841007388 - E5010 IGNITION AND RECHARGING DESCRIPTION

Description

The ignition and recharging circuit comprises the battery, starter motor and alternator.The starter motor consists of a d.c. motor supplied by the battery and an excitation electromagnet. When the ignition key is turned - or, for versions with passive entry/keyless go - the relevant knob is turned;    See E5010 STARTING AND RECHARINGas far as it will go (AVV), the mtor windings are supplied to generate the electromagnetic forces that are used to turn the engine pinion.This simultaneously activates the electromagnet that operates the mechanism that causes the pinion to mesh with the flywheel ring gear and thus turn the crankshaft.The alternator recharges the battery using the force generated by 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 rectifying diode bridge on the back of the alternator allows the alternating current to be rectified to a direct current that is sent to recharge the battery.A voltage governor, also built into the alternator, maintains the power supply at a constant voltage (14 V) regardless of the load variation range and engine speed.Recharging system efficiency is controlled by the Body Computer, which receives and measures the D+ signal from the alternator with the engine running.If a fault is detected, an appropriate message is displayed on the control panel matrix display.The Body Computer also downloads the battery voltage within a range from 18V to 6V.The information is then supplied via the CAN network to the other electronic units on the car so that certain appliances may be cut out if the battery voltage drops.Start-up may be inhibited by a battery disconnection switch in the boot. Once this is open, it cuts off the power supply to the entire car. This occurs in the case of a signal from the inertia switch or any event that could jeopordise the driver''s safety.The switch can, however, be reacivated manually by the driver.