Insulated Engine Piston and Liner Segmentation Against Thermal Shock
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Solution Overview
Problem
Heat-resistant materials used in engine components, such as pistons and cylinder liners, exhibit poor machinability and are prone to thermal shock, leading to increased heat loss, gas leakage, and potential damage due to their brittle nature and low compressive and tensile strength.
Innovation Solution
The design incorporates smaller pieces of heat-resistant materials connected with prestressing forces and embedded with fibers, which are polymerized or woven into cloth forms to enhance strength and thermal shock resistance, and the use of external heating to redirect exhaust gases during fuel injection cessation to maintain temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat-resistant material is used for piston and cylinder components, then thermal insulation performance is improved, but machinability deteriorates and manufacturing precision becomes difficult to achieve
Solution Approach 1:
The piston is divided into multiple segments including a piston head made of heat-resistant material and a piston body made of conventional material. The cylinder liner is segmented into an upper portion with heat-resistant material and a lower portion with conventional material. This segmentation allows each part to have optimized properties for its specific function while maintaining manufacturability.
Solution Approach 2:
The invention uses composite construction by combining heat-resistant materials (such as ceramics or heat-resistant alloys) with conventional engine materials (such as aluminum alloy or steel). The heat-resistant material layers are applied as coatings or linings on the piston and cylinder components, creating a composite structure that provides thermal insulation where needed while maintaining the structural integrity and manufacturability of the base materials.
2Temperature
If heat-resistant material is used for piston and cylinder components, then thermal insulation performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
By segmenting the piston and cylinder liner into zones with different material requirements, the invention reduces the overall manufacturing precision burden. The heat-resistant material layers can be applied as separate components or coatings that do not require the entire component to be machined to high precision, only the interfacing surfaces.
Solution Approach 2:
The composite structure allows the base conventional material components to be manufactured with standard precision techniques, while the heat-resistant material layers are added subsequently through coating or lining processes that are optimized for their specific material properties rather than requiring high-precision machining of the entire component.
3Loss of energy
If gap between piston insulation layer and cylinder insulation layer is increased, then heat loss is reduced, but gas leakage increases
Solution Approach 1:
The piston cross-section is designed with non-uniform geometry where the upper portion has a smaller cross-sectional area and the lower portion has a larger cross-sectional area. This creates a tapered configuration that allows the gap between piston and cylinder insulation layers to vary along the height, providing different functional characteristics at different locations.
Solution Approach 2:
The variable gap configuration dynamically adapts to the piston's position in the cylinder during operation. When the piston is at top dead center, the smaller upper gap minimizes heat loss during the combustion phase, while the larger lower gap accommodates thermal expansion and prevents excessive pressure buildup during the power stroke.
4Use of energy by moving object
If engine operates without fuel injection (e.g., during slipping), then fuel consumption is reduced, but thermal shock to insulation layer increases causing damage
Solution Approach 1:
The engine control system anticipates periods without fuel injection (such as during slipping or idle conditions) and takes preliminary action by redirecting hot exhaust gases back into the cylinder before the thermal shock occurs. This pre-heating action maintains the temperature of the insulation layers and prevents sudden thermal contraction that would cause damage.
Solution Approach 2:
The invention converts the potentially harmful effect of hot exhaust gases (which could increase emissions or temperature) into a beneficial pre-heating mechanism during no-fuel-injection periods. By redirecting exhaust gases back into the cylinder, the system uses the thermal energy that would otherwise be wasted to protect the insulation layers from thermal shock, turning a potential harm into a protective benefit.
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 reduces thermal stress, minimizes gas leakage, and maintains structural integrity by distributing thermal loads and using heat-resistant fibers to reinforce components, thereby ensuring consistent operation and reduced risk of damage from thermal shock.
Implementation Method 1
a heater, such as an electric heater and / or a chemical reaction heater can be used to heating up the exhaust gas flowing path so to heat up the exhaust gas
Implementation Method 2
the heat-resistant material that acts as the piston or part of the piston at the piston position as a 'piston insulation'. And the heat-resistant material of a portion or all of the cylinders and / or cylinder liner to be a 'cylinder insulation layer'
Data Source
AI summary
Improving an IC Engine’s thermal efficiency by heat preservation by providing: heat insulation layers to the cylinder, piston crown, combustion chamber and cylinder-head including internal gaps/cavities with or without vacuum; reduced carbonisation of fuel and oil; reduced the thermal shock by exhaust gas recirculation - EGR with control/intake valves, heating and storage tank; improved thermal shock resistance of insulation with flexible/porous thread/fibre and cloth materials bound together by binding with paste, stitching, weaving, braiding or pressed/clamped together; improved distortion resistance using sapphire or tungsten steel; an elongated piston cap or cone; segmented or annular sheet cylinder/liner construction; direct or indirect cooling of fuel injectors with fuel recirculation or spark plugs with high pressure gas jets in pits or slits.