Fuel Injector Pressure Drop Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fuel injectors of the same type can inject slightly different amounts of fuel due to manufacturing material differences and component tolerances, leading to inaccuracies in fuel injection, which existing methods partially address by estimating fuel pressure drops but still require improvement.
Innovation Solution
Estimating fuel pressure drops in a fuel rail by analyzing average pressures before and after injection, and the slopes of pressure changes during inter-injection periods to adjust subsequent fuel injections, compensating for thermal changes and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fuel injection amount is estimated using only average fuel pressure before and after injection, then the estimation process is simple, but the accuracy of fuel injection amount is insufficient due to unaccounted thermal changes
Solution Approach 1:
The patent measures fuel pressure during the inter-injection period before the actual fuel injection to capture thermal changes that occur prior to injection. This preliminary pressure measurement allows the system to compensate for thermal effects on fuel density before the injection event, improving the accuracy of fuel injection amount estimation without adding complex hardware
Solution Approach 2:
The patent uses measured fuel pressure changes during inter-injection periods to calculate compensation values that are applied to subsequent fuel injection commands. This feedback mechanism continuously adjusts for thermal drift in the fuel rail, ensuring accurate fuel delivery despite temperature variations in the fuel system
2Measurement precision
If fuel pressure changes during inter-injection periods are compensated, then fuel injection accuracy is improved, but the calculation complexity increases
Solution Approach 1:
The patent focuses on measuring and compensating only for pressure changes that occur during specific inter-injection periods when no fuel is being injected to any cylinder. By isolating and compensating for thermal drift during these specific time windows, the system achieves accurate compensation without the complexity of continuously monitoring and calculating all pressure changes throughout the engine cycle
3Manufacturing precision
If manufacturing tolerances and material differences are addressed through tighter tolerances, then injector consistency improves, but manufacturing cost and complexity increase
Solution Approach 1:
The patent implements a self-calibration capability where each fuel injector is automatically tested and calibrated in-place during engine operation. The system measures the actual fuel delivery of each injector and automatically adjusts injection parameters to compensate for manufacturing variations, eliminating the need for complex precision manufacturing while achieving consistent injector performance
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 reduces errors in fuel injection amounts by accounting for pressure changes during inter-injection periods, ensuring closer alignment with requested fuel quantities and compensating for thermal effects in real-time operation.
Implementation Method 1
These sloped pressure changes that take place during the inter-injection period may be related to thermal gain/loss in the fuel pressurized within the fuel rail
Data Source
AI summary
Methods and systems for adjusting fuel injector operation according to changes in fuel pressure during inter-injection periods are described. The inter-injection period may be before and after fuel is injected to an engine. The methods and systems described herein may be suitable for direct and port fuel injectors.