Patent ID: 8683794

Claim:
A control device of a vehicle that is applied to a vehicle having a hydrostatic transmission (HST) configured to include a hydraulic pump connected to an output shaft of an engine, a hydraulic motor connected to a drive wheel, and a closed circuit linking the hydraulic pump and the hydraulic motor, the control device comprising: vehicle travel direction detection means for detecting a travel direction of the vehicle by detecting a shift position operated by an operator; pressure detection means for detecting a pressure of pressurized oil on one port side of the hydraulic pump and on the other port side of the hydraulic pump by detecting the pressure of the pressurized oil in an oil path of the closed circuit; and a controller, wherein the controller inputs a detected output of the vehicle travel direction detection means and a detected output of the pressure detection means, when the detected vehicle travel direction is forward travel or neutral, executes a calculation of a value obtained by reducing the detected pressure of the pressurized oil on the other port side from the detected pressure of the pressurized oil on the one port side as a pressure difference obtained by reducing the pressure on the suction port side of the hydraulic pump from the pressure on the discharge port side of the hydraulic pump, when the detected vehicle travel direction is reverse travel, executes a calculation of a value obtained by reducing the detected pressure of the pressurized oil on the one port side from the detected pressure of the pressurized oil on the other port side as a pressure difference obtained by reducing the pressure on the suction port side of the hydraulic pump from the pressure on the discharge port side of the hydraulic pump, and only when the calculated pressure difference changes from a positive value to a negative value and the pressure difference becomes a negative, executes control as to limit at least one of a throttle amount of the engine and a capacity of the hydraulic pump, such that overrun is suppressed in at least one of the hydraulic engine, the hydraulic pump, and the hydraulic motor in proportion as the pressure on the suction port side of the pump become greater than the pressure on the discharge port side of the hydraulic pump.