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The article discusses the possibility of using glycerol as an additive to the engine fuel in order to reduce the tendency of combustion knock, and thus to increase the octane number of a given fuel. Experimental tests were carried out on the UIT-85 research engine with a variable compression ratio from eight to eleven to test the intensity of the knock. The completely renewable fuel—the blend of glycerol with butanol in the ratio of 25 and 75%, respectively—was tested. A comparative analysis of the knock intensity was conducted with gasoline 95 and N-butanol tested as reference fuels. The developed method for knock analysis using the proposed knock indicator was also presented. The experimental results proved the proposed blend of N-butanol and glycerol reduces the knock intensity by more than 50% in the spark-ignition engine at a compression ratio of 10, maintaining engine performance at a similar level as it was for a gasoline-fueled engine. The results confirmed the thesis on the reduction of knock intensity when adding glycerol to N-butanol. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents results and discussion on syngas combustion in a spark ignited internal combustion engine driving a power generator (16kW/1500rpm). The syngas applied as the engine fuel is produced by gasifying municipal sewage sludge. Unlike fermentation biogas, the syngas obtained from sewage sludge gasification is found a fuel, which generates several difficulties (non-stable combustion, misfiring events) while burning in the SI engine. The analysis of cycle-by-cycle engine run shows that the engine working on syngas features will run unsteadily due to the occurrence of misfiring events caused by the relatively low calorific value of the syngas. Thus, combustion of such a syngas in the SI IC engine can generate malfunctions. Therefore, the syngas was enriched with methane at various ratios starting from 0% up to 60% by volume. The impact of methane addition on the engine performance and exhaust emission was also presented in the paper. As investigated, 40% methane enrichment in the syngas was found sufficient amounts to obtain satisfactory engine run. Thus, in practice, the syngas from sewage sludge gasification is a troublesome fuel, but can satisfactorily be applied to the SI engine when enriched with natural gas or biogas. [Copyright &y& Elsevier]

Investigation of a new type of fuel for the internal combustion engine, which can be successfully used in both the power generation and the automotive industries, is presented in this article. The proposed fuel is a blend of 75% n-butanol and 25% glycerol. The engine tests conducted with this glycerol–butanol blend were focused on the performance, combustion thermodynamics, and exhaust emissions of a spark-ignition engine. A comparative analysis was performed to find potential similarities and differences in the engine fueled with gasoline 95 and the proposed glycerol–butanol blend. As measured, CO exhaust emissions increased, NOx emissions decreased, and UHC emissions were unchanged for the glycerol–butanol blend when compared to the test with sole gasoline. As regards the engine performance and combustion progress, no significant differences were observed. Exhaust temperature remarkably decreased by 3.4%, which contributed to an increase in the indicated mean effective pressure by approximately 4% compared to gasoline 95. To summarize, the proposed glycerol–butanol blend can be directly used as a replacement for gasoline in internal combustion spark-ignition engines. [ABSTRACT FROM AUTHOR]

The paper presents results from an investigation focused on toxicity content in the exhaust gases emitted by an internal combustion compression ignition engine fueled with glycerol-ethanol blends at ratio of 50/50% by volume. The innovative issue of this engine is the application of two high pressure injectors for injecting both glycerol-ethanol blend and diesel pilot fuel at high pressure (over 200 MPa). As known, glycerol is considered a byproduct from biodiesel production technologies, hence its cost is relatively low compared to other renewable alternative fuels which can be applied as fuels to the reciprocating piston engines. It was found that the toxic components UHC, NOx and CO were below the maximum allowed limits. Both NOx and smoke emissions were strongly reduced with increasing glycerol-ethanol fraction in the fuel. Summarizing, a fueling strategy such as that proposed in this paper makes it possible to effectively and environmentally friendly combust crude glycerol in compression ignition engines working in a heat and power cogeneration unit. Exhaust gas emission tests conducted in this case confirmed the usability of this technology to be implemented into practice. [ABSTRACT FROM AUTHOR]