Featured Rotary returns as range extender

Sounds like a bevx, where you don't care about fuel economy or power but cost. Economy doesn't matter because it has to go as far on batteries as gas. A compliance concept.

Mazda EV with rotary range extender seems confirmed - Autoblog

Looks like its likely a compliance type phev with around a non-turbo 0.33L single rotor wankel engine as they used in their concept car. In order to get around the pollution and efficiency problems inherent in the rotary design probably will spin in a very small rpm range using the battery. The last wankel mazda made had 2 times the displacement/rotor and 2 rotors and weighed 248 lbs. This probably is in the range of 100 lbs before fluids, but emissions controls and the fluids won't make it much lighter or smaller than say a 1.2L 3 cylinder skyactiv that would be more efficient. The goals seem to be marketing of the wankel and better nvh than a 3 banger (or indeed the 2 cylinder in the i3).

Next-Gen Mazda2 To Get Rotary Range Extender?

In the demo 4 years ago the engine made 26 hp. I assume the weight includes a generator and fluids, since the prius engine without fluids only weighs 220 lbs.

 

i hope it's not another failed attempt at making the wankel something it isn't.

 

that will be great if it doesn't pollute more.

 

I will have to say one thing, when the Wankel is right, it's a raped ape. Back in the 80's a couple of guys on the midget circuit ran Wankel power plants when 4 cylinders were the engines of rule. The VW pancake was the typical hot number due to the low center of gravity, but the Wankel led the pack when they got it tuned right.

Here's a video of a Wankel car. It's the No. 76.

 

All I remember of the Wankle was losing some money on ToyoKogo (= Mazda) stock, the stories about seals and its demise when MPG became important. I wanted it to succeed but ...

Just maybe 25 years worth of research and improved materials and manufacturing techniques have made it possible.

 

My 4 passenger 1970 Subaru 360 cc two cycle made 25hp with a 66mpg 52mph rating.

It also came in a HO 35 HP version

Using modern controls, direct injection, and high compression I have no doubt a simple 2 cycle could beat 4 cycle efficiency, meet modern emissions, (they do in Japan) likely be more durable and reliable than a wankle and likely output more HP.

Ah well too bad Chrysler’s 50mpg 2cycle Neon project never left design phase.

 

Wow! I had one of those Subaru 7 seat microbus once on Cyprus...
.. like a shrunken VW Combi, but I thought it was great with its small 2x cylinder 4 stroke air-cooled engine. Heater would work going up Mt Olympus, but you'd freeze when the engine ran cold on the way down again. Think it was called a Sambar.

 

Interesting!

Typed by Mr88cet’s dancing thumbs

 

saw a few of those as mico-pickups when i was a kid. Man ... even getting hit by something as light as a Corvair, they have to scrape the subaru off the asphalt w/ a spatula.

.

 

As a bigger car, and most likely lower price, it should, but we really know very little about this Mazda.

The BEVx is a CARB construct. Since this news is coming from Europe, this Mazda shouldn't have those CARB constraints as designed.

While a rotary has its disadvantages, its advantages over a piston engine make it a better fit as a range extender. Smaller size means more space of batteries, or less loss of passenger and cargo space. For those looking to buy a BEV w/ range extender, the better NVH will be important.

The Mazda2 concept had a 20kWh pack. I expect this production car will have a 100 or more miles of EV range. As the utilization rate of EV miles increases, the point efficiency of the range extender becomes less important. Amount of ICE fuel used per week, month, or year become a more relevant measurement for individuals than MPG. Emissions could remain a concern with the rotary, but without hobbling by CARB, the driver can limit ICE use to outside residential areas to help mitigate those.

Audi had a fleet of a dozen or so A1 E-tron PHEVs using a 255cc rotary in series as a range extender. This was back when the Volt first came on sale, so the specs aren't as impressive today, but it is smaller than a Mazda2. 30 miles of EV from a 12kWh pack with another 125 from the 3 gallon gas tank. Compared to the ICE model, this PHEV lost no interior space to the battery. The the genset actually was mounted between the rear wheels.
Audi A1 E-Tron Concept – Review – Car and Driver
Audi Posts Results From A1 e-tron, A3 e-tron Real-World Trials

 

Have you seen how small the 3 cylinder engines are now? Nissan, Ford, BMW and Mercedes through smart have really tamed the 3 cylinder.

Rotaries besides low compression are designed to burn oil and need to be fully warmed up. IIRC mazda is using oil injection to control this amount. This oil use is probably OK is the engine is only used in a small percentage of trips.

Mazda is leaking that it will be horizontally oriented, which is not a good configuration for a inline 3. This may give the same packaging advantage as flat 4 cylinder engine. I'll give you NVH, but if maintenance and fuel consumption are higher will that sell cars? I'll wait and see, but it seems like a poor engineering choice to me. Perhaps it is a low volume compliance car, and it gives those mazda engineers that want the rotary to remain a little nastalgic pride.

Well I agree here.

Well sure, but mazda during that time period couldn't get there rotary to pass US emissions without adding some expensive equipment. Audi's test showed them that the rotary wasn't a good fit for their phev.

Let's look at some numbers. Mazda's 0.33 L rotary looks from pictures to have a bigger footprint than the nissan 400 hp, 88 lb 1.5 l 3 cylinder, but it is shorter. Shrink the cylinders down to the 0.3 L that mercedes uses on the smart car, and use a cast iron block like ford uses to reduce size and reduce warm up time, and costs for that 3 banger shrink, but weight probably rises to 100 lbs. Use it in an atkinson cycle (perhaps 14:1 expantion, 9:1 compression like the prius) and there does not need to be much oil or coolant especially if the engine is kept between say 1800-4000 rpm where nvh is actually quite good.

My guess is mazda will make a prototype and perhaps a low volume car, but kill it before any real volume is made.

 

My understanding was that the higher ups would rather use some off the shelf piston engine to cut costs than whether the rotary worked for the PHEV or not. The the recession happened, and the project got axed.

Does Mazda have such an engine in their portfolio? Can they downsize a current engine model if not? Space considerations will mean any SkyActiv one will lose the benefit of the 4-2-1 exhaust manifold.

Mazda's rotary experience means they have a better shot of getting this to market than Audi. In the US, it may just be a compliance car, but because of CARB's required hobbling of such a vehicle types for ZEV credits. Though I guess Mazda could just launch BEV for that needs.

 

BMW uses a motor cycle engine manufacturer to contract their engine in the i3. Mazda is partnering with toyota on phevs, and Toyota would be the obvious source which has ... a 1L 3 cylinder port injected atkinson engine that has a thermal efficiency of 37%. It should be less expensive to make than any of the skyativ designs and is quite small.

Mazda does have older designs that would work, but contracting to anouther manufacturer would probably cut costs most. If size is the biggest problem, and they build it in a north american plant, they could probably contract to ford, which they often shared designs in the past. The 1L block is probably great, but mazda would likely redesign the aluminum head and piston for non-turbo application. There is no need for a fancy manifold if this is a low rpm atkinson design, high expansion not compression is called for.

audi has much deeper pockets than mazda, but sure. I just don't think that it will be very interesting if they bring it.

 

Mazda was forced to share with Ford because Ford held majority stake in them. They were quite happy when Ford sold off most of that stake. They'd much rather work with Toyota, and they already are for their Japanese hybrid offering. If they wanted to outsource the engine.

BMW makes motorcycles, so they know motorcycle engines. Mazda knows rotary engines, and it appears they have been working on SkyActiv rotaries for other possible cars.

It is going to be an optional range extender to a BEV. For a series hybrid, most people probably couldn't tell what type of ICE is being used while driving it. But a rotary just have a publicity advantage for Mazda.

 

I'm not so sure about that narrative, but the first engine I picked was the toyota/Daihatsu 37% efficient 1L. Not because its the best, but because its cheap, there is a relationship, and it will do the job. Daihatsu (wholly owned by Toyota) even modified the engine for Perodua for the Malaysian market. I believe Perodua is partially owned by Daihatsu.

Well sure, but that bmw designed motorcycle engine wasn't the best fit for the i3, its that they hadn't gotten around to building and testing their 3 cylinder car engines. It is contract manufactured by Kymco, taiwan. The rex is underpowered, which made it louder than it should have been. They increased sound insulation in 2017.

Mazda has a good thing going with skyactiv-x and skyactiv-3. I'm sure there are fan-boyz that will like the idea of a rotary, but if it doesn't perform as well as a 1-1.2L 3 banger (e-power) or 1.5L 4 cylinder (volt, clarity, prime) and has to go to a low power mode like first gen i3 and rotary a1 I think it hurts mazda. Its a relatively small company. Its fine for the lab or a compliace trial, but I doubt this will make a real production car. It will be interesting to see what happens. BMW has sold over 100K i3s. Its an interesting experiment, but it came out awhile ago. I don't expect another 2 cylinder phev unless its chinese or indian. One of my dad's friends had an rx-7. It was a cool car, but inline and v engines have come a long way with better valving, direct injection, etc.

 

The whole range extender market will be interesting to follow. I can't help but think that the rotary concept would be very efficient with some design focus.

I like the concept below with two exceptions: the unit should be light enough to "plug into" a receiver (like a hitch) to eliminate the friction from the tires. I would also like to see a self-adjusting aero package on the unit that would sense the atmospheric drag and find the sweet spot for the vehicle it is on and the conditions. I am sure that engineers could get fairly creative. If wheels are required, the extender might include a "pusher" option to limp a car to a safe spot or a charging station.

 

The problem was created by CARB's hobbling. Drivers of the i3 REx know when they are going to be exceeding the EV range. In Europe, they can turn on the ICE once they've used up a little of the battery charge. In the US, they have to wait until the battery is nearly depleted before they can use the ICE.

Considering who is talking in Mazda about this, it may not even come to the US. I think EREVs like the i3 REx are a great solution to concerns about charging infrastructure. Get to 100 to 125 mile EV range, and most of the miles driven will be on the grid. A low power ICE for a range extender saves cost, weight and space. It won't provide full power to the car on its own, but it shouldn't have too when its main job is for cruising on the highway between gas stations and chargers. CARB screwed us over with their hobbling.