Line pressure control device for continuously variable transmission

Abstract

Abstract PURPOSE:To prevent the occurrence of an excess or a shortage in line pressure by judging a clutching condition on the clutch current of a magnetic clutch when there is an input trouble for an engine speed signal, and determining target line pressure from engine torque and a gear change ratio available from the clutching condition. CONSTITUTION:In controlling line pressure for a belt type continuously variable transmission by a control unit 40, output signals from each sensor 41-44 are first read in and then engine torque T is obtained from engine speed and the like at a calculation part 51. Also, necessary line pressure PLu per unit torque is obtained from an actual speed change ratio calculation part 45 on the basis of an actual speed change ratio (i). In this case, if the input trouble of an engine speed signal is detected by an abnormality detector 56, the clutch current Ic of a magnetic clutch 2 is detected and in a half-clutched condition, engine torque T1 is obtained from the clutch current Ic, while engine torque T2 obtained from the speed of a primary pulley and throttle opening in a fully coupled condition. And a target pressure level PL is obtained from the engine torque T-T2 and said line pressure PLu.

Inventors

• 👤 Kazunari Tezuka
• 👤 一成 手塚

Bibliographic Details