How does rx8 engine work

Boost a Renesis rotary and everything that went wrong even when naturally aspirated gets exacerbated. The earlier 13B engines are tougher, while the later Renesis ones are more frail, if quieter and more emissions-compliant. So the later RX-8's engine got the car through tougher emissions standards and was quieter and more civilized than its predecessor, the 13B. But that older engine was better made it hailed from a time of the Bubble Era , not unlike the Toyota 2JZ and responds better to big power changes as well as rebuilds.

For now, though, I will have to continue to cast shame at the vile RX-8's engine, hurling curses why such a nice chassis got hobbled by such a weak rotary.

Frankly, I hope if Mazda does another rotary in the future, they take more inspiration from it than the older 13Bs. The A. Nostalgia You Can Taste. Mazda remains committed to working on rotary engine technologies, however. And why might things be different this time around?

For one thing, there are no pistons chugging up and down. Rather, rounded triangular rotors—most often two, but sometimes one or three—spin around a shaft through the hollow barrel. Fuel and air are pumped into the spaces between the rotors' sides and interior walls of the barrel, where they ignite.

The rapid expansion of exploding gases turns the rotors, thus generating power. The rotors fulfill the same task as pistons in a piston engine, but with far fewer moving parts, making a rotary engine lighter and smaller than a piston engine of equivalent displacement. The basic design is a century-old one. Felix Wankel himself was a German engineer who came up with his version of a rotary engine in the s. Being busy with warmongering on behalf of the Nazi party, however, he didn't get the chance to develop his vision too far until , when German automaker NSU invited him to design a prototype.

Paschke's is the engine Mazda would come to own and champion into the 21st century. Thus, the modern Wankel is not quite a Wankel.

Naming concerns aside, Wankel is the most common and successful rotary engine design, and the only one to make it into mass production. Back in the early '60s, NSU and Mazda had a friendly, collaborative competition to sell the first Wankel-powered car as they worked the kinks out of the immature design. NSU was the first to market in , but it destroyed its reputation over the next decade as frequent engine failures sent owners into the shop again and again. The problem was the apex seals—thin strips of metal between the spinning rotors' tips and the rotor housings.

NSU made them out of three layers, which caused irregular wear that made them grenade. Mazda figured out apex seals by making them out of a single layer, and introduced its Wankel in the Cosmo sports-luxury car. In the early 70s, Mazda envisioned an entire lineup of Wankel-powered cars, a dream that was smashed by the oil crisis.

But in a rotary engine, this is accomplished in a completely different way. If you watch carefully, you'll see the offset lobe on the output shaft spinning three times for every complete revolution of the rotor. The heart of a rotary engine is the rotor. This is roughly the equivalent of the pistons in a piston engine. The rotor is mounted on a large circular lobe on the output shaft.

This lobe is offset from the centerline of the shaft and acts like the crank handle on a winch, giving the rotor the leverage it needs to turn the output shaft. As the rotor orbits inside the housing, it pushes the lobe around in tight circles, turning three times for every one revolution of the rotor. As the rotor moves through the housing, the three chambers created by the rotor change size. This size change produces a pumping action.

Let's go through each of the four strokes of the engine looking at one face of the rotor. The intake phase of the cycle starts when the tip of the rotor passes the intake port. At the moment when the intake port is exposed to the chamber, the volume of that chamber is close to its minimum. When the peak of the rotor passes the intake port, that chamber is sealed off and compression begins. By the time the face of the rotor has made it around to the spark plugs , the volume of the chamber is again close to its minimum.

This is when combustion starts. Most rotary engines have two spark plugs. The combustion chamber is long, so the flame would spread too slowly if there were only one plug. The pressure of combustion forces the rotor to move in the direction that makes the chamber grow in volume. The combustion gases continue to expand, moving the rotor and creating power, until the peak of the rotor passes the exhaust port.

Once the peak of the rotor passes the exhaust port, the high-pressure combustion gases are free to flow out the exhaust. As the rotor continues to move, the chamber starts to contract, forcing the remaining exhaust out of the port. By the time the volume of the chamber is nearing its minimum, the peak of the rotor passes the intake port and the whole cycle starts again.

The neat thing about the rotary engine is that each of the three faces of the rotor is always working on one part of the cycle -- in one complete revolution of the rotor, there will be three combustion strokes. But remember, the output shaft spins three times for every complete revolution of the rotor, which means that there is one combustion stroke for each revolution of the output shaft.

The rotary engine has far fewer moving parts than a comparable four-stroke piston engine. A two-rotor rotary engine has three main moving parts: the two rotors and the output shaft.

Even the simplest four-cylinder piston engine has at least 40 moving parts, including pistons, connecting rods, camshaft , valves, valve springs, rockers, timing belt, timing gears and crankshaft.

This minimization of moving parts can translate into better reliability from a rotary engine. This is why some aircraft manufacturers including the maker of Skycar prefer rotary engines to piston engines.

All the parts in a rotary engine spin continuously in one direction, rather than violently changing directions like the pistons in a conventional engine do. Rotary engines are internally balanced with spinning counterweights that are phased to cancel out any vibrations. The power delivery in a rotary engine is also smoother.

Because each combustion event lasts through 90 degrees of the rotor's rotation, and the output shaft spins three revolutions for each revolution of the rotor, each combustion event lasts through degrees of the output shaft's rotation.

This means that a single-rotor engine delivers power for three-quarters of each revolution of the output shaft. Compare this to a single-cylinder piston engine, in which combustion occurs during degrees out of every two revolutions, or only a quarter of each revolution of the crankshaft the output shaft of a piston engine.

Since the rotors spin at one-third the speed of the output shaft, the main moving parts of the engine move slower than the parts in a piston engine. This also helps with reliability. Sign up for our Newsletter!

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