HVAC System Bench Test Analysis for TXV Tuning 2018-01-0070

In today’s automotive industry, the A/C (Air-conditioning) system is emerging into a high level of technological growth to provide quick cooling, warm up and maintaining the air quality of the cabin during all-weather conditions. In HVAC system, TXV plays vital role by separating high side to low side of vapor compression refrigeration system. It also regulates the amount of refrigerant flow to the evaporator based on A/C system load. The HVAC system bench laboratory conducts the test at different system load conditions to evaluate the outputs from tests during initial development stage to select the right TXV in terms of capacity and Superheat set point for a given system. This process is critical in HVAC developmental activity, since mule cars will be equipped with selected TXV for initial assessment of the system performance.

The TXV tuning is conducted in system bench lab using defined test load cases which is developed using combination of given input boundary conditions and tests were conducted based on that. In this paper, major focus is laid on understanding potential importance of each system parameter, identify bench test boundary conditions that are critical for TXV set point decision making and understand internal stakeholder’s requirement. The whole process started with conducting personal interviews with internal stakeholders and suppliers to collect raw voices of customers. The DFSS tools were used to capture internal customer voices and translate into technical measures to provide insight of the data required for TXV selection. Tools used such as voice affinity, HOQ, Pugh Matrix, and Function tree diagram etc. The raw voices from interviews are translated into most important voice and mapped with current process using HOQ approach. The main purpose of house of quality is to derive the measurable targets to meet customer requirement. This study helps us to reduce the number of physical testing by approx. 35% without affecting TXV selection process and use objective approach to study system parameters.