Device for controllably heating oxygen sensor
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsYoshiki Chujo, Hiroshi Noguchi
Life of this patent
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Abstract
Pulse current having a certain cycle is supplied to an electric heater in an oxygen sensor for exhaust gas. Duty ratio of this pulse current is controlled in relation to the amplitude of voltage and current applied to the heater to thereby maintain power consumption of the heater per unit time at a constant one. Also this duty may be corrected on the basis of parameters for running an internal combustion engine.
Claims22
A device for controllably heating an oxygen sensor provided in an exhaust pipe of an internal combustion engine comprising;
- a means for supplying heat to said oxygen sensor;
- means for generating from said oxygen sensor an output proportional to the oxygen concentration in the exhaust gas from said internal combustion engine and the air/fuel ratio which is controlled in the lean mixture regions by means of an oxygen sensor;
- means for providing pulse current to the heater wherein said heater is controlled in relation to the heater voltage and the heater current and wherein the current in the form of a pulse has a specific cycle which is supplied to said heater and the ratio of the pulse width to the cycle is controlled on the basis of the product of the signal related to the heater voltage and the signal related to the heater current, such that the power consumption of the heater per unit time is maintained within a predetermined range.
A device for controllably heating an oxygen sensor provided in an exhaust pipes of an internal combustion engine comprising;
- means for providing heat by way of electricity provided to said sensor;
- means for providing an output from said oxygen sensor which generates an output proportional to the oxygen concentration in the exhaust gas and air/fuel ratio which is controlled in the lean mixture region by means of said oxygen sensor;
- means for providing a pulse current to the heater such that the pulse current is controlled in relation to the heater voltage and the heater current and wherein the current has a specified cycle which is supplied to said heater and the ratio of the pulse width of said cycle is controlled on the basis of the product signal related to the heater voltage and the signal related to the heater current and signals related to parameters for running the engine such that the power consumption of said heater per unit time remains within a predetermined range.
Dependencies are inferred from the claim text.