Small Diesel Engines - Natural Aspiration vs Turbo Charged?

[BoneStock]

Question #1 - Does turbo charging decrease the service life of the engine?

The "specific power" (HP per displacement volume, HP/Liter) is the generally accepted measure for an engine's life expectancy. The lower this figure, the longer the engine will last. A racing car may have 600HP/L and last a few 100 hours. A passenger car around 100HP/L and last 2,000 hours. Tractors have much lower specific power than cars, around 20HP/L. On one hand for a flatter torque curve, on the other hand for a longer service life of around 10,000 hours.

A turbo charger can be designed solely to improve fuel efficiency, in this case specific power remains the same and engine life is not affected.
Or it can be designed solely to maintain power at high altitude, in this case engine life is not affected either.
Or it can be designed to improve power, specific power is increased, and anything else remaining the same, engine life is decreased accordingly.

In practice, a turbo is designed to do a mix of everything above. Depending on which features are emphasized most, there will be more or less shortening of life expectancy. In the case of compact tractors, engine life is a non-issue, as the engine is designed to outlive the rest of the tractor several times over.



Question #2 - Which engine (of the same HP) gets better fuel efficiency?

The turbo Diesel engine will always be more efficient. How much depends on engine size.

On a very large engine (like a ship Diesel engine) a turbo can reduce fuel consumption by 70%. Such turbos are the size of a jet engine, and one single engine piston can have the diameter of a tractor wheel. On a diesel locomotive, savings may be 50%.

The smaller the diesel engine, the smaller the fuel savings. On a small car, savings may be in the order of 20%.



Question #3 - Are there any significant differences in engine maintenance requirements between the two types?

The turbo generally requires a higher specification engine oil.



Question #4 - Are there any significant differences on how well the DPF functions perform between the two types

Don't know the answer to that.


Thanks in Advance

[/QUOTE]

I agree with Cba,

Question 2; However, turbo chargers in theory and on paper are more efficient. In the real world they CAN be much less fuel efficient. All depends on the engine, rated rpms, and staying out of the boost. These turbo charged cars running around DRINK way more fuel then the rated mpg when you stay in the boost and zip and get around town. Tractor and diesels CAN also follow suite.

Question number 4 : no difference in my experience.

 

[Trillium Farm]

[/QUOTE] I agree with Cba,
Question 2; However, turbo chargers in theory and on paper are more efficient. In the real world they CAN be much less fuel efficient. All depends on the engine, rated rpms, and staying out of the boost. These turbo charged cars running around DRINK way more fuel then the rated mpg when you stay in the boost and zip and get around town. Tractor and diesels CAN also follow suite.
Question number 4 : no difference in my experience.[/QUOTE]

Absolutely true, on paper they are more efficient, but in real life they suck so much more gas than you can imagine. There are two reasons for having a turbo:
1) For the "Occasional" need of additional hp when a bigger engine doesn't make economic sense, for the buyer
2) To gain additional hp without having to go to the expense of having to design/manufacture a new bigger engine for the manufacturer.
Everything else is puffery.

 

[Agvg]

Hyper moderne gas engines would be useless without turboes.

New 1.3-litre TCe engine: a new-generation powerplant for the Renault range - media.renault.com

 

[adventure bob]

Remember that "efficiency" has nothing to do with fuel mileage. Efficiency is output per unit fuel consumed. There are way to many variables to use fuel mileage as a measure of efficiency.

 

[BoneStock]

Very true Trillium and adventure Bob :drink:

 

[truckdiagnostics]

My :2cents:
On a diesel tractor that would be running at a constant engine speed, I do believe a turbo would increase the engine efficiency. I do believe it would allow less valve over lap between intake and exhaust strokes, due to the turbo helping to improve engine exhaust scavenging.
Since a turbo increases intake air pressure an engine's compression ratio needs to be dropped. On a diesel this can make engines with a turbo a little more problematic for cold starting.
A turbo's bearing is actually a film of oil and that oil get real hot when it goes through the turbo, so most turbo charged diesel will have an oil cooler. They also produce a poop load of heat under the hood. So, I think a turbo charged engine requires more maintenance due to the heat it generates and the complexities that it adds.
I don't think you can have an engine with a DPF with out a turbo. You need the turbo to spool up to increase the air going into the CAT, so as to burn off the soot. I could be wrong but that is my understanding.
If I can get away with it I would take a naturally aspirated engine over turbo charged. I would avoid a computer controlled engine like the plague. I work with the stuff all day long. I love the computer controlled stuff, great money maker. A laptop is a lot easier to carry around than say pulling a set of heads. I wouldn't own one on my life. I lied we have one. It is an older IH where the software is free!

 

[Fallon]

You can have a DPF without a turbo. None of the Kubota economy L3s or my L4060 have a turbo & they have DPFs. Quite a few JDs & others are similar.

 

[truckdiagnostics]

You can have a DPF without a turbo. None of the Kubota economy L3s or my L4060 have a turbo & they have DPFs. Quite a few JDs & others are similar.

Ah, wonder how they are doing that? learned something new. On the truck engines when it goes into a parked regen, it will close the waste gate spool up the turbo and that CAT gets red hot. I have always thought the regen times(parked) that people were complaining about were rather long. I wonder if not having a turbo would make the regen on the DPF longer?

 

[Fallon]

Ah, wonder how they are doing that? learned something new. On the truck engines when it goes into a parked regen, it will close the waste gate spool up the turbo and that CAT gets red hot. I have always thought the regen times(parked) that people were complaining about were rather long. I wonder if not having a turbo would make the regen on the DPF longer?

They inject extra fuel that ends up getting burned in the DPF.

A catalytic converter causes unburned fuel to catalyze into exhaust products so hydrocarbons dont spew out the exhaust pipe. A DPF (Diesel Particulate Filter) is a filter. It's designed to catch the black soot that comes out of a diesel engine, not cause any chemical reaction like a catalytic converter. Like any filter, DPFs plug up as a byproduct of them doing their job. The regens get them really hot to burn off the accumulated soot. 2 entirely different processes. Diesels typically dont have catalytic converters because they would just plug up from the soot.

 

[Agvg]

This is my turbo, overhaul it with new bearings and seals, parts for 25$, it's very simple to fix, the bearings isn't super tight or that high precision, the important is end play.