Bio fuels based on vegetable oils offer the advantage being a sustainable, annually renewable source of automobile fuel. Despite years of improvement attempts, the key issue in using vegetable oil-based fuels is oxidation stability, stoichiometric point, bio-fuel composition, antioxidants on the degradation and much oxygen with comparing to diesel gas oil. Thus, the improvement of emissions exhausted from diesel engines fueled by biodiesel derived from palm oil is urgently required to meet the future stringent emission regulations. Purpose of this study is to explore how significant the effects of palm oil blending ratio on combustion process that strongly affects the vehicles performance and exhaust emissions. The engine speed was varied from 15003000 rpm, load test condition varied by Dynapack chassis dynamometer from 050% and palm oil blending ratio from 515vol% (B5B15). Increased blends of biodiesel ratio is found to enhance the combustion process, resulting in decreased the HC emissions with nearly equal of engine performance. The improvement of combustion process is expected to be strongly influenced by oxygenated fuel in biodiesel content.

This introductory study comes up with an innovative idea of using Hydroxyl gas as a fuel performance enhancer to reduce the natural sources and the overuse of fossil fuel resulting in increased pollution levels. Many researchers have used HHO gas to analyze gasoline and diesel in internal combustion engines. The main challenges of using HHO gas in engines have been identified as system complexity, safety, cost, and electrolysis efficiency. This article focuses on different performance reports and the emission characteristics of a compression ignition engine. As opposed to general diesel, this study found that using HHO gas improved brake power and torque. In all cases, an increase in braking thermal efficiency can be observed. This was due to the presence of hydrogen in HHO gas with higher calorific value than fossil fuels. At the same time, the fuel consumption unit of the engine was reduced, and the combined impact of hydrogen and oxygen helped to achieve complete combustion and improved the combustion capacity of the fuel when HHO gas was injected. The addition of HHO gas also improved the Brake Power (BP), Brake Torque (BT), Brake Specific Fuel Consumption (BSFC), and thermal efficiency while simultaneously reducing CO and HC formation. The rise in CO2 emissions represented the completion of combustion. Therefore, the usage of HHO gas in the Compression Ignition (CI) engine improved the engine performance and exhaust emissions.

The present investigation into the effect of amino acids on linoleic acid oxidation in freeze‐dried model system illustrates the existence of an autocatalytic chain reaction, in which all amino acids, except cysteine, exhibited minor antioxidant behavior. The antioxidant effect might be attributed to the absence of protonated amino nitrogen. Linoleic acid alone had an induction period of 15 hr, and on the addition of various α‐amino acids, the systems had induction periods ranging from 16‐19 hr. This increase did not exhibit any specific function for the studied amino acids. Cysteine exhibited an exceptional prooxidant effect due to the role of the HS‐group. The addition of copper at concentrations of 10‐5M and 10‐3M to the model systems composed of linoleic acid and various a‐amino acids exhibited minor and highly prooxidant effects, respectively, The prooxidant effect of these amino acids in the presence of copper might be due to amino acids‐copper complexes.

Model systems were designed to study linoleic acid oxidation in the presence and absence of various amino acids with or without cupric ions. The tested amino acids exhibited a potential prooxidant effect in linoleic acid dispersed in aqueous media. The effectiveness of various amino acids on linoleic acid oxidation decreased in the following order: cysteine > serine > tryptophan > phenylalanine > histidine > alanine. The addition of alanine, serine, phenylalanine, histidine, or tryptophan to linoleic acid showed an autocatalytic chain reaction. With cysteine, there was a linear relation between concentration of hydroperoxides and time during the early stages of oxidation. The prooxidative activity of the tested amino acids in general could be attributed to the presence of the a‐amino group in the form H3‐N‐R. The apparent difference in the prooxidative activity is mainly due to the functional groups attached in the β‐carbon atom in the amino acid molecules. The addition of cupric ions at a concentration of 10‐5M to linoleic acid catalyzed with various a‐amino acids showed that these amino acids had no significant effect. Increasing the copper concentration from 10‐5M to 10‐3M had the following effects: a shortening of the induction period of linoleic acid catalyzed by amino acids having an aromatic side chain, no effect on the induction period but an increase in the oxidation rate during the propagation step in the model systems catalyzed by alanine and serine, and in the model system containing cysteine a linear increase in the linoleic acid oxidation from the start of the reaction.

The use of natural gas as an alternative fuels are motivated from the impact in deteriorating quality of air and the energy shortage from petroleum products. Through retrofitting, CI engine runs on CNG, will be able to reduce the negative impact mainly on the use of petroleum products. However, this required the modification of the combustion chamber geometry by reducing the compression ratio to value that suits combustion of CNG. In this present studies, four different shapes and geometries of combustion chamber were designed and simulate using CFD package powered by Ansys workbench, where k-ε turbulence model was used to predict the flow in the combustion chamber. The results of turbulence kinetic energy, velocity vectors and streamline are presented. The enhancement of air-fuel mixing inside the engine cylinder can be observed, where the design with re-entrance and lower center projection provide better results compared to other combustion geometries designs.