At the 24 Hours of Le Mans held on June 23, 1991, the Mazda 787B car equipped with a rotary engine won the championship by a huge margin of two laps ahead of second place, making the rotary engine shine. However, the following year, the Mazda 787B car was disqualified, and legend has it that it was banned because the rotary engine was too "black technology". It's like disqualifying Usain Bolt from the 100m because he has a strong advantage in winning the 100m, which is incredible.

Personally, I really appreciate the rotary engine because it basically does the work of the Force driving the crankshaft. When Wankel invented the rotary engine in 1956 and was first installed on the car in 1964, it was wildly robbed of its R&D and production rights by major automobile manufacturers at that time, and was even once thought to replace the traditional reciprocating piston engine. Since it was an emerging technology that required a lot of capital investment, major manufacturers weighed the pros and cons and stopped developing it, but only Mazda persevered and made a name for itself at the 24 Hours of Le Mans in 1992.

The unique talent of the rotary engine is its birthright for the racetrack, as evidenced by its performance in the 1992 Le Mans 24-hour endurance race. How does it achieve this? What are its advantages?

As you know, not long ago at the Tokyo Motor Show, Mercedes-Benz AMG Project ONE, has an F1 racing engine, in order to reach 12000 rpm, 1.6L is made into a V-shaped 6 cylinder to overcome nearly 400G acceleration, and the acceleration that the F1 engine piston needs to overcome is at least about 600G, because the rotation of the crankshaft is reciprocated by the piston in the cylinder to do linear motion, and then converted through the crank connecting rod mechanism. This is the hard injury of reciprocating piston engines, especially L-shaped engines, the top dead center of combustion expansion pressure is the largest, and the transmission force of the connecting rod is basically perpendicular to the tangential direction of the crankshaft. It's going to be a big challenge. But for rotary engines, these are pediatrics. The rotary engine is the same as the conventional reciprocating four-stroke engine, and it also needs to complete the four cycles of suction, compression, work and exhaust, but the difference is that the crankshaft of the conventional reciprocating piston engine rotates for two weeks to complete these four working cycles. The rotor of the rotor engine rotates for a week to complete these four working cycles, the work efficiency is increased by 1 times, and within the week of rotor rotation, the cylinder that is divided into 3 independent spaces by the top angle of the rotor completes these four working cycles at the same time, which is quite perfect, and the piston is pushed to do the rotation motion without interruption, which is exactly what the racing car needs.

The combustion gas pushes the rotor to make eccentric rotational motion, and the rotor applies rotational torque to the eccentric shaft, directly driving the eccentric shaft to rotate and do work. Because it is the rotational torque that does work, there is no need to overcome any inertial force, and the engine speed can be greatly improved. In addition, when the triangular rotor rotates, the inner gear ring centered on the center of the triangular rotor meshes with the fixed gear centered on the center of the output shaft. The gear is fixed on the cylinder body and does not rotate. The gear ratio of the inner gear ring to the gear is 3:2. Since the two are internally meshed, and the inner gear ring always rotates with the contact point between the two (such as the red point) as the center, the rotation radius is 3 times that of the inner gear. Due to this unique motion relationship, the speed of the output shaft will be 3 times the rotation speed of the rotor. For example, when the crankshaft speed reaches 15,000 rpm, the rotation speed of the triangular rotor only needs to reach 5,000 rpm. The crankshaft speed of the reciprocating piston engine must reach 15,000 rpm, and the piston must reciprocate up and down 30,000 times within 1 minute. The advantages of both are self-evident. In addition, at high engine speeds of more than 1W, the opening and closing of the valves of a conventional reciprocating piston F1 racing engine is driven by a high-pressure nitrogen pressure tank, because conventional steel springs are completely incapable of doing this job. However, for a rotary engine, this is not a problem at all, because a rotary engine does not have an intake system such as valves, camshafts, rocker arms, and timing systems.

From this point can also be illustrated, due to the absence of valves, camshafts and other motion noise, NVH compared with the traditional engine will be much superior, the rotary engine structure is very compact, such as the rotary engine, the single-rotor engine is only about 1 foot in length, width and height, which is convenient for the whole vehicle layout, and the engine of the same displacement is reduced by at least 1/3 of the weight. So the rotary engine is made for the track and not out of thin air, and it is said that the German company Rotary Supercars will launch an eight-rotor four-turbo supercar, and this supercar accelerates from 0 to 100KM/h in just 0.9 seconds. In the blink of an eye, this sports car has completed 100 kilometers of acceleration, and in front of it supercars such as Bugatti and Lamborghini are simply pediatric.

While rotary engines have many advantages, they also have disadvantages that cannot be ignored, which is why there is no mass civilian use today:

1: Insufficient combustion, because the intake and exhaust of the rotary engine is not driven by valves, but by the rotation of the rotor to open and close the intake and exhaust valves, there is no timing VVT to accurately control the air-fuel ratio, and the mixture will be incompletely combusted, which is more fatal to the current increasingly stringent emission regulations.

2: Fuel consumption is very high. The fuel consumption of the 1.3L or so rotary engine on the car is about 12L/100 kilometers, which I want to avenge the rotary engine, because the rotary engine triangle rotor rotates in the process of doing work, that is, the rotor rotates for one week, the three cylinders are ignited three times, and the fuel is injected three times, but the reciprocating piston engine rotates 2 times before the oil is sprayed once and ignited once. Of course, the fuel consumption is higher than that of the reciprocating piston engine of the same displacement, so many countries tax the displacement of the rotary engine by multiplying the nominal displacement by 2.

3: Burning oil: In fact, for rotary engines, burning oil is unavoidable. Because the high-speed rotation of the triangular rotor requires extremely fast cooling and lubrication, the oil plays such a role, there is a small hole in the cylinder block that is specially injected with oil, and the oil is injected to the inner wall of the rotor, and the top angle sealing strip of the triangular rotor is evenly applied to the inner wall of the rotor. When one of the cylinders is ignited, the oil is naturally burned, and the rotor rotates and ignites three times a week, so the oil burns quickly.

4: Serious wear and short life of parts: Because there is only one warp seal in the adjacent cavity of the triangle rotor engine, the warp seal is always in line contact with the cylinder block, and the position of the warp seal and the cylinder block is always changing, so the three combustion chambers are not completely isolated, and the warp seal wears out quickly. Moreover, the ignition position of the spark plug of the cylinder block is always in the same place, and the heating of the cylinder block is uneven, and the cylinder block is prone to slight deformation.

Although not as well-known as the reciprocating engine, it is precisely because of the niche that he has a more graceful and luxurious temperament and demeanor, and the rotary engine is more like a scientist who is obsessed with technology, and has been climbing the peak of technology. The research of rotary engines has given rise to many emerging technologies, and the fact that rotary engines have been more widely used in aerospace than reciprocating piston engines also proves the research and development potential of rotary engines. It is believed that with the continuous development of technology and the continuous application and innovation of new materials, the spring of rotary engine will be just around the corner.