Direct Fuel Injector Control with Variable Current Profiles
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Solution Overview
Problem
Existing direct fuel injection systems for internal combustion engines face limitations in providing different injector current profiles for consecutive fuel pulses due to bandwidth constraints, making precise control of fuel delivery for stringent emission and fuel economy goals challenging.
Innovation Solution
A dual-controller system where a microprocessor determines injector selection, timing, and duration, and a state machine controls current profiles, allowing quick switching between preloaded sets of injector current profile parameters stored in register sets, enabling different current profiles for successive injection pulses during a single combustion event.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single microprocessor controls injector current profiles directly, then system complexity is reduced, but communication bandwidth limitations prevent reliable provision of different current profiles for consecutive fuel pulses
Solution Approach 1:
The control system is divided into two separate controllers: a microprocessor that manages fuel injection timing and duration, and a dedicated state machine controller that handles injector current profile generation. This segmentation allows the state machine to reliably control current profiles for consecutive fuel pulses without being constrained by microprocessor communication bandwidth limitations, while the microprocessor focuses on higher-level injection management.
2Manufacturing precision
If different injector current profiles are provided for each injector, then manufacturing variations are compensated, but the system cannot provide different current profiles for consecutive fuel pulses in multi-pulse delivery
Solution Approach 1:
The state machine controller is designed to dynamically switch between different injector current profile parameter sets for consecutive fuel pulses within a single combustion event. This dynamic capability allows the system to provide precise compensation for manufacturing variations while simultaneously enabling adaptive variation of current profiles for multi-pulse delivery strategies, resolving the contradiction between fixed compensation and flexible adaptation.
3Measurement precision
If microprocessor determines all injector control parameters including current profiles, then control precision is improved, but throughput constraints prevent reliable multi-pulse delivery with different current profiles
Solution Approach 1:
The state machine controller extracts and handles the specific function of generating injector current profiles separately from the microprocessor. This extraction allows the microprocessor to maintain precise control over fuel injection timing and duration without being burdened by the high-speed communication requirements of dynamically switching current profiles for consecutive pulses, thereby maintaining control precision while overcoming bandwidth limitations.
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
Enables precise control of fuel delivery by allowing different injector current profiles for each pulse, improving emission control and fuel economy by overcoming bandwidth limitations in existing systems.
Implementation Method 1
solenoid activated fuel injectors
Implementation Method 2
the inductive nature of the injector solenoid coil
Data Source
AI summary
A direct fuel injection control for an internal combustion engine includes first and second controllers. The first controller has a microprocessor and generates injection timing and duration signals on injector select lines. The second controller is a state machine including injector controls that receive the injection timing and duration signals and control injector current according to sets of injector current profile defining parameters received from the first controller on a serial bus and stored in register sets in the second controller. The second controller includes switching apparatus that can quickly change the connection of each injector control between different register sets to select different injector current profiles in successive injection pulses. Several alternative ways of providing register select signals are disclosed, and these may be incorporated in the same second controller for selection by the first controller.