CLIAMS:We Claim:

1. An apparatus for withdrawing vapor from an internal combustion engine (10), said apparatus comprising:
a vapor duct (60) comprising an upstream end (65) and a downstream end (70), said upstream end (65) in fluid communication with an outlet of said internal combustion engine (27), said downstream end (70) in fluid communication with an engine inlet manifold (48);
characterized in that a flow pump (82) located in said vapor duct (60), said flow pump (82) adapted to operate when pressure in said internal combustion engine (27) is lesser than pressure at said downstream end (70) of said vapor duct (60).
2. The apparatus in accordance with Claim 1, comprising a bypass vapor duct (88), said bypass vapor duct (88) in fluid communication between said upstream end (65) of said vapor duct (60) and said downstream end (70) of said vapor duct (60).
3. The apparatus in accordance with Claim 2, comprising a fluid inlet valve (33) located in said bypass vapor duct (88).
4. The apparatus in accordance with Claim 3, comprising a control unit (95) coupled to said fluid inlet valve (33), said control unit (95) adapted to actuate said fluid inlet valve (33) to facilitate channeling vapor through said bypass vapor duct (88) when pressure in said internal combustion engine (27) is greater than or equal to pressure at said downstream end (70) of said vapor duct (60).
5. The apparatus in accordance with Claim 4, wherein said control unit (95) is coupled to said flow pump (82), said control unit (95) adapted to operate said flow pump (82) when pressure in said internal combustion engine (27) is lesser than pressure at said downstream end (70) of said vapor duct (60).
6. A method for withdrawing vapor from an internal combustion engine (27), said method comprising:
coupling an upstream end (65) of a vapor duct (60) to the internal combustion engine (27) and a downstream end (70) to an engine inlet manifold (48) characterized in that
coupling a flow pump (82) to the vapor duct (60); and
operating said flow pump (82) to withdraw vapor from the internal combustion engine (27) when pressure in the internal combustion engine (27) is lesser than pressure at a downstream end (70) of the vapor duct (60).
7. The method in accordance with Claim 6, wherein the flow pump (82) is adapted to operate at a speed that is a function of a pressure difference between pressure at the downstream end (70) of the vapor duct (60) and pressure in the internal combustion engine (27).
,TagSPECI:Field of the invention:
[001] This invention relates to an apparatus for withdrawing vapor and an engine crankcase thereof.

Background of the invention:
[002] Blow-by gas from an engine crankcase is recirculated to an engine inlet manifold through a positive crankcase ventilation valve. At high altitudes, air entering the engine inlet manifold from an engine test rig through an air filter is at a higher pressure than a pressure of the blow-by gas that is channelled from the engine crankcase. The high pressure air entering the engine inlet manifold from the air filter causes the blow-by gas to be pressured back towards the engine crankcase. This phenomenon results in an increase of engine crankcase pressure thereby leading to improper draining of lubricating oil to a crankcase oil sump.
[003] U.S. Patent Number 5,890,475 discloses a crankcase ventilation system that withdraws vapor from the crankcase of an internal combustion engine thereby moving the vapor along with a controlled amount of bleed air to the inlet manifold of the engine. A bleed inlet tube is located adjacent to a crankcase outlet tube for combining bleed air with vapor from the crankcase, and directing the bleed air and vapor from the crankcase to the inlet manifold of the engine.

Brief description of the accompanying drawings
[004] An exemplifying embodiment of the invention is explained in principle below with reference to the drawings. The drawings are,
[005] Figure 1 illustrates a schematic of an apparatus for withdrawing vapour from an internal combustion engine according to one embodiment of the invention.

Detailed Description of the invention:
[006] Engine crankcase vapors are continuously circulating through the engine crankcase. Blow-by gas formed from incomplete combustion of air/fuel is introduced into the engine crankcase as a result of some leakage past a set of piston rings with each compression and power stroke. The blow-by gas needs to be removed at the same rate from the engine crankcase to prevent pressure from building up within the engine crankcase.
[007] As shown in Figure 1, an apparatus for withdrawing vapor from an internal combustion engine 10 is disclosed. The apparatus comprises a vapor duct 60 comprising an upstream end 65 and a downstream end 70, the upstream end 65 in fluid communication with an outlet of an internal combustion engine 27, the downstream end 70 in fluid communication with an engine inlet manifold 48 characterized in that a flow pump 82 located in the vapor duct 60, the flow pump 82 adapted to operate when pressure in the internal combustion engine 27 is lesser than pressure at the downstream end 70 of the vapor duct 60.
[008] A method for withdrawing vapor from an internal combustion engine 27 is discussed. The method comprises coupling an upstream end 65 of a vapor duct 60 to an internal combustion engine 27, and a downstream end 70 to an engine inlet manifold 48 characterized in that coupling a flow pump 82 to the vapor duct 60 and operating the flow pump 82 to withdraw vapor from the internal combustion engine 27 when pressure in the internal combustion engine 27 is lesser than pressure at the downstream end 70 of the vapor duct 60.
[009] The internal combustion engine 27 includes a cylinder head 20 installed on an upper end portion of a cylinder block 12, and a head cover 18 attached to an upper end of the cylinder head 20. A cylinder 15 is provided in the cylinder block 12. A piston 25, which reciprocates, is housed in the cylinder 15. The piston 25 is connected to a crankshaft 30 through a connecting rod 17 to transmit power. Further, an engine crankcase 40 is coupled to a lower portion of the cylinder block 12. A space that extends inside the engine crankcase 40 constitutes a crank chamber 42. An oil sump 45 where oil is accumulated is provided at a bottom portion of the engine crankcase 40.
[0010] An inlet manifold 48 is connected to the cylinder head 20. The downstream portion of the inlet manifold 48 is connected to the cylinder head 20. An upstream portion of the inlet manifold 48 is connected to a turbocharger 36. A downstream end of an air inlet passageway 80 is coupled to the turbocharger 36. An air filter 50 is coupled to an upstream end of the air inlet passageway 80.
[0011] Thus air introduced into the turbocharger 36 from the air filter 50 through the air inlet passageway 80 is introduced into the inlet manifold 48. A fuel injector (not shown) is provided in the cylinder head 20. Air introduced from the inlet manifold 48 is mixed with fuel injected from the fuel injector to form an air-fuel mixture.
[0012] The blow-by gas flows into the engine crankcase 40 through a gap between an inner surface of the cylinder 15 and an outer surface of the piston 25. The blow-by gas introduced into the engine crankcase 40 is drawn out of the engine crankcase 40 through a vapor duct 60. More specifically, the solid arrows indicate the manner in which the blow-by gas is drawn out of the engine crankcase 40 and channeled to the vapor duct 60.
[0013] Blow-by gas is channeled from the upstream end 65 of the vapor duct 60 to the downstream end 70 of the vapor duct 60. More specifically, the upstream end 65 of the vapor duct 60 is in fluid communication to the cylinder head cover 18, and the downstream end 70 of the vapor duct 60 is in fluid communication to the air inlet passageway 80 and is adapted to channel blow-by gas therethrough to the air inlet passageway 80. In the embodiment shown in Figure 1, the downstream end 70 of the vapor duct 60 is in flow communication to the air inlet passageway 80 between the air filter 50 and the turbocharger 36.
[0014] As shown in Figure 1, vapor duct 60 is coupled to an oil filter 66. The oil filter 66 is coupled downstream from the head cover 18 and filters oil/particulate matter from the blow-by gas that is drawn out of the engine crankcase 40. The filtered blow-by gas from the oil filter 66 is channeled through the vapor duct 60 to the flow pump 82.
[0015] Flow pump 82 is adapted to increase pressure and therefore control a flow of blow-by gas supplied through the vapor duct 60. Flow pump 82 is adapted to increase pressure of blow-by gas supplied from the oil filter 66 and deliver it to the downstream end 70 of the vapor duct 60. The flow pump 82 is adapted to operate at a speed that is a function of a pressure difference between pressure in the air inlet passageway 80 and pressure in the engine crankcase 40. In the embodiment, flow pump 82 is a manual/automated flow rate adjustable pump that is adapted to control the flow rate of blow-by gas from the oil filter 66 to the downstream end 70 of the vapor duct 60.
[0016] In an embodiment, vapor duct 60 further includes a bypass vapor duct 88. Bypass vapor duct 88 is a part of the apparatus for withdrawing vapor from an internal combustion engine 10 such that a first end 92 thereof is positioned downstream from the upstream end 65 of the vapor duct 60 and a second 94 thereof is positioned upstream from the downstream end 70 of the vapor duct 60. The first end 92 and second end 94 of the bypass vapor duct 88 in flow communication with the vapor duct 60. Blow-by gas is channeled from the first end 92 of the bypass vapor duct 88 to the second end 94 of the bypass vapor duct 88 when the flow pump 82 is not operational. More specifically, blow-by gas is channeled from the first end 92 of the bypass vapor duct 88 to the second end 94 of the bypass vapor duct 88 when pressure of blow-by gas at the upstream end 65 of the vapor duct 60 is greater than or equal to pressure of air drawn from the air filter 50 and delivered to the air inlet passageway 80.
[0017] In an embodiment, the apparatus for withdrawing vapor from an internal combustion engine 10 comprises a fluid inlet valve 33. In an embodiment, fluid inlet valve 33 may be actuated by a manual/automated mechanism for controlling the flow rate of blow-by gas channeled through the fluid inlet valve 33. The fluid inlet valve 33 is coupled to the bypass vapor duct 88 for controlling the flow of blow-by gas from the first end 92 of the bypass vapor duct 88 to the second end 94 of the bypass vapor duct 88.
[0018] The apparatus for withdrawing vapor from an internal combustion engine 10 includes a control unit 95. Control unit 95 is adapted to be coupled to the flow pump 82 through a control path 97, and is adapted to operate the flow pump 82 to facilitate channeling blow-by gas through the vapor duct 60. The control unit 95 is adapted to control the flow pump 82 and increase pressure of blow-by gas supplied to the downstream end 70 of the vapor duct 60 when pressure of blow-by gas at the upstream end 65 of the vapor duct 60 is lesser than pressure of air drawn from the air filter 50 and delivered to the air inlet passageway 80. In a further embodiment, the control unit 95 is adapted to turn off the operation of the flow pump 82 when pressure of blow-by gas at the upstream end 65 of the vapor duct 60 is greater than or equal to pressure of air drawn from the air filter 50 and delivered to the air inlet passageway 80.
[0019] Control unit 95 is further adapted to be coupled to the fluid inlet valve 33 via a control path 89. In the embodiment, control unit 95 is adapted to actuate the fluid inlet valve 33 to an open position to facilitate channeling blow-by gas through the bypass vapor duct 88 when pressure of blow-by gas at the upstream end 65 of the vapor duct 60 is greater than or equal to pressure of air drawn from the air filter 50 and delivered to the air inlet passageway 80. In a further embodiment, the control unit 95 is adapted to actuate the fluid inlet valve 33 to a closed position when pressure of blow-by gas at the upstream end 65 of the vapor duct 60 becomes lesser than pressure of air drawn from the air filter 50 and delivered to the air inlet passageway 80.
[0020] The operation of the apparatus for withdrawing vapor from an internal combustion engine 10 is now described. When the apparatus for withdrawing vapor from an internal combustion engine 10 is in use, the piston 25 reciprocates within the cylinder 15. With each stroke of the piston 25, the blow-by gas formed within a cylinder bore is introduced into the engine crankcase 40 as a result of leakage past the set of piston rings. The blow-by gas introduced into the engine crankcase 40 is at a lower pressure relative to the air channeled to the inlet manifold 48 through the air filter 50 from a test rig (not shown). The blow-by gas introduced into the engine crankcase 40 requires to be pressurized to prevent a backflow of blow-by gas into the engine crankcase 40. The control unit 95 activates the flow pump 82, thereby pressurizing the blow-by gas channeled from the engine crankcase 40 to a pressure greater than or equal to pressure of air channeled from the air filter 50 to the air inlet passageway 80. Thus a backflow of blow-by gas into the engine crankcase 40 by the air channeled from the air filter 50 is prevented.
[0021] As pressure of blow-by gas in the engine crankcase 40 increases to a pressure equal to or greater than pressure of air channeled from the air filter 50, the flow pump 82 is deactivated by the control unit 95. The control unit 95 activates the fluid inlet valve 33 to an open position to facilitate channeling pressurized blow-by gas from the engine crankcase 40 through the bypass vapor duct 88 to the downstream end 70 of the vapor duct 60. Thus the flow pump 82 and fluid inlet valve 33 are alternatively operated and controlled by the control unit 95 to facilitate channeling blow-by gas from the engine crankcase 40 to the inlet manifold 48 through the air inlet passageway 80.
[0022] The above described apparatus for withdrawing vapor from an internal combustion engine 10 is cost effective and highly reliable. The apparatus for withdrawing vapor from an internal combustion engine 10 facilitates blow-by gas from the internal combustion engine 27 to be delivered to the inlet manifold 48 through the flow pump 82 or through the bypass vapor duct 88 depending on whether pressure of the blow-by gas in the engine crankcase is lesser than or greater than pressure of air channeled from the air filter 50. In addition, the modular nature of each sub-system of the apparatus for withdrawing vapor from an internal combustion engine 10 facilitates easy disassembly and replacement of individual system components as required.
[0023] It must be understood that the embodiments explained in the above detailed description in only illustrative and does not limit the scope of this invention. The scope of this invention is limited only by the scope of the claims. Many modification and changes in the embodiments aforementioned are envisaged and are within the scope of this invention.