Piston Blow-By Valve Impact Detection
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Solution Overview
Problem
Internal combustion engines face catastrophic failure when a valve drops into contact with the piston, leading to costly damage requiring replacement of multiple components, including the power cylinder system, valve train, cylinder head, crankshaft, and engine block.
Innovation Solution
A piston design with a pocketed upper surface and a tubular member extending upwardly, where predetermined locations in the wall allow for a blow-by passage to be formed upon valve head impact, providing an immediate indication of the issue through increased gas/fuel mixture blow-by, which can be detected by a pressure sensor to prevent further engine damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a valve head impacts the piston during operation, then catastrophic damage occurs to the engine, but no immediate indication is provided to alert operators of the problem
Solution Approach 1:
The invention implements feedback by creating a detectable signal (blow-by gas flow) that provides immediate information about valve head misalignment. When the valve head impacts the piston, it opens a passage allowing combustion gases to escape into the cooling chamber, creating a measurable pressure change that alerts operators to the problem before catastrophic damage occurs.
Solution Approach 2:
The piston wall acts as an intermediary element between the combustion chamber and cooling chamber. By incorporating a frangible section that can be opened by valve head impact, the piston wall mediates the transmission of the malfunction signal from the combustion chamber to the cooling chamber, enabling detection without direct observation of the valve-piston contact.
2Strength
If the piston wall is made thick to prevent deformation, then structural strength is improved, but immediate detection of valve head impact becomes difficult
Solution Approach 1:
The piston wall is segmented into a frangible section and non-frangible sections. The frangible section is specifically designed with reduced thickness to be opened by valve head impact, while the non-frangible sections maintain the overall structural strength of the piston. This segmentation allows the piston to simultaneously achieve both strength and detectability.
Solution Approach 2:
The piston wall exhibits local quality variation where the frangible section has different thickness properties compared to the rest of the wall. This localized thinning creates a weak point that opens under impact conditions while the thicker surrounding areas maintain structural integrity, allowing the piston to be both strong and sensitive to malfunction.
3Difficulty of detecting and measuring
If a frangible section is created in the piston wall for detection, then immediate indication of problems is improved, but piston structural integrity is reduced
Solution Approach 1:
The frangible section is pre-positioned and pre-configured in the piston wall during manufacturing, creating a predetermined failure path before any malfunction occurs. This preliminary action ensures that when valve head misalignment happens, the opening occurs at the exact location and in the exact manner needed for detection, without compromising overall piston integrity.
Solution Approach 2:
The frangible section changes its physical state from closed to open under specific impact conditions. This parameter change (from intact to opened passage) provides the detection signal while the surrounding non-frangible sections maintain their original structural parameters, preserving overall piston integrity while enabling detection.
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 piston design prevents catastrophic engine failure by allowing for immediate detection of valve head misalignment, enabling shutdown and avoiding costly repairs by signaling a pressure change indicative of the problem.
Implementation Method 1
providing a sudden increase in blow-by, thereby providing an immediate indication of a problem
Data Source
AI summary
A piston and method is provided that inhibits the potential catastrophic damage to an internal combustion engine, thereby reducing the risk of costly damage to the engine. The piston includes a piston body having an upper combustion surface separated from an internal cooling chamber by a wall. The a pocket extends into the upper combustion surface to a closed bottom surface of the wall. A tubular member is disposed in the pocket. The tubular member extends upwardly from the upper surface. Should a valve head drop from its normal operating position, the valve head impacts the tubular member and forms a blow-by through passage extending from the upper combustion surface into the cooling chamber.