Note: Descriptions are shown in the official language in which they were submitted.
CA 02227124 1998-03-27
1 ~i
ATTAIN TECHNOLOGY INC.
"A - 2NVT"
Or
ATTAINS - 2 NEW VALVE TRAINS
Designed And Pre ared By
NICHOLAS M. OTTLYIC
March 26, 1998
7 Aylesbury Road, Islington, Ontario M9A 2M3 Telephone: (416) 239-6242
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intro - i
INTRODUCTION
The submitted two - (2) valve trains by Attain deal
predominantly with valve springs - or rather - with their
absence in the valve trains, or their completely different
applications.
As the said valve trains are not exactly common-
place, some explanations are in order; as these comments do not
really belong into claims sections, they are presented here, as
an introductory material.
DESMODROMIC VALVE TRAINS
History
Created in a Pre-World-War II era, desmodromic valve
trains were applied to high-performance engines in racing cars
and motocycles. From that era, of note are the French auto-
maker Delage, that raced in Le Mans, British and Italian
motocycles by Norton, designs by Tonti and then later, in the
1950's, in the Mercedes-Benz racing cars, also entered at Le
Mans. Today, unfortunately, there is only one commercially
available engine with desmodromic valves: it is the famous
Italian make of Ducati.
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intro - ii
What Is A Desmodromic Valve Train ?
Briefly stated, it is a high-performance valve train
that operates without main springs to close the valves shut; but
even a Ducati uses a small helper-spring for its low-speed
operation; the Mercedes-Benz had no springs at all. - As to the
origin of the word "desmodromic", not even the automotive
historians can agree on its true meaning, nor can they tell us
how it originated.
Why Do Desmodromic Valve Trains
Command Such High Res ect ?
With no resistance of the main spring, the desmodromic
valve train doesn't meet too much mechanical resistance and can
operate with less friction, and it is quieter. However, its main
attribute lies in the fact that it allows a longer "open time"
for its valves, so that on the intake side, more air can be let
into the cylinder during an intake down-stroke - which simply
enhances the volumetric efficiency (Ve) of the engine. Similar
benefits are available to the exhaust valve. It is its "radical
timing" that causes the engine experts and analysts to state,
that one desmodromic valve is equivalent to two "regular valves".
Hence, it is a performance booster - but it comes at a higher
cost.
A 'desmo' valve train needs - if not a separate
camshaft, then at least - an extra cam-lobe and a separate
closing mechanisms to close the valve shut.
The only available desmo-type valve train today
(Ducati) is built with extreme precision and quality approaching
CA 02227124 1998-03-27
intro - iii
desmo - cont'd
a spring-wound Swiss watch, which makes its quite expensive.
Furthermore, Ducati engines can only be adjusted mechanically by
shims, calling for high skills or the services of a competent
technician. The service intervals are at the 12 to 15,000 km.
While this procedure is acceptable to a dedicated enthusiast, it
does not fit the image of modern maintenance-free auto engines
guaranteed to run without a tune-up for 160,000 kms.
To conclude, desmodromic valve trains are not new but
Attains fully automatic valve-lash adjusters are a novelty and
so are the previously claimed Attain valve Train Components and
Engine Ports that will further enhance the performance of this
very efficient valve train.
DSA
or
DYNAMIC SPRING ASSEMBLY
The Dynamic Spring Assembly, or DSA, is an Attain
designed derivative of a desmodromic valve train; its name stems
from is operation. The valve opens by a mechanism similar to a
desmo engine but while the cam-lobe opens the valve, a second
cam-lobe releasesthe pressure of a smaller spring that is used
to seal the valve. Hence, the opening of the valve is done as
freely as in a desmo valve train. When the said valve is being
closed, spring pressure is gradually applied to the valve till
it is sealed.
The use of this "dynamic spring" eliminates the use of
a second valve-lash adjuster used in desmo valve trains.
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intro - iv
dsa - cont'd
But since the Dynamic Spring Assembly shares with
Desmodromic Valve Trains virtually all 'Prior Art' components
and engine ports, its performance should be almost the same as
the latter one - but at reduced cost. - The DSA does not require
any periodic valve-train adjustments neither, i.e. it is
maintenance-free.
* *
PRESENTATION FORMAT
Section I of this Submission deals with Attains 2 New
Valve Trains and their two claims.
Because both New Valve Trains employ many 'Prior Art' features,
these have been assembled and duly listed in an Appendix.
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SECTION I
ATTAINS 2 NEW VALVE TRAINS
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- 1 -
DESMODROMIC VALVE TRAINS
BY ATTAIN
T~~fr»~
A camshaft-lobe of an SOHC/DOHC engine acts upon an
Attain valve train component (Prior Art) through a valve-
lash adjuster to open an Attain ~ Stem Valve (Prior Art), which
is also closed by a second cam-lobe on the same camshaft,
through a valve-lash adjuster and a closing fork (Prior Art),
pulling the said valve shut by means of a pull-up collar on the
said valve.
Attains Desmodromic Valve Trains
Recognizing the very high performance potential of the
desmodromic valve trains - but also its lack of functionality in
every-day's automobile, Attain Technology has designed several
models of this type of mechanism; they all have one feature in
common: their valve train tolerances are adjusted automatically,
so that the engines using them, do not require any adjustmenents
for the duration of their normal ilfe.
These new design features immediately transform the
desmodromic valve trains into:
a) a practical, every-day engine, and
b) dramatically reduce its component costs.
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- 2 -
desmo - valve trains - cont'd
Also, by adopting certain Attain components and engine
ports, the proposed valve trains by Attain not only retain their
previous performance potential, but they are increased by:
1) a reduced reciprocating weight, since many of
Attains valve trains components are lighter, allowing the
engine to achieve even higher RPM's than previously possible,
and -
2) Attains Parallel Flow Ports add further to the
already very high volumetric efficiency of the said engine.
The two camshaft lobes employed in a desmodromic valve
train are used in such a way, that the first camshaft-lobe opens
the valve, either by means of an intermediate component -
like a rocker-arm - while the closing of the valve is performed
by a second cam-lobe; however, since the closing of the valve
entails the lifting of the said valve, the closing mechanism -
most likely a rocker again - must be applied to the underneath
portion of the camshaft.
In the Attain-Desmo Valve Trains both the opening and
the closing mechanisms are provided with automatic valve-
lash adjusters that eliminate the periodic adjustment service
demanded by a "regular" (read: Ducati) desmo valve train.
As stated above, the Attain Desmodromic Valve Trains
can operate only in SOHC and DOHC engines, which excludes any
OHV engines.
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- 3 -
desmo valve trains - cont'd
Main Advantages Of An
Attain Desmo Valve Train
a) an Attain Desmo Valve Train is completely maintence-free
b) the production cost of the said valve train should be
considerably below its present expenditures. as its
tolerances are far more 'liberal', eliminating a lot of
precision parts
c) the said valve train uses many components that are
substantially lighter, allowing it to reach ~ even higher RPM
(revolutions per minute), thus achieving even higher terminal
horsepower
d) using Attains Parallel Flow Ports, the volumetric efficiency
of the said valve-train - already of very high order -
should be enhanced even further
e) the Attain Desmo valve train has a great deal of design
flexibility, since its valve-closing and valve-opening
mechanisms can operate either from a single, or two fulcrums.
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- 4 -
Figures For Attains Desmo Valve Trains
Figure 1, is an enlarged schematic - in cross-
section of an Attains Desmodromic Valve Train.
The valve shown is opened by an Opening Rocker OR,
which terminates with a Sliding Roller Adjuster at the camshaft
end. (SRA - Prior Art). The said valve is closed by a Closing
Rocker - CR, which pivots in a rotating adjuster, actuated by a
hydraulic adjuster. Thus, both the opening and closing
mechanisms are fully compensated for tolerances and do not
require any periodic adjustments. While the Closing Rocker is
'straight' - the Opening.- Rocker is off-set - and so are the
cam-lobes, sharing the same camshaft.
The valve mechanism shown is installed in an Attain
Parallel-Flow Port Type IB (Prior Art).
Figure 2, is an enlarged top view of the desmodromic
valve mechanism shown in Figure 1.
Both the Opening ~ Closing Rockers are encased in
Carrier - CA, which is supported by two End Bearings - EB. -
The Adjustment Lever- AL, rotates the inside of adjuster
assembly, in which the pivot of the Closing Rocker -CR, is
mounted eccentrically, so that the motion of the said lever
causes the fulcrum of the said rocker to operated from a
different geometrical center - effecting a tolerance adjustment.
Figure 3, shows the above valve train installed in a
high-performance, D/CIH (Prio:r Art) cylinder head, with an
Attain Parallel-Flow Port Type IB (Prior Art).
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- 5 _
desmo figures - cont'd
Figure 4, is a cross-section of desmodromic valve
train using an RLB (Roller Lift-Bucket) as a valve-opening
mechanism, which eliminates a rocker altogether. While the RLB
(Prior Art) has its own valve-lash adjuster, the closing fork
has its own adjustment mechanism, which is mounted eccentrically
on a rotating component.
Figure 5, is a cross-section of a desmodromic valve-
train which employs a Y-Rocker as an opening mechanism; the
valve-lash adjustment in the said Y-Rocker is in its valve-
tappet portion and the closing fork is adjusted by an eccentric,
rotating element, as in Figure 4, above.
Figure 6, shows an alternate valve-lash adjustment
mechanism, named "Rising Shoe", in which a hydraulic lifter is
incorporated in the arm of the closing rocker.
Figure 7, - depicts a "Rising Shoe" valve lash
adjuster installed desmodromic valve train emplyoing an RLB
valve mechanism. As can be seen, the closing fork rotated on a
solid, horizontal shaft, but its contact point with the closing
cam is regulated by the said adjuster.
Figure 8 a, show a cross-section of a desmodromic
valve train applied to T-Bar Mechanism (Prior Art). operating
in an Attain Type V (Prior Art) intake engine port; only 3 cam-
lobes are needed to operate 2 valves; the closing forks are
mounted on an eccentric rotating element.
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- 6 -
desmo figures - cont'd
Figure 8 B, is an overhead view of the engine shown
in Figure 8 A. It shows the location of the camshaft and its
opening rocker, which is mounted on a common, rotating element
with the closing rockers; the arms of the latter are not shown,
as they are placed below the rocker shaft and neither are the
elements of the T-Bar Mechanism.
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-
DYNAMIC SPRING ASSEMBLY
or
DSA
Abstract
A camshaft-lobe of an SOHC/DOHC engine acts upon an
Attain Valve Train component (Prior Art), provided with a valve-
lash adjuster to open an Attain ~ Stem Valve (P-A) which also
closed by a second cam-lobe on the same camshaft through a
mechanism that is connected by a small spring to a closing fork,
lifting the valve shut by means of a pull-up collar on the said
valve.
DSA
The DSA, or the Dynamic Spring Assembly is a
derivative of Attains Desmodromic Valve Train and makes use of
all Attains Valve Train Components and Parallel Flow Ports.
employed in the latter mechanism. Again, it can be used in
conjunction with SOHC and DOHC engines only.
Just like in the Desmo Valve Train the DSA Mechanisms
employ.two.cam-lobes: one opens the valve, the second one closes
it. The name "dynamic" was chosen to indicate, that in one valve
event the force of the closing spring is cancelled when it is
not needed - and then re-applied to seal the valve into its
seat.
The valve-closing mechanism is not connected rigidly
to the valve-closing spring, so that when the closing cam-
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dsa valve train - cont'd
lobe begins to move - it turns the mechanism freely but in its
last degrees it has to work against the force of the closing
spring to seal the valve off.
This arrangement also means that in the DSA mechanism
the second valve-lash adjuster is not required.
The operation of the DSA Valve Train is as follows:
1. the valve is opened by an Attain valve component - and
simultaneously, the spring pressure keeping the valve closed
is released
2. the valve is kept open as long as it is needed
3. closing of the valve starts when the closing cam begins to
push on the closing rocker
4. the valve is completely closed when the cam-lobe pushes
further against the 2- part rocker and thus seals the valve
5. hence, in one complete valve-event, the spring pressure is
released when it is not needed - and applied - only when it
is really required to seal t:he valve
6. only the valve-opening portion of the DSA valve train needs a
valve-lash adjuster; the closing portion's tolerance are
taken upby the spring's action.
Attains Dynamic Spring Assembly - just like the Desmo
Valve Train - can operate only in SOHC and DOHC (Single, or
Dual, Overhead Camshaft) engines.
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_ g _
dsa valve trains - cont'd
Main Advantages Of The DSA Valve Train
a) uses only a very short spring - which is applied only when it
is needed
b) the short spring is much cheaper than a second valve -
lash adjuster in the Desmo Valve Train
c) takes advantage of all Attain valve train components and new
engine ports available to a Desmo Valve Train
d) an engine that uses a DSA Valve Train will probably achieve an
85~ to 90~ performance plateau of a Desmo Valve Train.
e) flexibility of application: the DSA Valve Trains can use a
variety of springs - and can be applied in both single, and
dual fulcrum configurations, giving the designer a wide
selection of mechanisms to choose from.
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- 10 -
Figures For DSA Valve Trains
Figure 10 and Figure 11, portray in a schematic
fashion the 'Four Valve-Timing Events' that a valve in a Dynamic
Valve Train Assembly goes through; it shows a intake valve
being actuated by two rockers, placed in two different fulcrums,
being driven by one common camshaft with two cam-lobes.
Figure 10:
1. Valve Is about To be Opened - the Closing Lobe (CL)
releases the spring pressure applied against the closing fork,
coupled to the Closing Rocker (CR) by a Twist Coil Spring; the
said valve is now 'free' to be opened without any spring
resistance.
2. Valve is now fully opened - the Opening Rocker (OR)
pushes the valve open without any resistance of the spring force -
- which was "dialed-out."
Figure 11:
3. The Valve is in its seat - the Closing Rocker (CR)
doesn't meet any springs resistance - as yet.
4. The Closing Rocker (CR) is being supplied with an
ever-increasing spring pressure) as the Closing Lobe (CL) rises,
being and the Twist Coil Spring and transmits its force against
the closing fork of the Closing Rocker Aseembly.
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- 11 -
dsa figures - cont'd
Figure 12, is a.n analysis of spring pressure
application to a DSA valve; as seen in the graph, the pressure
that seals the valve in its seat is "dialed out" during its
entire 'open time' - and brought in again only when it is really
needed: to close it firmly shut, at the end of its time event.
Figure 13, shows two - of the several possible -
- spring applications to the closing arm. The upper image is a
top view of a concentric, short-torsion spring installation,
where the said spring is coupled to both ends of the device by
splines: in order to close the valve, the roller-ended closing
arm must be placed below the camshaft.
The lower image shows a Twist-Coil Spring being
applied to the closing fork; the shaded area on the closing cam-
lobe indicates the zone of applied pressure of the spring.
Figure 14, shows two different methods of application
of the closing rocker in a DSA 'Jalve Train. The upper image a) -
is a single-fulcrum installation, where both the opening and
closing rockers operate from the same geometric center. The
lower image b) shows two fulcrums, where the opening rocker and
the closing one are pivoting from two different geometric
centers.
Figure 15, is an actual-size cross-section of a DSA
mechanism using an RLB valve train component.
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- .L2 -
dsa figures - cont-d
Figure 16, is a DSA valve train with a Flat Spring
applied to the closing arm; please note, that it is the closing
arm that aligns directly with the closing cam, while the
opening cam-lobe is off-set.
Figure 17, shows a DSA valve train, in which two
adjacent valves are serviced by 3 cam-lobes, instead of the
four, that would be normally required.
Each valve is opened by its own cam-lobe - but the
closing action for both emanates from a single cam-lobe,
connected to 2 closing arms by splines of a short torsion spring.
The mechanisms uses an RLB component and is installed in an
Attain Type IV engine port.
Figure 18, is a cross-section of a DSA Valve Train
adapted to a XANTA II mechanism (Prior Art). Its rendition is in
'double-actual-size', or DSA, and shows a 1999 Porsche 911,
boxer 6 motor.
Its bore is 96 mm, the intake valve is 39 mm (dia. ) x
44 mm long and its Upper Valve Guide employs a spherical hydr.
tappet. - The Return fork is connected to a short Twist Coil
Spring.
It should be noted that the entire Attain DSA Valve
Train is only about 90 mm tall (vertically up from the deck
line); the original Porsche motor is 195 to 205 mm tall, which
makes the Attain offering a little lower than 50$.
