Ceramic Engine Pistons With Phase-Change Cooling for Thermal Stress
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Solution Overview
Problem
Internal combustion engines waste around one third of their energy to cooling systems due to metal components, leading to low operating efficiencies, and technical ceramics are brittle and crack under high tensile cyclic loads and temperature gradients.
Innovation Solution
Utilizing technical ceramic materials, particularly silicon-based ceramics like Silicon Nitride, for pistons and cylinders in an opposed configuration, with heat transfer members that change state to manage thermal stress and reduce tensile loads, and incorporating insulation and cooling arrangements to mitigate thermal gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If technical ceramic materials are used to replace metal components, then thermal efficiency is improved and energy wastage is reduced, but the components become brittle and crack readily under tensile cyclic loads and high temperature gradients
Solution Approach 1:
The patent changes the operating parameters by maintaining combustion chamber temperatures above 1000°C and ensuring temperature gradients across ceramic components remain below 100°C. This parameter control allows ceramic materials to operate in their optimal thermal range while avoiding the temperature differential that causes thermal shock and cracking, thereby resolving the contradiction between thermal efficiency and component reliability
Solution Approach 2:
The patent employs composite construction by combining technical ceramic materials with metallic components in specific configurations. The ceramic materials provide thermal efficiency benefits while metallic components or coatings protect against tensile cyclic loads and thermal shock, creating a hybrid system that achieves both improved thermal efficiency and maintained reliability
2Productivity
If technical ceramic materials are used to replace metal components, then brake thermal efficiency increases to at least 70%, but the components are susceptible to cracking under high temperature gradients
Solution Approach 1:
The patent applies beforehand cushioning by pre-heating ceramic components to near operating temperatures before exposing them to extreme thermal conditions, and by designing thermal barriers and insulation systems that cushion against sudden temperature changes. This prevents thermal shock before it can cause cracking, allowing the system to achieve high brake thermal efficiency while protecting ceramic components from harmful temperature gradients
Solution Approach 2:
The patent严格控制 temperature gradients across ceramic components to remain below 100°C by adjusting heating rates, improving thermal conductivity pathways, and optimizing insulation configurations. This parameter control enables the system to maintain high productivity through efficient heat utilization while preventing the thermal shock that would otherwise damage ceramic components
3Reliability
If metal components are used in conventional internal combustion engines, then components can withstand tensile cyclic loads, but energy wastage to cooling systems reduces operating efficiency to around 30%
Solution Approach 1:
The patent fundamentally changes the material parameter from metal to technical ceramic, which has inherently lower thermal conductivity. This parameter change allows the ceramic components to retain heat better, reducing the energy wastage to cooling systems while maintaining reliability through controlled temperature gradients and protective design features that prevent thermal shock and mechanical failure
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
Achieves a life of at least 30,000 hours with a brake thermal efficiency of at least 70% by eliminating tensile cyclic loads and significant temperature gradients.
Implementation Method 1
the heat transfer member is reconfigurable from a first, solid, state to a second state in which at least part of the heat transfer member is in a liquid state
Data Source
AI summary
A piston arrangement (12) for an internal combustion engine (10) comprises one or more pistons (14) which are at least partly constructed from a technical ceramic material. An axially disposed bore (20) for receiving a heat transfer member (22) is provided in at least one of the pistons (14). The heat transfer member (22) is reconfigurable from a first, solid, state to a second state in which at least part of the heat transfer member (22) is in a liquid state so as to transfer heat away from and thus cool the piston rod (16) as the piston reciprocates. A cylinder arrangement (46) for the internal combustion engine (10) comprises one or more cylinders (48) which are at least partly constructed from a technical ceramic material. One or more grooves (54) are formed in the cylinder (48), to decrease the thermal gradient between the inside and outside of the cylinder (48). A piston (14) for the internal combustion engine (10) comprises a piston rod (16) and a piston crown (18) which is at least partly constructed from a technical ceramic material. An insulation arrangement (40) between the piston rod (16) and the piston crown (18) comprises segments (42) configured such that when disposed on the piston rod (16) axial slots or spaces are defined between the segments (42).