Patent ID: 7678015

Claim:
A power train control system for a mobile machine, comprising: a power source configured to produce a power output; a transmission device operatively connected to receive the power output and propel the mobile machine; wherein the transmission device comprises a fixed ratio transmission unit comprising a plurality of available fixed output ratios; and a control module configured to: receive an indication of a power demand; receive an indication of a current travel speed of the mobile machine; reference the power demand and the current travel speed with a power train efficiency map to determine a first desired power source speed; and control operation of the transmission device to bring a speed of the power source within a predetermined amount of the first desired power source speed; wherein the control module comprises a plurality of power train efficiency maps, each of the plurality of power train efficiency maps corresponding with one of the plurality of available fixed output ratios, and wherein the first desired power source speed is associated with a current fixed output ratio, and wherein the control module is configured to: determine a second desired power source speed associated with an upper bounding fixed output ratio, and a third desired power source speed associated with a lower bounding fixed output ratio; compare a power train efficiency value corresponding to the first desired power source speed with a power train efficiency value corresponding to the second desired power source speed and a power train efficiency value corresponding to the third desired power source speed; and shift the fixed ratio transmission unit to the one of the fixed output ratios having the corresponding highest power train efficiency.