 I am Mr. N. R. Thambake, Assistant Professor, Department of Mechanical Engineering, Valchan Institute of Technology, Swalapur. Today, we are going to discuss automobile lighting and ignition system. Learning outcome. At the end of this session, students will be able to explain automobile lighting and ignition system. In this particular session, we are going to discuss introduction of lighting system, lighting circuit diagram and how it works. Then, different switch positions of lighting system, that is parking position, headlamp position, off position. Then next, we are going to discuss introduction of ignition system, then ignition circuit diagram and its working. Dear students, please think what is the purpose of lighting system in an automobile. Now, let us see. Lights are used in modern motors vehicle for a wide variety of purposes. That are, headlights are necessary to illuminate the highways sufficiently to permit safe night driving. These are usually provided with two or more beams, one of which provides maximum illumination for night driving. And the other is so designed as to permit the flexion to the ground to the side of the road to minimize glare when passing other cars on the road. When a third beam is used, it is usually of low intensity for city driving. Tail lights are used to illuminate the rear of the car, including the license plate, so that both car and license plate can be seen by drivers of other vehicles. Tail lights usually incorporate stop lights, which flash red whenever the brakes are applied. In addition to the headlights, low intensity parking lights usually are provided in the front of the car, either as separate units or as a part of the headlamps. The lighting system also includes lights inside the body to illuminate the compartments in which the passenger rides, special lamps to light the instrument panel, and sometimes special lights to illuminate the keyhole for the ignition key. Map lights, trunk compartment lights, radio dial lights and caulk lights are also provided on same car, some cars. Flashing signals on the front and rear to indicate to other drivers the direction in which the car is about to be turned or standard equipment. In addition, one or more special lights designed as signal to the driver are incorporated. Such special lights include a red signal light to indicate the stop light beams of the headlamps are burning. This is the lighting circuit diagram in which the right front lamp, left front lamp, right turn indicator, left turn indicator, flasher unit, switch, force flasher, right rear lamp and left rear lamps are shown. Then how this particular lighting circuit is working? It is a single circuit employing one wire and count. Current is applied to the system from the battery or generated at 6 to 8 volt or 12 to 15 volt. So, table switches and fuses or circuit breakers to protect the system from overload are also included in the system. The circuit begins at the battery and passes through the emitter or charge indicator at fuse or circuit breaker before it reaches any switch. The stop light branch is controlled by the stop light switch in the brake system so that when the brakes are applied the switch is closed. The down light is controlled either by a hand operated pillar switch or by an automatic door switch that completes the circuit when the door is opened. All the other lights are controlled by the light switch on the instrument panel. This switch generally has three positions. One is parking position, second one is head lamp position and third one is off position. We discuss in detail these three positions. Parking position. What is happening in this? In the parking position it completes the circuit to the parking lights, tail lights, license plate, light and instrument lights. Head lamp position. In this particular position, in the head lamp position, the light switch sends current to the head lamp as well as to the tail light, license plate light and instrument light. The head lamp circuit generally contains a foot operated dimmer switch which determines whether the current goes to the upper or lower beam elements. In the upper beam position, it also sends current to a smaller red indicator lamp on the instrument panel. Now we will see ignition system. The coil is the compartment that produces this high voltage. It is an electromagnetic device that converts the low tension current from the battery to high tension current. Each time the distributor contact breaker points open. The distributor unit consists of a metal bowl containing a central shaft which is usually driven directly by the crankshaft or sometimes by the crankshaft. The bowl houses the contact breaker points, rotor arms and a driver for alternating the ignition timing. It also carries the distributor cap. This is what the ignition system circuit diagram is there in which the switch is located. There is a battery, then there is a coil, high tension circuit is there which is indicated with the blue wire. And condenser unit is there, distributor is there, electrodes are present, then the rotor arm is there. The plug terminals are also there. So how it works exactly? The distributor cap is made of non-conductive plastic and the current is fed to its central electrode by high tension lead for the center of the coil. So inside the cap there are more electrodes often called segments to which the spark plug leads are connected one per cylinder. The rotor arm is fitted on top of the central shaft and connects to the central electrode by means of a metal spring or spring loaded brush in the top of the distributor cap. The current enters the cap through the central electrode, passes through the center of the rotor arm through the brush and it distributed to each plug as the rotor arm revolves. As the rotor arm approaches a segment, the contact breaker point opens and high tension current passes through the rotor arm to the appropriate spark plug lead. The contact breaker points are mounted inside the distributor, they act as a switch in synchronization with the engine. That cuts off the reconnects, cuts off and reconnects the 12-volt low tension circuit to the coil. The points are opened by the cams on the center shaft and are closed again by a spring arm on the moving contact. With the points closed, low tension current flows from the battery to the primary windings in the coil and then to earth through the points. When the points open, the magnetic field in the primary winding collapses and high tension current is induced in the secondary winding. This current is transferred to the spark plug through the distributor cap. On a four cylinder engine, there are four cams. With each full rotation of the shaft, the points open four times. Six cylinder engines have six cams and six electrodes in the cap. The position of the points and the distributor's body in relation to the central shaft can be adjusted manually. This alters the timing of the spark to obtain an exact setting. Further changes occur automatically as the engine speed varies according to the throttle opening. So in some modern ignition systems, microelectronics ensure the optimum ignition timing for all engine speed and engine load conditions. The spark plugs are screwed into the combustion chambers in the cylinder head. High tension current passes from each segment on the distributor cap. Down the plug leads to the plug caps. It then passes down the central electrode when it is insulated along its length to the nose for the plug. So these are the references. So that are the levels of understanding. Then the propulsion will be there by automobile engineering by standard publisher. Automobile mechanics by N.K. Giri. Automobile electrical equipment by P.S. Kauley. Then K. Newton and W. Sheets. T.K. Garrett Motor Vehicle elsewhere publication. William H. Krause Automotive Mechanics by Tata Madhprabhu publishing house. Thank you. Thank you.