The generator is mounted on the engine block, on its right side, in front of the right cylinder head. The Denso alternator has an output current of 85/150 A. An eight-ribbed V-ribbed belt is used to drive the alternator from the crankshaft pulley.
The alternator pulley has a freewheel that reduces the reduced moment of inertia of the engine during deceleration.
The main components of a generator are the stator, rotor, rectifier and voltage regulator. There is a three-pin connector C0053 on the generator housing:
- Pin 1 - reference voltage line to the battery through the battery electrical junction box (BJB)
- Pin 2 - PWM signal from the engine control unit (ECM) to the generator (generator control)
- Pin 3 - PWM signal from alternator to ECM (generator control)
The rotor consists of an excitation winding wound on a cast iron core and mounted on a shaft. The rotor core has protrusions on both sides, which form the north and south poles when current flows through the field winding. The rotor is placed inside the stator, and the rotor shaft is mounted on bearings, which ensure its smooth rotation and perceive significant lateral loads created by the drive belt tension.
The stator has three copper wire windings. Three stator windings connected «star» at a common point. The output current is supplied to the electrical system from the free ends of the three windings. When the rotor rotates, an alternating current appears in the winding.
The rectifier converts the alternating current generated in the stator windings into direct current (rectified) the current required to power the vehicle's electrical equipment. The rectifier is a semiconductor diode placed on a heat sink. The positive and negative sides have the same number of diodes, and an additional diode is installed in the voltage regulator to control feedback on the battery voltage signal line. The rectifier also prevents the battery from being discharged through the alternator when the alternator voltage is one voltage lower than the battery voltage.
Used to protect the battery "intellectual" regulator that controls the output voltage of the generator. At low temperatures, the recharge capacity of the battery is low, so the charging voltage should be increased as much as possible, but at high temperatures, the charging voltage should be reduced to prevent excessive gas formation in the battery and, as a result, loss of water from the electrolyte. The required output voltage of the generator is calculated by the EMS, which is responsible for controlling the generator. Conventional voltage regulators regulate according to the temperature of the alternator, which means ignoring the temperature of the battery and long periods of sub-optimal charging. The new system allows the EMS to set the required voltage based on the temperature of the battery, which is measured by various sensors, and the alternator voltage exactly matches the requirements of the battery.
To regulate the voltage in the generator, high-speed transistor switches are used. In addition, the regulator sends a pulse width modulation signal to the ECM, which is used to control the idle speed under various electrical loads.
At the initial moment, at low generator speeds, the ignition switch power circuit supplies excitation voltage to the rotor winding using brushes and slip rings. As the generator speed increases, the effect of self-excitation occurs in it.
The control signal for the battery charging warning lamp is transmitted to the EMS, and then via the CAN bus to the instrument panel.
Load control system
The load control system includes a program stored in the automatic temperature controller (ATC). For more information refer to Control Components (412-04 Control Components).
The controller is designed to maintain battery charge during abnormal use of the car. The load control system puts multimedia equipment and air suspension into economy mode, and also regulates the work of such consumers as heated seats and glass defrosters so that the battery is not discharged to a level at which the operation of the car becomes impossible. The message center screen will display 'WARNING - LOW BATTERY' (warning - low battery).
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