Straddle-Type Vehicle Engine Auxiliary Air Intake Passage Design
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Solution Overview
Problem
Existing engine units for straddle-type vehicles face challenges in promoting fuel disintegration for higher combustion efficiency while suppressing turbulent flow towards auxiliary passages, often requiring complex constructions and higher costs due to the need for control valves and controllers.
Innovation Solution
A vehicle engine unit with a cylinder head, air intake pipe, throttle body, and auxiliary air intake passage that meanders to increase its length, reducing turbulent flow by enhancing fluid resistance without increasing the distance between throttle valves and the combustion chamber, thus maintaining a simple and cost-effective design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a communication passage is provided between the main passage and auxiliary passage with a control valve, then turbulent flow of fuel toward the auxiliary passage is suppressed, but device complexity increases due to control valve and controller
Solution Approach 1:
The invention extracts and eliminates the control valve and controller from the system by redesigning the auxiliary air intake passage to inherently prevent fuel turbulent flow through its meandering configuration, achieving the same protective function without the complex control components
Solution Approach 2:
The auxiliary air intake passage is designed with a meandering (curved) configuration instead of a straight path. This curvature creates fluid resistance that suppresses turbulent flow of fuel toward the auxiliary passage, replacing the need for active control mechanisms
2Object-affected harmful factors
If the auxiliary air intake passage is lengthened to increase fluid resistance, then turbulent flow is suppressed, but the distance between throttle valves and combustion chamber increases, reducing throttle responsiveness
Solution Approach 1:
The auxiliary air intake passage is configured to meander in three-dimensional space rather than extending linearly. This allows the passage to achieve sufficient length for fluid resistance and turbulent flow suppression while maintaining a compact overall layout that preserves quick throttle response
3Object-affected harmful factors
If a control valve is used to manage pressure difference in the auxiliary passage, then fuel turbulent flow is prevented, but manufacturing cost increases
Solution Approach 1:
The invention replaces expensive control valves and controllers with a simple meandering passage geometry that achieves the same protective function through passive fluid dynamics, significantly reducing manufacturing costs while maintaining effectiveness
Solution Approach 2:
The meandering auxiliary air intake passage passively suppresses fuel turbulent flow through its own geometric configuration and the resulting fluid resistance, eliminating the need for external control systems and reducing overall system cost
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 engine unit achieves higher fuel combustion efficiency and improved responsiveness to throttle operations while preventing turbulent flow into the auxiliary passage, ensuring efficient fuel disintegration and reduced variations in fuel supply to the combustion chamber.
Implementation Method 1
The auxiliary air intake passage has a center axis having opposite ends, and crosses a plane containing a straight line segment that extends between the opposite ends of the center axis of the auxiliary air intake passage. The line segment is a straight line that connects the opposite ends of the center axis so that the line segment has a minimal length.
Data Source
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AI summary
An intake air pipe 62 connected to a cylinder head 22 defines a part of a main air intake passage B3. Two throttle valves 69A,69B are disposed in a tubular member 64 spaced apart from each other in an intake air flow direction El.An auxiliary air intake passage C1 communicating with a portion of the main air intake passage B3 between the two throttle valves 69A,69B to guide intake air into a space adjacent to the injector 47 at least during idling is formed. The center axis F1 of the auxiliary air intake passage C1 crosses a plane G2. The plane G2 contains a straight line segment G1 that extends between the opposite ends F2, F3 of the center axis F1.