investigatiton of Airflow Characteristics in Simplified Vehicle Cabin During Fresh Air Rate Control Using Stereo PIV Visualization

Kosuke Onishi･Takuji Nakashima･Kazuki Ito･Hidemi Mutsuda (Hiroshima University)

Reducing air‑conditioning energy consumption is critical for electric vehicles. With the advent of autonomous driving, the vehicle cabin is increasingly envisioned as a living space, making occupant comfort as important as energy efficiency. In this study, a simplified vehicle cabin model was used to investigate an intermediate AC mode that mixes fresh and recirculated air. The influence of this mode on the cabin airflow field was examined experimentally through stereo PIV visualization. Flow‑field control strategies were evaluated with the aim of improving thermal comfort while minimizing AC energy use.

Investigation of Vehicle Cabin Airflow Characteristics for Pre-Conditioning Efficiency Enhancement Using CFD and Proper Orthogonal Decomposition

Kazuki Ito･Takuji Nakashima･Kosuke Onishi･Hidemi Mutsuda (Hiroshima University)

In the vehicle cabin, the airflow from the HVAC system forms a complex flow field due to interactions such as impingement on interior components and the characteristics of the air-delivery configuration. In this study, CFD simulations of the vehicle cabin flow field were conducted under multiple conditions by varying the outlet direction and ventilation mode to achieve efficient cabin ventilation. Furthermore, Proper Orthogonal Decomposition (POD) was applied to extract characteristic flow modes, from which effective control strategies for improving HVAC airflow efficiency were investigated.

Measurement and Analysis of Automotive Cabin Thermal Insulation Characteristics and Elucidation of Heat-Gain/Heat-Release Behavior

Ying SUN･Haruki NAKAMAE (Molten Corporation)･Shigeru OGAWA (Ogawa Fluid Research Institute)･Takahiro TSUTSUMOTO･Tsuyoshi SUGIHARA (Hiroshima Industrial Promotion Organization)

Improvement of the driving range of electric vehicles (EVs) requires not only advances in battery systems but also the reduction of energy losses associated with cabin climate control. In the present study, heat-flux measurements and thermal analyses were performed using both an actual EV and a controlled experimental apparatus in order to obtain a detailed understanding of the thermal insulation characteristics of EV cabins. Particular attention was directed toward the heat-gain and heat-release behavior within multilayer cabin-wall structures. The internal temperature distribution and the influence of external airflow on heat transfer through the wall were examined, and the resulting findings are reported herein.

Development of Personalized Thermoregulation Model

Rikiya Okabe (Mazda)･Akira Togii (Hiroshima University)･Hideaki Nagano･Masanori Shukuya (Tokyo City University)

To enhance individual comfort in vehicle cabins, blower levels and outlet temperatures should be automatically adjusted for each occupant. This requires a human thermoregulation model and a climate control system based on that model. We developed a personalization method for the human thermoregulation model and demonstrate its application.

A Study On Optimizing Automotive Air Conditioning For Cabin Comfort

Jun Suzuki･Masaharu Marumoto･Koki Kawakami･Akane Kawakami･Akira Togii (Mazda)

In order to improve the comfort of automotive air conditioning and reduce energy consumption, we developed a CFD surrogate model that quickly calculates convective airflow in the cabin. Using parameter studies and optimization, we clarified how air conditioning blowing conditions (air volume, distribution, etc.) affect the temperature field and velocity field distribution near different parts of the human body.