F150 with the 3.5L twin turbo eco boost

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Comments

  • wwestwwest Member Posts: 10,706
    As I said previously, if you throw in the REQUIREMENT for BOOST, heavy vehicle + towing, then the EcoBoost V6 will be more efficient than an equivalent HP/torque V8.

    But then we get back to that 2% figure...

    But for simply cruising along at a relatively constant speed the Ecoboost's FE suffers since it's now running, mostly, in detuned mode. 10:1 compression ratio when it could have been 12:1 or even as high as 14:1.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    Except you're still wrong about how it works. There is ALWAYS a requirement for boost, because there is ALWAYS load

    Look, if it went WOT for even a fraction of a second, the vehicle would lurch forward like any naturally aspirated vehicle going WOT would.

    If this engine had no turbos, and was just a 3.5L naturally aspirated V6 with a 10:1 compression ratio, it would still generate 260 lb-ft of torque at WOT. Which would be more than enough to cause an unintended surge in acceleration, before 'modulating.'.

    This. Does. Not. Happen.

    It works exactly the same as an NA engine. When some amount of torque is required, some throttle is applied. Boost is the automatic afterproduct of this same process in an FI engine.

    I.E. Everything you've said so far has been incorrect. There is boost available at partial throttle at highway speeds. It does not need to go WOT to spin turbines that are already spinning.

    There is boost available, and being used during highway driving. That is a
    fact.


    What part of being superior in terms of highway mpg to direct-injected NA engines with similar torques are you not understating?

    The main problem with your beliefs... Are the fact that EcoBoosts get good highway mpg. And you have been unable to quantify why this is. You are arguing with reality.

    Pay attention: I gave example of the EcoBoost 2.0 gets 15% better city and highway mileage than the DI V6 from GM in 7- seat SUVs.

    You are wrong, wwest.

    Pay attention: I gave example of EcoBoost 3.5 getting better city AND highway mpg than the DI V8 that Nissan Motors uses in a similarly sized vehicle.

    You are wrong, wwest.

    And you gave... Guesses and false statements :sick:

    It's not more efficient 2% of the time. It's more efficient ALL the time.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    Why do you think it is possible for a FI engine to uncouple itself from the transmission while in gear in order to spool the turbos?

    That really makes no sense at all.

    You realize that the engine has to move the pistons before turbos right?

    Which means if it went to WOT at highway speeds, it would feel the same or worse than if you suddenly stomped on an NA V6 with DI to WOT.

    That alone is enough to snap your head back.

    You're talking about going from about 60 lb-ft at highway speeds in order to overcome drag, to 200 or more. That doesn't happen under partial load there, buddy.

    Its an internal combustion engine... And same as any internal combustion engine, when you go WOT, you burn fuel and air and the pistons are forced to move to produce torque. This happens consistently across all engines. It is augmented by extra availability of air and fuel at low RPMs in an FI engine, but the core process is the same.

    It's not like these engines can do as you say, and just 'send throttle to the turbos' :sick: They don't pop out of gear to spool the turbos.

    Think about the goofiness of what you are suggesting. WOT in a 3.5 V6 is WOT in a 3.5 V6. Turbos or non, it's still the same transmission. The turbos are spooled post-combustion, not instead of. :confuse:
  • wwestwwest Member Posts: 10,706
    "They don't pop out of gear...."

    Oh, but yes, they do "pop out of gear".

    When you apply more/enough throttle for acceleration, incline, whatever, automatic transmissions will shift from lock-up mode, low torque cruising mode, to the use of the torque converter/multiplier. How long do you suppose, how many revolutions of the engine will it take the torque converter to "spool up" to the point of "solid'' coupling?

    You may also note that at the same time the engine RPM rises, that may, or may not, be due to a quick WOT and then back into a nominal position.
  • bigmclargehugebigmclargehuge Member Posts: 377
    What you are failing to realize is that drag is considered load to these engines. And FI engines deal with load by allowing boost that is generated proportional to every bit of fuel burned.

    Turbos are not clutched in. They are not on/off.

    Every bit of fuel burned causes a corresponding exhaust gas velocity, which causes a corresponding intake pressure available.

    This happens even at highway speeds, because drag is load. And there is a lot of drag on a pickup. It is not necessary to go WOT in order to get boost... That is available at partial throttle.

    If you needed full boost you'd need full throttle. If you needed 1/4 of full boost, you'd only need to go 1/4 throttle.

    Stop guessing.
  • wwestwwest Member Posts: 10,706
    I'm willing to bet that the EcoBoost V6 in the F150 has the wastegate open, FULLY open, whenever the lock-up clutch is engaged. I believe that the wastegate doesn't close unless the engine control ECU commands a "downshift"/out of lockup.

    How do you accelerate quickly from say, 20 MPH to 60 MPH.

    You press the gas pedal until you get to 60 MPH.

    So what's wrong with the EcoBoost engine ECU opening the throttle plate WOT until the desired boost level is reached in accordance with the position of the gas pedal..?
  • wwestwwest Member Posts: 10,706
    "Turbos are not clutched in. Thay are not on/off..."

    Wrong, dead wrong.

    The wastegate is used to "clutch" the turbo on/off.
  • dieselonedieselone Member Posts: 5,729
    I'm willing to bet that the EcoBoost V6 in the F150 has the wastegate open, FULLY open, whenever the lock-up clutch is engaged.

    Maybe at <1,500rpm, but during my test drive there was to much power available with the torque converter locked up for there not to be boost.

    I was driving a 55 mph or so running 1,500 rpm in the EB F150 I test drove. It would accelerate faster with the torque converter locked vs my 5.4 Expedition turning the same rpm. Granted it was easy to unlock the torque converter or get a down shift with enough throttle. But I didn't notice it being much different than the 5.4/6speed combo in my Expe (it's quick to unlock the converter and downshift too). The EB produces a lot more power at all rpm vs. ford's old 3v 5.4, the EB even felt like it had more off idle torque, the engine feels like it always has boost.

    With the transmission having a manual mode, I purposely locked in 6th gear and 40-50 mph, meaning the engine was kept under 2k rpm (even when the converter unlocked) and plenty of power was available without any perceptible delay in boost. IMO, no way does boost only happen with WOT, the engine produces power to smooth and linear for that to be the case.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    Hahahahhah!

    Go back to square one, genius! I now have figured out why you are so far off.

    Sorry, but you haven't a clue. The turbos are ALWAYS spinning. The waste gate is NOT used to 'clutch' the turbos totally off.

    At aggressive acceleration, WOT can be used, sure. But turbos are spinning at 1/4 boost at 1/4 throttle.

    But seriously it's an internal combustion engine. The fuel burns in
    the combustion chamber and then escapes THROUGH THE TURBOS, by spinning the turbine blades.

    The wastegate is actually used in the opposite fashion in which you are 'guessing' .

    The turbos spool up first, the wastegate is only called upon for excess backpressure in the turbo manifold.

    It's on wikipedia under wastegate. I suggest you look it up.

    No, you've literally gotten EVERY SINGLE POINT WRONG, wwest. Come back when you have attained knowledge.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    Let's begin by describing what a turbo wastegate is. A wastegate is essentially a device that bypasses some exhaust flow around the turbine section of a turbocharger to control maximum boost. A wastegate is usually controlled by a pressure actuator that is connected to manifold pressure. The wastegate is normally closed, held shut by a spring inside the actuator canister. When preset pressure limits are exceeded, the actuator progressively opens the wastegate, allowing exhaust flow to bypass the turbine, thus regulating manifold boost pressure.

    You see, the problem is... Your understanding of turbochargers is completely backwards.

    When you say it is normally open, it is actually normally closed, for quick spool of the turbos.

    When you say the turbos are not spinning at low throttle levels, they actually are.

    And no, the transmission does not decouple when mild boost is applied. You can be in 6th gear at 60 mph, and going uphill, the vehicle may not downshift, the RPMs may not raise, and it still goes to boost.

    Why? Because the turbos are always spinning, and boost is the automatic byproduct of even slight load on the engine (like slow acceleration or a slight hill) And even a slight incline is load.

    Same gear, same RPMs, and the engine adds boost and fuel to maintain velocity.

    FI DI engines can boost at low throttle and rpm settings. They downshift LESS than NA engines because they do not rely on RPMs as much for vacuum. They are more efficient in the real world as a result.

    Still waiting for you to quantify ANY of your claims. Lol.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    According to wwest:

    "Turbos are not clutched in. Thay are not on/off..."
     
    Wrong, dead wrong.
     
    The wastegate is used to "clutch" the turbo on/off.


    This is the poorest understanding that a self-proclaimed ' expert ' online could have ever demonstrated, and I'm not sure whether to laugh or shake my head. Probably one then the other.

    Dieselone, what wwest is saying is not possible under 1000 engine RPMs. The wastegate is like a blow off valve for the exhaust housing so that the exhaust blades don't shatter by spinning past 20,000 turbine RPMs.

    It is not a clutch to engage the turbos. The turbos are 'engaged' simply by exhaust gasses escaping the cylinders. They spin from start-up to just after shut-down, proportional to the amount of fuel being burned (except up top where the wastegate opens to slow the turbos down a bit). Wanna know why the torque peaks at 420 from 2200 RPMs on up to 4500? Because the wastegate opens at 420, to protect the small turbos from too much pressure.
  • wwestwwest Member Posts: 10,706
    If it pleases you to believe boost is beneficial with the throttle partially closed, BLOCKING the effects of boost, then that's okay by me.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    It's not about belief, it's about FACT.

    Did you look up the definition of wastegate? Have you read any of the Q&As with mechanics and engineers that PROVE that turbos are ALWAYS spinning? That they are NOT on/off?

    Are you able to qualify any of your statements with real-world data, or are you going to continue wasting up everyone's time and creating bogus posts?


    It's a pressurized system. Pressurized gases (air) can pass through partial openings. The amount allowed and demanded is proportional to the load and torque requirements.

    Partial torque requirements, partial throttle application, partial boost pressurizing through the throttle plate. Only what is needed.

    And the torque requirements are not always such to require WOT, but still some boost. It does not negate the positive affects.

    By your logic, a Naturally Aspirated engine would always go to WOT to gain vacuum, because why would you want to cut off vacuum? You should want all the vacuum you can get all the time, right? WRONG! You need a method of tempering air with fuel.

    It works the same in an FI engine. Partial load yields partial torque, and the amount of air required comes through the intake through the throttle.

    It just so happens that in a boosted engine, there is more air available at all times due to the fact that the turbos are always spinning relative to whatever current fuel burn is being used . The boost matches the amount of fuel being burned in steady-state driving.

    That is why the EcoBoost with 10:1 FI DI is more efficient than the GM NA DI. It has more air than it needs at all levels of load. The boost is ALWAYS playing a part in the combustion process.

    But if you keep adding air, you run lean. This is COMPOUNDED in FI engines, which is why they are not only equipped with throttle plates that restrict excess boost, they also come with blow-off valves and waste gates.

    Boost is actually very easy to acquire, since it is NOT clutched in, it is being produced proportional to fuel burned at all RPMs. In many situations the boost is more than what the engine is prepared to supply fuel for, and YES, IT DOES SEND EXCESS BOOST TO BLOW-OFF. NOT ALL BOOST GOES IN ALL THE TIME, THAT CAN CREATE OVERBOOST SITUATIONS.

    1) the turbos are ALWAYS SPINNING. They do not turn off until the engine stops burning fuel (i.e. shut down).

    2) the definition of a wastegate is the opposite of what you claimed. They are normally shut, unless the turbos are in danger of over-spinning (which happens over 420lb-ft worth of torque). That is the ONLY time a wastegate is typically open. (closed 98% of the time, open 2% or less).

    3) There is ALWAYS some pressurization at the throttle, open or closed (refer back to point #1). From 0.0001psi to ~13 or so psi, and everything in-between. The engine uses what it needs. It is not on/off. It is not all or nothing. They go to boost up to a dozens of times per highway mile.

    4) you said yourself, it is more efficient under boost. Well guess what? You were confused about how wastegates are used and that turbos are NOT clutched in. Now you should be seeing that using some pressurization (and pressure CAN pass through partially closed throttles), at ALL TIMES under load is why the EcoBoost is BEST IN ITS CLASS IN TERMS OF HIGHWAY EFFICIENCY.

    4) not all turbocharged engines are torque-converter automatics, genius. My point stands: they do NOT go to WOT as the only means of obtaining boost. If they did, they would cause ridiculous wear and uncomfortable driving, because some transmissions cannot be un-coupled unless manually. AND THE ECOBOOST IS NO DIFFERENT. IT WOULD BE INTERCHANGEABLE WITH ANY OTHER TRANSMISSION TYPE.

    Boost is stratified, and continuous at all load levels and rpms in an FI engine.

    If it pleases you to stay ignorant, then that is okay by me.
  • wwestwwest Member Posts: 10,706
    I'll stay ignorant.

    There simply is not sufficient waste ENERGY at partial throttle, certainly not cruise level throttle, to spin the turbine fast enough to generate any significant, useful, level of boost from a centrifugal compressor wheel.

    And why "ask" the turbocharger to generate intercooled compressed airflow just to be met downstream with the flow restriction of the throttle plate. Seems to me that might be asking for an early turbine failure from to overheating due to the restricting load on the compressor wheel.

    Oh, the Wiki dialog is pertinent only to the race venue where WOT is the 98% rule.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    I'll stay ignorant.

    Yes, that's obvious.

    This 'waste energy' is not excess energy. It is the SAME energy that moved the pistons. IT TAKES NO MORE FUEL TO SPIN A TURBO AFTER MOVING THE PISTONS THAN IT DOES TO MOVE THE PISTONS BY THEMSELVES.

    Now you need to do some research just on the principles of an internal combustion engine. Recently exploded gases are being forced out by the piston up-stroke. Anything downstream of that is going to be subject to high-speed gases and pressure. This is proportional to how much fuel and air were burned at combustion. They are very eager to escape. The engine must expel these gases. If you choose to call this 'waste energy' than so be it, but it is enough to spin a turbo at any amount of fuel burn proportional to that amount of burnt fuel.

    Seems to me that might be asking for an early turbine failure from to overheating due to the restricting load on the compressor wheel.

    Yeah, 'seems to you.' But that's not surprising. That's why there are blow-off valves in the intake stream. The compressor wheel just creates as much intake pressure as is proportional to the exhaust gases for any amount of fuel burned. The throttle plate and blow-off valve regulate how much make it into the combustion chamber.

    The compressor wheel never 'knows' what is happening downstream of it. As far as it knows, it is just being 'told' to spin because there are exhaust gases coming out the other side.

    This is not optional for the turbo. Wastegate is closed 98% of the time, gases are passing through the turbo 100% of the time, the exhaust wheel is spinning 100% of the time, as is the intake wheel.

    Why is it hard for you to understand that on the highway (say 10% of throttle applied) that 10% of total boost is correspondingly available? If 10% of total fuel were being burned, guess what? The turbos have no choice but to spin accordingly.

    You're just plain thinking of it wrong. You somehow think of exhaust flow as a parallel system, and it is not. It is a series system.

    You're thinking of it as a hydro-electric turbine can't be turned because there is another hydro-electric turbine above it, even though the flow due to gravity will still spool the second turbine after the first.

    Same here. The gas that moves the pistons IS the gas that spins the turbos. Why do you not think that escaping gases in the exhaust stream create pressure at the turbo exhaust housing? There is ALWAYS pressure. Therefore, always intake pressure as well.

    Which makes me wonder why you think this would cause failure of the compressor? They are designed to take 1000+ -degree heat since they are mounted to the exhaust housing, which is IN THE EXHAUST STREAM.

    That's what the intercooler is for. The compressor is designed to get hotter than the muffler. The air coming out of it will be at very high temp and needs to be cooled.

    Boost seriously happens dozens of times per mile. Every light tap of the accelerator generates light boost. Every single one.

    Did you know that semi trucks are under boost cruising on a straight, flat, level road due to the massive wind resistance and load of a 40-ton trailer?

    Well this is a smaller version of that, despite running on petrol. It's not very aerodynamic, and it weighs the better part of 3 tons.

    Also, ignorant one, THERE IS NO ALTERNATE MEANS OF GAINING AIR IN THE FI SYSTEM.

    All intake air is coming through the compressor and intercooler. That is a long road to travel using only vacuum.... which is why an FI system like the EcoBoost goes from 0.00001 psi to 13 or so psi, the system is ALWAYS PRESSURIZED to some degree.

    It is not on/off. It is proportional. There is proportional boost at highway speeds to the amount of fuel being burned at highway speeds (not a lot of fuel to be burned means a very small amount of boost is needed/generated).

    Why do you not understand that air moving in a series system can both move the piston and spool a turbo on its way out? These are lighweight high-temp metal wheels, weighing only ounces, creating almost no backpressure at all. And as the exhaust gases pass through them, they rotate the intake wheel at an equally high speed.

    They are used to pressure changing quickly and rapid velocity changes (i.e. spool).

    There is little danger of compressor failure by spooling turbos all the time at light load. Compressor failure is typical of heavy loads, which is the true purpose of the wastegate.

    The quote I gave about what a wastegate is is from Banks Engineering. Do you know who they are? They are one of the most respected makers of wastegates, turbos and FI systems for gas and diesel applications.

    If you don't like Wiki, then are you going to qualify your statements with ANY RESPECTABLE QUOTES? No? That's because it's your 'guesswork' based on a false understanding of these systems.

    Oh, the Wiki dialog is pertinent only to the race venue where WOT is the 98% rule.

    And you came to this conclusion how? Good grief, you are in ignorant denial.

    Any respectable reference will tell you turbos are ALWAYS SPINNING. Any reference will tell you that wastegates are CLOSED 98% of the time.
    I'll seriously take you for a ride with a boost gauge attached. It boosts on the highway while getting 23 mpg.

    All of your assumptions are wrong, and yet your only defense is "I refuse to read or qualify my statements" because it might undermine your flawed thinking? :confuse:
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    Exhaust pressure in a 2" line is equivalent to the pressure caused by the amount of intake air in a 2" line + the pressure caused by n mols of combusted gases.

    Which means exhaust flow is always more than intake flow. Natural expansion of combustion guarantees there is always more 'waste' pressure spinning a turbo than is required at the intake for any given throttle application.

    You do not 'ask' a turbo to produce boost. It does do naturally as a result of combustion, since it is in the exhaust stream. Always spinning.

    That's why FI engines are more responsive and efficient. They always have excess air going to blow-off, which required ZERO 'waste energy' to create. Open the throttle slightly and pressurized air enters freely.

    You said you were 'willing to bet' on these things? How much? $1? $1000? Because I'm all in, if you want to try to talk to a Ford Engineer about how their wastegates operate, etc. I guarantee you will lose that bet.
  • wwestwwest Member Posts: 10,706
    edited October 2011
    You need to learn why Atkinson cycle engines are substantially more efficient FE wise than their Otto cycle brotheren.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    You need to learn what a wastegate is, a blowoff valve is, and how FI is used.


    You also need to learn how not to contradict your own theories
    .

    You said yourself that the biggest efficiency gains are under boost. LWell considering tge turbos are spinning at all times it should have occurred to you by now how this engine is THE MOST EFFICIENT in it's torque class.

    compression ignition just benefits are compounded by their ability to run leaner.


    In either case, the turbos spin 100% of the time. It is powered by the gases escaping the exhaust valves on the up-stroke.

    Everything you have posted wwest has been based on false premise.

    Still waiting for you to qualify any statement you've made by reputable source.
  • wwestwwest Member Posts: 10,706
    edited October 2011
    You can go to motorcraftservice.com and for ~$12 you can peruse the method the EcoBoost PCM (Powertrain Control Module) uses to control the turbocharger "on/off" status.

    Hint: For a multiplicity of reasons the throttle plate position is uncoupled from the gas pedal position, "non-coupling" is the actual term used.

    Hint: PWM (Pulse Width Modulated) wastegate regulating solenoid valve.

    Hint: Under control of the regulating solenoid valve the wastegate bypasses exhaust pressure around the turbine unless/until the PCM computes that boost pressure is needed to meet the driver's expectation of ....TORQUE.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    Nobody is going to believe that because you name another automotive component that you are correctly describing it, High School.

    We already know you have no idea how or why a turbo or a wastegate is used. So now you identify that a vehicle carries electronics... That's super job for you.

    But, Hint: you still made up what they do, and even though every definition you found says turbos always spin while a turbod car is running, and that wastegates are closed 98% of the time, you made-up that that was only in racing... Even though that was never implied.

    Don't make stuff up that isn't there. Stop thinking you are smart, because you're starting to sound crazy with the cover-ups for the plain-English proof that you are wrong.

    Pulse Width Modulation is a term you took from intro toElectronics class. It is how electronics send signals. No-where does it say that keeps the wastegate open. You get a F for trying to sound smart using a term to say more than what you found.

    You are inventing processes in your mind that don't exist in real life.

    No-where does anything say turbo 'on-off'. You found a part called Powertrain Contril Module. Good for you. Nowhere does any diagram or description say
    that the turbo can be switched off.

    I never said throttle plates were coupled directly to pedal. But you're still wrong that they go WOT (based on air quantity) to spool the turbos, unless full torque is required.


    Hint:
    You aren't quoting any real language cited by any source, you are just piecing parts together and guessing that they work to support your false claims.


    What you are suggesting is not possible. The intake routing goes 100% through the compressor housing of the turbo.

    Even if your fabricated assumption that turbos turn 'off' was true, the compressor wheel would be spun by the intake vacuum.


    Which begs the question... Why are you not able to see that the turbo is an object that spins regardless.

    Stop lying and making stuff up. Don't just point out a part somewhere and give 'hints' as to what you think it does.

    ALL the literature will tell you that turbos are mounted in the intake and exhaust stream, always spin, and the wastegate is only for over-spool situations. There is no benefit to preventing gases through the turbine. None.

    Take the downpipe off any turbo and turn on the car. Video-tape the turbine
    wheel spinning freely in the exhaust stream at idle, wastegate fully shut.

    Still waiting for you to qualify why you think boost is an economy improvement but for some reason Ford opted not to use it at any load level ( which in reality they did ). And in addition, why is Ford's 'inefficient' design more efficient than a DI V8 with the same torque?
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    Wwest's method:

    Learn the name of an automotive component, and without ever trying to learn it's function, make up details about it.

    Then build this fantasy system with every new component you learn the name of, never once hitting the mark on what the first did, and therefore creating a system in fantasy that does the complete opposite in reality.

    So in wwest's head: turbo-DI vehicles are inefficient low-compression NA engines (for no apparent reason) that 'switch' to FI. :confuse:

    Here in reality: FI is the entire intake/exhaust flow, except in overboost circumstances when exhaust may be vented to wastegate, and intake to blow-off.

    Ford used an efficient system in it's MOST EFFICIENT ENGINE for it's torque. ON THE HIGHWAY.

    Kinda hard to be grossly inefficient and yet the most efficient engine there, wwest. Why haven't you spent 1 modulated brain pulse on this idea?

    What wwest has to back his claims up:
    He can name parts in an engine.

    What the rest of us have to prove wwest is not thinking clearly:
    EcoBoost engines are most efficient in their torque classes
    The real definitions of these components.
  • wwestwwest Member Posts: 10,706
    I don't think I have ever said that the turbine doesn't continously spin with the engine running, just that it doesn't spin at a high enough rate to generate any significant amount of boost.

    And the thing about centrifical blowers, compressor wheels, is that they are NOT positive displacement. What that means to you is that the compressor could be completely stalled and there would probably still be enough airflow around the compressor wheel to run the engine in cruise mode.

    If you would rather continue to spout untruths I can't be of any help. But if you lack the $12 to sign yourself up for access to motorcraft service and read the actual Ford documents I'd be glad to arrange that for you.
  • wwestwwest Member Posts: 10,706
    "..and make up details about it.."

    Yes, I will willingly admit that most of what I have said earlier on was more of a guess, based on logic, but a guess none-the-less.

    But I found it extremely interesting that when I found and read the actual Ford documents at motorcraft services I found my "guesses" to be fully correct.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    I don't think I have ever said that the turbine doesn't continously spin with the engine running, just that it doesn't spin at a high enough rate to generate any significant amount of boost.

    Why would it need to be 'significant?' Significant boost is applied to significant load and significant fuel. What part of "proportional" that I was repeating did you not catch? Small load, small fuel, small boost? Remember that? Proportional? Hello?

    Nobody said it needed to be significant boost to burn small amounts of fuel. The very fact you are admitting it is miniscule boost is not contrary to my point in any way. I said specifically that the boost is proportional to fuel burned. And at highway loads, that is not in any way a 'significant' demand for air.

    This minute and appropriate amount of FI is automatically provided via the turbos as a result of combustion. There's no way around it, and that's why I keep reminding you that the turbos always spin as fuel is burned. Slowly when a little fuel, and quickly when a lot. That is the whole argument. If you stopped contradicting yourself in thinking that anyone said light loads create significant boost, then you'd be all caught up.


    Yes you did, you said it was 'on/off' and 'clutched in'. Mistaking it for that which is used on 2-stroke diesels. Your guesses were NOT based on logic, nor are they logical now. You are still guessing based on the wrong Wikipedia description of 'clutched-in' turbos used on 2-stroke engines.

    Now you've discovered that electronics are involved. Whoop-di-do.

    The only un-truths that have been made here is that turbochargers are 'on/off'. They most certainly are not. They are more properly termed 'variable speed.'

    And they do most certainly apply to highway speeds in a vehicle as large as a pickup truck.

    I KNOW FOR A FACT YOU READ NOTHING WHATSOEVER THAT CLAIMED THE TURBOS WERE NOT SUPPLYING USEFUL LEVELS OF BOOST AT HIGHWAY LOADS.

    You are simply contradicting yourself on what a highway load is.


    the compressor could be completely stalled and there would probably still be enough airflow around the compressor wheel to run the engine in cruise mode.

    This is a guess and you know it. In reality, having 10' of pipe, an intercooler, and a compressor wheel in the way of the intake is not conducive to any 'lean burn' scenario without partial pressurization.

    The tortured intake path which purpose is to get air to the compressor and through the intercooler, also mandates that the air be compressed and intercooled (slightly) just to reach the throttle in quantities necessary to maintain lean burn.

    THE COMPRESSOR WHEEL IS ALWAYS SPINNING BECAUSE THE EXHAUST WHEEL IS ALWAYS PRESSURIZED BY THE EXHAUST VALVING OF THE PISTONS.

    In short, FI engines are designed to be FI. Not 'on/off'

    In reality, highway speeds represent load. And it goes to light boost dozens of times per mile in highway cruise. You have nothing that says otherwise.

    Be my guest. I know you're just going to pull up that:

    the PCM modulates the throttle and boost settings.

    Again, just because you learned that there are electronics involved doesn't make your claims any less ignorant.

    THAT IS NOTHING CLOSE TO SAYING THAT THE TURBOS CAN BE SHUT 'OFF'.

    Nor is your point ever going to be made of "why 'ask' the compressor to boost and intercool all inlet air."

    At the time you said these things, you didn't even realize that ALL intake air was coming through the compressor and intercooler.

    THAT is what the argument is about. That somehow this system can 'clutch' to naturally aspirated? NO. It can go to very low pressurization, or high pressurization. But there is no alternate route for the intake air to take, and the exhaust wheel is not 'braked' and therefore will always be providing some pressurization.


    That very language validates MY point not yours.
  • wwestwwest Member Posts: 10,706
    If you browse the various Ecoboost tuner forums you will discover some frustration since they are discovering that the PWM solenoid signal is either 0% or 100%, Wastegate fully open or fully closed. Closed but now subject to overboost pressure over-ride opening.

    I like the way you adlib and accuse me of "thinking" that turbocharged engines have an alternate inlet air path other than the leakage around the compressor wheel.

    I can't say that any such thought ever entered my mind.

    With the wastegate fully open and the engine running only in cruise mode, (~14.7:1 A/F mixture) which of the 2 contributes most of the energy to turn the turbine shaft? 1, the force of intake airflow against the compressor wheel, or 2, the small portion of the moderate volume exhaust gas that's not flowing through the fully open wastegate.

    Let's be certain about something. It is my belief, FIRM belief, that the Ecoboost engine operates in normally aspirated mode at constant speed cruise on level terrain.

    Nothing else makes sense.

    Believe what you like otherwise.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    With the wastegate fully open and the engine running only in cruise mode, (~14.7:1 A/F mixture) which of the 2 contributes most of the energy to turn the turbine shaft? 1, the force of intake airflow against the compressor wheel, or 2, the small portion of the moderate volume exhaust gas that's not flowing through the fully open wastegate.

    FACT: the moderate volume exhaust gas that's flowing through the CLOSED wastegate.

    Where did you specifically read that your 'guess' was correct? Wastegate going 100% open or closed still does not validate that Ford did the OPPOSITE of what every other wastegate does, and stays CLOSED 98% of the time. Wastegates open post-boost to prevent boost surge and overboost. Everything you read validates that, you're just interpreting it wrong to meet your agenda.

    Even this:
    &#147;We control the boost to make sure that customers don&#146;t recognize when the boost is building,&#148; said Kunde. &#147;As the turbocharger spools up, the electronic control system takes over. Our active wastegate control, along with the throttle, controls the boost and torque levels very precisely, and the customer perceives a continuous delivery of torque.&#148;

    Does NOT imply that the wastegate starts in the open position. Nor does anything here imply WOT.

    NOTHING here implies that there is ANY benefit to not giving 100% of the exhaust energy to the turbine unless preventing boost surge or overboost, as I've already said, as does the definition of a wastegate.

    Even if the electronic wastegate signal is open/closed, you still made the grievous error in assuming this is the same as turbo on/off.

    You are not arguing from an advantaged position here. You had to back up and cover your tracks on the turbos being on/off, to now you acknowledge they turn a bit. Progress is key ;)


    The normal operation of a wastegate is closed, to allow the turbos to spool freely.

    I like the way you adlib and accuse me of "thinking" that turbocharged engines have an alternate inlet air path other than the leakage around the compressor wheel.

    I can't say that any such thought ever entered my mind.


    No, I'm not accusing you of thinking. Nor will I ever make that mistake.

    You are, however, still wrong about normal functions of wastegates. And since the turbine WILL BE SPINNING, and I have it in writing that:

    Turbocharger &#147;whoosh&#148; is mitigated by electronically controlled anti-surge valves that proactively relieve the boost in the intake, which can range up to 13 psi. Careful software calibrations manage the pressures in the intake manifold.


    Which means, to you, that I was right about pressure being regulated in the intake, POST-COMPRESSOR. And what 'seemed to you' like a chance for the compressor to 'overheat' was a load of B.S.

    Let's be certain about something. It is my belief, FIRM belief, that the Ecoboost engine operates in normally aspirated mode at constant speed cruise on level terrain.

    Nothing else makes sense.


    Yeah, to you. That's a problem with your definition of 'logic'.

    Nothing about your notion of an FI engine running in 'NA mode' makes sense, other than you want to somehow paint Ford's engine technology as the 'inefficient option.' That's how you started with your guessing, and has been your agenda all along.

    Here's the problem: ITS THE MOST EFFICIENT ON THE HIGHWAY IN ITS CLASS.

    SO IF YOU WANT TO PAINT 10:1 COMPRESSION N/A AS MORE EFFICIENT THAN YOUR BELOVED 11.5:1 GM 3.6 (Not 12:1 or 14:1 as you claimed) THEN YOU ARE SUCCEEDING.

    That does not make 'sense', as you are defining it. It's either more efficient on the highway because its FI, or because 10:1 is close enough to ideal. Now what are you going to pick?
  • wwestwwest Member Posts: 10,706
    Maybe I wasn't plain speaking enough...

    I no longer give a damn what you think or know.



    73's
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    "Nothing else makes sense than an FI engine running in NA mode."

    Why?

    Here's what you seem to grasp about the engine:

    1) its 10:1 compression makes it ideal for FI, NOT for NA.

    2) it has low-displacement turbos designed for low-end torque (read: spool at low rpms).

    3) you seem to be grasping (finally, after back-tracking) that air vented out the exhaust will spin the turbos even at idle and low load.

    4) a wastegate reduces spool and pressure (you're contradicting yourself here, since you're saying 'useful' boost is not available, but yet there would be some reason to open the wastegate? why? )

    So why exactly are you insisting there is any purpose, benefit, or reason that Ford would choose wastegate open as its default?

    Why do you feel that FI engines are chosen to go to vacuum, rather than making the most of a spinning compressor wheel? (vacuum caused by opening and closing of valves is how I define Natural Aspiration)

    I mean the pressure at the throttle plate could be 'effectively' zero, like 'ram air' levels on NA vehicles. But why would you want the engine to create negative pressure post-compressor, rather than positive pressure on an 10:1 engine?

    if you're claiming the intake isn't drawing much air and the exhaust isn't putting much out at 'cruising speeds' .... WHY THE HELL WOULD YOU OPEN THE WASTEGATE? !!!

    I mean the only thing it would do if it worked your way is just slow down the spool time, the complete opposite of desireability. Seems superfluous in every way to even have a wastegate by your definition.

    I mean why did you even define a wastegate as something that opens so an FI vehicle can go 100% NA? Every bit of pressure at the exhaust wheel would 'ease' the path of the intake air at a minimum. What's the point in 'clutching off' any amount of FI, even if it were miniscule?

    Why are you claiming that there is any engineering benefit to reducing any amount of available pressurized air by simply having a wastegate? It's like you've invented a third nipple for Ford.

    I, however, can give good engineering reason why there's a wastegate: to remain typically closed, and opened to prevent overboost, as the DEFINITION implies (and nowhere is it stated for racing purposes only, that's the actual purpose).

    You seem to be able to piece engine components together in your head, but did you spend one modulated brain pulse on your actual argument?

    I mean when you break it down, it sounds rather absurd for no apparent reason. Do you have a better strawman of your argument? Any better explanation for believing that the MOST EFFICIENT ENGINE IN ITS CLASS is doing something horrendously wrong (as you implied when I first read your posts).

    If boost good for FI, why FI default wastegate open no boost? Me not clear on what you thinking!
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    All I'm doing is pointing out your argument:

    You're saying:
    - Forced Induction engines are intentionally set up to be Forced Induction through the compression ratio

    Check.

    - FI engines are most efficient when the Induction is Forced (positive pressure post-compressor).

    Check.

    -but FI engines are equipped to go to NA by default (negative post-compressor pressure), rather than scrounging for every last Pa of pressure.

    Che... wait, wha? Huh? :confuse:

    It's not about what I think. You contradict yourself. I just point it out.

    Believe what you will. :sick:
  • bigmclargehugebigmclargehuge Member Posts: 377
    Cool! But that belongs on another thread.

    I don't see how you having an affinity for NA means Ford's EcoBoost engineers would sabotage their FI engine by increasing spool time and reducing post-compressor pressure unnecessarily.

    Seems like you started with a pro-NA agenda and kept at it before you even understood FI to the fullest degree.
  • wwestwwest Member Posts: 10,706
    My best guess is that the EcoBoost engine's turbo wastegate is PWM solenoid "commanded" to remain wide open until the gas pedal position approaches mid-point. At gas pedal mid-point the throttle plate is now WIDE OPEN. Now, as the gas pedal is farther depressed then rising boost pressure is PWM solenoid commanded to increase engine torque in a linear fashion.

    At gas pedal mid-point, WOT, the N/A engine mode is producing all the "GO" that it possibly can. Now, with WOT, LOTS of "waste" exhaust gas pressure, the turbo can be quickly spun up to whatever level of boost is dictated by the gas pedal position.
  • bigmclargehugebigmclargehuge Member Posts: 377
    Sports Car Purists continually disappoint on intelligence when talking about technologies they don't want to see come to dominate the market.

    Seems every time engineering ignorance gets posted, it's another purist that wishes to remain ignorant, yet have an opinion. :lemon:
  • wwestwwest Member Posts: 10,706
    edited October 2011
    Wrong again..!!

    I have long been a champion, and continue to be so, of the....

    West/Otto/Atkinson/Miller multi-mode 4 cylinder boxer engine.

    Basically the combined use of Toyota's E-VVT-i and a positive displacement SuperCharger.

    Toyota is currently making use of E-VVT-i, EXTENDED VVT-i, to shift the RX450h engine operating mode from Otto, 13:1 base/native compression ratio, to Atkinson mode, effective CR of 10:1.

    Toyota's idea is to run the engine with the highest CR possible, highest efficiency, for low cylinder fills, and then switch to Atkinson cycle mode, 10:1 effective CR, as demand for torque, higher cylinder fills, climbs.

    In the mid-fifties Studebaker used an SC driven by the engine via a CVT.

    My "spin" on that is to use a PSD(CVT) to spin the SC. The engine would be one input to the PSD and an AC synchronous 5-7 HP motor(***2) the other. With a solid state variable frequency multiphase inverter driving the AC motor.

    Like the EcoBoost turbo, the SC could be made to simply "idle" along, only supplying atmospheric pressure against the throttle plate, unless the driver depresses the gas pedal beyond mid-point.

    1. Otto mode for "low" cyclinder fills.
    2. Atkinson cycle for moderate cylinder fills.
    3. Miller cycle mode for non-oxygen sensor feedback operation.

    Otto mode, 13:1(***) compression ratio, would represent no threat of knock/ping with the partial cylinder fills.

    As torque demand climbs and the cylinders are being filled to the point of possible knock/ping (detonation) the E-VVT-i system would delay the intake valve closing to the point of reducing the effective CR to 10:1.

    Need more GO..??

    Depress the gas pedal beyond mid-point, WOT, and the PSD begins spinning up the SC.

    Since an Atkinson cycle engine does not leave enough "waste" in the exhaust path for spinning a turbine a turbocharger is out of the question, thus an SC.

    ***1. 15-17:1 base/native CR w/DFI

    ***2. Inverter/motor roughly equivalent to the electric A/C drive in the RX450h/Prius
  • wwestwwest Member Posts: 10,706
    to mention that with an SC configuration as described no actual throttle plate would be required.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    Depress the gas pedal beyond mid-point, WOT, and the PSD begins spinning up the SC.

    That's super.

    But the EcoBoost does not work in the way you describe AT ALL.

    I have no idea why you would try to invent the process in your head, rather than learning how it really operates.

    There is no NA mode up to half 'pedal position'.

    I am not 'wrong again' on this application, nor was I wrong a first time.

    You are out of your mind if you think that the 'pedal position' needs to go to 1/2 or above to yield 'useful' boost. More like 1/10th or above.


    And you are greatly exaggerating the amount of 'cylinder fill' it takes to spool a turbo, expecially since this FI engine is designed to maximize the ratio of FI to fuel as often as possible.

    I mean you're insisting that the amount of fuel to move 5600lbs of vehicle (at even mild accel) is not enough to rotate a tiny windmill in the exhaust stream enough to turn a tiny intake fan at 'useful' speeds? All available evidence implies the opposite.

    Again, I will take that bet. Any time you want to lose money, we can hop in a turbocharged vehicle with a boost gauge, and it will be quite plain that it boosts a dozen times per mile on the highway,


    THIS NA MODE YOU HAVE THEORIZED DOES NOT EXIST IN THIS VEHICLE, AND MOST CERTAINLY NOT TO ANY 1/2 PEDAL POSITION.

    There are a dozen ways I can prove it. Your guesses are 100% the opposite of reality.

    You are champion of making a fool out of yourself on this thread, and like a chicken without a head, just haven't realized the thinking part isn't working anymore.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    I have long been a champion, and continue to be so, of the....


    This is starting to sound a little looney... sorry, had to say it.

    So your ego is going to prove your right on all topics? No, sorry. Doesn't work that way. Obsessed with yourself? Yes. Obsessed with NA? Probably? Smart about turbocharging? HELL NO, YOU ARE NOT. :P

    If you want to invent something, I encourage you to do so.

    I have 2 automotive patents pending, and a few more I am debating. It's a worthwhile 'bet' for the future.

    But this 'bet' of how the EcoBoost works, sorry pal, you would lose that face-down.

    You have been wrong from your first post on this thread, and continue to be so. Your 'best guess' sounds like it might be an idea worth pursuing, but it is a pathetic understanding of the idea that Ford went with.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    As for details on the new design, GM said in a statement, "They will feature lightweight design and advanced technologies such as direct injection, turbocharging and alternative fuel compatibility" as well as being "designed to reduce noise, vibration and harshness."

    Looks like Ford did it right with the EcoBoost.

    These new 1.0 - 1.5 L engines will not be used primarily for towing, nor for racing.
    And yet they are turbo-DI for efficiency.


    Just like the EcoBoost, they will attempt to maximize the time on FI, minimizing the time the turbo wastegate is open.

    They will not be 2 different engines (NA and then FI) for being more efficient or faster than equivalent NA engine, they will manage to be both simultaneously but pressurizing the intake charge at all times fuel is burned. They will deliver torque from boost at the slightest touch of acceleration, just like the EcoBoost.

    They will also likely be significantly more efficient than NA engines of the same torque class, city and highway, just like the EcoBoost.
  • wwestwwest Member Posts: 10,706
    "..They will deliver torque from boost at the slightest touch of acceleration, just like the EcoBoost..."

    slightest touch of acceleration, just like the EcoBoost...

    That's EXACTLY what I've been saying all this time.

    Our disagreement seems to be concerning just how or when the PCM switches modes from N/A to boost.

    It is my opinion that the PCM makes the switch from N/A mode to boost mode whenever the computation indicates that the N/A mode cannot provide the desired level of torque for acceleration, or ever maintaining the current speed up an incline.

    That's why Ford makes such a strong point about DBW non-coupling of the throttle plate and the gas pedal. The gas pedal position often does not correlate to the throttle plate position.
  • wwestwwest Member Posts: 10,706
    "...And yet they are turbo-DI for efficiency...

    No current turbocharged engine, NONE, can be made to be efficient for both cruising, N/A mode, and boost mode. To accommodate BOOST when it is needed the engine's base/native CR MUST be detuned.

    That's why ALL non-DFI turbocharged engines have less than maximum compression ratios, ~8:1, when N/A engines have ~10:1. So the detuning of the engine via reduction of the CR from optimal results in loss of fuel consumption efficiency ~98% of the time driven.

    DFI opens the door to the use of 12:1 compression ratio, or better. While other makes have chosen to use the opportunity to improve FE, Ford has used the opportunity that represents to provide for turbocharger BOOST.

    High engine efficiency only 2% (or less) of the time driven.
  • wwestwwest Member Posts: 10,706
    "...$1? $1000? Because I'm all in,...."

    Let's be fair about this, I'm not comfortable taking your money unless I know you have good, solid, foundation for your side of the bet.

    Sign up to read the official Ford documents at motorcraftservice.com, then send me your user name and password as/for proof that you have read the pertinent material, and then if you still wish to "risk" $1000 we'll go forward.

    I promise to do nothing with the access but verify the account exists.
  • dieselonedieselone Member Posts: 5,729
    edited October 2011
    DFI opens the door to the use of 12:1 compression ratio, or better. While other makes have chosen to use the opportunity to improve FE, Ford has used the opportunity that represents to provide for turbocharger BOOST.

    Duh, a pickup truck setup for towing needs more power (primarily torque) than a N/A 3-4L v6 can produce. Show me a DI 3.5 or so liter v6 that can produce 400+ ft-lbs of torque?

    For example. Porsche's 3.8 flat 6 in a 911 with DI and 12.5:1 compression produces an impressive 408hp@7300 rpm. That's great for a sports car, but the torque output is only 310 ft-lbs at 4200rpm. While that's still impressive, in a 6lb truck that is rated to tow up to 11klbs + it would be weak compared to the 420ft-lbs the 3.5EB produces at 2k-rpm. Bottom line, if you're going to use a small displacement engine, boost is needed to produce big displacement torque.

    Plus the 911 is only rated at 19/26 mpg. Barely more than a EB Taurus SHO which weighs over 1000lbs more not to mention the differences in aerodynamics. Granted, I expect a 911 isn't geared more max FE.

    Even Lexus' LS 460 AWD with a DI 4.6 v8 can't match power and efficiency of a Taurus SHO. The cars are similar in size with the Lexus being a bit longer and a few hundred pounds heavier. Mileage for the Lexus is 16/23 vs. 17/25. But the LS does have an 8 speed trans vs a 6 speed for the Taurus. I guess I'm missing where the extra economy is suppose to be.

    Sure a atkinson cycle engine can improve efficiency. But it comes at the expense of power density. The 3.5 atkinson cycle v6 in a RX450 only produces 295hp with the help of the electric motors in hybrid drive. Hwy mileage is only 28 mpg. That's only 3 mpg more than the RX 350 with it's conventional port injected 3.5 v6.
  • wwestwwest Member Posts: 10,706
    "..than a N/A 3-4L V6 can produce.."

    Which begs the question....what's wrong with a 4L DFI V8 with 12:1 CR in comparison...?
  • dieselonedieselone Member Posts: 5,729
    edited October 2011
    Which begs the question....what's wrong with a 4L DFI V8 with 12:1 CR in comparison...?

    Nothing is wrong with a small displacement v8. But none of the 4-5L DI v8s currently available produce as much torque at a low rpm vs. the 3.5 EB used in the f150.

    Infinity uses a 5.6L DI v8 in the QX 56. It produces more HP but still produces less torque vs EB. Even though it uses an 8 speed transmission it still doesn't match the FE of a 4x4 F150 with the EB. It's rated 14/20 vs 15/21 for the F150.

    My maiin point is the EB pretty much says what Ford claims. It produces big v8 power while returning near v6 levels of FE. I've yest to see a N/A 3 to 6 liter engine that can produce the same amount of torque at a low rpm. Or offer substantially better FE in a similar sized vehicle.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    I'm in for 15,000.

    You're not getting any passwords. Why don't you just quote some language (without any of your spin, HINT: or paraphrasing: HINT) and I'll confirm I'm comprehending what it means ( better than you are at least ).

    The bet is: 5000 says you are wrong about needing to go to 1/2 'pedal' position (or anywhere near it) to go on boost.

    5000 says you are wrong that the truck does not mildly boost at mild acceleration on the highway (up hill, using cruise 'accel' function to pass a slightly slower vehicle).

    And a bonus 5000 if I'm 2-for-2 on those, which would prove you have no understanding whatsoever about how turbocharged vehicles operate.

    And if I dont go 2-for-2, the bonus pool is yours.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    No current turbocharged engine, NONE, can be made to be efficient for both cruising, N/A mode, and boost mode. To accommodate BOOST when it is needed the engine's base/native CR MUST be detuned.
     
    That's why ALL non-DFI turbocharged engines have less than maximum compression ratios, ~8:1, when N/A engines have ~10:1. So the detuning of the engine via reduction of the CR from optimal results in loss of fuel consumption efficiency ~98% of the time driven.


    Wrong on all counts.

    First off, that is not the 'maximum' compression ratio. There are high-strung engines with way more than that.

    Second, many DI NA engines do not have CRs of 12 or 14. Some are more like 11 to 11.5.

    There's a difference between an ideal for the application and always going for the maximum of one overrated statistic.

    Third, many modern non- DI forced engines had CRs way above 8:1. There is actually a lot more overlap.
    The non-DI Porsche 996 turbo had a 9.4:1 CR. See, i actually use examples. You should try QUALIFYING your statements without your personal bias some times.

    CR is not the holy grail of real-world fuel economy.

    You don't understand that pressurizing the intake charge alone causes fuel to burn as completely as an engine that relies on vacuum alone, thus improving it's efficiency over relying on compression ratios alone.

    The pressurized charge is compensating for the compression ratios.
    That's not that complicated.

    All highway turbo-DI engines go to boost under mild loads, and thus many of them manage to be more efficient than NA engines at any torque output.

    They are pressurized 10:1 engines. They are NOT naturally aspirated engines up until the NA portion has 'torqued out'.

    I am not arguing that electronic wastegate modulation occurs to smooth out boost surge,

    But they are designed to spool quickly, under minimal load, so that the pressurized charge works to burn fuel completely.

    It greatly outweighs compression ratios alone as an efficiency booster. Engines are getting more torque at lower RPMs with higher efficiency is no accident. It's the point of FI for this application.
  • bigmclargehugebigmclargehuge Member Posts: 377
    edited October 2011
    The objective of a turbocharger, just as that of a supercharger, is to improve an engine's volumetric efficiency by increasing the intake density. The compressor draws in ambient air and compresses it before it enters into the intake manifold at increased pressure. This results in a greater mass of air entering the cylinders on each intake stroke. The power needed to spin the centrifugal compressor is derived from the high pressure and temperature of the engine's exhaust gases. The turbine converts the engine exhaust's potential pressure energy and kinetic velocity energy into rotational power, which is in turn used to drive the compressor.

    A turbocharger may also be used to increase fuel efficiency without any attempt to increase power. It does this by recovering waste energy in the exhaust and feeding it back into the engine intake. By using this otherwise wasted energy to increase the mass of air, it becomes easier to ensure that all fuel is burned before being vented at the start of the exhaust stage. The increased temperature from the higher pressure gives a higher Carnot efficiency
    .
  • bigmclargehugebigmclargehuge Member Posts: 377
    Much of the energy of the down-stroke of an NA engine is wasted energy.

    Vacuum is drag on the cylinders.

    An FI engine will attempt to boost at ALL RPMs in order to attain a 100% volumetric efficiency.

    It's there in black and white. That's the theory of FI. Everything you've claimed on this thread has been wrong. Stop wasting everyones time, including your own.
  • wwestwwest Member Posts: 10,706
    edited October 2011
    "..The pressurized charge is compensating for the compression ratios.."

    EXACTLY...well stated, VERY well stated.

    Slight correction: The intercooled pressurized charge is more than compensating for the otherwise "sub-standard" compression ratio.

    EXCEPT: when the engine is running off-boost, idle or simple cruise.
  • wwestwwest Member Posts: 10,706
    edited October 2011
    What is wrong, locically thinking, with the DBW throttle plate being fully open at mid-point (or thereabouts) of the gas pedal, and then boost, "calibrated boost", used to raise the engine torque in conjunction with more depression, incremental depression, of the gas pedal..?

    In the alternative, how would you provide for a reasonably linear rise in engine torque as gas pedal depression increases given the parameters involved....???
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