Honda Giken Kogyo Kabushiki Kaisha

Honda Motor Co., Ltd.

Akihira Aoki

Shuichi Fujimoto

Hiroshi Saotome

Takahiro Eguchi

Takeshi Kurata

Hisashi Kunii

Keiichi Hanyu

Keiji Tojo

Yukihiko Fukushima

Isao Tabushi

Genso Igari

In a control apparatus for a vehicle power transmission mechanism (automatic transmission) having a transmission equipped with at least an input shaft connected to a drive source mounted on a vehicle, an output shaft connected to the input shaft via a speed ratio change mechanism, and a clutch (start clutch) which transmits a rotation of the output shaft to driven wheels and whose engaging force is regulated, a clutch output rotation change rate is calculated, and the clutch engaging force is corrected to decrease when the calculated output rotation change rate is a positive value, and the clutch engaging force is corrected to increase when the calculated output rotation change rate is a negative value, thereby enabling to suppress clutch juddering occurred due to a difference between input and output rotational speeds of the clutch.

Control apparatus for vehicle power transmission mechanism

A control apparatus for a continuously variable transmission is capable of continuously changing an output of an internal combustion engine mounted on a vehicle and allowing a transmission mode to be switchable between a continuous transmission mode in which a transmission ratio is set continuously and a stepped transmission mode in which the transmission ratio is set stepwise. A transmission mode selector is configured to change the transmission mode in such a manner that in a case where the stepped transmission mode is selected, when a engine rotation speed reaches a first predetermined rotation speed, then falls below a second predetermined rotation speed which is lower than the first predetermined rotation speed, and further falls below a third predetermined rotation speed, the transmission mode is switched from the stepped transmission mode to the continuous transmission mode.

Control apparatus for continuously variable transmission

In a hydraulic apparatus for an automatic transmission having a torque converter with a lockup clutch and CVT, there are provided a first control valve for controlling hydraulic pressure supply to the lockup clutch oil chamber, a first electromagnetic solenoid valve for controlling operation of the first control valve, a second control valve for controlling hydraulic pressure supply to the CVT pulleys, a second electromagnetic solenoid valve for controlling operation of the second control valve, a switching valve interposed between the oil chamber and the first control valve. In the apparatus, when detecting that the first control valve or first electromagnetic solenoid valve is failed and the lockup clutch is locked in engaged condition, current supply to the second electromagnetic solenoid valve is stopped so that it operates the switching valve to disengage the lockup clutch, thereby enabling to forcibly release the engagement without manipulation by the operator.

Hydraulic apparatus for automatic transmission

A control apparatus for a continuously variable transmission of a vehicle is provided for switching the transmission from a continuously variable transmission mode to a stepped transmission mode without giving any discomfort to the driver, and for appropriately responding to a request for acceleration from the operator during the stepped transmission mode. The control apparatus comprises an ECU for setting a target transmission ratio in accordance with the detected operating condition of the vehicle, controlling the transmission ratio of the continuously variable transmission to reach the set target transmission ratio, and switching the transmission mode between a CVT mode and an AT mode. When the transmission mode is switched from the CVT mode to the AT mode, the ECU sets the target transmission ratio to a transmission ratio in the CVT mode immediately before the switching. Subsequently, when the engine rotational speed reaches an upper limit rotational speed, the ECU sets the target transmission ratio to a transmission ratio on a high speed side such that the engine rotational speed falls to an up-shift rotational speed.

Control apparatus for continuously variable transmission of vehicle

A control apparatus for a continuously variable transmission for use with a vehicle is provided for permitting a driver to select one from three transmission modes for the continuously variable transmission, and providing an appropriate transmission ratio in accordance with a particular operating condition of a vehicle without causing an insufficient engine torque or over-revolution, particularly when the transmission is switched from a continuously variable transmission mode to a stepped manual transmission mode. The control apparatus comprises an ECU and an MT switch. The ECU executes a continuous automatic transmission mode for continuously setting a transmission ratio of the continuously variable transmission in accordance with a detected operating condition of the vehicle. The ECU also executes a stepped automatic transmission mode for setting the transmission ratio of the continuously variable transmission to one of a plurality of predetermined transmission stages in accordance with the detected operating condition of the vehicle. The CPU further executes a stepped manual transmission mode for setting the transmission ratio to one of a plurality of predetermined transmission stages in accordance with a driver's intention of transmission. The ECU sets the continuously variable transmission to one of the continuous automatic transmission mode, the stepped automatic transmission mode and the stepped manual transmission mode in accordance with a manipulating state of an MT switch.

An automatic transmission comprises a metal V-belt mechanism , which changes the speed ratio of the rotational output from an engine ENG, a forward/reverse direction change mechanism , which switches the rotational direction of the ratio-change mechanism, and a forward clutch , which actuates the switching operation of the rotational direction performed by the forward/reverse direction-change mechanism. A control system for this transmission comprises a regulator valve , which generates a line pressure, a manual valve , which is operated in correspondence to the shift lever and switches the supply of the line pressure to the forward clutch, and a drive-range sensor , which detects the operation of the manual valve. When the movement of the manual valve to a position where the line pressure is to be supplied to the forward clutch is detected by the drive-range sensor , the line pressure, which is adjusted by the regulator valve, is lowered for a predetermined time period.

Automatic transmission control system

In an apparatus for controlling a pulley side-pressure of a belt type continuously variable transmission mechanism provided, in series with a starting clutch, in a transmission of a vehicle having a function of stopping engine idling so that an engine is automatically stopped, if the vehicle start-up is controlled from the state of engine stopping in an ordinary way in which the pulley side-pressure is determined by that belt transmission torque corresponding to an output torque of the engine which is obtained by the rotational speed and the negative suction pressure of the engine, the pulley side-pressure becomes excessive by wrong judgement that the engine output torque is large, because the negative suction pressure is small at the beginning of the engine starting. The durability then deteriorates and the specific fuel consumption becomes poor. As a solution, at a vehicle start-up from the state of engine stopping, a belt transmission torque corresponding to that transmission torque of the starting clutch which is obtained by the engaging force of the starting clutch is compared with a belt transmission torque corresponding to the engine output. The pulley side-pressure is each controlled based on that transmission torque of the drive pulley corresponding to the smaller belt transmission torque and on the transmission torque of the driven pulley.

Apparatus for controlling pulley side-pressure of continuously variable transmission in vehicle having function of stopping engine idling

An electronic control unit ECU controls a shift thrust Ft applied to a variable width drive pulley through a control valve CV and makes the rotational speed Ne of the engine follow a target engine rotational speed Neo to vary the speed change ratio of a continuously variable transmission CVT. In this control, the shift thrust Ft is achieved as sum of a proportional term P and an integral term I, where the proportional term P is determined on the basis of the deviation DNe of the engine rotational speed Ne from the target engine rotational speed Neo, and the integral term I is determined as cumulative sum of the deviation. When the throttle of the engine is closed, the integral term is set larger than when the throttle is open.

Vehicular transmission control system

After the engine rotational speed Ne has become below a reference rotaional speed Neo, which is lower than an idling rotational speed of the engine, and after the pressure PL of oil passages and has begun to decrease, for a predetermined time, the currents supplied to electromagnetic valves and are adjusted to generate, in each electromagnetic valve, a second biasing force electromagnetically in a magnitude that can supplement a decrease in a third biasing force which is generated by the back pressure led through an oil passage and , respectively, and which decreases as the pressure of the oil passages and decreases. After the above metioned predetermined time has elapsed, the currents supplied to the eletromagnetic valves and are set almost to zero.

Drive and driven pulley necessary axial thrusts (Qdrnec, Qdnnec) necessary for power transmission without belt slippage are found in accordance with the input torque and transmission ratio; the vehicle speed and degree of accelerator opening target transmission ratio (itgt) and target rate of change of transmission ratio (ditgt) are found; this axial thrust (Qdnnec) is set as the driven pulley target axial thrust (Qdncmd); and the drive pulley axial thrust necessary to obtain the target values (itgt) and (ditgt) is set as the drive pulley target axial thrust (Qdrcmd). Then, if (Qdrcmd)&lt;(Qdrnec), this axial thrust (Qdrnec) is altered and set as the drive pulley target axial thrust (Qdrcmd) and the driven axial thrust necessary for obtaining the target values (itgt), (ditgt) is altered and set as the driven pulley target axial thrust (Qdncmd). Drive and driven pulley axial thrust control is performed such that these target axial thrusts (Qdrcmd, Qdncmd) are obtained.

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Wako, Japan

Akihira Aoki