METHOD OF AUTOMATIC SPEED CHANGE OF SELF-PROPELLED VEHICLE.

摘要

The present invention relates to a method of automatically changing the speed of a self-propelled vehicle having a retarder. An automatic transmission (16) is shifted automatically on the basis of a speed change point which is set in accordance with a vehicle speed. In order to secure a sufficient supply of a cooling oil to the retarder at the time of its operation and to prevent unnecessary speed change operation due to non-operation of an accelerator (51), a speed change point is moved beyond a normal speed change point toward a higher vehicle speed side when the accelerator is not operated and the retarder (61) is operated for a period longer than a set time.