of conditions. Other rotational speeds having a fixed relationship with the vehicle speed and the input shaft rotational speed can be used, but are substantially the same.

  In addition, if the difference in rotational speed from the input shaft rotational speed to the upper limit value is less than or equal to the predetermined value, the input shaft rotational speed will change and the acceleration feeling will be lost if the input shaft rotational speed reaches the upper limit value. It is desirable to maintain a good acceleration feeling by switching so that the rate of increase in speed is small. When the driver's accelerator operation amount (requested output amount) decreases, it is considered that the demand for high acceleration is low and acceleration with smooth extension is required. It is desirable to switch so that the ratio is small. Therefore, it is desirable to add these conditions to the determination condition for the switching timing.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a skeleton diagram of a vehicle drive device 10 to which the present invention is applied. The vehicle drive device 10 is of a horizontal type and is suitably employed in an FF (front engine / front drive) type vehicle. A gasoline engine or diesel engine that is an internal combustion engine is used as a driving source (motor) for traveling. The engine 12 is provided. The output of the engine 12 is transmitted from the torque converter 14 to the differential gear device 22 via the forward / reverse switching device 16, the belt-type continuously variable transmission (CVT) 18, and the reduction gear mechanism 20, and the left and right drive wheels 24L, Distributed to 24R.

  The torque converter 14 corresponds to a fluid transmission device, and includes a pump impeller 14p connected to the crankshaft of the engine 12 and a turbine impeller 14t connected to the forward / reverse switching device 16 via the turbine shaft 34. The power is transmitted through the fluid. Further, a lock-up clutch 26 is provided between the pump impeller 14p and the turbine impeller 14t so that they can be integrally connected to rotate integrally. The pump impeller 14p is used to control the transmission of the continuously variable transmission 18, generate belt clamping pressure, control the engagement of the lock-up clutch 26, or supply lubricating oil to each part. A mechanical oil pump 28 that generates hydraulic pressure is provided.

  The forward / reverse switching device 16 is composed of a double pinion type planetary gear device. The turbine shaft 34 of the torque converter 14 is connected to the sun gear 16s, and the input shaft 36 of the continuously variable transmission 18 is connected to the carrier 16c. ing. Then, when the forward clutch C1 disposed between the carrier 16c and the sun gear 16s is engaged, the forward / reverse switching device 16 is integrally rotated so that the turbine shaft 34 is directly connected to the input shaft 36, and the forward direction. Is transmitted to the drive wheels 24R, 24L. When the reverse brake B1 disposed between the ring gear 16r and the housing 30 is engaged and the forward clutch C1 is released, the input shaft 36 is reversely rotated with respect to the turbine shaft 34. The driving force in the reverse direction is transmitted to the drive wheels 24R and 24L.

  The continuously variable transmission 18 includes a primary sheave (input-side variable pulley) 38 having a variable effective diameter provided on the input shaft 36 and a secondary sheave (output-side variable pulley) having a variable effective diameter provided on the output shaft 40. ) 42 and a transmission belt 44 wound around the primary sheave 38 and the secondary sheave 42, and power is transmitted through frictional force between the sheaves 38 and 42 and the transmission belt 44. Is called. The primary sheave 38 and the secondary sheave 42 each have a variable V-groove width and are configured to include hydraulic cylinders 38 s and 42 s. The hydraulic pressure (primary sheave pressure) Pin of the hydraulic cylinder 38 s of the primary sheave 38 is changed to the speed change control circuit 50 ( 2), the V-groove width of the sheaves 38 and 42 is changed to change the engagement diameter (effective diameter) of the transmission belt 44, and the gear ratio γ (= input shaft rotational speed NIN / output). The shaft rotation speed NOUT) is continuously changed. Further, the hydraulic pressure (secondary sheave pressure) Pout of the hydraulic cylinder 42s of the secondary sheave 42 is pressure-controlled by the clamping pressure control circuit 70 (see FIG. 2) so that the transmission belt 44 does not slip. The shift control circuit 50 and the clamping pressure control circuit 70 are, for example, a linear solenoid valve or a duty solenoid valve whose output hydraulic pressure is continuously controlled by the electronic control unit 80 shown in FIG. It has a control valve for regulating the pressure of the sheave pressure Pin and the secondary sheave pressure Pout.

  In FIG. 2, the electronic control unit 80 is configured to include a microcomputer, and performs signal processing according to a program stored in advance in the ROM while utilizing the temporary storage function of the RAM, thereby changing the speed of the continuously variable transmission 18. It performs control, clamping pressure control, output control of the engine 12, and the like, and is configured separately for engine control, CVT control, etc. as necessary. A shift position sensor 82, an accelerator operation amount sensor 84, an engine rotation speed sensor 86, a vehicle speed sensor 88, an input shaft rotation speed sensor 90, and the like are connected to the electronic control unit 80, the shift position SFTP of the shift lever 81, and the accelerator pedal 83. The operation amount (accelerator operation amount) PAP, the engine rotation speed NE, the vehicle speed V (corresponding to the rotation speed (output shaft rotation speed) NOUT of the output shaft 40), the input shaft rotation speed NIN (rotation speed of the input shaft 36), etc. Signals representing various information necessary for various controls are supplied. The accelerator pedal 83 is an output request operation member that is operated in response to the driver's output request. The accelerator operation amount PAP represents the output request amount, and corresponds to an acceleration request value in this embodiment. The hydraulic control circuit 32 performs a line pressure control circuit that controls the line pressure PL, an engagement release control of the lockup clutch 26, a slip control, etc., in addition to the shift control circuit 50 and the clamping pressure control circuit 70. A lock-up clutch control circuit is provided.

  FIG. 3 is a block diagram for explaining various functions that the electronic control unit 80 has for the shift control of the continuously variable transmission 18. The shift control means 100 includes a shift mode switching means 102, a normal shift means 104, And a linear shift means 110. The normal speed change means 104 performs speed change control in the normal speed change mode, the linear shift means 110 performs speed change control in the acceleration speed change mode, and the speed change mode switching means 102 is the normal speed change means in response to the driver's acceleration request. A normal shift mode by 104 and an acceleration shift mode by the linear shift means 110 are switched. The linear shift unit 110 that performs shift control in the acceleration shift mode is an acceleration shift unit.

  The shift control in the normal shift mode executed by the normal shift means 104 will be described in detail. For example, as shown in FIG. 4, the target on the input side is determined from a shift map determined in advance using the accelerator operation amount PAP and the vehicle speed V as parameters. The rotation speed NINT is calculated, and the duty ratio of the duty solenoid valve of the speed change control circuit 50 or the linear solenoid valve is set according to the deviation or the like so that the actual input shaft rotation speed NIN matches the target rotation speed NINT. Feedback control of the drive current and the like is performed to control the supply and discharge of hydraulic oil to and from the hydraulic cylinder 38s of the primary sheave 38. The map in FIG. 4 corresponds to the normal speed change condition, and a target rotational speed NINT that sets a larger speed ratio γ as the vehicle speed V is smaller and the accelerator operation amount PAP is larger is set. Further, since the vehicle speed V corresponds to the output shaft rotational speed NOUT, the target rotational speed NINT, which is the target value of the input shaft rotational speed NIN, corresponds to the target speed ratio, and the minimum speed ratio γmin of the continuously variable transmission 18 and the maximum speed change. It is determined within the range of the ratio γmax. The shift map is stored in advance in a map storage device (storage means such as a ROM) 94 of the electronic control unit 80. Instead of using the accelerator operation amount PAP as it is, it is also possible to set the shift map using a driver's required output (power) determined in consideration of the vehicle speed V or the like as a parameter.

  Here, in such a normal speed change mode, when the accelerator operation amount PAP suddenly increases due to the driver's acceleration request, the target rotational speed NINT is increased at a stretch, the input shaft rotational speed NIN, and further the engine 12. However, the responsiveness until the vehicle speed V begins to increase due to the time required for the engine speed NE to increase is poor. Further, after the engine 12 reaches a high speed, the engine 12 is maintained in the high speed state, and the gear ratio γ is smoothly reduced (upshifted) as the vehicle speed V increases. Not only is it bad, but the acceleration feeling is not always good either. For this reason, when an acceleration request is considered that the driver wants a predetermined acceleration, the shift mode switching unit 102 switches to the shift control by the linear shift unit 110, and the shift control is performed in an acceleration shift mode suitable for acceleration traveling. Done.

  The shift mode switching means 102 that switches the shift mode in response to the acceleration request determines, for example, whether or not the acceleration is requested by performing signal processing according to the flowchart of FIG. 5, and switches the shift mode. FIG. 5 is repeatedly executed at a predetermined cycle time. In step S1, an acceleration request determination value PAPL for determining whether or not an acceleration request is made is set based on the accelerator operation amount PAP. Specifically, as shown in FIG. 6, an acceleration request determination value PAPL is set according to the actual vehicle speed V from a map determined in advance with the vehicle speed V as a parameter. That is, when the vehicle speed V increases, the accelerator operation amount PAP increases even when acceleration is not desired. Therefore, in the acceleration request determination value map, the acceleration request determination value PAPL increases as the vehicle speed V increases with the vehicle speed V as a parameter. It is set to be. The map related to the acceleration request determination value PAPL in FIG. 6 is stored in advance in the map storage device 94 of the electronic control unit 80 in the same manner as the shift map in FIG.

  Returning to FIG. 5, in step S2, the acceleration request determination value PAPL is compared with the actual accelerator operation amount PAP. If PAP <PAPL, it is determined that the driver does not want to accelerate. In step S3, the normal transmission mode is selected, and the normal transmission unit 104 is caused to execute the shift control. On the other hand, if PAP ≧ PAPL. If it is determined that the driver wants acceleration, an acceleration shift mode is selected in step S4, and the linear shift means 110 is caused to execute shift control.

The shift control in the acceleration shift mode executed by the linear shift means 110 will be specifically described. First, as shown in the following equation (1), the target rotational speed reference value NINTLB, the accelerator depression correction value NINTLPAP, and the vehicle speed change correction value NINTLSPD Are added to calculate the target rotational speed NINT. As shown in FIG. 7, the target rotational speed reference value NINTLB is set by a map or an arithmetic expression using the vehicle speed V as a parameter, and is determined so that the smaller the vehicle speed V, the larger the gear ratio γ. The target rotational speed reference value NINTLB is the same value as the target rotational speed NINT obtained according to the shift map of FIG. 4 with the acceleration request determination value PAPL as the accelerator operation amount PAP, and becomes the reference value for the acceleration shift mode. While the shift control is continued in the series of acceleration shift modes, the constant value obtained first when the shift to the acceleration shift mode is performed is used as it is. That is, even when the accelerator pedal 83 is depressed with a full stroke (opening degree: 100%), the target rotational speed according to FIG. 7 depends on the vehicle speed V when the accelerator operation amount PAP exceeds the acceleration request determination value PAPL. A reference value NINTLB is determined, and the target rotational speed reference value NINTLB is a relatively low value that matches the target rotational speed NINT obtained according to the shift map of FIG. 4 according to the acceleration request determination value PAPL, and the target rotational speed reference The shift control in the acceleration shift mode is executed with the value NINTLB as a reference.
NINT = NINTLB + NINTLPAP + NINTLSPD (1)

  FIG. 10 is a diagram for specifically explaining an example of the shift control in the acceleration shift mode executed by the linear shift means 110. Like the shift map of FIG. 4, the change in the target rotational speed NINT using the vehicle speed V as a parameter. That is, the change in the transmission gear ratio γ is shown. Point A in FIG. 10 indicates the target rotational speed NINT when the determination in step S2 in FIG. 5 is YES (positive) and the mode is switched from the normal speed change mode to the acceleration speed change mode (or just before), that is, in FIG. The target rotational speed NINT determined according to the vehicle speed V and the accelerator operation amount PAP (acceleration request determination value PAPL) according to the map matches the target rotational speed reference value NINTLB in the above equation (1).

The accelerator depression correction value NINTLPAP is a correction value for increasing the target rotational speed NINT as the accelerator operation amount PAP, that is, the acceleration request value is larger. For example, as shown in FIG. 8, the accelerator operation amount PAP is predetermined as a parameter. It is obtained according to the map and arithmetic expression. The vehicle speed change correction value NINTLSPD is a correction value for increasing the target rotational speed NINT, that is, the input shaft rotational speed NIN at a constant increase rate with respect to the increase in the vehicle speed V. For example, as shown in the following equation (2): The value obtained by multiplying the change rate ΔV of the vehicle speed V or the change amount ΔV of the vehicle speed V per cycle time by a predetermined correction coefficient α is added to the previous correction value NINTLSPD _i−1 . Since the vehicle speed V does not change abruptly, the vehicle speed change correction value NINTLSPD = 0 at the time of switching to the acceleration shift mode, and the target rotational speed NINT obtained according to the above equation (1) is accelerated to the target rotational speed reference value NINTLB. This is a value obtained by adding the depression correction value NINTLPAP. Point B in FIG. 10 is downshifted from point A to point B at a stroke at the target rotational speed NINT at this time.
NINTLSPD _i = NINTLSPD _i-1 + α × ΔV (2)

  On the other hand, when downshifted to the point B, the driving force of the vehicle is increased and the vehicle is accelerated, and the vehicle speed change correction value NINTLSPD increases at a constant increase rate determined by the correction coefficient α according to the vehicle speed change ΔV. To do. As a result, the target rotational speed NINT obtained according to the equation (1) is also increased at a constant rate of increase with respect to the vehicle speed change ΔV, and is linear with respect to the vehicle speed V as shown by points B to C in FIG. Can be increased. The accelerator depression correction value NINTLPAP and the vehicle speed change correction value NINTLSPD are sequentially updated every time the target rotational speed NINT is calculated at a predetermined cycle time during the shift control process in a series of acceleration shift modes, and the vehicle speed change correction is performed. The value NINTLSPD is continuously increased as the vehicle speed V increases. The map relating to the accelerator depression correction value NINTLPAP in FIG. 8 and the map relating to the target rotational speed reference value NINTLB in FIG. 7 are stored in advance in the map storage device 94 of the electronic control unit 80, similarly to the shift map in FIG. .

  Then, when the target rotational speed NINT is obtained in accordance with the equation (1) in this way, as in the normal shift mode, the deviation or the like thereof is set so that the actual input shaft rotational speed NIN matches the target rotational speed NINT. In response to this, feedback control of the duty ratio of the duty solenoid valve of the shift control circuit 50 or the drive current of the linear solenoid valve is performed to control the supply and discharge of hydraulic fluid to the hydraulic cylinder 38s of the primary sheave 38. The final target rotational speed NINT is guarded so as not to exceed a predetermined upper limit value NINTmax determined in advance based on the maximum rotational speed of the engine 12 or the like. Further, the target rotational speed NINT and the actual input shaft rotational speed NIN are not exactly the same, but the input shaft rotational speed NIN can be changed following the target rotational speed NINT, so that response delay is a problem. If this is not the case, the target rotation speed NINT can be regarded as the input shaft rotation NIN.

  Here, the gradient (increase rate) of the target rotational speed NINT with respect to the vehicle speed change ΔV varies depending on the correction coefficient α when calculating the vehicle speed change correction value NINTLSPD. For example, when the correction coefficient α is relatively large, FIG. As in Comparative Example 1 indicated by a broken line, the gradient of the target rotational speed NINT is also relatively large, and excellent acceleration performance with high acceleration can be obtained. However, when the target rotational speed NINT increases and reaches the upper limit value NINTmax, the upshift is continuously performed as the vehicle speed V increases while sticking to the upper limit value NINTmax. Acceleration feeling decreases. Therefore, short-time acceleration, such as in urban areas, provides an excellent acceleration feeling with high acceleration, but long-term acceleration, such as on a highway that accelerates to a high vehicle speed, does not necessarily provide a satisfactory acceleration feeling. .

  On the other hand, Comparative Example 2 indicated by the one-dot chain line in FIG. 10 is a case where the correction coefficient α is relatively small, and the gradient of the target rotational speed NINT is also relatively small, and the acceleration feeling of high acceleration is higher than that of Comparative Example 1. Although it is inferior, the target rotational speed NINT can be continuously accelerated to a high vehicle speed without reaching the upper limit value NINTmax, and an acceleration feeling with smooth extension can be obtained. For this reason, although a sufficiently satisfactory acceleration performance cannot always be obtained by short-time acceleration in urban areas or the like, excellent acceleration feeling can be obtained by long-time acceleration on an expressway or the like.

  In this way, the acceleration feeling varies depending on the correction coefficient α, so that an excellent acceleration feeling that meets the driver's requirements can be obtained both for short-term acceleration in urban areas and long-term acceleration on highways. It is difficult. On the other hand, in the present embodiment, by reducing the correction coefficient α at a predetermined switching timing, the target rotational speed NINT relative to the vehicle speed V is reached before the target rotational speed NINT reaches the upper limit value NINTmax as shown by the solid line in FIG. The rate of increase of the motor, that is, the rate of increase of the input shaft rotation speed NIN is reduced, and an excellent acceleration feeling that meets the driver's requirements can be obtained even for short-time acceleration such as city driving or long-time acceleration such as highways. ing. That is, as shown in FIG. 3, the linear shift means 110 functionally includes a switching timing determination means 112 and an increase rate switching means 114, and performs signal processing according to the flowchart shown in FIG. . Step R2 in the flowchart of FIG. 9 corresponds to the switching timing determination unit 112, and step R3 corresponds to the increase rate switching unit 114.

  In step R1 of FIG. 9, whether or not the acceleration shift mode is being executed is determined by, for example, a flag indicating the determination result of step S2, and if the acceleration shift mode is being executed, step R2 is executed. In step R2, it is determined whether or not a change condition for switching the correction coefficient α in the present embodiment is satisfied with the linear shift gradient, that is, the gradient (increase rate) of the target rotational speed NINT in FIG. This change condition is for determining whether or not the current acceleration request is for a long time acceleration on an expressway or the like. Specifically, whether or not the elapsed time of the shift control in the acceleration shift mode has become a predetermined value or more. In addition, it is determined whether or not the increase width of the vehicle speed V is equal to or greater than a predetermined value, and whether the increase width of the input shaft rotational speed NIN is equal to or greater than a predetermined value. Since it is considered that the request time is long and acceleration is required for a long time, it is determined that the change condition is satisfied. Further, when the difference in rotational speed from the target rotational speed NINT to the upper limit value NINTmax is less than or equal to a predetermined value, the acceleration feeling is impaired when the target rotational speed NINT changes and reaches the upper limit value NINTmax. When the accelerator operation amount PAP of the user decreases, it is considered that the demand for high acceleration is low and the acceleration with smooth extension is demanded. Therefore, in these cases, it is determined that the change condition is satisfied. It has come to be done. For example, a predetermined value is determined in advance for each of the above determinations, but a different value may be set depending on conditions based on a map or the like that is determined in advance by using the driving state, the driving environment, or the like as a parameter.

  If the determination in step R2 is YES (positive), step R3 is executed to reduce the linear shift gradient. Specifically, it corresponds to the increasing rate of the target rotational speed NINT so that the target rotational speed NINT can be continuously accelerated to a high vehicle speed without reaching the upper limit value NINTmax and an acceleration feeling with a smooth extension can be obtained. The correction coefficient α is reduced. As the correction coefficient α at this time, a constant value may be determined in advance. However, the vehicle speed V, the input shaft rotational speed NIN, or the rotational speed difference between the input shaft rotational speed NIN and the upper limit value NINTmax is used as a parameter. The target rotational speed NINT (or input shaft rotational speed NIN) may be set by a map, an arithmetic expression, or the like so that it can be accelerated to a predetermined high vehicle speed (for example, 100 km / h) without reaching the upper limit value NINTmax. . Further, different correction coefficients α may be determined according to a plurality of changing conditions in step R2. Then, by using this new correction coefficient α, the vehicle speed change correction value NINTLSPD is obtained according to the equation (2), so that the increase rate of the target rotational speed NINT with respect to the vehicle speed V is reduced. The graph shown by the solid line in FIG. 10 is that of this embodiment, and the point C corresponds to the switching timing at which the correction coefficient α is switched in step R3. Note that the correction coefficient α before being reduced in step R3 is set to a relatively large value so that excellent acceleration performance can be obtained, and the target rotational speed NINT is as indicated by points B to C in FIG. Can be increased at a relatively large rate.

  As described above, in the speed change control device according to the present embodiment, the target speed is changed in the acceleration speed change mode in which the speed change control is performed so that the target speed NINT (corresponding to the input shaft speed NIN) increases as the vehicle speed V increases. When the predetermined switching timing (point C in FIG. 10) before the speed NINT reaches the predetermined upper limit value NINTmax is reached, the correction coefficient α of the vehicle speed change correction value NINTLSPD is reduced, so that the target rotational speed NINT is reduced. The rate of increase with respect to the increase in the vehicle speed V is reduced without decreasing it. For this reason, if the correction coefficient α is set to a relatively large value so that the increase rate of the target rotational speed NINT before reaching the switching timing is relatively large, excellent acceleration performance with high acceleration can be obtained. An excellent acceleration feeling of high acceleration that meets the driver's request can be obtained in short-time acceleration such as traveling, while the increase rate of the target rotational speed NINT is reduced when the switching timing is reached, so that the target rotational speed NINT Can be smoothly accelerated while continuously shifting to a high vehicle speed without reaching the upper limit value NINTmax, and a smooth and extended acceleration feeling that meets the requirements of the driver in long-time acceleration such as on a highway It will be obtained.

  Further, in this embodiment, the elapsed time of the shift control in the acceleration shift mode, the increase width of the vehicle speed V, the increase width of the input shaft rotation speed NIN, the rotation speed difference from the input shaft rotation speed NIN to the upper limit value NINTmax, and the driver A change condition is determined for the change in the accelerator operation amount PAP, and if any one of them is satisfied, the correction coefficient α is changed based on the determination of the switching timing. Thus, it is possible to obtain an acceleration feeling that more closely matches the driver's requirements, including whether the vehicle is accelerated for a long time. In other words, when the elapsed time of the shift control in the acceleration shift mode becomes a predetermined value or more, when the vehicle speed V increases by a predetermined value or more, or when the input shaft rotational speed NIN increases by a predetermined value or more. In this case, since the acceleration request time is long and it is considered that the acceleration is required for a long time, the increase rate of the target rotational speed NINT is reduced, so that there is a smooth extension that meets the driver's request. Acceleration feeling can be obtained. In addition, when the rotational speed difference from the input shaft rotational speed NIN to the upper limit value NINTmax is less than or equal to a predetermined value, the acceleration performance is impaired when the input shaft rotational speed NIN changes and reaches the upper limit value NINTmax. By reducing the increase rate of the target rotational speed NINT, a good acceleration feeling can be maintained. In addition, when the driver's accelerator operation amount PAP is reduced, it is considered that acceleration with smooth extension is required because the degree of demand for high acceleration is low, so the rate of increase in the target rotational speed NINT is reduced. Thus, an acceleration feeling that meets the driver's requirements can be obtained.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention is implemented in the aspect which added various change and improvement based on the knowledge of those skilled in the art. Can do.

1 is a skeleton diagram illustrating an example of a vehicle drive device to which the present invention is preferably applied. It is a block diagram explaining the control system of the continuously variable transmission in the vehicle drive device of FIG. It is a block diagram explaining the function with which the electronic control apparatus of FIG. 2 is provided regarding transmission control. FIG. 4 is a diagram showing an example of a shift map used when obtaining a target rotational speed NINT in shift control in the normal shift mode executed by the normal shift means of FIG. 3. FIG. 4 is a flowchart for specifically explaining signal processing executed by a shift mode switching unit in FIG. 3. FIG. It is a figure explaining an example of the map used when setting the acceleration request determination value PAPL in step S1 of FIG. FIG. 4 is a diagram for explaining an example of a map used when a target rotational speed reference value NINTLB is obtained in the shift control in the acceleration shift mode executed by the linear shift means of FIG. 3. It is a figure explaining an example of the map used when calculating | requiring the accelerator depression correction value NINTLPAP in the shift control in the acceleration shift mode performed by the linear shift means of FIG. FIG. 4 is a flowchart for explaining the operation when the increase rate of the target rotational speed is switched at a predetermined switching timing by the switching timing determination unit and the increase rate switching unit of FIG. 3. It is a figure explaining the present Example by which the increase rate of a target rotational speed is switched according to the flowchart of FIG. 9, and a comparative example with a fixed increase rate.

Explanation of symbols

  18: Belt type continuously variable transmission (continuously variable transmission) 36: Input shaft 80: Electronic control device 110: Linear shift means (acceleration shift mode) 112: Switching timing determination means 114: Increase rate switching means PAP: Accelerator operation amount (Acceleration request) NIN: Input shaft rotational speed NINT: Target rotational speed (input shaft rotational speed) NINTmax: Upper limit value V: Vehicle speed C: Predetermined switching timing

Claims (2)

In a transmission control device for a continuously variable transmission for a vehicle having an acceleration shift mode for performing a shift control so that an input shaft rotation speed increases in response to an increase in vehicle speed when a driver demands high acceleration,
Reducing the increase rate of the input shaft rotational speed with respect to the increase in the vehicle speed without decreasing the input shaft rotational speed at a predetermined switching timing before the input shaft rotational speed reaches a predetermined upper limit value. A shift control device for a continuously variable transmission for vehicles. In the acceleration shift mode, shift control is performed using a vehicle speed change correction value that defines an increase rate of the input shaft rotation speed with respect to an increase in the vehicle speed,
An increasing rate switching means for switching the vehicle speed change correction value so that the increasing rate of the input shaft rotation speed with respect to the increase in the vehicle speed is reduced;
Elapsed time of speed change control in the acceleration speed change mode, increase width of the vehicle speed, increase width of the input shaft rotation speed, difference in rotation speed from the input shaft rotation speed to the upper limit value, and change in driver's accelerator operation amount Switching timing determination means for determining the switching timing using at least one of
The shift control device for a continuously variable transmission for a vehicle according to claim 1, comprising:

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