Dynamic Cylinder Deactivation

[morphector]

Your telliing us you've got between 5 to 15% fuel economy, is that on a big v8 on a suv or small 4 cylinder?

[Heihetech]

Originally Posted by morphector

Your telliing us you've got between 5 to 15% fuel economy, is that on a big v8 on a suv or small 4 cylinder?

5 to 15% is from the test based on 4-Cylinder engine, 1.6L 16-valve, 4-speed
automatic transmission, without turbo-charge. Larger engines like V8 or V10
could save even more, due to its power redundency and wider DCD fitness
range. V8 test data is not available now. I'll get you updated sooner or
later.

[Heihetech]

HHO seems an out-dated technology that I fell it is not worth the effort.
Theoratically it's very simple, but to implement an engineering device for
automotive applications, a lot of issures must be considered or solved ----
space to install a big can; battery power to consume; battery get drained;
fuse get blowed; electrical connection; on/off control; pipe connection;
maintain liquid level; low liquid level will reduce current; higher liquid level
will be sucked into the engine, chock engine to die.... a lot of headaches
and hard works yet you get tiny result, and sooner or later, the plates get
corrupted and you need to rebuild the cells.....

DCD with its fully electronic control, has opened a new erea for automotive
fuel economy retrofitting. Once it's installed, it would last forever. The high
reliability of modern electronics will serve you unlimited time.

Therefore, I'd like to recommend that Ecomodders stop playing HHO, turn
to advenced DCD technology instead. Spending less efforts with DCD, yet
you could gain much more than HHO. DCD will absolutely worth the effort.

[t vago]

Originally Posted by Heihetech

To reply "t vago"'s comments below ----

Heat transfer is always bi-directional, so if you think cylinders will be heated
up by coolant, then the heat generated from compression will be transfered
into coolant. This means energy loss into the coolant.

There's a slight difference from the 500 C temperature rise (assuming a 9:1 C/R) from adiabatic compression alone, and a 3000+ C temperature rise from combusting a fuel/air mix. For the brief amount of time that the cylinder is under compression alone, I'd say that heat transfer is negligible. Same goes for the equally brief time that the cylinder undergoes expansion. Oh, you forgot that!

Originally Posted by Heihetech

In case of Traditional Cylinder Deactivation, compression happens TWICE in One ENGINE cycle, so the energy loss will be doubled.

And there's no energy recovered once the compression is reversed? You do realize that for every compression stroke for what you term TCD, there's also a matching expansion stroke? Net energy loss is due to friction and slight pumping losses through the piston rings.

Originally Posted by Heihetech

Nothing is perfect in this world, so my online article and DCD itself is not so perfect, but it does save with very high utilization. Theoratically, as you have analyzed, Traditional Cylinder Deactivation (TCD) seems more perfect than Dynamic Cylinder Deactivation (DCD), but it suffers utilization as one of its killing factors. TCD disables 50% cylinders in the engine, left a power output of 45%. Such power can't be used under most of driving modes. As a resullt, TCD has be off most of the time, becoming useless. There seems always NO sunshine on TCD's "solar panel", where's the benefit?

Um... That power isn't needed under most driving modes?

You also neglected to mention higher peak pressure of the firing cylinders. This is tied to lower vacuum in the intake manifold. Both cause the engine to work less just making itself move, therefore saving fuel.

Furthermore, you neglected to mention that TCD schemes generally work transparently - if a driver needs more power than the engine can provide with half its cylinders shut off, the engine computer will automatically and seamlessly activate the remaining cylinders.

Originally Posted by Heihetech

In contrast, DCD can be turned on most of time, resulting high utilization. The resulted power level will be from 50% to 100% in multiple stages, based on the driving need. It makes a good match between engine power and the load, yeilding maximum savings. There's always sunshine on DCD's "solar panel".

Multiple stages...

Sounds needlessly complicated to me. The auto manufacturers seem to have licked this problem with modern computer controls.

How do you propose to regulate fuel delivery when your oxygen sensor senses an excess of oxygen in the exhaust stream? WBO2 sensors are going to go nuts continually trying to go between a lambda of 1 and a lambda approaching infinity. You do realize that's what's going to happen when your DCD thingy activates, right?

Oh, heck, let's go there, too... Forget about O2 sensor feedback - How do you propose to mask the intentional misfiring of the engine so that the engine computer does not see it, and does not throw the engine into limp-in mode?

Originally Posted by Heihetech

Further, TCD WON'T be applied to general vehicles on the road by aftermarket retrofitting. How does it save fuel in no where? NO WAY

Riiiight. You're trying to sell us on a gadget that intentionally throws a vehicle into limp-in mode by cutting fuel to 1/2 the available cylinders, without describing how exactly the fuel savings is supposed to occur, other than by some nebulous "heat transfer" that would actually put the engine at risk of developing premature wear. You further try to convince us that a true variable displacement system somehow uses more energy to work than your DCD, even though your DCD will actually force the engine to pump more air through it for a given work output than with either a traditional engine or a true variable displacement engine.

It would seem to me that if it were as easy as you claim to reduce fuel usage simply by turning off fuel delivery to 1/2 the cylinders in an engine, that we at Ecomodder would have done so by now. I seem to recall one or more of the other posters in this very thread have themselves experimented with shutting off fuel to 1/2 the cylinders.

Your method of passing emission testing leaves a lot to be desired. There is no way that your system could get CARB approval.

[Heihetech]

[QUOTE=t vago;240003]There's a slight difference from the 500 C temperature rise (assuming a 9:1 C/R) from adiabatic compression alone, and a 3000+ C temperature rise from combusting a fuel/air mix. For the brief amount of time that the cylinder is under compression alone, I'd say that heat transfer is negligible. Same goes for the equally brief time that the cylinder undergoes expansion. Oh, you forgot that![QUOTE]

the 500 C temperature rise? much higher than 100 C coolant temp, high
enough for heat to escape to coolant. When heat comes back during
next expansion, heat source temp is only 100 C. So the loss always larger
than the gain and such loss must have been doubled due to TCD'S action.
The double loss will also be enlarged by all 50% of the cylinders! not only
one or two. Saying negligible isn't correct.

Further, modern strenthened engine would have higher C/R, like 10.5 or so,
then such thermodynamic loss could become larger.

[Heihetech]

There seems a Mr. TCD who keeps saying that DCD is not as good as TCD.
But his knowledge seems coming from thermodynamics only, not from control
electronics. Moderm engine is controlled by ECU, by oxygen sensor, by closed
loop. DCD needs even more controls, by DCD controller, by WBO2 sensor, by
high-lambda loop, by multiple lambda set points. If you don't know all of the
basic knowledges, your comment on DCD could become unreasonable. I won't
teach you everything related to DCD. You may wish go to read some
textbooks before making qualified speach.

I'm talking about the benefits of DCD because I invented DCD, I did my
contribution to this world. What about you, Mr. TCD? Did you join the actions
in 1970s and 1980s in TCD invention? Or you had made any TCD controller
by which TCD aftermarket retrofitting can be implemented. How many TCD
engines have you implemented or retrofitted? Show all of us your qualification.
You sound like a professor of thermodynamics, yeilding top score in this field.
But you should know that's only 1/3 of the engine related knowledge.

DCD technology is chanllenged by TCD and Mr.TCD. DCD is not afreid of TCD.
Let's wait to see who will beat who? who has more installation? who has
higher utilization? who has higher overall fuel savings? Mr.TCD should know
overall fuel savings comes from the contribution of these factors, not the
single one from thermodynamic analysis.

[Heihetech]

Originally Posted by t vago

Furthermore, you neglected to mention that TCD schemes generally work transparently - if a driver needs more power than the engine can provide with half its cylinders shut off, the engine computer will automatically and seamlessly activate the remaining cylinders.

Multiple stages...

Sounds needlessly complicated to me. The auto manufacturers seem to have licked this problem with modern computer controls.

The fact is driver always needs more power than the engine can provide with half its cylinders shut off, so TCD could be ALWAYS OFF. ONLY ON AND OFF!
LOOKS VERY CHILDISH. This is only 2-way entery level control.

TCD diactivates a fixed 50% of the cylinders, which is a number trend to over-deactivation under most of common driving conditions. As a result, TCD could only be activated within a very narrow range to avoid over-deactivation under fixed 50% deactivation. Therefore, its utilization could become very low, as one of its user commented at end of [#] that “The 4-cylinder option (Active Fuel Management) only works when coasting or driving down slope. (It) does not engage or remain ON for level road.” In contrast, DCD could make deactivation ratio variable and well optimized between 0% and 50% to match various driving conditions, being activated most of the time and 100% of the time during city driving mode, yielding very high utilization. Higher utilization means more chance for fuel savings.

Multiple stages... means advanced control and better performance, resulting
higher fuel savings. Why needlessly complicated? Ridiculous!!! You prefer
entery level technology than advanced technology? Then you may wish to
go back to play with steam engine that thermodynamics well applies but
don't need control electronics!

[#] Bill Siuru, Variable Displacement for Better MPG, greencar.com, 10/01/2007
http://www.greencar.com/articles/var...better-mpg.php

[Heihetech]

Originally Posted by t vago

Oh, heck, let's go there, too... Forget about O2 sensor feedback - How do you propose to mask the intentional misfiring of the engine so that the engine computer does not see it, and does not throw the engine into limp-in mode?

Why "Forget about O2 sensor feedback"? I told many times that DCD's fuel
saving secrute is by WBO2 Sensor, which determines the target of high-
lambda control. You may know what is high lambda? It should be much higher
than the unity. Then you may figure out how much fuel would be injected vs
air intaken? You was wrong to expect more fuel injected.

Misfiring? That's a trouble to most conventional engines that needs to be
avoid. But to DCD controlled engines, "misfiring" is what we wanted, it's
the sign of DCD in progress, but don't have real physical misfiring. If you
are afried to see "check engine" light on, I can put it off by program.

limp-in mode? DCD has been tested on real vehicles for over 2-years, and
had, has never "limp-in mode" happened, because no vehicle is designed
so stupid. "check engine" light on and OBD-II codes are enough to present
the trouble. Why make more trouble by limp-in mode? In fact, for many
times I demo my DCD controlled vehicle to passangers, they even don't
know DCD CONTROLL has been changed from off to on to max in multiple
stages, engine still runs smooth under DCD control.

[Heihetech]

Dear Mr. TCD,

To fight bcak your chanllenge from TCD, I'd like to chanllenge your TCD by
DCD with some real physical actions -----

Let's find 2 vehicles with identical make and mode, then you make your TCD
retrofitting, I make my DCD retrofitting, then test driving under the same
conditions, as to see who saves more fuel, thus who beat who.

Next, let's do cross retrofitting ----- I retrofit your TCD controlled vehicle
with DCD; and you retrofit my DCD controlled vehicle with TCD, as to see
who gets higher additional fuel savings beyond the previous retrofitting.

Although you are the winner of thermodynamics, you may not become the
winner of fuel saving technology.

[Heihetech]

Originally Posted by t vago

Riiiight. You're trying to sell us on a gadget that intentionally throws a vehicle into limp-in mode by cutting fuel to 1/2 the available cylinders, without describing how exactly the fuel savings is supposed to occur, other than by some nebulous "heat transfer" that would actually put the engine at risk of developing premature wear. You further try to convince us that a true variable displacement system somehow uses more energy to work than your DCD, even though your DCD will actually force the engine to pump more air through it for a given work output than with either a traditional engine or a true variable displacement engine.

It would seem to me that if it were as easy as you claim to reduce fuel usage simply by turning off fuel delivery to 1/2 the cylinders in an engine, that we at Ecomodder would have done so by now. I seem to recall one or more of the other posters in this very thread have themselves experimented with shutting off fuel to 1/2 the cylinders.

Your method of passing emission testing leaves a lot to be desired. There is no way that your system could get CARB approval.

How do you know "limp-in mode by cutting fuel to 1/2 the available cylinders"?
You designed something like this? or you have got used to turn 50% cylinders
off by TCD that makes vehicle into limp-in mode ?

I NEVER SAY "a true variable displacement system somehow uses more
energy to work than your DCD". That's your original statement. What I said
is TCD will save less fuel than what DCD could save, and part of TCD's fuel
savings will be lost due to certain reason. The smaller saving is still a positive
number, not a nagative number as you argued.

true variable displacement system? Please don't forget DCD controlled engine
is a better true variable displacement system than TCD controlled engine.

passing emission testing problem? Just switch DCD off, everything will go back
to the original. Then no more passing emission testing problem.

turning off fuel delivery to 1/2 the cylinders in an engine? VERY BAD IDEA
ONCE DCD HAS INVENTED. DCD has integrated such function, but DCD
seems never have a need to go to that dead point. The smart guys will
try advenced DCD BEFORE going to try your entery-level skill.