In-Cylinder Pressure Estimation Using Two-Point Sampling
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Solution Overview
Problem
Conventional internal combustion engine control apparatuses face difficulties in accurately estimating in-cylinder pressure due to complex calculation formulas and high computation loads, making it challenging to perform precise engine control.
Innovation Solution
An internal combustion engine control apparatus that includes means for acquiring heat release amount information, combustion ratio information, and relationship information to estimate in-cylinder pressure, using methods such as the Weibe function and ion detection, allowing for accurate pressure estimation and subsequent control functions like ignition timing and air-fuel ratio adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the conventional calculation formula for in-cylinder pressure is used, then measurement precision is improved, but device complexity and computation load increase
Solution Approach 1:
The patent extracts the essential combustion information from complex pressure calculations by using only two specific crank angle points (top dead center and bottom dead center). This extraction approach obtains sufficient in-cylinder pressure estimation data without requiring the full complex calculation formula, thereby reducing computational complexity while maintaining measurement precision.
Solution Approach 2:
The patent segments the in-cylinder pressure measurement problem into two discrete sampling points (top dead center and bottom dead center) rather than requiring continuous high-speed sampling. This segmentation allows the ECU to estimate pressure at critical moments without the computational burden of continuous measurement, resolving the contradiction between precision and complexity.
2Measurement precision
If high-speed sampling is conducted to calculate in-cylinder pressure with high accuracy, then measurement precision is improved, but productivity and response time worsen due to heavy computation load
Solution Approach 1:
The patent divides the pressure measurement task into two discrete sampling instances at critical crank angles rather than continuous high-speed sampling. This segmentation reduces the number of calculations required per engine cycle, thereby improving ECU processing speed and productivity while maintaining sufficient measurement precision for control purposes.
Solution Approach 2:
The patent applies partial action by sampling at only two critical points (top dead center and bottom dead center) rather than performing excessive continuous sampling. This partial measurement approach provides sufficient information for pressure estimation and control decisions without the computational overhead of exhaustive measurement, thus improving processing speed.
3Ease of operation
If conventional technology uses only two data points for pressure estimation, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The patent applies preliminary action by selecting and sampling at the two most critical crank angle points (top dead center and bottom dead center) where pressure information is most valuable for combustion control. This preliminary selection of optimal measurement points ensures that the simple two-point method achieves sufficient precision for practical engine control applications.
Solution Approach 2:
The patent applies local quality by concentrating measurement efforts at specific critical locations in the combustion cycle (top dead center and bottom dead center) rather than uniform sampling throughout. This localized measurement approach maximizes the information obtained from just two data points, achieving adequate precision where it matters most for control decisions.
Data Source
AI summary
An internal combustion engine control apparatus includes an in-cylinder pressure sensor for detecting in-cylinder pressure. A combustion start time and combustion end time, which are parameters serving as control indexes for an internal combustion engine, are determined in accordance with ignition timing. Information about a heat release amount is acquired in accordance with the in-cylinder pressures that are measured at two points by the in-cylinder pressure sensor. The in-cylinder pressure is estimated in accordance with a relationship among the heat release amount information, control index parameters, and in-cylinder pressure.