Ejector having throttle variable nozzle and ejector cycle using the same

摘要

An ejector includes a nozzle and a needle valve formed in a tapered shape. The needle valve controls a throttle opening degree of the nozzle from a minimum degree to a maximum degree while an end section of the needle valve is positioned on a downstream side with respect to a throat section of the nozzle. Besides, a cross-sectional area of a nozzle diffuser is formed to be substantially constant, downstream of the throat section. Thus, a cross-sectional area of a substantial refrigerant passage defined by an inner surface of the nozzle and the needle valve is gradually widened in accordance with the tapered shape of the needle valve. Therefore, pressure loss accompanied with a rapid expanding can be suppressed. As a result, the throttle opening degree of the nozzle can be controlled while improving nozzle efficiency and ejector efficiency.