Dynamic Cylinder Deactivation

[MetroMPG]

Also, I am removing blatant "marketing" language from your previous posts. You are welcome to post technical information about your ideas. You are not welcome to use this forum as a sales channel.

Please see this thread:

http://ecomodder.com/forum/showthrea...uel-15251.html

[MetroMPG]

I'd also like to ask everyone to please keep the discussion in this thread civil.

We can be skeptical about something or disagree with someone without resorting to hostility.

[Frank Lee]

Been patiently waiting for a cohesive explanation for how it works that addresses the objections based on current state-of-the-art, to no avail. The thread ceased to be relevant long ago because of that...

[Heihetech]

Originally Posted by MetroMPG

Heiheitech:

You appear to be ignoring a potentially critical question (asked several times) regarding the impact your product will have on OBD-II engine management.

It seems reasonable to expect the car's stock computer will not like what is being done under your approach.

Have you registered your product with the U.S. EPA?

That's right. OBD-II will report "mis-fire" when DCD IS ON. But this is only a
computer code, not a real engine trouble. It will not kill the engine, not kill
the driver and the vehicle. My DCD controlled vehicle has run over 3 years
without other problem. The code gives us the info "DCD runs OK!" and MIL
blinking means "DCD in Progress." The code can be cleared at any time easily
whenever you want, totally worry free.

So OBD-II code that makes trouble should be ignored, so as any related
comments and topics. EPA may not like this, but their software should be
modified accordingly to get rid of the "trouble" by code. DCD don't make
any trouble, but OBD-II code does. So please ignore it and stop talking it.

[MetroMPG]

It seems like this malfunction indicator light / check engine light problem may be an issue in terms of legally selling / installing your product in the USA (as an aftermarket add-on). I'm sure you know this already.

Can the OBD system be repaired, deactivated, or modified?

The rule of thumb when it comes to emissions-related vehicle repair is that any modification that changes the vehicle from a certified configuration to a non-certified configuration is considered tampering: this applies to both vehicle owners and repair facilities and is, therefore, a Federal offense. Replacing a catalyst with a straight pipe is one traditional example of tampering.

Likewise, overriding the OBD system through the use of high-tech defeat devices or non-certified computer chips, for example, would also be considered tampering. The OBD system may, however, be repaired back to its original certified configuration with certified "performance chips" or appropriate aftermarket parts.

Source: Frequent Questions | On-Board Diagnostics (OBD) | US EPA

I wonder if the EPA would consider this modification to be a "non-certified configuration".

[GottaCruise]

Originally Posted by Heihetech

That's right. OBD-II will report "mis-fire" when DCD IS ON. But this is only a
computer code, not a real engine trouble. It will not kill the engine, not kill
the driver and the vehicle. My DCD controlled vehicle has run over 3 years
without other problem. The code gives us the info "DCD runs OK!" and MIL
blinking means "DCD in Progress." The code can be cleared at any time easily
whenever you want, totally worry free.

So OBD-II code that makes trouble should be ignored, so as any related
comments and topics. EPA may not like this, but their software should be
modified accordingly to get rid of the "trouble" by code. DCD don't make
any trouble, but OBD-II code does. So please ignore it and stop talking it.

It's nice your DCD mod. is trouble free, but for the average consumer, a check engine light (CEL) is an issue and failure at time of inspection..

The average consumer or enthusiast is not going to "filter" (misfire) DTC codes, vs. an (additional) Diagnostic Trouble Code, not related to your mod on their own..

[gone-ot]

...if it (this system) is being "sold" then it must comply with ALL EPA/NHSTA rules & regulations, and "...throwing misfire DTC codes..." at emission testing times is NOT allowed.

[mwebb]

depending on the system ," misfire " detection by mr computer causes additional events to take place , not the least of which is suspended Mode 6 testing of various components - some systems will disable injectors on the misfiring cylinder , some will prevent the transaxle from shifting "normally" some will revert to open loop and retard ignition timing to limit max power output .
in other words

when your system detects misfire , everything changes , and NO this is not a desirable state or condition for your system to be in

you may have already killed your cat converter , but you will never know as your system can not test for it as testing is suspended by your tampering .

Originally Posted by Heihetech

That's right. OBD-II will report "mis-fire" when DCD IS ON. But this is only a
computer code, not a real engine trouble. It will not kill the engine, not kill
the driver and the vehicle. My DCD controlled vehicle has run over 3 years
without other problem. The code gives us the info "DCD runs OK!" and MIL
blinking means "DCD in Progress." The code can be cleared at any time easily
whenever you want, totally worry free.

So OBD-II code that makes trouble should be ignored, so as any related
comments and topics. EPA may not like this, but their software should be
modified accordingly to get rid of the "trouble" by code. DCD don't make
any trouble, but OBD-II code does. So please ignore it and stop talking it.

[Heihetech]

There are many posts talking about "misfire" caused by DCD. As I have said
before, this is not true misfire due to missed or abnormal burning. Under DCD
control, normal combustion still happens in the cylinder. When the cylinder is
deactivated, there's totally no fuel injected, thus totally no firing but some
mechanical irregularity will happen, let ECU find a "misfire". This is very unfair
to DCD. It's true misfire can cause mechanical irregularity, but mechanical
irregularity during DCD will never mean chemical misfire. So, OBD-II should
better use other way to detect misfire, such as combustion pressure, or gas
expansion by knock sensor. Therefore, OBD-II software must be modified
accordingly, give the way to DCD operation. We all know OBD-II is the law,
but the law is man-made, and could be revised as required. Detecting misfire
by mechanical irregularity has been out-dated, at least not so perfect.

[Heihetech]

Originally Posted by mwebb

depending on the system ," misfire " detection by mr computer causes additional events to take place , not the least of which is suspended Mode 6 testing of various components - some systems will disable injectors on the misfiring cylinder , some will prevent the transaxle from shifting "normally" some will revert to open loop and retard ignition timing to limit max power output .
in other words

when your system detects misfire , everything changes , and NO this is not a desirable state or condition for your system to be in

you may have already killed your cat converter , but you will never know as your system can not test for it as testing is suspended by your tampering .

mwebb, to tell you the truth, nothing you mentioned has happened on my
DCD test vehicle over 3 years. I try to clear the OBD-II code once a month,
every time it shows "071"="misfire", no other real trouble generated. It all
depend on how the ECU is programmed to process the troubles. Many DCD
installed vehicles in China even never report "misfire". So it all depend on the
regulation and the related ECU software ----- a man-made issue.

By the way, how do you know the cat converter have already killed??? By
un-burnt fuel??? NO! This does not belong to DCD. DCD will stop injection
for some time, how does un-brunt fuel go into cat converter??? Or killed by
cool bypass air??? YES! DCD does have lot of bypassing air, but every vehicle
has such action when driver releases gas pedal during deceleration.