SOx Sensor Voltage Reduction Control for Low Oxygen Precision
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Solution Overview
Problem
Existing methods for detecting sulfur oxide (SOx) concentration in internal combustion engine exhaust gas lack precision, particularly when oxygen concentration is low, affecting the accuracy of SOx-related parameter calculation.
Innovation Solution
A control apparatus and method for internal combustion engines using a limiting current sensor with an electronic control unit that implements voltage reduction control to calculate SOx parameters, where the oxygen concentration is actively controlled below a predetermined level during voltage reduction, allowing for precise SOx concentration measurement by isolating the output current corresponding to SOx.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage reduction control is implemented to measure SOx concentration, then measurement precision of SOx is improved, but the accuracy deteriorates when oxygen concentration is high because oxygen interferes with the measurement
Solution Approach 1:
The patent changes the oxygen concentration parameter by controlling engine operation to create low oxygen concentration conditions (such as during EGR operation or post-injection) before performing voltage reduction control for SOx measurement. This parameter change eliminates oxygen interference and enables accurate SOx measurement.
Solution Approach 2:
The patent performs preliminary action by controlling the engine to reduce oxygen concentration in the exhaust gas before the actual SOx measurement is taken. This preliminary oxygen reduction prepares the measurement environment to ensure accurate SOx detection without oxygen interference.
2Difficulty of detecting and measuring
If a limiting current sensor is used to detect SOx, then detection capability is improved, but device complexity increases due to the need for voltage control and oxygen concentration management
Solution Approach 1:
The patent utilizes the existing limiting current sensor's capability to detect both oxygen and SOx, making the sensor serve multiple functions. The sensor itself provides the basis for both oxygen concentration detection and SOx measurement, eliminating the need for separate detection systems and reducing overall device complexity.
Solution Approach 2:
The limiting current sensor is designed to perform multiple functions: detecting oxygen concentration for engine control and detecting SOx concentration for emission monitoring. This multi-functionality reduces the need for additional sensors and simplifies the overall detection system while maintaining high detection capability for SOx.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-precision calculation of SOx-related parameters by ensuring a large proportion of the output current during voltage reduction corresponds to SOx levels, even in low oxygen concentration conditions, thereby improving detection accuracy and reliability.
Implementation Method 1
a limiting current sensor... calculate a parameter relating to SOx contained in a detection subject gas using an output current of the sensor obtained when voltage reduction control is implemented to reduce an applied voltage applied to the sensor
Implementation Method 2
implement the voltage reduction control when an oxygen concentration of the detection subject gas is less than a predetermined concentration... a small proportion of the output current obtained during the voltage reduction control is occupied by an output current generated as a result of the oxygen concentration
Data Source
AI summary
A control apparatus for an internal combustion engine having a limiting current sensor includes an electronic control unit. The electronic control unit is configured to: (i) calculate a parameter relating to SOx contained in a detection subject gas using an output current of the sensor obtained when voltage reduction control is implemented to reduce an applied voltage applied to the sensor from a parameter calculation voltage; and (ii) implement the voltage reduction control when an oxygen concentration of the detection subject gas is less than a predetermined concentration or a low oxygen concentration condition, according to which an oxygen concentration of the detection subject gas is predicted to be less than a predetermined concentration, is established.