System and method for generating and sustaining a corona electric discharge for igniting a combustible gaseous mixture

A system for igniting a fuel-air mixture in a combustion chamber having combustion chamber walls, the system comprising:

• an electrode inside of the combustion chamber;
• an electric circuit delivering radio frequency electric power at a frequency of between 30,000 and 3,000,000 hertz to the electrode;
• a ground formed at least in part by the combustion chamber walls;
• and
• means for controlling an output of the electric circuit to the electrode so that complete dielectric breakdown does not occur and so that an electric arc is not struck in the combustion chamber;
• wherein a radio frequency voltage differential formed between the electrode and the ground produces a radio frequency electric field therebetween which causes a fuel-air mixture to ionize resulting in combustion of the fuel-air mixture;
• and
• wherein the electric circuit comprises a low voltage circuit and a high voltage circuit, the low voltage circuit driving the high voltage circuit through a radio frequency step-up transformer, the high voltage circuit having a resonant frequency and the low voltage circuit driving the high voltage circuit at or near its resonant frequency, the electrode being connected to an output of the high voltage circuit;
• and
• wherein the means for controlling the output of the electric circuit to the electrode measures an actual impedance in the electrical circuit and compares the actual impedance to a setpoint impedance.

A method of igniting a combustible gaseous mixture in a combustion chamber comprising:

• discharging electric energy through an electrode with a corona discharge into a combustion chamber filled with combustible gaseous mixture;
• causing the combustible gaseous mixture to ionize due to the corona discharge to a sufficient level of ionization that the ionized combustible gaseous mixture commences a self-sustaining combustion reaction that combusts the combustible gaseous mixture in the combustion chamber;
• measuring an actual impedance of a circuit that provides power to the electrode;
• comparing the actual impedance with a setpoint impedance;
• and
• controlling a rate of discharge of electric energy through the electrode to cause the actual impedance to substantially match the setpoint impedance such that a plasma is not created and an electric arc is not struck in the combustion chamber.

A method of igniting a combustible gaseous mixture in a combustion chamber comprising the steps of:

• providing radio frequency power to an electrode such that a corona discharge is generated between the electrode and the combustion chamber;
• measuring a voltage and a current of a power source which powers the electrode;
• and
• controlling a power level provided to the electrode based on the measured voltage and current to sustain the corona discharge between the electrode and the combustion chamber, wherein the corona discharge provides sufficient energy to ignite the combustible gaseous mixture in the combustion chamber.

A method of igniting a combustible gaseous mixture in a combustion chamber comprising the steps of:

• providing radio frequency power to an electrode such that a corona discharge is generated between the electrode and the combustion chamber;
• measuring a voltage and a current of a power source which powers the electrode;
• and
• controlling a power level provided to the electrode based on the measured voltage and current to sustain the corona discharge between the electrode and the combustion chamber, wherein the corona discharge provides sufficient energy to ignite the combustible gaseous mixture in the combustion chamber;
• wherein the power level provided to the electrode is controlled to prevent a plasma arc from forming between the electrode and the combustion chamber.

A method of igniting a combustible gaseous mixture in a combustion chamber comprising the steps of:

• providing radio frequency power to an electrode such that a corona discharge is generated between the electrode and the combustion chamber;
• measuring a voltage and a current of a power source which powers the electrode;
• controlling a power level provided to the electrode based on the measured voltage and current to sustain the corona discharge between the electrode and the combustion chamber, wherein the corona discharge provides sufficient energy to ignite the combustible gaseous mixture in the combustion chamber;
• calculating an actual impedance from the measured voltage and current;
• comparing the actual impedance to an impedance setpoint;
• and
• controlling the power level provided to the electrode to cause the actual impedance to substantially match the impedance setpoint.

An engine comprising:

• a combustion chamber for containing a combustible gaseous mixture;
• an electrode;
• a power source which powers the electrode;
• a current sensor which measures a current in the power source;
• a voltage sensor which measures a voltage in the power source;
• and
• means for controlling a power level provided to the electrode based on the measured voltage and current to sustain a corona discharge between the electrode and the combustion chamber, wherein the corona discharge provides sufficient energy to ignite the combustible gaseous mixture.

An engine comprising:

• a combustion chamber for containing a combustible gaseous mixture;
• an electrode;
• a power source which powers the electrode;
• a current sensor which measures a current in the power source;
• a voltage sensor which measures a voltage in the power source;
• and
• means for controlling a power level provided to the electrode based on the measured voltage and current to sustain a corona discharge between the electrode and the combustion chamber, wherein the corona discharge provides sufficient energy to ignite the combustible gaseous mixture, wherein the means for controlling a power level prevents the formation of a plasma and an electric arc in the combustion chamber.