DIY parallel hybrid - anyone done it?

[johnwilde]

Thanks alaskanviking,

So are you saying mount the pulley for the motor on the section of shaft between the two CV joints on the Aquadrive? I think mine is covered by some bellows, as shown in the photo, but that is a detail.

I would assume that typically a CV joint is to allow for misalignment between the pro-shaft and the gearbox. But in the case of an aquadrive, the use of two CV joints is to allow for lateral movement of the engine relative to the thrust bearing and therefore pro-shaft during operation. In that context, mounting the pulley and motor connection at this intermediate point feels potentially like a being a potentially risky half-way house.

I had in my mind that I should be committing to either mounting and aligning the pulley and motor with the prop-shaft and hull; or mounting the motor to the engine and aligning the pulley to the gearbox output shaft.

Mounting the shaft between the two CVs of aquadrive would presumably prevent mounting of the motor to the hull, as this would conflict with the intended lateral movement in that intermediate shaft. Likewise at attachment to the motor. I'd have thought this would be even more problematic if in either case a pillow block was used (if attached to the hull), as this would definitely impede the operation of the aquadrives.

I'm still unsure why attaching the pulley to the propshaft aft of the aquadrive isn't preferable - possibly with a pillow block to between the pulley block and the stern gland to ensure that lateral tension from the motor isn't transferred to the gland to an extent it is not meant to handle? From what I can envisage, the pro shaft aft of the thrust bearing is intended to be rigid with respect to lateral movement and therefore static relative to the hull. The only movement in this shaft should be rotational or to a limited extent along the axis of the shaft from propulsive propellor forces, both of which the pulley and motor can accommodate, as could a pillow block.

Of course - as you say - all of this implies that there is coordination between the operation of the motor and the engine. Clearly there are going to problems if the motor is in reverse while the engine is going forward etc! I think the Hybrid-Marine solution overcomes this at an electronic control level, which seems achievable at the motor controller side of things.

[valhalla360]

Originally Posted by alaskanviking

Boats are probably more similar to Locomotives (parrelel hybrid). however the electric motor would really lengthen things and need more room.

Maybe for 500ft+ superyachts, they are comparable.

The reason for diesel-electric locomotives is because a mechanical transmission is impractical when dealing with 10's of thousands of horsepower...especially when linking 5 locomotives together on a single train. The electric motors are acting as a transmission.

On your average 30hp sailboat diesel, there is no issue making a viable mechanical transmission.

[alaskanviking]

Originally Posted by johnwilde

Thanks alaskanviking,

So are you saying mount the pulley for the motor on the section of shaft between the two CV joints on the Aquadrive? I think mine is covered by some bellows, as shown in the photo, but that is a detail.

Essentially, yes. realistically its the only place in the system you could mount something. keep in mind that drive shafts and C/V joints are fairly easy to replace. you would have to get custom stuff made for you to go forward with this.

I would assume that typically a CV joint is to allow for misalignment between the pro-shaft and the gearbox. But in the case of an aquadrive, the use of two CV joints is to allow for lateral movement of the engine relative to the thrust bearing and therefore pro-shaft during operation. In that context, mounting the pulley and motor connection at this intermediate point feels potentially like a being a potentially risky half-way house.

wen i looked into the aquadrive i found it doesn't like much deviation of angle in the c/v joint. the manuals and white papers say it does, but when i read reviews and experiences the picture is much different. look like within a degree or to tops. maybe a little more if you use the rubber "Drive saver". its made to absorb the movement in the shaft angle that comes from the engine vibration, hull flex, and other such movement that changes the shaft angle slightly. the installation reports i read appears that it does this well provided you can get the shafts aligned within a few degrees.

so no you wouldn't want to add a pulley, belt or chain in this point unless you can add bearings that support theses side loads. same concept as adding an oversize alternator. it is possible to add such bearings however. at least one should be a two piece bearing so you can pull the shaft to replace the belt. best choice is probably a chain drive with idler so you can split the chain to replace. expect a lot more noise with this.


I had in my mind that I should be committing to either mounting and aligning the pulley and motor with the prop-shaft and hull; or mounting the motor to the engine and aligning the pulley to the gearbox output shaft.

are you talking about having the motor in line between the transmission and engine? I think this would be prefered but your talking much more engineering here and less diy. possible but more difficult. there are transmissions that are divorced in between shafts like that. walter v-drive comes to mind. i think they connect to a velvet drive via a shaft

Thinking on this if you found a motor with the shaft that goes out both ends, you could fabricate c/v joints or couplers to put on both ends and install it in the middle of the shaft length. it would take a lot of room so would depend on your motor and shaft length. possible
.

Mounting the shaft between the two CVs of aquadrive would presumably prevent mounting of the motor to the hull, as this would conflict with the intended lateral movement in that intermediate shaft. Likewise at attachment to the motor. I'd have thought this would be even more problematic if in either case a pillow block was used (if attached to the hull), as this would definitely impede the operation of the aquadrives.

Essentially, yes and no. depends on the lateral load. you could do it with pillow block bearings, but everything would have to be aligned well and your essentially removing the advantage of the c/v joints. i imagine a device that bolts to your engine bed stringers like the engine. some engine vibration mounts would assist with some of the movement/vibration but the bearings would have to likewise move wich feels counter intuitive.

I'm still unsure why attaching the pulley to the propshaft aft of the aquadrive isn't preferable - possibly with a pillow block to between the pulley block and the stern gland to ensure that lateral tension from the motor isn't transferred to the gland to an extent it is not meant to handle? From what I can envisage, the pro shaft aft of the thrust bearing is intended to be rigid with respect to lateral movement and therefore static relative to the hull. The only movement in this shaft should be rotational or to a limited extent along the axis of the shaft from propulsive propellor forces, both of which the pulley and motor can accommodate, as could a pillow block.

if i understand this correctly, putting the pully/gear before the thrust bearing puts the lateral force onto the aquadrive thrust bearing which wasnt designed for that side load. it is possible using a chain drive, added bearing may deal with the lateral force. i would feal nervous about this as if something went wrong it could damage the packing gland or dripless connection. that would make me really think hard on that option.

Of course - as you say - all of this implies that there is coordination between the operation of the motor and the engine. Clearly there are going to problems if the motor is in reverse while the engine is going forward etc! I think the Hybrid-Marine solution overcomes this at an electronic control level, which seems achievable at the motor controller side of things.

looked into the transfer case idea more. attached are pictures of a divorced NP205. heavy duty 4x4 stuff here. do you see the three shafts. the two shafts that appear to be aligned, 1 is from the transmission, the other is to the rear-end ie same as our prop. the 3rd shaft is parallel to but off roughly a foot. yu would attach the motor here either directly with a coupler or short shaft. it wouldn't take much to fabricate mounts for the transfer case and motor. they change the mounting positon of these by rotating the mounts. this is to move it out of the way to add clearance. not sure how much you can play with here without starving things of oil. but ive seen some pictures of extreme mounting positions. regardless it all works in our favour.

those are all c/v joints and the unit is all gears. would be simple and inexpensive to have custom shafts built. 4x4 crowd does it all the time. there is a conversion kit to change the shifters to double shifters and hydraulic or electric actuation. this would allow you to the two output shafts independently ie you could drive the motor from the engine without turning the prop, or you could drive the prop solely from the engine without driving the motor, or drive both.

if you use a velvet drive 1:1 you get your neutral to separate the engine from the driveshaft and motor. the transfer case is 1:1 in high and 2:1 in low which matches a lot of the transmission ratios used that i have seen. that ratio is changeable. 1:1 would allow you to spin the motor faster for power generation at lower rpm, not sure if that matches the torque requirements well though.

cost wise i see used ones on the east coast in the $200-$400 range. built up extreme 4x4 NP204's are $1000-$2000. there is a fully CNC machined aluminum transfer case called the "Atlas" that may be a good option as they would work to customize everything to fit and match your application, they're expensive though. fairly simple inside you can rebuild them your self. the more i look at it the more the transfer case idea seems the easiest option to diy hybridize a boat. far more heavy duty than most of us could fabricate on our own.

[alaskanviking]

Here is the non divorced version of the NP205 transfer case. the way it mounts to the transmission is similar to how it would mount to a marine transmission. you would probably have to fabricate an adapter plate and change the input shaft to match the transmission output, but the 4x4 scene does this all the time so very possible

what i don't know fully, is how well it will take it when driving the one output shaft with an electric motor. i suspect this will be ok since its all solid gears. you push and pull a vehicle in gear sometimes. just not sure how it would be in reality. would be fun to experiment with this.

the idea of the changeable high low gearing is also very enticing. if you set the ratios up correctly it could be very beneficial. thinking running it close to 1:1 or high gear to spin the motor faster when generating power from the engine or the spinning prop, low gear would be more of a normal configuration. maybe have the ratios set to match the low and high bands of your engine to load it correctly or when you need a little more oomph. ill have to play with some numbers to see if that plays out and worth the effort.

[alaskanviking]

here is some pictures of the Velvet drive. model 71 and 72 works in this application. I'm not sure if any other marine transmission works similarly. i have a hurth v-drive configuration on my boat and have been looking to swap to this velvet drive vdrive set up as its more robust.

the shorter one is the base 1:1 gearcase. Forward neutral and reverse. has an oil cooler and filter. there is a short stubby nosecone with the shaft coupler

the longer one painted in blue is the ratioed planetary gearcase nosecone. you can get different gear ratios. i don't remember them off hand as i need a simple 2:1

as an option to the planetary gear case nosecone is the v-drive nosecone. 12 degree shaft. also come in different gear ratios.

the various nose cones unbolt and can swap out. my spare perkins has the gearcase nosecone and ill later swap to the v-drive. velvet drives are fairly simple so your supposed to be able to rebuild them easily yourself. not my cup of tea. however looking at things it wouldn't take much to fabricate an adapter plate to connect to a transfer case. probably would have to have a custom input shaft made but that's not difficult.

again the more i think on this a velvet drive mated to a transfer case is probably the easiest diy way to build a hybrid drive. a lot of the component are aftermarket but easy to get. is there other transmissions or components that could work? possibly, i just know these ones currently.