JP2007146772A - Blow-by gas ventilation system for internal combustion engines - Google Patents

Abstract

A fresh air introduction pipe for introducing clean air from an air cleaner is connected to an engine body so as to send clean air into the engine body to ventilate blow-by gas generated in a crank chamber of the engine body. In the blow-by gas ventilator, the temperature of the air fed into the crank chamber is increased to prevent oil deterioration.
A blow-by gas outlet pipe (63) for guiding blow-by gas accompanying clean air sent into the engine body (11) is connected to an air cleaner (38), and a downstream end of a fresh air introduction pipe (57) is a cylinder head (14) of the engine body (11). The engine body 11 is connected so that clean air is fed into the crank chamber 34 from the side.
[Selection] Figure 1

Description

  The present invention relates to an internal combustion engine in which a fresh air introduction pipe that guides clean air from an air cleaner is connected to the engine body so as to send clean air into the engine body to ventilate blow-by gas generated in the crank chamber of the engine body. Relates to a blow-by gas ventilator.

For example, Patent Document 1 discloses that clean air from an air cleaner is introduced into an engine main body to ventilate blow-by gas generated in the crank chamber, and blow-by gas led out from the engine main body is guided to the air cleaner. Yes.
Japanese Patent Laid-Open No. 2005-121008

  However, according to the blow-by gas ventilator disclosed in Patent Document 1, clean air from the air cleaner is fed into the crank chamber, and blow-by gas generated in the crank chamber is accompanied by the fed air. From the cylinder head and the head cover to the air cleaner, the air cleaner is configured so that air having a relatively low temperature is fed into the crank chamber. However, in order to prevent condensation of moisture and gasoline components contained in the blow-by gas in the crank chamber and to prevent oil deterioration due to the condensate being mixed into the oil, the air fed into the crank chamber is replaced with its saturated water vapor. In order to increase the amount, a higher temperature is desirable.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a blow-by gas ventilation device for an internal combustion engine that can prevent oil deterioration by increasing the temperature of the air fed into the crank chamber. To do.

  In order to achieve the above object, the invention according to claim 1 is characterized in that the fresh air introduction pipe for introducing clean air from the air cleaner has clean air in the engine body so as to ventilate blow-by gas generated in the crank chamber of the engine body. In the blow-by gas ventilating apparatus for an internal combustion engine connected to the engine body so as to feed in, the blow-by gas lead-out pipe for guiding the blow-by gas accompanying the clean air sent into the engine body is connected to the air cleaner, and the fresh air The downstream end of the introduction pipe is connected to the engine body so as to feed clean air from the cylinder head side of the engine body to the crank chamber.

  According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, the fresh air introduction pipe is connected to the air cleaner via a one-way valve that allows only the flow to the engine body side. It is characterized by that.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect of the present invention, the connection port for connecting the upstream end of the blow-by gas lead-out pipe includes a crankcase of the engine body, and left and right sides of the crankcase. It is provided in at least one of the crankcase covers coupled to the.

  According to a fourth aspect of the invention, in addition to the configuration of the first aspect of the invention, a valve operating chamber for accommodating a valve operating mechanism is formed between the cylinder head and the head cover of the engine body. In addition, a shielding plate that prevents the splashing of oil droplets from the valve operating chamber is formed so that the air confining chamber partitioned from the valve operating chamber can send air to the cylinder head side through the valve operating chamber. The fresh air introduction pipe is connected to the head cover through the air storing chamber.

  According to a fifth aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the fresh air introduction pipe is connected to an air accumulation chamber in parallel with the air cleaner. .

  Further, the invention according to claim 6 is characterized in that, in addition to the structure of the invention according to claim 5, the air accumulation chamber is formed in a vehicle body constituting member of a motorcycle.

  According to the first aspect of the present invention, since clean air from the air cleaner is sent to the crank chamber via the cylinder head, the air heated by the cylinder head and having a relatively high temperature is sent to the crank chamber. By increasing the amount of saturated water vapor in the air that is sent in, it is possible to prevent condensation of moisture and gasoline components contained in the blow-by gas in the crank chamber, and prevent oil deterioration due to the condensate being mixed into the oil. The oil life can be extended.

  According to the invention described in claim 2, since only the flow of air to the engine body side is permitted by the one-way valve, the warmed air can be efficiently fed into the crank chamber according to the breathing of the crank chamber. it can.

  According to invention of Claim 3, blowby gas can be efficiently discharged | emitted from a crank chamber.

  According to the fourth aspect of the present invention, clean air from the air cleaner can be temporarily stored in the air storage chamber and the temperature can be raised, and higher-temperature air that does not contain oil scattered from the valve mechanism is supplied to the crank chamber. Can be sent.

  According to the fifth aspect of the present invention, a relatively large amount of air can be sent from the fresh air introduction pipe to the engine body side, and the ventilation efficiency of the blow-by gas is improved by a synergistic effect by the combination with the air storage chamber. .

  Furthermore, according to the invention described in claim 6, it is possible to reduce the number of parts by forming the air accumulation chamber with the vehicle body constituent member without using a dedicated part for forming the air accumulation chamber.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 3 show a first embodiment of the present invention. FIG. 1 is a partially cutaway side view of an internal combustion engine, and FIG. 2 is an internal combustion engine with a head cover of an engine body and an air cleaner cover removed. FIG. 3 is a sectional view taken along line 3-3 of FIG.

  First, in FIG. 1, an engine body 11 of the internal combustion engine includes a crankcase 12, a cylinder block 13 coupled to the upper part of the crankcase 12, a cylinder head 14 coupled to the upper part of the cylinder block 13, and a cylinder head 14. And a piston 17 slidably fitted to a cylinder bore 16 formed in the cylinder block 13 is connected to a crankshaft 18 rotatably supported by the crankcase 12. They are connected via a rod 19.

  A combustion chamber 20 that faces the top of the piston 17 is formed between the cylinder block 13 and the cylinder head 14, and an intake port 21 and an exhaust port 22 are provided on the opposite side walls of the cylinder head 14. The cylinder head 14 includes an intake valve 23 that controls the inflow of the air-fuel mixture from the intake port 21 to the combustion chamber 20, and an exhaust valve 24 that controls the outflow of exhaust gas from the combustion chamber 20 to the exhaust port 22. Is arranged to be openable and closable.

  Referring also to FIG. 2, a valve operating chamber 31 for accommodating the valve operating mechanism 30 is formed between the cylinder head 14 and the head cover 15. The valve operating mechanism 30 includes the intake valve 23 and the exhaust valve. 24, a camshaft 25 common to the camshaft 24, an intake-side rocker arm 27 that opens and closes the intake valve 23 by swinging following an intake-side cam 26 provided on the camshaft 25, and an exhaust provided on the camshaft 25. An exhaust side rocker arm 29 that opens and closes the exhaust valve 24 by swinging following the side cam 28 is provided.

  A timing transmission mechanism 33 having a cam chain 32 between one end of the camshaft 25 and one end of the crankshaft 18 reduces the rotational power of the crankshaft 18 to 1/2 and transmits it to the camshaft 25. A passage 35 connecting the crank chamber 34 formed in the crankcase 12 through the cylinder bore 16 and the valve operating chamber 31 causes the cam chain 32 to travel and the cylinder block 13 and The crank chamber 34 is provided in the cylinder head 14 and communicates with the valve operating chamber 31 through the passage 35.

  An intake device 42 having an air cleaner 38, a connecting tube 39, a carburetor 40 and an intake pipe 41 in order from the upstream side is connected to the intake port 21 of the cylinder head 14.

  A cleaner case 43 of the air cleaner 38 includes a box-shaped case main body 44 opened upward and a cover 45 coupled to an upper portion of the case main body 44. The cleaner case 43 is disposed between the case main body 44 and the cover 45. An unpurified chamber 47 and a purified chamber 48 are formed with the sandwiched cleaner element 46 interposed therebetween, and outside air is sucked into the unpurified chamber 47 from a suction pipe 49 attached to the cover 45. The connecting tube 39 is airtightly penetrated through the case main body 44 of the cleaner case 43 so that the upstream end of the connecting tube 39 opens into the purification chamber 48, and is purified by passing through the cleaner element 46. The clean air is led from the purification chamber 48 through the connecting tube 39 to the vaporizer 40 side.

  The cylinder head 14 and the head cover 15 are provided with a secondary air passage 50 having a downstream end opened to the exhaust port 22, and a secondary air supply path from the purification chamber 48 of the air cleaner 38 to the secondary air passage 50. Secondary air is led through 51.

  The secondary air supply path 51 includes a first conduit 52 whose upstream end is connected to the case main body 44 of the cleaner case 43 so as to communicate with the purification chamber 48, and a control valve connected to the downstream end of the first conduit 52. 53, a second conduit 54 having an upstream end connected to the control valve 53, a downstream end connected to the head cover 15 so as to communicate with the secondary air passage 50, and an upstream end being a downstream end of the second conduit 54. And a third conduit 55 connected to.

  The control valve 53 is a negative pressure control type opening control valve that reduces the opening as the negative pressure in the intake pipe 41 increases, and a negative pressure extraction pipe that extracts the negative pressure of the intake pipe 41. 56 is connected to the control valve 53. The control valve 53 incorporates a reed valve that allows only flow from the first conduit 52 to the second conduit 54 side, that is, from the purification chamber 48 of the air cleaner 38 to the exhaust port 22 side.

  By the way, a part of the combustion product generated in the combustion chamber 20 leaks to the crank chamber 34 side from between the piston 17 and the cylinder bore 16 as blow-by gas, and when this blow-by gas stays in the crank chamber 34, the blow-by gas Moisture and gasoline components contained therein are condensed and mixed into the oil stored in the lower part of the crank chamber 34, causing oil deterioration. Accordingly, a fresh air introduction pipe 57 that guides clean air from the air cleaner 38 is connected to the engine body 11 to ventilate the blow-by gas generated in the crank chamber 34 of the crankcase 12 in the engine body 11. The blow-by gas generated in 34 is ventilated with clean air, and is quickly discharged without staying in the crank chamber 34.

  Incidentally, the downstream end of the fresh air introduction pipe 57 is connected to the engine body 11 so as to send clean air from the cylinder head 14 side to the crank chamber 34, but is formed between the cylinder head 14 and the head cover 15. In order to lubricate the valve operating mechanism 30 accommodated in the valve operating chamber 31, oil droplets are floating around the valve operating mechanism 30, and the oil droplets are mixed into the introduced clean air. In order to avoid this, as shown in FIG. 3, the head cover 15 is provided with a shielding plate 58 that shields from the valve operating chamber 31. Between the shielding plate 58 and the head cover 15, an entraining chamber 59 is formed so that the shielding plate 58 blocks the oil droplets from the valve operating mechanism 30 from entering the valve operating chamber 31. The fresh air introduction pipe 57 is connected to the head cover 15 of the engine body 11 so as to communicate with the air storing chamber 59. Thus, the clean air introduced from the fresh air introduction pipe 57 into the air stagnation chamber 59 is temporarily stored in the air stagnation chamber 59 and then guided from the valve operating chamber 31 to the crank chamber 34 through the passage 35. Will be.

  On the other hand, the upper end of the air conduit 60 is connected to the case main body 44 in the cleaner case 43 of the air cleaner 38 so as to communicate with the purification chamber 48, and the downstream end of the air conduit 60 is connected to the air conduit 60 from the side. It is connected to the upstream end of the fresh air introduction pipe 57 via a reed valve 61 as a one-way valve that allows only circulation. That is, the fresh air introduction pipe 57 is connected to the air cleaner 38 via the reed valve 61 and the air conduit 60, and when the pressure on the air stagnation chamber 59 side is lower than the pressure on the purification chamber 48 side of the air cleaner 38. The reed valve 61 is opened, and clean air from the purification chamber 48 is introduced into the stagnation chamber 59.

  A maze-like breather maze chamber 62 communicating with the inside of the crank chamber 34 is formed in the upper portion of the crankcase 12, and a blow-by gas outlet pipe having an upstream end connected to the upper portion of the crankcase 12 so as to communicate with the breather maze chamber 72. The downstream end of 63 is connected to the case main body 44 of the air cleaner 38 so as to communicate with the purification chamber 48.

  Next, the operation of the first embodiment will be described. The fresh air introduction pipe 57 that guides clean air from the air cleaner 38 supplies clean air into the engine body 11 to ventilate the blow-by gas generated in the crank chamber 34. According to the present invention, the downstream end of the fresh air introduction pipe 57 sends clean air from the cylinder head 14 side to the crank chamber 34 in accordance with the present invention. The blow-by gas outlet pipe 63 that guides the blow-by gas accompanying the clean air sent into the engine body 11 is connected to the air cleaner 38.

  Accordingly, since clean air from the air cleaner 38 is sent to the crank chamber 34 via the cylinder head 14, the air heated by the cylinder head 14 and having a relatively high temperature is sent to the crank chamber 34. By increasing the amount of saturated water vapor in the air generated, it is possible to prevent condensation of moisture and gasoline components contained in the blow-by gas in the crank chamber 34, and to prevent oil deterioration due to contamination of the condensate into the oil. Life can be extended.

  The fresh air introduction pipe 57 is connected to the air cleaner 38 via a reed valve 61 that allows only the flow to the engine body 11 side. The reed valve 61 allows only the flow of air to the engine body 11 side. Since it is allowed, warmed air can be efficiently fed into the crank chamber 34 in accordance with the breathing of the crank chamber 34.

  Further, a valve operating chamber 31 for accommodating the valve operating mechanism 30 is formed between the cylinder head 14 and the head cover 15, and a valve operating chamber 31 is provided by a shielding plate 58 that prevents the splashing of oil from the valve operating chamber 31. Is formed so that the partitioned air stagnation chamber 59 can send air to the cylinder head 14 side through the valve operating chamber 31, and the fresh air introduction pipe 57 is connected to the air stagnation chamber 59 to the head cover 15. Since it is connected, clean air from the air cleaner 38 can be temporarily stored in the air storage chamber 59 to raise the temperature, and higher temperature air that does not contain oil scattered from the valve mechanism 30 is sent to the crank chamber 34. be able to.

  FIG. 4 shows a second embodiment of the present invention. Crankcase covers 65 and 66 are coupled to the left and right sides of the crankcase 12 in the engine body 11, and a connection port 67 provided in the crankcase 12 is connected. The upstream ends of the blow-by gas outlet pipes 70, 71, 72 are connected to at least one of the crankcase covers 65, 66, and the connection ports 68, 69 provided in both in this embodiment. The downstream ends of the pipes 70 to 72 are connected in common to a collective outlet pipe 73 connected to the air cleaner 38.

  According to the second embodiment, blowby gas can be efficiently discharged from the crank chamber 34 of the crankcase 12 (see the first embodiment).

  FIG. 5 shows a third embodiment of the present invention. The parts corresponding to the first embodiment are indicated by the same reference numerals, and the detailed description is omitted.

  The fresh air introduction pipe 57 connected to the head cover 15 of the engine body 11 is connected to the air cleaner 38 via the reed valve 61 and connected to the air accumulation chamber 75 in parallel with the air cleaner 38.

  That is, the reed valve 61 is connected to the air cleaner 38 via the downstream air conduit 76, the T-shaped joint 77, and the upstream air conduit 78. The reed valve 61 includes a branch pipe 79 having one end connected to the joint 77. The other end is connected to the chamber forming member 74 so as to communicate with an air accumulation chamber 75 formed in the chamber forming member 74.

  According to the third embodiment, when the reed valve 61 is opened, a relatively large amount of air can be sent from the fresh air introduction pipe 57 to the engine body 11 side using the inertia force of air. The ventilation efficiency of blow-by gas is improved by a synergistic effect by the combination with the enclosing chamber 59 (see the first embodiment).

  As still another embodiment of the present invention, the chamber forming member 74 forming the air accumulation chamber 75 of the third embodiment may be a vehicle body constituting member of a motorcycle, for example, a frame member such as a main frame or a rear frame. In this case, it is possible to reduce the number of parts by eliminating the need for dedicated parts for forming the air accumulation chamber 75.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

It is a partially cutaway side view of the internal combustion engine of the first embodiment. FIG. 3 is a plan view of the internal combustion engine in a state in which a head cover of the engine body and an air cleaner cover are removed. FIG. 3 is a sectional view taken along line 3-3 in FIG. 1. It is a top view which shows the principal part of the internal combustion engine of 2nd Example. It is a top view corresponding to FIG. 2 of 3rd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Engine main body 14 ... Cylinder head 15 ... Head cover 30 ... Valve operating mechanism 31 ... Valve operating chamber 34 ... Crank chamber 38 ... Air cleaner 57 ... Fresh air introduction pipe 58 ... Shield plate 59 ... Air trapping chamber 61 ... Reed valves 63, 70, 71, 72 as one-way valves ... Blow-by gas outlet pipes 65, 66 ... Crankcase cover 67, 68, 69 ... connection port 75 ... air storage chamber

Claims (6)

  The fresh air introduction pipe (57) for guiding clean air from the air cleaner (38) cleans the air in the engine body (11) so as to ventilate the blow-by gas generated in the crank chamber (34) of the engine body (11). In the blow-by gas ventilator for an internal combustion engine connected to the engine body (11) in such a manner as to feed in, the blow-by gas lead-out pipes (63, 70) for guiding the blow-by gas accompanying clean air fed into the engine body (11). , 71, 72) are connected to the air cleaner (38), and the downstream end of the fresh air introduction pipe (57) is cleaned from the cylinder head (14) side of the engine body (11) to the crank chamber (34). A blow-by gas ventilation device for an internal combustion engine, wherein the blow-by gas ventilation device is connected to the engine body (11) so as to send fresh air.   The fresh air introduction pipe (57) is connected to the air cleaner (38) through a one-way valve (61) that allows only the flow to the engine body (11). A blow-by gas ventilation device for an internal combustion engine as described.   Connection ports (67, 68, 69) for connecting the upstream ends of the blow-by gas outlet pipes (70 to 72) are connected to the crankcase (12) of the engine body (11) and to the left and right of the crankcase (12). The blow-by gas ventilation device for an internal combustion engine according to claim 1 or 2, wherein the blow-by gas ventilation device is provided on at least one of the crankcase covers (65, 66) to be joined.   A valve operating chamber (31) for accommodating the valve operating mechanism (30) is formed between the cylinder head (14) and the head cover (15) of the engine body (11). An air stagnation chamber (59) that is partitioned from the valve operating chamber (31) by a shielding plate (58) that prevents the splashing of oil droplets passes air to the cylinder head (14) through the valve operating chamber (31). The fresh air introduction pipe (57) is formed so as to be able to be fed, and is connected to the head cover (15) through the air storing chamber (59). A blow-by gas ventilation device for an internal combustion engine according to claim 1.   The blow-by gas ventilation of the internal combustion engine according to any one of claims 1 to 4, wherein the fresh air introduction pipe (57) is connected to an air accumulation chamber (75) in parallel with the air cleaner (38). apparatus.   The blow-by gas ventilation device for an internal combustion engine according to claim 5, wherein the air accumulation chamber (75) is formed in a vehicle body component of a motorcycle.

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