Gear-shift control system of automatic transmission for motor vehicle

• US 5,679,092 A
• Filed: 10/05/1995
• Issued: 10/21/1997
• Est. Priority Date: 10/21/1994
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Otsubo, Hideaki, Nakawaki, Yasunori
• Primary Examiner(s): Bonck, Rodney H.
• Assistant Examiner(s): RODRIGUEZ, SAUL
• Application Number:
  US08/538,991
• Time in Patent Office: 747 Days
• Field of Search: 477/97, 180/197, 364/426.03, 364/426.02
• US Class Current: 477/97
• CPC Class Codes: B60K 28/165 acting on elements of the vehicle drive train other than the propulsion unit and brakes, e.g. transmission, clutch, differential acting on brakes B60T8/17
• CPC Class Codes: F16H 2059/506 Wheel slip
• CPC Class Codes: F16H 2061/0227 Shift map selection, i.e. methods for controlling selection between different shift maps, e.g. to initiate switch to a map for up-hill driving
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals
• CPC Class Codes: F16H 61/686 with orbital gears

Abstract

A gear-shift control system of an automatic transmission, in which gear shift schedule is appropriately changed-over in correspondence with the change of a road surface situation. Low-friction road surface detection device detects a low-friction road surface so as to select the gear shift schedule for the low-friction road surface adopted to start the motor vehicle with second gear. After the selection, a holding device holds the gear shift schedule for the low-friction road surface until an accelerator is pressed next.

Claims

1. A gear-shift control system of an automatic transmission for a motor vehicle having means for detecting whether a road on which said vehicle is running has a low-friction road surface or a high-friction road surface, wherein gear shift schedule for the low-friction road surface adapted to start said motor vehicle at a high-speed gear stage is selected when the low-friction road surface is detected, whereas gear shift schedule for the high-friction road surface adapted to start said motor vehicle at a low-speed gear stage is selected when the high-friction road surface is detected, and wherein a gear shift is controlled in conformity with the selected gear-shift schedule, comprising:

means for detecting a press of an accelerator pedal; and

means for holding the gear shift schedule for said low-friction road surface until a next press of the accelerator pedal is detected, if said gear shift schedule for said low-friction road surface is once selected according to said detected result of the road surface.