Engine closed crankcase breathing system and air-driven breathing method

The invention provides an engine closed crankcase breathing system and a gas-driven breathing method, and belongs to the technical field of natural gas engine crankcase equipment. The breathing system comprises a crankcase, a respirator, a turbocharger, a bypass pipe, a first check valve and a second check valve. The crankcase is connected with an intake manifold, the intake manifold is provided with a throttle valve, one end of the throttle valve is connected with a turbocharger, the turbocharger is connected with a respirator, the crankcase is connected with the respirator, the respirator is connected with an oil pan of the crankcase, the respirator is connected with a first check valve, and the first check valve is connected with the turbocharger. The by-pass pipe is connected between the air outlet of the respirator and the air inlet manifold, and the second check valve is arranged on the by-pass pipe. According to the breathing system and the breathing method, a whole vehicle driving system, a pipeline a