Mazda later abandoned the Wankel in most of their automotive designs, continuing to use the engine in their sports car range only, producing the RX-7 until August 2002. The company normally used two-rotor designs. A more advanced twin-turbo three-rotor engine was fitted in the 1991 Eunos Cosmo sports car. In 2003, Mazda introduced the Renesis engine fitted in the RX-8. The Renesis engine relocated the ports for exhaust from the periphery of the rotary housing to the sides, allowing for larger overall ports, better airflow, and further power gains. Some early Wankel engines also had side exhaust ports, the concept being abandoned because of carbon buildup in ports and the sides of the rotor. The Renesis engine solved the problem by using a keystone scraper side seal, and approached the thermal distortion difficulties by adding some parts made of ceramics. The Renesis is capable of with improved fuel economy, reliability, and lower emissions than previous Mazda rotary engines, all from a nominal 1.3-L displacement, but this was not enough to meet more stringent emissions standards. Mazda ended production of their Wankel engine in 2012 after the engine failed to meet the more stringent Euro 5 emission standards, leaving no automotive company selling a Wankel-powered vehicle. The company is continuing development of the next generation of Wankel engines, the SkyActiv-R. Mazda states that the SkyActiv-R solves the three key issues with previous rotary engines: fuel economy, emissions, and reliability. Mazda and Toyota announced they combined to produce a range extending rotary engine for vehicles.