FLUID SUPPLY SYSTEM AND METHOD OF OPERATING A FLUID SUPPLY SYSTEM

• US 20120055559A1
• Filed: 03/27/2010
• Published: 03/08/2012
• Est. Priority Date: 05/12/2009
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Pignard, Frederic
• Granted Patent: US 8,840,509 B2
• Time in Patent Office: Days
• US Class Current: 137/1
• CPC Class Codes: F16H 2061/0037 characterised by controlled fluid supply to lubrication circuits of the gearing
• CPC Class Codes: F16H 57/0413 Controlled cooling or heating of lubricant; Temperature control therefor
• CPC Class Codes: F16H 57/0446 the supply forming part of the transmission control unit, e.g. for automatic transmissions
• CPC Class Codes: Y10T 137/0318 Processes
• CPC Class Codes: Y10T 137/8593 Systems
• CPC Class Codes: Y10T 137/87338 Flow passage with bypass
• CPC Class Codes: Y10T 74/19991 Lubrication

Abstract

A fluid supply system is provided for cooling and lubricating a transmission of an automobile, which includes, but is not limited to a cooling channel for cooling the transmission and a lubrication channel for lubricating the transmission. The lubrication channel communicates with the cooling channel via a shift valve. The shift valve is adapted to provide at least a first valve status, by which the cooling channel is connected to the lubrication channel via only one first valve path, and a second valve status, by which the cooling channel is connected to the lubrication channel via at least the first valve path and by which the cooling channel is connected in addition via a second valve path to a bypass channel bypassing the lubrication channel. Since at least two different valve statuses optimized for low and high power are provided, it is possible to reduce unnecessary spin losses over the whole range of applied powers. Further, there is no need for unfavorable compromises, so that a reduced flow generation loss over the whole range of applied powers is provided, while sufficient cooling and lubricating is safeguarded at the same time.

Claims

1. A fluid supply system for cooling and lubricating a transmission of an automobile, comprising:

a cooling channel configured to cool the transmission; and

a lubrication channel configured to lubricate the transmission,

the lubrication channel is further configured to communicate with the cooling channel via a shift valve,

wherein the shift valve is configured to;

provide at least a first valve status by which the cooling channel is connected to the lubrication channel via a first valve path, and

provide a second valve status, by which the cooling channel is connected to the lubrication channel via at least the first valve path and by which the cooling channel is connected in addition via a second valve path to a bypass channel bypassing the lubrication channel.

2. The fluid supply system according to claim 1, further comprising an additional valve path that is configured to connect the cooling channel to the lubrication channel in addition to the first valve path in the second valve status.

3. The fluid supply system according to claim 2,

wherein the additional valve path is configured to communicates with a restrictor orifice,

wherein a flow section of the restrictor orifice is selected such that a lubrication flow {dot over (m)}_L, which comprises a sum of a mass flow {dot over (m)}_L1 of the first valve path and a second mass flow {dot over (m)}_L2 of the additional valve path, at maximal transferred power P_max is at least a minimum lubrication flow {dot over (m)}_L,min (P_max) at maximum transferred power P_max of the transmission.

4. The fluid supply system according to claims 1,

wherein the first valve path is configured to communicate with a main lubrication orifice, and

wherein a flow section of the main lubrication orifice is chosen such that at minimum transferred power P_min a lubrication flow {dot over (m)}_L is at least a minimum lubrication flow {dot over (m)}_L,min (P_min) of the transmission.

5. The fluid supply system according to claim 1, whereby

wherein the second valve path is configured to communicate with a bypass orifice, and

wherein a flow section of the bypass orifice is chosen such that a lubrication flow {dot over (m)}_L at maximal transferred power P_max is at least a minimum lubrication flow {dot over (m)}_L,min (P_max) at maximum transferred power P_max of the transmission.

6. The fluid supply system according to claim 1, wherein the shift valve is configured to switch from the first valve status to the second valve status, when a mass flow {dot over (m)}_C of the cooling channel exceeds a predetermined mass flow threshold, wherein the predetermined mass flow threshold is particularly chosen such, that the second valve status is applied when the first valve status provides a lubrication flow {dot over (m)}_L exceeding a required minimum lubrication flow {dot over (m)}_L,min (P) by a predefined tolerance value Δ

{dot over (m)}_switch.

7. The fluid supply system according to claim 1,

wherein the lubrication channel and the bypass channel are connected to an oil sump, and

wherein the cooling channel is fed from the oil sump.

8. The fluid supply system according to claim 1, wherein the shift valve is configured for actuation a solenoid interacting with a provided spring force.

9. The fluid supply system according to claim 1, wherein the shift valve comprises a greater number of outlet ports as compared to inlet ports.

10. The fluid supply system according to claim 1, wherein the cooling channel is upstream to the lubrication channel and the bypass channel.

11. An automatic transmission for an automobile, comprising:

a gear case;

an automatic gear assembly inside of the gear case;

a fluid supply system configured to cool and lubricate the automatic gear assembly, the fluid supply system, comprising;

a cooling channel configured to cool the automatic transmission; and

a lubrication channel configured to lubricate the automatic transmission, the lubrication channel is further configured to communicate with the cooling channel via a shift valve,

wherein the shift valve is configured to;

provide a first valve status by which the cooling channel is connected to the lubrication channel via a first valve path, and

provide a second valve status, by which the cooling channel is connected to the lubrication channel via the first valve path and by which the cooling channel is connected in addition via a second valve path to a bypass channel bypassing the lubrication channel.

12. The automatic transmission according to claim 11,

wherein the cooling channel is connected to a radiator, and

wherein the radiator is outside the gear case.

13. A method of operating a fluid supply system, comprising:

placing a shift valve into a first valve status;

switching the shift valve into a second valve status when a mass flow {dot over (m)}_C of a cooling channel exceeds a predetermined mass flow threshold,

wherein the predetermined mass flow threshold is particularly chosen such, that the second valve status is applied when the first valve status provides a lubrication flow {dot over (m)}_L exceeding a required minimum lubrication flow {dot over (m)}_L,min (P) by a predefined tolerance value Δ

{dot over (m)}_switch.