Internal-combustion engines – Charge forming device – Crankcase vapor used with combustible mixture
Reexamination Certificate
2001-10-02
2003-08-05
McMahon, Marguerite (Department: 3747)
Internal-combustion engines
Charge forming device
Crankcase vapor used with combustible mixture
Reexamination Certificate
active
06601572
ABSTRACT:
BACKGROUND OF INVENTION
This invention relates to an internal combustion engine and more particularly to a crankcase ventilating system for internal combustion engines.
In order to reduce the emission of unwanted hydrocarbons and other combustible material to the atmosphere from internal combustion engines, it has been the practice to ventilate the crankcase of the engine by the blow-by gases that pass across the piston rings and into the crankcase chamber. These blow-by gases are then collected and returned by a crankcase ventilating system that normally utilizes a positive crankcase ventilating (PCV) valve to the induction system of the engine. Thus these gases are returned to the combustion chamber and further combustion of the undesirable constituents occurs.
A problem with this type of positive crankcase ventilating system is that when the gases are returned to the induction system and under low ambient temperatures, not only is the induction system but the entire engine at a relatively low temperature, particularly when it is initially started. Since the ventilating gases also include a fair amount of water vapor, they can not only condense but also can solidify in the crankcase ventilating conduit and cause significant problems.
This problem may be best understood by reference to
FIG. 1
, which is a partial cross sectional view showing the conventional type of crankcase ventilating system. The engine, indicated generally by the reference numeral
11
, is provided with an internal crankcase ventilating system which includes an arrangement for returning blow-by gases to an area such as the valve cover
12
which is provided with an oil separator, shown partially at
13
, for returning lubricant to the crankcase. The gases exist the cam chamber enclosed by the cam cover
12
through a first metallic fitting
14
onto which one end of a flexible hose
15
is positioned. The opposite end of the flexible hose
15
is connected to a further fitting
16
, which communicates with the interior of an air inlet device
17
that collects atmospheric air for delivery to the engine combustion chambers.
Because of the aforenoted problems in connection with condensation and freezing, an insulating sleeve
18
frequently is employed encircling the flexible conduit
15
in the area between the metallic fittings
14
and
16
. In spite of this insulation, water vapor in the blow-by gases, which flow in the direction of the arrow shown in this figure, can condense particularly in the area where the fitting
16
joins the air inlet device
17
. Thus, ice particles indicated at
19
can form in this area and either restrict or in extreme cases totally cut off the re-circulating air flow. Various arrangements have been proposed for attempting to avoid this problem, but they have not been totally effective and in many instances can be expensive.
It is, therefore, a principle object to this invention to provide an improved crankcase ventilating system for an internal combustion engine.
It is a specific object to this invention to provide a simple and effective heat insulating arrangement for connecting the crankcase ventilating tube to the induction system of the engine that will provide adequate insulation to preclude the likelihood of freezing even under extremely low ambient temperatures.
SUMMARY OF INVENTION
This invention is adapted to be embodied in an internal combustion engine and crankcase ventilating system therefore. The engine includes an induction system for collecting atmospheric air and delivering the collected air to at least one combustion chamber of the engine. A crankcase ventilating system collects and exhausts blow-by gases from the engine and returns them to the combustion chamber through the induction system for reducing undesirable emissions to the atmospheric. This crankcase ventilating system communicates with the induction system through a fitting having a double wall construction comprised of an inner tube received in an outer tube with the outer wall of the inner tube being circumferentially spaced from the inner wall of the outer tube for heat insulation of the blow gases and inner tube.
REFERENCES:
patent: 4205642 (1980-06-01), Nishimura et al.
patent: 5551409 (1996-09-01), Sanders
patent: 5761905 (1998-06-01), Yamada et al.
patent: 5884612 (1999-03-01), Takeyama et al.
patent: 3932300 (1991-04-01), None
patent: 0503580 (1992-09-01), None
patent: 0816666 (1998-01-01), None
European Search Report dated Feb. 11, 2002.
Patent Abstracts of Japan vol. 1999, No. 09, Jul. 30, 1999 & JP 11 093635A (Kubota Corp), Apr. 6, 1999.
Patent Abstracts of Japan vol. 1999, No. 03, Mar. 31, 1999 & JP 10 331621A (Suzuki Motor Corp), Dec. 15, 1998.
Patent Abstracts of Japan vol. 2000, No. 25, Apr. 12, 2001 & JP 2001 214995A (Pacific Ind Co Ltd), Aug. 10, 2001.
Beutler Ernest A.
McMahon Marguerite
Yamaha Hatsudoki Kabushiki Kaisha
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