JP2901609B2 - Transmission control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a shift control device for controlling a shift speed based on a speed ratio or a rotational speed in a belt-type continuously variable transmission for a vehicle, and more particularly, to a control for correcting a target speed ratio during an upshift or a downshift. .

[Prior art]

In this type of continuously variable transmission, it is conceivable to perform speed change control so as to perform convergence satisfactorily so as not to cause overshoot, hunting, and the like, in addition to followability in a transient state. For this reason, for example, it has been proposed that the shift amount is controlled by obtaining the operation amount at the shift speed by using a difference between the target value of the target speed ratio and the actually measured value of the actual speed ratio, a factor taking convergence into account, and the like. There is a tendency that the target value and the operation amount are further corrected and optimized according to various special running conditions, the state of the engine or the drive system, and the like. Therefore, there is a prior art in Japanese Patent Application Laid-Open No. 59-183162, for example, related to the shift control of the continuously variable transmission. Here, the optimum fuel efficiency target rotation speed of the engine is determined based on the load amount required for the engine and the speed of the vehicle. For this purpose, speed ratio adjusting means for changing the speed ratio of the continuously variable transmission is provided.

[Problems to be solved by the invention]

However, in the event of a heavy load such as when the air conditioner is operating, if control is performed to set the gear position to low gear, that is, set the target value to the downshift side in order to increase the driving force, a shock due to the downshift occurs. In addition, the driving force of the air conditioner is reduced, and the drivability is deteriorated. Conversely, if the load is greatly reduced, for example, when the air conditioner is stopped, the upshift may cause a sudden increase in the number of vehicles that the driver does not expect. The present invention has been made based on the above circumstances, and is suitable for a downshift or an upshift when a control condition for changing a target value of a gear ratio is given, such as when an air conditioner is operated or stopped. It is an object of the present invention to provide a shift control device for a continuously variable transmission that can take a long time to avoid occurrence of a shock, a sudden increase in vehicle speed, and the like, and maintain excellent drivability.

[Means for Solving the Problems]

For this reason, the present invention is a shift control system of a continuously variable transmission, wherein the control device determines a shift operation amount from elements of the searched target speed ratio and actual speed ratio to perform shift control. Detecting means for detecting ON and OFF signals of the air conditioner control; and correcting means for correcting the target value of the target gear ratio based on the signal from the detecting means. After the input, the target value change amount is gradually corrected over a predetermined time or at a predetermined speed so that the shift speed in the upshift and the downshift becomes small.

[Action]

Therefore, when changing the target value, it is possible to avoid occurrence of a shock at the time of a downshift and to avoid a sharp increase in the vehicle speed at the time of an upshift, thereby maintaining excellent drivability.

【Example】

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, the overall configuration of a drive system in which a belt-type continuously variable transmission is combined with an electromagnetic clutch will be described. The engine 1 is connected to a continuously variable transmission 4 via an electromagnetic clutch 2 such as an electromagnetic powder type and a forward / reverse switching device 3, and is connected to the continuously variable transmission 4 from the continuously variable transmission 4.
The transmission gears are configured to be transmitted to drive wheels 9 via a set of reduction gears 5, output shafts 6, differential gears 7, and axles 8. The electromagnetic powder type clutch 2 has a drive member 2a on an engine crankshaft 10 and a driven member 2b having a clutch coil 2c on an input shaft 11. And clutch coil 2c
The electromagnetic powder is coupled and accumulated in the gap between the two members 2a and 2b in a chain by the clutch current flowing through the clutch, and the clutch engagement / disengagement and clutch torque are variably controlled by the coupling force. The forward / reverse switching device 3 is synchronously meshed with a gear, a hub, and a sleeve between the input shaft 11 and the transmission main shaft 12, and includes a forward position at which the input shaft 11 is directly connected to the main shaft 12, and an input shaft. And a retracted position for transmitting the rotation of the rotation 11 to the main shaft 12 in the reverse direction. The continuously variable transmission 4 includes a main shaft 12 and a sub shaft arranged in parallel with the main shaft 12.
The primary shaft 12 is provided with a primary pulley 14 having a hydraulic cylinder 14a having a hydraulic cylinder 14a and the secondary shaft 13 is similarly provided with a secondary pulley 15 having a hydraulic cylinder 15a. A drive belt 16 is wound around both pulleys 14 and 15, and both cylinders 14a and 15a are configured as a hydraulic control circuit 17. Then, a line pressure according to the transmission torque is supplied to both cylinders 14a and 15a to apply a pulley pressing force, and the primary pressure changes the ratio of the winding diameter of the drive belt 16 to the pulleys 14 and 15 to continuously change the speed. It is configured to control. Next, an electronic control system of the electromagnetic powder type clutch 2 and the continuously variable transmission 4 will be described. Engine speed sensor 19 for engine 1 and primary pulley speed sensor 2 for continuously variable transmission 4
1, a secondary pulley rotation speed sensor 22, and sensors 23 and 24 for detecting the operation status of the air conditioner and the choke. Also,
The shift lever 25 of the operation system is mechanically connected to the forward / reverse switching device 3, and has a shift position sensor 26 for detecting each of the reverse (R), drive (D), and sporty drive (Ds). Further, the accelerator pedal 27 has an accelerator switch 28 for detecting an accelerator depression state, and a throttle opening sensor 29 on the throttle valve side. The various signals of the switches and the sensors are input to the electronic control unit 20 and processed by software using a microcomputer or the like. The clutch control signals of the start, lag, and direct connection modes output from the electronic control unit 20 are input to the electromagnetic clutch 2, and the shift control signal and the line pressure control signal are input to the hydraulic control circuit 17 of the continuously variable transmission 4. The operation is performed. 2, the electromagnetic clutch control system and the continuously variable transmission control system of the control unit 20 will be described. First, the electromagnetic clutch control system includes a reverse excitation mode determination unit 32 to which signals of the engine speed Ne and the neutral (N) and parking (P) ranges other than R, D, and Ds of the shift position sensor 26 are input. For example, in the case of Ne <300 rpm or in the case of the P and N ranges, the reverse excitation mode is determined, and the output determining unit 33 allows a small current in a direction opposite to the normal direction to flow. Then, the electromagnetic clutch 2 is completely released except for the residual magnetism. In addition, there is provided an energization mode determination unit 34 to which a determination output signal of the reverse excitation mode half bottom 32, a depression signal of the accelerator switch 28, and a rotation (hereinafter referred to as vehicle speed V) signal of the secondary pulley rotation speed sensor 22 are input. And the like, and the discrimination signal is input to the start mode current setting unit 35, the drag mode current setting unit 36, and the direct connection mode current setting unit 37. The start mode current setting unit 35 sets the start characteristics individually in relation to the engine speed Ne and the like in the case of normal start or start using the air conditioner and choke. Then, the starting characteristics are corrected based on the travel ranges of the throttle opening θ and the vehicle speeds V, R, D, and Ds, and the clutch current is set. The drag mode current setting unit 36 determines a small drag current when the accelerator is released at a low vehicle speed in each range of R, D, and Ds,
A drag torque is generated in the electromagnetic clutch 2 to reduce the play of the belt and the drive system, thereby smoothly starting the vehicle. In this mode, the current is determined to be zero current until just before the vehicle stops after the clutch in the D range is released, thereby ensuring the coasting. The direct-coupling mode current setting unit 37 determines the direct-coupling current based on the relationship between the vehicle speed V and the throttle opening θ in each of the ranges of R, D, and Ds, fully engages the electromagnetic clutch 2, and saves power in the engaged state. . The output signals of these current setting units 35, 36, and 37 are input to the output determination unit 33, and the clutch current is determined according to the instruction. Next, regarding the speed change control system of the stepless speed change control, the primary pulley speed Np and the primary pulley speed Ns of the primary pulley speed sensor 21 and the secondary pulley speed sensor 22 are input to the actual speed ratio calculating unit 40, The actual speed ratio i is calculated from the actual speed ratio i = Nb / Ns. The actual gear ratio i and the throttle opening θ of the throttle opening sensor 29
Is input to the target primary pulley rotation speed search unit 41, and R, D,
A target primary pulley rotation speed NPD is searched for each range of Ds using a map of i-θ based on a shift pattern.
The target primary pulley rotation speed NPD is calculated by NPD correction means.
At 60, corrections are made as described below. That is, when the NPD correction means 60 receives a signal “OFF → ON” or “ON → OFF” at the time of switching between operation and non-operation from the air conditioner operation sensor 23 as shown in FIG. NPD A / C uniquely determined by the ratio i is added to the target primary pulley rotation speed NPD to compensate for the decrease in driving force, or is reduced from the target primary pulley rotation speed NPD to remove excess driving force. Perform control. In this case, the above N
The PD correction means 60 adds or subtracts, for each cycle, an amount obtained by dividing NPDA / C by, for example, Δt = 256 (the number of timing clocks). Correction is made so as to reach the primary pulley rotation speed NPD. Instead of setting the time Δt, an increment (change rate) of NPD A / C per time unit may be determined so as to converge to the new target primary pulley rotation number NPD. In addition, air conditioner operation sensor 23
When is in the "ON" state or the "OFF" state, no correction control is performed. Then, the target primary pulley rotation speed NPD and the secondary rotation speed Ns that have passed through the NPD correction means 60 are input to the target speed ratio calculation unit 42, and the target speed ratio is is = NPD / N
It is calculated by s. Further, the coefficients K ₁ and K ₂ of the target gear ratio is good coefficient setting section 44 are set to
The target speed ratio change speed dis / dt is calculated based on the change amount of the target speed ratio is over a certain period of time. Then, the actual speed ratio i, the target speed ratio is, and the target speed ratio change speed dis / dt are input to the speed change calculator 45, and the speed change di / dt is calculated as follows. di / dt = K ₁ (is−i) + K ₂ · dis / dt In the above equation, is−i is a control amount of the target and actual speed ratio deviation, and dis / dt is a delay correction element of the control system. The gear speed di / dt and the actual gear ratio i are the duty ratio search units.
Enter 46. Here, the duty ratio D of the manipulated variable is D
= F (di / dt, i), the duty ratio D becomes di / dt in upshift and downshift.
-Searched using the map of i. The value of the duty ratio D of the manipulated variable is supplied to the hydraulic control circuit
Output to the 17 speed change control solenoid valve 48. Subsequently, a line pressure control system of the continuously variable transmission control will be described. Engine speed sensor 19, throttle opening sensor 29
And an engine torque search unit 50 to which the engine speed Ne and the throttle opening θ are inputted, and obtains the engine torque T from the torque characteristic map of θ-Ne. This engine torque T
The signal of the actual gear ratio i of the actual gear ratio calculator 40 is input to the target line pressure setting unit 51, and the target line pressure P Ld is determined by the required line pressure according to the engine torque and the value of the actual gear ratio i. On the other hand, since the maximum value of the line pressure fluctuates as the pump discharge pressure changes depending on the engine speed, the maximum line pressure search unit 52 for inputting the engine speed Ne and the actual speed ratio i to detect this fluctuation state. And the maximum line pressure P Lmax is obtained from the Ne-i map. The target line pressure P Ld and the maximum line pressure P Lmax are input to the pressure reduction value calculation unit 53, and the line pressure P Ld is calculated as a ratio of the target line pressure P Ld to the maximum line pressure P Lmax.
LR is calculated, and this is input to the duty ratio search unit 54 to determine the duty ratio D according to the line pressure PLR. The duty signal is output to the line pressure control solenoid valve 56 via the drive unit 55. Next, the operation of the thus configured shift control device for a continuously variable transmission will be described. First, the power corresponding to the depression of the accelerator from the engine 1 is input to the primary pulley 14 of the continuously variable transmission 4 via the electromagnetic clutch 2 and the forward / reverse switching device 3, and the drive belt 16,
The power is shifted by the secondary pulley 15 and is transmitted to the drive wheels 9 to travel. During the running, the target line pressure is set to be larger as the engine torque T is larger in the low speed stage where the value of the actual speed ratio i is larger, and a corresponding duty signal is input to the solenoid valve 56 to adjust the control pressure. pressure, by Gosuru line pressure in the averaged pressure, to increase the line pressure P _L. Then, as the shift to the high-speed gear stage is performed, the gear ratio i becomes smaller, and the engine torque T becomes smaller, so that the line pressure P _L is controlled to decrease. Pulley pressing force corresponding to the transmission torque of the pulley. The line pressure P _L is always supplied to the secondary cylinder 15a, and the shift speed is controlled by supplying and discharging oil to and from the primary cylinder 14a by a shift speed control valve (not shown) by the control pressure of the solenoid valve 48. This will be described below. First, the signals Np, Ns, and θ from the primary pulley rotation speed sensor 21, the secondary pulley rotation speed sensor 22, and the throttle opening sensor 29 are read, and the actual gear ratio calculation unit 40 of the control unit 20 obtains the actual gear ratio i. . In addition, the target primary pulley rotation speed search unit 41 temporarily determines the target primary pulley rotation speed based on the actual gear ratio i and the throttle opening θ based on the shift pattern for each of the R, D, and Ds ranges from the shift position sensor 26. NPD is retrieved from the map, and the target gear ratio calculation unit
At 42, a target gear ratio is corresponding to the target primary pulley rotation speed NPD is calculated. Therefore, in the region where the primary speed is constant, the target speed ratio is the same fixed value as calculated by the Ns-θ method, but in the region where the primary speed is variable, the target speed ratio is Is set to be offset toward the lower gear, and the target gear ratio is is a value that changes by itself. Using the actual speed ratio i, the target speed ratio is, the dis / dt of the target speed ratio change speed calculation unit 43, and the coefficients K ₁ and K ₂ of the coefficient setting unit 44, the speed change unit 45 calculates the speed change di / Find dt. Then, the duty ratio search unit 46 searches the duty ratio D based on the shift speed di / dt and the actual speed ratio i. The duty signal is input to a solenoid valve 48 to generate a pulse-like control pressure, whereby the shift speed control valve is repeatedly operated at two positions of oil supply and oil discharge. Here, when the duty ratio becomes small, the operation time at the refueling position becomes longer due to the off time, and the primary cylinder
Refueling at 14a, thus upshifting. On the other hand, when the duty ratio increases, the operating time at the oil discharge position becomes longer due to the on-time, and the primary cylinder 14a is drained, thereby causing a downshift.
Since the shift speed di / dt in this case corresponds to a change in the duty ratio, the target speed ratio is and the actual speed ratio i
Is small, the change in the duty ratio is small and the change in the flow rate of the primary cylinder 14a is small, so that the shift speed is reduced. On the other hand, as the deviation between the target speed ratio is and the actual speed ratio i increases, the change in the duty ratio causes the flow rate change of the primary cylinder 14a to increase, and the speed change speed increases. In this way, in the entire shift range of the low gear and the high gear, the upshift or the downshift is performed while changing the shift speed, and the shift is performed in a stepless manner. Next, the correction control of the target primary pulley rotation speed NPD will be specifically described with reference to FIG. First, in step S101, the NPD A / C is searched from the map prepared in advance by the NPD correction means 60 from the actual gear ratio i detected by the actual gear ratio calculation unit 40. Then, step S1
In 02, the signal from the air conditioner operation sensor 23 is “OFF”
It is determined whether or not "ON". If affirmative, step S103 is performed.
And the flag 1 is set. Next, in step S104, the flag 2 is cleared, and in step S105, the set time Tmold of the timer is substituted for Tm, and the flow shifts to step S106. If the determination in step S102 is negative, the process proceeds to step S107, where the signal from the air conditioner operation sensor 23 is set
→ "OFF" is determined, and if affirmative, step S108
If not, the process moves to step S106. Step S108
Then, the flag 1 is cleared, the flag 2 is set in step S109, and the time Tmold is substituted for Tm in step S110. In step S106, it is determined whether or not the flag 1 is set. If the flag is set, the process proceeds to step S111 and Tm
Substitute + A for Tm. Here, A is an addition amount in one cycle. Next, in step S112, it is determined whether Tm is greater than 255. If it is larger, the flow shifts to step S113 to set NPD '= NPDA / C, and in the next step S114, 255 is substituted for Tm. If T in step S112
If m is smaller or equal, the process proceeds to step S115 and NP
D ′ = NPDA / C × Tm / 256, and in the next step S116, Tmold
Is substituted for Tm. If the flag 1 is clear in step S106, it is determined in step S117 whether the flag 2 is set. If the flag 2 is in the set state, Tm−
Substitute B for Tm. Here, B is a subtraction amount in one cycle. Next, in step S119, it is determined whether or not Tm is greater than 0.
In step S121, Tm is set to 0 in step S121. If Tm is greater than or equal to 9 in step S119, the process proceeds to step S122 to calculate NPD ′ = NPDA / C × Tm / 256, and substitutes Tm for Tmold in step S123. If the flag 2 is clear in step S117, N is determined in step S124.
PD '= 0. In any case, in step S125, NPD 'is added to the initial target primary pulley rotation speed NPD, and this is newly set as the target primary pulley rotation speed NPD. In this way, in the present invention, N Pd A / C is gradually added to N PD over a predetermined time (see FIG. 4).

【The invention's effect】

The present invention has been described in detail above.When the control condition for changing the target value of the gear ratio is given at the time of operating or stopping the air conditioner, it takes a proper time to downshift or upshift, It avoids shocks and sudden increases in vehicle speed, and maintains excellent drivability.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an embodiment of a transmission control device according to the present invention, FIG. 2 is a block diagram of an electric control system, FIG. 3 is a flowchart of an operation, and FIG. FIG. 4 ... continuously variable transmission, 17 ... hydraulic control circuit, 20 ... electronic control unit, 40 ... actual gear ratio calculator, 42 ... target gear ratio calculator, 45 ... gear speed calculator, 46 ... ... Duty ratio search unit, 48... Shift control solenoid valve, 60.

Claims (1)

(57) [Claims] 1. A control device for performing a shift control in a shift control system of a continuously variable transmission by determining a shift operation amount from elements of a searched target speed ratio and an actual speed ratio. Detecting means for detecting the ON and OFF signals of the control means, and correcting means for correcting the target value of the target speed ratio based on the signal from the detecting means. The correcting means receives a signal from the detecting means. A shift control device for a continuously variable transmission, wherein the target value change amount is gradually corrected over a predetermined time or at a predetermined speed so that the shift speed in upshifting and downshifting is reduced.