Piston Crevice Fluid Sampling via Cylinder Wall Passage
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Solution Overview
Problem
Existing methods for sampling fluid from piston top land crevices in internal combustion engines are ineffective in collecting and preserving a sufficient volume of fluid to fully understand the composition, which is crucial for addressing low speed pre-ignition issues and emissions control.
Innovation Solution
A sampling system that accesses the top land crevice through a small passage in the cylinder wall, using a combination of a relief valve and a piloted check valve to collect micro-samples near the top-dead-center of the compression stroke, with a solenoid valve for control and an inert flush gas for sample purity, allowing for minimal disruption to engine operation and efficient fluid analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If past sampling methods using tubing through the piston and connecting rod are used, then access to the crevice is achieved, but the device complexity and disruption to engine operation increase
Solution Approach 1:
The sampling system extracts the sampling function from the complex existing method by using a simple passage through the cylinder wall instead of tubing through the piston and connecting rod. The sampling device is removed from the crankcase and repositioned to access the crevice directly through the cylinder wall, simplifying the overall system while reducing engine operation disruption.
Solution Approach 2:
The passage through the cylinder wall serves as an intermediary structure that enables sampling without requiring complex internal routing through the piston and connecting rod. This intermediary access point allows the sampling device to reach the crevice region while maintaining engine operation and reducing system complexity.
2Quantity of substance
If existing sampling methods are used, then crevice fluid can be sampled, but insufficient fluid volume is collected for full compositional analysis
Solution Approach 1:
The system performs preliminary actions by collecting multiple micro-samples during the compression stroke before the piston reaches top dead center. These micro-samples are accumulated in a collection chamber, ensuring sufficient total fluid volume is gathered for comprehensive compositional analysis while maintaining reliable sampling effectiveness.
Solution Approach 2:
The sampling system maintains continuous useful action by repeatedly drawing micro-samples throughout the compression stroke and accumulating them in the collection chamber. This continuous accumulation ensures sufficient fluid volume is collected for full compositional analysis, improving both sample quantity and sampling reliability.
3Ease of operation
If sampling is performed during normal engine operation, then minimal disruption is achieved, but sample purity may be compromised
Solution Approach 1:
The system uses an inert flush gas to create an inert environment in the sampling chamber during engine operation. This inert atmosphere prevents contamination of the crevice fluid sample while allowing sampling to occur during normal engine operation, thus maintaining both minimal disruption and sample purity.
Solution Approach 2:
The inert flush gas acts as an intermediary that allows sampling during engine operation without compromising sample purity. It provides a clean environment that prevents contamination while enabling the sampling process to occur during normal engine operation with minimal disruption.
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
Enables the collection and analysis of sufficient fluid samples with minimal impact on engine performance, providing insights into crevice fluid composition and aiding in emissions control and pre-ignition issues.
Implementation Method 1
a relief valve and a piloted check valve to collect micro-samples near the top-dead-center of the compression stroke
Implementation Method 2
a relief valve and a piloted check valve to collect micro-samples near the top-dead-center of the compression stroke
Implementation Method 3
an inert flush gas for sample purity
Data Source
AI summary
A system and method for sampling fluid from a top land piston crevice of a reciprocating piston engine. Access into the crevice is via a length of tubing inserted into a bore through the piston wall. Two valves, first a relief valve and then a piloted check valve, operate together to capture a sample of fluid from the crevice at a time just before TDC of the piston on its compression stroke. The sampled fluid flows from the check valve into a sample container. The valves further cooperate to close fluid communication from the crevice after a sample is taken, which allows the engine to operate normally.