Useless technical info/trivia

[aj164]

I thought I'd start a new thread similar to the features/easter egg thread, but specific to information that gearheads and techies would find interesting.

For example, while changing the oil yesterday, I noticed that the A/C compressor has what appears to be a servo attached to the back. If it is, then this is probably a variable-compression ratio compressor -- meaning the compressor adjusts to the required cooling load instead of (the old way) cycling on/off. [OR - this could just be a new type of clutch...]

Another example: What is the electronic device situated in one of the fuel lines (near the oil filter); Is it a sensor of some sort?

 

[Tim Birney]

I thought I'd start a new thread similar to the features/easter egg thread, but specific to information that gearheads and techies would find interesting.

For example, while changing the oil yesterday, I noticed that the A/C compressor has what appears to be a servo attached to the back. If it is, then this is probably a variable-compression ratio compressor -- meaning the compressor adjusts to the required cooling load instead of (the old way) cycling on/off. [OR - this could just be a new type of clutch...]

Another example: What is the electronic device situated in one of the fuel lines (near the oil filter); Is it a sensor of some sort?

If I read my Owner's Manual correctly... ECON mode will shut down the compressor when stopped, and kick it back in again when in transit.

 

[v8volvo]

Little electronic device in the fuel line may be the fuel temp or pressure sensor. Anyone able to confirm this?

 

[TVguy]

Another example: What is the electronic device situated in one of the fuel lines (near the oil filter); Is it a sensor of some sort?

Little electronic device in the fuel line may be the fuel temp or pressure sensor. Anyone able to confirm this?

Ummm, I think so. I just picked up my car from the "stealership" for a simple oil and filter change... As soon as I started up the car the "Check Engine" light came on. The Vag-Com reports that the connection to the fuel-temp sensor is now intermittant. I'm thinking the knuckleheads bumped the wire loose when changing the filter.

That would seem to match up with the description of the location.

 

[aj164]

Good to see this old thread is back! It is a fuel temp sensor. I confirmed this with the Haynes manual. I also confirmed that the AC compression ratio is electromechanically adjustable, so there's variable output in addition to cycling the clutch.

Something else: The DSG adjusts its clutch engagement speed. I notice this primarily when the engine is cold: From a stop, take off on a slight incline (forward or reverse). If the engine bogs too much, it will raise the engagement speed a few hundred RPM and try again.

 

[aj164]

If I read my Owner's Manual correctly... ECON mode will shut down the compressor when stopped, and kick it back in again when in transit.

ECON shuts the compresor off entirely in my car.

 

[Tim Birney]

ECON shuts the compresor off entirely in my car.

You are 100% correct... I mixed my thought processes up.
When Accelleration is in demand, the Compressor shuts down until the demand for power is relieved.
My bad, as the Kids say.