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An injector is an injection nozzle with the electromagnetic valve that injects fuel based
on the injection signal sent by engine-A/T-ECU. 1 injector is installed in the inlet manifold
of each cylinder and fixed to the delivery pipe. When electricity flows through the solenoid
coil, the plunger gets sucked in. The ball valve is integrated with the plunger, and gets pulled
together with the plunger till the fully open position so that the injection hole is fully open
and the fuel gets injected.
Voltage from the battery gets applied from the engine control relay to the injector and
up to the engine-A/T-ECU. Engine-A/T-ECU turns ON its power transistor and prepares the injector’s
ground circuit. Thus, current flows through the injector while power transistor is ON and the
injector injects fuel.
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A throttle valve control servo is installed in throttle body. The throttle valve control
servo performs the Open/Close of the throttle valve through the reduction gear. Engine-A/T-ECU
changes current direction according to the Open/Close direction and also changes current to
the motor coil in order to the control throttle valve control servo.
Throttle valve control servo is composed of a good response, low energy, and small DC
motor with brush and can generate rotation force corresponding to the current applied on the
coil.When there is no current passing through the throttle valve control servo, the throttle
valve remains at a prescribed opening angle. So, even if current stops because of a fault in the
system a minimum level of running remains possible.
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Refer to GROUP 16 -
Ignition System -
Ignition Coil  .
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Refer to GROUP 17 -
Emission Control <6G7> -
Exhaust Gas Recirculation
(EGR) System .
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Refer to GROUP 17 -
Emission Control <6G7> -
Evaporative Emission
Control System .
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A variable induction control solenoid valve is installed on the inlet manifold plenum.
The variable induction control solenoid valve is an ON/OFF control type solenoid valve. When
current is not passing through the coil, nipple A is kept air-tight and air passes through nipple
B and the filter. When current is passed through the coil, air is unable to pass through the
filter and it passes through nipple A and nipple B. Engine-A/T-ECU changes the ON/OFF of solenoid
valve according to the engine’s operating conditions to change between negative pressure
in vacuum tank and atmospheric pressure and performs the Open/Close of the vacuum actuator.
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An oil feeder control valve is installed on the cylinder head. The oil feeder control
valve is a duty control type solenoid valve and is used in oil pressure control for cam change.
When no current is passing through the oil feeder control valve’s coil (duty: 0 %), port
B gets closed and the oil pressure path between port A and port C connects. Oil that had been
acting on the cam change control piston is expelled from port C via port A. Thus, the low-speed
cam drives the inlet valve. When current is passed through the coil (duty: 100 %) and
the spool moves, port A gets closed and port B and port C get connected. At this time the oil
pressure-fed from the oil pump passes from port B via port C and acts on the cam change control
piston. Thus, high-speed cam drives the inlet valve. The engine-A/T-ECU changes the duty ratio
and switches the cam in accordance with the engine operation.
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Engine-A/T-ECU uses ON/OFF of alternator G terminal to control alternator output voltage.
When the power transistor in the engine-A/T-ECU turns ON, output voltage gets adjusted to about
12.8 V. When alternator output voltage drops to 12.8 V it becomes lower than voltage of the
charged battery and almost no current is output from the alternator. When the power transistor
in the engine-A/T-ECU turns OFF, output voltage gets adjusted to about 14.7 V. When alternator
output voltage is about 14.7 V, alternator outputs voltage current to produce electricity. In
case electric load is generated suddenly, engine-A/T-ECU controls alternator G terminal’s
On-duty to limit the sudden increase in alternator load due to generation and thus prevents
change in idle speed.
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