CO Sensor Fuel Injection Control for Accurate Air-Fuel Ratio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional oxygen concentration sensors used in internal combustion engines are either too expensive for motorcycles and generators or fail to accurately detect oxygen concentrations when below a predetermined value, limiting effective air-fuel ratio control.
Innovation Solution
A fuel injection control apparatus utilizing a carbon monoxide concentration sensor in the exhaust path to detect CO levels, which are then used to control the fuel injection system to achieve a target air-fuel ratio, complemented by an oxygen concentration sensor for state discrimination and fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a linear AF sensor is used to accurately detect air fuel ratio, then measurement precision is improved, but device cost increases significantly
Solution Approach 1:
The patent replaces the expensive linear AF sensor with a much cheaper CO concentration sensor. Although CO sensors are generally less expensive, the system compensates for potential limitations by using multiple sensors (CO sensor and O2 sensor) to achieve accurate A/F ratio control, ensuring the solution remains cost-effective while maintaining measurement precision.
Solution Approach 2:
The patent introduces a conversion unit that converts CO concentration values into A/F ratio values using a predetermined conversion formula. This intermediary conversion process allows the system to use inexpensive CO sensors while still achieving accurate air fuel ratio measurement, effectively bridging the gap between low-cost sensing and precise measurement requirements.
2Ease of manufacture
If a general O2 sensor is used to detect oxygen concentration, then device cost is reduced, but measurement precision deteriorates when oxygen concentration is below predetermined value
Solution Approach 1:
The patent uses CO concentration as an intermediary parameter to represent A/F ratio. Instead of directly measuring oxygen concentration with a limited O2 sensor, the system measures CO concentration (which has a predictable relationship with A/F ratio) and converts it to A/F ratio values, thereby achieving accurate measurement across the full range of operating conditions.
Solution Approach 2:
The patent changes the measurement parameter from oxygen concentration to CO concentration. By measuring CO concentration instead of O2 concentration and using a conversion formula, the system achieves accurate A/F ratio control across all operating conditions, including lean conditions where traditional O2 sensors fail.
3Adaptability or versatility
If CO concentration sensor is used instead of O2 sensor, then device cost is reduced and adaptability is improved, but measurement precision may deteriorate
Solution Approach 1:
The patent implements a feedback control system where the control unit adjusts fuel injection based on the converted A/F ratio information from CO sensor measurements. This closed-loop feedback ensures that despite using a different sensor type, the system maintains accurate A/F ratio control by continuously adjusting fuel supply to achieve the target A/F ratio.
Solution Approach 2:
The conversion unit serves as an intermediary that translates CO concentration measurements into meaningful A/F ratio values. This conversion process, based on predetermined formulas, ensures that the measurements from the CO sensor are accurately translated into precise A/F ratio information, maintaining measurement precision while enabling the use of cheaper, more adaptable sensors.
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
This solution provides accurate and cost-effective air-fuel ratio control in internal combustion engines, enabling precise fuel injection management and low-cost implementation, while also detecting sensor faults for maintenance.
Implementation Method 1
a carbon monoxide concentration sensor provided in an exhaust path of the internal combustion engine and configured to detect a carbon monoxide concentration in an exhaust gas
Data Source
AI summary
A fuel injection control apparatus is provided. An injection unit injects fuel in an internal combustion engine. A carbon monoxide concentration sensor is provided in an exhaust path of the internal combustion engine and detects a carbon monoxide concentration in an exhaust gas. A control unit controls the injection unit based on the carbon monoxide concentration detected by the carbon monoxide concentration sensor such that an air fuel ratio in the internal combustion engine becomes close to a target air fuel ratio.