Caterpillar Inc.

Caterpillar Tractor Co.

Caterpiller Inc.

Alan L Stahl

Randall M Mitchell

Javad Hosseini

Vernon Richard Smith

Ashok K Kajjam

Weldon L Phelps

James R Talbott

Kendall R Harrell

Todd D Creger

John F Szentes

Giles Kent Sorrells

Douglas A Carlson

Gregory H Gipp

Steven W Judy

Craig L Sells

William G Schwader

Donald E Foley

Danish A Hussain

James A Smittkamp

The present invention discloses a system and a method for controlling the timing of the filling of a fluid actuate. The system includes, a fluid actuated clutch an electronic controller adapted to detect an end-of-fill point for the fluid actuated clutch compare the end-of-fill point with a desired end-of-fill point and adjust at least one of a plurality of clutch fill parameters in response to the comparison in order to control the timing of the filling of the clutch and a control valve that is activated by the electronic controller.

Apparatus and method for controlling the end of fill of a fluid actuated clutch

A drive line assembly for a work machine is disclosed. The drive line assembly includes an engine driving an engine output shaft and an engine speed sensor which generates engine speed signals indicative of a speed of the engine output shaft. The drive line assembly further includes a torque converter driven by the output shaft which drives a transmission input shaft and a transmission speed sensor which generates transmission speed signals indicative of a speed of the transmission input shaft. The drive line assembly yet further includes a transmission driven by the transmission input shaft and having a first speed clutch, a second speed clutch, and a directional clutch, and a controller. The controller is operable to determine a torque converter ratio from the engine speed signal and the transmission speed signal and determine an engine load based on the torque converter ratio. The controller is further operable to control engagement of the first speed clutch, the second speed clutch and the directional clutch based on the engine load. A method controlling a drive line assembly is also disclosed.

Method and apparatus

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

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 activated by an electronic controller that receives a signal from an input mechanism. The system and method includes detecting an instantaneous clutch slip and detecting when the instantaneous clutch slip is less than an average of a predetermined number of cycles of instantaneous clutch slip that is divided by a predetermined factor. This condition represents the end-of-fill point for the fluid actuated clutch.

End of fill detector for a fluid actuated clutch

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

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

Vehicle diagnostic control system

A method is provided for executing a subroutine in a computer which includes a memory and a stack. The memory has a plurality of sequentially ordered memory address locations referenced by respective address codes. The subroutine is stored in a preselected range of memory locations. The method includes storing a signature word on the stack, the signature word corresponding to an entry address code in memory for the subroutine; storing a return address on the stack, the return address code corresponding to a memory location where control is to be passed after execution of the subroutine; passing control to the subroutine entry address; executing the subroutine; comparing the signature word stored on the stack with the subroutine entry address code; passing control to the return address if the compared values are equal; and executing a software interrupt if the compared values are not equal.

Method for executing subroutine calls

A drive system for a work vehicle is provided which includes first and second hydrostatic transmissions which are responsive to respective control signals for driving first and second ground engaging devices at a rate responsive thereto. A sensor is provided sensing the position of a manually operable control element and responsively producing a desired speed signal. A memory device is adapted to store data relates the desired speed signal to the first and second control signals in a preselected manner. A processor is provided for receiving the desired speed signal, responsively retrieving at least a portion of the data from the memory device, and producing the first and second control signals in response to the retrieved data and the desired speed signal. An adjusting device is provided for receiving at least one of the control signals, permitting controllable adjustment of the control signal so as to vary the speed of a respective ground engaging device. An overwriting device is provided for receiving the adjusted control signal and overwriting a portion of the stored data in response to the adjusted control signal.

Apparatus for calibrating the speed of hydrostatically driven traction

The subject invention provides an apparatus for controllably programming an EEPROM, thereby reducing the likelihood of an inadvertent EEPROM write. The apparatus includes a first circuit which repeatedly produces a pseudo address signal at a preselected frequency. A second circuit receives the pseudo address signal and deliveries a write-enable signal to the EEPROM in response to receiving the pseudo address signal a preselected number of times. A third circuit delivers an address signal and a corresponding data signal to the EEPROM during at least a portion of the production of the write-enable signal. The address signal is indicative of an address location in said EEPROM and the data signal corresponds to the data to be stored in the EEPROM address location.

Write protection method and apparatus for an EEPROM

Anti-spin control systems are useful, for example, in industrial off-road vehicles. It is desirable that such systems exhibit rapid response to adverse working conditions, and be capable of quickly applying braking forces to whichever driven wheel is rotating at a higher velocity at a given time. The instant invention includes an electrical circuit for producing first and second brake control signals having values responsive to a working condition wherein one of the vehicle wheels loses traction and rotates more rapidly than the other vehicle wheel. A first controllable valve receives the first brake control signal and responsively controllably engages a brake mechanism associated with the faster rotating wheel, while a second controllable valve receives the second brake control signal and responsively controllably moves a brake mechanism associated with the slower rotating wheel from a brake released position to a brake pre-engaged position. Therefore, upon detecting a slippery working condition, each of the brake mechanisms associated with the driven wheels of the vehicle is brought into a state of readiness for immediate braking effort with minimal time delay.

Anti-spin control apparatus and method

An apparatus determines the payload carried in a work vehicle by periodically measuring the pressure of a fluid contained within front and rear suspension struts. The struts are connected in supporting relation between a load carrying portion and a ground engaging portion of the vehicle such that a pressure differential between a loaded and unloaded vehicle can be shown to be indicative of the magnitude of the payload. Moreover, the pressures are a function of the geometry of a suspension means which interconnects the load carrying portion and the ground engaging portion.

Payload monitor

Anti-wheel spin control systems are useful, for example, in industrial off-road vehicles. It is desirable that such systems operate automatically and not be unduly influenced by false slip signals caused by steering of the vehicle. It is further desirable that the operability of the control be readily determined by the operator. The instant anti-spin control includes an apparatus for producing a slip signal having a value responsive to the difference in rotational velocity between the vehicle wheels, and for producing a test signal. A processor receives the slip signal and test signal, compares the slip signal value with a first predetermined reference value in response to receiving the slip signal in the absence of the test signal, and compares the slip signal value with a second predetermined reference value in response to receiving both the slip signal and the test signal. A brake control signal is produced in response to the slip signal value exceeding the compared reference value, and the braking mechanism corresponding to the slipping wheel is activated. In a second embodiment of the invention, a steer signal is also produced and applied to the processor. The steer signal is utilized to negate the effect of steering the vehicle on the produced slip signal. Thus, the disclosed anti-spin system accounts for false slip indications produced by steering the vehicle, and provides a ready means for the operator to test the operability of the control system.

Growing community of inventors

Peoria, IL, United States of America

Alan L Stahl