US-12625107-B2 - CO2 mass estimation system, exhaust gas composition ratio estimation method, and CO2 mass estimation method

Abstract

A CO 2 mass estimation system includes: an acquisition element acquiring detected values in accordance with concentrations of oxygen, H 2 O, and CO 2 contained in an engine exhaust gas output from a gas sensor; a setting element setting an air-fuel ratio of a mixture; and a calculation element calculating the mass of CO 2 contained in the exhaust gas, wherein the calculation element calculates the concentrations of oxygen, H 2 O, and CO 2 contained in the exhaust gas based on the sensor detected values, acquires concentrations of oxygen and H 2 O in air and the air-fuel ratio, calculates a composition ratio of at least C atoms contained in fuel based on the concentrations in the exhaust gas, the concentrations in the air, and the air-fuel ratio, and estimates the mass of CO 2 contained in the exhaust gas based on the composition ratio and the amount of injection of the fuel into the engine.

Inventors

• Yuichiro Kondo

Assignees

• NGK INSULATORS, LTD.

Dates

Publication Date

20260512

Application Date

20230317

Priority Date

20220331

Claims (2)

1. 1 . A system for estimating a mass of emission of CO 2 contained in an exhaust gas from an engine of a vehicle, the system comprising: an electronic control unit including an integrated control part, a fuel injection control part, an intake control part, a sensor detected value acquisition part, and a CO 2 mass calculation part; a gas sensor capable of outputting detected values in accordance with concentrations of oxygen, H 2 O, and CO 2 contained in a measurement gas; the sensor detected value acquisition part acquiring the detected values in accordance with the concentrations of oxygen, H 2 O, and CO 2 contained in the exhaust gas from the engine, the detected values being output from the gas sensor; and the fuel injection control part and the intake control part respectively controlling injection of fuel and air intake in accordance with an air-fuel ratio set by an air-fuel ratio setting element that sets the air-fuel ratio of a mixture of the fuel and the air supplied to the engine; wherein the CO 2 mass calculation part calculates the mass of emission of CO 2 contained in the exhaust gas, and wherein the CO 2 mass calculation part calculates the concentrations of oxygen, H 2 O, and CO 2 contained in the exhaust gas based on the detected values output from the gas sensor when the measurement gas is the exhaust gas, acquires concentrations of oxygen and H 2 O in air, acquires the air-fuel ratio set by the air-fuel ratio setting element, calculates a composition ratio of at least C atoms contained in the fuel based on the concentrations of oxygen, H 2 O, and CO 2 contained in the exhaust gas, the concentrations of oxygen and H 2 O in the air, and the air-fuel ratio acquired from the air-fuel ratio setting element, and estimates the mass of emission of CO 2 contained in the exhaust gas based on the calculated composition ratio and an amount of the injection of the fuel into the engine.
2. 2 . A method of estimating a mass of CO 2 contained in an exhaust gas from an engine of a vehicle, the method comprising: a) acquiring detected values in accordance with concentrations of oxygen, H 2 O, and CO 2 contained in the exhaust gas from the engine from a gas sensor capable of outputting the detected values in accordance with the concentrations of oxygen, H 2 O, and CO 2 contained in a measurement gas; b) calculating the concentrations of oxygen, H 2 O, and CO 2 contained in the exhaust gas based on the detected values; c) acquiring concentrations of oxygen and H 2 O in air; d) acquiring an air-fuel ratio of a mixture of fuel and air supplied to the engine; e) estimating a composition ratio of C atoms, H atoms, and O atoms contained in the fuel based on the concentrations of oxygen, H 2 O, and CO 2 CO 2 contained in the exhaust gas calculated in the step b), the concentrations of oxygen and H 2 O in the air acquired in the step c), and the air-fuel ratio acquired in the step d); and f) estimating the mass of CO 2 contained in the exhaust gas based on the composition ratio of C atoms contained in the fuel estimated in the step e) and an amount of injection of the fuel into the engine.

Description

CROSS-REFERENCE TO RELATED APPLICATION The present application claims priority from Japanese application JP2022-058417, filed on Mar. 31, 2022, the contents of which is hereby incorporated by reference into this application. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to estimation of the mass of CO2 contained in an exhaust gas from an engine of a vehicle. Description of the Background Art In measurement for managing the amount of an emitted exhaust gas from a vehicle, technology of measuring a concentration of carbon dioxide (CO2) has already been known (see Japanese Patent No. 5918177 and Japanese Patent No. 6469464, for example). In each of gas sensors disclosed in Japanese Patent No. 5918177 and Japanese Patent No. 6469464, in addition to a carbon dioxide (CO2) component, a water vapor (H2O) component can be measured in parallel. In management of the amount of the emitted exhaust gas of the vehicle, measurement of the mass of emission is more important than measurement of a concentration of emission in some cases (an example of a reference amount of emission: 95 g CO2/km or less). Japanese Patent No. 5918177 and Japanese Patent No. 6469464 disclose a method of measuring the concentration of CO2, but fail to disclose a method of measuring the mass of CO2. The mass can be calculated based on the concentration, but it requires measurement of mass flow of the exhaust gas. This is because there is a relationship expressed by an equation concentration of CO2×mass flow=mass of CO2. However, measurement of mass flow of the exhaust gas during travel of the vehicle is not necessarily easy, and addition of a component for measurement is not practical in terms of cost and the like. It is rather preferable to estimate the mass of emission of CO2 using existing components and information. SUMMARY The present invention is directed to estimation of the mass of CO2 contained in an exhaust gas from an engine of a vehicle. According to the present invention, a system for estimating the mass of CO2 contained in an exhaust gas from an engine of a vehicle includes: a gas sensor capable of outputting detected values in accordance with concentrations of oxygen, H2O, and CO2 contained in a measurement gas; a detected value acquisition element acquiring detected values in accordance with concentrations of oxygen, H2O, and CO2 contained in the exhaust gas from the engine, the detected values being output from the gas sensor; an air-fuel ratio setting element setting an air-fuel ratio of a mixture of fuel and air supplied to the engine; and a calculation element calculating the mass of CO2 contained in the exhaust gas, wherein the calculation element calculates the concentrations of oxygen, H2O, and CO2 contained in the exhaust gas based on the detected values output from the gas sensor when the measurement gas is the exhaust gas, acquires concentrations of oxygen and H2O in air, acquires the air-fuel ratio set by the air-fuel ratio setting element, calculates a composition ratio of at least C atoms contained in the fuel based on the concentrations of oxygen, H2O, and CO2 contained in the exhaust gas, the concentrations of oxygen and H2O in the air, and the air-fuel ratio acquired from the air-fuel ratio setting element, and estimates the mass of CO2 contained in the exhaust gas based on the calculated composition ratio and the amount of injection of the fuel into the engine. According to the present invention, the mass of CO2 contained in the exhaust gas when a certain mass of fuel is injected can be estimated without measuring mass flow of the exhaust gas. It is thus an object of the present invention to provide a method of estimating the mass of emission of CO2 contained in an exhaust gas without measuring mass flow. These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically shows one example of a configuration of a gas sensor 200; FIG. 2 schematically shows a configuration of a CO2 mass estimation system 1000; and FIG. 3 schematically shows a relationship among various parameters used for estimation of the mass of CO2. DESCRIPTION OF THE PREFERRED EMBODIMENTS <Configuration of Gas Sensor> FIG. 1 schematically shows one example of a configuration of a gas sensor 200 of a CO2 mass estimation system 1000 (FIG. 2) according to the present embodiment. The gas sensor 200 is a multi-gas sensor sensing a plurality of types of gas components and measuring concentrations thereof using a sensor element 201. Assume that at least water vapor (H2O) and carbon dioxide (CO2) are main sensing target gas components of the gas sensor 200 in the present embodiment. The gas sensor 200 further includes a controller 210 controlling operation of each part. As will be described below, the ga