U.S. patent application number 10/065136 was filed with the patent office on 2003-03-27 for electromagnetic system to control the valves of an engine.
This patent application is currently assigned to Magneti Marelli Powertrain S.p.A.. Invention is credited to Cristiani, Marcello, Morelli, Nicola.
Application Number | 20030056743 10/065136 |
Document ID | / |
Family ID | 11439615 |
Filed Date | 2003-03-27 |
United States Patent
Application |
20030056743 |
Kind Code |
A1 |
Cristiani, Marcello ; et
al. |
March 27, 2003 |
Electromagnetic system to control the valves of an engine
Abstract
Electromagnetic system to control the valves of an engine and
having a control unit and for each valve a respective
electromagnetic actuator provided with a pair of electromagnets;
each electromagnet has a winding which is provided with a power
bobbin and an auxiliary measurement bobbin, and a flexible
connection cable, which is directly integrated in the respective
winding in order to connect the winding itself to the control unit
electrically without further interpositions.
Inventors: |
Cristiani, Marcello; (Imola,
IT) ; Morelli, Nicola; (Rende, IT) |
Correspondence
Address: |
CARTER WHITE
HOWREY SIMON ARNOLD AND WHITE LLP
750 BERING DRIVE
HOUSTON
TX
77057
US
|
Assignee: |
Magneti Marelli Powertrain
S.p.A.
Corso Ferrucci, 112/A
Torino
IT
10138
|
Family ID: |
11439615 |
Appl. No.: |
10/065136 |
Filed: |
September 19, 2002 |
Current U.S.
Class: |
123/90.11 |
Current CPC
Class: |
F01L 2009/2109 20210101;
F01L 9/20 20210101 |
Class at
Publication: |
123/90.11 |
International
Class: |
F01L 009/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 20, 2001 |
IT |
BO2001A000570 |
Claims
1. Electromagnetic system to control the valves (2) of an engine
and comprising a control unit (11) and for each valve (2) a
respective electromagnetic actuator (1) provided with a pair of
electromagnets (8), with an actuator body (4), which is connected
mechanically to the respective valve (2) and is fitted such as to
be mobile between the two electromagnets (8) in order to be
displaced under the action of the electromagnets (8) themselves,
and with at least one resilient body (9), which is connected to the
actuator body (4) in order to maintain the actuator body (4) itself
in an intermediate position of rest between the two electromagnets
(8); each electromagnet (8) comprising a magnetic core (12), a
winding (17), which is connected to the magnetic core (12) and is
provided with a power bobbin (13) and an auxiliary measurement
bobbin (16), and a connection cable (18), which can connect the
winding (17) electrically to the control unit (11); the
electromagnetic system being characterised in that each said
electromagnet (8) comprises a respective flexible connection cable
(18), which is integrated directly in the respective winding (17)
in order to connect the winding (17) itself to the control unit
(11) electrically without further interpositions:
2. System according to claim 1, wherein each said connection cable
(18) comprises four electrical conductors (19) inserted in a single
isolating sheath (21) in order to connect both the respective power
bobbin (13) and the respective auxiliary measurement bobbin (16)
electrically to the said control unit (11).
3. System according to claim 2, wherein the said four electrical
conductors (19) of a single connection cable (18) are the same
electrical conductors as those used for production of the power
bobbin (13) and of the auxiliary bobbin (16) of the respective
winding (17).
4. System according to claim 3, wherein each said connection cable
(18) comprises further electrical isolations which are accommodated
inside the respective sheath (21).
5. System according to claim 1, and comprising a box-type body (20)
which can accommodate a pair of said electromagnetic actuators (1)
for the control of two respective said valves (2); the said
box-type body (20) having four through holes for passage of the
corresponding said connection cables (18).
6. Electromagnetic actuator to control the valve (2) of an engine;
the electromagnetic actuator (1) comprising a pair of
electromagnets (8), an actuator body (4), which is connected
mechanically to the valve (2) and is fitted such as to be mobile
between the two electromagnets (8) in order to be displaced under
the action of the electromagnets (8) themselves, and at least one
resilient body (9), which is connected to the actuator body (4) in
order to maintain the actuator body (4) itself in an intermediate
position of rest between the two electromagnets (8); each
electromagnet (8) comprising a magnetic core (12), a winding (17),
which is connected to the magnetic core (12) and is provided with a
power bobbin (13) and an auxiliary measurement bobbin (16), and a
connection cable (18), which can connect the winding (17)
electrically to the control unit (11); the electromagnetic actuator
(1) being characterised in that each said electromagnet (8)
comprises a respective flexible connection cable (18), which is
integrated directly in the respective winding (17) in order to
connect the winding (17) itself electrically to the control unit
(11) without further interpositions.
Description
BACKGROUND OF INVENTION
[0001] The present invention relates to an electromagnetic system
to control the valves of an engine.
[0002] As is known, internal combustion engines are currently at
the experimental stage, in which the intake and discharge valves
are moved by electromagnetic actuators (of the type described in
European patent application EP1087110). These electromagnetic
actuators have undoubted advantages, since they make it possible to
control each valve according to an optimised law for any operative
condition of the engine, whereas the conventional mechanical
actuators (typically cam shafts) require definition of a raising
profile of the valves which represents an acceptable compromise for
all the possible operating conditions of the engine.
[0003] An electromagnetic actuator for a valve of an internal
combustion engine of the above-described type normally comprises an
actuator body, which is connected to the rod of the valve and in
conditions of rest is maintained by at least one spring in an
intermediate position between two de-excited electromagnets; in
use, the electromagnets are controlled by a control unit such as to
exert alternately a force of attraction of magnetic origin on the
actuator body in order to displace the actuator body itself between
the two end stop positions, which correspond to a position of
maximum opening and of closure of the respective valve.
SUMMARY OF INVENTION
[0004] The object of the present invention is to provide an
electromagnetic system to control the valves of an engine, which
has an electrical connection between the control unit and each
electromagnet and is easy and economical to implement.
[0005] According to the present invention, an electromagnetic
system to control the valves of an engine is provided, comprising a
control unit and for each valve a respective electromagnetic
actuator provided with a pair of electromagnets, an actuator body,
which is connected mechanically to the respective valve and is
fitted such as to be mobile between the two electromagnets in order
to be displaced under the action of the electromagnets themselves,
and at least one resilient body, which is connected to the actuator
body in order to maintain the actuator body itself in an
intermediate position of rest between the two electromagnets; each
electromagnet comprising a magnetic core, a winding, which is
connected to the magnetic core and is provided with a power bobbin
and an auxiliary measurement bobbin, and a connection cable, which
can connect the winding electrically to the control unit; the
electromagnetic system being characterised in that each said
electromagnet comprises a respective flexible cable, which is
directly integrated in the respective winding in order to connect
the respective winding electrically to the control unit without any
further interpositions.
BRIEF DESCRIPTION OF DRAWINGS
[0006] The present invention will now be described with reference
to the attached drawings, which illustrate a non-limiting
embodiment of it, in which:
[0007] FIG. 1 is a schematic view in lateral elevation and
partially in cross-section of a valve of an engine and of a
corresponding electromagnetic actuator;
[0008] FIG. 2 illustrates schematically an electromagnetic circuit
of the actuator in FIG. 1; and
[0009] FIG. 3 is a view in cross-section of a support structure
containing a pair of electromagnetic actuators produced according
to the present invention.
DETAILED DESCRIPTION
[0010] In FIG. 1, 1 indicates as a whole an electromagnetic
actuator (of the type described in patent application EP1087110)
connected to an intake or discharge valve 2 of an internal
combustion engine of a known type in order to displace the valve 2
itself along a longitudinal axis 3 of the valve between a position
of closure (which is known and not illustrated) and a position of
maximum opening (which is known and not illustrated).
[0011] The electromagnetic actuator 1 comprises an oscillating arm
4 which is made at least partially of ferromagnetic material, which
has a first end pivoted on a support 5 such as to be able to
oscillate around an axis 6 of rotation which is transverse to the
longitudinal axis 3 of the valve 2, and a second end which is
connected by means of a hinge 7 to an upper end of the valve 2. The
electromagnetic actuator 1 also comprises two electromagnets 8
which are supported in a fixed position by the support 5 such as to
be disposed on opposite sides of the oscillating arm 4, and a
spring 9 which is connected to the valve 2 and can maintain the
oscillating arm 4 in an intermediate position (illustrated in FIG.
1) in which the oscillating arm 4 itself is equidistant from the
pole pieces 10 of the two electromagnets 8. According to a
different embodiment not illustrated, the spring 9 which is
connected to the valve 2 is flanked or replaced by a torsion-bar
spring which is connected to the hinge which is present between the
support 5 and the oscillating arm 4.
[0012] In use, the control unit 11 controls with feedback and
substantially in a known manner the position of the oscillating arm
4, i.e. the position of the valve 2, on the basis of the operating
conditions of the engine; in particular, the control unit 11
excites the electromagnets 8 with a respective electric current
i(t) in order to exert alternately or simultaneously a force of
attraction of magnetic origin on the oscillating arm 4, such as to
make the oscillating arm 4 itself rotate around the axis 6 of
rotation, consequently displacing the valve 2 along the respective
longitudinal axis 3 and between the said positions of maximum
opening and closure (not illustrated).
[0013] As illustrated in FIG. 1, the valve 2 is in the said
position of closure (not illustrated) when the oscillating arm 4
abuts the excited upper electromagnet 8, it is in the said position
of maximum opening (not illustrated) when the oscillating arm 4
abuts the excited lower electromagnet 8, and is in a position of
partial opening when the two electromagnets 8 are both switched off
and the oscillating arm 4 is in the said intermediate position
(illustrated in FIG. 1) owing to the effect of the force exerted by
the spring 9.
[0014] As illustrated in FIG. 2, each electromagnet 8 comprises a
respective magnetic core 12 which is connected to a corresponding
bobbin 13, which is supplied by the control unit 11 with a current
i(t) which is variable over a period of time in order to generate a
flow .phi. (t) through a respective magnetic circuit 14 which is
connected to the bobbin 13. In particular, each magnetic circuit 14
consists of the corresponding core 12 of ferromagnetic material,
the oscillating arm 4 of ferromagnetic material and the gap 15
which exists between the corresponding core 12 and the oscillating
arm 4.
[0015] To each magnetic core 12 there is connected a further,
auxiliary bobbin 16 (consisting of at least one coil and provided
with a number Na of coils) connected to a measurement circuit
(which is known and not illustrated) of the control unit 11, which
can measure in real time the value of the flow .phi. (t) through
the corresponding magnetic circuit 14.
[0016] In particular, a voltmeter is connected to the terminals of
the auxiliary bobbin 16; since the terminals of the auxiliary
bobbin 16 are substantially open (the internal resistance of the
voltmeter is high enough to be able to be considered infinite
without introducing appreciable errors), no current passes through
the auxiliary bobbin 16 and the voltage at its terminals depends
solely on the derivative of the flow .phi. (t) over a period of
time, from which it is possible to determine the value of the flow
.phi. (t) by means of an operation of integration.
[0017] In the practical embodiment, in an electromagnet 8 the
respective bobbin 13 and the respective auxiliary bobbin 16 are
wound together in a single winding 17 in order to simplify both the
production of the bobbins 13 and 16 themselves, and their
connection to the corresponding magnetic core 12. In addition, each
electromagnet 8, or rather each winding 17, must be connected to
the control unit 11 by means of a respective connection cable 18
which is provided with four independent electrical conductors 19
(two for circulation of the current i(t), and two for measurement
of the voltage at the ends of the auxiliary bobbin 16).
[0018] As illustrated in FIG. 3, in order to be able to install the
electromagnetic actuators 1 of the type previously described, use
is preferably made of a box-type body 20, which accommodates two
electromagnetic actuators 1 which can control respective valves 2.
In particular, the box-type body 20 is preferably used in order to
control the two intake or discharge valves 2 of a single cylinder
(not illustrated) in an internal combustion engine which has four
valves per cylinder, since in these engines the two intake or
discharge valves 2 of a single cylinder are disposed in positions
which are relatively very close to one another.
[0019] Each winding 17 comprises a respective flexible connection
cable 18, which is integrated directly in the winding 17 itself and
comprises four electrical conductors 19 which are inserted in a
single insulating sheath 21. In particular, the connection cable 18
is not added to the winding 17 after production of the winding 17
itself, but is formed during production of the winding 17 by using
as electrical conductors 19 the same conductors used for production
of the winding 17 (thus eliminating the need to produce electrical
junctions). Optionally, further isolations can be added to the
electrical conductors 19 inside the sheath 21, in particular in
order to separate the two electrical power conductors 19 (via which
the current i(t) circulates) from the two electrical signal
conductors 19 (via which the voltage is measured at the ends of the
auxiliary bobbin 16).
[0020] For each electromagnet 8, the box-type body 20 comprises a
respective through hole 22, through which the respective connection
cable 18 is passed, such as to permit connection of the connection
cable 18 itself to the control unit 11.
[0021] In order to connect the cable 18 electrically to the control
unit 11, the end portions of the respective electrical conductors
19 can be inserted in connection terminals (not shown) of the
control unit 11, or the end portions of the respective electrical
conductors 19 can be inserted in a detachable connector (which is
known and not illustrated) in order to permit fast connection
to/disconnection from the control unit 11.
[0022] The fact of using for each electromagnet 8 a respective
single connection cable 18 which is integrated directly in the
corresponding winding 17 makes it possible to produce the
connection of the electromagnet 8 to the control unit 11 simply (by
simplifying both the structure and the fitting of the
electromagnetic actuators 1), economically, and with reduction of
the problems of electrical connection (since, as the connection
cable 18 is flexible it can be adapted to various paths).
[0023] While the apparatus, compositions and methods of this
invention have been described in terms of preferred or illustrative
embodiments, it will be apparent to those of skill in the art that
variations may be applied to the process described herein without
departing from the concept and scope of the invention. All such
similar substitutes and modifications apparent to those skilled in
the art are deemed to be within the scope and concept of the
invention as it is set out in the following claims.
* * * * *