Fuel efficiency analysis and peak pressure rise rate improvement for neat n-butanol injection strategies

Abstract

Engine tests were conducted to investigate the efficiency and the peak pressure rise rate performance of different fuel injection strategies for the direct injection of neat n-butanol in a compression ignition engine. Three different strategies were tested: a single-shot injection; a pilot injection; a post-injection. A single-shot injection timing sweep revealed that early injections had the highest indicated efficiency while late injections reduced the peak pressure rise rate at the cost of a slightly reduced thermal efficiency. Delayed single-shot injections also had increased emissions of nitrogen oxides, total hydrocarbon and carbon monoxide. Addition of a pilot injection had a negative effect on the peak pressure rise rate. Because of the low cetane number of butanol and the relatively lean and well-premixed air–fuel mixture, the pilot injection failed to autoignite and instead ignited simultaneously with the main injection. This resulted in slightly increased peak pressure rise rates and significantly increased unburned butanol hydrocarbon emissions. Conversely, the use of an early post-injection produced a noticeable engine power output and allowed the main injection to be shortened and the peak pressure rise rate to be substantially reduced. However, relatively early post-injections slightly reduced the indicated efficiency and increased the nitrogen oxide emissions and the carbon monoxide emissions compared with the single-shot injection strategy. These results recommended the use of a single-shot injection for low loads and medium loads owing to a superior thermal efficiency and suggested that the application of a post-injection may be more suited to high-load conditions because of the substantially reduced peak pressure rise rates.

Effect of Injection Pressure and Air–Fuel Ratio on the Self-Ignition Properties of 1-Butanol–Diesel Fuel Blends: Study Using a Constant-Volume Combustion Chamber

“…Other types of alternative fuels are alcohols. The studies on the use of these types of fuels and fuel blends in DEs focus on the use of ethanol, − methanol, − and 1-butanol. − Their use is associated with beneficial ecological effects, especially the limitation of pollutant emissions. ,,,,, …”

Experimental Study on the Effect of Injection Parameters On Combustion and Particulate Size Distribution of Partially Premixed Combustion Fueled with N-butanol

“…In the previous studies, n-butanol is typically served as blended fuel with gasoline or diesel in order to reduce the soot emission [4,[5][6][7][8][9]. In addition, n-butanol can also be adopted as a single alternative fuel [10][11][12][13][14]. It is indicated that the n-butanol PPC combustion has the potential to obtain low NOx and soot emissions, as well as high thermal efficiency.…”

Effects of split and single injection strategies on particle number emission and combustion of a GDI engine

“…On the whole, many engine workers have researched the influence of fuel injection parameters on the engine combustion and emission, [26][27][28][29] and a lot of deep and valuable results have been revealed. But there is relatively little research about the particle emission characteristics of GDI engines.…”