JP5258588B2 - Exhaust secondary air passage structure - Google Patents

Description

  The present invention relates to an exhaust secondary air passage structure for supplying secondary air introduced from a pump to an exhaust port provided in a cylinder head having an in-line cylinder row.

  Patent Document 1 discloses a structure for supplying secondary air from a control valve to each exhaust port of a plurality of cylinder heads in order to increase the exhaust gas purification efficiency of the engine. In Patent Document 1, an exhaust secondary air passage is disposed in the vicinity of the exhaust port and is heated by exhaust heat. Since the catalyst for purifying the exhaust is more activated at a high temperature, it is preferable to heat the secondary air with the heat in the vicinity of the exhaust port as in Patent Document 1.

JP-A-5-86851

  A passage for sending secondary air from a control valve (hereinafter also referred to as a secondary air valve) to the exhaust port is provided in the vicinity of the exhaust port in order to simplify the structure. It is conceivable to shorten the length. However, if the passage is shortened, there is a concern that the secondary air valve receives heat from the exhaust port and affects the product life. Therefore, if the secondary air valve is provided away from the engine, the secondary air valve will not be affected by the heat, but the passage extending from the secondary air valve becomes long and is not heated by the heat of the exhaust port. There is concern that the secondary air is not heated and the activation of the catalyst is stagnant.

  The present invention has been made in view of such problems, and an object of the present invention is to provide an exhaust secondary air passage structure that reduces as much as possible the heat received by the secondary air valve from the exhaust port.

An exhaust secondary air passage structure according to the present invention is an exhaust secondary air passage structure that supplies secondary air introduced from a pump to an exhaust port provided in a cylinder head of an engine having an in-line cylinder row. Te, a secondary air valve disposed in the timing train chamber side of and the cylinder head provided in the intake port side surface of the cylinder head, from the secondary air valve, is provided in the timing train chamber side surface of the cylinder head , and the side passage extending toward the exhaust port side from the lateral passage, the inter-cylinder passage provided in the exhaust port side or near the side surface of the cylinder head along the cylinder row direction, the provided in the cylinder head, the exhaust ports and the inter-cylinder passage have a branch passage communicating respectively Bal of the secondary air valve And said lateral passage and the discharge port is characterized in that it engagement.

  Since the side passage is provided on the timing train chamber side, it is difficult to be heated, and since the secondary air valve is provided on the intake port side, the secondary air valve receives heat from the exhaust port as much as possible. This reduces the deterioration of the product due to heat. Further, the activation of the catalyst can be maintained by heating the secondary air in the inter-cylinder passage and the branch passage with heat from the exhaust port. The timing train may be any system such as a timing chain, a timing belt, or a timing gear.

Further, the engine is a V-type engine, and the exhaust secondary air passage structure is provided in two sets, and the two secondary air valves do not protrude upward and laterally of the V shape of the engine. It is arrange | positioned inside the inside.

  Thus, the secondary air valve does not protrude above and to the side of the engine, which is preferable in terms of layout.

  According to the exhaust secondary air passage structure according to the present invention, the secondary air valve provided in the vicinity of the intake port is provided apart from the exhaust port, so that the heat received from the exhaust port is as much as possible. By reducing the product, the deterioration of the product of the secondary air valve due to the heat is suppressed, but the secondary air is heated by the heat from the exhaust port in the inter-cylinder passage and the branch passage, thereby activating the catalyst. The effect of maintaining can be achieved.

1 is an overall perspective view showing an engine having an exhaust secondary air passage structure according to the present embodiment. It is a partially omitted perspective view showing a chain case side of an engine having an exhaust secondary air passage structure according to the present embodiment. It is a schematic plan view of a cylinder head having an exhaust secondary air passage structure according to the present embodiment. FIG. 6 is a partially omitted perspective view of the side of the cylinder head on the side of the timing train chamber.

  Hereinafter, an exhaust secondary air passage structure according to the present invention will be described with reference to FIGS.

  First, a schematic configuration of the engine 10 to which the exhaust secondary air passage structure 50 according to the present embodiment is applied will be described.

  As shown in FIGS. 1 and 2, the engine 10 is a V-type 10-cylinder engine for a vehicle in which the first cylinder row 12a and the second cylinder row 12b form a 90 ° bank. The engine 10 is configured such that a base portion is stacked from the lower side in order of a lower oil pan 14, an upper oil pan 16, a cylinder block 18, a cylinder head 20, and a head cover 22. One cylinder head 20 and one head cover 22 are provided for each of the first cylinder row 12a and the second cylinder row 12b. An annular rib 24 to which a transmission is attached is formed on one side of the engine 10. A level gauge 26 is provided on the head cover 22 in the second cylinder row 12b.

  The lower oil pan 14 stores lubricating oil. The upper oil pan 16 is a portion constituting the crankcase by connecting the lower oil pan 14 and the cylinder block 18, and a space for rotating the counterweight is secured. The cylinder block 18 is a Y-shaped part as viewed from the side, which forms the main part of the first cylinder row 12a and the second cylinder row 12b, and forms five cylinders per bank. The cylinder is configured such that the piston moves up and down, and the crankshaft 28 is rotated via the connecting rod. Each piston rotates at a different phase to cancel out the vibrations.

As shown in FIGS. 1 and 3, the cylinder head 20 is a part that covers the upper part of the cylinder to form a combustion chamber, and is provided with a valve that opens and closes the combustion chamber, a valve operating mechanism thereof, an ignition plug, and the like. The cylinder head 20 is formed with an intake port 42 and an exhaust port 44 communicating with the combustion chamber of each cylinder, and each intake port 42 is formed in a V shape formed by the first cylinder row 12a and the second cylinder row 12b. An intake manifold 30 is formed on the inner side, and each exhaust port 44 forms an exhaust manifold 32 on the outer side of the V shape. A plurality of oil dropping holes 46 are spaced apart from each other at the bottom of the end of the cylinder head 20 on the exhaust port 44 side, and are drilled in the axial direction of the cylinder. The cylinder block 18 and the upper oil pan 16 By communicating with the lower oil pan 14 in order, it has a function as a passage for collecting the lubricating oil.

  The intake manifold 30 is connected to an intake pipe and a fuel injector (not shown). The exhaust manifold 32 is connected to five exhaust pipes 34 each having a leading end portion for each of the first cylinder row 12a and the second cylinder row 12b. Each of the five exhaust pipes 34 has an appropriate length, is bent so as to be compactly gathered at the lower part of the first cylinder row 12a and the second cylinder row 12b, and gathers in the gathering portion 34a. . The two collecting portions 34a are directed in the same direction in the first cylinder row 12a and the second cylinder row 12b, respectively, and are connected to a muffler and a catalyst (not shown).

  As shown in FIG. 2, one side of the engine 10 is covered with a chain case (or timing train case) 38, and a timing train chamber 36 is formed between the cylinder block 18 and the cylinder head 20. ing. Since the timing train chamber 36 is provided apart from the combustion chamber, the timing train chamber 36 is at a lower temperature than each cylinder row, that is, the cylinder head 20. The timing train chamber 36 is provided with a timing train mechanism that transmits the rotation of the crankshaft 28 to the valve operating mechanism by power transmission means such as a timing chain, a timing belt, or a timing gear. The timing train chamber 36 has a side surface covered with a chain case 38 and an upper surface covered with a head cover 22. The timing train chamber 36 communicates with the lower oil pan 14. An oil supply port 40 is provided on one side of the engine 10.

  Next, the exhaust secondary air passage structure 50 according to the present embodiment will be described.

  The exhaust secondary air passage structure 50 refers to an exhaust port 44 provided in the cylinder head 20 having an in-line cylinder row by introducing secondary air from the outside using a pump and supplying it to the catalyst. This is a structure for increasing the gas purification efficiency.

  As shown in FIG. 3, the exhaust secondary air passage structure 50 includes a secondary air valve 52, a side passage 54, an inter-cylinder passage 56, and a branch passage 58. The exhaust secondary air passage structure 50 is provided as one symmetrical structure with respect to each of the first cylinder row 12a and the second cylinder row 12b. However, the exhaust secondary air passage structure 50 is provided with respect to the first cylinder row 12a. With the description of the secondary air passage structure 50, the description of the exhaust secondary air passage structure 50 provided for the second cylinder row 12b is omitted.

  The secondary air valve 52 is connected to the air valve main body 60, a valve air inlet 62 that connects a secondary air pump (not shown) provided in a vehicle body frame near the engine 10 via a tube, and the side passage 54. And a valve outlet 64 which is joined. The secondary air valve 52 is disposed on the inner side of the V-shape formed by the first cylinder row 12a and the second cylinder row 12b on the timing train chamber 36 side of the cylinder head 20, and protrudes upward and laterally. Therefore, it is preferable in terms of layout.

  The secondary air valve 52 is disposed on the side surface of the cylinder head 20 on the side of the intake port 42 that is the inside of the V-shape, that is, at the corner of the cylinder head 20, so that the exhaust port heated by the combustion chamber passes through. The influence of heat received from 44 can be reduced as much as possible. As a result, the secondary air valve 52 can suppress deterioration of the product due to heat. Furthermore, since the secondary air valve 52 is provided on the timing train chamber 36 side, which is at a lower temperature than each cylinder row, it is possible to suppress deterioration of the product due to heat. The secondary air valve 52 is turned on when the exhaust gas contains a large amount of unburned gas containing a lot of harmful components, and burns the harmful components of the unburned gas to promote harmlessness. On the other hand, when the exhaust efficiency of a muffler (not shown) is excessive, the amount of the unburned gas increases, and a phenomenon called afterburning in which the unburned gas is burned in the muffler occurs, and noise generation factors Therefore, in such a case, the secondary air valve 52 is turned off.

  The air valve main body 60 has a function as a valve and has a function of adjusting the flow rate of the secondary air discharged from the valve discharge port 64 to the side passage 54 with respect to the secondary air flowing in from the valve intake port 62. . The secondary air is not only compressed by a secondary air pump (not shown), but also the secondary air flows into the air valve main body 60 due to a suction phenomenon caused by the flow of exhaust from the exhaust port 44.

  The side passage 54 extends from the intake port 42 side to the exhaust port 44 side on the side upper side of the cylinder head 20 on the timing train chamber 36 side, that is, the arrangement direction of the first cylinder row 12a (arrow A in FIGS. 1 and 3). And a passage drilled in a direction perpendicular to the axial direction of the cylinder, and is formed by drilling from the intake port 42 side of the cylinder head 20 to the vicinity of the end portion on the exhaust port 44 side without penetrating.

  As shown in FIG. 4, the side passage 54 is integrated with the side wall 66 of the cylinder head 20 on the timing train chamber 36 side, and is formed in a cylindrical shape having an inner diameter of 0.5 cm to 5.0 cm. By being provided so that the center is located on the surface of the side wall 66, the side passage 54 protrudes sideways in an arc shape from the side wall 66 to form a convex portion 68.

  By forming the convex portion 68, the side wall 66 of the cylinder head 20 on the timing train chamber 36 side is further increased in thickness. As a result, while the rigidity of the cylinder head 20 is improved, the height of the side wall 66 is not changed, so that the atomized lubricating oil and air are mixed between the cylinder head 20 and the timing train chamber 36. It does not obstruct the flow of blow-by gas. On the other hand, the thickness of the side wall 66 is increased, and the cylinder head 20 and the timing train chamber 36 are further separated from each other. A structure for filtering the oil can be obtained without obstructing the flow of blow-by gas. Further, since the oil component is filtered from the blow-by gas, it is possible to suppress the oil from being stirred and scattered by driving the timing chain or the timing gear in the timing train chamber 36. Further, when a timing belt is used as the timing train mechanism, the inflow of the oil is prevented and deterioration of the timing belt is suppressed. As a result, the oil is easily condensed and liquefied, and the liquefied oil is accumulated at the bottom of the cylinder head 20. Therefore, the oil for lubrication can be easily collected by the oil dropping hole 46 provided at the bottom of the cylinder head 20.

  The blow-by gas is heated by the exhaust port 44 of the cylinder head 20, but the blow-by gas moves from the cylinder head 20 toward the timing train chamber 36 and comes into contact with the side passage 54 so that the side passage 54 has a certain degree. As a result, the secondary air flowing through the side passage 54 is also heated, and the catalyst can be activated. However, the heating by the blow-by gas cannot be heated to the extent that the deterioration of the secondary air valve 52 is affected. Further, the side passage 54 is formed integrally with the side wall 66 so that the timing train chamber 36 is interposed between the side passage 54 and the chain case 38. Therefore, even if high-temperature gas flows backward from the exhaust port 44 into the exhaust secondary air passage structure 50, the influence of the chain case 38 due to heat can be reduced as much as possible.

  The inter-cylinder passage 56 is a passage that penetrates the upper end of the cylinder head 20 on the exhaust port 44 side, is formed in parallel with the arrangement direction of the first cylinder row 12a, and is sealed at both ends by bolts 48. . The inter-cylinder passage 56 has a cylindrical shape having the same diameter as that of the side passage 54, and communicates orthogonally at the end of the side passage 54 on the exhaust port 44 side of the cylinder head 20. Under the influence of the heat from the exhaust gas heated in the combustion chamber, the secondary air flowing through the inter-cylinder passage 56 is also heated at the same time to activate the catalyst by being heated in the inter-cylinder passage 56. it can. The inter-cylinder passage 56 is not necessarily provided at the end of the cylinder head 20 on the exhaust port 44 side, and may be in the vicinity of the end.

  Further, both the side passage 54 and the inter-cylinder passage 56 are formed integrally with the cylinder head 20 and are separated from the joint portion between the cylinder head 20 and the head cover 22, and the thermal influence on the joint portion is exerted. It can be reduced as much as possible. Although the sealing function of the head cover 22 with respect to the cylinder head 20 is deteriorated by heat, the deterioration of the sealing function can be suppressed by reducing the influence of the joint portion to the heat as much as possible.

  The branch passage 58 is a passage provided corresponding to each cylinder of the first cylinder row 12a (in this case, five) and communicating with the inter-cylinder passage 56. The branch passage 58 has a smaller diameter than the side passage 54 and the inter-cylinder passage 56, and communicates the exhaust port 44 and the inter-cylinder passage 56, respectively. As a result, the secondary air is discharged to the exhaust port 44, mixed with the exhaust gas, and sent to a catalyst (not shown). Also in the branch passage 58, the secondary air is heated similarly to the inter-cylinder passage 56, so that the catalyst can be activated.

  As described above, according to the exhaust secondary air passage structure 50 according to the present embodiment, the secondary air valve 52 suppresses product deterioration due to heat by reducing the heat received from the exhaust port 44 as much as possible. However, the secondary air is heated by the heat from the exhaust port 44 in the side passage 54, the inter-cylinder passage 56, and the branch passage 58, thereby achieving the effect of maintaining the activation of the catalyst. it can.

  The exhaust secondary air passage structure according to the present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Engine 12a ... 1st cylinder row 12b ... 2nd cylinder row 14 ... Lower oil pan 16 ... Upper oil pan 18 ... Cylinder block 20 ... Cylinder head 22 ... Head cover 24 ... Annular rib 26 ... Level gauge 28 ... Crankshaft 30 ... Intake manifold 32 ... Exhaust manifold 34 ... Exhaust pipe 34a ... Collecting portion 36 ... Timing train chamber 38 ... Chain case 40 ... Supply port 42 ... Inlet port 44 ... Exhaust port 46 ... Oil drop hole 48 ... Bolt 50 ... Exhaust secondary air passage Structure 52 ... Secondary air valve 54 ... Side passage 56 ... Inter-cylinder passage 58 ... Branch passage 60 ... Air valve body 62 ... Valve intake port 64 ... Valve discharge port 66 ... Side wall 68 ... Projection

Claims (2)

An exhaust secondary air passage structure for supplying secondary air introduced from a pump to an exhaust port provided in a cylinder head of an engine having an in-line cylinder row,
A secondary air valve provided on the side of the intake port of the cylinder head and disposed on the timing train chamber side of the cylinder head ;
From the secondary air valve, it is provided in the timing train chamber side surface of the cylinder head, and the side passage extending toward the exhaust port side,
An inter-cylinder passage provided on the exhaust port side surface of the cylinder head or in the vicinity thereof along the cylinder row direction from the side passage;
A branch passage provided in the cylinder head and communicating with the inter-cylinder passage and the exhaust port;
I have a,
An exhaust secondary air passage structure , wherein a valve discharge port of the secondary air valve and the side passage are joined . The exhaust secondary air passage structure according to claim 1,
The engine is a V-type engine,
Two sets of the exhaust secondary air passage structure are provided,
The two secondary air valves are disposed on the V-shaped upper side of the engine and on the inner side of the V-shaped so as not to protrude sideways .

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