Gear change control method for automatic gearbox involves controlling duty cycle in defined manner, checking turbine speed for reduction and controlling fuel delivery accordingly

摘要

The gear change control method includes maintaining a duty cycle at 100 per cent in first gear of a D-driving range and determining if a first condition is fulfilled, whereby the choke angle is less than a defined value for a defined period, and whether a second condition is fulfilled for a defined period. If both conditions are fulfilled the duty cycle is controlled to a first value then controlled according to a reduction gradient, then a turbine speed is checked for a change. If so the fuel demand is reduced.