Honda Giken Kogyo Kabushiki Kaisha

Hideo Furukawa

Tatsuyuki Ohashi

Hiroshi Ishikawa

Norio Nakauchi

Masatoshi Shimizu

Yoichi Sato

Kazuma Hatakeyama

Satoru Sunada

Keiichi Ishikawa

Koichi Kimura

Hiroshi Yoshizawa

Noboru Kondo

Chihiro Matsubara

Hideo Fukushi

Yasuhiro Ijichi

Yutaka Ohyama

Takafumi Maruyama

A control system for an electronic device such as a solenoid for a vehicle transmission which is controlled by PWM. In the system, a difference (I.sub.H -I.sub.L) between the maximum value and the minimum value of current supplied to the solenoid is calculated and current supplied to the solenoid through a driver circuit is calculated based on the calculated difference and a predetermined coefficient as:

Pulse-width modulation control system for electronic device

A pulse-width modulation control system having a power source, driver circuits connected to the power source, and two solenoids, such as those for a vehicle automatic transmission, connected to the power source through the driver circuits, and pulse trains of a predetermined PWM duty ratio are supplied. The supplied currents are detected and A-D converted. In the system, one pulse train lags behind the other at the leading edge. When PWM controls two solenoids at the same time using an on-board microcomputer, two voltage memory circuits are additionally needed, since the microcomputer ordinarily has only one A-D converter. With the arrangement, only one voltage memory circuit is needed, rendering the system configuration simple.

Pulse-width modulation control system for multiple solenoids utilizing a

A vehicle automatic transmission control system which makes it possible to estimate an ATF temperature without using an expensive ATF temperature sensor. The estimation of the ATF temperature is configured such that based on the coolant temperature at engine starting, the temperature increase owing to heat inflow to the ATF per unit time and the temperature decrease owing to heat outflow from the ATF per unit time are calculated quantitatively and the sum of the calculated values is used to determine the estimated ATF temperature TATF. More specifically, when it is found that only a short time has passed between engine turnoff and restarting, the ATF temperature is estimated at engine restarting from the coolant temperature at engine turnoff, the estimated ATF temperature at engine turnoff and the coolant temperature at engine restarting. On the other hand, when the time between engine turnoff and restarting is found to be long, both the coolant and the ATF are assumed to be completely cooled and the ATF temperature is in principle defined as the coolant temperature at restarting.

Control system for hydraulically operated vehicle transmission

A vehicle automatic transmission control system in which the clutch is controlled in a slipping state if a torque converter is locked up when the gear shift command is not output. When the engine speed fluctuates, the fluctuations pass through the transmission and wheels and act on the ground to produce a reaction which passes back through the wheels and vehicle body and acts on the passengers as surging. In the prior art, this surging is prevented by slip-controlling the lockup clutch. This complicates the hydraulic control circuit. In the subject control, therefore, the clutch is slip-controlled even when no gearshift is in progress so as to absorb surging by slipping the clutch, not by the torque converter as in the prior art. As a result, it suffices to control the lockup clutch L of the torque converter between only two positions, one for complete lockup and one for complete release, rendering the structure of the hydraulic control circuit simple.

Control system for slipping at least one clutch instead of slipping a

A vehicle automatic transmission control system, in which when a gear to be shifted to is determined in response to the throttle opening and vehicle speed, hydraulic oil is supplied to a clutch for the gear to be shifted to. In an early period of the gearshift, the hydraulic oil is supplied to decrease a time lag between an output of the gearshift command and a start of clutch engagement. In the system, there is provided, instead of an expensive oil pressure sensor, a means for estimating or detecting the clutch oil pressure as a capacity of power which the clutch can transmit. When the estimated or detected pressure is high, the supply of oil to the clutch is prohibited so as to prevent sudden clutch engagement which would otherwise produce shock.

Hydraulic pressure control system for hydraulically operated vehicle

A vehicle automatic transmission control system having a torque converter having an input connected to an internal combustion engine mounted on the vehicle and an output connected to a gear system of the transmission, which makes it possible to estimate an ATF temperature without using an expensive ATF temperature sensor. The estimation of the ATF temperature is configured such that based on the coolant temperature at engine starting, it calculates the temperature increase owing to heat inflow to the ATF per unit time and the temperature decrease owing to heat outflow from the ATF per unit time quantitatively and uses the sum of the calculated values to determine the estimated ATF temperature TATF. The parameters used for calculating the temperature include the state of the torque converter, the type of gearshift, a vehicle speed (temperature increase owing to stirring of the ATF), the state of a heat exchanger, and the like.

Hydraulically operated vehicle transmission

A hydraulic control system for a hydraulically operated vehicle transmission. The system is configured to have a first gearshift mode for determining a gear ratio to be shifted to in accordance with a predetermined gearshift schedule based on detected parameters and a second gearshift mode for changing a gear ratio in accordance with at least one of an upshift command and a downshift command given by the driver. The first mode or the second mode is selected. And when the engine coolant temperature is found to be less than a predetermined value, the selection is prohibited or invalidated. This is because when the temperature is low, the viscosity of the ATF may be high and the time taken for completion of the gearshift is long, causing the driver to sense a time lag between the point at which the command was output and the point at which the actual gearshift is conducted. In the first mode, the driver does not sense this kind of time lag because the gearshift command is output by an electronic control unit without the driver knowing when it was output.

A hydraulic pressure control system for a frictional engagement element such as clutches for a vehicle automatic transmission. The engagement state of the clutches, i.e., the normality of clutch state or operation is discriminated by detecting the degree of clutch engagement (clutch slippage), specifically by calculating a ratio between the input rotational speed and the output rotational speed, and by comparing the calculated ratio with the gear ratio designated by the shift command at that time. When the clutch is found to be normal, the hydraulic pressures on the releasing and engaging clutches are controlled for temporarily bringing the total torque transferred by the two clutches below the transmission input torque, i.e., for reducing the co-engagement amount to the required minimum. On the other hand, when it is ascertained that the clutch is not normal, the hydraulic pressures of the two clutches are controlled in a conventional manner.

A control system of a vehicle automatic transmission in which an engine load and a vehicle speed are detected and used to determine a vehicle acceleration in accordance with the preestablished characteristics. An actual vehicle acceleration is at the same time calculated in response to the detected vehicle speed. The difference therebetween is then calculated and the calculated value is added to a difference calculated earlier to obtain an average therebetween. Five gear shifting scheduling maps, for example one for moderate hill climbing, one for level-road running, one for steep hill descent, are preestablished and in response to the average obtained, one of the maps is selected. A gear shifting is controlled based on the selected map. A driver's intention to decelerate is estimated and is compared with a reference value which increases with increasing said average indicative of the grade of hill that the vehicle is descending. As a result, downshifting will not occur until the driver's deceleration intention becomes great at steep hill descending.

Control system for vehicle automatic transmission

A control system of a vehicle automatic transmission in which an engine load and a vehicle speed are detected and used to determine a vehicle acceleration in accordance with the preestablished characteristics. An actual vehicle acceleration is at the same time calculated in response to the detected vehicle speed. The difference therebetween is then calculated and the calculated value is added to a difference calculated earlier to obtain an average therebetween. Five gear shifting scheduling maps, for example one for moderate hill climbing, one for level-road running, one for steep hill descent, are preestablished and in response to the average obtained, one of the maps is selected. A gear shifting is controlled based on the selected map. The actual vehicle acceleration is corrected by the altitude where the vehicle is traveling so as to compensate for the engine output decrease due to the charging efficiency drop.

A control apparatus for a hydraulically operated vehicular transmission has a plurality of transmission trains to be established by a selective operation of a plurality of hydraulic engaging elements. The apparatus has a selecting device for selecting a transmission train according to a running condition of a vehicle. The apparatus is provided with a detecting device for detecting a power transmission capability value of the hydraulic engaging elements, and a device for determining a transmission train to be established, based on a detected result of the detecting device and a selected result of the selecting device. The detecting device detects a hydraulic engaging element whose power transmission capability value is above a predetermined value and designates a transmission train that corresponds to the detected hydraulic engaging element. The device for determining the transmission train determines a transmission train to be established, based on the transmission train designated by the detecting device and the transmission train or trains selected by the selecting device.

Control apparatus for hydraulically operated vehicular transmission

An oil passage is provided in an axially central portion of a spool which is received within a valve housing and rotatively driven by a pulse motor, and oil passages passed diametrically through the spool and connected to the oil passage, so that a hydraulic pressure from an input port connected to a hydraulic pressure source is selectively supplied to the oil passages for selectively engaging and disengaging frictionally engaging elements of an automatic transmission. An axially acting load provided by the hydraulic pressure is received by a thrust bearing mounted at an end of the spool. The supply of oil from the axial portion of the spool enables no side force to be applied, thereby reducing the frictional force and to enhance the sealability between the valve housing and the spool.

Rotary valve for automatic transmission

A control system of a vehicle automatic transmission in which an engine load and a vehicle speed are detected and used to determine a vehicle acceleration in accordance with the pre-established characteristics. An actual vehicle acceleration is at the same time calculated in response to the detected vehicle speed. The difference therebetween is then calculated and the calculated value is added to a difference calculated earlier to obtain an average therebetween. Five gear shifting scheduling maps, for example, one for moderate hill climbing, one for level-road running, one for steep hill descent, are pre-established and in response to the average obtained, one of the maps is selected. A gear shifting is controlled based on the selected map. In a pre-determined condition, such as when the engine load changes abruptly, braking is in progress and so on, the map selection is suspended and the control is carried out using the map selected earlier.

In an automatic automotive transmission system having a torque converter and a gear transmission unit, the gear transmission unit is shifted from one speed stage to another normally according to current vehicle speed and engine load, but is upshifted from one speed stage to a subsequent speed stage according to a vehicle speed and a stored value of the engine load at the time of the preceding upshift so that a series of upshifts may be carried out at regular intervals, and the vehicle operator may accomplish a smooth acceleration of the vehicle substantially without any efforts even when the engine load wavers from the level at the time when the preceding upshift took place.

Device for controlling an automatic automotive transmission

A method for controlling an automatic transmission by carrying out speed changes in a vehicle in accordance with predetermined characteristics, said characteristics including engine load and vehicle speed, and said method comprising the step of carrying out a non-creeping control. The non-creeping control is carried out by stopping a power transmission to, or decreasing a transmitting torque to, an output side of the transmission when braking apparatus is operated under an idling operating condition in which the vehicle is substantially stopped. The non-creeping control is continued once the non-creeping control has been started even if thereafter the braking apparatus ceases to be operating.

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Wako, Japan

Hideo Furukawa