Variable Compression Engine Control via Crankshaft Irregularity
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Solution Overview
Problem
Reciprocating piston engines with variable compression ratios face challenges in accurately diagnosing and controlling rotational irregularities, which affect engine performance due to varying dynamic forces and frictional influences across cylinders.
Innovation Solution
A method and system that determine rotational irregularity parameters of a crankshaft to calculate compression ratio parameters, allowing for the adjustment of compression ratios and piston rod lengths to diagnose and control engine performance by measuring and varying these parameters within specific crank angle regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If compression ratio is varied to adapt to different demands, then engine functionality and efficiency are improved, but rotational irregularity and diagnostic difficulty increase
Solution Approach 1:
The system continuously monitors rotational irregularity parameters and feeds this information back to the control unit, which adjusts compression ratio accordingly. This closed-loop feedback mechanism enables real-time diagnosis and adaptive control, resolving the contradiction between adaptability and diagnostic difficulty.
Solution Approach 2:
The patent replaces traditional mechanical diagnostic methods with electronic sensing and computational analysis of rotational irregularity parameters. By using sensors and control units to detect and analyze rotational variations, the system achieves precise diagnosis without complex mechanical measurement apparatus.
2Measurement precision
If rotational irregularity measurement is used to determine compression ratio, then diagnostic precision is improved, but system complexity increases
Solution Approach 1:
The control unit serves multiple functions: it manages compression ratio adjustment, monitors rotational irregularity, performs diagnostic analysis, and controls engine operation. By consolidating these functions into a single multi-functional control unit, the system achieves high measurement precision without proportionally increasing overall system complexity.
Solution Approach 2:
The system uses the engine's own rotational motion as the measurement source, eliminating the need for separate diagnostic equipment. The rotational irregularity naturally occurring during engine operation is directly utilized for compression ratio determination, making the system self-diagnostic and reducing external complexity.
3Productivity
If piston rod length is adjusted to change compression ratio, then engine efficiency is improved, but manufacturing and assembly complexity increase
Solution Approach 1:
The piston rod length adjustment mechanism transforms the static piston rod into a dynamic, adjustable component. This allows the compression ratio to be varied during operation or maintenance, improving engine efficiency across different operating conditions while maintaining manufacturing feasibility through standardized adjustment mechanisms.
Solution Approach 2:
The system enables change in the geometric parameter of piston rod length to optimize engine performance. By providing adjustable piston rod lengths, the engine can adapt compression ratio to match different fuel types, operating conditions, and efficiency requirements, balancing manufacturing complexity with performance gains.
Data Source
AI summary
The invention relates to a method for diagnosing and/or controlling a reciprocating engine having a variable compression ratio, wherein the method comprises the working steps: determining (S30) a first value (U1,1, U1,2; Δ1) of a rotational irregularity parameter of a crankshaft (1) of the reciprocating engine; and determining (S60) a value of a compression ratio parameter for the reciprocating engine based on said first rotational irregularity parameter value.