Investigation of Reactivity Controlled Compression Ignition Compared to Binary Mixtures to Reduce Soot and NOX Emissions while Maintaining Efficiency in an Omnivorous Engine

Primary Faculty Mentor’s Name

Dr. Valentin Soloiu

Proposal Track

Student

Session Format

Poster

Abstract

In this study, Reactivity Controlled Compression Ignition (RCCI) was investigated with a renewable biofuel to determine its influence on emissions and engine performance. RCCI leads to low temperature combustion (LTC) which has been achieved with a dual fueling strategy which includes an early port fuel injection (PFI) of a low reactive fuel, renewable n-butanol, and a direct injection of a highly reactive fuel, ultra-low sulfur diesel#2 (ULSD#2). Through RCCI, soot and NO emissions can be reduced without affecting engine performance. Premixed binary mixtures of n-butanol and ULSD#2 were tested also along with fuel atomization and mixture formation. 35%, 50%, and 65% n-butanol/ULSD#2 blends were investigated and compared to 35%, 50%, and 65% PFI of n-butanol. The MIE scattering spray characterization determined the correlation between particle size distributions of ULSD/n-butanol mixtures with their respective mixture ratios. Higher concentrations of n-butanol in binary mixtures of ULSD and n-butanol led to the formation of droplets with lower Sauter Mean Diameters and vice versa. Smaller droplets are preferred because they provide significantly more surface area for combustion to take place resulting in a more efficient reaction. The two different fueling strategies yielded opposite trends in the ringing intensity analysis and the apparent heat release analysis. As the concentration of n-butanol in the diesel blends increased, the ringing intensity increased, and vice versa for the port fuel injection strategy. The ringing intensity analysis provided remarkable results for the project. The ringing intensity has never been calculated for the blends and fueling strategies tested. A similar trend was observed for the apparent heat release rates. The emissions results were favorable with up to 90% decrease in soot emissions for the blends and up to 78% with RCCI. NOX also decreased by 10% for both fueling strategies. The mechanical efficiency remained relatively constant between 74-77% for both fueling strategies. The indicated thermal efficiency showed a decreasing trend for both fueling strategies as the concentration of n-butanol increased. However, the changes in indicated thermal efficiency were minimal. The results of this study indicate that using binary mixtures of n-butanol and ULSD#2 is most effective at reducing emissions and maintaining engine efficiency.

Keywords

RCCI, LTC, Diesel, Engines, Biofuel, Combustion, Emissions, n-butanol

Location

Concourse/Atrium

Presentation Year

2014

Start Date

11-15-2014 2:55 PM

End Date

11-15-2014 4:10 PM

Publication Type and Release Option

Presentation (Open Access)

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Nov 15th, 2:55 PM Nov 15th, 4:10 PM

Investigation of Reactivity Controlled Compression Ignition Compared to Binary Mixtures to Reduce Soot and NOX Emissions while Maintaining Efficiency in an Omnivorous Engine

Concourse/Atrium

In this study, Reactivity Controlled Compression Ignition (RCCI) was investigated with a renewable biofuel to determine its influence on emissions and engine performance. RCCI leads to low temperature combustion (LTC) which has been achieved with a dual fueling strategy which includes an early port fuel injection (PFI) of a low reactive fuel, renewable n-butanol, and a direct injection of a highly reactive fuel, ultra-low sulfur diesel#2 (ULSD#2). Through RCCI, soot and NO emissions can be reduced without affecting engine performance. Premixed binary mixtures of n-butanol and ULSD#2 were tested also along with fuel atomization and mixture formation. 35%, 50%, and 65% n-butanol/ULSD#2 blends were investigated and compared to 35%, 50%, and 65% PFI of n-butanol. The MIE scattering spray characterization determined the correlation between particle size distributions of ULSD/n-butanol mixtures with their respective mixture ratios. Higher concentrations of n-butanol in binary mixtures of ULSD and n-butanol led to the formation of droplets with lower Sauter Mean Diameters and vice versa. Smaller droplets are preferred because they provide significantly more surface area for combustion to take place resulting in a more efficient reaction. The two different fueling strategies yielded opposite trends in the ringing intensity analysis and the apparent heat release analysis. As the concentration of n-butanol in the diesel blends increased, the ringing intensity increased, and vice versa for the port fuel injection strategy. The ringing intensity analysis provided remarkable results for the project. The ringing intensity has never been calculated for the blends and fueling strategies tested. A similar trend was observed for the apparent heat release rates. The emissions results were favorable with up to 90% decrease in soot emissions for the blends and up to 78% with RCCI. NOX also decreased by 10% for both fueling strategies. The mechanical efficiency remained relatively constant between 74-77% for both fueling strategies. The indicated thermal efficiency showed a decreasing trend for both fueling strategies as the concentration of n-butanol increased. However, the changes in indicated thermal efficiency were minimal. The results of this study indicate that using binary mixtures of n-butanol and ULSD#2 is most effective at reducing emissions and maintaining engine efficiency.