Electromagnetic ignition--an ignition system producing a large size and intense capacitive and inductive spark with an intense electromagnetic field feeding the spark
First Claim
1. An electrical ignition system comprising a high voltage ignition coil capable of producing a voltage Vs greater than 20 Kilovolts for igniting air-fuel mixtures contained in a combustion chamber of an internal combustion engine, the chamber being defined by at least an outer fixed chamber member and an inner chamber member, at least one spark plug mounted on said outer chamber member to produce an ignition spark inside said combustion chamber, a secondary winding of said coil in combination with said plug and interconnecting cable comprising secondary circuit capacitance Cs to ground, and means defining a spark plug firing end including a high voltage igniting tip constructed and arranged to electrically break down the air-fuel mixture gap between said igniting tip and said inner or outer combustion chamber member under conditions enabling an effective breakdown over a length of at least 0.1 inch (0.25 cm) to produce a spark of at least 0.1 inch (0.25 cm) under at least one condition of operation of said engine, so as to provide under all normal operating conditions of said engine a high breakdown voltage and corresponding high secondary capacitive stored energy just prior to breakdown given by 1/2*Cs*Vs**2 which is greater than five millijoules for delivery of said energy immediately after breakdown of said gap.
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Accused Products
Abstract
An Electromagnetic Ignition system suitable for adaptation to standard automobile engines including diesel engines, which has been improved by means of a high efficiency RF capacitive spark plug with a projecting antenna tip used for forming very large spark gaps to the plug shell and piston face as well as for coupling high electric fields to the local initial flame plasma, preferably used in combination with shielded high voltage cable including series inductive choke elements and a Capacitive Discharge ignition system incorporating an input capacitor, a SCR switch, an ignition coil with an optimized high current and high output voltage, and preferably a synchronous DC-DC power converter providing "boost power" during ignition so that substantial capacitive, inductive, and electromagnetic energy is supplied to the air-fuel mixture. Preferably the coil has a turns ratio of 50 with the input capacitor having a capacitance between 5 and 10 microfarads and a 400 volts rating. Large output capacitance is provided naturally by existing coil and shielded cable capacitance, supplemented with large plug capacitance of 50 to 250 picofarads, which are charged up to between 15 and 30 Kilovolts prior to breakdown of the wide variable spark gap producing: high frequency capacitive sparks, large inductive spark of several amps; and high pulsed local EM electric field strength of thousands of volts/cm providing a practical, highly efficient ignition system capable of igniting very lean air-fuel mixtures for reducing exhaust emissions and increased engine efficiency.
220 Citations
58 Claims
- 1. An electrical ignition system comprising a high voltage ignition coil capable of producing a voltage Vs greater than 20 Kilovolts for igniting air-fuel mixtures contained in a combustion chamber of an internal combustion engine, the chamber being defined by at least an outer fixed chamber member and an inner chamber member, at least one spark plug mounted on said outer chamber member to produce an ignition spark inside said combustion chamber, a secondary winding of said coil in combination with said plug and interconnecting cable comprising secondary circuit capacitance Cs to ground, and means defining a spark plug firing end including a high voltage igniting tip constructed and arranged to electrically break down the air-fuel mixture gap between said igniting tip and said inner or outer combustion chamber member under conditions enabling an effective breakdown over a length of at least 0.1 inch (0.25 cm) to produce a spark of at least 0.1 inch (0.25 cm) under at least one condition of operation of said engine, so as to provide under all normal operating conditions of said engine a high breakdown voltage and corresponding high secondary capacitive stored energy just prior to breakdown given by 1/2*Cs*Vs**2 which is greater than five millijoules for delivery of said energy immediately after breakdown of said gap.
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31. Combustion ignition system comprising in combination:
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(a) means defining a spark plug for mounting in a combustion chamber and for acting as a first anchor of a sparking discharge extending therefrom to a spaced portion of a combustion chamber wall, which effectively provides a ground return to an ignition circuit through said chamber wall, (b) means defining said ignition circuit, said circuit being connected to said spark plug for effecting at least one space firing period having an initial VHF to UHF current oscillation lasting for at least about one microsecond, whereby an electrical self resonance is induced in the combustion chamber by the circulation of said VHF-UHF current along the chamber wall to establish an oscillating EM field which enhances said spark discharge and flame kernel, while each such spark firing period further includes high capacitive and inductive spark energy transfer from the circuit to the spark. - View Dependent Claims (32, 33, 34, 35)
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36. Internal combustion engine apparatus comprising:
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(a) a combustion chamber formed of a cylinder; (b) a piston disposed in said cylinder for compressing air-fuel mixture by moving in successive cycles to and from a TDC position defining a minimum combustion volume;
the improvement comprising a combustion ignition system comprising at least one high voltage high capacitance electrode mounted in a central zone of the top of said cylinder and constructed and arranged as part of a CD ignition circuit to effect oscillations of sparking to the face of said piston during a spark firing period to generate essentially entirely internally to said combustion chamber and said high capacitance electrode circuit a VHF to UHF self resonant electrical oscillation and wherein the capacitance of high capacitance electrode is at least 20 picofarads and said spark firing period includes inductive component of at least two oscillations during a single engine cycle. - View Dependent Claims (37, 38, 39, 56)
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- 40. In a combustion apparatus comprising an enclosed combustion volume, a spark ignition and fuel and air feeding means, and an improved ignition system comprising means for generating an initial capacitive high frequency spark discharge of high initial breakdown voltage within the range of 3 MHz to 600 MHz oscillating internally within said combustion volume at an initial field strength in excess of 500 volts/cm/atmosphere for a duration of at least of the order of magnitude of one microsecond, through ignition circuit controlled conversion from a power supply of essentially DC frequency, i.e. frequency less than 1 MHz, the ignition system being constructed and arranged to repetitively render such spark discharges in repetitive combustion cycles.
- 45. In an electrical ignition system used for igniting air-fuel mixtures contained in a combustion chamber of an IC engine including at least one spark plug with a central high voltage conductor and an outer ground conductor containing a dielectric ceramic material interposed between said central conductor and said outer ground conductor, the improvement comprising means for providing maximum plug capacitance and minimum resistance to EM current in said spark plug by plating with high electrical conductivity material the ceramic surfaces of the portion of the said ceramic section interposed between said central and outer conductors.
- 50. In an ignition system containing at least one spark plug, each such spark plug comprising means defining a conductive shell and a protruding central antenna conductor tip extending substantially beyond the spark plug shell of greater than 0.070" (0.175 cm) diameter and surrounded along part of its length with insulator of thickness about equal to tip diameter, the foregoing structure further defining a base gap "go" of at least 0.04" (0.1 cm), wherein said spark plug is mountable in a combustion chamber of an IC engine to define therein an EM Control Volume characterized by formation of both ignition spark and long duration high electric fields of strengths of at least 5000 volts/cm over at least a one cubic cm volume around said antenna tip.
- 54. In an IC engine including at least one combustion chamber to which is mounted at least one spark plug and wherein each of said spark plugs are connected to at least one ignition coil, which ignition coil is part of a CD circuit with total secondary circuit high voltage capacitance Cs, the improvements comprising spark plug firing ends designed to provide a minimum spark breakdown voltage Vsm under normal operating engine conditions such that at least 5 millijoules are stored in Cs prior to breakdown and choke inductor interposed between high voltage terminal of said coil and high voltage terminal of said plug to control and tune discharge of secondary capacitances making up Cs and wherein inductance of said choke inductor is between 5 and 400 microhenries.
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57. An ignition system for cyclically firing internal combustion engine with a varying combustion volume comprising
(a) means for generating sequentially within said volume in each cycle of firing the following: -
(i) rapid, large gap electromagnetic energy current pulses of magnitude greater than 100 amps and delivering approximately 50 KWatts to the large gap at an operating frequency between 50 and 500 MHz, (ii) less rapid capacitive energy derived ignition pulses of magnitude greater than 20 amps and delivering approximately 10 KWatts to the large gap at an operating frequency between 1 and 50 MHz, (iii) much less rapid ignition pulses of approximately 4 amps peak current and delivering approximately 1 KWatt to the large gap at a frequency of approximately 10 KHz, (b) antenna means for coupling said electromagnetic current pulses and high electric field pulses within an EM Control Volume of at least one cubic cm; (c) means defining a large gap spark anchor of 0.16" to 0.32" (0.4 to 0.8 cm) relative to said antenna means contained within said EM Control Volume. - View Dependent Claims (58)
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Specification