Title of Invention

SECONDARY AIR SUPPLY SYSTEM FOR PURIFYING EXHAUST EMISSION FROM ENGINE

Abstract To provide a rationally configured secondary air supply system for purifying exhaust emission from engine in which the valve means does not increase the length of the engine in the direction of the axis of the cylider and resists endamagement by heat form the cylinder head. A head cover 35 is joined to the cylinder head 34 for defining a motion valve chamber 36 therebetween, a valve housing 74 is provided continuously on one side of the head cover 35 so as to lie next to, but not to come into contact with, the outer surface of the cylinder head 34, and the valve means 75 for supplying secondary air for purifying exhaust gas to the exhaust port 27e is accomodated in the valve housing 74.
Full Text FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
COMPLETE SPECIFICATION
[See Section 10]
"SECONDARY AIR SUPPLY SYSTEM FOR PURIFYING EXHAUST EMISSION FROM ENGINE"
HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, having a place of business at 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan,
The following specification particularly describes the nature of the invention and the manner in which it is to be performed:-

[Detailed Description of the Invention]
[0001] [Technical Field to which the Invention Belongs]
The present invention relates to an improvement of a cylinder head apparatus for engines comprising a cylinder head, a head cover joined to the cylinder head for defining a motion valve chamber for accommodating a motion valve mechanism therebetween, and valve means provided on the head cover for supplying secondary air for purifying exhaust gas to the exhaust port formed on the cylinder head. [0002] [Description of the Related Art]
Secondary air supply system for purifying exhaust emission from engine as described above is already known as


disclosed for example in Japanese Patent Laid-Open No.203483/2000.
[0003] [Problems to be Solved by the Invention]
In secondary air supply system for purifying exhaust emission from engine in the related art, the valve means is mounted on the top wall of the head cover. Therefore, the valve means is located sufficiently away from the cylinder head and thus can advantageously resist endamagement by heat from the cylinder head, but the length of the engine increases comparatively in the direction of the axis of the cylinder, which may be disadvantageous for in-vehicle layout and the like of the engine.
[0004]
With such circumstances in view, it is an object of the present invention to provide a rationally configured secondary air supply system for purifying exhaust emission from engine in which the valve means does not increase the length of the engine in the direction of the axis of the cylinder and resists endamagement by heat from the cylinder head.
[0005] [Means for Solving the Problems]
In order to achieve the object described above, the first characteristic of the present invention is a secondary air supply system for purifying exhaust emission from engine


wherein a head cover joined to a cylinder head for defining a motion valve chamber for accommodating a motion valve mechanism therebetween, and valve means is provided on the head cover for supplying secondary air for purifying exhaust gas to a exhaust port formed on the cylinder head, characterized in that a valve housing is provided continuously on one side of the head cover so as to lie next to, but not to come into contact with, the outer surface of the cylinder head, and the valve means is accommodated in the valve housing.
[0006]
The valve means corresponds to a one-way valve 75 in the embodiment of the present invention described later.
[0007]
According to the first characteristic, the valve housing provided continuously from the head cover and disposed next to the outer wall of the cylinder head does not increase the length of the engine along the direction of the axis of the cylinder, and thus the possibility of in-vehicle layout of the engine may be expanded. In addition, since the valve housing is not in contact with the outer wall of the cylinder head, high heat of the cylinder head is hardly transmitted to the valve housing, and thus the valve means in the valve housing is prevented from being endamaged by heat from the cylinder head, thereby ensuring the durability of the valve means.
[0008]


In addition to the first characteristic, the second characteristic of the present invention is that the engine is disposed in such a manner that the axial line of the cylinder lies generally horizontally and the exhaust port is faced downward from the combustion chamber, the valve housing is provided continuously from the lower portion of the head cover that is to be joined to the cylinder head of the engine, and a breather chamber connecting between a inlet that is in communication with the motion valve chamber and a outlet disposed at the higher level than the inlet and led to the outside with a maze of passages for separating lubricant oil mist from a blow-by gas introduced from the motion valve chamber is provided between the upper portion of the head cover and the cylinder head.
[0009]
According to the second characteristic, the valve housing is positioned relatively near the exhaust port, and consequently, secondary air passage may be shortened, and thus the flow path resistance is decreased, thereby ensuring supply of secondary air to the exhaust port and contributing to improve the effectiveness of purification of exhaust gas.
[0010]
In addition to the first and second characteristic, the third characteristic of the invention is that the valve housing is disposed on the side of the cylinder head on which the ignition


plug is to be mounted-
[0011]
According to the third characteristic of the invention, the dead space around the ignition plug can be utilized for disposing a valve housing, whereby upsizing of the engine can be prevented.


[Brief Description of the Drawings] [Fig. 1]
Fig. 1 is a general side view of a scooter type motorcycle showing the first embodiment of the present invention. [Fig. 2]
Fig. 2 is a cross sectional view taken along the line 2-2 of Fig. 1. [Fig. 3J
Fig. 3 is an enlarged view of a principal portion of Fig. 2.

[0012] [Mode for Carrying Out the Invention]
An embodiment of the present invention will be further illustrated referring to an example shown in the attached drawings.
[0014]
Referring now to Fig. 1 and Fig. 2, a general construction of the scooter type motorcycle will be described.
[0015]
The vehicle body frame F of the scooter type motorcycle V provided with a front wheel Wf steered by the steering handle


11 and a rear wheel Wr driven by a swing-type power unit P is divided into three; a front frame 12, a center frame 13, and a rear frame 14. The front frame 12 is constructed of a molded body of aluminum alloy integrally comprising a head pipe 12a, a down tube 12b, and a step floor 12c. The center frame 13 for supporting the power unit P via a pivot shaft 15 so as to swing vertically is also constructed of a molded body of aluminum alloy, and connected to the rear end of the front frame 12. The rear frame 14 extending toward the upper rear of the power unit P is formed of an annular pipe member, and a fuel tank 16 is surrounded and supported by the rear frame 14. A helmet case 17 is supported on the upper surface of the center frame 13, and the helmet case 17 is covered by the lid 19 integrally including a seat 18 so as to be capable of freely opening and closing.
[0016]
The power unit P comprises a water-cooled single cylinder 4-cycle engine E, and a belt-type stepless speed change gear T extending from the left side surface of the engine E toward the rear of the vehicle body, and the upper surface of the rear portion of the stepless speed change gear T is connected to the rear end of the center frame 13 via a rear cushion 20. An air cleaner 21 is supported on the upper surface of the stepless speed change gear T, and a muffler 22 is supported on the right side surface of the stepless speed change gear T. A main stand


23 that can be stood upright and folded back is supported on the lower surface of the engine E.
[0017]
Referring now to Fig. 2, the general construction of the power unit P will be described.
[0018]
The engine body 25 of the engine E is provided with an engine block 32 divided by the parting surface extending vertically along the axis of crank shaft 31, and a rear half of crankcase 33b. The engine block 32 integrally comprises a cylinder block 32a having a cylinder bore 41 and a front half of crankcase 33a that constitutes the crankcase 33 with the rear half of crankcase 33b. A cylinder head 34 is connected to the front end of the engine block 32, and a head cover 35 is connected to the front end of the cylinder head 34.
[0019]
The engine body 25 constructed as described above is mounted on the vehicle body frame F with the axis of the cylinder L (See Fig. 1) laid generally horizontally, or more preferably, with the front side faced slightly upward as shown in the figure, so as to extend along the fore and aft direction of the vehicle body frame F.
[0020]
The belt-type stepless speed change gear T comprises a right casing 37 and a left casing 38 to be connected with respect


to each other. The right side surface of the front portion of the right casing 37 is connected to the left side surfaces of the front and rear halves of crankcase 32, 33. Then a speed reducer casing 39 is connected to the right side surface of the rear portion of the right casing 37.
[0021]
A drive pulley 54 is provided at the left end of the crankshaft 31 projecting into the right casing 37 and the left casing 38. The drive pulley 54 comprises a fixed half of pulley 55 fixed to the crankshaft 31 and a movable half of pulley 56 that is capable of moving toward and away from the fixed half of pulley 55, and the movable half of pulley 56 is urged toward the fixed half of pulley 55 by the centrifugal weight57 that moves radially outwardly with increase in the number of revolution of the crankshaft 31.
[0022]
A driven pulley 59 provided on the output shaft 58 supported between the rear portion of the right casing 37 and the speed reducer casing 39 comprises a fixed half of pulley 60 supported on the output shaft 58 so as to be capable of relative rotation, and a movable half of pulley 61 that is movable toward and away from the fixed half of pulley 60. The movable half of pulley 61 is urged toward the fixed half of pulley 60 by a spring 62. A starting clutch 63 is provided between the fixed half of pulley 60 and the output shaft 58. Then an


endless V-belt 64 is routed between the drive pulley 54 and the driven pulley 59.
[0023]
A intermediate shaft 65 and an axle 66 being in parallel with the output shaft 58 are supported between the right casing 37 and the speed reducer casing 39, and a speed reducing gear train 67 is provided among the output shaft 58, the intermediate shaft 65, and the axle 66. Then the rear wheel Wr is mounted on the right end of the axle 66 projecting rightward through the speed reducer casing 39 by spline fitting.
[0024]
Therefore, the rotating power of the crankshaft 31 is transmitted to the drive pulley 54, and then from the drive pulley 54 through the V-belt 64, the driven pulley 59, the starting clutch 63, and the speed reducing gear train 67 to the rear wheel Wr.
[0025]
When the engine E is rotated at a low speed, a centrifugal force acting on the centrifugal weight 57 of the drive pulley 54 is small, and thus the width of the groove between the fixed half of pulley 60 and the movable half of pulley 61 is reduced by the spring 62 of the driven pulley 59, and the gear change ratio is LOW. When the number of revolution of the crankshaft 31 increases from this state, a centrifugal force acting on the centrifugal weight 57 increases and the width of the groove


between the fixed half of pulley 55 and the movable half of pulley 56 of the drive pulley 54 decreases, and the width of the groove between the fixed half of pulley 60 and the movable half of pulley 61 of the driven pulley 59 increases accordingly. Therefore, the gear change ratio changes steplessly from LOW toward TOP.
[0026]
Referring to Fig. 2 to Fig. 4, the construction of the engine E will be described in detail.
[0027]
The piston 42 that is slidably fitted into the cylinder bore 41 provided on the engine block 32 is connected to the crankshaft 31 via a con"rod 43. The cylinder head 34 is formed with a combustion chamber 26 toward which the top surface of the piston 42 faces, and an intake and exhaust ports 27i, 27e in communication with the combustion chamber 26 respectively. The intake port 27i extends upward from the combustion chamber 26 and then bent in the shape of a letter U toward the rear, opens toward the back surface of the upper portion of the cylinder head 34, to which the carburetor 24 inhaling from the air cleaner 21 (See Fig. 1) is connected. The outer end of the exhaust port 27e extends downward from the combustion chamber 26 and opens toward the lower surface of the cylinder head 34, to which the muffler (See Fig. 1) is connected via an exhaust pipe 29. The exhaust pipe 29 or the muffler 22 is provided with a catalytic converter 30 for purifying exhaust emission.

[0028]
The cylinder head 34 is mounted with the intake and exhaust valves 28i, 28e for opening and closing the intake and exhaust ports 27i, 27e in the positions opening toward the valve head in the shape of a letter V, and an ignition plug 48 to which the electrode is to be faced is screwed at the central portion of the combustion chamber 26.
[0029]
A head cover 35 is joined on the end surface of the cylinder head 34, and a motion valve mechanism Vm for driving the intake and exhaust valves 28i, 28e to open and close is accommodated in the motion valve chamber 36 defined between the cylinder head 34 and the head cover 35. The motion valve mechanism Vm is constructed of a camshaft 44 rotatably supported by the cylinder head 34 and disposed between the intake and exhaust valves 28i, 28e, intake and exhaust locker arms 49i, 49e supported by the cylinder head 34 respectively for swinging motion and linking between the camshaft 44 and the intake and exhaust valves 28i, 28e respectively, and valve springs 50i, 50e for urging the intake and exhaust valves 28i, 28e respectively to the closing direction.
[0030]
As shown in Fig. 2 and Fig. 3, a timing chamber 40 connecting the inside of the crankcase 33 and the motion valve chamber 36 is formed along the side walls of the crankcase 33,

the cylinder block 32a, and the cylinder head 34 on one side, and the chamber 40 accommodates an endless timing chain 45 routed around a drive sprocket 46 mounted on the crankshaft 31 and a driven sprocket 47 mounted on the camshaft 44. The drive sprocket 46, the driven sprocket 47, and the timing chain 45 constitute a timing transmission unit Ti for reducing the rotating speed of the crankshaft 31 by half and transmitting it to the camshaft 44.
[0031]
Referring now to Fig. 3 to Fig. 5, secondary air supply system for purifying exhaust emission will be described.
[0032]
The head cover 35 is provided with a valve housing 74 connected at the lower portion thereof, and a one-way valve 75 is stored therein. The valve housing 74 is integrally formed at the lower portion of the head cover 35, and comprises a inner half of housing 74a lying next to, but without coming into contact with, the side wall of the cylinder head 34 on the side where the ignition plug 48 is mounted, and an outer half of housing 74b to be joined with outer surface of the inner half of housing 74a, which is in parallel with the side wall with a bolt 76.
[0033]
The one-way valve 75 having a valve hole 78a is interposed between both housing halves 74a, 74b described above, and


comprises a valve seat 78 dividing the interior of the valve housing 74 into an inner chamber 79a on the side of the inner half of housing 74a and an outer chamber 79b on the side of the outer half of housing 74b, a resilient valve plate 80 provided so as to open and close the valve hole 78a on the inner chamber 79a side, and a valve plate stopper 88 fixed on the valve seat 78 together with one end of the valve plate 80 with a screw 87 for limiting the open limit of the valve plate 80, so that the resilient valve plate 80 opens and closes according to the difference in air pressure between the inner and the outer chambers 79a, 79b.
[0034]
The outer half of housing 74b is formed integrally with a connecting tube 89 in communication with the outer chamber 79b, to which the air cleaner 21 is connected via the air duct 90. The inner chamber 79a is connected to the exhaust port 27e via secondary air passage 91 formed from the head cover 35 to the cylinder head 34.
[0035]
Therefore, while the engine E is in operation, when pulsating waves of the exhaust pressure are generated in the exhaust system including the exhaust port 27e along with the intermittent exhausting action from the combustion chamber 26 to the exhaust port 27e by the opening and closing operation of the exhaust valve 28e, and the negative pressure component

of the pulsating waves is transmitted through secondary air passage 91 to the inner chamber 79a of the valve housing 74, the valve plate 80 releases the valve hole 78a. As a consequent, secondary air sucked from the air cleaner 21 through the air duct 90 to the outer chamber 79b passes through the valve hole 78a, and then through the inner chamber 79a and secondary air passage 91, then inhaled into the exhaust port 27e. When the positive pressure component of the pulsating waves is transmitted through secondary air passage 91 to the inner chamber 79a of the valve housing 74, the valve plate 80 closes the valve hole 78a, and thus the backflow through secondary air passage 91 toward the air cleaner 21 is prevented. Secondary air supplied to the exhaust port 27e in this way proceeds to the catalytic converter 30 while being mixed with exhaust gas flowing through the exhaust system, and involved in elimination of oxidation of harmful component such as unburned gas or the like contained in exhaust gas.
[0036]
Incidentally, the valve housing 74 provided continuously with the head cover 35 is to be disposed next to the outer sidewall of the cylinder head 34, and thus the possibility of in-vehicle layout of the engine E may be expanded without increasing the length of the engine E in the direction along the axis L of the cylinder. In addition, the valve housing 74 does not come into contact with the outer wall of the cylinder


head 34 and a space exist therebetween, high heat from the cylinder head 34 is hardly transmitted to the valve housing 74, and thus the one-way valve 75 in the valve housing 74 is prevented from endamaged by heat from the cylinder head 34 to ensure the durability of the one-way valve 75.
[0037]
Since secondary air passage 91 connecting the inner chamber 79a of the valve housing 74 to the exhaust port 27e is formed on the head cover 35 and the cylinder head 34 in itself, piping between them is not necessary, thereby simplifying the structure. In addition, the valve housing 74 provided continuously with the lower portion of the head cover 35 occupies the position relatively close to the exhaust port 27e extending downward from the combustion chamber 26, whereby secondary air passage 91 may be shortened, and thus the flow path resistance is also decreased, thereby ensuring supply of secondary air to the exhaust port 27e and contributing to improve the effectiveness of purification of exhaust gas.
[0038]
In addition, since the valve housing 74 is disposed on the same side as the sidewall of the cylinder head 34 on which the ignition plug 48 is screwed, the dead space around the ignition plug 48 can be utilized for disposing the valve housing 74, whereby upsizing of the engine E can be prevented.
[0039]

Referring now to Fig. 3 to Fig. 7, a breather unit for circulating a blow-by gas generated in the crankcase 33 in the intake system including the air cleaner 21 will be described.
[0040]
In contrast to the valve housing 74, the breather chamber 95 is provided between the upper portion of the head cover 35 and the cylinder head 34. The breather chamber 95 is defined by the upper sidewalls 34a, 35a of the cylinder head 34 and the head cover 35, and the bulkheads 34b, 35b uprising from the opposite surfaces of the cylinder head 34 and the head cover
35 to abut against with each other, and the lower portion of the bulkhead 35b on the head cover 35 side is formed with a inlet 98a and an oil return port 98b arranged above and below so as to connect the breather chamber 95 to the motion valve chamber
36 in the shape of a notch, and the inlet 98a and the oil return port 98b are disposed as far from the timing chamber 40 as possible. The outer sidewall of the upper portion of the breather chamber 95 is fixed with an outlet pipe 99 passing therethrough, to which the breather pipe 100 in communication with the air cleaner 21 is connected.
[0041]
Each opposed surface of the cylinder head 34 and the head cover 35 is formed with one or more bulkheads 34c, 35c for deflecting airflow in the breather chamber 95. Accordingly, the breather chamber 95 is formed as a maze.


[0042]
Therefore, while the engine E is in operation, a blow-by gas leaked from the combustion chamber 26 through the sliding surface of the piston 42 into the crankcase 33 is moved through the timing chamber 40 to the motion valve chamber 36, then mainly from the inlet 98a into the breather 95, and subsequently proceeds to the outlet pipe 99 while being deflected by the bulkheads 34c, 35c. Meanwhile, when lubricating oil mist generating in the motion valve chamber 36 along with the operation of the timing transmission unit Ti and the motion valve mechanism Vm is mixed into the blow-by gas, and then entered into the breather chamber 95, oil mist mixed in the blow-by gas is separated and liquidized when being deflected in stream by the bulkheads 34c, 35c, and then flows on the bottom surface of the breather chamber 95 and is flown out mainly from the oil return port 98b at the lowermost portion into the motion valve chamber 36. On the other hand, the blow-by gas with oil removed therefrom passes through the outlet pipe 99 and the breather pipe 100 and is sucked into the air cleaner 21, where it is purified and is sucked again by the engine E for combustion.
[0043]
Since the breather chamber 95 is formed between the upper portion of the head cover 35 provided with a valve housing 74 continuously at the lower portion thereof and the cylinder head 34, it can be formed in a desired configuration without being


disturbed by the valve housing 74, and thus entering of lubricating oil into the breather chamber 95 can be minimized. In addition, since the breather chamber 95 is defined by the upper side walls 34a, 35a of the cylinder head 34 and the head cover 35, and the bulkheads 34b, 35b projecting from their opposed inner walls, there is no need to provide a special breather chamber forming member, which contributes to simplification of the structure.
[0044]
Referring now to Fig. 2 and Fig. 3, the cooling unit for the engine E will be described.
[0045]
A rotor 69 is fixed on the side of the right end of the crankshaft 31, and a stator 70 constituting an AC generator 68 in cooperation with the rotor 69 is connected to the supporting plate 73 that is to be joined to the side wall of the crankcase 33 with a bolt in such a manner that it is surrounded by the rotor 69. A cooling fan 71 is fixed on the right end of the crankshaft 31 at the outer position with respect to the AC generator 68, and a radiator 72 is disposed in such a manner that the cooling fan 71 is interposed between the AC generator 68 and the radiator 72. The radiator 72 is mounted to the engine body 25 via a core shroud 81 that surrounds the cooling fan 71.
[0046]
The radiator 72 and the water pump 110 for circulating


cooling water through the coolant passage including the water jacket 82 of the engine 25 are provided on one side of the cylinder head 34. The water pump 110 has a pump housing 111 comprising a inner half of housing Ilia projecting toward the motion valve chamber 36 and an outer half of housing 111b to be connected to the sidewall of the cylinder head 34 on one side together with the inner half of housing Ilia, and a pump chamber 114 is formed in the outer half of housing 111b.
[0047]
Both ends of a supporting shaft 112 is supported by the opposed walls of both halves of housing 111a, 111b, and a pump impeller 115 to be stored in the pump chamber 114 is secured on the cylindrical pump shaft 113 rotatably supported by this supporting shaft 112. The outer half of housing 111b is formed with a discharge pipe 116 lead to the outer peripheral portion of the pump chamber 114, and is provided with a thermostat 117 for opening and closing the discharge pipe 116. when the valve of the thermostat 117 is opened, cooling water sucked from the radiator 72 into the central portion of the pump chamber 114 is pressurized by the rotation of the pump impeller 115 and supplied to the water jacket 82 through the discharge pipe 116 to cool the engine 25 down. The cooling water after cooling is circulated to the radiator 72.
[0048]
The side cover 118 to be joined to the outer side surface


of the outer half of housing 111b is provided with a inlet pipe 119 of the by-pass water channel for returning cooling water discharged from the pump chamber 114 directly into the water jacket 82 without passing through the radiator 72 when the valve of the thermostat 117 is closed.
[0049]
The magnetic pump drive unit 120 for driving the water pump 110 is constructed between the driven sprocket 47 and the water pump 110 as follows.
[0050]
A stepped cylindrical magnet holder 121 is fixed on the outer side surface of the central portion of the driven sprocket 47. The magnet holder 121 is formed by press-molding a non-magnetic stainless steel plate, and an annular driving magnet 122 is fixed on the inner peripheral surface of the larger diameter portion by press-fitting or by adhesion.
[0051]
An annular driven magnet 123 to be fixed on the pump shaft 113 is stored in the inner half of housing 111a, simultaneously, the driven magnet 123 is disposed concentrically with the driven magnet 122 with the inner half of housing 111a interposed therebetween. On both end surfaces and the outer peripheral surface of the driven magnet 123, a covering body 124 of synthetic resin is coupled by mode coupling, and the pump impeller 115 is integrally connected to one end of the covering


body 124.
[0052]
Therefore, when the driven sprocket 47 rotates the drive magnet 122 via the magnet holder 121, the driven magnet 123 is rotated by a magnetic force exerted between the drive magnet 122 and the driven magnet 123 in the same direction as the drive magnet 122, thereby rotating the pump impeller 115.
[0053]
Though the embodiment of the present invention has been described thus far, the present invention is not limited thereto, and various modifications in design is possible without departing from the scope of the invention. For example, it is also possible to use the oil return hole also as a inlet 98a of the breather chamber 95, and the oil return hole 98b may be omitted. The prevent invention may also be applicable to various types of vehicles other than the motorcycles V described above, for example, cyclecars or the like.
[0054] [Advantages of the Invention]
As described above, according to the first characteristic of the present invention, in a secondary air supply system for purifying exhaust emission from engine wherein a head cover is joined to the cylinder head for defining a motion valve chamber for accommodating a motion valve mechanism therebetween, and valve means is provided on the head cover for supplying


secondary air for purifying exhaust gas to a exhaust port formed on the cylinder head, a valve housing is provided continuously on one side of the head cover so as to lie next to, but not to come into contact with, the outer surface of the cylinder head, and the valve means is accommodated in the valve housing. Therefore, the possibility of in-vehicle layout of the engine may be expanded without increasing the length of the engine along the direction of the axis of the cylinder. In addition, since the valve housing is not in contact with the outer sidewall of the cylinder head, high heat of the cylinder head is hardly transmitted to the valve housing, and thus the valve means in the valve housing is prevented from being endamaged by heat from the cylinder head, thereby ensuring the durability of the valve means.
[0055]
According to the second characteristic, the engine is disposed in such a manner that the axis of the cylinder lies generally horizontally and the exhaust port is faced downward from the combustion chamber, the valve housing is provided continuously from the lower portion of the head cover that is to be joined to the cylinder head of the engine, and a breather chamber connecting between a inlet that is in communication with the motion valve chamber and a outlet disposed at the higher level than the inlet and led to the outside with a maze of passages for separating lubricant oil mist from a blow-by gas


introduced from the motion valve chamber is provided between the upper portion of the head cover and the cylinder head. Therefore, the valve housing is positioned relatively near the exhaust port, and consequently, secondary air passage may be shortened, and thus the flow path resistance is decreased, thereby ensuring supply of secondary air to the exhaust port and contributing to improve the effectiveness of purification of exhaust gas.
[0056]
According to the third characteristic of the present invention, the valve housing is disposed on the side of the cylinder head on which the ignition plug is to be mounted. Therefore, the dead space around the ignition plug can be utilized for disposing a valve housing, whereby upsizing of the engine can be prevented.


[Reference Numerals] E...Engine
L...axis of the cylinder Vm...motion valve mechanism 26...combustion chamber 27e...exhaust port 34...cylinder head 35...head cover

36...motion valve chamber
48...ignition plug
74...valve housing
75...valve means (one-way valve)
95...breather chamber
98a...inlet of the breather chamber
99...outlet of the breather chamber


We claim:
1. A secondary air supply system for purifying exhaust emission from engine wherein a head cover (35) is joined to a cylinder head (34) for defining a motion valve chamber (36) for accommodating a motion valve mechanism (Vm) therebetween, and valve means (75) is provided on the head cover (35) for supplying secondary air for purifying exhaust gas to a exhaust port (27e) formed on the cylinder head (34), characterized in that a valve housing (74) is provided continuously on one side of the head cover (35) so as to lie next to, but not to come into contact with, the outer surface of the cylinder head (34), and the valve means (75) is accommodated in the valve housing (74).
2. A secondary air supply system for purifying exhaust emission from engine as claimed in Claim 1, wherein the engine (E) is disposed in such a manner that the axis of the cylinder (L) lies generally horizontally and the exhaust port (27e) is faced downward from the combustion chamber (26), the valve housing (74) is provided continuously from the lower portion of the head cover (35) that is to be joined to the cylinder head (34) of the engine (E), and a breather chamber (95) connecting a inlet (98a) that is in communication with the motion valve chamber (36) and a outlet (99) disposed at the higher level than the inlet (98a) and led to the outside with a maze of passages for separating lubricant oil mist from a blow-by gas introduced from the motion valve chamber (36) is provided between the upper portion of the head cover (35) and the cylinder head (34).
3. A secondary air supply system for purifying exhaust emission from engine as claimed in Claim 1 or 2, wherein the valve housing (74) is disposed on the side of the cylinder head (34) on which the ignition plug (48) is to be mounted.


4. A secondary air supply system for purifying exhaust emission substantially as herein described with reference to the accompanying drawings.
Dated this 29th day of November, 2001.
[JAYANTA PAL] OF REMFRY & SAGAR ATTORNEY FOR THE APPLICANTS

Documents:

1144-mum-2001-absrtact.doc

1144-mum-2001-abstract(29-11-2001).doc

1144-mum-2001-abstract(29-11-2001).pdf

1144-mum-2001-abstract.pdf

1144-mum-2001-cancelled pages(02-02-2007).pdf

1144-mum-2001-claim(granted)-(29-11-2001).doc

1144-mum-2001-claims(granted)-(02-02-2007).pdf

1144-mum-2001-claims.doc

1144-mum-2001-claims.pdf

1144-mum-2001-correspondence(02-02-2007).pdf

1144-mum-2001-correspondence(ipo)-(26-09-2006).pdf

1144-mum-2001-correspondence(ipo).pdf

1144-mum-2001-correspondence.pdf

1144-mum-2001-description(granted).doc

1144-mum-2001-description(granted).pdf

1144-mum-2001-drawing(24-12-2001).pdf

1144-mum-2001-drawing.pdf

1144-mum-2001-form 1(02-02-2007).pdf

1144-mum-2001-form 1-cancelled-29-11-2001.pdf

1144-mum-2001-form 1.pdf

1144-mum-2001-form 18(16-11-2005).pdf

1144-mum-2001-form 18.pdf

1144-mum-2001-form 2(granted)-(02-02-2007).doc

1144-mum-2001-form 2(granted)-(02-02-2007).pdf

1144-mum-2001-form 2(granted).doc

1144-mum-2001-form 2(granted).pdf

1144-mum-2001-form 2(title page).pdf

1144-mum-2001-form 3(02-02-2007).pdf

1144-mum-2001-form 3(29-11-2001).pdf

1144-mum-2001-form 3.pdf

1144-mum-2001-form 5(29-11-2001).pdf

1144-mum-2001-form 5.pdf

1144-mum-2001-petition under rule 137.pdf

1144-mum-2001-petition under rule 138(02-02-2007).pdf

1144-mum-2001-petition under rule 138.pdf

1144-mum-2001-power of authority(02-02-2007).pdf

1144-mum-2001-power of authority(08-03-2002).pdf

1144-mum-2001-power of authority.pdf

abstract1.jpg


Patent Number 210386
Indian Patent Application Number 1144/MUM/2001
PG Journal Number 41/2007
Publication Date 12-Oct-2007
Grant Date 03-Oct-2007
Date of Filing 29-Nov-2001
Name of Patentee HONDA GIKEN KOGYO KABUSHIKI KAISHA
Applicant Address 1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO,
Inventors:
# Inventor's Name Inventor's Address
1 KENJI OKI C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA,
PCT International Classification Number F01N 3/34
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2001-001827 2001-01-09 Japan