Analyzing Factors Affecting Gross Indicated Efficiency When Inlet Temperature Is Changed

Lam, Nhut; Tunestål, Per; Andersson, Arne

doi:10.4271/2018-01-1780

Cited by 12 publications

(6 citation statements)

References 6 publications

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“…However, not enough information was available in the existing literature regarding these constants, particularly for the compression and expansion cylinders. To simplify this issue, a linear friction model was implemented, similar to previous studies [22,23,37], given by equation 2 as:…”

Section: One-dimensional Simulationsmentioning

confidence: 99%

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A Simulation Study to Understand the Efficiency Analysis of Multiple Injectors for the Double Compression Expansion Engine (DCEE) Concept

Goyal

Nyrenstedt

Cabezas

et al. 2021

SAE Technical Paper Series

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Heavy-duty vehicles face increasing demands of emission regulations. Reduced carbon-dioxide (CO2) emission targets motivate decreased fuel consumption for fossil fuel engines. Increased engine efficiency contributes to lower fuel consumption and can be achieved by lower heat transfer, friction and exhaust losses. The double compression expansion engine (DCEE) concept achieves higher efficiency, as it utilizes a split-cycle approach to increase the in-cylinder pressure and recover the normally wasted exhaust energy. However, the DCEE concept suffers heat losses from the high-pressure approach. This study utilizes up to three injectors to reduce the wall-gas temperature gradient rendering lower convective heat losses. The injector configuration consists of a standard central injector and two side-injectors placed at the rim of the bowl. An increased distance from side-injector to the wall delivered lower heat losses by centralizing hot gasses in the combustion chamber. Computational fluid dynamics (CFD) simulations investigated two different piston bowls, in a heavy-duty diesel engine, to obtain in-cylinder conditions for one, two -and three-injector concepts. One-dimensional (1D) simulations then used the CFD data to obtain the complete efficiency analysis of the DCEE concept. The results showed that the three-injector case improved the brake thermal efficiency and reduced the heat transfer losses, compared to the two-injector and single-injector cases. In particular, the three-injector case resulted in a high indicated and brake thermal efficiency of 58.5 % and 54.2 %, respectively.

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Section: One-dimensional Simulationsmentioning

confidence: 99%

“…where, A and B were fixed at 1.2 and 200, respectively based on the assumption that FMEP is 1.2 bar at PCP of 200 bar. More details about this friction model can be found in previous work [22,23,37].…”

Section: One-dimensional Simulationsmentioning

confidence: 99%

A Simulation Study to Understand the Efficiency Analysis of Multiple Injectors for the Double Compression Expansion Engine (DCEE) Concept

Goyal

Nyrenstedt

Cabezas

et al. 2021

SAE Technical Paper Series

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“…For predicting the overall friction losses of the DCEE concept, a linear friction model was used as [23][24][25]:…”

Section: Gt-power Simulationmentioning

confidence: 99%

“…This was based on the assumption that FMEP is 1.2 bar at PCP of 200 bar. A detailed discussion of this model's selection can be found in the same work [23][24][25].…”

Section: Gt-power Simulationmentioning

confidence: 99%

“…One of the split-cycle concepts recently investigated is the double compression expansion engine (DCEE), which has achieved high thermodynamic efficiency by simultaneously reducing the exhaust and friction losses [22][23][24]. A 4-4 version of the DCEE concept is comprised of a large-size lowpressure (LP) cylinder, a small-size high-pressure (HP) cylinder, an LP tank with charge air cooler (CAC), and a cross-over channel, resulting in lower friction losses in LP cylinder, and reduced heat transfer losses in HP cylinder [22].…”

Section: Introductionmentioning

confidence: 99%

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Energy Distribution Analysis of Multiple Injectors for the Double Compression Expansion Engine Concept

Goyal¹,

Jiminez

Nyrenstedt

et al. 2021

SAE Int. J. Engines

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The present study shows the impact of multiple injectors with distinctive spray and injection angles on the engine efficiency, heat transfer, and exhaust losses. It is well known from previous studies that multiple injectors, particularly two-injectors, improve the air-fuel mixing while simultaneously reducing the heat transfer losses by keeping hot reaction zones away from the combustion cylinder walls. However, it is unclear how the spray-to-spray, umbrella, and spray-orientation angles would impact the overall energy distribution in both the combustion cylinder and double compression expansion engine (DCEE) concept. In this study, three-dimensional (3-D) Reynold-averaged Navier-Stokes (RANS) simulations were conducted in a heavy-duty single-cylinder engine, comparing three-injectors and two different side-injectors cases with a baseline case of centrally mounted single-injector. To obtain the baseline case and validate the computational fluid dynamics (CFD) data, the engine was operated at 1200 rpm, and the fuel mean effective pressure (FuelMEP) of 40 bar using conventional diesel fuel was fixed. One-dimensional (1-D) simulations then utilized the CFD-based in-cylinder pressure and rate of heat release (RoHR) traces to analyse the energy distribution of the DCEE concept. The CFD results show that the three-injectors and the best side-injectors case lead to 1.2%-points and 0.2%-points improvement of gross indicated efficiency and heat losses reduction of 1.3%-points and 2%-points, respectively, compared to the baseline single-injector case. This is due to the longer injector-wall distance from the side-injections, thereby reducing the heat transfer losses, compared to the large coverage area of the high-temperature gases for the baseline case. The 1-D results show that a high brake thermal efficiency of 53% and 52.7% can be achieved with the three-injectors and the best sideinjectors case, respectively, compared to 51.9% of the baseline case. This was due to the advanced combustion phasing, lower heat transfer losses, and higher conversion efficiency of exhaust losses from the combustion cylinder into useful work in the expansion cylinder of the DCEE concept, resulting in an overall higher engine efficiency for multiple injectors.

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Hydrogen double compression-expansion engine (H2DCEE): A sustainable internal combustion engine with 60%+ brake thermal efficiency potential at 45 bar BMEP

Babayev

Andersson

et al. 2022

Energy Conversion and Management

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Analyzing Factors Affecting Gross Indicated Efficiency When Inlet Temperature Is Changed

Cited by 12 publications

References 6 publications

A Simulation Study to Understand the Efficiency Analysis of Multiple Injectors for the Double Compression Expansion Engine (DCEE) Concept

A Simulation Study to Understand the Efficiency Analysis of Multiple Injectors for the Double Compression Expansion Engine (DCEE) Concept

Energy Distribution Analysis of Multiple Injectors for the Double Compression Expansion Engine Concept

Hydrogen double compression-expansion engine (H2DCEE): A sustainable internal combustion engine with 60%+ brake thermal efficiency potential at 45 bar BMEP

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