Small Diesel Engines - Natural Aspiration vs Turbo Charged?

[Jchonline]

I don’t think I would pay extra just to get a TC all other things equal. If the TC gives you more HP and you need that for your application, then go for it. If it negates NA power losses at altitude and you need that power, go for it (as in my case). Turbos are so pervasive in vehicles and equipment these days I look at them like any other part. Sure they can wear out or break but it is no more likely than other parts for what we do with these machines. I have both Turbos in my truck and tractor, but I am new to it in tractors.

 

[Trillium Farm]

Always thought that superchargers where part of the block and there to give you additional torque at low rpms whereas turbos where there to give you power at high rpms, never heard of a clutch on them though.

 

[greggyy]

I thought super chargers were crankshaft driven and had an electric clutch. Not that I ever looked into it.

Not a fan of lifted monster trucks, rolling coal, but some kid was cruising through a gas station parking lot with such a truck and the turbo whine was quite impressive. Like a jet taxi-ing (don't have a clue how to spell that)

Yes, therefore the fiction that is Mad Max's vehicle

Mad max Blower... - YouTube

Now it of course is possible, but would be a pig of a think with a big supercharger if it was somehow disengaged, I could see a small one being possible with the EFI and systems around now, but why would you bother, a turbo is simple in comparison.

Anyway, it is a fiction, same with Turbo, you either have them or you do not, not turn them on or off, but a Turbo does not have to be on max boost all the time.

 

[greggyy]

Always thought that superchargers where part of the block and there to give you additional torque at low rpms whereas turbos where there to give you power at high rpms, never heard of a clutch on them though.

No, most of them bolt on, in the MM one, they bolt onto a manifold, well, they all bolt on to a manifold usually, and not usual to have a clutch, but that may exist in later model cars of which none have the weiand supercharger, there can always be an exception to the norm I suppose.

The reason it is a fiction, is that type of blower would be on a highly modded 8 usually & driven by serious belt from the crank.

Setups can be made to work at various rev ranges, the turbo benefits by being powered by waste and not taking lot of energy, in very high performance situations, the large type blower seems to be the go too, on the street and for most tractors etc, turbo is best suited for space reasons, economy, and noise....they are simple and reliable too and a good match IMO for injected vehicles.

PS I am no authority, but I know when Hollywood is pulling the wool over my eyes

 

[buickanddeere]

A good description can be found at wikipedia, search for supercharger.

Turbochargers are by far the most fuel efficient superchargers, because they use the otherwise lost waste heat from the exhaust.

All other superchargers consume up to 1/3 of the engine power to drive themselves. They still increase engine power output, but at the expense of fuel efficiency.

Examples:

engine with no supercharger produces 100HP, consumes 20kg fuel per hour, and delivers 100HP at the shaft

same engine with turbo produces 150HP, consumes 20kg fuel per hour, and delivers 150HP at the shaft (or produces 100HP, consumes 12kg/h, and delivers 100HP)

same engine with roots supercharger produces 300HP, consumes 60kg fuel per hour, and delivers 200HP at the shaft (100HP are consumed to drive the supercharger). Note that as this engine has to produce 3 times more power, it will not last very long. It will self destruct if not designed for the extra power and heat.

Maybe with an old 6-71 roots blower . Check the numbers of a Whipple with the bypass door . There is a reason why Ford GM and others sold them by the 100痴 of thousands from the factory .

 

[buickanddeere]

Diesel vs. Gas behave rather differently on the fuel efficiency (regardless of forced induction, which makes things worse). Diesel sprays just enough fuel into the combustion chamber to keep the engine spinning at the RPM set by the governor. A gas engine needs to keep up a fixed (stoichiometric)*fuel/air ratio.

So a diesel can run really lean when loafing at a fixed RPM then dump in as lot more fuel for more power at the same RPM. A gas machine on the other hand is a relatively fixed amount of power & fuel consumption at a given RPM.

Gas has the advantage of diesel a light and partial load . A diesel looses thermal efficiency by drawing unused air through the combustion chamber at part load . Take a look at the Nebraska tractors tests if you don稚 believe me . The lbs of fuel per HP at 25,50 and even 75% is lousy on a diesel .
Same reason why airflow is reduced in a commercial boiler when fuel flow is reduced .
Diesel efficiency occurs at max or near max power at the RPMs that peak torque occurs at . This is why spark ignition engines excell in light, some medium duty and stop/start applications .

 

[buickanddeere]

Turbo are free horse power

Nope . Have to allow for extra cooling . Extra power means extra fuel consumption.

 

[buickanddeere]

Yes, cover exhaust when transporting equipment. Turbos have oil lines going to bearings. Bearing are being oiled while the engine is running. If you spin the bearing for 2 hours with no oil, it is not good. Ask any large equipment dealer, Cat or Deere.

Turbos are one more thing on an engine to go bad. If you don't need it, don't add it. However, because it provides more air to the engine, it's use in today's engines is not only to provide more power but also for cleaner burn of the fuel. I have been told that a lot of smaller tractors are having the turbos installed to meet the EPA regulations.

Turbos are wrecked on transport due to foreign material injection such as small rocks .

 

[buickanddeere]

The older Toolcats used a Kubota engine and I don't know if they had heat issues. The newer Toolcats use a Doosan turbo engine that is Tier 4 compliant but does NOT use a particulant filter OR DEF fluid. YES!!! Tier IV without the bad things!

Bobcat Company released the Tier 4-compliant 5600 and 5610 Toolcat utility work machines that incorporate a non-DPF (diesel particulate filter) engine solution. These machines also feature a traction control system designed to provide operators with better mobility when ground conditions are conducive to traction loss, or the machines wheels encounter obstructions, such as rocks or debris. The Tier 4 Bobcat non-DPF solution was achieved by designing an ultra-low particulate combustion (ULPC) engine. The ULPC is accomplished through a specially designed engine combustion chamber that significantly reduces the amounts of particulate matter created during combustion. Therefore, Tier 4 emissions compliance can be achieved without using a DPF.

I heard that Bobcat was coming out with new tractors. Are they also not going to need DEF or regens? That would be a big selling point for me.

Depends on the HP range . Under 25HP diesels get away with a lot

 

[buickanddeere]

Always thought that superchargers where part of the block and there to give you additional torque at low rpms whereas turbos where there to give you power at high rpms, never heard of a clutch on them though.

No clutch but there has been bypass doors used for decades .