ICE candidates for hybrid motorcycle

[liveforphysics]

Over here in Germany we have a small Wankel engine, that delivers up to 50hp@~10kRPM. It is designed for karts but has also been used as a range extender in a new Fiat 500e.
The weight and size is just the way you need it, but the prize not that much...

If you want to know more, I can dig a bit deeper...
Olaf

If your goal is having a fuel swishing oil/water heater, wank's are great.
If economy is any concern though.. the wankel is the king of fail.

 

[Jeremy Harris]

I don't know squat about the Prius engine, but it likely suffers from the same economy crippling problems all modern non-racecar engines are stuck with these days.

It's typically Japanese cleverness, with no real innovation. Because they fitted two big motor generators to the Prius, that are more than capable of picking up the peak torque requirements on their own (MG2 is something like 295lbs-ft near constant over its rpm range, the ICE is maybe 105lbs-ft max) they didn't need to make the ICE driveable in any way (it has no direct connection to the front wheels anyway, only via the diff arrangement and MG1, that Toyota call the 'power spilt device' in the HSD).

Once they'd freed up the ICE from the burden of having to run over a wide range of speeds, producing useful torque over as wide a range as possible, they were free to do all sorts of tricks to make it run as frugally as possible. It can run lean burn all the time, can run at just a handful of selected speeds where the variable valve timing, offset crank etc all contribute to its good SFC. They also got rid of all the accessory drives, to there are no belts at all. The steering is electric, as is the cooling pump and the aircon. There's no alternator, of course, so the parasitic loads on the engine are zilch, which all helps.

The Prius ICE wouldn't be able to drive a conventional car, it'd be like trying to drive with a generator motor that's tuned to only work over a narrow rpm range. The neat thing is that there really isn't any new technology in the thing - it's all existing knowledge that's just been integrated into a single, highly efficient, system. Systems integration, together with high build quality, seems to be what the Japanese auto industry excels at. The sad thing is that a very large number of the truly innovative technologies that they make work came from the West, but we seem unable to breach that 'valley of death' between an innovative idea and a production item.

Jeremy

 

[Jeremy Harris]

Over here in Germany we have a small Wankel engine, that delivers up to 50hp@~10kRPM. It is designed for karts but has also been used as a range extender in a new Fiat 500e.
The weight and size is just the way you need it, but the prize not that much...

If you want to know more, I can dig a bit deeper...
Olaf

If your goal is having a fuel swishing oil/water heater, wank's are great.
If economy is any concern though.. the wankel is the king of fail.

The little Aixro engine that Olaf is talking about is pretty darned good, especially when run over a narrow rpm range. It has an SFC that is comparable to a good piston engine, doesn't chuck out too much waste heat, is tiny and extremely light. I have extensively played with one as an aircraft engine, where it showed stacks of promise. The only real sticking point with it is noise, all attempts we made to quieten the thing down enough to be acceptable on an aircraft (we have a noise test requirement here for light aircraft) added too much weight.

Wankels have come a long way since the early RX engines, such that a friend who flies behind a converted Mazda Renesis engine gets better fuel economy than others flying conventional aero engines (which are already pretty good as a rule) and staggeringly good performance. The reliability has been excellent, too, the only problems he's suffered are exhaust failures (it seems that dealing with the high temperature, high velocity, exhaust flow on these engines is a common problem).

Jeremy

 

[liveforphysics]

Lots of clever tricks to improve things and remove burdens from the engine, but what cripples it's economy?

Why does a 1989 CRX HF have better fuel economy driving down the highway, when it's go zero fancy gadgets to help it along, and worse aero?

The modern engines (insight/prius/CRZ/etc) have every fancy dancy trick and advantage going for them, yet they burn more fuel to get you from point A to point B than 1980's cars with no tricks at all.

It's because they cripple the efficiency to please government standards (and to please a government that wants as much fuel burned as possible.)

 

[liveforphysics]

Over here in Germany we have a small Wankel engine, that delivers up to 50hp@~10kRPM. It is designed for karts but has also been used as a range extender in a new Fiat 500e.
The weight and size is just the way you need it, but the prize not that much...

If you want to know more, I can dig a bit deeper...
Olaf

If your goal is having a fuel swishing oil/water heater, wank's are great.
If economy is any concern though.. the wankel is the king of fail.

The little Aixro engine that Olaf is talking about is pretty darned good, especially when run over a narrow rpm range. It has an SFC that is comparable to a good piston engine, doesn't chuck out too much waste heat, is tiny and extremely light. I have extensively played with one as an aircraft engine, where it showed stacks of promise. The only real sticking point with it is noise, all attempts we made to quieten the thing down enough to be acceptable on an aircraft (we have a noise test requirement here for light aircraft) added too much weight.

Wankels have come a long way since the early RX engines, such that a friend who flies behind a converted Mazda Renesis engine gets better fuel economy than others flying conventional aero engines (which are already pretty good as a rule) and staggeringly good performance. The reliability has been excellent, too, the only problems he's suffered are exhaust failures (it seems that dealing with the high temperature, high velocity, exhaust flow on these engines is a common problem).

Jeremy

Ehh... I'm seeing the same stuff I've seen in every wankel.

It's ~294cc/chamber, meaning it's equal to a 588cc 4-stroke engine as far as the volume of air/fuel mixture that moves through it. It's making an embarassing 81.6hp/L for a performance engine that spins to 9k. Meaning it's putting that A/F mixture to use at the tune of about 55-65% of what an equalivant application sourced piston engine is able to do. Same wank specific output, same wank specific torque, same cripplingly huge combustion chamber surface area and end-gas pockets that have always been the ruin of wank efficiency. It does have a fantastic power to weight ratio though, much better than the RX series wanks.

I don't doubt that it's better than many aircraft piston engine offerings, but from the specs on lycomeing, continental etc, it's like calling it the tallest midget.

 

[Jeremy Harris]

Lots of clever tricks to improve things and remove burdens from the engine, but what cripples it's economy?

Why does a 1989 CRX HF have better fuel economy driving down the highway, when it's go zero fancy gadgets to help it along, and worse aero?

The modern engines (insight/prius/CRZ/etc) have every fancy dancy trick and advantage going for them, yet they burn more fuel to get you from point A to point B than 1980's cars with no tricks at all.

It's because they cripple the efficiency to please government standards (and to please a government that wants as much fuel burned as possible.)

Nothing, really cripples its economy, as far as I'm aware. I've owned two Prius' and they are pretty good, economy wise. It's a fairly big car (bigger than many realise) and yet easily gives over 60mpg without really trying. With a heavy right foot I can get mine to drop down to around 52 to 54mpg, but to be honest it's not really a boy racer type of car, so no fun to drive like that. If I drive the new one carefully, then I can get it up to over 70mpg fairly easily, without being extreme in terms of driving style (the old one (a 2005 model) would struggle to get better than maybe 64mpg and averaged around 54-55mpg).

Where it suffers is high-speed cruising, where the hybrid systems are all just unwanted peripheral junk, sapping power and not giving any benefit. One thing that takes a bit of getting used to is that it'll often return much better mpg in urban, stop-start driving than it will on a long run, pretty much the opposite of what we're used to. My old commute to work, around 40 miles each way on fairly slow (maybe 50mph max) roads and up and down lots of hills was ideal for my old Prius. It gave consistently better economy than anything else of the same size and weight on this run, barring the diesels (I used to frequently use hire cars on the same run, so had a chance to make comparisons).

Jeremy

 

[grindz145]

Over here in Germany we have a small Wankel engine, that delivers up to 50hp@~10kRPM. It is designed for karts but has also been used as a range extender in a new Fiat 500e.
The weight and size is just the way you need it, but the prize not that much...

If you want to know more, I can dig a bit deeper...
Olaf

If your goal is having a fuel swishing oil/water heater, wank's are great.
If economy is any concern though.. the wankel is the king of fail.

The little Aixro engine that Olaf is talking about is pretty darned good, especially when run over a narrow rpm range. It has an SFC that is comparable to a good piston engine, doesn't chuck out too much waste heat, is tiny and extremely light. I have extensively played with one as an aircraft engine, where it showed stacks of promise. The only real sticking point with it is noise, all attempts we made to quieten the thing down enough to be acceptable on an aircraft (we have a noise test requirement here for light aircraft) added too much weight.

Wankels have come a long way since the early RX engines, such that a friend who flies behind a converted Mazda Renesis engine gets better fuel economy than others flying conventional aero engines (which are already pretty good as a rule) and staggeringly good performance. The reliability has been excellent, too, the only problems he's suffered are exhaust failures (it seems that dealing with the high temperature, high velocity, exhaust flow on these engines is a common problem).

Jeremy

Ehh... I'm seeing the same stuff I've seen in every wankel.

It's ~294cc/chamber, meaning it's equal to a 588cc 4-stroke engine as far as the volume of air/fuel mixture that moves through it. It's making an embarassing 81.6hp/L for a performance engine that spins to 9k. Meaning it's putting that A/F mixture to use at the tune of about 55-65% of what an equalivant application sourced piston engine is able to do. Same wank specific output, same wank specific torque, same cripplingly huge combustion chamber surface area and end-gas pockets that have always been the ruin of wank efficiency. It does have a fantastic power to weight ratio though, much better than the RX series wanks.

I don't doubt that it's better than many aircraft piston engine offerings, but from the specs on lycomeing, continental etc, it's like calling it the tallest midget.

[/quote]

I really like the idea of this. I'm going to look into it, thanks Olaf! Unfortunately, it is a little big large, and Way wayy too expensive. To the tune of $5 grand...

So even though the power/displacement isn't the best, the power/mass (which matters) looks fantastic. The cool-factor alone would be nice... It does drag a bunch of extra weight along for the clutch too.

now all I can think about is Wankel engines...since these are used in go-carts alot, maybe I can look down the cart-engine path a little more..

 

[olaf-lampe]

If your goal is having a fuel swishing oil/water heater, wank's are great.
If economy is any concern though.. the wankel is the king of fail.

I don't know who started this economy discussion, but the original requirements were:

Here are my criteria:
~10-20hp output continuous duty (100-200cc)
~Preferably without motorcycle or other transmission, motor only
~High reliability (unfortunately no chinese junk)
~4 stroke (longevity/no gross 2 stroke smoke)
~water cooled (because a higher performance motor will probably have to be)
~fuel injected <---
~$400 or so

And AFAIK the wankel is thursty at acceleration but at steady RPM's its quite OK.
-Olaf

 

[Jeremy Harris]

And AFAIK the wankel is thursty at acceleration but at steady RPM's its quite OK.
-Olaf

My experience with Aixro unit was just that, at constant speed it was very fuel efficient, which is what made it attractive as an aircraft engine, along with its very light weight and small size.

The price is the killer for this application, though, as despite all its good points it's a pretty expensive engine.

Jeremy

 

[grindz145]

If you want to get a better estimate of the average power you need, and know the highway ICE fuel consumption for the performance of the sort of motorcycle you have in mind, then here's a quick and dirty way to 'reverse engineer' average power.

A normally aspirated four stroke ICE will probably have a specific fuel consumption (SFC) of around 300g/kWh (300 grams of fuel per kilowatt of power produced for one hour). A reasonable average speed for mixed use riding over a tankful of fuel will probably be around 40 to 50mph, maybe a bit less if you live in an urban area, a bit more if you ride on open highways all the time. Unleaded fuel has a density of around 0.72kg/litre.

For this worked example, let's assume that, for the sort of performance you have in mind, an equivalent ICE motorcycle uses an average of around 4 litres of fuel per 100km (around 62 miles per US gallon).

If the average speed over a tankful of fuel is 50mph (80kmh), then the motorcycle will have been using around 3.2 litres of fuel per hour on average ((80kmh / 100km) x 4 litres per 100km = 3.2 litres). This is about 2.3kg of fuel (3.2lt x 0.72kg/lt = 2.3kg). Based on 300g (0.3kg) of fuel needed to produce 1kw of power for an hour, it looks like the average power that this example motorcycle produced over the whole tankful of fuel was around 7.66kW, or 10.28hp (2300g / 300g = 7.66kW).

If you have regen, then based on the Prius data, you can expect to get a reduction in average power requirement of between 5% and 8%. This would reduce the ICE power needed in the example above from 10.28hp to maybe 9.5hp.

You can plug in numbers for other speeds and fuel consumption figures to the sums above to see how they vary. For an off-the-wall number at the high end of road motorcycle performance, a Yamaha R1 ridden at around 70mph average burns about 10 litres per 100km, which gives an average power used of around 26.7kW, or 36hp. This is a fair bit less than its claimed rated power of 134kW (180hp) and gives a ratio of maximum to average power of about the rule-of-thumb figure of 5:1.

Jeremy

I've ran numbers in a really similar way, and I use my ST1300 as my baseline metric. I'd like to have something akin to the performance of a R1200(gs) BMW motor. (lots of torque). I want to build something that's going to be interesting to someone who rides a bike like this on a daily basis like I do. I'm looking at about 36mpg on my ST as sad as that is so...20hp still seems pretty reasonable average. Ill run the numbers a bunch more. Right now I am leaning toward the GC160 just for testing, but when used continuous duty for "range extending" It might actually work out really well with 5kwh of lithium...

 

[grindz145]

If your goal is having a fuel swishing oil/water heater, wank's are great.
If economy is any concern though.. the wankel is the king of fail.

I don't know who started this economy discussion, but the original requirements were:

Here are my criteria:
~10-20hp output continuous duty (100-200cc)
~Preferably without motorcycle or other transmission, motor only
~High reliability (unfortunately no chinese junk)
~4 stroke (longevity/no gross 2 stroke smoke)
~water cooled (because a higher performance motor will probably have to be)
~fuel injected <---
~$400 or so

And AFAIK the wankel is thursty at acceleration but at steady RPM's its quite OK.
-Olaf

Fuel efficiency is definitely still a concern, but if I can makeup for overall efficiency by have a high power/weight motor, then I don't have to lug that weight around when in EV mode. Plus ...cool factor

 

[johnrobholmes]

yeah, maybe there. Just let me know if you want me to move it for you.

 

[grindz145]

Move it as you see fit John, I don't have a problem with it. Maybe we aught to have a hybrid section... There is that hybrid KLR thread and I'm sure theres a bunch others.

 

[Martin A]

I agree with Luke about rotary engines and efficiency, however on a small vehicle where the engine is likely to be little used fuel efficiency is not really a big issue. I would be interested in a Wankel generator for the benefits of size and smoothness although the noise would be a problem. No doubt greater minds than mine could come up with a solution to this though.

 

[Arlo1]

I agree with Luke about rotary engines and efficiency, however on a small vehicle where the engine is likely to be little used fuel efficiency is not really a big issue. I would be interested in a Wankel generator for the benefits of size and smoothness although the noise would be a problem. No doubt greater minds than mine could come up with a solution to this though.

The whole purpose of this is to have the highest total system efficiency so using a engine like that defeats the purpose.

 

[Hillhater]

Well , it seems you are going to have to modify your objectives a little, either less power, or more $$'s. :?
but if you truely want a light 4 stroke motor, then the kart race motors are probably your best bet (Aixro being an extreme example)
Look up Biland 250, Swiss Auto SA250, TKM 4T, Vampire, Oral, ...all of which are 200 -250cc 4 strokes with 25 -35 hp reliable output and weighing 10-15 kg with no transmission s attached (clutch maybe).
Unfortunately these are all $3-$4k new, but many can be found (especially the Biland) used , for much less

Start looking here for details.. http://www.engines4racing.com/

 

[grindz145]

Excellent hillhater thanks! Yeah, I had something used in mind so thats what justifies the cost. The Wenkel motor is trick though! But probably not worth the premium. I can get a Honda CRF-100-200cc motor (with transmission of course) in good condition for 200-300 bucks. Maybe I should look into gutting the transmission somehow. All in all I think the GC-190 will be a great test platform. Ill definitely look at these cart motors for the future, they're pretty much exactly what I had in mind.

Thanks!

 

[Hillhater]

... I would be interested in a Wankel generator for the benefits of size and smoothness although the noise would be a problem. No doubt greater minds than mine could come up with a solution to this though.

yep, the smart guys at Berkley built a small sized , wankel powered, gen'-set about 15 yrs ago ...
http://www.me.berkeley.edu/mrcl/mini.html

 

[grindz145]

Hah! Excellent! I just read yesterday, in the newest issue of cycleword, that Norton has built a series hybrid superbike that uses their own Wankel as the powerplant.

It's all been done

 

[gibbed]

In the case of my Insight, they went with a crank-offset, full needle bearing valvetrain, vtec, forged recip pieces to keep weight down as low as possible, super narrow main and rod bearings, lean-burn chamber design etc.
YET! Then they went and absolutely destroyed the engines ability to efficiently convert gasoline into shaft power when they decided to manifold the exhaust system in a way that doesn't require start-up enrichment to light the cat off. It's a freaking joke, all 3 exhaust ports connect into a single chamber in the head and outlet into the exhaust where cat actually bolts directly to the cylinder head. I'm not making this up, google a diagram, it's shameful. This results in a passive (and active) EGR design that no only creates massive pumping losses, but also results in a substantial amount of the fuel mixing with inert exhaust gasses and just getting steamed in the chamber (only taking away energy and contributing nothing), then the cat gets this steamed gasoline mixture and LOVES it. Loads of energy is spent thermally in that cat where loads of combustion occurs, and it ensures you get ultra clean exhaust with no HC's or NOx, yet of course the carbon emmisions are directly related to the impacted fuel economy, so it's a government rule pleasing setup that fails badly in respect to the big picture.

If you think that's backwards, you should see the EGR and aftertreatment systems that are being designed for diesel locomotives. The EGR systems have huge motor driven pumps and huge piping runs, and the after treatment systems use their own dedicated burner. The government rules are retarded because they are written by industry lobbyists instead of environmentalists.

 

[Arlo1]

In the case of my Insight, they went with a crank-offset, full needle bearing valvetrain, vtec, forged recip pieces to keep weight down as low as possible, super narrow main and rod bearings, lean-burn chamber design etc.
YET! Then they went and absolutely destroyed the engines ability to efficiently convert gasoline into shaft power when they decided to manifold the exhaust system in a way that doesn't require start-up enrichment to light the cat off. It's a freaking joke, all 3 exhaust ports connect into a single chamber in the head and outlet into the exhaust where cat actually bolts directly to the cylinder head. I'm not making this up, google a diagram, it's shameful. This results in a passive (and active) EGR design that no only creates massive pumping losses, but also results in a substantial amount of the fuel mixing with inert exhaust gasses and just getting steamed in the chamber (only taking away energy and contributing nothing), then the cat gets this steamed gasoline mixture and LOVES it. Loads of energy is spent thermally in that cat where loads of combustion occurs, and it ensures you get ultra clean exhaust with no HC's or NOx, yet of course the carbon emmisions are directly related to the impacted fuel economy, so it's a government rule pleasing setup that fails badly in respect to the big picture.

If you think that's backwards, you should see the EGR and aftertreatment systems that are being designed for diesel locomotives. The EGR systems have huge motor driven pumps and huge piping runs, and the after treatment systems use their own dedicated burner. The government rules are retarded because they are written by industry lobbyists instead of environmentalists.

Oh you meen like the diesel trucks that spray raw diesel into the exhaust pip before the cat to heat the cat because they says its better for emissions?

 

[grindz145]

It's better for emissions because its better for the oil industry...

 

[barntechsolar]

back in 2007 I set out to convert a motorcycle to electric. given the weight of agm batteries, I decided perhaps creating a Series Hybrid Electric conversion keeping the number of batteries to a minimum of 4 for 48 volts. the power plant has a 6.5 hp clone engine powering a 60 amp Chrysler alternator controlled by a custom built reg. charging voltage is 56 volts, amp max is 60. yes, the old style alternators will work at higher voltages. the motor is the brushed etek, controller is a curtis 1204 48 volt 225 amp. the frame is a 1987 LS 650 Suzuki Savage. this bike is BC registered and it had to be inspected. The insurance was based on the engine displacement which is 196cc

to date, this motorcycle is driven daily except for winter, and is been extremely reliable. it can be seen at this site, http://www.evalbum.com/2196

at present, I am working on another gen set for a electric conversion. Dead Batteries Are Not an Option. I have built around the old style big frame Ford alternator and a 13 hp clone engine.

 

[Arlo1]

back in 2007 I set out to convert a motorcycle to electric. given the weight of agm batteries, I decided perhaps creating a Series Hybrid Electric conversion keeping the number of batteries to a minimum of 4 for 48 volts. the power plant has a 6.5 hp clone engine powering a 60 amp Chrysler alternator controlled by a custom built reg. charging voltage is 56 volts, amp max is 60. yes, the old style alternators will work at higher voltages. the motor is the brushed etek, controller is a curtis 1204 48 volt 225 amp. the frame is a 1987 LS 650 Suzuki Savage. this bike is BC registered and it had to be inspected. The insurance was based on the engine displacement which is 196cc

to date, this motorcycle is driven daily except for winter, and is been extremely reliable. it can be seen at this site, http://www.evalbum.com/2196

at present, I am working on another gen set for a electric conversion. Dead Batteries Are Not an Option. I have built around the old style big frame Ford alternator and a 13 hp clone engine.

What part of BC are you in?

 

[Harold in CR]

Arlo, click the link to his evalbum build. Info is right there.