Patent attributes
A tanker vehicle for distributing liquid on a surface includes a chassis that supports a tank for holding the liquid. A fluid pump discharges the liquid from the tank and is driven by a hydraulic motor. A hydraulic system delivers hydraulic fluid to the motor through a supply line and returns the fluid to a tank through a return line. A bypass circuit is disposed between the supply line and the return line, bypassing the motor. The bypass circuit includes a system for providing a combination soft start and soft stop of the hydraulic motor that is configured to enable hydraulic fluid to flow from the supply line through the bypass circuit to the return line at a start of the hydraulic system and to flow from the return line through the bypass circuit to the supply line at a shutdown of the hydraulic system.