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Why Injectors Fail: And How to Avoid It

  
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Why Injectors Fail: And How to Avoid It

 
jason.thompson jason.thompson
Guru | Posts: 839 | Joined: 06/08
Posted: 08/17/12
02:13 PM

Why Injectors Fail
And How to Avoid It  
By: Jason Thompson
Photos Courtesy of Afton Chemical and Exergy Performance

Pull Quote: In order to tell if there is a problem with common rail injection systems fueled with ULSD (ultra low sulfur diesel) fuel we need to know how many injectors have failed since its introduction.


Injectors fail because of two main reasons. The first has to do with the soundness of the mechanical structure of the injector and the second has to do with the quality of the fuel. In order to get an understanding of the workings of an injector and what actually makes them fail we contacted Exergy Engineering. They empowered us with images of failed injectors taken with a microscope and some information on how you can keep it happening to your diesel. In order to find out as much as we could about the fuel side of the equation we contacted Afton Chemical a company who specializes in fuel additives. Afton has 85 years worth of experience working with the OEMs and fuel companies. By leveraging both of these companies expertise we hope to make fuel injector problems a thing of the past.

1- Normal injector firings during lifetime and average lifetime

               Based on algorithm below, plug in the numbers for expected number of miles and number of injection events per engine cycle to get to number of firings in a lifetime.

   # miles /lifetime x  avg speed x 60min/hr x avg engine rpm x # injections per engine rev (2 stroke or 4 stroke) = Number of injections per lifetime

 Example – 140,000 miles/life x 1 hr/33 miles x 60min/hr x 1300 rev/minute x 2 injections/2 engine rev (pilot and main 4 stroke) = 330,000,000 injections /life  

             

Average life of various light duty Diesel Injection systems. Keep in mind this is “average” and each system has its own set of operating parameters such as number of injections per engine cycle, operating pressure, EGR or no EGR, and targeted emission standards. “Your results may vary”

5.9 and LB7 injectors – 140k

LBZ/LMM injectors – 175k (tougher inj but more injection events than 5.9/LB7)

HEUI injectors (7.3 pick-ups) 150k (single injection event, limited use of PRIME split injection device)

CP3 pumps – 200k

Older systems

12v/24v injectors – varies

VP44 pumps – 125k

Inline P and M Pumps – 175k

             
2- Normal Temp at nozzle – Max allowed 300 deg C (572F)

3- Sled Puller temp at Nozzle  - Less that 537 Deg C (1000 deg F) otherwise nozzle starts to soften (annealing point of typical Bosch nozzle material)  

4- Normal pressure at nozzle (peak firing pressure of cylinder and injection pressure)

Cylinder firing pressures – 16-18 Mpa (2300 to 2600 psi)
               
Injection pressures at nozzle – Common Rail systems 160 to 200 Mpa (23-29,000 psi) Older systems 80 to 100 Mpa (11-15,000 psi)
Note – Heavy Duty (Class 8 trucks for example) have been running injection pressures in excess of 30,000 psi for years using Unit Injector and Unit pump systems. Cost is not as great a problem as light duty and fuel economy is king.  

5 – Sled Puller pressure at nozzle (peak firing pressure of cylinder and injection pressure)

               Cylinder firing pressures – We have measured over 31Mpa (4500+ psi) in dyno testing
               Injection pressures at nozzle – Common Rail systems 180 to 220 Mpa (26-32,000 psi) Older systems unknown


Is There a Fuel Injector Problem?

If proper maintenance is performed and problematic practices avoided the vast majority of diesel owners will probably go thousands of trouble free miles without a problem. If you’re a diesel owner with an older engine (pre-common rail) most of this article (besides the general maintenance items for example changing your fuel filter regularly) doesn’t apply to you. This is because older diesel injection systems only use about a quarter of the pressure and much wider tolerances compared to new systems. Just think of your bathtub as an example. What clogs first the shower head or main spigot? In order to tell if there is a problem with common rail injection systems fueled with ULSD (ultra low sulfur diesel) fuel we need to know how many injectors have failed since its introduction. Right now this failure rate is unknown, but from anecdotal reports of failures we know there is always room for improvement.


Sidebar: 1

According to Exergy Engineering injectors fail because of five major reasons. We listed them here along with the indicators of the problem, the causes, and how it’s prevented.


Failure: High Internal Leakage Or Return Flow

Indicators:

1. Engine is hard to start (requires increased cranking time in order to start).
2. Low common rail pressure codes.

Causes:

1. Worn injector ball seat.
2. Leaking cross feed tubes (Cummins).
3. Blown internal high-pressure seal.
4. Incorrect nozzle needle clearance.
5. Cracked nozzle body
6. Cracked injector body

Prevention:

1. Keep fuel system clean, change fuel filters, purchase fuel from reliable sources, avoid filling from portable construction fuel tanks.
2. Avoid overly aggressive tuning that increases rail pressure and injector pulse widths and do not remove pressure limiting devices from the system.
3. Do not use remanufactured or aftermarket components that are not properly designed or manufactured.
4. Metallic burrs have no place on any fuel system component and reject any component that has them.
5. Use only Bosch nozzles as they have superior crack resistance. No other aftermarket nozzle comes close.
6. Do not mix nozzle needles because they are matched to the body and moving one from another can result in excessive clearance and or improper needle fit.


Failure: No Injection

Indicators:
1. Balance rates are high (positive) indicating that fuel is being added to the cylinder because the computer thinks the fuel injector is not flowing enough. The computer makes this decision based on the two things it knows; the rotational speed of the crankshaft and the amount of fuel delivered. If the crankshaft is not spinning as fast as the computer thinks it should or is spinning faster than it should fuel is added or taken away to create balance. Loss of cylinder compression is also possible with a high (positive) rate.  
2. Cylinder contribution low (cylinder contribution test is performed by shutting off one injector at a time while taking note of drop in engine RPM)
3. ECU fault codes

Causes:
1. Debris or rust in the injector plugging the nozzle.
2. Armature and or nozzle needle stuck
3. Bad stator (rare)

Prevention:

1. Keep fuel system clean, change filters, purchase fuel from reliable sources, and avoid filling from portable construction fuel tanks or questionable sources.
2. Do not use remanufactured or aftermarket components that are not properly designed or manufactured.
3. Metallic burrs have no place on any fuel system component and reject any component that has them.
4. Avoid tying the returns from multiple high pressure pump kits and injectors to a single return line. Excessive return pressure acting on the injector stators can lift them (and in extreme cases blow them off) shutting the injector down.
5. If a long storage time of the vehicle is expected arrange to have it started on occasion to prevent internal varnishing and corrosion of internal components. Aftermarket fuel additives specifically designed for stabilizing diesel fuel should also be added.

Failure: Excessive Injection

Indicators:
1. Excessive smoke at idle, poor running, and banging
2. Balance rates high (negative) indicating the computer is removing fuel from the injector.
3. Cylinder contribution test is high meaning as each injector is activated one will increase engine RPM more than normal.
4. High exhaust gas temperatures.
5. Engine damage from excessive heat or hydraulic lock from excessive fuel in the cylinder.

Causes:

1. Worn ball seat in injector or poor end of injection cut off.
2. Nozzle needle seat worn or damaged.
3. Debris in control system of injector, which holds it open.
4. Debris in nozzle needle seat holding it open.
5. Cracked nozzle.

Prevention:

1. Replace worn and high mileage injectors. Do not use these injectors as a foundation for building a high output injector set.
2. Replace worn nozzles.
3. Keep fuel system clean, change filters, purchase fuel from reliable sources, and avoid filling from portable construction fuel tanks or questionable sources.
4. Metallic burrs have no place on any fuel system component and reject any component that has them.
5. Do not use remanufactured or aftermarket components that are not properly designed or manufactured.


Failure: Incorrect Injection Timing and Duration

Indicators:

1. Rough running, poor cylinder balance, and knocking.
2. Piston damage.
3. Large cylinder to cylinder exhaust temperature variation.

Causes:

1. Ball seat wear.
2. Incorrect injector assembly, parts mixed, or parts missing.
3. Injector needle lift increased to increase output.

Prevention:
1. Replace worn injectors.
2. Assure injectors are serviced or purchased from a reliable source.

Failure: Incorrect Injection Rate

Indicators:

1. Rough running and poor cylinder balance.
2. Large cylinder to cylinder exhaust temperature variation.

Causes:

1. Poor nozzle flow balance.
2. Nozzle needle lift incorrect (mixed or missing parts).
3. Partially plugged nozzle.
4. Wire brushed nozzles.

Prevention:

1. Keep fuel system clean, change filters, purchase fuel from reliable sources, and avoid filling from portable construction fuel tanks or questionable sources.
2. Metallic burrs have no place on any fuel system component and reject any component that has them.
3. Do not use remanufactured or aftermarket components that are not properly designed or manufactured.
4. Assure injectors are serviced or purchased from a reliable source.
5. Do not clean nozzles with a wire brush.

Sidebar 2:

Afton Chemical’s North American Marketing Manager David Cleaver responds to our question “Why Do Injectors Fail?”

There are two major causes of injector failure associated with the properties of the fuel itself: excess wear and deposits.

Excess Wear

One mode of injector failure is excess wear. Prior to 2006, diesel fuels in the United States contained relatively high amounts of sulfur. This sulfur comes from the crude oil refined into the fuel. This sulfur in the fuel acted as a natural lubricant for the fuel system. Ultra Low Sulfur Diesel (ULSD) was gradually introduced into the market and is now mandated in all diesel fuel segments including on-highway, off-highway, and railroad. ULSD has a maximum allowable sulfur content of 15 ppm. As refiners removed this sulfur the lubrication benefits went away as well. As a result additives are now used to restore lubricity. The standard for measuring this lubricity is the High Frequency Reciprocating Rig (HFRR) Test, ASTM D-6079, which measures the size of a wear scar between two metal surfaces lubricated with the fuel. The less lubrication the fuel provides, the larger the wear scar. The maximum allowable wear scar in the United States is 520 microns (460 microns in Canada). Many fuel distributors add additional lubricity improvers to the fuel to limit premature wear.

Abrasion

While fuel lubricity is an important factor in determining the wear characteristics of the fuel injection system, it is not the only fuel-related cause of excess wear. The other potential cause of premature injector failure due to wear is caused by abrasion.  All fuels contain small amounts of impurities, even the highest quality diesel fuels. Some of these impurities include very small (a few microns in size) particles that can pass through even the tightest on-board vehicle filters. If the fuel contains a large amount of these small insoluble particles, over time they can abrade the injectors as they pass through them during normal engine operation. In extreme cases, this abrasion can significantly alter the fuel spray pattern, causing reduced engine performance, and even increased downtime and maintenance due to severe abrasion. Good housekeeping practices by the fuel supplier, and good fuel filtration can reduce the damage caused by this abrasion.

Deposits

While excess wear, whether caused by poor fuel lubricity or abrasion, is important to consider when discussing the cause of injector failure, the major reason for injector failure today is due to excessive buildup of deposits. There are two major types of deposits: external injector deposits and internal injector deposits. External injector deposits generally are caused by incompletely burned fuel that builds up around the injector holes. These deposits are referred to as coking deposits. While in most cases these deposits may not lead to injector failure, they can build up enough to disrupt the fuel spray, which leads to less efficient fuel combustion. This is often observed by the vehicle operator as a noticeable loss in power or lost fuel economy. Detergent additives have been used quite successfully to help control these external deposits, and restore the injector to its most efficient performance; restoring both the lost power and lost fuel economy caused by the buildup of these external deposits.

Internal Diesel Injector Deposits (IDID)

In the last 5 years, a new type of injector deposit has begun to appear. This deposit does not form on the external tips of the injectors, but rather on the internal parts like the injector needles and pilot valves. These deposits often look similar to the coking deposits (dark brown in color), but also can be very light, almost grayish to off-white in appearance. While they can form in virtually any type of diesel engine, they typically only cause operational issues in the newer engines with highly engineered injection systems.  

Engine manufacturers are now offering injection systems that operate at very high injection pressures (greater than 30,000 psi in some cases) that supply fuel to all injectors through a common fuel rail. These engines are often referred to as High Pressure Common Rail (HPCR) engines. They were designed to help meet the ever-tightening emission regulations engine manufacturers must meet. The extremely high injection pressures create a very fine fuel mist spray in the combustion chamber, resulting in more complete burning of the fuel. This more complete fuel burning yields lower emissions and can also improve fuel economy.
In order to maintain these high injection pressures, the injector assemblies have been highly engineered, and have very tight clearance tolerances, sometimes as small as 1 – 3 microns (a human hair is typically 70 – 100 microns thick). So, you can imagine that it would not take much material depositing on these parts to cause poor injector needle actuation, leading to poor engine performance. In extreme cases, these deposits can lead to complete sticking or seizing of the injector needles, particularly after the vehicle has been shut down and the engine has been allowed to cool.  

As these internal deposits build up, they can cause the same symptoms as the more traditional external coking deposits, namely lost power and reduced fuel economy.  In extreme cases where the injectors begin to completely stick, they can lead to excessive vehicle downtime and high maintenance costs.

Q: What are the sources of the internal deposits?

A: Through cooperation with engine and vehicle manufacturers, Afton
Chemical has performed extensive engine testing and chemical analysis of field deposits from all over the world. Using sophisticated analytical chemistry techniques, two categories of deposits have been identified to
date: 1) carboxylate salts, sometimes referred to as waxy deposits or salt deposits and 2) organic amides, sometimes referred to as polymeric or lacquer deposits.

The carboxylate salt deposits are formed from the reaction of sodium ions with carboxylic acids. Sodium ions can come from the base fuel or additives put into the base fuel. For example, in certain areas of the world, sodium nitrite corrosion inhibitor may be used for pipeline corrosion protection. One way to avoid the formation of these salts is to limit the amount of sodium in the diesel fuel.
There are various sources of the carboxylic acids. Afton has concluded that DDS (dodecenyl succinic) acid and HDS (hexadecenyl succinic) acid corrosion inhibitors are the primary sources of the salt deposits found in the U.S. and some parts of Europe. A detailed summary of the investigation that led to this conclusion can be found in SAE Paper 2010- 01-2242 published by SAE International TM. Afton has also concluded that sodium hydroxide, an aggressive caustic (basic) chemical present within the sodium nitrite corrosion inhibitor, will degrade lubricity improvers, biodiesel and some PIBSI- type detergent additives to form other carboxylate salts.

The source of the second type of internal deposit, organic amide, has been much more difficult to identify. Using chemical analysis and engine testing, Afton has concluded that these deposits are formed from low molecular weight, polar materials found as contaminants (production
by-products) in some diesel PIBSI-type detergent additives. Afton has been successful duplicating the organic amide deposit chemistry and diesel injector sticking on an engine test when these contaminants are added to the test fuel.  
___

My personal goals include developing perpetual motion and bringing power to the people. I’m also working on building a ’87 Ford F-250 7.3L IDI (Project 300) on a paycheck- to-paycheck budget. One day, I’d like it to be a renewable diesel-steam-hydraulic-compressed- air-wind-solar-infinitely-variable-transmission-equipped hybrid, but until then, I’m just happy to have a simple diesel-powered pickup.

jason.thompson@sorc.com

5toMidnight 5toMidnight
User | Posts: 167 | Joined: 03/12
Posted: 08/19/12
05:15 AM

This article is complete bÚll §h¡t, intended to scare people into buying useless fuel additives that his company sells.

ULSD does NOT have any lubricity problem. It has been around since 2006. If there were any problems then older diesels would have been dying by the tens of thousands within a year.

After 6 years there has been zero ULSD related issues. People claiming it as cause for failure of an injector or pump are only using it as a scapegoat because they don't know how to properly diagnose an engine.


I have put over 100,000 miles on my 30 year old personal vehicles since 2005 with zero injection pump or injector issues. Using plain diesel fuel, NO ADDITIVES. If ULSD is such a danger, why are my 30 year old diesels still running perfectly?  

MarineOne MarineOne
Addict | Posts: 2039 | Joined: 10/08
Posted: 08/20/12
04:16 AM

If you read the entire article .......


Icon Quote:
Is There a Fuel Injector Problem?

If proper maintenance is performed and problematic practices avoided the vast majority of diesel owners will probably go thousands of trouble free miles without a problem. If you’re a diesel owner with an older engine (pre-common rail) most of this article (besides the general maintenance items for example changing your fuel filter regularly) doesn’t apply to you. This is because older diesel injection systems only use about a quarter of the pressure and much wider tolerances compared to new systems. Just think of your bathtub as an example. What clogs first the shower head or main spigot? In order to tell if there is a problem with common rail injection systems fueled with ULSD (ultra low sulfur diesel) fuel we need to know how many injectors have failed since its introduction. Right now this failure rate is unknown, but from anecdotal reports of failures we know there is always room for improvement.








-Kris  

2006 Dodge Ram 2500 QC 5.9L - Smarty CR S-06 on SW #5

2008 Dodge Ram 3500 QC 6.7L - H&S MiniMaxx on DPF tune for towing
Titan Fuel Tank
Aero Muffler 4040XL
Nathan AirChime K3LA

5toMidnight 5toMidnight
User | Posts: 167 | Joined: 03/12
Posted: 08/20/12
05:27 AM

If you actually had any diesel experience.....


All common rail injectors are designed to be used with ULSD. Engineers are not idiots, the change to ULSD in 2006 was planned almost a decade in advance and they had ample time to design them for it.  

Mike McGlothlin Mike McGlothlin
Moderator | Posts: 1007 | Joined: 06/08
Posted: 08/20/12
04:36 PM

Just so you know, arguments and useless posts in this thread will be deleted. Jason posted this information here for a reason: it's chock full of great info, collected over several years by some VERY credible sources. The approximate/average life of each engines injectors and injection pump is extremely valuable, too, in my book.  
Mike McGlothlin

jason.thompson jason.thompson
Guru | Posts: 839 | Joined: 06/08
Posted: 08/20/12
05:50 PM

It's OK we need thick skin. 5toMidnight I like your posts on my thread they have lots of energy and you're not afraid to let people know what your thinking. You give it a real real factor. You're right we don't want articles that aren't a win-win-win. That is it benefits the Reader, Advertiser, Diesel Power (in that order otherwise it doesn't work for anyone). In this story's case neither company discussed advertises with us but that shouldn't even matter if the content is good. Diesel Power sometimes does its own research but other times we interview the researchers.

One time I interviewed Eddie Sturman the NASA Hall of Fame-rocket scientist-digital valve inventor who's design is found in the 6.0L and DT466 diesels. He said he got a call from a famous diesel company who he had never heard of and was asked to make an injection system. He saw the spec they needed and he was shocked. He said fuel injection is way harder than rocket science. He didn't have diesel experience but was able to bring something to the table. I have nothing but respect for any person who has created or helped to create a diesel fuel injection system. Same thing goes for pipeline workers and people who refine fuel. The undertaking of just moving that much liquid each day takes my breathe away. Sure I wish they would move faster towards renewables but I know it'll take their power to get that eternal energy security job done. Turning our waste and sunlight into liquid fuels. . I don't think they are idiots at all...but that is all besides the point...

Fact: ULSD has lubricity improvers in it from the refinery. The fuel and the ways and locations its extracted, processed, and transported is dynamic and varies from location to location and is constantly evolving.

http://www.theoildrum.com/

So what evidence besides your own trucks making it can you bring to the table? I'm not saying you're wrong I just need proof. I can't believe there is no fuel injector problem without evidence saying its OK when I hear of people having failures.

It all depends on the Principle of Good Enough defined by Wikipedia:

"The principle of good enough (sometimes abbreviated to POGE) is a rule for software and systems design. It favours quick-and-simple (but potentially extensible) designs over elaborate systems designed by committees. Once the quick-and-simple design is deployed, it can then evolve as needed, driven by user requirements. Ethernet[citation needed], the Internet protocol[citation needed] and the World Wide Web[citation needed] are good examples of this kind of design.

This kind of design is not appropriate in systems where it is not possible to evolve the system over time, or where the full functionality is required from the start.

Quantitatively, some measure of "good enough" may be assessed by establishing both a metric and a metric cutoff (or tolerance) of one previous iteration of a design and the current one; when the metrics converge to or below the cutoff, then the specification has been satisfied."  

Is diesel today good enough...not close? Should we be satisfied...Rudolf wouldn't be? Saying OK perfection is now would make my job (getting to the bottom of my readers problems) easy. Next article, "Everything is Fine Don't Worry." Although I get a pay check I'm mostly doing this because its funner, pays better or is way less monotonous compared to other jobs I've had (farm worker, Hardware department employee, household and heavy equipment mover, assistant superintendent at Oak Summit Golf Course, autobody work (at two different shops not including my Grandpas lessons who owned a body shop but didn't want me to do it because of the fumes but I couldn't stay away), oil changer, college history student, teacher (got fired for giving everyone A's), third world traveler (Inner and Outer Mongolia, China, North and South Korea, Bangladesh, Mexico, and Nepal) and diesel tech student (1 month) or could ever imagine having. I've been writing articles in Diesel Power for four years and in the meantime been talking to the best diesel mechanics, engineers, businessmen, industry lobbyists and end users in the country. Together this is some diesel experience but I'll be the first to admit that I don't know anything yet.  

I don't think you took issue with the mechanical failure side of the story (that I included so it wouldn't just be a one sided fuel derailing fest). I figured you'd like that part since it at least gives people who didn't already know a start on how to "properly diagnose an engine"  (since you didn't mention it) so they could be warned about a possible false flag failure. So I'll focus on the part you took issue with the fuel side:

I contacted Afton out of the blue because they are the biggest and would have the deepest pockets to find out about the alleged fuel problem. Who else could test fuel sources from all over the world and put out SAE papers about them (OK there are a few others but I contacted them too)? They also are in direct contact with the OEMs. They used to be an OEM back in the GM/Ethyl Corp days. I don't even think consumers like us can buy its products? They sell to fleets and oil refineries...I think.  I wasn't saying this is all 100 percent the way it is just wanted to introduce its SAE paper and what they think the problem is. Did you read the SAE paper maybe you could argue with its findings? I'm just introducing the subject.    

From here we'll find out what others have to say. But without scratching the surface how will we find out what's underneath. Even if there is nothing at least we know.

Mike's recent article on the pipeline foreman's truck who had fuel related problems is reason enough for me to put forth the energy and investigate.

How many injectors have to die before there is a problem? At this point we don't even know how many have failed?

Plus I wrote this article to the future diesel owners who'll have injection systems with even higher pressures and more sensitive to contaminants. Maybe we'll have to fuel our diesels with white gloves not to protect our hands but to protect our fuel systems?

We appreciate everyone's opinion but we also need constructive evidence to figure this thing out. We're all on the same team here and as Red Green says: On behalf of myself and Harold and the whole gang up here at Possum Lodge, keep your stick on the ice. I think I got my editorial for this month written...  
___

My personal goals include developing perpetual motion and bringing power to the people. I’m also working on building a ’87 Ford F-250 7.3L IDI (Project 300) on a paycheck- to-paycheck budget. One day, I’d like it to be a renewable diesel-steam-hydraulic-compressed- air-wind-solar-infinitely-variable-transmission-equipped hybrid, but until then, I’m just happy to have a simple diesel-powered pickup.

jason.thompson@sorc.com

5toMidnight 5toMidnight
User | Posts: 167 | Joined: 03/12
Posted: 08/21/12
05:30 AM

"How many injectors have to die before there is a problem?"
None, because there is no problem.

If you want cleaner fuel, great, add an ultra-fine bypass filter to polish the fuel. Every engine will benefit from that.
But, lubricity is NOT an issue even with ULSD.

Remember that in 1992 the EXACT same lubrication argument was attempted by many people, all of whom were either selling additives or people that believed the people selling additives.

Guess what happened? All the engines kept humming along nicely without any problems.
Same thing happened to those same engines 14 years later in 2006.

Rudolf means jack scheisse to diesels today. His original engine was designed to run on coal dust. "Diesel fuel" didn't even exist until years after he died.  

jason.thompson jason.thompson
Guru | Posts: 839 | Joined: 06/08
Posted: 08/21/12
09:57 AM

What happens if the (reported) salts in the fuel dissolve, go through the finest 1 micron filter, and then reform inside the passages of the injector (because of the pressure) causing it to stick intermittently?  

My main issue is not lubricity. It is sticky injectors. ULSD meets the required lubricity spec so I don't have an issue with lubricity.

We could also make the injection systems better by being able to monitor the fuel and if too much is going to a run away injector that injector should be turned off automatically.

http://www.dieselpowermag.com/tech/1007dp_10_things_you_didnt_know_about_diesel/viewall.html

Diesel first wanted to compress ammonia in a closed system like in a refrigeration cycle. Then he tried benzene (gasoline) in his first prototype and it blew up and almost killed him. Then he switched to liquid fuel which existed but of course wasn't called Diesel fuel until later.  
___

My personal goals include developing perpetual motion and bringing power to the people. I’m also working on building a ’87 Ford F-250 7.3L IDI (Project 300) on a paycheck- to-paycheck budget. One day, I’d like it to be a renewable diesel-steam-hydraulic-compressed- air-wind-solar-infinitely-variable-transmission-equipped hybrid, but until then, I’m just happy to have a simple diesel-powered pickup.

jason.thompson@sorc.com

jason.thompson jason.thompson
Guru | Posts: 839 | Joined: 06/08
Posted: 09/25/12
08:47 AM

Dear Mr Thompson,

Diesel states very clearly in his own book, Die Entstehung des
Dieselmotors (The Development of the Diesel Engine) (Springer, Berlin,
1913) that he primarily intended to develop his engine for liquid fuels.
The first fuel he had in mind was crude oil from Pechelbronn in Alsace,
but this proved to be too viscous for experimentation, so that primary
experiments were carried out using gasoline first, then Russian and
American lamp petrol (kerosene / paraffin). Especially during the
development of the injector nozzles, Diesel also made successful tests
with different gases, but later on concentrated on liquid fuels.

After the engine was running reliably, many more experiments were
carried out; among these in 1897 a systematic comparison of different
fuels (petroleum oils from different places and varying from very light
oils (ligroin) to heavy fuel oils, creosotes, spirits and shale oils).
Successful tests with peanut oil were also made, but later, for the
Paris exhibition in 1900.

Coal dust was not really considered worthwhile by Diesel, and the test
engines were built for liquid fuels only. A coal dust firing would have
required a somewhat different construction of the engine, with a
combustion chamber that is located adjacent to the cylinder. However,
Diesel made some preliminary testing with coal dust that were possible
with only minor modifications to the existing engine, i.e. he had the
motor start on lamp petrol and then added coal dust to the air flow.
This resulted in more than 60 % of the power output being generated by
coal combustion, the rest by petrol combustion. During the tests, the
piston was entirely covered by coal dust every few minutes and had to be
cleaned, so that Diesel did not pursue the topic any further.

To sum this up, Diesel tested his engine with about any liquid fuel he
could lay his hands on. In his book, Diesel uses lamp petrol as standard
to compare the other fuels to, but the design goal was clearly to have
an engine for any oil. I hope I could answer your question, but if you
have any more questions, don't hesitate to contact me.

Best regards,
Thomas Röber

Thomas Röber
Abteilungsleiter
Kraftmaschinen
Agrar- und Lebensmitteltechnik

Deutsches Museum
Museumsinsel 1
80538 München  
___

My personal goals include developing perpetual motion and bringing power to the people. I’m also working on building a ’87 Ford F-250 7.3L IDI (Project 300) on a paycheck- to-paycheck budget. One day, I’d like it to be a renewable diesel-steam-hydraulic-compressed- air-wind-solar-infinitely-variable-transmission-equipped hybrid, but until then, I’m just happy to have a simple diesel-powered pickup.

jason.thompson@sorc.com