the internal combustion engine which is illustrated as the exemplary embodiment is a two - cylinder fuel injection internal combustion engine having almost vertically standing cylinder housings 10 secured to the crankcase housing 12 . a support plate 16 is inserted between the cylinder heads 14 and the cylinder housing 10 and on which support plate is releasably mounted the individual elements of the engine casing which extends downwardly , as discussed in detail for example in u . s . pat . no . 3 , 924 , 597 . a sound absorbing shell 18 is mounted above the machine and is also releasably secured to the support plate 16 . a profiled plate 20 is attached to the shell and forms a downwardly opening air inlet channel ( a ) for cooling air . a shell - shaped baffle 22 is mounted on the remote side of the engine and receives air from the channel defining plates 16 , 18 , 20 and diverts same to an air cooling blower 24 . the impeller 24a of the blower has a blower shaft 24b and is driven through a belt 28 by a drive pulley 26 which is positioned on the crankshaft of the engine . the cooling air which is drawn in is moved through a stationary guide wheel 24c by the blower against the cylinder housings 10 and further into the inside of the casing . after flowing around the encased engine body , the now hot air enters an outlet channel which is formed by a downwardly open sheet - metal casing 30 and leaves the casing through the outlet ( b ). combustion air is fed to the two cylinders in the cylinder housings 10 through an intake elbow duct 32 , while the burnt gases are guided into an exhaust chamber which is provided outside of the casing , which exhaust chamber is here surrounded by a special casing 33 which is used for dampening sounds and which is discussed more in detail in u . s . patent application ser . no . 712 , 778 , filed aug . 9 , 1976 . the burnt gases exit from the exhaust chamber 33 to the outside through an exhaust pipe 35 . combustion air is fed to the intake elbow 32 from an air filter 34 which is covered by an inverted pot - shaped sheet - metal housing 36 . the housing defined by the pot 36 is closed off by an annular gasket 38 which is positioned on the support plate 16 so that within the housing 36 a chamber is defined . an air - funnellike pipe 40 extends from this chamber to the inside of the engine casing . the pipe 40 is connected to the support plate 16 in a manner not illustrated in detail such that the air entrance into the inside of the housing 36 is possible only through the port 40m of the pipe 40 . the port 40m is surrounded by a semicircular shielding plate 42 ( fig3 ) which is secured to the crankshaft housing 12 and is open toward the adjacent shell of the engine casing . it can clearly be seen that in the case of this arrangement , the combustion air flowing to the air filter 34 from the inside of the casing travels only through the port 40m of the pipe 40 . the intake noise which occurs in the air filter 34 during operation is outwardly limited or dampened from the casing because the filter housing 36 which is exposed to the sound from the engine body is almost entirely surrounded by the sound dampening shells and this double wall construction effects a large reduction in the sound level . the still possible direct exit of noise from the engine body through the inlet or outlet openings of the casing ( at 20 or 30 ) is subjected also to an additional amount of dampening which results from the many deflections of the sound waves and furthermore is based on the action of sound - absorbing rock wool layers within the guide channels which extend from the filter housing 36 to the mentioned openings . the noise from the air filter 34 , which during the intake function is also created and which is transmitted through air vibrations , is subjected to a first reduction in volume in the housing 36 itself . a further reduction occurs through the deflection through the pipe 40 and through the considerable length of this pipe . finally a further reduction results from the connection of the two air volumes in the filter housing 36 and within the engine casing through the narrow pipe 40 , through which these air spaces can swing to one another ( interference phenomenon ). the oscillations which then still occur at the port 40m of the pipe 40 and are already much reduced in the above discussed manner can exit from the engine casing mostly only on the following main passageways : 1 . 1 flowing through the narrow gap between crankshaft housing 12 and casing , wherein multiple deflections at approximately 90 ° occur . 1 . 2 flowing through the inbetween connected large space for the starter 43 . 1 . 3 deflecting into the outlet channel 30 and multiple deflection within said long channel , which is furthermore coated with sound - absorbing rock wool layers . 2 . 1 passing through the narrow cooling ribs of the cylinder housings 10 . 2 . 2 multiple deflection through the cylinder encasing pieces 44 which are illustrated in fig4 and are , if desired , inserted . 2 . 3 deflection into the outlet channel 30 and multiple deflections within said channel , which is designed in the discussed manner . 3 . 5 passing through the inlet channel a , which is coated with sound - absorbing rock wool layers . it can clearly be seen that the sound waves which exit at the port 40m of the pipe 40 are subjected to a plurality of obstacles on these three main routes which lead to the outside of the casing , which obstacles cause a considerable dampening of the long - wave length , low frequency intake oscillations because many of the deflections and reflections include surfaces having sound - absorbing layers and different sized chambers which are connected one behind the other ( interference phenomena ) and finally narrow passages or blower grills . in this manner , the inventive arrangement of the air inlet to the filter dampens the intake noise very much and in such a manner that , together with the engine casing , a sound dampening device is obtained , which at a minimum structural expense achieves a total efficiency fully meeting the set requirements . although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes , it will be recognized that variations or modifications of the disclosed apparatus , including the rearrangement of parts , lie within the scope of the present invention .