Motorcycle Exhaust Sensor Layout for Protection and Early Activation
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Solution Overview
Problem
The existing exhaust devices for straddle-type vehicles do not adequately protect gas sensors from flying objects and do not enhance their detection performance effectively.
Innovation Solution
The exhaust device design positions the gas sensor on the engine side within the exhaust passage, where it is protected by the exhaust passage from the front and lower sides and warmed by engine heat dissipation, improving its activation and detection performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the gas sensor is disposed at an appropriate distance from the engine or down tube, then the gas sensor can detect oxygen concentration in exhaust gas, but the gas sensor is exposed to flying objects from the front or lower side
Solution Approach 1:
The gas sensor is nested within the exhaust passage structure, specifically disposed on the upstream side of the catalyst within the exhaust passage. The exhaust passage itself serves as the protective structure, with the gas sensor integrated into its wall or internal surface, allowing the exhaust passage to protect the sensor from flying objects while maintaining detection capability.
Solution Approach 2:
The exhaust passage acts as an intermediary structure between the external environment (flying objects) and the gas sensor. By positioning the sensor within the exhaust passage rather than externally, the exhaust passage mediates the protection while the sensor remains in contact with exhaust gas for detection.
2Loss of time
If the gas sensor is brought close to the engine, then the gas sensor can be warmed by heat dissipation from the engine for early activation, but the gas sensor becomes more exposed to flying objects
Solution Approach 1:
The gas sensor is nested within the exhaust passage structure that is positioned close to the engine. This nesting allows the sensor to benefit from the thermal environment near the engine for faster activation while the exhaust passage structure provides protection from flying objects.
Solution Approach 2:
The exhaust passage, which could be seen as a constraint on sensor positioning, is converted into a beneficial protective structure. By placing the sensor within the exhaust passage rather than externally, the passage becomes a shield that protects the sensor from flying objects while allowing close proximity to the engine for thermal benefits.
3Reliability
If the gas sensor is disposed on the engine side within the exhaust passage, then the gas sensor is protected from flying objects and warmed by engine heat, but the exhaust passage structure becomes more complex
Solution Approach 1:
The exhaust passage is designed to serve multiple functions: it continues to guide exhaust gas from the engine through the catalyst to the exhaust outlet, and simultaneously provides protective enclosure for the gas sensor. This multi-functionality reduces the need for separate protective structures, thereby limiting the increase in overall device complexity.
Solution Approach 2:
The protective function for the gas sensor is merged with the exhaust passage structure itself. Rather than adding a separate protective housing or shield, the exhaust passage is designed to inherently protect the sensor by incorporating it into the passage walls or internal surfaces, combining structural and protective roles.
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 gas sensor is effectively protected from flying objects and achieves early activation and improved detection performance due to its proximity to the engine and integration within the exhaust passage.
Implementation Method 1
the gas sensor is disposed on the engine side with respect to the exhaust passage, the gas sensor is protected from a flying object from the front or the lower side by the exhaust passage
Implementation Method 2
the gas sensor is brought close to the engine, the gas sensor is warmed by heat dissipation from the engine
Data Source
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AI summary
An exhaust device in which an exhaust passage wraps around from a front side of an engine to a lower side of the engine and extends to a rear side is provided. The exhaust device includes a catalyst configured to purify exhaust gas in the exhaust passage and disposed in front of the engine, and a gas sensor disposed on a wall surface of the exhaust passage at an upstream side than the catalyst. The gas sensor is disposed in front of the engine so as to be directed toward the engine.