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

Claim 2

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 a lock-up state or a torque converter state, the control system comprising: means (203,220,231,233,234) for determining whether the automotive vehicle is operating in a predetermined lock-up range or not and for generating a lock-up signal (S L ) that indicates that the automotive vehicle is operating within said predetermined lock-up range; means (235,237,31) responsive to the presence of said lock-up signal for rendering said lock-up torque converter to operate 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; and 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.

Claim 3

A control system as claimed in claim 1, wherein the second pattern of the variation of said amount of exhaust gas recirculation provides a relatively small amount of exhaust gas recirculation as compared to that provided by the first pattern of the variation of said amount of exhaust gas recirculation.

Claim 4

A control system as claimed in claim 1 or 2, wherein the second pattern of variation of said spark timing provides a relatively small amount of spark advance as compared to that provided by the first pattern of variation of said spark timing.

Claim 5

A control system as claimed in claim 1, wherein said ignition timing control means comprises: a distributor (74) 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 that indicates 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 (V 4 ) with said second signal (V S ) and for controlling said spark advance unit in such a manner as to reduce a difference between said first signal and said second signal.

Claim 6

A control system as claimed in claim 1, wherein said ignition timing control means comprises: a distributor (74) having a spark advance unit, means (302) for sensing the amount of spark advance provided by said spark advance unit (93) and for generating a first signal (V 4 ) that indicates said amount of spark advance, means (301) for sensing an operating parameter that indicates an operating condition of the engine and for generating a second signal (V 5 ) that varies substantially in the second pattern of variation of said spark timing and a third signal (V 6 ) that varies substantially in the same manner as the variation of said second signal but slightly greater than said second signal, first comparator means (303) for comparing said first signal (V 4 ) with said third signal (V 6 ) and 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 (V 4 ) is greater than said third signal (V 6 ), and second comparator means (304) for comparing said first signal (V 4 ) with said second signal (V 5 ) 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 (V 5 ), 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,.

Claim 7

A control system as claimed in claim 1, wherein said exhaust gas recirculation control means comprises an exhaust gas recirculation conduit (78) having an EGR valve (79) for controlling flow of exhaust gas through said exhaust gas recirculation conduit, an EGR diaphragm device (80) for actuating said EGR valve (79) for controlling the opening of said EGR valve, a three-way valve (81), an atmospheric air admission valve (85), an EGR vacuum passage (83) having one end opening into said three-way valve and other end opening into said EGR diaphragm device, a manifold vacuum passage (82) having one end opening into said three-way valve and other end opening into a carburetor for the engine at a position where intake manifold vacuum builds up, a dilution passage (84) having one end opening into said three-way valve and other end opening into said atmospheric air admission valve, an atmosphere passage (86) having one end opening into said atmopsheric air admission valve and other end opening into the atmosphere, a bypass passage (88) having one end opening into said EGR vacuum passage and other end opening into said dilution passage, said three-way valve having a solenoid and valve means for normally establishing sole 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 sole communication between said one end of said EGR vacuum passage and said one end of said dilution passage (84) when said solenoid thereof is energized, said atmospheric air admission valve having a solenoid and valve means for preventing commuinication between said other end of said dilution passage and said other end of said atmosphere passage when said solenoid thereof is not energized and for allowing the communication between said other 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.

Claim 8

A control system as claimed in claim 2, wherein said ignition timing control means comprises: a distributor (74) having a vacuum advance unit with a spark advance diaphragm device (93) for actuating said vacuum advance unit, a second three-way valve (92), an atmosphere valve (95), a vacuum valve (96), a branch vacuum passage (89) having one end opening into said second three-way valve and other end opening into said manifold vacuum passage (82), a spark advance vacuum passage (94) having one end opening into said second three-way valve and other end opening into said spark advance diaphragm device, a bifurcated passage (97) having a first end opening into said three-way valve and a second end opening into said atmosphere valve (95) and a third end opening into said vacuum valve (96), respectively, a vacuum tank (91), a vacuum tank passage (99) having one end opening . into said vacuum valve and other end opening into said vacuum tank, said second three-way valve (92) having a solenoid and valve means for normally establishing sole communication between said one end of said spark advance vacuum passage and said one end of said branch vacuum passage when said solenoid thereof is not energized and for establishing sole communication between said one end of said spark advance vacuum passage and said first end of said bifurcated passage when said solenoid thereof is energized, said atmosphere valve (95) having a solenoid and valve means for normally preventing communication between said second end of said bifurcated passage and the atmosphere when said solenoid thereof is not energized and allowing the communication between said second end of said bifurcated passage and the atmosphere when said solenoid thereof is energized, said vacuum valve (96) having a solenoid and valve means for normally preventing communication between said third end of said bifurcated passage and said one end of said vaccum tank passage (99) when said solenoid thereof is not energized and allowing the communication between said third end of said bifurcated passage and said one end of said vacuum tank passage when said solenoid thereof is energized, means responsive to the presence of said lock-up signal for energizing said solenoid of said second three-way valve, means (302) for sensing spark advance vacuum within said spark advance vacuum passage (94) and for generating a first electric signal that indicates the sensed spark advance vacuum, means (301) for sensing intake manifold vacuum within said branch vacuum passage (89) and for generating a second electric signal that varies against the variation in the intake manifold vacuum in said second pattern of variation of said spark timing, means for comparing said first electric signal (V 4 ) with said second electric signal (V5) and responsive to the presence of said lock-up signal for periodically energizing said solenoid of said atmosphere valve only when said first electric signal (V 4 ) is greater than said second electric signal so as to admit atmospheric air into said spark advance vacuum passage (94) via said bifurcated passage (97) and via said second three-way valve (92) or for periodically energizing said solenoid of said vacuum valve only when said first electric signal (V 4 ) is smaller than said second electric signal (V 5 ) so as to apply vacuum from said vacuum tank to said spark advance vacuum passage, thereby to reduce a difference between said first electric signal and said second electric signal.

Claim 9

A control system as claimed in claim 2, wherein said ignition timing control means comprises: a distributor (74) having a vacuum advance unit with a spark advance diaphragm device (93) for actuating said vacuum advance unit, a second three-way valve (92), an atmosphere valve (95), a vacuum valve (96), a branch vacuum passage (89) having one end opening into said second three-way valve and other end opening into said manifold vacuum passage (82), a spark advance vacuum passage (94) having one end opening into said second three-way valve and other end opening into said spark advance diaphragm device, a bifurcated passage- (97.) having a first end opening into said three-way. valve and a second end opening into said atmosphere valve (95) and a third end opening into said vacuum-valve (96), respectively, a vacuum tank (91), a vacuum tank passage (99) having one end opening into said vacuum valve and other end opening into said vacuum tank, said second three-way valve (92) having a solenoid and valve means for normally establishing sole communication between said one end of said spark advance vacuum passage and said one end of said branch vacuum passage when said solenoid thereof is not energized and for establishing sole communication between said one end of said spark advance vacuum passage and said first end of said bifurcated passage when said solenoid thereof is energized, said atmosphere valve (95) having a solenoid and valve means for normally preventing communication between said second end of said bifurcated passage and the atmosphere when said solenoid thereof is not energized and allowing the communication between said second end of said bifurcated passage and the atmosphere when said solenoid thereof is energized, said vacuum valve (96) having a solenoid and valve means for normally preventing communication between said third end of said bifurcated passage and said one end of said vaccum tank passage (99) when said solenoid thereof is not energized and allowing the communication between said third end of said bifurcated passage and said one end of said vacuum tank passage when said solenoid thereof is energized, means responsive to the presence of said lock-up signal for energizing said solenoid of said second three-way valve, means (302) for sensing spark advance vacuum within- said spark advance vacuum passage (94) and for generating a first electric signal (V 4 ) that indicates the sensed spark advance vacuum, means (301) for sensing intake manifold vacuum within said branch vacuum passage (89) and for generating a second electric signal (V s ) that varies against the variation in the intake manifold vacuum in said second pattern of variation of said spark timing and for generating a third electric signal (V 6 ) that varies substantially in the same manner as the variation of said second signal but slightly greater than said second signal, first comparator means for comparing said first electric signal (V 4 ) with said third electric signal (V 6 ) and responsive to the presence of said lock-up signal for periodically energizing said solenoid of said atmosphere valve only when said first electric signal is greater than said third electric signal (V 6 ) so as to admit atmospheric air into said spark advance vacuum passage (94) via said bifurcated passage (97) and via said second three-way valve (92), and second comparator means for comparing said first electric signal (V 4 ) with said second electric signal (V 5 ) and responsive to the presence of said lock-up signal for periodically energizing said solenoid of said vacuum valve only when said first electric signal (V 4 ) is smaller than said second electric signal so as to apply vacuum from said vacuum tank to said spark advance vacuum passage, whereby the air admission or vacuum admission control ceases when said first electric signal (V 4 ) is greater than said second electric signal (V 5 ) and smaller than said third electric signal (V 6 ) '