Diesel Injector Drift Detection via Alternating Pulse Patterns
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Solution Overview
Problem
Diesel engine fuel injector quantity drift leads to increased engine emissions, as the amount of fuel injected can deviate from nominal values over the engine's service life, making it challenging to detect and correct injector malfunctions, especially when the fuel is distributed across multiple injection pulses.
Innovation Solution
The method involves applying alternating injection patterns with differing numbers of pulses to a cylinder, analyzing the resulting engine speed and torque variations using techniques like Fast Fourier Transform to detect injector drift, which manifests as periodic changes in crankshaft angular velocity, allowing for the identification of over-fueling or under-fueling issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If multiple injection pulses are used to distribute fuel delivery, then emissions and noise are reduced, but injector drift effects are scaled and fuel delivery accuracy deteriorates
Solution Approach 1:
The patent applies periodic action by alternating between two different injection patterns (first pattern with multiple pulses, second pattern with different pulse distribution) to periodically excite the system. This allows detection of injector drift through periodic variations in engine speed while maintaining the benefits of multiple injection pulses for emissions reduction.
Solution Approach 2:
The patent changes the parameter of injection pulse distribution by switching between different injection patterns with varying numbers and timing of pulses. This parameter change enables detection of drift while preserving the low-emission benefits of distributed fuel delivery.
2Reliability
If injector drift is detected using traditional OBD methods comparing crankshaft speeds, then some malfunction detection is achieved, but detection precision deteriorates due to injector drift variation between injectors
Solution Approach 1:
By alternating between two injection patterns, the patent creates periodic variations in engine speed that specifically highlight injector drift. This periodic excitation enhances the detectability of drift signals above normal operational variations, improving measurement precision.
Solution Approach 2:
The patent performs preliminary action by intentionally introducing controlled variations in injection patterns before actual drift detection occurs. This preparatory step creates measurable signals that make subsequent drift detection more precise.
3Measurement precision
If alternating injection patterns are applied to detect drift, then detection precision is improved, but device complexity increases due to multiple injection patterns
Solution Approach 1:
The patent segments the fuel injection process into distinct patterns (first pattern with multiple pulses, second pattern with different distribution). This segmentation allows independent optimization of each pattern for detection purposes while keeping the overall system manageable.
Solution Approach 2:
The periodic alternation between two relatively simple injection patterns achieves detection precision without requiring a single overly complex pattern. The simplicity of individual patterns combined with periodic switching keeps device complexity manageable.
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 effectively detects injector drift by introducing a specific frequency component into the engine speed signal, enabling the isolation and correction of fuel injection errors, thereby reducing engine emissions and improving fuel delivery accuracy.
Implementation Method 1
analyzing the resulting engine speed and torque variations using techniques like Fast Fourier Transform to detect injector drift
Data Source
AI summary
Injector drift for a diesel engine are detected by reconfiguration of injection patterns from one pattern into a pattern with a different number of pulse points while attempting to hold total fuel injected constant. If a particular injector is subject to drift then changes in the pulse pattern result in an increase or decrease in fuel injected and consequential variations in engine speed. By applying alternating injection patterns at constant fuel demand and allowing engine speed time to stabilize, a rhythmic variation in engine speed/torque will appear which can be detected using one of a number of techniques.