dubious
Needs a life
Needs more time to ride!
Posts: 8442
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posted October 09, 2009 11:28 PM
 Edited By: dubious on 10 Oct 2009 07:29
Coates CSRV, ok wake up motorheads .LOL
OK, all you motor heads, especially Jim and Doug,
what is your opinion on this cylinder head and valvetrain design?
I have heard that the sanctioning bodies would not allow it for the poppet valve world would be turned on its ear.
When it came out 20 yrs ago and i first read of it in Hot Rod magazine, I thought it would be everywhere by now. Apparently the sealing materials on the rotating valve were not so good.
Since then science has moved forward drastically with ceramics etc.
Piston speeds were not what they are now in mass production, and now it seems the induction/ exhaust overlap inherent with this design would work well with low torque, high speed, high revving engines of today.... hmummf....
I am still stumped by the lack of its use.
Yamaha even bought rights 15 years ago.....
http://www.coatesengine.com/csrv.html
CSRV Rotary Cylinderhead
Coates Spherical Rotary Valve Cylinderhead
• Low manufacturing cost
• Low maintenance cost
• Low noise
• Low parasitic power consumption
• High efficiency
• High volumetric efficiency
• Flexibility of gas motion control
• High torque/power density
• High efficiency in part load operation
• Low knock tendency
• Low engine height for flexible vehicle styling
• Low pollution emission
• Alternate fuel compatability
• Clean engine block and compartment
• No liquid lube in any part of rotary valve
APPLICABLE IN
• SI/CI Engines with 2 or 4 Stroke Design
• Small/Large, Single/Multi Cylinder Engine
A new spherical port-type rotary valve system is incorporated with conventional reciprocating engines by replacing the traditional noisy cumbersome high pumping-loss poppet valve-train.
The operation of this new economical valve package has been proven durable (in extended dynamometer and road tests) and shown to deliver many superior engine performance features.
The only moving element in the new mechanism is one set of rotating spherical valves per cylinder mated with respective floating ports whose sealing actions are linked to the cylinder pressure variation. This creative concept has become a proven engineering reality thanks to recent advancements in design and some new material technology.
Among the beauty of the new invention is no need for costly modification in the existing manufacturing line of the present engine block. It is truly an engine technological breakthrough which offers revolutionized performance and convenience.
Absence of poppet valves and other operating accessories normally housed under the valve cover has permitted elimination of both oil lubrication and cooling water flow in the upper portion of the cylinder head. This reduces the overall engine height by as much as 20 cm from that of its conventional counter part, and maintains a clean engine.
The new, patented simple valve-train unit has minimized the area of contact for fluid flow through the gas exchange ports by making use of wide-open circular cross-sections. This significantly cuts down the pumping loss and unmatchable increases the volumetric efficiency to achieve a high torque/power-density engine.
The new dynamically balanced rotating spherical port valve eliminates entirely mechanical noise produced by current poppet-valve components. Hissing sound generated as gas flow squeaks through the narrow annulus valve opening in the conventional cylinder head is no longer audible. At the same time, the new unit cuts down, by an order of magnitude, the need for power out of the crankshaft. Normally a big parasitic power drain is required in conventional engines to drive the valve train.
Performance & Excellence
SUMMARY
Many production engine blocks mounted with Coates rotary port-valve cylinder heads have been operated in the original host vehicles to implement extensive tests. For example, one of them has successfully been driven over 150,000 miles and shows many performance advantages. Some proven engine characteristics are listed below along with the best probable reasons for the observed results.
LOW MANUFACTURING COST:
• Far fewer parts in simple valve mechanism
• Simple cylinder head
• No costly change in manufacturing line of the existing engine block
• Shorter assembly time
LOW MAINTENANCE COST:
• Simple package to produce fewer troubles
• No oil in the cylinder head to burn or leak
• No liquid lubrication in any part of the rotary valve
• No cooling water in the upper portion of the split cylinder head
LOW NOISE:
• Absence of noisy reciprocating valve train smooths intake
• gas flows and no valve bounce
LOW PARASITIC POWER CONSUMPTION:
• Low pumping loss in gas exchange process
• Low power required for rotary valve operation
HIGH EFFICIENCY ENGINE:
• High critical compression ratio - No hot exhaust valve
• Low parasitic power consumption
• Low pumping loss
HIGH VOLUMETRIC EFFICIENCY:
• Fully opened circular valve ports
• Low-temperature intake port
• No back flow of residual gas
• No need for valve overlap
FLEXIBILITY OF GAS MOTION CONTROL:
• Near zero tradeoff problem between gas motions and volumetric efficiency
• Fully opened circular cross-sectional port|
• Staggered variable valve openings
HIGH TORQUE/POWER-DENSITY ENGINE:
• High volumetric efficiency
• Fewer parts in the engine and simple cylinder head
• High thermal efficiency
• High engine speed-dynamically stable rotating valve with no valve floating problem
HIGH EFFICIENCY IN PART-LOAD OPERATIONS:
Low pumping work
• Use less than 10% power to operate the poppet valve mechanism
LOW KNOCK TENDENCY:
• No high-temperature wall, e.g. exhaust poppet valve
• Low filling work to the intake charge
LOW POLLUTANT EMISSIONS POTENTIAL:
• No oil burned in the valve ports
• Absence of valve overlap
• Low-temperature cylinder head wall
• High exhaust gas temperature
CLEAN ENGINE BLOCK AND COMPARTMENT:
• No oil leakage from the valve cover
• No coolant leakage from the cylinder head/gasket
• No need for valve cover ventilation
FLEXIBILITY OF AUTO-BODY STYLING:
• Low overall height- Absence of valve cover
• No water jacket in upper portion of the cylinder head
• Compact and clean engine package
____________
natural selection.....
destiny will overcome intervention.
Some are not worthy of the effort.
  
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dubious
Needs a life
Needs more time to ride!
Posts: 8442
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posted October 09, 2009 11:30 PM
PTV should be really easy to control too! LOL
____________
natural selection.....
destiny will overcome intervention.
Some are not worthy of the effort.
|
dougmeyer
Needs a job
moderated
Posts: 2713
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posted October 10, 2009 06:56 AM
It didn't catch on simply because it wasn't better. It's heavy, manufacturing costs (were) high and fuel specifics actually weren't any better if not worse. In retrospect, probably due to poor "port" velocity. I have all the original brochures on my shelf. Different, not better.
The development that had the biggest impact on valve actuation and performance (rpm) was pneumatic springs. But even this poses problems for non-race applications.
D.
____________
It's not that I think you're dumb, it's just that so much of what you know isn't true....
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dubious
Needs a life
Needs more time to ride!
Posts: 8442
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posted October 10, 2009 08:49 AM
Too many hurdles in the sanctions, too many problems with sealing.
materials have improved drastically since it inception 20 yrs ago, as has performance data aquisition and knowledge.
Not enough performance R&D invested with the new materials and technology either maybe?
These aspects might not ever overcome the weight of the rotating assembly?
Pity.
____________
natural selection.....
destiny will overcome intervention.
Some are not worthy of the effort.
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