GB2045696A

GB2045696A - Motor vehicle with a sound- suppressing compartment for the engine unit

Info

Publication number: GB2045696A
Application number: GB8003816A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-02-07
Filing date: 1980-02-05
Publication date: 1980-11-05
Also published as: GB2045696B; FR2448448B2; IT8019710A0; JPS5926017U; FR2448448A2; AT369700B; SE8000815L; JPS55106821A; IT1141162B; ATA92679A; DE3001466A1

Abstract

The engine is connected to the sump (6) by means of a sound insulating element (7) and mounted so that at least the cylinder block (11) is in a noise suppressing compartment which in addition to the vehicle body parts is defined by walls (12, 13, (14)) so that the compartment surrounds the cylinder block (11) closely. The compartment is completed on the upper side by the bonnet (20) and on the lower side by a flexible membrane (15). By arranging for the carburettor (21) to be mounted outside the compartment with the induction manifold (23) inside, and for the exhaust manifold (27) to have its own sound suppressing shroud (31) on the outside of the compartment, it is possible to bring the compartment walls nearer to the cylinder block (11) without affecting the accessibility of parts requiring regular maintenance. This arrangement gives rise to better sound suppression and engine cooling at low cost. The compartment itself may be cooled by a fan (33). <IMAGE>

Description

SPECIFICATION Motor vehicle with a sound-suppressing compartment for the engine unit This invention relates to a motor vehicle comprising, an engine having an oil sump which is secured to an engine power unit in a bodysound-insulated manner, a fan cooled radiator, a frame-mounted elastic membrane provided between the oil sump and the vehicle body components so that said membrane completely encircles the oil sump at the level of its upper edge and provides acoustic separation between the spaces respectively situated above and below said upper edge, the upper space being converted by the membrane into a sound suppressing compartment which is closed relative to the vehicle interior by appropriate wall parts and sealing sections provided on the vehicle body, and the outflow of heated cooling air from the radiator is conducted wholly outside of the compartment.

A motor vehicle of the kind hereinabove defined is known from British Patent Specification No. 1 560335. Such vehicles will hereinafter be referred to as vehicles of the kind defined.

By this arrangement known from the prior proposal a very good noise reduction with only an insignificant increase in weight of the vehicle can be achieved. Because of the relatively great distances between the sound emitting engine surfaces and those vehicle body components used to form the sound-suppressing compartment it is advisable to provide at least some of the compartment walls with sound absorbing material. Compared with known fully encased engines there are indeed better conditions present for by-passing the hot air from the radiator, however, a relatively great distance between the radiator and the front wall of the compartment is necessary, which is disadvantageous for the mounting of the engine.

It is an object of this invention to develop a motor vehicle of the kind known from the above-numbered prior proposal to obtain in a simple and weight-saving manner a further improvement in the sound reduction and, simultaneously, better mounting conditions for the engine and more favourable conditions for by-passing air heated by the radiator of the vehicle. This should also be possible in motor vehicles having an engine-gearbox-unit arranged transversely to the driving direction.

The present invention consists in a motor vehicle comprising, an engine having an oil sump which is secured to an engine power unit in a body-sound-insulated manner, a fan cooled radiator, a frame-mounted elastic membrane provided between the oil sump and the vehicle body components so that said membrane completely encircles the oil sump at the level of its upper edge and provides an acoustic separation between the spaces respectively situated above and below said upper edge, the upper space being converted by the membrane into a sound suppressing compartment which is closed relative to the vehicle interior by appropriate wall parts and sealing sections provided on the vehicle body and the outflow of heated cooling air from the radiator is conducted wholly outside of the compartment, characterised in that, at least one additional wall is disposed between the engine power unit and the vehicle body components which is spaced from the engine unit by only the minimum distance required for accessibility to the parts in need of maintenance.

With this arrangement the distance of at least some of the additionally built in walls from the engine unit can be kept smaller with the result that the sound insulation of the compartment is essentially improved. Simultaneously, in vehicles having an engine-gearbox-unit disposed transversely to the driving direction, very much more free space is provided behind the correspondingly arranged radiator, whereby the heated cooling air can by-pass the engine without restraint. Corresponding to a drop in back pressure so obtained it is possible to use a fan with less power consumption, which also produces less noise.

According to a further embodiment of this invention, wherein the vehicle engine is a carburettor engine having an inlet manifold of the single-tube type which comprises a single feed tube positioned in the region of the carburettor, the carburettor and at least a part of the inlet manifold connected to the carburettor are arranged outside the compartment and are connected to the part of the inlet manifold arranged inside the compartment by means of a body-sound-insulating member, and the feed tube of the inlet manifold extends through one of the compartment walls without contact therewith and thus forms a gap with the wall which is sealed with an elastic sealing element. Thereby, it is possible to bring the side wall on the intake-side of the engine nearer to the engine unit, whereby the above-mentioned advantages are emphasised.

Moreover, by the arrangement of the carburettor and a part of the inlet manifold outside the sound insulating compartment an undesirable heating up of the carburettor and, therefore, danger of fire is largely prevented. By means of body-sound insulating connection of that part of the inlet manifold arranged outside the compartment to the part arranged inside the compartment, the emission of sound via the carburettor is avoided, so that the sound insulation of the compartment is not affected.

Especially in vehicles having an engine with a so-called spider inlet manifold or, an air intake duct with intake stubs connected to it, it can be advantageous if, according to a further feature of this invention the inlet mani fold is arranged wholly outside the sound suppressing compartment and has stub pipes extending through one of the compartment walls without contact therewith and which pipes are sealed against the wall by means of elastic sealing elements and connected to the engine unit by means of body-sound-insulated intermediate members. Thereby it is possible to bring the air intake-side wall of the compartment still nearer to the engine unit and, consequentially to reduce the volume of the compartment further.

According to another feature of the present invention it can be provided for, that the exhaust manifold of the engine is arranged outside the sound suppressing compartment and, together with a part of an exhaust pipe connected to the exhaust manifold, enclosed by a separate exhaust covering. The exhaust manifold comprises branch pipes which extend through the compartment wall without contact therewith, and the exhaust pipe itself penetrates the exhaust covering through an absorption silencer. Consequently, it is possible to bring the exhaust outlet-side wall near to the engine unit, too, and an undersirable heating of the compartment is prevented. Simultaneously, the sound emission from the exhaust is effectively reduced by the provision of a separate exhaust covering and by the provision of a sound absorption silencer where the exhaust pipe extends through the covering.For better body-sound insulation the branch pipes of the manifold can be provided with body-sound-insulating intermediate members.

According to a still further embodiment of this invention the sound suppressing compartment is provided with a ventilation fan and at least one inlet and one outlet duct for the ventilation of the compartment with air, and the inlet and outlet ducts are provided with sound-absorbing silencers. This is favourable if suitable heat shielding of the exhaust manifold against the inside of the compartment is not obtained by the above-mentioned exhaust covering.

Especially in a vehicle having a carburettor arranged inside the sound-suppressing compartment the danger of fire can largely be avoided by the pressure cooling of the compartment. By the arrangement of sound-absorbing silencers at the inlet duct as well as at the outlet duct of the compartment it is assured that the level of sound-suppression achieved by the design is maintained.

According to a further development of this invention a dividing wall is disposed in the sound suppressing compartment so as to separate a part of the compartment containing hot exhaust system components from the other part thereof, the dividing wall being arranged to divide air ventilating the compartment into one stream which flows over the hot exhaust system components and into another stream which flows over other parts of the engine, and two outlet ducts are provided in the compartment walls for venting said streams. This arrangement of the cooling air path gives the advantage of a well defined cooling system which takes the different requirements for cooling the exhaust system and the less hot surfaces of the engine into consideration, whereby the power consumption of the fan for ventilating the inside of the compartment can be reduced.

According to a preferred embodiment of the invention the sound-suppressing compartment is closed on the upper side thereof by the vehicle bonnet, whereby an optimum accessibility to the engine and considerable advantages concerning the costs of manufacture and assembly as well as the weight of the vehicle are achieved.

Finally, in accordance with this invention and for an enhanced effect thereof, the vehicle bonnet is provided with additional sound insulation in the region of the compartment.

Consequently, yet further improved soundsuppression can be obtained without affecting the advantages already obtained in any way, as because of the relatively small areas of the bonnet which must be provided with sound insulating material, only an insignificant increase in weight results.

An embodiment of the invention will hereinafter be more specifically described by way of example with reference to and illustrated diagramatically in the accompanying drawings wherein: Figure 1 is a sectional view aong line 1-l in Fig. 2 of the front part of a motor vehicle incorporating the details of the invention, and Figure 2 is a view along arrow II in Fig. 1 of the open engine compartment.

A motor vehicle 1 shows an engine 2, mounted transversely to the driving direction, which has a variable speed gear box and differential unit 3 rigidly connected to same.

The housing for the gear box and a clutch has the reference 4. An oil sump 6 is fixed to an engine power unit 5 by means of a vibration insulating element 7. The power unit comprises those parts of the engine which produce power, such as the cylinder block, cylinder head, crankshaft and crankshaft main bearings and which are mainly responsible for producing vibrations and noise. The vibration insulating element 7 is rigidily connected to an upper and lower holding frame 8, 9, and the upper frame 8 is fixed to a flange 10 of the cylinder block 11 and the lower frame 9 is fixed to the oil sump 6.

The upper part of the engine unit including the cylinder block and cylinder head is enclosed on two sides and at the end near the clutch by walls 12, 13, 14 which are spaced from the surface of the engine unit only the minimum distance which does not hinder the accessibility to parts in need of maintenance, as, for example, the sparking plugs or the fuel injectors if used. A frame-type rubber membrane 1 5 is provided at and extends along the lower rims of the walls 12, 13, 14, and lies close to or in contact with the lower holding frame 9 of the vibration insulating element 7 or the upper rim of the oil sump 6 and, therefore, provides acoustic sealing of a space 1 6 above the membrane 1 5 from a space 1 7 below the membrane.A part 1 8 of the engine unit lying above the membrane 1 5 is encased for noise suppression. The sound-suppressing compartment, formed by the wall 1 2 on the air intake side of the engine, the wall 1 3 of the exhaust side, the lateral wall 14 at one end and a body component wall 1 9 comprising the wheel box of the vehicle, is closed on the upper side by the bonnet 20 of the vehicle. A soft sealing element 20', for example of foam rubber, is provided along the upper rims of the walls 12, 13, 14, which enables a substantially accoustically tight covering of the sound-suppressing compartment tobe made. Alternatively, such element 20' may be secured to the bonnet itself.

The motor vehicle in the depicted exemplary embodiment shows an engine provided with a carburettor 21 which is arranged together with an air filter 22 outside the soundsuppressing compartment 1 6. The inlet manifold 23 is of single-tube type and comprises a single feed tube positioned in the region of the carburettor and branch pipes which are arranged inside the compartment. The side wall 1 2 on the air intake side of the compartment has an opening 24, through which the feed tube part of the inlet manifold extends without contact. In the region of the opening 24, on the inside the compartment, the connection between the feed tube and the branched part of the inlet manifold 23 is established via a vibration insulating intermediate member 25.The opening 24 is acoustically sealed on the outside by an elastic sealing element 26, which on the one side is fixed to a flange on the side wall 1 2 and on the other side to the feed-tube part of the inlet manifold 23. However, it is possible for example, in engines having so-called spider inlet manifolds or in engines with fuel injection and having air intake ducts with intake stubs connected to them, that the inlet manifold is arranged completely outside the sound-suppressing compartment, and that separate body-sound insulating intermediate members 25 are provided for the connection of each stub pipe to each cylinder.The extension of such an inlet manifold through the compartment side wall on the intake side can be made via spaced adjacent openings which are sealed by separate sealing elements 26, or via a suitable slotted hole provided in the wall 1 2 and sealed by a single oval shaped element.

An exhaust manifold 27 having an exhaust pipe 28 connected thereto is mounted on the exhaust-side of the engine. Exhaust connecting branch pipe 29, which can be provided with vibration insulating intermediate members, extend through openings in the side wall 1 3 on the exhaust side of the compartment and form therewith slits 30. The exhaust manifold 27, arranged outside the soundsuppressing compartment, and a portion of the exhaust pipe 28 attached thereto are encased by a separate exhaust covering 31 fixed to the side wall 1 3. The exhaust pipe 28 where it emerges from the exhaust covering 31 is provided with an absorption silencer 32 surrounding the pipe 28.

A separate ventilation fan 33 is provided for the ventilation of the inside of the soundsuppressing cpmpartment which is driven by means of a V-belt 34 from the engine crankshaft or by an overhead camshaft or an electric motor. It is also possible to drive the fan 33 via a toothed belt provided for the camshaft drive (not shown). The cooling air for the inside of the sound-suppressing compartment is drawn in, as indicated by arrow 36, by the fan 33, via an air inlet 35 provided in the vehicle body wall 1 9 which is designed as an absorption silencer, and is blown over the surface of the engine unit. The output for the cooling air, as indicated by arrow 38, is through an outlet opening 37 provided in the lateral wall 14 at a position close to the side wall 1 2 and designed as an absorption silencer.Air also emerges from the slit 30 and the annular absorption silencer 32 as indicated by the arrows 39.

To improve the cooling of the inside of the sound-suppressing compartment a dividing wall 40 is attached to a valve cover plate 41 which, if the vehicle bonnet 20 is closed, functions to divide the incoming cooling air into two streams; one stream flows over the hot parts of the exhaust system and the other over other engine parts. For a better separation of both steams the dividing wall 40 is sealed against the vehicle bonnet 20 by means of an elastic sealing element 42. The cooling air stream which flows over the hot parts of the exhaust leaves the sound-suppressing compartment via the slit 30 in the wall 1 3 on the exhaust side of the compartment and through the absorption silencer 32, as indicated by arrows 39. The cooling air stream flowing over the cooler parts on the intake-side of the engine leaves the compartment via the opening 37.

The radiator 43 is arranged in the engine compartment laterally staggered with the engine unit and in front of the gear box and differential unit 3, whereby the cooling air conveyed by ram pressure or a fan 45 driven by an electric motor 44, respectively, can leave the engine compartment unimpededly after passing through the radiator 43. As the sound suppressing compartment according to the present invention has only absolutely nec essary dimensions, it is always possible, even when the engine is mounted transversely to the driving direction, to arrange the radiator 43 and the fan 45 in the engine compartment in such a way to allow the heated air to pass of unimpededly. Obviously, the invention is also practicable in vehicles with a rear engine and in vehicles with a conventionally frontmounted engine and gear box arranged on the rear axle of the vehicle.

Claims

1. A motor vehicle comprising, an engine having an oil sump which is secured to an engine power unit in a body-sound-insulated manner, a fan cooled radiator, a framemounted elastic membrane provided between the oil sump and the vehicle body components so that said membrane completely encircles the oil sump at the level of its upper edge and provides acoustic separation between the spaces respectively situated above and below said upper edge, the upper space being converted by the membrtane into a sound suppressing compartment which is closed relative to the vehicle interior by appropriate wall parts and sealing sections provided on the vehicle body, and the outflow of heated cooling air from the radiator is conducted wholly outside of the compartment, characterised in that, at least one additional wall is disposed between the engine power unit and the vehicle body components which is spaced from the engine unit by only the minimum distance required for accessibility to the parts in need of maintenance.

2. A motor vehicle according to Claim 1, wherein the vehicle engine is a carburettor engine having an inlet manifold of the singletube type which comprises a single feed tube positioned in the region of the carburettor, the carburettor and at least a part of the inlet manifold connected to the carburettor are arranged outside the compartment and are connected to the part of the inlet manifold arranged inside the compartment by means of a body-sound-insulating member.

3. A motor vehicle according to Claim 2, wherein the feed tube of the inlet manifold extends through one of the compartment walls without contact therewith and forms a gap with the wall which is sealed with an elastic sealing element.

4. A motor vehicle according to Claim 1, wherein the inlet manifold is arranged wholly outside the compartment and has suction branch pipes extending through one of the compartment walls without contact therewith.

5. A motor vehicle according to Claim 4, wherein the suction branch pipes are sealed against the compartment wall by means of elastic sealing elements and connected to the engine unit by means of body-sound-insulated intermediate members.

6. A motor vehicle according to any one of Claims 1 to 5, wherein the exhaust manifold of the engine is arranged outside the compartment and, together with a part of an exhaust pipe connected to the exhaust manifold, enclosed by a separate exhaust covering.

7. A motor vehicle as claimed in Claim 6, wherein the exhaust manifold comprises branch pipes which extend through the compartment wall without contact therewith, and the exhaust pipe itself penetrates the exhaust covering through an absorption silencer.

8. A motor vehicle according to Claim 7, wherein the branch pipes are provided with body-sound-insulating intermediate members.

9. A motor vehicle according to any of the Claims 1 to 8, wherein the compartment is provided with a ventilation fan and at least one inlet and one outlet duct for the ventilation of the compartment with air.

10. A motor vehicle according to Claim 9, wherein the ducts are provided with soundabsorbing silencers.

11. A motor vehicle according to Claim 9 or Claim 10, wherein a dividing wall is disposed in the compartment so as to separate a part of the compartment containing hot exhaust components from the other part thereof, the dividing wall being arranged to divide air ventilating the compartment into one stream flowing over the hot exhaust system components and into another stream flowing over other parts of the engine.

1 2. A motor vehicle according to Claim 11, wherein two outlet ducts are provided in the compartment walls for venting said streams.

1 3. A motor vehicle according to any of the Claims 1 to 11, wherein the sound suppressing compartment is closed on the upper side thereof by means of the vehicle bonnet.

14. A motor vehicle according to Claim 13, wherein the vehicle bonnet is provided with additional sound insulation in the region of the compartment.

1 5. A motor vehicle according to Claim 13, wherein the upper rims of the walls comprising the compartment are provided with a soft sealing element which makes contact with said bonnet when closed.

1 6. A motor vehicle substantially as hereinbefore described with reference to the accompanying drawings.