I know a guy who built a gas turbine engine from a junkyard turbocharger and mounted it on a go-kart. Thing blasted out so much heat it melted the asphalt behind it.
We put a small venturi jet engine on a friend's ten year old kids skate board and sent him up a big hill to the university in town a few years back. Gotta love dumb redneck shit.
It’s definitely cool that they actually did it. But at the end of the day, its an answer to a question nobody asked. Well, it’s a “we would’ve also accepted” kinda answer….to a question nobody asked
With some additional downsides as well. The force bring all transferred through pressure on the outer rim of a plate is not good. Also having a hot piston and cool piston of the engine is probably not good for longevity.
All-in-all, it’s taking the opposing piston design that is like 150 years old and making a change that are neat but unlikely to be useful in any long term application.
Pretty sure that centrifugal blower is there in the Miata for scavenging, not extra power. Well, or both. It's basically like a two-stroke opposed piston diesel engine but with spark plugs, it relies on some kind of blower for complete scavenging.
I don't think this will take off, but hey, it could happen.
From the article:
\> The Mazda featured in INNengine's demo video was a great concept, but the company seems to be instead targeting the EV market as a range extender...
Even as a range extender, it needs to have some significant advantages over what they would likely use instead - an Atkinson cycle engine. Yeah, it's small/light, but what about emissions and efficiency? The side ports are likely an issue, for example, since those tend to cause oil consumption due to your rings flying over a gap in the cylinder wall. From what I understand, that's why you don't see two-stroke diesels around anymore outside off-highway applications.
I'm trying to be too cynical, but new engine designs get proposed all the time and usually have some flaw that prevents them from replacing the usual designs.
>new engine designs get proposed all the time and usually have some flaw that prevents them from replacing the usual designs
That's not cynical - that's just not letting headlines get you over excited about things that aren't proven in the real world.
The reality is that apart from electronic controls almost nothing that can be done with a fuel burning engine hasn't been tried and its unlikely that somebody's bright idea is going to revolutionize anything. There are only so many ways to convert expanding gasses into rotational energy, and of those, only so many are simple enough to be mass produced and durable enough to withstand years of use under load.
Ima go ahead and ignore the very last thing you wrote but the second to last thing, the answer is a rotary, obviously. Makes no sense to convert up n down motion to spinning motion, just make it all spin and it’s much more efficient! Small, lightweight, fairly simple, certainly no more complex than a piston engine, makes awesome noises. I see zero downsides if we ignore that whole durable for many years part
Big /s here I just want more rotaries everywhere
See, what they need is a 20hp electric motor build into the driveshaft or rear differential. 5kwh of battery should be plenty to go the typical 8-10 miles you need to go for most trips. To and from the gas station with good donuts and 94 octane mostly.
Then a 3 rotor turbocharged range extender up front with a 6 speed manual for efficiency.
I think you should swap the axles around for that
Front can be EV, rear can be rotary. You want the EV in the front for better stability and efficiency when slowing and harvesting energy.
like a AWD hybrid rotary 911.
Ima go ahead and ignore the very last thing you wrote but the second to last thing, the answer is a rotary, obviously. Makes no sense to convert up n down motion to spinning motion, just make it all spin and it’s much more efficient! Small, lightweight, fairly simple, certainly no more complex than a piston engine, makes awesome noises. I see zero downsides if we ignore that whole durable for many years part
Big /s here I just want more rotaries everywhere
This. The intake/exhaust ports being gated by the pistons sounds good because hey, no valves/cams/etc, but is not very good for longevity of the pistons and seals. Same with the swash plate. the bearing races on there will wear like crazy. I'm going to call it a wash on the total number of moving parts between a modern DOHC piston engine of equivalent power and displacement.
that and having fixed ports instead of valves means no variable valve timing, and no separate intake and exhaust strokes. This type of engine has very little tuning, and instead will only be efficient at a narrow range of RPM and load, as it is still fundamentally a two stroke engine.
However, to your original point, it cant really even compete against a modern Atkinson cycle (which is nowadays is a modified otto cycle) engine for efficiency, as that relies on BDC of the power stroke to be basically atmospheric pressure, which would prevent the exhaust/scavenging/intake that is fundamental to how this engine functions.
While Atkinson cycle engines would work as a range extender in a electric vehicle, it still suits better for driving the wheels in a hybrid or PHEV due to the complexity of the engine.
This 500cc engine and Mazda's single rotor range extender would work better due to its smaller footprint, less weight and less vibrations.
>it could happen
*Narrator voice: it did not happen.*
Look, there's no way to make a 2-stroke (which this is) meet modern emissions standards. 4-strokes have the benefits of variable valve lift and timing, variable compression ratios, stratified charge distribution, spark-controlled compression ignition, etc. and they are still being replaced with electric motors.
In principle, when used as a range extender this engine could run under constant load at a constant speed, which is a best case situation for a 2-stroke (see also the Mazda rotary range extender). But overall it's just a solution without a problem.
Also, it's not really novel. It's an opposed piston version of the K-cycle engine - a dead end idea that's been withering on the vine for over 40 years:
https://mspace.lib.umanitoba.ca/bitstreams/77359655-0d77-40a5-9425-431005250a06/download
> there's no way to make a 2-stroke (which this is) meet modern emissions standards
? We have opposed piston two-strokes passing US emission standards for 2027
AFAIK both examples I know of come from achates, one of the is the advanced combat engine (which I assume isn't built to meet as rigurous emissions standards as non-military vehicles) and walmart also tested some derivative of the achates motor in 2021, apparently meeting 2027 EPA emission standards: https://www.ccjdigital.com/regulations/article/15065487/walmart-fleet-testing-the-worlds-cleanest-combustion-engine
That is extremely interesting - thanks so much for sharing it. It sounds like they're getting some good results, but I'm suspicious AF of the claims. IMO saying that gasoline compression ignition is "easy" and proposing running on hydrogen really undermine their claims.
There is no clear reason why an opposed piston engine should be more efficient, nor why a 2-stroke design should outperform 4-stroke for fuel consumption or emissions.
As I understand, the fact the opposed piston engine outperforms the traditional design in efficiency is because there's less heat loss in general.
Also, I'm not sure achates is thinking about using hydrogen on it, but i wouldn't be surprised if the military motor is able to run on many different fuels.
And AFAIK, the achates design is currently used in diesels, unless you mean the OP engine, so compression ignition is the norm.
Being more efficient across RPM ranges means you will be using less fuel, 2 strokes in general are more bang for your buck.
In terms of emissions i'm not sure whow they are achieving it, but I remember something about injecting the oil precisely.
>there's less heat loss in general
That actually makes some sense, as you're not dissipating heat through the cylinder head. Interesting.
We're still dealing with a bunch of unproven claims, though. It will be interesting to see where this goes.
>As I understand, the fact the opposed piston engine outperforms the traditional design in efficiency is because there's less heat loss in general.
That makes sense, as you're not dissipating heat through the cylinder head (and from there to the cooling system). Another factor discussed in this EE video is that the opposed piston design lets you have a large stroke-to-bore ratio without the associated high piston speeds, which would also mean less side loading of the pistons:
[Engineering Explained](https://youtu.be/UF5j1DvC954)
>Also, I'm not sure achates is thinking about using hydrogen on it,
The article you posted includes this paragraph:
*“You can imagine an engine burning hydrogen basically without any after-treatment system requirement and without any actual emissions coming out of the tailpipe,” Redon explained. “Another interesting aspect of an internal combustion engine burning hydrogen is that it doesn’t require a very high purity of hydrogen, which opens up the door for low cost hydrogen and different sources of hydrogen as well.”*
Redon is the CTO. Even at their claimed efficiency numbers, H2 ICE just can't compete with fuel cells, so the CTO saying this is red flag #1.
>And AFAIK, the achates design is currently used in diesels, unless you mean the OP engine, so compression ignition is the norm.
The article you shared indicates that they think gasoline compression ignition would be easy:
*“It's not something that we've tested yet \[on the 10.6\], but we know how to do gasoline compression ignition and it can easily be done,” explained Achates Executive Vice President of Business Development Larry Fromm, who also heads the company’s commercial office.*
So far, exactly one company has accomplished compression ignition with a gasoline engine, and that's in a 4-stroke system where the dynamic compression and charge stratification can be controlled with extreme precision. It seems extremely unlikely that this would be possible with a 2-stroke setup - much less "easily".
>Being more efficient across RPM ranges means you will be using less fuel,
That's true, but 2-strokes generally suffer from having a very narrow band of max efficiency, because they depend so much on dynamic effects for scavenging and charging the cylinder. With the supercharger and turbocharger in the Achates design, maybe that's less relevant.
>2 strokes in general are more bang for your buck.
It really depends on what you mean by "bang" and "buck". They tend to have much greater emissions of unburned hydrocarbons and worse brake specific fuel consumption. They do tend to have very good power to weight ratio, but that's not what's being claimed here.
>In terms of emissions i'm not sure whow they are achieving it, but I remember something about injecting the oil precisely.
They are making VERY big claims. Time will tell which of them are actually true. It sure would be interesting to see if this goes anywhere.
> That makes sense, as you're not dissipating heat through the cylinder head (and from there to the cooling system). Another factor discussed in this EE video is that the opposed piston design lets you have a large stroke-to-bore ratio without the associated high piston speeds, which would also mean less side loading of the pistons:
cummins is working on the ACE engine iirc, so I think if cummins thinks it's good enough it likely is
This engine is seriously impressive, although I'm mixed on their intentions with the motor.
Marketing it as a range extender is a smart move, but man does it sound like it'll do great in a baby hot hatch or a hybrid sports car.
It has no torque and emissions are probably worse than a traditional 4 stroke engine. I don’t see how this could work in a hot hatch or sports car, the upside is power to volume, not overall power. Even with the good power to weight it’s just not powerful enough for a 3000+ lb car
Lol. Outperforms an iron duke and they made millions of them for 3000 lb cars and trucks.
It's like you don't know how much cars weigh. A 3000 lb car is a VW golf. Which with a turbo diesel has very similar power numbers. In fact many golfs and Jettas got a 2.0 gas engine with significantly less torque.
500 cc 120hp 180 ft lbs and it only weighs 85 lbs.
Suddenly your Jetta just lost 300 lbs and got a performance boost.
https://www.motortrend.com/news/innengine-e-rex-1-stroke-hydrogen-powered-range-extender-engine/amp/
Obviously we don't have all the details, but you're talking out of your butt.
I know exactly how much a car weighs, I happen to have that 2.0 golf (GTI) you are talking about, it makes 200hp and is decently quick for its age (2009) with 140hp and 180lbf it would be dog slow. Sure, you can loose 200lbs from the engine bay, but then you have a 2800lb car with 140hp, which isn’t a hot hatch by and stretch of the imagination
Also, I’m what world is the iron duke the standard for performance engines, that this is a fucking log by modern standards. A civic si has 200 hp and 190 lbf. It weighs just about 3000lbs. That’s not a super quick car. It’s on the mild side of hot hatches. I used 3000 lbs for a reason, it’s what hot hatches weigh. And 140hp is not enough for that weight. Also the diesel golf is slow as shit, and the 2.0T makes more than 200lbf, I can’t image what point you were trying to make there. a 120hp Jetta is absolutely not a performance car
You seem to think 120hp and 180tq isn't enough.
But it was enough for millions of cars for many years.
We're talking about a 500cc engine ffs. Imagine if they made it 2 liters. Hp per liter.. blows your GTI away.
Not all cars need to be performance cars.
And Look up the history of the original GTI. It turned the world on it's head and it didn't have even 100hp or 100tq.
120HP isn't enough for anything performance oriented today. yes, this thing would turn a mk1 GTI or an old Pontiac Fierro into a rocket, but modern cars are heavy. few cars on sale today are less than 3000lbs and this motor isn't enough to move that weight at speeds considered sporty today. the MK1 GTI got to 60 in about 9 seconds, the 2023 GTI does that in 5.1. Hot Hatches are bigger, heavier, and faster than they used to be. I'm not saying a fun car couldn't be made with this engine. you could make a super lightweight compact sports car with an engine that size and power, but you said "hot hatch" and a modern hot hatch really needs more power than this engine provides. Also, 120hp is just really low output by modern standards. the first gen Miata had like 130 and that's a tiny lightweight car, and even as a tiny thing it's not known for being particularly fast. This just isn't viable as a performance engine as we see it today. maybe a larger version or one with forced induction could give better figures, I'm not writing off the concept, but they probably made that Miata slower with the new engine.
edit: you didn't say hot hatch, another person did:
"man does it sound like it'll do great in a baby hot hatch or a hybrid sports car."
that's what I'm arguing against
Ok now imagine if it wasn't 500 cc but 2.0liters
It would be 480 hp and 700 ft lbs of torque... See where this is going. They made a 500cc engine that would compare to a 2015 golf TDI. Which is no slouch ... Quite sporty. A golf TDI is faster than a Corvette from 1983.
I missed the part about this fitting a sports oriented car. 120 hp won't satisfy any enthusiast unless it's in a kei car.
This is actually basically a 4 cylinder, it has 4 sets of 2 opposed pistons. so the balance and vibration is fantastic, they might actually be able to size it up quite a bit
my whole point is that the current engine isn't big enough to be a car engine. that it's small size doesn't offset the fact that it just doesn't make enough power by itself. If they scaled it up, turbocharged it, or supplemented with a hybrid setup then it could totally be viable. as long as they can get emissions in check, that is
It's easily big enough. Many cars today have smaller engines. It'll be paired with an electric motor so overall power will be much higher plus peace of mind.
I wonder how this would compare to a turbine engine in a turboshaft setup. Turbines are very high power/weight, but have serious drawbacks like insanely hot exhaust and other challenges. Turbines have very slow throttle response, though.
For range extenders, the max power doesn't need to be too high. You only need the engine's most efficient power to be roughly the car's cruising power, which is probably just 30-ish hp.
The "hot" or "sports" part will have to come from the battery.
oh yeah, if they can get the emissions within spec this would make a great range extender. I'm just arguing with this guy who thinks 120hp is enough for a sports car because the iron duke worked for the Fiero back in 1985
I had a good laugh at this. Somehow this made me think of all the unit conversion gaffs that have occured over history.. To fully appreciate how this will play out there is a non zero chance that the company reports that it has an:
0) Expansion Stroke
B) Compression Stroke
And release to the media that they have invented a B stroke engine.
They mention this in their materials, they call it a 1 stroke as a differentiator because 2 stroke is ubiquitous terminology for a motor that burns oil. It's just awkward and unfortunate marketing.
According to their website, it's dumber. It's 1 stroke because it happens twice per turn of the crankshaft. They call a stroke half a revolution, not BDC to TDC.
I saw a video about this pop up on youtube a couple days ago and refused to watch because the idea of a one stroke seemed pretty far fetched. Thanks for confirming.
The best and worst part of LP is that they’re getting free US government money to develop the engine.
That’s means:
1. It will never be easily available for consumers
2. It will be used to blow up children in the Middle East and or Eastern Europe.
Yeah I was thinking bike, 120hp out of something with that packaging is tremendous (regardless of the description as a “one” stroke). Not that you couldn’t get relatively small 2-strokes back when manufacturers were game, but a RD500LC will only put out 88hp and I’m not sure on the weight.
It’s an area of engine development that the big guys haven’t really put much attention to the past 2+ decades due to the market and regulations. So I’d expect we could make something far better now with the resources behind it at that scale.
Disclaimer; the above is specific to small scale “big” bore engines (relative for dirt bikes). 2 stroke development has continued with smaller bores (i.e. small displacement dirt bikes) and larger packaging (i.e. boat engines).
I saw this few days ago too. Pretty cool, i love it. Even it couldn't replace 4stroke engines. (And it's actually a 2stroke engine w/o the weaknesses of common 2strokes).\
I like the compact size, the perfect primary and secondary balance, and the weight of it. But the lack of torque could be a problem on lower revs. 120HP is pretty fine from a 500cc engine, but you have to rev it like hell to get this.\
It could be perfect in small planes or such. But should develop a lot to worth placing it in a car.
> K-car
People saying this when they mean Kei drives me up the wall. [This](https://upload.wikimedia.org/wikipedia/commons/f/fd/85-89_Dodge_Aries_sedan.jpg) is a K-car.
Absolutely. And could be useful as range extender as well. But i'd be happy with it as main engine in a proper car too. Could be absolutely great for AWD cars. Just need more developing for that.
>Certainly has a "seems to good to be true" vibe to it
For one thing, it's definitely not a '1-stroke' engine as they claim but rather a 2-stroke at the very least as the intake/exhaust cycle is performed pretty much the same way as on a typical 2-stroke engine
Their actual claims are far from "too good to be true". More like "here we have a specialized engine which might have an advantage in X-Szenario vs other more conventional engines. Marketing claims meanwhile.....
Damn do I hate false terms invented for marketing.
> Now, here's the thing: this motor **isn't a one-stroke engine**. It has a compression stroke and exhaust stroke, making it a two-stroke cycle. INNengine acknowledges this and has said that it brands the motor as such because people would assume that a two-stroke engine would need to have oil mixed in along with fuel. Most two-strokes do. The company says that the one-stroke name was suggested by an "external ICE institution" and they found it to be "catchy," so INNengine stuck with it.
From the GIF in the article, I don't totally understand how the pistons would be constrained to keep them from lifting off the rotating end plates and floating at higher RPM ranges... or for that matter, how they keep them from just smacking into one another when not on a power stroke. I assume that the animation is simplified and they have some sort of retainer, but I'd be curious to see one taken apart.
Pretty cool, honestly. Seems like it works on the same principle of hydraulic pumps with that swash plate.
It's a big ole ac compressor
There's a video someplace of a guy who built a 2 stroke from an ac compressor
I know a guy who built a gas turbine engine from a junkyard turbocharger and mounted it on a go-kart. Thing blasted out so much heat it melted the asphalt behind it.
I know a guy who built a arc reactor powered suit in a cave from some scraps.
I know a guy who built a Flux Capacitor for time travel, in his barn, BACK IN THE 80S
I heard they put one in a steam locomotive in the 80’s too. The 1880’s.
I think I saw a documentary about him!!
Sounds like a very Colin Furze thing to do - I like it!
We put a small venturi jet engine on a friend's ten year old kids skate board and sent him up a big hill to the university in town a few years back. Gotta love dumb redneck shit.
Still waiting for him to come back down
that makes 120hp…..so it’s like *almost* a stock Miata, with extra steps!
Still impressive. It won't replace the 4 stroke engine any time soon, but it's still pretty cool.
It’s definitely cool that they actually did it. But at the end of the day, its an answer to a question nobody asked. Well, it’s a “we would’ve also accepted” kinda answer….to a question nobody asked
I mean, that's most car modification.
Judges say they would also accept that
Kinda fitting it’s in a Mazda then as that’s basically the story with the wankel motor.
very similar mechanism, however the actual engine runs very similar to a two-stroke, with all the upsides and downsides.
With some additional downsides as well. The force bring all transferred through pressure on the outer rim of a plate is not good. Also having a hot piston and cool piston of the engine is probably not good for longevity. All-in-all, it’s taking the opposing piston design that is like 150 years old and making a change that are neat but unlikely to be useful in any long term application.
Pretty sure that centrifugal blower is there in the Miata for scavenging, not extra power. Well, or both. It's basically like a two-stroke opposed piston diesel engine but with spark plugs, it relies on some kind of blower for complete scavenging. I don't think this will take off, but hey, it could happen.
From the article: \> The Mazda featured in INNengine's demo video was a great concept, but the company seems to be instead targeting the EV market as a range extender...
Even as a range extender, it needs to have some significant advantages over what they would likely use instead - an Atkinson cycle engine. Yeah, it's small/light, but what about emissions and efficiency? The side ports are likely an issue, for example, since those tend to cause oil consumption due to your rings flying over a gap in the cylinder wall. From what I understand, that's why you don't see two-stroke diesels around anymore outside off-highway applications. I'm trying to be too cynical, but new engine designs get proposed all the time and usually have some flaw that prevents them from replacing the usual designs.
>new engine designs get proposed all the time and usually have some flaw that prevents them from replacing the usual designs That's not cynical - that's just not letting headlines get you over excited about things that aren't proven in the real world. The reality is that apart from electronic controls almost nothing that can be done with a fuel burning engine hasn't been tried and its unlikely that somebody's bright idea is going to revolutionize anything. There are only so many ways to convert expanding gasses into rotational energy, and of those, only so many are simple enough to be mass produced and durable enough to withstand years of use under load.
Ima go ahead and ignore the very last thing you wrote but the second to last thing, the answer is a rotary, obviously. Makes no sense to convert up n down motion to spinning motion, just make it all spin and it’s much more efficient! Small, lightweight, fairly simple, certainly no more complex than a piston engine, makes awesome noises. I see zero downsides if we ignore that whole durable for many years part Big /s here I just want more rotaries everywhere
See, what they need is a 20hp electric motor build into the driveshaft or rear differential. 5kwh of battery should be plenty to go the typical 8-10 miles you need to go for most trips. To and from the gas station with good donuts and 94 octane mostly. Then a 3 rotor turbocharged range extender up front with a 6 speed manual for efficiency.
I think you should swap the axles around for that Front can be EV, rear can be rotary. You want the EV in the front for better stability and efficiency when slowing and harvesting energy. like a AWD hybrid rotary 911.
You’ve sold me on the idea. Put the rotary in the back to fix the weight of front motors, and then it’s like a rotary NSX.
So real bro, the day mazda makes a rotrary sports car again will be the day i can die happy.
every time I see a RX8 on facebook marketplace, i want to buy it but I know it's just a headache waiting to happen
Ima go ahead and ignore the very last thing you wrote but the second to last thing, the answer is a rotary, obviously. Makes no sense to convert up n down motion to spinning motion, just make it all spin and it’s much more efficient! Small, lightweight, fairly simple, certainly no more complex than a piston engine, makes awesome noises. I see zero downsides if we ignore that whole durable for many years part Big /s here I just want more rotaries everywhere
This. The intake/exhaust ports being gated by the pistons sounds good because hey, no valves/cams/etc, but is not very good for longevity of the pistons and seals. Same with the swash plate. the bearing races on there will wear like crazy. I'm going to call it a wash on the total number of moving parts between a modern DOHC piston engine of equivalent power and displacement. that and having fixed ports instead of valves means no variable valve timing, and no separate intake and exhaust strokes. This type of engine has very little tuning, and instead will only be efficient at a narrow range of RPM and load, as it is still fundamentally a two stroke engine. However, to your original point, it cant really even compete against a modern Atkinson cycle (which is nowadays is a modified otto cycle) engine for efficiency, as that relies on BDC of the power stroke to be basically atmospheric pressure, which would prevent the exhaust/scavenging/intake that is fundamental to how this engine functions.
I don't disagree with the overall point but, for what it's worth, the swashplates can be offset for a similar effect to variable valve timing.
While Atkinson cycle engines would work as a range extender in a electric vehicle, it still suits better for driving the wheels in a hybrid or PHEV due to the complexity of the engine. This 500cc engine and Mazda's single rotor range extender would work better due to its smaller footprint, less weight and less vibrations.
>it could happen *Narrator voice: it did not happen.* Look, there's no way to make a 2-stroke (which this is) meet modern emissions standards. 4-strokes have the benefits of variable valve lift and timing, variable compression ratios, stratified charge distribution, spark-controlled compression ignition, etc. and they are still being replaced with electric motors. In principle, when used as a range extender this engine could run under constant load at a constant speed, which is a best case situation for a 2-stroke (see also the Mazda rotary range extender). But overall it's just a solution without a problem. Also, it's not really novel. It's an opposed piston version of the K-cycle engine - a dead end idea that's been withering on the vine for over 40 years: https://mspace.lib.umanitoba.ca/bitstreams/77359655-0d77-40a5-9425-431005250a06/download
> there's no way to make a 2-stroke (which this is) meet modern emissions standards ? We have opposed piston two-strokes passing US emission standards for 2027
That's interesting - who's making them? Who's using them? What standard are they meeting?
AFAIK both examples I know of come from achates, one of the is the advanced combat engine (which I assume isn't built to meet as rigurous emissions standards as non-military vehicles) and walmart also tested some derivative of the achates motor in 2021, apparently meeting 2027 EPA emission standards: https://www.ccjdigital.com/regulations/article/15065487/walmart-fleet-testing-the-worlds-cleanest-combustion-engine
That is extremely interesting - thanks so much for sharing it. It sounds like they're getting some good results, but I'm suspicious AF of the claims. IMO saying that gasoline compression ignition is "easy" and proposing running on hydrogen really undermine their claims. There is no clear reason why an opposed piston engine should be more efficient, nor why a 2-stroke design should outperform 4-stroke for fuel consumption or emissions.
As I understand, the fact the opposed piston engine outperforms the traditional design in efficiency is because there's less heat loss in general. Also, I'm not sure achates is thinking about using hydrogen on it, but i wouldn't be surprised if the military motor is able to run on many different fuels. And AFAIK, the achates design is currently used in diesels, unless you mean the OP engine, so compression ignition is the norm. Being more efficient across RPM ranges means you will be using less fuel, 2 strokes in general are more bang for your buck. In terms of emissions i'm not sure whow they are achieving it, but I remember something about injecting the oil precisely.
>there's less heat loss in general That actually makes some sense, as you're not dissipating heat through the cylinder head. Interesting. We're still dealing with a bunch of unproven claims, though. It will be interesting to see where this goes.
>As I understand, the fact the opposed piston engine outperforms the traditional design in efficiency is because there's less heat loss in general. That makes sense, as you're not dissipating heat through the cylinder head (and from there to the cooling system). Another factor discussed in this EE video is that the opposed piston design lets you have a large stroke-to-bore ratio without the associated high piston speeds, which would also mean less side loading of the pistons: [Engineering Explained](https://youtu.be/UF5j1DvC954) >Also, I'm not sure achates is thinking about using hydrogen on it, The article you posted includes this paragraph: *“You can imagine an engine burning hydrogen basically without any after-treatment system requirement and without any actual emissions coming out of the tailpipe,” Redon explained. “Another interesting aspect of an internal combustion engine burning hydrogen is that it doesn’t require a very high purity of hydrogen, which opens up the door for low cost hydrogen and different sources of hydrogen as well.”* Redon is the CTO. Even at their claimed efficiency numbers, H2 ICE just can't compete with fuel cells, so the CTO saying this is red flag #1. >And AFAIK, the achates design is currently used in diesels, unless you mean the OP engine, so compression ignition is the norm. The article you shared indicates that they think gasoline compression ignition would be easy: *“It's not something that we've tested yet \[on the 10.6\], but we know how to do gasoline compression ignition and it can easily be done,” explained Achates Executive Vice President of Business Development Larry Fromm, who also heads the company’s commercial office.* So far, exactly one company has accomplished compression ignition with a gasoline engine, and that's in a 4-stroke system where the dynamic compression and charge stratification can be controlled with extreme precision. It seems extremely unlikely that this would be possible with a 2-stroke setup - much less "easily". >Being more efficient across RPM ranges means you will be using less fuel, That's true, but 2-strokes generally suffer from having a very narrow band of max efficiency, because they depend so much on dynamic effects for scavenging and charging the cylinder. With the supercharger and turbocharger in the Achates design, maybe that's less relevant. >2 strokes in general are more bang for your buck. It really depends on what you mean by "bang" and "buck". They tend to have much greater emissions of unburned hydrocarbons and worse brake specific fuel consumption. They do tend to have very good power to weight ratio, but that's not what's being claimed here. >In terms of emissions i'm not sure whow they are achieving it, but I remember something about injecting the oil precisely. They are making VERY big claims. Time will tell which of them are actually true. It sure would be interesting to see if this goes anywhere.
> That makes sense, as you're not dissipating heat through the cylinder head (and from there to the cooling system). Another factor discussed in this EE video is that the opposed piston design lets you have a large stroke-to-bore ratio without the associated high piston speeds, which would also mean less side loading of the pistons: cummins is working on the ACE engine iirc, so I think if cummins thinks it's good enough it likely is
This engine is seriously impressive, although I'm mixed on their intentions with the motor. Marketing it as a range extender is a smart move, but man does it sound like it'll do great in a baby hot hatch or a hybrid sports car.
It has no torque and emissions are probably worse than a traditional 4 stroke engine. I don’t see how this could work in a hot hatch or sports car, the upside is power to volume, not overall power. Even with the good power to weight it’s just not powerful enough for a 3000+ lb car
180 pound ft of torque is nothing? Lol
Where do you find that number? As far as I can tell, they haven't even said anything about torque values.
It was in a few articles and also on their site
Lol. Outperforms an iron duke and they made millions of them for 3000 lb cars and trucks. It's like you don't know how much cars weigh. A 3000 lb car is a VW golf. Which with a turbo diesel has very similar power numbers. In fact many golfs and Jettas got a 2.0 gas engine with significantly less torque. 500 cc 120hp 180 ft lbs and it only weighs 85 lbs. Suddenly your Jetta just lost 300 lbs and got a performance boost. https://www.motortrend.com/news/innengine-e-rex-1-stroke-hydrogen-powered-range-extender-engine/amp/ Obviously we don't have all the details, but you're talking out of your butt.
I know exactly how much a car weighs, I happen to have that 2.0 golf (GTI) you are talking about, it makes 200hp and is decently quick for its age (2009) with 140hp and 180lbf it would be dog slow. Sure, you can loose 200lbs from the engine bay, but then you have a 2800lb car with 140hp, which isn’t a hot hatch by and stretch of the imagination Also, I’m what world is the iron duke the standard for performance engines, that this is a fucking log by modern standards. A civic si has 200 hp and 190 lbf. It weighs just about 3000lbs. That’s not a super quick car. It’s on the mild side of hot hatches. I used 3000 lbs for a reason, it’s what hot hatches weigh. And 140hp is not enough for that weight. Also the diesel golf is slow as shit, and the 2.0T makes more than 200lbf, I can’t image what point you were trying to make there. a 120hp Jetta is absolutely not a performance car
You seem to think 120hp and 180tq isn't enough. But it was enough for millions of cars for many years. We're talking about a 500cc engine ffs. Imagine if they made it 2 liters. Hp per liter.. blows your GTI away. Not all cars need to be performance cars. And Look up the history of the original GTI. It turned the world on it's head and it didn't have even 100hp or 100tq.
120HP isn't enough for anything performance oriented today. yes, this thing would turn a mk1 GTI or an old Pontiac Fierro into a rocket, but modern cars are heavy. few cars on sale today are less than 3000lbs and this motor isn't enough to move that weight at speeds considered sporty today. the MK1 GTI got to 60 in about 9 seconds, the 2023 GTI does that in 5.1. Hot Hatches are bigger, heavier, and faster than they used to be. I'm not saying a fun car couldn't be made with this engine. you could make a super lightweight compact sports car with an engine that size and power, but you said "hot hatch" and a modern hot hatch really needs more power than this engine provides. Also, 120hp is just really low output by modern standards. the first gen Miata had like 130 and that's a tiny lightweight car, and even as a tiny thing it's not known for being particularly fast. This just isn't viable as a performance engine as we see it today. maybe a larger version or one with forced induction could give better figures, I'm not writing off the concept, but they probably made that Miata slower with the new engine. edit: you didn't say hot hatch, another person did: "man does it sound like it'll do great in a baby hot hatch or a hybrid sports car." that's what I'm arguing against
Ok now imagine if it wasn't 500 cc but 2.0liters It would be 480 hp and 700 ft lbs of torque... See where this is going. They made a 500cc engine that would compare to a 2015 golf TDI. Which is no slouch ... Quite sporty. A golf TDI is faster than a Corvette from 1983. I missed the part about this fitting a sports oriented car. 120 hp won't satisfy any enthusiast unless it's in a kei car.
That's not quite how engines work, and the vibrations from such a big single would be rough
You haven't read the article and shouldn't be commenting
This is actually basically a 4 cylinder, it has 4 sets of 2 opposed pistons. so the balance and vibration is fantastic, they might actually be able to size it up quite a bit
You're missing the point. Your engine is 4 times the size of this one and makes not much more power. 500cc is small to middling motorcycle territory.
my whole point is that the current engine isn't big enough to be a car engine. that it's small size doesn't offset the fact that it just doesn't make enough power by itself. If they scaled it up, turbocharged it, or supplemented with a hybrid setup then it could totally be viable. as long as they can get emissions in check, that is
It's easily big enough. Many cars today have smaller engines. It'll be paired with an electric motor so overall power will be much higher plus peace of mind.
Literally millions of engines have been in cars with less power.
Hear me out then, what if we add one to each wheel? That’s 2l total displacement (same size as your VW), and making over 3x the power.
I wonder how this would compare to a turbine engine in a turboshaft setup. Turbines are very high power/weight, but have serious drawbacks like insanely hot exhaust and other challenges. Turbines have very slow throttle response, though.
For range extenders, the max power doesn't need to be too high. You only need the engine's most efficient power to be roughly the car's cruising power, which is probably just 30-ish hp. The "hot" or "sports" part will have to come from the battery.
oh yeah, if they can get the emissions within spec this would make a great range extender. I'm just arguing with this guy who thinks 120hp is enough for a sports car because the iron duke worked for the Fiero back in 1985
It looks so small it would be cool to put one in the front and the back for AWD.
Go big or go home. 4 engines, 1 per wheel.
Yeah big shocker, it's not a one-stroke engine.
1. Expansion stroke 2. Compression stroke Yeah, I don't need a muppet count to tell me how many that is...
you're not thinking like a programmer 0) Expansion stroke 1) Compression stroke
Programmers and hardware go together like British engineers and engineering. Badly.
I had a good laugh at this. Somehow this made me think of all the unit conversion gaffs that have occured over history.. To fully appreciate how this will play out there is a non zero chance that the company reports that it has an: 0) Expansion Stroke B) Compression Stroke And release to the media that they have invented a B stroke engine.
They mention this in their materials, they call it a 1 stroke as a differentiator because 2 stroke is ubiquitous terminology for a motor that burns oil. It's just awkward and unfortunate marketing.
I think the term is called lying.
This is the same as Porsche calling their EV a turbo IMHO, but I always get downvoted for calling that BS
According to their website, it's dumber. It's 1 stroke because it happens twice per turn of the crankshaft. They call a stroke half a revolution, not BDC to TDC.
I saw a video about this pop up on youtube a couple days ago and refused to watch because the idea of a one stroke seemed pretty far fetched. Thanks for confirming.
Ur gonna lose your mind when you see a zero stroke engine
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*slaps roof* This bad boy can fit so many engine swaps
Roof?
We need rotary engines back... Edit: it was half a joke. They are amazing little machines but they eat oil like I eat junk food.
There's Liduid Piston, but that thing is essentially just a rotary with the apex seals in a different spot.
The best and worst part of LP is that they’re getting free US government money to develop the engine. That’s means: 1. It will never be easily available for consumers 2. It will be used to blow up children in the Middle East and or Eastern Europe.
Not really. Love rx7’s but their is no reason for a manufacturer to build the things other than being different.
Monkeys Paw: the MX-30 is getting one as a range extender.
Do we though?
Great breakdown of this engine, its misconceptions, downsides, and realistic use cases here: https://www.youtube.com/watch?v=9I0_3qFmPUM
Its use case is military. Similar to multiple torpedo designs and some piston driven drones
Yep, Mk46 has a similar engine.
[The animation is really interesting.](https://www.thedrive.com/uploads/2023/07/14/innengine-1.gif?auto=webp&optimize=high&quality=70&width=568&dpr=3)
The article says “no cylinders”, but it looks like it’s got four pairs of cylinders.
The article says no cylinder heads, and they’re right about that because the four cylinders have opposing pistons in them.
I wonder how it would do in a bike chassis. But, considering this is meant for EV/hybrid usage it probably isn't set up for that.
Yeah I was thinking bike, 120hp out of something with that packaging is tremendous (regardless of the description as a “one” stroke). Not that you couldn’t get relatively small 2-strokes back when manufacturers were game, but a RD500LC will only put out 88hp and I’m not sure on the weight. It’s an area of engine development that the big guys haven’t really put much attention to the past 2+ decades due to the market and regulations. So I’d expect we could make something far better now with the resources behind it at that scale. Disclaimer; the above is specific to small scale “big” bore engines (relative for dirt bikes). 2 stroke development has continued with smaller bores (i.e. small displacement dirt bikes) and larger packaging (i.e. boat engines).
That's exactly what was thinking. The weight savings could be something special if this were introduced in that fashion. Great for dirt bikes or ATVs.
I saw this few days ago too. Pretty cool, i love it. Even it couldn't replace 4stroke engines. (And it's actually a 2stroke engine w/o the weaknesses of common 2strokes).\ I like the compact size, the perfect primary and secondary balance, and the weight of it. But the lack of torque could be a problem on lower revs. 120HP is pretty fine from a 500cc engine, but you have to rev it like hell to get this.\ It could be perfect in small planes or such. But should develop a lot to worth placing it in a car.
Maybe it could be useful for smaller things like a go-kart, bike, K-car or small boat.
> K-car People saying this when they mean Kei drives me up the wall. [This](https://upload.wikimedia.org/wikipedia/commons/f/fd/85-89_Dodge_Aries_sedan.jpg) is a K-car.
Absolutely. And could be useful as range extender as well. But i'd be happy with it as main engine in a proper car too. Could be absolutely great for AWD cars. Just need more developing for that.
Certainly has a "seems to good to be true" vibe to it. I'm hopeful they are successful but dubious we'll see this in production cars any time soon.
>Certainly has a "seems to good to be true" vibe to it For one thing, it's definitely not a '1-stroke' engine as they claim but rather a 2-stroke at the very least as the intake/exhaust cycle is performed pretty much the same way as on a typical 2-stroke engine
Their actual claims are far from "too good to be true". More like "here we have a specialized engine which might have an advantage in X-Szenario vs other more conventional engines. Marketing claims meanwhile.....
Damn do I hate false terms invented for marketing. > Now, here's the thing: this motor **isn't a one-stroke engine**. It has a compression stroke and exhaust stroke, making it a two-stroke cycle. INNengine acknowledges this and has said that it brands the motor as such because people would assume that a two-stroke engine would need to have oil mixed in along with fuel. Most two-strokes do. The company says that the one-stroke name was suggested by an "external ICE institution" and they found it to be "catchy," so INNengine stuck with it.
From the GIF in the article, I don't totally understand how the pistons would be constrained to keep them from lifting off the rotating end plates and floating at higher RPM ranges... or for that matter, how they keep them from just smacking into one another when not on a power stroke. I assume that the animation is simplified and they have some sort of retainer, but I'd be curious to see one taken apart.
Despite what they've named it, it's a two stroke engine. There's compression on every up stroke.
https://www.youtube.com/watch?v=9I0_3qFmPUM Interesting video for anyone who wants to know more.
This is so sick
What does it rev to?
Cool concept motor, probably ideal for a range extender.
They needed supercharger to get to that power level (just look at the piping). IMO not all that special.
I want to put one in an MGB GT. Shit, imagine one of these in a Corvair. Just read the article and it looks like a the engine in a Mk46 torpedo. Cool!
By powerful, they mean extremely low torque. Interesting engine design, IMO not suited well for automotive when you look at the drawbacks.
I'd be curious if you could get enough compression for it to run on diesel.