Slavery and the Revival of Anti-slavery Activism

This chapter sets out the volumes critical approach to the dominant discourse on modern slavery and its impulse to question the assumptions and the politics behind that discourse. It explores the limits of the modern slavery rhetoric for understanding the complicated logics of agency, freedom and belonging, and of past, present and future, for those who are constituted as slaves. Document type: Part of book or chapter of boo

Review of waste heat recovery mechanisms for internal combustion engines

The demand for more fuel efficient vehicles has been growing steadily and will only continue to increase given the volatility in the commodities market for petroleum resources. The internal combustion engine utilizes approximately one third of the chemical energy released during combustion. The remaining two-thirds are rejected from the engine via the cooling and exhaust systems. Significant improvements in fuel conversion efficiency are possible through the capture and conversion of these waste energy streams. Promising waste heat recovery techniques include turbocharging, turbo compounding, Rankine engine compounding, and thermoelectric generators. These techniques have shown increases in engine thermal efficiencies that range from 2% to 20%, depending on system design, quality of energy recovery, component efficiency, and implementation. The purpose of this paper is to provide a broad review of the advancements in the waste heat recovery methods; thermoelectric generators and Rankine cycles for electricity generation, which have occurred over the past 10 years as these two techniques have been at the forefront of current research for their untapped potential. The various mechanisms and techniques, including thermodynamic analysis, employed in the design of a waste heat recovery system are discussed. Copyright © 2010 by ASME

Review of waste heat recovery mechanisms for internal combustion engines

The demand for more fuel efficient vehicles has been growing steadily and will only continue to increase given the volatility in the commodities market for petroleum resources. The internal combustion (IC) engine utilizes approximately one third of the chemical energy released during combustion. The remaining two-thirds are rejected from the engine via the cooling and exhaust systems. Significant improvements in fuel conversion efficiency are possible through the capture and conversion of these waste energy streams. Promising waste heat recovery (WHR) techniques include turbocharging, turbo compounding, Rankine engine compounding, and thermoelectric (TE) generators. These techniques have shown increases in engine thermal efficiencies that range from 2% to 20%, depending on system design, quality of energy recovery, component efficiency, and implementation. The purpose of this paper is to provide a broad review of the advancements in the waste heat recovery methods; thermoelectric generators (TEG) and Rankine cycles for electricity generation, which have occurred over the past 10 yr as these two techniques have been at the forefront of current research for their untapped potential. The various mechanisms and techniques, including thermodynamic analysis, employed in the design of a waste heat recovery system are discussed. © 2014 by ASME

Nucleate boiling identification and utilization for improved internal combustion engine efficiency

Internal combustion engines continue to become more compact and require greater heat rejection capacity. This demands research in cooling technologies and investigation into the limitations of current forced convection based cooling methods. A promising solution is the cooling strategy optimized with nucleate boiling to help meet these efficiency and emission requirements. Nucleate boiling results in an increased heat transfer coefficient, potentially an order of magnitude greater than forced convection, thereby providing improved cooling of an engine. This allows reduced coolant flow rates, increased efficiency, and reduced engine warm-up time. A study was conducted to characterize nucleate boiling occurring in the cooling passages of an IC engine cylinder head in a computational as well as experimental domain. The simulation was conducted to understand the physics of boiling occurring in an engine cooling passage and provide support for a potential boiling detection method. The computational fluid dynamics (CFD) simulation was performed for a simplified, two dimensional domain that resembled an engine cooling passage. The simulation results were followed by investigations of a pressure-based detection technique which was proven to be an effective method to detect boiling. An experimental test rig was used which consisted of a single combustion chamber section from a 5.4L V8 cylinder head. Water was used as the coolant. Results demonstrate the phase change physics involved in the boiling in an engine cooling passage, pressure variations in the coolant, heat flux data associated with the onset of nucleate boiling, and a comparison with existing boiling curves for water. Results of the simulation and experimental setup indicated that the change in energy and accompanying increase in pressure values can be related to bubble dynamics and thus provides a potential method to accurately detect nucleate boiling occurrence in an engine cooling system. Copyright © 2010 by ASME

Assessing the effect of E22 fuel on two-stroke and four-stroke snowmobile performance and emissions

A limited amount of information exists on the effect of higher ethanol content fuel (greater than 10 vol%) for recreational vehicle engines. The possibility exists for misfueling of these vehicles, as ethanol content may increase at gas stations in the near future. Engine management systems in the recreational vehicle market are typically not equipped with feedback controls to adapt to the increased ethanol content. To address this concern and generate preliminary data related directly to the recreational industry, a study was conducted to evaluate the impact of E22 fuel on steady-state emissions and performance of two production snowmobiles. To fully analyze the impact of higher ethanol blends, cold-start, durability, and material compatibility tests should be performed, in conjunction with emissions and performance tests. While these additional tests were not performed as part of this study, there is a test program that is assessing all these factors on E15 fuel, which will be released in fall 2012. E0 fuel was used to establish baseline performance and emissions data. A 2009 four-stroke snowmobile with a 998cc, liquid-cooled, four-cylinder, intake port-fuel injected engine and a 2009 two-stroke snowmobile with a 599cc, liquid-cooled, two-cylinder, electronically controlled, crankcase-fuel injected engine were used for this study. Neither vehicle had any feedback air-fuel controls or after-treatment devices in the exhaust system. Power, fuel consumption, relevant engine temperatures, as well as, regulated exhaust emissions were recorded using the E P A 5-mode certification test cycle. The data showed no major impact on power output for either the four-stroke or two-stroke snowmobile. Brake specific fuel consumption varied with E22 as compared to E0. A reduction in CO emissions for both vehicles was observed for the E22 fuel. Both vehicles were factory calibrated rich of stoichiometric and hence, the addition of ethanol to the fuel effectively leaned out the air/fuel ratio and thus reduced the CO emissions. HC emissions were reduced for both the four-stroke and two-stroke engines, though certain test points of the two-stroke engine produced HC emissions that exceeded the analyzer measurement range (idle). Leaner operation reduced HC formation. Exhaust gas temperatures were observed to increase from 20°C - 50°C with E22 fuel, due to enleanment. Copyright © 2012 by ASME

Comparison of piston temperature measurement methods: Templugs versus wireless telemetry with thermocouples

The objective of this investigation was to compare the results of metallurgical temperature sensors and thermocouples when used to measure piston temperatures in a running engine. Type J thermocouples and a microwave wireless telemetry system were used to gather real time temperature data on the piston in the vicinity of each metallurgical sensor. Eight pairs of metallurgical temperature sensors were installed in the piston with a thermocouple junction in-between. The engine was ramped up to steady state quickly and then held for approximately 4h at 1800 rpm and 1980Nm before being quickly ramped back down in accordance with the metallurgical sensors\u27 recommended test cycle. During the test, continuous temperature data at each of the sensor locations were monitored and recorded using the telemetry system. After the test was complete, the metallurgical temperature sensors were removed and independently analyzed. The results indicate that readings from the metallurgical temperature sensors were similar to those of the embedded thermocouples for locations without large thermal gradients. However, when thermal gradients were present, the metallurgical sensor\u27s reading was influenced measurably. Copyright © 2013 by ASME

Combustion and emissions characterization of soy methyl ester biodiesel blends in an automotive turbocharged diesel engine

Recent increases in petroleum fuel costs, corporate average fuel economy (CAFE) regulations, and environmental concerns about CO2 emissions from petroleum based fuels have created an increased opportunity for diesel engines and non-petroleum renewable fuels such as biodiesel. Additionally, the Environmental Protection Agencies Tier II heavy duty and light duty emissions regulations require significant reductions in NOx and diesel particulate matter emissions for diesel engines. As a result, the diesel engine and aftertreatment system is a highly calibrated system that is sensitive to fuel characteristics. This study focuses on the impact of soy methyl ester biodiesel blends on combustion performance, NOx, and carbonaceous soot matter emissions. Tests were completed using a 1.9 L, turbocharged direct injection diesel engine using commercially available 15 ppm ultra low sulfur (ULS) diesel, a soy methyl ester B20 biodiesel blend (20 vol % B100 and 80 vol % ULS diesel), and a pure soy methyl ester biodiesel. Results show a reduction in NOx and carbonaceous soot matter emissions, and an increase in brake specific fuel consumption with the use of biodiesel. Further, traditional methodology assumes that diesel fuels with a high cetane number have a reduced ignition delay. However, results from this study show the cetane number is not the only parameter effecting ignition delay due to increased diffusion burn. © 2010 by ASME

Development of a Supercharged Octane Number and a Supercharged Octane Index

Gasoline knock resistance is characterized by the Research and Motor Octane Number (RON and MON), which are rated on the CFR octane rating engine at naturally aspirated conditions. However, modern automotive downsized boosted spark ignition (SI) engines generally operate at higher cylinder pressures and lower temperatures relative to the RON and MON tests. Using the naturally aspirated RON and MON ratings, the octane index (OI) characterizes the knock resistance of gasolines under boosted operation by linearly extrapolating into boosted beyond RON conditions via RON, MON, and a linear regression K factor. Using OI solely based on naturally aspirated RON and MON tests to extrapolate into boosted conditions can lead to significant errors in predicting boosted knock resistance between gasolines due to non-linear changes in autoignition and knocking characteristics with increasing pressure conditions. A new Supercharged Octane Number (SON) method was developed on the CFR engine at increased intake pressures, which improved the correlation to boosted knock-limited automotive SI engine data over RON for several surrogate fuels and gasolines, including five Co-Optima RON 98 fuels and an E10 regular grade gasoline. Furthermore, the conventional OI was extended to a newly introduced Supercharged Octane Index (OIS) based on SON and RON, which significantly improved the correlation to fuel knock resistance measurements from modern boosted SI engine knock-limited spark advance tests. This demonstrated the first proof of concept of a SON and OIS to better characterize a fuel\u27s knock resistance in modern boosted SI engines