Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02949792 2016-11-24
CRANKCASE EVACUATION DEVICE
Field of Invention
This invention relates to the evacuation of blow-by gas from the crankcase of
an internal
combustion engine, and more particularly to a device for evacuation of the
blow-by gas from the
internal combustion engine.
Background to the Invention
A fuel and air mixture is fed into each of the one or more combustion
cylinders of an internal
combustion engine, compressed by a piston and ignited. The ignition of the
compressed fuel and
air mixture causes a controlled explosion within the combustion chamber which
drives the piston
within the combustion chamber in a direction opposite to the direction of
compression, towards a
crankshaft housed in a crankcase below the bottom end of the combustion
cylinder. Gas created
by the controlled explosion (combustion gas) is exhausted from the top end of
the combustion
cylinder, and the cycle is then repeated continuously while the engine is
running.
While most of the combustion gas is exhausted from the top end of the
combustion cylinder, a
small portion of the combustion gas leaks past the piston in the cylinder and
passes into the
crankcase below the bottom end of the combustion cylinder. This leaked gas is
known in the art
as blow-by gas. Oil, contained within the crankcase, lubricates the crankshaft
and other moving
parts of the engine as the engine is running. Blow-by gas can build up in the
crankcase, if the
crankcase is closed. The pressure of the built up blow-by gas can hasten the
deterioration of the
oil in the crankcase over time, and eventually the pressurized blow-by gas
will pass out of the
crankcase through gaskets and seals in the engine, together with some of the
oil, thereby creating
a mess on the exterior surfaces of the engine.
To avoid this mess, modern internal combustion engines are vented, allowing
exhaustion of
blow-by gases from the crankcase in an orderly manner. One way of venting the
crankcase is by
feeding air from the engine's air cleaner to the crankcase through a duct
called a breather, The
air fed through the crankcase is exhausted from the crankcase (together with
any built-up blow-
by gas) through a device called a PCV valve (positive crankcase ventilation
valve). The PCV
valve is held open by a vacuum line which returns the blow-by gas, together
with air vented
1
CA 02949792 2016-11-24
through the crankcase by the breather, to the engine's intake manifold so it
can be mixed with
fuel to form the air-fuel mixture which is fed into the combustion cylinders
of the engine.
However, in a system utilizing the PCV valve, suction created using a manifold
vacuum in the
traditional manner deteriorates as engine throttle is opened and the engine
speed is increased. In
other words, as more pressure builds within the crankcase (as engine speed
increases), the less
vacuum is available, making the system using the PCV valve work best when the
engine is at
idle speed or slightly off. Additionally, blow-by gas is returned to the
intake manifold, which
contaminates the air-fuel mixture. And, of course, because the vacuum line
holds the PCV valve
open as the engine is running, there are moving parts in the PCV valve that
are under stress and,
consequently, that are subject to deterioration.
The crankcase evacuation device of the present invention, described herein,
may be used as an
alternative to the PCV valve.
Sti ni mar.' of the Invention
According to one aspect of the present invention, there is provided a
crankcase evacuation device
comprising: a sleeve inserted in an interior surface of a passageway
exhausting blow-by gas from
a crankcase of an internal combustion engine, wherein the sleeve comprises: a
body extending
through a portion of the passageway, wherein the body defines a channel
running axially along
the length of the body from a first end of the body, proximal to the
crankcase, to a second end of
the body, distal to the crankcase, and wherein there is an annular lip at each
of the first and
second ends of the body joining each of the first and second ends of the body
to a corresponding
first and second annular surface of the interior of the passageway; and
wherein the channel
comprises two stepped regions comprising a first stepped region running from
the lip at the end
of the body proximal to the crankcase and a second stepped region running from
the lip at the
end of the body distal to the crankcase, wherein the first stepped region is
more narrow that the
second stepped region and wherein there is an annular joint between the first
stepped region and
the second stepped region, wherein the thickness ofthe annular joint in a
plane cross-sectional to
the length of the channel is the difference in narrowness of the first stepped
region and the
second stepped region, and wherein there are a plurality of holes in the
annular joint, and a gas
intake fitting attached to an external surface of the passageway wherein the
fitting supplies a
2
CA 02949792 2016-11-24
stream of gas through a hole in the passageway to a space within the
passageway defined
between the annular lips at each of the first and second ends of the body.
According to another aspect of the present invention, there is provided a
crankcase evacuation
device as described herein, wherein the sleeve and passageway are cylindrical.
According to yet another aspect of the present invention, there is provided a
crankcase
evacuation device as described herein, wherein the plurality of holes in the
annular joint are
spaced at equidistant intervals.
According to still another aspect of the present invention, there is provided
a crankcase
evacuation device as described herein, wherein the plurality of holes is six
holes.
According to a further aspect of the present invention, there is provided a
crankcase evacuation
device as described herein, wherein the stream of gas comes from exhaust gas
of combustion
chambers of the internal combustion engine being expelled from the engine,
exhaust gas of the
combustion chambers of the internal combustion chambers being fed from a
turbocharger, or gas
being fed to the internal combustion engine from a supercharger.
According to yet a further aspect of the present invention, there is provided
a crankcase
evacuation device as described herein, wherein the sleeve is made of aluminum.
According to still a further aspect of the present invention, there is
provided a crankcase
evacuation device as described herein, wherein the aluminum is T6 aluminum.
According to another aspect of the present invention, there is provided a
crankcase evacuation =
device as described herein, wherein each of the plurality of holes in the
annular joint is at an
angle of nine degrees (90) to the second stepped region of the channel.
Brief Description of the Drawings
Figure IA is a side elevational view of the sleeve portion of the crankcase
evacuation device of
the present invention.
Figure IB is a perspective view, viewed from below, of the sleeve portion
illustrated in Figure
1A.
3
CA 02949792 2016-11-24
Figure 2A is a bottom plan view of the annular joint between the first stepped
region and the
second stepped region of the sleeve portion illustrated in Figure 1A.
Figure 2B is a side elevational view, shown in cross section, of a portion of
the sleeve portion
illustrated in Figure IA.
Figure 2C is a side elevational view, shown in cross section, of a portion of
the sleeve portion
illustrated in Figure 1B.
Figure 3 is a side elevational view, shown in cross section, of the crankcase
evacuation device of
the present invention.
Detailed Description of the Invention
Figure 3 shows a crankcase evacuation device 1 of the present invention
installed in a
passageway 10 exhausting blow-by gas from a crankcase of an internal
combustion engine (not
shown) which would be found below the bottom end 12 of passageway 10.
Device 1 comprises sleeve 20 inserted in passageway 10, and a gas intake
fitting 50, attached to
a portion of an external surface of the passageway 10 somewhere between
annular lips 32, 34
found at opposite ends of the sleeve 20, respectively. In the embodiment shown
in Figure 3,
sleeve 20 and passageway 10 are cylindrical tubes with circular cross-
sectional profiles.
However, the skilled person would understand that tubes with non-circular
cross-sectional
profiles could also be used, such as oval-shaped or rectangular-shaped cross-
sectional profiles.
As shown in isolation in Figure 1A, sleeve 20 comprises a body 26 which
defines a channel 28
running axially along the length of the body 26 from a first end 22 of the
body 26, proximal to
the crankcase (not shown) to a second end 24 of the body 26, distal to the
crankcase (not shown).
There is an annular lip 32, 34 at each of the first and second ends 22, 24 of
the body 26,
respectively.
As shown in Figure 3, each of annular lips 32, 34 joins to a corresponding
first and second
annular surface of passageway 10 at joints 42 and 44, respectively, which seal
off a section 16 or
passageway 10 between annular lips 32 and 34. Gas intake fitting 50 attaches
to a portion of an
4
CA 02949792 2016-11-24
external surface of passageway 10 and feeds gas into the sealed-off section 16
of passageway 10
between annular lips 32 and 34.
Body 26 comprises two stepped regions 126, 226 which correspondingly define
two stepped
regions 128, 228 of channel 28. Stepped regions 126 and 128 of body 26 and
channel 28,
respectively, have a more narrow diameter than the diameters of stepped
regions 226 and 228 of
body 26 and channel 28, respectively. There is an annular joint 60 between the
more narrow first
stepped region 126 of body 26 and the less narrow second stepped region 226 of
body 26. The
thickness of the annular joint 60 in a plane cross-sectional to the length of
channel 28 is the
difference in the narrowness of the first stepped region 126 and the second
stepped region 226 of
body 26.
The annular joint 60 has a plurality olholes 80 extending there-through. Each
of the plurality of
holes 80 extends from the interior of the second stepped region 228 of the
channel 28 to a space
between the first stepped region 126 of body 26 and the sealed-off region 16
of passageway 10
between annular lips 32 and 34. In one embodiment, the holes 80 in the
plurality of holes 80 are
spaced at equidistant intervals in annular joint 60. In a further embodiment,
shown in Figure 2A,
there are six holes 80 in annular joint 60, each of which is spaced at an
equidistant interval. The
location of two of these holes 80, on opposite sides of the body 26, arc shown
in Figure 2B. One
of these holes 80 is isolated in a circle drawn in broken lines 62 shown on
the left-hand side of
Figure 2B and represents the cross-sectional view taken along line Y-Y in
Figure 2A. Circled
region 62 is shown in expanded view in Figure 2C, and in the embodiment shown
in Figure 2C,
hole 80 of diameter 6 is bored out at an angle 0 to the longitudinal wall of
channel 28, thereby
making a hole angled in towards the center of channel 28.
To give an idea of the relative proportions of the components of the device 1,
in one
embodiment, the internal diameter of passageway 10 is 1.125 inches, which
matches the
diameter each of annular lips 32 and 34, found at opposite ends of the body 26
of sleeve 20. The
total length of the body 26 is 1.00 inch, with each of annular lips having a
length of 0.125 inch,
so that the sleeve 20 has a total length of 1.250 inches. The first stepped
region 126 of body 26
has a length of 0.275 inch and an external dimeter of 0.900 inch. The second
stepped region 226
of body 26 has a length of 0.725 inch and an external diameter of 1.00 inch.
The difference in
CA 02949792 2016-11-24
the diameters of the first stepped region 126 and the second stepped region
226 means that the
width of annular joint 60 is 0.100 inch. The diameter of each of the plurality
of holes in annular
joint 60 is 0.0625 inch, and angle 0 is 9 degrees.
In one embodiment, sleeve 20 is made out of aluminum, for example T6 aluminum.
In operation, when venting a crankcase (not shown) with an air intake (not
shown), air is
exhausted (together with blow-by gas) through passageway 10. Passageway 10 is
fitted with
crankcase evacuation device 1 such that exhaust leaving the crankcase is free
to flow through
= passageway 10 and device 1, as illustrated by the white arrows in Figure
3.
In order to draw exhaust leaving the crankcase through passageway 10, a vacuum
is created in
crankcase evacuation device 1 in the following manner. Gas is fed through a
line (not shown)
leading to gas intake fitting 50. The gas may be fed from a source that is
able to provide gas
during the operation of the internal combustion engine, such as the exhaust
manifold, or the
turbocharger or supercharger (in engines fitted with a turbocharger or
supercharger,
respectively). The gas is fed through gas intake fitting 50 into sealed-off
section 16 of
passageway 10 between the two annular lips 32 and 34. The only outlet of
sealed-off section 16
is the plurality of holes 80 in the annular joint 60. In an embodiment
previously described, the
diameter of each of the plurality of holes is 0.0625 inch. If the diameter of
the gas intake fitting
50 is larger than that of the holes 80, for example 0.25 inch, gas will be fed
into sealed-off
section 16 and will be forced into the second stepped region 228 of channel 28
under pressure, as
illustrated by the black arrows in Figure 3. The pressurized gas entering the
second stepped
region 228 of channel 28 will create a vacuum in the first stepped region 128
of channel 28,
which will in turn draw the exhaust gas from the crankcase through proximal
end 12 of
passageway 10 to the distal end 14 of passageway 10. From the distal end 14 of
passageway 10,
exhausted gas may be fed through to an exhaust system (not shown) comprising
components
such as a catalytic converter (not shown) to capture impurities and,
ultimately, expelled.
6
