Internal combustion engine, lubrication system, and engine oil strainer

An oil strainer, comprising a lubricating oil passage, and an oil inlet and an oil outlet respectively provided at two ends of the lubricating oil passage, and wherein the oil strainer further comprises a check valve which is arranged at the oil inlet and only allows a lubricating oil to flow into the lubricating oil passage;

• the oil strainer further comprises an oil return pressurized passage, and the oil return pressurized passage has one end in communication with the lubricating oil passage, and another end having an oil return port allowing a returning lubricating oil to flow in;
• and
• wherein a housing of the oil strainer is in a shape of a triangle, the housing is drilled to form a first passage and a second passage, the first passage extends through two corners of the housing, and the second passage is drilled from a remaining corner of the housing and is in communication with the first passage, two ends of the first passage are sealed by screw plugs respectively, the oil outlet and the oil return port are respectively opened on a sidewall of the first passage, the lubricating oil passage is defined by the second passage and a section of the first passage adjacent to the oil outlet, and the oil return pressurized passage is defined by a section of the first passage adjacent to the oil return port, the first passage and the second passage are connected by an arc-shaped transition section, and the arc-shaped transition section is bent toward the oil outlet.