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Modeling and fuzzy control of the engine coolant conditioning system in an IC engine test bed
Seyed Saeid Mohtasebi,Farzad A. Shirazi,Ahmad Javaheri,Ghodrat Hamze Nava 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.11
Mechanical and thermodynamical performance of internal combustion engines is significantly affected by the engine working temperature. In an engine test bed, the internal combustion engines are tested in different operating conditions using a dynamometer. It is required that the engine temperature be controlled precisely, particularly in transient states. This precise control can be achieved by an engine coolant conditioning system mainly consisting of a heat exchanger, a control valve, and a controller. In this study, constitutive equations of the system are derived first. These differential equations show the second- order nonlinear time-varying dynamics of the system. The model is validated with the experimental data providing satisfactory results. After presenting the dynamic equations of the system, a fuzzy controller is designed based on our prior knowledge of the system. The fuzzy rules and the membership functions are derived by a trial and error and heuristic method. Because of the nonlinear nature of the system the fuzzy rules are set to satisfy the requirements of the temperature control for different operating conditions of the engine. The performance of the fuzzy controller is compared with a PI one for different transient conditions. The results of the simulation show the better performance of the fuzzy controller. The main advantages of the fuzzy controller are the shorter settling time, smaller overshoot, and improved performance especially in the transient states of the system.
Soheila Ghasemi,Marzieh Owrang,Farzad Javaheri,Fatemeh Farjadian 한국고분자학회 2022 Macromolecular Research Vol.30 No.5
Poly(N-isopropylacrylamide) (PNIPAAm) hydrogel as a temperatureresponsive polymer was prepared through controlled process using reversible addition fragmentation chain transfer (RAFT) polymerization. The hydrogel was then amino modified using a biocompatible polyamine i.e. spermine and next the antitumor cisplatin drug was conjugated to the modified hydrogel via pH-sensitive spermine linkage. This system had a pH dependency and temperature sensitivity at lower critical solution temperature (LCST). Cisplatin potentially is liberated from the carrier in the acidic environment. However, the release of cisplatin from this polymeric system is increased considerably around the transition temperature of the polymer. The drug release manner of the prepared hydrogel was determined at two pH values (5.5 and 7.4) and three temperatures (37, 40 and 42℃) at different time intervals. The in vitro toxicity assessment was conducted on MCF-7 cell line which showed the system efficiency in killing breast cancer cells.