PFDI Engine Fueling Error Learning via Dynamic Fraction Adjustment
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Solution Overview
Problem
Existing methods for identifying fueling errors in Port Fuel Direct Injection (PFDI) engines struggle to accurately differentiate errors between port and direct fuel injection systems, especially at lower injection fuel masses and smaller changes in fuel fraction, leading to reduced confidence in error estimation and potential emissions issues due to infrequent fuel canister purging.
Innovation Solution
The approach involves opportunistically learning initial fuel fractions via a non-intrusive calibration routine and then intrusively adjusting fuel fractions within dynamically selected upper and lower limits based on engine speed-load conditions to enable reliable detection and differentiation of air-fuel ratio errors, thereby improving fuel system calibration confidence and increasing fuel canister purging frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If non-intrusive calibration routine is used to identify fueling errors, then vehicle drivability is maintained, but fuel error detection accuracy is reduced at lower injection fuel masses
Solution Approach 1:
The system dynamically switches between non-intrusive calibration mode (maintaining normal fuel injection for drivability) and intrusive calibration mode (injecting additional fuel for accurate error detection). The calibration routine adapts its intrusiveness based on detected fuel mass levels, using intrusive adjustments only when necessary to achieve reliable error differentiation.
Solution Approach 2:
The system applies partial intrusive action by injecting additional fuel above the normal fuel mass only during calibration events. This excessive fuel injection is used selectively to create sufficient signal for accurate error detection, while the system returns to normal operation afterward, balancing measurement accuracy with operational normality.
2Measurement precision
If intrusive fuel fraction adjustment is made to provide sufficient test conditions for calibration, then fuel error detection accuracy is improved, but vehicle drivability is affected
Solution Approach 1:
The system performs intrusive calibration adjustments periodically rather than continuously. Normal fuel injection is maintained during regular operation, with intrusive calibration events occurring at scheduled intervals or under specific conditions, allowing accurate error detection without持续 impacting drivability.
Solution Approach 2:
The system performs preliminary intrusive fuel adjustments during calibration routines before normal operation resumes. By completing the intrusive calibration action in advance and returning to normal fuel injection, the system ensures accurate error detection is achieved without prolonged impact on vehicle drivability.
3Stability of the object's composition
If fuel canister purging is delayed until calibration is completed, then air-fuel ratio excursions are reduced, but emissions are degraded due to canister saturation
Solution Approach 1:
The system performs preliminary fuel canister purging during or before calibration routines. By proactively purging the canister of accumulated fuel vapors, the system prevents canister saturation and associated emissions problems, while maintaining air-fuel ratio stability through coordinated control of the purging process.
Solution Approach 2:
The system maintains continuous useful action by coordinating fuel canister purging with calibration routines. Rather than delaying purging until calibration completes, the system integrates purging actions to continue removing fuel vapors throughout the calibration process, preventing saturation while maintaining measurement accuracy.
Data Source
AI summary
Methods and systems are provided for enabling a transfer function of a direct injector and a port injector, each fueling an engine cylinder, to be accurately learned. During selected conditions, the direct injected fuel fraction may be actively changed from a target fraction to one of an upper and lower limit of the direct injector so as to provide a measurable air-fuel ratio error. Fueling errors for the distinct fuel injectors is then learned based on the measured air-fuel ratio error relative to the actively changed fuel fraction.