The development of hydraulic transmission In the early 20th century,a ship with high power and high speed turbine needs high power reduction gear to match with the propeller,and gear manufacturing technology can't meet the requirements.So German professor Gell-Mann Fottinger put forward a hydraulic loop transmission system consisting of tank,centrifugal pump,water pipe and hydroturbine; .Using the pump impeller and turbine with blades to substitute centrifugal pump and hydroturbine ,the tank and water pipe canceled,forming a hydrodynamic torque converter which had a co-working liquid circulation chamber; .German passenger ship Chellebitz'once used hydrodynamic torque converter .Afterwards,marine gear reducer replaced marine hydrodynamic torque converter,and hydrodynamic torque converter began using on the car .In the 1970 s,More than 90%of the cars,100%of the bus and 70%of the heavy duty vehicles and off-highway vehicles applied hydrodynamic torque converter in America.The major car companies in the world are producing hydraulic transmission two-gear,three-gear or four-gear automatic transmission at present.The development of hydraulic transmission • In the early 20th century, a ship with high power and high speed turbine needs high power reduction gear to match with the propeller, and gear manufacturing technology can’t meet the requirements . So German professor Gell-Mann Fottinger put forward a hydraulic loop transmission system consisting of tank , centrifugal pump, water pipe and hydroturbine; •Using the pump impeller and turbine with blades to substitute centrifugal pump and hydroturbine ,the tank and water pipe canceled, forming a hydrodynamic torque converter which had a co-working liquid circulation chamber; •German passenger ship ‘Chellebitz’ once used hydrodynamic torque converter ; •Afterwards, marine gear reducer replaced marine hydrodynamic torque converter , and hydrodynamic torque converter began using on the car ； •In the 1970 s , More than 90% of the cars, 100% of the bus and 70% of the heavy duty vehicles and off-highway vehicles applied hydrodynamic torque converter in America. The major car companies in the world are producing hydraulic transmission + two-gear, three-gear or four-gear automatic transmission at present