Sealing in Ricardo's sleeve valve engines 3

[THT]

These engines keep bothering me.

Was the lube oil consumption outrageous in modern terms? Would any modern fluids or materials or designs help there, if you were to implement something like that today?

How was the port sealing (for gasses, as well as and oil) done? I don't have access to details, what's online doesn't tell much.

Was it a good design, if you compare it to today's poppet valve engines (with multiple valves and adjustable valve timings and whatnot)? I mean, did the sleeve valve offer any inherent benefits, and how much of a drawback is the radial (side) rather than axial (head) flow? If the engine has charging?

 

[Lou Scannon]

The more rapid change in port area between closed and max was also a plus for sleeve valves (vs a conventional cam/poppet valve system).

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[140Airpower]

The quick port opening was an advantage. In fact, they seemed to have optimized the rate of port opening with the shape of the mouth. Ricardo also experimented with the amount of swirl which could be precisely optimized with that kind of a port. But, I think the lack of a valve head in the way was probably the greatest advantage.

 

[gruntguru]

Designers of modern engines probably salivate at the sleeve valve design's easy swirl production and the "revolve" shaped combustion chamber to help preserve that swirl.

je suis charlie

 

[Panther140]

tbuelna (Aerospace) 2 Dec 15 09:54

The debate regarding the relative merits of sleeve valves versus poppet valves has been going on for over half a century. Here's all you need to know about the subject- Every engine designer knows all about sleeve valves, as does every engine manufacturer. These people are not stupid. So if sleeve valves were so much better than poppet valves, all modern IC piston engines would be using sleeve valves. But none of them use sleeve valves, and most of them use poppet valves. So what does that tell you?


It tells you that there are smaller markets for applications where sleeve-valve engines are optimal. To refine a sleeve valve engine to the extent that poppet valve engines have been refined would require quite a large budget. ROI is non existent.

Heres all you need to know about the subject- Engineers are focused on delivering the promises that the sales department already made to customers. Customers, marketing, bean counters, and sales departments have a huge influence over what engineering departments do.

If engineers could just build and manufacture whatever they wanted, engines would be much more interesting than they are right now.

"Formal education is a weapon, whose effect depends on who holds it in his hands and at whom it is aimed." ~ Joseph Stalin

 

[140Airpower]

A great observation!
"....If engineers could just build and manufacture whatever they wanted, engines would be much more interesting than they are right now...."

And the follow-on has to be, ...until their companies go bankrupt...

 

[tbuelna]

And the follow-on has to be, ...until their companies go bankrupt...

Great point! One big aspect of designing a product for commercial mass production is balancing conflicting requirements such as cost, performance, reliability, emissions, etc.

 

[gruntguru]

"Heres all you need to know about the subject- Engineers are focused on delivering the promises that the sales department already made to customers. Customers, marketing, bean counters, and sales departments have a huge influence over what engineering departments do."

I disagree with that first sentence. An engine designer (or any engineer for that mater) should learn and debate every aspect of such things. The sleeve valve has lost out to the poppet valve, but areas of superiority remain and these are things to consider when looking to improve any existing design. There is no need for "real engineers" if the mentality is "that's the way we've always done it".

je suis charlie

 

[Panther140]

^ I agree with that 100%. Especially the part where you said "should".

The idea I was trying to communicate was that they are not able to unilaterally make platform changes on mass-produced engines. There are a lot of creative things that they can channel their energy into within the poppet-valve 4 cycle engine, for the time being. Customers and businesses are risk-aversive. The customers and other parts of the actual business act as checks and balances on what engineers execute.