On-grade shift logic with provision for skip downshifts

Claim 1

An automated transmission system for variable speed variable acceleration vehicles having a throttle-controlled engine provided with a variable amount of fuel, a throttle controlling means having variable positions for controlling the amount of fuel supplied to the engine and a transmission having a plurality of gear ratio combinations selectively engagable between a transmission input shaft and a transmission output shaft, said transmission input shaft being operatively connected to said engine by a coupling device, said transmission system including an information processing unit having means for receiving a plurality of input signals including (1) an input signal indicative of the position of said throttle controlling means, and (2) an input signal indicative of the speed of said vehicle, said processing unit including means for processing said input signals in accordance with a predetermined logic rules to select a desirable gear ratio for a given combination of input signals and for generating command output signals whereby said transmission system is operated in accordance with said predetermined logic rules, and means associated with said transmission effective to actuate said transmission to effect engagement of one of said gear ratio combinations in response to said output signals from said processing unit, the system comprising by: said processing unit having means for processing said input signals to provide a value indicative of the acceleration of the vehicle, said predetermined logic rules having a subroutine, effective upon sensing conditions at which a downshift from any ratio greater than the third lowest ratio is normally required, effective to: (i) determine a first reference value (REF 1), determine a second reference value (REF 2) variable with the position of the throttle controlling means and determine a third reference value (REF 3) variable with the position of the throttle controlling means, said second reference value greater than said third reference value; (ii) compare the position of the throttle controlling means to said first reference value, (iii) compare the value indicative of vehicle acceleration to said second and then said third reference values, and (iv) if the position of the throttle controlling means is greater than said first reference value and the value indicative of vehicle acceleration is less than said second reference value but greater than said third reference value, select a direct single skip downshift (v) if the position of the throttle controlling means is greater than said first reference value and the value indicative of vehicle acceleration is less than said third reference value, select at least a double skip downshift.