Annoying Engine Regulations 2

[RodRico]

When I say my prototype is 50cc, I mean the volume of air moving into the cylinder is 50cc (49.5cc actually). Because I'm employing Low Temperature Combustion to prevent formation of NOx, however, my engine runs at now more than 0.48 equivalence (with 1.0 being stoichiometric). That means my effective displacement for comparison with other 50cc engines is 21.2 cc (meaning I'm putting in as much fuel as a 22.2 cc engine running at full stoichiometric). Why does this matter? Everyone regulates scooters to some cc figure (50cc being the lowest common figure) based on the amount of air they consume. As a result, I'm being penalized by the fact that I use Low Temperature Combustion to reduce emissions . Nonetheless, My analysis indicates an 11% improvement in torque, 76% reduction in fuel consumption, and 66% reduction in volume relative to the very popular GY6 engine (

http://fixmychinesescooter.com/139qmb-gy6-50cc/)

and even greater improvements relative to Honda's 50cc four-stroke (

http://engines.honda.com/models/model-detail/gxh50).

 

[BrianPetersen]

This is the least of your worries. My own opinion is that you'll learn about heat transfer and cylinder leakdown the hard way, to the extent that the engine simply won't start, in which case its legal classification won't matter much.

 

[RodRico]

Brian,

Are you having a bad day? You don’t usually troll.

Rod

 

[BrianPetersen]

Yes, sorry. Too many people not doing what they said they would ...

 

[SuperSalad]

What is the penalty your design is receiving?

Andrew H.

http://www.mototribology.com

 

[RodRico]

MotoLuber,

The intent of the 50cc limitation is to constrain deliverable power for safety reasons. Power is related to fuel load, not air volume, and an engine controller can intentionally limit peak fuel load (to limit maximum combustion pressure and temperature, for example). Thus, the intent of the regulation is not accurately expressed by the language, and it unnecessarily limits innovation. In this case, the innovation they're limiting is one tied directly to the emission of NOx, the most damaging greenhouse gas emitted by internal combustion. That doesn't seem very wise.

Rod

P.S. Before someone says "but an owner could reprogram the controller to deliver full fuel load," note my mechanical fuel injectors *can't* deliver more fuel than that required to develop 0.48 equivalence, and the engine's components and cooling system would be overstressed even if they could.

 

[CWB1]

Can you please cite or link to a regulation so we know what you're talking about?

Engine emissions are regulated based upon power output, not displacement. Not sure what safety regulation you're referring to that's based upon displacement, the only one remotely relevant I can think of is a few odd states' motorcycle licensing exemptions for scooters however I'm not sure how that's negatively impacting your design.

 

[BrianPetersen]

Mopeds have the engine displacement "cast in stone" in the vehicle classification rules. Each province/state has their own set of classification rules but "moped" or "motorized bicycle" is always 50cc limit. There are some additional requirements pertaining to maximum speed, etc.

In my province it's in here:

https://www.ontario.ca/laws/statute/90h08

and it's in the definitions:

“motor assisted bicycle” means a bicycle,
(a) that is fitted with pedals that are operable at all times to propel the bicycle,
(b) that weighs not more than fifty-five kilograms,
(c) that has no hand or foot operated clutch or gearbox driven by the motor and transferring power to the driven wheel,
(d) that has an attached motor driven by electricity or having a piston displacement of not more than fifty cubic centimetres, and
(e) that does not have sufficient power to enable the bicycle to attain a speed greater than 50 kilometres per hour on level ground within a distance of 2 kilometres from a standing start; (“cyclomoteur”)

 

[CWB1]

Interesting. Here stateside mopeds fall under the same legalities as scooters so there really isnt anything I'm aware of that limits them to 50cc, and some scooters are 600cc or more for highway use.

 

[wayne440]

The Commonwealth of Kentucky, USA has a Class E "moped license". Here a moped is defined as having: "No more than two (2) brake horsepower, a cylinder capacity not exceeding fifty (50) cubic centimeters, an automatic transmission not requiring clutching or shifting by the operator after the drive system is engaged, and capable of a maximum speed of not more than thirty (30) miles per hour." (reference KRS 189.285)

 

[RodRico]

Wayne,

The definition of a "moped" varies all over the US. The regulations you cite from Kentucky are also poorly written. Torque at 2,626 RPM (for example) is what defines speed and, assuming the wheel rotation speed is maintained by an appropriate reduction gear, an engine producing 2 HP at 5xRPM will produce 5xTorque at the wheel compared to the same 2 HP engine running at 1x RPM directly attached to the wheel. That's a 5:1 range of vehicle performance! My point is that pseudo-technical laws written by lawyers are meaningless except for the *real* objective of "not more than thirty (30) miles per hour" (though they should add "at sea level on a level road on a calm day" to avoid other technical dodges of their intent).

This is also a great example of why governments should not be banning diesel, by the way. Properly designed and operated diesels with appropriate emissions controls produce no more emissions than a gasoline engine. Rather than target a technology, they should focus their attention on the objective (emissions) and employ effective testing that can't be gamed to keep industry honest. Such tests affect literally $1.6 trillion in auto sales globally, and manufacturers will game them if possible to improve or maintain sales. Thinking they won't is like playing with scorpions then getting upset when one stings. All this legal action against manufacturers is political gamesmanship to cover the fact that their testing methods are flawed IMHO.

Rod

 

[SuperSalad]

Maybe I'm a little slow on the uptake, but I'm still not grasping how you're design is being penalized or what the penalty is.

As far as I can tell, your 50cc design is being compared to other 50cc engines but since your design produces power similar to a 22cc engine you feel the comparison is unfair. What you want is to be able to compare a larger displacement engine (about 100cc) of your design which would use a volume of fuel comparable to other 50cc engines. Is that right or am I just missing the mark completely?

Andrew H.

http://www.mototribology.com

 

[GregLocock]

Basically, despite the incomprehensible modelling of vehicle performance, RodRico has run into the main reason why 2 strokes took over the moped market (or indeed any capacity limited market such as the old 250cc limit in the UK for learner's bikes), designing a 50cc 4 stroke to give acceptable performance was beyond most manufacturers.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[RodRico]

Greg,

"Incomprehensible modelling of vehicle performance"?

One of the most popular scooter engines for home-builds is the 50cc four-stroke GY6 engine (

http://fixmychinesescooter.com/139qmb-gy6-50cc/)

made by any number of Chinese companies. It's basically an open-source design based on an old Honda engine, and it produces 3.1 HP at 7500 RPM with 2.3 lb-ft torque at 6500 RPM.

I have investigated the global scooter market, and I assure you 50cc four-stroke scooters are actually quite common. I expect them to expand their dominance as China, India, and Southeast Asia continue ramping up emissions requirements. Current manufacturers include Honda (

http://powersports.honda.com/2018/metropolitan.aspx),

Yamaha (

https://www.yamahamotorsports.com/scooter/models/zuma-50fx),

and Vespa (

http://www.vespa.com/us_EN/vespa-models/sprint/sprint-50.html).

Rod

 

[GregLocock]

Your maths is incomprehensible, and shows a misunderstanding of gearing.

"50cc four-stroke scooters are actually quite common" because 2 strokes have been outlawed in many jurisdictions.


Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[LionelHutz]

I find it hard to believe that 4-stroke scooters are the most common world wide. The reason I don' believe it is because the areas of the world with heavy scooter use also tend to also be the areas of the world without exhaust regulations.

Sure, everyone makes 4-stroke versions to sell in certain markets that require it, but it doesn't mean the 4-stroke engines dominate the global market.

 

[GregLocock]

There's banning and banning. India effectively banned them by saying they must meet the same emissions regs as 4 strokes. Dhaka in Bangladesh just banned them outright (not just for sale) in 2002, same in Beijing last year. Many countries are banning them from sale in the next couple of years as a result of the Paris malarkey. The Phillipines, Taiwan, Europe, Canadia, Australia, Indonesia, Thailand all popped up in google. So a good spread of first AND third world countries are banning them or have banned them or have introduced emissions regs that are too hard to meet with 2 stroke tech.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[SuperSalad]

It's roughly an 80:20 split between 4-stroke and 2-stroke in regard to all motorcycles. Obviously that includes many non-scooters, but scooters make up a huge proportion of the motorcycle market globally so that statistic should roughly bear some semblance to scooters.

Link
Link (Slide 37 has 2T sales stats)

The thing about 4-stroke scooters is that they aren't that much more expensive anymore. They are much easier/cheaper to operate because:
- Not having to buy/add premix
- They take a lot longer to run the engine into the ground than 2T without any rebuilds

Easy and cheap to replace and maintain makes it attractive to people who don't want to spend any time or resources on the things.

Andrew H.

http://www.mototribology.com

 

[gruntguru]

"The regulations you cite from Kentucky are also poorly written. Torque at 2,626 RPM (for example) is what defines speed and, assuming the wheel rotation speed is maintained by an appropriate reduction gear, an engine producing 2 HP at 5xRPM will produce 5xTorque at the wheel compared to the same 2 HP engine running at 1x RPM directly attached to the wheel."

Not if the second engine makes 2 hp at the lower rpm. It will also produce 5x torque.

Knowing engine torque without gearing/rpm is meaningless because it is POWER that defines the limits of a vehicle's top speed and acceleration. "Torque at 2,626 RPM" actually defines a power output.

je suis charlie

 

[SomptingGuy]

So you are targeting the almost infinite scooter market then, but have realised that your engine's physical displacement is the measure that the regulators will use. Take a look at the arguments over how to measure the displacement of a (Wankel) rotary engine for comparison with a conventional reciprocating (4-stroke) piston engine.

Steve