Optimum Heat Release Rates for a Double Compression Expansion (DCEE) Engine

Shankar, Vijai Shankar Bhavani; Lam, Nhut; Andersson, Arne; Johansson, Bengt

doi:10.4271/2017-01-0636

Cited by 22 publications

(17 citation statements)

References 7 publications

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“…The DCEE concept, introduced by Lam et al, differs from every other split-cycle engine in some aspect. Multiple numerical studies have been performed on the DCEE concept [11,12,13,14], according to which, the concept is capable of achieving a brake efficiency of…”

Section: The 4-4 Stroke Conceptmentioning

confidence: 99%

“…In addition, the inlet (blue) and exhaust (white) ports will also be modeled to provide realistic boundary conditions in the combustion chamber. Furthermore, the compressor and expander units, as well as the ports that connect them to the combustor unit of the DCEE concept, can also be modeled in 3-D to extend upon the 1-D GT-Power simulations that have already been performed [11][12][13][14].…”

Section: Future Workmentioning

confidence: 99%

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Isobaric Combustion: A Potential Path to High Efficiency, in Combination with the Double Compression Expansion Engine (DCEE) Concept

Babayev

Houidi

Andersson

et al. 2019

SAE Technical Paper Series

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Section: The 4-4 Stroke Conceptmentioning

confidence: 99%

Section: Future Workmentioning

confidence: 99%

Isobaric Combustion: A Potential Path to High Efficiency, in Combination with the Double Compression Expansion Engine (DCEE) Concept

Babayev

Houidi

Andersson

et al. 2019

SAE Technical Paper Series

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“…In the heavy-duty engine applications, one promising approach is the double compression expansion engine (DCEE) [2]. This concept divides the standard cylinder into four parts (see Figure 1), namely the high-pressure (HP) cylinder, the low-pressure (LP) cylinder, and the two cross-over tanks.…”

Section: Introductionmentioning

confidence: 99%

CFD Study of Heat Transfer Reduction Using Multiple Injectors in a DCEE Concept

Nyrenstedt

Alturkestani

2019

SAE Technical Paper Series

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Earlier studies on efficiency improvement in CI engines have suggested that heat transfer losses contribute largely to the total energy losses. Fuel impingement on the cylinder walls is typically associated with high heat transfer. This study proposes a two-injector concept to reduce heat losses and thereby improve efficiency. The two injectors are placed at the rim of the bowl to change the spray pattern. Computational simulations based on the Reynolds-Averaged Navier-Stokes approach have been performed for four different fuel injection timings in order to quantify the reduction in heat losses for the proposed concept. Two-injector concepts were compared to reference cases using only one centrally mounted injector. All simulations were performed in a double compression expansion engine (DCEE) concept using the Volvo D13 single-cylinder engine. In the DCEE, a large portion of the exhaust energy is re-used in the second expansion, thus increasing the thermodynamic efficiency. To isolate the heat losses associated with the changed spray pattern of the two-injector concept, effects of the heat release are excluded during the analysis. Results showed that the optimal injection strategy allows a decrease in the temperature close to the walls, leading to heat loss reduction up to 13 % or 2 % of the fuel energy. The residual exhaust energy was increased by 1.5 %-points with the twoinjector concept when compared to the reference case. This proved the advantage of the two-injector concept compared to conventional single injector case for the DCEE application.

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“…Another promising concept for solving the problems of the lowtemperature theory as well as keeping a high efficiency at all loads is the Double Compression Expansion Engine (DCEE) [7]. By dividing the cycle into two cylinders, this concept is capable of performing a second expansion using the spare exhaust energy.…”

Section: Introductionmentioning

confidence: 99%

Novel Geometry Reaching High Efficiency for Multiple Injector Concepts

Nyrenstedt

Andersson

2019

SAE Technical Paper Series

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Heat losses are known to decrease the efficiency of CI engines largely. Here, multiple injectors have been suggested to shrink these losses through reduction of spray wall impingement. Studies on multiple injectors have proven the concept's heat transfer reduction but also highlighted the difficulty of using a standard piston bowl. This study proposes a two-injector concept combined with a flat bowl to reduce heat losses further. To change the spray pattern, the two injectors are injecting in a swirling motion while placed at the rim of the bowl. Four injection timings have been investigated using Reynolds-Averaged Navier-Stokes simulations. This computational method quantified the amount of heat loss reduction possible. A conventional single injector concept is compared to two injector concepts with a standard and flat bowl. A Double Compression Expansion Engine (DCEE) concept, based on a modified Volvo D13 single-cylinder engine, was the base for all simulations. The DCEE can re-use the residual exhaust energy for a second expansion meaning increased importance of reduced heat losses. Heat release effects were discarded in the evaluation as an explanation for the reduced heat losses in order to isolate the effects of the changed spray pattern. Results showed a decrease in heat losses by 25.1 % or 4.2 % of the fuel energy as well as an increased IMEP of 4.5 % or 1.9 % of the fuel energy. Together with the increased exhaust energy, results showed a possible total engine efficiency increase of 2.6 % using the DCEE concept. This work successfully proves the benefits of using two injectors with a flat bowl over a standard bowl and the conventional one-injector strategy.

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Optimum Heat Release Rates for a Double Compression Expansion (DCEE) Engine

Cited by 22 publications

References 7 publications

Isobaric Combustion: A Potential Path to High Efficiency, in Combination with the Double Compression Expansion Engine (DCEE) Concept

Isobaric Combustion: A Potential Path to High Efficiency, in Combination with the Double Compression Expansion Engine (DCEE) Concept

CFD Study of Heat Transfer Reduction Using Multiple Injectors in a DCEE Concept

Novel Geometry Reaching High Efficiency for Multiple Injector Concepts

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