Efficiency and Emissions Characteristics of Partially Premixed Dual-Fuel Combustion by Co-Direct Injection of NG and Diesel Fuel (DI<sup>2</sup>) - Part 2

Neely, Gary D.; Florea, Radu; Miwa, Jason; Abidin, Zainal

doi:10.4271/2017-01-0766

Cited by 20 publications

(28 citation statements)

References 19 publications

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“…In addition to assisted turbocharging, air cooling, and injection shaping, exhaust gas recirculation (EGR) is a control option that is effective to reduce the NOx engine-out emissions [52,69,70]. The EGR reduces the NOx lowering the oxygen concentration in the combustion chamber, as well as absorbing heat.…”

Section: Substitutional Lngmentioning

confidence: 99%

Advances in Diesel-LNG Internal Combustion Engines

Boretti

2020

Applied Sciences

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Diesel-LNG internal combustion engines (ICEs) are the most promising light and heavy-duty truck (HDT) powering solution for a transition towards a mixed electric-hydrogen renewable energy economy. The diesel-liquid CH 4 ICEs have indeed many commonalities with diesel-liquid H 2 ICEs, in the infrastructure, on-board fuel storage, and injection technology, despite the fact H 2 needs a much lower temperature. The paper outlines the advantages of dual fuel (2F) diesel-LNG ICEs developed adopting two high-pressure (HP) injectors per cylinder, one for the diesel and one for the LNG, plus super-turbocharging. The diesel-LNG ICEs provide high fuel energy conversion efficiencies, and reduced CO 2 , PM, and NOx emissions. Super-turbocharging permits the shaping of the torque curve while improving acceleration transients. Diesel-LNG ICEs may also clean up the air of background pollution in many polluted areas in the world. Computational results prove the steady-state advantages of the proposed novel design. While the baseline diesel model is a validated model, the 2F LNG model is not. The perfect alignment of the diesel and diesel-LNG ICE performances proven by Westport makes however the proposed results trustworthy. the lean-burn operation, with combustion occurring with excess air [23]. The reduction of both PM and NOx is achieved by after-treatment. As the after-treatment is imperfect, the diesel combustion strategies are dictated by the best trade-off between PM and NOx emissions.The use of a fuel with reduced carbon content, that is also gas in normal conditions, such as the NG, has major advantages in both CO 2 and engine-out PM emissions. Even if injected liquid, the NG rapidly vaporizes and quickly mixes with the air. The PM emissions are usually negligible. Not having the constraint of the best PM-NOx trade-off to design the injection profile, the injection profile can be shaped to achieve reduced NOx production. Thus, NG indirectly also permits to reduce the NOx engine-out emissions. NG (CH 4 ) has a smaller carbon-to-hydrogen ratio vs. the diesel (C 13.5 H 23.6 ) also featuring a higher lower heating value. Less CO 2 is emitted to produce the same output of the diesel with the same η. As NG is also gas in normal conditions, this practically reduces to zero the PM emissions. In the dual-fuel (2F) operation, the only PM originates from the pilot diesel.As NG is a low cetane but a high octane number fuel, it is difficult to use alone in a CI ICE The issue is solved by using the 2F diesel-NG design with the diesel-injection-ignition [24,25]. A small amount of the DI diesel fuel ignites mixed with air within the cylinder. The NG that is injected prior, or after the diesel, then burns premixed, i.e. diffusion. The first phase of combustion translates into a rapid pressure build-up. The rate of combustion of the second phase is determined by the injection rate of the NG.One issue with fuels that are gases under normal conditions is the specific volume, as the density of the gas under normal conditions is much lower than...

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Section: Substitutional Lngmentioning

confidence: 99%

Advances in Diesel-LNG Internal Combustion Engines

Boretti

2020

Applied Sciences

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“…The DI 2 combustion mode is also studied in Neely et al (2017). The natural gas is injected during the compression stroke prior to the diesel injection ignition.…”

Section: Future Technologymentioning

confidence: 99%

Advantages and Disadvantages of Diesel Single and Dual-Fuel Engines

Boretti

2019

Front. Mech. Eng.

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The pros and the cons of lean-burn, compression ignition (CI), direct injection (DI) internal combustion engines (ICE) are reviewed for transport applications. Fueling options considered include diesel only and dual-fuel applications with diesel and a gaseous fuel (CNG, LNG, and LPG). CIDI ICEs have higher fuel conversion efficiencies than stoichiometric, spark ignition (SI) ICEs, whether DI or port fuel injected (PFI). However, diesel-fueled CIDI ICEs have higher particulate matter (PM) and NOx engine-out emissions. The tail-pipe NOx emissions in real-world driving of diesel-powered vehicles have been, in the past, above the limits requested over the simplified cold start driving cycles used for certification. This issue has recently been resolved. The newest diesel-powered vehicles are now compliant with new laboratory test cycles and real-world-driving schedules and have no disadvantages in terms of criteria air pollutants compared to older diesel vehicles, while delivering improvements in fuel economy and CO 2 emissions. Dual-fuel CIDI ICEs offer the opportunity for enhanced environmental friendliness. Dual-fuel CIDI ICEs have lower engine-out NOx and PM emissions compared to diesel-only CIDI ICEs. The latest diesel-only vehicles and vehicles with dual-fuel ICEs deliver dramatic reductions in tail-pipe PM emissions compared to older diesel-only vehicles. Moreover, they deliver tail-pipe PM emissions well below the ambient conditions in most city areas that are highly polluted, thereby helping to clean the air. The diesel-fueled CIDI ICEs may be further improved to deliver better fuel economy and further reduced tail-pipe emissions. The dual-fuel CIDI ICE has more room for improvement to produce similar or better steady state and transient performance in terms of torque, power output and fuel conversion efficiency compared to diesel-fueled CIDI ICEs, while drastically reducing CO 2 and PM tail-pipe emissions, and improving NOx tail-pipe emissions. This is due to the ability to modulate the premixed and diffusion phases of combustion with a second fuel that is much easier to vaporize and is less prone to auto-ignition. Further development of the fuel injection system for the second fuel will lead to novel dual-fuel CIDI ICE designs with better performance.

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“…The benefits included an increase from 46.8 to 47.5% efficiency when modifying the nozzle angle at 1000RPM 12 bar BMEP [4]. Another benefit of the study showed DI 2 showed up to 50% decrease in combustion losses compared to a fumigated fully pre-mixed NG dual fuel engine [4].…”

Section: Natural Gas Combustion Systemsmentioning

confidence: 99%

“…Neely et al studied the benefits of partially pre-mixed natural gas spray angle being ignited by a pilot of diesel fuel would ignite a previously direct-injected natural gas using a 3D-CFD model [4]. The benefits included an increase from 46.8 to 47.5% efficiency when modifying the nozzle angle at 1000RPM 12 bar BMEP [4]. Another benefit of the study showed DI 2 showed up to 50% decrease in combustion losses compared to a fumigated fully pre-mixed NG dual fuel engine [4].…”

Section: Natural Gas Combustion Systemsmentioning

confidence: 99%

“…4 shows side 1 of the interface panel which contains the connections for the coolant supply and return, as well as the quick connects used for the diesel and CNG fuel. The engine coolant system uses the conventional test-cell cam-lock quick disconnects to allow engine coolant in (cold) and out (hot) to flow from the engine.The diesel system has connections for high pressure controlled by the diesel standalone cart as well as return plumbing.…”

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Design, Build, and Analysis of a Compressed Natural Gas Direct Injection Compression Ignition Single Cylinder Research Engine

Miller¹

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Efficiency and Emissions Characteristics of Partially Premixed Dual-Fuel Combustion by Co-Direct Injection of NG and Diesel Fuel (DI²) - Part 2

Cited by 20 publications

References 19 publications

Advances in Diesel-LNG Internal Combustion Engines

Advances in Diesel-LNG Internal Combustion Engines

Advantages and Disadvantages of Diesel Single and Dual-Fuel Engines

Design, Build, and Analysis of a Compressed Natural Gas Direct Injection Compression Ignition Single Cylinder Research Engine

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Efficiency and Emissions Characteristics of Partially Premixed Dual-Fuel Combustion by Co-Direct Injection of NG and Diesel Fuel (DI2) - Part 2

Cited by 20 publications

References 19 publications

Advances in Diesel-LNG Internal Combustion Engines

Advances in Diesel-LNG Internal Combustion Engines

Advantages and Disadvantages of Diesel Single and Dual-Fuel Engines

Design, Build, and Analysis of a Compressed Natural Gas Direct Injection Compression Ignition Single Cylinder Research Engine

Contact Info

Product

Resources

About

Efficiency and Emissions Characteristics of Partially Premixed Dual-Fuel Combustion by Co-Direct Injection of NG and Diesel Fuel (DI²) - Part 2