DESC:FIELD OF INVENTION
[0001] The present invention relates to an internal combustion engine for a step through vehicle and more particularly to a breather chamber created in-between crankcase and a cover magneto of said internal combustion engine.
BACKGROUND OF INVENTION
[0002] The present scooter engine which is inclined forward, therein the transmission (CVT) is provided in-between a crankshaft and clutch shaft and is covered by a cover variator. Due to piston action, blow by gas generated inside the crankshaft room, which needs to be removed to avoid, built up of excessive vapor pressure. In such scooter engines breather chamber is provided on cylinder head cover due to this arrangement engine height is increased. Moreover, due to swinging engine, restricting the engine height is required to construct and give more volume to a utility box. In such a scooter engine, a compromise has to be made between the breather chamber volume and utility box volume. Hence, it is desirable to increase the breather chamber space without compromising with the utility box volume.
SUMMARY OF THE INVENTION
[0003] In order to obviate the limitations and the problems associated with the prior art, the current invention discloses a breather chamber arranged between crankcase Right and a cover magneto. A cover magneto is a cover which is attached to the crankcase Right and covers the flywheel magneto. Due to piston action, blow by gas generated inside the crankshaft room and gas passes through the ventilation provided in the crankcase and passes to cover magneto, which further passes to air, filter.
BRIEF DESCRIPTION OF DRAWINGS
[0004] Figure 1 illustrates a typical type two-wheeler.
[0005] Figure 2 illustrates engine assembled on the vehicle.
[0006] Figure 3 illustrates formation and routing of formed breather gas.
[0007] Figure 4 illustrates exploded view of region channelizing the breather gas.
[0008] Figure 5 illustrates perspective view of cover magneto with breather gas flow.
[0009] Figure 6 illustrates oil splash wall in the cover magneto.
[00010] Figure 7 illustrates pulsar coil orientation as per the prior art.
[00011] Figure 8 illustrates pulsar coil orientation as per the current invention.
[00012] Figure 9 illustrates the splash wall and pulsar coil.
DETAILED DESCRIPTION OF THE INVENTION
[00013] In a scooter engine either air cooled or liquid cooled which is equipped with a one way clutch starting mechanism to start the engine, a fly wheel, and a magneto assembled in crankshaft right side, is covered by a cover magneto followed by a fan, a fan housing and a radiator assembly. In this arrangement cam shaft driven water pump assembly is arranged on cylinder head. A breather chamber is designed above the fly wheel magneto and is split in two halves with one half in crankcase right side and another half inside cover magneto. An intermediate gasket is provided in-between the said crankcase and the cover magneto. The gasket is further provided with small holes to increase blow by gas velocity and drain the oil fumes to the oil sump through an oil return path. In this arrangement oil pump assembly, cam chain and sprocket cam chain are assembled on left side of the engine.
[00014] Figure 1 illustrates a two-wheeled vehicle 1 with a rear wheel 2, an engine 3, an air filter 4, front wheel 5, floorboard 6, front wheel 7, utility box 8, side cover 9, front suspension 10, and rear suspension 11, grab rail 12, tail lamp 13 and rider seat 14. In such a vehicle 1, the fuel tank is placed below the rider seat 14. The cylinder head and the cylinder block of the engine 3 are located below the utility box and besides air filter 4 in the front direction of the vehicle. The main advantage of the proposed breather chamber is to increase the available space for the utility box by shifting the breather chamber from the cylinder head region to above the fly wheel magneto and is split in two halves with one half in crankcase right side and another half inside cover magneto.
[00015] Figure 2 illustrates a fuel tank 3, engine 3, exhaust muffler 21, breather port 22, crankcase right component 23; crankcase left component 24, cylinder head 25, cylinder block 26, breather hose 27 and an air filter 4. Due to piston action inside the cylinder block 26, blow by gases are generated inside the crankshaft room which needs to be removed to avoid built up of excessive vapor pressure of the blow by gas. According to the current invention, the blow by gases are transferred from the breather port 22, using the breather hose 27 to air filter 4 via a breather chamber in-between crankcase right and cover magneto 43.
[00016] Figure 3 further illustrates the crankcase left component 24, crankcase right component 23, gasket cover magneto 33, cylinder block 26, cylinder head 25, breather inlet chamber from crankcase 36, breather housing 37 and breather pipe 38 to an air filter 4. The gasket cover magneto 33 is sandwiched between the crankcase right component 23 and a cover magneto 43 (illustrated further in Figure 4). The gasket cover magneto 33 is further provided with plurality of holes to overlap with the breather gas channel formed in-between the crankcase right component 23 and a cover magneto 43. The breather gas flows from the cylinder block and crankshaft region to the region between the said crankcase right component 23 and a cover magneto 43 called as the breather chamber through these holes.
[00017] Figure 3 illustrates the flow of breather into the breather chamber through breather inlet chamber from crankcase 36, breather housing 37 and finally being purged to the air filter 4 through the breather pipe 38. The breather inlet chamber from crankcase 36 and breather housing 37 are interconnected through holes hence, from the breather inlet chamber from crankcase 36 till the breather pipe 38, the complete region, collectively forms the breather chamber.
[00018] Figure 4 further shows the exploded view of essential components to illustrate flow of the breather gas according to the current invention. Figure 4 further shoes crankcase left side inner 41, crankcase left side outer 42, and crankcase right component 23, and cover magneto 43, breather inlet chamber from crankcase 36, breather housing 37 and breather pipe to air filter 4. The crankcase left side outer 42, crankcase right component 23, gasket cover magneto 33 and cover magneto 43 are assembled one after another to produce a breather housing 37 where all the blow by gases are stored before being sent to the air filter 4 through the breather pipe 38. The breather inlet chamber from crankcase 36 and breather housing 37 are interconnected through holes hence, from the breather inlet chamber from crankcase 36 till the breather pipe 38, the complete region, collectively forms the breather chamber.
[00019] Figure 5 further clearly illustrates the breather inlet chamber from crankcase 37 inside the cover magneto 43. Figure 6 further illustrates the cover magneto 43, flow of oil 62, and splash wall 61 to reflect the oil from reaching out to pulsar coil (further explained in Figure 7 & Figure 8) electrical cable routing area. Normally, in internal combustion engine, the pulsar coil is located at maximum possible height to avoid entry of oil into the electrical cables. Moreover, in the current invention, since it is desirable to position the breathing chamber at maximum possible height hence, to provide the height to the breather chamber, the pulsar coil is located at a smaller height than the breather chamber 37. Hence, to achieve the efficiency of the breather housing, instead of located at a right angle, the pulsar coil is positioned at an acute angle with respect to a horizontal axis passing through the crankshaft axis.
[00020] Figure 7 further illustrates the positioning of the pulsar coil according to the existing prior art design wherein the breather housing is made out of the space inside cylinder head. Figure 8 further illustrates the positioning of the pulsar coil according to the current invention and as described previously. Figure 7 shows crankcase left side outer 42, pulsar coil 71, crankshaft axis 72 and magneto 73. Figure 8 further illustrates the cover magneto 32, crankshaft axis 72, pulsar coil 82 and splash wall 83. Figure 9 further illustrates the pulsar coil 82 and splash wall 83. As it is clearly illustrated in Figure 7, Figure 8 & Figure 9, the pulsar coil has been positioned at an acute angle to the horizontal axis passing through the crankshaft to make more space for the breather housing 37.
,CLAIMS:We claim:
1. A breather housing (37) in an internal combustion engine (3), the engine (3) comprising:
a combustion chamber wherein combustion of fuel takes place and which is enclosed by a crankcase right side (23) and crankcase left side (24);
a magneto mounted on a crankshaft which generates electricity when the crankshaft of the vehicle rotates; the magneto is covered by a cover magneto (43);
a breather gas passage which links the combustion chamber to an air filter (4) through a breather housing (37) thereby directing the breather gas generated from the combustion chamber to the air filter (4);
characterized in that:
the said breather housing (37) which is filled with the breather gas before being purged out to the air filter (4) is sculpted out of a region partially from the crankcase (23,24) and the said cover magneto (43).
2. The breather housing (37) in an internal combustion engine (3) as claimed in Claim 1 wherein a splash wall (61) is located in the cover magneto (43) to reflect the oil contained in the breather gas.
3. The breather housing (37) in an internal combustion engine (3) as claimed in Claim 1 wherein a pulsar coil (71) on the cover magneto (43) is positioned at an acute angle with respect to a horizontal axis passing through a crankshaft axis (72).