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US 5,612,874 AGranted
Multiple ratio automatic transmission with solenoid operated valves for effecting pressure buildup
AssigneeFord Motor Company
InventorsWinfried F.-X. Schulz, Johann Kirchhoffer
Life of this patent
Estimating the term…
Abstract
A control system for a multiple ratio transmission including a hydrokinetic torque converter with a pressure actuated friction bypass clutch, pressure actuated clutches and brakes controlling ratio changes in forward drive and for effecting reverse drive, a solenoid operated pressure control that develops an optimum clutch and brake pressure for smooth engagement and for increased torque capacity during start-up, and separate solenoid regulator valves for ratio shift valve control and for bypass clutch pressure control.
Claims12
A control system for an automatic transmission comprising multiple ratio gearing elements with gear ratios defining plural torque flow paths between a throttle controlled engine and a driven shaft, said control system comprising;
- pressure actuated clutch and brake means for controlling the relative motion of said gearing elements, an engine driven line pressure pump, at least one transmission ratio shift valve means for selectively distributing pressure developed by said pump to said clutch and brake means to effect ratio changes;
- a pressure operated reverse clutch in said torque flow path between said engine and said gearing elements, said pump developing a line pressure, said control system providing a fluid pressure distribution path to said reverse clutch for activating said reverse clutch;
- a main regulator valve means communicating with said pump for maintaining said line pressure;
- a solenoid operated pressure control valve means for modulating said line pressure to produce a control pressure;
- means for establishing control signals determined by operating variables of said transmission and said engine including engine throttle position and engine speed;
- an electronic microprocessor having a memory portion with storage registers containing ratio shift and line pressure control strategy and means for distributing said control signals to said solenoid operated pressure control valve means;
- said main regulator valve means including a line pressure booster valve means for augmenting line pressure maintained by said main regulator valve means;
- a control pressure valve means communicating with said line pressure booster valve means and with said solenoid operated pressure control valve means for establishing control pressure values that determine a first functional relationship between said line pressure and said control pressure and for establishing boosted control pressure values that determine a second functional relationship between said line pressure and said control pressure thereby providing sufficient clutch and brake capacity during vehicle start-up;
- a reverse clutch pressure modulator valve means in said control system communicating with said main regulator valve means, said solenoid operated pressure control valve means and said reverse clutch for modulating pressure buildup in said reverse clutch upon activation of said reverse clutch whereby reverse clutch engagement is cushioned.
6 more elements
A control system for an automatic transmission comprising multiple ratio gearing elements, a hydrokinetic torque converter having an engine-driven impeller and a turbine, said turbine being connected to torque input portions of said transmission, said converter including pressure operated bypass clutch means for connecting said impeller to said turbine, a driven shaft connected to torque output portions of said transmission, said control system comprising;
- pressure actuated clutch and brake means for controlling the relative motion of said gearing elements, an engine driven line pressure pump, at least one transmission ratio shift valve means for selectively distributing pressure developed by said pump to said clutch and brake means to effect ratio changes;
- at least one solenoid valve means for distributing actuating pressure to said shift valve means to effect ratio changes;
- a second solenoid valve means for distributing actuating pressure to said converter bypass clutch means;
- and
- a solenoid pressure regulator valve means for modulating pressure developed by said pump and supplying modulated pressure to said second solenoid valve means whereby the regulating characteristics of each of said solenoid pressure regulator valve means can be calibrated independently of the calibration requirements of the other solenoid pressure regulator valve means;
- said one solenoid valve means being an on-off solenoid valve means and said second solenoid valve means being a pulse width modulated solenoid valve means, said control system including an electronic microprocessor having a memory portion with storage registers containing ratio shift strategy, bypass clutch control strategy and line pressure control strategy and means for distributing actuating signals to each of said solenoid valve means in response to transmission and engine operating variables;
- means for monitoring the speed of said turbine and developing a turbine speed signal;
- said microprocessor including means for receiving said turbine speed signal and for timing the duration of said turbine speed signal when it is within a predetermined maintained turbine speed range, and means for limiting said distribution of said actuating signals for said solenoid pressure regulator valve means when turbine speed is not within said predetermined range for a predetermined period.
5 more elements
A control system for an automatic transmission for an automotive vehicle comprising multiple ratio gearing elements with gear ratios defining plural torque flow paths with multiple torque ratios between an engine and a driven shaft, said control system including;
- pressure actuated clutch and brake means for controlling the relative motion of said gearing elements, an engine driven line pressure pump, at least one transmission ratio shift valve means for selectively distributing line pressure developed by said pump to said clutch and brake means to effect ratio changes;
- a pressure operated forward drive clutch in said torque flow path between said engine and said gearing elements, said pump developing a line pressure, said control system defining a fluid pressure distribution path for said forward clutch for activating said forward clutch;
- a main regulator valve means communicating with said pump for maintaining said line pressure;
- a solenoid operated pressure control valve means for modulating said line pressure to produce a control pressure;
- means for establishing control signals determined by operating variables of said transmission and said engine including engine throttle position and engine speed;
- an electronic microprocessor having a memory portion with storage registers containing ratio shift and line pressure control strategy and means for distributing said control signals to said solenoid operated pressure control valve means;
- said regulator valve means including a line pressure booster valve means for augmenting line pressure maintained by said main regulator valve means;
- a control pressure valve means communicating with said line pressure booster valve means and with said solenoid operated control valve means for establishing control pressure values that determine a first functional relationship between said line pressure and said control pressure and for establishing increased pressure values that determine a second functional relationship between said line pressure and said control pressure thereby providing sufficient clutch and brake capacity during vehicle start-up;
- said clutch and brake means including a forward drive clutch that is engaged during forward drive;
- and
- a forward drive clutch pressure modulator valve means communicating with said forward drive clutch for modulating said pressure distributed to said forward clutch upon engagement of said forward clutch whereby forward clutch engagement is cushioned.
8 more elements
Dependencies are inferred from the claim text.