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In order to study the effects of air bulk motion and methane injection strategies on the development and pollutant levels of dual-fuel combustion, an intense experimental campaign was performed on a diesel common rail research engine with variable inlet configurations. Activating only the swirl or the tumble inlet valve of the engine, or both of them, it was possible to obtain, inside the cylinder, three different bulk flow structures. The air-methane mixture was obtained injecting the gaseous fuel into the inlet manifold varying its pressure and the injector position, either very close to the inlet valves, in order to obtain a stratified-like mixture, or more upstream, to obtain a homogeneous-like mixture. By combining the two different positions of the injector and the three air bulk flow structures, seven different inlet setup have been tested, at different values of engine speed and load.

This paper deals with numerical investigations concerning the working behavior of a hydraulic impact machine. Attention is focused on the moving elements inside the casing of the breaker, taking the main targets to be achieved by the designer into account. On one hand, there is the operating performance optimization, with particular care devoted to the impact energy of the breaker; on the other hand, the energy conversion efficiency, related to the power transmission, in order to minimize the power requirement to the feeding system. Use of a parameterized numerical model is made in order to better understand the effects of parameters characteristic of distributor and striking mass on breaker performance and to achieve possible improvements in both impact energy and efficiency. The key-variable, which leads to better performance, is found to be the working pressure.

The effects of several operating parameters on dual fuel combustion at light load were investigated by means of direct endoscopic observation of the process. Therefore, an intense experimental campaign was performed on a single cylinder diesel common rail research engine, converted to operate in dual fuel mode and equipped with optical accesses and variable intake configuration. Three bulk flow structures of the charge were induced inside the cylinder by activating/deactivating the two different inlet valves of the engine (i.e. swirl and tumble). Methane was injected into the inlet manifold at different pressure levels and varying the injector position. In order to obtain a stratified-like air-methane mixture, the injector was mounted very close to the inlet valve, while, to obtain a homogeneous-like one, methane was injected more upstream.

An adaptative energy management strategy for series hybrid electric vehicles based on optimized maps and the SUMO (Simulation of Urban MObility) predictor is presented here. The first step of the investigation is the off line optimization of the control strategy parameters (already developed by the authors) over a series of reference mini driving cycles (duration of 60s) obtained from standard driving cycles (UDDS, EUDC, etc) and realistic driving cycles acquired on the ITAN500 HEV. The optimal variables related to each mini driving cycle are stored in maps that are then implemented on the ITAN500 vehicles. When the vehicle moves, a wireless card is used to exchange information with surrounding vehicle and infrastructure. These information are used by a local instance of the SUMO traffic prediction tool (run on board) to predict the driving conditions of the HEV in the future period of time T=60s.

The effect of the shape of the bowl on the combustion process and emissions of a Natural Gas - Diesel dual fuel engine is analyzed. The simulation of the dual fuel combustion is performed with a modified version of the KIVA3V code where diesel is treated as the main fuel and a further reacting specie is introduced as methane (CH4). The auto-ignition of the pilot is simulated with a modified version of the Shell model and the first stage of the combustion, related to the pilot burning process, is simulated with the Characteristic Time Combustion model. When the temperature of the mixture reaches a certain threshold, a kernel of combustion is initialized. Until the kernel reaches a nominal radius the combustion of CH4 is prevented. The combustion of CH4 is simulated with a turbulent characteristic time too. Numerical models were chosen as a compromise between accuracy and computational time.

In the present study, the influence of pressure waves propagating in the ducts of common rail injection systems on engine out emission has been investigated. The pressure waves originated by the closure of the injectors are characterized by an amplitude that can easily be greater than 10 MPa. When a multi injection strategy is adopted such fluctuations can strongly affect fuel delivery rate of subsequent injections and therefore emission levels and fuel consumption. The paper reports the results of an experimental investigation that has been carried out on a single cylinder engine equipped with a common rail electronically controlled high pressure injection system and an optical access, via endoscopes, for the visualization of soot and combustion process. The used injection strategy consisted of pilot and main injection. To allow the start of the main injection on a local pressure peak or valley without changing injection timing, injection system ducts of different length were used.

Theromophotovoltaic generators are a convenient solution to extend the range of commercial electric vehicles. High efficiencies and small volumes are required for this application. This paper shows how this problem can be addressed by using a new generation of photovoltaic cells based on quantum low-dimensional structures. Their advantage over the conventional (single gap) cells are remarkable, particularly for the conversion of narrow-band infrared radiation, produced by a combustor coupled to a selective emitter at about 1500K-1800K.

This investigation describes the results of an experimental and numerical research project aimed at comparing mileage and CO2 emissions from two different commercial versions of Daimler AG Smart ForTwo car: conventional (gasoline) and electric (ED). The investigation includes numerical simulations with the AVL CRUISE software package and on-board acquisitions. A data acquisition system has been designed for this purpose and assembled on board of the Smart ED. The system is composed by a GPS antenna with USB interface, two current transducers, a NI-DAQ device and a netbook computer with a LabView-VI. This system provided on-board information about driving cycle and current flows, gathered simultaneously by GPS, transducers and NI-DAQ. The system was also used to evaluate the losses of energy during the recharge of the electric car. The two cars have been tested over a wide range of driving conditions related to different routes, traffic conditions and use of on-board accessories (i.e.