Control system for engine of automotive vehicle equipped with lock-up type automatic transmission

A control system for an engine of an automotive vehicle equipped with a lock-up type automatic transmission that includes a torque converter with a lock-up clutch, the torque converter being shiftable into either a lock-up state or a torque converter state, the control system comprising:

• means for determining whether the automotive vehicle is operating in a predetermined lock-up range and for generating a lock-up signal that indicates that the automotive vehicle is operating within said predetermined lock-up range;
• means responsive to the presence of said lock-up signal for operating said lock-up torque converter in the lock-up state;
• exhaust gas recirculation control means responsive to the absence of said lock-up signal for varying the amount of exhaust gas recirculation in a first pattern which provides suitable exhaust gas recirculation for operation of the engine when the lock-up torque converter operates in the torque converter state, and responsive to the presence of said lock-up signal for varying the amount of gas recirculation in a second pattern which provides suitable exhaust gas recirculation for operation of the engine when the lock-up torque converter operates in the lock-up state;
• ignition timing control means responsive to the absence of said lock-up signal for varying a spark timing in a first pattern which provides suitable spark timing for operation of the engine when the torque converter operates in the torque converter state, and responsive to the presence of said lock-up signal for varying a spark timing in a second pattern which provides suitable spark timing for operation of the engine when the torque converter operates in the lock-up state,
• said ignition timing control means comprising:
• a distributor having a spark advance unit;
• means for sensing the amount of spark advance provided by said spark advance unit and for generating a first signal indicative of said amount of spark advance;
• means for sensing an operating parameter that indicates an operating condition of the engine and for generating a second signal that varies substantially in the second pattern of variation of said spark timing;
• and
• means for comparing said first signal with said second signal and for controlling said spark advance unit to reduce a difference between said first signal and said second signal.

A control system for an engine of an automotive vehicle equipped with a lock-up type automatic transmission that includes a torque converter with a lock-up clutch, the torque converter being shiftable into either a lock-up state or a torque converter state, the control system comprising:

• means for determining whether the automotive vehicle is operating in a predetermined lock-up range and for generating a lock-up signal that indicates that the automotive vehicle is operating within said predetermined lock-up range;
• means responsive to the presence of said lock-up signal for operating said lock-up torque converter in the lock-up state;
• exhaust gas recirculation control means responsive to the absence of said lock-up signal for varying the amount of exhaust gas recirculation in a first pattern which provides suitable exhaust gas recirculation for operation of the engine when the lock-up torque converter operates in the torque converter state, and responsive to the presence of said lock-up signal for varying the amount of exhaust gas recirculation in a second pattern which provides suitable exhaust gas recirculation for operation of the engine when the lock-up torque converter operates in the lock-up state;
• ignition timing control means responsive to the absence of said lock-up signal for varying a spark timing in a first pattern which provides suitable spark timing for operation of the engine when the torque converter operates in the torque converter state, and responsive to the presence of said lock-up signal for varying a spark timing in a second pattern which provides suitable spark timing for operation of the engine when the torque converter operates in the lock-up state,
• said ignition timing control means comprising:
• a distributor having a spark advance unit;
• means for sensing the amount of spark advance provided by said spark advance unit and for generating a first signal indicative of said amount of spark advance;
• means for sensing an operating parameter that indicates an operating condition of the engine and for generating a second signal that varies substantially in the second pattern of variation of said spark timing and a third signal that varies substantially in the same manner as said second signal and of slightly greater magnitude than said second signal in at least one region thereof;
• first comparator means for comparing said first signal with said third signal, said first comparator being responsive to the presence of said lock-up signal for causing said spark advance unit to decrease the amount of spark advance only when said first signal is greater than said third signal;
• and
• second comparator means for comparing said first signal with said second signal and responsive to the presence of said lock-up signal for causing said spark advance unit to increase the amount of spark advance only when said first signal is smaller than said second signal, whereby the increase or decrease control of said spark advance unit ceases when said first signal is greater than said second signal and smaller than said third signal.

A control system for an engine of an automotive vehicle equipped with a lock-up type automatic transmission that includes a torque converter with a lock-up clutch, the torque converter being shiftable into either a lock-up state or a torque converter state, the control system comprising:

• means for determining whether the automotive vehicle is operating in a predetermined lock-up range and for generating a lock-up signal that indicates that the automotive vehicle is operating within said predetermined lock-up range;
• means responsive to the presence of said lock-up signal for operating said lock-up torque converter in the lock-up state;
• exhaust gas recirculation control means responsive to the absence of said lock-up signal for varying the amount of exhaust gas recirculation in a first pattern which provides suitable exhaust gas recirculation for operating of the engine when the lock-up torque converter operates in the torque converter state, and responsive to the presence of said lock-up signal for varying the amount of exhaust gas recirculation in a second pattern which provides suitable exhaust gas recirculation for operation of the engine when the lock-up torque converter operates in the lock-up state;
• ignition timing control means responsive to the absence of said lock-up signal for varying a spark timing in a first pattern which provides suitable spark timing for operation of the engine when the torque converter operates in the torque converter state, and responsive to the presence of said lock-up signal for varying a spark timing in a second pattern which provides suitable spark timing for operation of the engine when the torque converter operates in the lock-up state;
• said exhaust gas recirculation control means comprising:
• an exhaust gas recirculation conduit having an EGR valve for controlling flow of exhaust gas through said exhaust gas recirculation conduit;
• an EGR diaphragm device for actuating said EGR valve for controlling the opening of said EGR valve;
• a three-way valve;
• an atmospheric air admission valve, an EGR vacuum passage having one end opening into said three-way valve and another end opening into said EGR diaphragm device;
• a manifold vacuum passage having one end opening into said three-way valve and another end opening into a carburetor for the engine at a position where intake manifold vacuum builds up;
• a dilution passage having one end opening into said three-way valve and another end opening into said atmospheric air admission valve;
• an atmosphere passage having one end opening into said atmospheric air admission valve and another end opening to the atmosphere;
• a bypass passage having one end opening into said EGR vacuum passage and another end opening into said dilution passage;
• said three-way valve having a solenoid and valve means for normally establishing communication between said one end of said EGR vacuum passage and said one end of said manifold vacuum passage when said solenoid thereof is not energized and for establishing communication between said one end of said EGR vacuum passage and said one end of said dilution passage when said solenoid thereof is energized;
• said atmospheric air admission valve having a solenoid and valve means for preventing communication between said another end of said dilution passage and said another end of said atmosphere passage when said solenoid thereof is not energized and for establishing communication between said another end of said dilution passage and said one end of said atmosphere passage when said solenoid thereof is energized;
• and
• means responsive to the presence of said lock-up signal for energizing said solenoid of said three-way valve and periodically energizing said solenoid of said atmospheric air admission valve.