GB1604194A - Arrangement for reducing the noise radiated by internal combustion engines - Google Patents

Abstract

In internal combustion engines in which the crankshaft is fitted from below, vibrations occur at the bottom crank case flange, which are transmitted to the oil sump fixed to this and cause it to radiate sound, thereby increasing the overall noise of the engine. In order to reduce this radiated noise emission the bottom crank case flanges (2) are connected by transverse stiffening webs (6). The transverse webs (6) can be integrally connected to a frame (3) which is fixed to the crank case flanges (2) by means of bolts (4). The bolts (4) also hold a supporting flange (a), on which the oil sump (8) is supported by way of a rubber elastic element (7). <IMAGE>

Description

(54) ARRANGEMENT FOR REDUCING THE NOISE RADIATED BY INTERNAL COMBUSTION ENGINES (71) We, AKTIENGESELLSCHAFT ADOLPH SAURER, a joint stock company organised under the laws of Germany, of 9320 Arbon, Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to an arrangement for reducing noise radiated by internal combustion engines, more particularly vehicle engines which are provided with a crankcase, in which the crankshaft is fitted radially from below.

It is part of the state of the art in the case of reciprocating piston internal combustion engines with the crankshaft mounted in suspended fashion to arrange a spacer element below the lower bearing cover and to brace it with two ties. This effectively counteracts outward bending of the side portions of the machine frame. This measure of course also achieves increased rigidity in the complete arrangement, and thus reduces the radiation of noise (German laid-open specification 2 136 631).

On the other hand it is known in internal combustion engines to secure the crankcase as a separate non-loaded unit flexibly, for example by means of an elastic sealing element, to the rest of the engine structure, for example the supporting plate underside.

The crankcase is then subJected to vibrations to a lesser extent than normal (German laid-open specification 2 618 241).

These measures, however, cannot be regarded as sufficient in the "age of noise insulation", for which reason the present invention has set itself the object of further improving the situation as regards radiation of noise in internal combustion engines by taking combined measures.

In such engines, vibrations occur at the lower flange of the crankcase which are transmitted into the oil sump secured thereto and make the sump radiate noise, so that the total level of noise produced by the engine is increased. Insulation arrangements for insulating the oil sump from the crankcase flange are already known. The crankcase side walls also act as sound radiating devices and even their vibrations are not reduced by the measures taken to insulate the oil sump.

The invention aims at reducing vibrations of crankcase side walls and thus reducing the noises radiated by the engine.

Accordingly the present invention provides an arrangement for reducing noise emitted by an internal combustion engine of the type having a crankshaft fitted radially from below in a crankcase with an oil sump connected to the crankcase flanges, wherein the lower portions of the crankcase flanges are connected together by stiffening transverse webs, the transverse stiffening webs being either secured onto a frame or constructed as part of the frame with the crankcase flanges also connected to the frame and the oil sump connected to the frame by at least one elastomeric element.

Preferably, the transverse webs are secured to the frame by means of bolts.

The or each elastomeric element may be secured by vulcanisation.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a cross-section through the components in a first constructional arrangement of the invention Figure 2 shows a plan view of a transverse web; Figure 3 and Figure 4 show corresponding views of a second embodiment of the constructional arrangement.

In Figure 1, the lower portion of a crankcase side wall 1 is shown which ends in a external housing flange 2. Secured to the housing flange 2 by means of bolts 4 is a frame 3 which is provided with webs 6 between which intervening spaces 5 are provided (see Figure 2). These webs 6 through the agency of the housing flange 2 brace the opposite crankcase side walls 1 and thus stiffen this structure which is capable of producing vibrations. The oil sump, of which the upper portion of the side wall 8 is visible, is connectec by means of an elastomeric intermediate layer 7, with which it is united by vulcanisation or the use of an adhesive substance, and by way of a supporting flange 9 and bolts 4, with the frame 3 and the crankcase flange 2. The frame 3 comprises at its internal side a groove 12 into which there is interposed a packing or sealing element 10 for sealing the crankcase.

Figure 2 also shows two apertures 13 for bolts 4 in the web 6.

In the constructional arrangement shown in Figure 1 and 2, the frame 3 and the webs 6 are constructed as a one-piece casting. The spaces 5 form a passage for the crankshaft throws with the connecting rod heads and any counterweights which are provided.

In the constructional arrangement shown in Figure 3 and Figure 4, in which like parts have the same reference numerals as in the embodiment of Figure 1 and Figure 2, there is secured on the crankcase flange 2 a frame 15 by means of the bolts 4, and on to the internal side thereof is vulcanised an elastomeric intermediate layer 17. This intermediate layer 17 is used for supporting the side wall 8 of the oil sump, whose upper flange is also connected by vulcanisation to the elastomeric intermediate layer 17.

In this constructional form the webs 19 are each secured by means of two bolts 20 on the internal side of the frame 15. Here again sealing is effected by means of a sealing element 10 in the groove 12. The frame 15 is provided with suitable apertures 13.

WHAT WE CLAIM IS: 1. An arrangement for reducing noise, emitted by an internal combustion engine of the type having a crankshaft fitted radially from below in a crankcase with an oil sump connected to the crankcase flanges wherein the lower portions of the crankcase flanges are connected together by stiffening transverse webs, the transverse stiffening webs being secured onto a frame or constructed as part of the frame with the frame and the oil sump connected to the frame by at least one elastomeric element.

2. An arrangement as claimed in Claim 1, wherein the lower portions of the crankcase flanges are connected by the stiffening transverse webs which are secured on the frame or constructed as part of the frame.

3. An arrangement as claimed in Claim 1 or 2, wherein the transverse webs are secured to the frame by means of bolts.

4. An arrangement as claimed in any of Claims 1 to 3, wherein the or each elastomeric element is secured by vulcanisation.

5. An arrangement for reducing noise radiated by internal combustion engines, substantially as herein described, with reference to Figures 1 and 2, Figures 3 and 4 or Figures 5 and 6 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. a external housing flange 2. Secured to the housing flange 2 by means of bolts 4 is a frame 3 which is provided with webs 6 between which intervening spaces 5 are provided (see Figure 2). These webs 6 through the agency of the housing flange 2 brace the opposite crankcase side walls 1 and thus stiffen this structure which is capable of producing vibrations. The oil sump, of which the upper portion of the side wall 8 is visible, is connectec by means of an elastomeric intermediate layer 7, with which it is united by vulcanisation or the use of an adhesive substance, and by way of a supporting flange 9 and bolts 4, with the frame 3 and the crankcase flange 2. The frame 3 comprises at its internal side a groove 12 into which there is interposed a packing or sealing element 10 for sealing the crankcase. Figure 2 also shows two apertures 13 for bolts 4 in the web 6. In the constructional arrangement shown in Figure 1 and 2, the frame 3 and the webs 6 are constructed as a one-piece casting. The spaces 5 form a passage for the crankshaft throws with the connecting rod heads and any counterweights which are provided. In the constructional arrangement shown in Figure 3 and Figure 4, in which like parts have the same reference numerals as in the embodiment of Figure 1 and Figure 2, there is secured on the crankcase flange 2 a frame 15 by means of the bolts 4, and on to the internal side thereof is vulcanised an elastomeric intermediate layer 17. This intermediate layer 17 is used for supporting the side wall 8 of the oil sump, whose upper flange is also connected by vulcanisation to the elastomeric intermediate layer 17. In this constructional form the webs 19 are each secured by means of two bolts 20 on the internal side of the frame 15. Here again sealing is effected by means of a sealing element 10 in the groove 12. The frame 15 is provided with suitable apertures 13. WHAT WE CLAIM IS:

1. An arrangement for reducing noise, emitted by an internal combustion engine of the type having a crankshaft fitted radially from below in a crankcase with an oil sump connected to the crankcase flanges wherein the lower portions of the crankcase flanges are connected together by stiffening transverse webs, the transverse stiffening webs being secured onto a frame or constructed as part of the frame with the frame and the oil sump connected to the frame by at least one elastomeric element.

2. An arrangement as claimed in Claim 1, wherein the lower portions of the crankcase flanges are connected by the stiffening transverse webs which are secured on the frame or constructed as part of the frame.

3. An arrangement as claimed in Claim 1 or 2, wherein the transverse webs are secured to the frame by means of bolts.

4. An arrangement as claimed in any of Claims 1 to 3, wherein the or each elastomeric element is secured by vulcanisation.

5. An arrangement for reducing noise radiated by internal combustion engines, substantially as herein described, with reference to Figures 1 and 2, Figures 3 and 4 or Figures 5 and 6 of the accompanying drawings.