JP4794124B2 - Vehicle control device - Google Patents

Description

  The present invention relates generally to a vehicle control device, and more particularly to a vehicle lockup control device having a torque converter with a lockup clutch.

  As a conventional automatic transmission for a vehicle, a hydraulic lockup clutch capable of mechanically directly connecting an input shaft and an output shaft thereof is provided in a torque converter, and the lockup clutch is engaged under a certain condition. Increasing the efficiency of torque converters has been done.

  Also, by using this lock-up clutch and engaging the lock-up clutch at the time of deceleration, the reverse driving force from the drive wheel side is transmitted to the engine side to suppress a sudden drop in engine rotation, so that the predetermined speed is reduced. The fuel cut is continued for a long time until the return rotational speed reaches the maximum, thereby improving the fuel consumption.

Japanese Patent Application Laid-Open No. 5-180328 discloses a state in which a deceleration lockup is activated and a lockup clutch cannot be engaged when the time spent in the lockup operation region when the accelerator pedal is on (accelerator pedal depression) is longer than a specified value. Discloses a control device for an automatic transmission that prevents unpleasant shocks caused by fuel cut.
JP-A-5-180328

  In the control apparatus for an automatic transmission described in the above-mentioned publication, it is determined whether or not the deceleration lockup can be operated according to the time spent in the lockup clutch operation region during the accelerator pedal-on traveling. However, in this method, it may not be possible to correctly determine whether the lockup is operable, and there may be a case where the unpleasant shock that is the purpose cannot be prevented.

  In order to compensate for this imperfection, it is necessary to make the determination value of the time spent in the lockup operation area longer than necessary. If the vehicle decelerates during this determination, the lockup clutch is actually engaged. Even when the fuel can be cut, the lock-up clutch is turned off and the fuel consumption may not be improved.

  That is, even in the lockup clutch operating region, it is often impossible to determine whether or not the lockup clutch is engaged according to the engine torque or the rotation state. For example, the lock-up clutch engagement shock is likely to be a problem in the low throttle region, and the lock-up clutch operating hydraulic pressure cannot be increased rapidly. Therefore, it takes time to engage the lock-up clutch even in the lock-up clutch operation region. It is difficult to determine whether or not the lockup clutch is operating in the time spent in the lockup clutch operating region.

  The control device disclosed in the above publication measures the time spent in the lockup clutch operating region when the accelerator pedal is on, but the lockup clutch remains on even when the accelerator pedal is off. Therefore, if the accelerator pedal is off and the lock-up clutch is not counted, the fuel cut opportunity is lost, which is disadvantageous in terms of fuel consumption.

  Therefore, an object of the present invention is to provide a vehicle control device that can accurately determine whether or not the lockup clutch can be securely engaged without a shock during deceleration traveling and can control the operation of the deceleration lockup. is there.

According to the first aspect of the present invention, a vehicle control system comprising: a torque converter with a lockup clutch provided between the engine and the automatic transmission; and a lockup control device for controlling the engagement state of the lockup clutch. A deceleration determination means for determining when the vehicle is decelerating, and a state in which a current hydraulic pressure of the lockup clutch is equal to or greater than a predetermined value at which the lockup clutch can be moved from a released state to an engaged state. First determination means for determining that a predetermined first predetermined time or more has elapsed, second determination means for determining whether or not lock-up clutch operation is prohibited, and whether or not the lock-up clutch operation region is in effect Third determination means for determining whether or not, and fourth determination means for determining whether or not the control command value is less than or equal to a command value corresponding to lock-up clutch off A deceleration lockup permission judging means for judging that a deceleration lockup control for fastening the lockup clutch with a predetermined fastening force when the vehicle is decelerating, wherein the hydraulic pressure is equal to or higher than the predetermined value. is determined not to have elapsed between the first place scheduled, determines that the lock-up clutch operating in the second determination means is determined not to be prohibited, a lock-up clutch operating region by said third determination means When the deceleration lockup permission determination means is permitted to perform deceleration lockup control, the fourth determination means determines that the value is equal to or less than a command value corresponding to the lockup clutch off, and the state is equal to or longer than a second predetermined time. A vehicle control device is provided that cancels the deceleration lock-up permission determination when the time has elapsed.

Here, the control command signal value is equal to or greater than a predetermined value is a value that allows the current control (hydraulic pressure) command signal value to move the lockup clutch from the released state to the engaged state in the lockup clutch control device. Yes, for example, 1.0 to 1.2 kgf / mm ² or more. The actual control oil pressure may be directly detected by a hydraulic sensor.

  The first predetermined time is a time required for the lockup clutch to move from the released state to the engaged state, and is 0.5 seconds, for example. Under these two conditions, the control state of the lockup clutch by the actual lockup control device can be reliably grasped, and the deceleration lockup control can be reliably performed without a shock.

According to the first aspect of the present invention, it is possible to suppress the engagement shock of the deceleration lockup clutch. According to the four conditions relating to the control command signal value, the control state of the lockup clutch by the actual lockup control device can be reliably grasped, and the deceleration lockup control can be reliably performed without a shock.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of an automatic transmission mounted on a vehicle according to an embodiment of the present invention and a control device for the automatic transmission, and an automatic transmission 6 is connected to a crankshaft 4 of an internal combustion engine 2.

  The automatic transmission 6 is connected to the crankshaft 4 and includes a torque converter 8 having a pump impeller 8a and a turbine runner 8b, a lockup clutch 10 for connecting the pump impeller 8a and the turbine runner 8b, and an output of the torque converter 8 And a hydraulic control mechanism 14 for controlling the operation of the lockup clutch 10 and the multi-speed transmission gear mechanism 12.

  The hydraulic control mechanism 14 includes an on-off type solenoid valve (hereinafter referred to as “A solenoid valve”) 14 a that switches between engagement and disengagement of the lockup clutch 10, and an A solenoid valve 14 a that is turned on, and the lockup clutch 10 is engaged. A duty control type solenoid valve (hereinafter referred to as “B solenoid valve”) 14b for controlling the engagement pressure when in the combined state, and a speed change actuator 14c for controlling the shift position (gear ratio) of the gear mechanism 12; Yes.

  The A solenoid valve 14a, the B solenoid 14b, and the speed change actuator 14c are connected to an electronic control unit (hereinafter referred to as "ECU") 16 for controlling an automatic transmission. The ECU 16 is connected via the A solenoid valve 14a and the B solenoid valve 14b. The engagement state of the lockup clutch 10 is controlled, and the shift position of the multi-stage transmission gear mechanism 12 is controlled via the transmission actuator 14c.

  The automatic transmission 6 is provided with a shift position sensor 18 for detecting the shift position SRTDG of the multi-stage transmission gear 12, and the detection signal is supplied to the ECU 16.

  The output of the engine 2 is transmitted from the crankshaft 4 through the torque converter 8, the gear mechanism 12, and the differential device 20 to the left and right drive wheels 22 and 24 in order to drive them. A vehicle speed sensor 26 for detecting the vehicle speed VP of the vehicle is provided on the output side of the automatic transmission 6, and the detection signal is supplied to the ECU 16.

  The engine 2 includes a throttle valve opening sensor 32 for detecting an opening θTH of a throttle valve 30 provided in the middle of the intake pipe 28, an engine water temperature sensor 34 for detecting an engine cooling water temperature TW, and an engine speed NE. An engine speed sensor 36 for detection is provided, and detection signals from these sensors are supplied to the ECU 16. The engine speed sensor 36 outputs a TDC signal pulse at a predetermined crank angle position every 180 degree rotation of the crankshaft 4 and supplies the TDC signal pulse to the ECU 16.

  Further, a throttle actuator 38 made of, for example, an electric motor is connected to the throttle valve 30, and this throttle actuator 38 is connected to the ECU 16. The ECU 16 is connected to an accelerator opening sensor 40 that detects the amount of depression of the accelerator pedal of the vehicle (hereinafter referred to as “accelerator opening”) APFZ, and the detection signal is supplied to the ECU 16.

  The ECU 16 controls the throttle valve opening θTH in accordance with the accelerator opening APFZ and the like. That is, in the present embodiment, the accelerator pedal and the throttle valve 30 are not mechanically connected, and the throttle valve opening θTH is controlled according to the accelerator opening AP and other operating conditions.

  The ECU 16 is further connected to a selection lever position sensor 42 for detecting a selection lever position for selecting an operation mode of the automatic transmission 6 and a brake switch 44 for detecting depression of a brake pedal. It is supplied to the ECU 16.

  The ECU 16 is connected to an engine control electronic control unit (not shown) that controls the amount of fuel supplied to the engine 2 (opening time of the fuel injection valve), ignition timing, and the like, and transmits control parameter information to each other. It is configured as follows.

  The ECU 16 shapes an input signal from the various sensors described above, corrects the voltage level to a predetermined level, and converts an analog signal value into a digital signal value, and a central processing circuit (CPU). Drive signals to the storage circuit composed of ROM and RAM for storing various calculation programs executed by the CPU, shift maps and calculation results described later, the A solenoid valve 14a, the B solenoid valve 14b, and the transmission actuator 14c. And an output circuit.

  The ECU 16 controls the engagement state, the shift position, and the throttle valve opening θTH of the lockup clutch 10 based on detection signals from various sensors. In addition, the process demonstrated with reference to a flowchart below is performed by CPU of ECU16.

  Referring to FIG. 2, a principle block diagram of the present invention is shown. The vehicle targeted by the control device of the present invention includes a torque converter 8 with a lock-up clutch provided between the engine 2 and the automatic transmission 6, and a lock-up control device 48 that controls the engaged state of the lock-up clutch 10. It has. The lockup control device 48 includes the A solenoid 14a and the B solenoid 14b shown in FIG.

  In the vehicle control device of the present invention, a state where the control command signal value to the engagement side of the lockup clutch 10 by the lockup control device 48 and the lockup control device 48 is not less than a predetermined value is determined in advance. First determination means 52 is included for determining that a predetermined first predetermined time or more has elapsed. The deceleration determination means 50 determines that the vehicle is decelerating when the throttle valve is off, for example.

The control command signal value is equal to or greater than a predetermined value is a value that allows the current control (hydraulic pressure) command signal value to move the lockup clutch from the released state to the engaged state in the lockup clutch control device. 1.0 to 1.2 kgf / mm ² or more.

  The first predetermined time is a time required for the lockup clutch to move from the released state to the engaged state, and is 0.5 seconds, for example. With these two conditions relating to the control command signal value, it is possible to reliably grasp the control state of the lockup clutch by the actual lockup control device, and to perform the deceleration lockup control reliably without shock.

  The vehicle control device further determines, based on the determination result of the first determination means 52, whether or not the deceleration lockup control for engaging the lockup clutch 10 with a predetermined engagement force can be permitted when the vehicle decelerates. A deceleration lockup permission determination means 56 is included. According to the present invention, the deceleration lockup control of the lockup clutch 10 is executed based on the determination result by the deceleration lockup permission determination means 56.

  Preferably, the vehicle control device further includes second determination means 54 for determining that the deviation between the actual slip ratio of the lockup clutch 10 and the target slip ratio is within a predetermined deviation. “Within a predetermined deviation” means, for example, a state where the deviation is within 10% and the control is stable. Then, the deceleration lockup permission determination means 56 determines whether or not the deceleration lockup control is permitted based on the determination results of the first determination means 52 and the second determination means 54.

  More preferably, the second determination means 54 elapses for a predetermined second predetermined time or more that the deviation between the actual slip ratio of the lockup clutch 10 and the target slip ratio is within a predetermined predetermined deviation. Determine what happened. Here, the second predetermined time is a time during which it can be determined that the control is stable, and is set to 2 seconds, for example.

  As a result, it is possible to grasp that the change of the driving state of the vehicle is not large and the control state of the lock-up clutch of the lock-up control device is not a transient state (for example, a state in which release and engagement are repeated). Since the stable state can be surely grasped, the deceleration lockup control can be reliably performed without a shock.

  Hereinafter, a vehicle control method according to an embodiment of the present invention will be described with reference to the flowcharts of FIGS. 3 and 4. FIG. 3 shows a processing flow of the deceleration lockup control. First, in step 10 (abbreviated as S10 in the drawing), it is determined whether or not the vehicle speed V is greater than V1. V1 is, for example, 30 to 40 km / h.

  If it is determined that the vehicle speed V is greater than V1, the routine proceeds to step 11 where it is determined whether or not the accelerator pedal is off. If the accelerator pedal is off, the routine proceeds to step 12 where it is determined whether or not the engine speed Ne is greater than Ne1. Here, Ne1 is, for example, 1200 to 1300 rpm, and is set slightly higher than the idling speed.

  If it is determined at step 12 that the engine speed Ne is greater than Ne1, the routine proceeds to step 13 where it is determined whether or not the input shaft speed NM of the automatic transmission 6 is greater than NM1. NM1 is, for example, 1200 to 1300 rpm.

  If it is determined in step 13 that the input shaft speed NM is greater than NM1, the process proceeds to step 14 to determine whether the deceleration lockup permission flag is 1, that is, whether the permission flag is set.

  If it is determined in step 14 that the deceleration lockup permission flag is 1, the routine proceeds to step 15 where the lockup control device 48 is operated to execute deceleration lockup control. On the other hand, if the determinations in steps 10 to 14 are negative, the process proceeds to step 16 and the process is terminated without performing deceleration lockup control.

  If the deceleration lockup control is performed when the determination in step 14 is negative, a shock is generated when the lockup clutch is engaged, or the lockup clutch cannot be engaged for a considerably long time.

  During this long period of time, the lock-up control device increases the hydraulic pressure in an attempt to engage the lock-up clutch, and a sudden increase in hydraulic pressure causes a large shock at the time of actual engagement. According to the deceleration lockup control of the present invention, such a fastening shock can be reliably suppressed.

Next, the deceleration lockup permission determination process will be described with reference to the flowchart of FIG. First, in step 20, it is determined whether or not the current hydraulic pressure of the lockup clutch is greater than or equal to a predetermined value. If it is equal to or greater than the predetermined value, the routine proceeds to step 21 where it is determined whether or not the timer 1 has elapsed a predetermined time. This predetermined time is set to 0.5 seconds, for example.

  If it is determined in step 21 that the predetermined time has elapsed, the process proceeds to step 22 to determine whether or not the deviation between the actual slip ratio of the lockup clutch and the target slip ratio is within a predetermined deviation. Determine whether.

  If it is determined in step 22 that the slip ratio deviation is within the predetermined deviation, the process proceeds to step 23 to determine whether or not the timer 2 has elapsed a predetermined time. The predetermined time of the timer 2 is set to 2 seconds, for example.

  If it is determined in step 23 that the timer 2 has elapsed, the process proceeds to step 24 to determine whether or not a deceleration lockup control command signal has been issued. If the determination in step 24 is affirmative, the process proceeds to step 25 to set the deceleration lockup permission flag to 1.

  That is, a deceleration lockup permission flag is set. The deceleration lockup permission flag obtained in step 25 is used in step 14 of the flowchart of FIG.

  If the determination in step 20 is negative, timer 1 is set in step 26, and timer 2 is set in step 27. These timers 1 and 2 are subtraction timers, respectively. As described above, timer 1 is set to 0.5 seconds, for example, and timer 2 is set to 2 seconds.

  If the determinations in steps 21 to 24 are negative, the process proceeds to step 28 to determine whether or not the operation of the lockup clutch is prohibited. That is, it is determined whether or not there is a failure in an AT-related part such as a solenoid or a sensor. If there is a failure, the operation of the lockup clutch is prohibited.

  When the operation of the lockup clutch is not prohibited, the routine proceeds to step 29, where it is determined whether or not the lockup clutch is in the operation region. If it is determined in step 29 that the lockup clutch is in the operating region, the process proceeds to step 30 to determine whether the deceleration lockup permission flag is 1 or not.

  When it is determined that the deceleration lockup permission flag is 1, the routine proceeds to step 31, where it is determined whether or not the hydraulic pressure command value is equal to or lower than the hydraulic pressure command value corresponding to the lockup clutch off. If the determination in step 31 is negative, the process proceeds to step 32 and the timer 3 is set to a predetermined time, for example, 1 second.

  If the determination in step 31 is affirmative, it is determined whether or not the timer 3 has elapsed a predetermined time, for example, whether or not 1 second has elapsed. If it is determined in step 33 that the timer 3 has elapsed, the process proceeds to step 34 to set the deceleration lockup permission flag to 0. On the other hand, if the determination in step 33 is negative, this process ends.

  In the deceleration lockup permission determination flow described above, the timer 2 may be omitted. In this case, it is preferable to set the predetermined time of the timer 1 to 2 seconds, for example.

It is a figure which shows the structure of the automatic transmission mounted in the vehicle which concerns on this invention embodiment, and its control apparatus. It is a block diagram which shows the principle structure of this invention control apparatus. It is a flowchart of the deceleration lockup control process of this invention embodiment. It is a flowchart of the deceleration lockup permission determination process of this invention embodiment.

Explanation of symbols

2 Engine 6 Automatic transmission 8 Torque converter 10 Lock-up clutch 12 Multi-speed gear mechanism 14 Hydraulic control mechanism 16 Electronic control unit (ECU)
26 Vehicle speed sensor 28 Intake pipe 32 Throttle valve opening sensor 36 Engine speed sensor 40 Accelerator opening sensor

Claims (1)

A vehicle control device comprising: a torque converter with a lock-up clutch provided between an engine and an automatic transmission; and a lock-up control device for controlling an engagement state of the lock-up clutch,
Deceleration determination means for determining when the vehicle is decelerated,
A first determination is made that the current hydraulic pressure of the lock-up clutch exceeds a predetermined value that allows the lock-up clutch to move from the released state to the engaged state for a first predetermined time or more. A determination means;
Second determination means for determining whether or not lock-up clutch operation is prohibited;
Third determination means for determining whether or not the lockup clutch is in an operation region;
Fourth determination means for determining whether or not the control command value is equal to or less than a command value equivalent to lock-up clutch off;
A deceleration lockup permission judging means for judging that a deceleration lockup control for fastening the lockup clutch with a predetermined fastening force during deceleration traveling of the vehicle can be permitted,
The hydraulic pressure is determined to the predetermined value or more states are not passed between the first place scheduled,
It is determined that the lock-up clutch operation is not prohibited by the second determination means,
It is determined by the third determination means that the lock-up clutch is operating,
When the deceleration lockup permission determination means is permitted to perform deceleration lockup control, the fourth determination means determines that the value is equal to or less than a command value corresponding to the lockup clutch off, and the state has elapsed for a second predetermined time or more. And a vehicle control device that cancels the deceleration lock-up permission determination.

Images