Automatic shift control system for an automatic transmission including a select-shift manual control

A transmission control system for a multiple ratio automatic transmission, said transmission comprising a first multiple ratio planetary gear set and a second simple planetary gear set arranged in series between an engine and a driven member, and an electronic transmission controller;

• multiple clutches and brakes for controlling relative motion of gear elements of said first and second gear sets to establish five forward driving speed ratios;
• a source of line pressure;
• a valve circuit establishing fluid pressure distribution from said pressure source to said clutches and brakes including at least two variable force solenoid valves and at least three on/off shift solenoid valves;
• a pressure build-up system forming a part of said valve circuit;
• brake servo control valve means in said circuit for controlling pressure distribution to said brakes and a clutch control valve means in said circuit for controlling pressure distribution to said clutches, each control valve means being in fluid pressure communication with said shift solenoid valves whereby the former are actuated by the latter selectively between two operating positions in accordance with the operating states of the latter;
• one of said variable force solenoid valves establishing controlled pressure distribution to the clutches and brakes for said multiple ratio planetary gear set through said brake servo control valve means and through said clutch control valve means;
• another of said variable force solenoid valves establishing controlled pressure distribution to the clutches and brakes for said simple planetary gear set through said brake servo control valve means and through said clutch control valve means;
• said shift solenoid valve means communicating hydraulically with said brake servo control valve means and said clutch control valve means for effecting shifting movement thereof to establish and disestablish pressure distribution paths to said clutches and brakes whereby speed ratio change patterns are obtained;
• a manual select system in said circuit between said electronic transmission controller and said clutch and brake servo control valve means having an automatic mode ratio change position for automatic ratio changes and multiple manual mode positions for effecting continuous manually selected ratios;
• said controller having output driver portions communicating with said variable force solenoid valves and said shift solenoid valves and signal input portions receiving engine, transmission and manual select system operating variables whereby said shift solenoid valve operating states are determined by said variables and by selected positions of said manual select system;
• said pressure build-up system comprising a first pressure modulator valve means communicating with a first of said variable force solenoid valves for distributing pressure through said clutch and brake servo control valve means to one of said clutches acting on gear elements of said first gear set and to one of said brakes for said first gear set and a second pressure modulator valve means communicating with a second of said variable force solenoid valves for distributing pressure through said clutch and brake servo control valve means to another of said clutches for said second gear set and to a brake for said second gear set whereby controlled clutch and brake pressure build-up is accomplished.

A transmission control system for a multiple ratio automatic transmission, said transmission comprising a first multiple ratio planetary gear set and a second simple planetary gear set arranged in series between an engine and a driven member, and an electronic transmission controller responsive to engine and transmission operating variables;

• multiple clutches and brakes for controlling relative motion of gear elements of said first and second gear sets to establish five forward driving speed ratios;
• a source of line pressure;
• a valve circuit establishing fluid pressure distribution from said pressure source to said clutches and brakes including at least two variable force solenoid valves and at least three on/off shift solenoid valves;
• a pressure build-up system forming a part of said valve circuit;
• brake servo control valve means in said circuit for controlling pressure distribution to at least one of said brakes and a clutch control valve means in said circuit for controlling pressure distribution to at least one of said clutches;
• first and second modulator control valve means communicating respectively with separate ones of said variable force solenoids for modulating said line pressure to produce a modulated variable force solenoid pressure;
• said first modulator control valve means communicating with said brake servo control valve means and said clutch control valve means whereby modulated variable force solenoid pressure is distributed through said clutch control valve means to one of said clutches acting on gear elements of said first gear set and to one of said brakes for said first gear set, said second servo modulator control valve means communicating with said second variable force solenoid valve for distributing pressure through said clutch control valve means to another of said clutches for said second gear set and to a brake for said second gear set whereby controlled clutch and brake pressure build-up is accomplished;
• said variable force solenoid valves establishing controlled pressure distribution to said clutches and brakes through said brake servo control valve means and through said clutch control valve means;
• said shift solenoid valves communicating hydraulically with said brake servo control valve means and said clutch control valve means for effecting shifting movement thereof to establish and disestablish pressure distribution paths to said clutches and brakes, whereby speed ratio change patterns are obtained as determined by the operating states of said shift solenoid valve means;
• and
• a manual select system in said circuit between said electronic transmission controller and said clutch control valve means and said brake servo control valve means having an automatic mode ratio change position for automatic ratio changes and multiple manual mode positions for effecting continuous manually selected ratios;
• said controller having output driver portions communicating with said variable force solenoid valves and said shift solenoid valves and signal input portions receiving engine, transmission and manual select system operating variables whereby said shift solenoid valve operating states are determined by said variables and by selected positions of said manual select system;
• the operating states of said variable force solenoid valves thereby determining the torque capacity of said clutches and brakes during operation including start-up torque capacity in any transmission ratio.