Variable Compression Ratio Engine Diagnosis via Magnetic Piston Position
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Solution Overview
Problem
Existing variable compression ratio apparatuses face challenges in accurately diagnosing operating conditions due to vibration and noise generated by engine operation, which can lead to unitability issues and combustion abnormalities.
Innovation Solution
An apparatus and method that includes a piston, a detector to determine the piston's position, and a controller that approximates the position signal to a second-order expression through regression analysis to diagnose the variable compression ratio apparatus, determining its defectiveness based on extremum values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the compression ratio is increased to improve thermal efficiency, then fuel efficiency is improved, but abnormal combustion and knocking may occur causing damage to the engine
Solution Approach 1:
The patent implements a variable compression ratio mechanism that dynamically adjusts the compression ratio based on engine operating conditions. The connecting rod length is可变 through a control system that moves the crosshead, allowing the compression ratio to be optimized for different loads and speeds, preventing abnormal combustion while maintaining fuel efficiency
Solution Approach 2:
The patent changes the compression ratio parameter according to engine operating conditions. By adjusting the connecting rod length to vary the compression ratio, the system optimizes thermal efficiency at low loads while preventing knocking and abnormal combustion at high loads, thus resolving the contradiction between fuel efficiency and reliability
2Power
If the ignition timing is advanced to improve thermal efficiency, then power output is improved, but abnormal combustion is generated causing engine damage
Solution Approach 1:
The variable compression ratio system dynamically adjusts compression ratio based on ignition timing and load conditions. When ignition timing is advanced for power improvement, the system can simultaneously adjust compression ratio to prevent abnormal combustion, resolving the contradiction between power output and reliability
3Use of energy by moving object
If the compression ratio is varied to improve fuel efficiency, then fuel economy is improved, but diagnosis accuracy deteriorates due to vibration and noise
Solution Approach 1:
The patent introduces a magnetic detector as an intermediary measurement device that detects piston position through magnetic field changes rather than direct mechanical contact. This intermediary approach allows accurate position detection despite vibration and noise from engine operation and combustion, maintaining diagnosis accuracy while enabling variable compression ratio for fuel efficiency improvement
Solution Approach 2:
The patent replaces mechanical position detection methods with magnetic field-based detection. The magnetic detector measures piston position through magnetic flux changes, eliminating the need for direct mechanical contact and sensors that would be affected by vibration and combustion noise, thus maintaining measurement precision while enabling variable compression ratio operation
4Loss of information
If a detector is installed to monitor piston position for diagnosis, then diagnosis capability is improved, but the system becomes sensitive to vibration and combustion noise
Solution Approach 1:
The patent replaces mechanical position sensing with magnetic field detection. The magnetic detector measures piston position through changes in magnetic flux caused by the magnetic marker on the piston, eliminating sensitivity to mechanical vibration and combustion noise while maintaining diagnosis capability
Solution Approach 2:
The magnetic field acts as an intermediary between the piston and the detection system. The magnetic detector senses position through magnetic flux changes rather than direct mechanical interaction, filtering out vibration and noise while preserving diagnostic information
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 accurate diagnosis of the variable compression ratio apparatus, distinguishing between normal and defective states, thereby improving engine performance and preventing output deterioration.
Implementation Method 1
the magnetic detector may be configured to determine a position signal of the piston from a variation of a magnetic signal in accordance with a connecting rod bushing provide on the piston
Data Source
AI summary
An apparatus for diagnosing an engine including a variable compression ratio apparatus according to an exemplary embodiment of the present invention, may include a piston configured to reciprocally move in a cylinder of the engine, a detector configured to determine a position of the piston, a variable compression ratio apparatus configured to adjust a moving range of the piston, and a controller configured to determine whether the variable compression ratio apparatus is defective based on a position signal of the piston determined by the detector.