Reducing Diesel Engine Output
Reducing Diesel Engine Output
(OP)
I have a task that only needs around half of my single-cylinder diesel engine's rated capacity.
The question is, what is the simplest way to run my engine at partial load without sacrificing efficiency? The obvious ones are reducing displacement through a sleeve, or possibly an EFI conversion. But that takes a lot of work.
I have read somewhere about insulating the whole cylinder block to minimize heat loss when running the engine at low rpm. Any thoughts on this?
btw, for the sake of discussion let's not consider getting a smaller engine an option. Im already using a 2.5kw diesel engine. I don't know if there's a smaller one available in the market today. :)
TIA. :)
The question is, what is the simplest way to run my engine at partial load without sacrificing efficiency? The obvious ones are reducing displacement through a sleeve, or possibly an EFI conversion. But that takes a lot of work.
I have read somewhere about insulating the whole cylinder block to minimize heat loss when running the engine at low rpm. Any thoughts on this?
btw, for the sake of discussion let's not consider getting a smaller engine an option. Im already using a 2.5kw diesel engine. I don't know if there's a smaller one available in the market today. :)
TIA. :)





RE: Reducing Diesel Engine Output
Not much point in insulating the outside of a water jacket
Regards
Pat
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RE: Reducing Diesel Engine Output
RE: Reducing Diesel Engine Output
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
http://eng-tips.com/market.cfm
for site rules
RE: Reducing Diesel Engine Output
How bad is the fuel use at the intended load?
RE: Reducing Diesel Engine Output
Trimming the cooling fan so that it is pumping no more air than necessary to keep the cylinder head at an acceptable temperature, to reduce fan losses, might be worth doing.
RE: Reducing Diesel Engine Output
Diesel engines have the ability to retain their efficiency at low loading. As already mentioned, about the only thing you can do is reduce spurious losses. If the generator is belted you can change pulleys to reduce engine RPM.
Or use an inverter generator. They allow engine RPM to be independent of line frequency. They are set up to run the engine just fast enough to develop the power needed. Inverter generators are becoming quite popular since they reduce noise and significantly reduce fuel consumption at low load.
RE: Reducing Diesel Engine Output
http://iee
This curve for a generic diesel suggests at some rpm the BSFC is less than 10% worse at half load. http://u
RE: Reducing Diesel Engine Output
Yes less than 10% worse at half load same rpm.
Best consumption at HALF POWER is 216 at just under 1700 rpm - less than 5% worse than peak BSFC.
Engineering is the art of creating things you need, from things you can get.
RE: Reducing Diesel Engine Output
I forgot to mention that I need to run it also at the lowest RPM possible. How can I demand, say, 1.5kW at a speed of less than 2000 without the engine shutting down?
RE: Reducing Diesel Engine Output
If it gets enough air at that speed to develop the power, or w/o lugging badly, the governor in the injection pump should handle it.
If you have problems w/ smoothness, you could add weight to the flywheel so that you have enough rotational energy to make it around twice without appreciable drop in RPM.
Really, consider the cost of modifications compared to whatever you'll be saving by running it as is.
RE: Reducing Diesel Engine Output
http://www
JMW
www.ViscoAnalyser.com
RE: Reducing Diesel Engine Output
RE: Reducing Diesel Engine Output
A properly designed cylinder / piston / cylinder head have an insulating blanket of air that blocks a lot of the heat loss.
If the injectors are good, they are suppose to keep fuel away from the cylinder walls, where they both cool and wash down the walls of lubricant.
The best gain in efficiency may be lower RPM, as pumping losses (big) rises exponentially with speed.
Can you gear it to something between 1,200 to 1,500 rpm running with your load?
RE: Reducing Diesel Engine Output
RE: Reducing Diesel Engine Output
1) The mechanical efficiency is increased by the power not used to drive the fan so hard.
2) The thermal efficiency is increased by reduced cooling of the gas that is driving the piston down.
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
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for site rules
RE: Reducing Diesel Engine Output
The issue of power lost via Fan can be addressed with a electrically operated (or thermal / mechanical viscous coupling) fan.
I can see the gain from the electrical at moderate cost.. but is it really worth it?
RE: Reducing Diesel Engine Output
You run it so it cools adequately on the hottest day. If it has a thermostat you use that to stop over cooling on cold days.
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
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RE: Reducing Diesel Engine Output
http://www.youtube.com/watch?v=fZ4ORUZ41K0
I've heard one running in a barge where it would fire a couple of times, run on under the influence of its flywheel fire again, quite again.... more like this one working hard....
or this 9hp which goes ffrom low load to load to low load again:
ht
JMW
www.ViscoAnalyser.com