Numerical Analysis of High-Pressure Direct Injection Dual-Fuel Diesel-Liquefied Natural Gas (LNG) Engines

Boretti, Alberto

doi:10.3390/pr8030261

Cited by 14 publications

(5 citation statements)

References 45 publications

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“…Flexibility is the major advantage of the diesel ICE, that, if needed, dual fuel operation may further increase, 36 without any need of a further breakthrough, only refinements of already existing technologies. In dual fuel operation, the second fuel may have much better than diesel combustion properties, as well as much better than diesel CO 2 content, both tailpipe, and LCA.…”

Section: Discussionmentioning

confidence: 99%

Injection rate shaping in diesel engines key of improved volumetric energy storage

Boretti

2021

Energy Storage

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Thanks to injection rate shaping enabled by high pressure, fast actuating, high atomization injectors, diesel engines can deliver fuel energy conversion efficiencies chemical to mechanical above 52%, with power densities up to 130 kW/L while satisfying peak pressure and gradient of pressure build‐up constraints. Despite further research for improving diesel engines and diesel engine vehicles have practically stopped with diesel gate, there are significant margins of further improvements of what is still the best option for the economy and the environment of onboard energy storage. Mechanical energy can be stored onboard, at about ~18.8 to 19.1 MJ/L and ~5.2 to 5.3 kWh/L, or ~22.2 to 22.6 MJ/kg and ~6.1 to 6.3 kWh/kg. This is much more than Li‐ion batteries at less than 0.100 to 0.265 kWh/kg or 0.250 to 0.670 kWh/L.

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Section: Discussionmentioning

confidence: 99%

Injection rate shaping in diesel engines key of improved volumetric energy storage

Boretti

2021

Energy Storage

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“…Computer-Aided Engineering (CAE) ICE performance simulations are very well known and very well established tools, with many different suppliers as well as users of products providing very close results in between them and with experiments. Modelling of V6 TDI engines is discussed in [65][66][67]. The ICE considered is a 3.7-L TDI V6, of bore 92.5 mm, stroke 90 mm, connecting rod length 180 mm, compression ratio 17.5.…”

Section: Computational Proof Of Concept Of Novel Diesel-lng Ice Designsmentioning

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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“…Natural gas (NG) accounts for 24% of the world's energy consumption. NG, among other fossil fuels, has gained global attention and praise due to its lower impact on the environment compared crude oils [1]. It is predicted that more restrictions on the use of crude oil will prompt rapid natural gas growth.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic, Economic and Environmental Analyses of Ammonia-Based Mixed Refrigerant for Liquefied Natural Gas Pre-Cooling Cycle

Soujoudi

Manteufel

2021

Processes

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Analyzing the entire liquefaction cycle, using a large temperature span with many degrees of freedom, may not always result in a practical solution. The objective of this paper is to investigate the feasibility of using an environmentally friendly refrigerant compound, ammonia, in the mixed refrigerant (MR) for the liquefied natural gas (LNG) pre-cooling cycle through thermodynamic performance, economic analyses and environmental impact. Fifteen cases studies within three major mixed refrigerants groups of MR-1, MR-2 and MR-3 were developed by adding ammonia to various molar compositions of lighter and heavier hydrocarbons. The thermodynamic analysis shows increasing ammonia’s concentrations in the mixed refrigerant by 10% had the largest enhancement on coefficient of performance (COP) of MR-1 by 0.67 and decreased the specific energy consumption of the pre-cooling cycle by 128 kJ/kg compared to the base case. Economic analyses revealed that the mixed refrigerant MR-1, with ammonia, methane, ethane and propane, benefited the most from higher concentration of ammonia in the mixed refrigerant, which resulted in both lower annual capital and operational costs by $2.52 MM and $3.67 MM, respectively. Lastly, reducing the methane concentration in MR and replacing it with ammonia, decreased the amount of refrigerant leakage through compressor’s seals and reduced the global warming potential index (GWPI) of mixed refrigerant up to 24.3%.

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Numerical Analysis of High-Pressure Direct Injection Dual-Fuel Diesel-Liquefied Natural Gas (LNG) Engines

Cited by 14 publications

References 45 publications

Injection rate shaping in diesel engines key of improved volumetric energy storage

Injection rate shaping in diesel engines key of improved volumetric energy storage

Advances in Diesel-LNG Internal Combustion Engines

Thermodynamic, Economic and Environmental Analyses of Ammonia-Based Mixed Refrigerant for Liquefied Natural Gas Pre-Cooling Cycle

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