FISITA World Congress 2023 – Abstract template A Study on the shape and structure for Coolant HUB Seong Bin Jeong*, Hyundai, Republic of Korea1 Nam Ho Park, Wan Je Cho, Tae Hee Kim, Jae Eun Jeong, Hyun Jae Lee KEYWORDS – 2-Rad Coolant Circuit, High Temp Radiator(HTR), Low Temp Radiator(LTR), PE EWP, BATT EWP, 3Way Valve, Reservoir Tank, Integration, 1-CAP & 2-Chamber ABSTRACT Hyundai E-GMP applied two independent cooling circuits that are PE & Batt loop for efficient thermal management. To this end, two RADs, two EWPs, and two reservoir tanks are essential, and it is an extremely complex circuit that requires up to coolant 3 WV for a heat pump. This study is on how to modularize these complex and diverse parts. This part name is “Coolant HUB”. The Coolant HUB can reduce the number of components, costs, reduce weight, secure and arrange an installation space, and solve problems of layout disadvantages and productivity deterioration of a space in a vehicle. This study was the first to review material selection as the Coolant HUB had to directly support the heavy EWP. In addition, we studied the fastening structure between the EWP and the coolant HUB, the sealing structure to prevent leakage, and the optimal design through the DFSS technique to improve the burst pressure. Also the most important part is the study of the internal structure of the Coolant HUB. This topic is divided into three main categories. The first is 1-CAP & 2-chamber structure. When coolant is injected through one CAP, two independent loops must be injected simultaneously. The second is that the two loops must be separated independently during each EWP operation after coolant injection. The third is a method of minimizing thermal interference between the two independent chambers. The mixing of coolant between the two chambers should be minimized, but the air in each loop has to be drained sufficiently through the cap. The results of this study are as follow. The tank material was selected as PP-GF20 to ensure transparency and visibility to check the coolant level. In addition, 6 M4 Insert nuts were applied in consideration of EWP vibration and A/S. The EWP fitting unit secured airtightness by applying double surface pressure o-ring & side pressure o-ring. Finally, we developed and applied the unique shape/technology of 1-cap 2-chamber. This is a unique shape that satisfies various requirements such as coolant injection, heat interference avoidance between two loops, and air bleeding performance. To mention the limitations of this study, due to the limited package space, the reservoir tank's volume could not be increased dramatically, which was limiting in maximizing the air bleeding performance. Based on the current review, it has secured half of the air bleeding performance as output 10% compared to input 20%. In the future, air bleeding performance can also be maximized by forming parallel flow in the reservoir tank. Further research is currently underway on the methodology. The modularization strategy and methodology start with which thermal energy system circuits are applied. If the circuit is simple, modularization will be easy, but if the circuit is complex, modularization will also be difficult. Which means, the modularization strategy is circuit-dependent. This is a modularization study that started with the original thermal energy system circuit of E-GMP, and is the world's first modularization methodology, especially for the 1-cap 2-chmaber structure, which is novel and innovative compared to other works. Through this study, reservoir tanks with two independent loops without heat interference, two EWPs, a 3WV and its connecting hoses, and mount brackets of components were modularized around the coolant HUB. This modularization has also improved the water resistance of the coolant loop, resulting in an increased coolant flow rate, which has even improved the cooling performance. Finally, we reduced the total 8 parts, resulting in a reduction of -1.2kg/-40$, which greatly contributed to profitability. It was first applied to Kia EV6 released in 2021, and it is being applied horizontally through Genesis GV60, KIA NIRO EV, Hyundai IONIQ6 and etc.
Mr. Seong-Bin Jeong, Senior Research Engineer, Hyundai Motor Group