In 1974 Mazda launched the Parkway with rotary engine. The bus was never a success, but it was chic and quirky. Today he is something very special.
The approach wasn't wrong at all. To counteract the increasing environmental pollution caused by the mobility sector, Mazda offered the Bus Parkway with a rotary engine from 1974, two years after its introduction. Thanks to the 2-rotor 13B rotary engine that Mazda had previously used in the RX-3, the Parkway Rotary Super Deluxe 26 far undercuts Japanese emissions regulations. So why is this version of the Parkway only built 44 times? Because the Wankel brought fewer exhaust emissions, but a lot of other problems.,The advantages of the Wankel engine are well known. In the conventional piston engine, a crankshaft converts the reciprocating movement into a rotary movement. A work step that the rotary piston engine can save - as the name suggests, a rotary movement is created with the combustion - with the result that the engine runs with particularly little vibration. The combustion energy is converted directly into drive energy by a largely unbalanced eccentric shaft, which spirals up like a turbine; the whole construction is light and compact. Mazda has been loyal to the drive concept for the longest time, having a car with a Wankel engine in its portfolio until 2012 with the RX-8. But at the Parkway, the rotary piston career was quickly over.
Heavy and thirsty
Two times 654 cubic centimeters of chamber volume, around 180 Newton meters at 4,000 rpm and 135 hp at 6,500 rpm - in this configuration, the bus with space for 26 passengers turns more easily than many a car of its time. Despite a vehicle weight of almost three tons, the Wankel bus can travel at a top speed of up to 125 km/h. A rather short translated four-speed gearbox sorts the propulsion. But there is a reason why there are two fuel tanks with a volume of 70 liters on board: the engine is extremely thirsty. How thirsty exactly, Mazda does not want to reveal. If the optional air conditioning system was ordered when ordering, there is even an additional one-litre piston engine in the rear to operate it. With this equipment, the total weight increases by around 400 kilos and you can imagine how that affects fuel consumption. In addition, the emission behavior should only be treated with caution. Although the nitrogen oxide emissions are about 40 percent lower than those of a piston engine, this is mainly due to the incomplete combustion of the fuel mixture. Because the combustion chamber has an unfavorable shape for complete combustion, more hydrocarbons than nitrogen oxides are ultimately emitted. This is also the reason for the poor efficiency of the drive.,
The Mazda Parkway was designed as a small bus primarily for hotels, schools and small businesses, but due to the high operating costs, hardly any customer from this target group allows themselves the luxury of the Wankel Version. With the introduction of the new Parkway generation in 1982, the drive disappeared from the catalogue. The Parkway continued to roll off the assembly line for another 13 years until production finally ended in 1995. What remains is the curious exception of a bus with the high-revving Wankel engine of a sporty middle-class car.,
Conclusion
The Mazda Parkway Rotary Super Deluxe 26 was the first rotary engine bus. However, the small machine from the RX-3 has a hard time with the heavy vehicle. Today, one of the only 44 examples that were built is on display in the Mazda Museum on Wertachstrasse in Augsburg. Nice, because in addition to the exotic drive, the Parkway also shows the loving Japanese 70s design.
