Patent ID: 6679134
Filing Date: 2004-01-20
Classification: B60W,F16H,Y10T

Abstract:
A transmission system comprising:a twin-clutch transmission comprising, a first shaft having gears for producing a first gear-ratio group, a second shaft having gears for producing a second gear-ratio group, a first clutch being capable of connecting the first shaft to an internal combustion engine so as to be selectable of one gear ratio of the first gear-ratio group, a second clutch being capable of connecting the second shaft to the engine so as to be selectable of one gear ratio of the second gear-ratio group; an engine revolution speed detector detecting an engine revolution speed; a gear ratio detector detecting a present gear ratio selected from the gear ratios of the first and second gear-ratio groups; and a control unit coupled to the transmission, the engine revolution speed detector and the gear ratio detector, the control unit being configured, to calculate an estimated engine revolution speed produced in the event that one of two gear ratios adjacent to the present gear ratio is selected by executing one of upshift and downshift, on the basis of the engine revolution speed, the present gear ratio and the one of the two gear ratios adjacent to the present gear ratio, to determine whether the estimated engine revolution speed is out of a normal engine revolution speed range, to disengage one of the first and second clutches which is engaged to select the gear-ratio group including the other of the two gear ratios adjacent to the present gear ratio when the estimated engine revolution speed is out of the normal operation speed range.