Alyn Foundry
Active Member
Aren’t you confusing Nicolaus August Otto with Rudolph Diesel?
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What is a Diesel Engine ?
- Thread starter GreenTwin
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A simple truth. Do you want the horrible smell of diesel fuel in your workshop.
If I need to refuel a diesel car I make sure gloves are used. That oily crap lasts forever if you get it say on the steering wheel.
If I need to refuel a diesel car I make sure gloves are used. That oily crap lasts forever if you get it say on the steering wheel.
I seems the diesel engine has gone through more evolutionary changes than the gasoline engine, so it would seem.
I have much reading to do.
Sidenote:
I think I have a copy of the book Internal Fire, written by Lyle Cummins, and I seem to recall the front page is signed by Lyle.
My dad use to know a guy in the publishing business (Tom Lindsay), so perhaps that is where it came from.
I am going to look for that book, and see if I am recalling that correctly.
.
I have much reading to do.
Sidenote:
I think I have a copy of the book Internal Fire, written by Lyle Cummins, and I seem to recall the front page is signed by Lyle.
My dad use to know a guy in the publishing business (Tom Lindsay), so perhaps that is where it came from.
I am going to look for that book, and see if I am recalling that correctly.
.
Alyn Foundry
Active Member
I personally think that both evolutionary processes are on a par with each other.
You might like to consider reading up on George B Brayton? He’s been an almost forgotten pioneer in the area of internal combustion. Accredited with the invention of the liquid fuel injector and his Cycle is now in extensive use around the world.
I have been very slowly building a replica of one of his engInes for over 20 years now. Hopefully I will get to finish it in the next couple of years.
Cheers Graham.
Around here, an 18-wheel truck is called a semi, and it invariably is powered by a diesel, so ...
That is an awesowme engine for sure, especially that flywheel !
The frame is quite a piece of work too.
And nice beam !
I prefer grand scale models (small engines really), since it is easier for me to see and machine the parts.
.
Green Twin. I understood that any small representation of the full-sized object is a model, whether acurate scale or simply a look-alike, to demonstrate a principle of operation.
If used for its size and performance to power something by conversion of energy in one form to another, then it is certainly an engine. Grammatically, yours sounds like a "model engine" as in model of an engine. But alternatively, e.g. many model aircraft are powered by full- sized - all-be-it small - engines that are not representative of other engines that would have powered these full- sized aircraft. But we call these "model engines" as engines that power models.....
The has is therefore all encompassing. Do not be shy to call yours a model engine.
There is also another similar grammatical use of model, as in the full sized person who demonstrates clothes.... and model is often used to suggest this is the t quality target that we may aspire to.... I think your models probably deserve this use of "model" as well. The excellent workmanship and finish set a standard we aspire to.
K2
If used for its size and performance to power something by conversion of energy in one form to another, then it is certainly an engine. Grammatically, yours sounds like a "model engine" as in model of an engine. But alternatively, e.g. many model aircraft are powered by full- sized - all-be-it small - engines that are not representative of other engines that would have powered these full- sized aircraft. But we call these "model engines" as engines that power models.....
The has is therefore all encompassing. Do not be shy to call yours a model engine.
There is also another similar grammatical use of model, as in the full sized person who demonstrates clothes.... and model is often used to suggest this is the t quality target that we may aspire to.... I think your models probably deserve this use of "model" as well. The excellent workmanship and finish set a standard we aspire to.
K2
Being fair, we probably rarely consider how important Diesel was in developing his thermodynamic engine cycle. But his importance is really appreciated by the way we use his name to describe, engines, fuels, and even 18-wheelers as "Diesel".
Perhaps as important as N. Tesla, who's AC mains electricity powers our homes, factories etc. Instead of calling it AC power maybe it should be referred to as Tesla Power? But Eddison and history didn't choose that name. Just a car maker.... does he use Tesla Power as variable frequency AC to drive the motors?
K2
Perhaps as important as N. Tesla, who's AC mains electricity powers our homes, factories etc. Instead of calling it AC power maybe it should be referred to as Tesla Power? But Eddison and history didn't choose that name. Just a car maker.... does he use Tesla Power as variable frequency AC to drive the motors?
K2
Roger B
Well-Known Member
To me the key difference in Diesels work was that he started with the theory behind the design and then went on to try and realise it in practice.
The earlier developers of internal combustion engines developed them as they went along, investigating various dead ends on the way.
Carnot’s ideal thermodynamic cycle 1824 showed the benefit of compression in increasing efficiency but this was rarely implemented in the early days, non-compression engines being the norm. The problems of early fuels and materials were obvious limiting factors.
Hot tube ignition was not very precise and for small engines more fuel could be used heating the tube than running the engine.
Hot bulb engines were an interesting intermediate stage. Akroyd Stuart developed it to keep the fuel and the air separate to avoid pre ignition and used the hot bulb to vaporise the fuel rather than some form of external carburetor. The relative simplicity, acceptance of a very wide range of fuels and low pressures meant they were popular for many years. They were surpassed by the higher efficiencies and instant availability of diesel engines.
Interestingly some of the ideas have almost come full circle. Diesel’s original design concept was to inject the fuel over a period of time to control the maximum cylinder pressure. This was possible with the slow speed engines of the time and is still the case on big ship diesel engines. As engine speeds increased the cycle moved more towards a constant volume combustion similar to Otto’s cycle used on spark ignition engines. Modern turbo charged small diesels are now injecting the fuel in several steps to control the maximum cylinder pressure.
The earlier developers of internal combustion engines developed them as they went along, investigating various dead ends on the way.
Carnot’s ideal thermodynamic cycle 1824 showed the benefit of compression in increasing efficiency but this was rarely implemented in the early days, non-compression engines being the norm. The problems of early fuels and materials were obvious limiting factors.
Hot tube ignition was not very precise and for small engines more fuel could be used heating the tube than running the engine.
Hot bulb engines were an interesting intermediate stage. Akroyd Stuart developed it to keep the fuel and the air separate to avoid pre ignition and used the hot bulb to vaporise the fuel rather than some form of external carburetor. The relative simplicity, acceptance of a very wide range of fuels and low pressures meant they were popular for many years. They were surpassed by the higher efficiencies and instant availability of diesel engines.
Interestingly some of the ideas have almost come full circle. Diesel’s original design concept was to inject the fuel over a period of time to control the maximum cylinder pressure. This was possible with the slow speed engines of the time and is still the case on big ship diesel engines. As engine speeds increased the cycle moved more towards a constant volume combustion similar to Otto’s cycle used on spark ignition engines. Modern turbo charged small diesels are now injecting the fuel in several steps to control the maximum cylinder pressure.
This might interest you:
Apparently they use both types of motors.
Electronic starters for AC motors have improved greatly over the years.
https://themotordigest.com/do-tesla-cars-use-ac-or-dc-motors/
That is a fascinating video and engine design.
It seems that gasoline/diesel engines evolved in many ways just as the steam engines did.
The Commer reminds me of the John Ericsson's Monitor (ironclad) engine in some respects.
Pat, I can see the "similarity" - but other than cylinder to crank arrangement of levers, the engines are entirely different. In the Ironclad engine, 2 separate chambers are pressurised separately to develop power. These are phased at 90 degrees for straightforward starting when Steam is supplied. The centre barrier separates the 2 chambers so the act independently. Whereas in the Commer diesel, Napier Deltic, etc, a common chamber between pistons is pressurised, with no central barrier, thus the 2 pistons must be synchronised and are dependent upon being in phase.
The significant disadvantage realised by the Commer application was that significant power was used in accelerating and decelerating all the moving mass of the levers, which necessarily had to be massive and stiff to work reliably. Cost also became an issue. But the forced air piston (exhaust) ported 2-stroke diesel in a more conventional configuration exists today in many ships - with some of the biggest engines in use.
Thanks for the ideas though.
K2
https://www.marinesite.info/2020/04/actual-pv-diagrams-of-4-stroke-and-2.html
The significant disadvantage realised by the Commer application was that significant power was used in accelerating and decelerating all the moving mass of the levers, which necessarily had to be massive and stiff to work reliably. Cost also became an issue. But the forced air piston (exhaust) ported 2-stroke diesel in a more conventional configuration exists today in many ships - with some of the biggest engines in use.
Thanks for the ideas though.
K2
https://www.marinesite.info/2020/04/actual-pv-diagrams-of-4-stroke-and-2.html
On PMSR electric motors, it is curious to me that the pulsations from the inverter/power supply to the Permanent Magnet DC motors actually use variable frequency pulses. In fact the pulsed DC for the PMSMs is approximately an AC waveform off-set by 1/2 the peak voltage of the wave-form. I can envisage these as very similar to the variable speed AC Thyristor controls used to start Pump Generators used in pumping mode of pumped storage power stations. Imagine starting a pump (that in reverse is a 132Mw water turbine generator!) - that starts effectively as an AC motor (~300Mw), from 1/3rd Hz AC (that's 1 cycle in 3 seconds on each of 12 poles = 1 revolution in 36 seconds!) at a few thousand Amps, accelerating to 500rpm, 50Hz AC at 18kv in 2.5 minutes. that is some variable speed controller and AC motor! - A real Testament to Tesla's genius?
And no commutator... no DC.
K2
https://www.fhc.co.uk/en/power-stat...sed of 16km,Europe's largest man-made cavern.
And no commutator... no DC.
K2
https://www.fhc.co.uk/en/power-stat...sed of 16km,Europe's largest man-made cavern.
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About 10 years ago Brian Rupnow and I each built a single cylinder 2 piston engine based on the Commer geometry but with spark ignition. His was 3/4 inch bore and mine was 3/8 inch bore. Fun project and fun to watch. Here is a video of mine.
Gail in NM
Gail in NM
grahamgollar
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Mechanicboy
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Semi-desel engine is a hot bulb engine who has low compression and using the hot bulb to ignite the fuel.
Roger B
Well-Known Member
Akroyd developed the following:
- Induction of air into the cylinder.
- Injection of liquid fuel into a heated combustion chamber where it vaporised.
- Compression to a few bar during which time the air and the vaporized fuel mixed.
- Ignition caused by the heated combustion chamber.
This development resolved a few problems at the time:
- The fuel did not have to be vaporised outside the combustion chamber.
- Avoiding pre ignition which allowed a higher compression ratio than spark or hot tube engines.
It was not cold starting and required several minutes heating with a blowlamp.
It was not very fuel efficient due to the still low compression ratio.
This is a hot bulb engine. These were gradually developed with higher compression ratios and smaller 'heated areas' and become known as semi diesels.
Diesel developed the following:
- Induction of air into the cylinder.
- Compression of the air to a temperature where the injected fuel would self-ignite.
- Injection of the fuel into the pressurised and heated air.
- Control of the maximum cylinder pressure during injection.
- Maximum expansion of the combustion products to maximise fuel efficiency.
The engine was cold starting and instantly available.
The engine had the highest efficiency at the time.
Other than the induction of air alone it is significantly different to the Akroyd version.
There are a number of incorrect statements about Diesel’s work. His book ‘Die Entstehung des Dieselmotors’ from 1913 gives the correct information.
https://www.hs-augsburg.de/homes/harsch/germanica/Chronologie/20Jh/Diesel/die_eda1.html
The first trials were made with the injection of benzine (I would translate this as kerosene) as a liquid. Due to the poor atomization the combustion was uncontrolled which resulted in the failure of the pressure indicator with a part flying in the direction of Diesel and his colleague. The engine itself was undamaged, as he states ‘it was built like a cannon’. They were happy that the fuel was ignited by the compression pressure.
Much further work was carried out on the fuel injection system to obtain satisfactory atomisation of the fuel when injected into a very high pressure cylinder. This problem was not addressed by Akroyd as in his engine the fuel was injected at low pressure into a heated chamber where it was vaporised.
Diesel’s final solution at this time was air blast injection which gave satisfactory atomisation and control of combustion with the added complication of a high pressure air compressor.
At the end of the book he describes a brief experiment with coal dust as a fuel. He was requested to do this as coal dust was cheap and plentiful. The trials were not successful.
- Induction of air into the cylinder.
- Injection of liquid fuel into a heated combustion chamber where it vaporised.
- Compression to a few bar during which time the air and the vaporized fuel mixed.
- Ignition caused by the heated combustion chamber.
This development resolved a few problems at the time:
- The fuel did not have to be vaporised outside the combustion chamber.
- Avoiding pre ignition which allowed a higher compression ratio than spark or hot tube engines.
It was not cold starting and required several minutes heating with a blowlamp.
It was not very fuel efficient due to the still low compression ratio.
This is a hot bulb engine. These were gradually developed with higher compression ratios and smaller 'heated areas' and become known as semi diesels.
Diesel developed the following:
- Induction of air into the cylinder.
- Compression of the air to a temperature where the injected fuel would self-ignite.
- Injection of the fuel into the pressurised and heated air.
- Control of the maximum cylinder pressure during injection.
- Maximum expansion of the combustion products to maximise fuel efficiency.
The engine was cold starting and instantly available.
The engine had the highest efficiency at the time.
Other than the induction of air alone it is significantly different to the Akroyd version.
There are a number of incorrect statements about Diesel’s work. His book ‘Die Entstehung des Dieselmotors’ from 1913 gives the correct information.
https://www.hs-augsburg.de/homes/harsch/germanica/Chronologie/20Jh/Diesel/die_eda1.html
The first trials were made with the injection of benzine (I would translate this as kerosene) as a liquid. Due to the poor atomization the combustion was uncontrolled which resulted in the failure of the pressure indicator with a part flying in the direction of Diesel and his colleague. The engine itself was undamaged, as he states ‘it was built like a cannon’. They were happy that the fuel was ignited by the compression pressure.
Much further work was carried out on the fuel injection system to obtain satisfactory atomisation of the fuel when injected into a very high pressure cylinder. This problem was not addressed by Akroyd as in his engine the fuel was injected at low pressure into a heated chamber where it was vaporised.
Diesel’s final solution at this time was air blast injection which gave satisfactory atomisation and control of combustion with the added complication of a high pressure air compressor.
At the end of the book he describes a brief experiment with coal dust as a fuel. He was requested to do this as coal dust was cheap and plentiful. The trials were not successful.
NapierDeltic
Well-Known Member
A very interesting concept of engine was/is free piston engine - experimented mostly in Diesel cycle - and whose most mature representative was Sigma GS-34: https://deepblue.lib.umich.edu/bitstream/handle/2027.42/107140/brandlee_1.pdf.
https://www.freikolben.ch/en/roberthuber.shtml
There are versions where hot exhaust gases power a turbine, or where "rotor" of an electric generator is directly actuated by piston. So actually, the generator is a linear alternative type and not rotary. Side forces, friction, wear and conversion losses are greatly reduced.
You can notice how smooth it runs (opposed pistons version which has a very good balance):
It seems that it was an engine ahead its time as proper control can only nowadays be achieved through electronic management, sensors, software... And gas turbines were in their infancy.
https://www.freikolben.ch/en/roberthuber.shtml
There are versions where hot exhaust gases power a turbine, or where "rotor" of an electric generator is directly actuated by piston. So actually, the generator is a linear alternative type and not rotary. Side forces, friction, wear and conversion losses are greatly reduced.
You can notice how smooth it runs (opposed pistons version which has a very good balance):
It seems that it was an engine ahead its time as proper control can only nowadays be achieved through electronic management, sensors, software... And gas turbines were in their infancy.
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