An Experimental Investigation of Raw Biogas Combustion in a Small Spark Ignition Engine using Cow Manure in Algeria.

Biogas from organic waste has a good potential to substitute fossil-based fuels. It is a good example of the circular bioeconomy where low quality waste is turned into a high-quality fuel, while bio-nutrients are recovered at the end of the digestion process. This renewable gas can play a vital role for future energy needs. In this study, an experimental investigation has been carried out on a 5 hp single cylinder Honda GX140 gasoline engine coupled to a TD115 Hydraulic Dynamometer, operating with raw biogas and gasoline. The biogas used to fuel the engine is produced from cow manure at mesophilic conditions. Under two engine loading conditions; 0 and 3.5 N.m, the engine performance characteristics were investigated. A significant increase in the exhaust gases' temperature and fuel mass flow rate was observed for the case of raw biogas. The results also revealed that raw biogas generated higher brake thermal efficiency and brake specific fuel consumption compared to gasoline. This will open the door for biogas to substitute partially fossil-based fuels and give positive societal effects in rural areas. [ABSTRACT FROM AUTHOR]