Honda Giken Kogyo Kabushiki Kaisha

Honda Motor Co., Ltd.

Takanori Kon

Yoshiharu Saito

Yasushi Inagawa

Masamitsu Fukuchi

Shinya Majikina

Kazutomo Sawamura

Masashi Eto

Yoshikazu Nemoto

Shirou Godai

Masakazu Shiraishi

Junpei Hatsuda

Shigeki Kazehare

Hitoshi Kondou

A hybrid electric vehicle including a gradient acquiring portion which acquires a gradient of a road surface on which the vehicle is running, and a control portion which determines whether the vehicle runs on a first driving by means of power from the motor by releasing the engagement and disengagement portion, or on a second driving by means of power from at least the internal combustion engine by applying the engagement and disengagement portion. The control portion restricts a switch from the second driving to the first driving when the gradient of the downward slope is equal to or greater than a threshold value. The control portion holds the second driving when the switch from the second driving to the first driving is restricted, even though the control portion obtains a request for a switch to the first driving while the vehicle runs the downward slope on the second driving.

Hybrid electric vehiclecapable of switching driving modes based on gradient

A shift control apparatus comprises clutches driven by shift solenoids and whether or not the raising of the rotation speed occurs in an internal combustion engine is determined. If the raising of the engine rotation speed is detected, a hydraulic pressure learn correction is made to engagement hydraulic pressure and a time learn correction is made to the hydraulic pressure supply preparation time. The correction ratio of the energization-hydraulic pressure characteristic (I-P characteristic) of clutch clearance and the shift solenoid is set so as to become an appropriate distribution ratio and the learning is started based thereon.

Shift control apparatus of automatic transmission for vehicle

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, 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.

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 lock-up control device is provided to control the engaging and release of a lock-up clutch, which is arranged in parallel with a torque converter to transmit driving force of an engine of a car. Herein, target driving force is calculated based on accelerator pedal opening and car velocity. A present shift position is detected using a shift map based on accelerator pedal opening, car velocity and engine speed. Target engine torque is calculated based on the target driving force and present shift position as well as a torque amplification ratio, which is detected when the torque converter is placed in a torque amplification state. A lock-up release instruction is issued under conditions that the torque converter is placed in the torque amplification state while the target engine torque is greater than a preset value, which is determined in advance based on a torque characteristic of the engine. In addition, under the condition that the engaging of the lock-up clutch is released, the device makes a decision as to whether a shift-down operation is performed or not. Herein, accumulation is performed on the accelerator pedal opening under the condition that the target engine torque is greater than the preset value. So, a shift-down instruction is issued under the condition that an accumulated value of the accelerator pedal opening exceeds a threshold value in accumulation of the accelerator pedal opening.

Lock-up control device

A drive control device is provided for a vehicle which has an automatic transmission and which is capable of setting a throttle opening independently of an accelerator opening. Herein, the drive control device detects a shift range and an engine speed, based on which prescribed controls are made with regard to a throttle and a clutch. That is, if the engine speed is higher than a predetermined engine speed value when the shift range is changed over from a non-running range (e.g., N range) to a running range (e.g., D range), the drive control device controls the throttle opening substantially in a fully closed state while controlling clutch oil pressure of a start-mode-engaged gear to be set at a predetermined oil pressure value which is greater than zero and at which the clutch does not have a torque transmission capacity. In addition, in a predetermined time after the engine speed becomes lower than the predetermined engine speed value, the drive control device maintains the throttle opening in the fully closed state while gradually increasing the clutch oil pressure of the start-mode-engaged gear so as to control the clutch to start an engagement operation. Thus, it is possible to ease an engagement shock of the clutch which occurs when the driver changes gears from the N range to the D range while depressing the accelerator pedal.

Drive control device for vehicle

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 is provided so as to reduce a load imposed on the drive and transmission system in the stall state in which both the accelerator and brake are depressed. The controller comprises a throttle control section for calculating a degree of opening of the throttle for generating a driving force in accordance with the actual degree of depression of the accelerator used as a target degree of opening of the throttle so as to drive the vehicle by a target driving force calculated based on the actual degree of depression of the accelerator; a section for determining the stall state in which the gear lever is in a driving gear; the actual degree of depression of the accelerator is larger than a predetermined degree; the brake is operated; and the speed is smaller than a predetermined speed; and a storage section for storing a predetermined degree of opening of the throttle which is read out when the actual degree of depression of the accelerator is larger than the predetermined degree, and wherein the throttle control section limits the target degree of opening of the throttle to the predetermined degree stored in the storage section when the stall state of the vehicle is determined.

Throttle controller for limiting degree of opening of throttle in stall

The lock-up clutch control apparatus is provided with reference values for operating variations of the accelerator pedal predetermined for respective gear positions. The lock-up clutch control apparatus comprises a tightening permission judgement device 25 for judging whether it is appropriate to permit or prohibit tightening of the lock-up clutch, based on comparison between a reference value and an operating variation at present car conditions. Thereby, the lock-up clutch control apparatus is capable of reflecting the driver's intention to accelerate or reduce the car speed and is capable of enhancing drivability as well.

Lock-up clutch control apparatus

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.

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.

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Wako, Japan

Takanori Kon