Downshift timing and engine brake control for automatic transmission
AssigneeNissan Motor Co., Ltd.
InventorsKoichi Hayasaki, Kazuhiko Sugano
Life of this patent
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Abstract
An electro-hydraulic control for an automatic transmission for an automotive vehicle, comprises a 3-2 timing valve, an overrun clutch control valve, an electromagnetic valve under the control of a computer, and a shuttle valve. The shuttle valve has a spool movable responsive to a line pressure variable with the engine throttle opening degree. The spool is movable between a first position where the overrun clutch control valve is under the control of the electromagnetic valve and a second position where the 3-2 timing valve is under the control of the electromagnetic valve.
Claims7
A control for an automatic transmission for an automotive vehicle having an engine, the transmission being adapted for shifting between different speed ratios and having a plurality of friction elements to effect shifting between speed ratios, the plurality of friction elements including an engine brake effecting friction element, the control comprising:
- a fluid source;
- means communicating with said fluid source for generating a line pressure which is variable with opening degree of a throttle of the engine;
- a timing valve;
- a control valve for the engine brake effecting friction element;
- electromagnetic means for generating a control pressure;
- a shuttle valve communicating with said timing valve, said control valve, and said electromagnetic means, said shuttle valve having a valve spool movable responsive to said line pressure between a first position where said control valve is under the control of said control pressure and said timing valve is not under the control of said control pressure, and a second position where said control valve is not under the control of said control pressure and said timing valve is under the control of said control pressure.
Dependencies are inferred from the claim text.