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Hytec Automotive ignition coils feature advanced engineering technology, high quality steel cores with optimized winding, resistance and turns ratios to deliver 10-15 percent more energy than OEM coils and are designed as a direct OEM replacement part. Specialized high temperature epoxy resists shock and vibration, while increasing thermal conductivity. These are direct plug replacements for OEM coils. They feature bodies and/or secondary towers and feature brass secondary contacts (except direct fire coil on plug applications).
An ignition coil is an induction coil in an automobile’s ignition system, which transforms the battery’s low voltage to the thousands of volts needed to create an electric spark in the spark plugs to ignite the fuel. Some coils have an internal resistor while others rely on a resistor wire or an external resistor to limit the current flowing into the coil from the car’s 12-volt supply. The wire that goes from the ignition coil to the distributor and the high voltage wires that go from the distributor to each of the spark plugs are the spark plug wires/leads.
An ignition coil consists of a laminated iron core surrounded by two coils of copper wire. Unlike a power transformer, an ignition coil has an open magnetic circuit – the iron core does not form a closed loop around the windings. The energy that is stored in the magnetic field of the core is the energy that is transferred to the spark plug. The primary winding has relatively few turns of heavy wire. The secondary winding consists of thousands of turns of smaller wire, insulated for the high voltage by enamel on the wires and layers of oiled paper insulation. The coil is usually inserted into a metal can or plastic case with insulated terminals for the high voltage and low voltage connections. When the contact breaker closes, it allows a current from the battery to build up in the primary winding of the ignition coil.
The current does not flow instantly because of the inductance of the coil. Current flowing in the coil produces a magnetic field in the core and in the air surrounding the core. The current must flow long enough to store enough energy in the field for the spark. Once the current has built up to its full level, the contact breaker opens. Since it has a capacitor connected across it, the primary winding and the capacitor form a tuned circuit, and as the stored energy oscillates between the inductor formed by the coil and the capacitor, the changing magnetic field in the core of the coil induces a much larger voltage in the secondary of the coil. The amount of energy in the spark required to ignite the air-fuel mixture varies depending on the pressure and composition of the mixture, and on the speed of the engine.
Originally, every ignition coil system required mechanical contact breaker points, and a capacitor. More recent electronic ignition systems, such as the products manufactured and supplied by Hytec Automotive, use a power transistor to provide pulses to the ignition coil. A modern passenger automobile may use one ignition coil for each engine cylinder (or pair of cylinders); eliminating fault-prone spark plug cables and a distributor to route the high voltage pulses. Ignition systems are not required for diesel engines, which rely on compression to ignite the fuel/air mixture.
In modern systems, the distributor is omitted and ignition is instead electronically controlled. Much smaller coils are used with one coil for each spark plug or one coil serving two spark plugs (for example two coils in a four-cylinder engine, or three coils in a six-cylinder engine). A large ignition coil puts out about 20 kV, and a small one such as from a lawn mower puts out about 15 kV. These coils may be remotely mounted or they may be placed on top of the spark plug. Where one coil serves two spark plugs (in two cylinders), it is through the “wasted spark” system. In this arrangement, the coil generates two sparks per cycle to both cylinders. The fuel in the cylinder that is nearing the end of its compression stroke is ignited, whereas the spark in its companion that is nearing the end of its exhaust stroke has no effect. The wasted spark system is more reliable than a single coil system with a distributor and less expensive than coil-on-plug.
