PFI+DI Fuel Injection Control for Gasoline Particulate Reduction
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Solution Overview
Problem
Spark ignition gasoline engines with direct injection produce higher particulate emissions, which are a health concern and not adequately addressed by current technologies, necessitating a robust and cost-effective solution to reduce these emissions without impacting fuel efficiency.
Innovation Solution
An optimized PFI+DI system that employs advanced control techniques for direct injection timing, spark retard, and fuel injection management to minimize direct injection usage, reduce knock resistance, and control injection timing to minimize particulate generation, potentially eliminating the need for a gasoline particulate filter or enhancing its performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If direct injection is used to improve fuel efficiency and knock resistance, then engine efficiency and power increase, but particulate emissions increase significantly
Solution Approach 1:
The fuel injection system is segmented into two separate injection methods: port fuel injection (PFI) and direct injection (DI). PFI delivers fuel to the port, allowing vaporization and mixing before intake, which reduces particulate formation. DI delivers fuel directly to the cylinder for efficient combustion. By segmenting the injection locations and functions, the system achieves both fuel efficiency improvements and particulate reduction.
Solution Approach 2:
Different injection strategies are applied to different locations within the engine system. PFI provides fuel at the port location for homogeneous mixing and reduced particulates, while DI provides fuel at the cylinder location for efficient combustion and knock resistance. The control system dynamically adjusts the proportion of PFI versus DI based on operating conditions to optimize both efficiency and emissions.
2Power
If direct injection is used to increase turbocharging levels and compression ratio, then engine power increases, but particulate mass and number increase
Solution Approach 1:
The system dynamically adjusts the ratio of PFI to DI based on real-time operating conditions including engine load, speed, and temperature. During high-load conditions where DI provides necessary knock resistance for high compression ratios and turbocharging, the control system increases DI proportion. During low-load conditions, PFI is increased to reduce particulate emissions. This dynamic adjustment allows the engine to maintain high power capability while minimizing particulates during normal operation.
3Object-generated harmful factors
If direct injection timing is optimized to reduce particulates, then particulate emissions decrease, but fuel efficiency may be impacted
Solution Approach 1:
The dual injection system maintains continuous useful action by ensuring that fuel is always being injected through at least one method (PFI or DI) across all operating conditions. PFI provides continuous fuel delivery with vaporization for low particulates, while DI provides continuous direct cylinder injection for efficiency. The control system ensures that the combination of both injection methods continuously delivers the optimal balance of efficiency and emissions control throughout the entire operating range.
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 achieves significant reductions in direct injection-generated particulates (up to 98%) while maintaining or improving fuel efficiency, offering a more reliable and cost-effective solution compared to traditional methods, and can be used alone or in combination with a gasoline particulate filter to further reduce emissions.
Implementation Method 1
The vaporization cooling from direct injection provides increased resistance to knock, thereby allowing operation at higher levels of turbocharging and/or compression ratio.
Implementation Method 2
An optimized PFI+DI system that employs advanced control techniques for direct injection timing, spark retard, and fuel injection management to minimize direct injection usage, reduce knock resistance, and control injection timing to minimize particulate generation
Data Source
AI summary
An optimized port plus direct injection (PFI+DI) fueling system for reducing DI-generated particulates from a spark ignition gasoline engine is disclosed. It uses information from a computational model that includes piston wetting. Means for DI particulate reduction include control of DI timing and duration as a function of various parameters. Illustrative computational results for decreasing particulates in various drive cycles are presented. These calculations illustrate large potential particulate reductions (e.g. 95%) that can be obtained relative to DI operation alone. The optimized PFI+DI system could provide DI generated particulate reduction, efficiency and cost advantages relative to operation of a DI alone engine with a gasoline particulate filter (GPF). Alternatively, it could be used in combination with a GPF to ease GPF operation requirements and provide additional particulate reduction. Techniques for reducing piston wetting generation of particles from use of DI alone are also described.