Ford Global Technolgoies, LLC

Ford Motor Company Limited

Pramod Kumar Jain

Bradley Dean Riedle

Howard Cecil Kuhn

Balaram G Sankpal

James Merner

Ronald James Vodicka

Gopichandra Surnilla

David Karl Bidner

Hong Jiang

Roger Lyle Huffmaster

Derek Kinch

Stanley L Pierce

Brian Michael O'Neil

Kendrick Morrison

Larry T Brown

Cory Benson LaRoche

Alexander Phillip McDonnell

Joseph Scott Slayton

Thomas T Tibbles

Ronald Thomas Cowan

John Randall Armstead

Chuanchi Tang

Steven Craig Meisner

Ronald T Cowan

Andrew Paredes

Armand Giannamore

A transmission includes a latch valve with latched and de-latched states. In the de-latched state, the latch valve directs a control pressure to a clutch apply circuit. In the latched state, which is entered in response to a control pressure higher than a latch pressure, the latch valve directs a line pressure to the clutch apply circuit. A controller manages the transition from latched to de-latched differently depending upon the transmission input torque and gear state. At high transmission input torque, the controller first reduces the control pressure to rapidly accelerate a spool in the latch valve, and then increases the control pressure to prevent clutch slip. At low torque, the controller reduced the pressure to an intermediate value during the transition and then reduces it again. At moderate torques, the controller reduces the pressure directly to a target pressure in a single step.

Control of transmission latch valve

An automatic transmission ratio shift control system and method for a powertrain having an engine and multiple-ratio gearing controlled by friction elements actuated by hydraulic pressure, an electronic controller for establishing torque transitions among the friction elements as the gear ratio changes, the engine speed being controlled by an electronic throttle control. The strategy employs an electronic throttle and closed loop engine speed control and uses fuel and air as an energy source to increase engine speed during a power-off downshift. The engine speed is boosted to a level close to the synchronous speed in conjunction with release of the off-going friction element. The on-coming friction element is then applied as the engine speed approaches a desired speed. The engine speed increase is timed to lead an increase in torque converter speed.

Coasting downshift control for automatic transmissions

An automatic transmission ratio shift control system and method for a powertrain having a throttle-controlled engine and multiple-ratio gearing, torque flow paths through the gearing being established and disestablished by pressure-operated friction elements, an electronic controller for establishing torque transitions between the friction elements as ratio changes occur in the multiple-ratio gearing, the engine throttle being controlled by an electronic throttle control that is decoupled from the driver-controlled accelerator pedal, the transmission torque output being controlled by means of a friction element capacity control strategy including a feed-forward torque term determined by changes in commanded torque, the slip duration during a ratio change being controlled by means of closed-loop engine torque control.

Automatic transmission shift control

Systems and methods for coordinating control of a DISI engine and automatic transmission determine the current and next engine operating modes and selectively modify or delay a requested transmission ratio change based on the current operating mode of the engine. Ratio changes requested during closed loop stoichiometric operation and during NOx purging cycles are commanded without delay while ratio changes requested during transitions between lean mode operation and stoichiometric operation may be delayed or the current operating mode extended to permit the ratio change to complete. Torque modulation may be provided during the ratio change using air, fuel, and/or spark control depending upon the engine operating mode.

Transmission ratio change control during mode transitions in lean burn/DISI engines

A control strategy and method for controlling application and release of friction elements in an automatic transmission to effect gear ratio changes as one friction element is release and another friction element is applied during ratio changes. The transmission has an electronic controller and multiple solenoid regulator valves hydraulically coupled directly to pressure-operated friction elements. Powertrain variables are obtained and processed to calculate gear ratio control parameters derived from desired line pressure for a pressure control valve circuit that communicates with the friction elements. The desired gear ratio is determined for each given set of powertrain variables. Upshifts and downshifts are obtained by releasing one friction element in synchronism with an application of the other friction element, whereby a direct friction element to friction element torque transition is achieved with minimal inertia torque disturbances.

Control strategy and method for independently controlling friction element actuators for an automatic transmission

An automatic control strategy for use with a multiple-ratio transmission in an automotive vehicle driveline in which the crankshaft of an internal combustion engine is connected directly to torque input elements of multiple-ratio gearing without an intervening hydrokinetic torque converter. The strategy is adapted especially for use with a wet auto clutch to provide forward or reverse drive engagement during vehicle launch and during transient damping of driveline disturbances. The strategy makes it possible to control the clutches to achieve maximum vehicle acceleration by controlling the engine speed so that it operates at maximum torque throughout the useful engine speed range for any given engine throttle position. The entry and exit conditions for each drive mode are determined by the strategy so that optimum drive-away performance and optimum shift control, as well as soft clutch engagement and full clutch engagement, can be achieved.

Control strategy for an automatic transmission

An adaptive electronic transmission control for an automatic transmission having multiple-ratio gearing establishing plural torque flow paths between a torque input member and a driven member, the relative motion of the elements of the gearing being controlled by a friction torque establishing member and an overrunning coupling connection between two gear elements of the gearing. A ratio shift is achieved by establishing a driving connection between a selected gearing element and a torque delivery shaft. The shift is achieved by controlling the capacity of the friction element using a fluid pressure actuator. Shift quality is optimized by establishing a bias pressure on a friction element accumulator and by using a feedback control system to control the rate of change of transmission ratio during the shift.

Adaptive electronic transmission control system and strategy for nonsynchronous automatic transmission

An adaptive control system and method for direct clutch engagement control for an automatic transmission including a micro-controller that receives and stores input data from driveline sensors and executes transmission clutch control logic. The micro-controller develops output signals in real time and transfers the signals to a driver circuit that controls solenoids that enable clutch engagement. The signals for establishing clutch pressure buildup are delivered to a driver circuit that produces hydraulic pressure at the clutch to achieve a smooth torque and speed transition for the torque input elements of the transmission. Adaptive pressure values are stored in a keep-alive memory. The pressure values are adjusted values based on the result of previous engagements. This compensates for driveline variables such as changes in coefficients of friction, spring loads, clutch wear, etc., whereby engagement cycle time is reduced and actual pressure buildup rate is maintained close to desired value to achieve a desired slip change rate, thereby achieving consistent, improved engagement quality.

Engagement control logic for an automatic transmission clutch with adaptive engagement feel

A continuously variable belt and sheave drive mechanism for use with an internal combustion engine in an automotive vehicle driveline including a simplified valve system that responds to control commands from a microprocessor that receives input data from engine, turbine and output shaft speed sensors, an engine throttle position sensor and a sheave position sensor as well as other driveline variables so that the operating characteristics of the transmission are matched to the speed torque characteristics of the engine to produce improved driveline efficiency and performance while permitting the engine speed to be related functionally to the throttle position as well as vehicle speed and permitting engine speed to increase when rapid acceleration is desired while minimizing changes in engine speed for small throttle position variations.

Continuously variable transmission

A method is provided for use in a vehicle including an automatic transmission having at least one load carrying friction element, such as clutch, of optimizing the line pressure in the transmission by slipping the weakest friction element by a small amount. The method includes the steps of decreasing the line pressure from a predetermined base pressure to allow for incipient slip across the weakest friction element and then increasing the line pressure to obtain a temporary pressure at which the weakest friction element is no longer slipping. The method also includes the step of further increasing the line pressure from the temporary pressure to obtain an operating line pressure. Preferably, the operating line pressure provides the weakest friction element with additional capacity for transmitting torque without slip for normal driving conditions, i.e. sensed vehicle throttle positions within a predetermined hysteresis band.

Line pressure optimization in an automatic transmission

A control for a hydrokinetic torque converter lockup clutch having a clutch plate that cooperates with a torque converter impeller shell to define a control pressure cavity wherein the clutch plate is subjected to the pressure in the torus circuit of the torque converter and wherein an electronically controlled valve system is used to modulate the pressure in the control pressure cavity thereby varying the clutch capacity to establish a controlled degree of slip of the clutch so that the actual slip of the clutch may be maintained at a target slip value which is adjusted depending upon the value of input shaft speed data and throttle position data stored in the memory of a microprocessor, the microprocessor being designed to calibrate a desired slip value for each engine torque and turbine speed condition whereby a closed-loop electronic control may be achieved to provide a partial converter bypass during the major portion of the vehicle operating time.

Electronic control system for controlling torque converter bypass

A control system for transferring torque from a first, offgoing clutch to a second, oncoming clutch while a gear shift is being made includes speed sensors for determining the speeds of the engine shaft and the output shaft of the transmission, a gear selector position indicator, a throttle position indicator and a gear ratio sensor. Solenoid operated valves open and close a source of high pressure fluid to the clutches, whose engagement and disengagement holds the gear elements of the transmission by means of which the various speed ratios are produced. An electronic computer is supplied with the digital equivalent of the shaft speeds, the position of the gear selector and of the throttle. The engine speed-output shaft speed ratio is used as a feedback signal on the basis of which an error between its value and a commanded value is determined. An equation for determining the duty cycle is repetitively calculated and its value converted to a pulse width modulated electrical current that is applied to the solenoid windings. The equation corrects a previously calculated duty cycle with the feedback error value.

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Farmington Hills, MI, United States of America

Pramod Kumar Jain