Patent ID: 6073083
Filing Date: 2000-06-06
Classification: F02D,G01N

Abstract:
An arrangement for determining the internal resistance of a lambda probe having a positive pole and an internal resistance, the arrangement comprising:a computer having a signal input and including a computer port for outputting digital signals;a supply voltage source having a positive pole;a measurement resistor;said positive pole of said supply voltage source being connected to said positive pole of said lambda probe via said computer port and said measurement resistor;said computer having fixed pregiven values associated therewith and said fixed pregiven values including the value of said supply voltage and the value of said measurement resistor;an analog/digital converter connected forward of said signal input;said positive pole of said lambda probe being connected directly to said analog/digital converter for applying varying voltages of said lambda probe to said analog/digital converter and, after processing in said analog/digital converter, to said signal input;said computer being adapted to compute said internal resistance of said lambda probe from said varying voltages applied to said signal input and said fixed pregiven values;said computer port having a switching rate;said computer including means for periodically changing said switching rate in a pregiven time raster so that the connection of said positive pole of said supply voltage source and said lambda probe are periodically opened and closed;a series circuit including a ancillary voltage source and a ancillary resistor;said series circuit being connected in parallel with said lambda probe; and,said ancillary voltage source being a source voltage corresponding to approximately half of the Nernst voltage of said lambda probe and said ancillary resistor corresponding to approximately half the value of said internal resistance when said lambda probe is operationally warm.