Inside the Cylinder of a Diesel Engine – by Harry Ricardo

Jake60

Full Access Member
Joined
Feb 3, 2019
Posts
136
Reaction score
184
Location
New Jersey
Bear with me if I seem like a kid in a toy store, I'm just fascinated with my new 7.3idi :p I had no idea what indirect injection even was a couple weeks ago. I can't stand not knowing about stuff, so reading this and that article referencing the "Ricardo V" combustion chamber used by the idi. Harry Ricardo was a pioneer of internal combustion and inventor of the prechamber or "vortex chamber" system of ignition and flame propagation. The thought journey inside a cylinder ignition cycle is the clearest I've ever understood a diesel power cycle. Anyway here it is for anyone interested...

--------------

Sir Harry Ricardo (26 January 1885 – 18 May 1974) was one of the foremost engine designers and researchers of the internal combustion engine. During the First World War, Ricardo designed significantly improved engines for early British tanks. Between the wars, he researched the physics of internal combustion and the design of combustion chambers. This work led to the use of octane ratings, stratified charge, and intake swirl (vortex). Ricardo was instrumental in the development of the sleeve valve engine, particularly for aircraft use. His work and research contributed greatly to the high-power aircraft engines of World War II. After the war, he continued to develop the Diesel pre-combustion chamber (Comet), originally designed in the 1930s, which made high-speed diesel engines possible.


The following excerpt is from a lecture Harry Ricardo gave to the Royal Society of Arts on 23 November 1931.

I am going to take the rather unconventional course of asking you to accompany me, in imagination, inside the cylinder of a diesel engine. Let us imagine ourselves seated comfortably on the top of the piston, at or near the end of the compression stroke. We are in complete darkness, the atmosphere is a trifle oppressive, for the shade temperature is well over 500 Celsius – almost a dull red heat – and the density of the air is such that the contents of an average sitting-room would weigh about a ton; also it is very draughty, in fact, the draught is such that, in reality, we should be blown off our perch and hurled about like autumn leaves in a gale. Suddenly, above our heads, a valve opens and a rainstorm of fuel begins to descend. I have called it a rainstorm, but the velocity of droplets approaches much more nearly that of rifle bullets than of raindrops.

For a while nothing startling happens, the rain continues to fall, the darkness remains intense. Then suddenly, away to our right perhaps, a brilliant gleam of light appears, moving swiftly and purposefully; in an instant this is followed by a myriad others all around us, some large and some small, until on all sides of us the space is filled with a merry blaze of moving lights; from time to time the smaller lights wink and go out, while the larger ones develop fiery tails like comets; occasionally these strike the walls, but, being surrounded by an envelope of burning vapour, they merely bounce off like drops of water spilt on a red hot plate.

Right overhead all is darkness still, the rainstorm continues, and the heat is becoming intense; and now we shall notice that a change is taking place. Many of the smaller lights around us have gone out, but new ones are beginning to appear, more overhead, and to form themselves into definite streams shooting rapidly downwards or outwards from the direction of the injector nozzles.

You must be registered for see images attach

Fuel igniting as it is injected into a diesel cylinder. (Bosch image)

Looking round again we see that the lights around are growing yellower; they no longer move in a definite direction, but appear to be drifting listlessly hither and thither; here and there they are crowding together in dense nebulae, and these are burning now with a sickly, smoky flame, half suffocated for want of oxygen. Now we are attracted by a dazzle, and looking up we see that what at first was cold rain falling through utter darkness, has given place to a cascade of fire as from a rocket. For a little while this continues, then ceases abruptly as the fuel valve closes.

Above and all around us are still some lingering fire balls, now trailing long tails of sparks and smoke and wandering aimlessly in search of the last dregs of oxygen which will consume them finally and set their souls at rest. If so, well and good; if not, some unromantic engineer outside will merely grumble that the exhaust is dirty and will set the fuel valve to close a trifle earlier.

So ends the scene, or rather my conception of the scene, and I will ask you to realise that what has taken me nearly five minutes to describe may all be enacted in one five hundredth of a second or even less.

– Harry Ricardo

https://oldmachinepress.com/2013/01/02/inside-the-cylinder-of-a-diesel-engine-by-harry-ricardo/
 

Jake60

Full Access Member
Joined
Feb 3, 2019
Posts
136
Reaction score
184
Location
New Jersey
It's Einstein level genius IMO to be able to envision how a flame front needs to propagate in an efficient engine cylinder, and then design a combustion chamber that does just that. Before his work they were just guessing what went on in there.
 

Jake60

Full Access Member
Joined
Feb 3, 2019
Posts
136
Reaction score
184
Location
New Jersey
Just so you know, I'm sure that most of us on here feel the same way. I know that I do!:Thumbs Up

Love it :D I'm really impressed by my 6.0, I spent a long time with it down to the nuts and bolts, it's an amazing piece of technology and without breaking a sweat on stock injectors it should should see 450hp . But the IDI is one that fascinates me, if an engine could have a soul (not discounting that they do) the IDI would have one. It is just so pure and elegant in it's simplicity it's a work of art IMO.
 

Jake60

Full Access Member
Joined
Feb 3, 2019
Posts
136
Reaction score
184
Location
New Jersey
And it's given me time to contemplate things like this, flame front propagation and vortex sworl. I always just pictured a static cylinder full of air getting squished, fuel sprayed in an it explodes. Never stopped to consider what "explodes" actually means, and why they could only get <1000 RPMs out of Diesel until Ricardo's insights. Working on the 6oh it was all I could do to keep the schematics in my head long enough to realize how it actually works. The power cycle on an IDI is marginally more complex than my dogs begging routine at the fridge, but the inner workings a modern miracle.
 

Thewespaul

Supporting Member
Supporting Member
Joined
Jul 27, 2015
Posts
8,796
Reaction score
8,059
Location
Bulverde, Texas
If I remember right, there’s a documentary on Ricardo’s experiments and findings on YouTube
 

david85

Full Access Member
Joined
Feb 21, 2008
Posts
4,829
Reaction score
1,095
Location
Campbell River, B.C.
It takes one kind of genius to discover and understand these things. It takes another to explain known concepts to a laymen. The third type? They achieve a near god-like level of both, which allows them to continuously strengthen each halves of the mind. Reminds me of Nikola Tesla.
 

Latest posts

Forum statistics

Threads
91,290
Posts
1,129,826
Members
24,106
Latest member
lewisstevey7

Members online

Top