*2.4. Engine Performance Test Procedure*

A four-stroke 163 cc overhead valve OHV single-cylinder, horizontal-shaft, water-cooled SI engine was used to perform the tests. The specifications of the engine are shown in Table 2. The engine is mated to a generator with maximum load 3 kW and operated at 220 V–50 Hz and connected to 6 (six) lamps (500 watts each) that used a load bank to control the load of the engine during the performance test. The function of the generator is to supply the voltage and electric current to power the 3000-watt six-lamp configuration when the engine consumes the fuel at varying speeds. A schematic diagram of the engine experimental setup is given in Figure 3. The engine test was conducted under speed variation from 1500 to 3000 rpm with 500 rpm intervals for each type of fuel. A tachometer, voltmeter, and clamp meter was used to determine the engine rotation, the voltage input, and the electrical

current of engine load, respectively. The experiment was repeated three times, and the mean value was calculated for each sample. Figure 4 shows a schematic diagram of the engine experimental setup.

**Table 2.** The specification of the engine.

**Figure 4.** Schematic diagram of engine experimental setup.
