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).

 

[RodRico]

LionelHutz,

I never said 4-stroke scooters *dominated* the market, only that they are quite common and will *ultimately dominate. Emissions concerns around the world keep increasing, and that will demand uncommon 2-stroke performance. That being said, *my* engine is a two-stroke, and my analysis indicates it will be low emissions. My largest concern is oil between the rings slipping out the ports, but I think I have that problem licked (using a technique similar to Wärtsilä's).

gruntguru,

Oops! I see my mistake! It takes work to move an object, and torque is rotational work, so I prefer to think that it's in the lead, in in reality, torque, horsepower, and RPM are directly related (HP=Torque*RPM/5252, Torque=HP*5252/RPM, RPM=HP*5252/RPM). In my experience, when people talk about gears, they are most commonly referred to as torque multiplers (or dividers as the case may be). Not to say it's never been said, I've never heard anyone say gears multiply/divide horsepower. If one wants to drive a wheel at 5252 RPM with 2 ft-lb of torque, the engine must have 2 HP (2*5252/5252). If one wants to drive the same wheel at the same speed through a 2:1 reduction gear, the engine would require 1 ft-lb torque at 10,504 RPM, and that's also 2 HP (1*10504/5252). Both provide the same torque at the same RPM and thus the same HP at the wheel. I should have thought through my statements more carefully and tested them in my spreadsheets before speaking aloud (I've never been good at math off-the-cuff). You're right to have called me on it.

SometingGuy,

I don't think I'll actually be in the scooter or small motorcycle business any time soon. My actual target is aviation because power/weight is king, the EPA is slowly pushing emissions onto piston engines that have had none, and the selling price of the engines has a nice retail premium that supports low volume manufacturing. I looked into scooters because I've decided to prototype a small engine to save money, and I was thinking I may lend out to scooter companies for evaluation to see if they'd be willing to invest the funds and epertise required to ramp up production for reduce costs.

Rod

 

[LadaTrouble]

[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]

Premix ? The last bike I had with premix was a BSA Bantam, and I didn't premix, we could get 25:1 at the pump, or add oil and fuel to the tank and shake the bike. My current 2T 50cc scooter gets nearly 2000km to a litre of oil, not a lot more expensive than a 4T. My last 2T street legal dirt bike 10 years ago lasted 30,000km on a piston, a comparable 4T of the time with far less HP would be lucky to get half that distance for a far more expensive rebuild. The last of the 2 strokes were very good, they didn't disapear because they weren't reliable or didn't perform.

A 50cc 4T scooter is so gutless it's almost dangerous, and is in some situations. My 2T keeps up with traffic in my town, I sometimes have to slow down for the dawdling cars. It meets Euro 2, which doesn't mean much, but it does have a cat. And we can still buy a 2T scooter in my country.

 

[SuperSalad]

Premix ? The last bike I had with premix was a BSA Bantam, and I didn't premix, we could get 25:1 at the pump, or add oil and fuel to the tank and shake the bike.

In the very same sentence, you say you didn't premix and then continue describing how you would use premix.

The point I was trying to make is; 4-strokes are pretty much dummy-proof and maintenance free, which is very attractive to people who don't want to spare a single thought about their vehicle. That demographic is an extremely large portion of the global population of scooter/small bike riders in my experience.

I'm not referencing the portion of riders who are caring for their bikes and using decent oil rather than the cheapest available stuff. I'm talking about the person who buys a cheap bike, runs it with the minimum care taken to keep the wheels rolling, and when they do stop rolling, they replace it with the next cheapest one and so on.

Andrew H.

http://www.mototribology.com

 

[LadaTrouble]

No, I wasn't premixing, I was mixing fuel and oil in the motorcycle tank, and riding away. Premix refers to mixing fuel and oil in a container and then pouring into the bikes fuel tank...I do that with lawnmowers and chainsaws, and I've done it with off road motorcycles, but since the '70's most 2 stroke road going motorcycles have used an oil pump and tank. That makes a 2 stroke pretty much dummy proof and maintence free, far more maintenace free than a 4 stroke.

The 2 stroke hasn't been killed by any unreliability or performance issues, nor by rider preference, it's been killed only by government legislation.

 

[gruntguru]

Grrr - semantics.
Premix - the oil and fuel are mixed before induction into the engine.
Not premix - the oil is held in a separate tank on the vehicle and metered to the engine by a system integrated into the vehicle.

je suis charlie

 

[LionelHutz]

The whole argument is rather moot anyways. I highly doubt the design would ever make it into a scooter. Being a 2-stroke and too complex pretty much sink it.

 

[RodRico]

LionelHutz,

It’s a two-stroke supercharged HCCI engine with low emissions, high efficiency, and high power density (in theory). It doesn’t require oil injection or premix, and is about as complex as a four stroke. That being said, my primary target is aviation as it’s well suited to that market which will be the last market to be killed off by electrics.

Rod

 

[enginesrus]

Annoying Engine Regulations! In my opinion all agenda based, and I'll stop there.
Would the crying stop if hydrogen was the fuel used? Battery power, ignored are the impact of the manufacturing process of the battery's.