74kW Engine: PD vs. Euro3/Euro4 Differences

Hello everyone,

"Does anyone know the 'smaller' 74 kW (101 hp) PD engines well enough to tell me in detail about the differences between the engine types that meet the Euro 3 and Euro 4 standards?"

Was war der Zweck der zusätzlichen Ausrüstung mit einer Drosselklappe in der Euro4-Version, beispielsweise zur Erreichung höherer Abgasrückführungsraten (AGR), oder wo liegen die wesentlichen Unterschiede?

Thank you for the expert information.

Regards,
Alex.

donalexo wrote:

Hello everyone, "Does anyone know the 'smaller' 74 kW (101 hp) common rail diesel engines well enough to tell me in detail about the differences between the engine variants that meet Euro 3 and Euro 4 standards?"

- MSG (OBD2 compatible)
- PDEs (Version 1.1)
- Controlled water cooling of the EGR system.
- Electric Dosing System (adjustable application rate).
...

These are some of the "major" pieces.

Hello Bertil, thank you very much for the information!

That immediately makes me think of a few "follow-up questions" on that topic.

"How susceptible are systems with an EGR system controlled by three degrees of freedom (where the opening of the EGR valve affects the EGR flow rate, the VTG affects exhaust back pressure, and the throttle valve affects the intake air flow) compared to Euro3 systems without a throttle valve, based on practical experience?"
Does the throttle valve actuator operate electromechanically or pneumatically?

Does the increased rate of exhaust gas recirculation (EGR) noticeably increase the amount of deposits forming in the intake manifold?

Does a regulated EGR cooling circuit mean that there is a separate thermostat located there that regulates the coolant temperature (a low-temperature circuit for the EGR cooler)?


Thank you.

Best regards, Alex.

donalexo wrote:

... "How susceptible are systems with an EGR system controlled by three degrees of freedom (where the opening of the EGR valve affects the EGR flow rate, the VTG affects exhaust back pressure, and the throttle valve affects the intake air flow) compared to Euro3 systems without a throttle valve, based on practical experience?"

Discreetly.

Quote:

Does the throttle valve actuator operate electromechanically or pneumatically?

Electromechanical.

Quote:

Does the increased rate of exhaust gas recirculation (EGR) noticeably increase the amount of deposits forming in the intake manifold?

No... actually, due to the overall lower soot content of the EU4 engine in the exhaust gases, it produces even less.

Quote:

Does a regulated EGR cooling circuit mean that there is a separate thermostat located there that regulates the coolant temperature (a low-temperature circuit for the EGR cooler)?

It is regulated by the MSG.
For this purpose, the modified pneumatic system from the AK (originally from the ATD) is used in the AXR. This is permissible because the DK does not need to be controlled via this system.

Hello Bertil!

Thank you for your insider knowledge.
What's the current mileage on your AXR engine, and what kind of driving conditions have you been using it in?

Your assessment that the highly complex AGR system behaves inconspicuously in the Euro4 engine makes me optimistic.

Currently, I'm looking for a "new" vehicle on the used car market. I find the "smaller" PD to be very enjoyable to drive because it's quite agile, especially at low RPMs. When replacing a vehicle, of course, one strives to acquire a car with a modern emission standard, so that you can still drive in major cities in the future.
During my search, I am also considering vehicles with higher mileage (over 150,000 km), which is why I wanted to investigate the topics of "robustness of the AGR system" and "carbon buildup in the intake manifold" further.

Is it correct to assume that all previous statements also apply directly to the 77 kW PD version?

Thank you for the additional information and comments.

Regards,
Alex.

donalexo wrote:

... What's the current mileage on your AXR engine, and what kind of driving conditions has it been subjected to?

156,000 km ... Daily commute of 2 * 48 km on rural roads (very hilly and winding).

Quote:

Your assessment that the highly complex AGR system behaves inconspicuously in the Euro4 engine makes me optimistic.

I wouldn't call that highly complex.

Quote:

I find the "small" PD to be very enjoyable to drive because it's particularly agile at low RPMs.

I can confirm that. Especially with the "WoWa" feature, it's always fun to use this thing again and again.

Quote:

When purchasing a replacement vehicle, one naturally strives to acquire a car that meets current emission standards, so that it can still be driven in major cities in the future.

I did the same thing 6.5 years ago, and the most current emission standard was a deciding factor against a competitor that had a DPF (Diesel Particulate Filter). Therefore, the AXR engine didn't disappoint me in this regard either.
I can't attribute the annoying clutch problems to the engine itself. However, they are rarely observed in newer models (from the model year 2003 onwards).

Quote:

During my search, I am also considering vehicles with higher mileage (over 150,000 km), which is why I wanted to investigate the topics of "robustness of the AGR system" and "carbon buildup in the intake manifold" further.

Vehicles with over 150,000 kilometers (approximately 93,000 miles) might benefit from a new set of particulate diesel emission (PDE) injectors. These injectors are wear items, just like those in older vehicles. This financial risk should be considered when making a purchase and factored in from the beginning.

Quote:

Is it correct to assume that all previous statements also apply directly to the 77 kW PD version?

My brother has the 77kW "Bruder" engine from an AXR (which should actually be a BKC) in his G5, and even after 85,000 km, the intake system looks very clean. However, this car is driven extensively in city traffic.
These "bread and butter" cars are, in my opinion, really quite good. That's why they are often very expensive on the used car market.

Good luck with your search.

Hello everyone,

'Does anyone know the 'smaller' 74 kW (101 hp) common rail diesel engines well enough to tell me in detail about the differences between the engine variants that meet Euro 3 and Euro 4 standards?'


- MSG (OBD2 compatible)
- PDEs (Version 1.1)
- Controlled water cooling of the EGR system.
- Electric Dosing System (adjustable application rate).
...

These are some of the 'major' items.

Starting in February 2001, all of this was installed. Except, presumably, the MSG (Message System).
The classification was Euro3/D4. Mine is a similar model.

I don't know exactly when the switch to Euro4 standards was made.

powermac wrote:

... Starting in February 2001, all of this was installed. Except, presumably, the MSG (Message System).

Sure.
With the introduction of D4/EU3, a modified MSG (Motor Steuergerät - Engine Control Unit) was already implemented. Otherwise, it would not have been possible to control the DK (Kühlmittelpumpe - Coolant Pump) and the regulation for water cooling at the AGR (Abgasrückführung - Exhaust Gas Recirculation).

Quote:

The classification was Euro3/D4. Mine is one of those models.

Mine too.

Quote:

I don't know exactly when the switch to Euro4 was made.

Regarding the MJ03.
There were further changes implemented there. I can't/won't say more about it.

Quote:

Regarding the MJ03. There were other changes implemented there. I can't/won't say more about it.

Too bad!

What I'm also very interested in knowing is: What is the average fuel consumption of your AXR vehicle over the long term?

Since my driving profile is very similar to Bertil's (approximately 2 trips of 45 km per day, also a rural route with hills and curves), I am very curious to see the results.

With my VP-TDI engine, I usually get a fuel consumption of between 4.7 and 4.9 liters per 100 kilometers.

Regards,
Alex.

Well, I can only tell you about my experience with the ASZ.

"I also drive in hilly areas, with fewer curves. I mostly use the 6th gear and travel about 30 kilometers each way. Under normal weather conditions (mostly downhill), I can achieve a fuel consumption of 4.2 to 4.6 liters per 100 kilometers. On the return trip (which is more uphill), I get between 4.6 and 5.0 liters per 100 kilometers. My speed is usually between 80 and 110 km/h, never faster... because if I go faster, the fuel consumption easily exceeds 6.0 liters per 100 kilometers."

As Bertil already mentioned, you need to drive PD TDI engines differently than VP engines. Additionally, the models from the Golf IV onwards have become quite heavy. Unfortunately.

Hello Matthias!

Quote:

Wie Bertil schon sagt, PD TDI muss man anders fahren als VP Motoren. Zusätzlich sind die Modelle ab Golf iv recht schwer geworden. Unfortunately.

And what is the "secret recipe" for efficiently managing PDs (presumably referring to project deliverables or similar)?

Regards,
Alex.

donalexo wrote:

Quote: Wie Bertil schon sagt, PD TDI muss man anders fahren als VP Motoren. Zusätzlich sind die Modelle ab Golf iv recht schwer geworden. Unfortunately. And what is the "secret recipe" for efficiently managing PDs (presumably referring to project deliverables or similar)?

In short:
To increase speed, upgrade the components.

The VP needs to be driven at a slightly higher RPM. With the PD, you need to utilize the readily available torque and absolutely avoid high RPMs.
Even with a "forced acceleration," I don't rev my engine above 3000 RPM (it doesn't really achieve anything with the AXR engine anyway).
Accelerate quickly to the desired speed and then let the engine (as much as possible) idle. Especially the AXR engine tends to run more like a gasoline engine in "coasting" mode. Those who take advantage of this can save a lot of diesel fuel.

However, you will consume slightly more fuel with the PD system.

In modern direct injection (DI) engines, the fuel consumption patterns tend to be more similar to those of gasoline engines. While with older designs, it was sometimes possible to drive without excessive fuel consumption, modern DI engines can quickly become "fuel guzzlers."

EDIT: My consumption is between 5.3 and 5.5 (slightly higher in winter, up to 6.0); with a trailer attached, it's between 8 and 12.5!

Hello everyone,

I've also noticed another unpleasant behavior in the newer engine generation. It concerns the "castration" of the engine torque in first gear for the newer PD models. I find it very noticeable and unpleasant that the transmission allows less torque to reach the wheels in first gear, even with the same accelerator pedal position.

Can someone classify when this "nonsense" started to gain traction?

Regards,
Alex.

donalexo wrote:

... Can someone classify when this "nonsense" started to gain traction?

Welcome to the world of EU4 engines...
I've also encountered that with some EU3 engines.

"Exhaust castration" can bring about some unpleasant side effects. This is already noticeable in some gasoline engines.

It's about the 'castration' of the engine torque in first gear on the newer PD models. I find it very noticeable and unpleasant that the MSG (presumably a transmission or control system) allows less torque to reach the wheels in first gear, even with the same accelerator pedal position.

Welcome to the world of EU4 engines...

Hello,

Ah, that explains the many driver preference fields in the EDC16 software!

Then this is not necessarily the case for every EURO4 application.
My BLS has many driver wish lists, but they are all completely identical.

Best regards, Jochen.

Hello everyone!

Another question that relates to these "smaller" PD engines concerns the durability/reliability of the turbochargers used in them. How common are problems with sticking variable geometry turbines (VTG) or even more serious turbocharger failures in these engines?
Are there any unusual characteristics related to the turbochargers in these engines?

Thank you in advance .

Regards,
Alex.