Dual Path Fuel Injection System for Transient Emission Control
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Solution Overview
Problem
Current fuel injection systems face challenges in mitigating particle emissions during transient engine operating conditions, particularly due to fuel impingement on the piston leading to diffusion flames and soot formation when transitioning from low to high load operations.
Innovation Solution
A dual path fuel injection system that includes both port fuel injection (PFI) and direct fuel injection (DI), where an electronic control unit strategically controls the injection based on engine load and piston temperature to reduce impingement by initially engaging PFI for a limited time during load changes and transitioning to DI as the piston heats up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If direct fuel injection is used at high load operating points, then fuel efficiency is improved, but particle emissions increase due to fuel impingement on the piston
Solution Approach 1:
The fuel injection system is segmented into two separate injection paths: port fuel injection (PFI) and direct injection (DI). Each path serves different operating conditions - PFI for low load and transient conditions to avoid impingement, and DI for high load conditions for fuel efficiency. This segmentation allows the system to optimize for either emission control or efficiency depending on the operating point.
Solution Approach 2:
The system dynamically switches between PFI and DI modes based on real-time operating conditions including engine load, piston temperature, and transient state. The control system adjusts the injection path selection and injection timing dynamically to prevent fuel impingement on cold pistons during transients while maintaining DI for efficiency at steady-state high load.
2Power
If fuel injection duration is increased to meet high load demand, then power output is improved, but spray penetration increases causing fuel impingement on the piston
Solution Approach 1:
The intake port and airflow serve as an intermediary medium for fuel delivery during transient high-load conditions. By injecting fuel into the intake port rather than directly into the cylinder, the system uses the airflow to transport fuel to the combustion chamber, avoiding direct impingement on the piston while still meeting the increased power demand.
Solution Approach 2:
The system changes the injection parameters including injection timing, injection duration, and injection pressure based on operating conditions. During transient high-load conditions, the injection timing is advanced and duration is adjusted to allow fuel to mix with intake air before entering the cylinder, reducing spray penetration and impingement risk while maintaining power output.
3Speed
If the engine transitions quickly from low load to high load, then responsiveness is improved, but piston temperature remains low causing diffusion flames and soot formation
Solution Approach 1:
The system performs preliminary fuel injection into the intake port before the fuel enters the combustion chamber during transient conditions. This preliminary action in the intake port allows fuel to begin evaporating and mixing with air before contact with the piston, reducing the risk of diffusion flames and soot formation even during rapid load transitions.
Solution Approach 2:
The system maintains continuous monitoring of piston temperature and adjusts injection strategy accordingly. During transient high-load conditions, the system continuously manages the balance between PFI and DI to ensure fuel is delivered in a manner that accounts for the evolving piston temperature, preventing soot formation while maintaining responsive power delivery.
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 reduces particle emissions by minimizing fuel impingement on the piston during transient conditions, balancing fuel flow between PFI and DI to ensure efficient evaporation and combustion, thereby mitigating the formation and emission of particles.
Implementation Method 1
a port fuel injector disposed in an intake pipe of the cylinder
Implementation Method 2
a direct fuel injector disposed in a cylinder of the engine
Implementation Method 3
a first device that monitors a load of the engine, and outputs a signal corresponding to the load of the engine
Data Source
AI summary
A combination port fuel injection (PFI) and direct injection (DI) dual path fuel injection system includes an electronic control unit (ECU) that switches between the PFI portion and the DI portion depending on the engine operating point and fuel flow requirements. During transitions in engine loading, the ECU instructs the PFI portion to increase injection for a limited amount of time, while instructing the DI portion to maintain a current injection. Subsequently, fueling is transitioned from the PFI portion back to the DI portion. Advantageously, the combination PFI and DI dual path fuel injection system mitigates the emission of particles during transient engine operating conditions.