source of hydrocarbon at high speeds, and leakage at low speeds. Using side-porting which enables closing the exhaust port around the top-dead center and reducing intake and exhaust overlap helps improving fuel consumption. Mazda's RX-8 car with the Renesis engine (that was first presented in 1999), met, in 2004, the United States' low emissions vehicle (LEV-II) standard. This was mainly achieved by using side porting: The exhaust ports, which in earlier Mazda rotary engines were located in the rotor housings, were moved to the side of the combustion chamber. This approach allowed Mazda to eliminate overlap between intake and exhaust port openings, while simultaneously increasing the exhaust port area. This design improved the combustion stability in the low-speed and light load range. The HC emissions from the side exhaust port rotary engine are 35–50% less than those from the peripheral exhaust port Wankel engine. Peripheral ported rotary engines have a better mean effective pressure, especially at high rpm and with a rectangular-shaped intake port. However, the RX-8 was not improved to meet Euro 5 emission regulations and was discontinued in 2012. The new Mazda 8C of the Mazda MX-30 R-EV meets the Euro 6d-ISC-FCM emissions standard. Laser ignition Laser ignition was first proposed in 2011, but first studies of laser ignition were only conducted in 2021. It is assumed that laser ignition of lean fuel mixtures in Wankel engines could improve fuel consumption and exhaust gas behavior. In a 2021 study, a Wankel model engine was tested with laser ignition and various different gaseous and liquid fuels. Laser ignition leads to a faster center of combustion development, thus improving combustion speed, and leading to a reduction in NOx emissions. The laser pulse energy required for proper ignition is "reasonable", in the low single-digit mJ-range. A significant modification of the Wankel engine is not required for laser ignition. Compression-ignition Wankel Research has been undertaken into rotary compression ignition engines. The basic design parameters of the Wankel engine preclude obtaining a compression ratio sufficient for Diesel operation in a practical engine. The Rolls-Royce and Yanmar compression-ignition approach was to use a two-stage unit (see figure 14.), with one rotor acting as compressor, while combustion takes place in the other. Both engines were not functional. Multifuel Wankel engine A different approach from a compression ignition (Diesel) Wankel engine is a non-CI, multifuel Wankel engine that is capable of operating on a huge variety