JP2012127254A - Blowby gas return device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blowby gas reflux device whose blowby gas passage has a superior heat-retaining characteristic and which is at a low cost and suffers little risk of being frozen.SOLUTION: A blowby gas return device is disposed with an oil mist separator in an engine side portion opposite to an engine air-intake system, thereby separates oil mist in the blowby gas is separated with the oil mist separator and then returns the blowby gas to the engine air-intake system, wherein a pipe passing through the inside of a plastic valve cover is molded integrally to the valve cover attached over the cylinder head of the engine, the pipe is then connected at its one end to the engine air-intake system, and at its other end connected to the oil mist separator using a piping material comprised of a pipe or tube, and a blowby gas passage through which the blowby gas is flowed down from the oil mist separator to the engine air-intake system is thereby provided.

Description

  The present invention relates to a blow-by gas recirculation device that circulates blow-by gas to an intake system of an engine.

  As the engine is driven, blow-by gas leaks into the crank chamber from the gap between the cylinder and piston. Therefore, as a measure to prevent HC (hydrocarbon) emissions, the closed-by flow of blow-by gas trapped in the crank chamber to the engine intake system Blowby gas recirculation devices of the type are known.

  By the way, since oil mist is mixed in the blow-by gas, this type of blow-by gas recirculation device conventionally has a valve cover (rocker cover) 1 for attaching the blow-by gas from the crank chamber to the upper part of the cylinder head as shown in FIG. The oil mist in the blow-by gas is separated by an oil mist separator provided in the valve cover 1, and the oil mist is separated by an oil mist separator 5 externally attached to the engine 3.

  The blow-by gas from which the oil mist has been separated is recirculated to the intake system 9 of the engine 3 through a blow-by gas passage (blow-by gas recirculation passage) 7 connected to the oil mist separator 5. In view of the layout around the engine 3, the oil mist separator 5 is usually disposed on the side of the engine opposite to the intake system 9. For safety measures such as preventing a vehicle fire, the blow-by gas passage 7 is piped to the intake system 9 through the rear of the cooling fan 13 which is the shortest distance, avoiding the exhaust system 11 around the engine 3.

  However, if the blow-by gas passage 7 is piped behind the cooling fan 13 in this manner, the blow-by gas passage 7 is cooled during operation in an extremely cold environment, and the moisture in the blow-by gas flowing through the inside freezes. In the worst case, the blow-by gas passage 7 may be blocked. If the blow-by gas passage 7 is blocked as described above, the pressure in the crank chamber of the engine 3 increases, and there is a possibility that secondary problems such as oil leakage from each part of the engine may occur.

  Conventionally, in order to prevent the blow-by gas passage from freezing, the blow-by gas passage is covered with a heat retaining pipe through which engine cooling water flows as disclosed in Patent Document 1, and further disclosed in Patent Document 2. Measures are taken such as improving the heat retaining property of the blow-by gas passage by covering the blow-by gas passage with a heat insulation cover.

JP-A-7-166835 No. 1-7208

  However, as described above, in the conventional examples disclosed in Patent Documents 1 and 2, a long heat insulation pipe is separately prepared and piped, and a heat insulation cover is separately prepared and used as a blow-by gas passage. Since it is packaged, the number of parts increases, the structure becomes complicated, and costs increase.

  The present invention has been devised in view of such circumstances, and an object of the present invention is to provide a blow-by gas recirculation device that is excellent in heat retaining properties of the blow-by gas passage and is low in cost and low in freezing risk.

  In order to achieve such an object, according to the present invention, an oil mist separator is disposed on the side of the engine opposite to the engine intake system, and the oil mist in the blow-by gas is separated by the oil mist separator so that the blow-by gas is taken into the engine intake. In a blow-by gas recirculation device for recirculating to the system, a pipe that penetrates the inside of the valve cover is integrally formed with a resin valve cover that is attached to the upper part of the cylinder head of the engine, and one end side of the pipe and the engine intake system And the other end side of the pipe and the oil mist separator are connected by a pipe or tube material to provide a blow-by gas passage through which blow-by gas flows from the oil mist separator to the intake system. To do.

  According to the present invention, even during operation in an extremely cold environment, the blow-by gas passage is not cooled, and the moisture in the blow-by gas flowing through the inside does not freeze. And after an engine stops, a water | moisture content does not accumulate in a blowby gas channel | path.

  In addition, the valve cover may be removed from the cylinder head during maintenance, but the pipe is integrally formed with the valve cover, and pipes such as pipes and tubes are detachably connected to the valve cover. It is easy to assemble the blow-by gas passage.

  Compared to the conventional example of covering the blow-by gas passage with a heat insulation pipe or covering the blow-by gas passage with a heat insulation cover to prevent the blow-by gas passage from freezing, the entire blow-by gas recirculation device has a small number of parts. It has the advantage that it can be a simple and inexpensive system.

It is a top view of the blowby gas recirculation device concerning one embodiment of the present invention. It is a front view of the blowby gas recirculation apparatus shown in FIG. It is a top view of the conventional blow-by gas recirculation apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same parts as those in the conventional example of FIG. 3 are denoted by the same reference numerals.

  1 and 2 show an embodiment of a blow-by gas recirculation device according to the present invention. In the figure, reference numeral 15 denotes a resin valve cover that is attached to the upper part of the cylinder head of the engine 3. An oil mist separator (not shown) is provided inside, and an oil mist separator 5 is separately attached to the side of the engine opposite to the intake system 9 to remove oil mist in the blow-by gas from the valve cover 15. It comes to separate.

  Further, a pipe 17 penetrating the inside of the valve cover 15 in the left-right direction is integrally formed on the tip end side (cooling fan 13 side) of the valve cover 15, and end portions 19 and 21 of the pipe 17 are respectively formed in the valve cover. The left and right side walls 23 and 25 protrude outward.

  A hard pipe 27 (or a soft tube) is detachably connected between one end 19 of the pipe 17 projecting toward the oil mist separator 5 and the oil mist separator 5, and the other end of the pipe 17 is connected. A hard pipe 29 (or a soft tube) is detachably connected between the portion 21 and the intake system 9. In this embodiment, the oil mist separator 5 and the intake system 9 are connected by the pipes 17, 27, and 29. The blow-by gas passage 31 through which the blow-by gas flows is provided between the two.

  The blow-by gas recirculation device 33 according to the present embodiment is configured as described above, and the operation and effect thereof will be described next.

  As the engine 3 is driven, blow-by gas mixed with oil mist leaks into the crank chamber from the gap between the cylinder and the piston, and the blow-by gas is introduced from the crank chamber into the valve cover 15 attached to the upper part of the cylinder head. Then, the oil mist in the blow-by gas is sequentially separated by the oil mist separator in the valve cover 15 and the oil mist separator 5 externally attached to the engine 3.

  The blow-by gas from which the oil mist has been separated flows down the blow-by gas passage 31 including the pipes 17, 27, and 29, and circulates from the oil mist separator 5 to the intake system 9. Since the inside of the pipe 17 provided in the cover 15 is caused to flow down and circulate to the intake system 9, the blowby gas is kept warm by flowing through the valve cover 15 having a high temperature and is circulated to the intake system 9.

  In addition, since the pipe 17 is integrally formed with the valve cover 15 that is mounted at a high position above the cylinder head, even if the inside of the blow-by gas passage 31 cools down and moisture adheres to the inner wall after the engine 3 stops, the blow-by gas passage Moisture does not accumulate in 31, and the water is smoothly drained to the oil mist separator 5 and the intake system 9.

  Therefore, according to the present embodiment, even during operation in an extremely cold environment, the blow-by gas passage 31 is not cooled, and the moisture in the blow-by gas flowing through the inside does not freeze. Then, after the engine 3 is stopped, moisture does not accumulate in the blow-by gas passage 31.

  The valve cover 15 may be removed from the cylinder head during maintenance, but the pipe 17 is integrally formed with the valve cover 15, and the pipes 27 and 29 are detachably connected thereto. / Assembly of the blow-by gas passage 31 is easy without any hindrance to removal.

  And, compared to the conventional example of covering the blow-by gas passage with a heat insulation pipe or covering the blow-by gas passage with a heat insulation cover to prevent the blow-by gas passage from freezing, the entire blow-by gas recirculation device 33 has a small number of parts. There is an advantage that an inexpensive system with a simple structure can be obtained.

3 Engine 5 Oil Mist Separator 9 Engine Intake System 11 Engine Exhaust System 13 Cooling Fan 15 Valve Covers 17, 27, 39 Pipes 19, 21 Pipe Ends 23, 25 Side Wall 31 Blowby Gas Passage 33 Blowby Gas Recirculation Device

Claims (1)

In a blow-by gas recirculation device that arranges an oil mist separator on the side of the engine opposite to the engine intake system, separates the oil mist in the blow-by gas with the oil mist separator, and circulates the blow-by gas to the engine intake system.
A pipe that penetrates the inside of the valve cover is integrally formed on a resin valve cover that is attached to the upper part of the cylinder head of the engine, and one end side of the pipe and the engine intake system, and the other end side of the pipe and the oil mist A blow-by gas recirculation device comprising a blow-by gas passage through which a blow-by gas flows from an oil mist separator to an intake system by connecting the separator with a pipe or tube.

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