On Alternative Fuels for Internal Combustion Engines : A study of biodiesel, gaseous methane and methanol
Abstract: This thesis covers some of the environmental impacts of internalcombustion engines running on alternative fuels. The focus of thestudies conveyed is the reduction of greenhouse gases and particleemissions, as these two factors are of great importance for the pathsthat road transportation is facing. The main area covered is heavyduty engines for truck applications, but a study on methane fuel andhow gaseous methane can be used to reduce CO2 emissions in lightduty engines is also included. The literature studies executed inrelation to the different studies and publications are based on aholistic perspective of the difficulties of implementing alternativefuels for a heavy duty application, mainly in the perspective ofgaseous fuels.The experimental studies have been performed as studies in singlecylinder engine test cell setups. The areas of investigation were:- Accelerated testing of Biodiesel injector fouling, whichcould increase the particle and CO2 emissions from theengine- Using methane to potentially reduce CO2 by up to 50%compared to gasoline in a light duty application- In-cylinder flow optimisation to improve combustionstability in a heavy duty engine and thereby lowering theCO2-emissions.- Particle emissions originating from the entrainment oflubricating oil in the combustion chamber and how reducedoil ash content can affect the particle emissions from theengine.The outcome of these studies showed that it was possible to createan accelerated test procedure capable of fouling the injector in justone day. The reduction in CO2 for the light duty engine running onmethane was possible to reach close to 50%. This was done byincreasing the compression ratio, advancing the spark anddownsizing the engine.IIThe heavy duty methane engine study indicates that there is anoptimum combination between the design parameters in thecombustion chamber in order to be able to control the combustionspeed. The relation between particle emission and engine oil ashcontent showed that the entrainment of oil into the combustionchamber made the largest impact, before the ash content causedfurther impact on particle emissions.This work is to be seen as insights into areas in which the alternativefuels may contribute to reduce the environmental impact, mainly ofCO2, of the internal combustion engine. The vision is that it will helpto provide for a greener tomorrow and a better future for many.
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