The non-contact ignition system is a constructive continuation of the contact-transistor ignition system. In this ignition system, the contact chopper is replaced by a proximity sensor. A non-contact ignition system is standardly installed on a number of models of domestic cars, and can also be installed independently instead of a contact ignition system.
The use of a contactless ignition system allows to increase engine power, reduce fuel consumption and emissions of harmful substances due to a higher discharge voltage (30000V) and, accordingly, better combustion of the fuel-air mixture.
Structurally, the contactless system combines a number of elements, including a power source, an ignition switch, a pulse sensor, a transistor switch, an ignition coil, a distributor, and, of course, spark plugs. The distributor is connected to the spark plugs and the ignition coil using high voltage wires.
The pulse sensor is designed to create low-voltage electrical pulses. There are pulse sensors of the following types: Hall, inductive and optical.
The greatest application in a contactless ignition system has been found by a pulse sensor using the Hall effect (the occurrence of transverse voltage in a conductor plate with current under the influence of a magnetic field). The Hall sensor consists of a permanent magnet, a semiconductor wafer with a microcircuit, and a steel screen with slots (shutter).
A slot in the steel shield passes a magnetic field and voltage arises in the semiconductor wafer. The steel screen does not allow a magnetic field to pass through, and voltage does not occur on the semiconductor wafer. Alternating slots in the steel screen creates low voltage pulses.
The pulse sensor is structurally integrated with the distributor and form one device – the sensor-distributor. The distribution sensor is similar in appearance to the distribution switch and has a similar drive from the engine crankshaft.
The transistor switch is used to interrupt the current in the primary circuit of the ignition coil in accordance with the signals of the pulse sensor. The current is interrupted by unlocking and locking the output transistor.