Reductions in diesel emissions including PM and PN emissions with diesel-biodiesel blends

© 2017 Elsevier Ltd The current work is an experimental investigation to examine the influence of biodiesel derived from waste cooking oil on engine performance and exhaust emissions. Experiments were conducted with three biodiesel blends at 20%, 40%, and 60% (by volume). A petroleum diesel fuel was used as a reference fuel. The primary purpose of this study was to observe both particulate matter (PM) and particle number (PN) emissions for the three biodiesel blends. Furthermore, the blow-by emissions of the biodiesel blends were also studied. All measurements were conducted in a six-cylinder turbocharged diesel engine with a high-pressure common rail injection system in compliance with a 13-Mode European Stationary Cycle (ESC)

Engine performance during transient and steady-state operation with oxygenated fuels

© 2017 American Chemical Society. Owing to the increasing share of biofuels in combustion engines, use of these oxygenated fuels instead of diesel should be evaluated under different engine operating conditions. This paper studies the influence of oxygenated fuels on engine performance parameters under transient, compared to steady-state, operation on a six-cylinder, turbocharged, compression-ignition engine with a common rail injection system. The fuels used in this study were diesel, waste cooking biodiesel, and triacetin (as a highly oxygenated additive). A custom test was used to investigate different engine performance parameters during acceleration, load increase, and steady-state modes of operation. Additionally, a legislative transient cycle (NRTC), composed of many discrete transient modes, was used to study engine performance during a whole transient cycle. In this paper, different engine performance-related parameters were investigated, such as IMEP, BMEP, FMEP, turbocharger lag, air-to-fuel ratio, engine speed and torque, start of injection, start of combustion, injection pressure, maximum in-cylinder pressure, maximum rate of pressure rise, intake and exhaust manifold pressures, and CoV of IMEP. The investigation demonstrates that engine behavior during transient operation is different from steady-state operation. Results during NRTC indicated that, in comparison with diesel, the oxygenated fuels have lower IMEP (up to 18.7%), BMEP (up to 21.7%), and FMEP (up to 12.7%). During transient modes of the custom test, using oxygenated fuels rather than diesel resulted in higher indicated torque, maximum in-cylinder pressure, and maximum rate of pressure rise; however, during steady-state, most of the oxygenated fuels had lower values in these three parameters. Each advance in SOI corresponds to a rise in the maximum in-cylinder pressure and in the maximum rate of pressure rise. Oxygenated fuels had lower intake manifold pressure and CoV of IMEP than diesel. Different fuel properties were used to interpret engine behavior

Exergy analysis of a diesel engine with waste cooking biodiesel and triacetin

This study uses the first and second laws of thermodynamics to investigate the effect of oxygenated fuels on the quality and quantity of energy in a turbo-charged, common-rail six-cylinder diesel engine. This work was performed using a range of fuel oxygen content based on diesel, waste cooking biodiesel, and a triacetin. The experimental engine performance and emission data was collected at 12 engine operating modes. Energy and exergy parameters were calculated, and results showed that the use of oxygenated fuels can improve the thermal efficiency leading to lower exhaust energy loss. Waste cooking biodiesel (B100) exhibited the lowest exhaust loss fraction and highest thermal efficiency (up to 6% higher than diesel). Considering the exergy analysis, lower exhaust temperatures obtained with oxygenated fuels resulted in lower exhaust exergy loss (down to 80%) and higher exergetic efficiency (up to 10%). Since the investigated fuels were oxygenated, this study used the oxygen ratio (OR) instead of the equivalence ratio to provide a better understanding of the concept. The OR has increased with decreasing engine load and increasing engine speed. Increasing the OR decreased the fuel exergy, exhaust exergy and destruction efficiency. With the use of B100, there was a very high exergy destruction (up to 55%), which was seen to decrease with the addition of triacetin (down to 29%). © 2019 Elsevier Lt

A parametric study on engine performance and emissions with neat diesel and diesel-butanol blends in the 13-Mode European Stationary Cycle

© 2017 Elsevier Ltd This paper presents a comprehensive study of a wide range of engine performance parameters, including: indicated torque (IT), indicated power (IP), indicated mean effective pressure (IMEP) and indicated specific fuel consumption (ISFC). Further, the combustion parameters measured include: start of injection timing, in-cylinder peak pressure, boost pressure and rate of maximum pressure rise. Resultant emission parameters investigated include: exhaust blow by, unburned hydrocarbon (UBHC), oxides of nitrogen (NOx), particulate matter (PM), particle number (PN) and particle size distribution (PSD). Normal butanol (n-butanol) was chosen to blend with a reference diesel fuel. The experiment was conducted using a 6-cylinder, turbocharged common rail diesel engine in accordance with the 13-Mode European Stationary Cycle (ESC). Considering limits of solubility of n-butanol in reference diesel, a maximum of 30% n-butanol was blended with 70% reference diesel. Three different butanol blends having 10% butanol with 90% reference diesel, 20% butanol with 80% reference diesel and 30% butanol with 70% reference diesel (the blending percentages were on a volume basis) were prepared. The engine experimental results show that without considerably deteriorating engine performance, most of the emissions were significantly reduced with the butanol blends compared to those of the reference diesel

The influence of oxygenated fuels on transient and steady-state engine emissions

This research studies the influence of oxygenated fuels on transient and steady-state engine performance and emissions using a fully instrumented, 6-cylinder, common rail turbocharged compression ignition engine. Beside diesel, the other tested fuels were based on waste cooking biodiesel (primary fuel) with triacetin (highly oxygenated additive). A custom test was designed for this study to investigate the engine performance and emissions during steady-state, load acceptance and acceleration operation modes. Furthermore, to study the engine performance and emissions during a whole transient cycle, a legislative cycle (NRTC), which contains numerous discrete transient modes, was utilised. In this paper, the turbocharger lag, engine power, NOx, PM, PN and PN size distribution were investigated. During NRTC the brake power, PM and PN decreased with fuel oxygen content. During steady-state operation, compared to diesel, the oxygenated fuels showed lower indicated power, while they showed higher values during acceleration and turbocharger lag. During acceleration and load increase modes, NOx, PM and PN peaked over the steady-state counterpart, also, the accumulation mode count median diameter moved toward the larger particle sizes. Increasing the fuel oxygen content increased the indicated specific NOx and PN maximum overshoot, while engine power, PM, PN and PM maximum overshoot decreased. Also, the accumulation mode count median diameter moved toward the smaller particle sizes. © 2017 Elsevier Lt

The effect of triacetin as a fuel additive to waste cooking biodiesel on engine performance and exhaust emissions

This study investigates the effect of oxygenated fuels on engine performance and exhaust emission under a custom cycle using a fully instrumented 6-cylinder turbocharged diesel engine with a common rail injection system. A range of oxygenated fuels based on waste cooking biodiesel with triacetin as an oxygenated additive were studied. The oxygen ratio was used instead of the equivalence ratio, or air to fuel ratio, to better explain the phenomena observed during combustion. It was found that the increased oxygen ratio was associated with an increase in the friction mean effective pressure, brake specific fuel consumption, CO, HC and PN. On the other hand, mechanical efficiency, brake thermal efficiency, CO , NOx and PM decreased with oxygen ratio. Increasing the oxygen content of the fuel was associated with a decrease in indicated power, brake power, indicated mean effective pressure, brake mean effective pressure, friction power, blow-by, CO , CO (at higher loads), HC, PM and PN. On the other hand, the brake specific fuel consumption, brake thermal efficiency and NOx increased by using the oxygenated fuels. Also, by increasing the oxygen content, the accumulation mode count median diameter moved toward the smaller particle sizes. In addition to the oxygen content of fuel, the other physical and chemical properties of the fuels were used to interpret the behavior of the engine. 2

Influence of fuel-borne oxygen on European Stationary Cycle: Diesel engine performance and emissions with a special emphasis on particulate and NO emissions

Exploration of sustainable fuels and their influence on reductions in diesel emissions are nowadays a challenge for the engine and fuel researchers. This study investigates the role of fuel-borne oxygen on engine performance and exhaust emissions with a special emphasis on diesel particulate and nitric oxide (NO) emissions. A number of oxygenated-blends were prepared with waste cooking biodiesel as a base oxygenated fuel. Triacetin, a derivative from transesterified biodiesel was chosen for its high oxygen content and superior fuel properties. The experimental campaign was conducted with a 6-cylinder, common rail turbocharged diesel engine equipped with highly precise instruments for nano and other size particles and other emissions. All experiments were performed in accordance with European Stationary Cycle (ESC 13-mode). A commercial diesel was chosen as a reference fuel with 0% oxygen and five other oxygenated blends having a range of 6.02–14.2% oxygen were prepared. The experimental results revealed that the oxygenated blends having higher a percentage of fuel-borne oxygen reduced particulate matter (PM), particle number (PN), unburned hydrocarbon (UBHC) and carbon monoxide (CO) emissions to a significantly low level with a slight penalty of NO emissions. The main target of this study was to effectively utilise triacetin as an additive for waste cooking biodiesel and suppress emissions without deteriorating engine performance. The key finding of this investigation is the significant reductions in both particle mass and number emissions simultaneously without worsening engine performance with triacetin-biodiesel blends. Reductions in both particle mass and number emissions with a cost-effective additive would be a new dimension for the fuel and engine researchers to effectively use triacetin as an emission suppressor in the future

Engine blow-by with oxygenated fuels: A comparative study into cold and hot start operation

© 2017 Elsevier Ltd T{(NPI), 1999 #117}his research compares the effects of oxygenated fuels on engine blow-by during engine cold and hot start operation using a common rail, turbocharged diesel engine. Diesel, waste cooking biodiesel and a highly oxygenated additive, triacetin, were used to make a range of fuel oxygen contents (0–13.57%). This study investigated engine blow-by and its correlation with indicated, brake and friction power; and blow-by normalised by different parameters. Result showed that neat diesel produces higher blow-by during cold start than the oxygenated fuels. There was a strong correlation between blow-by and indicated power, and the fuel calorific value was identified as a leading factor. To further analyse the results, this study normalised the engine blow-by by power to reveal the other influences on engine blow-by. The result verified the strong influence of power. This study also furthered the analysis by normalising the blow-by data by exhaust flow rate, intake air flow rate and injected fuel flow rate. It was discovered that oxygenated fuels perform better between hot and cold start, when compared to diesel. The blow-by inhibited properties of oxygenated fuels, such as higher lubricity and viscosity may be the cause for better performance of oxygenated fuels during cold start

Influence of oxygen content of the certain types of biodiesels on particulate oxidative potential

Oxidative potential (OP) is related to the organic phase, specifically to its oxygenated organic fraction (OOA). Furthermore, the oxygen content of fuel molecules has significant influence on particulate OP. Thus, this study aimed to explore the actual dependency of the OOA and ROS to the oxygen content of the fuel. In order to reach the goal, different biodiesels blends, with various ranges of oxygen content; have been employed. The compact time of flight aerosol mass spectrometer (c-ToF AMS) enabled better identification of OOA. ROS monitored by using two assays: DTT and BPEA-nit. Despite emitting lower mass, both assays agreed that oxygen content of a biodiesel is directly correlated with its OOA, and highly related to its OP. Hence, the more oxygen included in the considered biodiesels, the higher the OP of PM emissions. This highlights the importance of taking oxygen content into account while assessing emissions from new fuel types, which is relevant from a health effects standpoint

Diesel engine emissions with oxygenated fuels: A comparative study into cold-start and hot-start operation

© 2017 Elsevier Ltd As biofuels are increasingly represented in the fuel market, the use of these oxygenated fuels should be evaluated under various engine operating conditions, such as cold-start. However, to-date quantification has been mostly done under hot-start engine operation. By using a custom test designed for this study, a comparative investigation was performed on exhaust emissions during cold- and hot-start with diesel and three oxygenated fuels based on waste cooking biodiesel and triacetin. This study used a six-cylinder, turbocharged, after-cooled diesel engine with a common rail injection system. The results during cold-start with diesel showed lower NOx (up to 15.4%), PN (up to 48%), PM1(up to 44%) and PM2.5(up to 63%). However, the oxygenated fuels during cold-start showed a significant increase in NOx (up to 94%), PN (up to 27 times), PM1(up to 7.3 times) and PM2.5(up to 5 times) relative to hot-start. The use of oxygenated fuels instead of diesel during hot-start decreased the PN, PM2.5and PM1(up to 91%) while, during cold-start, it only decreased PM1and PM2.5at some engine operating modes and increased PN significantly up to 17 times. In both cold- and hot-start, the use of oxygenated fuels resulted in an increase in NOx emission. For cold-start this was up to 125%, for hot-start it was up to 13.9%. In comparison with hot-start, the use of oxygenated fuels during cold-start increased nucleation mode particles significantly, which are harmful. This should be taken into consideration, since cold-start operation is an inevitable part of the daily driving schedule for a significantly high portion of vehicles, especially in cities