Direct Fuel Injector Transition Region Variability Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solenoid-controlled direct fuel injectors exhibit unpredictable flow characteristics in the transition region between the ballistic and full lift regions, leading to variability in fuel injection, which causes torque imbalances, increased emissions, and reduced fuel economy due to non-linear behavior that is difficult to compensate for.
Innovation Solution
An engine controller adjusts the fuel injection profile by estimating an initial ratio of port injected fuel to direct injected fuel based on engine operating conditions and updates it to move the direct fuel injection out of the transition region by modifying the fuel mass and number of injections, ensuring the total fuel mass is maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the direct fuel injector operates in the transition region between ballistic and full lift regions, then the injector can deliver fuel across a wide range of pulse widths, but the flow rate becomes inaccurate and unpredictable causing shot-to-shot and part-to-part variability
Solution Approach 1:
The patent segments the fuel injection system into two separate injection paths: direct injection and port injection. By dividing the total fuel delivery into these two segments, the system can operate the direct injector in its accurate ballistic region for precise fuel metering, while using port injection to compensate for the transition region variability, thus maintaining overall fuel delivery accuracy across a wide pulse width range.
Solution Approach 2:
The patent changes the operational parameters of the direct fuel injector by limiting its pulse width operation to the ballistic region only, avoiding the transition region. This parameter change ensures that the direct injector operates in its most accurate and predictable flow regime, while the overall fuel delivery requirement is met by coordinating with port injection.
2Adaptability or versatility
If the direct fuel injector operates in the transition region, then full control over pulse width range is achieved, but this causes cylinder torque output imbalance and increased emissions
Solution Approach 1:
The patent implements a control strategy that uses feedback from the injector's operating region detection. When the direct injector pulse width would place it in the transition region, the system detects this condition and adjusts the injection strategy accordingly, switching to a combination of direct and port injection modes. This feedback mechanism prevents operation in the harmful transition region while maintaining adaptability across various engine conditions.
Solution Approach 2:
The patent dynamically adjusts the fuel injection strategy based on real-time operating conditions. The system transitions between different injection modes (direct only, port only, or combined) depending on the required pulse width and the current engine state. This dynamic adaptation allows the system to avoid the transition region when necessary while maintaining flexibility to meet varying engine demands.
3Adaptability or versatility
If the direct fuel injector operates in the transition region, then a wide pulse width range is available, but this results in reduced fuel economy
Solution Approach 1:
The patent segments the fuel injection function between direct injection and port injection systems. By dividing the total fuel delivery task, the system can utilize the more fuel-efficient direct injection in its optimal ballistic region for precise metering, while using port injection as a supplemental path that does not compromise overall fuel economy. This segmentation allows the system to maintain fuel injection flexibility without sacrificing fuel efficiency.
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 direct injector variability, improves engine air-fuel ratio and torque accuracy, decreases emissions, and enhances drivability by operating the injector outside the transition region where non-linear behavior occurs.
Implementation Method 1
Solenoid-controlled direct fuel injectors may have a limitation in their flow characteristics
Implementation Method 2
direct fuel injection, wherein fuel is directly injected in to an engine cylinder to improve mixture preparation
Data Source
AI summary
Methods and systems are provided for reducing direct injector fueling errors due to injection variability in a transition region of a direct injector map. Fuel injection, including usage of one or more direct and port injected fuel pulses, may be planned based on engine operating conditions including engine temperature and driver demand. Responsive to any of the direct injected fuel pulses having a pulse-width that lies in a high variability transition region of the direct injector, the fuel injection may be adjusted via adjustments to a number and/or split ratio of the injections so as to not operate in the transition region.