Improving pollutant emissions in diesel engines for heavy-duty transportation using retarded intake valve closing strategies

A combined theoretical and experimental study has been carried out to determine the real potential of reducing pollutant emissions in a HD diesel engine by means of retarding the intake valve closing. The effects produced by this alteration of the basic operation cycle have been examined by a preliminary modelling study, and from the obtained results, a modified camshaft was manufactured with a delayed intake valve closing of 60 crank angle degrees. Single-cylinder engine tests were carried out with this modified camshaft, and the emissions and fuel consumption were recorded. The results showed that the retarded intake valve closing can enhance the premixed combustion phase, and thus simultaneously reduce soot and NOx emissions. Moreover, the combustion process attained is extremely tolerant to exhaust gas recirculation, and by adoption of this measure, Euro-5 emissions limits can be achieved at the tested conditions without after-treatment.     

Full vehicle simulation using thermomechanically coupled hybrid neural network shock absorber model

In the case of full vehicle models, the technique of multi-body simulation (MBS) is frequently used to study their highly non-linear dynamic behaviour. Many non-linearities in vehicle models are induced by force elements like springs, shock absorbers, bushings and tires. Commonly, spline functions are used to represent the force responses of these components. If the non-linear relationships are more complicated, the spline approximations are no more accurate. An alternative approach is based on empirical neural networks which are based on the mathematical approximation of measured data. It is well known that neural networks are able to represent and predict complex component responses accurately. The aim of this paper is to perform a dynamic full vehicle simulation using a thermomechanically coupled hybrid neural network shock absorber model. In this shock absorber model, the spline approach is combined with a temperature-dependent neural network. Based on a displacement-controlled excitation on a four post test rig in the ADAMS/Car MBS software, a rugged test track is simulated. In this way, the front and rear shock absorbers are dynamically loaded with comfort-relevant frequencies in the range of 0.75-30 Hz and velocity amplitudes up to 2 m/s. By the simulation, stability of the hybrid neural network model is demonstrated. Furthermore, the damping force, the vertical acceleration of the chassis and the required simulation times are compared. The standard spline approach is used as a reference.     

Measuring the potential for automobile fuel savings in the US: The impact of obesity

High rates of oil consumption and obesity in the US have become important socioeconomic concerns. While these concerns may seem unrelated at first, growing obesity rates in the US increase fuel consumption by adding passenger weight to vehicles. This paper estimates the additional amount of fuel (i.e., gasoline) consumed annually by noncommercial passenger highway vehicles in the US due to passenger overweight and obesity. The mathematical model presented in this paper estimates that as many as one billion additional gallons of gasoline are consumed each year due to overweight and obesity in the US, accounting for up to 0.8% of the fuel consumed by these vehicles annually. This additional fuel consumption causes carbon dioxide emissions of up to 20 billion pounds or more, accounting for up to 0.5% of the annual carbon dioxide emissions in the transportation sector.     

A game-theoretic analysis of competition among container port hubs: the case of Busan and Shanghai 1

Countries throughout the world, and especially within Asia, are investing heavily in container port infrastructure in the hopes of capturing a larger share of global shipping activity for their economies. Many existing ports are emphasizing developing the capacity to serve as a hub port, building deepwater berths with large terminals to facilitate transfer of containers from feeder ships to mother ships for intercontinental transport. We develop a game-theoretic best response framework for understanding how competitor ports will respond to development at a focus port, and whether the focus port will be able to capture or defend market share by building additional capacity. We apply this model to investment and competition currently occurring between the ports of Busan and Shanghai.     

Analysis of the capabilities of a two-stage turbocharging system to fulfil the US2007 anti-pollution directive for heavy duty diesel engines

This article presents a two-stage turbocharged heavy-duty diesel (HDD) engine designed to fulfil the US2007 anti-pollution directive. This directive imposes very restrictive limits on the NOx and particle emissions of HDD engines. In this work, the possibility of combining particle traps in the exhaust line to reduce soot emissions with very high EGR rates to reduce NOx emissions is considered. This new generation engine implements two-stage turbocharging in order to improve the bsfc when the engine is working on steady conditions as well as to optimize the engine transient response. After carrying out the tests, the results were analyzed and the engine settings were adjusted to maximise its behaviour and minimise pollutant emissions. NOx and soot emission peaks were also analyzed at engine transient conditions in order to keep them under certain levels, and thus maintain the overall pollutant emissions to a level that is as low as possible. In summary, a double-stage turbocharging configuration can greatly improve engine driveability (between 23% and 36% depending on engine speed), while reducing NOx emissions during transient evolution without increasing opacity peaks beyond the stated limits.     

Hydrographic conditions affecting two fishing grounds of Mallorca island (Western Mediterranean): during the IDEA Project (2003–2004)

This paper describes the hydrographic conditions observed during six surveys carried out during 2003 and 2004, in the framework of the “IDEA Project” (acronym for “Influence of oceanographic structure and dynamics on demersal populations in waters of the Balearic Islands”). The surveys were developed on the shelf and slope of Mallorca Island, in particular in two fishing grounds at the north and south of the Mallorca channel. Periodic movements of the fishing fleet between these two areas have been regularly reported, suggesting a seasonal variability of the resources which could be in turn associated with the hydrodynamic variability. With this motivation, water masses affecting these grounds have been identified and their seasonal variability has been studied. Different oceanographic and environmental conditions have been found between the two fishing grounds. These differences are related to the presence of mesoscale structures, associated with the Western Mediterranean Intermediate Water (WIW) at the north of the Ibiza channel and big gyres detached from the Algerian Current. The former has been shown to have influence on the regional oceanic circulation and the latter could affect the progress of fresh Atlantic Water (AW) towards the channels and make possible the presence of high salinity values at intermediate waters at the south of Mallorca Island. Historical data from other oceanographic cruises carried out in the region are finally used to discuss the interannual variability of these mesoscale structures.     

Combustion development of a Bi-Fuel engine

Environmental improvement and energy issues are increasingly becoming more important as worldwide concerns. Natural gas is a good alternative fuel that can help to improve these issues because of its large quantity and clean burning characteristics. This paper provides the experimental performance results of a Bi-Fuel engine that uses Compressed Natural Gas as its Primary fuel and gasoline as its secondary fuel. This engine is a modification of the basic 1.4-liter gasoline engine. Generally, on the unmodified base engine, torque and power for CNG fuel are considerably lower than gasoline fuel. In this paper, the influence of fuels on wall temperature, performance and emissions are investigated.