Toyota Turbo plans revealed at Tokyo
11-25-13, 01:31 PM
#46
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VVT-i varies the timing of only the intake valves, advancing or retarding the opening (and closing) of the valves to allow for efficient running of the engine from low RPM to high RPM.
Valvematic offers continuous variation of the valve timing (advancing and retarding open/close times) AND valve lift (changing how "high" the valve opens and for how long it is open). With Valvematic (like BMW's Valvetronic) the throttle valve is not needed, rather the valve lift changes with accelerator pedal position to vary the amount of air allowed into the cylinder. With the throttle valve gone, so is the problem of pumping losses at partial throttle valve openings.
Valvematic only works on the intake valves (and perhaps may not work with DI / D4S as has been speculated). I wonder if VVTI-iw works on both intake and exhaust valves, and DI? I wonder what the "w" stands for?
11-25-13, 03:38 PM
#47
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VVT-i varies the timing of only the intake valves, advancing or retarding the opening (and closing) of the valves to allow for efficient running of the engine from low RPM to high RPM.
Valvematic offers continuous variation of the valve timing (advancing and retarding open/close times) AND valve lift (changing how "high" the valve opens and for how long it is open). With Valvematic (like BMW's Valvetronic) the throttle valve is not needed, rather the valve lift changes with accelerator pedal position to vary the amount of air allowed into the cylinder. With the throttle valve gone, so is the problem of pumping losses at partial throttle valve openings.
Valvematic only works on the intake valves (and perhaps may not work with DI / D4S as has been speculated). I wonder if VVTI-iw works on both intake and exhaust valves, and DI? I wonder what the "w" stands for?
Valvematic offers continuous variation of the valve timing (advancing and retarding open/close times) AND valve lift (changing how "high" the valve opens and for how long it is open). With Valvematic (like BMW's Valvetronic) the throttle valve is not needed, rather the valve lift changes with accelerator pedal position to vary the amount of air allowed into the cylinder. With the throttle valve gone, so is the problem of pumping losses at partial throttle valve openings.
Valvematic only works on the intake valves (and perhaps may not work with DI / D4S as has been speculated). I wonder if VVTI-iw works on both intake and exhaust valves, and DI? I wonder what the "w" stands for?
So if I understand correctly Valavematic combines VVTI & VTEC in one
Nissans's video demonstrates VVEL (Valavematic) well
http://www.youtube.com/watch?v=6i1rBkP8dYs
11-25-13, 04:15 PM
#48
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I never got it why the pumping losses would be gone? The piston still has to work against low pressure during the intake stroke at partial throttle, even though it is created by restricted opening of valves instead of a restricted big throttle valve. Hence, there still will be pumping losses..
11-25-13, 04:29 PM
#49
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The vacuum is contained entirely within the cylinder, and at light throttle openings you're not dealing with a large restrictive plate in the way. And you're also not incurring frictional losses from opening all of the valves a ton. You're only opening them as much as you need to. My BMW N55 with Valvetronic coasts like crazy on the highway. Very little engine braking. Gets very good mileage on long trips also, easily 30+ mpg for a 300hp engine.
11-25-13, 08:26 PM
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perhaps they are not ready to release that info yet? or maybe its the same system but they wont call it valvematic? anyways, its interesting because VVTi is a simple system. what can they do to it to make it "new"? variable valve lift is the next logical step imo. if bmw can fit valvetronic and DI in their head, i am confident toyota can figure it out as well.
11-26-13, 01:25 AM
#51
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perhaps they are not ready to release that info yet? or maybe its the same system but they wont call it valvematic? anyways, its interesting because VVTi is a simple system. what can they do to it to make it "new"? variable valve lift is the next logical step imo. if bmw can fit valvetronic and DI in their head, i am confident toyota can figure it out as well.
In any case, it is not the battle of acronyms.
11-26-13, 06:51 AM
#52
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The vacuum is contained entirely within the cylinder, and at light throttle openings you're not dealing with a large restrictive plate in the way. And you're also not incurring frictional losses from opening all of the valves a ton. You're only opening them as much as you need to. My BMW N55 with Valvetronic coasts like crazy on the highway. Very little engine braking. Gets very good mileage on long trips also, easily 30+ mpg for a 300hp engine.
11-26-13, 07:23 AM
#53
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So I wonder how it will compare, at least in terms of construction compared to the Benz CLA45 AMG engine, which is also a 2.0L. Looks to be pretty tightly integrated, and seems to be routing cylinder pairs to a twin-scroll turbo also.
http://www.mbusa.com/mercedes/future...odel-CLA45_AMG
http://www.mercedes-amg.com/engineer...?section=20l4c
http://media.daimler.com/dcmedia/0-9...0-0-0-0-0.html
http://www.mbusa.com/mercedes/future...odel-CLA45_AMG
http://www.mercedes-amg.com/engineer...?section=20l4c
http://media.daimler.com/dcmedia/0-9...0-0-0-0-0.html
Twin-scroll turbocharger for spontaneous response
The spontaneous reactions to accelerator pedal movements and the excellent throttle response are down to a fast build-up of charge pressure and torque. Mercedes-AMG addresses the challenges concerning the response of small-displacement turbo engines by combining a twin-scroll turbocharger with maximum derestriction of the exhaust system and multiple injection. Unlike conventional systems, a twin-scroll turbocharger merges the exhaust gas ducts of cylinder pairs in the flow-optimised manifold. The advantages of the special twin-scroll manifold: exhaust gas back pressure, exhaust gas temperature and exhaust gas impulse ensure an optimum gas exchange. By the same token, the engine's tendency to knock and the residual gas in the cylinders are minimised.
The spontaneous reactions to accelerator pedal movements and the excellent throttle response are down to a fast build-up of charge pressure and torque. Mercedes-AMG addresses the challenges concerning the response of small-displacement turbo engines by combining a twin-scroll turbocharger with maximum derestriction of the exhaust system and multiple injection. Unlike conventional systems, a twin-scroll turbocharger merges the exhaust gas ducts of cylinder pairs in the flow-optimised manifold. The advantages of the special twin-scroll manifold: exhaust gas back pressure, exhaust gas temperature and exhaust gas impulse ensure an optimum gas exchange. By the same token, the engine's tendency to knock and the residual gas in the cylinders are minimised.
11-26-13, 07:32 AM
#54
Dual VVT-I is both intake & exhaust.
So if I understand correctly Valavematic combines VVTI & VTEC in one
Nissans's video demonstrates VVEL (Valavematic) well
http://www.youtube.com/watch?v=6i1rBkP8dYs
So if I understand correctly Valavematic combines VVTI & VTEC in one
Nissans's video demonstrates VVEL (Valavematic) well
http://www.youtube.com/watch?v=6i1rBkP8dYs
nice find
explains it in good detail.
11-26-13, 08:54 AM
#55
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that engine is conventional. nothing new in its design. it's tuned to make a lot of power but i fear for the reliability....
11-26-13, 10:00 AM
#56
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I'm not sure it's "nothing new". It has an exhaust manifold which looks to be directly integrated with the head with two ports from each side of the engine going directly to the twin-scrolls. Direct injection. Closed deck engine design (as the 2JZ was), which is noteworthy. Lots of attention to cooling and engine coatings also. Engine design goes far deeper than consumer visible technologies like Valvetronic/Valvematic, DI/D4S, and which types of turbochargers are being used.
11-26-13, 02:44 PM
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I'm not sure it's "nothing new". It has an exhaust manifold which looks to be directly integrated with the head with two ports from each side of the engine going directly to the twin-scrolls. Direct injection. Closed deck engine design (as the 2JZ was), which is noteworthy. Lots of attention to cooling and engine coatings also. Engine design goes far deeper than consumer visible technologies like Valvetronic/Valvematic, DI/D4S, and which types of turbochargers are being used.
Honda is notorious for their open-deck engines.
11-26-13, 09:44 PM
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i used to love the idea of turbo chargers.... then I bought one. Well its good for the manufacturers. The days of 200,000 mile Toyota's is gone, gonna have to buy a new car every 100,000 miles. 
Hold onto those late 90's early 2000's Japaneese vehicles, (MADE in Japan) they will be in demand for decades to come.
I refuse to buy a CVT transmission. I refuse to buy (another) small turbo engine. I refuse to buy a cheap plastically painted silver interior. I refuse to buy live rear axles. I refuse to buy drum brake cars. Cars that get rid of the double wishbone suspensions for struts ala Civic or Camry... I think I've just described what is becoming of the "everyman" car's of today, ie Camry, Accord... now start stop? What's next skip shift from 1'st to 8th gear and piping fake engine noise into the cabin! Cars are becoming so lame to drive from the Japanese.
I drive a lot of rental cars from work, from everyone, it seems they are just getting cheaper inside and out. This trend doesn't seem to be getting any better.
Electric cars from Tesla...instant torque, less mechanical parts to wear out seem like they can't get here fast enough. I don't see anything on the horizon except the Tesla Model S....
Hold onto those late 90's early 2000's Japaneese vehicles, (MADE in Japan) they will be in demand for decades to come.I refuse to buy a CVT transmission. I refuse to buy (another) small turbo engine. I refuse to buy a cheap plastically painted silver interior. I refuse to buy live rear axles. I refuse to buy drum brake cars. Cars that get rid of the double wishbone suspensions for struts ala Civic or Camry... I think I've just described what is becoming of the "everyman" car's of today, ie Camry, Accord... now start stop? What's next skip shift from 1'st to 8th gear and piping fake engine noise into the cabin! Cars are becoming so lame to drive from the Japanese.
I drive a lot of rental cars from work, from everyone, it seems they are just getting cheaper inside and out. This trend doesn't seem to be getting any better.
Electric cars from Tesla...instant torque, less mechanical parts to wear out seem like they can't get here fast enough. I don't see anything on the horizon except the Tesla Model S....
Last edited by toy4two; 11-26-13 at 10:02 PM.
11-26-13, 11:06 PM
#60
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they use technology differently... Audi never uses both port and direct injection at the same time, it is one or another... could be due to patent from toyota.