Compact Engine Oxygen Sensor Mounting via Cylinder Head Projection
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Solution Overview
Problem
Existing engine designs with oxygen concentration sensors project outwardly, increasing engine size and compromising compactness, especially in single-cylinder and V-twin-cylinder engines where traditional compactness is a key advantage.
Innovation Solution
A single-cylinder or V-twin-cylinder engine design featuring a cylinder head with a projected portion that houses the oxygen concentration sensor, where the sensor's main body and detection portion overlap the projected portion when viewed from the cylinder axis, ensuring the sensor is within the exhaust gas passage and does not project outwardly, allowing for a compact engine structure without increasing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the oxygen concentration sensor is mounted on the cylinder head at a position where exhaust gas has high temperature, then the sensor can be heated quickly to activation temperature without a heater, but the sensor projects outwardly from the cylinder head increasing engine size
Solution Approach 1:
The patent repositions the oxygen concentration sensor along the exhaust gas passage such that the detection portion is located downstream within the passage. This spatial rearrangement allows the sensor to be heated by exhaust gas flow while the main body is positioned upstream, preventing outward projection and maintaining compact engine dimensions without sacrificing heating efficiency.
2Measurement precision
If the oxygen concentration sensor is mounted within the exhaust gas passage to ensure accurate detection, then detection precision is improved, but the sensor structure becomes more complex
Solution Approach 1:
The exhaust gas passage is designed to serve dual functions: as the flow path for exhaust gas and as the mounting structure for the oxygen concentration sensor. The sensor is positioned within the passage itself, eliminating the need for separate mounting brackets or housings, thereby reducing structural complexity while ensuring accurate oxygen concentration detection.
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 design prevents the oxygen concentration sensor from projecting outward, maintaining the engine's compactness in the left-right direction and reducing overall size increase, while ensuring effective heating of the sensor by high-temperature exhaust gas, eliminating the need for separate heating mechanisms.
Implementation Method 1
the oxygen concentration sensor is heated by high-temperature exhaust gas in the exhaust gas passage, and is heated quickly to an activation temperature of the sensor
Data Source
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AI summary
There is provided an engine in which a projection of the oxygen concentration sensor outwardly of the cylinder head can be prevented and engine size increase is reduced even if the oxygen concentration sensor is provided at a position at which the exhaust gas has a high temperature in the cylinder head. Also, there is provided a saddle-riding type vehicle which includes the engine. An engine 36 includes: a cylinder head 46 which has a projected portion 66 projecting outwardly from a head main body 65; a combustion recess 70 formed in the head main body 65; an exhaust gas passage 80 from the combustion recess 70 through the projected portion 66 for discharging exhaust gas from the combustion recess 70; and an oxygen concentration sensor 50 which has a main body portion 118 and a detection portion 120. The oxygen concentration sensor 50 is mounted to the projected portion 66. The main body portion 118 and the detection portion 120 overlap the projected portion 66 when viewed from the direction of a cylinder axis A. Further, at least part of the detection portion 120 is located within the exhaust gas passage 80.