Dual Smoothing Fuel Pressure Control for Engine Air-Fuel Accuracy
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Solution Overview
Problem
Existing fuel injection control methods for in-cylinder injection-type internal combustion engines face challenges in achieving high accuracy for air-fuel ratio control due to variations in fuel pressure, particularly in distinguishing between transient and steady states.
Innovation Solution
Implementing a dual smoothing process for detected fuel pressure, where the first smoothing process uses a moderating calculation and the second smoothing process calculates an average value over specific intervals, allowing selection of the appropriate smoothing method based on the engine's operating state to optimize fuel injection control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single smoothing process is used on detected fuel pressure, then the control system is simple, but the accuracy in air-fuel ratio control deteriorates during different engine operating states
Solution Approach 1:
The patent divides the fuel pressure smoothing process into two separate smoothing processes (first smoothing and second smoothing) with different smoothing degrees. The first smoothing process applies a higher degree of smoothing while the second smoothing process applies a lower degree of smoothing. This segmentation allows the system to handle different engine operating states (transient and steady states) with appropriate smoothing levels, thereby improving air-fuel ratio control accuracy without excessive complexity.
Solution Approach 2:
The patent dynamically switches between the first smoothing process and the second smoothing process based on the detected engine operating state. When a transient state is detected, the system switches to the second smoothing process with lower smoothing degree for faster response. When a steady state is detected, the system switches to the first smoothing process with higher smoothing degree for better stability. This dynamic adaptation resolves the contradiction between simplicity and accuracy.
2Stability of the object's composition
If a high degree of smoothing is applied to fuel pressure detection, then stability in fuel injection control is improved, but responsiveness to transient fuel pressure changes deteriorates
Solution Approach 1:
The patent implements dynamic switching between two smoothing processes based on engine operating state detection. During transient states, the system activates the second smoothing process with lower smoothing degree to maintain fast response speed. During steady states, the system activates the first smoothing process with higher smoothing degree to ensure injection stability. This dynamic approach resolves the contradiction between stability and responsiveness.
Solution Approach 2:
The patent changes the smoothing parameter (smoothing degree) based on the engine operating state. The system detects whether the engine is in a transient or steady state and accordingly selects the appropriate smoothing degree. This parameter change allows the system to optimize both stability and responsiveness for different operating conditions, resolving the contradiction between these two requirements.
3Speed
If fuel pressure variations are not smoothed, then responsiveness to actual fuel pressure changes is maintained, but the accuracy in air-fuel ratio control deteriorates due to noise and fluctuations
Solution Approach 1:
The patent segments the smoothing operation into two distinct processes with different smoothing degrees. The second smoothing process (lower smoothing degree) preserves more of the original fuel pressure signal characteristics, maintaining responsiveness while reducing noise. The first smoothing process (higher smoothing degree) provides additional noise filtration when stability is prioritized. This segmentation allows the system to achieve both responsiveness and accuracy under different operating conditions.
Solution Approach 2:
The patent changes the smoothing parameter based on engine operating state to balance responsiveness and accuracy. During transient states, the system uses lower smoothing degree to maintain responsiveness to actual fuel pressure changes. During steady states, the system uses higher smoothing degree to filter out noise and fluctuations. This adaptive parameter change resolves the contradiction between responsiveness and control accuracy.
Data Source
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AI summary
A fuel injection control method for an internal combustion engine is provided. The internal combustion engine includes a fuel pump (38) that pressure-feeds fuel, a fuel injection valve (19) that injects the fuel pressure-fed by the fuel pump directly into a cylinder of the internal combustion engine (1), and a fuel pressure detection device (45) that detects a pressure of the fuel pressure-fed by the fuel pump. The fuel injection control method executes a first smoothing process (S3) of performing a smoothing process on a detected fuel pressure by first smoothing, a second smoothing process (S4) of performing a smoothing process on the detected fuel pressure by second smoothing different from the first smoothing, and a selection process (S5) of selecting, based on an operating state of the internal combustion engine, whether to execute fuel injection control (S6, S7) based on a first detected fuel pressure smoothed by the first smoothing process or fuel injection control (S8, S9) based on a second detected fuel pressure smoothed by the second smoothing process.