Innovative HVAC systems could save fuel or extend EV range

Innovative HVAC systems could save fuel or extend EV range

From SAE International, Author Paul Weissler, published December 2013

©2013 SAE International. All rights reserved.

The concept of zoning the passenger compartment’s climate control system isn’t new. The control system that permits the front passenger to adjust air temperature to a different level from the driver dates back many years. And revisions to the HVAC case that enable a third duct with independent controls for the rear has been a popular addition to many cars. But new approaches to zoning are coming, as part of systems that can reduce cooling and heating output, as well as airflow volume, and direct airflow only to the occupants, specifically the driver if there are no other passengers.

The objective is obvious: improve the fuel economy, as A/C-on operation is now included in one of the U.S. EPA test cycles. But there is an equally important objective: to extend the range of electric vehicles (EVs), which use an electric-drive compressor for A/C and PTC (positive temperature coefficient) heaters, which may be an even greater current draw on EVs. These heaters are also used to supplement conventional heating on hybrids.

Several systems have been proposed. One available for application was introduced by Denso Corp. Two others, an early prototype from Hyundai and an experimental system from General Motors and Delphi, were described at the recent SAE World Congress in Detroit. The Delphi-GM project is focused on passenger thermal comfort with a spot cooling approach to improve efficiency, rather than just climate control of a cabin zone.


To see the complete article, which includes a review of the HVAC systems under development at Denso and Hyundai, please go to: