EPA Emissions Regulations Key Factor?

[GerryLP]

By the way,

Some of us have mentioned costs -costs this, costs that. The costs are passed on to the consumer, right? So what other claim can the Big 4 automakers make to use as an excuse?

The automobiles are already doing what they need to be doing -burning fuel more efficiently, capturing almost every source of emission, and monitoring the control of emissions.

Perhaps what the automakers mean by costs is that the cost for this specialized technology can be recuperated through the sales of vehicles like Corvettes and Cadillac's SRS's, but when it comes to the average Joe's economy car and the market at which they are aimed, that investment recovery is almost always in the red.

GerryLP:cool

 

[Hib Halverson]

One must remember that 5 years in engine development time is a huge deal. back when the ZR1 engine was in production it was using OBD1 engine management, now we are into OBD2 and near OBD3 generation with means the computers can manage a heck of alot more engine functions, thus emission dutys. Also technolgy marches on in dealing with catalysts and fuel refinements. Although GM may have been able to make the ZR1 engine live on, I think the cost of the engine may have been the factor the ended it's usefullness. Also one can't discount GM's bean counters as a factor in all of GM decisions in what engine live or die.
But I maybe wrong also.

Actually, today's engine controls do manage more engine functions but...not that many more than did systems like that on the LT5. The big difference between pre-96 OBD and OBDII is the goal of the diagnostics---with OBD, it was simply to detect faults and inform the driver but with OBD II it was to not only detect and inform but, also, to attempt to predict failures of emissions controls devices. Making the system predict failures before they actually take place vastly increased the complexity of the systems.

As for "OBDIII"...hope it never comes.

The earlier discussion didn't delve into the LT5s cost but there is no doubt that, in addition to internal GM politics, the cost of the engine along with its weight were factors in it's demise.

 

[Evolution1980]

...but with OBD II it was to not only detect and inform but, also, to attempt to predict failures of emissions controls devices.

Can you give an example of what the difference is between detect and predict?
Example: I would think that if it detects a bank-1 O2 sensor reading outside the threashold of what's expected from bank-2, that it would predict that the bank-1 O2 sensor is going bad and alert the driver?

Somehow I don't think I'm understanding your meaning of detect and predict.

 

[Hib Halverson]

Can you give an example of what the difference is between detect and predict?
Example: I would think that if it detects a bank-1 O2 sensor reading outside the threashold of what's expected from bank-2, that it would predict that the bank-1 O2 sensor is going bad and alert the driver?

Somehow I don't think I'm understanding your meaning of detect and predict.

Great question!

"Detect", in the context of on-board diagnostics, is to give information to the driver, after the fact, that an emissions related system has failed.

OBDII systems, in some cases, attempt to predict impending failure and will advise the driver either before it happens or as the failure starts to occur. An example is "catylist monitering" which all OBD II systems have the capibillity to do. When the OS2 signal from the rear sensor(s) begins to mimic that of the front sensor(s), the ECM's on-board diagnoostics software assumes the cat is going bad and turns on the engine light.

If you read the explanation of the DTCs in "engine controls" section in any 96 or later Service Manual, you'll find many cases where a code sets as a way of advising the driver an emissions related system is starting to have trouble.

 

[Evolution1980]

When the OS2 signal from the rear sensor(s) begins to mimic that of the front sensor(s), the ECM's on-board diagnoostics software assumes the cat is going bad and turns on the engine light.

Ahhh...gotcha. Dem dere 'puters are gittin' purty smart!
Actually, the logic on it seems like fairly straight forward IF...AND/OR...THEN statements.

 

[NORTY]

Emissions have everything to do with catalytic converter location, combustion chamber EFFICIENCY and burn characteristics.

Speaking of combustion chamber efficiency, has "Direct Injection" been tried on the LS-7? It should help with emissions (& torque too!)

 

[Aurora40]

I beleive so far GM has only used direct injection on some Ecotech and "high-feature" V6 versions.

 

[c4c5specialist]

Direct injection has already been introduced on a few GM vehicles.
Personally, Im SURE its coming, based on the ever tightening emission standards, just like hydrogen vehicles.
So, with that in mind, has it been tried on Gen four small block, I dont know.
Will it be introduced? Im pretty sure that soon you will see it on all vehicles.
Allthebest,

 

[Tyler Townsley]

Can you say a 5/6 ltr V 8 turbo diesel? LOL Wonder what they decided a couple days ago. Seems GM is doing a lot of work on a TD for its light truck line and there is some discussion of using this engine platform in the Corvette. In case one forgets that is where the funding/testing money came for the current LS series of motors.

Tyler