Air intake device for an engine

A number of embodiments of compact high efficiency induction systems for an internal combustion engine. In each embodiment, the induction system includes a first pipe section that extends from the respective intake passage of the engine and which terminates in a downwardly turned right angle section. A U shaped pipe section is interconnected at one end to this right angle section and its other end is served by a plenum chamber that is integrally formed with the first pipe section. In some embodiments, the plenum chamber lies at least in part over the first pipe section and in other embodiments it is forwardly of it. In some embodiments, the U shaped pipe section is detachably connected to the plenum chamber, first pipe section assembly so as to permit attachment of different length sections for tuning for different engines.

BACKGROUND OF THE INVENTION 
This invention relates to an air intake device for an engine and more 
particularly to an improved high efficiency and compact induction system 
for an engine. 
It is well known that the efficiency of the induction system of an internal 
combustion engine can be significantly improved by tuning the length of 
the intake passages which serve the individual intake ports. Also, it is 
known that the induction system efficiency can be improved by providing a 
common plenum chamber that serves all of the intake passages or at least 
groups of them so as to reduce cylinder to cylinder variations. However, 
the provision of tuned intake passages and a plenum chamber can give rise 
to obvious spatial difficulties. This problem is particularly acute in 
motor vehicle applications wherein the engine compartment tends to be very 
compact due to the number of accessories and ancillary components of the 
vehicle which are mounted therein. Also, the induction system should be 
arranged in such a way so that there will be adequate air flow across the 
induction system so that the induction system does not become heated and 
reduce the volumetric efficiency of the engine. Previously proposed 
induction systems have not been fully capable of meeting all of these 
requirements. 
For example, it has been proposed to provide a serpentine shaped intake 
passage for each intake port so as to increase the length of the intake 
passages. Such an arrangement, however has necessitated the wrapping of 
the intake passages around the plenum chamber and thus preventing its 
adequate cooling. 
It is, therefore, a principal object of this invention to provide an 
improved, compact, high efficiency induction system for an engine. 
It is a further object of this invention to provide an induction system for 
an engine in which long intake runners can be employed along with a plenum 
chamber and yet a compact and adequately cooled construction results. 
In addition to the difficulties aforenoted, the complex configurations of 
previously proposed induction systems have made them very expensive to 
manufacture. It is, therefore, a still further object of this invention to 
provide an improved induction system for an engine that can be easily and 
inexpensively manufactured. 
In connection with the tuning of the intake system, frequently it may 
become desirable to tune a given engine in a different manner by changing 
the length of the intake passages. With previously proposed constructions, 
this has necessitated the complete replacement of the entire induction 
system. 
It is, therefore, a still further object of this invention to provide an 
improved, compact, efficient induction system wherein the length of the 
intake passages can be easily changed to suit particular applications. 
As has been previously noted, the engine compartment frequently contains a 
number of accessories and ancillary components not only for the engine, 
but also for the associated motor vehicle. Frequently, many of these 
accessories must be driven from the engine and this further complicates 
the positioning and design of the induction system. 
It is, therefore, a still further object of this invention to provide an 
improved, high efficiency induction system for an engine that is compact 
and which yet will afford adequate space for accessories driven by the 
engine. 
SUMMARY OF THE INVENTION 
This invention is adapted to be embodied in an induction system for an 
engine having a plurality of aligned intake ports facing in a first 
direction. The induction system is comprised of a plurality of first pipe 
sections extending from the respective intake port outwardly and 
terminating in a generally right angle portion. A plurality of second pipe 
sections having a generally U shaped configuration are each connected at 
one end thereof to the right angle portion of a respective of the first 
pipe sections. A common plenum chamber is connected to and communicates 
with the other end of each of the first pipe sections for supplying intake 
air to each of the intake ports.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
Referring in detail first to FIG. 1, a motor vehicle is shown, partially 
and is identified generally by the reference numeral 21. The invention is 
described in conjunction with a motor vehicle because it has particular 
utility in such applications, particularly those in which the engine is 
positioned transversely in the engine compartment. Of course, it will be 
understood by those skilled in the art that the invention and certain 
facets of it may be utilized in conjunction with other applications for 
internal combustion engines. 
The motor vehicle 21 has an engine compartment 22 that is defined in part 
by a forwardly sloping hood 23 and fire wall 24 which separates the engine 
compartment 22 from a passenger compartment 25. In the illustrated 
embodiment, the engine compartment 22 is positioned at the front of the 
vehicle and since the invention deals with the engine and its placement in 
the engine compartment, only this portion of the vehicle has been 
illustrated. It is to be understood, however, that the invention also has 
utility in conjunction with other engine placements such as mid or rear 
engine. 
A grill opening 26 is provided at the front of the vehicle 21 for admitting 
cooling air to the engine compartment 22 and a radiator (not shown) 
contained therein. Mounted to the rear of this radiator is an internal 
combustion engine, indicated generally by the reference numeral 27 and 
constructed in accordance with an embodiment of the invention. The engine 
27 is comprised of a four cylinder in line type, although the invention 
also has utility in conjunction with other cylinder numbers and other 
configurations. Also, the invention can be utilized in conjunction with 
non-reciprocating types of engines. The engine 27 drives a pair of front 
wheels 28 through a suitable transmission and final drive mechanism (not 
shown). 
The engine 27 includes a cylinder block 29 having four aligned cylinder 
bores and terminates in a crankcase portion 31 at its lower end. An oil 
pan 32 is affixed to the crankcase portion 31 and the crankshaft of the 
engine, shown partially at 33, is journaled within this crankcase chamber. 
A cylinder head 34 is affixed to the cylinder block 29 in a known manner 
and has a plurality of forwardly facing intake ports 35 (FIG. 2) which are 
generally aligned. There may be one or more intake ports 35 for each 
cylinder of the engine. Intake valves (not shown) are provided at the ends 
of the intake ports 35 and are operated by means of an overhead mounted 
camshaft 36 in a well known manner. 
The engine 27 also has rearwardly facing exhaust ports (not shown) to which 
an exhaust manifold 37 is affixed for discharging the exhaust gases to the 
atmosphere. An exhaust camshaft 38 operates the valves associated with 
these exhaust ports. 
The intake camshaft 36 and exhaust camshaft 38 are driven by a chain or 
toothed belt 39 that is wound around a sprocket 41 affixed to the 
crankshaft 33 and respective sprockets 42 and 43 that are affixed to the 
intake and exhaust camshafts 36 and 37, respectively. A timing case 44, 
which is shown in phantom in FIG. 1 and in solid lines in FIG. 2, is 
affixed to the front of the engine for containing the cam driving 
mechanism. The camshafts 36 and 38 are also enclosed by means of a cam 
cover 45 that, is affixed to the top of the cylinder head 34. 
Spark plugs 46 are carried by the cylinder head 34 and are accessible 
through openings in the cam cover 45. The spark plugs 46 are fired by a 
suitable ignition system. 
The induction system for supplying the fuel air charge to the cylinder head 
intake ports 35 will now be described with respect to this embodiment in 
detail by particular reference to FIGS. 2 and 3 in addition to FIG. 1. 
This induction system is identified generally by the reference numeral 47 
and is comprised of a plurality of individual first pipe sections, 
indicated by the reference numeral 48, which extend in a generally 
horizontal direction forwardly from the individual intake ports 35 toward 
the air inlet opening 26 of the engine compartment. The first pipe 
sections 48 terminate in right angle bent portions 49 that turn in a 
downward direction. The outlet ends of the sections 48 are attached by 
means of flanges 51 to the intake side of the cylinder head. The right 
angle sections 49 have, in turn, flanges 52 that form an attachment to a 
generally U shaped pipe section, indicated generally by the reference 
numeral 53. 
The pipe section 53 has a generally vertically extending portion 54, a 
reentrant curved portion 55 and a further vertically extending section 56. 
It should be noted that the vertically extending sections 56 are staggered 
slightly rearwardly relative to the sections 54 as best shown in FIG. 2. 
At their upper ends, the sections 56 have flanges 52 that afford 
attachment to further flanges 52 formed integrally with the sections 48. 
There is provided a longitudinally extending plenum chamber 59 which is 
formed integrally with the section 48 but which communicates with the 
section 48 only through the U shaped section 53. Neck portions 61 
communicate the plenum chamber 59 with the individual vertically extending 
sections 56 of the U shaped pipes 53. A throttle body 62 is affixed to one 
end of the plenum chamber 59 and contains a throttle valve 63 for 
controlling the flow of air into the plenum chamber 59 and, accordingly, 
the speed of the engine. The throttle body 62 communicates with an air 
cleaner (not shown) through a connecting pipe 64. 
Individual fuel injectors 65 are mounted in the pipe sections 48 adjacent 
the intake ports 35 and deliver a fuel charge thereto in a known manner. 
Because of the fact that the manifold assembly 47 is formed from two parts, 
the part 48 including the plenum chamber 59 and the U shaped parts 53, 
which are connected along a common plane defined by the flanges 52, it can 
be conveniently formed in a very inexpensive manner. Also, it can be 
readily apparent that the length of the intake passages can easily be 
changed by changing the U shaped sections 53 from a long section, as shown 
in solid in FIG. 3, to a shorter section, as shown in phantom in this 
figure. This offers a greater degree of versatility. 
In the embodiment thus far described, it should be noted that the plenum 
chamber 59, although integrally formed with the pipe section 48, is not 
obscured by it and also has a relatively low height. In the illustrated 
embodiment, the plenum chamber 59 is positioned below the top of the cam 
cover 45 of the associated engine. If desired, the plenum chamber 59 can 
be positioned at a somewhat higher elevation but still below the top of 
the engine 27. Such an arrangement is shown in the phantom line view of 
FIG. 3. Because of the orientation of the plenum chamber 59 and the fact 
that it is not obscured, the air flowing through the grill opening 26 can 
readily cool the plenum chamber 59 and the entire induction system and 
thus a high volumetric efficiency can be achieved. 
In the embodiment of FIGS. 1 through 3, the plenum chamber 59 was formed 
integrally with the pipe sections 48, but was positioned rearwardly from 
the right angle bent portions 49 in relation to the engine compartment 22. 
In addition, the plenum chamber 59, pipe section 48 and pipe section 53 
were formed from two separate pieces. FIGS. 4 and 5 show another 
embodiment of the invention which is basically the same as the embodiment 
of FIGS. 1 through 3. In this embodiment, however, the plenum chamber 59 
is formed forwardly of the right angle portion 49 of the pipe section 48 
and the entire assembly is formed from a unitary casting. Because of the 
other similarities of this embodiment to the previously described 
embodiment, all components which are the same in function have been 
identified by the same reference numerals. Further description of this 
embodiment is believed to be unnecessary. 
FIGS. 6 through 11 show another embodiment of the invention which is 
generally the same as the embodiment of FIGS. 1 through 3 and, for that 
reason, the elements of this embodiment which are substantially the same 
as those of the previously described embodiment have been identified 
generally by the same reference numerals. This embodiment, however, shows 
further details of the engine and the accessories driven by it and how the 
induction system can be tailored so as to clear the accessories and 
provide clearance without adversely effecting the performance. In this 
embodiment, there are further internal details of the engine shown and the 
engine is identified generally by the reference numeral 101 while the 
induction system is identified generally by the reference numeral 102. 
FIG. 7 shows a partial cross section of the engine. In this figure there 
can be seen the intake valves 103, exhaust valves 104 and exhaust ports 
105. In addition, one of the pistons 106 is also illustrated. A water pump 
107 is driven off the main timing belt 39 and supplies to a cooling jacket 
108 of the engine 101 in a known manner. 
In addition to the sprocket 41 that drives the timing belt 39, there is 
connected to the crankshaft 33 a further sprocket 109 that drives an 
accessory drive belt 111 which drives further accessories such as an 
alternator or generator 112. A still further accessory drive belt 113 
drives other accessories such as an air conditioning compressor 114 and an 
oil pump 115. These components are disposed as shown in FIGS. 6 and 7. 
It will be noted that the oil pump 115 and air conditioning compressor 114 
are disposed on the intake side of the engine and at the front of it. In 
order to provide clearance, therefore, the first pipe sections 48 emanate 
from the intake ports 35 and are angled rearwardly as may be best seen in 
FIGS. 6 and 8. As a result, the U shaped pipe sections 53 are positioned 
rearwardly of the engine and again are staggered so that the section 54 is 
disposed rearwardly of the section 56 to provide added clearance. Thus, it 
should be readily apparent that the arrangement offers all of the 
advantages of the previously described embodiments, including the two 
piece construction of the embodiment of FIGS. 1 through 3 and still 
further offers clearance for the accessories of the engine and other 
vehicle accessories driven by the engine. 
It should be readily apparent from the forgoing description that the 
embodiments of the invention are particularly adapted at providing a very 
high efficiency induction system that has long intake runners but which 
can be tuned to varying lengths by replacing the U shaped pipe sections 
while still maintaining a compact assembly, one which is easily formed and 
one which offers ease of accessibility and clearance for the components. 
Although a number of embodiments of the invention have been illustrated 
and described, various changes and modifications may be made without 
departing from the spirit and scope of the invention, as defined by the 
appended claims.