CONTROL SYSTEM FOR HYBRID VEHICLE

A control system for hybrid vehicles configured to improve energy efficiency by controlling a speed difference in a coupling. The hybrid vehicle comprises: a power split mechanism; an engine connected to a first rotary element; a first motor connected to the second rotary element; a second motor connected to the third rotary element; drive wheels to which a torque is delivered from the third rotary element; and a coupling comprising a drive member and a driven member. A controller is configured to change the speed difference in the coupling, and to change a speed or a torque of at least one of the first motor and the second motor after changing the speed difference in the coupling.