Caterpillar Inc.

Caterpillar Tractor Co.

Randall M Mitchell

Alan L Stahl

James R Talbott

Javad Hosseini

Todd D Creger

Ashok K Kajjam

Richard B League

Gregory L Williamson

Michael F Coffman

Daniel Craig Wood

Noel J Rytter

Tony L Marcott

Weldon L Phelps

Douglas A Carlson

David L Dickrell

Steven C Bray

James E Schimpf

Eric A Hutchison

Lowell E Johnson

Dwight S Holloway

John T Armstrong, Jr

Philip C McKenzie

Chris D Brandt

David W Bump, Deceased

David M Spurlock

In one aspect of this invention, a fluid actuated clutch is disclosed. The fluid actuated clutch is operatively connected to a control valve that is actuated by an electronic controller that receives a signal from an input mechanism, including a value for speed of an engine drive and a value of output speed for a torque converter. The method includes detecting a torque converter ratio which is the output speed of the torque converter divided by the engine drive speed, and detecting if there is at least one torque converter decrease exceeding a predetermined level and preferably detecting if there are at least two consecutive decreases in the torque converter ratio with at least one of the torque converter decreases exceeding a predetermined minimum level. This condition represents the end-of-fill point for the fluid actuated clutch.

End-of-fill detector for a fluid actuated clutch

A control system and method is provided for changing the shiftpoints of a transmission for part throttle shifting. A input section delivers a actual gear signal, a engine speed signal and a torque converter output speed signal A controller receives the input signals and varies the transmission shiftpoints relative to the received signals. The controller also delivers signals to the transmission to upshift, downshift or that no shift is necessary.

Control system for an automatic transmission having shift points based

A diagnostic system is provided for detecting a fault condition in a transmission having a plurality of rotating components, a plurality of clutches, and a transmission control. The diagnostic system includes speed sensors producing speed and direction signals representative of the rotational velocity of the rotating components, a processor for calculating the relative rotational speed between two or more clutches and for indicating a fault condition in response to the relative rotational speed and a period of time.

Transmission control fault detection

The present invention is directed toward determining when a clutch of an automatic transmission substantially fills with fluid. Once it is accurately determined when a clutch fills with fluid, then control over the transmission shifting may reliably be performed. The present invention determines when an on-coming speed clutch substantially fills with fluid in response to determining when an off-going speed clutch releases. Further, the present invention determines when an on-coming direction clutch substantially fills with fluid in response to determining when the torque converter output torque suddenly changes.

Method for determining the fill time of a transmission clutch

The present invention relates to an adaptive control method for an automatic transmission. The method includes the steps of:

Adaptive control method for an automatic transmission

In one aspect of the present invention, a method for controlling an interrupted shift for a powershift transmission is disclosed. The method first determines which clutches are active and then classifies each of the active clutches. Thereafter, the method calculates the timing associated with the engagement and disengagement of the classified active clutches to result in a smooth transition to the final selected gear.

Method of controlling interrupted shifts for a powershift transmission

A diagnostic system is provided for responding to a fault condition in a transmission having an electronic control including diagnostics for both electrical and mechanical failures, said diagnostics indicating the affected clutch and the type of failure. The diagnostic system includes a processor for selecting a first table of available gears in response to the affected clutch and a first subset of electrical and mechanical failure types being diagnosed and for selecting a second table of available gears in response to the affected clutch and a second subset of electrical and mechanical failure types being diagnosed.

Transmission control default operation

In one aspect of the present invention, an electronic shift control for a powershift transmission is disclosed. The transmission includes a plurality of speed and direction changing clutches. A plurality of pressure control valves are individually connected to the clutches. A hydraulic pump delivers pressurized hydraulic oil to predetermined pressure control valves to meter hydraulic fluid in response to receiving a clutch command signal. The method produces a shift from a first transmission ratio to a second transmission ratio through disengagement of an off-going clutch associated with the first transmission ratio and engagement of an on-coming clutch associated the second transmission ratio. The method includes filing an on-coming speed clutch, releasing an off-going direction clutch in response to the on-coming speed clutch being filled, and thereafter, gradually increasing the on-coming speed clutch pressure to engage the speed clutch. Finally, the on-coming direction clutch pressure is gradually increased to engage the direction clutch in response to the on-coming speed clutch being engaged.

Method of controlling clutch-to-clutch shifts for a powershift

An electrohydraulic control device for a drive train of a vehicle including an engine, a transmission, a source of pressurized fluid, and an input clutch driving connected between the engine and the transmission. The device includes a control lever or handle having a control member progressively manually movable between first and second positions, wherein the transmission is adapted to responsibly shift between a FORWARD and a REVERSE gear ratio in response to movement of the control member from the first position to the second position. An electronic control module is adapted to determine a transmission clutch relative speed as a function of the transmission output speed and the transmission input speed and responsively engage and disengage the input clutch during a directional shift.

Electrohydraulic control device for a drive train of a vehicle

An apparatus is provided for use in a vehicle having an engine driven transmission which includes a plurality of gear ratios. The apparatus includes a sensor adapted to sense a parameter indicative of vehicle speed and responsively produce a vehicle speed signal. A downshift switch is provided to controllably produce a downshift signal. An engine speed sensor senses engine speed and responsively produces an engine speed signal. A controller is adapted to receive the vehicle speed, engine speed, and downshift signals, process the vehicle speed signal to produce a transmission control signal, produce a down shift enable value as a function of the engine speed signal, and modify the transmission control signal to correspond to a lower gear ratio in all but the lowest gear ratio when the downshift signal is received and a value responsive to the vehicle speed signal is less than the down shift enable value signal. An actuator is adapted to receive the transmission control signal and responsively control the transmission gear ratio.

Method and apparatus for controlling manual downshifting in an automatic

Vehicles having implements are typically used to perform repetitive functions in work cycles. An implement control system raises and lowers an implement relative to the vehicle and reduces the stresses applied to the vehicle from abruptly stopping the motion of the implement. A lever pilot signal is produced in response to the pivotal position of a control lever. An electrohydraulic pilot signal is also produced. The pilot signal having the greater pressure is directed to a main valve for controlling the position of the implement. The method and apparatus of the instant invention are applicable to a number of vehicles having a hydraulically operated implement.

Method and apparatus for controlling an implement

A vehicle such as an earthmoving wheel loader has an engine, a torque converter having an impeller element, a reactor element and a turbine element, and an input clutch connected between the engine and the impeller element. An electrohydraulic control device is provided to controllably engage the input clutch and that includes a microprocessor-based electronic control module, an actuator mechanism having a control member that is progressively movable between first, second and third positions to deliver a first electrical signal to the electronic control module, and a valve for directing fluid to the input clutch at a decreasing pressure level when the control member is moved from the first to the second positions in response to another signal from the electronic control module. The electronic control module is programmed to maintain at least a minimal pressure level to the actuating piston of the input clutch when the control member is between the second and third positions. Moreover, a service brake is increasingly engaged by a service brake mechanism in response to the control member moving between the second and third positions. Other logic functions are included to control the input clutch and a lockup clutch connected between the engine and the turbine element.

An apparatus for regulating the speed of internal combustion engine of a hydrostatic system. A fuel control means acts to control the quantity of fuel delivered to the engine responsive to the immediate hydraulic flow demanded by operation of the hydrostatic system. The speed of the engine is set to one of a plurality of discrete levels in response to the required flow being within one of a corresponding plurality of preselected ranges.

Hydrostatic vehicle control

An apparatus for controlling both pump displacement of a variable displacement hydraulic pump and the quantity of fuel delivered to an internal combustion engine for the purpose of delivering a requested hydraulic flow at a highly efficient operating point. The apparatus includes an underspeed control means for reducing pump displacement in response to the operating speed of the engine lugging below a desired operating speed. Additionally, a fuel control means operates to reduce the quantity of fuel delivered to the engine in response to the operating speed of the engine rising above the desired operating speed.

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Washington, IL, United States of America

Randall M Mitchell