Combustion and Emissions of a Gas-to-Liquid Diesel Engine Utilizing Optimized Spiral-Helical Intake Manifold Designs

Abstract

Two simultaneous strategies were used to reduce diesel engine emissions. Optimized manifold designs were used with GTL fuel and its blend with diesel fuel. Six new spiral-helical manifolds were tested, which could be divided into two groups. The first group is with the same inner diameter (2.6 cm) and outlet angle (30°), but different number of spiral turns (1t, 2t..etc). The second group is with different inner diameters. The results showed that the highest pressure and heat release were achieved by m(2.6,30,1t) with the diesel-GTL blend. In addition, the heat release rate decreases with the increase in number of turns. The same combination also reduced the pressure raise rate (dP/dϑ) by about 24% compared to the normal manifold. For the emissions, the maximum reduction in CO emissions was achieved by using m(2.6,30,3t) and GTL with about 34%. In addition, the maximum HC reduction was achieved by m(2.1,30,3t) and GTL, which is about 99% lower than that of the normal manifold. NO emissions were reduced by about 25% when m(2.6,30,4t) and GTL are used. The total particulate matters (PM) were the lowest for m(2.6,30,1t) and normal manifold in case of diesel. Generally, It was found that the combination of m(2.6,30,1t) with GTL and its blend gave the optimum performance and low emissions among all manifolds.

An experimental and numerical investigation of the effects of the diaphragm pressure ratio and its position on a heated shock tube performance

“…A variety of recent studies were conducted involved using shock tubes along with high‐density fuel/air mixtures to obtain combustion features of conventional and alternative fuels at conditions relevant to those used in internal combustion engines and gas turbine machines 5‐8 . Ignition delay time (IDT), particularly in internal combustion engines, is a vital combustion characteristic that directly affects engine efficiency and exhaust emissions 9‐13 . This property in ICE can be defined as the time required to detect heat release once the air–fuel mixture reaches the self‐ignition (autoignition) temperature and pressure or the time interval between the start of ignition (raising injector needle) and the beginning of combustion 14 .…”

“…[5][6][7][8] Ignition delay time (IDT), particularly in internal combustion engines, is a vital combustion characteristic that directly affects engine efficiency and exhaust emissions. [9][10][11][12][13] This property in ICE can be defined as the time required to detect heat release once the air-fuel mixture reaches the self-ignition (autoignition) temperature and pressure or the time interval between the start of ignition (raising injector needle) and the beginning of combustion. 14 The total delay period is due to a combination of physical and chemical delays.…”