Marine Engine Cooling System with Split Flow and Bypass Circuit

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Solution Overview

Problem

Existing marine engine cooling systems face challenges in sequentially removing heat from selected engine components to prevent overcooling while ensuring sufficient heat removal, and in avoiding air pocket entrapment that can lead to overheating, particularly when using cold water as a coolant.

Innovation Solution

A method involving multiple streams of water pumped from a body of water, directed through specific paths within the engine, including an exhaust manifold, cylinder head, and engine block, with temperature-responsive valves controlling flow rates and directions to tailor heat removal based on component needs, and a dividing wall in the cylinder head to prevent air pocket accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If cold water from a body of water is used as the primary coolant, then heat removal from the engine is improved, but overcooling of certain engine portions occurs causing fuel vapor condensation and oil dilution

Engineering Contradiction:

Improveheat removal efficiencyVSAvoidovercooling damage

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The cooling system is divided into multiple independent circuits: a first cooling circuit for the exhaust manifold and a second cooling circuit for the cylinder head and block. This segmentation allows different coolant temperatures and flow rates to be applied to different engine components, preventing overcooling of the block while effectively cooling the exhaust manifold.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the engine receive customized cooling treatments. The exhaust manifold receives cooling water at a first temperature and flow rate optimized for heat removal, while the cylinder head and block receive cooling water at a second, higher temperature and different flow rate to prevent overcooling and fuel vapor condensation.

Inventive Principle:

Principle #3Local quality

2Loss of energy

If coolant flow rate is increased to remove heat from the exhaust manifold, then heat removal is improved, but air pockets may be trapped in the cooling system causing overheating

Engineering Contradiction:

Improveheat removal rateVSAvoidoverheating risk

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The system performs preliminary cooling of the exhaust manifold before cooling the cylinder head and block. By establishing proper coolant flow patterns and temperatures in the exhaust manifold first, the system prevents air pocket formation in critical areas before the main cooling cycle begins.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Temperature sensors monitor the cooling system and provide feedback to the controller. The controller adjusts coolant pump operation and valve positioning based on real-time temperature readings, maintaining optimal cooling rates while preventing air pocket entrapment and overheating conditions.

Inventive Principle:

Principle #23Feedback

3Device complexity

If a single cooling circuit is used for all engine components, then device complexity is reduced, but sequential heat removal control is lost

Engineering Contradiction:

Improvecooling system structureVSAvoidheat removal control

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cooling system employs dynamic control through electronically controlled valves and a variable speed coolant pump. The controller adjusts valve opening degrees and pump speed in real-time based on temperature sensor feedback, enabling sequential heat removal control from the exhaust manifold followed by the cylinder head and block.

Inventive Principle:

Principle #15Dynamics

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 approach effectively manages heat distribution across marine engine components, preventing overcooling and overheating by optimizing coolant flow sequences and velocities, ensuring efficient heat removal without damaging the engine through air pocket entrapment.

Implementation Method 1

directing the first stream of water through a cooling jacket of an exhaust manifold... directing second and third streams of water through a head of the engine... directing a fourth stream of the water through a block of the engine

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

pumping a first stream of water from a body of water... directing the first stream of water through a cooling jacket of an exhaust manifold, directing second and third streams of water through a head of the engine, directing a fourth stream of the water through a block of the engine

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS8763566B1Apparatus for cooling an engine of a marine propulsion system

Publication Date: 2014.07.01 BRUNSWICK CORP

AI summary

A cooling system for a marine engine is provided with various cooling channels which allow the advantageous removal of heat at different rates from different portions of the engine. A split flow of water is conducted through the cylinder head, in opposite directions, to individually cool the exhaust port and intake ports at different rates. This increases the velocity of coolant flow in the downward direction through the cylinder head to avoid the accumulation of air bubbles and the formation of air pockets that could otherwise cause hot spots within the cylinder head. A parallel coolant path is provided so that a certain quantity of water can bypass the engine block and avoid overcooling the cylinder walls.