US 2011/0253114 A1 · Method for Igniting a Fuel/Air Mixture of a Combustion Chamber, in Particular in an Internal Combustion Engine, by Creating a Corona Discharge

Abstract

The invention relates to a method for igniting a fuel/air mixture in a cyclically operating internal combustion engine comprising one or more combustion chambers (1) which are delimited by walls (2, 3, 4) that are at ground potential, using an igniter, wherein an electrical transformer (12) having a baseline impedance (ZBaseline) that is characteristic for the selected ignition system on the primary side thereof is used to excite an electric oscillating circuit (7), which is connected to a secondary winding (17) of the transformer (12) and in which an ignition electrode (5), which extends through one of the walls (2, 3, 4) delimiting the combustion chamber (1) in an electrically insulated manner, constitutes a capacitance together with the walls (2, 3, 4) of the combustion chamber (1) that are at ground potential, and wherein the excitation of the oscillating circuit (7) is controlled such that a corona discharge (22) igniting the fuel/air mixture is created in the combustion chamber (1) at the ignition electrode (5). According to the invention, before every moment of ignition of the internal combustion engine, the electric voltage (U) applied at a primary winding (14, 15) of the transformer (12)—referred to hereinbelow as primary voltage—is increased incrementally, wherein the increments by which the primary voltage (U) is increased are selected such that the intensity of the electric current (I) flowing in the primary winding (14, 15)—referred to hereinbelow as primary current—increases incrementally due to the stepwise increase in the applied primary voltage (U) by amounts that become smaller as the impedance at the input of the transformer (12) increases, and move toward a specifiable minimum upon approaching a voltage at which a voltage breakdown—referred to hereinbelow as breakdown voltage UD—occurs in the oscillating circuit (7).

Claims22

Dependent claims

A method for igniting a fuel/air mixture in a cyclically operating internal combustion engine comprising one or more combustion chambers which are delimited by walls that are at ground potential, using an igniter,

wherein an electrical transformer having a baseline impedance that is characteristic for the selected ignition system on the primary side thereof is used to excite an electric oscillating circuit, which is connected to a secondary winding of the transformer and in which an ignition electrode, which extends through one of the walls delimiting the combustion chamber in an electrically insulated manner, constitutes a capacitance together with the walls of the combustion chamber that are at ground potential,
and wherein the excitation of the oscillating circuit is controlled such that a corona discharge igniting the fuel/air mixture is created in the combustion chamber at the ignition electrode, wherein before every moment of ignition of the internal combustion engine, the electric voltage applied at a primary winding of the transformer—referred to hereinbelow as primary voltage—is increased incrementally, wherein the increments by which the primary voltage is increased are selected such that the intensity of the electric current flowing in the primary winding—referred to hereinbelow as primary current—increases incrementally due to the stepwise increase in the applied primary voltage by amounts that become smaller as the impedance at the input point of the transformer increases, and moves toward a specifiable minimum upon approaching a voltage at which a voltage breakdown—referred to hereinbelow as breakdown voltage UD—occurs in the oscillating circuit.

Dependencies are inferred from the claim text.

Method for Igniting a Fuel/Air Mixture of a Combustion Chamber, in Particular in an Internal Combustion Engine, by Creating a Corona Discharge

Life of this patent

Method for Igniting a Fuel/Air Mixture of a Combustion Chamber, in Particular in an Internal Combustion Engine, by Creating a Corona Discharge

Life of this patent

Abstract

Claims22