Hyundai Sonata 1991 Shop Manual page 242

Fuel Injection Control
MPI SYSTEM
Y31DCOA
The fuel injection amount is basically determined by the number of
injector activations, which corresponds to the engine rpm, and by
the injector activation time, which corresponds to the amount of
intake air during each cycle.
Injector activation occurs for each cylinder, and is one time for
each two engine rpm.
Injector Drive (Fuel Injection) Timing
Y31DDQA
1. Simultaneous injection (Non-synchronous injection)
During engine starting (cranking), there are two fuel
injections (for each engine rpm) for each of the four
cylinders.
In addition, on acceleration, fuel in an amount proportionate
to the magnitude of the acceleration during a fixed time (10
milliseconds) is injected to certain cylinders (2 cylinders)
during the intake and exhaust strokes.
No1 cyl.
l
n
TOe
signal
L________ ' - - -
Crank
angle signal
Cylinder
No.1 _-L-L-L_LJL--LL-L-L-l..
No.2 --'---'--'_-'--'---'--'-_1.-1.--l..
NO.3
_-'---'--'_-'--'--'--'-_1-1---'-
No.4 _-L-L-L_LJ_LL-L...L-.L
During engine starting
Cylinder
L....O.J
No.1 _ _
--J _
N O . 2 - - - - - l L l l J _
No.3
--.JLJ1-'__
NO.4 _-l..LJL-
.....L--.J-l..._
When acceleration
31YQ06
31-17