PROCEDURE FOR AUTOMATIC REPLACEMENT SELECTION IN A VEHICLE TRANSMISSION

Abstract

Abstract PCT No. PCT/SE81/00337 Sec. 371 Date Jul. 27, 1982 Sec. 102(e) Date Jul. 27, 1982 PCT Filed Nov. 19, 1981 PCT Pub. No. WO82/01853 PCT Pub. Date Jun. 10, 1982.Method for automatic gear selection in a vehicle power transmission, said selection being catered for by a control system including an electronic unit (1) which, in response to signals representing vehicle speed and engine load, coacts with a programmable read-only memory PROM (28), in which there are stored, for each gear position, alternative speed limits for changing gear to neighboring gears and also limiting values relating to speed change and engine load for selection between said alternative speed limits. To eliminate the risk of unsuitable gear selection for heavy vehicles, e.g. in conjunction with changing gear on a hill, the invention is essentially distinguished in that during travel, data on speed change and engine load are stored in a random access memory RAM (29); that the speed value most recently stored in said RAM before the initiation of the gear selection is compared, together with values stored in said RAM and relating to speed change and engine load at a certain instant before the initiation of the speed change, with values stored in said PROM and relating to speed, speed change and engine load, respectively; that said comparison results in the choice of a certain gear; that in the electronic unit (1) there is generated an output signal representing the selected gear; and that said output signal is fed to an operative means for indicating and/or engaging the selected gear.

Inventors

• 👤 K G Magnusson
• 👤 H V Stahl

Bibliographic Details