GDI Injector Flow Deviation Correction via Cylinder Pressure Drop
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Solution Overview
Problem
Gasoline direct injection (GDI) engines face deviations in air-fuel ratios between cylinders due to manufacturing tolerances and injector coking/aging, leading to increased particulate numbers, which existing technologies have not adequately addressed.
Innovation Solution
A method and system that adjust the injection correction factor for each cylinder based on relative pressure drop amounts and an average of injection correction factors to correct deviations in fuel injection amounts, using a controller with a learning unit and detection unit to minimize fuel injection discrepancies between cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If high pressure injection system (350 bar) is applied to reduce particulate substances, then fuel injection precision is improved, but deviation of air-fuel ratio between cylinders increases due to manufacturing tolerance and injector coking/aging
Solution Approach 1:
The patent changes the parameter of injection correction factor from a uniform value to cylinder-specific variable values. By calculating individual correction factors for each cylinder based on pressure drop measurements, the system compensates for manufacturing tolerances and injector degradation, thereby maintaining air-fuel ratio consistency while operating at high injection pressures.
Solution Approach 2:
The patent implements a feedback mechanism where pressure drop amounts are continuously measured by fuel pressure sensors, compared against target values, and used to adjust injection correction factors. This closed-loop feedback system dynamically compensates for injector deviations and maintains consistent air-fuel ratios across all cylinders despite high pressure operation.
2Manufacturing precision
If injection correction factor is adjusted to correct fuel injection deviation, then air-fuel ratio consistency is improved, but system complexity increases due to additional correction calculations
Solution Approach 1:
The patent enables the injection system to self-diagnose and self-correct by using its own pressure sensors to measure pressure drops and automatically calculate correction factors. The ECU performs the correction calculations using existing sensor data without requiring external diagnostic equipment or complex additional hardware, thereby limiting the increase in system complexity.
Solution Approach 2:
The patent performs preliminary correction by calculating target pressure drop amounts and comparing them with actual measurements before final injection execution. This preliminary calculation of correction factors allows the system to pre-compensate for deviations, simplifying the real-time control requirements during actual injection operations.
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 improves combustion stability and reduces particulate numbers by accurately adjusting fuel injection amounts, thereby addressing the deviations and enhancing engine performance.
Implementation Method 1
calculating a relative pressure drop amount for each cylinder from a detected pressure drop amount for each cylinder, which is detected in each cylinder by a fuel pressure sensor
Data Source
AI summary
A method for correcting a deviation of static flow rates of GDI injectors is provided. The method includes calculating a target pressure drop amount for each cylinder and a relative pressure drop amount for each cylinder from a detected pressure drop amount. An injection correction factor for each cylinder is primarily adjusted by comparing the relative pressure drop amount for each cylinder, with an average of relative pressure drop amounts of all cylinders. The injection correction factor is then secondarily adjusted by comparing an average of injection correction factors of all cylinders with 1.