Fuel Injector Balancing via Pressure Sampling
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Solution Overview
Problem
Existing fuel injector calibration methods are prone to errors due to pressure ringing and noise, leading to variability in fuel injection, which affects fuel economy, emissions, and engine efficiency.
Innovation Solution
A method that discards samples collected during pressure ringing and averages those from a quiet period after injector closure to accurately estimate fuel rail pressure changes, allowing for improved injector balancing by learning and adjusting fuel injector errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fuel rail pressure is sampled during and after injector closing to determine fuel injection amount, then measurement coverage is improved, but aliasing errors and resolution errors increase due to pressure ringing and noise
Solution Approach 1:
The system performs preliminary action by discarding pressure samples during the injection event and a threshold duration after injector closing, before averaging the remaining samples. This preliminary filtering of noisy data prevents aliasing errors from contaminating the measurement, allowing accurate fuel injection amount determination despite the presence of pressure ringing.
Solution Approach 2:
The invention extracts only the useful, non-noisy pressure samples from the complete sampling period. By removing (taking out) the problematic samples collected during injection and immediate post-injection periods when pressure ringing occurs, the system isolates the clean measurement data needed for accurate fuel mass calculation.
2Stability of the object's composition
If pressure samples are averaged to reduce noise, then signal stability is improved, but aliasing errors persist due to strong frequency content in the sampled signal
Solution Approach 1:
The system extracts only the clean, non-aliased pressure samples for averaging, excluding those collected during injection events and the immediate post-injection period when pressure ringing creates strong frequency content. This extraction of valid samples ensures that the average represents the true mean pressure without contamination from aliasing errors.
Solution Approach 2:
Before performing the averaging operation, the system preliminarily filters out problematic samples through discarding during injection and post-injection periods. This preliminary action ensures that only suitable samples are included in the average, preventing aliasing errors from affecting the final measurement accuracy.
3Productivity
If fuel injector calibration is performed without accounting for pressure ringing, then calibration speed is maintained, but fuel delivery variability increases between injectors
Solution Approach 1:
The calibration method incorporates preliminary filtering of pressure samples during the calibration process itself. By automatically discarding noisy samples during injection and post-injection periods before averaging, the system maintains calibration speed while achieving precise fuel delivery measurements, eliminating the need for separate manual filtering steps.
Solution Approach 2:
The system performs self-service calibration by automatically identifying and excluding noisy samples based on the injection timing and pressure signal characteristics. The calibration process itself generates the metadata needed to filter samples, eliminating the need for external intervention or complex additional hardware.
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 aliasing and resolution errors, enabling more accurate fuel injection volume estimation and balancing, thereby enhancing engine performance and efficiency.
Implementation Method 1
when the pintle moves inward, it compresses the fluid behind the injector, raising the fuel pressure
Implementation Method 2
When the pintle closes, its abrupt closing triggers a pressure oscillation (water hammer) that decays exponentially
Data Source
AI summary
Methods and systems are provided for improved injector balancing. In one example, fuel rail pressure samples collected during a noisy zone of injector operation are discarded while samples collected during a quiet zone are averaged to determine an injector pressure. The injector pressure is then used to infer injection volume, injector error, and update an injector transfer function.