Engine Fuel Pressure Pulsation Prediction Model
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Solution Overview
Problem
Existing control systems for internal combustion engines struggle to accurately control fuel injection amounts due to fuel pressure pulsation, which is influenced by multiple factors and cannot be effectively managed by considering only the engine's rotating speed.
Innovation Solution
A control device that includes an electronic control unit capable of calculating amplitudes, vibration frequencies, and initial phases of waves caused by various factors within the low-pressure fuel passage, using a model formula to predict fuel pressure values at arbitrary crank angles, thereby synthesizing the waves and adjusting fuel injection accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fuel injection amounts are controlled on the basis of detection value of fuel pressure sensor, then fuel injection control can be implemented, but fuel injection amounts become uncontrollable due to fuel pressure pulsation
Solution Approach 1:
The patent introduces a fuel pressure prediction value as an intermediary between the actual fuel pressure sensor readings and the fuel injection control. This predicted value, calculated based on engine operating conditions and pulsation characteristics, mediates the control process to eliminate the harmful effect of pressure pulsation while maintaining ease of control implementation
Solution Approach 2:
The patent creates a copy or model of the fuel pressure behavior through prediction calculations based on engine operating conditions. This copied pressure information, which excludes pulsation effects, is then used for control purposes, allowing accurate fuel injection control without being affected by the actual pulsating pressure readings
2Device complexity
If correction values are defined in advance for every rotating speed without using actual fuel pressure value, then pulsation control is simplified, but fuel injection amount control becomes inappropriate due to insufficient consideration of pulsation factors
Solution Approach 1:
The patent changes the parameters used for control from simple engine rotating speed to a comprehensive set including engine rotating speed, load, and calculated fuel pressure prediction values. This parameter transformation enables precise fuel injection control while maintaining reasonable system complexity through systematic calculation approaches
3Ease of operation
If only engine rotating speed is considered for pulsation correction, then control is simplified, but fuel injection amount control becomes inappropriate due to insufficient accuracy
Solution Approach 1:
The patent segments the fuel pressure pulsation into distinct components based on different sources (injection valve operations, pump operations). By calculating correction values for each segmented pulsation source separately and combining them, the system achieves high prediction accuracy while maintaining operational simplicity through modular calculation
Data Source
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AI summary
A control device for an internal combustion engine (10) is equipped with an electronic control unit (41). The electronic control unit (41) is configured to: i) calculate amplitudes of respective waves, respectively, originating from a plurality of factors that causes fuel pressure pulsation within a low-pressure fuel passage (25), vibration frequencies of the respective waves within a crank angle range of 360 degrees, initial phases of the respective waves, and central fuel pressure values of the respective waves; and ii) predict a fuel pressure value at an arbitrary crank angle according to a model formula showing a synthesized wave obtained by synthesizing the respective waves, on a basis of the amplitudes, the vibration frequencies, the initial phases, and the central fuel pressure values of the respective waves calculated.