Variable Compression Engine Control for Piston Ring Step Contact
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Solution Overview
Problem
In engines, the piston ring wear causes steps on the cylinder inner peripheral surface, leading to significant impacts when the piston reaches the top dead center position, affecting compression ratio and potentially damaging components.
Innovation Solution
An engine with a detector to signal contact between the piston ring and the cylinder liner step, and a compression ratio controller to adjust the piston's position to avoid the step, thereby preventing excessive wear and impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the top dead center position is moved toward a high compression ratio side to improve compression efficiency, then the compression ratio is improved, but the piston ring contacts the step formed by cylinder wear causing large impact
Solution Approach 1:
The patent applies dynamics by making the top dead center position variable rather than fixed. The compression ratio controller dynamically adjusts the top dead center position based on detection signals from the detector. When a step is detected, the controller moves the top dead center position to a location where the piston ring does not contact the step, thereby eliminating impact while maintaining optimal compression ratio through adaptive positioning.
Solution Approach 2:
The patent implements feedback through the detector-compression ratio controller system. The detector continuously monitors the cylinder inner peripheral surface for steps and sends detection signals to the compression ratio controller. The controller then adjusts the top dead center position based on this feedback, creating a closed-loop control system that prevents piston ring contact with steps and eliminates harmful impacts.
2Duration of action of moving object
If the engine operates for a long period allowing cylinder wear to occur, then the engine runs continuously, but steps form on the cylinder surface causing performance degradation
Solution Approach 1:
The patent applies preliminary action by detecting steps on the cylinder surface before they cause significant performance degradation. The detector identifies step formation early in the wear process, and the compression ratio controller proactively adjusts the top dead center position to prevent the piston ring from contacting the step. This preliminary intervention prevents further wear and maintains cylinder surface integrity over extended operation periods.
Solution Approach 2:
The patent implements self-service through the automated detection and adjustment system. The detector continuously monitors the cylinder surface condition, and the compression ratio controller automatically adjusts the top dead center position without external intervention. This self-monitoring and self-adjusting mechanism allows the engine to maintain optimal performance and prevent further wear automatically during prolonged operation.
3Object-affected harmful factors
If a detector and compression ratio controller are added to prevent piston ring contact with steps, then impact is reduced, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the compression ratio controller to perform multiple functions: it controls the top dead center position for compression ratio optimization, detects step formation through integrated sensing, and adjusts positioning to prevent piston ring contact. By combining detection and control functions in a single integrated system, the patent reduces overall device complexity while maintaining effective impact prevention.
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 solution effectively suppresses the formation of steps on the cylinder surface, reducing wear and impact, ensuring smoother operation and extending engine lifespan.
Implementation Method 1
a detector configured to output a detection signal in accordance with a contact between a step formed in an inner peripheral surface of the cylinder liner and the piston ring
Data Source
Figure 1
Figure 2~3
Figure 4(a)~5(d)
AI summary
Provided is an engine (100), including: a cylinder including a cylinder liner; a piston provided inside the cylinder liner; a piston ring provided on the piston; a contact detector (184) configured to detect a contact between a step formed in an inner peripheral surface of the cylinder liner and the piston ring; and a compression ratio controller (182) configured to control a top dead center position of the piston so that the piston ring at the top dead center position is located on a combustion chamber side with respect to the step when the contact is detected.