Do J.D. even market such small appliances, these days?
"Well, we knocked the bastard off!"
Ed Hilary on being 1st to top Mt Everest,
(& 1st to do a surface traverse across Antarctica,
in good Kiwi style - riding a Massey Ferguson farm
tractor - with a few extemporised mod's to hack the task).
Do J.D. even market such small appliances, these days?
Yes, 18 not 8 years ago!
It's a strange story I picked up in an online article (I can no longer find or I'd post a link). Basically, the EPA Phase 1 emission regs for small handheld engines mandated a 32% reduction in UBHC in 1997. Then, the EPA proposed an 80% reduction in Phase 1 emissions for Phase 2. The manufacturers and their representative bodies objected but John Deere were alone in encouraging the EPA to continue with Phase 2 - which it did - but with a slightly less onerous 70% reduction over Phase 1. John Deere promptly sold its small engine division to a Japanese company.
Another document (I found yesterday) detailing the implementation of Phase 2 refers (obliquely) to the above and lists the maximum (combined) output of UBHC + NOx for a 20 to 50cc engine as 50g/kWh (as its final stage).
According to the original document JD's insistence that Phase 2 be pursued caused a lot of resentment and expenditure for others and led to a rush to patent various stratified charge engines and, a 4T that employed 2T oil mixed in the fuel as its sole method of lubrication. Such engines (eg, Stihl 4mix) I suspect were confined to the USA market and I've yet to hear of one in the UK.
BTW, the market for small hand held engines is colossal. Some 27m annual sales in the USA.
Do J.D. even market such small appliances, these days?
Yes, 18 not 8 years ago!
It's a strange story I picked up in an online article (I can no longer find or I'd post a link). Basically, the EPA Phase 1 emission regs for small handheld engines mandated a 32% reduction in UBHC in 1997. Then, the EPA proposed an 80% reduction in Phase 1 emissions for Phase 2. The manufacturers and their representative bodies objected but John Deere were alone in encouraging the EPA to continue with Phase 2 - which it did - but with a slightly less onerous 70% reduction over Phase 1. John Deere promptly sold its small engine division to a Japanese company.
Another document (I found yesterday) detailing the implementation of Phase 2 refers (obliquely) to the above and lists the maximum (combined) output of UBHC + NOx for a 20 to 50cc engine as 50g/kWh (as its final stage).
According to the original document JD's insistence that Phase 2 be pursued caused a lot of resentment and expenditure for others and led to a rush to patent various stratified charge engines and, a 4T that employed 2T oil mixed in the fuel as its sole method of lubrication. Such engines (eg, Stihl 4mix) I suspect were confined to the USA market and I've yet to hear of one in the UK.
BTW, the market for small hand held engines is colossal. Some 27m annual sales in the USA.
Fascinating.
I heard it was a Chinese company ...about 15 - 20 years ago??
Fascinating.
I heard it was a Chinese company ...about 15 - 20 years ago??
You could be right - I'd need to check the article (but can't find it). IIRC, the company was named.
And, in the interests of clarity - I think the 27m pa was USA only but it wasn't entirely clear. Even if global, it's still a hell of a lot of small engines being churned out.
“Ok, back on 2T topic, Motocross Action magazine (as a matter of technical interest) recently dyno-tested a Euro-4 Husky ( KTM near-clone) TPI 250cc enduro bike & sawed-out a bit over 47 RWHP - even in its 'soft-tune' form..
A potential light-lithe, 2T 750 triple, emissions legal roadbike using that cylinder basic set-up would make a farce of the new Moto 2 Triumph 4T, as a showcase of G.P. racing progress..”
Here are the emissions regulations through the year:
Note that the emission limits have nothing to do with the power the engine provides, or with the capacity of the engine. It is the grams emitted per pollutant (CO, HC, NOx) per kilometer covered by the vehicle.
According what the DirtBikeRider magazine wrote:
“But new 2018 model will come with euro 4 and it will easy pass euro 4 with elections fuel injection and lower emissions. But there is new problem for KTM, in 2020 we will have new big problem called euro5. But we all hope KTM will find solution for this and make EXC and XC models legal for street.”
the KTM TPI barely passes the euro-4 standards.
Question:
If you put three cylinders of the KTM250EXC-TPI / 2018 (euro-4 compliant) side-by-side (sharing the same crankshaft) to form a 750cc engine of a motorcycle,
what is the possibility the resulting 750cc motorcycle to be euro-4 compliant?
Manolis, a larger capacity motorcycle engine in a roadbike is, in regular everday running, operating on a
fraction of the rpm of the 1/3 capacity enduro unit, due to power/gearing advantage.
If a hard-running small engine complies with Euro 4 regs, then the issue of the multiple cylinder engine
ought not to be insurmountable.
After all, a Euro 4 - 6.5 litre V12 car engine must be flowing a proportional quantity of gaseous emissions,
- in relation to a 1.8 litre 3 cyl..
"Well, we knocked the bastard off!"
Ed Hilary on being 1st to top Mt Everest,
(& 1st to do a surface traverse across Antarctica,
in good Kiwi style - riding a Massey Ferguson farm
tractor - with a few extemporised mod's to hack the task).
per km (at the mandated speed) the 750 will be geared to displace about 2.1 times the 250's displacement
so it must be operated at about 48% of the 250's VE
and will use more fuel doing the mandated journey and so make more pollution
per km (at the mandated speed) the 750 will be geared to displace about 2.1 times the 250's displacement
so it must be operated at about 48% of the 250's VE
and will use more fuel doing the mandated journey and so make more pollution
Not necessarily, since the 750 can be (will be, for emissions 'in town' tests) running on lower throttle settings, too..
The 750 chassis/rider weight also need not be 3 times as heavy - for over-riding inertia effects, either.
"Well, we knocked the bastard off!"
Ed Hilary on being 1st to top Mt Everest,
(& 1st to do a surface traverse across Antarctica,
in good Kiwi style - riding a Massey Ferguson farm
tractor - with a few extemporised mod's to hack the task).
If you put three cylinders of the KTM250EXC-TPI / 2018 (euro-4 compliant) side-by-side (sharing the same crankshaft) to form a 750cc engine of a motorcycle,
what is the possibility the resulting 750cc motorcycle to be euro-4 compliant?
Providing the weight of the completed motorcycle isn't excessive, and the test cycle doesn't push the rpm down so low as to 4-stroke, then should be an easier pass than for the single cylinder 250cc unit.
As alluded to elsewhere, the required delivery ratio (ultimately VE) will be lower in each cycle of the test reducing UBHC (the most problematic 2T emission species).
The test cycle could be different for a 750cc engine relative to a 250cc engine though - as it is for small engines.
Have you attempted comparing outputs measured in ppm, g/kWh, and g/km yet? Oh boy, does the fun begin then...
A 2-stroke like the TPi of KTM is hurting at partial loads because it cannot help running with a high quantity of residual gas in the cylinder.
At idling,
at the beginning of the compression,
the pressure in the cylinder of the 2-stroke is near atmospheric,
while the pressure in the cylinder of the 4-stroke is less than 1/5 of the atmospheric.
The quantity of residual gas in the 2-stroke at idling is five times more than in the 4-stroke.
With a small quantity of air-fuel mixture “lost” into a big quantity of residual gas, the combustion in the 2-stroke cannot be complete / clean.
Reasonably, the triple 750cc TPi, which will run at substantially lighter load than the single cylinder KTM250EXC TPi (which barely passes the euro-4 emissions regulations), cannot but being worse.
The direct injection 2-strokes (like the E-TEC of Rotax / Evinrude / Bombardier) can use stratified charge (direct injection towards the spark plug) to improve the partial load operation of the 2-stroke. However at the areas of the cylinder wherein the mixture gets too lean, the flame outas out and the combustion cannot be complete / clean.
A way better solution for the 2-strokes seems the lean burn with HCCI combustion, like, say, the PatBam HCCI.
The lean mixture is not a limitation, any longer.
The combustion is not progressive, any longer, but instantaneous, or too fast:
At partial loads or idling the cylinder fills with air (no pumping loss during the intake, no sub-pressure into the crankcase).
Mazda claims for their SkyActiv-X HCCI a 20% fuel consumption reduction as compared to their current high-tech SkyActiv-G engines, and 40% fuel consumption reduction as compared to their MZR engines:
If the SkyActiv-X SP-CCI / HCCI and the PatBam HCCI can improve one time the 4-stroke engines,
the PatBam HCCI can improve the 2-strokes several times because, besides the combustion, it also addresses the worst problem of the 2-strokes: the partial load operation (sub-pressure in the crankcase, resulting in high quantity of residual gas in the cylinder, resulting in incomplete combustion etc).
If Mazda is right about the 20% fuel consumption reduction with their lean burn HCCI, the guess is that for the 2-strokes (characterized by mechanical simplicity and lower friction losses) the improvement could be more than 40%.
