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Cold start performance of diesel engines is determined by engine design, fuel type, fuel injection strategies, lubricant and ambient temperature conditions. Prevailing emissions legislation regarding low temperature emission tests applicable for gasoline vehicles is likely to be implemented to diesel vehicles. The present research work investigates the effects of intake air heating on a Euro 5 diesel engine’s performance and exhaust emission (gaseous and particulate emissions) characteristics during the cold start followed by idling at cold ambient conditions. Heating of intake air entering the engine at cold ambient temperature conditions improved fuel combustion as well as reduced the cranking period and improved the fuel economy. More than 50% reduction in HC and 17% reduction in NOx emissions were achieved by intake air heating. Number count of accumulation mode particulates were higher during cold start compared to idle operation for all the temperature conditions. Intake air heating decreased the particulate number and size that led to reduction in total particulate mass by higher than 50% and 75% during cold start and idle respectively. The intake air heating strategy improved the cold start performance of the diesel engine at cold ambient temperature conditions and thereby would reduce the overall driving cycle emissions.

Exhaust gas recirculation (EGR) is a well known technique for suppressing knock and reducing nitrous oxide (NOx) emissions in spark-ignition engines, and this technique is now receiving more attention because of the negative effect of EGR on engine particulate emissions. This paper investigates the effect of EGR on engine combustion (in-cylinder pressure and temperature, mass fraction burned (MFB), knock limited maximum brake torque (KLMBT) spark timing, net indicated specific fuel consumption (ISFCnet), exhaust gas temperature) and emissions (NOx, unburned hydrocarbon (HC), particulate matter (PM)) in a direct injection spark ignition (DISI) engine. The tests were carried out in a single-cylinder DISI research engine with engine loads between 5.5 and 8.5 bar indicated mean effective pressure (IMEP) and various EGR ratios of up to 13%. The results show that by adding 12% EGR, the KLMBT spark timing could be advanced by 8 crank angle degrees (CAD) which resulted in a 4.1% fuel consumption reduction at 7.0 bar IMEP. EGR addition generally increased the accumulation mode particles and reduced the nucleation mode particles.

This paper studies the combustion and emission characteristics of three low octane fuels: naphtha, the blend of gasoline and diesel (G70D30), and the blend of gasoline and n-heptane (G70H30) in Multiple Premixed Compression Ignition (MPCI) mode. A commercial diesel fuel is also tested in conventional diesel combustion mode and double injection mode as a comparison. The study is carried out in a single cylinder diesel engine with a compression ratio of 16.7. By varying the common rail pressure, the effect of injection pressure on combustion and emissions is investigated. The results illustrate that the combustion delay of the gasoline-type fuels is extended with the increase of injection pressure. The soot emission decreases at high injection pressure with a penalty of higher CO and HC emissions. Increasing the injection pressure also reduces the particle number in accumulation mode, but produces more in nucleation mode. Among the test fuels, naphtha has the lowest NOx emission due to low combustion temperature but the highest CO and HC emissions. There is no significant difference in particle size distribution for the three fuels. The indicated thermal efficiency of gasoline-type fuels increases with the rise of injection pressure and is higher than that of diesel at high injection pressure. Naphtha has the highest efficiency as a result of its low heat transfer and exhaust loss. The diesel fuel has lower CO and HC emissions than the gasoline-type fuels do, but much higher pressure rise rate, NOx and soot emissions due to high combustion temperature and poor premixing. Therefore, the low octane gasoline fuels are more suitable than the diesel for compression ignition engines in terms of the emissions.

Objectives: To retrospectively describe our 10-year experience with extracranial non-vestibular head and neck schwannomas by presenting their clinical features, diagnostic methods, surgical decisions, and treatment outcomes. Methods: This is a retrospective study conducted at the Department of Otolaryngology, Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Shanghai First People’s Hospital, Shanghai, China. The medical records of 46 patients diagnosed with schwannoma in the extracranial head and neck region as confirmed on paraffin-embedded sections from January 2003 to December 2012 were reviewed. Results: All tumors were benign, and 52% presented as asymptomatic palpable solitary masses. Compressive symptoms, which can represent meaningful indicators of the nerve of origin were commonly noted. The most common nerve of origin was the brachial plexus (n=13, 28.3%). Conclusion: While postoperative histopathologic examination is still the gold standard, fine needle aspiration cytology, CT scan, and magnetic resonance imaging may be useful in the diagnosis of schwannomas. As schwannomas are radioresistant, and as, despite their benign nature, can cause severe secondary symptoms, the best treatment of choice is complete excision with preservation of functions. Saudi Med J 2015; Vol. 36 (11): 1363-1366 doi: 10.15537/smj.2015.11.12314

An investigation of hydrocarbon (HC) and aldehyde emissions from the combustion of 2-methylfuran (MF) was conducted, with samples taken from the exhaust of a single cylinder direct-injection spark ignition (SI) research engine. This article validates the mechanism of MF combustion, and assesses its toxic emissions. Aldehyde emissions from MF were quantitatively measured using high performance liquid chromatography, and the results were compared with those of gasoline, 2,5-dimethylfuran (DMF), ethanol, methanol, and n-butanol. The detected aldehydes were mainly formaldehyde and acetaldehyde. Reaction pathway analyses of the combustion of MF and DMF were performed using a closed homogeneous constant volume reactor model in the Chemkin package. The formaldehyde emission was related to the side chain of MF. It was only half that of DMF and it was much lower than those of other fuels. The acetaldehyde emission from MF was also one of the lowest among all tested fuels. HCs from MF combustion were qualit...

Controlling fuel injector deposits is recognized as a challenge for advanced direct-injection spark-ignition (DISI) engines. This paper gives a comprehensive overview of the research on formation, measurement, effect, and mitigation of injector deposits in DISI engines. Methodologies for the injector deposit studies include visual and compositional analysis. It is shown that injector deposits will reduce injector fuel flow rates, and lead to changes in spray characteristics. Consequently, spray angle and envelope are likely to be affected, and spray penetration distance as well as droplet diameter can be increased. Injector deposits are revealed to be primarily fuel-derived and created by two distinct free radical pathways, i.e., low temperature auto-oxidation and high temperature pyrolysis. Fuel compositions (olefins, aromatics, and sulphur), as well as T90 parameter, are significant factors in injector deposit formation. The worst consequences of injector fouling are pre-ignition, and engine misfiring and malfunction. Emissions, especially particulates, dramatically increase as the fuel injector becomes fouled. It appears that fuel detergent is the most effective method in controlling injector deposit formation if its chemistry and dosage rate are optimized. Outward opening piezo-driven injector configuration with a good surface finish, a sharp nozzle inlet, and a counter bore design, is useful in preventing injector deposit formation. Reducing injector nozzle temperature by methods such as designing special injector cooling passages, and improving engine design are also proven to be helpful in reducing injector fouling. Anti-deposit coatings only delay the onset of injector deposit formation.

An advanced combustion strategy namely “multiple premixed compression ignition” (MPCI) can exploit multiple combustion regimes. In this paper, the two-stage premixed combustion (i.e. low-temperature combustion and high-temperature combustion) using relatively low-reactivity and high volatility fuel is uncovered in MPCI mode. The mixture formation and combustion processes of low-octane gasoline MPCI mode is resolved by KIVA–CHEMKIN. The low-octane gasoline (G70H30) modeled in this study is a mixture of 70% gasoline and 30% n-heptane by volume, and it is represented by iso-octane and n-heptane oxidation mechanism. A discrete multi-component (DMC) vaporization model is used to simulate the evaporation process of G70H30, while a simplified 12-step GRI-Mech model and a two-step soot model are applied for the NOx and soot calculation, respectively. As a comparative study, partially premixed compression ignition (PPCI) mode of G70H30 is also simulated using the same numerical models. From the longitudinal and transverse sections of the combustion chamber, temporally and spatially distributed combustion events are found in the MPCI mode. That is to say, the first low temperature premixed compression ignition occurs outside of the piston bowl, and it occurs mainly in the squeeze zone above the piston triggered by the local fuel rich region. Then the second high temperature premixed combustion, which is controlled by the local turbulence resulting from the second fuel injection and chamber wall interaction, is located in the center of the combustion chamber. The temporally and spatially distributed combustion in MPCI mode decreases the local temperature, resulting in less NOx formation and lower heat transfer losses. However, there is no marked combustion distribution phenomenon in the G70H30 PPCI mode, and more NOx is generated due to higher local temperature. In addition, the early first injection of MPCI and PPCI causes spray-liner impingement, and becomes the main source of soot formation in the subsequent combustion processes.

The tribological behaviour of pyrolysis bio-oil with a synthesized nano-Lanthanum oxide (La2O3) additive was evaluated using a point contact four ball tribometer under different frictional conditions. Results were compared against a micro (μ)-La2O3 additive and an un-additised bio-oil as a control. The results show that nano-La2O3 impregnated bio-oil had better tribological properties than the control groups. Under the operating loads, the optimum nanoparticle concentration within the bio-oil was investigated. At these levels, the combined action of adsorbed bio-oil films on the worn surfaces and the bearing effects of the nano-La2O3 minimized friction and wear. The tribo-mechanisms were ascribed to adhesive wear as a result of lubrication starvation under high loads, and abrasive wear at high rotational speeds as a result of combined deformation and aggregation of the nano-La2O3 particles.

The injection and combustion characteristics are complicated when split injection strategy is used due to strong interaction between splits. Various injection tests were carried out with long tube real-time fuel flow measuring instrument by employing both single and split injection strategies. Many engine tests with selected operation points (various pilot injection quantities, various injection dwells and various numbers of split injections) were also carried out with split injection strategy, enabling the combination of mass flow rate (MFR) and heat release rate (HRR) information to study combustion features. The results showed that raised injection pressure shortened the injection delay and increased the MFR. The actual injection duration was much longer than the TTL duration. More importantly, for multiple injections, the interaction between splits was dominated by the duration of the first split and injection intervals. The number of splits also exerted profound influence on the interaction. In addition, higher MFR for pilot injection near the piston TDC adversely affected the HRR and normalized combustion efficiency. Increased split injections with low MFR can effectively lower the peak HRR thus reducing the maximum temperature and NOx emissions.

Studies on fuel flow characteristics under both room temperature (25 °C) and low temperature (− 18 °C) were carried out under a wide range of injection pressures and back pressures using a long tube real-time fuel flow rate measuring instrument. Both single and split injection strategies were employed. Several modified correlations were proposed to analyze fuel injection characteristics. It was found that low fuel temperature caused longer injection delay, shorter injection duration, lower mass flow rate and less injected fuel mass. The injector discharge coefficient was affected more by fuel viscosity changes due to low temperature than by the geometric structure of the injector. Cold start conditions effectively limited the inception of cavitation as seen in the flow rate/pressure dependence and accelerated the transition of flow regime from cavitation to turbulent and laminar flow with the decrease of injection pressure. This contributed to increased chances for the existence of laminar flow and thus to reduction of the discharge coefficient. Besides, low fuel temperature significantly weakened the degree of interaction between individual parts of split injection and split mass flow rate shapes became much less continuous than those under room temperature. These findings are of great importance for engine cold start studies.

Data and methods additional to the main manuscript

Many environmental samples, including water, soils, sediments and airborne particles and vapours contain complex mixtures of hydrocarbons, often deriving from crude oil either before or after fractionation into fuels, lubricants and feedstocks. Comprehensive 2D Gas Chromatography- Time-of-Flight Mass Spectrometry (GC &times GC-ToFMS), offers a very powerful technique separating and identifying many compounds in complicated hydrocarbon mixtures. However, quantification and identification of individual constituents at high ionization energies would require hundreds of expensive (if available) standards for calibration. Although the chemical structure of hydrocarbons does matter for their environmental impact and fate, strong similarities can be expected for compounds having very similar chemical structure and carbon number. There is, therefore, a clear benefit in an analytical technique which is specific enough to separate different classes of compounds, and to distinguish homologous series, whilst avoiding the need to handle each isomer individually. Varying EI (electron impact) ionization mass spectrometry significantly enhances the identification of individual isomers and homologous compound groups, which we refer to as isomer sets. Advances are reported in mapping and quantifying isomer sets of hydrocarbons (≥ C12) in diesel fuel, lubricating oil and diesel exhaust emissions. Using this analysis we report mass closures of ca. 90 % and 75 % for diesel fuel and lubricating oil.

Over the past 20 years, with the increase in the complexity of engines, and the combinatorial explosion of engine variables space, the engine calibration process has become more complex, costly, and time consuming. As a result, an efficient and economic approach is desired. For this purpose, many engine calibration methods are under development in original equipment manufacturers and universities. The state-of-the-art model-based steady-state design of experiments (DOE) technique is mature and is used widely. However, it is very difficult to further reduce the measurement time. Additionally, the increasingly high requirements of engine model accuracy and robust testing process with high data quality by high-quality testing facility also constrain the further development of model-based DOE engine calibration. This paper introduces a new computational intelligence approach to calibrate internal combustion engine without the need for an engine model. The strength Pareto evolutionary algorithm 2 (SPEA2) is applied to this automatic engine calibration process. In order to implement the approach on a V6 gasoline direct injection (GDI) engine test bench, a simulink real-time based embedded system was developed and implemented to engine electronic control unit (ECU) through rapid control prototyping (RCP) and external ECU bypass technology. Experimental validations prove that the developed engine calibration approach is capable of automatically finding the optimal engine variable set which can provide the best fuel consumption and particulate matter (PM) emissions, with good accuracy and high efficiency. The introduced engine calibration approach does not rely on either the engine model or the massive test bench experimental data. It has great potential to improve the engine calibration process for industries.

This study aimed to retrospectively investigate the factors related to pediatric obstructive sleep apnea–hypopnea syndrome (OSAHS) with attention deficit hyperactivity disorder (ADHD) in children younger than 6 years and those older than 6 years. A total of 437 children who were hospitalized due to OSAHS between January 2014 and December 2014 were retrospectively reviewed. The children were further divided into OSAHS group and OSAHS + ADHD group. The general characteristics, OSA-18 quality of life, intention-hyperactivity score, and polysomnographic parameters (apnea–hypopnea index and the lowest oxygen saturation) were collected and compared between groups. There were 298 boys and 139 girls with the male to female ratio of 2.14:1. ADHD was found in 146 children including 105 boys and 41 girls with the male to female ratio of 2.56:1. Of these children, 31.62% and 35.46% had concomitant ADHD in children aged 4 to 5 years and those aged 6 to 11 years, respectively. In children aged 4 to 5 years, the incidence of allergic rhinitis was significantly higher (P = .016) and the adenoid hypertrophy was more severe (P = .001) in those with concomitant ADHD. In children aged 6 to 11 years, the tonsil hypertrophy was more severe in those with concomitant ADHD (P = .019). In children with concomitant ADHD, OSA-18 score was higher than in those with OSAHS alone (P

The trend in the automotive industry is towards electric vehicles (EV), however, the industry will depend on gasoline engines for many years to come. There is also increased demand for the reduction of greenhouse gases. This work develops an adaptive model-based optimal control algorithm based on Sub-Structured Neural Network (SSANN), Multi-Objective Genetic Algorithms (GA), Multi-Objective Dragonfly Algorithm (MODA) and a fuzzy based inference system. The SSANN based on an individual engine speed are combined into a SSANN, whose output is connected to a fuzzy based inference system which extrapolates between trained engine speeds. The SSANN outputs are then used to evaluate the objective function of the optimisation process, which is performed using GA and MODA. The SSANN is retrained if the error is out of defined limit, which allows the system to adapt with engine ageing. The purpose of this work is to contribute to online engine calibration and control to improve engine performance and reduce greenhouse gas emissions.

This paper presents a computer-aided technique for automated analysis and classification of melanocytic tumor on skin whole slide biopsy images. The proposed technique consists of four main modules. First, skin epidermis and dermis regions are segmented by a multi-resolution framework. Next, epidermis analysis is performed, where a set of epidermis features reflecting nuclear morphologies and spatial distributions is computed. In parallel with epidermis analysis, dermis analysis is also performed, where dermal cell nuclei are segmented and a set of textural and cytological features are computed. Finally, the skin melanocytic image is classified into different categories such as melanoma, nevus or normal tissue by using a multi-class support vector machine (mSVM) with extracted epidermis and dermis features. Experimental results on 66 skin whole slide images indicate that the proposed technique achieves more than 95% classification accuracy, which suggests that the technique has the potential to be used for assisting pathologists on skin biopsy image analysis and classification.

Injector deposit is a common phenomenon for gasoline direct injection (GDI) engines that greatly affects the spray behavior and consequently the combustion performance and emissions. In this study, the deposit effect on the inner nozzle flow dynamics was numerically investigated. High resolution X-ray scan was performed first to obtain realizable information regarding to the nozzle and deposit morphologies and topology. Simulation was then carried out in the Large Eddy Simulation (LES) framework with cavitation taken into account by a homogeneous equilibrium model (HRM). It was found that the rough surface of deposit would lead to additional cavitation inception inside the counterbore and restrict the flow area, causing losses in the mass flow rate. Deposit inside the counterbore acted as an extension to the inner orifice and restricted the air recirculation, which was believed to be the cause of poor atomization of coked injector spray.

Cavernous malformation or cavernoma is a kind of brain vessel abnormality that can cause serious symptoms such as seizures, intracerebral hemorrhage and various neurological deficits. It is one of the most common epileptogenic lesions that can be identified by physicians based on magnetic resonance imaging (MRI) of the brain. However, visual detection of cavernomas in a large set of brain MRI slices is a time-consuming task. This paper proposes a computer aided cavernomas detection method based on T2-weighted MRI analysis. The proposed method includes the following steps: template matching to find suspected cavernoma regions and classification based on support vector machines (SVMs) to remove most of the false positives. The performance of the proposed technique is evaluated and a sensitivity of 0.96 is obtained after testing.

In recent years, particulate emissions from the gasoline direct injection (GDI) engine, especially the ultrafine particulates, have become a subject of concern. In this study, the impact of fuel (gasoline versus ethanol) and injection system (injection pressure and injector condition) on particle emissions was investigated in a single cylinder spray-guided GDI research engine, under the operating conditions of stoichiometric air/fuel ratio, 1500 rpm engine speed and 3.5–8.5 bar IMEP. The results show that, in a spray guided GDI engine, ethanol combustion yields much lower particle mass (PM) but higher particle number (PN) emissions, compared to gasoline. Depending on the fuel used, the PM and PN emissions respond differently to injection pressure and injector condition. For gasoline, the injection system has a significant impact on the PM and PN emissions. High injection pressure and clean injector condition are both essential for low particle emissions. Compared to gasoline, the particle emissions from ethanol combustion is less sensitive to the injection system, due to its higher volatility and diffusive combustion which produces less soot. Furthermore, a PM and PN trade-off was observed when using gasoline and ethanol, and when using high injection pressures.

Flame-induced auto-ignition (FIAI), where spark-triggered flame propagation causes auto-ignition without engine knock, is one of the promising high-efficiency combustion modes. FIAI and SI knocking combustion have several similarities; however, the former is beneficial to thermal efficiency, and the latter should be avoided for engine safety. This study investigates the flame structures, intermediate species and pressure evolution during FIAI and SI knocking combustion using an optical engine with ultra-high speed imaging of CH 2 O and OH chemiluminescence. The flame structures are analyzed together with cylinder pressure and intermediate species to understand their dynamic interactions. Findings reveal that auto-ignition in FIAI begins from the outer rim of the SI flame front; the reaction front propagates at a speed of approximately 160 m/s, which is more than one order higher than the speed of normal flame propagation. The reaction front propagates in subsonic speed. The propagation regime changes from normal flame propagation to reaction front propagation at approximately 795 K for n-heptane. The temperature of the unburned zone and the remaining energy are the key factors for the occurrence of knocking; they also differentiate FIAI from typical knocking.

A four-ball tribological test was used to investigate the effects of a TiF 3 catalyst on the tribological behaviors of biofuel soot (BS)-contaminated liquid paraffin (LP). The effects of load and rotational speed were studied as well. Scanning electron microscopy with energy-dispersive spectroscopy and X-ray photoelectron spectroscopy were conducted to investigate surface element content and chemical valence state, respectively. Results showed that the extreme pressure properties of BS-contaminated LP were all promoted with or without the presence of 0.5 wt% TiF 3 . The TiF 3 catalyst material significantly contributed to the antiwear and the antifriction properties of LP with or without BS contamination. These results were caused by the decomposition of the TiF 3 catalyst into TiO 2 and fluoride (FeF 2 ) which improved the lubricity.

The non-volatile particle emission characteristics of alternative (rapeseed methyl ester and gas-to-liquid) diesel fuel blends were studied through an experimental investigation carried out on a light-duty common-rail diesel engine. A blend ratio of 10 vol % was chosen as the practical limit for biodiesels in this study, and the research focus was on the particle number concentration and size distribution with various injection strategies, in which the non-volatile emissions were measured using thermodilution. The particle morphology and mass, together with the related gaseous emissions, were measured and analysed. The results indicate that, without any engine modification, adding selected alternative fuels even at a low percentage could result in a favourable reduction in the number of particles and in a significant reduction in the total particle concentration in both the nucleation mode and the accumulation mode. The particle emissions of the three fuels demonstrated monomodal size distributions under most engine conditions tested, except for the engine idling case, which produced a bimodal size distribution. The influence of 10 vol % rapeseed methyl ester or gas-to-liquid diesel blends on the carbon monoxide and nitrogen oxide emissions is not significant. Nevertheless, using these diesel fuel blends may increase the total hydrocarbon emissions and may lead to high particulate matter emissions.

The furan series of chemicals such as 2,5-dimethylfuran (DMF) and 2-methylfuran (MF) are promising alternative fuel candidates for internal combustion engines due to their advantages compared to gasoline. However, no research has been published on the optical diagnostics of their combustion process in the engine cylinder. In this paper, the planar laser-induced fluorescence (PLIF) technique has been used to investigate the OH distribution in the flames of DMF and MF in a direct injection spark ignition (DISI) optical engine. The images of OH-LIF in the combustion process combined with the high-speed imaging and heat release data at two different engine load conditions (4.5 bar and 5.5 bar IMEP) for DMF and MF were studied and compared with isooctane, the reference fuel representing gasoline. Interesting correlations were found between the heat release rate, flame speed, flame area and PLIF of OH for the tested fuels at the two loads and the proposed correlations have also been confirmed by using the data in previous studies. MF is shown to combust significantly faster than DMF and isooctane. It is found that at 4.5 bar IMEP, the pressure trace, flame speed and flame area growth rate of DMF are very close to those of isooctane, but lower than those of MF. The combustion phase of MF is earlier and the duration is shorter than DMF and isooctane. Normalized LIF signals show that MF always has the maximum values and the higher IMEP will advance the time of the OH peak. The rate of heat release (ROHR) matches the trend of OH development well before the flame goes beyond the visible area. Finally, a correlation between the results of MFB and OH-LIF reveals that the three fuels follow a similar trend, indicating that the OH generation matches the MFB data well, irrespective of the fuel. The correlations between the flame area and OH-LIF signal are also discussed.

The tribological response of bio-oil derived from Spirulina algae has been assessed, according to the choice of catalyst during esterification. The bio-oil was upgraded over the selected catalysts of KF/HZSM-5 and KF/Al 2 O 3 with ethanol. Physical and chemical properties were assessed throughout with the crystal structure of the catalysts was characterized by X-ray diffraction (XRD), chemical groups and components of the bio-oil by Fourier Transform infrared spectroscopy (FTIR) and Gas Chromatograph–Mass Spectroscopy (GC–MS). Tribological experiments were conducted using a bespoke piston ring-on-cylinder liner tribometer. Worn surfaces were observed by Scanning Electron Microscope (SEM), and the elemental contents and valences were tested by X-ray Energy Dispersive Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS). It is shown that choice of catalyst used during the upgrading of the bio-oil has a significant effect on tribological performance. Catalytic esterification improved friction resistance and the anti-wear properties of the bio-oil. KF/Al 2 O 3 was a better catalyst for doing this than KF/HZSM, a result of the ester and organic groups present in the KF/Al 2 O 3 upgraded bio-oil. These groups acted to form a protective tribo-film between surfaces.

Primary combustion intermediates in low-pressure premixed laminar 2,5-dimethylfuran (DMF)/oxygen (O2)/argon (Ar) flames with equivalence ratios of 0.8 and 1.5 were investigated by using tunable synchrotron vacuum ultraviolet photoionization and molecular-beam mass spectrometry. DMF is a promising biofuel, with properties similar to those of gasoline. However, the combustion chemistry of DMF is not well-studied. Possible reaction pathways of DMF and its primary combustion derivatives were proposed based on the combustion intermediates identified in this work. Photoionization efficiency curves (PIEs) of the combustion intermediates in the DMF/O2/Ar flames were recorded. Ionization energies (IEs) were measured from the PIEs. The combustion intermediates were identified by the agreement of the measured IEs with those reported in the literatures or calculated at G3B3 level. H abstraction and the consecutive reaction products were identified, including 5-methylfurfural, (Z)-1-oxo-1,3,4-pentatriene, and 2-ethyl-...

The energy management system of an electrified vehicle is one of the most important supervisory control systems which manages the use of on-board energy resources. This paper researches a ‘model-free’ predictive energy management system for a connected electrified off-highway vehicle. A new reinforcement learning algorithm with the capability of ‘multi-step’ learning is proposed to enable the all-life-long online optimisation of the energy management control policy. Three multi-step learning strategies (Sum-to-Terminal, Average-to-Neighbour Recurrent-to-Terminal) are researched for the first time. Hardware-in-the-loop tests are carried out to examine the control functionality for real application of the proposed ‘model-free’ method. The results show that the proposed method can continuously improve the vehicle’s energy efficiency during the real-time hardware-in-the-loop test, which increased from the initial level of 34% to 44% after 5 h’ 35-step learning. Compared with a well-designed model-based predictive energy management control policy, the model-free predictive energy management method can increase the prediction horizon length by 71% (from 35 to 65 steps with 1 s interval in real-time computation) and can save energy by at least 7.8% for the same driving conditions.

The effect of N2 and CO2 dilution on MTHF/air premixed flame propagation was investigated at initial temperature and pressure of 393 K and 0.1 MPa, respectively. The flame speed measurements were conducted on spherically expanding premixed flame in a constant volume vessel using high speed Schlieren technique. The level of dilution was varied from 5 to 15% at equivalence ratio (ϕ) ranging from 0.8 to 1.5. CO2 has a larger impact on flame speed reduction than N2, where the peak flame speed at ϕ = 1.1 dropped from 0.58 m/s to 0.44 m/s and then to 0.24 m/s as the CO2 dilution increased from 0% to 15%. Markstein length was found to increase with dilution in the premixed flames which could be attributed to the decrease in the probability of hydrodynamic instability owing to increasing flame thickness especially for rich conditions. Numerical simulations using two detailed kinetic mechanisms showed good agreement with the experimental measurements. Comparison between the kinetic effects and physical dilution effects of CO2 on flame speed showed that the latter dominated overall, with the relative contribution of kinetic effects being highest for Φ = 1.1. Reverse CO + OH ⇔ CO2 + H was identified as the key reaction directly affected by CO2 dilution leading to CO2 dissociation and H consumption. The competition for H radical with primary chain branching/propagating reactions hindered the MTHF/air combustion in CO2 diluted flames.

This paper investigates an online predictive control strategy for series-parallel plug-in hybrid electric vehicles (PHEVs), resulting in a novel online optimization methodology named the dual-loop online intelligent programming (DOIP) that is proposed for velocity prediction and energy-flow control. By reconsidering the change of driving behaviours at each look-ahead step, this methodology guarantees the effectiveness of optimal control sequence in the energy-saving efficiency of online predictive energy management. The design procedure starts with the simulation of a series-parallel PHEV using a systematic control-oriented model and the definition of a cost function. Inspired by fuzzy granulation technology, a deep fuzzy predictor is created to achieve driver-oriented velocity prediction, and a finite-state Markov chain is exploited to learn transition probabilities between vehicle speed and acceleration. To determine the optimal control behaviours and power distribution between two energy sources, chaos-enhanced accelerated swarm optimization is developed for the DOIP algorithm. The prediction capability of the deep fuzzy predictor is evaluated by comparing with two existing predictors over the WLTP-based driving cycle. The proposed control strategy is contrasted with short-sighted and dynamic programming based counterparts, and validated by a driver-in-the-loop test. The results demonstrate that the deep fuzzy predictor can effectively recognize driving behaviour and reduce at least 19% errors compared to involved Markov chain based predictors. Online predictive control strategy using the DOIP algorithm is able to significantly reduce 9.37% fuel consumption from the baseline and shorten computational time.

Study design clinical results of A STROBE-compliant retrospective study OBJECTIVE:: To achieving adequate pharyngeal closure and improve the pharyngeal function by a modified two-flap palatoplasty. Summary of background Excessive tension in soft palate is the main factor causing the dysphonia after cleft palate. The tension-free suture of the soft palate is the key to achieving adequate pharyngeal closure. In this paper, a modified two-flap palatoplasty improved the pharyngeal function METHODS:: From August 2016 to December 2017, 20 patients with cleft palate were treated with a modified two-flap palatoplasty of the posterolateral symmetrical mucosal relaxation incision. The mucosal relaxation incision was performed on both posterolateral sides of the soft palate. Results All cases had good healing of mucosal flap and the palate. All patients underwent endoscopic examination at 6 months after operation. The postoperative results were satisfactory, with no complications. Twelve patients had bilateral exudative otitis media before operation, 4 patients returned to normal postoperatively, and 8 patients underwent bilateral tympanic membrane catheterization; 2 patients had abnormal function of bilateral eustachian tube before operation and returned to normal postoperatively; 3 patients had unilateral exudative otitis media before operation, and all of them returned to normal; the acoustic impedance test was normal in 3 children before operation. Most children begin to learn to speak, parents are satisfied with their pronunciation, and 3 children are in speech rehabilitation due to unclear pronunciation. Conclusions We propose a technique to improve the function of the velopharyngeal closure which effectively reduces the incidence of pharyngeal insufficiency and occurrence of operative correction of pharyngeal closure dysfunction. The modifed two-flap palatoplasty with posterior lateral symmetric mucosal relaxation incision is beneficial for better velopharyngeal closure.

This paper studies the combustion and emission characteristics of three kinds of low octane fuels which are naphtha, the blend of gasoline and diesel (G70D30), the blend of gasoline and n-heptane (G70H30) in multiple premixed compression ignition (MPCI) mode. Commercial diesel is also tested in conventional diesel combustion mode as a reference. The study is carried out in a single cylinder diesel engine with a compression ratio of 16.7. By varying the common rail pressure, the effect of injection pressure on combustion and emissions is investigated. The results illustrate that the combustion delay of the gasoline-type fuels is extended with the increase of injection pressure. The soot emission decreases at high injection pressure with a penalty of higher CO and HC emissions. Increasing the injection pressure also reduces the particle number in accumulation mode, but produces more in nucleation mode. Among the test fuels, naphtha has the lowest NO x emission due to low combustion temperature but the highest CO and HC emissions. There is no significant difference in particle size distribution for the three fuels. The indicated thermal efficiency of gasoline-type fuels increases with the rise of injection pressure and it is higher than that of diesel at high injection pressure. The diesel fuel has lower CO and HC emissions than the gasoline-type fuels, but much higher pressure rise rate, NO x and soot emissions due to high combustion temperature and poor premixing. Therefore, the low octane gasoline fuels are more suitable than the diesel for the compression ignition engines in terms of the emissions.

Stoichiometric Diesel and Gasoline Dual-fuel (Dieseline) Compression Ignition (SDCI) combustion using three-way catalyst (TWC) after-treatment is a promising technology to address the challenge issues of fuel consumption and emissions in future internal combustion engines. The authors use EGR instead of the throttle to control the load of the dual fuel compression ignition combustion engine. In order to investigate the fuel consumption and emission characteristics of SDCI combustion, a series of experiments were conducted in a modified single cylinder diesel engine using gasoline with a small portion of diesel for ignition enhancement. The experimental results show that SDCI combustion can achieve high indicated thermal efficiencies in a relatively wide range of loads (IMEP 4.3–8.0 bar) because of a higher compression ratio, shorter combustion and smaller pumping losses. An attractive indicative specific fuel consumption (ISFC) of 190.8 g/kW h has been achieved at a medium load without any boosting and the PM emissions are lower than for conventional diesel combustion. Different diesel percentages in the dual fuel supply have shown a significant impact on the ignition process and provide a wider available time range for combustion phase control. Diesel direct injection (DI) timing has a greater effect on PM emissions than the fuel ratio. Late DI timing reduces the thermal efficiency and results in higher PM emissions. Early DI timing and less diesel are preferable in order to reduce or avoid the diffusion combustion stage, which may lead to high PM emissions in the stoichiometric combustion.

Double injection strategies with single-stage heat release and two-stage heat release process of straight-run naphtha were investigated on a single-cylinder diesel engine from low to high load. The two-stage combustion strategy is realized by split spray and combustion events around the compression top dead center with a dominant feature of “Combust After Injection End, Inject After Combustion End” to ensure the premixed compression ignition. The single-stage combustion is realized by the “spray–spray–combustion” process with the start of combustion separated from the end of injection. The straight-run naphtha has a research octane number of 58.8, and the compression ratio and displacement of the test engine are 16.7 and 0.5 L. Double injection strategy is used to generate the single- and two-stage combustion modes with different injection timing. NOx and total hydrocarbon emissions of the two-stage combustion mode are lower than that of single heat release mode in this study, and it is much easier to produce two-stage combustion mode at higher engine load. Diesel is also tested under double injection strategy just as the single heat release mode of straight-run naphtha, but the fuel efficiency and emission performance are worse than that of naphtha.

The effects of a TiF3 catalyst on the tribological behaviour of carbon black-contaminated liquid paraffin and a fully formulated engine lubricating oil (CD SAE15W-40) were investigated using a four-ball tribological test. Scanning electronic microscopy with energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, surface roughness, and thermogravimetric analyses were used to investigate the surface element content, chemical valence state, surface roughness, and initial decomposition temperature of the oil samples, respectively. Results showed that the average wear scar diameter (AWSD) and friction coefficient of the two kinds of carbon black-contaminated lubricants decreased in the presence of 0.5wt% TiF3. The variation rates of the carbon black-contaminated liquid paraffin and fully formulated engine lubricating oil were 29.45% and 11.54%, respectively, and their initial decomposition temperatures decreased. These phenomena were ascribed to the decomposition of TiF3 catalyst into TiO2 and fluoride that resulted in the formation of improved boundary lubrication films. Moreover, for the fully formulated engine oil, the lubrication additive zinc dialkyldithiophosphate was catalyzed by TiF3, decomposing into polyphosphate, which aided the formation of mixture boundary lubrication films.

This paper describes a study of the influence of soot contamination on the tribological behavior of engine lubricants. The candidate lubricants were a formulated engine lubricant, (CD SAE 15W-40) and a base oil (150SN). Soot particle contamination was simulated using carbon black with friction and wear measured using a four-ball tribometer. The results show that the antiwear and antifriction properties of the CD SAE 15W-40 formulated oil with varying carbon black contents were better than those of 150SN base oil. The antifriction properties of the SAE 15W‐40 formulated oil with the addition of 2 wt% carbon black were strengthened. This was ascribed to uniformly dispersed carbon black and the additives in the CD SAE 15W-40. The antifriction properties of the 150SN base oil with 2, 4 wt% carbon black content were upgraded via the addition of 2 wt% dispersant polyisobutylene succinimide. The tribological effect of the carbon black in the lubricants was attributed to absorption and agglomerate effects. & 2013 Published by Elsevier B.V.

Studies investigating the association between interleukin-13 (IL-13) single nucleotide polymorphism (SNP) rs20541 and allergic rhinitis (AR) risk have reported conflicting results. The aim of the present study was to conduct a meta-analysis assessing the possible association of IL-13 SNP rs20541 with AR risk. Eight studies were included in the present meta-analysis (2153 cases and 3931 controls). The combined results based on all studies showed that IL-13 SNP rs20541 was associated with increased AR risk (Gln versus Arg: odds ratio (OR) = 1.18, 95% confidence interval (CI) = 1.08–1.30; Gln/Gln versus Arg/Arg: OR = 1.52, 95% CI = 1.20–1.92; Arg/Gln + Gln/Gln versus Arg/Arg: OR = 1.19, 95% CI = 1.06–1.33; Gln/Gln versus Arg/Gln + Arg/Arg: OR = 1.42, 95% CI = 1.13–1.79). When stratifying for race, IL-13 SNP rs20541 exhibited increased AR risk in Asians (Gln versus Arg: OR = 1.20, 95% CI = 1.06–1.36; Gln/Gln versus Arg/Arg: OR = 1.57, 95% CI = 1.17–2.12; Arg/Gln + Gln/Gln versus Arg/Arg: OR = 1.22, 95% CI = 1.04–1.44; Gln/Gln versus Arg/Gln + Arg/Arg: OR = 1.45, 95% CI = 1.09–1.93), while no significant association was detected in Caucasians (Gln versus Arg: OR = 1.28, 95% CI = 0.93 ~ 1.78; Gln/Gln versus Arg/Arg: OR = 1.42, 95% CI = 0.96–2.11; Arg/Gln + Gln/Gln versus Arg/Arg: OR = 1.35, 95% CI = 0.89–2.05; Gln/Gln versus Arg/Gln + Arg/Arg: OR = 1.37, 95% CI = 0.93–2.02). This meta-analysis supported that IL-13 SNP rs20541 was associated with AR, particularly in Asians.

Two-stage split-injection strategies for partially premixed compression ignition (PPCI) combustion mode were investigated in a light duty 2.2 L four cylinder compression ignition engine fuelled with G50-Dieseline (50% ULG95 gasoline in EN590 diesel by volume). The investigation of two-stage split-injection has been focused on injection quantity-ratios and timings and it aims to achieve improved charge premixing and consequently reduce the oxides of nitrogen (NO x ) and particulate matter (PM) emissions simultaneously. Other parameters affecting combustion process (e.g. compression ratio) were fixed to identify the individual effects of parameters under study on the combustion and emission characteristics by the Taguchi-DOE (design of experiment) analysis. The investigation was conducted for two load groups of 1.37 and 2.97 bar BMEP selected from the new European driving cycle (NEDC) at an engine speed of 1800 RPM. Optimum operating values of injection parameters for generating the minimum and maximum combustion and emission characteristics were identified. Furthermore, very early first injection-timings were investigated for 2.97 bar BMEP with the combustion phase of 50% accumulative heat release (AHR-50) fixed. Compared with the single-injection strategy, BSNO x was reduced by approximately 39% to 59% through applying the two-stage split-injection. Accumulation particulate concentration as well as smoke number were reduced by approximately 90%. It is believed that with very early first-injection timings, fuel wall-impingement and over mixing may have resulted in lower combustion efficiency and thus BMEP drop. Consequently, the premixing process can reach a limit where the effect of required higher injected fuel quantity dominates combustion and emission characteristics. The two-stage split-injection developed in this study appears to be effective in improving the premixing process for PPCI combustion.

To meet the needs of fuel security and combat the growing concerns of CO2 emissions, the automotive industry is seeking solutions through biofuels. Traditionally, when supplying biofuel blends to the combustion chamber, the blend is mixed externally prior to its injection in one location. This location occurs either before the cylinder (port-fuel injection, PFI), or directly into the cylinder (direct-injection, DI). However, the use of dual-injection allows the in-cylinder blending of two fuels at any blend ratio, when combining the two locations (PFI and DI). This injection strategy offers increased flexibility as the blend ratio can be changed instantaneously according to engine speed and load demand and fuel availability. Previous work by the authors has reported the improved combustion performance of dual-injection with 25% blends (in gasoline) of a new biofuel candidate: 2,5-dimethylfuran (DMF). This current investigation extends the analysis to include the gaseous emissions of various DMF blends (25%, 50% and 75%) from 3.5 bar to 8.5 bar IMEP and the particulate matter (PM) emissions of similar fraction ethanol blends at a selected condition of 5.5 bar IMEP. Compared to DI, dual-injection offers reduced CO and CO2 emissions and comparable HC emissions. The mean PM diameter is decreased and the accumulation mode particles are negligible compared to DI. However, the implication of the higher combustion pressures is an increase in NOx due to reduced charge-cooling.

Straight-run naphtha is tested in the newly raised combustion concept, called multiple premixed compression ignition (MPCI) mode, on a single cylinder diesel engine under different speeds. The partially premixed compression ignition (PPCI) mode is also investigated for comparison. The MPCI mode proposed by the authors was realized by multiple premixed combustion processes in a sequence of “spray–combustion–spray–combustion” around the compression top dead center (TDC). The spray and combustion events are preferred to be separated completely, with a dominant feature of “Combust After Injection End, Inject After Combustion End” to ensure the multiple-stage premixed compression ignition. The PPCI mode is well known as the “spray–spray–combustion” sequence with the start of combustion (SOC) separated from the end of injection (EOI). The straight-run naphtha has a research octane number (RON) of 58.8, and the compression ratio and displacement of the test engine is 16.7 and 0.5L. Double injection strategy is employed to generate the PPCI and MPCI modes. Maximum pressure rise rate and NOx emission of the MPCI mode is lower than that of PPCI mode, and it is easier to produce MPCI mode at lower engine speed. Diesel is also tested under double injection strategy just as the PPCI mode, but the fuel efficiency and emission performance is worse than that of straight-run naphtha.