Search

The vehicle active suspension has been widely used as it could effectively improve the vehicle ride comfort. To solve the issues of actuator uncertainty and time delay existing in the active suspension system, a multi-objective non-fragile [Formula: see text] control algorithm is proposed in this work. First, to effectively describe the vehicle suspension dynamics, a quarter-car suspension model is constructed first in this study. Second, aiming at improving the ride quality and guarantee the hard constraints of the suspension system, a multi-objective H2/ H∞ performance index is proposed. Subsequently, the issues of external disturbances, actuator uncertainty and delay are considered in the design process of the suspension controller. Then, a multi-objective non-fragile control algorithm is proposed based on an effective Lyapunov functional. The control gain can be obtained by solving a convex optimization problem in terms of linear matrix inequalities. Finally, numerical simulations are implemented on MATLAB/Simulink platform to show the robustness and superiority of the proposed controller. Experiments are implemented on a quarter-car test rig to validate the practical performance of the designed controller.

The electronically controlled semi-active air suspension systems have been widely used to improve the vehicle ride comfort and road holding performance by adjusting the damper stiffness. This work focuses on the design of a damping force controller to enhance the ride comfort, road holding and stability under the presence of unknown air spring pressure. Firstly, an improved skyhook suspension reference model is developed to generate the desired dynamic criteria (i.e. vehicle body acceleration, pitch and roll angles). Secondly, by employing the backstepping technique, a novel damping force controller is proposed to approach the desired dynamic criteria. Thirdly, a parameter estimation method is also designed to estimate the air spring pressure to obtain the air spring force. Comparative studies are carried out among passive suspension systems, and the semi-active air suspension systems with the proposed model reference damping force control, traditional backstepping control and existing sliding mode control. Numerical results show that a significant improvement of ride comfort can be observed with the semi-active air suspension system based on the proposed model reference backstepping controller.

This study aims to explore the impacts of the blending, fumigating, and combined fumigating+blending (F + B) methods, compared to the diesel method, on the engine combustion and cyclic variability ...

The lifetime and efficiency of diesel particulate filters (DPFs) strongly depend on the proper and periodic cleaning and servicing. Unfortunately, in some cases, inappropriate methods are applied to clean the DPFs, e.g., using air compressors without proper disposal procedures which can have negative impacts on human health, the environment, and DPF's efficiency. However, there is no information available about the properties of this kind of PM. This research is therefore presented to explore the physicochemical and toxicity properties of aged PM trapped in a DPF (using compressed air for PM sampling) employing STEM, SEM, EDS, Organic Carbon Analyzer, TGA/DSC, and Raman Spectrometer for investigating the physicochemical properties, and assays of cell viability, cellular reactive oxygen species (ROS), interleukin-6, and tumor necrosis factor-alpha (TNF-α) for investigating the toxicity properties. Also, analyses from fresh PM samples from the diesel vehicle at two engine speeds are presented. It is found that at a certain/fixed PM number/mass for all three samples tested, the PM from DPF compared with the fresh PM can have both positive (particularly having the lowest water-soluble total carbon ratio) and negative impacts on human health (particularly having the highest cell death rate of 13.4%, ROS, and TNF-α) and the environment.

According to the literature, there is in lack of a comprehensive study to compare the combustion, performance and emissions of a diesel engine using diesel, biodiesel and ethanol fuels (DBE) in the blended mode and fumigation mode under various engine speeds. This study was conducted to fill this knowledge gap by comparing the effect of blended, fumigation and combined fumigation + blended (F + B) modes on the combustion, performance and emissions of a diesel engine under a constant engine load (50% of full torque) with five engine speeds ranging from 1400 rpm to 2200 rpm. A constant overall fuel composition of 80% diesel, 5% biodiesel and 15% ethanol, by volume % (D80B5E15), was utilized to provide the same fuel for comparing the three fueling modes. According to the average results of five engine speeds, the blended mode has higher peak heat release rate (HRR), ignition delay (ID), brake thermal efficiency (BTE), brake specific nitrogen monoxide (BSNO) and brake specific nitrogen oxides (BSNOX), but lower duration of combustion (DOC), brake specific fuel consumption (BSFC), brake specific carbon dioxide (BSCO2), brake specific carbon monoxide (BSCO), brake specific hydrocarbon (BSHC), brake specific nitrogen dioxide (BSNO2), brake specific particulate matter (BSPM), total number concentration (TNC) and geometric mean diameter (GMD), and similar peak in-cylinder pressure compared to the fumigation mode. In addition, for almost all the parameters, results obtained in the F + B mode are in between those of the blended and fumigation modes. In regard to the effect of engine speed, the results reveal that the increase in engine speed causes reduction in peak in-cylinder pressure, BTE, BSHC, BSNOX, BSNO and BSNO2, but increase in peak HRR, ID, DOC, BSFC, BSCO2, BSPM and TNC, and similar BSCO and GMD for almost all the tested fueling modes. It can be inferred that the blended mode is the suitable fueling mode, compared with the fumigation mode, under the operating conditions investigated in this study.

This experimental study aims to investigate the effects of different fueling modes, including diesel, blended, fumigation and fumigation + blended (F + B) modes, on the chemical properties and composition of particulate matter (PM) of a diesel engine fueled with diesel-biodiesel-ethanol fuel (D80B5E15, volume %) under four operating conditions. It is found that the use of DBE has different effects on the chemical properties and composition of PM in the blended mode or the fumigation mode. The blended mode has higher organic carbon (OC)/total carbon (TC) ratio, but lower TC, OC, elemental carbon (EC), EC/TC ratio, water-soluble organic carbon, inorganic ions, metals and elements compared to those of the fumigation mode. For the PM composition, the diesel mode has the highest ratios of TC (85.8%), EC (47.6%) and inorganic ions (1.9%) and the lowest ratios of OC (38.2%), metals and elements (0.7%) and unknown species (11.6%). In contrast, the lowest ratios of TC (80.4%), EC (28.0%) and inorganic ions (1.6%) and the highest ratios of OC (52.4%) and unknown species (16.7%) are found for the blended mode. The highest metals and elements ratio (1.4%) is found in the fumigation mode. The F + B mode has the impacts between those of the fumigation and blended modes.

This experimental study was conducted to explore the favorable and unfavorable conditions which promote or reduce the performance and emissions in a diesel engine, based on six engine loads (5% to 95% load) and five biodiesel contents including B0 (0% waste cooking oil biodiesel and 100% diesel, by volume %), B20, B50, B75 and B100 (pure biodiesel), at a constant engine speed of 1920 rpm. According to the results, the maximum brake specific fuel consumption was recorded at the lowest engine load (5% load) using B100; while the highest brake thermal efficiency was obtained at 80% load for B100. In regard to regulated emissions, the highest engine load (95% load) with diesel fuel was the condition for the formation of maximum CO, smoke opacity, PM mass, total particle number concentration and geometric mean diameter. The 95% load with B100 was the condition for maximum CO2 and NOX. The 60% load with diesel fuel was the condition for maximum THC. For unregulated emissions, low engine load with B100 was the condition for maximum formaldehyde, acetaldehyde, ethene and propene. The maximum 1,3-butadiene was observed for B100 at 80% load. The highest benzene emission was recorded at 40% load for B100. The maximum toluene and xylene emissions were found at 5% load for diesel fuel. In addition, the conditions which lead to produce the minimum emissions are also extensively discussed in the present study.

Despite the improvement in technologies for the production of alternative fuels (AFs), and the needs for using more AFs for motor vehicles for the reductions in air pollution and greenhouse gases, the number of alternative fuel vehicles (AFVs) in the global transportation sector has not been increasing significantly (there are even small drops for adapting some AFs through the projections) in recent years and even in the near future with projections to 2050. And gasoline and diesel fuels will remain as the main energy sources for motor vehicles. After reviewing the latest advantages and disadvantages of AFVs, including flexible-fuel, gas, electric, hybrid electric, and fuel cell electric vehicles, it is found that the higher price of AFVs, compared to that of gasoline and diesel vehicles, might be one of the main barriers for their wider adoption. But on the other hand, there is the “chicken and egg” problem. Because people mostly do not select AFVs due to their higher price and sometimes their less infrastructure availability compared to those of gasoline and diesel vehicles, however, governments and AFVs manufacturers claim that the insignificant demand volume and less interest by people to purchase them, is one of the main reasons for a higher price and less infrastructure availability of AFVs. So, what should we do for adopting AFVs? This review shows that there are two very important and fundamental points that might cause a rise in the demand and usage of AFVs, rather than waiting for the reduction in AFVs prices. Those points are car salespeople's and people's knowledge about AFVs and the environmental issues, and their encouragement to accept and use AFVs. Although the AFVs are available on the market for many years, many people around the world have no/less/old/wrong knowledge about the current AFVs. Thus, most of these people reject these vehicles for usage, even when their important parameters such as purchase price, operating cost, driving range, and fuel availability be the same (or close) as those of gasoline or diesel vehicles. Detailed information, examples, and recommendations to the increases in people's knowledge and encouragement are presented in this review., Highlights • Latest advantages and drawbacks of alternative fuel vehicles (AFVs) are presented. • AFVs include flexible-fuel, gas, electric, hybrid, and fuel cell electric vehicles. • People's knowledge and encouragement on AFVs are important for wider AFVs adoption. • Several technical recommendations for increase in AFVs adoption rate are presented. • This review is useful for the researchers, governments, and policymakers on AFVs., Alternative fuel and vehicle policy; Alternative fuel vehicles; Clean fuels; Consumer purchase intention; Environmental concern; Gasoline and diesel vehicles.

The literature shows that information about the physical, chemical, and cell toxicity properties of particulate matter (PM) from diesel vehicles is not rich as the existence of a remarkable number of studies about the combustion, performance, and emissions of diesel vehicles using renewable liquid fuels, particularly biodiesels and alcohols. Also, the PM analyses from combustion of spent coffee ground biodiesel have not been comprehensively explored. Therefore, this research is presented. Pure diesel, 90% diesel + 10% biodiesel, and 90% diesel + 9% ethanol + 1% biodiesel, volume bases, were tested under a fast idle condition. STEM, SEM, EDS, Organic Carbon Analyzer, TGA/DSC, and Raman Spectrometer were employed for investigating the PM physical and chemical properties, and assays of cell viability, cellular reactive oxygen species, interleukin-6, and tumor necrosis factor-alpha were examined for investigating the PM cell toxicity properties. It is found that the application of both biodiesel and ethanol has the potential to change the PM properties, while the impact of ethanol is more than biodiesel on the changes. Regarding the important aspects, biodiesel can be effective for better human health (due to a decrease in cell death (-60.8%)) as well as good diesel particulate filter efficiency (due to lower activation energy (-7.6%) and frequency factor (-83.2%)). However, despite a higher impact of ethanol on the reductions in activation energy (-24.8%) and frequency factor (-99.0%), this fuel causes an increase in cell death (84.1%). Therefore, biodiesel can be an appropriate fuel to have a positive impact on human health, the environment, and emissions catalysts performance, simultaneously.

The present study aimed to compare the combustion, performance and emissions of a diesel engine fueled with diesel, biodiesel and ethanol in the blended and fumigation modes. In addition, a combined fumigation and blended mode (F + B) of fueling was introduced to understand its behavior in comparison with the blended and fumigation modes. In the blended mode, the fuel was composed of 80% diesel, 5% biodiesel and 15% ethanol (DBE), by volume. In the fumigation mode, a mixture of biodiesel and ethanol (BE) was injected into the intake manifold and diesel fuel was used as the main fuel. In the F + B mode, half of the BE mixture was injected into the intake manifold and another half of the DB mixture was mixed with diesel to form the main fuel. The experiments were conducted at a speed of 1800 rpm with five engine loads at a constant mixture percentage of D80B5E15 for the three fueling modes to provide the same fuel composition for comparing the effects of the three fueling modes. According to the average of five loads, compared to the pure diesel operation, the blended mode causes increases in peak heat release rate (HRR), ignition delay (ID), BSFC, CO, HC and NO2; drops in duration of combustion (DOC), CO2, NOX, PM, total number concentration (TNC) and geometric mean diameter (GMD); and similar peak in-cylinder pressure and BTE. While the fumigation mode leads to higher peak HRR, DOC, BSFC, CO, HC, NO2 and TNC; lower ID, BTE and NOX; and similar peak in-cylinder pressure, CO2, PM and GMD in comparison with the diesel mode. In addition, the F + B mode has the effects between those of the fumigation and blended modes. Among the three fueling modes, the blended mode gives the highest engine performance and lowest emissions, except for NOX. In contrast, the fumigation mode gives the worst engine performance and emissions, except for NOX.

Gasoline and diesel vehicles are one of the main sources of PMs generation which are harmful to human health and the environment. The light emitted from the headlights of these vehicles may cause to make the PMs more/less/not dangerous than the raw PMs to human health and the environment by changing their properties. However, there is no information available in this field. Therefore, this research is presented to investigate the effect of light emitted from one of the most common vehicle headlights (Halogen type) on the physical properties of PMs. Three PM samples taken directly from one diesel vehicle operating at an idle condition, and inside of a diesel particulate filter and gasoline vehicle exhaust pipe (engine was off) were exposed to the vehicle headlight for 6 hrs at 10 cm distance. It is observed that the vehicle light has the potential to change the structure, shape, and size of the PMs, while the fresh PMs from diesel vehicle receives more changes (43.5% increase in particle diameter) compared with the other two samples containing mature/aged PMs (increases of 3.6 and 9.9%, respectively). Also, the effect of the beam from the scanning electron microscope on the PM physical properties is presented.

This experimental study is conducted to investigate the combustion, performance and emissions of a diesel engine fueled with different alternative fuels under five engine loads and at an engine speed of 1800 rpm. Seven fuels, including diesel (D), waste cooking oil biodiesel (B), methanol (M), ethanol (E), 2-propanol (Pr), n-butanol (Bu) and n-pentanol (Pe)) were used to produce six blended fuels, labelled as DB, DBM, DBE, DBPr, DBBu and DBPe. Each blended fuel has the same oxygen content of 5.0% and very close carbon and hydrogen contents and LHV. According to the average results of five loads, the blended fuels in general cause to (a) increases in peak HRR (except DB), ignition delay (except DB), COVIMEP (except DBM), COV Max(dP/dθ) (except DB and DBM) and BSFC; (b) slight decrease in duration of combustion (except DB); and (c) similar peak in-cylinder pressure and BTE (except DBM and DBBu) compared to diesel fuel. Moreover, all the blended fuels lead to reductions in CO2 (except DB), CO, HC, NOX (except DB), PM, total number concentration (except DBPr) and geometric mean diameter, compared to diesel fuel. Overall, DBM shows the highest BTE, the lowest BSFC, and the lowest CO2, CO, HC, PM, NOX (after DBPr), COVIMEP and COV Max(dP/dθ) (after DB), while DB has the lowest influence, among all the tested blended fuels.

In recent years, the effect of alcohols as an alternative fuel on emissions of IC engines has been investigated in a lot of experimental works. However there is a lack of a comprehensive review study about the definition and type of emissions (regulated and unregulated emissions) and alcohols and the influence of alcohols on unregulated emissions of IC engines. Therefore, this literature review study is presented. In the current literature review work, two sections are provided. A brief detail of the effect of alcohols (methanol and ethanol) in blended and fumigation modes on regulated emissions in IC engines is presented in the first section. And the second section (main section of this work) is a comprehensive review part of the literatures related to the effect of methanol and ethanol in blended and fumigation modes on unregulated emissions in IC engines. In this literature review work, a wide type of IC engines, such as SI and CI engines and motorcycles were collected with different operation conditions. Different percentages of alcohol blend and fumigation were summarized to get informations about the effect of alcohol on regulated and unregulated emissions of IC engines. For regulated emissions, it was found that application of alcohols as alternative fuels in fumigation mode in IC engines led to reduction of NOX and CO2 in most tests and PM in all cases. However, an increase of CO and HC was observed with using alcohols in fumigation mode in most cases. It is noticeable that a diverse effect of alcohol application in blended mode compared to fumigation mode on regulated emissions was recorded in considerable tests except PM. For unregulated emissions, it was found a reduction of BTEX (benzene, toluene, ethylbenzene and o-xylene, m/p-xylenes) in blended mode in most cases, polycyclic aromatic hydrocarbons (PAHs) in blended mode in major experiments and 1,3-butadiene, ethyne and ethene in both modes in all tests with using alcohols compared to fossil fuels. On the other hand, it was seen an increase of unburned ethanol and methanol and total carbonyls in both modes in all tests. And, an increase of formaldehyde and acetaldehyde which are the predominant carbonyls in the exhaust for vehicles was recorded in most and major experiments, respectively for both modes. In addition, soluble organic fraction (SOF) had an increase in both modes in major tests. And an increase of benzene, toluene, xylene (BTX) was observed in fumigation mode in significant tests.

The present experimental study aims to examine the impacts of various fueling modes of operation on the particle-phase polycyclic aromatic hydrocarbons (PAHs) and n-alkanes (C16–C30), and volatility and oxidation reactivity of particulate matter (PM) emitted from a diesel engine fueled with a ternary fuel (80% diesel, 5% biodiesel and 15% ethanol (D80B5E15, volume %)) under four engine operating conditions. Four fueling modes, including diesel, blended, fumigation and combined fumigation + blended (F + B) modes were tested using pure diesel fuel for diesel mode and a constant fuel content of D80B5E15 for the blended, fumigation and F + B modes to create the same condition for comparing their impacts on the parameters investigated. The average results illustrate that both blended and fumigation modes can reduce the PAHs (−78.4% and −31.3%), benzo[a]pyrene equivalent (−81.7% and −38.9%), n-alkanes (−46.5% and −21.5%) and non-volatile substance fraction (−25.1% and −11.1%), but increase the high-volatile substance fraction (12.8% and 6.9%) and oxidation reactivity rate (34.0% and 4.9%), respectively compared to those of the diesel mode. While the effect of the blended mode on the parameters investigated is stronger than the fumigation mode. And the F + B mode has the effects in between the results of the blended and fumigation modes.

The present study aimed to explore the influences of different fueling modes, including diesel alone, blended, fumigation and a combined fumigation + blended (F + B) modes, on the particulate emission and physical properties of particulate matter (PM) emitted from a 4-cylinder diesel engine fueled with a ternary fuel (diesel-biodiesel-ethanol, DBE) under two engine speeds and loads. Biodiesel-ethanol (BE) fuel was mixed with diesel fuel in the blended mode; but it was sprayed into the intake air manifold in fumigation mode. In the F + B mode, half of the BE fuel was sprayed into the intake air manifold (same as fumigation mode); while another half of it was mixed with diesel to produce the DBE fuel (same as blended mode). The blended, fumigation and F + B modes had the same fuel composition (D80B5E15, volume %) for comparison of their impacts. According to the average results, the blended mode has lower PM mass, total number concentration (TNC) and geometric mean diameter (GMD) compared to the fumigation mode. In respect of the PM physical properties, the blended mode has lower primary particle size, fringe length, tortuosity and fringe separation distance compared to the fumigation mode. The magnitudes of all the parameters investigated in the F + B mode are in between those of the fumigation mode and the blended mode. Despite of using the same fuel of D80B5E15, the blended and fumigation modes show different effects on the PM emission; this finding shows that the effect of fueling type is stronger than fuel type. It can be summarized that the application of DBE in the blended mode has effect on reducing the PM emissions, especially PM mass (–42.5%), TNC (–22.3%) and GMD (–8.8%), while fumigation mode has almost no effect on the PM mass and GMD but causes increase in TNC (36.2%) compared to diesel mode.