| 摘要 |
A tractor is disclosed having an engine 10 fitted with a speed governor, drive wheels 22, a transmission 20 connecting the engine 10 to the drive wheels 22, a controller 26 serving to select the effective transmission ratio, and an engine driven power take-off (PTO) shaft 24 for driving ancillary equipment connected to the tractor. When in a part load operating mode in which the PTO shaft 24 is connected to drive an implement and the tractor is moving, the governor is set to maintain the engine working point to follow a selected speed governor line (110, 112, 114) on the speed/load map of the engine. The controller 26 is operative to initiate a change in the transmission ratio when the engine speed cannot be maintained within the specified tolerance of the desired engine speed. |
