Continuous slow dynamic slope approach for stationary base internal combustion engine mapping

Engine control optimization, with its always growing complexity, is in permanent focus of engine researchers and developers all over the world. Automotive engines are dominantly used in dynamic conditions, but generally, steady-state operating points are used for building up mathematical models which are later subject to the numerical optimization. For this purpose, a large amount of steady-state regimes needs to be evaluated through experimental work at the engine test stand, which is an extremely time and funds consuming process. Consequently, the methodology for data gathering during engine dynamic excitation could lead to significant savings at the expense of acceptable data accuracy loss. The slow dynamic slope method starting from a stationary operating point was evaluated by several authors in the past. In this paper, slow dynamic slope method with exclusively transient excitation will be presented drawing attention to some of its advantages and drawbacks. The rate of change of engine load as a main control parameter during dynamic test is of great importance for the quality of the final data and for total test duration. In this regard, several tests of different duration were applied for fixed engine speed values to cover engine speed-load usage domain. An approximation of stationary testing results obtained in this way could be used for evaluation of the map gradients and thus as a guideline for additional stationary tests based on design of experiment method

Numerical analyses of a hydraulic hybrid powertrain system for a transit bus

A dynamic programming optimization algorithm has been applied on a transit bus model in MATLAB in order to assess the fuel economy improvement potential by implementing a hydraulic hybrid powertrain system. The numerical model parameters have been calibrated using experimental data obtained on a Belgrade's public transport bus. This experiment also provided the representative driving cycle on which to conduct simulation analyses. Various functional parameters of a hydraulic hybrid system have been evaluated for obtaining the best possible fuel economy. Dynamic programming optimization runs have been completed for various hydraulic accumulator sizes, preload values and accumulator foam quantities. It has been shown that a fuel economy improvement of 28% can be achieved by implementing such a system

Numerical analyses of a hydraulic hybrid powertrain system for a transit bus

A dynamic programming optimization algorithm has been applied on a transit bus model in MATLAB in order to assess the fuel economy improvement potential by implementing a hydraulic hybrid powertrain system. The numerical model parameters have been calibrated using experimental data obtained on a Belgrade's public transport bus. This experiment also provided the representative driving cycle on which to conduct simulation analyses. Various functional parameters of a hydraulic hybrid system have been evaluated for obtaining the best possible fuel economy. Dynamic programming optimization runs have been completed for various hydraulic accumulator sizes, preload values and accumulator foam quantities. It has been shown that a fuel economy improvement of 28% can be achieved by implementing such a system

Continuous slow dynamic slope approach for stationary base internal combustion engine mapping

Engine control optimization, with its always growing complexity, is in permanent focus of engine researchers and developers all over the world. Automotive engines are dominantly used in dynamic conditions, but generally, steady-state operating points are used for building up mathematical models which are later subject to the numerical optimization. For this purpose, a large amount of steady-state regimes needs to be evaluated through experimental work at the engine test stand, which is an extremely time and funds consuming process. Consequently, the methodology for data gathering during engine dynamic excitation could lead to significant savings at the expense of acceptable data accuracy loss. The slow dynamic slope method starting from a stationary operating point was evaluated by several authors in the past. In this paper, slow dynamic slope method with exclusively transient excitation will be presented drawing attention to some of its advantages and drawbacks. The rate of change of engine load as a main control parameter during dynamic test is of great importance for the quality of the final data and for total test duration. In this regard, several tests of different duration were applied for fixed engine speed values to cover engine speed-load usage domain. An approximation of stationary testing results obtained in this way could be used for evaluation of the map gradients and thus as a guideline for additional stationary tests based on design of experiment method

A thermodynamic work cycle simulation of a syngas-fueled engine

Sprovedena 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

This 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

The c20068t gene variant in the 3 ' end of the prothrombin gene and recurrent pregnancy loss: a pilot study

Recurrent pregnancy loss (RPL) is a health problem affecting up to 5% of women of reproductive age. Several thrombophilic risk factors might contribute to RPL. To investigate relationship between a novel C20068T gene variant in the 3' end of prothrombin gene and RPL, we tested 153 women with RPL and 111 controls for the presence of this gene variant. In patients, we have detected four heterozygous (2.61%) and no homozygous carriers. In controls, no carriers were detected. Our results indicate higher prevalence of C20068T gene variant in women with RPL but this difference was not statistically significant. However, in patients who suffered 5 or more RPL, frequency of C20068T gene variant was significantly increased compared to controls (12.5% vs. 0%, P = 0.02). This is the first study which points out a possible role of C20068T gene variant in etiology of RPL, but larger studies should be carried out to confirm our findings

Impact of acquired and genetic factors on thrombophilic phenotype in FV Leiden mutation carriers

FV Leiden mutacija je veoma značajan genetički faktor rizika za pojavu venskog tromboembolizma (VTE). U okviru ove studije analizirana je klinička slika i uticaj stečenih i genetičkih faktora rizika u grupi od 100 bolesnika, nosilaca FV Leiden mutacije (95 heterozigota i 5 homozigota). Devedeset jedan bolesnik je imao VTE, sa trombozom dubokih vena donjih ekstremiteta kao najčešćom manifestacijom. Kod 68,6% žena bio je prisutan neki od stečenih faktora rizika, dok je to bio slučaj kod 28,6% muškaraca. Mutacija FII G20210A je detektovana kod 9,5%, MTHFR 677TT kod 8,4%, a obe mutacije su bile prisutne u 2,1% heterozigotnih nosilaca FV Leiden mutacije. Rezultati ove studije ukazuju na značaj poznavanja udruženih faktora rizika kod pacijenata koji su nosioci FV Leiden mutacije.FV Leiden mutation is an important genetic risk factor for venous thromboembolsm (VTE). In this study we have analyzed clinical manifestation and the impact of other genetic and acquired risk factors in 100 patients (95 heterozygous and 5 homozygous) carriers of FV Leiden mutation. Among these patients, 91 experienced VTE, with down limb deep vein thrombosis as the most frequent manifestation. An acquired risk factor was present in 68.6% of women, whereas this was the case in 28.6% of men. FIIG20210A was present in 9.5%, MTHFR 677TT in 8.4% and both mutations in 2.1% of the heterozygous FV Leiden carriers. Our results suggest that knowledge of coexisting factors predisposing to VTE is very important for FV Leiden mutation carriers and may contribute to the prevention of VTE episodes

Fuel Economy Comparative Analysis of Conventional and Ultracapacitors-Based, Parallel Hybrid Electric Powertrains for a Transit Bus

Due to Internal Combustion Engines’ (ICE) significant share in global energy demand, primarily through the transportation sector, great efforts are invested in research for solutions that will increase the fuel economy of ICE-powered vehicles. The main objective of the study presented in this paper has been to perform a comparative study of a conventional and a parallel hybrid electric transit bus employing an ultracapacitors-based energy accumulator. A high-fidelity simulation model of the vehicle has been designed in the AMESim multi-domain system analysis software. The conventional powertrain model has been calibrated using data obtained during an acquisition experiment conducted in realworld traffic conditions on a transit bus. This data also served as the basis for defining the driving cycle on which the numerical analyses will be conducted. A simple, sub-optimal control law has been implemented in the hybrid powertrain simulation model. Also, an advanced energy management law based on Dynamic Programming has been derived to assess the ultimate fuel economy improvement potential of the hybrid solution and to make design decisions. Initial study shows that considerable fuel consumption reduction in excess of 30% could be achieved by implementing a regenerative hybrid system employing an ultracapacitor-based accumulator

A Neural Network-Based Control Algorithm for a Hydraulic Hybrid Powertrain System

Significant research efforts are invested in the quest for solutions that will increase the fuel economy and reduce the environmental impacts of ICE-powered vehicles. The main objective of the study presented in this paper has been to analyze and assess the performance of a control methodology for a parallel hydraulic hybrid powertrain system of a transit bus. A simulation model of the vehicle has been calibrated by analyzing data obtained during an experiment conducted in real-world traffic conditions aboard a Belgrade transit bus. A Dynamic Programming optimization procedure has been applied on the calibrated powertrain model and an optimal configuration that minimizes the fuel consumption has been selected. A Neural Network-based, implementable control algorithm has then been formed through a machine learning process involving data from the optimal, nonimplementable Dynamic Programming-based control. Several Neural Network configurations have been tested to obtain the best fuel economy for the range of conditions encountered during normal transit bus operation. It has been shown that a considerable fuel consumption reduction on the order of 30% could be achieved by implementing such a system and calibration method