VVTL-i
 

So I've been researching this all day trying to find an explanation, but all I can seem to find is the same generic "doesn't meet EURO IV" emissions.

What was the reason why VVTL-i didn't meet emissions? From everything I've read about variable lift, that technology is designed to improve engine efficiency (fuel consumption and emissions)...

I see that VTEC (currently i-VTEC?) is still being used... so what's the deal here? Toyota has considered increasing the displacement or turbocharging to increase power for the next gen FT86... why not revisit the VVTL-i technology? If Honda can still have VTEC, why can't Toyota make a VVTL-i that means EURO IV (or whatever) emissions standards?

Again, I just could not find answers to any of the questions I had through google researching, so I figured I'd ask you guys. I can only imagine how much more badass our stock naturally aspirated FA20's would have been if Toyota would have implemented VVTL-i with it, or would be if they implemented VVTL-i with a mid-cyle refresh.

tl;dr Why exactly did VVTL-i not meet emissions, and why is Honda still allowed to use i-VTEC while Toyota had to abandon VVTL-i?

Because, in a nutshell, the technology doesn't reduce tailpipe emissions? I think you already answered the question with your own reasoning.

It's just a marketing name. Honda still uses it because they can get it to meet current emissions standards. Toyota couldn't, so they came out with a different marketing name.

-alex

I didn't answer my own question. Why doesn't it reduce tailpipe emissions, but i-VTEC does? Aren't they essentially the same thing, and if there was a minor difference causing VTEC to be emissions friendly and VVTL-i to not be friendly, why wouldn't they just make a minor change to it rather than discontinue it?

Marketing...? I don't get what you mean. Toyota didn't change the name of it... they are using VVT-i now, which they had before, which does not include lift and duration (variable valve timing only). Honda is still able to have variable lift and duration in their engines (in addition to variable valve timing obviously), but Toyota only has variable valve timing now... why?

EDIT: Just to clarify, Toyota was using VVT-i before they came out with VVTL-i with the Celica engine (2ZZ-GE). VVTL-i is a more advanced engine technology that allows the engine to vary the cam lift and duration in addition to the valve timing, improving low end torque stability while improving high rpm peak power. In 2006, VVTL-i was unable to meet EURO IV emissions, and was abandoned by Toyota.

And doesn't koenigsegg own that technology as well...

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I thought the Koenigsegg technology was a camless technology with infinitely variable valve timing/lifts/durations/etc? Or maybe that was a different company that I am thinking off... I dunno, I'll look into it further.

Any time you increase valve lift, you increase emissions. It may be that Euro emissions testing changed to include the operating conditions where the high lift cam is engaged.

Whenever a manufacturer says they didn't do X because Y, you can generally assume that it's a cost issue, not that it's beyond their engineering capabilities. Honda has decided to continue using i-VTEC, but they've invested more time and money in that system. Every i-VTEC engine, whether designed for high performance or fuel economy, is very similar. The VVTL-i system was used in only 2 engines. Toyota decided it wasn't financially feasible to continue to develop that system.

You are correct.

Honestly.... why did Nissan discontinue their NeoVVL technology? You're making a simple question way too complicated.

Honda found a way to keep their i-VTEC system relevant and up to date with Euro IV (and later) standards. Keep in mind the K-series engine is still in production.

Toyota found no need to use this, and also have a lot more engines developed in the same period as Honda. Keep in mind that a lot of performance/efficiency targets can be achieved without resorting to expensive valvetrain/cyclinder head designs, making it easier for an engine to be serviced.

In reality, the answer you want is already said by you: it didn't meet Euro IV standards. That's all. It's the same with CAFE standards, if a manufacturer feels they can't meet the raised fuel economy standards, at some point they'll just choose to phase out certain cars/trucks to meet this goal.

That's all.

-alex

Thank you for the explanation. Makes sense.

Doesn't increasing engine displacement increase emissions too, though? With all other things similar, wouldn't a smaller engine with VVTL-i (2.0L for example) be capable of better emissions than a larger displacement engine with just VVT-i (2.5L for example)? This is the area where I'm not as knowledgable, hence why I'm asking.

Also, that is unfortunate that Toyota decided it wasn't worth the cost. I'm assuming that they decided that hybrid technology was a better use of money and time than following in Honda's footsteps.

(If you have a link to somewhere with this sort of info, could you please share it with us?)

I'm wondering when we'll see pneumatic valvetrains like used in F1.

Somewhere I read about an engine that used variable valve lift to eliminate the throttle body. I'm assuming the valves opened only very slightly for idle, and opened more as more power was needed. Neat idea IMO.

Also saw something using solenoids to actuate the valves electronically I think.

[ame="http://www.youtube.com/watch?v=qZ9k4Ohssu8"]BMW Valvetronic Variable Valve Lift - YouTube[/ame]


[ame="http://www.youtube.com/watch?v=N3fSfBQSK0w"]Cargine - YouTube[/ame]

Another reason that should be mentioned here is that this is primarily a subaru engine. So it's easier to use subaru technology like avcs, and avcs isn't able to control lift and duration, while avls can control lift and duration but not timing. My guess is that there isn't enough space to fit these two techonlogies under the hood given the boxer configuration.

these systems were all devised to EITHER increase lift/duration OR vary valve timing incrementally, if they implement both, the cost (and often the the strain on the oiling system) increase drastically, it is hard to do both with one technology,

Being able to adjust the valve timing as the FA20 does, allows them to improve both power and emissions, while also allowing them to remove any external systems related to EGR because the cams can be phazed to allow "internal" EGR

Honda relies much more heavily on their "VTEC" branding to sell cars than any other brand, which is why they have used the same moniker across several generations of motors even though the technologies aren't related much at all...

Cost vs benefit. They decided the extra complexity and expense was not worth the cost. Or would not be worth the cost given the price point they had targeted for the car. It's just simple economics.

I think you're on the money with this, if there is any upgrade with the current FA20 it'll be a lift version (assuming that's possible). I know the hybrid stuff seems to be there but Yamaha was the ones to do the lift in the celica, corolla and lotus (correct me on that last one) with the 2zz.

Now emissions and all that jazz not sure, but it seems like an avenue they will wander down, possibly already have and discarded not sure..

Good points, but I disagree with the following statement:

The i-VTEC in use on modern Honda engines works in the same way as the original VTEC, with regards to the mechanism of variable valve lift. The modern 2-rocker i-VTEC works in the same manner as the original VTEC-E introduced back in the 90's, and the modern 3-rocker i-VTEC works in the same manner as the original VTEC systems. The only difference is they switched from belt driven to chain driven cams in order to use oil pressure actuated variable cam timing sprockets, as Honda engineers apparently have an aversion to high pressure oil in close proximity to rubber belts.

To my knowledge, all i-VTEC engines use both VTC and VTEC systems.