The effect of fuel composition and additive packages on deposit properties and homogeneous charge compression ignition combustion

Abstract

Homogeneous charge compression ignition combustion is highly dependent on in-cylinder thermal conditions that are favorable to auto-ignition, and the presence of deposits can dramatically impact the in-cylinder environment. Because fuels available at the pump can differ considerably in composition, and fuel composition and the included additive package directly affect how deposits accumulate in a homogeneous charge compression ignition engine, strategies intended to bring homogeneous charge compression ignition to market must account for this fuel and additive variability. In order to investigate this impact, two oxygenated refinery stream test fuels with two different additives were run in a single cylinder homogeneous charge compression ignition engine. The two fuels had varying chemical composition; one represents a “dirty” fuel with high aromatic content that was intended to simulate a worst-case scenario for deposit growth, while the other represents a California Reformulated Gasoline Blendstock for Oxygenate Blending fuel, which is the primary constituent of pump gasoline at fueling stations across the state of California. The additive packages are typical of technologies that are commercially available to treat engine deposits. Both fuels were run in an experimental, single-cylinder homogeneous charge compression ignition engine in a passive conditioning study, during which the engine was run at steady state over a period of time in order to track changes in the homogeneous charge compression ignition combustion event as deposits accumulated in-cylinder. Both the composition and the additive influenced the structure of the combustion chamber deposit layer, but more importantly, both the rate at which the layer developed and the equilibrium thickness it achieved. The overall thickness of the combustion chamber deposit layer was found to have a significant impact on homogeneous charge compression ignition combustion phasing.

Enabling robust simulation of polyoxymethylene dimethyl ether 3 (PODE3) combustion in engines

“…Validations in HCCI engines are considered more fundamental than other types of engines as the combustion is solely dependent on autoignition properties of fuels. [116][117][118] Figure 19 illustrates the comparison between the simulations results and HCCI experiment conducted by Wang et al 28 The experiment was carried out at an engine speed of 1600 rounds per minute (rpm) and an ER of 0.34, typical of a HCCI engine. Since much of the experimental details can be found in their paper, 28 they will not be repeated here so as to maintain conciseness.…”

The Effect of Palm Oil Biodiesel-Neat Diesel (B10-B50) Mixing Ratio on Physical Mechanism of Fuel Deposits Developed on Heated Al Surface

“…The physicochemical properties of fuel that were frequently discussed in the literature were the density, kinematic viscosity, heating value, flash point, cetane number, cloud point, and pour point [32,33]. The amount of generated deposit is dependent upon the fuel type and different parts of the combustion chamber may experience different deposit growth mechanisms as a result of the fuel's physical characteristics [34,35], in this study the tested fuels were differentiated according to certain blend ratios. In general, when the biodiesel ratio in the fuel mixture is increased, the density and kinematic viscosity also increase.…”

A numerical study of the effects of oxy-fuel combustion under homogeneous charge compression ignition regime

“…In addition, low combustion temperature can also cause incomplete conversion of fuel to CO2, thereby reducing efficiency and increasing CO and HC emissions. To solve these shortcomings, a large number of combustion control strategies have been proposed and examined both experimentally and numerically that can be organized into four main categories including variable compression ratio [16][17], variable intake conditions [18][19][20], regulated Exhaust Gas Recirculation (EGR) [21][22][23][24] and adjustable fuel blends [25][26][27][28].…”

“…To solve these shortcomings, a large number of combustion control strategies have been proposed and examined both experimentally and numerically that can be organized into four main categories including variable compression ratio, 16,17 variable intake conditions, 18–20 regulated Exhaust Gas Recirculation (EGR), 21–24 and adjustable fuel blends. 25–27…”

“…To solve these shortcomings, a large number of combustion control strategies have been proposed and examined both experimentally and numerically that can be organized into four main categories including variable compression ratio, 16,17 variable intake conditions, [18][19][20] regulated Exhaust Gas Recirculation (EGR), [21][22][23][24] and adjustable fuel blends. [25][26][27] As mentioned earlier, the application of oxy-fuel combustion with CCS technology has been mainly used on gas turbines and power plants and only a few studies have attempted to apply this strategy on IC engines. The current CFD study has been performed as a part of a European project named RIVER (funded by the Interreg North-West Europe) to explore the effects of oxy-fuel combustion on combustion characteristics and engine operating conditions in a diesel engine under the Homogenous Charge Compression Ignition (HCCI) mode.…”