Assistant positioning device and assistant positioning method using same

The invention discloses an assistant positioning device which is used for carrying out assistant positioning and guaranteeing the coaxiality of a hole K1 in an engine flywheel housing and a hole K2 in an air cylinder body. The assistant positioning device comprises a positioning sleeve and a flywheel housing positioning rod. The positioning sleeve is provided with a hollow boss, the outer diameter of the hollow boss is matched with that of the hole K2 in the air cylinder body, and the positioning sleeve is fastened to the air cylinder body through a first bolt. The flywheel housing positioning rod is installed in the hole K1 in the flywheel housing and provided with a rod part and a positioning boss, the rod part is inserted into a hole of the hollow boss of the positioning sleeve, the positioning boss abuts upon the outside of the positioning sleeve, and the flywheel housing positioning rod is fastened to an air cylinder cover through a second bolt. The invention further discloses a positioning method using