1. Field of the Invention:
The present invention relates in general to a novel ignition system, and especially such a system for use with internal combustion engines.
2. Description of the Prior Art
Conventional ignition systems for internal combustion engines have proven themselves to be reliable and adequate for many years. In recent times these systems have been upgraded by means of various electronic switching apparata. However, even with the addition of electronic apparata, the systems remain very similar in operation to the conventional electromechanical systems.
FIG. 1 is a circuit diagram illustrating a conventional ignition circuit employing an ignition transformer T having a primary winding coil PC and a secondary winding coil SC wound around a common core C. A current is introduced to the primary winding coil PC from the battery Vcc through a switch SW, such as a transistor. The energy of the ignition current supplied via switch SW is accumulated as magnetic energy and discharged through the secondary (high voltage) winding coil SC across the electrodes of spark plug SP.
Modern engines are required to meet a multitude of ever tightening standards regarding the quantity and quality of exhaust emissions. In order to meet these requirements, engine manufacturers have resorted to producing engines which operate under very lean fuel to air mixtures and engines which employ stratified charge or turbulant flow technology. Lean burning engines require increased spark duration for proper operation. Ihis is accomplished in the conventional systems by increasing the open circuit spark voltage. However, increasing the voltage results in an increase in the amplitude as well as the duration of the spark current which greatly decreases the life of the spark plugs. In turbulant flow-type systems, the flow of the charge within the individual cylinders of the engine tends to blow out or extinguish the arc occuring within the spark plug prematurely thereby decreasing the duration of the spark which is detrimental to proper ignition.
Another problem inherent in conventional designs is that they generally use a common high voltage generator in the form of a single ignition coil for all the spark plugs in the engine. The high voltage from the single coil is then distributed to the various plugs by means of a rotary high voltage switch or distributer and a system of high voltage cables. The distribution and high voltage cables are well known to be frequent sources of problems and thus are the weak links in the conventional system.