Fuel Composition for Partially Premixed Combustion
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Solution Overview
Problem
Current fuel compositions for advanced combustion engines, particularly in partially premixed combustion (PPC) mode, fail to achieve optimal synergy between fuel mixture, NOx reduction, soot reduction, and expansion of the operating speed-load range, leading to limited engine performance and high noise levels.
Innovation Solution
A gasoline fuel composition with a boiling range of 95 to 440 degrees Fahrenheit, containing at least 22 volume percent of n-paraffins and naphthenes, and a Research Octane Number (RON) of about 93 or less, is used in an internal combustion engine with a compression ratio of 12:1 to 16:1 and operated under partially premixed combustion conditions, achieving low NOx and soot emissions and high efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If Homogeneous Charge Compression Ignition (HCCI) is used to achieve high efficiency and low emissions, then fuel economy improves and emissions decrease, but combustion control becomes difficult and pressure rise rates become unacceptably high causing noise and potential engine damage
Solution Approach 1:
The patent applies parameter changes by transitioning from HCCI to PPC combustion mode, which fundamentally alters the combustion process parameters. PPC allows controlled fuel injection timing closer to top dead center, creating a partially premixed combustion process that reduces pressure rise rates while maintaining efficiency. The specific fuel composition parameters (octane number 69-90, boiling range distribution) are also optimized to work synergistically with PPC to achieve acceptable pressure rise rates and high efficiency simultaneously
2Object-generated harmful factors
If exhaust after-treatment systems (SCR, lean NOx traps, diesel particulate filters) are added to reduce emissions, then emission levels decrease, but vehicle weight increases and fuel economy deteriorates
Solution Approach 1:
The patent converts the harmful combustion process into a beneficial one by using PPC mode that inherently produces low NOx and low soot emissions at the engine source. This eliminates or reduces the need for heavy after-treatment systems, thereby reducing vehicle weight while maintaining emission compliance. The specific fuel composition (octane number 69-90, n-paraffins and naphthenes content) is optimized to work synergistically with PPC to achieve ultra-low emissions without requiring complex after-treatment systems
3Productivity
If fuel injection timing is advanced to achieve homogeneous mixing for HCCI, then combustion efficiency improves, but combustion control is lost and operating speed-load range is limited
Solution Approach 1:
The patent applies dynamics by making the fuel injection timing flexible and adjustable in PPC mode. Fuel can be injected at variable timings (closer to top dead center) depending on the operating conditions, allowing the engine to adapt to different speed-load ranges while maintaining controlled combustion. This dynamic control capability expands the operating range compared to fixed timing HCCI, while the optimized fuel composition (octane number 69-90) enables stable combustion across this expanded range
4Object-generated harmful factors
If specific fuel compositions are used to optimize PPC performance, then NOx and soot emissions decrease and efficiency increases, but pressure rise rate control becomes challenging
Solution Approach 1:
The patent optimizes multiple fuel composition parameters simultaneously: octane number (69-90), boiling range distribution (95-440°F), and specific component content (n-paraffins and naphthenes ≥22 volume percent). This multi-parameter optimization creates a synergistic effect where the fuel properties work together with PPC combustion to achieve low emissions while controlling pressure rise rates. The balanced composition prevents excessive reactivity that would cause high pressure rise rates while maintaining combustion 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
The fuel composition enables engine efficiencies exceeding 50% and significant reductions in NOx and soot emissions, while maintaining acceptable maximum pressure rise rates, expanding the operating range to up to 18 bar gross IMEP with reduced exhaust gas recirculation rates.
Implementation Method 1
fuel compositions that yield very low soot and low NOx emissions while having high efficiencies and acceptable maximum in-cylinder pressure rise rates over a wide load range when used in an advanced combustion engine environment, especially one operating in partially-premixed combustion (PPC) mode
Data Source
AI summary
A fuel composition having a boiling range of between 95 to 440 degrees Fahrenheit wherein the fuel composition has (a) a total sum of n-paraffins and naphthenes content of at least 22 volume percent and (b) a RON of about 93 or less, wherein the fuel is employed in an advanced combustion engine.