FIELD: transportation.
SUBSTANCE: working vehicle is proposed, comprising: a chassis; at least one traction device supporting the chassis; at least one hydraulic actuator connected to the chassis; and a hydraulic circuit made with the possibility to control at least one hydraulic actuator. Wherein the hydraulic circuit comprises: a source of a hydraulic fluid; a feeding device communicating with the source and at least one hydraulic actuator for feeding the hydraulic fluid; a first return pipeline from the feeding device to the source, and a second return pipeline from the feeding device to the source. The first return pipeline comprises a first flow control device and a cooler. The first flow control device allows the hydraulic fluid to pass through the first return pipeline, when the pressure in the hydraulic circuit exceeds the first passage pressure of the first flow control device. The second return pipeline bypasses the cooler on the first return pipeline. Wherein the second return pipeline comprises a second flow control device allowing the hydraulic fluid to pass through the second return pipeline, when the pressure in the hydraulic circuit exceeds the second passage pressure of the second flow control device. Also, the hydraulic circuit comprises a controller in communication with at least one of the first and the second flow control devices for controlling at least one of the first and the second passage pressures, and a control valve in communication with the controller and a first check valve. Wherein the control valve has: the first, neutral, position, which provides pressure relief from the first check valve; and the second position, which directs pressure to the first check valve to increase the first actuation pressure of the first check valve.
EFFECT: improving the control and efficiency of hydraulic fluid heating in a working vehicle.
20 cl, 4 dwg
