The diesel engine was, like many things, born of necessity. The main engine types of the day—hot bulb oil, steam, coal gas, and gasoline—were not so thermally efficient or ideal for doing heavy-duty work like driving large-scale electrical generators. But how did the diesel engine come about? Settle in and watch the 1952 documentary “The Diesel Story“, produced by Shell Oil.
The diesel engine is founded on the principle of internal combustion. Throughout the Industrial Age, technology was developing at breakneck pace. While steam power was a great boon to many burgeoning industries, engineers wanted to get away from using boilers. The atmospheric gas engine fit the bill, but it simply wasn’t powerful enough to replace the steam engine.
By 1877, [Nikolaus Otto] had completed work on his coal gas engine built on four-stroke theory. This was the first really useful internal combustion engine and the precursor of modern four-stroke engines. It was eventually adapted for transportation with gasoline fuel. In 1890, the hot bulb oil engine was developed under the name Hornsby-Akroyd and primarily used in stationary power plants. Their flywheels had to be started manually, but once the engine was going, the bulb that drove combustion required no further heating.
By the turn of the 19th century, many engines of the four main types were humming along. But as we said, none were very thermally efficient. As respected as the steam engine was, the Shell Oil company will have you know that its thermal efficiency is the lowest of the low at 6%. Surely there must be a better way of doing work.
[Rudolph Diesel] was well determined to make it happen, and he worked under a set of four personal certainties: get away from steam, engineer combustion to occur inside the cylinder, use pure air, and ensure that air is highly compressed. With the fire piston’s basic design in mind, he went to work creating a combustion engine using ordinary air.
His first prototype didn’t work very well because of the pressure required, so he added an air pump to forcefully push the fuel into the cylinder. This is known as air-blast injection. By 1897, he had perfected his combustion method to the tune of 27% thermal efficiency.
Soon, diesel engines were being manufactured in many countries for use in electrical generation. Engineers realized their potential to do work at sea, and in 1912, the first diesel ship set sail from Copenhagen to Bangkok. The surge in seagoing diesel engines was the result of adapting the design for a two-stroke cycle, which provides more power.
Not all applications call for high power, however. Submarines, trucks, and tractors need high-speed engines, but the air-blast injection method proved inefficient. It was replaced by the jerk type pump, which sends an exact amount of fuel to the cylinder in a high pressure mist. Combustion was revolutionized once again.
http://www.youtube.com/watch?v=U7CxoJhjHR4
Retrotechtacular is a weekly column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.
Aren’t Sterling engines far more efficient than Diesels? Even back when this film was made?
As for practical uses of Sterlings… I believe the Danish navy uses them in submarines…
Sterlings are more efficient, but theoretically very troublesome in larger sizes, and requires very good heat management. It not only needs to heat the medium, but also cool it again, as it is a closed loop, with the combustion occurring externally, heating the medium through the casing at one end. With an internal combustion engine, the cold medium enters from the outside, and while there is an inefficiency in the engine heating the air, it is only a problem right up until combustion, where the air is replaced.
They also generally have poor power density (low power for their relative size) and have a host of requirements that make them more costly to build such as sealed crankcases (for designs with better power density) and piston seals that can handle high temperatures; depending on the type of sterling engine.
A well engineered sterling can be very efficient, but also very costly.
It’s also difficult and slow to throttle a stirling engine. It requires a certain heat gradient to work optimally, but if you turn down the heat source then the gradient drops because the engine is trying to put out more power than you’re giving it, so the efficiency falls drastically at partial load and most probably the engine will stall.
So, in order to throttle it you actually have to alter the compression/expansion volumes and the density of the working fluid (gas) while simultaneously adjusting the heating and cooling to match. It’s a rather tricky affair to get running properly.
And without a proper “recuperator”, or a heat storage exchanger between the hot and cold sides of the cycle, it too is barely more efficient than the 6% steam engine. The recuperator reduces the amount of heat that has to be dumped to make the gas expand or contract. The ASE project back in the 50’s or 60’s managed to make an automotive stirling engine that could be started in 60 seconds to adequate power output, but they never figured out a design for the recuperator that could be readily and cheaply mass-manufactured.
Stirling
It’s not just the Danish. The Swedes and Japanese also use them. It’s part of their Air Independent Propulsion systems.
One of the unmentioned advantages is that the diesel engine relies on the spontaneous ignition of the air-fuel mixture by means of cylinder compression. This implies that you can burn any fuel as long you compress it to its ignition temperature.
Italian FIAT had in the second world war a car prototype that would burn anything! From kerosene to whale oil. They would just mechanically adjust the cylinder volume to the right compression/volume ratio. Lots of leaks… (Although a camera with a dual cylinder on both tops would probably solve the problem…
Mr Diesel envisioned a world where the farmer would grow beside is common crops, oily seeds from which vegetable oil would be extracted and used to power the tractors and farm machinery.
But low grade oil was plentiful and vegetable oil never took its place in the farm.
Farmers today depend on state subsidies to have cheap diesel to power its machines…
When will the original dream of Mr Diesel be achieved??
If you use an older diesel engine, you can still run it off just about anything within a ballpark of the ignition pressure it was designed for. Hell, some run off used frying oil.
It does, however, have some consequences. It is not always as clean (Ironic, isn’t it?), and doesn’t always have as good lubricating properties (diesel does not only act as fuel, but also as a lubricant for the fuel delivery system). I’m not saying it cannot be build, but a simple change of compression might not be enough without then relying on a separate lubrication system, as well as regular cleaning of combustion chamber and fuel deliver system, depending on your fuel of choice.
Agreed, I’m aware of many people using frying, vegetable or crude oil to power older diesels that don’t have the critical tolerances and requirements of today’s fuel injection.
I think that generally part of the problem is the slower burn rate of those alternative fuels, leading to some of the emissions problems. The biggest challenge is filtering waste fluids to keep foreign material out of the pump and injectors.
Another problem with “alternate” fuels can be low temperature gelling. A number of vegetable oils will solidify when they get cold. Last winter I showed my wife a couple of containers with gelled contents from our garage. One was olive oil, and the other was a parafin based lamp oil.
I live in the southern part of the US, where folks aren’t used to cold. Last winter it got so cold a few times that they had to cancel school because bus’s had their fuel goop up in the tanks.
Two days later it was 40 degrees F like nothing had happened.
I work in a kitchen where we sell our used fryer oil to a farmer, spoke to him once, he uses it in a 3 year old tractor with an adapted engine management unit and “high flow” injectors which just so happen to feed the fryer oil quite nicely.
From What I understand, vegetable oil is a better lubricant than diesel. That’s why they add sulpher to diesel which is now being reduced by the EPA.
The main issue with vegetable oil and bio-diesels above 20% is jelling at low temperatures.
Sulfur is not added to diesel.
It’s naturally occurring in the crude oil used to create diesel.
Fuel gelling also occurs with regular diesel, though at temperatures much lower than vegetable oils. This is overcome with chemical additives or heating elements in the tank.
Ethanol gets added. Somehow it causes the fuel to release sulfur in about 6 months to a year. This can make engines which have stood for a long while to not start, but adding some fresh fuel into e.g. the fuel injector makes it work again.
Biodiesel is vegetable oil treated with methanol and lye (much of the methanol can be recovered to use again) to remove the glycerin. The glycerin is what gels at low temperatures. Biodiesel is better lubricating than regular diesel and it’ll clean gunk out of the fuel system.
The glycerin can be used to make some very nice soap, or things that go kaboom.
If you get to making too much biodiesel, some States will expect you to pay the per gallon tax on it.
I’m not aware of many subsidies for off-highway diesel fuel in the US. It’s just cheaper because a road tax is not applied to it. Granted, it’d be helpful to know if we’re on the same page concerning the country in question. :)
In some ways, you can consider not charging something on tax a subsidy in and of itself. I can either hand you $100 extra per year, or I can promise you that you’ll have to spend $100 less on your taxes at the end of the year. But the net result is the same is it not?
Not really, especially when the tax off-highway is avoiding is the road tax, used to maintain and build roadways that on-highway equipment puts wear and tear on. Yes, farm equipment does road from field to field using roadways, but it’s not an appreciable amount and they don’t cause as much wear as trucks thanks to their lower ground pressure.
The off-highway fuel is also not aimed solely at farm use as any diesel equipment not considered for on-highway use may use the fuel. Forestry, construction, home generators, farm equipment, mowers and landscaping equipment… that’s a lot of sectors while a subsidy typically targets just one.
Here in the UK we add a red dye to the reduced tax fuel (it is still taxed, we actually pay road tax seperately to the fuel, there are genuine fuel taxes in britain and currently we pay around £1.30 per litre of bog standard 95RON unleaded petrol/gasoline).
http://en.wikipedia.org/wiki/Fuel_dyes#United_Kingdom
I’ve never heard of roadside checks for diesel fuels outside of cars that have already been pulled over for some other reason though, contrary to wikipedia.
In the UK here too (glasgow) cars get dipped all the time for fuel. VOSA set up a road block type thing and every diesel (usually vans and taxis) is pulled over to test for cherry (red diesel) cherry thats had the dye removed, and used engine oil, which disguises the red diesel. I have been pulled in my recovery truck and dipped, never in a car tho i have seen/ heard it being done.
Same here in the US, off-highway is dyed red and will typically stain a fuel tank for a good period of time. I’ve heard of State Troopers checking for dye at farm auctions and other similar events… guess who’s most prone to using off-highway fuel in their on-highway trucks? ;)
“…so the farmer would have had to spend a great deal of their land resources and income just to fuel their own tractors.” Don’t those who use that statement consider the fact that when draft animals where the sole source of power farmers did spend a great deal of their land resources and income to fuel the draft animals? You can shed a tractor without it consuming fuel, unlike shredded draft animals who will consume fuel in standby status. Huge barns where built on the Plains to shed the horses and the feed needed to keep them over Winter Could very well be that an agricultural producer could could have and now can earn a larger profit by producing the fuel needed in house”. Not sure about yesteryear, but tofay there are road blocks put up that keep farmers who would try, from even trying.
Dammit sorry was comment that went to to wrong person
At a presentation promoting sunflower seed oil for diesel use, the promoters said 25% of acreage was used to feed the draft animals, while they claimed only 10% of acreage in sunflowers would be needed to fuel modern ag equipment.
Yes, but that’s for oil in a diesel engine, whereas the topic of the ill placed reply was with ethanol powered otto engines.
After Mr. Rockefeller told Mr. Ford, no you are not going to make stills for farmers to make fuel for your Model T’s you are going to make them use my fuel, he funded the WCTU.
Prohibition was created to further the demand of Big Oil. No alcohol!
Yesterday the Rockefeller brothers announced they will divest of oil stocks.
Let’s drink to that!
That’s a nifty conspiracy theory, that’s just missing one point:
Making ethanol out of crops with a pot still is incredibly wasteful. Even with modern massive continuous stills and cheap corn, it’s still just 27% over break-even.
It takes much more energy than you get out of it and the early cars weren’t particularily fuel efficient either, so the farmer would have had to spend a great deal of their land resources and income just to fuel their own tractors.
and on that note, making fuel out of corn makes little sense, as the majority of crops, in my understanding, are fertilized with petroleum products, which is just adding another step(and therefore more inefficiencies) to the process of moving yourself way faster than evolution intended you to go. HAD posts cargo and ebikes all the time. i think combustion fuels should be commonly constrained to uses where high torque or high speeds are necessary. or moving large ammounts. daily commute? bike. getting groceries? personal preference. plowing a field, delivering lumber, planes, ships? alternative energy is obviously preferred, but gas, diesel, jet fuel, thats an acceptable use. limiting the usage isobviously gonna work easier than cutting it out all together. im mpt saying get rid of your car. im just saying it isnt necessary for that five minute trip to the store for zone night’s dinner ingredients.
>daily commute? bike
As always anyone who does use a bike assumes that every one else’s usage patterns, road conditions, journey lengths, fitness etc are the same as theirs.
It’d be near impossible, and highly unsocial for me to use a bike for my 40 mile daily commute to a place that has no shower facilities for me to freshen up when I get there.
public transport is a joke and ridiculously expensive anywhere outside major metropolitan areas, (in fact it’s still ridiculously expensive even inside them).
Some of us have little choice other than to use a car for when we have to go places.
“…so the farmer would have had to spend a great deal of their land resources and income just to fuel their own tractors.” Don’t those who use that statement consider the fact that when draft animals where the sole source of power farmers did spend a great deal of their land resources and income to fuel the draft animals? You can shed a tractor without it consuming fuel, unlike shredded draft animals who will consume fuel in standby status. Huge barns where built on the Plains to shed the horses and the feed needed to keep them over Winter Could very well be that an agricultural producer could could have and now can earn a larger profit by producing the fuel needed in house”. Not sure about yesteryear, but today there are road blocks put up that discourage farmers who would try, from even trying.
The did, but the thermodynamic efficiency of a Ford T tractor fueled by moonshine would have been massively worse.
Yeast needs sugar, so you need grain, and you need to mash it (heat it for hours and hours), then ferment it, and then distill it three times. All those stages need fuel in and of themselves, whereas your horse would simply eat the grain and drink some water.
Suppose your pot still boiler is 50% efficient. You put in 100 liters of water containing 10% ethanol because we haven’t got special yeast strains yet that can handle more and you haven’t got the time. The first run is a stripping run where you boil a third of it off to catch 85% of the ethanol and you get 33 liters of 26% ethanol. The second run, again boil one third off and catch 85% which gives you 11 liters of 66% ethanol. This would already burn in a hot engine, poorly, so you distill it a third time and boil 2/3 off, and again catch 85% because the still won’t separate very well and 85% is at the upper limits of a good pot still – so you get 7.3 liters of 85% ethanol, which is about 60% of what you started from.
So you got 6 liters of absolute ethanol which has a heating value of 26.8 MJ/kg or 125 MJ. Meanwhile, you boiled half of your total amount of liquid at 50% efficiency which requires on the order of 250 MJ of energy, so your comparative thermodynamic efficiency from grain to fuel for the engine is already 1/3 of that of the horse. The thermodynamic efficiency of a horse is actually quite identical to a Ford T, so , whatever your horse eats, your engine needs three times as much for the same work.
Then you have to remember that yeast is a living organism too, which also eats its part of the job, and the fact that horses eat and convert cellulose which is indigestible to yeast, and we haven’t calculated the part yet where you have to heat the grains in water to 65 C for 9 hours to convert starches into sugars and then bring it to a boil, and how much energy -that- requires…
I wouldn’t be surprised if the input-output ratio was closer to 10:1 for the ethanol engine with farming and moonshining techniques of the early 20th century. It certainly wouldn’t have been superior to the horse, unless you’re a big sugar cane co-op with a large industrial distillery and a coal mine to fuel it.
I’m sorry: you get 60% of the ethanol input by using 200% the ethanol output heat value, which gives you an efficiency of 20% at the distilling step.
@Dax
I agree with your overall point that non-cellulose EtOH as a fuel source is inefficient but many of your assumptions are off.
1) You have to mash grain for 9 hours
No you don’t. Even assuming you’re doing a corn mash you only need to mash for 1-2 hours. Less if you’re lucky/have high quality ingredients(enzymes). If the vessel is insulated or large enough and designed to minimize surface area the amount of heat input after the initial temperature is reached is minimal.
2) You need special yeast to get above 10% alcohol
Even bread yeast can get into the low teens in ABV. Champagne yeast and some wild yeasts can get into the upper teens without intervention.
3)You only recover 30% EtOH from the wash with each run.
Unless you have no idea what you’re doing and make no attempt to control the temperature of the still you will have 70% or better ABV in the liquid you collect from the condenser. The efficiency isn’t about extraction of alcohol from the wash left in the pot, it’s about separation of water &c from the EtOH in the output side of the still. Reflux stills were well known and used in the spirits trade in the time frame we’re discussing. The only reason to use a pot is to save initial investment costs or to preserve flavor characteristics of beverages. Pot stills have the same theoretical limit as reflux stills, ~95% ABV, this is not related to efficiency of the equipment but the effects of EtOH in solution with water and the method of separation.
you can still run most mechanical-injection diesels on pretty much anything after starting them on diesel or bio-diesel, as long as it has sufficient lubricity to keep the injector pump happy. there were and still are plenty of specifically designed multi-fuel diesels; the White engine in the AM General M35A2 being a good example. not sure how common-rail diesels would handle anything other than regular diesel, since I have zero experience with that.
One power plant I was familiar with ran 95% natural gas and 5% diesel. (This plants output was around 1MW). The diesel provided the lubrication. A good winter blend for my Datsun diesel was 70% Diesel #1 (non-lubricating, but non-gelling) and 30% Diesel #2 (for lubrication)..
He’s Groot!
Greetings from Augsburg, where Diesel invent the Diesel (running by Diesel) ;-)
And I attended Augsburg College (not in Augsburg) without being on the Augsburg College campus. B^)
Well, when he showed his newly invented engine at the world fair, it actually used peanut oil as fuel.
Diesel engines are on the list of top 4 things that absolutely fascinates me for some odd reason.
other 3 ?
Yeah. OP please deliver.
How about when a diesel engine is out of control, or a ‘runaway’ . Scary amazing. Just high revs and blue smoke. Only way to stop it is to choke it out…..wait what?
Someone from the Diesel Mechanics classroom told of the time a student failed to properly govern one of the engines. Everyone headed for the doors when the engine started winding up, the last one to leave tossed a text book toward the intake. The book managed to block about 75% of the opening and was enough to slow the engine.
That generally works if you can toss a book or piece of wood over the turbo inlet. Otherwise I’ve heard talks of the air filter box collapsing when trying that trick and introducing new air inlets to block. I’m surprised that most diesels don’t have a run-away valve, but then again it is fairly rare.
Many big engines do, though as you mentioned a lot of the time something will collapse and let air in. A really good runaway, like a turbo oil seal failure, can suck the head gasket into the cylinders.
We were always told that a CO2 fire extinguisher will stop a runaway with minimum risk to ruining the engine, regardless of the cause of the runaway.
“…for doing heavy-duty work like driving large-scale electrical generators” at many power plants diesel is the backup fuel supply for the Fairbanks-Morse engines that consumed natural gas in normal operations. Not to say are aren’t power plants that consume diesel in normal operations. I’d hate to be buying that power. For decade the effective rate I pay for electric has been steady at 10 cents. Good grief I reached a point where I can say I have been buying electric for decades, better than the alternatives I suppose.
The US used to use a lot of oil in electrical power generation. That changed after the arab oil embargo in the 1970s
Every country used diesel for electrical generation at some point or another. One more thing to consider is that today’s industrial diesels can exceed 50% thermal efficiency. I suspect that is the ceiling of a reciprocating mass engine, and those are two stroke engines that are turbocharged. I wonder if tesla turbines could be tested as engines, their friction points are very low and as turbines they are in the mid to upper 90% efficient, however there is much debate of that 90% efficiency rating, like any engine there is an efficiency range and where that efficiency range is present it would need to be tested.