Caterpillar Inc.

Brad K McCunn

Gregory A Menke

Javad Hosseini

Kevin G Meyer

Keith F Harvey

Ken Liesener

A method of controlling a transmission is provided. A command is received to engage a clutch having a chamber. A control valve is opened to allow pressurized fluid to flow from a fluid supply line into the clutch chamber. The pressure of the fluid within the fluid supply line is monitored as fluid flows through the control valve to enter the clutch chamber. A rate of change in the volume of fluid entering the chamber is determined based on the sensed pressure of the fluid within the fluid supply line. A fill point of the clutch chamber is detected when the rate of change in the volume of fluid entering the chamber is less than a volume differential threshold.

Fluid clutch fill detection system and method

In machines having electro-hydraulic transmission controls, it is desirable to ensure that in the event of an electrical malfunction or power failure the transmission responds appropriately. In the subject invention, a system is provided in a transmission which in the event of an individual clutch solenoid fault (short-to-battery, short-to-ground, and open circuit fault) keeps the machine in gear and protects the transmission from damage. A short-to-battery fault will allow shifting to an available gear that utilizes the faulted clutch. If there is a short-to-ground or open circuit fault then the transmission will latch the current gear or shift to a predetermined gear that does not utilize a faulted clutch.

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Peoria, IL, United States of America

Brad K McCunn