JPH049940B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a control method for an automatic transmission used in a vehicle such as an automobile, and particularly to an idle operation control method that performs creep reduction control and hill hold control. 2. Description of the Related Art Automatic transmissions used in vehicles such as automobiles generally include a hydraulic torque converter that receives rotational power from an internal combustion engine, and a plurality of frictional engagement devices that receive rotational power from the hydraulic torque converter. It has a planetary gear type gear transmission that can be switched between a plurality of gears by engagement and disengagement, and the gear transmission has a predetermined shift pattern according to the vehicle speed and the amount of depression of the accelerator pedal. Therefore, the gears can be changed. Conventionally, in the automatic transmission for vehicles as described above, when the manual shift range is set to a driving range such as the D range, the accelerator pedal is released and the vehicle speed is substantially zero. In other words, even during idling, the gear transmission does not go into a neutral state and is set to the first gear, so that the vehicle starts with excellent responsiveness to the depression of the accelerator pedal. However, if the gear transmission is set to the first gear during idling operation, the output of the internal combustion engine is transmitted to the forward travel input member of the gear transmission via the hydraulic torque converter, which causes idling vibration. In order to bring the vehicle to a complete stop, the brake pedal must be pressed relatively hard to activate the vehicle travel brake, and the hydraulic torque converter is dragged at this time. It is known that fuel economy during idling operation deteriorates due to this, and the temperature of the hydraulic fluid in the hydraulic torque converter increases. In view of the above-mentioned problems, in order to keep the gear transmission in a neutral state or equivalent to a neutral state during idling operation when the vehicle is substantially stopped, the output member of the hydraulic torque converter of the friction engagement device of the gear transmission is used. Release the so-called forward clutch that selectively connects the input member of the gear transmission with the input member for forward travel of the vehicle, or set the engagement pressure of the forward clutch to a value lower than when the forward gear is achieved, causing the forward clutch to slip. The shift brake that prevents the vehicle from moving backward is engaged, and the output torque of the hydraulic torque converter is prevented from being transmitted to the forward travel input member of the gear transmission, thereby reducing creep. 2. Description of the Related Art Automatic transmissions for vehicles have already been proposed that include a control device that performs hill hold control, which prevents the vehicle from inadvertently reversing on a slope or the like due to engagement of the brake. This is shown, for example, in Japanese Patent Application Laid-Open No. 58-207553. The automatic transmission for vehicles of the prior application as described above has achieved the intended purpose, and in this automatic transmission for vehicles, idle vibration is reduced, the occurrence of creep is prevented, and the brake pedal can be depressed strongly. In most cases, the vehicle will come to a complete stop, and by eliminating the drag of the hydraulic torque converter, fuel economy during idle operation will be improved and the temperature of the hydraulic fluid in the hydraulic torque converter will increase. This also prevents the vehicle from inadvertently backing up on a slope, etc., and makes it easier to start the vehicle on a slope. Problems to be Solved by the Invention As described above, creep reduction control and hill hold control are performed during idling when the throttle opening is below a predetermined value and the vehicle speed is below a predetermined value. is sometimes useful for easy driving, and for example, when driving at a slow pace in traffic jams, it produces the effect of moving the vehicle forward at a low speed even if no particular accelerator operation is performed. In contrast, creep reduction control is generally not selectively executed at the driver's will using a manual select switch operated by the driver, but this is cumbersome to operate, and There is a risk that the manual settings may not be set appropriately by the driver. The present invention provides a vehicle that detects the driver's intention regarding the presence or absence of creep based on the operating state of the brake for braking the vehicle, determines whether to perform creep reduction control, and appropriately performs hill hold control in connection with this. The purpose of the present invention is to provide a method for controlling automatic transmissions during idle operation. Means for Solving the Problems According to the present invention, the present invention provides a hydraulic torque converter and a gear that can be switched between a plurality of gears by engaging and disengaging a plurality of frictional engagement devices. a forward clutch that selectively connects the output member of the hydraulic torque converter and the forward travel input member of the gear transmission; a one-way clutch that cooperates with the forward clutch to achieve the first gear; and a shift brake that cooperates with the one-way clutch to prevent the output shaft of the gear transmission from rotating in the backward direction of the vehicle. In the idling operation control method of an automatic transmission for a vehicle, the manual shift range is set to the forward driving range and the vehicle is in idling operation when it is substantially stopped. It is detected that the brake for braking the vehicle is operating, and when all three conditions are met, the engagement pressure of the forward clutch is set to a value lower than the value when the forward gear is achieved. The shift brake is engaged, and in this braking execution state, it is detected that the braking operation of the vehicle travel braking brake is released and that the accelerator pedal is depressed, and the vehicle When the braking action of the traveling brake is released, the engagement pressure of the forward clutch is increased to a value when a forward gear is achieved, and when the accelerator pedal is depressed, the shift brake is released. This is achieved by an idle operation control method characterized by: Effects and Effects of the Invention According to the idle operation control method for a vehicle automatic transmission according to the present invention, the manual shift range is set to D.
When the vehicle is set to a forward travel range such as a range, and the vehicle is idling, and the vehicle is substantially stopped, and the vehicle travel braking brake is operating, that is, when the brake pedal is depressed, the vehicle is not driven. When a person wants to completely stop the forward movement of the vehicle, the engagement pressure of the forward clutch is set to a value lower than when the forward gear is achieved, causing the forward clutch to slip, and the hydraulic torque converter is activated. The output torque is prevented from being transmitted to the forward travel input member of the gear transmission, ie, creep reduction control is performed, thereby reducing idle vibration and preventing the occurrence of creep. Further, at this time, the shift brake is engaged, and the output shaft of the gear transmission is prevented from rotating in the backward direction of the vehicle due to the cooperative action of the shift brake and the one-way clutch, that is, hill hold control is performed. This allows the vehicle to drive when stopped on an uphill slope, even if the vehicle travel braking brake is not operated reliably, that is, the brake pedal is not strongly depressed, or the parking brake is not tightened reliably. This prevents people from retreating against their will. The engagement pressure of the forward clutch at this time may be substantially zero, but it should be at a value that causes the forward clutch to slip so that the next forward clutch is engaged quickly. It is preferable. Under the anti-creep control condition as described above,
When the braking action of the vehicle running control brake is released, the shift brake remains engaged and the forward clutch is in an engaged state where it can transmit torque, so the creep reduction control is released and gear shifting is performed. The device now achieves a higher gear than first, which prevents the vehicle from continuing to move backwards, but there is a very slight creep that prevents the accelerator pedal from being depressed. In both cases, the vehicle will move forward at an extremely low speed, and driving in traffic jams will become easier by simply operating the brakes. In addition, at this time, it is possible to configure the system so that an engine braking effect is obtained, so that even if the braking action of the vehicle braking brake is released when going downhill, the engine braking effect will prevent the vehicle from rapidly descending the slope. . When the accelerator pedal is then depressed, the shift brake is released and the hill hold control is canceled.
The gear transmission now achieves the first gear,
The vehicle is started. Since re-starting from the above-mentioned state, that is, a state in which the brake pedal is depressed, is normally performed by first releasing the brake pedal and then depressing the accelerator pedal, the idling control method according to the present invention As mentioned above, when the brake pedal is released, only the creep reduction control is canceled and the vehicle becomes ready to start while remaining in the hill hold control state, and then only when the accelerator pedal is depressed. Hill hold control is canceled and the vehicle starts in first gear.
This prevents the vehicle from suddenly moving backwards when the brake pedal is released, and also allows the vehicle to start smoothly. In addition, in the above-mentioned control, the detection that the vehicle speed is substantially stopped and the internal combustion engine is idling is based on the vehicle speed and the throttle opening of the engine intake system, or the vehicle speed and the engine rotation speed. It's good that it's being done. EXAMPLES The present invention will now be described in detail by way of examples with reference to the accompanying drawings. FIG. 1 schematically shows the structure of an automatic transmission for a vehicle to which the idle operation control method according to the present invention is applied. The automatic transmission 1 includes a three-element, one-stage, two-phase general hydraulic torque converter 2 with a direct coupling clutch, which has a pump impeller 3, a turbine impeller 4, a stator impeller 5, and a direct coupling clutch 6, and an auxiliary transmission device. The pump impeller 3, which is an input member of the hydraulic torque converter 3, is drivingly connected to the output shaft 101 of the internal combustion engine 100, and the turbine impeller 3, which is the output member of the hydraulic torque converter 2, is connected to the output shaft 101 of the internal combustion engine 100. The wheel 4 is drivingly connected to an input shaft 9 of a gear transmission 7, and an output shaft 8 of the gear transmission 7 is drivingly connected to drive wheels (not shown) of the vehicle via a differential gear. The gear transmission 7 has a sub-gear transmission 10 and a main gear transmission 11 in series with each other. The auxiliary gear transmission 10 includes a sun gear 12, a ring gear 13 provided concentrically with the sun gear 12,
A planetary pinion 14 that is located between the sun gear 12 and the ring gear 13 and meshes with them, a carrier 15 that rotatably supports the planetary pinion 14, and a one-way clutch F ₀ that prevents the carrier 15 from rotating to the left with respect to the sun gear 12. 16 and
An OD clutch C ₀ 17 that selectively connects the sun gear 12 and the carrier 15, and an OD that selectively fixes the sun gear 12 to the transmission case.
Brake B ₀ 18 and carrier 15
is drivingly connected to the input shaft 9, and is connected to the OD clutch 17.
By selectively engaging the OD brake 15, it is possible to switch between two gears. The main gear transmission 11 includes a front sun gear 20 and a rear sun gear 21 connected to each other by an intermediate shaft 19, a front ring gear 22 provided concentrically with the front sun gear 20, and a rear ring provided concentrically with the rear sun gear 21. gear 23
, a front planetary pinion 24 located between the front sun gear 20 and the front ring gear 22 and meshed with them; and a rear planetary pinion 25 located between the rear sun gear 21 and the rear ring gear 23 and meshed with both. , a front carrier 26 rotatably supporting the front planetary pinion 24, and a rear planetary pinion 25.
A rear carrier 27 rotatably supported, and a front ring gear 22, which is an input member for forward running of the main gear transmission 11, are selectively connected to the ring gear 13, which is an output member of the auxiliary gear transmission 10, in a torque transmission relationship. forward clutch C ₁ 28,
A direct clutch C ₂ 29 that selectively connects the intermediate shaft 19 and the ring gear 13 in a torque transmission relationship.
and a shift brake B ₁ 30 for selectively fixing the intermediate shaft 19 to the transmission case.
It has another shift brake B ₂ 31 that selectively fixes the rear carrier 27 to the transmission case, and a one-way clutch F ₁ 32 that locks the rear carrier 27 from rotating counterclockwise. ring gear 2
3 is drivingly connected to the output shaft 8, and the plurality of clutches and the plurality of brakes are engaged and released in predetermined combinations, thereby providing a plurality of gears, three forward speeds and one reverse speed. It is now possible to switch between The gear transmission 7 is constructed by the clutches and brakes of the auxiliary gear transmission 10 and the main gear transmission 11 being engaged and released according to the table shown below. A plurality of gears, including five forward gears including an overdrive gear and one reverse gear, are selectively achieved by the cooperative action of the main gear transmission 11 and the main gear transmission 11.

[Table] 2nd speed ○ × × × ○ ○ △ ×

Claims (1)

[Scope of Claims] 1. A hydraulic torque converter comprising a hydraulic torque converter and a gear transmission that is switched between a plurality of gears by engaging and disengaging a plurality of frictional engagement devices, wherein the plurality of frictional engagement devices a forward clutch that selectively connects the output member of the hydraulic torque converter and the forward travel input member of the gear transmission;
a one-way clutch that cooperates with the forward clutch to achieve the first gear by a rotation blocking action; and a one-way clutch that cooperates with the one-way clutch to prevent the output shaft of the gear transmission from rotating in the direction in which the vehicle moves backward. In a method for controlling an automatic transmission for a vehicle during idling operation including a shift brake,
It detects that the manual shift range is set to the forward travel range, that the vehicle is in idling mode when it is virtually stopped, and that the vehicle travel brake is operating, and these three conditions are detected. When all the conditions are met, the engagement pressure of the forward clutch is set to a value lower than the value when the forward gear is achieved, and the shift brake is engaged. detecting that the braking operation of the vehicle running brake has been released and that the accelerator pedal has been depressed;
When the braking action of the vehicle travel braking brake is released, the engagement pressure of the forward clutch is increased to a value when a forward gear is achieved, and when the accelerator pedal is depressed, the shift brake is released. A control method during idling operation, characterized in that: 2. In the idle operation control method as set forth in claim 1, the low value of the engagement pressure of the forward clutch is a value that causes the forward clutch to slip. Control method during operation.