08-17-2017, 12:15 AM
electronic ignition system technical seminar
Before electronic ignition systems were developed ignition control was undertaken using mechanical distributors. The distributor directed the output from a single high-tension (HT) ignition coil to the relevant spark plug.Control over the timing of ignition was done through a cam operated contact breaker, centrifugal weights, springs and cams, with load mapping done through using a vacuum advance unit.Distributor based systems are prone to mechanical wear, insulation break down and contact failure. To keep the ignition timing correct these systems required a periodic tune up to keep them working correctly.Modern electronic ignition systems do not require a distributor. A single small HT coil is used for each spark plug and the igniter operates each coil separately in the correct sequence.Engine position information is provided by engine position sensors and a timing disks that are accurately attached to one or two of the main engine shafts, such as the camshaft. The firing sequence and variable spark advance is computed accurately from the pattern of teeth or pegs on the timing disk. If load mapping is required, this can be achieved by adding a manifold pressure sensor or a throttle angle potentiometer to the system. A variety of extra features are available on such systems, which can be accessed and adjusted by a PC.Electronic Ignition systems provide extremely accurate spark timings, leading to improved combustion and emissions control. As there is no mechanical contact there is no wear therefore the accuracy is maintained. These reasons are why electronic ignition is used as standard throughout the industry.An ignition system is a system for igniting a fuel-air mixture. Ignition systems are well known in the field of internal combustion engines such as those used in petrol (gasoline) engines used to power the majority of motor vehicles, but they are also used in many other applications such as in oil-fired and gas-fired boilers, rocket engines, etc.The first ignition system to use an electric spark was probably Alessandro Volta's toy electric pistol from the 1780s. Virtually all petrol engines today use an electric spark for ignition.Diesel engines rely on air compression for ignition, but usually also have glowplugs that preheat the combustion chamber to allow starting of the engine in cold weather. Other engines may use a flame, or a heated tube, for ignition.