Exhaust Pipe Layout for Accurate Sensor Detection in Motorcycle Engines
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Solution Overview
Problem
Exhaust gas sensors in straddle-type vehicles are prone to damage and experience reduced detection accuracy due to the curved exhaust pipes, which deviate the flow of exhaust gas and increase the risk of collision with obstacles.
Innovation Solution
The exhaust pipe is designed to extend downward through one lateral side of the down frame, cross the front side, and then upward through the other lateral side, with the exhaust gas sensor attached to a straight portion that overlaps the down frame, positioned approximately perpendicular to the gas flow, and the lead wire routed along the frame to stabilize support and reduce vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the exhaust pipe has many bends to pass through the down frame, then the exhaust pipe can be routed through the vehicle frame, but the flow of exhaust gas is deviated, deteriorating detection accuracy of the exhaust gas sensor
Solution Approach 1:
The exhaust pipe is divided into multiple sections: a first section extending downward from the exhaust port, a second section extending upward through the down frame, and a third section extending rearward. This segmentation allows the pipe to navigate the vehicle frame structure while maintaining a straight detection section for accurate sensor operation.
Solution Approach 2:
The exhaust pipe utilizes three-dimensional space by extending in multiple directions (downward, upward through the frame, and rearward) to achieve proper routing while preserving a straight portion for detection purposes.
2Ease of operation
If the exhaust pipe has many bends, then the exhaust pipe can pass through the down frame, but there is a high risk of damage to the exhaust gas sensor or lead wire
Solution Approach 1:
The exhaust pipe is segmented into routing sections and a straight detection section. The sensor and lead wire are installed on the straight section that passes through the down frame, which experiences less vibration and stress, thereby improving reliability and reducing damage risk.
Solution Approach 2:
The sensor installation location is extracted from the bent portions of the exhaust pipe and placed specifically on the straight section that crosses the down frame. This separation protects the sensor from the mechanical stresses associated with pipe bends.
3Reliability
If the exhaust pipe extends downward and crosses the front side of the down frame, then the sensor can be positioned internally, but the exhaust pipe requires a complex path
Solution Approach 1:
The exhaust pipe is divided into distinct functional sections: a routing section that navigates the complex path through the down frame, and a straight detection section where the sensor is installed. This segmentation allows the pipe to achieve both protection and simplicity where needed.
Solution Approach 2:
The exhaust pipe utilizes vertical dimension by extending downward and upward through the down frame, creating a three-dimensional routing path that achieves sensor protection while maintaining a manageable configuration.
Data Source
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AI summary
An engine (40) for a straddle-type vehicle (1). The straddle-type vehicle (1) is to be mounted on a vehicle frame (10) in which a down frame (14) extends downward from a head pipe (11). The engine (40) includes a cylinder head (43) having an exhaust port (47) formed thereon, an exhaust pipe (70), and an exhaust gas sensor (84) attached to the exhaust pipe (70). The exhaust pipe (70) extends downward passing through a first lateral side of the down frame (14), crosses a front side of the down frame (14), and extends upward passing through a second lateral side of the down frame (14). A part of the exhaust pipe (70) that crosses the down frame (14) is a straight portion (73). The exhaust gas sensor (84) is attached to the straight portion (73) and overlaps the down frame (14) from the front side.