Evaluation of Liquefied Petroleum Gas as a Fuel Input in a Mechanical Injection Diesel Internal Combustion Engine
Authors: Sarmiento Fabian , Moran Andrés , Ron Pablo 
Published: April 2022

In this research, the performance of an internal combustion engine with an adapta-tion for liquefied petroleum gas (LPG) injection was analyzed. The automotive indus-try works on the development and improvement of internal combustion engines, both in their design, metrics, technology incorporation, among others. Part of the research is focused on testing different fuels to reduce emissions and preserve or improve op-erating parameters. Recent studies have shown that the incorporation of LPG in the combustion mixture of diesel engines reduces pollutant emissions and increases pow-er output. In Latin America, there is a significant population of mechanical injection engines that use fuel with 500 ppm of sulphur, so it is relevant to study alternatives to improve combustion. This study evaluated the vehicle performance with a 1998 diesel internal combustion engine, which was adapted to an LPG injection system as input fuel. Torque, power, opacity, particulate matter, and fuel consumption tests were carried out using the IM240 cycle, using different diesel and LPG mixtures. The results show that there is an increase in torque values 22.06 lb.ft and power of 13.47 HP at 300 rpm with a mixture of 53.43% diesel and 46.57% LPG. Opacity had an increase to 82% at the critical point, while there is a decrease in fuel consumption. In addition, as the LPG / Diesel ratio increases, the engine exhibits strong internal explo-sions as a result of delayed ignition, which could cause engine damage. Finally, the results are contrasted with those of other research studies and it is concluded that the incorporation of LPG injection systems in mechanical injection diesel engines, alt-hough it increases the power and torque of the engine, there may be cases where a reduction in the emission of polluting gases or particulate matter is not obtained and normal operation is not guaranteed, especially in mixtures with high LPG proportion. Environmental pollution is a problem of global concern, so the way to reduce pollu-tion and pollutant emissions is constantly being investigated while maintaining or improving parameters such as torque and power. To achieve this goal, mechanical modifications, the vehicle in general, or fuel quality is regulated. Another alternative that has been studied is the mixture of fuels using diesel cycle engines with LPG. In, for example, tests were carried out on fuel-air premixture (PCCI) diesel engines by adding LPG to the combustion mixture, resulting in a reduction in particulate matter emissions and an improvement in auto-ignition resistance. On the other hand, in tests were conducted on injection ignition diesel engines, where power increase, NOx reduc-tion, and CO increase were determined for diesel and LGP fuel mixtures. In LPG and diesel mixtures were tested on an electronically controlled BOSCH VP3 engine up to 75% LPG, which achieves a reduction in fuel consumption of approximately 3.5% by increasing the gas injection angle achieving ignition at a point very close to the opti-mum. Finally, in tests were carried out by adding LPG to the mixture in dual-fuel Diesel CNG engines where the author reports a reduction in power.