Automotive ignition system in the distributor center high-voltage wire and high-voltage branch line of the circuit direction is how?

Automotive ignition system troubleshooting Qiu Yali (Hunan Institute of Transportation Technology, Changsha, Hunan 410004) Abstract: Explained the modern automobile three typical ignition system composition, working principle and troubleshooting methods. Keywords: automobile; ignition system; structural characteristics; working principle; fault diagnosis CCTI: U464 Literature ID: B 1 Traditional contact ignition system 1.1 Structural characteristics The composition of this ignition system is shown in Figure 1. It consists of battery, ignition coil, distributor (disconnector and distributor), ignition switch and spark plug. The distributor shaft is driven by the engine camshaft, and the number of cam angles of the breaker cam is equal to the number of engine cylinders. When working, the ignition coil primary current is controlled by the contact of the breaker, and the centrifugal and vacuum adjusting devices installed inside and outside the distributor shell control the ignition advance angle according to the approximate adjustment method. The representative models are Jiefang and Dongfeng. Fig. 1 Composition of traditional contact ignition system 1.2 Basic working principle When the engine rotates, the camshaft of the breaker in the distributor rotates with it, and the breaker contacts close and open alternately. When the ignition switch is turned on, the contact is closed, then the ignition coil primary winding current through, and gradually increase. When the contact is open, the secondary winding produces 15~25 kV high voltage, the distributor according to the engine ignition order will be distributed to the high voltage to each cylinder spark plug, produce electric spark. 1.3 Troubleshooting 1) First of all, determine whether the fault is in the low-voltage circuit or in the high-voltage circuit. Turn on the ignition switch, start the engine, observe the ammeter, such as the ammeter pointer indicates a discharge of 3 ~ 5 A and intermittently swing back to zero, indicating that the low-voltage circuit is good, the fault in the high-voltage circuit. If the ammeter indicates zero or indicates a discharge of 3 ~ 5 A, and does not swing back to zero, or indicates a high-current discharge, indicating that the primary circuit is faulty. Can also be based on the jumping fire situation to determine where the fault lies. Method is: pull down the distributor cover on the center of the high-pressure line, so that the end of the line from the engine body 6 ~ 8 mm, start the engine, observe the high-pressure jump-start situation. If you can not jump the fire, said the fault in the low-voltage circuit or ignition coil; if you can jump the fire, said the low-voltage circuit and ignition coil is normal, the fault is in the distributor or spark plugs. 2) high-voltage circuit troubleshooting. Unplug the distributor cover on the center of the high-pressure line test fire normal, can be installed back to the high-pressure line, and then pulled down from the spark plug cylinder high-pressure line, so that the distance between the cylinder block 6 ~ 8 mm, start the engine, observe the jumping fire situation. If the spark is strong, indicating that the distributor and sub high-pressure line is normal, the fault in the spark plug; if no spark, indicating that the fault is in the ignition head, distributor cover or sub high-pressure line. 3) Low-voltage circuit troubleshooting. Low-voltage circuits are mainly disconnected or short-circuit two. Eliminate broken circuit fault, can be used to check the voltage point by point method, such as checking the ignition coil to the breakers of the contacts without voltage, that is, the ignition coil primary winding to the ammeter between the broken circuit fault; if the voltage, that is, the broken circuit fault occurs in the ignition coil to the breakers between. Elimination of short-circuit faults, can be based on the ammeter reading roughly determine the location of the short circuit, and then determine the method of disconnection. Such as turning on the ignition switch, the ammeter indicates a high current discharge, indicating that the ammeter to the additional resistance between the lap fault; such as starting the ammeter indicates a high current discharge, indicating that the starter to the additional resistance between the wire has a lap fault; such as starting, the ammeter indicates that the 5 A current discharge and the pointer does not oscillate, it is indicated that the disconnecting contact can not be opened, the capacitor breaks through the arm of the movable contact arm lap fault. Date of receipt: 2004-06-07Author's introduction: Qiu Yali (1964-), female, associate professor, engaged in automotive theory research and teaching. Ignition system and electronic ignition system. The primary current of semiconductor-assisted ignition system is carried out by a breaker contact controlling the conduction and cutoff of semiconductor tertiary tubes. Because the contact is sensitive to pollution, especially when the distributor is rotating at high speed, due to the role of mechanical inertia, the contact will jump vibration, so that the secondary voltage is reduced; at the same time, the wear and tear of the cam and contact arm rubber wood block will affect the normal operation of the ignition system. Modern cars use less. Electronic ignition system contains a signal generator and ignition advance device distributor, ignition controller, ignition coil and spark plugs, etc., as shown in Figure 2. The signal generator installed in the distributor and the ignition Figure 2 Electronic Ignition System Composition Diagram of the end of the high-power transistors in the controller is equivalent to the traditional ignition system in the role of the distributor contacts. The ignition coil is a special high-energy ignition coil, the resistance and inductance of the primary winding is small, the low-voltage current is large, and the ignition energy is high. Its representative models such as Santana, Audi, Jetta, etc. 2.2 Basic working principle of the signal generator rotates, the surrounding magnetic field changes, the sensor generates a voltage signal, which is amplified and shaped by the ignition controller to control the conduction and cut-off of the final high-power transistor, so that the primary current in the ignition coil changes, and high voltage is induced in the secondary winding. Ignition controller in the closing angle (refers to the final stage of high-power transistor conduction during the angle of the distributor turned. The larger the angle, the longer the transistor conduction time, the greater the primary current) control, constant current control (high-energy ignition coil is used to reduce the resistance value of the primary winding to increase the primary current, the current is large, easy to burn out the end of the high-power transistor, it must be limited) performance so that the primary winding current, whether in the engine at high speeds or low speeds, are a certain value of the secondary voltage is also a certain value, which improves the performance of the ignition. 2.3 Troubleshooting 1) First of all, determine whether the fault is in the ignition control circuit or in the high-voltage circuit. Unplug the distributor cover on the center of the high-voltage wire, so that the end of the line from the engine body 6 ~ 8 mm, start the engine, observe the high-voltage jump-start situation. If you can jump fire