It has been over a half century since automatic transmission vehicles were introduced to the market, and many improvements in terms of reliability, performance, and cost have since been made.
As a result, over 70 percent of passenger cars in the Japanese market today are equipped with automatic transmissions.
Despite these advances, customer demand for quieter operation and reduced vibration in automatic transmission vehicles requires further improvements, particularly in the area of reduced shock and smooth response during shifting.
Technological improvements have been in progress to solve this problem by such means as reducing engine output during shifting, adapting feedback control and learning shift control.
Consequently, an advanced evaluation method for shift quality, with accuracy matching that of human feeling, is required to help improving the shift quality of automatic transmissions.
This report clarifies the effectiveness of a new shift quality evaluation method based on human feeling to the vehicle vibration and the torque fluctuation at the output shaft of automatic transmission, and also describes promising countermeasures to shift shock in the vehicle body.