Review of scientific research regarding PPO, tallow and RVO as diesel engine fuel

Pure Plant Oil (PPO) is extracted from the seeds of oil producing plants. It is often further processed to make bio-diesel in order to reduce the fuel’s viscosity, thus making it suitable for direct use in diesel engines. This process adds to the fuel production energy consumption, increases the fuel cost and generates undesirable by-products. The viscosity of PPO can also be reduced by heating the fuel using heat from the engine with simple heat exchangers. This fuel may also be more suitable for smaller markets, e.g. the Irish market, whereby Irish bio-fuel producers would be able to supply “un-transesterified” fuel, maximising their profits, because of the lower production cost. The following paper describes benefits of PPO over bio-diesel fuel, it outlines the stark lack of literature regarding the optimisation of PPO fuelled diesel engines. Furthermore aspects such as the importance of fuel feedstock quality and storage are investigated in order to establish the current status of PPO, RVO and tallow in this regard on engine performance. It was found that while much literature exists regarding bio-diesel degradation and storage, very little was available regarding the un-transesterified fuel and the effects of this fuel’s quality on engine performance and degradation.