Also, this led to the development of the Napier Deltic which avoided having twice as many crankshafts as cylinders by arranging three cylinders in a triangle with a crankshaft at each corner:
As to aircraft diesels, USSR had a few bombers in its fleet equipped with diesels (TB-7). Some of them actually took bombing raids over Germany in autumn of 1941.
Was the power to weight ratio of the gas turbine the most important thing? I always understood that it was the ridiculous simplicity of the gas turbine that was so great.
"Previous two-stroke designs were quickly banished as emissions standards started to get tougher. The design is such that unburned fuel and lubricating oils are released through the exhaust, causing emissions to be much higher. However, EcoMotors believes its design has overcome this challenge."
The article seems woefully vague on the details here. How do they overcome this challenge? Having lived in a country where there were some two stroke cars allowed on the road, believe me it is no fun. A two stroke subcompact used to generate more smoke and fouler smell than a freaking 18 wheeler (and yes I am talking about the Trabant).
So one would have to be extra sure that they have overcome this challenge before believing any of their hype. I would be very suspicious of any car that actually burns lubricant.
I would be excited to see an engine based on solenoid and using magnets as springs. Has anyone ever tried to make a cylinder whose piston is composed of a highly durable magnet at one end, which is encased in a coil. The bottom is basically a magnet which repels the piston, and a mechanical spring is also used to keep the process going.
When the fuel will ignite and expand there will be a huge change in EMF, perhaps that could be used to charge a capacitor which can then offload it more slowly into a battery. In this way mechanical parts are reduced and frictional losses are kept at a minimum since I am not driving a crankshaft, which then feeds into a dynamo with gearing.
I've heard about solenoid engines, but has anyone ever undertaken something like this? I am sure that tons of people must have this in their heads, but has anyone also used a tesla coil with a variable AC to control the motion of the piston? That is we can also remove the bottom magnet and the mechanical spring. This would be something awesome to make, and I wonder if it is feasible to do so.
One of the biggest worries would be the lack of appropriate magnets. Neodymium (NdFeB) start losing magnetic strength above 60 C and it becomes completely demagnetized before 90 C. So, one of the reasons why someone hasn't done this might be lack of an cost effective alloy which can remain magnetized at those temperatures. I really can't think of another reason.
I'm working on a design in the same ballpark as this, and I found that NASA has something similar as well (if not a bit more mechanically complicated than my design); I couldn't find a nice overview but I did find a couple of links to PDF's describing the test and analysis of their sterling-powered linear-alternator design:
It will take me time to go through them properly as there are some concepts in them which I don't know about. (I just graduated out of high school a few months ago)
Do you mind if I email you questions about what I've read? I have lots and lots of them.
Thanks again.
P.S. - I am quite dumb. I tend to ask stupid questions so please take that into account. :)
On the other hand I think that material science will have the answer to this sooner or later. It will be really hard to make substances that can resist getting demagnitized due to jiggly-jiggly motions#, but maybe someone will come up with a way to make a crystal of domains that can stick together under extreme conditions.
By the way, there is another design possibility over here the piston can be the coil and casing can be a liquid cooled magnet. We could transfer the current using graphite, or something. However, I doubt that the cost vs. benefit scenario will be on our side.
Two-stroke engines are what you find in lawnmowers (the non-riding kind), weed whackers, leaf blowers, chain saws, etc. because they're lighter than 4-stroke engines.
As mentioned in the article, the ones in those devices are terrible for the environment. They burn the oil as well as the gas, which for whatever reason means they emit way more pollution (not CO2, but stuff like carbon monoxide) than car engines. From Wikipedia:
> A 2001 study showed that some mowers emit the same amount of pollution (emissions other than carbon dioxide) in one hour as driving a 1992 model car for 650 miles
It sounds like this engine is a 2-stroke engine that does not do that, which has serious potential. Some of the fuel efficiency gains probably come from the fact that, as I said before, 2-stroke engines are lighter for a given desired power.
Weed whackers, leaf blowers, and ESPECIALLY chain saws remain two stroke for a special reason- they can be operated at virtually any angle. This is because the lubricating oil is carried in the air/fuel mix; if you turn a 4 stroke on it's side during operation, it will become oil starved and quickly seize.
I haven't any evidence, but I suspect those motors use a dry sump, which results in significant added complexity. You are right, it can be done, but it's usually reserved for racing engines.
Unfortunately the article doesn't say why their design uses fewer moving parts. Opposing cylinders is not a new idea (look at any Porsche or Subaru), although on the picture the combustion chamber is located on crankshaft side... The lack of valves isn't new: diesels don't have them neither do 2-stroke motorcycles.
So I'm eager to see what's the secret ingredient here?
Maybe the new design solves the problem traditional 2 strokes have that makes them pollute so much. The intake and exhaust valves are both open at the same time, which puts part of the fuel right into the air.
I can't really tell from the flash movie on the ecomotors site whats happening with the valves. I do see some slits that could serve as the intake port when the cylinder is fully open. And a tiny round thing which could be the exhaust port sits at the center of the cylinders length. Maybe the exhaust port is electronically operated and is closed by the time the 2 cylinders open as far as the intake ports?
Actually, making a 2-stroke that doesn't require both valves be open solves two problems. There's the fresh gas flowing right out the exhaust, and there's the limitations in compression ratio. Higher compression ratios result in higher efficiency, but the 2-stroke doesn't work right at high enough compression ratios.
These opposing pistons seem to be located in the same cylinder. It's two opposed cylinders with four pistons total. A Porsche flat six has six opposing cylinders and six pistons (one in each cylinder) in comparison.
If I recall correctly, in this design the engine has 2 cylinders (2 pistons each) and each piston is linked to the opposite piston on the other cylinder. In older designs you just have 2 pistons per cylinder but no cross-linked pistons.
The horizontally opposed engine (aka flat N) is nothing new. More specifically I know it has been in Honda motorcycles since the 1970's. Cars and other devices likely too but I have no first hand knowledge of that.
Here they are giving it a new name and say they can reduce the amount of moving parts by 50%. There is no information on what "parts" they are removing which I would find to be the most interesting piece of information. The comparison of two and four strokes engines is also misleading.
After a quick dig:
If you go to eco's website they specifically say this is a two stroke engine; the article linked has incorrect information.
They are reducing the amount of parts because they are using a two stroke instead of a four cycle.
It seems the only real cool part of this engine, to me, is that it is designed "modular," it should be more cost effective to add on additional cylinders instead of having multiple facilities dedicated to different configurations.
Flat configurations have been used in cars and motorcycles for decades.
Huh? The article mentioned it was a two-stroke engine:
"But that’s only part of the story--the OPOC engine also features a two-stroke design. The benefit here is that a two-stroke engine delivers a power pulse with every revolution of the crankshaft, as opposed to the four-stroke engine which fires each cylinder on every other revolution."
The type of engine you are referring to is called a 'boxer', and it has been in use in many other places from well before Honda ever used it.
Most notably in motorcycles probably the BMW brand, in car engines there was the Citroen 2CV and the VW beetle as well as many others, but that's not the same kind of engine as the one depicted in the article.
http://en.m.wikipedia.org/wiki/Junkers_Jumo_205
Also, this led to the development of the Napier Deltic which avoided having twice as many crankshafts as cylinders by arranging three cylinders in a triangle with a crankshaft at each corner:
http://en.m.wikipedia.org/wiki/Napier_Deltic
These had extremely good power to weight ratios - eventually eclipsed by gas turbines.