Ammonia – a new fuel for marine engines. First steps

Ammonia (NH3) is a colorless gas with a pungent, characteristic odor under normal conditions. In refrigeration, it is known as R717. Its density is 0,73 kg/m³, boiling point is -33,34°C, melting point is -77,73°C, vapor pressure is 861,262.5 Pa, and autoignition temperature is 651°C. Ammonia readily converts into a colorless liquid with a density of 681,4 kg/m³. When mixed with air, it is explosive (explosive limits are 15 vol.%), but it is safer than hydrogen.

Liquid ammonia is a good solvent for a very large number of organic and many inorganic compounds, and is corrosive to a number of metals. Since ammonia causes stress corrosion cracking (SCC), especially in carbon steels, low-yield strength steels or special alloys (e.g., 316L stainless steel) should be used. Copper, zinc, and their alloys (brass, bronze) are strictly prohibited, as ammonia rapidly corrodes them. Seals require special elastomers resistant to the chemical attack of ammonia.

Ammonia is a toxic substance with asphyxiating and neurotropic effects. Inhalation can cause toxic pulmonary edema (with exposure to ammonia at a concentration of 1,5 g/m³ for one hour) and severe damage to the nervous system. Ammonia vapors are highly irritating to the mucous membranes of the eyes and respiratory system, as well as the skin. Ammonia vapors cause profuse lacrimation, eye pain, chemical burns of the conjunctiva and cornea, vision loss, coughing fits, and reddening and itching of the skin. Contact with skin of liquefied ammonia and its solutions causes a burning sensation, and chemical burns with blisters and ulcerations are possible. Furthermore, liquefied ammonia absorbs heat as it evaporates, causing varying degrees of frostbite upon contact with skin. The maximum permissible concentration of ammonia vapor is 20 mg/m³.

The author of this article vividly recalls a case where a leak during loading of ammonia on a vessel with an ammonia refrigeration unit at the Klaipėda fishing port resulted in the death of a crew member. What an example of NH3's toxicity!

Ammonia is one of the most important chemical products, with global annual production exceeding 180 million tons. In 2024, 80% of the annual ammonia production was used in the chemical industry, primarily for fertilizer production, and 20% as a solvent for industrial purposes, as well as in refrigeration, energy, and medicine.

As we can see, ammonia's formula lacks sulfur and carbon, eliminating COx and SOx emissions during combustion. While NOx emissions are kept to acceptable levels, nitrous oxide (N2O), a gas 270 times more potent in greenhouse gases than CO2, can be formed. Nevertheless, ammonia is a smart choice for environmental protection. Furthermore, it can be produced using renewable energy sources—hydro, solar, and wind (so-called "green" ammonia, where hydrogen is extracted from water through electrolysis 2H2O → 2H2 + O2, which requires energy, and nitrogen is extracted from the air).

Production of "green" ammonia

However, safe handling of ammonia on ships will require the installation of complex and expensive safety equipment (detectors, shut-off valves to isolate leaks, double-walled fuel systems, etc.), specially designed fuel equipment, etc.

The energy density per unit volume of ammonia (12,7 MJ/L) is lower than that of diesel fuel (35 MJ/L). Transporting the same amount of energy as diesel fuel would require approximately 2,8 times the volume if the ammonia tank were refrigerated. At the same time, ammonia fuel will not present significant bunkering issues, as it is produced worldwide and transported through most major ports.

On board a ship, ammonia can be stored in liquid form at a pressure of 8,6 bar and a temperature of 20 °C. If the temperature exceeds this value, then for unrefrigerated tanks It is recommended to maintain a pressure of at least 18 bar.
All major diesel engine manufacturers, such as Everllence (formerly MAN Energy Solutions, and before that MAN Diesel & Turbo), Wärtsilä, Japan Engine Corporation (J-ENG), WinGD (Winterthur Gas & Diesel), etc., are working on developing (or converting existing) marine engines that run on ammonia.

By 2025–2026, classification societies (e.g., DNV, ClassNK, ABS) updated their rules, introducing specific notations regarding the use of ammonia as a fuel for marine engines. The International Maritime Organization (IMO) is also working on amendments permitting the use of toxic cargoes as fuel, and its interim guidelines (IGF Code) already take this experience into account.

As an example, let's consider the design features of Everllence's ME-LGIA ammonia dual-fuel, two-stroke, low-speed engine, based on the proven ME-LGIP engine. Development of the engine began in 2019, and bench testing of its single-cylinder section began in July 2023, followed by four-cylinder testing, and, starting in February 2025, the full-scale seven-cylinder 7S60ME-C10.5-LGIA-HPSCR (HPSCR — High Pressure Selective Catalytic Reduction for Tier III compliance).

Everllence's ME-LGIA four-cylinder section on a test bench

A full-scale seven-cylinder 7S60ME-C10.5-LGIA-HPSCR engine on a test bench

In the first quarter of 2026, the first such engine will be installed on a 200,000-dwt bulk carrier under construction at a Japanese shipyard. By the end of 2026, the ME-LGIA line is expected to be introduced to the market with cylinder sizes G50, S50, S60, G60, G70, and G80.

The main design difference between ammonia-powered engines and those running on conventional fuels is their fuel preparation system and fuel injection equipment. All engines mentioned in this article use a direct injection system for liquid ammonia into the combustion chamber at high pressure (300–600 bar or more) at the end of the compression stroke. High injection pressure (HPCR) improves ammonia atomization, reduces the level of unburned ammonia (slip), and achieves high thermal efficiency. A common rail system is typically used to deliver ammonia to the injectors.

Since ammonia has a high autoignition temperature (651°C, while diesel fuel has 225°C), diesel fuel is injected to initiate its combustion (usually about 5%, with ammonia providing the remaining 95% of the energy). Pilot fuel valves can be either separate or dual-fuel injectors, where diesel and ammonia are injected simultaneously or sequentially.

The working cycle of a two-stroke ammonia engine

Pilot fuel and ammonia injection system (dual-fuel injectors) for ME-LGIA engines from Everllence

Ammonia injection system for X-DF-A-1.0 engines from WinGD

Ammonia is supplied to the high-pressure fuel pumps (HPFPs) from the supply tank by the fuel pump, through filters and a heater, at a pressure of approximately 80 bar to prevent boiling. Given the low lubricating properties of ammonia, the plunger assemblies of the HPFPs must be made of special materials or use forced-air lubrication systems.

Because ammonia is highly toxic, all pipelines are double-walled, and the annular space is constantly purged with dehumidified air. Before maintenance, the system is purged with nitrogen to remove residual ammonia. Ammonia tanks are also double-walled or equipped with protective housings.

Ammonia engine fuel system

SCR technology is used to meet Tier III NOx emissions standards. SCR technology is an exhaust gas aftertreatment process in which nitrogen oxides (NOx) generated during combustion are removed from the exhaust gases through catalytic reduction. Typically, ammonia (a reducing agent) can be used as a catalytic agent and is injected into the exhaust gases. Ammonia consumption in the SCR system is very low compared to the consumption of ammonia fuel. During the catalytic reaction, NH3 and NOX are converted into nitrogen (N2) and water (H2O): 4NO + 4NH3 + O2 → 4N2 + 6H2O; 6NO2 + 8NH3 → 7N2 + 12H2O.

The working principle of SCR

To ensure crew safety when using ammonia, the following is required, in particular:

• Increased exhaust ventilation (up to 30 air changes per hour) in rooms with ammonia equipment. Air discharge should occur in safe areas, away from air intake points in living areas.

• In the event of ammonia discharge (through safety valves, during repair work), the gas should not be released directly into the atmosphere; it must be passed through water traps or scrubbers for absorption.

• A multi-level ammonia sensor-detector system capable of detecting ammonia concentrations well below the lower explosive limit (LEL) and toxicity threshold.

• Mandatory installation of water irrigation systems to “precipitate” the ammonia cloud in the event of a leak.

• The crew must be provided with chemical suits and isolating breathing apparatus.

• Classification societies require special training for crews (Ammonia Handling Training), which includes practicing ammonia spill response scenarios and first aid skills for chemical burns and poisoning.

In September 2025, the Japanese company J-ENG unveiled the 7UEC50LSJA-HPSCR dual-fuel two-stroke engine. Prior to this, its single-cylinder section and full-scale engine successfully completed over 1700 hours of rig operation using both ammonia and heavy fuel oil (HFO). A vessel equipped with this engine is scheduled for commercial operation in 2026.

7UEC50LSJA-HPSCR

Since 2024, WinGD has been offering a line of 5-9-cylinder, two-stroke, dual-fuel X-DF-A-1.0 diesel engines designed to run on ammonia, but also capable of running on HFO, MDO, and MGO. With cylinder diameters of 520-820 mm, speeds of 79-105 rpm, and a mean effective pressure of 21-22 bar, they produce power ranging from 5100 to 49500 kW.

In January 2026, the factory acceptance tests of the WinGD X52DF-A-1.0 engine were completed at the Hyundai Heavy Industries plant in South Korea. This engine will be installed on a 46,000m³ LPG/ammonia carrier.

WinGD's X52DF-A-1.0 on a test bench

X-DF-A-1.0 series engines

In the fall of 2024, South Korean company Hyundai Heavy Industries completed rig testing of the H22CDF-LA dual-fuel, medium-speed, four-stroke diesel engine designed to run on ammonia. These 6-9-cylinder engines can produce power from 1440 to 2160 kW at 900-1000 rpm, with units being developed with outputs up to 5,4 MW. An SCR system is used to reduce NOx and unburned ammonia emissions.

Engine type H22CDF-LA

In 2024, Wärtsilä introduced the Wärtsilä 25, a four-stroke dual-fuel diesel engine capable of running on ammonia. It can be used as a main engine on small vessels or to drive electric generators. This medium-speed in-line engine is available with 6 to 9 cylinders and produces power from 1,7 to 3,4 MW. The engine is supplied with the Wärtsilä NOx Reducer (NOR) system to meet IMO Tier II and III requirements.

Wärtsilä 25 engine

The first vessel to be powered by this engine will be the Viking Energy, a platform supply vessel (PSV) owned by the Norwegian company Eidesvik Offshore. The conversion of this 95-meter PSV, built in 2003, is scheduled to begin this spring and be completed in the fall of 2026.

The design documentation has already received preliminary approval from the Norwegian Maritime Authority. Furthermore, the classification society DNV has issued in-principle approval for the ammonia-fueled vessel's design.

Comments

[Inj Meh]

The ideal option for Europe is to build a chemical crematorium on its own territory at its own expense, with the idea of ​​eliminating hydrocarbons and storing renewable energy in ammonia.

What a gift this will be for the enemies!

[Civil]

1. It is impossible to imagine such an engine on passenger ships.
2. What will happen when most ships are converted to ammonia and, after their primary fuel is exhausted, resold to third-world countries? There won't be any alternative...

[Inj Meh]

Another question has been tormenting me since childhood:

Why is it impossible to use cooling water (steam) as an additional working fluid in hydrocarbon/hydrogen internal combustion engines with a long piston stroke after the combustion process in the two-stroke cylinder is completed?

I guess I just wasn't looking for such engines.

The cycle is roughly like this (diesel-steam-ship🤭)
1. Purging the cylinder with air from the turbocharger
2. Compression
3. Injection and ignition of fuel from the high-pressure fuel pump
4. Fuel combustion "in the middle" of the piston stroke
5. Injection of water (pre-heated and "compressed" into the high-pressure fuel pump) from the cooling system
6. Vaporization with accompanying cooling of the piston and the inner cylinder wall
7. Relieving pressure at the bottom dead center of the piston stroke
8.=1. Blowing air from the turbocharger into the cylinder

I understand that there will be questions about the weight, size, and temperature limitations of land-based vehicles, but I don't see any particular obstacles for water transport (naturally, due to my own amateurism).

[Luminman]

Quote: Eng Mech

Why is it impossible to use cooling water (steam) as an additional working fluid in hydrocarbon/hydrogen engines with a long piston stroke after the combustion process in the two-stroke cylinder is completed?

There is a more effective method for this that kills several birds with one stone - injection of nitrous oxide into the combustion chamber, which cools and prevents possible detonation, contains more oxygen than air, increases engine power, and allows fuel to burn more efficiently. And it doesn't require additional devices like a turbocharger...

[the same doctor]

Your idea is incorrect. You need to inject water, not nitrous oxide. In our winter climate, a water-alcohol solution is required. First the fuel, then the alcohol. However, this would require doubling or complicating the fuel system. While the fuel system is imported, it's unprofitable.

The goal isn't to increase power, but to reduce wear by lowering exhaust gas temperatures. Efficiency might also increase.

[Inj Meh]

Quote: also a doctor

First fuel, then alcohol. However, this will require doubling or increasing the complexity of the fuel system. While imported fuel system is unprofitable, it's not cost-effective.

Yes, it probably didn’t work out due to the complexity of the additional component supply system.

Yes, but the goal is to ultimately increase efficiency by having a free second component (water), which only requires preliminary fine filtration/distillation

But besides this, I also meant:
1. Obtaining additional energy through the operation of steam and heat recovery, which (steam) in the form of preliminary heating in the engine cooling circuit and evaporation (I'm not so sure about this) cools the most heat-loaded parts of the internal combustion engine (piston, head and inner cylinder wall) and performs additional work by pushing the piston (i.e. slows down the process of lowering the pressure in the piston after the fuel combustion in the section closer to the NMP has actually ceased)
2. Reduced wear through compression and engine speed due to a longer piston stroke.
3. Reduction of losses by reducing the engine cycle and losses in the cooling system

An alcohol solution won't hurt, as it will also lower the potential freezing point, but it will require special logistical measures, given the "peculiarities of national filling" with this liquid.

[the same doctor]

Your design doesn't fit into existing designs. However, injecting up to 20 percent of the fuel's weight in water or alcohol can be implemented in any engine. I've been hearing these ideas since the 30s, and they've been proven. SIMPLE drippers in the intake manifold, as well as fuel-water emulsions, have been used.
The only novelty in your idea is to inject after the fuel has ignited, which is quite good, but requires doubling or complicating the fuel equipment.
Your fantasies about fuel combustion in a cylinder are, unfortunately, far from reality.

[Inj Meh]

Quote: also a doctor

Your design doesn't fit into existing designs. However, injecting up to 20 percent of the fuel's weight in water or alcohol can be implemented in any engine. I've been hearing these ideas since the 30s, and they've been proven. SIMPLE drippers in the intake manifold, as well as fuel-water emulsions, have been used.
The only novelty in your idea is to inject after the fuel has ignited, which is quite good, but requires doubling or complicating the fuel equipment.
Your fantasies about fuel combustion in a cylinder are, unfortunately, far from reality.

Maybe (combustion and its optimization is generally a very complex thing, especially in a closed but changing volume).

Probably the quantitative and qualitative composition of the fuel-air mixture in the cylinder and the duration of the part of the cycle allocated for combustion (≈piston stroke) are important.

I don't remember what the consequences of too much air are.

[ln_ln]

and the duration of the part of the cycle allocated for combustion (≈piston stroke)

Combustion should end before TDC. Afterburning at the expansion line is very bad.

I don't remember what the consequences of too much air are.

There's no danger. Even at maximum cyclic flow, a diesel engine operates with an excess air ratio of about 1,5. And at partial loads, it's even higher.

[Inj Meh]

Quote from: ln_ln

Combustion should end before TDC. Afterburning at the expansion line is very bad.

It seems to be an early ignition/ignition effect depending on which stroke you mean.

I'm talking about a two-stroke engine.

I'm certainly not an engine specialist, but I have a strong feeling that before the cylinder NMT

That is, according to my data, the combustion process of diesel fuel consists of several phases.
1. Start of fuel injection into the cylinder before TDC
2. Spraying/evaporation => the actual formation of the air-fuel mixture and ignition (probably before TDC, but most likely it was calculated so that it was almost at TDC)

3. The combustion itself (with possible injection of fuel in portions to maintain high pressure in the cylinder along its stroke to the top dead center), i.e. at any point after TDC

This is the essence of the idea that, roughly speaking, instead of the last portion of fuel, inject superheated water and cool the internal surfaces of the combustion chamber while using the energy of steam to maintain pressure and push the piston to the NMH

4. Then comes the blowdown in a two-stroke
Or
Exhaust through the valve during the piston's upward movement in a four-stroke engine. Naturally, this could result in completely useless combustion of the remaining fuel. But as far as I understand, this is incorrect and should not happen.

[ln_ln]

According to my data, the combustion process of diesel fuel consists of several phases

Unfortunately, your data is incorrect.
A diesel engine uses heterogeneous mixture formation. A homogeneous air-fuel mixture is not formed in the diesel process, and it is pointless at excess air ratios of 1,5 or more (such a mixture is beyond the flammability limit). The mixture burns in layers as the droplets evaporate in the zone where combustion is possible.

The combustion itself (with possible injection of fuel in portions to maintain high pressure in the cylinder along its stroke to the top dead center), i.e. at any point after TDC

Let me repeat, there should be no combustion during expansion.
The exhaust valves or windows begin to open at about 60 degrees BC.
And the pressure is already falling, and the leverage is already halved.
And it’s better to save the energy of gases for turbocharging.

[Inj Meh]

Quote from: ln_ln

According to my data, the combustion process of diesel fuel consists of several phases

Unfortunately, your data is incorrect.
A diesel engine uses heterogeneous mixture formation. A homogeneous air-fuel mixture is not formed in the diesel process, and it is pointless at excess air ratios of 1,5 or more (such a mixture is beyond the flammability limit). The mixture burns in layers as the droplets evaporate in the zone where combustion is possible.

The combustion itself (with possible injection of fuel in portions to maintain high pressure in the cylinder along its stroke to the top dead center), i.e. at any point after TDC

Let me repeat, there should be no combustion during expansion.
The exhaust valves or windows begin to open at about 60 degrees BC.
And the pressure is already falling, and the leverage is already halved.
And it’s better to save the energy of gases for turbocharging.

Everything is possible in this world
Even this is possible.

But with your tacit permission, I will stick to the classic version.

"
§ 5. The design and operation of a two-stroke diesel engine

The working cycle of a two-stroke diesel engine is completed in two piston strokes or one crankshaft revolution. Therefore, at the same RPM, the number of working strokes in a two-stroke diesel engine will be twice that of a four-stroke diesel engine. During the working cycle of a two-stroke diesel engine, the same processes occur as in a four-stroke engine: filling, compression, combustion, expansion, and exhaust.

Because all processes must be completed within two piston strokes, the design of a two-stroke engine has some unique features (Fig. 1.6). The lower portion of cylinder 1 contains slots (slits) called ports. The taller ports 4 serve to release exhaust gases from the cylinder, while the smaller ports 6 are designed to admit fresh (scavenge) air. Injector 3 is located in cylinder cover 2. Pipe 5, called a receiver, is attached to the left side of the lower portion of the cylinder and receives scavenge air.




To prepare scavenging air at a pressure of p = 0,124 ÷ 0,13 MN/m ≈ 1,2 ÷ 1,3 kgf/cm, special air pumps called scavenging pumps are used. In low-power engines, this air is prepared in the space beneath the piston during its downward stroke.

Fig. 1.6. Diagram of the operation of a two-stroke diesel engine.


A two-stroke engine operates as follows. When the piston passes TDC, combustion of the fuel begins in the cylinder (point c on the indicator diagram), ending at point z. From point z to point b, the gases expand, and the piston moves downward under the pressure of the gases. As can be seen from the diagram, at point b, the expansion of the gases ends, the piston opens the exhaust ports, and the pressure in the cylinder quickly drops to the scavenging air pressure p. After the exhaust ports open, the gases expand along the line be. When the pressure in the cylinder becomes equal to the scavenging air pressure (point e), the piston opens the scavenging ports and air intake begins. Filling the cylinder with a fresh charge while simultaneously releasing exhaust gases is called scavenging.

From the moment the scavenging ports open until they close as the piston moves toward TDC, gases are simultaneously exhausted and a fresh charge is admitted. This process is depicted in the diagram by line efe. After the scavenging ports close, only exhaust occurs (line ea). At point a, the exhaust ports close, and compression of the air that entered the cylinder during the scavenging period begins.

Let's take a closer look at the working cycle of a two-stroke engine.

The first stroke - the piston moves upward. From BDC to the moment the intake ports close (point e on the diagram), scavenging occurs, i.e., simultaneously cleaning the cylinder of combustion products and filling it with a fresh charge. As the piston moves from the upper edge of the intake ports to the moment the exhaust ports close (section ea on the diagram), only exhaust occurs. After the exhaust ports close, compression begins, continuing until TDC. In the diagram, compression is shown by line ac. At the end of compression, slightly before TDC, fuel is supplied to the cylinder.

The second stroke - the piston moves downward. Starting from TDC, fuel combustion (line cz) and gas expansion (line zb) occur sequentially in the cylinder. At point b, the exhaust ports open and gas exhaust begins. By the time the piston opens the intake ports (point e), the gas pressure in the cylinder must drop to the scavenging air pressure ps; otherwise, the gases will enter the receiver through the intake ports, mix with the scavenging air, and contaminate the fresh charge. As the piston continues to move downward (section ef of the diagram), scavenging occurs. The full scavenging period is shown on the diagram by line efe, with section ef corresponding to the piston's downward movement and section fe corresponding to its upward movement.

The pressure and temperature that characterize the working process of a two-stroke diesel engine are the same as those of a four-stroke engine, with the exception of the pressure and temperature of the fresh charge at the beginning of compression, which are somewhat higher.

As can be seen from Figure 1.6, the indicator diagram of a two-stroke engine differs from that of a four-stroke engine in that the intake and exhaust lines do not occupy the entire piston stroke. Furthermore, the section of the diagram at the bottom dead center has a different appearance. The nature of the compression, combustion, and expansion processes, which determine the area of ​​the diagram, is the same as for a four-stroke engine.

The design of the scavenging elements depends on the type and power of the diesel engine. They are discussed in detail when studying the distribution system.
"

https://studfile.net/preview/7850070/page:5/

[ln_ln]

But with your tacit permission, I will stick to the classic version.

I didn't quite understand what was "non-classical" in what I wrote.
And why repeat generally known information at such length?

[Inj Meh]

Quote from: ln_ln

But with your tacit permission, I will stick to the classic version.

I didn't quite understand what was "non-classical" in what I wrote.
And why repeat generally known information at such length?

Apparently you just need to argue for the sake of arguing.
I'm not interested

I admit that the diagram is too conditional.
But according to it, a sharp increase in pressure (combustion) begins at TDC and continues for some time as the piston moves downwards (diagram sections c-z'-z)

The exhaust ports open with the piston after the middle of the downward stroke, i.e., the crankshaft rotation is more than 120° after TDC. It seems less than 60 BC

The solutions with valves you described are also available.

[ln_ln]

I admit that the diagram is too conditional.
But according to it, a sharp increase in pressure (combustion) begins at TDC and continues for some time as the piston moves downwards (diagram sections c-z'-z)

The diagram is idealized.
But where is the “sharp increase in pressure” in the z'-z section?

[Inj Meh]

Quote from: ln_ln

I admit that the diagram is too conditional.
But according to it, a sharp increase in pressure (combustion) begins at TDC and continues for some time as the piston moves downwards (diagram sections c-z'-z)

The diagram is idealized.
But where is the “sharp increase in pressure” in the z'-z section?

c-z'-z or, if you prefer, c-z
Well, everything is clear with you.
Troll someone else

Can you send me the "correct" diagram in which combustion ends when the piston rises to TDC?

[Inj Meh]

Quote from: ln_ln

1. I repeat, there should be no combustion during expansion.

And it’s better to save the energy of gases for turbocharging.

If thesis 1. Implies the completion of the combustion process in the cylinder when the piston moves upward from the nit to the TDC (i.e., at TDC everything has already burned).

Plus (just in case, because I don’t remember whether you deny the possibility of multiple injections of diesel fuel into the cylinder or not)

Then perhaps you will be interested in asking the following (if it is not fake, of course)

https://common-rail.blogspot.com/2011/11/common-rail_24.html?m=1

I did not copy the text for your convenience.

All kinds of outlet and blow-off angles are a matter of organizing the "air exchange" process in a specific cylinder model and are relatively flexible, as far as I understand.

[ln_ln]

https://common-rail.blogspot.com/2011/11/common-rail_24.html?m=1

This is something...

[Inj Meh]

Quote from: ln_ln

https://common-rail.blogspot.com/2011/11/common-rail_24.html?m=1

This is something...

Well, everything is clear with you.
Troll someone else

[ln_ln]

Well, everything is clear with you.

I'm not sure you understand anything. This text is a jumble of nonsense.
And the injection diagram is not tied to either the crankshaft angle or the piston stroke.

[Inj Meh]

Quote from: ln_ln

Well, everything is clear with you.

I'm not sure you understand anything. This text is a jumble of nonsense.
And the injection diagram is not tied to either the crankshaft angle or the piston stroke.

So this can be solved with the correct and linked diagram provided by you.

Your word (illustrated with a diagram with angles and everything that is important to you) to the Studio!

[Inj Meh]

Quote from: ln_ln

And the injection diagram is not tied to either the crankshaft angle or the piston stroke.

I wonder what this injection linkage will give you in proving the alternative theory of combustion ending in the piston before TDC during the compression stroke.

[Inj Meh]

Quote from: ln_ln

Well, everything is clear with you.

I'm not sure you understand anything. This text is a jumble of nonsense.
And the injection diagram is not tied to either the crankshaft angle or the piston stroke.

I wonder what you have to say about this.

[ln_ln]

I wonder what you have to say about this.

Detonation in diesel engine???
It is a masterpiece.

I changed the fuel injection pump and set the injection start angle according to the data sheet to about 20° (I don’t remember exactly, it was about 20 years ago).
The KIA diagram shows about 2° (two degrees). This may be true at idle.

[ln_ln]

I clarified according to the instructions:
"Start of fuel supply by the third left section of the fuel pump
must correspond to the position of the piston of the third left cylinder
24…25° before TDC on the compression stroke."

[Inj Meh]

Quote from: ln_ln

I clarified according to the instructions:
"Start of fuel supply by the third left section of the fuel pump
must correspond to the position of the piston of the third left cylinder
24…25° before TDC on the compression stroke."

Well, let's stop here.

[Inj Meh]

Quote from: ln_ln

https://common-rail.blogspot.com/2011/11/common-rail_24.html?m=1

This is something...

https://www.sinref.ru/000_uchebniki/05300_transport_jd_teplovozi/000_kak_ustroen_i_rabotaet_teplovoz_drobinski_1980/022.htm

Still, peasant children are always and everywhere strange.

The picture shows the pressure of a four-stroke engine, but this does not change the essence of the combustion process.

[Inj Meh]

Quote from: ln_ln

and the duration of the part of the cycle allocated for combustion (≈piston stroke)

Combustion should end before TDC. Afterburning at the expansion line is very bad.

I don't remember what the consequences of too much air are.

There's no danger. Even at maximum cyclic flow, a diesel engine operates with an excess air ratio of about 1,5. And at partial loads, it's even higher.

For general development, you can also familiarize yourself with this "nonsense"
TDC === tds
https://ppt-online.org/1515575

[Luminman]

Quote: also a doctor

You need to inject water, not nitrous oxide.

The date entry gives the same engine characteristics as water, only an order of magnitude better...

Quote: also a doctor

The goal is not to increase power.

What's wrong with increasing engine power if you don't have to resort to additional mechanisms?

[Dedok]

Why is it impossible to use cooling water (steam) as an additional working fluid in hydrocarbon/hydrogen internal combustion engines with a long piston stroke after the combustion process in the two-stroke cylinder is completed?

There were such studies in the USSR, but at that time they were considered unnecessary...

[ALEKS112233]

Comrade engineer! Why not? Yes, yes! They wrote a lot about this in the 70s! I was younger then and didn't get into many of the processes. Moreover, you probably know, our DIYers even added water to car engines, to their fuel systems! Get to it!

[Inj Meh]

Quote: ALEKS112233

Comrade engineer! Why not? Yes, yes! They wrote a lot about this in the 70s! I was younger then and didn't get into many of the processes. Moreover, you probably know, our DIYers even added water to car engines, to their fuel systems! Get to it!

"Get busy" sounds tempting.
Again, who needs this?
The hydrocarbon will not bless.

And developing an engine (even in preliminary drawings) is far from a piece of cake.

Besides this, according to my understanding and that of comrade doctor, the existing internal combustion engines are not very suitable due to their piston-like short stroke.

Roughly speaking, engine power is now more focused on increasing revolutions (≈decreasing piston stroke)

I am profoundly mistaken that the water-added approach will work more or less effectively only on relatively long-stroke pistons (=> increased dimensions and weight of the internal combustion engine, which is not very critical on ships and railway diesel locomotives, but is very critical on classic wheeled and tracked vehicles)

However, an exception may be made for boxer engines in which each cylinder has two converging and diverging pistons (I don’t remember what they’re called).

In general, I already said that this question has been tormenting me for a long time, so I asked it here so that someone could explain to me in simple terms that this is impossible or send me a link to an explanation so that I can stop suffering.

[Motorist]

Quote: Eng Mech

I don't see any particular obstacles regarding water transport

1. Water in the cooling system with expensive additives, you will be tormented with water treatment.
2. The water won't boil there much, the temperatures are low at this stage, and heat exchange will be poor (don't forget about the latent heat of vaporization).
3. There is nothing to cool there (see above).
4. And, most importantly: water inside the engine (if not cooling) is harmful (sulfuric acid and other corrosion, washing away of cylinder oil from the bushing and rings, disruption of rod lubrication, disposal of waste into the sub-piston).

[Inj Meh]

Quote: Motorist

Quote: Eng Mech

I don't see any particular obstacles regarding water transport

1. Water in the cooling system with expensive additives, you will be tormented with water treatment.
2. The water won't boil there much, the temperatures are low at this stage, and heat exchange will be poor (don't forget about the latent heat of vaporization).
3. There is nothing to cool there (see above).
4. And, most importantly: water inside the engine (if not cooling) is harmful (sulfuric acid and other corrosion, washing away of cylinder oil from the bushing and rings, disruption of rod lubrication, disposal of waste into the sub-piston).

Of course, I can’t justify it mathematically, I’m just reasoning in the following logic:

"Instead of wasting energy on external cooling, we can try to "recover" it in the described way into useful energy/increasing efficiency through "internal cooling." Ideally, we could abandon the external hydraulic cooling system altogether."

Regarding your antitheses (which are quite reasonable):
1. Because it's in a closed cooling system and designed for a relatively long service life. In the "diesel-steam" version, the water is preheated/superheated in the cooling jacket and injected into the cylinder under pressure.
2. According to my data, the temperatures of the internal surfaces of the piston can be 300-400°C, the walls and cylinder head are lower, but precisely because they are externally cooled, i.e. there can also be variations.
2.1 The energy of vaporization is solved by the correct amount of water injected into the cylinder at a known temperature
3. There is something (for example, a piston) and an increased temperature of the cylinder walls (due to the new cooling system)
4. The combustion products of hydrocarbons (including ) consist of water vapor (and the same set of acids). Theoretically, increasing the amount of water vapor in the cylinder, due to the addition of water, should reduce the concentration of acid vapor. Regarding lubrication issues, it's difficult to say right away, but I don't think it's a fundamental problem.

In any case, thanks for the constructive opposition.

It's always a pleasure to talk to smart people.

[Motorist]

Good time!

1. The cooling water must contain corrosion inhibitors. And what are you trying to overheat it with—iron from the bushings and covers? Then the point of cooling is completely lost; you'll need other, more expensive materials.

2. So you want to spray water on the walls?! I'm not taking part in such an adventure.

2.1. The point is that you'll have to inject tiny amounts of fuel—little heat and time. The temperature in the cylinder at the end of the expansion phase is very low.

3. See above.

4. That "natural" steam is superheated, reducing the likelihood of condensation. Hopefully, most of it will have time to leave the cylinder before you inject. Otherwise, it will all condense together, and that's it.

And thank you for the conversation.

[Inj Meh]

Quote: Motorist

Good time!

1. The cooling water must contain corrosion inhibitors. And what are you trying to overheat it with—iron from the bushings and covers? Then the point of cooling is completely lost; you'll need other, more expensive materials.

2. So you want to spray water on the walls?! I'm not taking part in such an adventure.

2.1. The point is that you'll have to inject tiny amounts of fuel—little heat and time. The temperature in the cylinder at the end of the expansion phase is very low.

3. See above.

4. That "natural" steam is superheated, reducing the likelihood of condensation. Hopefully, most of it will have time to leave the cylinder before you inject. Otherwise, it will all condense together, and that's it.

And thank you for the conversation.

Well, let it be so.

[Motorist]

Quote: Eng Mech

Well, let it be so.

Indeed, there's no need to torment ship mechanics and engine mechanics. They come up with all sorts of things: scrubbers, catalysts, methanol, ammonia, 5 parts per million SLVs, checklists, risk assessments, bullying and harassment...

I often remember the film "Striped Trip", what a time it was!

[Inj Meh]

Quote: Motorist

Quote: Eng Mech

Well, let it be so.

Indeed, there's no need to torment ship mechanics and engine mechanics. They come up with all sorts of things: scrubbers, catalysts, methanol, ammonia, 5 parts per million SLVs, checklists, risk assessments, bullying and harassment...

I often remember the film "Striped Trip", what a time it was!

What do you know/have you heard about Dimethyl Ether (DME) as a diesel fuel replacement?

[Motorist]

I don't know, I'm an operator. My lot is fuel oil and diesel fuel, or the slop made from them. There's also all sorts of "bio" stuff (of various types and qualities, too), but I haven't encountered it personally yet.

[Inj Meh]

Quote: Motorist

Good time!

1. The cooling water must contain corrosion inhibitors. And what are you trying to overheat it with—iron from the bushings and covers? Then the point of cooling is completely lost; you'll need other, more expensive materials.

2. So you want to spray water on the walls?! I'm not taking part in such an adventure.

2.1. The point is that you'll have to inject tiny amounts of fuel—little heat and time. The temperature in the cylinder at the end of the expansion phase is very low.

3. See above.

4. That "natural" steam is superheated, reducing the likelihood of condensation. Hopefully, most of it will have time to leave the cylinder before you inject. Otherwise, it will all condense together, and that's it.

And thank you for the conversation.

By the way, here's what tdip siik "thinks" about this

Yes, corrosion and lubrication problems are probably the biggest problem identified so far.

"
Water injection into a diesel engine cylinder is not a new technology, but it periodically returns to the forefront of engineering thought. It does solve several key problems: reducing toxicity (especially nitrogen oxides), removing heat from overloaded components, and, in some systems, increasing power by harnessing steam energy.

Below is an overview of the main experiments, their results and physical principles.

---

1. The main purposes of water injection

Experiments have three main goals, which are often implemented simultaneously:

1. Reducing combustion chamber temperature to suppress NOx:
Nitrogen oxides (NOx) form at local temperatures above 2000°C. Water evaporation removes a significant amount of heat (the heat of vaporization), reducing the peak temperature in the combustion zone. This is the most studied and proven effect.
2. Cooling (forcing) the thermal regime:
Water cools the cylinder walls, head, and piston from the inside. This allows either the elimination of a bulky external cooling system (radiator) or increased engine reliability under extreme loads.
3. Utilization of heat and performance of useful work:
Water turns into steam, which expands and pushes the piston. In a classic four-stroke cycle, the effect is minimal, but in special cycles (such as six-stroke cycles), the steam performs a separate power stroke.

---

2. Design schemes and experiments

Depending on the moment and location of injection, there are several approaches:

A. Direct injection into the combustion chamber (Direct Water Injection - DWI)

This is the most common method in experiments. An additional high-pressure injector is installed in the cylinder (or a combined fuel-water injector is used). Water is injected either simultaneously with the fuel or immediately after combustion begins.

· CFD modeling results (SAE 2000-01-2938) showed:
· Reduction of NOx in all modes.
· Increase in jet penetration by 35% when replacing 23% of the fuel volume with water due to the increase in charge density and latent heat of vaporization.
· Risk of soot growth with late injection at high loads.

B. Water injection for internal cooling (Evaporative In-Cylinder Cooling)

Engineering developments (for example, Douglas Thorpe's patents) suggest injecting water not directly into the flame, but into special channels inside the piston or onto the cylinder walls.

Concept: Water is injected under pressure of 135–500 MPa into the cavities beneath the piston crown. Evaporating from the heat of the metal, the steam cools the piston, creating a gas cushion between the piston and the wall (replacing the oil), and some of the steam then enters the combustion chamber, performing work.
· Calculation ratio: For 1 part fuel, it is recommended to use 4 to 7 parts water.

B. Six-Stroke Engines

This is a separate line of experiments, where water is used not as an additive, but as a working fluid for an additional stroke.

· Cycle: 4 normal strokes (intake-compression-power stroke-exhaust) + 5th stroke (water injection into the hot cylinder) + 6th stroke (steam power stroke).
Results: A literature review (2024) showed that this design increases braking power by 5.18% and thermal efficiency by 1.55% (using acetylene fuel). However, the researchers note that experimental setups are few, and most studies exist in the form of analytical models.

---

3. Unexpected effects and thermodynamic nuances

Contrary to the intuitive expectation that "cooling reduces efficiency," experiments show a complex picture.

· Increase in indicated efficiency:
A study modeling a medium-speed marine diesel engine (KhPI, 2010) demonstrated that injecting water immediately before closing the intake valve (compression charge cooling) increases power and reduces thermal stress on the components. The steam not only "dissipates" heat, but also participates in the expansion process, increasing the overall pressure.
· Debunking the myth of loss of efficiency:
The Marine Engine Technical Seminar (1996) states: "I would venture to say that water injection has no disadvantages in terms of thermal efficiency if the process is sufficiently controlled." The steam generated from the water is the same working gas as the combustion products, and its expansion compensates for the heat lost due to evaporation.

---

4. Limits of applicability: Why water won’t replace fuel?

The question periodically arises on forums and in DIY experiments: "Is it possible to inject only water using the heat of compression?" (as in the discussed post on REAA.ru).

The answer from heating engineers is clear: the engine cannot operate on water alone without an external heat source. The reason is the law of conservation of energy:

1. Heat capacity: It takes a huge amount of heat to heat, evaporate and superheat water.
2. Balance: In a diesel engine, heat is released during fuel combustion. If the fuel is removed, the only heat source is the work of compressing the air (adiabatic compression). However, when expanding the steam, the work we obtain is less than the work expended on compressing the air and evaporating the water, due to losses.
3. Conclusion: Such an installation will not be an engine, but a steam engine that requires external heating (like a steam locomotive).

---

5. Summary: Experimental Results

Summary of the reviewed scientific papers and patents:

Parameter Effect of water injection Source
Toxicity (NOx) Reduction (Main Effect)
Power / Efficiency Small increase (up to +5.18% with optimization) or maintained at the standard level
Temperature of parts decreases (allows you to remove the radiator or boost the engine)
Soot content: Ambiguous: depends on the injection time (may increase with late injection)
Resource (problem) Risk of corrosion and washout of the oil film (requires anti-corrosion additives and precise dosage)

Conclusion
Experiments with water injection into diesel cylinders confirm that it is an effective tool for environmental tuning (NOx reduction) and for removable cooling. Using the "vapor effect" to increase power is possible, but requires either complex six-stroke systems or precise injection control within the standard cycle. The idea of ​​replacing fuel with water is thermodynamically untenable without an external heat source.
"

[Motorist]

Quote: Eng Mech

By the way, here's what tdip siik "thinks" about this

Deep Seak forgot to ask my Alice - he would have learned a lot of new words. Yes, they demand N-O-X from us, and also S-O-X. And a whole bunch of other pseudo-ecological crap. And all this doesn't make my job any easier, quite the opposite. This is where "the perfect is the enemy of the good."

[Inj Meh]

Quote: Motorist

Quote: Eng Mech

By the way, here's what tdip siik "thinks" about this

Deep Seak forgot to ask my Alice - he would have learned a lot of new words. Yes, they demand N-O-X from us, and also S-O-X. And a whole bunch of other pseudo-ecological crap. And all this doesn't make my job any easier, quite the opposite. This is where "the perfect is the enemy of the good."

Maybe it's for the best, Alice is still in her own looking glass, in my opinion.

NOx also refers to aggressive acids.

H2NOx

Well, in general, theoretically it is possible.

It seems that the lubricant can be injected together with water.

Parking corrosion is solved by blowing/(coasting the air compressor) while the engine is idling before shutting it down

Diip siik is cool
"Below is a revised answer, taking into account the clarified context: water injection occurs after combustion has ceased, in order to obtain additional work from the expanding steam and simultaneously cool the internal surfaces of the combustion chamber through vaporization. An opinion is also given on the applicability of this design in two-stroke diesel engines with a long piston stroke.

---

1. Electrochemical corrosion protection in the "steam working stroke" scheme

In the design under consideration, water is injected into the cylinder after the combustion phase is complete, when the gas and wall temperatures are still high and the pressure begins to decrease. This causes the water to evaporate rapidly, increasing the cylinder pressure again, and the steam performs additional work, expanding until the exhaust ports open.

From the point of view of corrosion risks, this regime creates specific conditions:

At the moment of injection and vaporization, liquid water is present for only a fraction of a second and turns into steam almost instantly. Classic electrochemical corrosion requires the presence of a liquid electrolyte, so it doesn't have time to develop during the process.
The main danger is static corrosion after the engine is turned off. Steam remaining in the cylinder and exhaust tract condenses on the cooling walls, forming a thin film of water in which aggressive combustion products (acids, sulfur and nitrogen oxides) are dissolved. This film is an ideal electrolyte.
· Electrochemical protection (cathodic or sacrificial) in the combustion chamber area during engine operation is practically impossible to implement: high temperatures destroy any galvanic anodes, and stable electrical contact with the liquid phase is absent.

However, there are engineering techniques that can reduce the corrosive effects:

1. Motor oil additives contain inhibitors that create an adsorption or chemical film on metal surfaces, neutralizing the electrolyte even when exposed to condensate. This is the primary method of protecting the cylinder-piston assembly in engines with water injection.
2. Volatile corrosion inhibitors (VpCI) are added to the fuel or injection water. They evaporate, deposit on all internal cavities, and protect the metal in the vapor phase, which is especially valuable for cylinders and the exhaust tract during downtime. These technologies are widely used in marine and stationary engines for preservation.
3. Sacrificial protection in the cooling system – if water from the combustion chamber penetrates the cooling jacket (through micropores or seals), installing zinc or magnesium anodes in the water path of the cylinder block effectively suppresses liner corrosion. This is a proven method for large diesel engines.
4. Selection of materials and coatings – the use of alloyed cast irons, Ni-resist, and ceramic coatings on piston crowns and heads eliminates the need for electrochemical protection “in the hot zone,” as they have high corrosion resistance.

Summary of the first part:
Electrochemical protection in the classic sense (applying an external current or installing protectors inside the cylinder) is ineffective for this application. Corrosion risks are successfully controlled with oil inhibitors, volatile inhibitors, and structural materials, while protectors are only appropriate in external circuits (cooling).

---

2. Efficiency of the circuit in two-stroke diesel engines with a long piston stroke

Two-stroke diesel engines (especially large marine ones like MAN B&W, Wärtsilä) have design and thermodynamic features that make the "post-combustion water injection" scheme potentially more attractive than in four-stroke engines.

Advantages of the two-stroke long-stroke architecture

· Large time-volume for steam expansion.
Two-stroke diesel engines typically have a longer piston stroke than four-stroke engines of similar power. After combustion ends, the piston continues to travel a considerable distance toward bottom dead center, and when water is injected during this period, the steam has time to expand, performing useful work. The longer the stroke, the greater the potential work of the steam at a given injection pressure.
· Organization of gas exchange.
In a two-stroke engine, scavenging occurs through ports in the cylinder. If water is injected after the exhaust ports close (or between the exhaust closing and the scavenging ports opening), steam is not released into the exhaust system prematurely. This simplifies control of the steam stroke phase.
· Thermal mode and cooling.
Long-stroke diesel engines have a larger combustion chamber surface area (per unit volume), which facilitates more intensive heat transfer from the metal to the injected water. The water evaporates, removing heat from the walls, piston, and cylinder head, reducing their thermal stress. This is especially valuable for two-stroke engines, where the piston and cylinder operate under harsher thermal conditions due to the lack of separate intake and exhaust strokes.
· Simplification of the injection system.
Large two-stroke diesel engines often use a low-speed mode, which allows more time for additional water injection. A separate injector or one integrated with the fuel injector can be used, without placing extreme demands on response time.

Potential Challenges

· Risk of steam condensation on cold walls.
Long-stroke two-stroke engines have a significant liner surface area, which, if not preheated sufficiently, can condense steam, reducing efficiency and degrading lubrication. This requires careful monitoring of coolant temperature and possibly preheating before starting.
· Increased load on the cooling system and oil.
Some of the heat previously dissipated through the radiator is now converted into steam and released with the exhaust gases. This reduces the thermal load on the components, but requires increased scavenging system performance and can alter the turbocharger's temperature profile (if the steam is not separated before the turbine).

Efficiency mark

Existing research (including patents and experimental work on six-stroke and combined cycles) shows that two-stroke long-stroke diesel engines have the greatest potential for implementing steam expansion:

· Literature (e.g., work on the Crower cycle, as well as studies for marine engines) notes that the increase in indicated efficiency can be 5–12% depending on the proportion of injected water, injection timing, and engine design.
· Long stroke reduces exhaust losses: steam expands to near atmospheric pressure before the exhaust valves open.
· Reducing the thermal stress of the piston group increases reliability and opens up the possibility of further boosting the engine's power (for example, by increasing the boost pressure).

Conclusion:
Post-combustion water injection to generate additional steam work is most effective in two-stroke diesel engines with a large piston stroke-to-diameter ratio. These engines provide the necessary time for efficient steam expansion and have sufficient surface area for heat transfer. With proper injection timing and the use of modern anti-corrosion protection methods (inhibitors, coatings), this technology can improve overall system efficiency and reduce the thermal load on components.
"

[Nemchinov Vl]

Since it is impossible to completely destroy Mother Nature by using the “peaceful atom” haphazardly, humanity, which is not capable of calculating its steps to at least three in advance (even in safety parameters and calculations of possible accidents), until he succeeded, he just won’t calm down.
Now, under the flags of "fighting for the environment" (like Christians once did, under the crosses... but with fire and sword !!! They went to cut the heretics and not properly believers...) decided to fill the seas with "time bombs" - a merchant fleet running on ammonia!!!
Take that Mother Nature,
I'll blow your guts out! You won't be able to resist!

[tralflot1832]

The International Maritime Organization, or IMO, is a specialized agency of the UN. (UN bureaucrats are fighting shipowners by promoting the "green agenda" wherever possible.) There's plenty of chaos there, and it can be a lot of fun. The baidanut "greens" are trying to seize the seas.

[ism_ek]

Ammonia is made from natural gas... Is it worth the trouble?

[Inj Meh]

Quote: ism_ek

Ammonia is made from natural gas... Is it worth the trouble?

This was originally intended as an alternative to hydrocarbons (nitrogen from air, hydrogen from water)

But naturally no one is banning gas (which Europe has “refused” or cannot obtain)

[drags33]

Looks like this hemorrhoid isn't worth the candle... ))))
Using ammonia, despite all the SIGNIFICANT disadvantages of its use, when conventional hydrocarbon fuel is available??? I see absolutely no reason to do so...

[Good Evil]

I don't understand the point of all this fuss either. The article talks a lot about the downsides of this engine, but what are the advantages? The sheer danger to people in the event of an accident outweighs all the advantages! And how many fish will it kill in the ocean! ) And alternative systems for storing and refilling ammonia in ports are also a real pain in the ass and won't bring peace of mind to those around.

[cpls22]

Quote: Good evil

The article talks quite a bit about the downsides of this engine, but what are the advantages?

Perhaps the problem is that those who don't master this complex technology will be cast as pariahs and barred from their "blooming garden." An attempt to make sea freight their own domain.

[Victor Leningradets]

And they're pushing this diesel again!
Anything, just to breed these monsters.
If you're looking for green energy, hydrogen generators are your next best bet. They offer higher efficiency, are environmentally friendly, and don't pose any energy conversion issues.

[Motorist]

Quote: Victor Leningradets

Anything, just to breed these monsters.

What has higher efficiency than an internal combustion engine? Is a hydrogen generator a heat engine? Please clarify.

[Victor Leningradets]

The efficiency of a hydrogen generator is the ratio of the electrical energy produced to the calorific value of the hydrogen used. Currently, it's 56%, and that's not the limit. Hydrogen production from water during periods of low electricity consumption using renewable sources is a less expensive process than ammonia synthesis. So diesel, with its toxic nitrogen oxide emissions, is out of the question.
Today there was a meeting on advanced engines for merchant and littoral fleets. These figures were discussed there.

[Sergey Aleksandrovich]

Before the construction of the Volga hydroelectric cascade, steam locomotives ran on dried vobla. Huge hangars stood with fish hanging in them. And you, you say, diesel engines...for the littoral fleet.

[Victor Leningradets]

It's not me saying this - it's the Ministry of Industry and Trade.
There was a meeting on engine building for the navy.
Priority areas:
- MOD for large-tonnage vessels;
- CCGT for Arctic gas carriers;
- multi-fuel for the littoral fleet;
- R&D on hydrogen energy.
Ammonia was mentioned as a fuel, as well as traditional fuels with an emphasis on ecology.

[Victor Leningradets]

Are the minus-takers angry that you're not invited to meetings?
There are no vacancies for the ignorant there.

[barbos]

R&D in hydrogen energy.

Before you even dream about hydrogen energy, ask the rocket scientists what kind of nasty thing your hydrogen is. From production, storage, to application. Despite all its obvious advantages, it was eventually abandoned in spaceflight. And quite a while ago, at that. Even though spaceflight is a far more science-intensive and advanced industry than the entire littoral fleet.

[Victor Leningradets]

I don't fantasize anything:
There's a shipbuilding meeting where things are proposed and added to the list of funded R&D projects. I'm working on other topics there. Hydrogen generators are operating quite successfully, including in China and Belarus, and if you look closely at the methods for producing and storing hydrogen, you'll see that it doesn't pose much of a threat compared to, say, methane.

[barbos]

Сейчас вам открою большой секрет красивых цифр КПД водородных элементов. Они крайне хороши, когда немного в стороне остаются потери, связанные с получением и хранением.
Сам по себе водород у нас не добывают в отличие от того же метана. Получают из воды гидролизом или из того же метана. Получать его кидая натрий в серную кислоту довольно опасно. Только сам процесс получения довольно энергозатратен. Молекулу воды не так просто расщепить, там прочные водородные связи и поэтому сам процесс не такой энергоэффективный как кажется. АЭС желательно иметь под боком для получения в огромных объёмах. Это первые довольно ощутимые потери на производство водорода.
На следующем этапе его надо отделить, почистить (у вас не всегда вода двойной дистилляции под рукой) и убрать в ёмкость для хранения. Как-то ради интереса смотрел цены на компрессоры для жидкого азота и кислорода. Ну не фантастика, но кусаются. Но зная примерно специфику водрода, понимаю, что будет намного дороже и сложнее.
Транспортировку и хранение сейчас не рассматриваю, но она будет разительно отличаться от той, что применяется к метану.
Итого мы имеет три основные проблемы, которые лежат только на этапе получения водорода:
1 Водоподготовка, если рассматривать вариант получения водорода гидролизом. Можно ли таким образом получать из метана, не знаю. Теоретически ограничений нет.
2 Сам процесс сепарации водорода из воды. А там крепкие ковалентные полярные связи.
3 Предварительная очистка и сжатие/сжижение водорода, которые совсем не подарочек для хранения по сравнению с тем же метаном, которым многие пользуются дома.
В итоге проще взять мощный источник протонов (голые ядра водорода) в хорошей оболочке биологической защиты из обеднённого урана, как это делают в РИТЭГ, из которого прямым преобразованием через люминисценцию гаммы (она там будет обязательно) можно извлекать дополнительную энергию.

[Victor Leningradets]

Спасибо, понял, что Вы - не чужой в стране Инженерии.
Тут вся штука в чём:
Всё затраты на получение водорода списываются в пропорции на возобновляемые источники. И если система получения водорода электролизом автономно замкнута скажем на ветряки или приливную электростанцию, то зачитываются только затраты энергии на изготовление и ремонт генерирующего оборудования. Китайцы этим пользуются по-полной.
В нашем случае технология получения водорода основана на использовании часов провала ГЭС в долях с Китаем.
Теперь про 56%:
Это именно потенциал полученного водорода с учётом дисконта хранения относительно выработанной на ЭЭГ электроэнергии.
В нашем случае предполагается тестирование генератора 200 кВт, установленного в дублирование к аварийному ДГ равной мощности. Если пройдёт удачно, будем думать об установке буксира и малого ледокола.
Настораживает, что за всём проектом торчат уши китайцев. У них любимый приём втюхать за долю за малую пробную серию, вытоптать конкурентов и наладить экспорт. Эти операции пользуются их господдержкой. Ну а наши чины рады стараться за соответствующее вознаграждение.

[barbos]

Ну вы частично сами нашли объяснения, указав по Ленински, кому это выгодно. Но у Китая нет развитой добычи углеводородов и в текущей мировой обстановке им надо как-то балансировать, чтобы не зависеть от одного поставщика.

Ну а наши чины рады стараться за соответствующее вознаграждение.

Впрочем, ничего нового (ц. из м/ф Винни Пух)

[Motorist]

You mean a hydrogen fuel cell? Well, if we can find a 15-megawatt unit... Or better yet, a coal-fired one. Then we can compare its efficiency to diesel, when the fuel is fossilized and fed to the furnace after simple and inexpensive fuel preparation.

Hydrogen isn't free, even during the low-energy hours you described. Incidentally, during those hours, thermal power plants with steam turbines emit profuse smoke. And at other times, too. Speaking of emissions.

[Victor Leningradets]

Hydrogen produced from renewable sources and nuclear power plants is eligible. There are commercially available 500 kW storage units, with a target of 5 MW, and then a multi-bank option. Lukashenko has ordered 60 BelAZ trucks with such units. There aren't many engineering challenges. It's all about economics. A preliminary feasibility study for such units as backups for ice-class LNG tankers will be reviewed in May. We'll see then.

[Motorist]

Quote: Victor Leningradets

Hydrogen produced from renewable sources and nuclear power plants is counted.

This is not fair! It's a scam! Stop these scammers! And the listed sources also have a significant carbon footprint.

Quote: Victor Leningradets

Lukashenko orders 60 BelAZ trucks

Even here we have a summons - what can you do...

Quote: Victor Leningradets

such installations as backup for ice-class gas tankers

What do you mean, instead of the emergency generator? I can believe they'll install it just for the sake of a subpoena. My emergency generator, if it burns 50 kg of fuel a month, has already done its job. But it won't be enough for propulsion and the power plant.

Why don't they want to use coal for fuel cells? Just kidding, I know it's weak.

[Victor Leningradets]

No decision has been made yet. The emergency generator will remain in place in any case. If they install one, it will be in parallel, as a pilot project. The developer swore that similar systems are already operating abroad as backup generators. So he promised some kind of feasibility study for such a setup, and then we'll see.

[Luminman]

Quote: Victor Leningradets

If you're into green energy, then next up are hydrogen generators.

High cost and safety issues negate all the good properties of this fuel...

[Victor Leningradets]

Apart from the cost, everything else is irrelevant.
Storage—whether in 700-bar cylinders, in liquefied form, or as hydrate films—is well-established. Accidents are virtually nonexistent. And the cost is offset by higher efficiency than any diesel engine, and, given the green agenda, by complete environmental neutrality.

[barbos]

Storage, both in 700 bar cylinders and in liquefied form

Storing hydrogen in any form is always associated with leakage, as its atoms easily and naturally leak through the reservoir's crystal lattice.

There are practically no accidents.

Simply because no one uses it.

The cost is offset by higher efficiency than any diesel engine, and, given the green agenda, by complete environmental neutrality.

In the late 1990s and early 2000s, automakers like BMW, Mercedes, and Audi toyed with hydrogen engines, but ultimately abandoned the idea, permanently. But in keeping with the good old, centuries-old tradition, our engineers don't care about global experience and always try to cobble together their own hacks.
And one more thing. Theoretically, taking into account all the thermal and mechanical losses (the laws of thermodynamics send their regards), you won't be able to achieve a full efficiency of more than 50%. Ask the rocket scientists what a miracle a hydrogen fuel pump is. Let your nerdy engineers put their incredible conceit to rest and turn to those with far more experience and knowledge in this matter.

[Victor Leningradets]

I want!
Arrogance is punishable. Thermal and mechanical losses are for thermal engines, not fuel cell generators. I read the state test report. It says 56%, but what about a combined cycle plant with 60% efficiency?
Well, no need to be rude:

Let your smart engineers put their incredible conceit aside and turn to those who have much more experience and knowledge in this matter.

If you are worth anything as an engineer, study the problem and then write.
P.S. I don't work in hydrogen energy myself. I work in energy and propulsion for ice-class vessels.

[barbos]

Самомнение - наказуемо

Потому что не совпадает с вашим?

ПГУ с КПД 60% как поглядит на Вас?

Фантастически. Где-то обязательно накрутили с цифрами. Даже на генераторы с топливными элементами как ни странно оказыают влияния электрические потери, которые обычно выделяются в виде излучения (теплового тоже). И если где-то есть резервуар с рабочим телом, то система автоматически подпадает под действие механики сред (газодинамики, гидродинамики), то бишь обрастает потерями родом из термодинамики. А там Второй закон термодинамики спросит по полной программе.

If you are worth anything as an engineer, study the problem and then write.

Руки уже подзажили, а так они видели щёлочь и кислоту аккумуляторную. Ну и с фундаментальными ограничениями физики на уровень энергии, которую можно извлечь из валентных электронов атомов (практически вся энергетика и механические системы кроме атомных) тоже знаком.

[Glenn]

I don't know about the environmental impact, but the costs will definitely skyrocket. From ammonia production to the complex and dangerous equipment on board.

[Dead duck]

Wouldn't it be easier to make normal, fuel-efficient engines?
And what's the total cost of the trip? Forget about the environment; it's even more harmful than diesel fuel.

[barbos]

Wouldn't it be easier to make normal, fuel-efficient engines?

The current internal combustion engine design is immoral and outdated, dating back about 50 years. Everything written here has been used in one way or another. But global industry is more than happy with it.

[Severok]

The commercial name for 316L steel is completely uninformative for materials science. 40x13, KhVG, R6AM5, 40ps are examples of normal alloy labeling. All Western-style commercial names are uninformative in terms of both the alloy's chemical composition and its physical properties. Consequently, commerce and capitalism are hindering human development. Regarding the use of ammonia as a fuel: there are too many hazards for both humans and the environment; it is technologically complex and energy inefficient;

[vitaliy20091959]

Machine operators are screwed if anything happens with such installations, and there are enough questions about technical safety for a couple of volumes

[Yuri_K_Msk]

Unlike natural gas, ammonia doesn't occur underground. The primary raw material for ammonia production is natural gas. The main steps are: Methane is converted into a mixture of hydrogen and carbon monoxide in the presence of steam, then the hydrogen is combined with atmospheric nitrogen over a catalyst to produce ammonia, and the carbon monoxide is oxidized to carbon dioxide, which is released into the atmosphere. All processes occur at temperatures of 500-700°C, pressures of up to 300 atm, and are highly energy-intensive. What's the point of using ammonia as a fuel if it's an order of magnitude more expensive than natural gas, not to mention fuel oil? Where's the money? It's simpler and cheaper to use LNG directly. Furthermore, ammonia dissolves readily in water, forming an alkali that kills everything. One accident, and far more animals will die than from fuel oil.

[Alexey Lantukh]

The main raw material for the production of ammonia is natural gas.

Ammonia can be extracted from the atmosphere and water using electricity, which is what green groups are interested in. However, this process, which already exists, is more expensive than using natural gas.

[kamakama]

"However, safe handling of ammonia on ships will require the installation of complex and expensive safety equipment (detectors, shut-off valves to isolate leaks, double-walled fuel systems, etc.), specially designed fuel equipment, etc.

The energy density per unit volume of ammonia (12,7 MJ/L) is lower than that of diesel fuel (35 MJ/L). Transporting the same amount of energy as diesel fuel would require approximately 2,8 times the volume if the ammonia tank were refrigerated.

All of this completely negates any economic rationale. The tank capacity is four times larger (including fuel equipment and double walls), and the hassle of refrigeration (which also needs power, meaning even a simple idle time in port will result in additional fuel consumption)—who needs all that?

[Alexey Lantukh]

Apparently, ammonia engines are only interesting because they're "green." That's all. And the green agenda is still controversial. In a few years, the temperature could drop like in the 40s, and then the greenhouse effect will be forgotten, just like ammonia engines.

[bar]

At the same time, there will be no serious bunkering problems for ammonia fuel, as it is produced worldwide and transported through most major ports.

Am I the only one who thought all this was crazy? Ammonia's calorific value is 5,2 kW/kg, while methane's is around 14 kW/kg. Not to mention that producing ammonia requires that same methane plus complex chemical processes. Meanwhile, ammonia itself is a valuable raw material for the defense industry and fertilizer production, while methane can be found right out of a hole in the ground in practically unlimited quantities.
If it's good for anything, it's only for gas tankers transporting, say, ammonia. But most of all, this looks like a cash grab under a green light.

[Kostadinov]

Apparently, ammonia engines are only interesting because they are "green".

Interest in ammonia primarily stems from its role as an alternative to oil and gas. The Germans considered it a possible alternative to oil during World War II.

[barbos]

While they're still trying to beat the dead horse of heat engines with their low efficiency, low power density, and mandatory moving parts, enthusiasts have taken a small amount of gamma radiation, surrounded it with a phosphor, and then installed conventional solar cells. They're currently working on increasing the efficiency of the luminescence and the cells.
There are no moving parts or thermal circuits. In terms of energy capabilities, gamma quantums are orders of magnitude greater than those of thermal electrons.

[stels_07]

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