[00:02] outboard motor is here a big thanks to Yamaha for bringing me out to SEMA to check it out and for sponsoring this video where we'll Deep dive into the fascinating engineering involved to make this concept a reality after speaking
[00:16] we're going to cover the following questions in this video first what is hydrogen combustion second how does yamaha's prototype boat work third what
[00:28] kind of range can a hydrogen boat get and fourth what are the unique challenges for hydrogen boats now before we get into it I want to be very clear that this is a prototype build an engineering proof of concept for
[00:40] hydrogen combustion which is one of many potential solutions for reducing the Transportation but obviously not the only solution Yamaha is looking into all kinds of different Technologies whether that's battery electric fuel cell
[00:55] sustainable fuels or even hydrogen combustion so while that is what this spefic spefic video will focus entirely on know that Yamaha is exploring multiple options seeing what technology might work for different applications so
[01:08] just as an example this prototype build is based on a 26t offshore fishing boat which normally comes with a 107g gasoline fuel tank if you were to try and go electric even if you assume the electric powertrain was three times as
[01:23] efficient that mean you need a 1,200 KW battery pack to match the range and that battery could could weigh about 13,000 lb with current Pack level lithium ion battery technology that's about 4,000 lb
[01:37] more than the entire gasoline version of this boat in just batteries alone so it'd be super expensive and crazy heavy making it obviously challenging for this kind of long range application all right so why might hydrogen be a solution well
[01:52] several reasons hydrogen combustion has virtually no carbon emissions hydrogen fuel is very lightweight and hydrogen combustion makes use of existing technology so the big perk of using hydrogen as your fuel source is that the
[02:05] main emission of combusting that hydrogen is going to be water so if you don't have carbon in the fuel well then the emissions from that fuel are not going to have carbon in them unlike gasoline of course which has carbon in
[02:17] the fuel and thus CO2 is a big part of the emissions the combustion process is very similar to the same four strokes you're used to in a gasoline engine but with an altered cylinder head and the hydrogen fuel in ction system but in
[02:31] kinds of engines boats are already running on today direct injection is one key piece of technology used which plays an important role with hydrogen combustion engines like the one that
[02:45] injection is really important for hitting power targets so why is that well with port injection you're going to have a lot of space that is just taken up by that hydrogen so unlike gasoline hydrogen takes up a ton of space and
[03:02] Atmospheric pressures so if you're dumping in that fuel in the port and then relying on this piston to pull in the air and fuel well hydrogen has about the air and fuel well hydrogen has about a 2.4 to1 stoky metric air fuel ratio by
[03:14] volume meaning Once you pull in all that air only about 70% of that space is actually going to be air and about 30% of that space is the hydrogen fuel so if have within this cylinder well you're reducing the amount of oxygen that you
[03:29] can then used to react with that hydrogen and make more power so you're instantly taking a big Power Hit because you're limited on how much air you can pull in within that cylinder because hydrogen takes up so much space you also
[03:41] of course have the risk of backfire since you have hydrogen in that intake manifold now with direct injection you can pull in that 100% atmospheric air within that cylinder and then you can use direct injection and pressurize and
[03:54] force in additional hydrogen within that power especially in these naturally aspirated applications and of course within the cylinder much lower risk of
[04:08] having backfire all right so let's move on to the actual prototype build in this case Yamaha is the brains behind the combustion engine Rous has engineered the fuel system and regulator has provided and adapted their 26t offshore
[04:21] hole to accommodate the hydrogen fuel tanks so how does it all work all right so with this boat there are three high pressure large hydrogen tanks they are storing that gaseous hydrogen at 700 bar again hydrogen takes up a lot of space
[04:36] at atmospheric pressure so you have to pressurize it to get more hydrogen in a pressurize it to get more hydrogen in a smaller space about 10,000 PSI so from these tanks they all run into a common collector you of course will have a shut
[04:48] can isolate individual tanks or if you need to fill the tanks uh and then from there you're at 700 bar you go through a regulator and you drop that down to 100 bar so that is the injection pressure for the fuel injection system the direct
[05:03] injection system and because your tanks are pressurized you're not using a fuel pump all of the pressure to inject that fuel is coming from the pressure of these tanks and then being injected into those cylinders at 100 bar now these are
[05:18] in parallel all of them collecting with a common collector here because if you were to have any issues with one tank you don't want it to then cut off to this and you had a problem with one tank for some reason well you can still
[05:31] use these tanks shut this one off they all go to a common collector and you can use all three tanks simultaneously to supply that fuel to the V8 engine in this case A 5.6 L V8 engine that this is
[05:44] based on which the gasoline version is making about 450 horsepower the challenge here of course is trying to match that performance while making minimal changes to the combustion design so hydrogen is capable of making similar
[05:58] challenging to do that when you're starting with a gas engine and then to make in order to make that whole cylinder head here and of course that different fuel injection system as for
[06:12] the hole there are some serious modifications required in order to accommodate the hydrogen fuel tanks usually you're relying on the hole as well as the grid of stringers and bulkheads to make up the structural
[06:24] rigidity of the boat in this case because the stringers and bulkheads need to be adjusted to make room for the hydrogen tanks the deck of the boat is now used as a more structural member to increase the rigidity to match the same
[06:37] requirements as the gasoline version of this boat and of course adding all of these tanks does add weight while the hydrogen fuel is lighter than gasoline the boat weighs over 600 lb more with the new fuel system all right looking at
[06:52] these tanks what kind of range can we expect from this boat now it's important to recognize that there are currently two versions of this prototype that are built there's the showbo as we see here for use at trade shows like SEMA and an
[07:05] actual demo boat that's being used by Yamaha for internal testing as it's still under development Yamaha has not released any official numbers surrounding power output or range but this is engineering explained so of
[07:18] course we're going to try and calculate what the actual range is and so that we're perfectly clear these are my numbers based on my assumptions not numbers provided by Yamaha but I'm I'm pretty confident I can get close so
[07:32] let's get into it all right so first let's look at the production gasoline gas version of this boat is the regulator 26xo with a Yamaha 450 horsepower motor so this boat has a gasoline fuel tank of 107 Gall and you
[07:50] can look at the fuel economy versus RPM curve and find this peak right here exists at about 4,000 RPM this thing will get 1.9 4 m per gallon so multiply the number of gallons by your MPG and we get a total range for the gas boat at
[08:06] about 27.6 miles all right so now looking at the Prototype we need to figure out how much hydrogen we have stored between these three hydrogen tanks luckily there's a label on the tanks so we can
[08:19] look up the specs for this tank which looks to be about 240 L and they store hydrogen at 700 bar or 10,000 PSI all right so a 240 l tank storing hydrogen
[08:31] right so a 240 l tank storing hydrogen at 700 bar is going to give us about 9.8 kg of hydrogen however these tanks are effectively empty when they reach 100 bar because we don't have a fuel pump and we're relying on that pressure for
[08:45] injecting into the engine so we have to subtract the amount of hydrogen that will be stored at 100 bar in these tanks so 100 bar for each tank is going to so 100 bar for each tank is going to give us about 1.9 kg of hydrogen so we
[08:58] have three tanks Each of which gives us a usable 7.9 kg or a grand total of about 23.7 kg of hydrogen stored on board now
[09:11] hydrogen has about the same energy equivalency as a gallon of gas 1 kgam of hydrogen is about equivalent to 1 gallon of gas so if we take 23.7 kg of hydrogen and we divide that by 107 gallons of gas and we multiply
[09:29] by 107 gallons of gas and we multiply that by our total range of 27.6 mil that that by our total range of 27.6 mil that gives us a hydrogen fuel range of 46 miles all right so obviously range is a very serious challenge we're at less
[09:42] than a quarter of the gasoline boats range and just to back this math up if we want to minimize assumptions with our calculations we can simply look at energy equivalency to see how much hydrogen the boat would need to store in
[09:55] order to match the amount of energy stored with gasoline now again a kilogram of hydrogen is about the energy equivalent of 1 gallon of gas so if the boat has 107 gallons of gas well it's going to need about 107 kg of hydrogen
[10:10] to have an energy equivalency now hydrogen stored at 700 bar has a density of about 40 kg per M cubed meaning you're going to need you're going to need 2.67 5 m cubed of hydrogen stored at 700
[10:25] 2.67 5 m cubed of hydrogen stored at 700 bar in order to get 107 kg of hydrogen or or about a 707g fuel tank all right so obviously that is a massive fuel tank so how can we improve the range of this boat
[10:39] assuming it runs on hydrogen combustion okay so the obvious answer is you use more tanks right well the challenge is you need a lot of Tanks over 13 tanks of what we see here on this boat in order to make the equivalent range of the
[10:53] gasoline version also a simple obvious idea use a hydrogen pump right because you have all that fuel just sitting in these tanks at 100 bar that you can't use because you don't have a fuel pump so that would give you an additional 20%
[11:06] usable hydrogen if you went with larger diameter tanks if you go from about half diameter tanks if you go from about half meter to about 7 m so a 200 mm increase in the diameter of these tanks you can effectively double how much hydrogen
[11:18] tank you got to put it somewhere but an efficient way of doing it also you could use conformal tanks so this is a more space efficient way of putting you know cylinders within a rectangular area so if you just have one big cylinder
[11:31] there's a lot of wasted space around that Circle that you could be using so conformal tanks take advantage of that and you use smaller cylinders all connected together to make use of that extra space again giving you a benefit
[11:43] of about 25% increase in hydrogen you could use higher pressure hydrogen uh there are stationary storage tanks that are holding pressurized gaseous hydrogen at 950 bar that gives you an increase of about 25% and then there's also liquid
[11:57] hydrogen which over this gas I hydrogen at 700 bar liquid hydrogen is going to allow you to store 75% more hydrogen within the same space now there are a lot of practical reasons why liquid hydrogen isn't used which I have other
[12:12] all comes down to the fact that liquid hydrogen needs to be stored at- hydrogen needs to be stored at- 253° C which alone is difficult but also means that hydrogen will eventually have to be vented out of the vehicle wasted
[12:27] entirely if you don't use it because starts to boil and the tank pressure Rises rapidly ultimately one of the biggest challenges with hydrogen is where do you put it because despite the fuel not weighing much it takes up a lot
[12:39] of space that means anywhere you store these hydrogen tanks well you're storage space from the boat reducing cargo space and practicality but the challenges don't end there there's
[12:52] engineering required so I want to dive a little deeper into the tanks as well as discussing hydrogen Le something I did not know about these hydrogen tanks is that they actually expand a significant amount as you
[13:06] pressurize them with that hydrogen they can grow as much as about 50 mm we're talking about about a 2 m tank in length and they can grow about 30 mm in diameter so this is a significant increase in the size of that tank which
[13:21] you of course have to accommodate for so one of the ways is you're only going to fix it for the mounting on one side allow that tank to grow in the lengthwise direction here and then have a collar that holds it in place that
[13:33] that tank can then slide within the collar also they don't want this to be a stressed member of the boat so these collars are going to be able to Pivot so that you're not stressing this tank itself another really interesting
[13:46] challenge is that hydrogen is a very small molecule and it doesn't like being stored so these hydrogen tanks have permeation standards that they have to meet ensuring a minimal amount of hydrogen escapes but the fact remains
[13:59] that some hydrogen will escape now these permeation rates are really low so from a range standpoint it's really not something you need to think about but you don't want hydrogen accumulating within the hole of the boat hydrogen of
[14:13] course is flammable so as you have this hydrogen permeate out of these tanks you ventilation to get rid of that and let it Escape so for example within this bat there are sensors that detect the hydrogen percentage within the air
[14:27] within that hole and so so they will warn the driver when hydrogen getss to about 1% and they will shut down the boat if hydrogen gets to about 2% now this is below when hydrogen is flammable so you don't have to worry about it yet
[14:39] at these percentages but you of course need to be aware of these problems if you do have a hydrogen leak somewhere now you have ventilation within this hole in order to purge so on Startup for example it can Purge the entire air
[14:52] within that hole in a matter of seconds so you purge out all that air then you worry about hydrogen accumulation within that hole on Startup and causing any scene so overall it's a fascinating
[15:05] project that Yamaha is working on and it'll be interesting to see the results further developed a big thanks to Yamaha sponsoring this video If you all have any questions or comments feel free to
[15:17] any questions or comments feel free to leave them below thanks for watching