WO2019010472A1

WO2019010472A1 - Valvetrain support structure with integrated wiring

Info

Publication number: WO2019010472A1
Application number: PCT/US2018/041180
Authority: WO
Inventors: James Edward Mccarthy, Jr.; David Gerard Genise
Original assignee: Eaton Intelligent Power Limited
Priority date: 2017-07-07
Filing date: 2018-07-09
Publication date: 2019-01-10

Abstract

A valvetrain that includes an electronic device and a rocker arm assembly and is suitable for an internal combustion engine that includes a combustion chamber, a moveable valve having a seat formed within the combustion chamber, and a camshaft. The rocker arm assembly may include a rocker arm and a cam follower configured to engage a cam on the camshaft as the camshaft rotates. The electronic device may be mounted on the rocker arm. Wiring for the electronic device is attached along a length of or passes through a structural component that supports a part of the valvetrain. The structural component may be a part of the valvetrain. The wiring may be provided by the valvetrain manufacturer rather than left to an engine manufacturer.

Description

VALVETRAIN SUPPORT STRUCTURE WITH INTEGRATED WIRING

Field

[0001] The present teachings relate to valvetrains, particularly valvetrains providing variable valve lift (WL) or cylinder deactivation (CDA).

Background

[0002] Hydraulically actuated latches are used on some rocker arm assemblies to implement variable valve lift (WL) or cylinder deactivation (CDA). For example, some switching roller finger followers (SRFF) use hydraulically actuated latches. In these systems, pressurized oil from an oil pump may be used for latch actuation. The flow of pressurized oil may be regulated by an oil control valve (OCV) under the supervision of an Engine Control Unit (ECU). A separate feed from the same source provides oil for hydraulic lash adjustment. This means that each rocker arm has two hydraulic feeds, which entails a degree of complexity and equipment cost. The oil demands of these hydraulic feeds may approach the limits of existing supply systems.

[0003] Using electromechanical latch assemblies instead of hydraulically- actuated latches can reduce complexity and demands for oil in some valvetrain systems. Electromechanical latch assemblies create the need to provide electrical power to valvetrain system components. Valvetrain electrical power is also desirable for devices that could provide on board diagnostic information for cylinder

deactivating and switching rocker arm assemblies.

Summary

[0004] The present teachings relate to a valvetrain suitable for an internal combustion engine that includes a combustion chamber, a moveable valve having a seat formed within the combustion chamber, and a camshaft. The valvetrain includes an electronic device and a rocker arm assembly. The rocker arm assembly may include a rocker arm and a cam follower configured to engage a cam on the camshaft as the camshaft rotates. The electronic device may be mounted on the rocker arm assembly. In accordance with the present teachings, wiring for the electronic device is attached along a length of or passes through a structural component that supports a part of the valvetrain. The structural component may be a part of the valvetrain. Valvetrains are often purchased by an engine manufacturer. A valvetrain in accordance with the present teachings allows the valvetrain manufacturer to provide wiring that an engine manufacturer might otherwise be required to install. The wiring may terminate at a connection plug through which a plurality of valvetrain electronic devices may be coupled to a vehicle's electrical system.

[0005] The number of wires to be connected may be reduced using a common ground. In some aspects of the present teachings, the electronic device is grounded through the engine. In some of these teachings, the electronic device is grounded through the rocker arm assembly. In some of these teachings, the electronic device is grounded through a structural component of the valvetrain. In some of these teachings, the valvetrain includes a plurality of the electronic devices, each associated with a distinct rocker arm assembly, and the wiring includes a common ground for all the electrical devices.

[0006] In some of these teachings, the structural component is selected from the group consisting of a camshaft carrier, a valvetrain carrier, and a camshaft journal. In some of these teachings, the wiring follows a pathway determined by the shape of the structural component. In some of these teachings, the wiring is adhered to the structural component. In some of these teachings, the wiring is embedded within the structural component. In some of these teachings, the wiring passes through the structural component. In some of these teachings, filler secures the wiring in position within the structural component. In some of these teachings, a wire is attached to the structural component at three or more locations along the pathway. In some of these teachings, the wire is attached to the structural component at five or more locations along the pathway.

[0007] In some of these teachings, the electronic device is an electromechanical latch assembly. The electromechanical latch assembly may include a latch pin and an electrical coil. The electrical coil may be mounted on a rocker arm of the rocker arm assembly. Alternatively, the electronic device may be a sensor that provides information useful for diagnostic or control operations.

[0008] In some aspects of the present teachings, the structural component has an engine-internal side and an engine-external side. The wiring enters the structural component on the engine-internal side exits the structural component on the engine- external side. In these teachings, the structural component provides an interface through which the wiring passes from inside the engine to outside the engine.

[0009] Some aspects of the present teachings relate to a method of installing a valvetrain. In some of these teachings, the wiring is attached to the structural component and the structural component together with the wiring is installed in an engine. In some of these teachings, the wiring is enclosed within the structural component and the structural component together with the wiring is installed in an engine. In some of these teachings, the wiring is threaded through the structural component and the structural component together with the wiring is installed in an engine. These methods allow the valvetrain manufacturer to complete most of the wiring for any electronic devices that are provided with the valvetrain.

[0010] The primary purpose of this summary has been to present certain of the inventors' concepts in a simplified form to facilitate understanding of the more detailed description that follows. This summary is not a comprehensive description of every one of the inventors' concepts or every combination of the inventors' concepts that can be considered "invention". Other concepts of the inventors will be conveyed to one of ordinary skill in the art by the following detailed description together with the drawings. The specifics disclosed herein may be generalized, narrowed, and combined in various ways with the ultimate statement of what the inventors claim as their invention being reserved for the claims that follow.

Brief Description of the Drawings

[0011] Fig. 1 is a perspective view of a portion of a valvetrain according to some aspects of the present teachings, the portion of the valvetrain including a camshaft carrier.

[0012] Fig. 2 illustrates the valvetrain of Fig. 1 with additional parts.

[0013] Fig. 3 is a perspective view of a rocker arm assembly for the valvetrain of

Fig. 1 .

[0014] Fig. 4 is a partial view illustrating a portion of the valvetrain of Fig. 1 in greater detail. Detailed Description

[0015] Figs. 1 and 2 illustrates some components of a valvetrain 100 in

accordance with the present teachings. As illustrated in Fig. 1 , valvetrain 100 includes a camshaft carrier 101 and a plurality of camshaft journals 102. Fig. 2 shows valvetrain 100 with additional components, including a camshaft 103 with cams 104, valves 105, and rocker arm assemblies 106.

[0016] With reference to Fig. 3, rocker arm assembly 106 includes a cam follower

1 12 mounted to an inner arm 1 10 and an electromagnetic latch assembly 107 mounted to an outer arm 1 1 1 . Electromagnetic latch assembly 107 includes a latch pin 108 and an electrical coil 109. Electrical coil 109 is operable to actuate latch pin 108 between engaging and non-engaging positions.

[0017] Electrical coils 109 are mounted on outer arms 1 1 1 , which move in proximity to camshaft carrier 101 . Fig. 4 illustrates wiring 1 13 that may be

embedded within camshaft carrier 101 to bring power to outer arms 1 1 1 . Wiring 1 13 enters camshaft carrier 101 through an aperture 1 14 on an outer side 1 15 of camshaft carrier 101 . Outer side 1 15 could be made an engine-external side of camshaft carrier 101 . Wires 1 13 exit camshaft carrier 101 through apertures 1 16 and 1 17, which are on engine-internal sides of camshaft carrier 101 and place wires

1 13 in proximity to coils 109. A foam, a thermoplastic, or a thermosetting polymer may be used to secure wires 1 13 within camshaft carrier 101 .

[0018] With reference to Fig. 4, wire 1 13A is supported along a length 120 of camshaft carrier 101 that runs parallel to camshaft journal 102 by being embedded in camshaft carrier 101. Wire 1 13A may also be supported to camshaft carrier 101 along length 120 while be external to camshaft carrier 101 . In some embodiments, the support along length 120 is provided by a strip of adhesive. In some

embodiments, the support along length 120 is provided by mechanical fasteners. Preferably, three or more fasteners would be used to cause wire 1 13A to follow a pathway determined by the shape of camshaft carrier 101 , particularly if following the pathway determined by the shape of camshaft carrier 101 involves making one or more turns. More preferably, five or more fasteners would be used.

[0019] Outer arms 1 1 1 reciprocate rapidly relative to camshaft carrier 101 . The connection between wires 1 13 and coils 109 may require unconventional wiring. As an alternative to wiring, power transfer between wires 1 13 and coils 109 may occur by any of the following means: springs functioning as wires, inductive power transfer, electrical connections between surfaces that slide one across the other. Sliding contact may be sustained by brushes or spring-loaded contacts. The ends of wires 1 13 that are distal from coils 109 wiring may terminate at a connection plug (not shown) through which coils 109 may be coupled to a vehicle's electrical system.

[0020] In electromagnetic latch assembly 107, latch pin 108 is stable

independently from electrical coil 109 in both engaging and non-engaging positions. Energized with a DC current in a first direction, electrical coil 109 is operable to actuate latch pin 109 from the engaging to the non-engaging position. Energized with a DC current in a reverse of the first direction, electrical coil 109 is operable to actuate latch pin 109 from the non-engaging position to the engaging position. If electrical coil 109 is to be grounded through rocker arm assembly 106 or if a plurality of electrical coils 109 are to share a common ground, the vehicle's electrical system should be equipped to selectively provide wires 1 13, other than ground wires, to potentials either above or below ground.

[0021] The components and features of the present disclosure have been shown and/or described in terms of certain embodiments and examples. While a particular component or feature, or a broad or narrow formulation of that component or feature, may have been described in relation to only one embodiment or one example, all components and features in either their broad or narrow formulations may be combined with other components or features to the extent such combinations would be recognized as logical by one of ordinary skill in the art.

Claims

The claims are:

1 . A valvetrain for an internal combustion engine of a type that has a combustion chamber and a moveable valve having a seat formed in the combustion chamber, the valvetrain comprising:

a camshaft;

a rocker arm assembly configured to actuate a moveable valve and comprising a rocker arm and a cam follower configured to engage a cam mounted on the camshaft as the camshaft rotates;

an electronic device; and

a structural component that supports a part of the valvetrain;

wherein wiring for the electronic device is attached along a length of or passes through the structural component.

2. A valvetrain according to claim 1 , wherein the electronic device is mounted on a rocker arm of the rocker arm assembly.

3. A valvetrain according to claim 1 , wherein the structural component is selected from the group consisting of a camshaft carrier, a valvetrain carrier, and a camshaft journal.

4. A valvetrain according to claim 1 , wherein the wiring follows a pathway determined by the shape of the structural component.

5. A valvetrain according to claim 1 , wherein the wiring is adhered to the structural component.

6. A valvetrain according to claim 1 , wherein the wiring is embedded within the structural component.

7. A valvetrain according to claim 1 , wherein the wiring passes through the structural component.

8. A valvetrain according to claim 7, wherein a filler secures the wiring in position within the structural component.

9. A valvetrain according to claim 7, wherein:

the structural component has an engine-internal side and an engine-external side;

the wiring enters the structural component on the engine-internal side; and the wiring exits the structural component on the engine-external side.

10. A valvetrain according to any one of claims 1 to 9, wherein the electrical device is grounded to the engine.

1 1 . A valvetrain according to any one of claims 1 to 9, wherein the electrical device is grounded through the rocker arm assembly.

12. A valvetrain according to any one of claims 1 to 9, wherein:

the valvetrain comprises a plurality of electrical devices each associated with a distinct rocker arm assembly;

the wiring includes a common ground for all of the electrical devices.

13. A method of manufacturing an engine with a valvetrain according to any one of claims 1 to 9, the method comprising:

attaching the wiring to the structural component; and

installing the structural component with the wiring in the engine.

14. A method of manufacturing an engine with a valvetrain according to any one of claims 1 to 9, the method comprising:

enclosing the wiring within the structural component; and

installing the structural component with the wiring in the engine.

15. A method of manufacturing an engine with a valvetrain according to any one of claims 1 to 9, the method comprising: threading the wiring through the structural component; and installing the structural component with the wiring in the engi