[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.