Knock characteristics and combustion regime diagrams of multiple combustion modes based on experimental investigations

Zhou, Lei; Hua, Jianxiong; Wei, Haiqiao; Dong, Kai; Feng, Dengquan; Shu, Gequn

doi:10.1016/j.apenergy.2018.07.102

Cited by 29 publications

(15 citation statements)

References 41 publications

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“…Here, the pressure value in general combustion condition is the average cylinder pressure of 200 consecutive cycles. For knock condition, the cylinder pressure is obtained at the max maximum amplitude of pressure oscillations (MAPO) cycle [44]. Along with the advance in spark timing, the maximum pressure increases gradually, until knock occurs.…”

Section: Methodsmentioning

confidence: 99%

Numerical Analysis of End-Gas Autoignition and Pressure Oscillation in a Downsized SI Engine Using Large Eddy Simulation

Zhong

Liu

2019

Energies

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Knock and super-knock are abnormal combustion phenomena in engines, however, they are hard to study comprehensively through optical experimental methods due to their inherent destructive nature. In present work, the methodology of large eddy simulation (LES) coupled with G equations and a detailed mechanism of primary reference fuel (PRF) combustion is utilized to address the mechanisms of knock and super-knock phenomena in a downsized spark ignition gasoline engine. The knock and super-knock with pressure oscillation are qualitatively duplicated through present numerical models. As a result, the combustion and onset of autoignition is more likely to occur at top dead center (TDC), which causes end gas at a higher temperature and pressure. It is reasonable to conclude that the intensity of knock is not only proportional to the mass fraction of mixtures burned by the autoignition flame but the thermodynamics of the unburned end-gas mixture, and the effect of thermodynamics is more important. It also turns out that two auto-ignitions occur in conventional knock conditions, while only one auto-ignition takes place in super-knock conditions. However, the single autoignition couples with the pressure wave and they reinforce each other, which eventually evolves into detonation combustion. This work gives the valuable insights into knock phenomena in spark ignition gasoline engines.

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Section: Methodsmentioning

confidence: 99%

Numerical Analysis of End-Gas Autoignition and Pressure Oscillation in a Downsized SI Engine Using Large Eddy Simulation

Zhong

Liu

2019

Energies

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“…By using developed in-house programming in the LabVIEW software, injection timing, pressure, and duration of DI were adjusted. A wideband lambda sensor was used to determine the overall air–fuel equivalence radio with an uncertainty of ±0.8% and the response time of 0.15 s. 33…”

Section: Setup Of Engine and Experimentsmentioning

confidence: 99%

“…The two injectors had two separate fuel supplement systems and two control units, so that different fuels can be offered by the two injection systems, which can be used concurrently or separately. Two Siemens pintle-type outward opening piezoelectric injectors were selected as direct fuel injectors, and the injector cone 33 The engine was coupled to a direct current dynamometer to maintain a constant speed of 1500 r/min with 61 r/min accuracy. The engine load was adjusted by a ZEMIC H3 C3-200 kg-3B load cell, with uncertainty of 60.5%.…”

Section: Engine and Instrumentsmentioning

confidence: 99%

Effects of the injection timing on knock and combustion characteristics in dual-fuel dual-injection engines

Liu

Kang

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part D:

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To utilize ethanol fuel in spark ignition engines more efficiently and flexibly, a new ethanol/gasoline dual-direct injection concept in gasoline engine is proposed. Therefore, based on the dual-fuel dual-direct injection system, the effects of different injection timings and two injector positions on the characteristics of combustion were studied comprehensively, and the effects of different octane numbers and temperature stratifications on knock and combustion were explored. The results show that as for Position A (ethanol injecting toward spark plug), with the delay of injection timing, knock tendency and its intensity increase initially and then decrease due to the comprehensive effect of ethanol evaporation and fuel stratification; on the contrary, for Position B (ethanol injecting toward end-gas region), retarding the injection timing of ethanol can effectively reduce the knock propensity. As for the engine performance, a dual-direct injection performs best, especially the retarded injection timing of ethanol for Position A. It can be found that with the delay of the fuel injection timing, the torque first increases and then decreases. The brake-specific fuel consumption decreases initially and then increases at maximum brake torque spark timing.

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“…Polovina et al [23] reported that fuel consumption of SACI combustion mode was ~ 5% lower than SI combustion mode along with significantly lower NOx emissions. Zhou et al [24] performed experiments using HCCI, SACI and SI combustion modes in a high compression ratio DI engine (Figure 4). They suggested a three-mode concept for smoother engine operation.…”

Section: Combustion Mode Switching In Si Enginesmentioning

confidence: 99%

Low Temperature Combustion Engines and Mode Switching Strategies – A review

Singh¹,

Ágarwal²

2018

JEES

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Rapidly increasing fossil fuel demand and deteriorating air quality have resulted in enormous pressure on automotive researchers and OEMs to develop more efficient and clean internal combustion (IC) engines. Low temperature combustion (LTC) strategies have shown significant potential of reducing oxides of nitrogen (NOx) and particulate matter (PM) emissions simultaneously without any performance sacrifice. In last few decades, researchers have resolved many issues of LTC however it's full-load application, even in light-duty engines, has not been experimentally demonstrated until now due to lack of control over ignition timing and heat release rate (HRR). This limits the commercial application of various LTC technologies in production-grade engines. To tackle this problem, an intermediate solution namely 'mode switching technique' has been demonstrated. In mode switching technique, engine operates in LTC mode up to medium loads and then switches to conventional compression ignition (CI) combustion mode to cater to higher engine loads. This dual mode combustion seems to be an effective solution for commercializing the LTC technology. This article discusses different strategies of mode switching in gasoline and diesel engines and exhibits its potential in IC engines. Use of reactivity controlled compression ignition (RCCI) combustion as LTC derivative in mode switching technique may be a future research area for development of next generation road transport vehicles.

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Knock characteristics and combustion regime diagrams of multiple combustion modes based on experimental investigations

Cited by 29 publications

References 41 publications

Numerical Analysis of End-Gas Autoignition and Pressure Oscillation in a Downsized SI Engine Using Large Eddy Simulation

Numerical Analysis of End-Gas Autoignition and Pressure Oscillation in a Downsized SI Engine Using Large Eddy Simulation

Effects of the injection timing on knock and combustion characteristics in dual-fuel dual-injection engines

Low Temperature Combustion Engines and Mode Switching Strategies – A review

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