Ritchie Daniel

Effects of Combustion Phasing, Injection Timing, Relative Air-Fuel Ratio and Variable Valve Timing on SI Engine Performance and Emissions using 2,5-Dimethylfuran

Ethanol has long been regarded as the optimal gasoline-alternative biofuel for spark-ignition (SI) engines. It is used widely in Latin and North America and is increasingly accepted as an attractive option across Europe. Nevertheless, its low energy density requires a high rate of manufacture; in areas which are deficient of arable land, such rates might prove problematic. Therefore, fuels with higher calorific values, such as butanol or 2,5-dimethylfuran (DMF) deserve consideration; a similar yield to ethanol, in theory, would require much less land. This report addresses the suitability of DMF, to meet the needs as a biofuel substitute for gasoline in SI engines, using ethanol as the biofuel benchmark. Specific attention is given to the sensitivity of DMF to various engine control parameters: combustion phasing (ignition timing), injection timing, relative air-fuel ratio and valve timing (intake and exhaust). Focus is given to the window for optimization; the parameter range which sustains optimal IMEP (within 2%) but provides the largest reduction of emissions (HC or NOx). The test results using a single cylinder SI research engine at 1500rpm show how DMF is less sensitive to key engine parameters, compared to gasoline. This allows a wider window for emissions optimization because the IMEP remains optimal across a greater parameter range. Copyright

DMF - A New Biofuel Candidate

This book aspires to be a comprehensive summary of current biofuels issues and thereby contribute to the understanding of this important topic. Readers will find themes including biofuels development efforts, their implications for the food industry, current and future biofuels crops, the successful Brazilian ethanol program, insights of the first, second, third and fourth biofuel generations, advanced biofuel production techniques, related waste treatment, emissions and environmental impacts, water consumption, produced allergens and toxins. Additionally, the biofuel policy discussion is expected to be continuing in the foreseeable future and the reading of the biofuels features dealt with in this book, are recommended for anyone interested in understanding this diverse and developing theme.

Split-Injection Strategies under Full-Load Using DMF, A New Biofuel Candidate, Compared to Ethanol in a GDI Engine

It is well known that direct-injection (DI) is a technology enabler for stratified combustion in spark-ignition (SI) engines. At full-load or wide-open throttle (WOT), partial charge stratification can suppress knock, enabling greater spark advance and increased torque. Such split-injection or double-pulse injection strategies are employed when using gasoline in DI (GDI). However, as the use of biofuels is set to increase, is this mode still beneficial? In the current study, the authors attempt to answer this question using two gasoline-alternative biofuels: firstly, ethanol; the widely used gasoline-alternative biofuel and secondly, 2,5-dimethylfuran (DMF); the new biofuel candidate. These results have been benchmarked against gasoline in a single-cylinder, spray-guided DISI research engine at WOT (λ=1 and 1500rpm). Firstly, single-pulse start of injection (SOI) timing sweeps were conducted with each fuel to find the highest volumetric efficiency and IMEP. The resulting optimum SOI timing for gasoline was then used as the first injection (SOI1) with each fuel in the split-injection tests. In this instance, second SOI timing (SOI2) sweeps were made using two split-ratios (SOI1:SOI2 = 1:1 and 2:1). For the single-pulse SOI timing sweeps, the change in IMEP when using ethanol is symmetrical either side of the maximum. However, when using gasoline and DMF, the behavior is asymmetrical, with maximums later and earlier than with ethanol, respectively. For split-injection, the maximum IMEP increases when fuelled with the biofuels, whilst maintaining acceptable engine stability. This increase, however, is much more dependent on SOI2 timing than with gasoline, due to the deterioration of in-cylinder mixing and slower combustion. Copyright

Hydrocarbon and Aldehyde Emissions from Combustion of 2-Methylfuran

ABSTRACT An investigation of hydrocarbon (HC) and aldehyde emissions from the combustion of 2-methylfuran (MF) was conducted, with samples taken from the exhaust of a single cylinder direct-injection spark ignition (SI) research engine. This article validates the mechanism of MF combustion, and assesses its toxic emissions. Aldehyde emissions from MF were quantitatively measured using high performance liquid chromatography, and the results were compared with those of gasoline, 2,5-dimethylfuran (DMF), ethanol, methanol, and n-butanol. The detected aldehydes were mainly formaldehyde and acetaldehyde. Reaction pathway analyses of the combustion of MF and DMF were performed using a closed homogeneous constant volume reactor model in the Chemkin package. The formaldehyde emission was related to the side chain of MF. It was only half that of DMF and it was much lower than those of other fuels. The acetaldehyde emission from MF was also one of the lowest among all tested fuels. HCs from MF combustion were qualitatively investigated using gas chromatography mass spectrometry. The exhaust spectrum detected signals from propylene, benzene, toluene, ethyl benzene, xylenes, carbonyl compounds, and furan series derivatives (furan, DMF, and furfural).

The Application of Two Closely Coupled DPFs as the After-treatment System

In this study, the application of two closely coupled Diesel Particle Filters (DPFs), composed of an assistant DPF and a main standard honeycomb DPF, was investigated. A series of tests were carried out on a light-duty common-rail Euro 4 diesel engine and the emissions were measured and compared with those when a standard DOC+DPF system was used for the after-treatment. Replacing the DOC with an assisting DPF (ADPF) showed significant advantages in the reduction of particles, which had a direct impact in reducing the soot loading rate of the main DPF by up to 30%. Its oxidation characteristics not only showed equivalent exhaust-conversion efficiency, which concern the regulated gaseous emissions (CO and HC) under most engine conditions, but also continuously regenerated the soot it trapped. The impacts on the particle size and distributions were investigated, based on the new regulations on particle number limits; as well as the increased back pressure which is an unavoidable compromise. The overall performance of this DPF+DPF strategy showed great potential to be adopted in the future, Not only can this cope with tighter emissions regulations but it also has great cost benefits as main DPFs size and weight can be reduced. It also encourages more options for other cheaper materials as less soot is collected. Copyright