JP2012225449A - Control device for continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a continuously variable transmission which enables travel under an engine load close to an operation point where a net fuel consumption rate is minimized even in an operation state where an accelerator pedal is depressed to accelerate and a change gear ratio is increased, thus preventing the fuel consumption rate from increasing.SOLUTION: The control device includes: a block 80a for setting a target change gear ratio NCST of the continuously variable transmission based on vehicle speed V and an accelerator opening AP; a block 80b for calculating target change speed dNCMD therefor by similar parameters and the like; a block 80c for calculating a change rate dNCST of the target change gear ratio; a block 80d for calculating a correction value KdNCMD of the target change speed based on the change rate when the target change gear ratio NCST is increasing; and a block 80e for deciding a final value NCMD of the target change gear ratio based on the target change gear ratio NCST, the target change speed dNCMD, and the correction value KdNCMD of the target change speed, and for controlling operation of the continuously variable transmission so that the final value will be reached.

Description

  The present invention relates to a control device for a continuously variable transmission.

  An example of a control device for a continuously variable transmission that continuously changes the output of an engine mounted on a vehicle and transmits the output to drive wheels is described in Patent Document 1. In this technology, the target speed change ratio and the target speed change of the target speed change ratio are obtained based on the vehicle speed and the accelerator opening, and the actual speed change ratio is continuously changed to the calculated target speed change ratio at the target change speed. Controls the operation of the transmission.

JP 2000-18347 A

  When the target gear ratio is obtained based on the accelerator opening (and the vehicle speed) as in the technique described in Patent Document 1, the target engine speed corresponding to the accelerator opening is usually the net fuel consumption rate (Brake Specific) in a steady state. The fuel consumption is set to the minimum.

  In that case, in an operating state where the accelerator is depressed and accelerated, the actual engine speed tends to be lower than the target engine speed at the time of steady state, which increases the fuel consumption rate by increasing the engine load. End up.

  Therefore, the object of the present invention is to solve the above-mentioned inconvenience and to run at an engine load close to an operating point at which the net fuel consumption rate is minimized even in an operating state in which the speed ratio is increased by depressing the accelerator. It is an object of the present invention to provide a control device for a continuously variable transmission that prevents an increase in fuel consumption rate.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a control device for a continuously variable transmission that continuously changes the output of an engine mounted on a vehicle and transmits the output to driving wheels. Target speed ratio setting means for setting the target speed ratio NCST of the continuously variable transmission at predetermined time intervals based on the speed and the accelerator opening, and the target change speed dNCMD of the set target speed ratio, A target speed ratio change speed calculating means for calculating based on a deviation of the ratio NCST from the last value NCMD of the previous target speed ratio, the travel speed and the accelerator opening, and the previously set target speed ratio A target speed ratio change rate calculating means for calculating a rate of change dNCST with respect to the target speed ratio, and the calculated change when the set target speed ratio is increased with respect to the previously set target speed ratio. The target change speed correction value calculating means for calculating the target change speed correction value KdNCMD based on the above, the set target speed ratio NCST, the calculated target change speed dNCMD, and the target change speed correction value KdNCMD. Based on this, a final value NCMD of the target speed ratio is determined, and a speed ratio control means for controlling the operation of the continuously variable transmission so as to be the final value of the determined target speed ratio is provided.

  In the continuously variable transmission control device according to claim 2, the target transmission gear ratio setting means sets the target transmission gear ratio NCST by the rotational speed NDR of the input shaft of the continuously variable transmission, and the target transmission gear ratio. The change speed calculation means is configured to calculate the target change speed dNCMD of the target gear ratio with the change speed of the rotational speed NDR of the input shaft of the continuously variable transmission.

  In the control device for a continuously variable transmission according to claim 3, the target gear ratio setting means is configured to set a target gear ratio of the continuously variable transmission based on a characteristic of the engine speed NE with respect to a net fuel consumption rate of the engine. The ratio NCST is set.

  In the continuously variable transmission control device according to claim 1, the target transmission ratio NCST of the continuously variable transmission is set based on the traveling speed of the vehicle and the accelerator opening, and the target change speed is set to the previous change speed. Calculated based on deviation from the final value of the target gear ratio, travel speed, and accelerator opening, calculates a change rate dNCST with respect to the previous value of the set target gear ratio, and the target gear ratio increases with respect to the previous value. The target change speed correction value KdNCMD is calculated based on the calculated change rate, and based on the set target gear ratio NCST, the calculated target change speed dNCMD, and the target change speed correction value KdNCMD. Since the final value NCMD of the target gear ratio is determined and the operation of the continuously variable transmission is controlled so as to be the final value of the determined target gear ratio, the accelerator is depressed to accelerate. In a driving condition where the gear ratio is increased, a correction value for the target change speed is calculated based on the calculated change rate. For example, the correction value is calculated so that the change speed of the target gear ratio increases as the change rate increases. By doing so, it is possible to travel at an engine load close to the operating point at which the net fuel consumption rate is minimized, and thus it is possible to prevent an increase in the fuel consumption rate. In addition, the gear ratio that accelerates by depressing the accelerator, in other words, only when the target gear ratio increases in the driving state where the required driving force is increased, affects the slow acceleration operation state and the deceleration operation state. There is nothing.

  In the continuously variable transmission control apparatus according to the second aspect, the target transmission gear ratio NCST is set by the rotational speed NDR of the input shaft of the continuously variable transmission, and the target change speed dNCMD of the target transmission gear ratio is also set to the same value. Since the calculation is made based on the change speed of the rotational speed NDR of the input shaft of the step transmission, the engine rotational speed can be adjusted by setting the rotational speed of the input shaft of the continuously variable transmission as a target value in addition to the above effect. Can be simplified, and the configuration can be simplified.

  The control device for the continuously variable transmission according to claim 3 is configured to set the target speed ratio NCST of the continuously variable transmission based on the characteristic of the engine speed NE with respect to the net fuel consumption rate of the engine. It is possible to travel at an engine load that is closer to the operating point at which the net fuel consumption rate is minimized, and thus it is possible to better prevent an increase in the fuel consumption rate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an overall control device for a continuously variable transmission according to an embodiment of the present invention. FIG. 2 is a block diagram functionally showing the operation (processing) of the control device for the continuously variable transmission shown in FIG. 1. 3 is a flowchart partially showing the operation of the block diagram shown in FIG. 2. 3 is an explanatory diagram showing the characteristics of the correction value used in the processing of the flow chart. FIG. 3 is an explanatory diagram showing an effect of the processing in the block diagram of FIG. 2.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment for carrying out a continuously variable transmission control device according to the invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing the overall control device of a continuously variable transmission according to an embodiment of the present invention.

  In FIG. 1, the code | symbol 10 shows an engine (internal combustion engine). The engine 10 is mounted on a vehicle 14 having drive wheels 12 and the like.

  A throttle valve (not shown) arranged in the intake system of the engine 10 is mechanically disconnected from an accelerator pedal (not shown) arranged in the vehicle driver's seat, and is a DBW (actuator) such as an electric motor. Drive By Wire) mechanism 16 is connected and driven by DBW mechanism 16.

  The intake air metered by the throttle valve flows through an intake manifold (not shown) and mixes with fuel injected from an injector (fuel injection valve) 20 near the intake port of each cylinder to form an air-fuel mixture, When an intake valve (not shown) is opened, it flows into a combustion chamber (not shown) of the cylinder. In the combustion chamber, the air-fuel mixture is ignited and combusted, and after driving a piston (not shown) to rotate the crankshaft 22, exhaust gas is discharged outside the engine 10.

  The rotation of the crankshaft 22 of the engine 10 is input to a continuously variable transmission (hereinafter referred to as “CVT”) 26 via a torque converter 24. That is, the crankshaft 22 is connected to the pump / impeller 24a via the drive plate of the torque converter 24, while the turbine runner 24b disposed opposite thereto and receiving fluid (hydraulic fluid) is a main shaft (input shaft) MS. Connected to.

  The CVT 26 includes a drive pulley 26a disposed on the main shaft MS, a driven pulley 26b disposed on a counter shaft (output shaft) CS parallel to the main shaft MS, and a metal belt 26c wound around the drive pulley 26a.

  The drive pulley 26a is relatively rotatable with respect to the main shaft MS and is disposed so as not to move in the axial direction. The drive pulley 26a is relatively unrotatable with respect to the main shaft MS and is relatively movable in the axial direction with respect to the fixed pulley half 26a1. The movable pulley half 26a2 is provided with a hydraulic cylinder chamber (not shown).

  The driven pulley 26b is fixed to the countershaft CS so as not to rotate relative to the countershaft CS and cannot move in the axial direction. The driven pulley 26b cannot move relative to the countershaft CS and can move relative to the fixed pulley half 26b1 in the axial direction. The movable pulley half 26b2 is provided with a hydraulic cylinder chamber (not shown).

  In this manner, the CVT 26 is connected to the drive pulley 12a that is movable in the axial direction when hydraulic fluid is supplied to the hydraulic cylinder chamber of the movable pulley half 26a2, and the drive wheel 12, and the movable pulley half 26b2. A driven pulley 26b that is movable in the axial direction when hydraulic oil is supplied to the hydraulic cylinder chamber, and a belt 26c that is wound around the drive pulley 26a and the driven pulley 26b are provided.

  The belt 26c is composed of a large number of elements having a V surface and two bundles of rings that support the element, and the V surface of the element is pressed against the pulley surfaces of the drive pulley 26a and the driven pulley 26b on both sides. Thus, the driving force (torque) of the engine 10 is transmitted from the drive pulley 26a to the driven pulley 26b.

  The CVT 26 is connected to the forward / reverse switching device 30. The forward / reverse switching device 30 includes a forward clutch 30a, a reverse brake clutch 30b, and a planetary gear mechanism 30c disposed therebetween. The CVT 26 is connected to the engine 10 via the forward clutch 30a.

  In the planetary gear mechanism 30c, the sun gear 30c1 is fixed to the main shaft MS, and the ring gear 30c2 is fixed to the fixed pulley half 26a1 of the drive pulley 26a via the forward clutch 30a.

  A pinion 30c3 is disposed between the sun gear 30c1 and the ring gear 30c2. Pinion 30c3 is coupled to sun gear 30c1 by carrier 30c4. When the reverse brake clutch 30b is operated, the carrier 30c4 is fixed (locked) thereby.

  The rotation of the counter shaft CS is transmitted to the secondary shaft (intermediate shaft) SS via the reduction gears 32 and 34, and the rotation of the secondary shaft SS is transmitted to the left and right drive wheels (only one side is shown) 12 via the gear 36 and the differential D. To be told.

  Switching between the forward clutch 30a and the reverse brake clutch 30b is performed by the driver operating a shift lever 40 provided at a vehicle driver's seat, for example, having positions P, R, N, D, S, and L. When any position of the shift lever 40 is selected by the driver, the selection operation is transmitted to the manual valve of the hydraulic pressure supply mechanism 42 such as the CVT 26.

  For example, when the D, S, and L positions are selected, the spool of the manual valve moves accordingly, and hydraulic oil (hydraulic pressure) is discharged from the piston chamber of the reverse brake clutch 30b, while the hydraulic oil (hydraulic pressure) is discharged to the piston chamber of the forward clutch 30a. Hydraulic pressure is supplied and the forward clutch 30a is engaged.

  When the forward clutch 30a is engaged, all gears rotate together with the main shaft MS, and the drive pulley 26a is driven in the same direction (forward direction) as the main shaft MS.

  On the other hand, when the R position is selected, hydraulic oil is discharged from the piston chamber of the forward clutch 30a, while hydraulic pressure is supplied to the piston chamber of the reverse brake clutch 30b, and the reverse brake clutch 30b is operated. As a result, the carrier 30c4 is fixed, the ring gear 30c2 is driven in the opposite direction to the sun gear 30c1, and the drive pulley 26a is driven in the opposite direction (reverse direction) to the main shaft MS.

  When the P or N position is selected, hydraulic oil is discharged from both piston chambers, the forward clutch 30a and the reverse brake clutch 30b are both released, and power transmission via the forward / reverse switching device 30 is cut off. The power transmission between the engine 10 and the drive pulley 26a of the CVT 26 is cut off.

  A crank angle sensor 44 is provided at an appropriate position such as near the camshaft (not shown) of the engine 10 and outputs a signal indicating the engine speed NE for each predetermined crank angle position of the piston. In the intake system, an absolute pressure sensor 46 is provided at an appropriate position downstream of the throttle valve, and outputs a signal proportional to the intake pipe absolute pressure (engine load) PBA.

  The actuator of the DBW mechanism 16 is provided with a throttle opening sensor 50, which outputs a signal proportional to the throttle valve opening TH through the amount of rotation of the actuator, and an accelerator opening sensor 54 is provided in the vicinity of the accelerator pedal 52. And outputs a signal proportional to the accelerator pedal opening AP corresponding to the driver's accelerator pedal operation amount.

  The output of the crank angle sensor 44 and the like described above is sent to the engine controller 60. The engine controller 60 includes a microcomputer, determines the target throttle opening based on the sensor outputs, controls the operation of the DBW mechanism 16, and determines the fuel injection amount to drive the injector 20.

  The main shaft MS is provided with an NT sensor (rotational speed sensor) 62, which determines the rotational speed of the turbine runner 24b, specifically the rotational speed of the main shaft MS, more specifically the input shaft rotational speed of the forward clutch 30a. The pulse signal shown is output.

  An NDR sensor (rotational speed sensor) 64 is provided at an appropriate position in the vicinity of the drive pulley 26a of the CVT 26 to output a pulse signal corresponding to the rotational speed NDR of the drive pulley 26a, in other words, the rotational speed of the input shaft of the CVT 26. In addition, an NDN sensor (rotational speed sensor) 66 is provided at an appropriate position in the vicinity of the driven pulley 26b, and outputs a pulse signal corresponding to the rotational speed NDN of the driven pulley 26b, in other words, the rotational speed of the output shaft of the CVT 26. .

  A vehicle speed sensor (rotational speed sensor) 70 is provided in the vicinity of the gear 36 of the secondary shaft SS, and a pulse signal indicating the rotational speed of the output shaft of the CVT 26 or the vehicle speed (traveling speed of the vehicle 14) V through the rotational speed of the gear 36 is provided. Output. A shift lever position sensor 72 is provided in the vicinity of the shift lever 40 described above, and outputs a POS signal corresponding to a position such as R, N, or D selected by the driver.

  An oil temperature sensor 74 is disposed at an appropriate position of the hydraulic pressure supply mechanism 42 and outputs a signal corresponding to the oil temperature (temperature of the hydraulic oil ATF) TATF.

  The output of the NT sensor 62 and the like described above is sent to the shift controller 80 including the outputs of other sensors (not shown). The shift controller 80 also includes a microcomputer and is configured to be able to communicate with the engine controller 60.

  Based on these detected values, the shift controller 80 controls the operations of the forward / reverse switching device 30, the torque converter 24, and the CVT 26 by exciting / de-exciting the electromagnetic solenoid in the hydraulic pressure supply mechanism 42.

  That is, the shift controller 80 supplies hydraulic oil to the torque converter 24, the forward / reverse switching mechanism 30 and the CVT 26 by exciting and demagnetizing a plurality of electromagnetic control valves in the hydraulic supply mechanism 42 according to the position of the manual valve. In this embodiment, the shift controller 80 functions as a control device for the CVT 26.

  2 is a block diagram functionally showing the operation (process) of the shift controller 80, FIG. 3 is a flowchart partially showing the operation of the block diagram shown in FIG. 2, and FIG. 4 is a process of FIG. FIG. 5 is an explanatory diagram showing the effect of the processing of the block diagram of FIG. 2. 2 is executed every predetermined time, for example, 10 msec.

  As shown in the figure, the shift controller 80 is set with a target gear ratio setting block (target gear ratio setting means) 80a for setting the target gear ratio NCST of the CVT 26 every 10 msec based on the vehicle speed V and the accelerator pedal opening AP. A target gear ratio change speed calculation block (target) for calculating the target speed change dNCMD of the target speed ratio based on the deviation of the target speed ratio NCST from the last target speed ratio final value NCMD, the vehicle speed V, and the accelerator pedal opening AP. A transmission ratio change speed calculation means) 80b, a target transmission ratio change rate calculation block (target transmission ratio change rate calculation means) 80c for calculating a change rate dNCST of the set target transmission ratio with respect to the previously set target transmission ratio, When the set target gear ratio is increasing relative to the previously set target gear ratio, the target change speed is based on the calculated rate of change. A target change speed correction value calculation block (target change speed correction value calculation means) 80d for calculating a correction value KdNCMD, a set target speed ratio NCST, a calculated target change speed dNCMD, and a target change speed correction value KdNCMD. Based on this, a final gear ratio NCMD of the target gear ratio is determined, and a gear ratio control block (control means) 80e for controlling the operation of the CVT 26 so as to be the final value of the determined target gear ratio.

  Each will be described below.

  The target gear ratio setting block 80a sets the CVT target gear ratio NCST at a predetermined time, for example, every 10 msec, based on the vehicle speed V and the accelerator pedal opening AP. More specifically, the target gear ratio setting block 80a sets the target gear ratio NCST with the rotational speed of the input shaft of the CVT 26 (the rotational speed of the drive pulley 26a) NDR [rpm].

  The target gear ratio setting block 80a sets the target gear ratio NCST based on the characteristic of the engine speed NE with respect to the net fuel consumption rate BSFC of the engine 10.

  FIG. 5A is an explanatory diagram showing the characteristics of the engine speed NE with respect to the net fuel consumption rate BSFC. The target gear ratio setting block 80a sets the target gear ratio NCST of the CVT 26 based on the characteristics as shown in the figure. .

  The target gear ratio change speed calculation block 80b converts the target change speed dNCMD of the set target speed ratio into a deviation from the final target speed ratio NCMD of the previous target speed ratio NCST, the vehicle speed V, and the accelerator pedal opening AP. Based on the calculation, more specifically, similar to the target gear ratio NCST, the target change speed dNCMD of the target gear ratio is calculated by the rotational speed NDR of the input shaft of the CVT 26.

  The target gear ratio change rate calculation block 80c calculates a change rate dNCMD of the set target gear ratio NCST with respect to the previously set target gear ratio NCST. That is, the target gear ratio change rate calculation block 80c calculates a change rate dNCMD with respect to the target speed ratio NCST set last time (before 10 msec) of the current value of the target speed ratio NCST set every 10 msec.

  The target change speed correction value calculation block 80d calculates a target change speed correction value KdNCMD based on the calculated change rate when the set target speed ratio NCST is increased with respect to the previously set target speed ratio. calculate.

  The gear ratio control block 80e determines the final value NCMD of the target gear ratio based on the set target gear ratio NCST, the calculated target change speed dNCMD, and the target change speed correction value KdNCMD.

  The transmission ratio control block 80e includes a multiplier 80e1 and an adder (integrator) 80e2, and a product (corrected target change speed) obtained by multiplying the target change speed dNCMD and the target change speed correction value KdNCMD by the multiplier 80e1. Is added (integrated) by the adder 80e2 and returned to the target gear ratio change speed calculation block 80b, and the final value NCMD of the target speed ratio is determined so that the target speed ratio NCST changes at the corrected target change speed. The operation of the CVT 26 is controlled so that the final value NCMD of the target gear ratio is obtained.

  FIG. 3 is a flowchart showing the processing of the target gear ratio change rate calculation block 80c and the target change speed correction value calculation block 80d.

  Explaining below, the time change rate dNCST of the target speed ratio NCST is calculated in S (step) 10, that is, the target speed ratio set last time (before 10 msec) of the current value of the target speed ratio NCST set every 10 msec. The rate of change dNCST relative to NCST is calculated. The change rate dNCST is calculated by obtaining a difference [rpm / 10 msec] per unit time between the current value and the previous value of the target gear ratio NCST.

  Next, in S12, it is determined whether dNCST is a positive value, that is, whether the currently set target gear ratio NCST is increased with respect to the previously set target gear ratio. To skip.

  On the other hand, if the determination is affirmative, the process proceeds to S14, where a target change speed correction value KdNCMD is calculated based on the calculated change rate (time change rate) dNCST, and more specifically, KdNCMD is calculated from the target speed ratio change speed correction characteristic. calculate.

  FIG. 4 is an explanatory diagram showing the characteristics, and the correction value KdNCMD is calculated by searching the characteristics from the time change rate dNCST.

  Since the correction value KdNCMD is calculated by the multiplication term as described above, the correction value KdNCMD is set to 1.0 (no correction) when the time change rate dNCST is less than or equal to zero, while the positive value exceeding the zero is positive. The value, that is, a value exceeding 1.0 is set only when the target gear ratio NCST is increasing.

  As shown in the figure, the correction value KdNCMD is set so as to increase as the time change rate dNCST increases, and is set so as to be saturated at an appropriate value. In FIG. 4, the symbol a indicates the characteristics when the vehicle speed V is low, and the symbol b indicates the characteristics when the vehicle speed V is high. The correction value between the symbols a and b is calculated by interpolating the correction values of the symbols a and b.

  FIG. 5A is an explanatory diagram showing the characteristics of the engine speed NE with respect to the net fuel consumption rate BSFC, FIG. 5B is a diagram of this embodiment when the processing of this embodiment is not performed, and FIG. 5C is a diagram of this embodiment. 3 is a time chart showing behaviors of an engine speed NE, an accelerator pedal opening AP, and a vehicle speed V when the processing shown in FIG. 2 is performed.

  In an operating state where the gear ratio NCST is increased so as to accelerate by depressing the accelerator, the correction value KdNCMD of the target change speed dNCMD changes as the time change rate increases based on the calculated time change rate (change rate) dNCST. By calculating so as to increase the speed, the rotation speed NDR of the drive pulley 26a detected as shown in the lower part of FIG. 5C well follows the target speed ratio NCST.

  As a result, as shown in the upper part of FIG. 5C, the engine speed NE can be increased early (moved to the right on the vertical axis in FIG. 5A). Such an effect cannot be expected when the processing of this embodiment shown in FIG. 5B is not performed.

  As a result, it is possible to travel at an engine load close to the operating point at which the net fuel consumption rate is minimized, and thus an increase in the fuel consumption rate can be prevented.

  As described above, in this embodiment, the control device (shift controller 80) of the continuously variable transmission (CVT) 26 that continuously changes the output of the engine 10 mounted on the vehicle 14 and transmits it to the drive wheels 12. ), A target gear ratio setting means (block) for setting the target gear ratio NCST of the continuously variable transmission every predetermined time (for example, 10 msec) based on the travel speed (vehicle speed) V of the vehicle and the accelerator pedal opening AP. 80a and the target change speed dNCMD of the set target gear ratio are calculated based on the deviation of the target speed ratio NCST from the last target speed ratio final value NCMD, the travel speed V, and the accelerator pedal opening AP. Target speed ratio change speed calculating means (block) 80b for calculating the change ratio dNCST of the set target speed ratio NCST with respect to the previously set target speed ratio Target speed ratio change rate calculating means (block) 80c (S10), and when the set target speed ratio NCST is increased with respect to the previously set target speed ratio, based on the calculated change rate. Target change speed correction value calculating means (block) 80d (S12, S14) for calculating the target change speed correction value KdNCMD, the set target speed ratio NCST, the calculated target change speed dNCMD and the target change. A speed ratio control means (block) for determining the final value NCMD of the target speed ratio based on the speed correction value KdNCMD and controlling the operation of the continuously variable transmission so as to be the final value of the determined target speed ratio. ) 80e, the calculated change rate (time variation) in the driving state where the gear ratio is increased so as to accelerate by depressing the accelerator. Rate) Based on dNCST, a target change speed correction value KdNCMD is calculated. Specifically, the net fuel consumption rate is calculated by calculating the correction value so that the change speed of the target gear ratio increases as the change rate increases. It is possible to travel with an engine load close to the minimum operating point, and thus it is possible to prevent an increase in fuel consumption rate. In addition, the gear ratio that accelerates by depressing the accelerator, in other words, only when the target gear ratio increases in the driving state where the required driving force is increased, affects the slow acceleration operation state and the deceleration operation state. There is nothing.

  The target speed ratio setting means 80a sets the target speed ratio by the rotational speed (NDR) of the input shaft of the continuously variable transmission, and the target speed ratio change speed calculating means 80b is a target change of the target speed ratio. Since the speed dNCMD is calculated by changing the speed NDR of the input shaft of the continuously variable transmission, in addition to the above-described effect, the engine speed can be increased by setting the speed NDR of the input shaft of the CVT 26 as a target value. Adjustment of the number NE is facilitated, and the configuration can be simplified.

  Further, since the target gear ratio setting means 80a is configured to set the target gear ratio NCST of the continuously variable transmission based on the characteristic of the engine speed NE with respect to the net fuel consumption rate of the engine 10, the net fuel consumption It is possible to drive at an engine load that is closer to the operating point at which the rate (Brake Specific Fuel Consumption) is minimized, and thus it is possible to better prevent an increase in the fuel consumption rate.

  In the above description, the belt type is disclosed as the CVT (continuously variable transmission). However, the belt type is not limited thereto, and may be a chain type or a toroidal type.

  DESCRIPTION OF SYMBOLS 10 Engine (internal combustion engine), 12 Drive wheel, 14 Vehicle, 16 DBW mechanism, 24 Torque converter, 26 Continuously variable transmission (CVT), 26a Drive pulley, 26a2 Movable pulley half, 26b Driven pulley, 26b2 Movable pulley half , 30 Forward / reverse switching device, 42 Hydraulic supply mechanism, 54 Vehicle speed sensor, 60 Engine controller, 64 NDR sensor, 70 Vehicle speed sensor, 80 Shift controller, 80a Target gear ratio setting block (means), 80b Target gear ratio change speed calculation block (Means), 80c Target gear ratio change rate calculation block (Means), 80d Target change speed correction value calculation block (Means), 80e Gear ratio control block (Means), MS main shaft, CS counter shaft, SS secondary shaft

Claims (3)

  A control device for a continuously variable transmission that continuously changes the output of an engine mounted on a vehicle and transmits the output to a drive wheel, based on a travel speed of the vehicle and an accelerator opening, a target shift of the continuously variable transmission A target speed ratio setting means for setting the ratio NCST every predetermined time; a target change speed dNCMD of the set target speed ratio; and a deviation of the target speed ratio NCST from a last target speed ratio final value NCMD Target speed ratio change speed calculating means for calculating based on the travel speed and the accelerator opening, and target speed ratio change rate calculating means for calculating a change rate dNCST of the set target speed ratio with respect to the previously set target speed ratio. And the target change speed correction value KdNCMD based on the calculated change rate when the set target speed ratio is increased with respect to the previously set target speed ratio. Based on the target change speed correction value calculation means to be calculated, the set target speed change ratio NCST, the calculated target change speed dNCMD and the target change speed correction value KdNCMD, the final value NCMD of the target speed change ratio is determined. And a gear ratio control means for controlling the operation of the continuously variable transmission so as to be the final value of the determined target gear ratio.   The target speed ratio setting means sets the target speed ratio NCST by the rotational speed NDR of the input shaft of the continuously variable transmission, and the target speed ratio change speed calculation means sets the target speed change ratio dNCMD of the target speed ratio. The control device for a continuously variable transmission according to claim 1, wherein the controller is calculated based on the changing speed of the rotational speed NDR of the input shaft of the step transmission.   The target speed ratio setting means sets the target speed ratio NCST of the continuously variable transmission based on the characteristic of the engine speed NE with respect to the net fuel consumption rate of the engine. Control device for continuously variable transmission.

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