Safety measures when servicing vehicles equipped with an additional passive safety system (SRS)
The SRS system includes the following components: SRS ECM, SRS warning lamp, airbag modules, clock spring and connecting wires.
Improper service or repair of any component of the SRS system (as well as a component associated with the SRS system) may result in injury or death to operating personnel (as a result of unauthorized deployment of an airbag), as well as the driver and front passenger (as a result of the inoperability of the SRS system after unskilled service or repair).
Maintenance or repair of any component of the SRS system (or related component) must only be carried out by an authorized Mitsubishi dealer.
Consumers are connected to a positive power source by a wire, and to a negative one - through the car body («mass»). This method reduces the number of wires and simplifies installation.
Charging system
The charging system uses the power from the alternator to keep the battery charged regardless of changes in electrical load.
The alternating magnetic field arising during the rotation of the generator rotor induces in the stator winding a variable in magnitude and direction of the EMF (AC voltage).
Passing through the rectifier diodes, the alternating voltage is converted to direct. The average value of the generator output voltage varies slightly depending on the load.
When the ignition key is turned to position «ON» («ON») current passes through the rotor winding and the initial magnetization of the winding occurs (generator excitation).
When, after starting the engine, voltage is generated on the stator winding, the excitation winding (rotor) powered by the output current of the stator winding, rectified by three rectifier diodes. With an increase in the excitation current, the output voltage of the generator increases, and with a decrease in the excitation current, it drops.
When the battery voltage reaches the set value of 14.4V (conclusion «S» generator), the excitation current is switched off. When the battery voltage drops below the set value, the voltage regulator, by controlling the field winding current, maintains the generator output voltage at a constant level. In addition, when the excitation current is constant, the generator output voltage increases with increasing engine speed.
Engine start system
When the ignition key is turned to position «START» («STARTER») current passes through the retracting winding of the traction relay of the starter, moving the armature of the traction relay.
Traction relay armature moves drive lever (fork), which, in turn, engages the drive gear with the flywheel ring gear. At the same time, the movement of the armature of the traction relay closes the contacts «IN» And «M».
As a result, the current begins to pass through the windings of the starter armature (as well as the holding winding of the traction relay), thereby turning on the starter motor. When the ignition key is returned to the position after starting the engine «ON» («ON»), the starter freewheel disengages the drive gear from the flywheel ring gear.
To prevent the starter from being carried by the engine, a freewheel clutch is installed between the starter drive gear and the armature.
Ignition system
The ignition system ignites the air-fuel mixture in the engine cylinders at a certain moment, depending on the engine speed and load. Various types of ignition systems are installed on cars.
The ignition system is powered by the car's on-board network. In the ignition coil, the voltage of the car's on-board network is converted into high voltage. High voltage is used to create a spark between the electrodes of the spark plugs in the engine's cylinders during the compression stroke. The low voltage circuit or primary circuit consists of electrical wiring that connects the battery, the ignition switch, the primary winding of the ignition coil and the electronic ignition unit. The high voltage circuit or secondary circuit consists of the ignition coil high voltage winding, high voltage center wire, ignition distributor, distributor rotor, spark plug high voltage wires and spark plugs.
Ignition coil converts low voltage intermittent current (+12 V) into a high voltage current to breakdown the air gap between the electrodes of the spark plugs. The ignition coil is a transformer with an open magnetic circuit, which consists of an inner core and an outer ring magnetic circuit. The secondary winding, which has a large number of turns, is wound around the core. Primary winding (with fewer turns) wound over the secondary.
The ignition system works as follows. When voltage is applied to the primary winding of the ignition coil, a magnetic field is generated in it. An electronic unit is used to turn on and off the voltage supplied to the primary winding of the ignition coil.
When the voltage is turned off on the primary winding of the ignition coil, the voltage drop of the magnetic field in the secondary winding generates a high voltage, which is supplied through the ignition distributor to the spark plug of the corresponding cylinder. The voltage is then applied again to the primary winding of the ignition coil, causing the magnetic field to increase and the cycle repeats to apply high voltage to the next spark plug.
Diesel engine preheating system
Glow plugs reduce the time required to start the engine in low ambient temperatures.
The ECM monitors both the amount of time the current heats the glow plugs after the ignition is switched on and the amount of time that the glow plug warning light stays on, according to the engine coolant temperature.
Precautions when working with the electrical equipment system
When working on the electrical system, in order not to damage the semiconductor devices (diodes and transistors), the following requirements must be met:
- while the engine is running, do not disconnect the battery, alternator or any electrical connectors;
- when carrying out any work, remove the wire from the negative terminal of the battery;
- when carrying out electric welding work on a car, turn off the alternator and electronic control device;
- do not allow the engine to run with the generator disconnected from the electrical system;
- do not test the generator's performance by shorting its output contacts to «mass».