Gear preselect system for an electro-mechanical automatic transmission having dual input shafts

• US 6,286,381 B1
• Filed: 12/17/1999
• Issued: 09/11/2001
• Est. Priority Date: 12/17/1999
• Status: Expired due to Term

• Current Assignee: FCA US LLC (Stellantis NV)
• Original Assignee: Daimler Chrysler Corporation (Mercedes-Benz Group AG)
• Inventors: Reed, Richard G Jr., Cherry, Jeffrey R.
• Primary Examiner(s): Marmor, Charles A
• Assistant Examiner(s): PANG, ROGER L
• Application Number:
  US09/465,903
• Time in Patent Office: 634 Days
• Field of Search: 743/36.R, 743/39, 743/40
• US Class Current: 74/336.00R
• CPC Class Codes: F16H 2061/0216 Calculation or estimation of post shift values for different gear ratios, e.g. by using engine performance tables
• CPC Class Codes: F16H 59/0204 for automatic transmissions with means for range selection and manual shifting, e.g. range selector with tiptronic
• CPC Class Codes: F16H 61/0437 by using electrical signals F16H61/0403 and F16H61/061 take precedence
• CPC Class Codes: F16H 61/688 with two inputs, e.g. selection of one of two torque-flow paths by clutches
• CPC Class Codes: F16H 63/18 the final actuating mechanism comprising cams
• CPC Class Codes: Y10T 74/1926 Speed responsive

Abstract

A gear preselect system is provided for a transmission having dual input shafts in order to delay a gear preselect change until the last moment possible. The transmission controller determines the speed at which the next shift will occur and determines the preselect speed at which the preselect should occur in order for the preselect to take place prior to the time for shifting to the next gear. When the current vehicle speed is equal to or greater than the preselect speed, the transmission controller preselects the next higher gear.

Claims

1. A transmission, comprising:

dual input shafts, each including a plurality of drive gears in meshing engagement with a driven gear mounted on an output shaft; and

a controller for determining a speed at which a shift will occur and for determining a speed at which a preselect should occur based upon a vehicle acceleration and a predetermined time required to preselect a gear.

2. A gear preselect method is provided for a transmission including dual input shafts, each including a plurality of drive gears in meshing engagement with a respective driven gear mounted on an output shaft, comprising the step of:

determining a shift speed at which a shift will occur;

determining a preselect speed at which a gear preselect should occur; and

engaging a preselected gear on a non-engaged one of said dual input shafts when a vehicle speed reaches said preselect speed.