Gated ionization current supply voltage

An internal combustion engine comprising:

• a block including a combustion chamber;
• an ion sensor fluidly coupled with the combustion chamber;
• a crankshaft;
• a high voltage supply output electrically coupled to the ion sensor;
• and
• a controller comprising control logic configured to:
• supply a low voltage to the ion sensor during a combustion cycle of the internal combustion engine, wherein the low voltage is configured to prevent premature ignition of fuel in the combustion chamber;
• after supply of the low voltage, supply a high voltage to the ion sensor during the combustion cycle at a first time based on a crankshaft angle of the crankshaft of the internal combustion engine, wherein the high voltage exceeds the low voltage and is configured to increase an ion sensor current above a current threshold;
• and
• discontinue supply of the high voltage to the ion sensor at a second time based on the crankshaft angle during the combustion cycle;
• wherein the high voltage is proportional to one of an exhaust gas recirculation percentage or an air-fuel ratio of an air-fuel mixture in the combustion chamber.

A controller for an internal combustion engine, the controller comprising control logic structured to:

• supply a low voltage to an ion sensor during a combustion cycle of the internal combustion engine, wherein the low voltage is configured to prevent premature ignition of fuel in a combustion chamber;
• after supply of the low voltage, supply a high voltage to the ion sensor during the combustion cycle at a first time based on a crankshaft angle of a crankshaft of the internal combustion engine, wherein the high voltage exceeds the low voltage and is configured to increase an ion sensor current above a current threshold;
• and
• discontinue supply of the high voltage to the ion sensor at a second time based on the crankshaft angle during the combustion cycle;
• wherein the high voltage is proportional to one of an exhaust gas recirculation percentage or an air-fuel ratio of an air-fuel mixture in the combustion chamber.

A method of operating an internal combustion engine comprising a combustion chamber and an ion sensor fluidly coupled with the combustion chamber, the method comprising:

• supplying a high voltage to the ion sensor during a combustion cycle at a first time based on a crankshaft angle of a crankshaft of the internal combustion engine, wherein the high voltage is greater than 400 volts and is configured to generate an ion sensor current above a current threshold;
• and
• discontinuing supply of the high voltage to the ion sensor at a second time based on the crankshaft angle during the combustion cycle;
• wherein the first time and the second time define a high voltage window, and supplying the high voltage comprises supplying the high voltage during the high voltage window and not at other times during the combustion cycle;
• and
• wherein a duration of the high voltage window is between 10 and 40 degrees.

A method of operating an internal combustion engine comprising a combustion chamber and an ion sensor fluidly coupled with the combustion chamber, the method comprising:

• supplying a high voltage to the ion sensor during a combustion cycle at a first time based on a crankshaft angle of a crankshaft of the internal combustion engine, wherein the high voltage is greater than 400 volts and is configured to generate an ion sensor current above a current threshold;
• and
• discontinuing supply of the high voltage to the ion sensor at a second time based on the crankshaft angle during the combustion cycle;
• wherein the internal combustion engine is a compression ignition engine, and wherein the first time occurs at or after a start of ignition in the combustion chamber.

A method of operating an internal combustion engine comprising a combustion chamber and an ion sensor fluidly coupled with the combustion chamber, the method comprising:

• supplying a high voltage to the ion sensor during a combustion cycle at a first time based on a crankshaft angle of a crankshaft of the internal combustion engine, wherein the high voltage is greater than 400 volts and is configured to generate an ion sensor current above a current threshold;
• and
• discontinuing supply of the high voltage to the ion sensor at a second time based on the crankshaft angle during the combustion cycle;
• wherein the high voltage is configured to maintain the ion sensor current flowing through the ion sensor above the current threshold;
• and
• wherein the current threshold is greater than 100 microamperes.