Coates cylinder heads, no more poppet valves!

[oversteerxj12]

http://www.coatesengine.com/index.html

Saw this idea many years ago, why hasn't it took off?
I can't see any real dissadvantages and it seems a far simpler solution to the inherent problems with poppet valves than the alternative "piston valve" polish 4 stroke design generating interest elsewhere in this section.
Cylinder heads are available to retrofit to a few engines (mostly yank v8s I think) and have shown massive gains over conventional heads.
Why isn't every car manufacturer working on these?

[skeggysteve]

Thanks for that link.

It's a very interesting idea, like you, I wonder why it hasn't really taken off.

[That Daddy]

The unknown and cost probably manufacturers generally like to play safe.

[dickkark]

We have fitted their generators on some trucks for water purification plants in Africa.
They certainly run/idle smoother than the conventional diesel engine which they are based on but this also may be down to the fuel used and the fact they are new.

But the company we build these for are full of praise for the genny units and they use good components on them right down to the nuts,bolts and hose clamps that sort of thing.

I`ve no idea what sort of money they are either but they are not cheap,I remember being told that they are almost twice the cost of a similar german machine.

[ZeeTacoe]

oversteerxj12 said:

http://www.coatesengine.com/index.html
Cylinder heads are available to retrofit to a few engines (mostly yank v8s I think) and have shown massive gains over conventional heads.
Why isn't every car manufacturer working on these?

I'll bet if you put bigger conventional valves on the engines you'd end up with a similar performance boost. Reasons why no one else is using them is because it'll be bloody hard too keep a decent seal between the valve and head. Those 'valve' are going to be spinning at quite a high rate and sealing that gap at high engine speeds will be a challenge. Just look at the problems mazda has had with the wankel engines.

[rev-erend]

Looks very interesting.. but as mentioned already the seal between the valve and head looks tricky but they claim to have solved that..

Would be interesting too hear from someone like Marquis Rex on this engine..

I think a big part of any big companies decision to not use something like this is patent costs and licencing.

How long did we all have to endure crappy brakes when we all knew 4 pot caliper discs was the way to go .. they tried every which way to get something good enought without much manufacturing cost .. sliding calipers etc.. etc..

[annodomini2]

rev-erend said:

Looks very interesting.. but as mentioned already the seal between the valve and head looks tricky but they claim to have solved that..

Would be interesting too hear from someone like Marquis Rex on this engine..

I think a big part of any big companies decision to not use something like this is patent costs and licencing.

How long did we all have to endure crappy brakes when we all knew 4 pot caliper discs was the way to go .. they tried every which way to get something good enought without much manufacturing cost .. sliding calipers etc.. etc..

This idea has been around for a very long time, the problems are always related to sealing and maintaining the reliability of those seals, it is a similar problem to that experienced by wankel engines with the rotor tip seals.

If they've fixed it then manufacturers will be wary as the company who holds the patent will probably charge an arm and a leg for licensing rights.

[rev-erend]

Steel component revolving in an alloy head..

Different expansion rates.. (alloy has more at a lower temp).. means a gap at working temps..

Anyway - got to stop looking at this old technology and get on with my hyrogen fuel cell work

[Mr2Mike]

A lot of the stuff on the Coates web site appears to be pure techno-gibberish, irrelevant waffle added to bulk up the site. One point I noted was this:

Coates said:

In the 1950 and 1960s combustion engines utilized compression ratios of 12 to 1. and higher, producing higher horsepower (H.P.), more torque (TQ) and a higher (thermal efficient engine) Engine efficiency was at approximately 35%. Governments around the world found that tetraethyl lead was the lead component in the gasoline at that time.

The findings were that this lead component in the fuel was extremely hazardous to human health and the world’s environment; it was then removed from the fuel. This caused the high compression automobile engines to develop hot spots in the combustion chamber and the hot spot was found to be the exhaust poppet valve. It was getting red hot, causing pre-ignition and damage to the engines. The only remedy for this was to lower the compression ratio of all engines; this resulted in a lowering of thermal efficiency from an engine having 35% efficiency to 22 to 24% efficiency. This included the less dense fuel with the lead removed.

1. How many production car engines had a CR of anything like 12:1 in the 50's? [url]This|http://en.wikipedia.org/wiki/Petrol_engine#Compression_ratio[/quotes] suggests 6.5:1 to 7:1 would be more like it.

2. Even assuming they did, how does he work out that a drop of 12:1 to the 9:1-10:1 of modern engines has resulted in a whole 10% drop in thermal efficiency? Many modern engines have CR's of 11:1 or higher running on pump fuel anyway.

This bit of waffle made me laugh:

Coates said:

There are many types of rays:

* Light Rays
* Ultraviolet Rays
* Infrared Rays
* Microwave Rays
* Laser Rays
* Radioactive Rays
* Solar Rays
* Sun Rays
* Radio Wave Rays
* Xrays

So, ionizing radiation and electromagnetic radiation then?

Edited by Mr2Mike on Monday 15th December 19:32

[wildoliver]

I'm surprised no-one has spotted the obvious flaw with the demo video of how the engine works.

Hint. Involves cylinder volume.

[GavinPearson]

I looked at their site and they don't even mention NOx. Unless you have good NOx control you couldn't use it for a road vehicle and the combusion chamber shape may make getting there an extremely difficult task.

[That Daddy]

GavinPearson said:

I looked at their site and they don't even mention NOx. Unless you have good NOx control you couldn't use it for a road vehicle and the combusion chamber shape may make getting there an extremely difficult task.

He does in the video agree with the sealing problems though,bearing in mind most modern engines can cover 200k + with out major attention valves,cams etc as annodomini2 already mentioned.