Lean-burn characteristics of a turbocharged opposed rotary piston engine fuelled with hydrogen at low engine speed conditions

Gao, Jianbing; Tian, Guohong; Ma, Chaochen; Zhang, Hongjie; Xing, Shikai; Jenner, Phil

doi:10.1016/j.ijhydene.2020.09.167

Cited by 24 publications

(4 citation statements)

References 65 publications

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“…The overall equivalence ratios of intake mixture over scenarios 1 and 2 were the similar (limited difference); and it was similar for scenarios 3 and 4. In this investigation, slightly higher wall temperature (650 K) was set than the authors' previous researches 29 in order to stimulate the happen of backfire. It was port fuel injected, and the air‐fuel was fully mixed at the inlet of intake ports.…”

Section: Methodsmentioning

confidence: 99%

An effective approach of dropping the backfire possibilities of a hydrogen‐fuelled opposed rotary piston engine

Gao

Tian

et al. 2021

Energy Science & Engineering

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Backfire of hydrogen‐fuelled internal combustion engines limits the hydrogen fuel applications and drops the power output. Opposed rotary piston (ORP) engines are characterized by high power density, smooth operations, and few moving parts. However, the intake structures of ORP engines tend to deliver high possibility of backfire under hydrogen utilization conditions due to more residual exhaust. This paper proposed an effective approach of eliminating backfire for a hydrogen fuelled ORP engine, and it did not generate any penalty of power output theoretically. The effectiveness of this method was demonstrated using a 3D numerical simulation method. The results indicated that the average in‐cylinder temperature started to increase at the start of the intake process if without any backfire control strategies; however, it decreased continuously if backfire control was applied. The mass flow rates of the intake fluid were at a low level without backfire control, but it increased sharply if backfire control was adopted. Backfire in this investigation was caused by the pre‐ignition of mixture in cylinders. The temperature in intake pipes reached up to 1000 K over backfire scenarios, and heat of reaction was higher than 3 W. Hydrogen mass fractions at the bottom of intake pipes were low at the start of intake process due to the backfire; meantime, slight backflow also happened in the intake process due to the pre‐ignition of cylinders mixture. The fluid velocity was higher than 100 m/s at the beginning of intake process if backfire was controlled.

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Section: Methodsmentioning

confidence: 99%

An effective approach of dropping the backfire possibilities of a hydrogen‐fuelled opposed rotary piston engine

Gao

Tian

et al. 2021

Energy Science & Engineering

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“…Compared with full engine load and stoichiometric conditions [48], slightly lean-burn technology significantly promoted the NO x formations due to more oxygen being available; additionally, the ignition timing corresponding to the highest NO x formations was affected by engine speed [48]. In the authors' previous work [9,46,47], the ignition timing was fixed (by patching high-temperature zones) under various conditions, NO x emission factors were lower than the results in this work; it was mainly caused by the differences in ignition timing, which was proved by the low efficiency of previous work. NO x emission factors were less sensitive to higher equivalence ratios of 0.7~0.9.…”

Section: Nox Emission Characteristicsmentioning

confidence: 98%

“…When a turbocharger was applied to the hydrogen ORP engine, the power density was increased to approximately 104 kW/L, and the volumetric efficiency was higher than 89.5% even for the engine speed of 5000 RPM [45]; however, NO x emission factors reached 14 g/(kW•h) over low engine speeds [45]. Equivalence ratios of 0.7~0.8 could significantly drop NO x emission factors, with a minor penalty of indicated thermal efficiency [46]. Regarding dropping NO x emission factors using lean-burn technology, naturally aspirated engines presented better performance than turbocharged engines [47].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Ignition Timing on the Emission and Combustion Characteristics for a Hydrogen-Fuelled ORP Engine at Lean-Burn Conditions

et al. 2022

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The application of hydrogen fuel in ORP engines makes the engine power density much higher than that of a reciprocating engine. This paper investigated the impacts of combustion characteristics, energy loss, and NOx emissions of a hydrogen-fuelled ORP engine by ignition timing over various equivalence ratios using a simulation approach based on FLUENT code without considering experiments. The simulations were conducted under the equivalence ratio of 0.5~0.9 and ignition timing of −20.8~8.3 °CA before top dead centre (TDC). The engine was operated under 1000 RPM and wide-open throttle condition which was around the maximum engine torque. The results indicated that significant early ignition of the ORP engine restrained the flame development in combustion chambers due to the special relative positions of ignition systems to combustion chambers. In-cylinder pressure evolutions were insensitive to early ignition. The start of combustion was the earliest over the ignition timing of −17.3 °CA for individual equivalence ratios; the correlations of the combustion durations and equivalence ratios were dependent on the ignition timing. Combustion durations were less sensitive to equivalence ratios in the ignition timing range of −14.2~−11.1 °CA before TDC. The minimum and maximum heat release rates were 15 J·(°CA)−1 and 22 J·(°CA)−1 over the equivalence ratios of 0.5 and 0.9, respectively. Indicated thermal efficiency was higher than 41% for early ignition scenarios, and it was significantly affected by late ignition. Energy loss by cylinder walls and exhaust was in the range of 10%~16% and 42%~58% of the total fuel energy, respectively. The impacts of equivalence ratios on NOx emission factors were affected by ignition timing.

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“…But, to enhance maximum thermal efficiency > 40%, reducing heat loss is essential. The effect of lean burn on decreasing cooling heat losses is greater than that of EGR [16], so higher thermal efficiency and lower emissions are expected [17][18][19][20][21]. Lean burn of an SI engine occurs when the relative air/ fuel ratio (AFR) is greater than unity.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Boost Pressure and Spark Timing on Combustion and No Emissions Under Lean Mixture Operation in Hydrogen Engines

Rrustemi

Ganippa

Axon

2023

Preprint

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Lean-burn characteristics of a turbocharged opposed rotary piston engine fuelled with hydrogen at low engine speed conditions

Cited by 24 publications

References 65 publications

An effective approach of dropping the backfire possibilities of a hydrogen‐fuelled opposed rotary piston engine

An effective approach of dropping the backfire possibilities of a hydrogen‐fuelled opposed rotary piston engine

The Effect of Ignition Timing on the Emission and Combustion Characteristics for a Hydrogen-Fuelled ORP Engine at Lean-Burn Conditions

Investigation of Boost Pressure and Spark Timing on Combustion and No Emissions Under Lean Mixture Operation in Hydrogen Engines

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