U.S. patent application number 11/764970 was filed with the patent office on 2008-12-25 for desmodromic variable valve actuation.
Invention is credited to Emmanouel Pattakos, John Pattakos, Manousos Pattakos.
Application Number | 20080314342 11/764970 |
Document ID | / |
Family ID | 40135192 |
Filed Date | 2008-12-25 |
United States Patent
Application |
20080314342 |
Kind Code |
A1 |
Pattakos; Manousos ; et
al. |
December 25, 2008 |
DESMODROMIC VARIABLE VALVE ACTUATION
Abstract
The combination of the Fully Variable Valve Actuation or FVVA
system with the Desmodromic control results in a fully functional
FVVA rid of valve springs and any other kind of the restoring
springs of the art.
Inventors: |
Pattakos; Manousos; (Nikea
Piraeus, GR) ; Pattakos; John; (Nikea Piraeus,
GR) ; Pattakos; Emmanouel; (Nikea Piraeus,
GR) |
Correspondence
Address: |
PATTAKOS Manousos
Lampraki 406, P.C. 18452 GR
Nikea Piraeus
GR
|
Family ID: |
40135192 |
Appl. No.: |
11/764970 |
Filed: |
June 19, 2007 |
Current U.S.
Class: |
123/90.16 ;
123/90.27; 123/90.44 |
Current CPC
Class: |
F01L 1/042 20130101;
F01L 1/30 20130101; F01L 1/34 20130101; F01L 13/0063 20130101 |
Class at
Publication: |
123/90.16 ;
123/90.27; 123/90.44 |
International
Class: |
F01L 1/34 20060101
F01L001/34 |
Claims
1. A desmodromic mechanical valve train system for the control of
the motion of a valve of an engine, characterized in that the valve
lift profile is variable according the state of at least one
control member, thereby a desmodromic variable valve actuation
system is provided.
2. A mechanical variable valve actuation system for the control of
a valve of an engine, characterized in that the valve motion is
controlled desmodromically.
3. As in claim 1 wherein a first control member and a second
control member provide independently variable valve lift and valve
duration.
4. As in claim 2 wherein the variable valve actuation system is a
fully variable valve actuation system providing independently
variable valve lift and valve duration.
5. As in claim 2 wherein an eccentric pin rotates or reciprocates
or oscillates in synchronization with the engine, said eccentric
pin, via a connecting rod, displaces a roller, said roller is in
substantially simultaneous abutment to two control surfaces of a
control member, said two control surfaces have form and location
such that, in combination with the connecting rod action, force the
roller to perform a desmodromic motion, said roller imparts, via
another connecting rod, its motion to the valve.
6. As in claim 2 wherein an eccentric pin rotates or reciprocates
or oscillates in synchronization with the engine, said eccentric
pin, via a connecting rod, displaces a roller, said roller is in
substantially simultaneous abutment to two control surfaces of a
control member, said two control surfaces have form and location
such that, in combination with the connecting rod action, force the
roller to perform a desmodromic motion, said two control surfaces
include a lost motion part and an actuation part, said roller
imparts, via another connecting rod, its motion to the valve.
7. A mechanical constant duration variable valve actuation system
for the control of the valve lift of a valve of an engine,
characterized in that the valve motion is controlled
desmodromically.
8. As in claim 7 wherein an eccentric pin rotates or reciprocates
or oscillates in synchronization with the engine, said eccentric
pin, via a connecting rod, displaces a roller, said roller is in
substantially simultaneous abutment to two, substantially immovable
relative to the engine, surfaces, said two control surfaces have
form and location such that, in combination with the connecting rod
action, force the roller to perform a desmodromic motion, said two
control surfaces include a lost motion part and an actuation part,
said roller imparts, via another connecting rod, its motion to the
valve.
9. As in claim 2 wherein a reciprocating or rotating or oscillating
pin, via a connecting rod, actuates desmodromically a constant
duration mechanism which in turn actuates desmodromically a lost
motion mechanism, which in turn actuates desmodromically the valve.
Description
[0001] The closest prior art is the U.S. patent application
11759392, of Jun. 07, 2007.
[0002] In a Fully Variable Valve Actuation, or FVVA, and in a
Variable Valve Actuation, or VVA, system, the valve lift or the
valve duration or both can vary to approach the desirable valve
lift profile.
[0003] A Desmodromic valve train, as its name implies, holds the
valve during the opening process and also during the closing
process, eliminating the need for restoring valve springs.
[0004] This invention combines the FVVA/VVA with the Desmodromic
mechanism to provide a valve train rid of restoring springs, fully
functional, lighter, shorter, capable for higher revs, cheaper,
with lower friction etc.
[0005] FIG. 1 shows a desmodromic fully variable valve actuation
mechanism,
[0006] FIG. 2 shows a Lost Motion desmodromic variable valve
actuation mechanism,
[0007] FIG. 3 shows, from two different points of view, a
desmodromic fully variable valve actuation mechanism while
[0008] FIGS. 4 to 11 show the same mechanism after a step by step
removal of various parts in order to reveal the inner parts,
[0009] FIG. 12 shows another embodiment of a desmodromic fully
variable valve actuation mechanism.
[0010] The mechanism shown in FIG. 1 derives from the mechanism
shown in the middle of FIG. 21 of U.S. 11759392 application.
[0011] In FIG. 1, the first control shaft 4 comprises two control
surfaces 51 and 52.
[0012] The roller (31, 32) is actuated by a rotating eccentric pin
158 through a connecting rod 155. The ring 32 rolls along the
control surface 52 and the pin 31 rolls along the control surface
51. The control surfaces 51 and 52 on the first control shaft 4,
allow the motion of the center 153 of the roller (31, 32) only
along the path 53 shown by dust dot line. The roller (31, 32) moves
in substantially simultaneous abutment to both surfaces 51 and 52.
Along a part of the path 53, the valve remains closed. It is the
lost motion part.
[0013] The valve 11 is properly secured to the actuator 10.
[0014] A washer 114 is between the valve 11 and the bottom side of
the actuator 10. A flexible washer 113 is at the upper side of the
bottom of the actuator 10, and a nut 112 is fastened on the thread
111 of the valve stem, providing preloading adjustment, known from
the art of desmodromic mechanisms.
[0015] Both control shafts can rotate about the axis at the cross
12. The second control shaft, not shown in FIG. 1, holds the center
156 of the lower pin of the rod 154 at a constant distance from the
axis at the cross 12 and displaces it angularly to increase or
decrease the valve lift. Rotating the first control shaft 4, the
valve duration and the valve lift change but not independently:
each valve lift is coupled to one and only valve duration and vice
versa. Changing the angular displacement of both control shafts,
the valve lift and the valve duration can vary independently.
[0016] In a four stroke engine, the eccentric pin can be secured on
a shaft rotating with half the crankshaft speed. The same shaft
with eccentric pins can serve all the intake valves of a cylinder
head or even all the intake and all the exhaust valves of a
cylinder head.
[0017] For applications where the simple Lost Motion VVA is
adequate, the mechanism can be simplified as shows FIG. 2, omitting
the two lower rods 9 and 154 and the second control shaft.
[0018] For friction reduction and minimization of the clearances,
the roller mentioned above can comprise pins, rings, needles, balls
etc known in the art.
[0019] The additional, beyond the conventional valve springs,
massive restoring springs necessary in most state of the art VVA
systems for the restoring of the parts of the VVA mechanism, and
the difficulty of their installation is a major problem and many
patents deal with it.
[0020] In the Desmodromic FVVA and VVA, there is no need of any
restoring springs, neither for the valves nor for the parts of the
VVA mechanism. The valves and the VVA parts move and restore to
their rest position desmodromically.
[0021] In FIG. 1 the eccentric pin 158 rotates about the axis 157.
The connecting rod 155 transfers the motion of the pin 158 to the
roller (31, 32). The roller is forced to move along a path formed
in the control shaft 4 by the control surfaces 51 and 52. The rod
152 is rotatably connected to the rod 155 at the axis 153. The rods
154 and 9 are rotatably connected to the rod 152 at the axis 151.
The pin 156 of the rod 154 is angularly displaceable, about the
axis at the cross 12, by the second control shaft. The lower end of
the rod 9 is rotatably connected, at the axis 150, to the valve
actuator 10. The valve actuator 10 holds the valve 11. As shown in
the detail at the right of FIG. 1, the cylindrical member 10 can
slide along a hole/bearing/guide 101. The valve 11 ends at a thread
111. A washer/height adjuster 114 is located between the valve 11
and the lower part of the bottom of the valve actuator 10. A
flexible washer 113 is located on the upper side of the bottom of
the valve actuator 10. The nut 112, fastened on the thread 111 of
the valve 11, preloads the flexible washer 113. The flexible washer
compensates for the thermal expansion and keeps the valve in secure
contact to the valve seat when the valve is at rest. The 114 washer
can also be flexible.
[0022] FIG. 3 shows the mechanism of FIG. 1 applied on a pair of
valves. Both control shafts are shown. In FIG. 4 the first control
shaft 4 is removed. In FIG. 5 the second control shaft is also
removed. In FIG. 6 the shaft with the eccentric pins is
removed.
[0023] In FIG. 7 the roller (31, 32) is removed. In FIG. 8 the
connecting rods 155 are removed. In FIG. 9 the rods 152 are
removed. FIG. 10 shows only the valves and the actuators. FIG. 11
shows in detail the connection of the valve 11 to the valve
actuator 10.
[0024] Locking the first control shaft at an angle, the system of
FIG. 1 to 11 becomes a Constant Duration Desmodromic VVA.
[0025] FIG. 12 shows a different embodiment of the desmodromic VVA
mechanism. The eccentric pin 158 displaces, via the connecting rod
155, the upper end of the rod 154. The lower end of the rod 154 is
displaceable about the axis at the cross 122 by a control shaft
similar to the second control shaft mentioned in the first
embodiment. The rod 152, rotatably connected to the rods 155 and
154, displaces the roller (31, 32). The roller (31, 32) is in
substantially simultaneous abutment to the two control surfaces 51
and 52 of the control shaft 4. The control shaft 4 is rotatable
about the axis at the cross 121. The roller (31, 32) displaces the
valve actuator 10 and the valve 11, via the rod 9. The system is a
FVVA and at the same time a desmodromic valve train, capable to
operate without valve spring and without any other restoring
springs for the parts of the VVA mechanism.
[0026] In the previous, the actuation of the VVA mechanism by a
rotating eccentric pin, through a connecting rod, was the case.
Several alternatives of the reciprocating pin, known from the art,
can be used instead, like the mechanism of the PCT/GR04/000052
application that provides linear reciprocation or the harmonically
reciprocating pin of the mechanism of the PCT/GR91/00004
application.
[0027] Although the invention has been described and illustrated in
detail, the spirit and scope of the present invention are to be
limited only by the terms of the appended claims.
* * * * *