Reactivity Controlled Compression Ignition Investigations with Direct Injection of Synthetic Kerosene and Port Fuel Injection of n-Butanol

Location

Room 2903

Session Format

Paper Presentation

Research Area Topic:

Engineering and Material Sciences - Mechanical

Co-Presenters and Faculty Mentors or Advisors

Tyler Naes

Dr. Valentin Soloiu

Abstract

In this study, the combustion and emissions characteristics of Reactivity Controlled Compression Ignition (RCCI) obtained by direct injection (DI) of synthetic kerosene (SK) and port fuel injection (PFI) of n-butanol were compared with DI of ultra-low sulfur diesel #2 (ULSD#2) and PFI of n-butanol at 1500 rpm and 6 bar indicated mean effective pressure (IMEP). Baselines of DI conventional diesel combustion, with 100% ULSD#2 and DI of SK were conducted. The SK is a synthetic paraffinic kerosene developed by Syntroleum and is derived from natural gas. SK is a Fischer-Tropsch fuel that contains a low aromatic percentage (0.5 vol. %) and has a cetane number of 63. Reactivity Controlled Compression Ignition has shown the possibility to achieve low temperature combustion (LTC) and reduce both NOX and particulate matter (PM) emissions. In this research, RCCI is achieved with a dual fuel injection strategy with PFI of a low reactant fuel, n-butanol, and DI of a high reactant fuel, SK. The present research has never been attempted before with the fuels tested. For both RCCI cases, the mass ratio of DI to PFI was 1:1. The ignition delay for the ULSD#2 baseline was 12.4 CAD (1.38 ms) and for SK was 12.1 CAD (1.34 ms). However, for the RCCI strategies, the ignition delay advanced to 11.2 CAD (1.25 ms) and 11.3 CAD (1.26 ms) for RCCI-ULSD#2 and RCCI-SK, respectively. The SK showed an earlier combustion, yet, combusted more slowly. The combustion duration for SK was 81.5 CAD while the ULSD#2 baseline was 70.2 CAD The premixed charge combustion has been split into two regions of high temperature heat release, an early one BTDC, and a second stage, ATDC for the PFI strategy. Ringing intensities for the different fuels and fueling strategies were calculated. The baseline of ULSD#2 produced the highest ringing intensity of 3.5 MW/m2. SK exhibited a lower ringing intensity of 2.1 MW/m2. For the RCCI strategies, the ringing intensity decreased to 2.4 MW/m2 and 1.1 MW/m2 for both DI-ULSD#2/PFI-n-butanol and DI-SK/PFI-n-butanol, respectively. SK produced 30% less NOX emissions when compared to the ULSD#2 baseline. A simultaneous reduction of NOx and soot was observed with RCCI of DI-SK/PFI-n-butanol where soot and NOX decreased by 66% and 19%, respectively, when compared to the ULSD#2 baseline. However, SK along showed an increase in soot emissions by 250% . Further reduction can be observed with the implementation of an EGR system. The use of DI-SK/PFI n-butanol was compatible in this engine. The coefficient of variability (COV) remained under 3% for over 500 averaged engine cycles. The indicated thermal efficiency was highest for the ULSD#2 baseline at 44%. SK showed the second highest indicated thermal efficiency with 43%. The combustion efficiency for each fuel and fuelling strategy was over 99%. The results indicate that SK is compatible in diesel engines. When coupled with PFI of n-butanol, RCCI is achieved and harmful emissions are reduced without diminishing engine performance.

Keywords

Synthetic kerosene, RCCI, PFI, n-butanol

Presentation Type and Release Option

Presentation (Open Access)

Start Date

4-24-2015 9:30 AM

End Date

4-24-2015 10:30 AM

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Apr 24th, 9:30 AM Apr 24th, 10:30 AM

Reactivity Controlled Compression Ignition Investigations with Direct Injection of Synthetic Kerosene and Port Fuel Injection of n-Butanol

Room 2903

In this study, the combustion and emissions characteristics of Reactivity Controlled Compression Ignition (RCCI) obtained by direct injection (DI) of synthetic kerosene (SK) and port fuel injection (PFI) of n-butanol were compared with DI of ultra-low sulfur diesel #2 (ULSD#2) and PFI of n-butanol at 1500 rpm and 6 bar indicated mean effective pressure (IMEP). Baselines of DI conventional diesel combustion, with 100% ULSD#2 and DI of SK were conducted. The SK is a synthetic paraffinic kerosene developed by Syntroleum and is derived from natural gas. SK is a Fischer-Tropsch fuel that contains a low aromatic percentage (0.5 vol. %) and has a cetane number of 63. Reactivity Controlled Compression Ignition has shown the possibility to achieve low temperature combustion (LTC) and reduce both NOX and particulate matter (PM) emissions. In this research, RCCI is achieved with a dual fuel injection strategy with PFI of a low reactant fuel, n-butanol, and DI of a high reactant fuel, SK. The present research has never been attempted before with the fuels tested. For both RCCI cases, the mass ratio of DI to PFI was 1:1. The ignition delay for the ULSD#2 baseline was 12.4 CAD (1.38 ms) and for SK was 12.1 CAD (1.34 ms). However, for the RCCI strategies, the ignition delay advanced to 11.2 CAD (1.25 ms) and 11.3 CAD (1.26 ms) for RCCI-ULSD#2 and RCCI-SK, respectively. The SK showed an earlier combustion, yet, combusted more slowly. The combustion duration for SK was 81.5 CAD while the ULSD#2 baseline was 70.2 CAD The premixed charge combustion has been split into two regions of high temperature heat release, an early one BTDC, and a second stage, ATDC for the PFI strategy. Ringing intensities for the different fuels and fueling strategies were calculated. The baseline of ULSD#2 produced the highest ringing intensity of 3.5 MW/m2. SK exhibited a lower ringing intensity of 2.1 MW/m2. For the RCCI strategies, the ringing intensity decreased to 2.4 MW/m2 and 1.1 MW/m2 for both DI-ULSD#2/PFI-n-butanol and DI-SK/PFI-n-butanol, respectively. SK produced 30% less NOX emissions when compared to the ULSD#2 baseline. A simultaneous reduction of NOx and soot was observed with RCCI of DI-SK/PFI-n-butanol where soot and NOX decreased by 66% and 19%, respectively, when compared to the ULSD#2 baseline. However, SK along showed an increase in soot emissions by 250% . Further reduction can be observed with the implementation of an EGR system. The use of DI-SK/PFI n-butanol was compatible in this engine. The coefficient of variability (COV) remained under 3% for over 500 averaged engine cycles. The indicated thermal efficiency was highest for the ULSD#2 baseline at 44%. SK showed the second highest indicated thermal efficiency with 43%. The combustion efficiency for each fuel and fuelling strategy was over 99%. The results indicate that SK is compatible in diesel engines. When coupled with PFI of n-butanol, RCCI is achieved and harmful emissions are reduced without diminishing engine performance.