Amphibious Vehicle Exhaust Cooling System
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Solution Overview
Problem
Amphibious vehicles face unique challenges in cooling their exhaust systems, as they must function effectively both on land and water, where traditional land and marine cooling methods are inadequate due to insulation and thermal shock concerns, and require maintaining the catalytic converter at optimal temperature to prevent damage.
Innovation Solution
An exhaust cooling system comprising an air-liquid heat exchanger and a liquid-liquid heat exchanger, with a closed coolant liquid circuit that uses air-liquid heat exchange on land and liquid-liquid heat exchange at sea, allowing for efficient cooling without relying on external water sources, and incorporating a water jacket to manage thermal transfer and prevent condensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the exhaust system is sealed inside the hull to ensure buoyancy and hydrodynamic performance, then the vehicle's marine performance is improved, but the exhaust system becomes insulated from external cooling influences causing overheating
Solution Approach 1:
The exhaust system is divided into separate sealed sections within the hull, with dedicated cooling channels created inside the exhaust pipes. This segmentation allows the exhaust system to remain sealed for buoyancy while providing internal pathways for cooling fluid circulation to manage heat.
Solution Approach 2:
A cooling fluid circulation system is nested within the exhaust system structure. The cooling channels are integrated inside the exhaust pipes, creating a concentric arrangement where the cooling system is contained within the exhaust system, allowing heat transfer from the exhaust gases to the cooling fluid.
2Temperature
If the exhaust system is cooled using raw water from external sources, then cooling efficiency is improved, but the system cannot function on land where water sources are unavailable
Solution Approach 1:
The cooling system is designed to perform multiple functions: it can use raw water from external sources when available (marine mode) and switch to a closed-loop recirculating system using a coolant mixture when raw water is unavailable (land mode). This multi-functionality allows the same system to operate effectively in both environments.
Solution Approach 2:
The system dynamically adapts its cooling method based on operational conditions. Flow control valves and pumps can switch between open raw water circulation and closed-loop coolant recirculation, allowing the system to optimize cooling performance for either land or marine operation.
3Temperature
If the exhaust system is rapidly cooled when entering water from land mode, then thermal management is improved, but thermal shock effects may damage the exhaust system
Solution Approach 1:
The cooling system begins cooling the exhaust system gradually before the vehicle enters water, using the closed-loop coolant system to reduce temperatures in a controlled manner. This preliminary cooling action prevents sudden thermal shock when transitioning to marine mode.
Solution Approach 2:
The system uses a coolant mixture with appropriate thermal properties and controlled flow rates to cushion the thermal transition. The coolant acts as a buffer, absorbing heat gradually and preventing abrupt temperature changes that could cause thermal shock damage to the exhaust system.
4Reliability
If the catalytic converter is maintained at high temperature to prevent damage, then catalyst performance is improved, but the risk of igniting surrounding materials increases
Solution Approach 1:
The cooling system applies localized cooling to different parts of the exhaust system. The catalytic converter receives controlled cooling to maintain its optimal operating temperature range, while other sections of the exhaust system can be cooled more aggressively to reduce ignition risk to surrounding materials.
Solution Approach 2:
Temperature sensors monitor the catalytic converter and exhaust system temperatures, providing feedback to the cooling system control. This allows the system to adjust coolant flow rates to maintain the catalytic converter at its optimal temperature while preventing excessive temperatures that could ignite surrounding materials.
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 system effectively cools the exhaust system in both land and marine modes, preventing thermal shock and maintaining the catalytic converter's optimal temperature, thus ensuring the longevity and performance of the vehicle's exhaust components.
Implementation Method 1
when the amphibious vehicle is operated in land mode the coolant liquid is heated by the exhaust system and cooled by the at least one air-liquid heat exchanger
Implementation Method 2
the apparatus and methods employed for cooling exhaust systems are well established. In the case of a land vehicle, the exhaust system is typically slung below the floor panel of the vehicle such that it is exposed to ambient atmospheric air which passes over and cools external surfaces of the exhaust system
Implementation Method 3
when the amphibious vehicle is operated in marine mode the coolant liquid is heated by the exhaust system and cooled by the at least one liquid-liquid heat exchanger
Implementation Method 4
In the case of marine vessels, it is usual to cool exhaust systems with water. This is normally achieved using the abundant resource of raw water outside the vessel which is drawn in and circulated around a water jacket enclosing the exhaust system
Implementation Method 5
raw water which is drawn in and circulated around a water jacket enclosing the exhaust system
Data Source
AI summary
An exhaust cooling system of an amphibious vehicle operable in land and marine modes comprises an exhaust system to be cooled, at least one air-liquid heat exchanger, at least one liquid-liquid heat exchanger, and coolant liquid in thermal communication with the exhaust system to be cooled, the air-liquid heat exchanger(s) and/or the liquid-liquid heat exchanger(s) and heated by the exhaust system. When the amphibious vehicle is operated in land mode, the coolant liquid is cooled by the air-liquid heat exchanger(s). When the vehicle is operated in marine mode, the coolant liquid is cooled by the liquid-liquid heat exchanger(s). The air-liquid heat exchanger(s) may also be used on water. The vehicle may plane, and have retractable road wheels. The air-liquid heat exchanger(s) may be mounted at the front or rear of the vehicle, or elsewhere.