Gas sensor, air-fuel ratio controller, and transportation apparatus

Abstract

The invention provides a gas sensor, an air-fuel ratio controller and a transportation device for simply compensating the resistance error of the heater. The gas sensor includes a gas detection section (1), a heater (2) whose electrical resistance value changes in accordance with temperature, and a control section (3) arranged to control an operation of the heater and to perform powering of the heater for heating. The control section includes a current supply section (6) to supply a current to the heater in a period during which powering of the heater for heating is stopped, a voltage detection section (7) arranged to detect an end-to-end voltage of the heater while a current is being supplied to the heater from the current supply section (6), and a current adjustment section (8) arranged to adjust the level of the current, during a cold period of the heater, which is supplied from the current supply section (6) based on an ambient temperature and the end-to-end voltage of the heater as detected by the voltage detection section (7).

Description

technical field [0001] The present invention relates to a gas sensor, and particularly to a gas sensor including a heater for raising the temperature of a gas detection unit. In addition, the present invention also relates to an air-fuel ratio control device and transportation equipment including such a gas sensor. Background technique [0002] From the standpoint of environmental problems and energy problems, it is required to improve the fuel consumption rate of internal combustion engines and to reduce the discharge amount of regulated substances (NOx, etc.) contained in exhaust gas (exhaust gas) of internal combustion engines. Therefore, in order to always burn fuel under optimum conditions, it is necessary to appropriately control the ratio of fuel to air according to the combustion state. The ratio of air to fuel is called the air-fuel ratio (A / F). In the case of using a three-way catalyst, the most suitable air-fuel ratio is the theoretical air-fuel ratio. The so-ca...

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Problems solved by technology

[0025] However, as disclosed in Patent Document 1, correcting each gas sensor will complicate the manufacturing process and increase the manufacturing cost

Also, in the case of using the technology disclosed in Patent Document 2, it is necessary to provide both means for measuring the inrush current and means for measuring the applied voltage, and in fact, the temperature of the heater rises within a short time of measuring these data, Therefore, it is difficult to correctly calculate the resistance value of the heater at room temperature

[0026] In addition, it is conceivable to install a calculation program corresponding to the resistance value of the heater (resistance value at room temperature) which is different for each gas sensor on a microcomputer, but such a method is very complicated and unrealistic.

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