A review of fuel additives' effects and predictions on internal combustion engine performance and emissions

<abstract> <p>In recent years, there has been an increasing interest in additives for fuel research in the field of internal-combustion engine. Many studies have been conducted to improve the performance and emissions of the engine. Many kinds of additives in the form of solid, liquid, and gas have been used. The objective of this review is to examine the effects of having additives on the performance and emission of internal combustion engine. Additives such as alcohol, hydrogen, and metal oxides are proven to be successful to improve performance or reduce emission. Results from selected papers are discussed and summarised in a table. With the new development in nanotechnology, many researchers have shown an increased interest in carbon-based. In recent years, there has been an increasing interest in additives for fuel research in the field of internal-combustion engines. Many studies have been conducted to improve the performance and emissions of the engine. Many kinds of additives in the form of solids, liquids, and gases have been used. The objective of this review is to examine the effects of having additives on the performance and emissions of an internal combustion engine. Additives such as alcohol, hydrogen, and metal oxides are proven to be successful in improving performance or reducing emissions. Results from selected papers are discussed and summarised in a table. With the new developments in nanotechnology, many researchers have shown an increased interest in carbon-based nanoparticles such as multi-walled carbon nanotubes (MWCNT) and single-walled carbon nanotubes (SWCNT). Lately, with the discovery of graphene production techniques, graphene nanoplatelets (GNP) have also been applied as fuel additives. In addition to understanding the effects of the additives on the engine performance and emissions, researchers extended the research to predict the outcome of the performance and emissions. nanoparticles such as multi-walled carbon nanotube (MWCNT) and single-walled carbon nanotube (SWCNT). Lately, with the discovery of graphene production techniques, graphene nanoplatelets (GNP) also has also been applied as fuel additives. In addition to the understanding the effects of the additives to the engine performance and emissions, researchers extended the research to predict the outcome of the performance and emissions. The experiments involving the predictions efforts are summarised in a table. From the summary, it is found that the prediction of the GNP as fuel additive effects to the performance and emissions has not yet been explored. This gap is an opportunity for researchers to explore further.</p> </abstract>

Numerical Study on the Performance and NOx Emission Characteristics of an 800cc MPI Turbocharged SI Engine

The main purpose of this study is to optimize engine performance and emission characteristics of off-road engines with retarded spark timing compared to MBT by repurposing the existing passenger engine. This study uses a one-dimensional (1D)-simulation to develop a non-road gasoline MPI turbo engine. The SI turbulent flame model of the GT-suite, an operational performance predictable program, presents turbocharger matching and optimal operation design points. To optimize the engine performance, the SI turbulent model uses three operation parameters: spark timing, intake valve overlap, and boost pressure. Spark timing determines the initial state of combustion and thermal efficiency, and is the main variable of the engine. The maximum brake torque (MBT) point can be identified for spark timing, and abnormal combustion phenomena, such as knocking, can be identified. Spark timing is related to engine performance, and emissions of exhaust pollutants are predictable. If the spark timing is set to variables, the engine performance and emissions can be confirmed and predicted. The intake valve overlap can predict the performance and exhaust gas by controlling the airflow and combustion chamber flow, and can control the performance of the engine by controlling the flow in the cylinder. In addition, a criterion can be set to consider the optimum operating point of the non-road vehicle while investigating the performance and exhaust gas emissions accompanying changes in boost pressure With these parameters, the design of experiment (DoE) of the 1D-simulation is performed, and the driving performance and knocking phenomenon for each RPM are predicted during the wide open throttle (WOT) of the gasoline MPI Turbo SI engine. The multi-objective Pareto technique is also used to optimize engine performance and exhaust gas emissions, and to present optimized design points for the target engine, the downsized gasoline MPI Turbo SI engine. The results of the Pareto optimal solution showed a maximum torque increase of 12.78% and a NOx decrease of 54.31%.

Trade-off Study on Economy and Environmental Aspects of a Dual Fuel Diesel Engine using Diesel Additive and Producer Gas

Experiments are performed on a diesel engine working in single fuel mode using fossil diesel (FD) as well as 5% and 10% (v/v) di-ethyl ether (DEE) additives with FD as fuels as well as in dual fuel mode using the above fuels as pilot fuels along with producer gas (PG) as primary fuel. This study aims to draw comparative analyses of engine combustion, performance and emission characteristics using the above fuel combinations to establish the most suitable fuel strategy for a diesel engine. The study revealed greater control over nitric oxide (NO) and smoke opacity in dual fuel mode compared to single fuel mode operations. Addition of DEE with FD, produced lower HC and CO emissions, comparable NO emissions along with reduced smoke opacity compared to FD in both modes of operation. Further, in dual fuel mode operation, the diesel percentage energy substitution (PES) reduced with increase in DEE content in the blends. The tradeoff study involving engine performance and emissions with respect to the cost of operation revealed that the fuel strategy used in dual fuel mode operation delivered better engine performance along with reduced NO emission and smoke opacity at lower operational cost compared to all the considered fuel strategy in single fuel mode operation. Especially, FD+5% DEE+PG and FD+10% DEE+PG fuel strategies were found to be the most suitable dual fuel mode combinations in a diesel engine in terms of their superior engine performance, lower emissions along with better economy.