Variable Compression Engine Control via Magnetic Piston Sensing
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Solution Overview
Problem
Existing engine systems with variable compression devices face challenges in accurately adjusting the compression ratio due to difficulties in acquiring the piston rod's position, leading to instability in control.
Innovation Solution
An engine system equipped with a detection device that outputs positional information of the piston, allowing a position acquisition device to accurately determine the piston's position, which is then used by a control unit to adjust the pressure in a fluid chamber, ensuring precise control of the compression ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a compression adjustment device is provided to change the compression ratio by moving the piston rod using hydraulic pressure, then the engine can adapt to both liquid fuel and gas fuel operation, but the control device cannot accurately acquire the position of the piston rod leading to imprecise compression ratio adjustment
Solution Approach 1:
The patent replaces mechanical position sensing methods with a magnetic field-based detection system. A detection target with magnetic members is provided on the piston, and a magnetic sensor on the cylinder liner detects its position through magnetic field interaction, eliminating the need for direct mechanical contact or complex mechanical sensing mechanisms.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the moving piston and the stationary sensor. The magnetic field penetrates the cylinder liner wall to transmit position information from the piston to the sensor without requiring physical contact or openings in the cylinder liner.
2Measurement precision
If the detection device is provided inside the cylinder liner to detect piston position, then accurate position information can be acquired, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical position detection mechanisms with a magnetic field-based system. The magnetic sensor detects the position of magnetic members on the piston through the cylinder liner wall, eliminating the need for mechanical linkages, contact sensors, or complex signal transmission systems inside the cylinder.
Solution Approach 2:
The magnetic detection system serves multiple functions: it detects piston position, determines crank angle, and provides feedback for compression ratio control, all through a single integrated sensing mechanism that operates through the cylinder liner wall.
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 solution enables accurate and stable control of the variable compression device by continuously monitoring and matching the piston's position to a target, enhancing the engine's operational efficiency.
Implementation Method 1
a magnetic sensor that outputs a signal in accordance with a change in the magnetic field as two detection targets move
Implementation Method 2
a fluid chamber in which a piston rod connected to a piston is moved in a direction to increase a compression ratio by a pressurized working fluid being supplied thereto
Data Source
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AI summary
The engine system (100) includes: a variable compression device (6, 7 and 8) including a fluid chamber (R3) in which a piston rod (6) connected to a piston (4) is moved in a direction to increase a compression ratio by a pressurized working fluid being supplied thereto; a detection device (400) that outputs a signal including positional information of the piston; and a position acquisition device (300) that acquires a position of the piston based on the signal.