Combustion Chamber Pressure Oscillation Sensing for Cylinder Gas Mass
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Solution Overview
Problem
Existing methods for determining the mass of gas drawn into an internal combustion engine's combustion chamber are inaccurate, complex, and require expensive and varied instrumentation, failing to account for cylinder-specific differences and introducing estimation errors.
Innovation Solution
A method using a single pressure sensor in the combustion chamber to measure pressure oscillations, determine frequency, and apply a model to calculate gas mass, considering cylinder-specific parameters and residual gas, without complex signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow meters are used to measure gas mass, then measurement capability is provided, but cost increases and measurement precision varies significantly between sensors
Solution Approach 1:
The patent replaces mechanical flow meters with a pressure-based acoustic method. By measuring pressure oscillations and their frequencies in the combustion chamber, the system determines gas mass without requiring expensive flow sensing instrumentation. This substitution of measurement principle resolves the contradiction by eliminating complex mechanical sensors while maintaining measurement capability.
2Measurement precision
If signal processing techniques are applied to estimate gas mass, then measurement capability is enhanced, but complexity and time consumption increase
Solution Approach 1:
The patent extracts only the essential frequency information from pressure oscillations to determine gas mass, rather than applying comprehensive signal processing techniques. By focusing specifically on frequency measurement and using it directly in the gas mass calculation formula, the method achieves accurate estimation while minimizing processing complexity and time requirements.
3Measurement precision
If pressure resonance frequency is estimated using Fourier transform, then frequency analysis is performed, but measurement precision is insufficient and computational complexity increases
Solution Approach 1:
The patent uses simple frequency counting methods rather than computationally intensive Fourier transforms. By implementing straightforward frequency measurement techniques that are faster and less complex, the system achieves sufficient precision for gas mass determination while significantly reducing processing time and computational resources required.
4Productivity
If cylinder-averaged gas mass estimation is performed, then overall engine performance is monitored, but individual cylinder control capability is lost
Solution Approach 1:
The patent applies segmentation by determining gas mass for each individual cylinder separately using pressure oscillation measurements from each cylinder's combustion chamber. This cylinder-by-cylinder approach enables precise individual control while maintaining overall engine management efficiency, resolving the contradiction between averaged monitoring and specific control capability.
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
Accurately and reliably determines gas mass cylinder-by-cylinder and cycle-by-cycle, enhancing combustion control and reducing pollutant emissions, with simpler and cost-effective instrumentation.
Implementation Method 1
The invention relates to a method for determining the mass of gas drawn into at least one cylinder of an internal combustion engine, said at least one cylinder being equipped with a pressure sensor, in which the following steps are carried out: a. The pressure of said gas in said at least one cylinder is measured by means of said pressure sensor; b. The oscillations of said gas pressure are determined from said pressure measurement in said at least one cylinder; c. An instantaneous frequency of said pressure oscillations f is determined
Data Source
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AI summary
The present invention relates to a method for determining the mass of gas drawn into at least one combustion chamber based on the measurement of the pressure within the combustion chamber. The method involves determining the oscillation frequency (OSC P) and then using the latter in a model of the combustion chamber (2).