Injection Quantity Equalization via Pressure Differential Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for injection quantity equalization in internal combustion engines with common rail systems lack robustness, particularly in cases of valve coking or aged valves, leading to unreliable fuel distribution and increased emissions and consumption.
Innovation Solution
A method that determines injection quantity differences between cylinders by statistically analyzing pressure values before and after fuel injection, using a common pressure sensor to ensure accurate pressure differential calculations, and adjusts valve control periods based on these differences to achieve reliable equalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common pressure pipe is used to supply fuel to multiple cylinders, then the system structure is simplified and fuel distribution is easier to control, but injection quantity differences between cylinders occur due to pressure losses and valve variations
Solution Approach 1:
The system uses a pressure sensor to continuously monitor the pressure in the common pressure pipe and feeds this information back to the control unit. The control unit calculates the actual injection quantity for each cylinder based on the pressure change before and after injection, and adjusts the injection duration accordingly to compensate for pressure losses and achieve equal injection quantities across all cylinders.
Solution Approach 2:
The control unit dynamically adjusts the injection duration parameter for each cylinder based on the measured pressure changes. By changing the injection duration parameter individually for each cylinder, the system compensates for the pressure losses that occur in the common pressure pipe and ensures that each cylinder receives the intended injection quantity.
2Manufacturing precision
If pressure values are recorded to determine injection quantity differences, then injection equalization can be achieved, but measurement errors and transient disturbances affect the accuracy of pressure differential calculations
Solution Approach 1:
The control unit records pressure values before injection and after injection for each cylinder, creating a baseline and an endpoint measurement. By performing these measurements in advance and at the appropriate time points, the system can accurately calculate the pressure differential caused by injection while excluding transient disturbances that occur during the injection process itself.
Solution Approach 2:
The system uses the recorded pressure values to calculate the actual injection quantity and feeds this information back to adjust the injection duration. This feedback mechanism allows the system to compensate for measurement errors and transient disturbances by continuously monitoring and adjusting based on the actual pressure changes observed.
3Measurement precision
If analog pressure values are converted to digital values for processing, then control accuracy can be improved, but conversion errors and signal discontinuities may occur
Solution Approach 1:
The system replaces the purely analog pressure measurement and control mechanism with a digital processing system. The pressure sensor output is converted to digital values, processed by the control unit, and used to adjust the injection duration. This substitution of mechanical/analog processing with electronic/digital processing improves precision and reliability while enabling more sophisticated error correction and signal processing.
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
This approach enhances the robustness of injection quantity equalization, ensuring accurate fuel distribution and reducing emissions and consumption by discarding measurements affected by transient disturbances and using high-resolution digital signals for precise pressure value recording.
Implementation Method 1
several chronologically consecutive first pressure values which are generated before fuel injection into the respective cylinder and several chronologically consecutive second pressure values which are generated after fuel injection into the respective cylinder are recorded in the pressure pipe
Data Source
Figure 1~2
Figure 3A~3B
Figure 4
AI summary
The consecutive pressure values of pressure tube (14) are acquired before fuel injection into cylinder for all cylinders (2-5). The consecutive pressure values of pressure tubes after the injection of fuel into cylinder are acquired for each cylinder. The statistical analysis of acquired pressure values is performed. The pressure difference value of cylinder is determined based on acquired pressure values, when the pressure values satisfy preset statistical property. The fuel injection quantity difference of cylinders is determined as function of pressure difference value. An independent claim is included for device for determining injection quantity difference of cylinders in internal combustion engine.