The effect of the CO2 ratio in biogas on the vibration and performance of a spark ignited engine

In the present study, a four-cylinder diesel engine was modified to operate with a spark plug and used to detect the effect of the biogas CO2 content on the vibration of the engine. The experiments were carried out with biogas containing 13% and 49% CO2 at 1.5-9 kW with 1.5 kW load increments at a steady 1500 rpm speed. The amplitude of the engine vibration at all three axes increased as the CO2 ratio in the biogas and the engine load increased. On the other hand, by decreasing the CO2 ratio and increasing the engine load, cylinder pressure increased and brake specific fuel consumption decreased. The highest amplitude of engine vibration for all loads was observed at the lateral axis.