An artificial neural network approach to modelling absorbent asphalts acoustic properties

Sound-absorbing asphalts are particularly useful for reducing noise emissions from vehicular traffic. This solution is perfectly suited for urban areas, in fact the use of sound-absorbing asphalt represents a noise control measure with a negligible environmental impact. In the present work, the results of an experimental investigation on sound-absorbing asphalts were reported. First, the characteristics of the sound-absorbing asphalts used were experimentally found. Then, the measurements of the sound absorption coefficient of the asphalt specimens were investigated. In the final part, numerical simulation model with artificial neural networks of the acoustic coefficient were compared with the data obtained from the measurements. The neural network model showed good Pearson correlation coefficient values (0.894) which can be used with good accuracy to predict the sound absorption coefficient

Investigation on particulate emissions and combustion characteristics of a common-rail diesel engine fueled with Moringa oleifera biodiesel-diesel blends

In this study, a study of the effects of Moringa Oil Biodiesel (MOB) biodiesel-diesel blends on the engine's performance, exhaust particulate matter, gaseous emissions and combustion characteristics was carried out in a multi-cylinder high-pressure common-rail diesel engine. The experiment involved the use of baseline diesel and several MOB blends (MOB10, MOB20, MOB30 and MOB50) as the fuel for the diesel engine. The results concluded that the engine torques and brake power produced by all of the MOB blends is smaller to the baseline diesel. However, both the MOB blends and baseline diesel produced similar brake thermal efficiency (BTE). It is noticed that the brake specific fuel consumption (BSFC) of all MOB are indicating deterioration, but showing an improvement in the brake specific energy consumption (BSEC). Besides, the peak cylinder pressure and peak HRR indicated a trend of declination with the increasing biodiesel blend ratio. Furthermore, all MOB has shown a great improvement in the emission of carbon monoxide (CO), smoke and particulate matter (PM), except nitrogen oxides (NOx). In short, Moringa oil is suitable to use as a source of biodiesel fuel in the diesel engines without any engine modification needs to be done

Effect of two-stage injection dwell angle on engine combustion and performance characteristics of a common-rail diesel engine fueled with coconut oil methyl esters-diesel fuel blends

Diesel engine is widely used as prime mover due to its high thermal efficiency. Usage of renewable biodiesel in diesel engine is also widely studied due to its potential in reducing emission and as a replacement of conventional diesel. Biodiesel performance could be improved by blending it with petroleum diesel besides introducing appropriate injection strategies. In this experiment, the effect of percentage of biodiesel blends and injection strategies such as variations in start of injection (SOI) timing and dwell angle on diesel engine performance were investigated. The test engine used is four-stroke turbocharged direct injection diesel engine. Results show that exhaust emissions, engine performance and combustion characteristics are substantially affected by biodiesel blending ratio and SOI timing but slightly influenced by two-stage injection dwell angle. Biodiesel blends percentage could be raised to improve NOx and smoke emissions. Even though SOI performed at a later timing could reduce NOx emission, smoke emission increased. Dwell angle between two successive injections could be prolonged to lower the effect of the increase in smoke emission. It could also be inferred that by setting a proper SOI timing and dwell angle under two-stage injection scheme when suitable biodiesel blend is used, the engine performance could be optimized

Production, characterization, engine performance and emission characteristics of Croton megalocarpus and Ceiba pentandra complementary blends in a single-cylinder diesel engine

Compounding energy demand and environmental issues necessitate suitable alternative or partial replacement of fossil fuels. Among the possible sources, biodiesel from non-edible vegetable oil sources is more economically feasible and possesses characteristics close to those of petroleum diesel. Two potential non-edible biodiesel feedstocks "Croton megalocarpus" and "Ceiba pentandra" were used for biodiesel production through esterification and transesterification process on a laboratory scale. Biodiesel characterization, engine performance and emission characteristics were investigated in an unmodified direct injection, naturally aspirated, single-cylinder diesel engine. 20% (v/v) of each of C. megalocarpus (CM), C. pentandra (CP) and their combined blends (CMB20, CPB20, CMB15CPB05, CMB10CPB10, and CMB05CPB15) were tested under varying engine speeds ranging from 1000 rpm to 2400 rpm at full load conditions. CMB20 and CPB20 reduced the brake power (BP) by 2.63% and 3.70%, brake thermal efficiency (BTE) by 5.97% and 3.72%, carbon monoxide (CO) emission by 1.09% and 2.39%, hydrocarbon (HC) emission by 1.48% and 4.62% and smoke emission by 12.35% and 17.13%, respectively compared to petroleum diesel. On the other hand, CMB20 and CPB20 increased the brake specific fuel consumption (BSFC) by 9.74% and 7.63%, NOX emission by 13.19% and 15.45%, respectively. A mixture of 10% of both biodiesels with diesels (CMB10CPB10) provides better performance and emission characteristics. CMB10CPB10 reduced BP, BTE, CO, HC and smoke by 0.53%, 0.50%, 5.21%, 8.38% and 20.71%, respectively and increased BSFC and NOX by 3.90% and 18.66%, respectively compared to conventional diesel. A combined blend of CM and CP could be a sustainable substitute for fossil diesel in the context of performance and emission

Study of the oxidation stability and exhaust emission analysis of Moringa olifera biodiesel in a multi-cylinder diesel engine with aromatic amine antioxidants

In this study, the two most effective aromatic amine antioxidants N,N'-diphenyl-1,4-phenylenediamine (DPPD) and N-phenyl-1,4-phenylenediamine (NPPD), were used at a concentration of 2000 ppm. The impact of antioxidants on the oxidation stability, exhaust emission and engine performance of a multi-cylinder diesel engine fuelled with MB20 (20% Moringa oil methyl ester and 80% diesel fuel blend) were analysed at varying speed conditions at an interval of 500 rpm and a constant load. It was observed that, blending with diesel enhanced the oxidation stability of the moringa biodiesel by approximately 6.97 h, and the addition of DPPD and NPPD to MB20 increased the oxidation stability up to 34.5 and 18.4 h, respectively. The results also showed that the DPPD- and NPPD-treated blends reduced the NOx emission by 7.4% and 3.04%, respectively, compared to the untreated blend. However, they do have higher carbon monoxide (CO) and hydrocarbon (HC) levels and smoke opacities, but it should be noted that these emissions are still well below the diesel fuel emission level. The results show that the addition of antioxidant with MB20 also improves the engine's performance characteristics. Based on this study, MB20 blends with amine antioxidants can be used in diesel engines without any modification

Optimization of performance, emission, friction and wear characteristics of palm and Calophyllum inophyllum biodiesel blends

A running automobile engine produces more friction and wear between its sliding components than an idle one, and thus requires lubrication to reduce this frictional effect. Biodiesel is an alternative diesel fuel that is produced from renewable resources. Energy studies conducted over the last two decades focused on solutions to problems of rising fossil fuel price, increasing dependency on foreign energy sources, and worsening environmental concerns. Palm oil biodiesel is mostly used in Malaysia. This study conducted engine performance and emission tests with a single-cylinder diesel engine fueled with palm and Calophyllum inophyllum biodiesel blends (PB10, PB20, PB30, CIB10, CIB20, and CIB30) at a full-load engine speed range of 1000-2400 rpm, and then compared the results with those of diesel fuel. Friction and wear tests were conducted using the four-ball tester with different temperatures at 40 and 80 kg load conditions and a constant speed of 1800 rpm. The average brake specific fuel consumption increased from 7.96% to 10.15% while operating on 10%, 20%, and 30% blends of palm and C. inophyllum biodiesel. The respective average brake powers for PB20 and PB30 were 9.31% and 12.93% lower compared with that for diesel fuel. PB20 produced relatively lower CO and HC emissions than the diesel and biodiesel blends. Diesel produced low amounts of NOX emission, and the CIB blend produced a lower frictional coefficient compared with the diesel and PB blends. PB30 showed high average FTP and low average WSD, both of which enhanced lubricating performance. An average metal element composition was found in PB20 under the 40 and 80 kg load conditions. PB20 showed lower worn scar surface areas compared with the diesel and biodiesel blends. Results indicated that PB20 has better engine performance, lower emission, and good lubrication properties compared with diesel and biodiesel blends. Thus, PB20 is suitable for use in diesel engines without the need for any engine modification

Impact of two-stage injection fuel quantity on engine-out responses of a common-rail diesel engine fueled with coconut oil methyl esters-diesel fuel blends

Two-stage injection with different biodiesel percentage is investigated where first and second injections were implemented with different SOI timings at various mass ratio under constant speed of 2000 rpm and 60 Nm of torque. The results reveal that maximum BTE of 32.4% and minimum BSFC of 245.5 g/kWh can be achieved simultaneously with injection mass ratio of 50:50 at advanced SOI timing using baseline diesel. A considerably lower level of NOx below 90 ppm is achievable via late SOI timing by using B20 or B50 biodiesel blends with injection mass ratio of 25:75. Specifically, the lowest NOx of 82 ppm can be achieved with smoke emission level still remains below 5% when B50 biodiesel blend and 25:75 injection mass ratio is tested. The highest reduction of 5.3% of smoke compared to diesel was achieved when B50 was used with 50:50 mass ratio at retarded SOI of 2°ATDC. It was found that simultaneous NOx and smoke reduction compared to that of fossil diesel is feasible with the application of B50 biodiesel blend and execution of retarded SOI timing and injection mass ratio of 25:75. Lastly, two-stage fuel injection is a practical strategy to simultaneously decrease NOx and smoke emissions

Study of the oxidation stability and exhaust emission analysis of Moringa olifera biodiesel in a multi-cylinder diesel engine with aromatic amine antioxidants

In this study, the two most effective aromatic amine antioxidants N,N'-diphenyl-1,4-phenylenediamine (DPPD) and N-phenyl-1,4-phenylenediamine (NPPD), were used at a concentration of 2000 ppm. The impact of antioxidants on the oxidation stability, exhaust emission and engine performance of a multi-cylinder diesel engine fuelled with MB20 (20% Moringa oil methyl ester and 80% diesel fuel blend) were analysed at varying speed conditions at an interval of 500 rpm and a constant load. It was observed that, blending with diesel enhanced the oxidation stability of the moringa biodiesel by approximately 6.97 h, and the addition of DPPD and NPPD to MB20 increased the oxidation stability up to 34.5 and 18.4 h, respectively. The results also showed that the DPPD- and NPPD-treated blends reduced the NOx emission by 7.4% and 3.04%, respectively, compared to the untreated blend. However, they do have higher carbon monoxide (CO) and hydrocarbon (HC) levels and smoke opacities, but it should be noted that these emissions are still well below the diesel fuel emission level. The results show that the addition of antioxidant with MB20 also improves the engine's performance characteristics. Based on this study, MB20 blends with amine antioxidants can be used in diesel engines without any modification

Development and characterization of sound-absorbing materials produced from agricultural wastes in Saudi Arabia

Green materials can be a valid alternative to traditional ones as they are produced and disposed without damaging the environment. In the present paper, materials developed from agricultural wastes from Saudi Arabia are presented. The natural materials considered are: date palm tree leaves, wheat straw fibres and eucalyptus, globules leaves. The values of the sound absorption coefficients of these biodegradable natural materials are reported. The sound absorption coefficients were measured with the impedance tube in the frequency range 200 Hz - 2,000 Hz. Sound absorption coefficients resulted greater than 0.5 at frequencies above 900 Hz for almost all the samples, which indicates good sound absorption behaviour. The paper concludes with some considerations about the potential use of these materials in room acoustics