Description
The present invention relates to a sensor control device and a sensor control system, wherein the sensor control device and the sensor control system measure, for example, a concentration of a specific component in an object measurement gas such as an aerated mixture of an internal combustion engine, and are suitable for use in an oxygen sensor The output signal is compensated.
Background of the invention
In recent internal combustion engines, in order to improve fuel economy and reduce harmful substances contained in exhaust gas, control of an air-fuel ratio as a ratio of fuel to intake air is generally performed, particularly for fuel versus intake air. Control of the ratio of oxygen contained in the medium. When this control is performed, it is necessary to measure the volume of the intake air. For example, a method of using an air mass flow sensor for measuring the volume of intake air is known. The air mass flow sensor is used in an internal combustion engine equipped with an intake throttle valve and can be used to measure an in-cylinder intake air volume that changes according to an operating state.
On the other hand, an intake throttle valve is not provided in a diesel engine, a direct injection gasoline engine, or the like, and the intake air volume in the cylinder is substantially constant. Further, in a diesel engine having an exhaust gas recirculation device (hereinafter referred to as "EGR device") for recirculating a part of the burned exhaust gas into the intake air, the ratio of oxygen contained in the intake air It is changed by the amount of exhaust gas for recirculation (hereinafter referred to as "EGR amount"). In other words, the amount of oxygen in the cylinder changes.
In this case, it is difficult to precisely control the air-fuel ratio using only the above-described air mass flow sensor. That is, in the control of the air-fuel ratio using only the air mass flow sensor, the in-cylinder oxygen ingress is calculated on the assumption that the ratio of oxygen contained in the intake air is the same as the ratio of oxygen contained in the air, for example. the amount. Since the ratio of oxygen contained in the intake air is changed in the internal combustion engine equipped with the EGR device, it is impossible to accurately calculate the in-cylinder oxygen intake amount.
Summary of the invention
It is known that in the case of using an oxygen sensor as described above, it is necessary to compensate for variations in output values due to, for example, deterioration of the oxygen sensor. In particular, in the case where the oxygen sensor is disposed only in the intake system, high oxygen sensor accuracy is required. Further, the necessity of compensation is improved as compared with the case where the oxygen sensor is disposed in the intake system and the non-intake system. For this reason, the technique disclosed in JP-A-H02-221647 also compensates for the output value of the oxygen sensor after the internal combustion engine is stopped.
However, power is always consumed in the case of compensating for the output value of the oxygen sensor, and in the case of the vehicle, the power is supplied from the installed battery. When the power of the battery is insufficient in the case where the compensation is performed after the internal combustion engine is stopped as disclosed in JP-A-H02-221647, there is a fear that the compensation cannot be performed in an accurate state. More specifically, there may occur a case where the heater of the oxygen sensor cannot be sufficiently driven, or a case where the temperature of the sensing element cannot be accurately controlled. Further, even in the case of performing compensation, there is a fear that the battery is easily exhausted due to the consumption of power of the battery.
The drawing shows a schematic diagram of the overall structure of a sensor control system according to a first embodiment of the present invention.
SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a sensor control apparatus and a sensor control system capable of suppressing a heater equipped with a heater while suppressing power consumption of a battery installed together with an internal combustion engine The measurement accuracy of the oxygen sensor is deteriorated.
In the first aspect (1), the above object of the present invention has been achieved by providing the following: a sensor control device for connecting to an oxygen sensor, the oxygen sensor comprising: a sensing element for measuring the progress of the internal combustion engine An oxygen concentration in the gas; and a heater for heating the sensing element, the sensor control device comprising: a detecting unit configured to detect a output corresponding to the oxygen concentration output from the sensing element An output signal; and a calculation unit for calculating a compensation coefficient of an output signal used for calculating the oxygen concentration, wherein the internal combustion engine is in operation and is capable of estimating an oxygen concentration in the intake air In the case of a specific operational state, the calculation unit collects compensation information used in calculating the compensation coefficient.
According to the sensor control device of the present invention, in the case where the internal combustion engine is in operation and in a specific operational state capable of estimating the oxygen concentration in the intake air, collection of compensation information for calculating the compensation coefficient is performed. Therefore, the compensation coefficient for compensating the output signal of the sensing element based on the compensation information can be calculated and updated. Thus, even in the correspondence relationship between the value of the output signal of the sensing element and the oxygen concentration in the intake air, due to, for example, deterioration of the sensing element, the compensation coefficient calculated in the calculation unit can be used. The output signal is compensated to eliminate the deviation of the corresponding correspondence. Further, in the present invention, as described above, in the case where the internal combustion engine is in operation, the calculation unit collects compensation information used to calculate the compensation coefficient. The timing at which the calculation unit calculates and updates the compensation coefficient of the output signal may be the time when the internal combustion engine is in operation and may be the time when the internal combustion engine is in the non-operating state. There is no specific limit to this moment.
Further, in the sensor control device of the present invention, since the calculation unit collects the above-described compensation information in the case where the internal combustion engine is used to drive the generator and the battery mounted together with the internal combustion engine is charged, the compensation information is collected in the case where the internal combustion engine is stopped. In comparison with the case, the power consumption of the battery can be suppressed. In other words, the specific operational state capable of estimating the oxygen concentration in the intake air is a state in which the oxygen concentration previously stored in the calculation unit and the oxygen concentration in the intake air are the same. Further, the state in which the internal combustion engine is in operation refers to, for example, a state in which the internal combustion engine is driven (including an idling operation state) in a case where the key is not in an OFF (OFF) state. Further, the state in the case where the internal combustion engine is driven for a certain period of time is included in a state in which the internal combustion engine is in operation, regardless of whether or not the vehicle is traveling in the case where the internal combustion engine is installed in the vehicle.
In a preferred embodiment (2) of the sensor control device (1) of the present invention, the specific operational state is an opening degree of a control valve provided in the exhaust gas recirculation device for controlling the amount of exhaust gas for recirculation. a state less than a predetermined opening degree, wherein the exhaust gas recirculation device is configured to recirculate a portion of an exhaust gas of the internal combustion engine into the intake air, and an opening degree of the control valve is smaller than the predetermined opening degree The oxygen concentration in the intake air is previously stored in the calculation unit, and in a case where the opening degree of the control valve is smaller than the predetermined opening degree, the calculation unit collects the compensation information.
In a second aspect, the above object of the present invention is also achieved by providing an oxygen sensor comprising: a sensing element for measuring an oxygen concentration in an intake of an internal combustion engine, and a heater for sensing the feeling The measuring component performs heating; a state measuring unit for outputting a state signal corresponding to an operating state of the internal combustion engine; and a determining unit configured to determine whether the internal combustion engine is in a specific operating state based on the state signal; The sensor control device according to (1), wherein the calculation unit of the sensor control device collects the compensation information based on a determination result of the determination unit.
According to the invention, the sensor control device and the sensor control system can suppress the deterioration of the measurement accuracy of the oxygen sensor equipped with the heater while suppressing the power consumption of the battery mounted together with the internal combustion engine. This is because the compensation coefficient is calculated based on the compensation information collected in the case where the internal combustion engine is in operation and is in an operating state capable of estimating the oxygen concentration in the intake air.
