Air-Fuel Ratio Sensor Mounting on Motorcycle Exhaust
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Solution Overview
Problem
Existing oxygen sensors in motorcycle exhaust systems are not suitable for linear detection of oxygen concentration over a wide range, affecting the accuracy of air-fuel ratio detection, particularly in multi-cylinder engines where precise control is necessary for optimal catalytic converter efficiency.
Innovation Solution
An air-fuel ratio sensor is mounted on the convergent connector of exhaust pipes, upstream of catalytic converters, to efficiently and accurately detect oxygen concentration across a wide range, improving combustion efficiency and catalytic converter effectiveness by using a minimum number of sensors strategically positioned to reduce installation space and enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an oxygen sensor is used to detect oxygen concentration in exhaust gas, then the sensor can determine whether the air-fuel ratio is rich or lean near stoichiometric ratio, but it cannot perform linear detection of oxygen concentration over a wide range
Solution Approach 1:
The patent changes the detection parameter from narrow-range oxygen sensing (lambda sensor) to wide-range oxygen concentration detection (air-fuel ratio sensor). This parameter change enables linear detection across a broad spectrum of oxygen concentrations, allowing the system to accurately measure both rich and lean conditions while maintaining measurement precision throughout the extended range.
2Measurement precision
If an air-fuel ratio sensor is mounted on exhaust pipes to detect oxygen concentration over a wide range, then detection accuracy is improved, but the sensor projection may obstruct exhaust gas flow
Solution Approach 1:
The patent positions the air-fuel ratio sensor on the outer circumferential surface of the exhaust pipe, utilizing the radial dimension rather than protruding into the exhaust flow path. This dimensional placement allows the sensor to detect oxygen concentration accurately while minimizing interference with exhaust gas flow, as the sensor element is oriented parallel to the flow direction rather than perpendicular to it.
3Measurement precision
If multiple sensors are installed on each exhaust pipe to improve detection accuracy, then measurement precision increases, but device complexity and installation space increase
Solution Approach 1:
The patent merges the detection function for multiple cylinders into a single air-fuel ratio sensor positioned on the exhaust pipe. By strategically placing one sensor per exhaust pipe that can detect the combined exhaust gas characteristics, the system achieves sufficient measurement precision without requiring multiple sensors per pipe, thereby reducing device complexity and installation space requirements.
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
The air-fuel ratio sensor effectively controls the oxygen concentration in exhaust gases, enhancing combustion efficiency and promoting the effectiveness of catalytic converters by accurately detecting oxygen levels across a wide range, even in multi-cylinder engines, with reduced sensor projection to ensure unobstructed gas flow.
Implementation Method 1
an air-fuel ratio sensor, mounted on at least one of a plurality of exhaust pipes connected to cylinders of the engine, for detecting the concentration of oxygen in exhaust gas of the motorcycle
Data Source
AI summary
A mounting structure is provided for an air-fuel ratio sensor on an exhaust pipe in a motorcycle in which a concentration of oxygen in an exhaust gas can be detected efficiently and accurately by the air-fuel ratio sensor. The air-fuel ratio sensor is mounted on a convergent connector of exhaust pipes, which, in turn, are operatively connected to the cylinders of a multi-cylinder engine. The air-fuel ratio sensor is located upstream of catalytic converters provided in the exhaust pipes, and may be mounted so as to be oriented substantially vertically when the motorcycle is in an upright configuration, or alternatively, may be inclined toward the rear of the motorcycle.