Mazda Brought Back The Rotary Engine!

*Common Question!* Why would a range extender (engine + generator) need to operate at different RPM? Realistically, the option for a single RPM is there, and as stated in the video, there's likely an RPM that the engine spends the vast majority of its time at. There are reasons, however, why you might want to occasionally run at different RPM. For example: 1) Engine startup. This engine makes peak power at 4500 RPM. If peak power is needed to recharge the battery, you probably don't want to go straight there on a cold engine. 2) Battery charge rate. Batteries are able to charge faster at lower SOC (state of charge), vs higher SOC. This could mean at low battery, the engine output would be greater, and at higher battery SOC, the engine output drops because the max charge rate of the battery is lower. 3) If the engine is capable of high output, it likely exceeds the max charge rate of the battery. For example, the battery (relatively small vs dedicated EVs) is capable of 36 kW fast charging (it's a small battery so this is a normal number, despite sounding low). The rotary engine has a max output of 74 HP (55 kW), thus exceeding the max charge rate, so there are likely times where it runs at lower loads, and times it runs at higher loads, depending on the battery's SOC. So why does the rotary have more power than needed? At times, it is used to not only power the generator, but also to send more power to the driven wheels. If you ask for full torque (floor it), the battery and engine+generator are both sending current to the drive motor, giving you more power. In this state, it would make sense for the engine to be generating max power.

Gotta love Mazda’s resilience with keeping the rotary alive.

I had an 87 rx-7 and it's the least surprising thing in the world to read that a lot of the fuel went out the exhaust. You could stand behind it and see/smell it happening. It was my favorite car ever.

You've mastered the art of explaining complicated technical subjects in a way anyone can understand. I love every minute of your videos.

Funny story: Many years ago I worked with a large team of engineers who were submitting analysis of car motors for the EPA. We wrote the study you mentioned 😁. Also your white board is concise and easier to read compared to the 10 or 12 we had in our office. Also, our paper found according to the current rotary engine schematics that Mazda provided at that time, we found so many issues with operation and inconsistencies with their EPA readings. I hope Mazda has found a better way this time. I'll remain skeptical for now

I appreciate how engineers can complicate simplicity

Fascinating how using the rotary as a hybrid actually improves the efficiency of the engine itself rather than just the efficiency of the overall system. Very cool indeed.

I have to say, this is EXACTLY what I've been saying the Wankel engine should be used for. A single-rotor range extender that can run at a more-or-less constant RPM takes the best advantage of all that the Wankel has to offer. Granted, I also believe Mazda should seriously consider throwing on a big-ass turbocharger because turbo lag doesn't matter on a range extender, but maybe in the future. Of course, I would love to see non-hybrid rotary car at some point, too, but I'll take my wins when I can. A range-extender is a great way to keep this fascinating technology alive, and I support Mazda 100%.

I love how when you really break down the complexities of a system like this, even if the device is boring or lame, once you understand the system, it suddenly becomes fascinating. That being said, I can't wait to see what Rob Dahm does with these rotors and housings haha

I love knowing that Mazda has not given up on the rotary. Mazda is a very special company, if you look at their history, people and passion in that company - they are so impressive. That being said; this is definitely not the rotary 99% of us wanted. 🙃

Will it last over 100k miles before needing rebuild?

This is the second of your videos i've watched, and I'm absolutely blown away!! Subscribed, think i'm going to enjoy binge watching your previous videos! Thanks for the clear and concise way you explain very complicated subjects!

Absolutely love Mazda's dedication to keeping the rotary alive and even improving it out in these times. I can't help but feel another rotary beast is on the cards, but we can only be hopeful

Honestly, I really love this idea, I drive a Chevy volt, so I’m obviously biased, but most trips are short electric trips. And so it works perfectly fine. You can make 4 plug-in hybrids with the same amount of batteries as 1 full EV with decent range. And the overall salts in more electrical miles driven.. 1 ev and 3 ice versus 4 plugins results in total in 25 and 75% of miles driven electrically for same battery capacity: 1+3/4 =25% vs 0.75*4/4 = 75% The one issue with plug-in hybrids is that you’re still lugging around an engine and this is where a Wankel makes a ton of sense. It’s light and it’s simple, and it does still save you from lugging around the giant battery so in the end you’re winning out. I honestly think for as long as we are battery constrained this is a fantastic option.

What an awesome video. I posted a comment concerning the added vibration of this (angular deceleration must be transferred into some (small) linear acceleration) but then I un-paused and you answered my question. I love how you anticipate what your viewers are thinking so well.

I been wondering for years, close to decades now, why rotarys aren't used in hybrids. Seems like a great pairing to me.

Very clever, I use a single rotor 13B in my aircraft, the 13B is well suited to aircraft as we don't have anywhere near the RPM variations that automobiles have. We are able to tune the intake runner to give us maximum volumetric efficiency at our desired RPM. In general we only have power variations on take off to cruise and then to landing, there are other times we might want to reduce or increase power but way less than an automobile.

I love your enthusiasm, makes me feel comfortable in how much excitement I find myself enjoying when I quest down these rabbit holes.

I love your videos. You do the best job at breaking things down, so even guys like myself that aren't as familiar with rotary engines, can easily follow along and get a better grasp at what is going on. Who would think that a white board and colored dry erase markers could do such an excellent job as a teaching aid? Lol!

The amount of joy I got from this video is substantial. I can't wait to see what Japan really brings to the EV market.