Fuel Injector Balancing via Inter-Injection Timing Adjustment
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Solution Overview
Problem
Existing fuel injector calibration methods face challenges in accurately balancing fuel delivery across multiple injectors due to piece-to-piece variability and aging, leading to reduced fuel economy, increased emissions, and engine efficiency issues, especially in dual injector systems where the number of injectors increases the likelihood of errors in computation of average inter-injection pressure.
Innovation Solution
The method involves adjusting injection timing to extend inter-injection periods by advancing or retarding the timing of fuel injections, dividing injectors into sets to calculate pressure drops based on average fuel rail pressures, and selectively including certain injection events for improved balancing, thereby reducing errors caused by Gaussian noises and pressure oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of fuel injectors is increased in dual injector systems, then fuel delivery capability is improved, but injector variability and computation errors increase
Solution Approach 1:
The patent segments the fuel injection measurement process by dividing injectors into groups and performing separate pressure drop measurements for each group. This allows accurate characterization of individual injector performance even in systems with many injectors, preventing computation errors from accumulating across the entire system.
Solution Approach 2:
The patent performs preliminary injector balancing measurements during engine build-up or before production, establishing baseline transfer functions for each injector. This preliminary characterization enables accurate fuel delivery control throughout the injector lifecycle, accommodating piece-to-piece variability and aging effects.
2Productivity
If inter-injection period is shortened due to increased number of injectors, then injection frequency is improved, but pressure calculation errors increase
Solution Approach 1:
The patent segments the measurement process by grouping injectors and performing separate pressure drop measurements for each group during the balancing procedure. This segmentation allows sufficient measurement time for each group despite high overall injection frequency, maintaining pressure calculation accuracy.
Solution Approach 2:
The patent performs partial injector balancing by focusing measurements on specific injector groups at different engine speeds, rather than attempting to measure all injectors simultaneously at maximum frequency. This partial approach ensures accurate pressure calculations for each measured group.
3Ease of operation
If average inter-injection pressure is used to estimate fuel rail pressure drop, then measurement simplicity is improved, but errors from Gaussian noises and pressure oscillations increase
Solution Approach 1:
The patent performs preliminary measurements of fuel rail pressure under controlled conditions to establish baseline characteristics and filter coefficients. These preliminary actions enable accurate pressure drop estimation during actual operation by compensating for Gaussian noises and pressure oscillations through pre-characterized system behavior.
Solution Approach 2:
The patent implements feedback mechanisms where measured pressure drops are used to update and refine the transfer functions for each injector. This continuous feedback loop compensates for measurement errors from noises and oscillations, improving accuracy over time while maintaining operational simplicity.
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 accuracy of fuel injector balancing, leading to improved fuel efficiency and emissions quality by ensuring consistent fuel delivery across all injectors, reducing errors in pressure calculations, and maintaining engine performance.
Implementation Method 1
A fuel injector may be a direct fuel injector (DI) for delivering fuel directly to a combustion chamber of an engine or a port fuel injector (PFI) for delivering fuel to an intake port of a combustion chamber
Implementation Method 2
fuel rail pressure drop across each injector to correct each injector's transfer function
Implementation Method 3
average inter-injection pressure is used to estimate the fuel rail pressure drop across each injector
Data Source
AI summary
Methods and systems are provided for balancing fuel delivery amongst all engine fuel injectors. In one example, a method may include selectively adjusting an injection timing of one or more fuel injectors of a plurality of fuel injectors to increase an inter-injection period between two consecutive fuel injections in response to a request to balance amounts of fuel injected by the plurality of fuel injectors.