Search Results

Natural gas is a viable alternative to gasoline and diesel fuel because it is a clean burning fuel that is available from a large domestic reserve through a mature infrastructure. The heavy dependence of the small engine sector on oil, much of which is imported from foreign countries and the small engine sector's negative impact on the air quality in urban areas are two pervasive problems that can be helped by using Compressed Natural Gas (CNG) as a small engine fuel. In addition, CNG is typically over 80% methane, which is produced by the decay of organic material, so while natural gas is not renewable its use enables much of the infrastructure required for a methane-based renewable energy system. In order to determine the emissions benefit of using CNG as compared to gasoline in a small engine, a 750 cc 90 degree V Twin port-fuel-injected production engine rated at 29 horsepower (HP), designed and built by Kohler Inc.

This paper will review the development and results of an accelerated test established to study the engine wear observed in some engines fueled with Biodiesel Fuel (BDF). BDF is a clean burning alternative fuel that can be produced from domestic renewable resources. Its basic composition is of multiple Fatty Acid Methyl Esters (FAME) (1). These fatty acid methyl esters are an excellent source of energy but have different physical properties as compared to petroleum based diesel fuel. The differences in physical properties can lead to increased dilution of BDF in the engine oil. Petroleum based diesel fuel (PDF) has increased volatility when compared to BDF, which allows the fuel to evaporate from the engine oil through the crankcase ventilation system. The lower volatility of BDF results in a lower evaporation rate and thus comparatively higher levels of BDF dilution in the oil. This higher dilution level alters the oil's viscosity and interacts with the oil's additives.