Serial Hybrid Cycle with ICE Generator Onboard

GX25 or GX35?
http://www.honda-engines.com/mini.htm
http://www.hondanews.com/categories/1061/releases/3128
http://www.rosz.com.pl/downloads/Power_Assist_Bike.pdf (page 6)

I have a mind to get one of these and start playing. I'm leaning towards the GX35 - it's only 1.2 pounds heavier but its low speed torque is much greater.

Any further thoughts?
 
Yeah, when i saw the pic of the trike, I figured that the 30 kph was not it's top speed, but it's efficient speed. Since a lot of us do all our riding at full throttle I usually state the capability of my bikes at that speed. When i built that e trike, efficiency had nothing to do with it. Its strictly a load hauler so I expect pretty lame performance.
 
Miles said:
GX25 or GX35?
http://www.honda-engines.com/mini.htm
http://www.hondanews.com/categories/1061/releases/3128
http://www.rosz.com.pl/downloads/Power_Assist_Bike.pdf (page 6)

I have a mind to get one of these and start playing. I'm leaning towards the GX35 - it's only 1.2 pounds heavier but its low speed torque is much greater.

Any further thoughts?
Click to expand...

Go for the 35. They don't make the GX-31 anymore. You need some extra oomph to overcome the losses in the generator. If you have more power than you need and run the engine at reduced throttle, it will last longer.
 
Raphael said:
when I'm telling what our bike uses @30kmh, that doesn't necessarily mean that's it's top-speed ;)
Top-speed w/o pedaling is 42kmh, and with light pedaling we get up to 52kmh. That's fast enough for me, and we can cruise along like this 2 hours and do 100km out of 1 battery pack with 576Wh. That's enough for us :)
Click to expand...

Raphael, your recumbent does seem more efficient than most reported here, if I'm not mistaken. Could you share some of the details with us. Perhaps, a description and some pics? I, for one, would like to learn from your experience.
BTW, 30kph=18.75mph which is above the UK legal limit, so not irrelevant to us.
 
Everybody who's ebike is legal raise thier hand. LOL.
 
I have been trying to figure out a hybrid engine /generator but I need 48 volts. A boat generator is as close as I have seen.

Has anyone anywhere done a small hybrid ??
 
48 volt golf cart charger seems to be the only soloution that you can go out a buy. they come in all kinds of amperages, I think 10 would be all you need. And a MUCH ligher generator than mine.
 
Check out this guys, http://www.staton-inc.com/Details.asp?ProductID=3318 Click on nuvinci kits and look for the hybrid electric drive motor. Could be 3/4 of what you are looking for once they get it on the market.
 
Now that is clever! And hes a-merican too! Makes my heart proud!
otherDoc
 
Here's the size of device I'm trying to focus on:
 
Miles said:
Have you had any contact with them, Paul? They look to be expensive..
Click to expand...
Just got the following reply:
"Paul:
Thanks for your follow up emails.
Yes, we did look at the thread. Coincidently, we received an email from another gentleman on a nearly identical subject, using different engines.
We are doing some preliminary work on an alternator in the 200-300 watt class made for engines in the 1.2 HP - 6 HP range. There may be enough of a market to allow us to mass produce these, which in turn would make the price reasonable.
We shall soon see. We will keep you posted. Thanks!
Jim Hudson
 
Interesting that pdf link, as it looks as if those small alternators are optimised for use on engines that are even bigger than the little baby Honda units we've previously mentioned (the spec sheet refers to 20cc to 80cc - an 80cc engine is pretty big).

Also, it looks as if Sullivan think that a much bigger engine will be needed to deliver a couple of hundred watts, as they refer to engines in the 1.2 to 6hp range (the small Honda GX series engines are around 1hp). This is puzzling, as I would have thought that it should be possible to get around 70 to 80% efficiency from a small genset, Assuming 70% efficiency, 200 watt power requirement and a desire to run the engine at it's best BMEP rpm for efficiency (typically around 2/3rds maximum power rpm), then:

Required electrical power output = 200 watts

Required mechanical power input = 286 watts (70% total conversion efficiency)

Required maximum engine power output = 429 watts = 0.58hp

This seems a bit lower than the engine power estimate given by Sullivan for some reason.

A small 4 stroke engine will typically deliver around 25 to 30 watts per cc when run at sensible (sub-8000rpm) speeds. This seems to indicate that the ideal 4 stroke engine for about 200 watts of usable output (429 watts maximum mechanical power output) might be one of around 14 to 17cc. There may well be some big model aero engines that approach this sort of size, but I have a feeling that the only ones that might be easily available at an affordable price are the small strimmer engines already discussed.

Jeremy
 
The engine depicted in the Sullivan pdf is a Desert Aircraft DA-50. Here is the website for that engine:
http://www.desertaircraft.com/engines_detail.php?Page=DA-50-R
you will see that:
Displacement: 3.05 ci (50 cc)
Output: 5.0 hp
Weight: 2.94 lbs (1.33 kilos)
Weight w/Standoffs: 3.13 lbs (1.42 kilos)
Bore: 1.6771 in (42.6 mm)
Stroke: 1.3779 in (35 mm)
Length: 6.7 in (170 mm)
The R maybe implies a slightly different model, but the weight is under 3lbs and the power is 5 hp!
So I don't see why such a big engine( :shock: ) is necessary for 200 watts! Think small!!
Not quite there yet are we Jeremy (but moving in the right direction, I think) :)
 
How about these 10cc petrol 4-stroke engines:
http://www.greenhobbymodel.com/saito.html
doesn't mention power output, but one of those mated to a Sullivan generator might do the trick?
 
and here's the specs. Maybe a 5cc engine would do?
http://saito-engines.info/specifications.html
 
Here's an interesting discussion:
http://www.rcgroups.com/forums/showthread.php?t=820447
... and another:
http://forums.makezine.com/comments.php?DiscussionID=2710
... and this isn't big enough but shows it can be done:
http://mysite.verizon.net/vze49gsg/
... 6.8cc giving 1.3 HP!
http://www.compagnucci.it/racing/uk/frame_uk.htm
 
Hello, I was looking for information on low powered ultra efficient vehicles (1000 km/litre as a minimum) and came across your discussions.
Many of you may find this of interest - it is a calculation to show the limits of motor-assisted bicycles at different speeds.
First off I calculated the power requirements for riding mountain bikes on flat ground at various speeds (based on Ken Roberts bike power calculator). I then calculated the additional power you need over your 80 watts personal input; then, using 24% motor efficiency, I calculated how long a litre of fuel would last; then calculated how many km I would travel in that time which gives km/litre; and then converted to miles/US gallon.
Code: 
Km/hr  Total   Power Over   Seconds       Km       Miles    Miles 
       Power    personal   travel by    /Litre      /hr     /Gal
     Required   80 watts   one litre                        (US)
16	    80	     0	         -	    -	   9.9	     -
17	    88	     8	   1006050	 4751	  10.6	 11174
18	    97	    17	    484692	 2423	  11.2	  5700
19	   107	    27	    311656	 1645	  11.8	  3869
20	   117	    37	    225592	 1253	  12.4	  2948
21	   128	    48	    174222	 1016	  13.0	  2390
22	   140	    60	    140194	  857	  13.7	  2015
23	   152	    72	    115918	  741	  14.3	  1742
24	   165	    85	     97882	  653	  14.9	  1535
25	   179	    99	     84033	  584	  15.5	  1373
26	   194	   114	     72997	  527	  16.2	  1240
27	   210	   130	     64108	  481	  16.8	  1131
28	   227	   147	     56750	  441	  17.4	  1038
29	   245	   165	     50609	  408	  18.0	   959
30	   264	   184	     45444	  379	  18.6	   891
31	   284	   204	     41024	  353	  19.3	   831
32	   305	   225	     37171	  330	  19.9	   777
33	   327	   247	     33827	  310	  20.5	   729
34	   350	   270	     30905	  292	  21.1	   687
35	   375	   295	     28328	  275	  21.7	   648
36	   401	   321	     26051	  261	  22.4	   613
37	   428	   348	     24023	  247	  23.0	   581
38	   456	   376	     22210	  234	  23.6	   551
39	   486	   406	     20585	  223	  24.2	   524
40	   517	   437	     19120	  212	  24.9	   500
41	   549	   469	     17797	  203	  25.5	   477
42	   583	   503	     16596	  194	  26.1	   455
43	   619	   539	     15505	  185	  26.7	   436
44	   656	   576	     14510	  177	  27.3	   417
45	   694	   614	     13600	  170	  28.0	   400
46	   734	   654	     12767	  163	  28.6	   384
47	   775	   695	     12013	  157	  29.2	   369
48	   819	   739	     11305	  151	  29.8	   355
49	   864	   784	     10653	  145	  30.4	   341
50	   911	   831	     10052	  140	  31.1	   328
51	   960	   880	      9496	  135	  31.7	   316
I have specific requirements for what I need so I will start another thread on it when I have written it up. I would appreciate any reviews and comments that any of you would care to offer, keep your eyes out for it.
Thanks
 
Paul,

Unfortunately, those Saito engines you linked to are like the vast majority of model aircraft engines, in that they are glow plug ignited and run on nitro, rather than petrol. Nitro does give more power from a small capacity engine, but is very expensive for use as a hybrid bike fuel. Saito do one petrol engine, as far as I know, the FG36. It's a 36cc four stroke, so it's near-identical to the Honda GX35, except that it delivers 3hp at (I presume) a higher rpm.

There are only a few petrol engines about in the model world, as far as I can see. Many of those I've dug out seem to have been based on converted strimmer engines, both two stroke and four stroke. Overall, I still think that a converted 4 stroke strimmer engine would be as small and light as anything you're likely to find in the model aircraft world, particularly after you've added the necessary intake and exhaust silencer, cooling fan etc that a model aircraft engine would need in order to operate effectively as a gen set.

Jeremy
 
For a small model engine, the O.S. FS30-S, I found this quote from this document http://ronney.usc.edu/AME514F06/Lecture4/PapacSmallEngineWSSCI-F03.pdf which seems rather authorative

RESULTS
The engine was tested with three fuels, each with 18% castor oil lubricant (manufacturer’s
specified minimum value). The maximum steady-state power achieved was 82.9 W, significantly less
than the O.S. Engines’ claimed maximum power of 0.5 brake horsepower (373 W). This is shown in
Figure 7. The maximum power and efficiency were obtained with fuel mixture B.
Click to expand...

I would hope that the small 4-stroke Honda and Makita motors aren't as as over-rated, would anyone have any idea?
 
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