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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-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 needle gets sucked in. The needle gets pulled 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 injector relay to the injector and up to
the engine-ECU. Engine-ECU turns ON its power transistor and prepares the injector’s
earth 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-ECU changes current
direction according to the Open/Close direction and also changes current to the motor coil to
control the 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 <MPI> - Evaporative Emission
Control System .
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The inlet oil feeder control valve is installed on the inlet side of the cylinder head.
Receiving the duty signal from the engine-ECU, the inlet oil feeder control valve operates the
spool valve position and divides the oil pressure from the cylinder block into the advanced
chamber and the retarded chamber of the V.V.T. sprocket as well as continually changes the inlet
camshaft phase. The spring makes spool valve stop at the position where the inlet camshaft is
at the most retarded angle when the engine is stopped. The engine-ECU operates the spool valve position
by increasing and decreasing ON duty ratio of the inlet oil feeder control valve and allows
the inlet camshaft to be at the target phase angle. When the duty ratio increases, the V.V.T.
sprocket makes phase of inlet camshaft advanced angle side. When the duty ratio degreases, the
V.V.T. sprocket makes phase of inlet camshaft retarded angle side. When the medium duty ratio,
at which the spool valve is at the medium position, is achieved, all the oil passages are closed.
This allows the phase angle to be kept constant. The engine-ECU changes and controls the duty
ratio in accordance with the engine operation to get the optimum phase angle.
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Engine-ECU uses ON/OFF of alternator G terminal to control alternator output voltage.
When the power transistor in the engine-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-ECU turns OFF, output voltage gets adjusted to about 14.4 V. When alternator output voltage
is about 14.4 V, alternator outputs current to produce electricity. In case electric load is
generated suddenly, engine-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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