Can a diesel use a "catch can"?

Here's an ignorant question: is it possible to filter the EGR stream, catch can style? Or any other style for that matter?

I am really torn about the EGR system - I realize its benefits for Nox and cooler combustion, but offsetting that is the apparent nightmare it creates in terms of intake deposits. I'm really tempted to close it off at the exhaust manifold (if I can code it out), but if there were a way to reduce/minimize the deposit formation, that would be a pretty darn good compromise.

I have no idea on your filter idea. But I'd be curious to know if the car is smart enough to know the EGR is being fed nothing. If it is not that smart then no need to reprogram after blocking it. Let it function as it sits after being blocked.

Originally Posted by Snipe656

But I'd be curious to know if the car is smart enough to know the EGR is being fed nothing. If it is not that smart then no need to reprogram after blocking it. Let it function as it sits after being blocked.

I thought about that too. Unfortunately, I think the car is smart enough. From "Advanced BMW Diesel" handbook:

The electric actuating system of the EGR valve enables exact metering of the recirculated exhaust gas quantity. In addition, this quantity is no longer calculated based solely on the signals from
the hot-film air mass meter and oxygen sensor but the following signals are also used:

• Travel of high pressure EGR valve
• Temperature before high pressure EGR valve
• Pressure difference between exhaust gas pressure in the
exhaust manifold and boost pressure in the intake manifold.

This enables even more exact control of the EGR rate.

I forgot to copy the passage, but somewhere else it is explained that codes are thrown if certain parameters are not met. With all that noted, if it were possible to code out the EGR function, then the car would be effectively lobotomized wrt the EGR function, and the blanking would work. At least in theory...

Originally Posted by 62Lincoln

Here's an ignorant question: is it possible to filter the EGR stream, catch can style? Or any other style for that matter?

I am really torn about the EGR system - I realize its benefits for Nox and cooler combustion, but offsetting that is the apparent nightmare it creates in terms of intake deposits. I'm really tempted to close it off at the exhaust manifold (if I can code it out), but if there were a way to reduce/minimize the deposit formation, that would be a pretty darn good compromise.

We have two different types of contaminant between the gasoline and diesel engines. Gasoline cars are pushing vaporized oil into intake via PCV. Diesel cars are pushing carbon and exhaust particulates into the EGR tract. I'm not thinking a "catch can" is made to store up carbon deposits and allow exhaust gases to continue flowing by. I'm thinking the catch can would eventually clog up on a diesel if you were to run with 62 lincoln's question to see if it works.

If the temperature before and after is always cool, due to it being blocked, I wonder if or how the computer would gripe/react. Regardless I am sure one of the two ECU reflash methods mentioned on the forums could make provisions for when doing this.