Сonversion of a diesel engine to operate on propane-butane

Abstract

The problem of reducing transportation costs by using cheaper motor fuel was addressed. Gaseous fuels (natural gas and propane-butane mixtures) are promising motor fuels. The technologies for converting gasoline engines to run on gaseous fuels have been well-developed for a long time. At the first stage of the work, the D-243 diesel engine was converted into a gas engine with spark ignition to operate on natural gas. The diesel fuel system was removed, ignition system components and gas fuel equipment were installed, and the engine's compression ratio was reduced to 12. Bench tests of the engine were conducted, during which its load and control characteristics were obtained. It was found that the power of the gas engine remained at the level of the base diesel engine, its equivalent fuel consumption was up to 19% higher due to operation on richer mixtures, and the total toxicity of exhaust gases was almost twice as low compared to the diesel engine. However, natural gas has several significant drawbacks. Therefore, the engine was converted to operate on propane-butane mixtures. An analysis of gaseous fuel properties showed that propane-butane has lower detonation resistance compared to natural gas. The knock sensor signal recording confirmed the presence of detonation during engine acceleration under load. Based on engine cycle calculations, a compression ratio of 11 was selected. The compression ratio was reduced by installing a thicker metal gasket between two standard metal-asbestos gaskets. Bench tests of the engine running on propane-butane showed an increase in equivalent fuel consumption compared to operation on natural gas and diesel fuel. This is explained by the engine running on richer air-fuel mixtures. The power remained at the level of the base diesel engine.

Keywords: diesel, gas engine, spark ignition, natural gas, propane-butane.