Method of and apparatus for controlling torque-down upon gear changing

An apparatus for controlling a torque-down of the present engine torque of an internal combustion engine upon gear changing of an automatic transmission at a predetermined demand for a rate of torque-down, comprising:

• a combustion torque down rate converting means for converting the predetermined demand for a torque-down rate into a down rate of combustion torque as a sum of engine torque and friction torque;
• a counter MBT down rate converting means for converting the down rate of combustion torque into a counter MBT down rate that is a down rate against a combustion torque at an ignition timing for a Minimum Advance for Best Torque (MBT ignition timing);
• and
• an ignition timing retard amount calculating means for calculating an amount of retard of ignition timing from the MBT ignition timing on the basis of the counter MBT down rate, for implementing the torque-down controlling of the engine.

A control apparatus provided to have a control communication with an internal combustion engine and an automatic transmission, and including a torque-down control unit for implementing a torque-down controlling of the internal combustion engine upon gear changing of the automatic transmission by cutting down a part of the present engine torque at a predetermined demand for a torque-down rate, wherein the torque-down control unit:

• converts the predetermined demand for a torque-down rate into a down rate of combustion torque;
• converts the down rate of combustion torque into a counter MBT down rate that is a down rate against a combustion torque at an ignition timing for a Minimum Advance for Best Torque (MBT ignition timing);
• calculates an amount of retard of ignition timing from the MBT ignition timing on the basis of the counter MBT down rate, for implementing the torque-down controlling of the engine;
• compares the above-calculated amount of retard of ignition timing from the MBT ignition timing with a predetermined value;
• and
• prohibits the ignition timing from being retarded while curtailing the supply of fuel when the above comparison indicates that the calculated amount of retard of ignition timing exceeds the predetermined value, for implementing the torque-down controlling of the engine.

A method of controlling a torque-down of the present engine torque of an internal combustion engine upon gear changing of an automatic transmission at a predetermined demand for a rate of torque-down, comprising:

• converting the predetermined demand for a torque-down rate into a down rate of combustion torque as a sum of engine torque and friction torque;
• converting the down rate of combustion torque into a counter MBT down rate that is a down rate against a combustion torque at an ignition timing for a Minimum Advance for Best Torque (MBT ignition timing);
• and
• calculating an amount of retard of ignition timing from the MBT ignition timing on the basis of the counter MBT down rate, for implementing the torque-down controlling of the engine.