International Journal of Automotive Research, Vol. 9, No.1, (2019), 2868-2875 * Ashraf Elfasakhany Email Address: ashr12000@yahoo.com 10.22068/ijae.9.1.2868 Adjustable throat-area expansion valves used in automotive air conditioning systems: A mini review Ashraf Elfasakhany 1 1 Department of Mechanical Engineering, Faculty of Engineering, Taif University, Box 888, Taif, KSA ARTICLE INFO A B S T R A C T Article history: Received : 2 Oct 2018 Accepted: 18 Mar 2019 Published: Adjustable throat-area expansion valves (ATAEV) are functioned as area regulator control units. In literatures, there are many expansion valves normally used in automotive air-conditioning systems, as regulator and electrical type valves. Nevertheless, a review study for such issue has not been introduced, according to the best of author knowledge. The present paper presents a review study for expansion valves used in air conditioning of automobiles. Different types of expansion valves are discussed including the working principles and the limitation of their working conditions. Keywords: Automobiles; Air conditioning; Review Electronic expansion valve 1 Introduction Adjustable throat-area expansion valves (ATAEV) are essential part of automotive air conditioning system. Fig. 1 shows the components of automotive air conditioning system, while Fig. 2. Shows a schematic view of the adjustable throat-area expansion valve and it working principle. In fact, there are many area regulator control units, as expansion valves and capillary tubes. Expansion valves (EVs), as regulator and electrical type valves, are normally used for adjustable throat-area in air conditioning systems. The electronic expansion valves, driven by a stepper controlled by a pulse signal generator, have been widely applied in refrigeration systems. The stepper is normally afford definite adjustments to valve control, for example, opening diameter of 1.8 millimeter will reach a exactness up to 0.002 mm2 of throat space per one pulse signal. Due to precise and quick management for refrigerant flow, the refrigeration systems exploitation EEVs have far more benefits than those exploitation conventional enlargement devices in terms of refrigerant supply stability and superheat control reduction. The study by Aprea and Mastrullo [1] showed that EEV has a far better management for superheat underneath steady- state conditions. As a result, EEV will execute a lot of robust improved management strategy and contains a more steady operation [2]. Moreover, the EEV systems have far better stability as compared with the capillary tubes [3]. The robustness of EEVs may be attributed to specific flow metering or precise gap adjustment, while other expansion valves aren't similar to EEVs. The impact of the valve parameters was investigated by imposing a step increase of the suction line pressure and simulating the response of the evaporator superheat over time. This approach allowed comparison of the steady state and transient behavior of superheat with totally different valve styles. This study presents a review work of adjustable throat-area expansion valves (ATAEV) applied in automotive industries. This study is one of our sequences studies in automotive industries, see e.g., [4–34] and International Journal of Automotive Engineering Journal Homepage: ijae.iust.ac.ir ISSN: 2008-9899 [ DOI: 10.22068/ijae.9.1.2868 ] [ Downloaded from www.iust.ac.ir on 2021-12-16 ] 1 / 8