Control system for throttle released shifting by synchronous throttle control of an internal combustion engines

A control system for an internal combustion engine for an automotive vehicle, said vehicle having an accelerator pedal, and an automatic transmission, said automatic transmission having a plurality of speed clutches, said speed clutches each having an input side and an output side, said engine having an intake passage, and a throttle valve arranged in said intake passage, the control system comprising:

• accelerator position-detecting means for detecting release of said accelerator pedal;
• command-issuing means for issuing a command instructing gear shifting of said automatic transmission;
• neutral position-setting means responsive to said command issued by said command-generating means, for setting said automatic transmission into a neutral position when said accelerator position-detecting means detects said release of said accelerator pedal;
• throttle valve opening control means for controlling opening of said throttle valve such that rotational speed of said output side of one of said speed clutches to be selected for said gear shifting and rotational speed of said input side thereof become substantially equal to each other, when said automatic transmission is held in said neutral position by said neutral position-setting means;
• and
• clutch control means operable upon detection that said rotational speed of said output side of said one of said speed clutches and said rotational speed of said input side thereof become substantially equal to each other, for engaging said one of said speed clutches.