PURPOSE: To suppress the increase of a cost by a method wherein only from the number of revolutions of an engine and the numbers of revolutions of the input and output shafts of a continuously variable speed change gear, the speed ration, the volume factor, the torque ration, and turbine torque of a fluid joint, and the speed ratio of the continuously variable speed change gear are determined, and therefrom, the line pressure of the continuously variable speed change gear is determined.
CONSTITUTION: The number Ne of revolutions of an engine and the input and output numbers of revolutions Nin and Nout of a continuously variable speed change gear (CVT) are read, a speed ration CTC of a torque converter (fluid joint) is then determined by a formula (3), and a volume factor C of the torque converter is then calculated from the map of a graph A. A torque ratio γTC is then determined by using the map of a graph B. A turbine torque Tt of the torque converter is determined according to a formula (4), and a speed ratio eCVT of the CVT is then determined based on a formula (5). In which case, a line pressure PL is determined by a formula (2), wherein k2Nout2 is a correction item of a centrifugal oil pressure, and k3 is a margin of a pressure. In consideration of the torque increase action of the torque converter, the PL is decided.
JUFUKU YASUNOBU
HAYASHI TAKASHI
OKUWAKI SHIGERU
Next Patent: CONTROL DEVICE FOR AUTOMATIC SPEED CHANGE GEAR