• Energy Research

In this study, the biodiesel obtained from the waste olive oil by transesterification method has been mixed with a 30% of diesel fuel as volume and tested with a single cylinder direct injection diesel engine. The main purpose of this study is to obtain purer biodiesel from waste olive oil using methyl alcohol (CH3OH) and sodium hydroxide (NaOH) as catalyst in the transesterification method and research performance, combustion and emission characteristics in detail in a direct injection diesel engine. The combustion, engine performance and exhaust emission values have been also compared with diesel fuel. The test engine was operated at a constant speed of 2200 rpm and different engine loads such as 3.25 Nm, 7.5 Nm, 11.25 Nm, 18.75 Nm. According to the experimental results, the thermal efficiency of biodiesel is lower by about 1% to 5% than diesel. CO is lower about 37.5 % with biodiesel than that of diesel at 18.75 Nm. CO2 is higher 41% with biodiesel than diesel at 11.25 Nm. NOx was measured 9.5% higher than diesel fuel at 18.75 Nm. Soot emissions decreased by 37.5% compared to diesel.

Abstract Alcohol based fuels attract the attention of alternative fuel researchers. Many studies have been performed about combustion, performance and emission characteristics of alcohol used in internal combustion engines. Fusel oil is an alcohol based fuel obtained as a by-product during alcohol fermentation. Up to the present there has been no study regarding the combustion characteristics of fusel oil in a spark ignition engine. In this experimental study, performance, emission and combustion characteristics of fusel oil were examined in a spark ignition engine at 2500 rpm and four different engine loads. In-cylinder pressures, heat release rates, flame development and flame propagation durations, crank angles corresponding 50% of total mass fraction burnt, engine torque, brake specific fuel consumptions, CO, HC and NO x emissions were investigated. The water content and lower heating value of the fusel oil aggravated the combustion. Flame development and flame propagation durations were prolonged. As a result engine performance dropped. In addition, fusel oil usage increased CO and HC emissions up to 21% and 25% respectively. NO x emissions decreased about 31% due to worse combustion performance of fusel oil.

Abstract In this study effects of compression ratio on HCCI combustion, performance and emissions was investigated parametrically. In addition to parametric investigation and as a novel way of the paper engine BSFC maps were obtained for RON20 andRON40 fuels and each compression ratios of 9:1, 10:1, 11:1 and 12:1. The parametric experiments were carried out at 800 rpm engine speed. In both parametric and mapping experiments were conducted at intake temperature of 353 K. In-cylinder pressure, ROHR, combustion duration, start of combustion, indicated mean effective pressure, thermal efficiency and CO, HC and NOx emissions were examined. It was determined that in-cylinder pressure and rate of heat release decreased while the mixture getting leaner. The increase of octane number of fuel led to extension of combustion duration. On the contrary, combustion duration decreased along with the increase of compression ratio. It was found that the CO and HC emission were high while NOx emissions were low at lower CR. With the increase of CR, CO and HC emissions decreased however NOx emissions increased. The maximum thermal efficiency was obtained as 38.2% at 800 rpm and 12:1 CR with RON40 fuel. The widest operational region was obtained with RON20 fuel at CR of 10:1 with a minimum BSFC value of 210 g/kWh.

In this numerical study, the effects of the premixed ratio, intake manifold pressure and intake air temperature on a four-cylinder, four-stroke, direct injection, low-compression-ratio gasoline engine, operated in reactivity-controlled compression ignition (RCCI) combustion mode at a constant engine speed of 1000 rpm, were investigated using Converge CFD software. The results of numerical analyses showed that the maximum in-cylinder pressure and heat release rate (HRR) increased and the combustion phase advanced depending on the rise in both intake manifold pressure and intake air temperature. The CA50 shifted by 18.5 °CA with an increment in the intake air temperature from 60 °C to 100 °C. It was observed that the combustion duration dropped from 44 °CA to 38 °CA upon boosting the intake manifold pressure from 103 kPa to 140 kPa. Moreover, a delay in the combustion phase occurred at a constant intake air temperature with an increasing premixed ratio. The maximum value of in-cylinder pressure was recorded as 36.15 bar (at 11 °CA aTDC) with the use of PRF20. Additionally, as the content of iso-octane in the fuel mixture was increased, combustion delay occurred, and the maximum value of in-cylinder temperature obtained was 11 °CA aTDC using PRF20 fuel at the earliest point. While HC and CO emissions reached the highest values at a 60 °C intake air temperature, NOx and soot emission values were detected at quite low levels at this temperature. The values of all these emissions increased with rising intake manifold pressure and reached their highest values at 140 kPa. In addition, while the highest HC and CO emission values were observed with the use of PRF60 fuel, the results revealed that the control of the combustion phase in the RCCI strategy is notably affected by the premixed ratio, intake manifold pressure and intake air temperature.

Additives are added to conventional fuels to ensure complete combustion of fuels, increase engine performance and reduce harmful emissions from vehicles. Hydrogen and oxygen-containing fuel additives added to fossil-based internal combustion engine fuels improve the properties of the fuels and reduce vehicle-related emissions. Evaluation of mixed fuels created by adding different types of alcohol and nano-sized additives to motor fuels as an alternative fuel in motor vehicles is among the most researched scientific studies recently. In this study, alcohol-gasoline fuels (E5, M5), NaBH4-alcohol-gasoline fuels (ES5, MS5), and pure gasoline were tested in a gasoline engine. Fuels used in engine tests; E5 fuel (5% by volume ethanol 95% gasoline blend), M5 fuel (5% by volume methanol 95% gasoline blend), ES5 fuel (5% by volume NaBH4-ethanol solution 95% gasoline blend), MS5 fuel (5% by volume NaBH4-methanol solution 95% gasoline mixture) and pure gasoline. In the experiments, brake thermal efficiency, engine torque, specific fuel consumption, and exhaust gas temperature were measured and compared with pure gasoline. Compared to gasoline, the exhaust gas temperatures of all blended fuels decreased. On the other hand, there was an increase in engine torque values, except for ES5 fuel. At the same time, there was an increase in both specific fuel consumption and brake thermal efficiency. When the CO and HC emission values of the blended fuels are compared with the gasoline fuel values, the highest reduction in CO emissions occurred in ES5 blended fuel with 65.53%, while the highest decrease in HC emission was realized in E5 fuel with 19.09%. On the other hand, when NOx and CO2 emissions of E5, M5, ES5, MS5 mixed fuels are compared with gasoline, NOx emissions are 12.63%, 28.37%, 19.65%, respectively; decreased by 36.03% but CO2 emissions increased by 8.51%, 30.46%, 34.48%, 25.95% respectively. © 2022 Elsevier Ltd