US 2009/0211850 A1 · LUBRICATION CONTROL SYSTEM FOR AUTOMATIC TRANSMISSIONS

Abstract

An automatic transmission lubrication control system includes a modulating, spring biased spool valve and feedback circuit. One end of the spool valve is supplied with line pressure hydraulic fluid. The valve spool modulates a flow of lubricating hydraulic fluid from the cooler and its position is determined by a force balance between the line pressure, the regulated fluid output pressure to the lubrication system and the force of the biasing spring. In a reduced lubrication state, a signal from a transmission control module opens a solenoid valve to provide high pressure fluid to a three way check valve which closes the feedback circuit and applies high pressure fluid to the opposite end of the valve spool. This action moves the valve spool to a travel limit, closing off flow from the cooler. Hydraulic fluid from the torque converter feed is then routed to the lubrication system.

Claims18

Dependent claims

A lubrication control system for an automatic transmission comprising, in combination,

a multiple port spool valve having a valve spool disposed in a valve body, a first control port in said body for providing fluid to one end of said valve spool, a spring for biasing said valve spool away from said first port, a second control port in said body for providing fluid to an opposite end of said valve spool, a first inlet port, a first outlet port communicating with a first, larger fluid orifice, a second inlet port communicating with a second, smaller fluid orifice, and a first exhaust port communicating with a sump,
a control valve for selectively providing pressurized fluid,
a three way check valve communicating with said first outlet port, said first control port and said control valve,
whereby pressurized fluid provided to said second control port modulates a fluid flow between said first inlet port and said first outlet port when said control valve is closed and a fluid flow is established between said second inlet port and said first outlet port when said control valve is open.

1 more element

Dependencies are inferred from the claim text.

Lubrication control system for automatic transmissions

Life of this patent

Lubrication control system for automatic transmissions

Life of this patent

Abstract

Claims18