Speed change control system for vehicle

A speed change control system for a vehicle, comprising:

• an engine;
• and
• a speed change mechanism that is connected to the engine,
• wherein the speed change mechanism is adapted to shift an operating mode among
• a first continuously variable mode in which a speed of the engine may be varied continuously,
• a second continuously variable mode in which the speed of the engine may also be varied continuously, and
• a fixed mode in which a speed ratio between the engine and a pair of drive wheels is fixed to a predetermined value,
• the control system comprising a controller that controls the speed change mechanism,
• wherein the controller is configured to
• shift the operating mode between the first continuously variable mode and the second continuously variable mode via the fixed mode when a required drive force to propel the vehicle is increased,
• increase the speed of the engine to a first target speed from a point at which the operating mode is shifted from the fixed mode to the second continuously variable mode,
• further increase the speed of the engine to a second target speed calculated based on the required drive force, and
• set the first target speed to a smaller value with an increase in at least any one of
• a first elapsed time from a point at which the required drive force is increased to a point at which the operating mode is shifted from the fixed mode to the second continuously variable mode, and
• a second elapsed time from a point at which a change rate of longitudinal acceleration of the vehicle is reduced less than a predetermined value to the point at which the operating mode is shifted from the fixed mode to the second continuously variable mode.