1975 Datsun 280z FSM - Spooled up Racing

Engine Fuel
i
W. FUEL INJECTION
PULSE
1; Generation of injection
pulse in control unit
Figure EF-5 shows the control unit
block diagram. The function of major
elements in the control unit is
described as follows:
(1) ICj
Upon receiving revolution trigger
signal ® from the ignition coil negative
terminal, the IC. carries out wave
form shaping (2) and frequency conversion
(3) operation and issues injection
timing signal for each rotation of
the engine.
(2) IC 2
Upon receiving the timing signal
(engine rpm signal) from the IC, and
the signal (intake air flow signal) from
the air flow meter, the ICL computes
the base pulse Tp utilizing the chargedischarge
characteristics of condenser.
The IC- also carries out correction to
the "start" increment using the signal
from the starter.
(3) IC 3
In the IC 3 increments are added to
the base pulse Tp determined in the
IC 2 depending on the signals sent from
the sensors. The input for the multivibrator
(D includes the base pulse
(Tp), water temperature signal, intake
air temperature signal, throttle valve
switch signal and starting switch signal,
and the output is a corrected pulse
(Tq) of the base pulse (Tp). The
multi-vibrator (6) issues the voltage
correction pulse (Ts) which corrects
delay in the mechanical response of
the injector. The voltage correction
pulse (Ts) is determined by the battery
voltage signal. In the logic circuit of
the IC 3 , the base pulse (Tp), correction
pulse (Tq) and voltage correction
pulse (Ts) are combined to form a
summation pulse (Tg = Tp + Tq + Ts),
which in turn is sent to the power
amplifier in the next stage.
(4) Power amplifier
The power amplifier amplifies the
summation pulse (Tg) generated in the
IC 3 , and sends it to the injector. The
actual open-valve time period of the
injector is "Tg - Ts = Tp + Tq", since
the delay in mechanical response (Ts)
is inherent in the injector operation.
This actual open-valve time period is
called the "effective injection pulse
(Te = Tp + Tq)".
EF-8