# Medium-Energy Synthesis Gases from Waste as an Energy Source for an Internal Combustion Engine
## 3 Experimental Methods  
The following are the selected compositions of synthesis gases resulting from the above analysis of the production of synthesis gases produced from waste. This article analyses twelve synthesis gases which, with their lower heating value (8-12 MJ/kg), fall into the category of medium-energy gases. The applications of low-energy synthesis gases produced by waste gasification as used in the internal combustion engine were published by the authors of this article in 2020 [43]. The following figure (Figure 1) shows the ternary diagrams representing the composition of the selected and analysed synthesis gases, numbered 1 to 12, relative to the proportion of inert gases. Synthesis gas SG3 was the only gas with the highest proportion of inert gases (60% vol.). The basic physico-chemical properties of experimentally proven synthesis gases are given in Table 2. The individual synthesis gases are in ascending order, depending on the increasing lower mass heating value of the fuel. As is well known, the power parameters of the internal combustion engine will be influenced in particular by the lower volume heating value of the fuel and air mixture (\(\text{LHV}_{\text{mixture}}\)), as this determines how much energy is supplied in the cylinder over one cycle, assuming the same volumetric efficiency. Other important factors affecting the overall engine performance parameters are the fuel burn-up rate and, last but not least, the volumetric amount of products generated after combustion. All experimental measurements were performed on a Lombardini LGW702 atmospheric internal combustion engine (Table 3). The two-cylinder ignition engine was created as a modification from the original diesel version by adjusting the head of the internal combustion engine, as well as the compression ratio, the intake manifold, and the method of preparing the mixture. The piston crowns were lathe turned and grinded to achieve a compression ratio of 12.5 from the original ratio of 22.8, [44]. This internal combustion engine was used for the experiments with the aim to reduce the operating costs of fuels for the experimental measurements. The scheme of the experimental equipment together with a description of the individual components is shown in the following figure (Figure 2). The internal combustion engine was connected to an electric induction dynamometer MEZ Vsetin 1 DS 736 V (from MEZ Vsetin, Czech Republic), which can operate in both motor and generator modes of operation. Gaseous fuel mass flow was measured with a flow-meter from Bronkhorst (device designation: F-113 AC-M50-AAD-55-V). Nitrogen was set as the reference gas for this flow-meter. To obtain the actual synthesis gas mass flow rate, the mass flow was multiplied by the mass factor coefficient specific to each synthesis gas mixture composition [45]. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline
**Name** & **Unit** & **CH\({}_{4}\)** & **SG1** & **SG2** & **SG3** & **SG4** & **SG5** & **SG6** & **SG7** & **SG8** & **SG9** & **SG10** & **SG11** & **SG12** \\ \hline CH\({}_{4}\) & [\% vol.] & 100 & 10 & 0 & 20 & 10 & 0 & 20 & 10 & 20 & 10 & 20 & 20 & 10 \\ \hline H\({}_{2}\) & [\% vol.] & 0 & 25 & 40 & 10 & 35 & 50 & 5 & 20 & 15 & 30 & 10 & 25 & 40 \\ \hline CO & [\% vol.] & 0 & 20 & 30 & 10 & 10 & 20 & 30 & 40 & 20 & 30 & 40 & 10 & 20 \\ CO\({}_{2}\) & [\% vol.] & 0 & 20 & 25 & 10 & 20 & 25 & 20 & 25 & 20 & 25 & 20 & 25 \\ \hline N\({}_{2}\) & [\% vol.]