GB2329219A

GB2329219A - Housing with integrated air inlet system and rocker cover for i.c. engine

Info

Publication number: GB2329219A
Application number: GB9820102A
Authority: GB
Inventors: Desclez Frederie; Priem Nico
Original assignee: Solvay SA
Current assignee: Solvay SA
Priority date: 1997-09-15
Filing date: 1998-09-15
Publication date: 1999-03-17
Anticipated expiration: 2018-09-15
Also published as: GB9820102D0; GB2329219B; DE19842234A1; FR2768464A1; GB9819780D0; BE1011453A3; FR2768464B1

Abstract

Air entering the inlet 2 of the housing 1 passes through filter 3 and butterfly valve 4 to a manifold 5 and thence to a number of outlets 6 each of which is connected to an engine cylinder by a tract 7. The lower side of the housing 1 has a recess 8, separated from the interior of the housing by a wall 9, which acts as the rocker cover. The butterfly valve 4 may be mounted on the side of the manifold 5 (fig. 3) for greater compactness. In another modification, fig.4, a computer 10 is fitted into the housing 1 and carries a pressure sensor 13 which is inserted into the manifold 5. The housing 1 may be moulded from thermoplastics. The number of parts to be assembled is reduced by the invention.

Description

Air inlet device for an internal combustion engine The present invention relates to an air inlet device for an internal combustion piston engine. These engines, commonly used in most vehicles such as cars and trucks, are usually supplied with air by an inlet system which is made up of several separate elements interconnected by means of pipes, such as, for example, an air filter intended to catch any dust, a throttle body intended to adjust the flow rate of air supplied to the engine, and a manifold intended to distribute the air to a number of inlet tracts supplying each of the engine cylinders with air. The fact that these elements are separate increases their cost and their total volume, makes their assembly complicated and increases the risk of leakages.

Furthermore, such engines generally comprise a part known as a rocker cover which isolates from the outside of the engine the cams which control the opening and closing of the inlet and exhaust valves, and other similar components. This rocker cover, conventionally fixed on the top of the engine, increases its overall volume. In order to remove any fuel and/or oil vapour that accumulates under the rocker cover while the engine is running, a pipe generally connects the rocker cover to the inlet system so that the said vapour can be burnt in the engine. This further increases the complexity of the inlet system.

With a view particularly to reducing the number of parts that have to be assembled during final assembly of vehicles that are equipped with an internal combustion piston engine, the present invention aims to provide an air inlet device which incorporates most of the essential elements of an air inlet system and also acts as a rocker cover.

Thus, a first subject of the present invention relates to a hermetic housing for an internal combustion piston engine air inlet device, comprising an air inlet orifice and a number of outlet orifices, the said housing being designed to accommodate, in particular, an air filter, a valve for regulating the air flow rate, and a manifold to which the outlet orifices are connected, the said housing comprising a lateral recess acting as an engine rocker cover.

This housing can be made of any appropriate material; advantageously, it is made essentially of at least one thermoplastic. The term thermoplastic should be understood as meaning any thermoplastic polymer or mixture of such polymers which may contain one or more additives such as lubricants, stabilizers, pigments, fillers or reinforcement materials, etc. It is preferable to use one or more polymers chosen from polyolefins, polyamides, polyphenylenesulphide, polyarylamides and polyphthalamides, and more particularly propylene polymers and polyamides. The thermoplastic or thermoplastics used may be employed using any appropriate technique, for example injection moulding. While it is advantageous for most of the housing to be made of at least one thermoplastic, this does not preclude the presence of special-purpose parts (inserts, screws, clips, springs, etc.) made of other materials, for example of one or more metals. The part of the housing that is made essentially of thermoplastic(s) is not necessarily a single piece. On the contrary, it is often preferable for it to be made by joining together (for example by bonding, welding, screwing or snap-fastening, etc.) several elemental parts.

The housing of the invention is intended to form the main element of an air inlet device for an internal combustion engine. Such a device is intended to distribute an air flow to the various cylinders of an engine, having, in particular, filtered it and regulated its flow rate. The air enters the device through the air inlet orifice and emerges therefrom via the outlet orifices, to which are connected tracts conveying the air to each of the cylinders of the engine. These tracts are generally fixed to the device removably (for example by screwing or clipping). The housing of the invention allows such a device to be produced easily, inexpensively, and with a small bulk.

To these ends, the housing of the invention is designed to accommodate the abovementioned members (air filter, etc.), that is to say that the housing is of an appropriate size and shape, and that it comprises attachment means (for example ribs, grooves, projections, screw threads, notches, inserts, etc.) allowing these members to be fastened into the housing. These attachment means may form an integral part of the housing or may have been attached to it after its manufacture, for example by welding or bonding. Likewise, the housing comprises partitioning means, subdividing, or allowing the subdividing of, its internal volume into various regions which are hermetically separated from one another (something which obviously does not preclude there being orifices or pipes providing a communication between some of these regions or between some of these regions and external members) . These partitioning means may, for example, consist of grooves or ribs to which plates may be attached later, for example by bonding or by welding.

One or more plates acting as partitioning means may also form an integral part of the housing.

In the case of engines which have a number of inlet valves per cylinder, it is possible to provide one outlet orifice and one tract for each inlet valve or alternatively to use tracts which split, allowing several inlet valves to be fed from one and the same outlet orifice. Advantageously, the housing comprises at least two outlet orifices for each cylinder, the various orifices corresponding to one and the same cylinder being connected thereto by tracts of differing lengths, together with a common (multi-way) shut-off member allowing the air to be forced to take a path, the length of which can be varied (but which is, however, identical for each cylinder at any given instant), for example as a function of the engine speed, under the control of a computer. If appropriate, this alternative form may apply to each inlet valve if each cylinder has several inlet valves.

The air filter may of any type, and constitutes a member which is well known in itself; it comprises, for example, a sheet of felt or a folded sheet of paper. To give it mechanical rigidity, the filter may be equipped with reinforcing elements, for example a metal or plastic mesh; the filter may also be set on a support placed in the housing or forming part thereof. To this end, it is advantageous for the housing to comprise a support intended to support the air filter. This support may, for example, consist of a peripheral rib or of a peripheral rim forming part of the wall of the housing. The air filter may be flat, longitudinally dividing the housing into an upstream part and a downstream part, with respect to the filter; it may just as easily be cylindrical (or have any topologically equivalent shape, for example that of a rectangular band) , the air inlet being, for example, via the centre of the cylinder. To allow easy replacement of the filter, the housing advantageously has a removable part, for example a screwed-on or clipped-on cover, giving access to the filter and which may also immobilize the latter by compressing it. To improve its effectiveness, the filter is often fitted with one or more seals preventing any lateral leakage.

If the air filter is large and if the air flow rate regulating valve is placed approximately opposite its centre, it may be advantageous for the valve - or more specifically one of its stationary parts, for example any length of pipe in which the shut-off member of the valve might be installed - to be equipped with one or more projections for supporting the filter at its centre.

The valve for regulating the air flow rate is preferably placed downstream of the air filter; it may be of any known type. In particular it is possible to use a butterfly valve, well known in the automotive field, comprising a rigid disc pivoting about a spindle and which can shut off an orifice through which the air has to pass. To this end, the housing advantageously comprises a wall separating the manifold from that part of the housing in which the air filter is installed, the said wall having an orifice capable of housing the valve.

As a preference, this orifice is extended by a length of pipe, in which the valve, or more precisely its shut-off member, that is to say its moving part, may be installed.

The valve is operated either directly, for example by an electromechanical operating member installed inside the housing (this member being electrically connected to a control circuit inside or outside the housing), or indirectly, for example by means of a linkage rod or a flexible cable connecting it mechanically to an external mechanism. The valve may also have additional characteristics well known in the field; in particular, it may comprise an idling bypass system.

The manifold, placed downstream of the air filter and of the regulating valve, is a simple volume which serves to distribute the air to the various outlet orifices, which open into it. Although in principle the air enters this manifold only via the aforementioned regulating valve, it is possible, for example, to provide an auxiliary inlet via which some of the exhaust gases (under the control of another valve) can be introduced into the manifold so that they can be combusted again (EGR (exhaust gas recirculation) function). Furthermore, it is also possible to equip the manifold with one or more tappings, that is to say one or more orifices allowing the manifold to communicate with other members outside the housing, for example to draw in petrol vapour from a canister associated with the fuel tank, or alternatively to measure the manifold depression, to transmit this depression to any fuel-pressure regulator, to supply a partial vacuum to a boosted braking system (master-VAC) or to an exhaust gas recirculation (EGR) valve, etc.

According to an advantageous alternative form, one of the walls of the manifold forms part of an external wall of the housing, and consists of a side plate which is fixed to the rest of the housing (for example by welding) that has already been manufactured.

This alternative form allows the injection moulding of a part (that can be released from the mould) to which merely such a side plate and a cover (allowing access to the air filter, as explained hereinabove) need be attached, in order to obtain the said housing.

The outlet orifices may possibly be equipped with lengths of pipe extending into the housing. This alternative form is advantageous insofar as, for fluid dynamics reasons (resonance etc.), it is often necessary to give the tracts a length longer than a certain threshold value, while at the same time limiting the space occupied by these tracts in the engine compartment. Furthermore, the outlet orifices may also possibly be equipped with lengths of pipe extending out of the housing, with a view, for example, to making it easier for the tracts to be connected at the time of final assembly.

The lateral recess of the housing acting as a rocker cover is of a shape and size that actually allows it to fulfil this function, that is to say to shelter the cams which open and close the engine valves, and other similar components. This recess needs to be substantially hermetic both from the inside and from the outside of the housing, or at the very least, the housing needs to be designed so as to allow such a hermetic recess to be created. To this end, the housing may comprise elements such as ribs or grooves, allowing a dividing plate to be attached thereto (for example by bonding or welding); alternatively, such a plate may just as easily form an integral part of the housing. Although the separation between the recess and the inside of the housing is described as being hermetic, it is, however, advantageous for the said recess to be connected to the manifold in such a way that the vapour that accumulates under the rocker cover while the engine is running is drawn into the manifold so that it can be burnt in the engine. This connection can be achieved using an appropriate pipe.

When the manifold is adjacent to the recess and is separated from it merely by a wall, this connection may easily be achieved by means of one or more simple orifices pierced in this wall. This wall may form an integral part of the housing or be attached thereto by welding, bonding, screwing or by a similar technique. It is advantageous for an oil interceptor to be inserted between the lateral recess and the manifold, to prevent oil droplets from being drawn into the manifold. Such an oil interceptor, which is well known in itself, may, in particular, comprise baffles. Furthermore, the housing may be equipped with a closable orifice allowing the sump (that is to say the cylinder head) of the engine to be filled with oil easily.

In a way known per se, the housing is equipped, generally at the periphery of the lateral recess that acts as a rocker cover, with means allowing the housing to be attached to an engine. These means may, in particular, consist of a holed flange allowing attachment using bolts. A gasket may advantageously be inserted between the housing and the engine.

Another subject of the present invention is an air inlet device for an internal combustion piston engine comprising a hermetic housing as described hereinabove, containing, in particular, an air filter, a valve for regulating the air flow rate, and a manifold to which the outlet orifices are connected, the said housing comprising a lateral recess acting as an engine rocker cover.

As a preference, the device also is essentially made of at least one thermoplastic, without precluding the presence of special-purpose parts (butterfly valve, inserts, screws, clips, springs, etc.) made of other materials, for example of metals.

Details regarding the air filter, the regulating valve and the manifold have been given hereinabove.

Apart from these various members, a computer which, in particular, controls the air flow rate regulating valve may advantageously be incorporated into the device, the said computer being equipped with a pressure sensor extending into the manifold and measuring the pressure therein. One of the advantages of this alternative form is that it makes it unnecessary to fit a separate pressure sensor in the manifold, and to connect it to the computer via a cable. The computer may, for example, be engaged in the housing via an orifice made in part of its wall that is common to the manifold, the computer being at least partially accessible from outside the said housing so that it can easily be connected to other members and/or extracted if need be.

In such a case, a gasket may be required. The computer may also be connected to one or more members internal to the device of the invention, for example to an electromechanical member for opening the air flow rate regulating valve.

The device described hereinabove meets the objectives listed at the beginning: it allows a reduction in the number of parts that make up the inlet system of an internal combustion engine, and this leads to a saving in weight and volume (and hence a lower cost) and to quicker final fitting on the engine.

Another object of the present invention therefore relates to an internal combustion piston engine with which there is associated an air inlet device as defined hereinabove, also acting as a rocker cover, and the outlet orifices of which are connected to the cylinders of the engine by tracts.

The inlet orifice through which the air enters, may open directly to the open air; it may just as easily be connected by a pipe to the outlet of another member placed upstream, such as a soundproofing member for example.

DESCRIPTION OF THE DRAWINGS The appended figures provide a non-limiting illustration of various alternative forms of the invention, which have been produced by way of example.

Figure 1 depicts diagrammatically and in elevation, a section through a device in accordance with the invention. Figure 2 depicts a section through the same device, seen in profile. Figures 3 and 4 depict, as sections seen in profile, other devices in accordance with the invention. These figures are diagrammatic and do not depict all the embodiment details; for example, they do not describe the details as to how the tracts are connected to the outlet orifices (by snap-fastening or screwing, etc.).

The device comprises a housing (1) made of thermoplastic, which the air enters via an air inlet orifice (2). The air is first of all filtered by an air filter (3); it then passes through a butterfly valve (4) allowing its flow rate to be regulated (and the control mechanism of which is not depicted) and then reaches a manifold (5) with four outlet orifices (6), each connected to one cylinder of the engine (not depicted) by a tract (7). In Figure 2, it can be seen that these tracts extend into the manifold in the form of lengths of pipe.

This device is intended to be mounted on an internal combustion piston engine; to this end, a recess (8) made on the lower side of the housing (1) and separated from the inside of the housing (1) by a wall (9), acts as an engine rocker cover, allowing the cams which control the valves of the engine and/or other similar components to be isolated from the external environment.

The device in Figure 3 is particularly compact by virtue of the fact that the butterfly valve (4) is arranged to the side of the manifold (5) rather than on top of it, this making it possible to reduce the overall height of the device. Also depicted in Figure 3 is an oil interceptor (12), inserted between the recess (8) and the manifold (5).

In Figure 4, the device of the invention is equipped with a computer (10) inserted in an orifice made in the exterior wall of the housing (and held in place by means which have not been depicted) and comprising a sensor (13) extending into the manifold (5) and allowing the pressure therein to be measured. Gaskets seal the housing and the manifold. (The computer obviously does not extend over the entire length of the device - at right angles to the plane of the figure - otherwise the air would not be able to flow from the air filter to the manifold).

That wall of the housing in which the outlet orifices (6) are made is not common to the manifold, and a length of pipe (11) connects each outlet orifice (6) to the manifold (5). In plan view, these lengths of pipe (11) are arranged on each side of the valve (4). Furthermore, the axes of these lengths of pipe (11) are in the plane of the internal wall (9) that separates the lateral recess (8) from the interior space of the housing, in which the air flows. These lengths therefore form semicylindrical protrusions which are parallel in each of these two regions.

The side wall of the manifold which is common to the exterior wall of the housing consists of a plate (14) welded thereto, and the top wall (15) of the housing is removable, in particular allowing easy replacement of the filter. It will be noted that, with the exception of these two elements (14-15) which are attached later, the remaining part of the housing constitutes a single part which has been injection-moulded in a single operation, using a moulding rig comprising: c a bottom ram, which can move vertically, which was used to form the lateral recess (8) and the bottom surface of the internal wall (9), including the (semi cylindrical) bottom walls of the lengths of pipe (11), - a right-hand side ram, which can move horizontally, which was used to form the manifold (5), including its orifice into which the flow rate regulating valve (4) will be fixed, and the bottom surface of the lengths of pipe (11) connecting the manifold (5) to the outlet orifices (6), and - a top ram, which can move vertically, which was used to form the remainder of the interior space of the housing (including, in particular, the air filter housing) and the top surface of the internal wall (9), including the (semi-cylindrical) top walls of the lengths of pipe (11) Once this part had been moulded, the air filter, the air flow rate regulating valve (including the length of pipe in which it is placed and its control device) and the other accessories needed for the operation of the device were mounted in it. The orifices providing communication between certain regions of the housing or between certain regions of the housing and the outside were also pierced. The manifold (5) was then definitively sealed with respect to the outside of the housing by welding the plate (14) thereto, the cover (15) was attached to the housing, and the computer (10) was inserted in its housing.

Claims

1. Hermetic housing for an internal combustion piston engine air inlet device, comprising an air inlet orifice and a number of outlet orifices, the said housing being designed to accommodate, in particular, an air filter, a valve for regulating the air flow rate, and a manifold to which the outlet orifices are connected, the said housing comprising a lateral recess acting as an engine rocker cover.

2. Housing according to Claim 1, made essentially of at least one thermoplastic.

3. Housing according to one of the preceding claims, comprising a support intended to support the air filter

4. Housing according to one of the preceding claims, comprising a wall separating the manifold from that part of the housing in which the air filter is installed, the said wall having an orifice capable of housing the valve.

5. Housing according to one of the preceding claims, in which the lateral recess acting as a rocker cover is connected to the manifold in such a way that the vapour that accumulates under the rocker cover while the engine is running is drawn into the manifold so that it can be burnt in the engine.

6. Housing according to the preceding claim, in which an oil interceptor is inserted between the lateral recess and the manifold.

7. Air inlet device for an internal combustion piston engine comprising a hermetic housing according to one of the preceding claims, containing, in particular, an air filter, a valve for regulating the air flow rate, and a manifold to which the outlet orifices are connected, the said housing comprising a lateral recess acting as an engine rocker cover.

8. Device according to the preceding claim, into which there is incorporated a computer which, in particular, controls the air flow rate regulating valve, the said computer being equipped with a pressure sensor extending into the manifold and measuring the pressure therein.

9. Internal combustion piston engine with which there is associated an air inlet device according to one of the two preceding claims, also acting as a rocker cover, and the outlet orifices of which are connected to the cylinders of the engine by tracts.

10. A hermetic housing for an internal combustion piston engine air inlet device substantially as hereinbefore described with reference to Figures 1 and 2 or 3 or 4.