JP2006090448A - Automatic transmission lockup control device - Google Patents

Abstract

An object of the present invention is to prevent the occurrence of "buzzing noise" while improving fuel efficiency by utilizing the characteristics of an automatic transmission.
In a lock-up state in which a lock-up clutch is engaged and an input / output shaft of a torque converter is directly connected, an accelerator operation amount (accelerator by a driver) even when the lock-up release speed is not less than rVSP. When the opening degree APO) exceeds the lockup release accelerator opening degree rAPO that is set according to the engine speed, or the engine torque (calculated value) is set according to the engine speed, the lockup release engine torque rTE. Is exceeded, the lock-up clutch is disengaged and switched to the converter state.
[Selection] Figure 2

Description

  The present invention relates to a lockup control device for an automatic transmission provided with a lockup mechanism, and in particular, reduces the fuel consumption (improves fuel consumption) by making use of the characteristics of the automatic transmission and generates a so-called “buzzing noise”. It relates to technology to prevent.

For example, Patent Document 1 discloses a lockup control device for an automatic transmission, and particularly, a technology related to a technique for releasing the engagement from a lockup clutch engaged state. In this apparatus, the frequency and release time of releasing the lockup clutch are reduced to improve the durability of the lockup clutch.
JP 200121032 A

  By the way, in order to improve fuel efficiency by taking advantage of the characteristics of automatic transmissions, especially continuously variable transmissions that can continuously change the gear ratio, the optimal fuel consumption line (or optimal fuel consumption range) of the engine is used. It is known that When designing a shift line based on such an idea, in a region where the required driving force is small and the engine load is small, the fuel consumption can be reduced (fuel efficiency can be improved) as the engine speed is reduced (see FIG. 7). ).

  On the other hand, as the engine rotation speed used decreases, so-called “buzzing noise” is more likely to occur in the passenger compartment due to vibration caused by torsional resonance between the engine and the transmission that uses the engine torque fluctuation as the excitation force. “Boom noise” is a phenomenon that occurs when the lock-up clutch in the torque converter is engaged (lock-up state), and absorbs torque fluctuations transmitted from the engine to the transmission by the damper in the lock-up clutch. This can be reduced.

Therefore, when trying to reduce the engine speed to be used in order to improve fuel efficiency, the damper in the lock-up clutch is made to have a low rigidity to prevent the “buzzing noise” from occurring. Can be considered.
However, generally, when the rigidity is reduced under a certain damper size, the allowable input torque of the damper tends to decrease (see FIG. 8), and a torque exceeding the allowable input torque may be input to the damper. Will occur. If a torque exceeding the allowable input torque is input to the damper, the damper can no longer fully exhibit its damping performance. This time, the torque exceeding the allowable input torque is input. This causes a new problem that a “buzzing sound” occurs.

For this reason, in order to improve fuel efficiency by taking advantage of the characteristics of automatic transmissions (especially continuously variable transmissions), lower the engine rotation speed and lower the rigidity of the damper and lower the rigidity of the damper. It is also necessary to increase the size of the damper according to the change to prevent the allowable input torque from decreasing.
In this way, in order to improve fuel efficiency by taking advantage of the characteristics of the automatic transmission and to prevent the occurrence of `` humming noise '', it is necessary to reduce the rigidity of the damper and increase the size of the damper. In particular, when the damper size is limited due to layout restrictions, etc., reducing the rigidity of the damper will not ensure sufficient input torque, resulting in lower engine rotation speed. There is a problem that fuel consumption cannot be improved sufficiently (ie, taking advantage of the characteristics of the automatic transmission).

  The present invention has been made paying attention to such problems, and effectively prevents the deterioration of the riding comfort due to the generation of “cuttering noise” while realizing the improvement in fuel efficiency by utilizing the characteristics of the automatic transmission. It is an object of the present invention to provide a lockup control device for an automatic transmission that can be used.

  Therefore, the present invention provides a lockup state in which the lockup clutch is engaged and the input / output shaft of the torque converter is directly connected in accordance with the driving state of the vehicle, and a converter state in which the engagement of the lockup clutch is released. , A lockup control device for an automatic transmission provided with a lockup mechanism capable of switching between, and in the lockup state, the accelerator operation amount by the driver exceeds a predetermined amount set according to the engine speed Sometimes, the lockup clutch is disengaged and switched to the converter state.

Further, in the lockup state, when the engine torque exceeds a predetermined torque value set according to the engine rotation speed, the lockup clutch is disengaged and switched to the converter state.
Furthermore, in the lockup state, when the accelerator operation amount by the driver exceeds a predetermined amount set according to the engine rotational speed, or a predetermined torque value where the engine torque is set according to the engine rotational speed Is exceeded, the lock-up clutch is disengaged and switched to the converter state.

  According to the lockup control device for an automatic transmission according to the present invention, in a predetermined operation state, the lockup clutch is engaged and the input / output shaft of the torque converter is directly connected, thereby eliminating the transmission loss of the torque converter and improving the fuel efficiency. In addition to the improvement, when there is a possibility that a “cuttering noise” may occur, the engagement of the lock-up clutch can be released to effectively prevent the “cuttering noise”.

  In this way, for example, to reduce fuel consumption by reducing the engine speed to be used, it is possible to prevent the “buzzing noise” that tends to occur in the low speed range by reducing the rigidity of the damper in the lockup clutch. At the same time, it is possible to prevent “bumping noise” generated due to a decrease in the allowable input torque accompanying the reduction in rigidity of the damper. As a result, it is possible to easily realize fuel efficiency improvement utilizing the characteristics of an automatic transmission (particularly a continuously variable transmission).

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, an automatic transmission 2 is provided on the output side of the vehicle engine 1. The automatic transmission 2 is capable of continuously changing a gear ratio (that is, a continuously variable transmission), and a torque converter 2a interposed on the output side of the engine 1 and a transmission coupled via the torque converter 2a. 2b and a hydraulic actuator 2c that performs coupling / disengaging operations of various transmission elements (such as a clutch) in the transmission 2b.

The hydraulic pressure for the hydraulic actuator 2c is controlled through various electromagnetic valves. Here, the shift solenoids 3a and 3b for the shift control and the lock-up control (that is, the lock-up clutch) are controlled. Only the lock-up solenoid 3c for fastening and releasing thereof is shown.
The control unit (C / U) 10 includes an accelerator opening sensor 11 that detects an accelerator opening (accelerator operation amount by a driver) APO, a vehicle speed sensor 12 that detects a vehicle traveling speed VSP, and a crankshaft ( A crank sensor 13 for detecting the rotational position (not shown), a water temperature sensor 14 for detecting the engine coolant temperature Tw, an air flow meter AFM 15 for detecting the intake air amount Qa, and a turbine rotation of the torque converter 2a. Detection signals from various sensors such as a turbine rotation speed sensor 16 for detecting the speed are input.

  Then, the C / U 10 performs predetermined arithmetic processing based on these input signals to execute fuel injection control and ignition timing control of the engine 1. Further, the optimum shift speed is determined by searching a table or the like based on the accelerator opening APO and the vehicle speed VSP, and the shift solenoids 3a and 3b are driven so that the actual shift speed becomes the determined shift speed. In addition to performing shift control and controlling the drive of the lock-up solenoid 3c according to the driving state of the vehicle, the lock-up clutch is engaged and the input / output shaft of the torque converter 2a is directly connected to the “lock-up” "Status" and "Converter status" where the lock-up clutch is disengaged.

FIG. 2 is a flowchart showing lock-up control according to the present embodiment that is executed by the C / U 10, and is executed at predetermined intervals.
In S11, the driving state of the vehicle (accelerator opening APO, vehicle speed VSP, engine speed Ne, etc.) is read.
In S12, it is determined whether or not a lockup flag (L / Up flag) is set. If the L / Up flag = 1, the process proceeds to S13. If the L / Up flag = 0, the flow ends. This L / Up flag is set to “1” when in the lock-up state, that is, when the vehicle operation state (accelerator opening APO and vehicle speed VSP) enters the lock-up region from the non-lock-up region. Is set to “0” when the vehicle is in the non-lock-up region (see FIG. 3).

In S13, it is determined whether or not the vehicle speed VSP is greater than a preset lockup release vehicle speed rVSP (for example, 20 km / h) (see FIG. 4). If VSP> rVSP, the process proceeds to S14 as it is (while being locked up), and if VSP ≦ rVSP, the process proceeds to S20.
In S14, a table set in advance according to the engine speed Ne (hereinafter referred to as “L / Up release accelerator opening table”) is searched to set the lockup release accelerator opening rAPO. The lock-up release accelerator opening rAPO is an accelerator opening that does not generate a “humming noise” at each engine rotation speed Ne because of the relationship between the engine torque TE, the engine rotation speed Ne, and the accelerator opening APO as shown in FIG. It is set as an upper limit value (or a value in the vicinity thereof). In the present embodiment, the lock-up release accelerator opening rAPO is set to a smaller value as the engine speed is lower, as shown in the L / Up release accelerator opening table in FIG. However, this is due to the fact that “low noise” tends to occur as the engine speed decreases.

In S15, it is determined whether or not the detected accelerator opening APO is equal to or smaller than the lockup release accelerator opening rAPO. If APO ≦ rAPO, the process proceeds directly to S16, and if APO> rAPO, the process proceeds to S20.
In S16, engine torque (calculated value) TE is read. The engine torque TE is calculated based on the intake air amount Qa. For example, the engine torque TE is converted into the engine torque TE using a preset intake air amount-torque conversion map or the like. Applicable.

  In S17, a table preset in accordance with the engine speed Ne (hereinafter referred to as “L / Up release engine torque table”) is searched to set the lockup release engine torque rTE. As shown in FIG. 5, the lock-up release engine torque rTE is the upper limit value (or a value in the vicinity thereof) of the engine torque at which no “humming noise” is generated at each engine rotational speed Ne, and almost “humming noise” is generated. It is set so as to correspond to the region (hatched portion in FIG. 5).

  As shown in FIG. 5, in the present embodiment, the low-speed region where the engine rotational speed Ne1 is equal to or lower is set as the “humming noise” generation region. This is because in a region where the engine rotational speed is high, it is considered that “buzzing noise” does not occur or “buzzing noise” does not matter (even if it occurs). The maximum improvement in fuel consumption is ensured (the case where the lock-up clutch is released in the lock-up region is minimized).

  Further, in the present embodiment, the lockup release engine torque rTE is (almost) constant at an engine speed Ne1 or lower. However, as described above, the “humming noise” is more likely to occur as the engine speed Ne is lower. Alternatively, the lockup release engine torque rTE may be set to be smaller as the engine rotational speed Ne is lower (determined by an experiment or the like as appropriate).

In S18, it is determined whether or not the engine torque (calculated value) TE exceeds the lockup release engine torque rTE. If TE> rTE, the process proceeds to S19. If TE ≦ rTE, this flow is finished as it is (that is, in the lock-up state).
In S19, the L / Up release accelerator opening table is updated. That is, when TE> rTE, the accelerator opening APO at that time is learned as the lock-up release accelerator opening rAPO at the engine speed Ne at that time, and the table value is updated. For example, when the L / Up release accelerator opening table shown in FIG. 6 is set, the engine torque calculation value TE is set when the engine speed Ne = 1200 (rpm) and the accelerator opening APO = 9 (deg). When the lockup release engine torque rTE is exceeded, the lockup release accelerator opening rAPO at the corresponding engine speed Ne = 1200 (rpm) is set to 9 (deg) in the L / Up release accelerator opening table. (Refer to the outside of the frame in FIG. 6).

In S20, the lockup clutch is disengaged and switched from the lockup state to the converter state (note that the L / Up flag is set to “0”).
Here, in the above flow, when the engagement of the lockup clutch is released based on the engine torque (calculated value) information, the accelerator opening APO at that time is learned, that is, the accelerator opening APO and the engine speed at that time are learned. The L / Up release accelerator opening table value is updated based on Ne (S18 → S19). This is to prevent “buzzing noise” that occurs due to component variations and changes in component characteristics over time, etc., based on the determination based only on the accelerator opening information (without waiting for the engine torque calculation result). It is. In other words, even when there is a variation in components, a change in component characteristics with time, etc., the occurrence of “buzzing noise” in a steady state can be prevented by determination based on engine torque (calculated value) information. (S18 → S19 → S20), it is difficult to sufficiently prevent the generation of a transient “boom sound”. Therefore, by performing learning control of the L / Up release accelerator opening table (value) as described above, the determination result based on the engine torque (calculated value) information is reflected in the determination based on the accelerator opening information, thereby making a transient. This makes it possible to prevent the occurrence of typical “buzzing noises”.

The embodiment described above has the following effects.
In the locked-up state, the L / Up release accelerator opening table is searched based on the engine speed Ne, the L / Up release accelerator opening rAPO corresponding to the engine speed is set, and the set L / Up release accelerator is opened. The degree rAPO and the detected accelerator opening APO (accelerator operation amount by the driver) are compared (S13). When the detected accelerator opening APO exceeds the L / Up release accelerator opening rAPO, the lockup clutch is released and switched to the converter state (S15 → S20). Even when the damper is rigid but has a small allowable input (when the damper size cannot be increased), it is possible to avoid a situation where torque exceeding the allowable input is input to the damper. This prevents the “buzzing noise” that occurs on the low rotation side due to the low rigidity of the damper, and also effectively prevents the “booming noise” that occurs when a torque exceeding the allowable input torque is input. it can. In the case where the accelerator operation and the throttle are linked, the throttle opening may be used instead of the accelerator opening.

Here, since the “buzzing noise” tends to be generated more easily as the engine speed is lower, the L / Up release accelerator opening rAPO is set smaller as the engine speed is lower. As a result, the lockup can be released only when necessary at each engine rotation speed, so that the fuel efficiency improvement effect by the lockup can be ensured to the maximum.
Further, in the lock-up state, the L / Up release engine torque table is set based on the engine rotation speed, the L / Up release engine torque rTE corresponding to the engine rotation speed is set, and the set L / Up release engine torque rTE is set. And the read engine torque TE are compared (S18). Then, when the read engine torque TE exceeds the L / Up release engine torque rTE, the engagement of the lockup clutch is released to switch to the converter state (S18 → S19 → S20). The situation where torque exceeding the allowable input is input can be avoided more reliably. Here, it is assumed that the read engine torque is calculated based on the intake air amount, and the L / Up release engine torque rTE is lower as the engine speed is lower, as in the case of the L / Up release accelerator opening rAPO. Although it is desirable to set a small value, it may be constant in a low rotation region below a predetermined rotation speed. In this way, control can be simplified.

  Further, in the lock-up state, when the detected accelerator opening APO exceeds the L / Up release accelerator opening rAPO set according to the engine rotation speed, or the read engine torque TE depends on the engine rotation speed. If the set L / Up release engine torque rTE is exceeded, the lock-up clutch is released and switched to the converter state (S15, S18 to S20). Even if there is a shift in the L / Up release accelerator opening rAPO due to component variations or changes in component characteristics over time, etc., while preventing the occurrence of “buzzing noise” promptly, the determination based on the engine torque information It is possible to reliably prevent the occurrence of “buzzing noise”.

  In this case, when the lockup clutch is released based on the determination based on the engine torque information and switched to the converter state, the L / Up release is performed based on the engine rotational speed Ne and the accelerator opening APO at that time. Update the accelerator opening table. As a result, the accuracy of determination based on the accelerator opening information is improved, and it is possible to quickly prevent the occurrence of a transient “boom sound”.

It is a system configuration figure of one embodiment of the present invention. It is a flowchart which shows the lockup control which concerns on embodiment. It is a figure which shows the converter state-> lockup state switching line (lockup line) which concerns on embodiment. It is a figure which shows the lockup state-> converter state switching line (lockup cancellation | release line) which concerns on embodiment. FIG. 6 is a characteristic diagram showing a relationship between engine rotation speed, engine torque, and accelerator opening, and a “boom sound” generation region. It is a figure which shows an example of a L / Up cancellation | release accelerator opening table. It is a characteristic view which shows an engine speed, an engine torque, and an optimal fuel consumption line. It is a figure for demonstrating the fall of the allowable input torque by damper rigidity reduction.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Automatic transmission, 2a ... Torque converter, 2b ... Transmission, 2c ... Hydraulic actuator, 3a, 3b ... Shift solenoid, 3c ... Lock-up solenoid, 10 ... Control unit (C / U), 11 ... Accelerator opening sensor, 12 ... Vehicle speed sensor, 13 ... Crank sensor, 14 ... Water temperature sensor, 15 ... Air flow meter (AFM), 16 ... Turbine rotational speed sensor

Claims (7)

A lock-up that can be switched between a lock-up state in which the lock-up clutch is engaged and the input / output shaft of the torque converter is directly connected, and a converter state in which the lock-up clutch is released according to the driving state of the vehicle. A lockup control device for an automatic transmission equipped with a mechanism,
In the lock-up state, when the accelerator operation amount by the driver exceeds a predetermined amount set according to the engine speed, the lock-up clutch is released and switched to the converter state. A lockup control device for a transmission.   2. The lockup control device for an automatic transmission according to claim 1, wherein the predetermined amount is set smaller as the engine speed is lower. A lock-up that can be switched between a lock-up state in which the lock-up clutch is engaged and the input / output shaft of the torque converter is directly connected, and a converter state in which the lock-up clutch is released according to the driving state of the vehicle. A lockup control device for an automatic transmission equipped with a mechanism,
In the lockup state, when the engine torque exceeds a predetermined torque value set in accordance with the engine rotation speed, the lockup clutch is disengaged and switched to the converter state. Lockup control device.   4. The lockup control device for an automatic transmission according to claim 3, wherein the predetermined torque value is set smaller as the engine speed is lower.   5. The lockup control device for an automatic transmission according to claim 3, wherein the engine torque is calculated based on an intake air amount. A lock-up that can be switched between a lock-up state in which the lock-up clutch is engaged and the input / output shaft of the torque converter is directly connected, and a converter state in which the lock-up clutch is released according to the driving state of the vehicle. A lockup control device for an automatic transmission equipped with a mechanism,
In the lock-up state, when the accelerator operation amount by the driver exceeds a predetermined amount set according to the engine rotation speed, or the engine torque exceeds a predetermined torque value set according to the engine rotation speed In some cases, the lockup control device for an automatic transmission is configured to release the engagement of the lockup clutch and switch to the converter state.   When the engine torque exceeds the predetermined torque value and the lockup clutch is disengaged and switched to the converter state, the engine rotation speed is determined based on the engine rotation speed and the accelerator operation amount at that time. The automatic transmission lockup control device according to claim 6, wherein the predetermined amount set in accordance with is updated.