Prescribed Temperature Profile Research Articles

Nonlinear-Control Strategy for Advanced Vehicle Thermal-Management Systems

Advanced thermal-management systems for internal combustion engines can improve coolant-temperature regulation and servomotor power consumption by better regulating the combustion process with multiple computer-controlled electromechanical components. The traditional thermostat valve, coolant pump, and clutch-driven radiator fan are upgraded with servomotor actuators. When the system components function harmoniously, desired thermal conditions can be accomplished in a power-efficient manner. In this paper, a comprehensive nonlinear-control architecture is proposed for transient-temperature tracking. An experimental system has been fabricated and assembled which features a variable-position smart valve, variable-speed electric water pump, variable-speed electric radiator fan, engine block, and various sensors. In the configured system, the steam-based heat exchanger emulates the heat generated by the engine's combustion process. Representative numerical and experimental results are discussed to demonstrate the functionality of the thermal-management system in accurately tracking the prescribed temperature profiles and minimizing electrical power consumption.

Radiative transfer in LTE air plasmas for temperatures up to [formula omitted

Radiative transfer in local thermodynamic and chemical equilibrium N 2–O 2 plasmas is analyzed in this study using a line-by-line approach. The contributions of line absorption by atoms, ions and of continuous absorption by atoms, ions and molecules to the absorption coefficient of heated air are calculated. These data combined to our previous work on the contribution of molecular electronic systems to heated air radiation (J. Quant. Spectrosc. Radiat. Transfer 72 (2002) 503) lead to a reliable and exhaustive spectroscopic data base for radiative transfer in air plasmas and for temperatures up to 15,000 K . Line-by-line radiative transfer calculations are carried out for a simple planar geometry with prescribed temperature profiles. The spectral distribution of radiative fluxes and volumetric powers is analyzed and the relative contributions of continuum and line radiation are discussed.