The „downsizing” phenomenon has grown and has led to the technological and efficient use of the supercharger systems. Despite this, conventional turbocharging systems have a transitional response due to the exchange of power with the engine and affect the elasticity of the engine. An electrically actuated turbocharging system can eliminate this shortfall, transient operation, without loss of interference, as the response is instant to the electric drive. A power recovery system can be added to increase overall efficiency. The study provides an overview of the influence of the compression ratio of a compression ignition engine to which an electric power-driven axial compressor has been attached. The results showed that the implementation of an electric compressor and a high compression ratio contribute to increasing yields and reducing losses in the operating cycle.
This study aimed to highlight the mass flow and boost pressure performance of an electrically operated axial compressor. This compressor proposed and developed by its authors[1] was mounted on a diesel engine, which is fitted to a VW Golf 4. A mathematical model was developed in MathCad for the overall calculation of this compressor, determining the boost pressure and the theoretical air flow. The mathematical model also highlights the increase in the boost in each stage of the compressor, but also the mechanical work consumed. The compressor was made of the following parts: fan 1 which is designed to take the air and to direct it axially into the second stage, where is the second fan with a smaller diameter and a number of higher revolutions, the control unit which allows the speed of each fan to be adjusted and the part to be protected against electrical shock. To determine the air flow, a diaphragm has been created which has been fixed by 6 screws at the compressor outlet, fitted with holes for measuring the difference in pressure. In this study, the pressure at several characteristic points of the compressor will be measured using an integrated differential sensor assembly. LabVIEW program was used to determine characteristic values according to the speed of the axial compressor and pressure variation can be seen on a laptop interface during compressor operation. After determining the mass flow, the turbocharging pressure can also be determined from the calculation.
We report the generation of unprecedented 10 PetaWatt laser pulses obtained from each of the two beamlines of the High Power Laser System (HPLS) of ELI-NP (Extreme Light Infrastructure – Nuclear Physics) research infrastructure. The laser system is a hybrid system made of a double CPA based on amplification within Titanium Sapphire crystals combined with an OPCPA with a parametric amplification stage boosting the energy to 10 mJ at the entrance of the second CPA. A XPW filter is also inserted between the two CPA and in combination with the OPCPA improves the temporal contrast of the pulses by typically 7 orders of magnitude. The spectral effects occurring during amplification such as gain narrowing and wavelength shifting are compensated through the use of spectral filters. Final amplification stages are involving large aperture Ti:Sapphire crystals (up to 200 mm) which are pumped by high energy frequencydoubled Nd:Glass lasers delivering each 100 J of green light. Laser beams have been amplified respectively up to 332 J and to 342 J of pulse energy at 1 shot per minute without any occurrence of ASE and transverse lasing thanks to index matching fluid surrounding the crystal over is entire length and pump deposition management over the time before each beam pass within the Ti:Sapphire crystal. We have demonstrated full aperture compression by metric gratings of these amplified pulses down to 22.6 fs and therefore made the full demonstration for the first time ever of 10 PW capability from a laser system.
Up to present, air cooling systems still raise several unsolved problems due to conditions imposed by the environment in terms of temperature and pollution levels. The present paper investigates the impact of the engine cooling degree upon its performances, as important specific power is desired for as low as possible fuel consumption. A technical solution advanced by the authors[1], consists of constructing a bi-flux compressor, which can enhance the engine’s performances. The bi-flux axial compressor accomplishes two major functions, that is it cools down the engine and it also turbocharges it. The present paper investigates the temperature changes corresponding to the fresh load, during the use of a bi-flux axial compressor. This compressor is economically simple, compact, and offers an optimal response at low rotational speeds of the engine, when two compression steps are used. The influence of the relative coefficient of air temperature drop upon working agent temperature at the intercooler exit is also investigated in the present work. The variation of the thermal load coefficient by report to the working agent temperature is also investigated during engine cooling. The variation of the average combustion temperature is analyzed in correlation to the thermal load coefficient and the temperatures of the working fluid at its exit from the cooling system. An exergetic analysis was conducted upon the influence of the cooling degree on the motor fluid and the gases resulted from the combustion process.
Internal combustion engines can be supercharged in order to enhance their performances [1-3]. Engine power is proportional to the quantity of fresh fluid introduced into the cylinder. At present, the general tendency is to try to obtain actual specific powers as high as possible, for as small as possible cylinder capacity, without increasing the generated pollution hazards. The present paper investigates the impact of replacing a centrifugal turbo-compressor with an axial double-rotor bi-flux one [4]. The proposed method allows that for the same number of cylinders, an increase in discharged airflow, accompanied by a decrease in fuel consumption. Using a program developed under the MathCad environment, the present work was aimed at studying the way temperature modifies at the end of isentropic compression under supercharging conditions. Taking into account a variation between extreme limits of the ambient temperature, its influence upon the evolution of thermal load coefficient was analyzed considering the air pressure at the compressor cooling system outlet. This analysis was completed by an exergetical study of the heat evacuated through cylinder walls in supercharged engine conditions. The conducted investigation allows verification of whether significant differences can be observed between an axial, dual-rotor, bi-flux compressor and centrifugal compressors.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.