# Combustion and Emission Characteristics of a Biodiesel-Hydrogen Dual-Fuel Engine
## 2 Experimental Setup and Procedure  
### Research Engine and Apparatus  
The paper presents the result of experimental research on the co-combustion of biodiesel (B100) with hydrogen in a compression-ignition IC engine. The tests were carried out on an industrial, single-cylinder, air-cooled, two valve engine. The engine worked at a constant speed of 1500 rpm. The research engine was equipped with additional fuel supply systems. Hydrogen was added using a Servojet SP05 IS1 gas injector controlled by a control system ensuring precise control of opening time. Biodiesel was injected directly into the engine's combustion chamber. The injection timing was not changed. The engine worked with a constant load which was defined by indicated mean effective pressure (IMEP) with value of IMEP = 0.7 MPa. On-line indication was carried out. On the basis of this process was determined power, torque, rotational speed, indication mean effective pressure and was observed pressure traces. In addition, the test stand is equipped with a measuring system with a dynamometer. A diagram of a test stand equipped with an engine is shown in Figure 1. The test engine was also equipped with an indication system, a measurement system for gaseous fuel and air consumption. The system for measuring pressure changes in the cylinder included a pressure sensor, load amplifier, encoder for crankshaft angular position and A/D system for recording measurement data.  
Table 1 presents test engine data. Test engine is air cooled one cylinder engine with compression ratio equal to 17.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Engine & 1 CA90 Andoria \\ Type of engine & Four stroke compression ignition \\ Number of cylinders & 1 \\ Bore & 90 mm \\ Stroke & 90 mm \\ Displaced volume & 573 cm\({}^{3}\) \\ Number of valves & 2 \\ Compression ratio & 17 \\ Engine speed & 1500 rpm \\ Diesel injection & Direct injection \\ Hydrogen injection & Port injection \\ Diesel injection pressure & 21 MPa \\ Diesel injection timing & 343 deg \\ \hline \hline \end{tabular}
\end{table}
Table 1: Main engine parameters.  
Figure 1: Test stand.  
The study used the following measurement apparatus:  
* Pressure sensor Kistler 6061, range 0-25 MPa, linearity \(<\pm\)0.5% FS,
* Charge amplifier Kistler 511, range \(\pm\)10... \(\pm\)999,000 pC for 10 V FS, error \(<\pm\)3%, linearity \(<\pm\)0.05% FS,
* Data acquisition module, Measurement Computing USB-1608 HS-16 bits resolution, sampling frequency 20 kHz with software [23],
* Air rotor flowmeter Common CGR-01 G40 DN50, measuring range 0.65-65 m\({}^{3}\)/h, accuracy class 1, \(\mathrm{H_{2}}\) rotor flowmeter Common CGR-01 G10 DN50, measuring range 0.25-25 m\({}^{3}\)/h, accuracy class 1, \(\mathrm{Exhaust\ gas}\) analyzer: THC, CO, \(\mathrm{CO_{2}}\), \(\mathrm{O_{2}}\)-Bosch BEA 350 (THC: range 0-9999 ppm vol. accuracy: 12 ppm vol.; \(\mathrm{NO_{x}}\): range 0-5000 ppm accuracy: 10 ppm.; CO: range 0-10 %vol. accuracy: 0.06 %vol.; \(\mathrm{CO_{2}}\): range 0-18 %vol. accuracy: 0.4 %vol.; \(\mathrm{O_{2}}\): range 0-22 %vol. accuracy: 0.1 %vol.; \(\mathrm{\lambda}\): range 0.5-9.999 accuracy: 0.01),
* AVL Smoke Meter: measurement range 0-10 FSN, detection limit: 0.002 FSN or 0.02 mg/m\({}^{3}\), standard deviation 1\(\sigma\leq\pm\)(0.005 FSN + 3%).  
Table 2 presents the main properties of used fuels, biodiesel and hydrogen. Biodiesel is characterized by a higher value of cetane number compared to diesel fuel, which promotes the self-ignition process in the engine cylinder. Biodiesel also has a low autoignition temperature relative to hydrogen. High hydrogen laminar flame speed will reduce the combustion time and should increase the efficiency of the engine. When using biodiesel and hydrogen, no petroleum fuels were use.