[HN Gopher] Company builds 500cc 'one-stroke' engine
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       Company builds 500cc 'one-stroke' engine
        
       Author : throwaway28203
       Score  : 93 points
       Date   : 2023-07-15 16:42 UTC (6 hours ago)
        
 (HTM) web link (www.thedrive.com)
 (TXT) w3m dump (www.thedrive.com)
        
       | LispSporks22 wrote:
       | Would this be good in a bike? Would it likely be more power than
       | say my R1?
        
         | Enginerrrd wrote:
         | I don't think it'd be very good.
         | 
         | It has no torque on the low end so you'd have to set idle
         | really high to get useful low range performance.
         | 
         | This type of engine is great for its intended application
         | though: A steady-state range extender/generator.
         | 
         | Now, at higher revs, it might be pretty sweet.
        
           | Ancapistani wrote:
           | Yep, you'd have to run it at high RPM, like a rotary.
        
       | danielovichdk wrote:
       | Would make a great boat engine for smaller leasure crafts and
       | sail boats.
        
       | s17n wrote:
       | In case you're wondering:
       | 
       | "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 close to he bottom of the article)
        
         | dreamlayers wrote:
         | So, how do they lubricate it?
        
           | jacquesm wrote:
           | Like any other engine with a separate oil system.
        
           | Tuna-Fish wrote:
           | The same as any other engine that doesn't mix oil into its
           | fuel.
           | 
           | Lubrication in fuel vs lubrication using a separate system
           | and 2-stroke vs 4-stroke are two entirely separate
           | engineering decisions, that are in no way tied to each other.
           | It's just that the most common types of 2-stroke engine use
           | lubricant oil mixed in fuel, and the most common types of
           | 4-stroke engines don't, and so they concepts are thought to
           | be related to each other by most people who don't know much
           | about engines.
        
             | hatsunearu wrote:
             | 2-stroke engines often go into handheld tools or dirt bikes
             | that can't explode when you turn it upside down (at least,
             | immediately), and since it eliminates the oiling system,
             | premix is often chosen for these.
             | 
             | 2-stroke engines also have great power densities (at the
             | cost of fuel efficiency), which means those two often go
             | hand-in-hand.
        
         | userbinator wrote:
         | _because people would assume that a two-stroke engine would
         | need to have oil mixed in along with fuel_
         | 
         | That suggests most people don't know about 2-stroke diesels,
         | although I suspect much of the older population (at least in
         | North America) have probably heard or been on a vehicle that
         | uses one.
        
           | caseyohara wrote:
           | Also plenty of (gasoline) two-stroke engines use oil
           | injection so you don't have to use premix, namely any machine
           | where you'd typically get your fuel straight from the pump
           | like a snowmobile or a dual sport motorcycle, back when those
           | were still two-stroke.
           | 
           | I had a 1983 Yamaha DT-80 (little enduro dirt bike) that had
           | an oil reservoir so you could use pump gas.
        
             | jacquesm wrote:
             | Those are pretty nasty for bystanders though.
        
       | throwaway28203 wrote:
       | Immediately Installs It in a Miata
        
         | rolph wrote:
         | https://yt.artemislena.eu/watch?v=-evhsWLWlkY [video]
        
       | FollowingTheDao wrote:
       | Man, a smaller version of these would be awesome in motorcycles
       | and scooters. Wonder what the MPGs are....
        
         | [deleted]
        
       | criddell wrote:
       | I wonder if this would be a good engine for an airplane?
        
         | ben_bai wrote:
         | In theory, yes. But especially the single engine aircrafts are
         | very set on old but reliable engine design, for reasons.
        
         | Tuna-Fish wrote:
         | In terms of power curves and power to weight, absolutely. But I
         | would be really unhappy taking off in a plane that uses a cam
         | engine. Those are not historically known for their great
         | reliability.
        
       | ksaj wrote:
       | Something to notice in the line drawing: The rear is powered by
       | an electric motor. I assume that's to get it moving in the first
       | place before there's enough momentum for this engine to keep it
       | going.
        
         | watson wrote:
         | I would assume so, yes. This is exactly how regular motors get
         | started, unless you have one of those old-timy cranks you had
         | to manually turn to get the motor running
        
       | incomplete wrote:
       | of COURSE they put it in a miata. :)
        
       | rolph wrote:
       | actually a two stroke, 2 opposing pistons in a common cylinder
       | cycling through compression stroke-combustion-power stroke. no
       | connecting rod to bend or break, and large cams replacing the
       | crankshaft
       | 
       | https://www.thedrive.com/uploads/2023/07/14/innengine-1.gif?...
       | 
       | [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.]
       | 
       | the goal seems to be a hybrid ehicle that places more duty
       | reliance on electric propulsion, but keeping the long range
       | capabilities of petrol fuel in a combustion-over-electric design.
       | 
       | [adndm] this is 120HP in 500cc displacement, which is superbike
       | engine stuff
        
         | userbinator wrote:
         | _this is 120HP in 500cc displacement, which is superbike engine
         | stuff_
         | 
         | The real question you should be asking when you see
         | suspiciously high power densities is "for how long?"
         | 
         | A car and a truck engine can have the same HP rating, but the
         | former is not going to last very long producing that power
         | continuously, while the latter is essentially designed to spend
         | most of its time at full power.
        
         | ksaj wrote:
         | Indeed. My old bike had 1400cc and was rated at only 94 hp.
        
           | jacquesm wrote:
           | 'old' may have something to do with it here, engine tech has
           | seen all kinds of improvements over the last two decades
           | resulting in tiny engines with ridiculous levels of output
           | while still having reasonable life span. A pretty common
           | small car engine that has .9 L displacement and a turbo
           | yields 105 HP, that's 120 HP/L, vs 67 HP/L for your bike. A
           | few years ago I had a 660 CC 4 cylinder engine in a car that
           | did 67 HP so that's about 100 HP/L.
           | 
           | This engine is pretty clever, it avoids one nasty problem of
           | swashplate drives and their cousins: the piston travel is
           | only half here of what it would be otherwise. But there is a
           | lot of extra complexity.
        
             | brucethemoose2 wrote:
             | The Ariel Atom V8 did ~160hp/liter in a 3L NA engine.
             | 
             | I'm sure its pretty high strung, but its also older and
             | more "conventional" than exotic supercar engines.
        
               | jacquesm wrote:
               | The Atom is an absolute beast.
        
             | windexh8er wrote:
             | We should probably call a spade a spade here. This is a
             | 2-stroke motor. In today's powersports world it's normal
             | for a factory 650cc motor to be putting out over 135HP.
             | It's not impressive in terms of the performance to engine
             | size and, as I mentioned in another comment, this engine
             | will be extremely weak on the torque side of the equation
             | which will make those ponies virtually useless.
        
               | jacquesm wrote:
               | That's fair, for a two stroke it isn't substantially
               | better than what's out there. As for weak on the torque,
               | for a generator that may not matter all that much. What
               | I'm more curious about is the powerband, in other words
               | how wide the RPM range is over which it produces max
               | power. If that range is wide it might be a very useful
               | engine (because you can simply couple it with an
               | appropriate gearbox for torque), if it is very narrow
               | then it really only will work well as a generator
               | producing high frequency AC.
               | 
               | That's one reason why specialty generator engines tend to
               | run with very sharp cams on the camshafts: they only need
               | to work in a very narrow RPM range and opening them
               | earlier or later is just going to waste fuel so for
               | maximum efficiency you want the valves to be open _just_
               | long enough to take in enough air or to exhaust the
               | expended fuel /air mixture.
               | 
               | edit: apparently this engine also has a super charger,
               | which isn't quite 'atmospheric'.
        
         | windexh8er wrote:
         | > this is 120HP in 500cc displacement, which is superbike
         | engine stuff
         | 
         | HP-wise, maybe. But the reality is this is not a performant
         | engine you'll see replacing high performance 2 or 4 stroke
         | motors anytime soon.
         | 
         | First is that the company has lied a lot in their marketing.
         | They imply that the motor is naturally aspirated and then show
         | a car, with said plant running a very obvious supercharger.
         | They also lie about the motor type - there is no viable
         | 1-stroke motor and there likely never will be based on the laws
         | that govern our planet. They even admit to their own lie in the
         | name of marketing (a non-oil burning 2-stroke is not a 1-stroke
         | by default).
         | 
         | The real reason this motor will not touch a comparable
         | superbike cc-to-cc is that this motor has no claimed torque
         | specs. It really doesn't matter at all if they're able to put
         | out 120HP in 500cc if it has low torque. And we know it has low
         | torque based on the fact that this motor has no crankshaft, and
         | therefore the mechanical advantage that adds.
         | 
         | I currently have 650, 800 and 850cc 2-stroke motors today that
         | have similar HP-to-cc today compared to the 120HP they've
         | claimed from 500cc. The difference is that all these motors
         | have the torque required for driving performance.
         | 
         | While I would love to see something bridge the gap of small
         | heavy 4-stroke vs light oil burning 2-stroke this is,
         | unfortunately, not it.
        
         | merth wrote:
         | why I feel like this would put pressure on one side of cylinder
         | block due to non-linear force against bottom wave-plate and
         | cause wear and tear?
        
           | timlarshanson wrote:
           | Agreed.
           | 
           | Also, how does it get started? Seems like the only force
           | pushing the piston against the axial cam is the fuel
           | explosion. (Perhaps extra springs to retract the piston for
           | intake?)
        
             | Ancapistani wrote:
             | Presumably an electric starter, much like a traditional
             | engine - only it'll turn the driver shaft instead of a cam
             | shaft.
        
             | pengaru wrote:
             | > Also, how does it get started? Seems like the only force
             | pushing the piston against the axial cam is the fuel
             | explosion. (Perhaps extra springs to retract the piston for
             | intake?)
             | 
             | In lieu of combustion you still have the air spring rebound
             | from the compression... (at least until the exhaust opens)
        
       | Animats wrote:
       | That's neat.
       | 
       | This is a type of axial engine, a cam engine.[1] People have been
       | trying designs along this line since at least 1926. A recent
       | version was from Axial Vector Engine, which was pushing their
       | stock around 2006 and is now gone.[2]
       | 
       | The problem with this class of designs is that they apply large
       | forces to small parts. The most likely source of trouble is the
       | bearings of those little wheels at the base of each piston. Those
       | have to take the full force of the explosion on each cycle. That
       | doesn't mean it's impossible, but it means it's a long way from
       | the first running engine to one with a long, useful, low-
       | maintenance life.
       | 
       | [1] https://en.wikipedia.org/wiki/Axial_engine
       | 
       | [2]
       | https://web.archive.org/web/20090208215443/http://www.axialv...
        
         | Justsignedup wrote:
         | also noted, that they don't have that lever like standard
         | pistons do, so torque is an issue.
        
           | pedrocr wrote:
           | If it's putting out the power you need with good efficiency
           | just gear it for whatever torque you want for the
           | application.
           | 
           | The idea that torque and power represent different qualities
           | out of an engine comes from manufacturers quoting just peak
           | torque and peak power, giving you two different points on the
           | torque and power curve. A complete torque or power curve is
           | much more useful. Either works and which is just a matter of
           | preference as you can just calculate the other from the same
           | data.
        
           | Ancapistani wrote:
           | Torque isn't an issue if it isn't pushing a drivetrain, but
           | an inverter generator to charge the electric drivetrain.
           | 
           | That would also lower the forces applied to the piston roller
           | bearings, which should greatly improve reliability.
        
             | ben_bai wrote:
             | Yes those tiny new engines (also liquidpiston engine) would
             | make a good range-extender for electric drivetrains, also
             | thinking semi-trucks and big equipment. Wherever you need
             | big torque/power to get going, but once rolling 35hp is
             | enough to keep rolling.
        
       | c2h5oh wrote:
       | They admit it's two stroke, but they use that name because they
       | have no oil in fuel and "it's cool".
       | 
       | It's small, lightweight, perfectly balanced but has low torque so
       | it's not a best fit for cars. Would be great for generator.
        
         | sethhochberg wrote:
         | They're pretty explicitly marketing it as a "range extender"
         | for hybrid electric vehicles. In the mockups in the article it
         | seems like they don't have a traditional gearbox, so it sure
         | looks like they're intending to suggest running it as a
         | straight-up electrical generator even when mounted in a car.
         | Neat application of the concept. Diesel locomotives have worked
         | this way for a long time.
        
         | seiferteric wrote:
         | Considering the negative associations with two-strokes (noise
         | and emissions) it makes sense to try and distance themselves
         | from it if it does not have these properties.
        
         | cperciva wrote:
         | _Would be great for generator._
         | 
         | That was my first thought too -- this design seems simpler and
         | correspondingly less prone to failure than most engines, which
         | would make it well suited for emergency use.
        
       | djaychela wrote:
       | While the actual method of connection between pistons and the
       | lobed plates seems new, opposed piston engines have been around
       | for a long time, so I'm not sure this is quite as new as the
       | article appears to make out [1]. I instantly thought "deltic"!
       | 
       | [1] - https://en.wikipedia.org/wiki/Opposed-piston_engine
        
         | jacquesm wrote:
         | That's a variation on the swash plate drive:
         | 
         | https://en.wikipedia.org/wiki/Swashplate
         | 
         | I like theirs better than an actual swash plate because you can
         | pull all kinds of timing tricks by shaping the lobes just so,
         | and it looks easier to lubricate.
        
       | gfody wrote:
       | looks like the dynacam, whatever happened to that?
        
       | jauntywundrkind wrote:
       | 120 HP is 88kW. You could shrink this considerably & still have a
       | very nice range extender. (Edited: proper conversion)
        
         | sitkack wrote:
         | Many cars use only 20kw to go highway speeds, imagine if this
         | could shrink to 1/8th its current size.
        
         | fuzzy2 wrote:
         | That conversion is the wrong way around. 120 HP is roughly 88
         | kW. The point still stands, of course. If it indeed can be
         | shrunk further while remaining efficient.
        
       | russellbeattie wrote:
       | Here's a great deep dive into the engine, explaining the pros and
       | cons: Yes it's simpler and more compact, but the lack of crank
       | shaft means that it doesn't benefit from the lever effect of the
       | shaft so it doesn't have as much torque.
       | 
       | https://youtu.be/9I0_3qFmPUM
        
         | hammock wrote:
         | Then it's perfect for a hybrid vehicle that uses electric when
         | torque is needed
        
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