DIY parallel hybrid - anyone done it?

[bluenomads]

I already have two 135hp diesels on our cat.
I want to put in a parallel hybrid on one side, but all the existing systems (like hybridmarine) supply the matched diesel whereas I want to use our existing one.
Has anyone done this before to a mid-size inboard diesel?
Please note, if you ask "why", I'll just ignore you: the reasons don't matter, I'm only after whether anyone has done it, or has ideas on how to do it better/well.
I don't need asking why do I want to or told why it won't work. Thank you .

By parallel hybrid, I mean an electric motor next to/above the drive shaft allowing continuing diesel power, or electric-only power, to the same drive shaft.
Now the reduction gearbox on the existing diesel is mated directly to the motor (2:1), and (I assume but haven't checked) a thrust bearing. So it wouldn't be possible to insert a drive belt from the electric to in between the motor and gearbox to reuse the gearbox. But that means I can't use a reduction gearbox from the electric on-shaft either as then I'd have double reduction for the diesel.

So I'd need motor + controller + gearbox (2:1 reduction) + ability to run a tensioned belt or chain to the existing shaft. Oh, and of course the other parts of the system I'll ignore for now (batteries, throttle, etc.). Many of the controllers permit "regen" from the controller, so I shouldn't need a clutch on the shaft to decouple the electric when the diesel is running. Existing shaft speed is 500-1200rpm.

At the moment I'm thinking of playing with the thunderstruck motor, sevcon 48 controller and reduction gearbox. But I'm a bit stuck on the best way to attach a chain or tensioned belt to the 1.5" shaft - any ideas?

[Matt Johnson]

Why wouldn't you just put a chain sprocket (belt pulley) on the shaft the correct size for your 2:1 and drive that from the electric motor? This would eliminate the gearbox and the coupling.

Just make sure your diesels gearbox can be spun in neutral without causing issues.

Matt

[Q Xopa]

Originally Posted by bluenomads

I already have two 135hp diesels on our cat.
I want to put in a parallel hybrid on one side, but all the existing systems (like hybridmarine) supply the matched diesel whereas I want to use our existing one.
Has anyone done this before to a mid-size inboard diesel?
Please note, if you ask "why", I'll just ignore you: the reasons don't matter, I'm only after whether anyone has done it, or has ideas on how to do it better/well.
I don't need asking why do I want to or told why it won't work. Thank you [emoji2].

By parallel hybrid, I mean an electric motor next to/above the drive shaft allowing continuing diesel power, or electric-only power, to the same drive shaft.
Now the reduction gearbox on the existing diesel is mated directly to the motor (2:1), and (I assume but haven't checked) a thrust bearing. So it wouldn't be possible to insert a drive belt from the electric to in between the motor and gearbox to reuse the gearbox. But that means I can't use a reduction gearbox from the electric on-shaft either as then I'd have double reduction for the diesel.

So I'd need motor + controller + gearbox (2:1 reduction) + ability to run a tensioned belt or chain to the existing shaft. Oh, and of course the other parts of the system I'll ignore for now (batteries, throttle, etc.). Many of the controllers permit "regen" from the controller, so I shouldn't need a clutch on the shaft to decouple the electric when the diesel is running. Existing shaft speed is 500-1200rpm.

At the moment I'm thinking of playing with the thunderstruck motor, sevcon 48 controller and reduction gearbox. But I'm a bit stuck on the best way to attach a chain or tensioned belt to the 1.5" shaft - any ideas?

Havent done it yet either, but going down pretty much the same road.
Thunderstruck also do their toothed belt reductions. Valence U27-24XP
Has the tensioner setup. Sounds like what youre asking about.
Sounds like youre already expecting the onslaught of- whys, that'll never work bla blas.
Im sure they wont disappoint.
Good luck.

[bluenomads]

Sigh. Of course you're right!

That eliminates the second reduction gearbox entirely.

The gearbox is a Hurth 450A2 (same as "ZF 45 A" I think). I'm led to believe it can freewheel without issues (anyone know?!)

[bluenomads]

Originally Posted by Q Xopa

Havent done it yet either, but going down pretty much the same road.
Thunderstruck also do their toothed belt reductions. Valence U27-24XP
Has the tensioner setup. Sounds like what youre asking about.
Sounds like youre already expecting the onslaught of- whys, that'll never work bla blas.
Im sure they wont disappoint.
Good luck.

Thanks! I'll look into the toothed version.
Good to hear the road is starting to be well trod .

[valhalla360]

Love it...you aren't allowed to ask about design parameters (ie: why you are doing this) but tell me it will work and how to do it.

[Q Xopa]

The OP is asking for practical assistance. Opinions not so much.

The title 'DIY Parallel- anyone done it?' seem reasonably self explanatory.

I can respect that.

Of course Opinions are standard fare for Forums.

He's most likely busy trying to figure out where to source components how to put this together. He's not so interested in wasting time debating why he has chosen the concept. He's obviously already spent his time researching and made his decision. It's wasting time having to repeatedly rehashing and trying to explain and justify that decision.

When he works it all out, I'm sure he will be only too happy to share his experiences. Let's let him work it out first, and assist if and when we can.

The websites he mentions 'hybridmarine' and 'thunderstruck' give a pretty good description of-
why one would want to do this,
how it works, and
how to do it.

But of course we are all free to start our own thread if we are interested in discussing the whys and wherefores of the concept.

[Sailmonkey]

You need to tread carefully tensioning a belt against the shaft.

The shaft is supported on one end by the transmission, the other by the cutlass. Adding belt tension can/will adversely effect alignment.

But, if you put a custom built shaft spacer that just so happens to be drive sprocket between the shaft and the gear you’ll eliminate most of the tension worries. Not all, but most.

[Shaunskie]

Originally Posted by Sailmonkey

You need to tread carefully tensioning a belt against the shaft.

The shaft is supported on one end by the transmission, the other by the cutlass. Adding belt tension can/will adversely effect alignment.

But, if you put a custom built shaft spacer that just so happens to be drive sprocket between the shaft and the gear you’ll eliminate most of the tension worries. Not all, but most.

I have NOT done this but have done all sorts of strange projects on similar equipment. Having had a look around some similar ideas, here's a small pointer that you may wish to consider, what Sailmonkey says it absolutely correct but to mitigate headaches later and something that would be relatively simple to do is to put a plumber block in next to / near to your additional drive pulley /sprocket you will have to pull the original coupling off the shaft anyway to slide on the the pulley / sprocket, so slide a bearing on at the same time and built a support to suit with jacking bolts in a convenient location. Food for thought, I hope you have fun and success let us know how it goes.

[tmason]

Beta Marine did/does one with an integral motor between the engine/trans, try picking their brains.


For supporting the shaft, you could use a pillow-block bearing next to where you put the shaft pulley assuming you have something to mount it on - build a mount from wood/glass?


Have fun!

[Q Xopa]

Tensioning against the driveshaft is a valid comment.

Although as stated it could alter alignment, I would think more radial force on the cutlass bearing is probably more of a worry.

Actually I'm generally not overly convinced that engine to prop shaft alignment is usually such a concern. Of course this will vary from installation to installation.

Engines flop around on their floppy rubber mounts with different power settings or even rock as the boat is rolling around in a seaway. So which Engine natural position do we set up the alignment to? Of course its with the engine not running. It's not going to sit in the same position at cruise power, max power are all also going to be different. Ok how much our individual engine installations change may be a little or may be more. Of course its always better to give it a fighting chance and start close. My misguided thinking is our engines would be best aligned in the 'Cruise' position, where we mostly spend most of our prop spinning time. The reality is its not easily practical and probably matters little.

However, it looks to me (I could be wrong), that the Thunderstruck tooth belt reductions *https://www.thunderstruck-ev.com/gea...?sef_rewrite=1), look to have a bearing where the prop shaft runs through, presumably for just this reason.

They also state on the page for that reduction unit that it "It's thrust protection to isolate the motor from axial propeller forces ". Apart from being another bonus to help retain your propshaft and take additional strain off the engine mounts, it also tends to indicate a bearing to handle both radial and in this case also axial loads.

So getting back to eng to prop shaft alignments again. A reduction unit, in this example, will double your required alignments.
1. Eng to reduction coupling alignment, and
2 Reduction coupling to Prop shaft alignment.

Sorry to go off on a bit of a, hopefully related, tangent.

[Lancerbye]

I have a twin engine motorsailer and have thought of doing this to one side for some time. My reason is to slow the boat down for trolling speed of 1.5 to 2 knots. I usually only run one engine while cruising at 6.5 to 7 knots. I had planned to use a hydraulic motor but as electric systems become more readily available I am looking at electric. Using a rear wheel sprocket from a motorcycle and inserting it between the two halves of the shaft coupling. The centre of the sprocket would be machined to fit over the alignment lip of one side with a ring welded to the other side fulfilling the coupling alignment requirements. A key way may have to be added and the four coupling bolt holes. This will increase the shaft outward position by 1/4 to 3/8 in. depending on the source of the sprocket. Using a chain and sprocket system will require less tensioning than a belt system as they can run fairly loose.

Right now at 550rpm one one engine I am still doing 4 knots with a 2:1 reduction.

[Q Xopa]

Originally Posted by Shaunskie

I have NOT done this but have done all sorts of strange projects on similar equipment. Having had a look around some similar ideas, here's a small pointer that you may wish to consider, what Sailmonkey says it absolutely correct but to mitigate headaches later and something that would be relatively simple to do is to put a plumber block in next to / near to your additional drive pulley /sprocket you will have to pull the original coupling off the shaft anyway to slide on the the pulley / sprocket, so slide a bearing on at the same time and built a support to suit with jacking bolts in a convenient location. Food for thought, I hope you have fun and success let us know how it goes.

Can you explain what you are calling a 'plumber block' please? I'm not familiar with that term. I think you are talking about what I call a 'pillow block bearing support'. Tmason also mentions them, i think we are all talking about the same thing?

'Jacking bolts' again, not quite sure of your terminology but I think you are talking about the bolts that secure the shaft bearing 'pillow block' support housing to the hull (or some other convenient support structure).

I think we are all talking about the same thing?

Next question, if I may, seeing you have done some of this sort of thing. Any ideas where a suitable 'dog' (toothed) clutch might be sourced? Manual operated is probably ok, but if they are 'reasonably' enough priced maybe even electrical.

Like this -


or something like it.

Thanks.

[lordgeoff]

Originally Posted by bluenomads

I already have two 135hp diesels on our cat.
I want to put in a parallel hybrid on one side, but all the existing systems (like hybridmarine) supply the matched diesel whereas I want to use our existing one.
Has anyone done this before to a mid-size inboard diesel?
Please note, if you ask "why", I'll just ignore you: the reasons don't matter, I'm only after whether anyone has done it, or has ideas on how to do it better/well.
I don't need asking why do I want to or told why it won't work. Thank you .

By parallel hybrid, I mean an electric motor next to/above the drive shaft allowing continuing diesel power, or electric-only power, to the same drive shaft.
Now the reduction gearbox on the existing diesel is mated directly to the motor (2:1), and (I assume but haven't checked) a thrust bearing. So it wouldn't be possible to insert a drive belt from the electric to in between the motor and gearbox to reuse the gearbox. But that means I can't use a reduction gearbox from the electric on-shaft either as then I'd have double reduction for the diesel.

So I'd need motor + controller + gearbox (2:1 reduction) + ability to run a tensioned belt or chain to the existing shaft. Oh, and of course the other parts of the system I'll ignore for now (batteries, throttle, etc.). Many of the controllers permit "regen" from the controller, so I shouldn't need a clutch on the shaft to decouple the electric when the diesel is running. Existing shaft speed is 500-1200rpm.

At the moment I'm thinking of playing with the thunderstruck motor, sevcon 48 controller and reduction gearbox. But I'm a bit stuck on the best way to attach a chain or tensioned belt to the 1.5" shaft - any ideas?

Sorry. Cant help myself.
Why?
It won't work.

[tmason]

Come to think better of it, as Q Xopa mentioned, the engine is wobbling around so the pillow block, yes, that is one in the picture, will probably hold the shaft too rigidly and cause other problems - keep experimenting - Luddites would have us all living in mud huts!