| 摘要 |
A fluid-transfer system includes a pump, a valve member for metering fluid pumped by the pump, and controls that regulate the position of the valve member. The controls may include an electric actuator operable to generate movement of the valve member in a first direction using activation current. The controls may also include one or more springs that provide resistance force that urges the valve member in a second direction, opposite the first direction. A spring rate of the resistance force may vary as a function of the position of the valve member in such a manner that a relationship between a flow rate of the fluid pumped through the pump and the activation current is more linear than a relationship between a position of the valve member and the activation current.
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