Patent Application
20150109084
There are no previously filed, nor currently any co-pending applications, anywhere in the world.
1. Field of the Invention
The present invention relates to internal combustion engine ignition systems for generating a combustion spark for igniting the air-fuel mixture within the engine's cylinder and, more particularly, to an improved ignition system and ignition coil for generating and delivering a spark signal with greater efficiency.
2. Description of the Related Art
Ignition systems are well known in the field of internal combustion engines, and are used for igniting the fuel-air mixture within each cylinder. This creates combustion to drive the power stroke of the cycle. Prior generations of four-stroke engines used a mechanically timed electrical ignition system in which a distributor, containing a rotating cam (or rotor) driven by the engine's drive, directed the generated spark to each individual cylinder in a timely manner. An external ignition coil created high voltage, low current energy by converting it from a low voltage, high current battery. Wires direct the current from the coil to the distributor, and from the distributor to the spark plugs.
The power from the battery (which is charged by the car's electrical system using an alternator) is transformed by the coil for eventually transmission to the spark plugs. In these mechanically timed systems, the engine operates contact breaker points, which interrupt the current to an induction coil, in order to control the spark timing.
Various disadvantages exist in these mechanically timed ignition systems. These include, for example, the timing breaker points being subject to mechanical wear, as well as oxidation and burning at the contact surfaces from the constant sparking. Further, mechanical systems require regular adjustment to compensate for such wear, as well as to correct variation in the spark timing that can result from such mechanical variations over time. Such limitations result in obtaining only a reasonable service life of the system, and only if the power of the spark and ultimate engine speed are limited.
Current four-stroke engines utilize electronic ignition (EI) systems to solve such problems. In these systems, the control of the high primary current is accomplished through solid state switching, and contact breaker points are similarly replaced by an angular sensor of some kind, i.e., either optical, where a vaned rotor breaks a light beam, or more a Hall effect sensor, which responds to a rotating magnet mounted on the distributor shaft. The sensor output is shaped and processed by suitable circuitry within an “electronics box”, and then used to trigger a switching device such as a thyristor, which switches a large current through the coil.
In spite of improvements achieved by electronic ignition systems, they still utilize an otherwise conventional ignition coil (in series with a capacitor or condenser). This is, in essence, a type of electrical transformer in which low voltage, high amperage current is transformed to high voltage, low amperage current. The ignition coil consists of two transformer windings, the primary and secondary windings, sharing a common magnetic core. An alternating current in the primary induces alternating magnetic field in the coil's core. Because the ignition coil's secondary has far more windings than the primary, the coil is a step-up transformer which induces a much higher voltage across the secondary windings. For an ignition coil, one end of the windings of both the primary and secondary are connected together. This common point is connected to the battery (usually through a current-limiting ballast resistor). The other end of the primary is in electrical communication with the spark plugs, through a digital electronic ignition modules in EI systems, or through the distributor cap and rotor in mechanical systems.
Some more modern ignition designs are using an Engine Management Systems (EMS) to further control the spark timing and delivery, or an even more integrated Engine Control Unit (ECU) that controls both spark timing and delivery, as well as other engine functions, such as air/fuel mixture, idle speed, valve timing, torque, and the like. However, even these EMS and ECU arrangements retain a standard ignition coil of an otherwise conventional design. Some systems may dispense with a distributor altogether and have individual coils mounted directly atop each spark plug, which eliminates the need for both a distributor and high-tension leads. However, in these systems, multiple ignition coils are then deployed.
In all these systems, the ignition systems produces and delivers a high-voltage spark from the ignition coil, which was transformed from a low voltage battery supply source. 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. Under laboratory conditions as little as 1 millijoule is required in each spark, but practical coils must deliver much more energy than this to allow for higher pressure, rich or lean mixtures, losses in ignition wiring, and plug fouling and leakage. When gas velocity is high in the spark gap, the arc between the terminals is blown away from the terminals, making the arc longer and requiring more energy in each spark. Between 30 and 70 millijoules are delivered in each spark.
The extremely high voltage causes a spark to form across the gap of the spark plug is delivered from the coil's secondary (typically 20,000 to 50,000 volts). This, in turn, ignites the compressed air-fuel mixture within the engine. It is the creation of this spark which consumes the energy that was stored in the ignition coil's magnetic field. In high performance engines with eight or more cylinders or in engines that operate at high r.p.m., both a higher rate of spark and a higher spark energy are required. Further, any efficiencies or losses created within the coil windings themselves can also tax or limit the coil's secondary output.
Consequently, improved efficiencies in the design and resulting operation of the ignition coil(s) can result in either improved ignition energy creation performance, or improved efficiency in the conversion of batter energy.
An otherwise conventional 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 where 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. When demanded, current does not flow instantly because of the inductance of the coil. Because conventional wire windings have a generally round cross sectional area, the efficiency of packing these windings is limited, i.e. the given coil wire winding density is limited by the geometry and spacing of the packed windings. Since the inductance of the primary and secondary the inductance of the coil is limited by the coil winding density, an increasingly dense primary or secondary winding configuration can cause any induced current to flow longer and store more energy in the core magnetic field for the eventually delivered spark.
Consequently, a need exists for and a benefit can be obtained by providing an improved ignition system ignition coil for generating and delivering a spark signal with greater efficiency.
It is therefore an object of the present invention to provide an improved automobile ignition system for an internal combustion engine.
It is a feature of the present invention to provide an improved ignition system and ignition coil for generating and delivering a spark signal with greater efficiency.
Briefly described according to the preferred embodiment of the present invention, an improved automobile ignition system is providing having an improved ignition coil configuration for generating and delivering a spark signal with greater efficiency. The improved ignition coil is formed around a magnetic core for formation of a magnetic field which is subsequently amplified as soon as voltage is applied. The core may be a solid iron core, or of a laminated configuration in which several thin ferromagnetic sheets are wound up to form a central cylindrical element. Circumscribing the core is a secondary coil, and circumscribing the secondary coil is a primary coil. The primary coil is formed of a linear length of a copper wire having a generally rectangular cross sectional area. The wire forming the primary coil is thicker and has a generally larger cross sectional area in comparison with that of the secondary coil. The secondary coil is similarly formed of a linear length of a copper wire having a generally rectangular cross sectional area. The wire forming the secondary coil is thinner and has a generally smaller cross sectional area in comparison with that of the primary coil. The primary coil itself further has a shorter overall length than the secondary coil. Consequently, the primary coil has significantly fewer windings that the secondary coil. In order to prevent electric discharge and spark-overs in the interior of the coil or outward, the windings of the primary and secondary coils must be insulated.
In otherwise conventional ignition coils, a high-quality winding of the coil wires is attempted in which the wires are precisely arranged and densely arranged, above one another, so that there is a minimized spacing between them. In the present invention, given the generally rectangular cross sectional area of the coil windings (both primary and secondary), the intra-wire spacing can be further reduces.
Finally, the cylindrical coil wound core is contained within a plastic or metallic housing that is filled with a with an oil, asphalt or an epoxy potting resin to prevent moisture intrusion, eliminate air bubbles and provide inslulatin of the created thermal load.
It is an overall objective of the present inventive ignition coil to provide an automobile ignition system with the generation of a greater spark signal, or for delivering a spark signal with greater battery efficiency.
It is thus an object of the present invention to provide a high frequency coil and/or high current capacity coil.
It is a further object of the present invention to provide the delivery of a spark that has enough voltage and energy to ensure combustion of the fuel mixture.
It is yet a further object of the present invention to be able to reliably accomplish these goals throughout a variety of rpm, load, temperatures and conditions.
Further features of the invention will become apparent in the course of the following description.
The advantages and features of the present invention will become better understood with reference to the following more detailed description and claims taken in conjunction with the accompanying drawings, in which like elements are identified with like symbols, and in which:
The best mode for carrying out the invention is presented in terms of its preferred embodiment, herein depicted within the Figures wherein like reference numerals indicate the same parts throughout the several views.
Referring now to
As shown in
It should be apparent to a person having ordinary skill in the relevant art, in light of the teachings anticipated by the present invention, that an improved coil configuration according to the present invention may be applicable in conjunction with any of the presently available variations of automobile ignition systems currently available, whether mechanically timed or electronically timed, utilizing block coil designs or coil on plug designs, or others.
With an arrangement that includes a distributor 20 and block coils 18, the ignition voltage travels over the ignition cables 22 to the spark plugs 16. In an alternate design (for example, see
Referring in conjunction with
The primary coil 46 is further of a shorter overall length than the secondary coil. 44 Consequently, the primary coil 46 has significantly fewer windings that the secondary coil 44. In order to prevent electric discharge and spark-overs in the interior of the coil or outward, the windings of the primary coils 46 and secondary coils 44 are insulated 52. Finally, a housing 54 contains the entire assembly to form a moisture resistant, insulated assembly.
In otherwise conventional ignition coils, a high-quality winding of the coil wires is attempted in which the wires are precisely positioned and densely arranged, above one another, so that there is a minimized spacing between them. Referring now in conjunction with
Referring now to
The improved coil 70 is formed around a magnetic core 72. The core 72 is preferably formed of a laminated configuration in which several thin ferromagnetic sheets 74 are wound up to form the central cylindrical element 72. Circumscribing the core 72 is a secondary coil 76, and circumscribing the secondary coil 76 is a primary coil 78. As shown in greater detail in conjunction with
The primary coil 78 is further of a shorter overall length than the secondary coil 76. Consequently, the primary coil 78 has significantly fewer windings that the secondary coil 76. In order to prevent electric discharge and spark-overs in the interior of the coil or outward, the windings of the primary coils 78 and secondary coils 72 are insulated with a could compound or epoxy resin 84. Finally, a housing 86, formed of a plastic, or preferably metallic material, contains the entire assembly to form a moisture resistant, insulated assembly.
The regular configuration of the windings 80, 82 of the present invention are provided arrange adjacent wires to be packed far tighter, and with less intra winding spaces, than is otherwise available in standard wiring having generally circular cross sectional areas. In such a coil arrangement, there are generally four factors that affect the resistance of the wire conductor. These are:
In light of the present teachings, is should now become apparent to those having sufficient skill in the relevant art, that the benefits and improvements of the present invention may be achieved utilizing coil winding wires having other polygonal shapes, other than circular, that further decrease the overall intra-wiring area in relation to the overall conductor cross sectional area. By way of example, and not as a limitation,
In operation, the present invention can provide an improved automobile ignition system for use with the improved coil configuration. As shown in
The foregoing descriptions of the specific embodiments are presented for purposes of illustration and description. They are not intended to be exhaustive nor to limit the invention to the precise forms disclosed and, obviously, many modifications and variations are possible in light of the above teaching. The embodiments are chosen and described in order to best explain principles of the invention and its practical application, and to thereby enable others skilled in the art to best utilize the invention and its various embodiments with various modifications as are suited to the particular use contemplated. It is intended that a scope of the invention be broadly defined by the Specification and Drawings appended hereto and to their equivalents; hence, the scope of the invention is to be limited only by the following claims.
