Direct Injected UAV Diesel Engine
11-09-2006 | 08:28 AM
#1
Direct Injected UAV Diesel Engine
http://www.cosworth.com/news_detail.php?id=66
http://www.gizmag.com/go/5917/
Cool. I wonder what the government pays for one of these.
http://www.gizmag.com/go/5917/
Cool. I wonder what the government pays for one of these.
11-09-2006 | 09:24 AM
#2
RE: Direct Injected UAV Diesel Engine
This is a remarkable achievement amd most likely the price will be too, Bottom line however is our current engines do well at a very reasonable prices the current fuel miixes when you figure economy of running them is not a major issue and as we know we have all given running and set up issues with compression and needle settings to help out the converts. I have my doubts with a lot of modlelers dealing with the possible complexity of this engine, and a hard landing would be curtains down, this does not in any way
degrade what they have done as I said remarkable. One a different note we have all seen the profusion on nice built up arfs that are great for converson to glow and small diesels
Even with the inroads of electric flight with its pros, cons, expense, it appears there is more intrest in diesel
Davis is cranking out more head conversions
I am still trying to upload his new head pix for the OS 10 anular ringed nice thumb screw compression adjustment
this is my next one martin
degrade what they have done as I said remarkable. One a different note we have all seen the profusion on nice built up arfs that are great for converson to glow and small diesels
Even with the inroads of electric flight with its pros, cons, expense, it appears there is more intrest in diesel
Davis is cranking out more head conversions
I am still trying to upload his new head pix for the OS 10 anular ringed nice thumb screw compression adjustment
this is my next one martin
01-10-2007 | 09:07 PM
#3
Junior Member
Joined: Nov 2004
Posts: 21
Likes: 0
Received 0 Likes
on
0 Posts
From: Tucson,
AZ
RE: Direct Injected UAV Diesel Engine
I have seen and held this engine. Having looked at the specifications I believe they still have qute a way to go. It is a beautiful engine, the machining is not as good as a DA and the weight is a bit more than what I hoped for before we recieved them. I see a couple of issues but I am not an engineer so what do I know. The head is held on by 4 bolts they apear to be about 3/16" and the RPM range is very limited. In order to effectivly use this engine a variable pitch prop will need to be developed.
They are headed in the right direction and as a first engine it is fine.
Steve
They are headed in the right direction and as a first engine it is fine.
Steve
01-10-2007 | 10:15 PM
#5
Junior Member
Joined: Nov 2004
Posts: 21
Likes: 0
Received 0 Likes
on
0 Posts
From: Tucson,
AZ
RE: Direct Injected UAV Diesel Engine
I miss spoke the bolts which secure the head also hold down the cylinder.
I do not remember the rpm range but it has a huge prop, 20"+ and the rpm spread is about 3,000 min to max.
Steve
I do not remember the rpm range but it has a huge prop, 20"+ and the rpm spread is about 3,000 min to max.
Steve
01-16-2007 | 11:08 AM
#10
RE: Direct Injected UAV Diesel Engine
The definition of a "diesel" is: direct injection, compression ignition. It doesn't matter if they call it a diesel or not. Sometimes they choose not to call them diesel not to imply that it will only operate on "diesel fuel". Direct injection compression ignition engines can be deisgned to burn anything from bunker oil to kerosene to waste vegetable oil. Many will burn a range of those fuels. There is no such thing as a manifold fuel injected or carburated diesel in the full size world. Those types of engine are called HCCI.
http://en.wikipedia.org/wiki/Diesel_engine
http://en.wikipedia.org/wiki/HCCI
http://en.wikipedia.org/wiki/Diesel_engine
http://en.wikipedia.org/wiki/HCCI
01-16-2007 | 01:45 PM
#11
RE: Direct Injected UAV Diesel Engine
The definition of a "diesel" is: direct injection, compression ignition
01-16-2007 | 04:49 PM
#12
RE: Direct Injected UAV Diesel Engine
No it must have near constant pressure. To do that fuel must be injected through most of its power stroke.
http://www.answers.com/topic/diesel-engine
01-16-2007 | 09:35 PM
#13
Senior Member
Joined: Jun 2006
Posts: 1,090
Likes: 0
Received 0 Likes
on
0 Posts
From: Santa Cruz,
CA
RE: Direct Injected UAV Diesel Engine
Yup - all direct injection or IDI compression ignition engines are diesels no matter whay they burn or what you call them..
I don't think there is any diesel that is constant pressure. I know people have tryed to do it.. There is no reason for that now days anyway. I'd say that all modern diesels ignite the fuel before top dead center and that causes a pressure spike that works well with the power stroke. The knock you hear in a diesel is a pressure spike.
There are plenty of IDI (inderect injection as in a pre chamber ) diesels out there as well.
Our little engines don't fit any catagory perfectly except internal combustion. But the compression ingnition part makes it fit the diesel catagory best in my opinoion.
I don't think there is any diesel that is constant pressure. I know people have tryed to do it.. There is no reason for that now days anyway. I'd say that all modern diesels ignite the fuel before top dead center and that causes a pressure spike that works well with the power stroke. The knock you hear in a diesel is a pressure spike.
There are plenty of IDI (inderect injection as in a pre chamber ) diesels out there as well.
Our little engines don't fit any catagory perfectly except internal combustion. But the compression ingnition part makes it fit the diesel catagory best in my opinoion.
01-17-2007 | 03:06 PM
#14
Senior Member
Joined: Dec 2006
Posts: 302
Likes: 0
Received 0 Likes
on
0 Posts
From: rome, ITALY
RE: Direct Injected UAV Diesel Engine
Treven,
very few engines work approximating Diesel cycle, since it can performed only partly without very particular arrangements. The Diesel cycle can work with a glow plug, a simple hot head previously heated with ...a blacksmith forge, or simply ignite on the rise of temperature caused by adiabatic compression.
NO commercial engine work following true Diesel cycle, so their efficiency is lower than the exceptional one of Diesel cycle. In practice they all differ from the original idea by approximating the isothermal combustion-expansion phase of the original cycle by means of tricks, more or less efficient and simple.
Model engines, apart from remarkable exceptions to be counted on the fingers of one hand, are the roughest approximation of diesel cycle. They are HCCI engines, (Homogeneus Charge Compression Ignition) The combustion-expansion is in practice left to nature, renouncing to the control of the injection of the fuel DURING the combustion, that is THE ONLY peculiar characteristic of the diesel cycle.
It is a common practice to name "diesel" every engine with compression ignition, as you understand this is only an approximation, but this can lead to considerable disguise when using too far the similitude. WHAT IS THE COMBUSTION OF A TRUE DIESEL WILL NEVER HAPPEN IN A MODEL "DIESEL", so the best thing is to forgot verbal similitudes.
very few engines work approximating Diesel cycle, since it can performed only partly without very particular arrangements. The Diesel cycle can work with a glow plug, a simple hot head previously heated with ...a blacksmith forge, or simply ignite on the rise of temperature caused by adiabatic compression.
NO commercial engine work following true Diesel cycle, so their efficiency is lower than the exceptional one of Diesel cycle. In practice they all differ from the original idea by approximating the isothermal combustion-expansion phase of the original cycle by means of tricks, more or less efficient and simple.
Model engines, apart from remarkable exceptions to be counted on the fingers of one hand, are the roughest approximation of diesel cycle. They are HCCI engines, (Homogeneus Charge Compression Ignition) The combustion-expansion is in practice left to nature, renouncing to the control of the injection of the fuel DURING the combustion, that is THE ONLY peculiar characteristic of the diesel cycle.
It is a common practice to name "diesel" every engine with compression ignition, as you understand this is only an approximation, but this can lead to considerable disguise when using too far the similitude. WHAT IS THE COMBUSTION OF A TRUE DIESEL WILL NEVER HAPPEN IN A MODEL "DIESEL", so the best thing is to forgot verbal similitudes.
01-17-2007 | 03:17 PM
#15
RE: Direct Injected UAV Diesel Engine
I don't think there is any diesel that is constant pressure.
01-17-2007 | 03:24 PM
#16
RE: Direct Injected UAV Diesel Engine
ORIGINAL: merugo
Treven,
very few engines work approximating Diesel cycle, since it can performed only partly without very particular arrangements. The Diesel cycle can work with a glow plug, a simple hot head previously heated with ...a blacksmith forge, or simply ignite on the rise of temperature caused by adiabatic compression.
NO commercial engine work following true Diesel cycle, so their efficiency is lower than the exceptional one of Diesel cycle. In practice they all differ from the original idea by approximating the isothermal combustion-expansion phase of the original cycle by means of tricks, more or less efficient and simple.
Model engines, apart from remarkable exceptions to be counted on the fingers of one hand, are the roughest approximation of diesel cycle. They are HCCI engines, (Homogeneus Charge Compression Ignition) The combustion-expansion is in practice left to nature, renouncing to the control of the injection of the fuel DURING the combustion, that is THE ONLY peculiar characteristic of the diesel cycle.
It is a common practice to name "diesel" every engine with compression ignition, as you understand this is only an approximation, but this can lead to considerable disguise when using too far the similitude. WHAT IS THE COMBUSTION OF A TRUE DIESEL WILL NEVER HAPPEN IN A MODEL "DIESEL", so the best thing is to forgot verbal similitudes.
Treven,
very few engines work approximating Diesel cycle, since it can performed only partly without very particular arrangements. The Diesel cycle can work with a glow plug, a simple hot head previously heated with ...a blacksmith forge, or simply ignite on the rise of temperature caused by adiabatic compression.
NO commercial engine work following true Diesel cycle, so their efficiency is lower than the exceptional one of Diesel cycle. In practice they all differ from the original idea by approximating the isothermal combustion-expansion phase of the original cycle by means of tricks, more or less efficient and simple.
Model engines, apart from remarkable exceptions to be counted on the fingers of one hand, are the roughest approximation of diesel cycle. They are HCCI engines, (Homogeneus Charge Compression Ignition) The combustion-expansion is in practice left to nature, renouncing to the control of the injection of the fuel DURING the combustion, that is THE ONLY peculiar characteristic of the diesel cycle.
It is a common practice to name "diesel" every engine with compression ignition, as you understand this is only an approximation, but this can lead to considerable disguise when using too far the similitude. WHAT IS THE COMBUSTION OF A TRUE DIESEL WILL NEVER HAPPEN IN A MODEL "DIESEL", so the best thing is to forgot verbal similitudes.
Model Diesel engines are actually Otto cycle engines without the spark. The thermodynamics is the same near constant volume. They are constant volume only because the fuel burns extremely quick. While a Diesel engine is not truely 100% constant pressure, they are reasonably close, with the pressure staying fairly constant and winding down near the end. The injection is also usually delayed a bit, but most are near constant volume while the injector is injecting fuel. However modern engines will change the timing of the injector instead of changing the rate of fuel injected, especially near the end of the power stroke.
01-17-2007 | 04:28 PM
#17
RE: Direct Injected UAV Diesel Engine
If it's not a diesel what is it?
We have:
Spark Igntion: carburated, manifold injected, or direct injected, but ignition source is always spark.
Compression Igntion: direct injection or indirect injection(prechamber). Ignition is due to injecting fuel into compressed air hot enough to ignite it. Timing is dependent on injection.
HCCI(homogenous combustion compression ignition): Carburated, manifold injected, direct injected. Ignition is due to compression of fuel/air mixture and timing is dependent on lambda, compression ratio, and a variety of other factors.
There are also mixed mode HCCI engines. that switch between HCCI and spark ignition or HCCI and direct injection compression ignition.
Model engines (glow and diesel) most definitely fall into the HCCI category.
http://en.wikipedia.org/wiki/HCCI
We have:
Spark Igntion: carburated, manifold injected, or direct injected, but ignition source is always spark.
Compression Igntion: direct injection or indirect injection(prechamber). Ignition is due to injecting fuel into compressed air hot enough to ignite it. Timing is dependent on injection.
HCCI(homogenous combustion compression ignition): Carburated, manifold injected, direct injected. Ignition is due to compression of fuel/air mixture and timing is dependent on lambda, compression ratio, and a variety of other factors.
There are also mixed mode HCCI engines. that switch between HCCI and spark ignition or HCCI and direct injection compression ignition.
Model engines (glow and diesel) most definitely fall into the HCCI category.
http://en.wikipedia.org/wiki/HCCI
01-17-2007 | 07:52 PM
#20
Junior Member
Joined: Nov 2004
Posts: 21
Likes: 0
Received 0 Likes
on
0 Posts
From: Tucson,
AZ
RE: Direct Injected UAV Diesel Engine
This is a compression ignition diesel. here are some of the specs for the engine.
Weight 3.8 Kg
HP 3.5 HP
RPM range 3500 RPM Min / 5100RPM Max.
Prop specifications 27-10
Max RPM 5000 Max.
This engine is being evaluated in Tazmania with results to follow.
Steve
Weight 3.8 Kg
HP 3.5 HP
RPM range 3500 RPM Min / 5100RPM Max.
Prop specifications 27-10
Max RPM 5000 Max.
This engine is being evaluated in Tazmania with results to follow.
Steve
