Method for use with vehicle having selectable transfer case

Patent metadata

Field	Value
Publication number	US-9358883-B2
Application number	US-201113112453-A
Country	US
Kind code	B2
Filing date	May 20, 2011
Priority date	May 20, 2011
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

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.

First claim

The invention claimed is:

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 and an environmental sensor reading from an environmental sensor, the vehicle sensor reading is representative of one or more vehicle conditions and the environmental sensor reading is representative of one or more environmental conditions;
(b) receiving a transfer case sensor reading from a transfer case sensor, the transfer case sensor reading is representative of a current transfer case mode;
(c) when the current transfer case mode is a four-wheel mode then using the one or more vehicle conditions and the one or more environmental conditions in conjunction with a first set of criteria to determine if the four-wheel mode is optimal, when the current transfer case mode is a two-wheel mode then using the one or more vehicle conditions in conjunction with a second set of criteria to determine if the two-wheel mode is optimal, the first set of criteria for determining if the four-wheel mode is optimal includes a first plurality of thresholds with both vehicle condition thresholds and environmental condition thresholds where at least one of the first plurality of thresholds is a wheel slip or a wheel skid threshold and the first plurality of thresholds is used to evaluate a change from the current four-wheel mode to a two-wheel mode and the second set of criteria for determining if the two-wheel mode is optimal includes a second plurality of thresholds with vehicle condition thresholds where at least one of the second plurality of thresholds is a wheel speed or vehicle speed threshold and the second plurality of thresholds is used to evaluate a change from the current two-wheel mode to a four-wheel mode, and the first set of criteria is more stringent than the second set of criteria in that all of the first plurality of thresholds including the vehicle condition thresholds and environmental condition thresholds with the wheel slip or wheel skid threshold must be satisfied before determining an optimal transfer case mode whereas only some of the second plurality of thresholds including the vehicle condition thresholds with the wheel speed or vehicle speed threshold must be satisfied before determining an optimal transfer case mode; 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 four-wheel mode is optimal or the two-wheel mode is optimal: a vehicle speed, a wheel speed, a wheel slip, or a wheel skid.

3. The method of claim 1 , wherein step (c) further comprises using at least one environmental sensor reading from the following group to determine if the current four-wheel mode is optimal: an outside temperature, an outside humidity, or a road surface condition.

4. The method of claim 1 , wherein all of the plurality of vehicle conditions and environmental conditions must satisfy their corresponding vehicle condition thresholds and environmental condition thresholds, respectively, 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.

5. The method of claim 1 , 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.

6. 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.

Assignees

• Hanna Ian L
• Turzewski John A
• Gm Global Tech Operations Inc

Inventors

• Hanna Ian L
• Turzewski John A

Classifications

• B60K2023/0883

  manually actuated · CPC title

• B60K23/08 Primary

  for changing number of driven wheels {, for switching from driving one axle to driving two or more axles (B60K17/3515 takes precedence)} · CPC title

• B60W50/14

  Means for informing the driver, warning the driver or prompting a driver intervention · CPC title