Test Technologies Contributing to Electrification - 5. Test Technology for Thermal Management System Achieving Both Low Electricity Cost and High ComfortFig. 3 p–h diagram3.1 Development of data processing system3. Solutions3.2 Test facilities reproducing temperature 58Fig. 5 Air-conditioner cycle bench test equipmentFig. 4 Real-time data processing systemenvironmentenvironment, which is an attractive feature of EVs. The EV cooling system operates not only while driving, but also during charging, which is essential for EVs. The battery temperature varies with the charge output and driving conditions applied prior to charging, and this can affect battery performance. Therefore, it is necessary to reproduce not only the outside air temperature and driving conditions but also the temperature environment of the systems associated with the battery.The refrigerant used as cooling energy transforms into gas, liquid, and gas–liquid mixtures. The temperature and pressure are measured at multiple points to determine the physical properties of the refrigerant in the corresponding state to monitor whether the refrigerant is in the proper condition. The coupled temperature and flow rate of the cooling water are acquired at multiple points to determine whether the desired cooling is achieved.Based on the data obtained from these measurement points, further data are obtained through tests in which the number of conditions is defined as the number of temperature levels multiplied by the number of driving modes. A large amount of data processing is required, and such data cannot be analyzed using conventional post-test processing. Therefore, we developed a real-time processing system that can perform these time-consuming evaluations.Real-time measurements of temperature and pressure are not sufficient for determining the state of the refrigerant that provides cooling energy. The presence of an appropriate gas or liquid state must be confirmed by referring to the physical properties of the refrigerant that corresponds to temperature and pressure. Therefore, it is necessary to draw a pressure–enthalpy (p–h) diagram (see Fig. 3).Thus, we developed a system to calculate the physical properties in real time based on the data measured in a time series. In this system, the measurement data are captured in real time and listed as time-series data. p–h diagrams were also drawn in real time to visually grasp the state of the refrigerant. This system reduces the data-processing time, as indicated in Fig. 4. The test facilities used to investigate the cooling circuits and interior comfort are equipped with an air-conditioner cycle bench tester and an actual vehicle, which are measured with a chassis dynamometer placed in an all-weather environment. The environment reproduces weather conditions ranging from low and high temperatures to rainfall and snowfall.The air-conditioner cycle bench test equipment is used to evaluate the system performance prior to building a prototype vehicle. The equipment evaluates the characteristics of the components related to the cooling circuit, from air-conditioner-related components to cooling components (Fig. 5).The An all-weather environmental chassis dynamometer is used in the tests with actual vehicles (Figs. 6 and 7). The reproduces test equipment the expected temperature environment in an actual vehicle from low to high temperature. It is possible to verify whether the heat balance with the HVAC, compressor, and other cooling circuits is on target. Tests can be performed by modifying the component characteristics and control conditions as required.
元のページ ../index.html#63