Fuel Injection Timing Control via Pressure Wave Compensation
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Solution Overview
Problem
Fuel injection systems in internal combustion engines face challenges in precisely metering fuel due to hydraulic delays caused by injection valve mechanics, which affect emission standards compliance and efficiency.
Innovation Solution
A method where a control unit adjusts the timing of the injection process by accounting for mechanical delays, fuel pressure, and previous injection data, using a three-dimensional characteristic diagram and temperature factors to calculate a correction value that compensates for pressure waves in the injector feed line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hydraulic delays caused by injection valve mechanics are compensated using offline hybrid test bench measurements, then fuel injection timing precision is improved, but device complexity and measurement cost increase
Solution Approach 1:
The patent extracts the correction value determination from complex offline hybrid test bench measurements and implements it within the control unit using readily available sensor data (fuel pressure, temperature, injection quantity). This separates the essential correction function from the complex measurement infrastructure, maintaining precision while reducing device complexity.
Solution Approach 2:
The control unit determines correction values autonomously using its own internal sensors and processing capabilities, rather than relying on external offline test bench measurements. The system serves itself by utilizing existing operational data to compensate for hydraulic delays, eliminating the need for separate complex measurement systems.
2Measurement precision
If correction values are determined using multiple input variables (fuel pressure, injection quantity, time interval) and three-dimensional characteristic diagrams, then fuel injection timing precision is improved, but computational complexity increases
Solution Approach 1:
The patent pre-calculates and stores three-dimensional characteristic diagrams containing correction values for various combinations of fuel pressure, injection quantity, and time interval during system setup or calibration. During operation, the control unit simply retrieves the appropriate correction value from these pre-computed tables based on current sensor readings, avoiding complex real-time calculations while maintaining high precision.
3Object-affected harmful factors
If fuel pressure waves in the injector feed line are compensated, then emission standards compliance is improved, but production tolerances for injectors become more stringent
Solution Approach 1:
The patent compensates for fuel pressure wave effects by dynamically adjusting the injection timing based on measured fuel pressure, temperature, and injection quantity parameters. The control unit calculates correction values that counteract the variable delays caused by pressure waves, allowing standard production tolerances to be maintained while achieving consistent emission compliance across all injectors.
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 allows for more precise fuel injection timing, improving emission standards compliance and enabling larger production tolerances for injectors, thus reducing costs.
Implementation Method 1
One of these delays is a hydraulic delay which is due to the fact that an injector requires time to move its needle into a position which permits fuel to be injected through the valve
Implementation Method 2
the control unit also takes into account a correction value in the determination of the time of the outputting of the instruction for starting the injection process, which correction value describes the fuel pressure in the injector feed line
Data Source
AI summary
A method for regulating a fuel injection system of an internal combustion engine includes outputting from a control unit an instruction to start an injection process of fuel through an injection valve, wherein during a determination of a time of the outputting of the instruction to start the injection process, the control unit takes into account delays caused by the mechanical system of the injection valve. Furthermore, during the determination of the time of the outputting of the instruction to start the injection process, the control unit also takes into account a correction value which describes the fuel pressure in the injector feed line.