Oil Circulation Rate in Ejector Cooling Cycles

Jingwei Zhu, Francesco Botticella, Stefan Elbel

Research output: Contribution to journalConference articlepeer-review


In this study, the influence of compressor speed, ejector motive nozzle needle position and evaporator inlet metering valve opening on the oil circulation rates (OCRs) of an automotive R744 transcritical standard ejector cycle was experimentally investigated. Significantly higher OCR (~10%) was observed at the evaporator inlet of the ejector cycle than at the high pressure side. It has been observed that evaporator OCR was increased with increasing compressor speed. When the motive nozzle needle moved towards the nozzle throat, both compressor discharge flow rate and evaporator OCR were observed to be significantly lowered. As the evaporator inlet metering valve opening was adjusted, the compressor mass flow rate did not vary significantly while the evaporator mass flow rate decreased with decreasing metering valve opening. The evaporator OCR decreased from 6.5% to 2.2% as the metering valve opening varied from 86% to 27%.

Original languageEnglish (US)
JournalSAE Technical Papers
StatePublished - 2018
Event2018 SAE World Congress Experience, WCX 2018 - Detroit, United States
Duration: Apr 10 2018Apr 12 2018

ASJC Scopus subject areas

  • Automotive Engineering
  • Safety, Risk, Reliability and Quality
  • Pollution
  • Industrial and Manufacturing Engineering


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