Effect of the Miller cycle on the performance of turbocharged hydrogen internal combustion engines

Luo, Qing-he; Sun, Baigang

doi:10.1016/j.enconman.2016.06.039

Cited by 46 publications

(8 citation statements)

References 22 publications

(14 reference statements)

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“…Because of the reduced internal compression, the fixed expansion stroke r e becomes larger than the compression one r (overexpansion); being the result of a lower end of expansion pressure p 5 , Figure 1. The now widespread turbocharged Miller cycle has been proposed for using hydrogen as fuel, e.g., Luo and Sun [23], thus exploring its capabilities for a sustainable future. The higher cycle efficiency results in a lower exhaust temperature, limiting extracting power from an exhaust turbine and/or an Organic Rankine cycle (ORC).…”

Section: Gas Exchange Process and The Miller Cyclementioning

confidence: 99%

Open Dual Cycle with Composition Change and Limited Pressure for Prediction of Miller Engines Performance and Its Turbine Temperature

2021

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An improved thermodynamic open Dual cycle is proposed to simulate the working of internal combustion engines. It covers both spark ignition and Diesel types through a sequential heat release. This study proposes a procedure that includes (i) the composition change caused by internal combustion, (ii) the temperature excursions, (iii) the combustion efficiency, (iv) heat and pressure losses, and (v) the intake valve timing, following well-established methodologies. The result leads to simple analytical expressions, valid for portable models, optimization studies, engine transformations, and teaching. The proposed simplified model also provides the working gas properties and the amount of trapped mass in the cylinder resulting from the exhaust and intake processes. This allows us to yield explicit equations for cycle work and efficiency, as well as exhaust temperature for turbocharging. The model covers Atkinson and Miller cycles as particular cases and can include irreversibilities in compression, expansion, intake, and exhaust. Results are consistent with the real influence of the fuel-air ratio, overcoming limitations of standard air cycles without the complex calculation of fuel-air cycles. It includes Exhaust Gas Recirculation, EGR, external irreversibilities, and contemporary high-efficiency and low-polluting technologies. Correlations for heat ratio γ are given, including renewable fuels.

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Section: Gas Exchange Process and The Miller Cyclementioning

confidence: 99%

Open Dual Cycle with Composition Change and Limited Pressure for Prediction of Miller Engines Performance and Its Turbine Temperature

2021

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“…Zhou et al 17 applied the Miller cycle to a two‐stroke marine diesel engine and reported that NOx abated at very high rates with by optimizing the fuel injection angle of the injector. Luo and Sun 18 reported that the Miller cycle decreased specific fuel consumption up to 22% and increased power density up to 37.7% of a spark ignition engine fueled with hydrogen. Yan et al 19 claimed that the thermal efficiency enhanced up to 2% by optimizing spark advance, EGR, and compression ratios simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Performance investigation and evaluation of an engine operating on a modified dual cycle

Gonca

Şahi̇n

2021

Intl J of Energy Research

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Summary In this study, a novel high‐performance engine cycle composed of 5 processes and including constant temperature process has been developed by using novel numerical methods and compared with the classical dual cycle. The results of the classical thermodynamic model demonstrated that the proposed cycle which has a constant temperature process is better in terms of thermal efficiency and dimensionless net work compared to the classical dual cycle. After the validation of superiority of the developed cycle over the classical dual cycle, performance investigations of the novel cycle engine have been carried out in terms of power, power density, destructed exergy, thermal efficiency, ecological coefficient of performance, effective ecological power density by developing a novel fuel‐air cycle model. The influences of design and operational parameters such as cut‐off ratio, compression ratio, cycle temperature ratio, equivalence ratio, engine speed, stroke length, cylinder bore, cylinder wall temperature, air intake temperature, pressure ratio, on the performance specifications have been numerically derived.

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“…They discussed that NO x emissions could be considerably abated by optimizing injection direction of fuel and exhaust valve close timing without penalty of fuel consumption. Luo and Sun asserted that a hydrogen‐fueled MC engine could provide higher power density and lower break‐specific fuel consumption (BSFC) compared with Otto cycle hydrogen engines at 2800 rpm. They reported that the power output of the MC hydrogen engine increased by 37.7% and the BSFC of the MC hydrogen engine decreases by 22% in comparison with the Otto cycle hydrogen engines.…”

Section: Introductionmentioning

confidence: 99%

Performance analysis of a novel eco‐friendly internal combustion engine cycle

Gonca

Şahi̇n

2019

Int J Energy Res

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Summary The Miller cycle applications have been performed to diminish NOx released from internal combustion engines (ICEs), in recent years. The Miller cycle provides decreased compression ratio and enhanced expansion ratio; hereby, maximum in‐cylinder combustion temperatures diminish, and NOx formations slow down remarkably. Another less‐known method is Takemura cycle application, which provides heat addition into engine cylinder at constant combustion temperatures. In this study, a novel cycle including the Miller cycle and the Takemura cycle has been developed by using novel numerical models and computing methods with seven processes and a novel way to decrease NOx emissions at higher levels compared with the single applications of known cycles. A comprehensive performance examination of the proposed cycle engine in terms of performance characteristics such as effective power (EFP), effective power density (EFPD), exergy destruction (X), exergy efficiency (ε), and ecological coefficient of performance (ECOP) has been conducted. The impacts of engine operating and design parameters on the performance characteristics have been computationally examined. Furthermore, irreversibilities depending on incomplete combustion loss (INCL), exhaust output loss (EXOL), heat transfer loss (HTRL), and friction loss (FRL) have been considered in the performance simulations. The minimum exergy destruction and maximum performance specifications have been observed with 30 of the compression ratio. Maximum effective power values have been obtained at range between 1 and 1.2 of equivalence ratio. The optimum range for exergy efficiency is between 0.8 and 1 of equivalence ratio. Increasing engine speed has provided enhancing effective power. However, an optimum range has been found for the exergy efficiency that is interval of 3000 to 4000 rpm. The results obtained can be assessed by researchers studying on modeling of the engine systems and designs.

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Effect of the Miller cycle on the performance of turbocharged hydrogen internal combustion engines

Cited by 46 publications

References 22 publications

Open Dual Cycle with Composition Change and Limited Pressure for Prediction of Miller Engines Performance and Its Turbine Temperature

Open Dual Cycle with Composition Change and Limited Pressure for Prediction of Miller Engines Performance and Its Turbine Temperature

Performance investigation and evaluation of an engine operating on a modified dual cycle

Performance analysis of a novel eco‐friendly internal combustion engine cycle

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