Engine Electrical System

coil resistance. The ignition coil produces quite a lot
heat under normal operation and the over temperature
of ignition coil will result in such malfunctions as
increase of the ignition coil’s resistance, unstable
operation of the engine and engine stall.
Primary winding: 0.47 ohms
Secondary winding: 8 ohms
Pins:
1# pin of the primary winding is connected to the 5#
pin of ECU;
2# pin of the primary winding is connected to the 2#
pin of ECU;
3# and 4# pins are jointly connected to the positive grid
of power supply.
High voltage side: 1#, 2#, 3# and 4# pins are
connected respectively to the spark plug of the cylinder
with the same number through the distributor circuit.
Troubleshooting: Verify that there is circuit short or
circuit open in the coils.
Verify that there is electrical leakage and crack on the
shell.
Verify that the electricity for ignition is not sufficient
due to coil ageing.
※Carbon canister control valve
Function: It is used to control the purge airflow of the
carbon canister. The carbon canister control valve is
controlled by the ECU through the pulse length and
frequency (i.e. duty ratio) based on the engine load.
The excessive accumulation of fuel vapor in the carbon
canister will result in fuel spill and environment
pollution, so the function of the solenoid valve of the
carbon canister is to open the valve at an appropriate
time so that the excessive fuel vapor can enter the air
intake pipe and participate in the combustion.
Structure and working principle: The carbon canister
is comprised of magnetic coil, armature, valve and
other elements. There is a filter screen at its inlet. The
airflow passing the carbon canister control valve is not
only relative to the duty ratio of the pulse which is sent
by the ECU to the carbon canister control valve, but
also relative to the pressure difference between the exit
and inlet of the carbon canister control valve. If there is
no pulse, the carbon canister control valve is closed.
Ignition coil with double spark
Circuit diagram of the igni
tion coil
87# main relay
E-19
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