Lubrication control system for automatic transmissions
View Patent ↗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.
1. 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 is provided by said control valve through said three way check valve to said first control port,
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.
2. The lubrication control system of claim 1 further including an orifice disposed between said three way check valve and each of said first outlet port, said first control port and said control valve.
3. The lubrication control system of claim 1 further including a third inlet port communicating with an orifice, said third inlet port communicating with said first exhaust port when said control valve is open.
4. The lubrication control system of claim 1 further including a pressure sensing switch communicating with a fourth inlet port and said second inlet port through an orifice.
5. The lubrication control system of claim 1 wherein said spring is a compression spring.
6. The lubrication control system of claim 1 further including a lubrication manifold of an automatic transmission.
7. The lubrication control system of claim 1 further including a transmission cooler in fluid communication with said first inlet port.
8. A lubrication control system for an automatic transmission comprising, in combination,
a control valve for selectively providing pressurized fluid,
a multiple port spool valve having a valve body, a valve spool disposed in said body for movement between a modulating position and a limit position, a first control port for providing fluid to a first end of said valve spool and a second control port for providing said fluid to second end of said valve spool, means for biasing said valve spool to said limit position, a first inlet port, a first outlet port communicating with a larger fluid orifice, a second inlet port communicating with a smaller fluid orifice, and
a three way check valve communicating with said first outlet port, said first control port and said control valve,
whereby said valve spool modulates a flow of fluid from said first inlet port to said first outlet port when said control valve is closed and provides a flow of fluid from said second inlet port to said first outlet port when said control valve is open.
9. The lubrication control system for an automatic transmission of claim 8 further including a lubrication manifold in fluid communication with said first outlet port.
10. The lubrication control system for an automatic transmission of claim 8 wherein said valve body further includes a third inlet port in fluid communication with said first inlet port through a third orifice and an exhaust port communicating with a sump.
11. The lubrication control system for an automatic transmission of claim 8 further including a fluid pressure switch in fluid communication with said second inlet port and a fourth inlet port through a fourth orifice.
12. The lubrication control system for an automatic transmission of claim 11 further including a transmission control module having an input for receiving a signal from said fluid pressure switch and an output for controlling said control valve.
13. The lubrication control system for an automatic transmission of claim 11 further including a second exhaust port and wherein said fourth inlet port communicates with said second exhaust port when said control valve is open.
14. The lubrication control system for an automatic transmission of claim 8 wherein said means for biasing is disposed proximate said first control port.
15. The lubrication control system for an automatic transmission of claim 8 wherein said means for biasing is a compression spring.
16. The lubrication control system for an automatic transmission of claim 8 further including a transmission cooler having an output in fluid communication with said first inlet port.
17. The lubrication control system for an automatic transmission of claim 8 further including an orifice disposed between said three way check valve and each of said first outlet port, said first control port and said valve.
18. The lubrication control system for an automatic transmission of claim 8 wherein said valve spool includes four lands.