If this is a FCV (Flow Control Valve), this works with the EGR system.

Sent from my Samsung Note 4 using Tapatalk.

 

I believe that it is an EGR flow control valve that only closes down during idle. That provides some vacuum for the EGR to operate during idle.

 

Ok I see how that works now. Thanks guys, Still have to look into other ill effects of getting rid of the EGR, as DPF loading or NOx issues with the SCR. Its fun to always learn more about our trucks.

 

On the top of egr functionality, this closes when you turn off the engine and cuts the air in the intake, making your engine to turn off without the diesel known shook. Conventional diesels just cut the fuel, but by also cutting the air during engine stop, it allows a more smoother stop, which is desired for non-diesel hard-core customers and your average soccer mom that drives a diesel but does not want the annoyance of a "normal" diesel engine. When egr kicks in, the butterfly closes a bit, to allow egr gases to enter the intake, by limiting the amount of air that would normally go in without the FCV. FCV does not close completely unless you stop the engine, for few seconds, after which onpens again. On full throttle is completely opened. On cold engine is completely opened. When engine warms up, the computer starts to close it, but not completely, this only when the computer knows it can spit the egr gasses in. Without an egr, this would be useless from the point of operation of the engine.

 

Good explanation Thermorex. I think there is a GDE tune in my future. Thanks.

 

Aha, i wonder if my delete tune has put the valve in an allways open pos because i think my engin stops is a bit rough after the tune..

 

Oh man, don't say "starts to go bad". I will be happy to be alive in 5 more years but that "going bad" thing is not high on my list.

 

The throttle valve serves 3 main purposes:
1. EGR flow management in light load conditions where there is not enough delta pressure between the exhaust manifold and the intake manifold to flow the desired EGR fraction. It definitely operates off-idle, depending on the operating conditions of the engine, and can happen both cold and hot.
2. Air flow management during DPF regeneration. In all light- and part-throttle conditions it's necessary to precisely manage the oxygen content and air mass flow rate to keep the regeneration process under control.
3. Shut down. Here the throttle valve closes completely to smooth the shut down process, it's done also to prevent engine mount excursion that leads to premature failure. With EDC17 there's also a soft shut-down function that instead of simply shutting off the fuel instead ramps it down to smooth the shut-down even further.

 

Guys, can you please tell us if the gears on the FCV (if they use gears) are plastic, like on the crd liberty? Just curious on how reliable they will be.

 

Reliability of the throttle valve on this engine isn't an issue, it's a completely different design being an H-bridge DC motor vs the smart actuator on the Liberty.
We believe the internals are still plastic, we would have to cut one open to see.

As a side bar, the one on the Liberty was upgraded over the years with improved internal materials to prevent the teeth stripping along with improved engine controls to prevent shaking of the throttle valve that would over-cycle the teeth and break them.

 

Thanks guys!

 

Ok I always thought diesels don't have a intake butterfly valves. Here is a picture on our diesels and sure enough there is a butterfly valve that's on mine at least and appears to open and close while it was idling with the charge cooler hose disconnected at the Fenn coupling. (I think its called that). I was looking to see if there was any oil blow by from the inter cooler and it was pretty clean. So I conclude that the carbon build up on the MAP sensor I pulled is coming from the ERG system.
So who can explain the function or purpose of this butterfly valve?

Thanks

View attachment 10678

What is the sensor in front of the butterfly valve called?

 

Maybe the CAT sensor. Charge Air Temp.