Hyundai/Kia Fuel Economy Background
Fuel economy is measured under controlled conditions in a laboratory, using a device called a dynamometer. The dynamometer simulates a vehicle driving on the road. The amount of fuel burned per mile (gallons per mile) is measured and then converted into miles per gallon for the fuel economy label.
All manufacturers test prototype vehicles, calculate the fuel economy information and submit the data to the U.S. Environmental Protection Agency (EPA) for review. EPA issues Certificates of Conformity based on the data submitted by manufacturers, and runs confirmatory tests on a percentage of vehicles. These confirmatory tests are run on production vehicles. There are typically variances between the prototype test information originally submitted to EPA and the later production tests.
EPA Coastdown Testing
In order to measure and calculate fuel economy, a manufacturer must first assess each vehicle’s “coastdown” value. This value is determined through a series of tests run by the manufacturer. Earlier this year, EPA informed Hyundai and Kia’s technical center that it had questions about how Hyundai and Kia had determined the coastdown values for its vehicles. EPA’s independent testing had resulted in coastdown values different than those reported by Hyundai and Kia.
Hyundai/Kia Cooperative Test Program with EPA
The companies engaged in a testing program with EPA to determine the source of the test result differences. The companies’ technical team found certain discrepancies in the way in which the coastdown testing was conducted. EPA also found that the companies’ interpretation of certain aspects of the procedures differed from EPA’s understanding of how the tests are generally conducted.
Hyundai/Kia Future Testing
Hyundai and Kia have agreed to conduct all future testing in the manner EPA has communicated to the companies and to rectify certain procedural errors found during the test program. Hyundai and Kia are committed to working with EPA to ensure that all future testing meets EPA’s expectations.