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Posted: 03:24 - 04 Apr 2019 Post subject: |
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Nope, just curious. I thought this was Bike Chat Forums not Bike Psychoanalysis Forums ____________________ Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter |
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Posted: 03:28 - 04 Apr 2019 Post subject: |
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Thanx, I've found a few articles like that "hey guys! we got the solution!" but only a cursory explanation of how it works. So far I've seen mentions of TPI which sorta looks similar to a typical 4-stroke carb to EFI "upgrade" i.e. throw away carb and replace with throttle body and a port fuel injector. Then there's the "electronically controlled carb" in Derbi's specs. Is that just a dumbed down label for TPI? ____________________ Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter |
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stevo as b4 World Chat Champion
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Posted: 09:33 - 04 Apr 2019 Post subject: |
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Awkward middle age man or as said another Tara?
What are you trying to do, design and engineer a new saviour to the two stroke engine? But an EFI two stroke to mess with in the shed? Convert your existing bike to EFI? There's always a reason why people want to know stuff, so there's no point in trying to be all cryptic and obstructive.
Electronic carbs, have one or more circuit that has a jet that is controlled by a solenoid operated valve. They usually are on the idle circuit or a power jet or both. And they are linked to an ECU that has control of the ignition map and any other features like exhaust valves or exhaust temperature control.
Such systems are as old as the early Suzuki RGV 250. Its nothing new, and by todays standards not that advanced in terms of the software and electronics used. It also is a slippery slope of covering simple two stroke engines in sensors and unnecessary electronic crap that isn't going to give them any more peak power, mechanical reliability, or huge gains in fuel consumption and particularly emissions.
EFI into a throttle body intake is basically a better version of a carb, in that with good ECU mapping and loads of sensors you can get more ideal fueling over a wider range of conditions and situations such as ambient temperature and altitude etc. Its very possible to fit this to two strokes, but it's again eating away at their light weight and simple benefits.
When you get to TPI and then extremely difficult DI systems, then you get lots more problems to solve and can make a two stroke worse in some aspects as well as ramping up the complexity so much it's diminishing returns.
You can't make a petrol fueled two stroke clean enough to be acceptable and have a serious future while they burn any oil at all. KTM know this better than you or I and are just padding into the tide for as long as they can before it becomes economically un-viable.
The thing to remember is that there's no reasonable life saving cure for the two stroke engine. Its dead technology and huge companies have spent millions trying to get away from this inevitable end, and realise it's not worth it, and more so that people won't race to accept and adopt them in today's climate.
You can design a two stroke engine that has a wet sump and needs to burn no oil to speak of in combustion. You can also scavenge them far better and more efficiently than using pressurised crankcases and fancy shaped big fat exhausts. But you have now built an engine more complicated and expensive to build than a four stroke engine you could have started with in the first place. See the logic in that?
Making four strokes more efficient or less polluting and more economical is extremely difficult now as it is, why would anyone want to shoot themselves in the head trying to do this with a two stroke? There's a reason why there are no direct fuel injection superbikes, and it's not all about weight and cost.
The limited time left for ICE engine development is in going back to early principles of going slow, purging spent gases more completely , and trying to not waste any energy as heat.
Fucks sake I've just turned into Teff. |
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bhinso World Chat Champion
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Easy-X Super Spammer
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Posted: 12:04 - 04 Apr 2019 Post subject: |
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stevo as b4 wrote: | ...Fucks sake I've just turned into Teff. |
LMAO!
There are a few videos on YouTube where similar model carb vs TPI comparisons are made but they're a bit light on detail. The general (maybe paid for) message is that there's very little performance difference but you do get better efficiency and emissions at the cost of extra electronics. For some reason I don't trust these videos - feels more promotional than informational.
But yes, I take your point on the convergence: add an ECU, TPI, fuel pump, oil pump, sensors, etc. and you have almost the same setup as an EFI 4-stroke...
However, 2-stroke isn't 4-stroke and while there's still some love for the beast it'll hopefully keep going... somehow. Feck! There's plenty of talk of bringing back emission-friendly rotary engines. Welcome back, Mazda RX (This time with a combo of both port and direct injection so I've heard.)
I'm not sure how I feel generally about this chase for low emissions. There's a certain elegant simplicity in, for example, a single cylinder carb fed engine especially 2-stroke. Certainly the "low carbon footprint" is a total sham IMHO but NOx is sadly a thing killing ppl right now Apologies for being such a tree-hugger.
There's a certain gloomy inevitability about it all but while having an ECU control a 2-stroke seems like blasphemy now it's rapidly become the norm on 4-stroke bikes and has been just the way it is on cars for ages.
As an aside I'm surprised manufacturers don't have OBD2 bluetooth built-in and their own branded variant of the Torque app. Maybe "app-connected" is way to attract the "youth" back to bikes? ____________________ Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter |
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Jmoan Brolly Dolly
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Old Thread Alert!
The last post was made 4 years, 360 days ago. Instead of replying here, would creating a new thread be more useful? |
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