Biofuel, a cost-effective, safe, and environmentally benign fuel produced from renewable sources, has been accepted as a sustainable replacement and a panacea for the damaging effects of the exploration for and consumption of fossil-based fuels. The current work examines the classification, generation, and utilization of biofuels, particularly in internal combustion engine (ICE) applications. Biofuels are classified according to their physical state, technology maturity, the generation of feedstock, and the generation of products. The methods of production and the advantages of the application of biogas, bioalcohol, and hydrogen in spark ignition engines, as well as biodiesel, Fischer–Tropsch fuel, and dimethyl ether in compression ignition engines, in terms of engine performance and emission are highlighted. The generation of biofuels from waste helps in waste minimization, proper waste disposal, and sanitation. The utilization of biofuels in ICEs improves engine performance and mitigates the emission of poisonous gases. There is a need for appropriate policy frameworks to promote commercial production and seamless deployment of these biofuels for transportation applications with a view to guaranteeing energy security.

An Overview of the Classification, Production and Utilization of Biofuels for Internal Combustion Engine Applications

Experimental and numerical study the effect of combustion chamber shapes on combustion and emissions characteristics in a heavy-duty lean burn SI natural gas engine coupled with detail combustion mechanism

Internal combustion engines power the great majority of automobiles on the road today. However, the challenges of complying with other propulsion systems and near-zero-emission standards are inevitable. Current stringent emission standards are becoming universal and globally harmonized test cycles are being recommended. As per the BS-VI norms, PM and NOx emissions are to be reduced by 80% and 70%, respectively for diesel engines. Indian OEMs are integrating the Euro-VI emission control technologies into their vehicle and also limiting the production of diesel engines, especially in the passenger sector. In this respect, it is necessary to enhance the current understanding of the improvements in combustion chambers, after-treatment devices, and potential low-carbon fuels for sustainable transport mobility. This paper comprehensively outlines the prospects of future fuels, modified combustion systems, and after-treatment devices. The fuel composition of both fossil and biofuels plays a vital role in altering the exhaust soot and NOx characteristics. Thus an overview of hydrogen formulated fuels, the optimal combinations of the fuel–engine–after-treatment systems are also highlighted. In the end, a brief discussion concerning the total life cycle analysis is also presented in this paper. The review concludes by suggesting potential fuels and technologies for lowering the emission levels and provides directions for future work to address the challenges facing alternate energy resources for automotive applications, particularly in India. 

A comprehensive review on the current trends, challenges and future prospects for sustainable mobility

The influence of hydrogen addition on the combustion characteristics of a common-rail CI engine fueled with waste cooking oil biodiesel/diesel blends

The increased level of air pollution has caused the automobile industry to investigate alternate greener fuels to make vehicles more environmentally friendly. This study focuses on the perf...

Lubrication, emissions, and performance analyses of LPG and petrol in a motorbike engine: a comparative study

Partial hydrogenation and hydrogen induction: A comparative study with B20 operation in a turbocharged CRDI diesel engine

CFD study and experimental investigation of piston geometry induced in-cylinder charge motion on LPG fuelled lean burn spark ignition engine

The current rate of depletion of fossil fuels has created an imbalance in the energy exchange. Stricter emission standards are enforced in order to control the environmental pollution and global warming. Both these factors have led to a shift from usage of conventional fossil fuels to other alternative resources. LPG serves as a viable alternative option owing to its suitability to fuel SI engines and its obtainability from large scale shale gas reserves. Being a gas at atmospheric condition, it offers proper homogenization and is best suited for lean-burn conditions. Adding methanol in small amount to LPG lowers the combustion temperature due to the latent heat of vaporization and improves lean operation due to oxygen content contributing in reduction of NOx. This work is focused on NOx reduction as it is hazardous and main constituent in the formation of PM, smog and acid rains. An experimental study is conducted in a single cylinder diesel engine modified to operate as SI engine at an optimized compression ratio of 10.5:1 and 1500 rpm fueled by LPG. The effects of methanol substitution were investigated in reduction of NOx emissions at 100% throttle condition by injecting 10, 20 and 30% of methanol on energy basis into the intake port of engine. The results have been analyzed with Brake Effective Mean Pressure (BMEP) as it serves as an important yardstick to compare different criteria. The experiments were performed at BMEPs of 4, 4.5,5 and 5.5 bar. There is a significant improvement in brake thermal efficiency along with decrease in the NOx emission as the percentage of methanol in the fuel goes higher. The decrease in NOx is significant ranging from 83% at 4 bar BMEP to 12% at 5.5 bar. The lean operation was also improved on addition of methanol.

Effects of Methanol Substitution on Performance and Emission in a LPG-Fueled SI Engine

Experimental Investigations on Lean Burn Spark Ignition Engine Using Methanol - Gasoline Blends

On fuel perspective, Liquefied Petroleum Gas (LPG) provides cleaner emissions and also facilitates lean burn signifying less fuel consumption and emissions. Lean burn technology can attain better efficiencies and lesser combustion temperatures but this temperature is quite sufficient to facilitate formation of nitrogen oxide (NOx). Exhaust Gas Recirculation (EGR) for NOx reduction has been considered allover but extremely little literatures exist on the consequence of EGR on lean burn LPG fuelled spark ignition (SI) engine. The following research is carried out to find the optimal rate of EGR addition to reduce NOx emissions without settling on performance and combustion characteristics. A single cylinder diesel engine is altered to operate as LPG fuelled SI engine at a compression ratio of 10.5:1 and arrangements to provide different ratios of cooled EGR in the intake manifold. Investigations are done to arrive at optimum ratio of the EGR to reduce emissions without compromising on performance. Significant reductions in NOx emissions alongside HC and CO emissions were seen. Higher percentages of EGR further diluted the charge and lead to improper combustion and thus increased hydrocarbon emissions. Cooled EGR reduced the peak in-cylinder temperature which reduced NOx emissions but lead to misfire at lower lean limits.

Jim Alexander

Papers

Partial hydrogenation and hydrogen induction: A comparative study with B20 operation in a turbocharged CRDI diesel engine

CFD study and experimental investigation of piston geometry induced in-cylinder charge motion on LPG fuelled lean burn spark ignition engine

Effects of Methanol Substitution on Performance and Emission in a LPG-Fueled SI Engine

Experimental Investigations on Lean Burn Spark Ignition Engine Using Methanol - Gasoline Blends

Influence of cooled exhaust gas recirculation on performance, emissions and combustion characteristics of LPG fuelled lean burn SI engine