GB2371787A

GB2371787A - Engine air intake duct with valve closing main air inlet to prevent water ingestion

Info

Publication number: GB2371787A
Application number: GB0102760A
Authority: GB
Inventors: Steen Mccollin; Nathan Martin Bone; David Andrew Hailes
Original assignee: Land Rover Group Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2001-02-05
Filing date: 2001-02-05
Publication date: 2002-08-07
Anticipated expiration: 2021-02-05
Also published as: GB0102760D0; GB2371787B

Abstract

In a motor vehicle an engine intake duct has a main air inlet including a flow sensitive main inlet valve 17. The valve 17 has a flap 31 connected by a flexure hinge 32 to a wall of the duct. If the vehicle encounters a flood, water attempting to enter the duct will cause the flap 31 to pivot upwards and the valve 17 to close. The closing of the main air inlet allows suction from the engine to open an auxiliary air inlet (Fig. 7) to ensure that the engine remains running. There may be two valve-controlled main air inlets.

Description

Air Intake Duct

This invention relates to air intake ducts for internal combustion engines on motor vehicles. Such ducts are provided to duct cold air, usually from a front region of the vehicle, to an air filter and thence to the engine. A problem with such ducts is that it is not uncommon for fords or floods to be encountered, particularly where such vehicles are intended for off-road use. Unfortunately, a vehicle which travels through a ford or flood at any appreciable speed tends to create a bow-wave at the front which is usually in the region of the main air inlet for the duct. If water is taken from there into the engine then this can have disastrous results. Since water is incompressible, the engine can be brought to an abrupt halt by water in one of the combustion chambers and mechanical damage is inevitable.

Various attempts have been made to avoid the problem of water ingestion.

The problem essentially involves preventing the inflow of water and the provision of an alternative intake for the supply of air. However, such earlier attempts have tended to address each of these problems on a piecemeal basis and have overlooked a further problem which relates to the momentum of any water which is ingested into the air intake. The present invention aims to provide a novel solution to such a problem.

In accordance with one aspect of the invention there is provided an air intake duct for an internal combustion engine in a motor vehicle, the duct including a main inlet for the entry of air into the duct, an outlet for the transfer of air from the duct to the engine and an auxiliary inlet for the entry of air into the duct downstream of the main inlet, the main inlet being at the upstream end of the duct and comprising a flow sensitive main inlet valve which in use is normally open to allow the passage of air into the duct but closes to prevent the entry of water into the duct and the auxiliary inlet being controlled by an auxiliary inlet valve which

is normally closed but is operational to open when the main inlet is closed by the main inlet valve.

Preferably, the main inlet valve comprises a main inlet valve member having an impact surface, the main valve member being normally biased into an open position and being closed by the momentum of water approaching the main inlet acting on the impact surface. Conveniently, the main inlet valve member is biased by gravity into the open position. The main inlet valve member may comprise a pivoted flap which may be hinged about one edge thereof. The main inlet valve member may be spring biased into the open position.

Preferably, when the duct is installed in a motor vehicle, the main inlet faces away from the normal direction of travel. When the main inlet valve member comprises a pivoted flap hinged about one edge thereof as previously referred to, said one edge of the pivoted flap is preferably leading relative to the main inlet in the normal direction of travel.

The auxiliary inlet valve may conveniently comprise a spring loaded auxiliary valve member which is spring loaded into the closed position.

In accordance with another aspect of the invention there is provided a motor vehicle having an internal combustion engine and an air intake duct according to said one aspect of the invention.

The invention will now be described by way of example and with reference to the accompanying drawings, of which :- Fig. 1 is a side elevation of an engine compartment of a motor vehicle showing an internal combustion engine, and an air intake duct according to the invention; Fig. 2 is a view on arrow A of Fig. 1 showing the duct and a radiator;

Fig. 3 is a plan view on arrow B of the engine and air intake duct shown in Fig. 1 ; Fig. 4 is a cross-section through part of the air intake duct shown in Figs. l to 3 showing a main inlet valve having a valve member in a first, normal, position ; Fig. 5 is a view similar to Fig. 4 showing the main inlet valve member in a second, closed, position ; Fig. 6 is a view on arrow C in Fig. 4 ; and Fig. 7 is a cross-section through part of the air intake duct shown in Figs. l to 3 showing an auxiliary inlet valve.

Referring to Figs. l to 7, a motor vehicle 11 includes an engine compartment 12 which houses an internal combustion engine 13 having an intake manifold 14 supplied with air through an air filter assembly 15 which is part of an air intake duct 16. At the upstream end of the duct 16 there is a main inlet for the entry of air into the duct, the main inlet comprising two flow sensitive main inlet valves 17 and 18. Each inlet valve 17, 18 is at the upstream end of a respective generally rectangular section branch inlet duct 21, 22, the branch inlet ducts each extending over a radiator 23. The inlet duct 16 has an outlet at a flexible connector pipe 24 where it joins the inlet manifold 14. The inlet duct 16 also includes an auxiliary inlet 25 downstream of the main inlet valves 17, 18.

As shown in more detail in Figs. 4 to 6, each main inlet valve 17, 18 comprises a main inlet valve member in the form of a pivoted flap 31 which is connected by an integral hinge 32 to an inlet housing 33 of a resilient plastics material, each housing 33 forming part of the respective branch inlet duct 21, 22. Figs. 4 and 6 show the flap 31 in a lower, open, position where it rests on ledges 34, 35 at the lower end of housing sidewalls 36, 37. The housing 33 also includes an upper generally horizontal wall portion 38, and a leading wall portion 39 which, together with an intermediate wall portion 41, form part of the inlet duct 16. There is a

curved transition portion 42 between the upper wall portion 38 and the leading wall portion 39. The sidewalls 36, 37 also include an inclined overhanging step 43, 44 respectively which provide an abutment for the flap 31 when in a closed position as shown in Fig. 5.

As installed in the vehicle 11, each main inlet valve 17,18 has the leading wall portion 39 facing the normal direction of travel which is the same as the direction of arrow"C"in Fig. 4. An inlet opening is thus defined by the intermediate wall portion 41, a trailing edge 45,46 of the respective sidewall 36, 37 and a trailing edge 47 of the flap 31, this inlet opening facing away from the normal direction of travel of the vehicle.

The auxiliary inlet 25 is controlled by an auxiliary inlet valve 51 which comprises a flap 52 pivoted at a pivot 53 and spring loaded into a closed position by a tension spring 54 acting between a housing portion 55 of the inlet duct 16 and an arm 56 connected to the pivot 53. The flap 52 rests against a step 57 in the housing portion 55.

In normal use of the vehicle, the auxiliary air inlet 25 is closed by the auxiliary inlet valve 51 and the flap 31 of each main inlet valve 17,18 is in the open position as shown Figs. 4 and 6. The engine 13 can thus draw in air from the inlet manifold 14 through the duct 16 and the main inlet valves 17 and 18. If the vehicle encounters a flood or a ford then, depending upon the speed of the vehicle, a bow-wave will build up in front of the vehicle and water is liable to enter the inlet valves 17 and 18. However, the lower face of each of the flaps 31 each act as an impact surface which is acted on by the water attempting to enter the inlet valves 17,18 and each flap rapidly pivots into the closed position as shown in Fig. 5 to prevent water entering the duct 16.

With the engine still running and the inlet valves 17, 18 closed, there is a reduced pressure in the duct 16 which causes the flap 52 of the auxiliary inlet valve 51 to move against the bias of the spring 54 to allow air to enter the inlet duct 16 through the auxiliary inlet valve 51 and allow the engine 13 to continue running. Upon leaving the flood or ford when there is no water impinging upon the flap 31, the flap can drop back under gravity to rest on the ledges 34 and 35.

The increased pressure in the inlet duct 16 allows the auxiliary inlet valve 51 to close and the inlet duct then functions as normal.

It will be appreciated that because the main inlet valve 17 and 18 are positioned at the upstream end of the duct 16 there is no opportunity for water to enter the duct 16 and thus there is no momentum of ingested water to dissipate.

If required, an auxiliary air inlet duct can be connected to the auxiliary air inlet 25 to draw air from an appropriately dry area of the engine compartment 12.

Similarly, and if necessary, a small drain valve can be incorporated in a low position of the inlet duct 16 in the event of small quantities of water entering the duct and accumulating in there.

The main inlet valve flap 31 may be spring-biased into the open position if required, although the action of the integral hinge 32 will be to provide some degree of resilient bias. Similarly, the auxiliary inlet valve may incorporate a reed valve type of valve member where one end of a resilient flap is fixed (cantilevered) and the flap bends to allow the ingress of air.

When the main inlet valves 17 and 18 are in the open position as shown in Fig. 4, the main inlets face away from the normal direction of travel so that they are not subjected to the full momentum of water impinging upon the front of the vehicle. Because each flap 35 pivots about an edge at the integral hinge 32 which is leading relative to the direction of travel of the vehicle this allows the flap to act in a manner of a hydroplane so that it can start to close without water being ingested into the duct 16.

Although two main inlet valves 17 and 18 are shown, it will be appreciated that only one such valve may be used, depending upon the installation constraints of the particular vehicle.

Claims

CLAIMS 1. An air intake duct for an internal combustion engine in a motor vehicle, the duct including a main inlet for the entry of air into the duct, an outlet for the transfer of air from the duct to the engine and an auxiliary inlet for the entry of air into the duct downstream of the main inlet, the main inlet being at the upstream end of the duct and comprising a flow sensitive main inlet valve which in use is normally open to allow the passage of air into the duct but closes to prevent the entry of water into the duct and the auxiliary inlet being controlled by an auxiliary inlet valve which is normally closed but is operational to open when the main inlet is closed by the main inlet valve.
2. A duct according to claim 1 wherein the main inlet valve comprises a main inlet valve member having an impact surface, the main valve member being normally biased into an open position and being closed by the momentum of water approaching the main inlet acting on the impact surface.
3. A duct according to claim 2 wherein the main inlet valve member is biased by gravity into the open position.
4. A duct according to claim 2 or claim 3 wherein the main inlet valve member comprises a pivoted flap.
5. A duct according to claim 4 wherein the pivoted flap is hinged about one edge thereof.
6. A duct according to any of claims 2 to 5 wherein the main inlet valve member is spring biased into the open position.
7. A duct according to any preceding claim when installed in a motor vehicle and wherein the main inlet faces away from the normal direction of travel.
8. A duct according to claim 7 when dependent upon claim 5 wherein the said one edge of the pivoted flap is leading relative to the main inlet in the normal direction of travel.
9. A duct according to any preceding claim wherein the auxiliary inlet valve comprises a spring loaded auxiliary valve member which is spring loaded into the closed position.
10. A motor vehicle having an internal combustion engine and an air intake duct according to any preceding claim.
11. An air intake duct for an internal combustion engine in a motor vehicle, the duct being substantially as described herein with reference to the accompanying drawings.
12. A motor vehicle having an internal combustion engine and an air intake duct substantially as described herein with reference to the accompanying drawings.