In the electronic ignition system, which is one of the most important
components of a modern car, high voltage current is created and distributed
thanks to electronic devices. The electronic system has many clear advantages
and also makes it easier to start the engine in winter.
An electronic ignition system is a system in
which high voltage current is generated and distributed by electronic devices.
The electronic ignition system of modern cars, which controls the injection and
ignition systems, is an important component of the engine management system. On
cars of the latest models, the same system is responsible for the operation of
the intake and exhaust systems, as well as the operation of the cooling system.
Today, the market offers such ignition systems
as Bosch, Simos, Motronic, Magneti-Marelli, each of which is structurally
different from the others. In general, we can say that electronic ignition
systems are divided into direct ignition systems and distributor systems. The
latter operate from a mechanical distributor , which supplies high voltage current to a
specific spark plug. If we are talking about direct ignition systems, then
the current is supplied to them directly from the ignition coil.
Electronic ignition system device
Any electronic ignition system includes
components such as a power supply, input sensors and ignition switch , electronic control unit, igniter, coil and spark plugs . Some systems also have high voltage wires .
Input sensors are responsible for recording
the current engine operating parameters, converting them into electrical
signals. The range of sensors may vary slightly depending on the car model.
The electronic control unit processes the
signals coming from the input sensors, influencing, in turn, the igniter. The
igniter, which is based on a transistor, is a kind of electronic board that
turns the ignition on/off. When the transistor is open, current flows through
the primary winding of the coil. If the transistor is closed, it is cut off,
and the current is induced through the secondary winding of the coil.
The electronic ignition system can have
different coils: one common, individual or dual. Common coils are used in
systems that have a distributor. Individual coils are installed directly on the
spark plug, so high-voltage wires are not used in such a system.
Twin coils are used in direct ignition
systems. If the engine has four cylinders, one coil is installed on the 1st and
4th, as well as on the 2nd and 3rd cylinders, each of which is responsible for
creating current at two terminals, which is why ignition sparks appear
simultaneously in two cylinders In one, the fuel-air mixture ignites, in the
other, ignition occurs idle.
- controller;
- electromagnetic valve
EPHH;
- screw sensor;
- coolant temperature
sensor;
- inductive reference and
angular pulse sensors;
- ignition coils;
- spark plugs;
- ignition switch;
- battery;
- fuse and relay block
Principle of operation
The electronic control unit responds to sensor
signals, calculating the optimal parameters for the operation of the system.
First of all, the control unit acts on the igniter, which supplies voltage
to the ignition coil , in the primary winding of which
current begins to flow.
When the voltage is interrupted, a current is
induced in the secondary winding of the coil. Directly from the coil or through
high-voltage wires, the current is sent to a specific spark plug, in which a
spark is formed that ignites the fuel-air mixture.
If the speed of rotation of the crankshaft
changes, the sensor responsible for its rotation frequency, as well as the
sensor that regulates the position of the camshaft, send signals directly to
the electronic control unit, which changes the ignition timing.
If the engine load increases, the ignition
timing is controlled by an air flow sensor . The knock sensor
provides important additional information about the ignition and combustion of
the fuel-air mixture.
Advantages of electronic ignition systems
Electronic ignition systems have many
advantages:
- possibility of use on any type of carburetor engines.
- increase in secondary voltage by 1.3-1.5 times, which can be 20-30 kV in any engine operating mode.
- long service life of the breaker contacts, which can reach 150 thousand km or more.
- an increased gap is observed between the electrodes of the spark plugs , reaching 1-1.2 mm.
- in winter, the engine starts easier.
- saving time when carrying out preventive and adjustment work.
Among the disadvantages of electronic ignition
systems, the complexity and high cost of the system primarily stand out, but
all the disadvantages are compensated by the above advantages.