JPH02107865A - Speed change controller for continuously variable transmission - Google Patents

Abstract

PURPOSE:To accelerate a car in consideration of responsiveness at the time of low-speed acceleration and improve acceleration feeling by correcting the change gear speed based on the throttle opening change speed indicating the acceleration request of a driver and the car speed. CONSTITUTION:In the speed change control at the time of acceleration, the target change gear ratio is when an accelerator is depressed is set to the low- speed stage side, and the down-shift is performed so that the actual change gear ratio (i) follows it. The throttle opening change speed theta' is calculated by a throttle opening change calculating unit 61 based on the throttle theta, and the throttle opening change speed theta' and the car speed are inputted to an acceler ation request coefficient setting unit 60 to determine the acceleration request coefficient K1. The acceleration request coefficient K1 is set larger and the change gear speed is corrected to a larger value as the car speed is decreased and the throttle opening change speed is increased and the acceleration request is stronger. A car is accelerated with good responsiveness, and the acceleration performance and feeling matching the acceleration request of a driver can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a transmission control device that controls the transmission speed based on the gear ratio and rotational speed in a belt-type continuously variable transmission for vehicles. Regarding improving the feeling during acceleration.

[Conventional technology]

In this type of continuously variable transmission, it has been considered to perform speed change control so as to not only follow a transient state but also have good convergence so as to prevent overshooting, hunting, etc. For this reason, for example, the deviation between the target value of the target gear ratio and the actual value of the actual gear ratio.

It has been proposed that the shift speed is controlled by determining the manipulated variable as the shift speed using a correction element or the like. There is a tendency to further correct the target value and operation amount depending on various special driving conditions and the state of the engine or drive system to improve the feeling during acceleration.

When accelerating, the target gear ratio 1g is temporarily downshifted as the accelerator is depressed, as shown in Figure 5(a), and then gradually upshifted due to an increase in vehicle speed, etc., and the actual gear ratio l changes from this. The speed change speed is determined and controlled so as to follow the speed. At this time, the acceleration G as shown in Figure 5(C)
The state in which this acceleration G is generated greatly affects the acceleration feeling. That is, during acceleration, the driver senses the maximum acceleration Gap, which is the upper limit of the acceleration G, and the time T required to reach this maximum acceleration G-, and determines whether the accelerator depression speed matches the representative acceleration request. When the maximum acceleration Gl is large and the time T is short, the response is good and the acceleration is felt strongly, and when the driver's acceleration request is large at low speeds, creating such an acceleration state improves the feeling. Become.

On the other hand, if the maximum acceleration Gs and time T are in the opposite relationship, the smoothness will be improved and the increase in engine speed will be suppressed, allowing you to experience comfortable acceleration. improve. Therefore,
In particular, in order to improve the feeling during low-speed acceleration, it is desirable to correct the shift speed so that the actual gear ratio I follows the target gear ratio Is so as to satisfy the above-mentioned responsiveness.

Conventionally, in the speed change control of the above-mentioned continuously variable transmission, kickdown acceleration has been conventionally disclosed in Japanese Patent Laid-Open No. 59-2082, for example.
There is a prior art in Publication No. 53. Here, in the case of acceleration from a low speed or low load state, it is shown that the shift speed changes gradually at the beginning, and then increases stepwise after a predetermined period of time has elapsed.

[Problem to be solved by the invention]

By the way, in the prior art described above, if the shift speed toward the downshift side is reduced at the beginning of acceleration, the driving force is small and acceleration performance is impaired. Therefore, when the driver requests rapid acceleration such as kickdown, it is preferable to correct the vehicle using a technical concept opposite to that of the prior art.

The present invention has been made in view of these points, and its purpose is to improve the acceleration feeling by accelerating with emphasis on responsiveness so as to meet the driver's acceleration request during low-speed acceleration. An object of the present invention is to provide a speed change control device for a continuously variable transmission that can perform the following steps.

[Means to solve the problem]

In order to achieve the above object, the shift control device of the present invention provides a shift control system that calculates and controls a shift speed using at least a plurality of a target value and an actual value of a gear ratio, and a rate of change of the target value. The speed is corrected based on the throttle opening change rate indicating the driver's acceleration request and the vehicle speed.

The shift speed may be corrected by an increasing function with respect to the throttle opening change rate and by a decreasing function with respect to the vehicle speed.

[For production]

Based on the above configuration, the downshift during acceleration is controlled using the shift speed, and the lower the vehicle speed is and the faster the throttle opening change rate is, the stronger the acceleration request is, the faster the shift speed is corrected to a larger value, resulting in a response. The vehicle accelerates well and provides acceleration performance and feeling that meet the driver's acceleration requirements.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

Referring to FIG. 1, the overall configuration of a drive system that combines an electromagnetic clutch and a belt-type continuously variable transmission will be described. The engine 1 is connected to a continuously variable transmission 4 via an electromagnetic clutch 29, such as an electromagnetic powder type, and a forward/reverse switching device 3.
Group Nori Duction Gya5. Output shaft 6. The transmission is configured to be transmitted to drive wheels 9 via a differential gear 7 and an axle 8.

The electromagnetic powder clutch 2 has a drive member 2a on the engine crankshaft 10, and a driven member 2b on the input shaft 11 with a clutch coil 2C. Then, due to the clutch current flowing through the clutch coil 2C, both members 2a,
Electromagnetic particles are combined and accumulated in a chain in the gap between the parts 2b, and the resulting binding force variably controls clutch crossing and clutch torque.

The forward/reverse switching device 3 is configured in a synchronous meshing manner between an input shaft 11 and a transmission main shaft 12 by gears, a hub, or a sleeve, and has at least a forward position where the input shaft 11 is directly connected to the main shaft 12, and a forward position where the input shaft 11 is directly connected to the main shaft 12. 11 is reversed and transmitted to the main shaft 12.

The continuously variable transmission 4 has a main shaft 12 and a sub-shaft 13 arranged parallel to the main shaft 12. The main shaft 12 has a variable-boot interval primary pulley 14 equipped with a hydraulic cylinder 14a.
Similarly, a secondary pulley 5 is provided with a hydraulic cylinder 15a. Further, a drive belt 1B is wound around both pulleys 14 and 15, and both cylinders 14a and 15a
is configured in the hydraulic control circuit 17. Line pressure corresponding to the transmitted torque is supplied to both cylinders 14a and 15a to apply a pulley pressing force, and the primary pressure causes the drive belt to to wrap around the pulley 14.15 steplessly by changing the diameter ratio. It is configured to perform speed change control.

Next, the electronic control system of the electromagnetic powder clutch 2 and the continuously variable transmission 4 will be explained. Engine speed sensor 19 for engine l. Primary pulley rotation speed sensor 21 of continuously variable transmission 4. Secondary boolean rotation speed sensor 22. It has sensors 23 and 24 that detect the operating status of the air conditioner and choke. The operating shift lever 25 is mechanically connected to the forward/reverse switching device 8, and is equipped with a shift position sensor 2B that detects each range of reverse (R), drive (D), and sporty drive (Ds). have Further, the accelerator pedal 27 has an accelerator switch 28 for detecting the accelerator depression state, and a throttle opening sensor 29 for opening the throttle valve.

The various signals from the switches and sensors are input to the electronic control unit 20 and processed by software using a microcomputer or the like. Then, the clutch control signal output from the electronic control unit 20 is input to the electromagnetic clutch 2, and the shift control signal and line pressure control signal are input to the hydraulic control circuit 17 of the continuously variable transmission 4 to perform each control operation. There is.

Referring to FIG. 2, the electromagnetic clutch control system and continuously variable speed control system of the control unit 20 will be explained.

First, the electromagnetic clutch control system includes a reverse excitation mode determination section 32 in which signals of the engine speed Ne and the parking (P) and neutral (N) ranges other than R, D, and DS of the shift position sensor 26 are manually operated. , for example N e <
In the case of 30 Orpm or in the P or N range, it is determined to be the reverse excitation mode, and the output determination section 33 causes a minute current to flow in the opposite direction to the normal one. Then, the residual magnetism of the electromagnetic clutch 2 is removed and the electromagnetic clutch 2 is completely released. It also has an energization mode determining unit 34 into which the determination output signal of this reverse excitation mode determining unit 32, the depression signal of the accelerator switch 28, and the rotation speed (hereinafter referred to as vehicle speed V) signal of the secondary pulley rotation speed sensor 22 are input, The running state such as starting is determined, and this discrimination signal is sent to the starting mode current setting section 35. Drag mode current setting section 36. The direct connection mode current setting section 37 is manually operated.

The starting mode current setting unit 35 separately sets starting characteristics in relation to the engine rotation speed Ne, etc. in the case of normal starting or starting using an air conditioner or a choke. Then, throttle opening θ and vehicle speed V.

The clutch current is set by correcting the starting characteristics according to each driving range of R, D, and Ds. The drag mode current setting unit 36 determines a slight drag current when the accelerator is released at low vehicle speed in each of the R, D, and Ds ranges, and generates a drag torque in the electromagnetic clutch 2 to reduce play in the belt and drive system. , to perform a smooth start. In this mode, the current is set to zero until just before the vehicle stops after the clutch is released in the D range, to ensure coasting performance. 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 range 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, 38, and 37 are input to the output determining unit 33, and the clutch current is determined according to the instructions thereof.

Next, referring to the variable speed control system of the continuously variable transmission control, the primary pulley rotation speed Np and the secondary pulley rotation speed Ns of the primary pulley rotation speed sensor 21 and the secondary pulley rotation speed sensor 22 are sent to the actual speed ratio calculation unit 40. The actual gear ratio I is calculated manually using the actual gear ratio 1-Np/Ns. This actual gear ratio 1, the throttle opening θ of the throttle opening sensor 29, and the shift positions R and D of the shift position sensor 26.

Ds is input to the target primary boolean rotation speed search unit 41, and l is determined based on the shift pattern for each range of R, D, and Ds.
Target primary pulley rotation speed NP using the -θ map
Search for D. The target primary pulley rotation speed NPD and the secondary pulley rotation speed Ns are input to the target speed ratio calculating section 42, and the target speed ratio IS is calculated by Is-NPD/NS. Then, this target gear ratio IS is inputted to the target gear ratio change speed calculation unit 43, and the target gear ratio IS is
A target gear ratio change speed old s/dt is calculated based on the amount of change in s. Then, these actual gear ratios are 1. Target gear ratio Is,
Target gear ratio change speed dis/dt and coefficient setting section 44.
The coefficients Kl and 2 of 80 are input to the shift speed calculating section 45, and the shift speed old/dt is calculated as follows.

1 for old/dt- (is-1) + 2 for dis/dt In the above formula, 1s-1 is the control amount of the target and actual gear ratio deviation, and d1s/dt is the delay correction element of the control system. be.

The above-mentioned speed change speed old/dt and actual speed change ratio 1 are inputted to the duty ratio search section 46. Here, since the duty ratio of the manipulated variable is set according to the relationship D - f (dl/dt, 1), a map with a duty ratio of dl/di-1 is used for upshifts and downshifts. Searched. The value of the duty ratio of this operation amount is outputted to the shift speed control solenoid valve 48 of the hydraulic control circuit 17 via the drive unit 47.

Next, the line pressure control system for continuously variable transmission control will be described. Engine speed sensor 19. Throttle opening sensor 2
The engine torque retrieval unit 50 receives the engine rotational speed Ne of 9 and the throttle opening θ, and calculates the engine torque T from the torque characteristic map of θ-Ne. The engine torque T and the signal of the actual gear ratio l from the actual gear ratio calculation unit 40 are as follows:
The target line pressure PL is input to the target line pressure setting section 51 and is determined by the product of the required line pressure according to the engine torque and the actual gear ratio l.
Define d. On the other hand, since the maximum line pressure value changes as the pump discharge pressure changes depending on the engine speed, the maximum line pressure search unit 52 inputs the engine speed Ne and the actual gear ratio 1 in order to detect this fluctuation state. and N
Find the maximum line pressure P Lmax using the map of e-1. The target line pressure PLd and the maximum line pressure PL*aX are input to the pressure reduction value calculation unit 53, and the line pressure PLR is calculated as the ratio of the target line pressure PLd to the maximum line pressure PLsax, and this is input to the duty ratio search unit 54. Input it to determine the duty ratio according to the line pressure PLR.

The duty signal is configured to be outputted to the line pressure control solenoid valve 56 via the drive section 55.

Therefore, the correction means during low-speed acceleration in the above control system will be described.

First, in the equation for the shift speed old/dt calculated by the shift speed calculation unit 45 described above, the factor that determines the shift speed old/dt is (Is-1), a coefficient of 1, and the value of (ls-1). is inevitably determined by the target gear ratio Is and the actual gear ratio I during acceleration. Therefore, in order to correct the shift speed di/dt so as to match the driver's acceleration request during low-speed acceleration, it is sufficient to set the coefficient to 1 to match it. can be referred to as the acceleration request coefficient.

Here, the direct element of the acceleration request is the degree to which the driver presses the accelerator, that is, the throttle opening change rate σ,
If the throttle opening change rate d is large and the acceleration request is strong, the acceleration request coefficient may be set to a large value of 1. Further, since the acceleration request is stronger as the vehicle speed is lower, the acceleration request coefficient may be set to a larger value of 1 when the vehicle speed is low.

Therefore, a throttle opening change speed d is calculated using a throttle opening change speed calculation unit 6I that receives the throttle opening θ, and the throttle opening change speed 6 and the secondary pulley rotation speed Ns indicating the vehicle speed are accelerated. Request coefficient setting section 6G
is input to set the acceleration request coefficient to 1. That is, the acceleration request coefficient 1 is set as an increasing function for the throttle opening change rate σ and as a decreasing function for the vehicle speed, as shown in FIG. 3 based on the driver's acceleration request described above. It is something that will be done.

Next, the operation of the shift control device for the continuously variable transmission configured as described above will be explained.

First, power from the engine l corresponding to the depression of the accelerator is input to the primary pulley I4 of the continuously variable transmission 4 via the electromagnetic clutch 21 and the forward/reverse switching device 3, and the power is input to the primary pulley I4 of the continuously variable transmission 4.
B. The power shifted by the secondary pulley 15 is output, and this is transmitted to the drive wheels 9 to drive the vehicle.

During the above-mentioned driving, the target line pressure is set to be larger as the engine torque T is larger in the lower speed gear where the value of the actual gear ratio 1 is larger, and the corresponding duty signal is input to the solenoid valve 5B to generate the control pressure. By controlling the line pressure using the averaged pressure, the line pressure PL is increased. Then, as the shift to a high speed gear occurs, the actual gear ratio I
As becomes smaller and the engine torque T also becomes smaller, the line pressure PL is controlled to decrease by acting in the same way.In this way, the pulley pressing that corresponds to the torque transmitted by the drive belt 16 always exerts a force. do.

The line pressure PL is always supplied to the secondary cylinder 15a, and is supplied to the primary cylinder 14a by a speed change control valve (not shown) using the control pressure of the solenoid valve 48.
By supplying and draining oil to and from the engine, the speed change speed is controlled, and this will be explained below.

First, the primary pulley rotation speed sensor 21. Secondary pulley rotation speed sensor 22 and throttle opening sensor 2
The signals Np, Ns, and θ from 9 are read, and the actual gear ratio calculating section 40 of the control unit 20 calculates the actual gear ratio l.

Further, the target primary pulley rotation speed search unit 41 determines that the actual gear ratio is 1. The target primary pulley rotation speed NPD is once searched by a map based on the throttle opening degree θ, and the target speed change ratio calculation unit 42 calculates the target speed change ratio 1s corresponding to this target primary pulley rotation speed NPD.

These actual gear ratio I, target gear ratio Is, coefficient 1, and change rate dis/dt of target gear ratio change rate calculation unit 43
, using 2 as the coefficient, the shift speed calculation unit 45 calculates the shift speed old/
Find di. Then, the duty ratio is searched by the duty ratio search unit 4B based on the shift speed di/dt and the actual gear ratio I.

The duty signal is input to the solenoid valve 48 to generate a pulse-like control pressure, thereby repeatedly operating the speed change control valve in two positions: oil supply and oil drain. Here, for example, when the duty ratio becomes small, the shift speed control valve (not shown) operates for a longer time in the oil draining position due to the off time, and oil is drained from the primary cylinder 14a, thus downshifting. On the other hand, when the duty ratio increases, the operating time at the refueling position becomes longer due to the on-time, and the primary cylinder 14a is refueled, thereby upshifting. In this case, the speed change speed d1/
Since dt corresponds to a change in the duty ratio, when the shift speed d1/dt is small, the shift speed becomes slow because the change in the duty ratio is small and the flow rate change in the primary cylinder 14a is small. On the other hand, the shift speed di/
As dt increases, the change in the flow rate of the primary cylinder 14a increases due to a change in the duty ratio, and the shift speed becomes faster.

In this way, the gears are shifted steplessly by downshifting or upshifting while changing the gearshift speed over the entire gearshift range between the low gear and the high gear.

Next, the effect of the speed change control during acceleration will be described. When the accelerator is depressed, the target speed ratio Is is set to the lower gear side as shown in FIG. 4, and the actual speed ratio i is downshifted to follow this. At this time, the throttle opening change rate 6 is calculated by the throttle opening change rate calculation section 61 based on the throttle opening degree θ, and this throttle opening change rate δ and the vehicle speed are input to the acceleration request coefficient setting section 60 to accelerate the acceleration. Set the request coefficient to 1.

Therefore, when the throttle opening change speed 6 is large at low speed, the acceleration request coefficient is set to a large value of 1 according to the map shown in Fig. 3, so that the speed change speed old /
dt also increases. Therefore, at the time of downshifting, the acceleration G becomes negative once, but then rapidly increases and changes to produce the maximum acceleration Gm, thereby accelerating with the best response and meeting the driver's acceleration request. Furthermore, if the vehicle speed is higher than the above, or the throttle opening change rate 6 is lower than the above, and the driver's acceleration request is reduced, the acceleration request coefficient becomes 1 and the shift speed di/dt also decreases, as shown in FIG. As shown in (b), the change in acceleration G is also reduced, resulting in acceleration performance that meets this condition. Furthermore, if the acceleration request is small, set the acceleration request coefficient to 1 and the shift speed d.
l/dt, the acceleration G changes smoothly as shown in FIG. 4(e), resulting in acceleration performance that meets this condition.

Although one embodiment of the present invention has been described above, the shift speed di/dt may be corrected using an element other than 1 in the acceleration request coefficient. Alternatively, the acceleration request coefficient 1 may be divided into a throttle opening change rate coefficient and a vehicle speed coefficient, and both may be added or multiplied.

〔Effect of the invention〕

As described above, according to the present invention, in the shift control of the continuously variable transmission, the shift speed is corrected and controlled in accordance with the driver's acceleration request, so that the driver can enjoy a better acceleration feeling.

Furthermore, the throttle opening change speed and vehicle speed are used as elements of acceleration request, and the shift speed is corrected with an increasing function for the former and a decreasing function for the latter, so it emphasizes responsiveness during low-speed acceleration and improves feel as well as acceleration performance. can be improved.

Furthermore, since the coefficient of the deviation term between the target gear ratio and the actual gear ratio that determines the gear change speed is corrected as the acceleration request coefficient, the gear change speed can be easily and effectively corrected.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram showing an embodiment of a shift control device for a continuously variable transmission according to the present invention; Fig. 2 is a block diagram of an electronic control system; Fig. 3 is a diagram showing a map of acceleration request coefficients; Diagram (a>
C) is a diagram showing the acceleration state when the gear change speed is different in the low speed range, and FIG. 5 is a diagram illustrating the feeling during acceleration. 4...Continuously variable transmission, 20...Electronic control unit, 4
0...Actual gear ratio calculation unit, 42...Target gear ratio calculation unit, 43...Target gear ratio change speed calculation unit, 45...Shift speed calculation unit, 4B...Duty ratio search unit, 60・
...Acceleration request coefficient setting section, at...Throttle opening change speed calculation section Patent applicant Fuji Heavy Industries Co., Ltd. Agent Patent attorney Nobu Kobashi Ukiyo

Claims (3)

[Claims] (1) In a speed change control system that calculates and controls a speed change speed using at least a plurality of target values, actual values, and speeds of change of the target value of the speed ratio, the speed change speed is determined by a throttle opening change that indicates the driver's acceleration request. A speed change control device for a continuously variable transmission characterized by making corrections based on speed and vehicle speed. (2) The shift control device for a continuously variable transmission according to claim 1, wherein the shift speed is corrected by an increasing function with respect to the throttle opening change rate and by a decreasing function with respect to the vehicle speed. (3) Calculate the shift speed by multiplying at least the deviation between the target gear ratio and the actual gear ratio by a coefficient, and use the coefficient as an increasing function with respect to the throttle opening change rate,
2. The gear change control device for a continuously variable transmission according to claim 1, wherein the vehicle speed is corrected by a decreasing function.