TDI Engine: Fully Mechanical with VTG Turbo

Hi,

MWM Brasil offers this engine with a VTG turbocharger.
http://www.nav-international.com.br/default.asp?su=3&pa=series&idSerie=44&idLinha=12

The engine is definitely fully mechanical.

How is the VTG control implemented?

Regards,
Jens.

You can also control the VTG using overpressure.

The danger is that it will no longer be fail-safe. Because the control system needs to be set to "steep" without any pressure. If the control pressure hose breaks, the turbo will overspeed.

m;

The engine was used in vehicles such as the Ford Ranger. It's unclear whether Ford implemented any fail-safe mechanisms. Unfortunately, we can't ask Ford directly, as Ford D only distributes this vehicle and has no knowledge of its technical details.

I don't want to complain, but how important is fail-safe functionality in this case, really?

"Food for thought: Every wastegate charger is pressure-controlled, and therefore has exactly the problem described: If the pressure hose to the wastegate actuator breaks, the wastegate will no longer open, and the boost pressure will increase uncontrollably. This is the same principle with pressure-controlled VTGs. And since most of the older wastegate systems are still in use, I see this as a purely theoretical problem, rather than a practical one, even for pressure-controlled VTGs."

Regards,
Guste.

Hi Guste,

In the typical VTG turbochargers of 90/110 PS TDIs, a completely "stuck" VTG combined with a full injection quantity can result in approximately 1 kg of metal debris entering the intake manifold, intercooler, and catalytic converter. This doesn't happen frequently because the engine control unit immediately cuts off the fuel supply in emergency mode. Without this emergency mode, it would cause a loud "poof."

If you don't believe it, try it out... I _know_ it.

Best regards, Rainer.

Hi Rainer,

I'd gladly believe that a VTG (vehicle traction generator) can fail in the Max LD (maximum load) position if the emergency system doesn't work.

However, I would have assumed that even a wastegate would eventually become metal scrap if it remains stuck open and the emergency mode doesn't function. Therefore, my assumption is that there wouldn't be a significant difference whether it's an overpressure VTG or a wastegate.

I haven't tested it yet, and I won't be able to do so before , even though I have a spare charger on hand.

Regards,
Guste.

And who goes into emergency mode in a fully mechanical engine... besides the driver, if the turbo fails?

m;

guste100 wrote:

But I would have assumed that even a wastegate would turn into metal scrap if the wastegate remains closed and the emergency mode doesn't function. Therefore, my assumption is that it doesn't make a significant difference whether it's an overpressure VTG or a wastegate.

Well, that would be a failure of multiple safety systems.

The 1.6L VW turbos have a pressure relief valve that malfunctions under certain conditions.
Boost pressure control opens, possibly allowing for a (modified) diverter valve.
to be integrated into the charge air cooling system.

As an additional safety measure, at least one boost pressure indicator should be installed.
and possibly, using a valve, cut off the pressure supply to the boost pressure enrichment system.

Best regards, Michael.

The 1.6-liter engines release the boost pressure, but do not prevent its generation.

The pressure relief valve would often activate whenever the turbo was slightly increased in boost on the JX (by adjusting the wastegate membrane screw).

m;

Hello,

dieselmartin wrote:

The 1.6 engines release the boost pressure, but do not prevent its generation.

Ultimately, yes, because when the device activates, the pressure drops suddenly, and the boost pressure enrichment stops, resulting in less exhaust energy -> which means less pressure is generated. You could also say that the turbocharger's rotational speed doesn't increase completely uncontrollably.

Quote:

The pressure relief valve would often activate whenever the turbo was slightly increased in speed on the JX (by adjusting the wastegate membrane screw).

You can adjust it to close, and it will then be sealed up to approximately 1.1 bar relative. It's extremely dangerous if it opens up during overtaking. I replace the spring with a piece of oil pipe, and then it will definitely always be closed . The wastegate turbos won't break immediately just because they've been operated at 1.3 bar for a few years ; so, that thing is rather unnecessary. VW eventually realized this too, and they removed the valve in the 1.9 TDI engines and in the 60HP soft-TD models.

Best regards, Uli.

The 1V and AAZ engines don't have that annoying valve, and they run fine without it .

Hello,

What did I write there last week?

Uli S. wrote:

Wastegate chargers don't necessarily break just because they've been operated at 1.3 bar for a few years

.

Just when I open my mouth , something like that happens to me :
Garrett T2 turbocharger, originally used on a Seat Toledo with the AAZ engine for 300,000 km with its original setup. Then, it was used on a 1.6L engine in a Passat 32B for about 30,000 km, running unregulated (1.5-1.6 bar) until the crankshaft broke. It's been back on the 32B for about 20,000 km, running at 1 bar. For a few days, it's been making a whining noise. I wanted to check if there was a leak in the charge air system, but I haven't had the time (I'm lazy...). On Friday, the whining was accompanied by a loud screeching noise when revving, but it still built up pressure as quickly as usual. The pressure was fluctuating slightly (6-8 bar) in the upper part of the load range, but full load was normal at 1 bar. Oil consumption is unremarkable, but there's a slight oil smell in the exhaust. At home, I removed the intake hose and noticed about 0.5 cm of axial play.
Now, a water-cooled T2 from SB is coming up for sale.
Basically, I can't really complain; this is the first loader that breaks down after 12 years of operating TD vehicles (7 of which were outside the specification ), and approximately 700,000 km.
Sorry for the lack of information, but I wanted to qualify my own statement, and in doing so, I always end up telling stories .



Best regards, Uli.