Method of determining an operating state of a transmission latching valve

Patent metadata

Field	Value
Publication number	US-9574682-B2
Application number	US-201414217509-A
Country	US
Kind code	B2
Filing date	Mar 18, 2014
Priority date	Apr 1, 2013
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

A valve monitoring system includes a latching valve, a travel sensor, and a processor. The latching valve has a snap spring, a valve piston, and an inlet port. The travel sensor is for measuring travel of the valve piston between an activation pressure and a zero pressure. The processor is connected to the travel sensor for calculating a rate of travel of the valve piston and determining a latched state of the valve. In some example embodiments, the activation pressure is greater than a normal operating pressure. In some example embodiments, determining a latched state of the valve includes calculating a derivative of the rate of travel.

First claim

What I claim is:

1. A valve monitoring system comprising:
a latching valve with a snap spring, a valve piston, and an inlet port;
a travel sensor for measuring travel of the valve piston between an activation pressure and a zero pressure; and,
a processor connected to the travel sensor for calculating a rate of travel of the valve piston and determining a latched state of the valve, wherein:
the activation pressure is greater than a normal operating pressure;
determining the latched state of the valve includes calculating a derivative of the rate of travel; and,
the processor is configured to determine that the valve is in the latched state when the derivative shows little variation between 40% and 60% of a total travel distance of the valve piston.

2. The valve monitoring system of claim 1 wherein the processor is configured to determine that the valve is in the latched state when the derivative steadily decreases over time.

3. The valve monitoring system of claim 1 wherein the processor is configured to determine that the valve is in an unlatched state when an absolute value of the derivative decreases then increases over time.

4. The valve monitoring system of claim 1 wherein the processor is configured to determine that:
the valve is in the latched state when the derivative steadily decreases over time; and,
the valve is in an unlatched state when an absolute value of the derivative decreases then increases over time.

5. The valve monitoring system of claim 1 wherein the latching valve further comprises:
a housing;
an activation piston; and,
a seal operating between the housing and the activation piston to reduce a rate of travel of the activation piston.

Assignees

• Schaeffler Technologies Gmbh & Co Kg
• Schaeffler Technologies Ag

Inventors

• Ari Vural

Classifications

• F16K37/0083 Primary

  by measuring valve parameters · CPC title

• F16K31/003

  operated without a stable intermediate position, e.g. with snap action (F16K31/56 takes precedence) · CPC title

• Y10T137/0318

  Processes · CPC title

• F16K37/0041

  for measuring valve parameters (F16K37/0033 takes precedence) · CPC title

• Y10T137/8225

  Position or extent of motion indicator · CPC title