High pitched whine from behind grill

Hi All, got a call from Land Rover Australia today. They explained to me the whining sound is from EGR valve, which helps to clean turbo diesel engine. Any idea what is this ?

(26-09-2013 11:39am)praj Wrote:  Hi All, got a call from Land Rover Australia today. They explained to me the whining sound is from EGR valve, which helps to clean turbo diesel engine. Any idea what is this ?

Thanks for finding out what the noise was - it's always puzzled me, even though I knew that it was 'normal'.

This is a valve which recirculates exhaust gases back into the inlet manifold to reduce combustion at idle speeds (by displacing some of the oxygen). The main advantage is to reduce nitrous oxides to meet modern emission standards. I don't think they are restricted to diiesel engines, though. I'm guessing that the noise is some sort of continued operation to keep it free of carbon deposits - but how exactly it achieves that I don't know. -

I'm also not sure why you don't get this noise from other car types. However, the engine fitted in the Evoque is pretty old-fashioned, so maybe more recent technology has moved on from this necessity. For an example, I have Volvol Penta D6 diesel engines in my boat, and they run clean enough that they don't even need an EGR system.

(26-09-2013 12:24pm)Donny Dog Wrote:  Thanks for finding out what the noise was - it's always puzzled me, even though I knew that it was 'normal'.

This is a valve which recirculates exhaust gases back into the inlet manifold to reduce combustion at idle speeds (by displacing some of the oxygen). The main advantage is to reduce nitrous oxides to meet modern emission standards. I don't think they are restricted to diiesel engines, though. I'm guessing that the noise is some sort of continued operation to keep it free of carbon deposits - but how exactly it achieves that I don't know. -

I'm also not sure why you don't get this noise from other car types. However, the engine fitted in the Evoque is pretty old-fashioned, so maybe more recent technology has moved on from this necessity. For an example, I have Volvol Penta D6 diesel engines in my boat, and they run clean enough that they don't even need an EGR system.

Sounds like you have something that is less economical than the Evoque diesel. Didn't think it was possible

(26-09-2013 11:39am)praj Wrote:  Hi All, got a call from Land Rover Australia today. They explained to me the whining sound is from EGR valve, which helps to clean turbo diesel engine. Any idea what is this ?

If this is the case, why does it whine before the engine starts and for a couple of minutes afterwards ? What is the EGR doing in these times to make it whine ?

(26-09-2013 01:01pm)speary Wrote:  Sounds like you have something that is less economical than the Evoque diesel. Didn't think it was possible

Less than ONE mile to the gallom, I'm afraid!

(26-09-2013 04:51pm)cjfp Wrote:  If this is the case, why does it whine before the engine starts and for a couple of minutes afterwards ? What is the EGR doing in these times to make it whine ?

Exactly, the EGR valve will open to reduce the combustion temperature by recirculating Exhaust gas into the intake, but the whine occurs before the engine is even running, and valve's don't generally whine. Not saying it's wrong, but it doesn't explain it for me.

I'm a bit late to this thread, having only just bought my (ok the wife's) Evoque last week.

Mine too has the high pitch whine, and I can probably dispel a few theories here.

It's not an inverter, since they convert DC to AC power, not something you have under the bonnet. But PhilSKill you were close.
I doubt it's the EGR valve, as some of you have already realised the engine isn't running, plus the frequency is too high to be a valve opening and closing.

Given the frequency I'm pretty confident it's either a poorly designed switch mode power supply in one of the Electronic Control Units, or a sub standard component on a power supply.
What you're hearing is the switching frequency of the power supply, probably coming from it's inductor.

When the ECU goes into sleep mode it shuts off some of it's internal power supplies, that's why it goes quiet after a short while when you lock the car.

Just because they all do it doesn't make it right and nothing to worry about. Imagine if the power supplies in your TVs and DVD players made a noise like this !?

I'll be talking to the dealer on Monday when I visit them, though I suspect I know more than them and I'll be banging my head against a wall

Hi da22a1,

There is an inverter Ballast under the bonnet to achive the High voltage start-up of Xenon headlights, but since this noise does not relate to the Xenon's, I'd not think it was that. I agree Switch mode power supplies can cause this sort of whine, although this seems extreem for these as they are relatively efficient, but what would require this since there is a good 12-14V stable supply, normally most electronics units will have their own 5V regulators for the electonics to run from Battery voltage, maybe the Electronics/entertainment system is so high current it needs a dedicated regulated power supply and so it's done seperately...? (And hence we get 10 mins to use it with the engine off!)

(07-11-2013 03:02pm)PhilSkill Wrote:  There is an inverter Ballast under the bonnet to achive the High voltage start-up of Xenon headlights...

Doh..! you're right... Xenon lights, completely forgot about those suckers, it could be the transformers in those ballasts after all.
I never noticed the noise on the Pure Tech we took for a test drive which incidentally didn't have Xenons, but mine has them.

Switch mode PSUs are used in some ECUs, due to the need for 5V and 3v, eg 32bit ECUs. Here's an example of one
Automotive Switch Mode PSU

You might also find that some ECUs use step down or Buck regulators rather than linear regulators, being more efficient they get used where they need low quiescent currents. These too are switching devices using inductors that will sing if not properly manufactured.

This has me intrigued, I'm going to have a poke around under the bonnet and try to figure out what module the noise is coming from.

Given that chip would be inside an ECU box (probably metal for heat conductivity), i'd be surprised if it made that amount of audible noise! You don't get that much noise from 240->12v switch mode supplies.

Be great if you can locate what device it is coming from physically though! Get some pics if you can.