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Abstract: This paper presents further results of the study on fundamental combustion characteristics of gaseous fuels simulated for a biogas produced through a biomass gasification process with a catalyzer. The main work focuses on combustion characteristics of H2–CO blended fuel and the effect of CO2 dilution on it in a spark-ignition engine under the condition of WOT, MBT and a constant speed of 1500 rpm. Equivalence ratio were limited to lower than 0.8 in order to avoid excessive high combustion temperature to damage the engine, and lean conditions were maintained during the experiment to get acceptable economy and emissions. The results show that the BMEP decreases with an increase in dilution rate. The COV of IMEP is lower than 10% under most conditions, while H2 and CO2 have the opposite influence on brake thermal efficiency. CO2 dilution combustion could induce to remarkable decreasing in NO x emission with little decrease in brake thermal efficiency, which benefits for biomass gaseous fuel application. If 500 ppm of NO x emission and 26% of brake thermal efficiency could be viewed as accepted level, the accepted operation range of H2–CO mixture have been obtained. [Copyright &y& Elsevier]

Diffusion of battery electric vehicles and fuel cell hybrid electric vehicles can contribute to reduce passenger light-duty vehicle fleet CO 2 emissions. However, barriers such as higher vehicle capital cost and lack of electricity and hydrogen infrastructure prevent their deployment. A vehicle stock turnover model was used to assess the impact of mini-sized and zero-emission vehicle diffusion on passenger light-duty vehicle fleet energy and material consumption, CO 2 emissions and cost, focusing on Japan. 2050 passenger light-duty vehicle fleet energy consumption and tank-to-wheel CO 2 emissions in the base scenario are 48.7 and 51.9% lower than the 2012 values. Diffusion of mini-sized and battery electric vehicles provides the largest energy consumption and CO 2 emissions reductions, 64.7, and 87.8% compared with the 2050 baseline values. Incremental cost of zero emission vehicles is reduced through downsizing. The 2050 net cash flow for battery electric vehicles diffusion is reduced from 15.9 to −16.7 billion USD/year if downsizing is applied; while in the case of fuel cell hybrid electric vehicle diffusion, downsizing reduces the 2050 net cash flow from −12.5 to −47.8 billion USD/year. Thus, shifting to mini-sized zero emission vehicles provides the quadruple benefit of reducing energy and material consumption, CO 2 emissions and cost. [ABSTRACT FROM AUTHOR]

The article studies the effect of aerodynamic tabs on the screech problem in Supersonic jets. Environmental compliance is one of the requirements in supersonic transporters particularly the reduction of noise. In the study, tabs are mounted to the nozzle exit in order to reduce the mass flow of the area due to the blockage effect. It was then concluded that when the secondary jet is used, the screech noise is reduced.

Electric-drive vehicles, including hybrid electric vehicles, plug-in hybrid electric vehicles, battery electric vehicles, fuel cell electric vehicles and fuel cell hybrid electric vehicles, are emerging as less polluting alternatives to internal combustion engine vehicles. Therefore, it is important to assess their penetration in the vehicle market in the future. A ‘two-step’ approach is used to estimate the optimum market penetration of lightweight and electric-drive vehicles in the long-term and the impact on the light-duty vehicle fleet, focusing on Japan. First, an optimization model is used to estimate the vehicle market composition in 2050. Then, a vehicle stock turnover model is used to estimate light-duty vehicle fleet energy and material consumption, CO 2 emissions and cost. Internal combustion engine vehicles and hybrid electric vehicles dominate in the Base scenario. Fuel cell hybrid electric vehicles dominate when low cost is prioritized. Shift to battery electric vehicles occurs when low CO 2 emissions are prioritized. CO 2 emissions are reduced 56.9% between 2012 and 2050 in the Base scenario. Lightweight mini-sized battery electric vehicle diffusion has the largest CO 2 emissions reductions, 87.3% compared to the 2050 baseline value; with the net cash flow peaking at 10.2 billion USD/year in 2035 and becoming negative after 2044. [ABSTRACT FROM AUTHOR]

Electric-drive and lightweight vehicles can reduce CO 2 emissions in road passenger transportation. However, maximum reductions are limited by the extent of their diffusion. A vehicle fleet stock turnover model was developed to study the impact of powertrain electrification, vehicle size reduction and lightweight materials substitution on light-duty vehicle fleet energy consumption, CO 2 emissions and cost; and used in the case of Japan. Vehicle types included internal combustion engine vehicles, hybrid electric vehicles, battery electric vehicles, and fuel cell hybrid electric vehicles; using two glider types, conventional and lightweight; available in three vehicle size classes, normal, compact and mini-sized vehicles. Diffusion of mini-sized lightweight battery electric vehicles has the largest potential for tank-to-wheel energy consumption and CO 2 emissions reductions, 70.6 and 92.2%, compared to the 2050 baseline values; with a net cash flow larger than zero until 2045. In contrast, diffusion of mini-sized lightweight fuel cell hybrid electric vehicles has the lowest net cash flow by 2050, with negative values from 2033 and potential tank-to-wheel energy consumption and CO 2 emissions reductions of 55.4 and 82.9% compared to the 2050 baseline values. Lightweighting reduces significantly the capital cost of battery electric vehicles and fuel cell hybrid electric vehicles, favoring their deployment. [ABSTRACT FROM AUTHOR]

The article offers information on the successful usage of aerodynamic tab jet noise suppressors at the time of takeoff in hypersonic nozzle. It discusses hypersonic nozzle, aerodynamic tab and acoustic measurement. It also talks about several topics including effects of aerodynamic tab position, geometry and working gas.

Decarbonizing road freight transport is difficult due to its reliance on fossil fuel internal combustion engine vehicles (ICEVs). The role of powertrain electrification in achieving deep decarbonization in road freight transport was studied using a vehicle stock turnover model, focusing on Japan. Twelve vehicle types were considered; combining four powertrains, ICEV, hybrid electric vehicle (HEV), battery electric vehicle (BEV) and fuel cell electric vehicle (FCEV); and three vehicle size classes, normal, compact and mini-sized vehicles. A scenario-based approach was used; considering a Base scenario, and three alternative scenarios targeting powertrain electrification. Between 2012 and 2050, tank to wheel CO2 emissions decrease 42.8% in the Base scenario, due to the reduction of vehicle stock, the improvement of vehicle fuel consumption and the adoption of HEVs. Diffusion of FCEVs in normal vehicles and BEVs in compact and mini-sized vehicles achieves the largest tank to wheel CO2 emissions reductions, up to 44.6% compared with the 2050 baseline value. The net cash flow is positive over the whole time horizon, peaking at 6.7 billion USD/year in 2049 and reaching 6.6 billion USD/year by 2050. Powertrain electrification is not enough to achieve any of the CO2 emissions reduction targets in road freight transport. [ABSTRACT FROM AUTHOR]