Fuel Injection Control Using Map-Based Correction Blending
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Solution Overview
Problem
Existing fuel injection control strategies in internal combustion engines, such as 'Cylinder Balancing', face challenges in achieving fast convergence during engine operating point transients and maintaining balance under noisy driveline or road conditions, especially when injectors drift in one direction.
Innovation Solution
A method that estimates and stores injector fuel quantity deviations in a map defined by engine operating points, allowing for blending of estimated and stored corrections to balance fuel injection quantities across cylinders, using a combination of closed-loop and open-loop controls, with adjustments for production tolerances and injector drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Cylinder Balancing strategy uses pure integral control to calculate fuel corrections, then torque equalization is achieved, but convergence time during operating point transients is too slow
Solution Approach 1:
The patent stores fuel corrections in a map during steady-state operation before transients occur. During operating point transients, these pre-calculated corrections are immediately applied, eliminating the need to wait for slow integral control convergence. This preliminary action resolves the contradiction by providing fast response during transients while maintaining torque equalization reliability.
Solution Approach 2:
The patent dynamically switches between using stored map corrections during transients and integral control during steady-state operation. This dynamic adaptation allows the system to optimize performance for different operating conditions, achieving fast convergence during transients while maintaining reliable torque equalization during steady operation.
2Reliability
If Cylinder Balancing uses feedback from crank wheel signal, then injector balance is improved, but performance degrades under noisy driveline or road conditions
Solution Approach 1:
The patent introduces a map as an intermediary between the crank wheel feedback and the fuel correction application. The map stores smoothed, representative corrections from steady-state operation, filtering out noise from transient conditions. This intermediary allows the system to benefit from feedback-based balancing while protecting against noise-induced errors during transient operation.
Solution Approach 2:
The patent pre-calculates and stores fuel corrections during clean, steady-state operating conditions before noisy transients occur. These pre-stored corrections are then applied during transient operation, avoiding the use of noisy feedback signals altogether during problematic conditions while maintaining injector balance.
3Reliability
If Cylinder Balancing performs run-time balancing between injectors, then torque equalization is maintained, but average drift of all injectors is not corrected
Solution Approach 1:
The patent segments the fuel correction into two independent components: relative corrections stored in the map that equalize torque between cylinders, and an absolute correction term that compensates for average drift of all injectors. This segmentation allows both functions to be performed simultaneously without interference, resolving the contradiction between maintaining torque equalization and correcting average drift.
Solution Approach 2:
The patent makes the fuel correction system multi-functional by enabling it to simultaneously perform relative balancing (torque equalization) and absolute correction (average drift compensation). The correction map stores relative corrections while a separate mechanism tracks and corrects average drift, allowing the single correction system to fulfill both purposes.
Data Source
AI summary
A method and apparatus for controlling fuel injection in an internal combustion engine is disclosed which controls a fuel injection pressure and a fuel injection energizing time, by using as input parameter an estimated corrected injector fuel quantity (Qcrtd). In particular, an injector fuel quantity deviation (ΔQCB) corresponding to a current engine operating point is estimated and stored in a corresponding point of a map, representing engine operating points defined in terms of injection pressure and injector fuel quantity values. The stored injector fuel quantity deviation (ΔQstored) are spread or propagated to each map point. For each engine operating point, the corrected injector fuel quantity (Qcrtd) is calculated by blending estimated values of the injector fuel quantity deviation (ΔQCB) with corresponding spread values of the stored injector fuel quantity deviation (ΔQstored) and summing this result to corresponding target values of the injector fuel quantity (Qtarget).