Experimental Investigation of Effect 0f Hydrogen and Higher Alcohol Blends on Engine Characteristics of Crdi Diesel Engine

Abstract

The depletion of fossil fuels had alarmed the researchers to search for new sustainable renewable fuels. Biofuels and hydrogen are the most promising sustainable and renewable alternatives to diesel fuel. In the present renewable energy world, alcohols are gaining prime importance due to their nature of production and fuel properties. The experiment was conducted in a CRDI CI engine test rig at a constant speed of 2000 rpm and the load is varied from 20% to 80% in step of 20%. The main aim of the present investigation is to study the effect of higher alcohol and hydrogen on combustion, performance, and emission characteristics of CRDI CI engine, and also the present investigation aims to reduce the NOX emission by adopting the EGR and SCR of NOX techniques. Initially, a comparative analysis of 1-Pentanol and 1-Hexanol is done on engine characteristics of CRDI CI engine at standard engine conditions to find the best higher alcohol. From the results, it is noted that 1-Hexanol performs well compare to 1-Pentanol and from the results, the 30H70D blend is chosen as an optimized blend for further study. With the use of an optimized 1-Hexanol blend, further improvement in engine characteristics is done by varying the injection time to 9 ̊BTDC and 15 ̊BTDC. Compared to standard (12 ̊BTDC) and late injection (9 ̊BTDC), advanced injection time (15 ̊BTDC) showed better combustion, performance, and emission characteristics. Both BTE and BSEC showed only 1.77% and 1.8% reduction at 15 ̊BTDC compared to pure diesel operation. The optimization of alcohol blend and injection time showed a positive impact on performance and emission. The CO emission was almost equal to pure diesel operation and NOX emission was still lower compared to diesel fuel operation. The 1-Hexanol blends showed lagging in combustion and performance compared to pure diesel operation. For further improvement in combustion and performance, enrichment of hydrogen fuel through an inlet manifold is adopted. From the experimental investigation, it was noted that 10 lpm of hydrogen enrichment is optimum and it gives better compatibility with 1-Hexanol blends. The enrichment of hydrogen reduces the ignition delay and improves the poor combustion, performance, and emission characteristics of the 1-Hexanol blend in the engine. The hydrogen enriched 1-Hexanol blend showed an increment of 4.9% of BTE at 80% load compared to 1-Hexanol/diesel alone. Exhaust gas recirculation is the in-cylinder strategy and SCR of NOX is an after-treatment technique to reduce the NOX emissions from the engine. These two methods are adopted in this investigation to reduce the NOX emission from the engine with the optimized hydrogen-enriched 1-Hexanol blend. Here 10% and 20% EGR rate and Pt-Pd SCR catalyst iv are used for the investigation. The 10% EGR rate and Pt-Pd SCR catalyst showed a positive effect on the reduction of NOX. The main intention of the present investigation was to study the compatibility of 1- Hexanol in a diesel engine without compromising in performance and emission characteristics of the CI engine. The present investigation was also intended to study the new combustion and emission control technologies, which can be co-developed with alternative fuels. Finding and securing a renewable alternative energy source for diesel fuel and providing a compatible technology to work with alternative fuels in the engine were also conscious efforts. The present investigation was also focused to create huge options in the production and supply of alternative fuels.