Improve the Passenger Thermal Comfort Inside Car Cabin at Various Seat Location

In today’s competitive automotive industry with its rapid pace of innovation, HVAC engineers continually think about customer convenience and their comfort requirements. ‘Multi zone HVAC system’ is one of the features that proposes to satisfy the customers’ need for individualized comfort settings for each passenger seated in different parts of a vehicle cabin. In many instances, passengers in a car have different preferences for air temperature setting based on their sitting locations. This situation sometimes arises due to difference in the intensity of solar radiation entering inside vehicle cabin from windscreen and front/side glasses. This happens due to relative position of the sun and the direction which the car is facing. In the current single zone automatic HVAC system, the user can only set one common temperature and air flow rate for the entire vehicle cabin. There is no provision for each passenger seat to have a unique temperature and air flow setting according to the individual passenger’s comfort requirement. Some vehicles today have ‘dual zone’ or quadra zone systems that allow passengers to select different temperature settings for different locations within the cabin. Here, temperature and air velocities are controlled by using two HVAC units, one unit located at front side below the dashboard and other located at centre console. However, due to the additional components these systems have high cost and are limited to luxury segment. There is therefore an opportunity for inventive solutions for maintaining individual temperature zones at each seating location, while employing a single HVAC unit. This paper illustrates the proposed innovation which is to develop a mobile air conditioning system that provides hot/cold air to all passengers as per their unique comfort requirements along with independent temperature control using a HVAC unit with single blower, single evaporator and single heater. This we have achieved by modifying a single zone unit, by adding partitions in the HVAC unit thereby creating four separate compartments in a single HVAC unit. Separate flaps are mounted in each compartment in order to control air velocities and temperature as per requirements at respective seating location. Additional 6 servomotors are used to maintain position of these flaps for mixing of hot and cold air inside the HVAC unit. A separate control panel is provided for rear passengers. An additional flap is provided in the rear console to divert air stream in leg mode for rear passengers.