Method and device for calibrating a sensor
View Patent ↗A tank ventilation system having an intake tract, the tank ventilation system including a hydrocarbon reservoir, a sensor, and a valve. The valve and the sensor are arranged in a fluid line that couples the hydrocarbon reservoir to the intake tract. The sensor captures a hydrocarbon concentration of a fluid in the fluid line. A captured value of the hydrocarbon concentration is measured using the sensor. When the open valve, a mass flow of the fluid flowing through the fluid line into the intake tract is captured or determined. An air/fuel ratio of an air/fuel mixture fed to the internal combustion engine is determined. An estimated value of the hydrocarbon concentration in the fluid line is determined according to the mass flow of the fluid and the air/fuel ratio. The sensor is calibrated according to the captured value of the hydrocarbon concentration and the estimated value of the hydrocarbon concentration.
1. A method for calibrating a tank ventilation system sensor configured to detect a concentration of hydrocarbons in a fluid in a fluid line for an internal combustion engine with an intake section having a hydrocarbon storage device and a valve, the valve and the sensor arranged in the fluid line configured to couple the hydrocarbon storage device to the intake section, the method comprising:
detecting a value for the concentration of hydrocarbons by the sensor when the valve is open;
at least one of detecting and determining a mass flow of the fluid flowing through the fluid line into the intake section when the valve is open;
determining an air/fuel ratio of an air/fuel mixture supplied to the internal combustion engine for combustion purposes when the valve is open;
determining an estimated value for the concentration of hydrocarbons in the fluid line as a function of the mass flow of the fluid and the air/fuel ratio; and
calibrating the sensor as a function of the detected value for the concentration of hydrocarbons and the estimated value for the concentration of hydrocarbons.
2. The method as claimed in claim 1 , wherein the air/fuel ratio is determined as a function of a measurement signal from an exhaust gas probe in an exhaust gas section of the internal combustion engine.
3. The method as claimed in claim 1 , further comprising:
checking to determine whether the valve has been open at least for a prespecified time period (tmin), and if the valve has been open at least for the prespecified time period:
detecting a further detected value for the concentration of hydrocarbons by the sensor; and
calibrating the sensor as a function of the further detected value for the concentration of hydrocarbons and a prespecified reference value.
4. The method as claimed in claim 3 , wherein the prespecified reference value is characteristic of a minimum concentration of hydrocarbons in the fluid line.
5. A device for calibrating a sensor configured to detect a concentration of hydrocarbons in a fluid of a tank ventilation system arranged in an internal combustion engine with an intake section, a hydrocarbon storage device, and a valve, the valve and the sensor being arranged in the fluid line coupling the hydrocarbon storage device to the intake section, the sensor configured to:
detect a detected value for the concentration of hydrocarbons by the sensor when the valve is open;
one of detect and determine a mass flow of the fluid flowing through the fluid line into the intake section when the valve is open;
determine the air/fuel ratio from an air/fuel mixture which is supplied to the internal combustion engine for combustion purposes when the valve is open;
determine an estimated value for the concentration of hydrocarbons in the fluid line as a function of the mass flow of the fluid and the air/fuel ratio; and
calibrate the sensor as a function of the detected value for the concentration of hydrocarbons and the estimated value for the concentration of hydrocarbons.