# Effects of Propanol on the Performance and Emissions of a Dual-Fuel Industrial Diesel Engine
## 2 Experimental Setup
### Fuels Characteristics  
The fuels used in the research are diesel (C\({}_{14}\)H\({}_{30}\)) and propyl alcohol (C\({}_{3}\)H\({}_{7}\)OH). Selected properties of fuels are presented in Table 3.  
Diesel is a typical fuel commonly used to power automotive diesel engines, compliant with the EN 590 standard, and offered at petrol stations in European countries. It is a mixture of liquid hydrocarbons and is obtained in the distillation processes of crude oil. In the case of diesel fuels, the most important parameter is the cetane number, which determines the susceptibility of a given type of fuel to spontaneous combustion. The standards define the minimum cetane number of diesel fuels sold, guaranteeing proper engine operation, at about 51. Propanol is an organic compound from the group of alcohols with three carbon atoms in the molecule, and it is colorless and has the properties of a flammable liquid. It is characterized by excellent disinfecting, cleaning, and degreasing properties. It is chemically neutral to plastics. It can be obtained by catalytic oxidation of propane. Propanol (propyl alcohol) is much less toxic and less volatile than, for example, methanol. It can be used as fuel in spark ignition engines without major modernization. The calorific value (LHV) of propanol slightly \begin{table}
\begin{tabular}{c c c} \hline
**Equipment Name** & **Type** & **Precision** \\ \hline In-cylinder pressure sensor & Kistler 6061 SN 298131 & \(\pm\)0.5\% FS, range: 0–25 MPa \\ \hline Charge amplifier & Kistler 5011 & \(\pm\)3\% FS, range for 10 V FS: \(\pm\)10... \(\pm\)999,000 pC \\ \hline Data acquisition module & Measurement Computing USB-1608 HS & 16 bits resolution, sampling frequency 20 kHz \\ \hline  & & CO: \(\pm\)0.06\% vol., \\  & & HC: \(\pm\)12 ppm vol., \\ Emission equipment & Bosch BEA 350 & CO\({}_{2}\): \(\pm\)0.5\% vol., \\  & AVL Smokemeter 415 SE & NO: \(\pm\)25 ppm vol. \\  & & Soot: \(\sigma\leq\pm\)0.005 FSN + 3\%, \\  & & range 0–10 FSN \\ \hline \end{tabular}
\end{table} 
Table 2: The main instruments and equipment of the test. exceeds 30 MJ/kg and is approx. 25% lower than that of gasoline or diesel. Propanol has a high-octane number of about 118, but due to its high production cost, it is not commonly used to power spark ignition engines. Similar to other alcohols, it is an oxygenated fuel and contains 26.6% oxygen. The alcoholic fuel, which is propanol, is characterized by a low cetane number, a lower value of the stoichiometric air to fuel ratio, a higher value of the heat of vaporization and the temperature of self-ignition, and a lower energy density, compared to diesel and gasoline. The low cetane number makes it impossible to use propanol as an independent fuel in compression ignition engines. The engine tests were carried out at a constant load, presented as a constant value of mean indicated pressure (IMEP = 0.75 MPa). The use of propyl alcohol, a fuel with a lower calorific value compared to diesel, resulted in an increase in the total mass of fuels supplied to the engine per one power cycle along with an increase in alcohol content. Figure 2a shows the change in the total fuel dose and the change in mass fractions of co-combusted fuels. Propyl alcohol, as an oxygenated fuel, introduced additional oxygen and hydrogen to the engine cylinder. Thus, both the carbon to oxygen (C/O) ratios and the carbon to hydrogen (C/H) ratios were changed. The relationship between elemental carbon, oxygen, and hydrogen in the combusted fuel has a significant impact on the exhaust emissions of a reciprocating engine. Figure 2b shows the masses of individual fuel components (carbon, hydrogen, and oxygen) burned in a dual-fuel engine, as well as the relationships between carbon and hydrogen and between carbon and oxygen.