Coolant Viscosity Control for Engine Cooling Loss
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Solution Overview
Problem
Existing coolant compositions for internal combustion engines face challenges in maintaining optimal viscosity at both low and high temperatures, leading to inefficient cooling and fuel efficiency issues due to increased viscosity of glycols like ethylene glycol, which results in either cooling loss at low temperatures or insufficient cooling performance at high temperatures.
Innovation Solution
A coolant composition is developed by adjusting the kinetic viscosity using a combination of an alkali metal compound and a viscosity improving agent represented by the formula R1-O-(R2-O)m-SO3M, where R1 is a linear or branched alkyl group, R2 is an ethylene or propylene group, and m is between 0.5 to 10, along with a base of water and/or alcohol, to achieve a viscosity range of 8.5 mm2/sec at 25°C and 2.0 mm2/sec at 100°C, thereby reducing cooling loss and maintaining cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the concentration of glycol is increased to increase viscosity at low temperature, then cooling loss is reduced, but cooling performance at high temperature becomes insufficient
Solution Approach 1:
The patent applies parameter changes by using a viscosity index improving agent to modify the viscosity-temperature relationship of the coolant. This allows the coolant to maintain higher viscosity at low temperatures (reducing cooling loss) while keeping viscosity manageable at high temperatures (maintaining cooling performance), thus resolving the contradiction between these two requirements.
2Productivity
If the viscosity of coolant is reduced to improve fluidity at low temperature, then fuel efficiency is improved, but cooling loss increases
Solution Approach 1:
The viscosity index improving agent changes the viscosity parameters of the coolant across different temperatures. This enables the coolant to have lower viscosity at high temperatures (good fluidity and cooling) while maintaining higher viscosity at low temperatures (reducing cooling loss), thus resolving the contradiction between fluidity and cooling loss.
3Productivity
If a viscosity index improving agent is added to maintain fluidity at low temperature, then viscosity at high temperature is maintained, but cooling loss at low temperature cannot be reduced
Solution Approach 1:
The patent uses parameter changes through the viscosity index improving agent to achieve the opposite effect of conventional applications: instead of merely maintaining fluidity, it actively increases viscosity at low temperatures to reduce cooling loss while maintaining adequate fluidity at high temperatures for cooling performance.
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 coolant composition effectively reduces cooling loss at low temperatures and maintains cooling performance at high temperatures, enhancing the fuel efficiency of internal combustion engines by optimizing viscosity across temperature ranges.
Implementation Method 1
when the kinetic viscosity of a coolant composition is adjusted to be within a specific range by adding at least one alkali metal compound selected from the group consisting of alkali metal salts and alkali metal hydroxides in combination with a compound represented by the following formula (1) as a viscosity improving agent, cooling loss at a low temperature can be reduced
Implementation Method 2
when the viscosity is reduced, the thickness of a boundary layer between a coolant and a bore wall decreases, and convection is likely to be generated. Therefore, the coolant is likely to absorb heat from the bore wall
Implementation Method 3
the coolant is likely to absorb heat from the bore wall. As a result, cooling loss increases
Data Source
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AI summary
A coolant composition includes: a viscosity improving agent; at least one alkali metal compound selected from the group consisting of alkali metal salts and alkali metal hydroxides; and a base composed of water and/or at least one alcohol selected from the group consisting of a monohydric alcohol, a dihydric alcohol, a trihydric alcohol, and a glycol monoalkyl ether, wherein the viscosity improving agent is a compound represented by a formula of R1O-(R2O)m-SO3M, where R1 represents a linear or branched alkyl or alkenyl group having 16 to 24 carbon atoms, R2 represents an ethylene group or a propylene group, m represents an average addition molar number of R2O and a number from 0.5 to 10, and M represents a cation or a hydrogen atom, and a kinetic viscosity of the coolant composition is 8.5 mm2/sec or higher at 25°C and is 2.0 mm2/sec or lower at 100°C.