CN101349194B - Improved single-cylinder four-stroke 50cc engine for motorcycle - Google Patents

Abstract

The invention provides an improved single-cylinder four-stroke 50cc engine for motorcycles, which belongs to the technical field of motorcycle engine and mainly solves the problems that the prior 139QMB engine is low in dynamic indexes, high in noise, poor in reliability, and so on. The improved part of the 50cc engine relates to a heat part and an air filter, and adopts an integral type cylinder head to reduce the friction loss of a bearing for a camshaft, so as to reduce operation noise; an air duct structure of a cylinder head is optimized; a valve, a spring for the valve, a spring seat for the valve, a piston, a piston pin and other components are designed to be light in weight; the gas distribution phase position and the volume of a combustion chamber are optimized; the thickened piston ring land design is adopted for the piston; a twisted ring is adopted as a piston ring, and as oil ring combination lowers the height by 25 percent, the friction loss of the piston ring is reduced; and a brand new air filter structure is provided. Compared with the engines of the same type, the engine has the advantages of little whole engine vibration, low noise, low oil consumption, high output power and torque, as well as obviously raised power performance.

Description

A kind of modified model motorcycle single-cylinder four-stroke 50cc motor

Technical field

The present invention relates to a kind of motorcycle engine technical field, specifically is modified model motorcycle 139QMB motor.

Background technique

Recently, the market demand of four-stroke 50cc pedal motorcycle presents the good trend of rising.

The 139QMB motor of existing volume production is a present a motor more salable in country's bulletin catalogue product, but this engine performance can't satisfy the more and more harsher requirement in market.The factor that influences engine performance is more, all can exert an influence to the engine power size such as the design of cylinder head, the design of firing chamber, the design of gas handling system, the aspects such as quality of relevant movement parts.By analysis, there is the space of improvement aspect above-mentioned really in this machine.

Summary of the invention

The invention provides a kind of modified model motorcycle with single-cylinder four-stroke 50cc motor, it can solve that existing 139QMB motor exists is short of power, the problem of aspects such as noise is higher, less reliable.

Technological scheme of the present invention is: this kind modified model motorcycle single-cylinder four-stroke 50cc motor, it is characterized in that,

Camshaft retainer and cylinder head adopt monolithic construction;

The center of rocking arm contact sliding length is near the valve stem center, set the intake valve angle and be 24.7 ° ± 10 ', the exhaust valve angle is 27.2 ° ± 10 ', inlet and exhaust valve guide pin bushing shaft axis position of intersecting point is positioned at plane, cylinder centerline spontaneous combustion chamber to cylinder direction 16mm place;

The inlet and outlet road, is avoided wedge angle and is avoided the circular arc of radius less than the air flue radius to the level and smooth flaring of air inlet-outlet pipe side from combustion chamber side;

Toward spark plug direction lateral deviation 1.9mm, the spark plug offside squeezes the stream interface width and increases 2mm the firing chamber centre of sphere from cylinder centerline;

Inlet and outlet gate seat seal band angular setting is between 89 °～90 °; Valve stem directly is φ 4mm, 91 °～90 ° of valve sealing band angles, and the intake valve umbrella directly is φ 20mm, the exhaust valve umbrella directly is φ 16.5mm;

The design of distribution cam axle type shape line, distribution rocking arm ratio is 24: 17; Port timing: the intake valve angle of advanced opening is 10 degree, and the late angle of closing of intake valve is 15 degree, and the exhaust valve angle of advanced opening is 25 degree, and angle, exhaust valve pass in evening is 1.5 degree;

To valve, valve spring, cotter seat, piston, wrist pin light-weight design, the same parts quality of the former 139QMB of total mass ratio of these parts reduces by 25%;

Piston mass reduces by 20% than original, and piston pin hole is φ 10mm, and piston pin external diameter is φ 10mm, and the connecting rod small end aperture is φ 10mm; Piston one ring adopts twist type ring, and assembling back distortion angle is 20 °, and piston one ring thickness is 0.8mm, and piston two ring thicknesses are 0.8mm, and oil ring thickness is 1.5mm;

Empty filter coupling PD20J Carburetor; Described empty filter, its housing and cap are triangle, and element kit is arranged between housing and the cap inside, form the main chamber of sky filter in case side, form the secondary chamber of sky filter in the cap side; Be provided with cylinder head secondary air compensating connecting tube in main chamber upper front end, be provided with crankcase gas blowby connecting tube in its underpart, crankcase gas blowby connecting tube is connected with crankcase gas blowby condensation chamber, and the opening of crankcase gas blowby condensation chamber communicates with main chamber; Minimum point place in main chamber lower rear is provided with oil-collecting/water pipe.

The invention has the beneficial effects as follows: to increase the cylinder head composite rigidity, reducing the camshaft bearing frictional loss is the integrated type cylinder head design of purpose; To increase volumetric efficiency Φ c is that the air inlet of purpose is an optimal design, contains structure optimizations such as sky filter, intake duct; Face amount and thermal efficiency of cycle are that the distribution system and the burning of purpose are optimal design during with the raising inlet and exhaust valve, contain camshaft, rocking arm, valve, chamber structure optimization; To reduce reciprocal inertia loss is the component light-weight design of purpose, contains the structure optimization of valve, piston, wrist pin, connecting rod; To reduce frictional loss is the piston ring group optimal design of purpose, and above-mentioned measure can solve that existing 139QMB motor exists is short of power, the problem of aspects such as noise is higher, less reliable.Engine performance is obviously improved, to satisfy the more and more harsher requirement in market.This machine is compared with motor of the same type, and complete machine vibrations are light, noise is lower, and oil consumption is low, and output power, moment of torsion are bigger, and power performance obviously improves.

Description of drawings

Fig. 1 is a whole plan structure schematic representation of the present invention;

Fig. 2 is A among Fig. 1-A partial schematic sectional view;

Fig. 3 is a B place partial enlarged drawing among Fig. 2;

Fig. 4 is monolithic construction of the present invention and inlet and exhaust valve angular orientation schematic representation;

Fig. 5 is the sectional view of chamber structure of the present invention;

Fig. 6 is an intake valve seal band angle schematic representation of the present invention;

Fig. 7 is an exhaust valve seal band angle schematic representation of the present invention;

Fig. 8 is rocking arm combination schematic representation;

Fig. 9 is that camshaft intake and exhaust control position concerns schematic representation;

Figure 10 is the piston schematic representation;

Figure 11 is piston one a ring part sectioned view;

Figure 12 is the structural representation of filter cleaner;

Figure 13 removes part-structure schematic representation behind the cap for filter cleaner;

Figure 14 is a filter case inside structure schematic representation;

Figure 15 is filter case cover inboard and suction tude mounting structure schematic representation.

Among Fig. 1-3: 1 integrated type cylinder head, the combination of 2 distribution cam axles, 3 intake valves, 4 exhaust valves, 5 valve spring, 6 Carburetors, 7 empty filters, 8 pistons, 9 wrist pins, 10 piston rings, one ring, 11 piston rings, two rings, the combination of 12 piston ring oil rings, 13 crank rod assemblies, 14 cylinder block, 15 cylinder heads stop up.

Among Figure 12-15: 71 filter cases; 72 filter case covers; 73 suction tude; 74 steam outlet pipes; 75 element kits; 76 main chambeies; 77 secondary chambeies; 78 cylinder head secondary air compensating connecting tubes; 79 crankcase gas blowby connecting tubes; 710 crankcase gas blowby condensation chambers; 711 openings; 712 oil-collectings/water pipe.

Embodiment

Modified model motorcycle 139QMB motor comprises integrated type cylinder head 1, distribution cam axle combination 2, intake valve 3, exhaust valve 4, valve spring 5, Carburetor 6, empty filter 7, piston 8, wrist pin 9, piston ring one ring 10, piston ring two rings 11, piston ring oil ring combination 12, crank rod assembly 13, cylinder block 14, cylinder head stops up 15, sees Fig. 1-3.

Use the improvement of 139QMB engine cylinder head at motorcycle:

1, camshaft retainer and cylinder head integral design.Material selection ZL104 casts out with metal mould cast method is disposable.The camshaft bearing that has caused when having avoided camshaft bump fault that split type retainer causes when cylinder head bolton moment of torsion is on the low side and the cylinder head bolt torque bigger than normal fault that is crushed to death.Guaranteed the rigidity of cylinder head combination, camshaft hole, rocker shaft hole and cylinder center relative position size machining precision have been guaranteed, thereby guaranteed port timing within scope of design, reduced the bump of camshaft operation process, effectively reduced the cylinder head noise.As Fig. 4.

2, for reduce the sliding friction distance of rocking arm contact and valve rod end surface as far as possible, and the center that makes rocking arm contact sliding length is near the valve stem center, reduce the lateral pressure of valve stem to valve guide, set best valve angle, the intake valve angle is 24.7 ° ± 10 ', the exhaust valve angle is 27.2 ° ± 10 ', inlet and outlet door guide pin bushing axle center position of intersecting point is positioned at cylinder axis 16mm place.As Fig. 4.

3, according to combustion-chamber shape and inlet and outlet door head dimensions, strengthen inlet and outlet road sectional area, and (intake duct is expanded to Φ 18mm by Φ 17mm to the level and smooth flaring of air inlet-outlet pipe side from combustion chamber side to make the inlet and outlet road, air outlet flue is expanded to Φ 15mm by Φ 13.5mm), avoid wedge angle and radius circular arc simultaneously less than the air flue radius.Such design, intake duct is equivalent to the draw, can increase air-flow velocity, increases the turbulent flow of air-flow in cylinder; Air outlet flue is equivalent to expander, can reduce exhaust airstream speed, reduces exhaust noise.As Fig. 4.

4, chamber structure optimization.The firing chamber centre of sphere is toward spark plug lateral deviation 1.9mm, and the spark plug offside squeezes the stream interface width and increases 2mm, can shorten the spark propagation length like this, improves velocity of propagation of flame, thereby improves the burning degree of constant volume, improves combustion efficiency.Unnecessary screw thread processing is removed near the spark plug, can effectively reduce motor HC discharge amount.As Fig. 5.

5, inlet and outlet gate seat seal band angular setting is 90 ° (0 ° ,-1 °); The seal band angular setting of the intake valve that cooperates with gas inlet outlet valve base, exhaust valve is that 90 ° (0 ° ,+1 °) match.As Fig. 6, Fig. 7.Realized that valve contacts with the line of valve seat endless belt, improved sealability, improved the complete machine compression pressure.

Strengthen the intake and exhaust port sectional area, reduce the valve stem diameter, increase intake valve umbrella footpath, increase exhaust valve umbrella footpath to φ 16.5mm to φ 20mm to φ 4mm.Valve maximum lift 6.0mm; Valve relative lift: advance 0.34mm, row 0.42mm; Air inlet Mach index Z is 0.34, and exhaust Mach index Z is 0.42.

Fig. 8 rocking arm combination schematic representation; Fig. 9 is that camshaft intake and exhaust control position concerns schematic representation.The design of distribution cam axle type shape line, the distribution rocking arm compares 24:17.Port timing: intake valve angle of advanced opening 10 degree, late angle 15 degree that close of intake valve, angle, exhaust valve angle of advanced opening 25 degree exhaust valve pass in evening 1.5 degree.Reduce the sliding friction distance of rocking arm contact and valve rod end surface simultaneously, and the center that makes rocking arm contact sliding length reduces the lateral pressure of valve stem to valve guide near the valve stem center as far as possible.21,22 be respectively camshaft air inlet, exhaust control cam.

Piston 8 (see figure 10) mass ratioes are original to reduce by 20%, and piston pin hole is φ 10, piston pin external diameter φ 10, and connecting rod small end aperture φ 10 is to cooperate the wrist pin after the lightweight; Piston ring one ring 10 (seeing Figure 11) adopt twist type ring, about 20 ° of assembling back distortion angles, and piston one ring thickness 0.8mm, piston two ring thickness 0.8mm, oil ring thickness is 1.5mm;

As shown in Figure 12-15, improve structure for filter cleaner, filter cleaner comprises housing 71, cap 72, suction tude 73, steam outlet pipe 74 and element kit 75, described housing 71 and cap 72 are triangle, element kit 75 is arranged between housing 71 and cap 72 inside, in the main chamber 76 of housing 71 sides formation filter cleaner, form the secondary chamber 77 of filter cleaner in cap 72 sides; 76 upper front end are provided with cylinder head secondary air compensating connecting tube 78 in main chamber, its caliber is φ 6, be provided with crankcase gas blowby connecting tube 79 in its underpart, crankcase gas blowby connecting tube 79 is connected with crankcase gas blowby condensation chamber 710, and the opening 711 of crankcase gas blowby condensation chamber 710 communicates with main chamber 76; Minimum point place in main chamber 76 lower rear is provided with oil-collecting/water pipe 712, and its volume is 30ml.

Described steam outlet pipe 74 is the uniform section bend pipe of internal diameter φ 34, and the one end is provided with flange plate and links to each other with Carburetor, and the other end is horn-like and main chamber 76 and is connected.

Described suction tude 73 is fixed on cap 72 front portions, suction tude 73 is the uniform section straight tube of internal diameter φ 25, and length is 90mm, and the inlet end of suction tude 73 stretches out cap and becomes the angular cut shape, its otch side is towards cap 72 inboards, and 77 inside, secondary chamber are stretched in the outlet side of suction tude 73.

Described filter cleaner internal cavity total measurement (volume) is 2.22L, and wherein main chamber 76 volumes are 1.12L, and secondary chamber 77 volumes are 1.1L.The size of filter cleaner internal cavity is to absorbing the induction noise of suction tude 73, and forming the reflection condensation wave has bigger effect, and for the 50cc motor, the cavity volume of filter cleaner is better to reducing the induction noise effect greater than 2.0L the time.

During work, ambient air enters secondary chamber 77 through suction tude 73, after element kit 75 filters, enters main chamber 76 again, enters Carburetor through steam outlet pipe 74 again.The gas blowby that enters crankcase gas blowby condensation chamber 710 through crankcase gas blowby connecting tube 79 is through after the Oil-gas Separation, the air of separating enters main chamber 76 through opening 711, waste oil after the separation flows in the oil-collecting/water pipe 712 at rear portion along housing 71 inwalls of filter cleaner, and oil-collecting/water pipe 712 will regularly empty.The gas of sending here through cylinder head secondary air compensating connecting tube 8 enters filter cleaner master chamber 76, and the secondary air compensating noise can be effectively eliminated in main chamber 76.

The circulation air inflow of bringing at air flue and port timing optimization and empty filter optimization strengthens, the Carburetor that has mated throat diameter φ 20mm, and foam tube, main jet, idle metering jet, the air jet of Carburetor have been mated, make the power performance of complete machine good, middle low speed constant-speed fuel economy is lower than 1.6L/100km.

Valve stem footpath φ 4mm, valve spring 5 are single spring, piston mass 39g, and wrist pin 9 specifications are φ 10 * 1.5 * 31, quality 11.5g, and connecting rod small end aperture φ 10mm, quality alleviates 5g.Above-mentioned parts lightweight measure effectively reduces reciprocal inertia loss and frictional loss.

Valve, valve spring, cotter seat, piston, wrist pin component light-weight design, the same parts quality of the former 139QMB of total mass ratio reduces by 25%.

Claims (1)

1. a modified model motorcycle is characterized in that with single-cylinder four-stroke 50cc motor camshaft retainer and cylinder head adopt monolithic construction;

The center of rocking arm contact sliding length is near the valve stem center, set the intake valve angle and be 24.7 ° ± 10 ', the exhaust valve angle is 27.2 ° ± 10 ', inlet and exhaust valve guide pin bushing shaft axis position of intersecting point is positioned at plane, cylinder centerline spontaneous combustion chamber to cylinder direction 16mm place;

The inlet and outlet road, is avoided wedge angle and is avoided the circular arc of radius less than the air flue radius to the level and smooth flaring of air inlet-outlet pipe side from combustion chamber side;

Toward spark plug direction lateral deviation 1.9mm, the spark plug offside squeezes the stream interface width and increases 2mm the firing chamber centre of sphere from cylinder centerline;

Inlet and outlet gate seat seal band angular setting is between 89 °～90 °; Valve stem footpath φ 4mm, between 91 °～90 ° of the valve sealing band angles that cooperates with inlet and outlet gate seat seal band, the intake valve umbrella directly is φ 20mm, the exhaust valve umbrella directly is φ 16.5mm;

The design of distribution cam axle type shape line, distribution rocking arm ratio is 24: 17; Port timing: the intake valve angle of advanced opening is 10 degree, and the late angle of closing of intake valve is 15 degree, and the exhaust valve angle of advanced opening is 25 degree, and angle, exhaust valve pass in evening is 1.5 degree;

To valve, valve spring, cotter seat, piston, wrist pin light-weight design, the same parts quality of the former 139QMB of total mass ratio of these parts reduces by 25%;

Piston mass reduces by 20% than original, and piston pin hole is φ 10mm, and piston pin external diameter is φ 10mm, and the connecting rod small end aperture is φ 10mm; Piston one ring adopts twist type ring, and assembling back distortion angle is 20 °, and piston one ring thickness is 0.8mm, and piston two ring thicknesses are 0.8mm, and oil ring thickness is for being 1.5mm;

Empty filter coupling PD20J Carburetor; Described empty filter, its housing and cap are triangle, and element kit is arranged between housing and the cap inside, form the main chamber of sky filter in case side, form the secondary chamber of sky filter in the cap side; Be provided with cylinder head secondary air compensating connecting tube in main chamber upper front end, be provided with crankcase gas blowby connecting tube in its underpart, crankcase gas blowby connecting tube is connected with crankcase gas blowby condensation chamber, and the opening of crankcase gas blowby condensation chamber communicates with main chamber; Minimum point place in main chamber lower rear is provided with oil-collecting/water pipe.

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