EP0252178B1 - Shell for the drive engine in a motor vehicle - Google Patents

Abstract

1. A device for sound damping of an internal combustion engine in a motor vehicle, in particular a commercial vehicle, by means of a casing (1) enclosing the engine and being spaced at a slight distance away therefrom, the casing being self-supporting, of multi-part construction and comprising a basic casing member (2) forming an assembly unit together with the basic engine (3), and an upper cover (4) and oil sump case (5) detachably connected with the basic casing member (2), the basic casing member (2) having openings for connecting the engine (3) with its subsequently assemblage or exchangeable auxiliary units, characterised in - that a plurality of auxiliary units from the following group of auxiliary units - air compressor, lighting mechanism, hydraulic motor as auxiliary steering means, exhaust gas turbocharger, change-speed gear, V-belt and V-belt pulley of the water pump, lighting mechanism and ventilator, torsional damper, tensioning pulleys, water thermostat, water pump, viscous coupling for the ventilator, water hoses, hose connections, fuel feed pump, fuel filter - have at least partially, or at certain regions thereof, connecting-casings connected either directly with the basic engine (3), with the auxiliary units, or with the basic casing member (2), and - that paths in the interior of the casing (1) are provided with sound-absorbing material and are impinged by an amount of scavenging air which is so small that it effectively prevents a danger of explosions resulting from the accumulation of gases.

Description

The invention relates to a device for soundproofing a drive motor in a motor vehicle, in particular a commercial vehicle, by means of a capsule enclosing it at a short distance.

In order to reduce the noise pollution from vehicles driven by internal combustion engines to the outside, it has gone over to encapsulating the internal combustion engines. Such a device for sound-absorbing installation of an internal combustion engine is disclosed in the automotive engineering magazine ATZ, 1972, page 267.

In the embodiment of a sound-absorbing casing of an internal combustion engine disclosed in this publication, however, the cooling flow of a cooling fan is to be guided through the capsule. Such a passage of cooling air through a closed muffler capsule has the purpose of cooling the additional motor assemblies arranged within the muffler capsule in order to keep the temperature increase caused by the capsule or the engine's own heat development that cannot be dissipated within reasonable limits. A disadvantage of carrying the cooling air of a cooling fan through the capsule is that the cooling air inlet and outlet openings have to be made relatively large, in particular in the case of larger motors, and are therefore very difficult to protect against the escape of sound from the capsule.

A very significant disadvantage of the capsule described in the publication is that the auxiliary units are difficult to access for maintenance and repair purposes, even when closable openings are provided.

A device for sound damping of motors described at the outset is also known from DT-PS 306 982. However, this document does not deal with the problem of heat balance in the case of encapsulated motors and also gives no indication of how auxiliary units of the encapsulated motors can be protected against overheating.

A device for soundproofing an internal combustion engine in a motor vehicle by means of a capsule enclosing it at a short distance according to US Pat. No. 4,137,888 is known. The capsule is self-supporting and multi-part and consists of a capsule body, an upper cover and an oil pan cladding. With the exception of the injection pump, all auxiliary units are outside the casing.

The invention has for its object to provide a generic sound damping device that has a high degree of damping, which is designed to save space and weight, good accessibility to the drive motor and the associated units for maintenance and repair work and at the same time allows operating temperatures of the drive motor and to keep the other drive and auxiliary units low despite the soundproofing.

This is achieved according to the invention in that several auxiliary units from the group of the following auxiliary units - air compressor, alternator, hydraulic motor for steering aid, exhaust gas turbocharger, manual transmission, V-belts and V-belt pulleys from water pump, alternator and fan, torsion damper, tensioning rollers, water thermostat, water pump, viscous coupling for Fans, water hoses, hose connections, fuel feed pump, fuel filter - at least partially or partially have connection capsules, which are either connected directly to the basic motor (3), to the auxiliary units or to the basic capsule body (2) and that the interior of the capsule (1) is sound-absorbing Routes containing material are subjected to such a small amount of purge air, which just effectively prevents an explosion hazard due to the accumulation of gases. Since the capsule is arranged relatively close to the motor contour due to the exclusion of the auxiliary units, the sound damping begins immediately where the sound is generated, so that only a small area is illuminated by the main noise source. The exclusion of the auxiliary units has the further considerable advantage that only a small amount of air is used, which is not defined as cooling air but as purge air. In this way, a correspondingly large cooling fan is not required, since the small amount of purge air is only used for this, e.g. to effectively counter an explosion hazard due to the accumulation of gases. An essential advantage of the device according to the invention is that it is easy to maintain, repair and install; the capsule division optimally takes into account the band production by integrating the cubic, self-supporting capsule base body as an assembly part in the band production. The intervention options remain almost the same as for the unenclosed motor. By removing the upper cover, the following can be replaced: valve cover, cylinder heads, injector holder, screw connections of the injection lines, exhaust manifold and all corresponding seals. If the oil pan cover is also removed, the following can also be replaced: oil pan, pistons, connecting rods, cylinder liners, connecting rod bearings, crankshaft bearings and all corresponding seals and the like. The capsule body belongs to the engine and only needs if the crankcase is defective, e.g. due to frost damage. The capsule is a self-supporting structure provided with openings for the auxiliary units and should therefore not be understood as a series of facing shells. Since the soundproofing of an internal combustion engine is a very complex process, the measures described above must be supplemented by further, mainly additional encapsulations and primary soundproofing.

According to a supplementary feature of the invention, the effect of the purge air can be enhanced by air movement inside the capsule as a result of thermal effects and by the air flowing out of the radiator fan. Sol The capsule is then ventilated with a small amount of purge air to avoid the accumulation of flammable gases. Cooling air is not required because the heat-generating accessories are outside the capsule and the engine itself is water-cooled.

In a further embodiment of the invention, a partitioned space is provided around the exhaust manifold with corresponding supply and exhaust air openings, the partitioned space being provided by an additional capsule which is integral with the capsule base body and half with the upper cover, and with an additional capsule encompassing the exhaust manifold inlet Partition is formed. In this way, the air heated at the exhaust manifold is directed upwards, so that cold air (approx. 330 K) can be drawn in from the capsule and the air movement inside the capsule is supported. A quasi "divided room" is formed around the exhaust manifold with corresponding supply and exhaust air openings. Cooling in the area mentioned also makes sense because partial overheating is avoided and the use of particularly expensive materials (seals and high-quality alloys for exhaust manifolds and screws) is eliminated. Coking of the engine oil on the inside of the valve covers and heating of the cylinder head are also avoided.

According to further features, these encompassing and shielding front shells are arranged on the oil filter head and on the charging group of the exhaust gas turbine. In this way, the above-described auxiliary units, whose airborne sound radiation is measurably involved in the overall noise level, are shielded by absorbing front shells. The storage of the facing shells is decoupled from structure-borne noise on the internal combustion engine or on the auxiliary unit itself. The absorbing facing shells do not need to lie close to the capsule, but can be arranged at a distance from the capsule and the aggregate, so that assembly and maintenance are not impaired.

According to a further advantageous feature of the invention, additional damping against the noise resulting from axially similar vibrations is attached to a torsion damper consisting of a primary part and a secondary part having a rubber part, with shells being provided on both sides of the end faces of the torsion damper, one of which directly and the other via Connection plates, which are arranged within the V-belt guide, are connected to the outer wall of the capsule base body. Some rotating parts that come out of the capsule cannot be uncoupled sufficiently from the structure-borne noise of the engine due to their function, including the torsion damper in the front end of the crankshaft. This carries out torsional and axial vibrations. The torsional vibrations are eliminated by the rubber layer arranged between the primary and secondary part. Since the primary part is firmly screwed onto the crankshaft, damping by means of primary measures is not possible, so that the facing shells according to the invention are used. These can also be attached to the end faces of the torsion damper in a rotating manner.

It is also advantageous to use the various V-belt pulleys, e.g. B. for water pump and alternator to decouple structure-borne noise, the V-belt pulleys consist of primary and secondary parts, which are connected on the end face via several elastomer rings or the like and have a small annular space filled with viscose liquid on the inside. Pressed V-belt pulleys made of sheet metal, as are often used in diesel engines, are unsuitable for engines with capsules. V-belt pulleys must either have much more mass or, as the invention shows, there must be structure-borne noise decoupling. Additional damping is achieved by introducing viscose liquid between the hub parts.

According to a further feature of the invention, the vibrating metals connecting the capsule base body to the base motor are arranged on the outside of the capsule base body. In this way, they are visible, measurable and interchangeable without having to disassemble the capsule. They are also advantageously not influenced by the temperature prevailing in the capsule, which increases their resistance to aging.

According to other features of the invention, the exhaust pipe is structure-borne soundproofed, an outer pipe being arranged at a distance from the inner exhaust pipe and the space being made with an elastic fabric, e.g. B. asbestos substitute or filled with air, or it is the exhaust pipe in a certain, depending on the radiated frequency spectrum surrounded by a pipe silencer. There are strong pulsations in the suction line, which cause vibrations and harmonics. The acoustic weak points here are the inner compensators, as well as reinforced hoses, even in heavy versions.

In a particularly advantageous embodiment of the invention, the cavity between the motor and the capsule is filled with absorption material. The space between the capsule and the motor describes a diffuse reverberation space. Absorption material is installed to reduce the reverberation effect and thus increase the capsule effect. The points of absorption are not so significant. The percentage of the absorption area in the total area is more important. Damping pads are applied to strongly vibrating capsule surfaces beforehand.

Further features and advantages of the invention can be found in the claims, the description and the drawings.

The invention is illustrated in a large number of exemplary embodiments.

• Fig. 1 eine Motorkapsel in der Seitenansicht,
• Fig. 2 eine Motorkapsel in der Vorderansicht,
• Fig. 3 die Lagerung der Motorgrundkapsel,
• Fig. 4 die Einzelheit Kapselung des Abgaskrümmers,
• Fig. 5 die Einzelheit Kapselung des Ölfilters,
• Fig. 6 die Einzelheit Kapselung der Ladegruppe,
• Fig. 7 die Einzelheit Abschirmung des Torsionsdämpfers,
• Fig. 8 die Einzelheit Abschirmung des Torsionsdämpfers,
• Fig. 9 die Einzelheit körperschallentkoppelte Keilriemenscheibe,
• Fig. 10 die Einzelheit körperschallisoliertes Abgasrohr,
• Fig. 11 die Einzelheit körperschallisoliertes Abgasrohr,
• Fig. 12 die Einzelheit Ansaugleitung mit Oberflächenschalldämpfer

Show it:

• 1 is a side view of an engine capsule,
• 2 is a motor capsule in the front view,
• 3 the storage of the motor base capsule,
• 4 shows the detail encapsulation of the exhaust manifold,
• 5 shows the detail encapsulation of the oil filter,
• 6 shows the detail encapsulation of the loading group,
• 7 shows the detail shielding of the torsion damper,
• 8 the detail shielding of the torsion damper,
• 9 the detail of structure-borne noise-decoupled V-belt pulley,
• 10 shows the detail of structure-insulated exhaust pipe,
• 11 shows the detail of structure-insulated exhaust pipe,
• Fig. 12 shows the detail of intake pipe with surface silencer

1 and 2 show an internal combustion engine (3) with a complete capsule (1), which consists of a capsule base body (2), an upper cover (4) and an oil pan lining (5). The individual capsule components are preferably connected to one another via commercially available quick fasteners. A serious feature of this capsule arrangement is that all of the auxiliary units that are not absolutely necessary for a test run are located outside the capsule and additional measures have been taken to reduce their noise component in the overall noise level. In this way there is no cooling of the heat-radiating auxiliary units which, if they were arranged in the capsule, would require a cooling air flow and thus an additional large-volume cooler. However, it is sufficient to branch off a very small amount of purge air from the radiator fan so that no flammable gases can form inside the capsule.

Fig. 3 shows the connection of the capsule body (2) to the motor housing (8), namely by means of vibrating metal elements (6, 7), which are attached to the outside of the capsule, so that each one can be replaced without disassembling the capsule itself.

Fig. 4 shows the encapsulation of the exhaust manifold (9) by means of a capsule part (11), which is assigned in one piece to the capsule body (2) and the other half in one piece to the upper cover (4). By arranging a partition (12) on the engine-facing part of the exhaust manifold, enclosing the same, a partitioned space (10) is created, whereby the air heated at the exhaust manifold is directed upwards and cold air (approx. 330 K) is drawn in from the lower capsule area . The cutting disc (12) consists of a sheet with an insulating layer (14) and a steel sheet (13) attached to it, on which a further steel sheet (15) is arranged at a distance.

Fig. 5 shows an oil filter head (16) with a spaced absorbent facing (17). This arrangement allows easy access to the oil filter at any time to perform maintenance or cleaning tasks on it.

Fig. 6 shows the charging group (18), (gas turbine + compressor) with a noise-absorbing front shell (19) arranged at a distance from it.

Fig. 7 shows a torsion damper (23) and Fig. 8 shows the arrangement of this torsion damper in a front view. The primary part (20) of the torsion damper (23) attached to the crankshaft is connected via a rubber part (22) to a secondary part (21) containing the V-belt grooves. Front shells (24, 25) are arranged on the front side of the torsion damper (23), the front shell (24) being attached directly and the front shell (25) via connecting plates (26) on the outer wall of the capsule base body. The size of the facing shells corresponds to the diameter of the torsion damper (23). The connecting plates (26) lie within the V-belt guide (27) of the torsion damper (23), alternator V-belt pulley (28) and water pump V-belt pulley (29). The facing shells (24, 25) can also be firmly connected to the torsion damper (23). The V-belt pulleys (28, 29) consist of a primary part (30) and a secondary part (31). These are connected to one another at the end face via elastomer rings (32, 33). On the inside there is an annular space (33) between the parts (30) and (31), which is filled with viscose material.

Figures 10 and 11 show structure-borne noise-insulated exhaust pipes (34). The exhaust pipes between the manifold and the muffler in conventional design already emit considerable airborne noise caused by structure-borne noise. To reduce this, an outer pipe (35) is arranged at a distance from the exhaust pipe (34), the intermediate space (36) being filled with an elastic intermediate layer (36) (e.g. asbestos substitute) or air. According to a variant according to FIG. 11, the exhaust pipe (34) is surrounded by a silencer (37), which consists of a perforated plate (39), absorption material (40) and an outer pipe (41) arranged at a distance from it.

Fig. 12 shows an intake pipe (42) with surface silencer (46). The suction line (42) is composed of a partial section (43) and a partial section (44) which are connected by an inner compensator (45). The internal compensator is completely sufficient for an unenclosed motor, but not for an encapsulated one. The external expansion joints (47, 48), which are arranged at the end and are connected to the silencer (46), are used here. The surface silencer (46) with external expansion joints (47, 48) is preferably used if a short overall length is required and / or very high pulsations and vibrations are present.

Openings, here not provided with reference numerals that are important for maintenance work, such as. B. oil filler neck, nozzle for oil level control and oil drain are led out of the capsule.

The space between capsule (1) and motor (3) describes a diffuse reverberation space; To reduce the reverberation effect and thus increase the capsule effect, absorption material is installed. The locations of the absorption are not so significant; what is more important is the percentage of the absorption area in the total area, the thickness of the absorption material being limited by the space between the capsule and the motor.

In order to have the possibility to change the geometrical position of chap To be able to test sel, there are holes at certain points in the capsule which can be used to measure the reference points on the motor. The reference points on the engine are specially machined surfaces.

Claims (20)

1. A device for sound damping of an internal combustion engine in a motor vehicle, in particular a commercial vehicle, by means of a casing (1) enclosing the engine and being spaced at a slight distance away therefrom, the casing being self-supporting, of multi-part construction and comprising a basic casing member (2) forming an assembly unit together with the basic engine (3), and an upper cover (4) and oil sump case (5) detachably connected with the basic casing member (2), the basic casing member (2) having openings for connecting the engine (3) with its subsequently assemblable or exchangeable auxiliary units, characterised in

- that a plurality of auxiliary units from the following group of auxiliary units - air compressor, lighting mechanism, hydraulic motor as auxiliary steering means, exhaust gas turbocharger, change-speed gear, V-belt and V-belt pulley of the water pump, lighting mechanism and ventilator, torsional damper, tensioning pulleys, water thermostat, water pump, viscous coupling for the ventilator, water hoses, hose connections, fuel feed pump, fuel filter - have at least partially, or at certain regions thereof, connecting-casings connected either directly with the basic engine (3), with the auxiliary units, or with the basic casing member (2), and

- that paths in the interior of the casing (1) are provided with sound-absorbing material and are impinged by an amount of scavenging air which is so small that it effectively prevents a danger of explosions resulting from the accumulation of gases.

2. A device according to claim 1, characterised in that the action of the scavenging air can be intensified by air movement in the interior of the casing, re- suiting from warm air currents, and by the outflowing air from the radiator ventilator.

3. A device according to claim 1, characterised in that the basic casing member (2) is secured by means of metal rocker elements (6, 7) on at least three points in the upper and on at least three points in the lower region of the motor housing (8).

4. A device according to claims 1 to 3, characterised in that a compartmented space (10), with corresponding air supply- and air exhaust -openings, is provided around the exhaust manifold (9).

5. A device according to claim 4, characterised in that the compartmented space (10) is formed by an additional casing (11), one half of which is integrally associated with -the upper cover (4) and the other half of which is integrally associated with the basic casing member (2), and by a partition wall (12) which engages around the exhaust manifold inlet.

6. A device according to claims 4 and 5, characterised in that the partition wall (12) comprises a simple steel plate (13), a metal plate with an insulating layer (14), and two steel plates (13, 15) which are arranged spaced at a distance from one another.

7. A device according to any one, or more, of the claims 1 to 3, characterised in that on the oil filter head (16) there is arranged a sound-absorbing shell-shaped attachment (17) which engages around the oil filter head in a half-shell shape.

8. A device according to any one or more of the claims 1 to 3, characterised in that on the charging group (18) (extractor turbine with compressor) there is arranged a shell-shaped attachment (19) which screens the said group.

9. A device according to any one or more of the claims 1 to 3, characterised in that on a torsional damper (23) which comprises a primary part (20) and a secondary part (21) having a rubber part (22), there is arranged an accessory damping means for damping the noise resulting from vibrations similar to axial vibrations.

10. A device according to claim 9, characterised in that on both sides of the front surfaces of the to- sional damper (23), shell-shaped attachments (24, 25) are provided, one of which (24) is connected directly with the outer wall of the basic casing member (2), and the other (25) of which is connected with the outer wall by means of metal connecting plates (26), [sic]^* which are arranged within the V-belt guide means (27).

11. A device according to any one or more of the claims 1 to 3, characterised in that the different V-belt pulleys (28, 29) are decoupled from structure-borne sound.

12. A device according to claim 11, characterised in that the V-belt pulleys (28, 29) comprise primary (30) and secondary (31) parts connected together at the front side by means of a plurality of elastomer rings or the like, and which have on the inside a small annular space (33) filled with viscous fluid.

13. A device according to any one or more of the claims 1 to 3, characterised in that the metal rocker elements (6, 7) which connect the basic casing member (2) with the basic engine (3) are arranged on the outside of the basic casing member (2).

14. A device according to any one or more of the claims 1 to 3, characterised in that the engine suspension means are arranged outside the casing (1), the support arms on the engine side being provided at places of least structure-borne sound intensity.

15. A device according to any one or more of the claims 1 to 3, characterised in that the exhaust pipe (34) is constructed so as to be insulated from structure-borne sound.

16. A device according to claim 15, characterised in that an external pipe (35) is arranged spaced at a distance in relation to the inner exhaust pipe (34), and the space (36) therebetween is filled with an elastic woven fabric, e.g. asbestos substitute, or with air.

17. A device according to claim 15, characterised in that the exhaust pipe (34) is surrounded by the tubular sound damping device (37), which is spaced away at a particular distance (38) which is dependent upon the radiated frequency spectrum.

18. A device according to any one or more of the claims 1 to 3, characterised in that the induction manifold (42) comprises two tubular sections (43, 44) which are connected by means of an inner compensator (45) and which are encased in a surface sound-damping means (46) and which have external compensators (47, 48) on their ends.

19. A device according to any one or more of the claims 1 to 3, characterised in that the casing (1) has openings for oil-filler pipe-sections, and also for pipe-sections for checking the oil and for the oil drainage.

20. A device according to any one or more of the claims 1 to 19, characterised in that the hollow space between engine (3) and casing (1) is filled with absorption material and damping material, both materials being spaced by a further distance in relation to the surface of the engine.

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