John A Gatza

US Patent:

56159358, Apr 1, 1997

Filed:

Sep 21, 1995

Appl. No.:

8/531930

Inventors:

Claus Beyer - West Bloomfield MI
John Gatza - Flint MI
Carlos Atoche - West Bloomfield MI
Sam Totonji - Novi MI

Assignee:

Robert Bosch GmbH - Stuttgart

International Classification:

B60T 866

US Classification:

303195

Abstract:

Under conditions which indicate all wheels are unstable, all have been in pressure decrease for a long time, and the vehicle reference velocity has been continuously negatively corrected for a long time, recovery are flags set on all wheels. If all recovery flags are set and four wheel drive axle oscillations are present and the reference velocity has not been in negative correction for too long, the gradient of the vehicle reference velocity is limited to a fixed lesser slope. If one or more recovery flags are set, other measures can be taken, including flattening of the vehicle reference velocity through gradual additions to the calculated vehicle acceleration, and giving longer pressure holds and delaying pressure increase. The recovery flag is reset separately on each wheel only when that specific wheel becomes completely stable. The presence of four wheel drive axle oscillations is determined based on the difference between the sum of the speeds of the front wheels and the sum of the speeds of the rear wheels.