Browse Topic: Environment

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One way to decarbonize spark-ignition (SI) engines is to use alternative fuels to improve thermal efficiency. Compressed biomethane gas (CBG), mainly composed of methane and carbon dioxide produced from food waste, has attracted attention as an alternative fuel, but its carbon dioxide content is indeterminate. This study investigates the effects of carbon dioxide content on engine performance (thermal efficiency, etc.), emission characteristics, and turbulent burning velocity using a CBG surrogate fuel mixed with methane and carbon dioxide. A single-cylinder SI engine is used as the test engine, and experiments are conducted under different load conditions with a constant crank angle of 50% mass fraction burned (CA50). Engine performance is analyzed based on heat balance from in-cylinder pressure analysis. Emission characteristics are measured using an emission gas analyzer. Using the boundary conditions obtained from the experiments, parameters such as unstretched laminar burning
Kobayashi, TakumaShimizu, TaketoshiYoshimura, KeiSok, RatnakKusaka, Jin
Ozone (O3) was introduced into the intake air in a natural gas fueled engine ignited by micro-pilot of diesel fuel, to utilize the reactive O-radicals decomposed from the O3 for the promotion of the combustion and for improvements in the thermal efficiency and exhaust emissions. Experiments were carried out in a single cylinder engine to elucidate the effects of the ozone addition under the lean burn conditions. A supercharger was employed to increase the intake air amount and vary the equivalence ratio of natural gas. The experimental results showed that the O3 addition has a limited effect on the ignition of the diesel fuel injected near top dead center, while the heat release during the flame propagation in the natural gas/air mixture was increased at the lower equivalence ratio of natural gas. Further the ignition of natural gas was promoted, resulting in the increase of the combustion efficiency and the degree of constant volume heat release. The cooling loss and the NOx emissions
Kobashi, YoshimitsuMiyata, ShokiKawahara, NobuyukiInagaki, Ryuya
The use of hydrogen in port fuel injection (PFI) engines faces challenges related to abnormal combustions that must be addressed, especially in transient operation. The in-cylinder air-to-fuel ratio and the amount of trapped exhaust gas have a significant impact on the probability of abnormal combustion as well as NOx emissions, and should be real-time monitored in hydrogen engines. Thus, the real-time estimation of the composition and thermodynamic state of the trapped gas mixture is crucial during transient operations, although highly challenging. This study proposes an on-line real-time physics-based MIMO (Multi-Input-Multi-Output) model to accurately estimate the amount of trapped air and exhaust gas in the cylinder at the intake valve closing (IVC) event, based on the instantaneous in-cylinder pressure measurement. With proper estimation accuracy, the injector can be controlled to correctly provide the amount of fuel necessary to achieve the target air-to-fuel ratio (AFR) and
Galli, ClaudioCiampolini, MarcoDrovandi, LorenzoRomani, LucaBalduzzi, FrancescoFerrara, GiovanniVichi, GiovanniMinamino, Ryota
The transfer of conditions and regulations for RDE testing from passenger cars to motorcycles is a non-trivial undertaking. Motorcycles exhibit significant differences in construction and usage compared to cars, necessitating a distinct set of requirements for equipment and methodology. Currently available PEMS are hindered by their relatively large size and weight due to the embedded measurement technology and external power supply. The weight of, at least 50kg, poses a substantial additional load, leading to a deviation and, on average, higher load collective of the engine during RDE measurement rides. Beyond these structural parameters, the actual propulsion system and subsequent exhaust system introduce another challenge when employing PEMS on motorcycles. An unfavorable combination of the ratio of engine displacement to the volume of the exhaust system and long or unequal ignition intervals leads to pulsations, which has a considerable impact on the differential pressure-based
Schurl, SebastianKeller, StefanLankau, MathiasHafenmayer, ChristianSchmidt, StephanKirchberger, Roland
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