Caterpillar Inc.

Gregory A Menke

Javad Hosseini

Daniel Joseph Whiting

Brad K McCunn

Kevin G Meyer

Kenneth P Liesener

Keith F Harvey

Danial P Simon

David E Bullard

James G Starling

Pei-Ming Chang

Ken Liesener

Bradley K Mc Cunn

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.

Default modes of a transmission utilizing electro-hydraulic clutches

In one aspect of this invention, a system and process for controlling a fluid actuated retarder is disclosed. This includes an input mechanism and an electronic controller for receiving a signal from the input mechanism, including a value for a desired retarder control level. Also, there is a proportional solenoid valve that is actuated by the electronic controller. The proportional solenoid control valve is operatively connected to a proportional retarder spool valve and the proportional retarder spool valve is operatively connected to a fluid actuated retarder.

Method and system for controlling a fluid actuated retarder

An end-of-fill detection arrangement is provided in a power distribution system to detect when a clutch is fully filled and the pressure therein can be progressively increased to full engagement. The arrangement includes placing a position sensor in a pressure relief valve that is controlling the desired pressure level to respective clutches and directing the sensed position of the valving element therein to an electronic controller. The controller monitors the position of the valving element in the relief valve. Initiation of filling of a clutch results in the valving element moving from a bypassing position towards a flow blocking position. This movement is noted by the controller and when the valving element returns generally to its initial location, the clutch is filled. The controller notes the end-of-fill and provides a command signal to the proportional valve to progressively increase the pressure in the clutch until the clutch is fully engaged. The subject invention provides a simple arrangement that detects the end-of-fill.

End-of-fill detector arrangement for a fluid actuated clutch

A connector mechanism is provided to connect a spool in an air actuated valve to the diaphragm of an air actuating mechanism in order to permit rotational movement of the spool relative to the diaphragm. The connector mechanism includes a connector member having one end thereof firmly connected to the diaphragm and the other end thereof connected to one end of the spool and retained thereto by a retainer member which permits free rotation of the spool relative to the diaphragm during use of the air actuated valve.

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East Peoria, IL, United States of America

Gregory A Menke