Mazda killed off the RX-8 in 2012, and with it, the only Wankel-inspired rotary engine in production. Now, the British publication Autocar reports that Mazda engineers are “very enthusiastically” working on a new rotary engine that will comply with modern emissions requirements.
According to Autocar, Mazda president Masamichi Kogai confirmed that the company still has a “dedicated engineering team focused on rotary engine development” and noted that the engineering staff is working “very enthusiastically” on a Wankel engine that will comply with the same emissions standards of contemporary piston engines.
Rotary engines are internal combustion engines that avoid the inherent vibrations of a conventional piston engine by eliminating most of the moving parts. Instead of a crankshaft connected to reciprocating pistons via connecting rods, the eccentric rotors spin around a central shaft. The outer surfaces of the rotors form the combustion chambers along with the rotor housing.
Modern “Wankel” engines weren’t designed by Felix Wankel at all. They were the second design of rotary engines NSU utilized, known as KKM (Kreiskolbenmotor) engines, and were desinged by Hanns Dieter Paschke in 1957.
In Wankel’s design, known as DKM engines, both the rotors and the rotor housing spin on separate axes, which allowed the engine to turn at remarkable RPM, but also required a complete engine teardown to replace spark plugs. Paschke’s design fixes the rotor housing, resulting in fewer parts, and greater ease of maintenance. According to the German website http://www.der-wankelmotor.de, when Wankel saw Paschke’s design, he commented “
Ihr habt aus meinem Rennpferd einen Ackergaul gemacht! (“You have turned my race horse into a plow mare!”)
NSU was the first company to license the design, and made use of it for several years, but Mazda built its reputation largely on Wankel engines.
Mazda first introduced the engine in the gorgeous Mazda Cosmo in 1967. Mazda built around 1,500 of the futuristically designed Cosmo in two series, between 1967 and 1972. They were powered by two-rotor 0810 and 0813 engines, with up to 125hp.
The second Mazda to feature a rotary engine was the 1968 Mazda Familia Rotary Coupe and Sedan (known outside of Japan as the R100). Instead of raw performance, the Familia Rotary cars skirted Japan’s annual road tax by having a displacement under 1.0-liter, but maintaining the power expected out of a traditional four-cylinder engine of significantly larger size.
In 1971, Mazda introduced the Grand Familia, and the rotary-powered Mazda Savanna in Japan, as a coupe, sedan, and wagon. Around the world, the car was known as the Mazda RX-3, and it sold remarkably well between 1972 and 1978 in the States.
At the same time, Mazda offered the RX-4, a larger car that Mazda suggested was more of a “personal luxury coupe,” in the 1970s vernacular. The RX-4 arrived in 1974 and sold through 1978, when the RX-7 debuted. It featured Mazda’s new 13B rotary engine, with 110 h and 117 lb·ft of torque with US emissions.
Like its Japanese counterparts, early 1970s-era Mazda was paying the bills with compact pickups. Between 1974 and 1978, Mazda offered a version of its successful B-Series pickup called the “REPU”, or Rotary Engine Pick Up. In case you missed what was powering the REPU, you could just look at the back, which had “ROTARY POWER” emblazoned across the tailgate.
Between 1978 and 1992, Mazda built more than 811,000 of its RX-7 sports cars in three different generations, all powered by rotary engines.
In 2001, Mazda reintroduced the rotary engine in the Mazda RX-8, which it sold until emissions requirements made building a specialized sports car with low sales volume too expensive for a bespoke engine.
According to Autocar, “Kogai did not outline a timeline for any return of the RX brand – indeed, he declined to specify precisely why the rotary development team still exists – but it’s feasible that a successor to the RX-8 could appear by 2018, to coincide with the 40th anniversary of the original RX-7.”