The present experimental investigations deal with the spark plug location and its effect on the performance and emission of a 100% raw biogas-fueled variable compression ratio engine. Different measurements of performance, combustion, and emission parameters are used to analyze the effect of four spark locations protruded inside the clearance volume (viz. 0, 2, 5, and 10 mm). The protrusion of the spark plug by 2 mm is observed to be optimum for compression ratios 8, 9, and 10. For this optimum spark plug location, engine efficiency and fuel economy are found to be higher. Faster combustion, in this particular case, has led to early and higher peak cylinder pressure and burnt gas temperature. Lower emissions of hydrocarbons and carbon monoxide have verified the optimality of 2 mm protrusion location of the spark plug for all the compression ratios. Thus, present investigations recommend minor protrusion of the spark plug to assist the combustion process, to enhance the performance and lowering the emission of a biogas-fueled engine.
Currently, more than 95% of biodiesel is being produced from edible vegetable oils which may affect the sustainability of biodiesel industries. Rubber seed oil (RSO) is one of the promising non-edible oil for biodiesel synthesis. Higher free fatty acid content of RSO was reduced by ultrasonic assisted esterification reaction. Non-conventional techniques, ultrasonic horn and ultrasonic bath for transesterification of esterified RSO (ERSO) were studied to enhance the yield of rubber seed oil methyl esters (ROME). The effect of transesterification parameters; molar ratio (MR) of methanol/ERSO (3:1-13:1), reaction time (5-50min) and heterogeneous catalyst Ba(OH) 2 ·8H 2 O (2-10wt%of feedstock) on conversion of RSO were investigated and optimized for maximum yield of ROME. The physico-chemical properties of ROME and its various blending with diesel (RDXX) were estimated to suite diesel engine for efficiency (BTE) was achieved at 80% load with RD10 (28.36%) compared to neat diesel (24%) and a drastic improvement of overall 13% increase at all loads. Maximum exhaust gas temperatures for biodiesel blends were found to be lower than neat diesel with rise in pressure by about 4% which ultimately shows slight improvement in the net heat release rate. The emissions of CO, CO 2 and NO X were reduced with the use of ROME blends.
Present investigations deal with development of a novel variable compression ratio (VCR) mechanism and its implementation in a small and relatively large size single-cylinder engines. Operation of this mechanism is found to be smooth and effective in the running condition of the engine as well. This mechanism, when incorporated in the small size spark ignition HONDA engine, portrayed improvement in engine performance with increment in compression ratio (CR) for petrol and kerosene. Their respective optimum CRs 5.02 (petrol) and 5.27 (kerosene) are higher than the base value 4.8. In case of large size KIRLOSKAR engine, the present VCR mechanism is found to be useful while operating with liquefied petroleum gas (LPG), where measurements showed that combustion duration is lower with LPG for CR 9.79 as compared with base value 9.0. The present experiments clearly demonstrate the usefulness of VCR mechanism in improving engine performance for a given fuel and broadening the range of alternative fuels burnt in the engine. Ease of fabrication, simplicity in installation, accessibility in troubleshooting and smooth run-time alterations are the advantages with the current novel mechanism.
The usage of biogas as a potential fuel in a spark ignition (SI) engine is the theme for the present study. The exhaust gas recirculation (EGR) is a significant technique for improving the performance of the SI engine. Thus, the novelty of the experimental investigations lies in implementing the EGR technique for emission control of the biogas-fueled engine. The raw biogas (52% methane and 47% carbon dioxide), obtained from a biogas digester (using cow dung as the source), was the engine fuel for a four stroke, water cooled, variable compression ratio SI engine set-up. Here, the engine performance and emission related parameters were measured. When operated in the raw biogas mode at an optimum spark timing of 45 °CA before the top dead center, the engine produced maximum torques of 11 N m, 14 N m, and 16 N m for compression ratios 8, 9, and 10, respectively. The effect of different EGR rates on the emission control was also investigated. The net heat release rate without EGR was found to be 22.623J/°CA at 368 °CA, which further reduced to 14.233 J/°CA at 386 °CA for EGR10. Moreover, it was clearly evident that low EGR rates (below 10%) were effective in reducing NOX significantly, with minor compromise in power and brake specific fuel consumption. But the emissions of hydrocarbon and carbon monoxide were found to be higher with the increase in EGR. The operation of the engine with medium or heavy EGR rates resulted in issues related to intense pressure fluctuations and large cycle-to-cycle variation in performance. Thus, the present investigations recommend the use of low EGR (below 10%) in a biogas-based engine for lower NOX emission and better fuel efficiency.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.