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Small Diesel Engines - Natural Aspiration vs Turbo Charged?
- Thread starter welyell
- Start date
- Views: 37128
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Who Replied?finn1
Platinum Member
- Joined
- May 10, 2009
- Messages
- 899
- Location
- Upper Michigan, Marana Az.
- Tractor
- Kioti CK4010 hst, Cab, Deere 26G excavator, K1500 w/ Boss 7’6” plow, F450 dump W/ Boss 10’ straight blade Super Duty plow, F250 reg cab, F350 cc drw, Case TR310 CTL
First of all, my tractor is na only because a turbo version wasn稚 offered in that frame size machine, and storage considerations limited the size of tractor.
My mini ex is na, only because of budget and machine size storage constraints. Engine configuration was irrelevant in this case.
All other things being equal (which they rarely are), a na engine will offer better fuel economy in the part load region of the speed-load map because the turbo increases pumping losses at light loads, where you don稚 need more air for combustion. We once had a product rationalization program to replace a large displacement na engine, widely loved by the customers, with a smaller displacement but turbocharged engine of the same family. The development engineers could never match the bsfc map of the na engine because of the turbo induced losses.
Today, it could probably be done with the addition of newer technology like common rail, intercooling, and electronic turbo controls, but that all comes at a cost, and, yes, tractors are cost sensitive.
Fuel consumption (and smoke) hooks on an na engine as power is increased and, at higher power levels, the fuel economy, on a Brake specific basis, is better with the turbo. The turbo engine power range can obviously be extended over the na, and intercoolers, compounding, etc go even further.
These small utility tractors rarely operate at high output though, so the na would give better economy, again, all other things being equal. Turbo engines have far better potential for emission control.
The turbo does allow a power curve with higher torque rise, which is, in my experience more important than absolute power at rated speed. We used to shoot for a minimum torque rise of 15% on farm tractor applications when setting power curves. The relatively high torque rise keeps the engine from bogging as the implement or attachment engages the load.
Lack of torque rise is a point of dissatisfaction I personally have with my Kioti CK4010 SE.
A well designed turbo engine will have the same design life, durability qualification, and warranty targets as an na engine, and will have superior altitude capability.
That said, there痴 no getting around the fact that there are more moving parts and potential leak paths with a turbo. That痴 not an issue on a well designed engine though.
Sort of like arguing that manual windows are superior to roll up windows. That argument logic goes to stationary windows, or better yet, no windows are better yet....
My mini ex is na, only because of budget and machine size storage constraints. Engine configuration was irrelevant in this case.
All other things being equal (which they rarely are), a na engine will offer better fuel economy in the part load region of the speed-load map because the turbo increases pumping losses at light loads, where you don稚 need more air for combustion. We once had a product rationalization program to replace a large displacement na engine, widely loved by the customers, with a smaller displacement but turbocharged engine of the same family. The development engineers could never match the bsfc map of the na engine because of the turbo induced losses.
Today, it could probably be done with the addition of newer technology like common rail, intercooling, and electronic turbo controls, but that all comes at a cost, and, yes, tractors are cost sensitive.
Fuel consumption (and smoke) hooks on an na engine as power is increased and, at higher power levels, the fuel economy, on a Brake specific basis, is better with the turbo. The turbo engine power range can obviously be extended over the na, and intercoolers, compounding, etc go even further.
These small utility tractors rarely operate at high output though, so the na would give better economy, again, all other things being equal. Turbo engines have far better potential for emission control.
The turbo does allow a power curve with higher torque rise, which is, in my experience more important than absolute power at rated speed. We used to shoot for a minimum torque rise of 15% on farm tractor applications when setting power curves. The relatively high torque rise keeps the engine from bogging as the implement or attachment engages the load.
Lack of torque rise is a point of dissatisfaction I personally have with my Kioti CK4010 SE.
A well designed turbo engine will have the same design life, durability qualification, and warranty targets as an na engine, and will have superior altitude capability.
That said, there痴 no getting around the fact that there are more moving parts and potential leak paths with a turbo. That痴 not an issue on a well designed engine though.
Sort of like arguing that manual windows are superior to roll up windows. That argument logic goes to stationary windows, or better yet, no windows are better yet....
buickanddeere
Super Member
250 cubic inches of turbo diesel isn’t going to pull much different than 400cu inches of natural aspirated . In fact when lugged to the last breath the turbo diesel will stall because the turbo has slowed down . while the natural aspirated is still running .Yes, but a engine with a turbo can pull more at lower RPM so in real life you have less fuel consumption if you are have the same load.
buickanddeere
Super Member
An electrically injected diesel with a waste gate turbo can have the torque rise to impressive amounts when lugged . Then again the top end power will be limited to make the lugging power appear more impressive.
All out max torque from idle to redline would look much different .
All out max torque from idle to redline would look much different .
Agvg
Elite Member
Low weight pr kw is also a factor, the nice Mercedes V10 on 19 liters I drove had one thing the smaller turbo engines didn't, very high torque below 1000 rpm, but with its 360hp it didn't get much speed for all that diesel it wanted....
DK35vince
Super Member
???Turbos are wrecked on transport due to foreign material injection such as small rocks .
Never heard of such a thing.
How are small rocks in there, unless you took the air filter out.
Fallon
Super Member
Stuff comming in the exhaust pipe rather than the intake.???
Never heard of such a thing.
How are small rocks in there, unless you took the air filter out.
I'm pretty suspicious of the whole issue with the turbo spinning enough with no load being an actual issue. But not enough that I'd risk not stuffing a plug if some sort in the exhaust pipe when towing if I had a turbo on my machine.
DK35vince
Super Member
Still don't get it.Stuff comming in the exhaust pipe rather than the intake
Wouldn't these stones still have to get down the exhaust pipe, through the exhaust valves, into the cylinder, out the intake valves, into the intake to ever reach the turbo?
At work we probably have 2 dozen pieces of equipment that are turbo diesel, ( trucks, chippers, pavers, skid steers, loaders, rollers, Etc. Etc)
Very, rare to have a turbo problem.
Last edited:
Fallon
Super Member
There are 2 halves to a turbo. 1 on the intake & 1 on the exhaust. So you can damage the blades, seals & housing on either side. The exhaust side of the turbo is just upstream of the tip of the exhaust pipe. There may or may not be emissions stuff after the turbo. I'm not clear if a DPF would go before or after the turbo on a modern machine.Still don't get it.
Wouldn't these stones have to get down the exhaust pipe, through the exhaust valves, into the cylinder, out the intake valves, into the intake to ever reach the turbo?
DK35vince
Super Member
Wouldn't a stone still have to make it through the exhaust pipes and muffler to get to the exhaust side turbo.There are 2 halves to a turbo. 1 on the intake & 1 on the exhaust. So you can damage the blades, seals & housing on either side. The exhaust side of the turbo is just upstream of the tip of the exhaust pipe. There may or may not be emissions stuff after the turbo. I'm not clear if a DPF would go before or after the turbo on a modern machine.
In all the decades I've been around turbo diesels I have never heard of a turbo being damaged by foreign material/small rocks getting in during transport.
I have heard its possible for wind to damage a turbo during transport.
But so far in all the years we've been moving turbo equipment to and from the job sites, we have never had it happen
