4 research outputs found
Slow Dynamic Slope method in internal combustion engine benchmarking
Get PDFEnlarged engine control complexity made the full-factorial steady-state testing approach extremely time consuming and hardly applicable under actual industry demands. Slow dynamic slope (SDS) method is one of many approaches with a potential for considerable testing time savings, with its own benefits and drawbacks. This paper puts in focus SDS approach and evaluates its applicability, potentials and accuracy for fast estimation of engine steady-state maps. The presented research is based on an extensive experiment conducted on a small passenger car compresion ignition engine. Being the method that uses quasi-stationary sweeping of the engine, SDS test cycle durations in the range from 120-600 seconds are used in order to test the method and draw conclusions on its applicability. It is shown that well shaped SDS testing cycle can provide a rather good estimate of the steady-state operating points very quickly, with a negligible or very small loss of accuracy. The analysis is conducted both on fast responding variables and those that are heavily influenced by process inertia. This led to some suggestions on how to form a criterion for the SDS gathered data quality evaluation and SDS testing cycle correction
A thermodynamic work cycle simulation of a syngas-fueled engine
Get PDFSprovedena je simulacija radnog procesa motora SUS koji koristi sintezni gas kao gorivo u simulacionom okruženju AVL BOOST. Cilj simulacije je sticanje uvida u očekivane radne parametre motora. Studija takođe daje uvid u toplotni bilans motora koji omogućava dimenzionisanje uređaja za rekuperaciju otpadnih toplota u kogenerativnom pogonu. Jedan turbopunjeni, 6-cilindarski gasni motor čini osnovu nad kojom je sprovedena numerička studija. Za modelovanje procesa oslobađanja toplote korišćen je Vibeov model sa korelacionim parametrima koji uzimaju u obzir uticaj sastava smeše i ugla pretpaljenja na ukupno trajanje sagorevanja i oblik diferencijalnog toka oslobađanja toplote. U radu je data i jednostavna metodologija za utvrđivanje potrebne radne zapremine motora za dati protok sinteznog gasa. Dobijene vrednosti srednjeg efektivnog pritiska kao i stepena korisnosti motora su značajno manje u poređenju sa motorima koji koriste prirodni gas, ali upotreba sinteznog gasa može predstavljati zanimljivu alternativu, naročito u slučaju korišćenja kogenerativnog postrojenja.A syngas-fueled engine work cycle simulation has been conducted in the AVL BOOST environment in order to gain some insights into the expected engine performance and efficiency parameters. The study also provides the energy balance that will dictate the design of engine coolant and exhaust gas heat recuperation systems. A turbocharged six-cylinder gas engine serves as the basis on which the numerical studies have been conducted. A Vibe-based heat release model, customized to take into account the effect of excess-air ratio and ignition timing variations on the combustion duration and MFB curve shape is used to predict the heat release rate. A simple methodology for determining the total engine displacement for a given fuel production rate is also presented. The resulting brake mean effective pressure and efficiency parameters are lower than on a comparable natural gas-fueled engine but syngas is still an interesting alternative, particularly for cogeneration units
A method for quick estimation of engine moment of inertia based on an experimental analysis of transient working process
Get PDFThis paper presents an unconventional approach in a fast estimation of the overall engine inertia based on engine testing under transient condition (acceleration and deceleration) with simultaneous in cylinder working process analysis and friction losses estimation. The presented procedure is based on a single slow dynamic slope full load engine speed sweep test which, coupled with a simple lumped-mass engine dynamometer model, provides correct overall engine inertia estimation. Compared with the more conventional approaches in deriving information on engine inertia, besides its speed and accuracy, presented procedure provides more in depth information on both engine's dynamic response and friction as a surplus
Indoor temperatures affected by phase-change materials
Get PDFEnergy costs are rapidly rising around the world and it is important to find a way to reduce energy consumption. Energy consumption in buildings can account for up to 40% of total energy consumption in developed European countries due to an increase in living space per person, an increase in the need for air conditioning, an increase in the number of appliances used in households, and other factors. Due to the increasingly frequent high temperatures during the summer and the increase in electricity consumption, it is very important to find a way to decrease indoor temperatures in urban residential buildings without using more energy, given the severe energy crisis that has engulfed Europe and the high percentage of energy and electricity consumption in the residential sector. Installation of phase changeable materials is one method for improving the thermal envelope of a building by increasing the thermal capacity of the envelope and thus affecting the reduction of indoor temperature oscillations and, consequently, reduction of summer electricity consumption. In this study, the TRNSYS software package was used to simulate and compare the indoor air temperature in typical detached houses built in period 1946 and 1970 in the Belgrade area, for both, the case without and the case with installed phase change (PCM). It was shown that incorporating a PCM with a melting temperature of 25?C into the inter-floor construction of the house could significantly improve comfort conditions by reduce indoor temperature fluctuations during the warm period without consuming additional energy. When the temperature outside is around 30?C, the maximum air temperature in the house drops by about 2?C
