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Efficient Engines

Revoltingest

Pragmatic Libertarian
Premium Member
I've been wondering if/when we might see compression ignition gasoline engines.
This is interesting....
 

Revoltingest

Pragmatic Libertarian
Premium Member
Btw, OP (opposed piston engines) date well before WW2,
but that was when they gained popularity.
Some advantages.....
- Lower piston speed per RPM.
- No valve train
- Compression ignition means no ignition system.
- No cylinder head to warp or leak.
- Balanced reciprocating forces.
- Uniflow (a term from steam engine design meaning hot & cold gasses contact separate surfaces)

Here's an early OP engine from around 1900...
 
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exchemist

Veteran Member
Btw, OP (opposed piston engines) date well before WW2,
but that was when they gained popularity.
Some advantages.....
- Lower piston speed per RPM.
- No valve train
- Compression ignition means no ignition system.
- No cylinder head to warp or leak.
- Balanced reciprocating forces.

Here's an early OP engine from around 1900...
Doxford built opposed piston marine engines from the 1920s. The Deltic was the most famous post-war engine of this type, I think (click for animation):
Napier Deltic - Wikipedia

Memorably for those of us who were boys in the late 1960s, A pair of them were the prime movers in this diesel-electric locomotive, which could pull the expresses of the day at 100mph with ease:
 

exchemist

Veteran Member
Gasoline? Diesel? Surely they are the past, not the future.
Yes. They are. But of some historical interest to mechanical engineers and allied professions (such as lubricating oil technologists like myself;)).

These things actually suffered from fairly serious emissions problems (You can see how smoky the Deltic locomotive is). I suppose they must have overcome them to some degree in the engine in @Revoltingest 's video, but I don't see them making a large-scale comeback. They might find a niche as prime movers in some hybrid vehicles I suppose.
 

Revoltingest

Pragmatic Libertarian
Premium Member
Yes. They are. But of some historical interest to mechanical engineers and allied professions (such as lubricating oil technologists like myself;)).

These things actually suffered from fairly serious emissions problems (You can see how smoky the Deltic locomotive is). I suppose they must have overcome them to some degree in the engine in @Revoltingest 's video, but I don't see them making a large-scale comeback. They might find a niche as prime movers in some hybrid vehicles I suppose.
Hybrids are also good candidates for regenerating gas turbines.
It's very efficient, but only at full power. For a small engine whose
job is only to continuously recharge batteries, it could work.
 

Revoltingest

Pragmatic Libertarian
Premium Member
Yes. They are. But of some historical interest to mechanical engineers and allied professions (such as lubricating oil technologists like myself;)).

These things actually suffered from fairly serious emissions problems (You can see how smoky the Deltic locomotive is). I suppose they must have overcome them to some degree in the engine in @Revoltingest 's video, but I don't see them making a large-scale comeback. They might find a niche as prime movers in some hybrid vehicles I suppose.
I'm sure the Kansas City Lightning engine had poor emissions.
But being a gasoline engine, it just didn't smoke much.
 

Revoltingest

Pragmatic Libertarian
Premium Member
I meant say one for diesel, not the discovery of fire ;-)

But you know too much about scrap iron engines to argue with
I remember the discovery of fire.
What a great day that was.
The inventor, Oog, never patented it.
(No patent office yet.)
 

exchemist

Veteran Member
Duh!

In 50 years, we shall see.
I'll wager that IC engines will smile & invoke Mark Twain.
That's a wager you will need to have with my son, as I shan't be around. But by then people like him will be running the auto companies. And none of this legislation is going to go backwards.
 

Wu Wei

ursus senum severiorum and ex-Bisy Backson
I've been wondering if/when we might see compression ignition gasoline engines.
This is interesting....

Mighty cool, but it is a darn big for 2.7 liters…2 stroke. Will be interesting to see if it is used in production. But lest we forget, the Wankel that was supposed to be better too
 

exchemist

Veteran Member
Mighty cool, but it is a darn big for 2.7 liters…2 stroke. Will be interesting to see if it is used in production. But lest we forget, the Wankel that was supposed to be better too
True but, unlike the Wankel, this is all known technology. OP engines are well-known, and my humble VW has both a supercharger and a turbo on it, giving a 1.4 l engine the power of a 2l one, with much greater part-throttle fuel economy.

It will be getting the details right, like the emissions, that may bedevil a new design like this. Diesel particulates? NOx? The rules are tightening all the time.
 

Revoltingest

Pragmatic Libertarian
Premium Member
Mighty cool, but it is a darn big for 2.7 liters…2 stroke. Will be interesting to see if it is used in production. But lest we forget, the Wankel that was supposed to be better too
It's a prototype, Booboo.
The Wankel was known from the outset to be inherently
fuel inefficient due to high surface to volume ratio of the
combustion chamber. But it had a niche where high
power to weight ratio was important & fuel economy wasn't.
 
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