Diesel Hydrostatic Drive

[Andi]

I have been contemplating a build for some time now, so far I either had no time or money or both. I'm about to get ready and have gathered lots of info and some material for the build. I've considered an all aluminum utility scooter or a small enclosed three wheeler using the YANMAR L100AE with a Comet CVT or preferably a hydrostatic drive (liquid CVT), but don't want it to be just a novelty.

The drive train has given me the most grief, the YANMAR aircooled engines (and clones) are very popular for many conversions due to their simplistic/functional design and power to weight/size ratio, but just as everyone else I would really like more hp. The YANMAR L100AE is comparable to a 150cc gas banger in power, from what I have seen and read about, which makes sense as its the same 9 hp for both.

At this point I'm favoring the three wheeler idea, it would also make the hydrostatic drive more possible due to the arrangement of required system components. I have a small enclosed all aluminum utility trailer I build many years ago and with little effort could easily convert to the drivers cabin to sort of a boxy BMW Isetta style.

I believe with proper component selection I should easily be able to attain 80% and over in system efficiency which I believe is higher then the CVT. I've put together a matching variable piston pump and vane wheel motor. I think I should be able to get about 80 km/h in top speed as the aluminum should keep the weight down and although boxy in design it will be an aerodynamic slopping front and low height.

I've even been thinking that at some point I could possibly add another YANMAR hydrostatic drive to increase the overall hp, a simple conversion of the wheel motor and the added flow will increase torque and top speed (flow = speed). While driving around town I could run a single engine and that at its sweet spot, then when required on highway stints simply fire up the second engine for extra speed. Sounds good too me in theory even considering the cost factor, as two of the L100 AE's are less then one 18 hp 3 cylinder water cooled YANMAR. Talk about back up ..... LOL

Any thoughts anyone? I know this is a Dieselbike forum, but technically a three wheeler has traditionally always been a modified motorcycle.

[Andi]

Thanks to the 37 interested viewers so far, any and all replies are welcome.

[Andi]

Help me out here people ...... throw me a bone please. What is the problem:

Too long ..... too boring ....... wrong topic ....... wrong build ...... wrong forum ...... or what?

Andi

[lex]

Have patience Andi,
The great minds of the furum are chewing over the many topics in your post!!!!!. If you search through the posts you will find discussions on hydrostatic drives and links to the 'hydrostatic hog' a harley based diesel hydraulic conversion. The topic has been covered a fair bit, so maybe folks don't want to cover the same ground. Most people on the forum have gone for CVT comet drives as this is a fairly simple set up. Some members have aslo gone down the diesel electric route. As I remember the main concern with hydraulic drives was that the wheel could be prone to locking up, but like I say other people discussed that rather a lot on the technical talk earlier on. There is a guy on the general chat section looking at an enclosed aero diesel electric with regenerative braking, have a look at that. The best way to get a response is to go to an existing topic, then start a new thread once the debate has got going!
I'm not experienced in any of the things you want to know about so all I can do is suggest that you look at some of the previous discussions first.
Cheers


Lex

[Andi]

Thanks lex, appreciate the reply. I did go through some of the threads and have read about the hydrostatic hog, infact I own the DVD he sells .... very interesting. Also read about the Diesel electric drive, also very interesting. I don't know so much about that, I know more about hydraulics as I work with hydraulic equipment and machinery. Repair/Service of course is one thing, design is whole other level.

Any reply and feedback would be welcome, not necessarily expecting an expert opinion, just some thoughts and shared experiences.

I would appreciate some feedback on the L100 YANMAR engine usage, what sort of experience anybody had so far and average performance.

Greetings form the Caribbean.

Andi

[Andi]

[roodesign]

did you see my posts on my soon to be enclosed three wheeler? there are some posts on this board, and also my blog www.roopod.com I went water cooled kubota and comet cvt but my chassis will be all aluminum...check it out
roo

[dieselbikin]

Hello Andi,
I’m not one of the great minds of the forum, but I can give you my opinion. First of all you must define what you are trying to accomplish. What will this vehicle be used for and what are your expectations concerning performance in terms of:

• Acceleration
• top speed
• economy
• Budgetary constraints
• Real transportation or entertaining experimentation
• Title, registration, insurance

Let the universal law of compromise be your guide through this process. If I were starting new project I would first broadly define my objectives for the vehicle. What are my top speed requirement is and how much horsepower would that take? What are my budget and fabrication skills? I would focus on simplicity, efficiency, weight, and aerodynamics. Vehicle weight will primarily effect acceleration, while aerodynamics will have a greater effect on top speed. The problems I would expect to run into is lightweight materials such as aluminum is expensive and requires special skills to work with while aerodynamic shapes are more difficult to build.

The Yanmar L100 clones seem reliable. 9HP should provide a conservative steady state cruise of 45+mph on flat ground barring high winds, while 18HP may provide closer to 65+mph. These figures are ROUGH estimates. Get other users' input on this. Before I go on I have to say I have a very limited knowledge of hydraulics. A hydraulic drive would be grand if you can afford quality positive displacement pumps; however, cheap gear pumps would not be as efficient. A hydraulic drive would give you great flexibility in motor and engine placement. I like the idea of two L-100s, but I rather than two pumps, could you simply use one”18HP” pump and integrate the second Yanmar via sprag clutch/centrifugal clutch on separate jackshaft for on demand power? If you could put a sprocket on Yanmar #1 crankshaft before the pump, then that sprocket would connect power from Yanmar #2 via chain/belt drive to sprag clutch. May be too much power transmitted through Yanmar #1 crankshaft?

. This same principle may work as well with a Comet CVT because a clutch tuned for 9HP with a particular final drive would not respond efficiently receiving and additional 9HP. However, a CVT tuned for 18HP may respond marginally well while receiving 9HP. My experience is that I must lose some low speed performance for topspeed and visa versa when tuning my clutch independent of final drive ratio. The same basic setup could be used with a CVT so that all power went through the same driver and driven. For maximum complexity you could have two complete engine/comet combos hooked to the same jackshaft. Driver #2’s belt would generate heat as it turned on the stationary driver#2 on stationary Yanmar #2 while driven #2 is spinning on the shared jackshaft. In this senario you could tune each clutch differently. Just a thought.

This is where an ATV transmission with hi/lo and reverse starts to make more sense. Also now that Comet is going out of business getting a surplus fwd/neu/rev gearbox may make sense. Also, lawnmover transmission with reverse can handle your type of power. Surplus center has some surplus hydrostatic transmissions for sale. Hope this helps.
Christopher

[dieselbikin]

Here is the 3 wheeler I would like to build. Simple design and self contained Beetle front suspension.