312001045 - E5010 IGNITION AND RECHARGING - DESCRIPTION

DESCRIPTION

The ignition and recharging circuit comprises the battery, starter motor and alternator.The battery (12V) is low maintenance type.The starter motor consists of a d.c. motor supplied by the battery and an excitation electromagnet.When the ignition key is turned as far as it will go (AVV), the motor windings are supplied to generate the electromagnetic forces that are used to turn the starter motor pinion. This simultaneously activates the electromagnet that operates the mechanism, which causes the pinion to mesh with the flywheel ring gear and thus turn the crankshaft.The alternator recharges the battery during normal engine rotation.The alternator shaft (rotor) is turned by the crankshaft via a belt. When supplied by an excitation current, the rotor generates a magnetic field that sets up an alternating current in the fixed winding (stator).A diode rectifier bridge, located at the back of the alternator, transforms the alternating current into a direct current: this recharges the battery.A voltage regulator built into the alternator maintains the power supply at a constant voltage (around 14 V) throughout all load variation and engine speed ranges.The engine control unit and Body Computer monitor the efficiency of the recharging system:

• the engine management control unit receives the voltage signal coming from the D+ terminal of the alternator with the engine moving;
• the Body Computer checks the efficiency of the alternator recharging system by detecting two parameters: the D+ signal and the engine rpm signal both received via the CAN from the engine management control unit.

The Body Computer also acquires the battery voltage value in the range 6 - 18 V.If the voltage is too low or the current generation system is faulty, the warning light in the instrument panel is operated.