JP2001115867A - Gear shift shock relieving device for continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a countermeasure from exercising an adverse influence as a result of a target change gear ratio being deviated from an actual change gear ratio when inertial torque is determined from a change ratio of a target change gear ratio to effect a shock countermeasure. SOLUTION: A target change gear ratio i* is decided at 31 and a target change gear ratio i* (FIL) after the preceding value i* (OLD) of the target change gear ratio is filter-processed is determined at 32. At 33, by multiplying a difference between a current target change gear ratio i* and a target change gear ratio i* (FIL) after filter-processing by a weighing coefficient, a target change gear ratio change amount Δi* (a time change ratio of a target change gear ratio i*) is calculated. At 34, inertial torque TN occasioned by a speed change is calculated from the Δi*. At 35, it is decided whether limitation of operation response of a speed change actuator is carried out. When no limitation is effected, at 36, initial torque TIN forms a value determined at 34 as it is. When limitation is effected, at 37, the inertial torque TIN is set to 0. Thereby, a speed change shock conuntermeasure carried out with an engine output being regulated by an amount equivalent to the inertial torque TIN is prohibited during a time in which limitation is effected on operation response of the speed change actuator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved device for reducing a shift shock of a continuously variable transmission by increasing or decreasing an engine output.

[0002]

2. Description of the Related Art In a continuously variable transmission represented by a V-belt type continuously variable transmission or a toroidal type continuously variable transmission, a target speed ratio is obtained from, for example, an engine required load and a vehicle speed. The gear shift control is performed so as to achieve the ratio. Therefore, for example, during acceleration in which the driver steps on the accelerator pedal to increase the required engine load, the target gear ratio is changed to be larger (to be a lower speed gear ratio), and the continuously variable transmission is made larger. When shifting to a low load operation in which the engine is downshifted (depressed downshift) to the target gear ratio and the driver returns the accelerator pedal to reduce the required engine load, the target gear ratio decreases (the gear ratio on the high-speed side). become)
In this manner, the continuously variable transmission is upshifted (foot-released upshift) to the reduced target gear ratio.

[0003] Such a shift causes an inertia torque due to a change in the transmission input-side rotation speed accompanying a change in the gear ratio, and a step-down downshift that increases the transmission input-side rotation speed is accompanied by the shift. A negative inertia torque causes a shift shock with a sense of pulling in torque and a shift response delay feeling.In addition, during a foot release upshift that reduces the transmission input side rotation speed, a positive inertia torque reverses the torque. A shift shock with a feeling of protrusion occurs.

[0004] In order to alleviate these shift shocks, measures have been conventionally proposed, for example, as described in Japanese Patent Application Laid-Open No. H11-20512. The technology described in this publication calculates an actual gear ratio, which is the ratio of the input / output rotation speeds of the continuously variable transmission, and then obtains the inertia torque associated with gear shifting from the time change ratio of the actual gear ratio to reduce shift shock. This contributes to engine output control.

However, when the actual speed ratio of the continuously variable transmission is obtained and the inertia torque accompanying the speed change is obtained from the time change ratio, it is necessary to calculate the input / output rotation speed of the transmission and the like in order to obtain the actual speed ratio. The main reason that the ratio must be calculated is that a relatively long time is required. There is concern that shock measures may be delayed. In this sense, it is preferable to use the target speed ratio used as described above in the speed change control for the calculation of the inertia torque, instead of the actual speed ratio of the continuously variable transmission.

According to the present invention, there is provided a shift shock reducing device for a continuously variable transmission, which determines an inertia torque accompanying a shift from a time change ratio of a target speed ratio based on the idea and contributes to engine output control for shifting shock reduction. It is assumed.

[0007]

However, it has been confirmed that such a type of shift shock reducing apparatus still has the following problems. The continuously variable transmission cannot shift unless it is transmitting power.Therefore, when the continuously variable transmission is stopped at a high vehicle speed ratio, the vehicle stops suddenly. If the rotation of the wheels is stopped before returning to the lowest speed ratio, the continuously variable transmission remains in the state of the high vehicle speed ratio.

When the vehicle is started by depressing the accelerator pedal in this speed change state, the continuously variable transmission can change gears. Downshifted towards ratio.
By the way, since the driver depresses the accelerator pedal relatively largely at the time of starting, if the above downshift is executed with a normal shift response (determined by hardware), the axle torque suddenly increases and the driver's expectation is increased. There is a possibility of the sudden start described above, and it is preferable to limit the response of the actuator that controls the shift of the continuously variable transmission so that the shift response avoids the sudden start.

[0009] One form of such a high start control to be described in reference to FIGS. 4, instantaneously t ₁ from the stopped state continuously variable transmission is in the high vehicle speed side gear ratio, vehicle starting operation is to raise the vehicle speed VSP And the target speed ratio i ^* is given in steps as shown by the solid line, and is first set to the intermediate speed ratio set before the lowest speed speed ratio, and the instant t
_The minimum speed ratio is set to ₂ . Here, the intermediate gear ratio is a gear ratio that does not cause sudden start as described above even when downshifting from a high vehicle speed side gear ratio with a normal gear response (determined by hardware). It can be determined in advance.

Accordingly, when shifting from the high vehicle speed side gear ratio to the intermediate gear ratio, as is apparent from the temporal change of the actual gear ratio i shown by the broken line, the response of the gear shift actuator is not limited, and the normal gear determined by hardware. The shift is advanced by the shift response. Shifting to the intermediate speed ratio does not limit the response of the shift actuator as described above and does not cause sudden start as in the above-described problem even if shifting is performed normally, and also reduces the response of the shift actuator. By not limiting, the shift delay to the lowest speed gear ratio can be reduced.

In the downshift from the intermediate speed ratio to the lowest speed ratio after the instant t _{2, as} apparent from the time-dependent change of the actual speed ratio i shown by the broken line, the sudden start causing the above-described problem may occur. In this case, the response of the shift actuator is limited so that the shift can proceed more slowly than the normal shift response determined by hardware, thereby eliminating the problem of sudden starting.

When the response of the speed change actuator is limited as after the instant t ₂ , the difference between the actual speed ratio i and the target speed ratio i ^* is inevitably increased. In a shock reduction device, that is, a shift shock reduction device of a continuously variable transmission that determines an inertia torque accompanying a shift from a time change ratio of the target speed ratio i ^* and contributes to engine output control for shifting shock reduction, the target speed ratio i ^* is Since the actual gear ratio i deviates greatly from the actual gear ratio and does not reflect the actual conditions of the transmission, the obtained inertia torque differs from the actual one, resulting in a problem that the gear quality is worse than in the case where no countermeasure for gear shift shock is taken. .

A first aspect of the present invention is to prevent such a problem from occurring.

A second object of the present invention is to easily solve the above-mentioned problem.

[0015] A third aspect of the present invention aims to surely solve the above-mentioned problem.

[0016]

SUMMARY OF THE INVENTION To achieve these objects, first, a shift shock reducing device for a continuously variable transmission according to the first invention is provided with an inertia torque associated with shifting of a continuously variable transmission used in combination with an engine. In a shift shock reduction device for a continuously variable transmission, which is calculated from a time change ratio of a target gear ratio used for shift control of a stepped transmission, and adjusts an engine output to reduce a shift shock due to the inertia torque, While limiting the response of the actuator that controls the shifting of the stepped transmission, the engine output is inhibited from being adjusted.

According to a second aspect of the present invention, there is provided a shift shock reducing device for a continuously variable transmission according to the first aspect, wherein a signal for limiting the response of the actuator is detected to inhibit the increase or decrease of the engine output. Is what you do.

According to a third aspect of the present invention, there is provided a shift shock reducing apparatus for a continuously variable transmission according to the first aspect, wherein a difference between an actual speed ratio of the transmission and the target speed ratio is equal to or greater than a set value. It is characterized in that the response is determined to be restricted and the increase or decrease of the engine output is prohibited.

[0019]

According to the first aspect of the invention, the inertia torque accompanying the shift of the continuously variable transmission is calculated from the time change ratio of the target gear ratio used for the shift control of the continuously variable transmission. Although the engine output is adjusted so as to be reduced, the engine output is inhibited while the response of the actuator that controls the shift of the continuously variable transmission is limited. When limiting the response of the shift actuator in this way, the target gear ratio used for calculating the inertia torque greatly deviates from the actual gear ratio as described above, and the calculated inertia torque does not match the inertia torque actually generated during gear shifting. However, the problem arises that the shift output quality is rather deteriorated as compared with the case where the shift shock reduction measures are not taken, because the engine output for reducing the shift shock becomes inappropriate and the shift output quality is deteriorated. As described above, since the shift shock reduction measure by adjusting the engine output is not performed, the occurrence of the problem can be eliminated.

According to the second aspect of the present invention, since the signal for limiting the response of the actuator is detected and the adjustment of the engine output is prohibited, the above problem can be easily solved.

In the third aspect, when the deviation between the actual transmission ratio of the transmission and the target transmission ratio is equal to or greater than a set value, it is determined that the response of the actuator is restricted, and the response of the engine output is determined. Since the shift shock countermeasures due to adjustments are prohibited, this prohibition is performed only when it is really necessary, so that the above-mentioned problem can be reliably solved. It is possible to eliminate the adverse effect that the shock reduction effect cannot be obtained.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a power train of a vehicle provided with a shift shock reduction device according to an embodiment of the present invention, and a control system thereof. The power train includes an engine 1 and a continuously variable transmission 2. The engine 1 is provided with a throttle valve 5 that is not linked to the accelerator pedal 3 operated by the driver but is separated from the accelerator pedal 3 and whose opening is electronically controlled by a step motor 4. By setting the rotational position corresponding to the degree (TVO ^* ) command, the throttle valve 5 is set to the target throttle opening degree TVO ^* , so that the output of the engine 1 can be controlled.

The continuously variable transmission 2 is a known V-belt type continuously variable transmission, and includes a primary pulley 7 which is drivingly connected to an output shaft of the engine 1 via a torque converter 6, and a secondary pulley 8 which is aligned with the primary pulley 7. And a V-belt 9 stretched between these pulleys. Then, a differential gear device 11 is drive-coupled to the secondary pulley 8 via a final drive gear set 10, and the wheels (not shown) are rotationally driven by these.

To change the speed of the continuously variable transmission 2, the primary
Each V groove of pulley 7 and secondary pulley 8
Of the flanges to be formed, one movable flange is
The V-groove width is narrowed relatively close to the fixed flange
To separate and widen the V-groove,
To the target gear ratio (i^* ) Step mode responding to command
Shift control valve operated by a shift actuator 12 such as
Primary pulley pressure P from 15 _pri And secondary
Pulley pressure P_sec Stepless by displacing
Primary pulley rotation speed N of transmission 2_pri And secondary
Pulley rotation speed N_sec Speed ratio i (= N
_pri / N_sec ) Is the target gear ratio i^* Steplessly to match
Shall be able to be accelerated.

The target throttle opening TVO ^* and the target speed ratio i ^* are calculated and obtained by the controller 13, respectively. Therefore, the controller 13 gives the depression position (accelerator opening) APS of the accelerator pedal 3.
And a throttle opening sensor 16 for detecting the throttle opening TVO.
, A signal from a primary pulley rotation sensor 17 for detecting the rotation speed (primary rotation speed) _Npri of the primary pulley 7, and a secondary pulley rotation for detecting the rotation speed (secondary rotation speed) _Nsec of the secondary pulley 8 inputs the signal from the sensor 18, a signal from a vehicle speed sensor 19 that detects a vehicle speed VSP, a signal from an engine speed sensor 20 for detecting the engine speed N _E.

Based on the input information, the controller 13 basically performs the usual shift control including the high start control described above with reference to FIG. The throttle opening degree control as described above and the throttle opening degree increasing / decreasing control (engine output increasing / decreasing control) for reducing the shift shock which the present invention aims at are performed. First, explaining the normal shift control, the accelerator opening APS, the throttle opening TVO, primary speed N _pri, secondary rotational speed N _sec, reads the vehicle speed VSP respectively, then primary speed N _pri and the secondary rotational speed N _sec And the actual speed ratio i, which is the ratio of the actual speed ratio i, is obtained by calculating i = N _pri / N _sec . Furthermore, from an accelerator opening APS and the vehicle speed VSP, searches the target primary rotation speed based on the shift map set in advance, by dividing the target primary rotation speed by the secondary rotation speed N _sec, the target primary A target gear ratio i ^* corresponding to the rotation speed is calculated. Then, by outputting the target gear ratio i ^* to the gear shift actuator 12, gear shift control is performed so that the actual gear ratio i changes toward the target gear ratio i ^* .

If it is necessary to limit the operation response of the speed change actuator as in the case of high starting described above with reference to FIG. 4, the controller 13 determines the target speed ratio i ^* separately as described above with reference to FIG. At the same time, the intended purpose can be achieved by limiting the operation of the speed change actuator 12 to the corresponding signal without relying on the response of the hardware.

It should be noted throttle opening (TVO) control is basically determined in accordance with the target throttle opening TVO ^* the accelerator pedal opening APS and the engine speed N _E,
FIG.
And the control program shown in FIG. 3 is executed to adjust the target throttle opening TVO ^* (output of the engine 1). First, at step 31 in FIG. 2, the target gear ratio i ^* is determined in the same manner as described above, and this is used to contribute to the gear shift control of the continuously variable transmission 2 and, on the other hand, to reduce the gear shift shock as described below. For the engine output control.

In the next step 32, the target gear ratio i after filtering the previous value i ^* (OLD) of the target gear ratio i
^* (FIL) is obtained, and in the next step 33, the current target gear ratio i ^* and the target gear ratio i ^* after the filtering process are performed ^.
(FIL) is multiplied by a weighting coefficient to calculate a target gear ratio change amount Δi ^* (a temporal change ratio of the target gear ratio i ^* ). In step 34, the inertia torque T _IN accompanying shift from the change amount of the target gear ratio .DELTA.i ^* calculated in a known manner, further at step 35, for example, operation of a shift actuator 12 as at the instant t ₂ after the 4 Check if the response is restricted. Here, when determining whether or not the restriction is performed, it is directly determined based on the presence or absence of an internal signal for performing the restriction, or a deviation between the target speed ratio i ^* and the actual speed ratio i is set. It can be determined based on whether or not the value is equal to or more than the value.

If it is determined in step S35 that the operation response of the speed change actuator 12 is not limited, the inertia torque T _IN is set in step S36.
In step 35, when it is determined that the operation response of the speed change actuator 12 is limited, the inertia torque T _IN is set in step 37.
It is set to 0 regardless of the value obtained in step 34.

In step 41 of FIG. 3, a target engine torque T _E ^* is obtained based on the Axel pedal opening APS and the engine speed N _{E. In} the next step 42,
The inertia torque T _IN determined in step 36 or 37 of FIG. 2 is passed through the upper and lower limiters so that the inertia torque T _IN does not exceed the upper and lower limit values. In the next step 43, the inertia torque T _IN is added to the target engine torque T _E ^* , and in a step 44, a target throttle opening TVO ^* for generating an engine output torque corresponding to the sum of the two is obtained. This is commanded to the step motor 4 in FIG.

In short, according to the throttle opening control, the time change ratio Δi ^* (step 33) of the target speed ratio i ^* used for the speed change control of the continuously variable transmission 2 (step 33) is equivalent to the inertia torque T _IN associated with the speed change (step 34). Further, the target engine torque _TE ^* (step 41) is corrected by the inertia torque T _IN (step 43), and the target throttle such that the corrected target engine torque ( _TE ^* + T _IN ) is generated. The opening of the electronic control throttle valve 5 is controlled so that the opening TVO ^* is equal to the opening TVO ^* .

Therefore, the shift shock caused by the inertia torque T _IN at the time of shifting can be reduced by adjusting the throttle opening TVO (engine output). In addition, instead of the actual speed ratio i of the continuously variable transmission, the shifting is performed. Since the target gear ratio i ^* used for the control is used for calculating the inertia torque T _IN , it is possible to take measures against a gear shift shock that requires agility without delay as required. Incidentally, while limiting the response of the speed change actuator 12 as at the instant t ₂ after the 4, since the target gear ratio used for calculating the inertia torque T _IN i ^* is be far apart as large as the actual gear ratio i, The calculated inertia torque T _IN is different from the actual inertia torque and the above-mentioned shift shock countermeasures are not effective as intended, and conversely the shift quality is worse than when no shift shock countermeasures are taken. Will be lost.

However, in the present embodiment, when it is determined in step 35 that the response of the speed change actuator 12 is limited, in step 37, the inertia torque T _{IN is set.}
Is set to 0 irrespective of the value calculated in step 34, the sum of the target engine torque T _E ^* and the inertia torque T _{IN obtained} in step 43 is the target engine torque T _IN.
E ^{* The} value is the same as that of the single unit, and the engine output adjustment control for reducing the shift shock is virtually prohibited. Therefore, when the engine output increase / decrease control for the shift shock countermeasure is performed, the shift shock countermeasure is performed while the response of the shift actuator 12 is limited such that the shift quality is deteriorated rather than not. It is possible to avoid the adverse effects of being forced.

In the above-described embodiment, the case where the continuously variable transmission is a V-belt type continuously variable transmission is described. However, the case where another type of continuously variable transmission such as a toroidal type continuously variable transmission is used. Of course, the idea of the present invention can be applied in the same manner.

[Brief description of the drawings]

FIG. 1 shows a power train of a vehicle equipped with a continuously variable transmission equipped with a shift shock reducing device according to an embodiment of the present invention.
FIG. 2 is a schematic explanatory view showing the integrated control system together with the integrated control system.

FIG. 2 is a flowchart showing an inertia torque calculation program executed by a controller in the embodiment.

FIG. 3 is a flowchart showing a shift shock reduction engine output adjustment control program executed by a controller in the embodiment.

FIG. 4 is an operation time chart showing one embodiment of a shift control in a case where the continuously variable transmission starts from a state where the speed ratio is set to a high vehicle speed side.

[Explanation of symbols]

 Reference Signs List 1 engine 2 continuously variable transmission 3 accelerator pedal 4 step motor 5 electronic control throttle valve 6 torque converter 7 primary pulley 8 secondary pulley 9 V-belt 10 final drive gear set 11 differential gear device 12 shift actuator 13 controller 14 accelerator opening sensor 15 Shift control valve 16 Throttle opening sensor 17 Primary pulley rotation sensor 18 Secondary pulley rotation sensor 19 Vehicle speed sensor 20 Engine rotation sensor

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masato Koga Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture (72) Inventor Satoshi Takizawa 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture 72) Inventor Shigeki Shimanaka 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Inside Nissan Motor Co., Ltd. 2F, Takara-cho, Kanagawa-ku, Kanagawa-ku, Nissan Motor Co., Ltd. F-term (reference)

Claims (3)

[Claims] An inertia torque associated with a shift of a continuously variable transmission used in combination with an engine is calculated from a time change ratio of a target gear ratio used for shift control of the continuously variable transmission,
In the shift shock reduction device for a continuously variable transmission configured to increase or decrease the engine output so as to reduce the shift shock due to the inertia torque, while limiting the response of the actuator that controls the shift of the continuously variable transmission, A shift shock reducing device for a continuously variable transmission, wherein the device is configured to prohibit increase and decrease of engine output. 2. The shift shock reducing device for a continuously variable transmission according to claim 1, wherein a signal for limiting the response of the actuator is detected to inhibit the increase or decrease of the engine output. 3. The engine output according to claim 1, wherein a response of the actuator is limited when a deviation between an actual transmission ratio of the transmission and the target transmission ratio is equal to or greater than a set value. A shift shock reducing device for a continuously variable transmission, wherein the shift shock reduction device is configured to prohibit adjustment of the speed.