The federal government ended a 20-month investigation into Hyundai Accent air-bag systems that have been linked to the deaths of 10 children. The National Highway Traffic Safety Administration did not rule on the presence or absence of a safety defect when the bags are deployed but said there was insufficient evidence to warrant continued investigation. Almost 250,000 Accent models were equipped with the systems being investigated. The agency's report said at least eight of the children killed were probably were too close to the air bag when it deployed--factors that could not be controlled by the auto maker. Officials at Fountain Valley-based Hyundai Motor America declined to comment, saying they needed more time to review the report. The investigation was opened in July 1999 and covered 1995 through 1999 model-year Accents. Hyundai redesigned the air bags for the 2000 model year.