scholarly journals Impact of fuel chemical function characteristics on spark assisted and kinetically controlled compression ignition performance focused on multi-mode operation

Fuel ◽  
2021 ◽  
Vol 299 ◽  
pp. 120844
Author(s):  
Flavio D.F. Chuahy ◽  
Tommy Powell ◽  
Scott J. Curran ◽  
James P. Szybist
Author(s):  
P. Surendra Kumar ◽  
Venkatesh Vinjamuri ◽  
S. Geetha Priyanka ◽  
Sk. Tausif Ahamed ◽  

2021 ◽  
Author(s):  
Wei Lou ◽  
Zhongming Xiang ◽  
Wulue Pan ◽  
Aihong Tang ◽  
Wei Zhou ◽  
...  

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1064 ◽  
Author(s):  
Li ◽  
Lin ◽  
Huang ◽  
Li

In this paper, we propose a radio over fiber transmission system with simultaneous wireless multi-mode operation based on multi-wavelength optical comb and pulse shaping. This study is an initial attempt to accomplish simultaneous wireless multi-mode operation on a single optical carrier. A multi-wavelength optical comb with 13 flat optical wavelengths and space of 10 GHz is achieved by utilizing radio frequency (RF)-optics modulation and parameter configuration. The central station contains four adjacent optical wavelengths separated from the multi-wavelength optical comb by a wavelength division multiplexer, that one is modulated by 4QAM-OFDM signals with an up-converted carrier frequency of 5 GHz. The signals modulated with a single-sideband can be obtained by employing pulse shaping. The single-sideband optical signals are combined with the other three optical wavelengths and then transmitted over a standard single-mode fiber with a length of 50 km. In this arrangement, we can obtain several wireless carriers with frequencies of 5 GHz, 25 GHz, 45 GHz, and 65 GHz by direct detection. These wireless carriers are used for wireless transmission between the RF remote units and the mobile terminals. Additionally, in the radio frequency (RF) remote unit, we have three pure optical sources that can be utilized for the uplink transmission. With single channel and direct optoelectronic modulation, the optical and wireless communication with 10 Gbps can be accomplished in the whole process of system network transmission.


2012 ◽  
Vol 27 (1) ◽  
pp. 484-492 ◽  
Author(s):  
Niamh Troy ◽  
Damian Flynn ◽  
Mark OMalley

Author(s):  
Sayop Kim ◽  
Riccardo Scarcelli ◽  
Yunchao Wu ◽  
Johannes Rohwer ◽  
Ashish Shah ◽  
...  

Abstract Lean and dilute gasoline compression ignition (GCI) operation in spark ignition (SI) engines are an attractive strategy to attain high fuel efficiency and low NOx levels. However, this combustion mode is often limited to low-load engine conditions due to the challenges associated with autoignition controllability. In order to overcome this constrain, multi-mode (MM) operating strategies, consisting of advanced compression ignition (ACI) at low load and conventional SI at high load, have been proposed. In this 3-D CFD study the concept of multi-mode combustion using two RON98 gasoline fuel blends (Co-Optima Alkylate and E30) in a gasoline direct injection (GDI) engine were explored. To this end, a new reduced mechanism for simulating the kinetics of E30 fuel blend is introduced in this study. To cover the varying engine load demands for multi-mode engines, primary combustion dynamics observed in ACI and SI combustion modes was characterized and validated against experimental measurements. In order to implement part-load conditions, a strategy of mode-transition between SI and ACI combustion (i.e., mixed-mode combustion) was then explored numerically by creating a virtual test condition. The results obtained from the mixed-mode simulations highlight an important feature that deflagrative flame propagation regime coexists with ignition-assisted end-gas autoignition. This study also identifies a role of turbulent flow property adjacent to premixed flame front in characterizing the mixed-mode combustion. The employed hybrid combustion model was verified to perform simulations aiming at suitable range of multi-mode engine operations.


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