Resistive load measurement system
AssigneeDaimlerChrysler AG
InventorsMikhail Zarkhin, Timothy P Philippart, Roger A. Moon
Life of this patent
Estimating the term…
Abstract
An improved system for determining the value of a resistive load is provided. The system includes: a reference voltage source; a reference resistor of known value having a first and second terminal, the first terminal connected to the reference voltage source and the second terminal connected to the resistive load; and a software program stored in a control unit connected to the first and second terminal, the control unit operative to read a value of the reference voltage source and a voltage at the second terminal of the predetermined reference resistor and to calculate the value of the resistive load as a function of the readings of the reference voltage source and the second terminal voltages.
Claims19
An apparatus for determining a value of a resistive load comprising:
- a reference voltage source;
- a reference resistor having a known value and having a first and second terminal, the first terminal coupled to the reference voltage source and the second terminal coupled to the resistive load;
- a first switch operative to connect the resistive load with the reference resistor to create a voltage divider;
- and
- a control unit coupled to the first and second terminal, the control unit including a software program operative to read a value of the reference voltage source and a voltage at the second terminal and to calculate the value of the resistive load as a function of the readings of the reference voltage source, the second terminal voltage, and the known value of the reference resistor.
A method for determining a value of a resistive load comprising the steps of:
- providing a reference voltage source and a predetermined reference resistor having a known value and having a first and second terminal, connecting the first terminal to the reference voltage source and connecting the second terminal to the resistive load;
- providing a switch operative to connect the resistive load to the reference resistor to create a voltage divider;
- providing a software program stored in a control unit and connecting the control unit to the first and second terminal;
- reading a value of the reference voltage source and a voltage at the second terminal of the predetermined reference resistor;
- and
- calculating with the software program the value of the resistive load as a function of the readings of the reference voltage source, the second terminal voltages, and the known value of the reference resistor.
An oxygen sensor temperature measurement system comprising:
- an engine controller having an oxygen sensor and an oxygen sensor heater operable to heat the oxygen sensor;
- a resistance measuring circuit having a reference voltage source and a reference resistor having a known value;
- a switch coupled to the oxygen sensor heater, the switch operative to connect the oxygen sensor heater to the reference resistor to create a voltage divider;
- a driver operative to provide a load current to the oxygen sensor heater;
- a control unit operable to disable the driver and thereafter to measure a resistance of the oxygen sensor heater using the resistance measuring circuit, and to determine a temperature of the oxygen sensor based on the resistance of the oxygen sensor heater.
Dependencies are inferred from the claim text.