Ignition Syste m
Descriptio n
Ignition Timin g Control :
Th e programme d ignitio n (PGM-IG ) use d i n thi s engin e provide s optimu m contro l o f ignitio n timing . A microcompute r
determine s th e timin g i n respons e t o engin e spee d an d intak e ai r flo w mass . Th e inpu t signal s ar e transmitte d b y th e
TDC/CKP/CY P sensor , throttl e positio n (TP ) sensor , engine coolant temperatur e (ECT ) sensor , an d MA F sensor . Thi s sys -
tem , whic h i s no t dependen t o n a governo r o r vacuu m diaphragm , i s capabl e o f settin g lea d angle s wit h complicate d char -
acteristic s whic h canno t b e provide d b y conventiona l governor s o r diaphragms .
Basi c Control :
The contro l uni t ha s store d withi n it th e optimu m basi c ignitio n timin g fo r operatin g condition s base d upo n engin e spee d
and intak e ai r flo w mass . Wit h compensatin g signal s fro m sensors , th e syste m determine s optimu m ignitio n timin g an d
duratio n fo r ambien t condition s an d send s voltag e pulse s t o th e ICM .
Compensatio n of ignitio n timing :
Compensatio n Ite m
Idlin g
Compensatio n a t warm-u p
ECT compensatio n Relate
d Senso r an d Informatio n
TDC/CKP/CY P senso r
MAF senso r
ECT senso r
ECT senso r
Descriptio n
Ignition timin g i s controlle d t o th e targe t spee d
wit h compensatio n accordin g t o th e idlin g speed .
La g angl e is adjuste d accordin g t o warm-u p con -
dition s t o brin g abou t a goo d balanc e betwee n
operating performanc e an d exhaus t ga s level .
Compensatio n fo r lea d angl e a t lo w engin e
coolan t temperatur e an d la g angl e a t hig h engin e
coolan t temperature .
Control a t Start :
Ignitio n timin g is fixe d a t 5 ° BTD C fo r cranking . Th e crankin g is detecte d b y th e TD C senso r (crankin g rpm ) an d starte r signal .
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