Heat preservation and pressurization method for self-heat-preservation type self-pressurization oil tank

The invention relates to a heat preservation and pressurization method for a self-heat-preservation type self-pressurization oil tank, belongs to the technical field of self-pressurization oil tanks, and solves the problems that in the prior art, the pipeline pressure loss of a hydraulic system is increased, the driving capacity is reduced, and the response rapidity of a hydraulic execution element is affected at the low temperature of the self-pressurization oil tank. The invention provides a heat preservation and pressurization method of a self-heat preservation type self-pressurization oil tank. The heat preservation and pressurization method comprises the steps that 1, low-pressure oil is injected into a low-pressure oil return cavity, high-pressure oil is injected into a high-pressure oil cavity, the low-pressure oil is preliminarily compressed, and pressurization is conducted; 2, the high-pressure oil liquid in the high-pressure oil cavity flows into a low-pressure oil return cavity, and heating and hea