The waste plastics generation is increasing globally with approximately of 3.5 MMT annual.This includes LDPE, HDPE, PET, PS and PET; If the same trend continuous, this leads to 25000 MMT waste plastics generated by the year 2040 as per literature. Hence all the researchers should focus on various methods of discarding the waste plastics and converting this into a useful form. The biofuel generated from the waste plastic will be available at lesser price than the present day fuel price. This fuel will be satisfying all the global standards and can be operated in the exisisting engines without modification. This review paper mainly focusing on various methods and converting the waste plastics into fuel. It also gives clear knowledge on the overview of PWG, PWD, PWI and PWR. Based on the literature review it is cleared that pyrolysis process is one of the most prominant method of converting the waste plastics into fuel. Based on the experimental work done on the engines has proved that BTE is improved by 2 - 5% and emissions were reduced 1-3.5% compared to other conventional fuel. These results motivates the researchers to convert the waste plastics into fuel which leads to a cleaner environment and an improved economy for the country.

Bharath’s sixth stage emission benchmark norms are stringent as per the global Emission norms, and their implementation is a great concern. The current Bharath stage VI emission norms were implemented on 1 April 2020. The aim of this work is to study the engine performance and emissions when the engine is fuelled by a new and unique bio-diesel. The engine selected for this experimentation is a Kirloskar , single-cylinder, 4-stroke and water-cooled, common rail direct injection (CRDi) diesel engine. The biodiesel was drawn from the Acacia seeds, which are available in plenty most of the places in South India, especially like Andhra Pradesh, Tamil Nadu and Karnataka . The oil was extracted from the dry acacia seeds and sent through a motorised expeller. The oil expelling efficiency is 19%, the available oil content is 220 ml, out of it 190 ml of oil was extracted, whereas with a hand-operated expeller, it was 16%; hence there is an improvement of 3%. The oil has been verified with FFA content and had 1.0%. FFA content single-step transesterification process is selected, which has yielded 97%. Experiments were conducted at 500 bar with a single injection, 500 bar with the main injection 15 degrees b TDC, pilot injection 23 degrees b TDC and 500 bar with B10 a single injection and 200 bar with the main 15 degrees b TDC, pilot injection 23 degrees b TDC. The results were observed when the engine was running with 15 degrees main injection and 23 degrees pilot injection strategy.

Multiple injection strategy is a vital strategy to reduce the soot and NO_x emissions concurrently. The multiple injection strategy can enhance the air/fuel mixture, combustion and exhaust emission characteristics by providing a small amount of fuel before the main injection. Among all types of alternate fuels, biodiesel has emerged as an eco-friendly fuel for the diesel engines. This paper is focusing on the effect of pilot injection strategies on diesel engine say timing (−30° bTDC to −50° bTDC) and by varying the fuel quantity (5–15%). The performance, combustion and emission characteristics of Palm-munja biodiesel/diesel blend (B20) were investigated on CRDI diesel engine. The experimentations were carried out on a constant speed by varying loads from 0 to 100%. The experimental results show that as an increase in pilot injection timing there is a reduction in the in-cylinder pressure, whereas soot and NO_x emissions decrease as the pilot injection timing increases. As the pilot injection fuel quantity increases, the in-cylinder pressure and NO_x emission increase, whereas soot emission decreases.

The main aim of this present work is to test a novel biofuel on a diesel engine. The various steps involved in this research work is collection of seeds, sun drying, mechanical expelling and transesterification. This biofuel is mixed with the diesel along with n-butanol. This experimental work deals with the investigation of lotus biodiesel with different blends in addition to n-butanol as an ignition improver. The blends starts with pure diesel (D100), D90L8B2 (90% diesel 8% Lotus biodiesel and 2% butanol), D80L16B4 (80% diesel 16% Lotus biodiesel and 4% butanol), D70L24B6 (70% diesel 24% Lotus biodiesel and 6% n-butanol and L100 (100% Lotus biodiesel). The experimental results were observed at full load condition (100%) was better for the fuel D70L24B6; achieved the fuel efficiency by 28%, which is closer to diesel mode, whereas D70L24B6 attained the lowest brake specific fuel consumption; decrease in BSFC of 7% as compared to D100. The in cylinder pressure was found as 73bar for the fuel D70L24B6, which is closer to D100. After the fuel D100, the maximum HRR was found 84.1 kJ for the fuel D70L24B6. The parameter such as shorter ignition delay occurred for all alchololic lotus biodiesel blends compared to D100. The lowest CO emissions were found for the fuel L100, which decreases CO emissions by 17.2% compared to D100. The lowest carbon dioxide emissions were found for the fuel D90L8B2 fuel, decrease in 5.49% compared to D100. The lowest HC emissions at full load conditions were found for the fuel L100, decrease in HC emission rate by 16.1 % compared to pure diesel. The lowest NOx emissions were found for the fuel L100, but there is an increase in NOx emission rate by 8% compared to diesel because of higher oxygen content in biodiesel.