| 摘要 |
<p>An automatic control system for a vehicular liquid sprayer includes a control circuit for receiving a liquid presure signal and a vehicle ground speed signal and operator accessible controls for delivering to the control circuit signals corresponding to a desired application rate, to the number of nozzles associated with the vehicular liquid sprayer and to the nozzle spacing. The operator may vary the input signal corresponding to desired application rate plus or minus a given percentage to compensate for tolerances in the liquid sprayer system. The control circuit calculates the liquid pressure necessary to achieve the desire application rate and the difference between this desire liquid pressure and the measured liquid pressure and produces control signals corresponding to this difference. A duty cycle control circuit converts these control signals to a cyclical control signal for driving a motor-driven flow control valve. The duty cycle of this cyclical control signal varies in proportion to the magnitude of the pressure difference. This duty cycle controlled signal is automatically modified to overcome inertia and motor lag time in a motor driven flow control valve, and to shut off the valve at a given minimum operating pressure.</p> |
