Can Mazda find a way out of the hybrid field for rotor engines?

Text/Qin Ming

In the 59th 24 Hours of Le Mans in 1991, the Mazda 787B equipped with a rotor engine successfully won the championship against strong opponents such as Porsche, Mercedes-Benz and BMW. Rotor engines have also become famous and are touted by many fans around the world, Mazda as the most avid fan of rotor engines, since spending a lot of money to buy this technology, Mazda began to develop and produce rotor engines alone, but also successfully transitioned experimental production to commercial production, installed on the RX-7 sports car.

Unfortunately, the natural structural characteristics of the rotor engine make its emissions, fuel consumption, and wear problems very serious, and have not been able to effectively solve. In 2012, the last model on the market equipped with a rotor engine, mazda RX-8, was officially discontinued, and mazda began to sell cars and maintain engines.

The working principle of the rotor engine

The basic structure of the rotor engine is to place a triangular-like rotor in an elliptical space, and the three faces of the rotor can divide the elliptical space into three independent combustion chambers.

Because the rotor is eccentric, the volume of these separate combustion chambers will constantly change during operation, using the changing characteristics of confined space to achieve the intake, compression, ignition and exhaust processes required for four-stroke operation.

The rotor of the rotor engine turns a circle of ignition 3 times, that is, 3 times of work is done, and the rotor rotates a circle of eccentric shafts to turn 3 times, so it is equivalent to a spin of eccentric shafts, do a work, compared with a four-stroke engine, to complete four stroke crankshafts need to turn twice, crankshaft turns two turns to do a work, so the rotor engine displacement is often twice that of the piston engine of the same level.

Why can't it be admired in the field of traditional fuels?

In fact, in addition to Mazda, Mercedes-Benz, Volkswagen and General Motors have all been tinkering with rotor engines, and some have also produced mass production models, but now almost no one plays. It is mainly due to the following disadvantages: fuel consumption, emissions, cost and durability.

High frequency of work must be provided with fuel at a high frequency, which is the premise of high fuel consumption of the rotor engine; the rotor engine is difficult to control the high compression ratio, resulting in its fuel thermal efficiency is very low, invisibly increasing fuel consumption, the rotor engine does not have an independent intelligent lubrication system to inject oil into the cylinder for lubrication, then the oil will definitely participate in the combustion and lead to emissions that are not up to standard.

Rotor engine sealing problem has not been effectively solved, easy to produce temperature difference leading to loose sealing, although the rotor engine structure is simple but the degree of integration is very high, maintenance is too troublesome and the average person can not do, "a hundred kilometers of an engine", "twelve cylinder maintenance", is not a hole in the air. Rotor engines are not guaranteed for a long time in uneven temperature and high-efficiency working environments, and they are not operating well for a long time, resulting in premature wear.

Although many options have been improved, such as porcelainizing the cylinder wall (ceramicizing the cylinder wall surface to reduce friction and be more resistant to high temperatures without lubrication), screening the sealing material with three top corners, etc., there has been no better breakthrough.

Therefore, although the rotor engine can squeeze out stronger power with a small displacement, but the fuel economy and emissions are difficult to control, and the piston engine with hybrid and turbocharged than the rotor engine is more suitable for the current trend, especially with the development of new energy models, many car companies have begun to shift the focus to battery and hybrid system research and development, consumers for the new energy model gradually accept and favor, so that Mazda also had to start to develop in the direction of new energy.

What are the highlights of the turn-to-combat hybrid?

Although the rotor engine has obvious shortcomings, it also has its own advantages, otherwise Mazda will not be on it, spending decades of painstaking efforts, Mazda also saw that the rotor engine has the advantages of small size, light weight, and space saving, so Mazda chose to transfer the rotor engine to the hybrid system as a generator.

Rotor engine due to natural characteristics, small body, high liter power, light weight, the efficiency of the rotor engine to provide power generation is definitely higher than that of ordinary piston engines, very suitable for use as a range extender. At the same time, the rotor engine has the advantages of lightweight and downsizing, coupled with the front and mid-mounted layout, so that the model it is equipped with brisk and precise driving characteristics.

On the MX-30, the rotor engine is used as a range extender in the hybrid system, that is to say, on the MX-30, the main job of the rotor engine is "charging", and the high torque of the motor and the high power of the rotor are complementary, which seems to be a more tacit combination.

However, for Mazda, the use of rotor engines on the MX-30 seems to be a helpless move, it is reasonable to say that such a black technology engine should have a more important use, used in the MX-30 such a relatively small size SUV, a bit of oversized feeling, but also shows that Mazda may not be fully in place for the power output control of the rotor engine, although Mazda has been conducting many years of rotor engine research, but in the increasingly demanding emission standards in the environment, The technical challenges faced by today's rotor engines are completely different from those of previous rotor engines.

Write at the end:

The rotor engine has actually become a kind of totem of Mazda, perhaps with the change of the times, Mazda can not reproduce the glory of the rotor engine, but perhaps Mazda can open up a new development direction in the future, no longer bound by the traditional fuel mode Ofmadam may have a better future, if the rotor engine is really used as a range extender in the future, I believe that Mazda will also be unwilling, after all, it has been hard work for decades in exchange for such results, and no one will be willing to accept it. Personally, the range increase is only the first step, and the drive machine in the hybrid system may be where Mazda wants to realize the value of the rotor engine