The government said Sunday it is investigating reports of engine fires in the Chevrolet Cruze small car and Jeep Wrangler SUV. The fires haven’t caused any injuries but have destroyed at least six vehicles. NHTSA is investigating the 2011 model year Cruze and the 2010 model year Wrangler. The National Highway Traffic Safety Administration has received two reports of fires in the 2011 Cruze. In both cases, owners reported that the fires began while the cars were moving, and in both cases the cars were destroyed. According to complaints filed on NHTSA’s Web site, a driver with a 2011 Cruze Eco was 30 miles into a 43-mile trip last month when smoke started coming out from under the hood. As soon as the driver stopped, flames began shooting out from the car.