METHOD FOR USE WITH VEHICLE HAVING SELECTABLE TRANSFER CASE

• US 20120293317A1
• Filed: 05/20/2011
• Published: 11/22/2012
• Est. Priority Date: 05/20/2011
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Hanna, Ian L., Turzewski, John A.
• Granted Patent: US 9,358,883 B2
• Time in Patent Office: Days
• US Class Current: 340/441
• CPC Class Codes: B60K 2023/0883 manually actuated
• CPC Class Codes: B60K 23/08 for changing number of driven wheels , for switching from driving one axle to driving two or more axles B60K17/3515 takes precedence
• CPC Class Codes: B60W 50/14 Means for informing the driver, warning the driver or prompting a driver intervention

Abstract

A method for notifying, indicating or otherwise alerting a driver when it may be desirable to switch to a different transfer case mode. According to an exemplary embodiment, the method uses one or more environmental and/or vehicle conditions to evaluate a current transfer case mode and to determine if it is the most preferable or optimal mode. If the current transfer case mode is not optimal, then the method may recommend that the driver manually switch transfer case modes by notifying or alerting them through a visual and/or audio message. In one example, the method recommends a transition from a four-wheel mode to a two-wheel mode, or vice-versa, with a visual message on an instrument panel gauge.

Claims

1. A method for use with a vehicle having a selectable transfer case, comprising the steps of:

(a) receiving a vehicle sensor reading from a vehicle sensor, the vehicle sensor reading is generally representative of one or more vehicle conditions;

(b) receiving a transfer case sensor reading from a transfer case sensor, the transfer case sensor reading is generally representative of a current transfer case mode;

(c) using the one or more vehicle conditions to determine if the current transfer case mode is optimal; and

(d) when the current transfer case mode is not optimal, then alerting the driver that it is preferable to change from the current transfer case mode to a new transfer case mode.

2. The method of claim 1, wherein step (c) further comprises using at least one vehicle sensor reading from the following group to determine if the current transfer case mode is optimal:

a vehicle speed, a wheel speed, a wheel slip, or a wheel skid.

3. The method of claim 1, wherein step (a) further comprises receiving an environmental sensor reading from an environmental sensor, the environmental sensor reading is generally representative of one or more environmental conditions.

4. The method of claim 3, wherein step (c) further comprises using at least one environmental sensor reading from the following group to determine if the current transfer case mode is optimal:

an outside temperature, an outside humidity, or a road surface condition.

5. The method of claim 1, wherein step (c) further comprises comparing a plurality of conditions to corresponding thresholds to determine if the current transfer case mode is optimal.

6. The method of claim 5, wherein the plurality of conditions includes one or more vehicle conditions and one or more environmental conditions.

7. The method of claim 5, wherein all of the plurality of conditions must satisfy their corresponding thresholds in order for step (d) to alert the driver that it is preferable to change from the current transfer case mode to a new transfer case mode.

8. The method of claim 5, wherein only some of the plurality of conditions must satisfy their corresponding thresholds in order for step (d) to alert the driver that it is preferable to change from the current transfer case mode to a new transfer case mode.

9. The method of claim 6, wherein at least one of a wheel slip or a wheel skid must be less than a corresponding threshold in order for step (d) to alert the driver that it is preferable to change from the current transfer case mode to a new transfer case mode.

10. The method of claim 1, wherein step (c) further comprises using a first set of criteria when evaluating a change from a four-wheel mode to a two-wheel mode and a second set of criteria when evaluating a change from a two-wheel mode to a four-wheel mode, and the first set of criteria is more stringent than the second set of criteria.

11. The method of claim 1, wherein step (d) further comprises alerting the driver that it is preferable to change from the current transfer case mode to a new transfer case mode by visually displaying a message on a user interface for the driver to see.

12. A method for use with a vehicle having a selectable transfer case, comprising the steps of:

(a) receiving a transfer case sensor reading from a transfer case sensor, the transfer case sensor reading is generally representative of a current transfer case mode;

(b) if the current transfer case mode is a four-wheel mode, then using a first set of criteria to determine if a four-wheel mode to two-wheel mode transition is preferable;

(c) if the current transfer case mode is a two-wheel mode, then using a second set of criteria to determine if a two-wheel mode to four-wheel mode transition is preferable, wherein the first set of criteria is more stringent than the second set of criteria; and

(d) when the first or the second set of criteria is satisfied, then sending a message to the driver recommending a change in transfer case mode.

13. The method of claim 12, further comprising the step:

receiving a sensor reading from at least one of a vehicle sensor or an environmental sensor, a vehicle sensor reading is generally representative of one or more vehicle conditions and an environmental sensor reading is generally representative of one or more environmental conditions.

14. The method of claim 13, wherein at least one of the first or second sets of criteria uses at least one vehicle condition from the following group:

a vehicle speed, a wheel speed, a wheel slip, or a wheel skid

15. The method of claim 13, wherein at least one of the first or second sets of criteria uses at least one environmental condition from the following group:

an outside temperature, an outside humidity, or a road surface condition.

16. The method of claim 13, wherein both the first and second sets of criteria use at least one of a wheel slip or a wheel skid to determine if a transfer case mode transition is preferable.