Development of an electronically controlled four-speed automatic transmission with a D-range neutral control system 2000-05-0025
We have developed an electronically controlled four-speed
automatic transmission with a "D-range neutral control
system" for vehicles of small piston displacements (0.66 to
1.0 liter). When the vehicle is stationary with the engine idling,
the system reduces the pressure being supplied to the clutch,
thereby creating a neutral clutch condition. This helps reduces
fuel consumption of the stationary vehicle without intervention of
The non-intervention, however, can cause discomfort for the
driver when the system is engaged and disengaged as the vehicle
condition (i.e., engine revolution speed, vibration or noise
transmitted to the vehicle) may change noticeably.
Such a cause of discomfort that surfaced during the system
development stage was thoroughly investigated and successfully
eliminated by improving the method of control.