Control circuit for transmission variable displacement pump with improved efficiency
AssigneeFord Global Technologies, LLC
InventorsDerek B. Kinch, Mark Richard Dobson, Lev Pekarsky, Hrudaya Mahapatro
Life of this patent
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Abstract
The present disclosure relates to a control circuit for a variable displacement pump in a vehicle transmission, including: a regulator valve configured to regulate displacement control fluid to the variable displacement pump; and a response limiter in communication with the regulator valve, configured to mitigate pressure oscillations in the control circuit.
Claims19
A control circuit for a variable displacement pump in a transmission, comprising:
- a hydraulically actuated regulator valve that regulates fluid flow from the valve to the variable displacement pump to vary displacement of the pump;
- and
- a response limiter biasing the regulator valve to mitigate hydraulic pressure oscillations in the control circuit and biasing the valve toward pump outlet pressure hydraulic fluid flowing through the valve to the transmission and a displacement decrease circuit.
A transmission, comprising:
- a variable displacement pump;
- a control circuit controlling pump displacement through a hydraulically actuated regulator valve, which regulates fluid flow to the pump to vary displacement of the pump;
- a response limiter biasing the regulator valve to mitigate pressure oscillations in the control circuit;
- a line providing unrestricted hydraulic flow from a pump outlet to the valve, biasing the valve toward open communication from the pump outlet to a displacement decrease circuit;
- and
- wherein the response limiter biases the valve toward pump outlet pressure hydraulic fluid flowing through the valve to the transmission and the displacement decrease circuit.
A method of manufacturing a hydraulic control circuit for a variable displacement pump of a transmission, comprising:
- connecting a fluid sump to a pressure line;
- connecting the variable displacement pump to the pressure line;
- incorporating a hydraulically actuated regulator valve in the pressure line, the regulator valve configured to provide a displacement decrease pressure command to the pump and to regulate fluid flow from the valve to the pump to vary displacement of the pump;
- and
- incorporating a response limiter at one end of the regulator valve thereby reducing regulator valve positional response to hydraulic pressure oscillation inputs and the response limiter biases the valve toward pump outlet pressure hydraulic fluid flowing through the valve to the transmission and the displacement decrease circuit.
Dependencies are inferred from the claim text.