7. System of start and charging
The system of ignition makes ignition of fuel mix in engine cylinders at some point depending on turns of the engine and loading. On cars many various types of systems of ignition are established.
The system of ignition eats from onboard network of the car. In the ignition coil tension of onboard network of the car will be transformed to high voltage. High voltage is used for formation of a spark between electrodes of spark plugs in engine cylinders in a compression step. The chain of low voltage, or primary chain, consists of an electrical wiring which connects the accumulator, the ignition lock, primary winding of the coil of ignition, the breaker and the condenser. The chain of high voltage, or a secondary chain, consists of a high-voltage winding of the coil of ignition, the central high-voltage wire, the distributor of ignition, a rotor of the distributor, high-voltage wires of spark plugs and spark plugs.
The coil of ignition will transform faltering current of low voltage (+12 V) to a high-tension current for breakdown of an air gap between electrodes of spark plugs. The coil of ignition represents the transformer with the opened magnetic conductor which consists of the internal core and an external ring magnetic conductor. The secondary winding having a large number of rounds is reeled up around the core. Primary winding with smaller number of rounds is reeled up over secondary.
The system of ignition works as follows. When giving tension on primary winding of the coil of ignition in the coil of ignition there is a magnetic field. For inclusion and switching off of tension given to primary winding of the coil of ignition the electronic block is used.
At switching off of tension on primary winding of the coil of ignition power failure of magnetic field in a secondary winding generates the high voltage which via the distributor of ignition moves to a candle of the corresponding cylinder. Then tension moves again to primary winding of the coil of ignition therefore magnetic field increases and the cycle is repeated for giving of high voltage to the following spark plug.
The corner of an advancing of ignition is set by the distributor and corrected centrifugal and vacuum by regulators. The centrifugal regulator consists of two small weights which at increase in turns of the engine under the influence of centrifugal force disperse from a distributor shaft. Dispersing, small weights turn a cogwheel concerning a distributor shaft, and thus the ignition moment depending on engine turns is corrected. The size of a divergence of small weights is defined by effort of returnable springs.
The vacuum regulator fixed on the ignition distributor case consists of the diaphragm block. To one party of a diaphragm depression from the carburetor moves through a hose. Other party of a diaphragm is connected by draft with the ignition distributor. Under the influence of depression the diaphragm is bent and through draft turns a basic plate against the direction of rotation of a shaft of the distributor, and as a result of it the ignition advancing corner depending on engine loading is corrected.
When working on electric system not to damage semiconductor devices (diodes and transistors), it is necessary to fulfill the following requirements:
– in operating time of the engine do not disconnect the accumulator, the generator of alternating current or any electric sockets;
– when carrying out any works remove the negative plug from the accumulator;
– when carrying out electrowelding works on the car switch-off the generator of alternating current and the electronic control device;
– do not allow operation of the engine with the generator disconnected from electric system;
– do not check operability of the generator, closing its output contacts on weight.