Marine Engine Exhaust Conduit Preventing Water Ingress
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Solution Overview
Problem
Conventional marine engine assemblies face challenges in positioning the engine lower relative to the watercraft while maintaining proper propeller depth, which increases the risk of water entering the engine through the exhaust manifold.
Innovation Solution
The marine engine assembly features a modified exhaust conduit that extends forward and upward from the engine unit, then downward and rearward to an exhaust outlet, positioned below the engine unit, preventing water ingress even when fully trimmed, and functions as an expansion chamber for two-stroke engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the engine unit is positioned lower relative to the watercraft, then more useable room is available in the watercraft, but the risk of water entering the engine via the exhaust manifold increases
Solution Approach 1:
The exhaust conduit is designed to extend in a multi-dimensional path rather than a straight horizontal route. It extends forward and upward from the exhaust inlet, then curves downward and rearward to the exhaust outlet, creating a three-dimensional configuration that utilizes vertical space to prevent water ingress while maintaining engine positioning
2Length of moving object
If the engine unit is positioned lower, then the overall length of the engine assembly below the engine unit is shortened, but the propeller depth may be compromised
Solution Approach 1:
The exhaust conduit utilizes vertical dimension by extending upward from the exhaust inlet before curving downward to the outlet. This vertical component allows the engine to be positioned lower while maintaining the propeller at the correct water depth, as the conduit length in the vertical direction does not affect the horizontal propeller position
3Stability of the object's composition
If a long exhaust path through the midsection is used, then the engine can be positioned higher, but the overall engine assembly length increases
Solution Approach 1:
The patent removes the traditional midsection component entirely and connects the lower unit directly to the engine unit. This extraction of the midsection eliminates the need for a long exhaust path through it, allowing the exhaust conduit to be redesigned with a more compact, multi-dimensional configuration that achieves the same functional goals without increasing overall assembly length
Data Source
AI summary
A watercraft and a marine engine assembly for pivotably mounting to a watercraft about a tilt-trim axis are disclosed. The marine engine assembly includes an engine unit including: an engine unit housing; an engine disposed in the housing; and an exhaust conduit disposed in the housing, an exhaust inlet defined by the exhaust conduit being fluidly connected to the engine, the exhaust conduit extending forward and upward from the exhaust inlet and then subsequently extending downward and rearward to an exhaust outlet. The marine engine assembly also has a driveshaft operatively connected to the engine and a propulsion device operatively connected to the driveshaft. A center of mass of the engine is disposed below the tilt-trim axis at least when the driveshaft is vertically oriented.