Years of promises and waiting are over, and the Wankel rotary engine under the hood of a Mazda is finally back on the road. However, don’t expect anything like the RX-8 sports car—the Wankel is in its new use as a generator for the hybrid version of the MX-30 electric vehicle.
Already during the development, which was completed a few years ago, Japanese engineers counted on placing a so-called range extender – a range extender – under the front hood of the MX-30. However, for a long time, this car was only available as an electric car, the attractiveness of which was reduced by a battery with a capacity of only 35.5 kWh.
However, Mazda introduced the MX-30 e-Skyactiv R-EV at the Brussels Motor Show, where the last three letters stand for a range-extender-style rotary engine. It works under the front hood with the generator, it does not deal directly with the wheels, it is electrically powered only.
Mazda is bringing back the Wankel rotary engine, and it will be revealed under the hood of the MX-30 in January
Mazda calls the car the Standard Hybrid. The EREV class – Long Range Electric Vehicle – can also be used, but there is much more gasoline on board than electricity in the battery.
The car’s battery has been halved, to 17.8 kWh, which means that the electric range is up to 85 km. The battery can be charged both with AC and DC, the benefit compared to the purely electric MX-30 is 25 horsepower more, which is 170 hp. The fuel tank has a volume of 50 liters, but the automaker hasn’t revealed how far the car can go with both battery and petrol.
A car in black with a red roof was presented at the Brussels Motor Show, which belonged to the R version. This refers to Mazda’s first passenger car, the R360 Coupe, which also had this color roof. The rotor logo in various places on the interior, for example in the headrests, is also part of this edition.
Triangular piston motor It is the invention of German Felix Wankel and ended up being used in several German cars, the most famous of which is probably the NSU Ro80, which was produced in the years 1967-1977. But it was very unreliable and didn’t last long in production. It is the automaker Mazda that has made it famous all over the world in its RX-7 and RX-8 road models, as well as in its many racing cars.
Mechanically, the Wankel engine is simpler as it lacks a crankshaft and connecting rod mechanism, although the shaft is eccentric even here. There is also no classic valve train; The movement of the piston inside the cylinder opens and closes the intake and exhaust ports differently. A single-rotor engine is not equivalent to the classic single-cylinder engine, because there are three different chambers around the rotor, in which different stages of four-stroke combustion occur at the same time.
However, the drawbacks are in reliability, particularly due to the seals on the rotor terminals. They must be reliably closed, as they separate individual rooms from each other, but at the same time they slide along the walls of the room, which leads to a weakening of their service life due to corrosion. To extend them, as well as to improve the sealing properties, oil is also injected into the chamber along with the fuel.
Particularly reliability and longevity, or the intervals between needing replacement of end seals, which meant complete disassembly of the engine, were always the wankels’ Achilles’ heel. In the case of the MX-30 e-Skyactiv R-EV, the automaker promises better reliability thanks to the fact that the engine will run at a constant speed. Time will tell how it goes
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