λDSF: Dynamic Skip Fire with Homogeneous Lean Burn for Improved Fuel Consumption, Emissions and Drivability

Ortiz-Soto, Elliott; Wang, Robert; Nagashima, Masaki; Younkins, Matthew; Müller, Andreas; Tews, Sascha; Balazs, Andreas; Thewes, Matthias

doi:10.4271/2018-01-0891

Cited by 10 publications

(4 citation statements)

References 5 publications

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“…Tests performed on an in-line four-cylinder 2.0 l engine showed that the BSFC benefit can be up to 38% at two bar NMEP. The simulations of the engine with λDSF, when compared with an engine using homogeneous lean burn without CDA, showed a reduction in carbon dioxide emissions of 5.1% according to WLTC and 9.7% according to NEDC [136]. This technology can also increase average exhaust gas temperature by 20°C.…”

Section: Combination With Other Technologiesmentioning

confidence: 96%

Overview of the potential and limitations of cylinder deactivation

Fridrichová

Drápal

Vopařil

et al. 2021

Renewable and Sustainable Energy Reviews

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Section: Combination With Other Technologiesmentioning

confidence: 96%

Overview of the potential and limitations of cylinder deactivation

Fridrichová

Drápal

Vopařil

et al. 2021

Renewable and Sustainable Energy Reviews

View full text Add to dashboard Cite

“…They stated that maintenance costs for diesel buses were more (54%) than the CNG buses. In another study, Ortiz-Soto et al 15 carried out a study for Audi EA888 Gen. 3B 2.01 engine. They tried lean burn and dynamic cycle-skipping methods in the homogeneously charged engine, and they examined their effects on fuel combustion, exhaust emission, and vehicle usage.…”

Section: Literature Investigationmentioning

confidence: 99%

Cycle-skipping strategy with intake air cut off for natural gas fueled Si engine

et al. 2021

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In this study, cycle-skipping was investigated for a natural gas engine which has single cylinder, unsupercharged with 1.16 L volume and spark ignition. Additionally, inlet manifold air was switched off during cycle-skipping to minimize pumping losses. Thus, cycle-skipping strategy was carried out, and its effects on emission and engine performance were investigated. Indicated mean effective pressure, indicated efficiency, specific emissions (CO, HC, and NOX) and combustion characteristics (in-cylinder pressure and rate of heat release) were investigated in the study. As a result of performed study, it is predicted that a significant improvement can be achieved in indicated thermal efficiency as 22.8% and 13.4% by different cycle-skipping strategies. However, there is not a continuous change in emissions for different cycle-skipping strategies. While CO and NOX emissions increased in 3N1S (three normal, one cycle-skip) condition, HC emissions decreased in accordance with normal condition. For both cycle-skipping strategies, all the emissions have an increase in accordance with normal condition. In 3N1S and 2N1S (two normal, one cycle-skip) cycle skip engine operating conditions, compared to engine operating under normal condition, CO emissions increased by 14.7 and 51.7 times, respectively. In terms of HC emissions, while emission values decreased by 27.8% under 3N1S operating conditions, they increased by 67.2% under 2N1S operating conditions. Finally, in 3N1S and 2N1S cycle skip engine operating conditions, NOx emissions increased by 3.7 and 6.9 times, respectively, compared to normal operating condition. Another significant result of this study is that peak in-cylinder pressure increased as the cycle-skipping rate increased.

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“…By applying the skip-cycle strategy together with an early intake valve opening, NO x emissions are reduced by up to 40% and, with a late exhaust valve opening, a reduction of HC emissions by up to 55% is achieved. In [41][42][43][44] skipped cycles are implemented dynamically, where it is decided on a cycle-by-cycle basis if a cylinder is fired or not. This also leads to an engine fuel consumption reduction, however, a sophisticated control algorithm is required to minimize vibrations induced by the uneven firing order.…”

Section: Introductionmentioning

confidence: 99%

Increased Internal Combustion Engine Efficiency with Optimized Valve Timings in Extended Stroke Operation

et al. 2021

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Spark-ignited internal combustion engines are known to exhibit a decreased brake efficiency in part-load operation. Similarly to cylinder deactivation, the x-stroke operation presented in this paper is an adjustable form of skip-cycle operation. It is an effective measure to increase the efficiency of an internal combustion engine, which has to be equipped with a variable valve train to enable this feature. This paper presents an optimization procedure for the exhaust valve timings applicable to any valid stroke operation number greater than four. In the first part, the gas spring operation, during which all gas exchange valves are closed, is explained, as well as how it affects the indicated efficiency and the blow-by mass flow. In the second part, a simulation model with variable valve timings, parameterized with measurement data obtained on the engine test, is used to find the optimal valve timings. We show that in 12-stroke operation and with a cylinder load of 5 Nm, an indicated efficiency of 34.3% is achieved. Preloading the gas spring with residual gas prevents oil suction and thus helps to reduce hydrocarbon emissions. Measurements of load variations in 4-, 8-, and 12-stroke operations show that by applying an x-stroke operation, the indicated efficiency remains high and the center of combustion remains optimal in the range of significantly lower torque outputs.

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λDSF: Dynamic Skip Fire with Homogeneous Lean Burn for Improved Fuel Consumption, Emissions and Drivability

Cited by 10 publications

References 5 publications

Overview of the potential and limitations of cylinder deactivation

Overview of the potential and limitations of cylinder deactivation

Cycle-skipping strategy with intake air cut off for natural gas fueled Si engine

Increased Internal Combustion Engine Efficiency with Optimized Valve Timings in Extended Stroke Operation

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