Honda Giken Kogyo Kabushiki Kaisha

Masamitsu Fukuchi

Yoshiharu Saito

Yasushi Inagawa

Takanori Kon

Shinya Majikina

Kazutomo Sawamura

Satoru Sunada

Yoshikazu Nemoto

Masahide Saito

Shirou Godai

Masakazu Shiraishi

Hitoshi Kondou

Satoshi Kato

A system for controlling an automatic transmission of a vehicle, wherein the initial value of the desired pressure to be supplied to a hydraulic clutch for the current gear now being engaged is determined appropriately, when conducting a power-on downshifting, so as to decrease the shift shock experienced by the vehicle occupant effectively, irrespectively of the change in the throttle opening, while ensuring to reduce the volume of the mapped data.

Control system for automatic vehicle transmissions

A system for controlling an automatic transmission of a vehicle, wherein if the change of the destined gear GB (i.e., the target gear SH) is required when the jumping shift, i.e., two-gear downshifting is in progress, the input/output rotational speed ratio GRATIO (indicative of degree of shift progress) is compared with the predetermined input/output rotational speed ratio &num;GRCN312 or &num;GRCN423, and based on the result of comparison, how the shift to establish or effect the required destined gear GB, i.e., the shift mode QATNUM is determined, thereby enabling to improve or enhance the response to the change of the destined gear GB during two-gear downshifting. It can also prevent the clutch from being degraded in such a shifting.

A system for controlling an automatic transmission of a vehicle, in which a pressure supply time to complete removal of the clutch-stroke play is determined based on the input shaft rotational speed. And a residual oil amount in the clutch is estimated and the time is corrected by the residual oil amount. The preparatory pressure to be supplied within the time is also determined based on the input shaft rotational speed and the ATF temperature. With this, it becomes possible to effect the clutch-stroke play removal within a less variant time and with a good response, thereby decreasing the shift shock effectively so as to improve the feeling of the vehicle occupant.

A system for controlling an automatic transmission of a vehicle, wherein a pressure to be supplied to the hydraulic clutch of a target gear is determined based on a desired value of acceleration of gravity acting in the longitudinal direction of the vehicle and other parameters including an engine torque, thereby decreasing the shift shock effectively, while ensuring to finish the shift within an expected period of time. Moreover, the engine torque is estimated using a parameter indicative of inertia torque used for raising the engine speed. With this, it becomes possible to determine the engine torque inputted to the transmission, thereby decreasing the shift shock more effectively.

When a contradictory event in which raising of the engine rotation speed is detected and the inertia phase start time is early occurs ( ), a learn correction is made to engagement hydraulic pressure (ON side). If the raising of the engine rotation speed cannot be canceled still after the learn correction is made, release hydraulic pressure (OFF side) is increased for correction.

Shift control apparatus of automatic transmission for vehicle

A system for controlling an automatic transmission of a vehicle, wherein the hydraulic pressure to be supplied to the frictional engaging element such as a hydraulic clutch is determined, taking the performance of tracking or follow-up of the hydraulic pressure into account so as to enhance the control toughness against the engine speed change, thereby decreasing the shift shock effectively so as to improve the feeling of the vehicle occupant, while ensuring to prevent the engine from revving over or excessively. Further, the friction coefficient of the hydraulic clutch is calculated additionally taking parameters including the rotational difference thereof into account to determine the pressure to be supplied to the frictional engaging element, thereby further decreasing the shift shock effectively.

A down-shift control system is provided, by which if sufficient torque cannot be obtained for an acceleration request or intention at a shift position, a down-shift operation is suitably performed so as to realize a reliable driving capability and no shift-busy phenomenon occurs. The system includes a section for calculating target driving force of a vehicle according to a degree of opening of an accelerator pedal and a speed of the vehicle; a section for detecting the present shift position of the vehicle; a section for calculating target engine torque based on the target driving force and the present shift position; a section for comparing the target engine torque with a set value determined according to torque characteristics of the engine; a section for performing an accumulating operation relating to the degree of opening if it is judged that the target engine torque equals or exceeds the set value; and a section for outputting a down-shift command if the accumulated value exceeds a threshold relating to the degree of opening.

Down-shift control system based on driver's intention for acceleration

A throttle controller having a throttle control section is provided so as to eliminate any inconsistency in the degree of opening of the throttle at the time of mode switching, and to obtain a superior driving efficiency. In the driving mode, the throttle control section calculates the degree of opening of the throttle for generating a target driving force calculated based on a plurality of parameters including the degree of depression of the accelerator, and performs a driving-force control. In the manual mode, the throttle control section performs a control for driving the engine using a degree of opening of the throttle which one-to-one-corresponds to the degree of depression of the accelerator. When the mode is switched between the driving and manual modes, the throttle control section performs switching between the two control modes if the degree of depression of the accelerator is minimum or maximum.

Throttle controller keeping consistent degree of opening of throttle at

A lock-up control device controls an engaging force of a lock-up clutch, which shares engine output with a torque converter to transmit it toward an input shaft of a transmission of a car. First, target driving force is produced based on accelerator pedal opening and car velocity. Then, required torque is produced based on a gear ratio and the target driving force. Target engine speed is produced based on the required torque, wherein the target engine speed is set to avoid occurrence of abnormal sounds and abnormal vibrations. Thus, the lock-up clutch is controlled in such a way that real engine speed does not become less than the target engine speed in case of a gear change corresponding to a shift-up operation, for example. Basically, the lock-up clutch is controlled to have engaging force, which is made as maximal as possible to improve fuel efficiency. In other words, the lock-up clutch is controlled to be as tightly as possible. Or, the lock-up clutch which is initially set at a tight state is turned off just after the gear change start timing if it is predicted that the real engine speed after the gear change will become lower than the target engine speed.

Lock-up control device

A lock-up control device is provided to control engaging force of a lock-up clutch, which shares engine output with a torque converter to transmit it toward an input shaft of a transmission. Herein, input shaft torque is estimated based on engine speed and engine intake negative pressure, while engine torque is estimated based on engine speed and throttle opening. A weight coefficient is produced based on an amount of variations of the engine torque when the amount of variations is greater than a prescribed value. Then, weighted mean engine torque is calculated by the input shaft torque and engine torque in accordance with the weight coefficient. Thus, the lock-up control device controls the lock-up clutch based on the weighted mean engine torque in such a way that the engaging force of the lock-up clutch is increased in response to the rise timing of the weighted mean engine torque. For example, the weight coefficient is determined in such a way that the engine torque is given high distributed weight in the weighted mean engine torque as compared with the input shaft torque. Thus, it is possible to increase the engaging force of the lock-up clutch promptly in response to the rise mode of the real engine torque, by which it is possible to avoid occurrence of control delay in control of the lock-up clutch.

In order to improve the fuel consumption by maintaining the lock-up clutch as tightly as possible during the down-shift operation, a lock-up clutch control apparatus is provided. The lock-up clutch control apparatus comprises a revolution control device for predicting the number of revolutions of the an input axis of transmission and the number of revolutions of an engine after the speed change before a down-shift operation; a torque converter judgement device for judging the state of the torque converter in terms of whether or not a torque ratio of the torque converter will be in the torque amplification range when the lock-up clutch is turned off, from the number of revolution of the input axis of the transmission and the engine speed obtained by the revolution prediction device; and a control device for turning off the lock-up clutch, if the lock-up clutch before the speed change is in a tight condition, in the case when the judgement device judges that the torque converter will be in the torque amplification range when the lock-up clutch is turned off.

Lock-up clutch control apparatus

A hydraulic pressure system for a frictional engaging element such as clutches for a vehicle automatic transmission. The engagement state of the clutches is detected from the clutch slip rate, and the desired change rate of the rotational speed of the transmission input shaft (the main shaft rotational speed) during the gearshift operation period is varied based thereon. The hydraulic pressures supplied to the clutches are controlled for bringing the actual rotational speed change rate to the desired value. Since the clutch engagement state can therefore be controlled based on the desired value, irrespective of the temperature of the oil (ATF) and aging of the clutches, it is at all times possible to secure optimum gearshift characteristics and to avoid the occurrence of gearshift shock.

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Wako, Japan

Masamitsu Fukuchi