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Cross-Provider Cooperation for Network-Based Localization
Published in Chao Gao, Guorong Zhao, Hassen Fourati, Cooperative Localization and Navigation, 2019
Many researchers have studied hybrid positioning schemes from the signal level, including AOA/TDOA [9], TOA/TDOA [24], and TOA/RSS [20,22]. A few studies try to combine multiple wireless technologies, such as GPS-based methods [32] and GSM/UMTS [33]. Unlike these combination schemes, the proposed approach attempts to combine the location estimations from each network provider. Connecting multiple providers is possible based on current hardware. In an emergency situation, traditional GSM devices can connect to an alternative operator other than the one for the inserted SIM card. Recently, the dual-SIM mobile phones have been developed so that users can incorporate two SIM cards into one handset. These phones have become more and more popular, and even triple-SIM phones are available from the Chinese market. This inspires us to develop cross-provider cooperation approaches to improve mobile positioning.
Semi-automatic and automatic transmissions
Published in M.J. Nunney, Light and Heavy Vehicle Technology, 2007
For the enthusiastic driver who demands a responsive car with competitive acceleration times, the Volkswagen Group in conjunction with BorgWarner introduced in 2003 what is termed their Direct Shift Gearbox, usually abbreviated to ‘DSG’. It is claimed to be able to change gear faster and more smoothly than conventional manual and automatic gearboxes, without incurring any loss of performance or fuel economy since it does not require a torque converter. This type of gearbox was first used in an Audi rally car in the mid-1980s, but it had to await the development of reliable electronic controls before its more recent application to production models. In principle the gearbox may be classified as a ‘dual-clutch’ transmission, which in this case features a divided input primary shaft flanked by two output mainshafts that connect to the final-drive gear and differential.
Some Measures Towards Enhancing the Performance of Gas-Fueled Diesel Engines at Light Load
Published in Maria da Graça Carvalho, Woodrow A. Fiveland, F. C. Lockwood, Christos Papadopoulos, Combustion Technologies for a Clean Environment, 2021
The dual fuel engine is a conventional diesel engine in which much of the energy release, and hence power, comes about from the combustion of a gaseous fuel such as natural gas/methane. Through continuing the usual timed cylinder injection of the diesel liquid fuel, ignition and the remaining part of the energy release are obtained. The introduction of the gaseous fuel is usually made through fumigation which involves its controlled continuous aspiration into the engine air by appropriate carburation equipment. More recently, increased efforts are being directed to develop intermittent electronically timed injection of the gaseous fuel into the air. This is done either just ahead of the intake valve or occasionally, directly into the engine cylinder.
Multi-objective optimization of gearshift trajectory planning for multi-speed electric vehicles
Published in Engineering Optimization, 2022
Kegang Zhao, Ziqi Li, Yuzhong Chen, Yanwei Liu
The use of electric vehicles (EVs) is an effective way to alleviate environmental and energy problems (Shin, Jung, and Oh 2017; Li et al.2018; Li, Khajepour, and Song 2019). EVs are typically equipped with single-speed transmissions, but these can hardly meet the increasing performance demand for EVs. Research shows that the application of multi-speed transmissions can effectively reduce energy consumption and considerably improve launching and acceleration performance (Urbina Coronado, Castañón, and Ahuett-Garza 2018; Liu et al.2020). For example, Sorniotti et al. (2011) demonstrated the potential advantages of a two-speed transmission for power performance and energy consumption. Among the various multi-speed transmissions, the dual-clutch transmission (DCT) has advantages such as high transmission efficiency and uninterrupted torque transfer (Walker, Zhang, and Tamba 2011; Berkel et al.2014). Thus, research on multi-speed transmissions for EVs has garnered substantial interest, and the application of the two-speed DCT in EVs is accordingly discussed in this article.
An alternative and hybrid propulsion for merchant ships: current state and perspective
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Maro Jelić, Vedran Mrzljak, Gojmir Radica, Nikola Račić
LNG (Liquefied Natural Gas) has a long history of application in the shipping sector, especially as a BOG (Boil-Off Gas) fuel for steam production on LNG carriers (Fernández et al. 2017; Huan et al. 2019). Development of dual-fuel diesel engines opens the possibility for wide usage of LNG fuel on different types of merchant vessels other than LNG carriers, Figure 11. The self-ignition temperature of natural gas stored as LNG is too high to be reached by the compression cycle in the compression ignition engine cylinder; thus, the combustion must be initiated by an ignition source. The dual-fuel engines use diesel fuel as a “pilot fuel” or as an ignition source to start the combustion process. A small amount of pilot fuel is injected into the cylinder, where it is ignited by the high temperature of the air-gas mixture at the end of the compression cycle. The amount of pilot fuel represents less than 1% of the overall energy used by the IC engine and if LNG fuel is compared to Heavy Fuel Oil (HFO), LNG greatly reduces CO2 and harmful emissions. LNG does not contain sulfur, so these emissions are eliminated completely and CO2 is reduced by 25%, while the LNG usage also reduces NOx emissions (by 40% in general) in comparison to HFO. Simultaneously, very dangerous particle emissions are reduced by 95% and even more if the LNG is used instead of HFO.
Improvement study of a low heat rejection diesel engine at part load operation in dual fuel mode
Published in Biofuels, 2018
An engine which uses conventional diesel fuel and LPG fuel is referred to as a LPG–diesel dual fuel engine. A dual fuel engine is basically a modified diesel engine in which LPG fuel, called the primary fuel, is inducted along with air. This fuel is the main source of energy input to the engine. The primary gaseous fuel is compressed with air, but does not auto ignite due to its high self-ignition temperature. A small amount of diesel, usually called the pilot, is injected, as in a normal diesel engine, at the end of compression of the primary fuel–air mixture. This pilot diesel fuel auto ignites and acts as a source of ignition for the combustion of the gaseous fuel–air mixture. Dual fuel engines can be reverted to straight diesel operation easily [10–12]. Dual fuel engines have a problem of poor brake thermal efficiency and high hydrocarbon and carbon monoxide emissions, particularly at lower loads [13,14]. To improve the performance and reduce emissions at lower loads, a low heat rejection (LHR) concept was introduced in dual fuel mode.