CN203547906U

CN203547906U - Two-stroke engine

Info

Publication number: CN203547906U
Application number: CN201320734624.7U
Authority: CN
Inventors: 王军; 汤治国; 山本茂生
Original assignee: Joy Days Power Machinery Research And Development (linyi) Co Ltd
Current assignee: Joy Days Power Machinery Research And Development (linyi) Co Ltd
Priority date: 2013-11-20
Filing date: 2013-11-20
Publication date: 2014-04-16
Anticipated expiration: 2023-11-20

Abstract

The utility model discloses a two-stroke engine, and relates to the technical field of engines. The two-stroke engine comprises a cylinder with an air inlet and an air outlet, a piston, a connection rod, a combustion acting chamber, a crankshaft chamber and at least a pair of scavenging passages. The piston and the connection rod are arranged in the cylinder and can move, the combustion acting chamber is defined by the cylinder above the piston and a part of a cylinder barrel, the crankshaft chamber is arranged below the piston, and the scavenging passages are communicated with the crankshaft chamber and the combustion acting chamber. Each scavenging passage comprises at least one inlet portion and an outlet portion, and the inlet portions and the outlet portions of the scavenging passages are controlled to be opened and closed through moving of the piston. In addition, a ventilation chamber is arranged on the side wall periphery defined by the cylinder barrel, and the ventilation chamber is a part of the scavenging passages. Compared with the prior art, the two-stroke engine has the advantages of reducing loss of fresh gas mixture, improving scavenging efficiency, and lowering the emission value of unburned HC.

Description

A kind of two stroke engine

technical field

The utility model relates to two stroke engine technical field, especially relates to a kind of method by piston movement and control scavenging and import to the two stroke engine of cylinder.

Background technique

At present, already present two stroke engine scavenging system, comprising: cylinder, piston, work by combustion chamber, crankshaft room, wherein in cylinder, be provided with suction port, relief opening and scavenging port, and all by the control of piston, it opens or closes these gas ports; A work cycle of two stroke engine comprises: air inlet, compression, work by combustion, exhaust, a work cycle of two stroke engine is to be completed by two strokes of piston, in this one-stroke of the scavenging of wherein simultaneously carrying out in air inlet and exhaust, gas and the waste gas of fresh charge are easy to blending, cause the coefficient of residual gas in cylinder larger, between scavenging period, have more fresh charge directly to get rid of, cause unburned HC discharge higher, scavenging efficiency is lower simultaneously.Be different from two stroke engine, the scavenging process of four stroke engine is to carry out in two different piston strokes, and the chance of fresh charge and waste gas blending is less, scavenging at the end in cylinder coefficient of residual gas less, scavenging efficiency is higher.

But volume is little, lightweight, structure is relatively simple because this two stroke engine has, the advantage that power per liter is large, therefore be conventionally useful on the miniature power units such as motorcycle, motor boat, atomizing sprayer and mowing machine.

In the process that this two stroke engine is moved to top dead center by lower dead center at piston, the mixed gas of certain air fuel ratio is inhaled into crankshaft room from suction port, as above stated, this one stroke is carrying out the work cycle of compression, work by combustion simultaneously, in the process of work by combustion, piston is moved to lower dead center by top dead center, the later stage of expanding in acting, relief opening is opened in advance, the process that starts to take a breath, is divided into the gas exchange process of two stroke engine free exhaust stage, scavenging period and exhaust phase three phases later conventionally.In this complicated gas exchange process, the entering to overlap of the discharge of waste gas and fresh charge carried out, especially work as the moment that descent of piston scavenging port is opened, now the area of exhaust open is very large, pressure in cylinder declines rapidly, fresh charge in the process of descent of piston in compressed crankshaft room imports in cylinder, and further scan out the waste gas in cylinder, until till piston is up to scavenging port and closed by lower dead center, this one-phase scavenging and exhaust are carried out simultaneously, therefore within this stage, quite a few unburned HC discharges cylinder, cause the loss of unburned fuel and the rising (with reference to accompanying drawing 1) of HC discharge.

Model utility content

For overcoming the technological deficiency that in prior art, two stroke engine exists, that is: at scavenging period, just controlled fresh charge and entered into by scavenging port the moment that cylinder interior is opened or closed, scavenge flow be cannot accurately control and the time phase of scavenging air belt ingress and the pressure of scavenge flow and flow velocity entered into, thereby cannot better control the escape of fresh charge and the discharge of waste gas, thereby cause the loss of fuel and the rising of unburned HC discharge.

An object of the present utility model designs a kind of two stroke engine exactly, by least having an entrance part and an export department in the scavenging channel setting that is communicated with crankshaft room and work by combustion chamber.Wherein, the entrance part of described scavenging path and export department control it by the movement of described piston to open and close, and to improve the scavenging efficiency of motor, thereby have significantly reduced coefficient of residual gas in cylinder and the discharge value of unburned HC compound.

It is as follows that the utility model solves the technological scheme that its technical problem adopts:

A kind of two stroke engine of the utility model, comprise the cylinder that is provided with suction port and relief opening, be arranged on movably piston and connecting rod in cylinder, one is positioned at work by combustion chamber that piston top and cylinder barrier part part surround and one and is positioned at the crankshaft room of piston below, also has the scavenging path of a pair of connection crankshaft room and work by combustion chamber at least, described scavenging path at least has an entrance part and an export department, the entrance part of described scavenging path and export department control it by the movement of piston to open and close, in addition, the side wall perimeter surrounding at cylinder barrel is provided with air-exchanging chamber, described air-exchanging chamber forms a part for scavenging path.

The switching of described scavenging path middle outlet portion and entrance part realizes by the height of control piston.

The entrance part that at least one through hole is communicated with crankshaft room and scavenging path is set on the surface of the described wrist pin that is positioned at piston pin hole, thereby realizes the switching of controlling scavenging path entrance by the movement of piston.

The a pair of main scavenging path and a pair of secondary scavenging path that are communicated with crankshaft room and work by combustion chamber are set on described cylinder, in described major and minor scavenging path, be respectively arranged with a pair of entrance part and a pair of export department, on the surface of described piston, be respectively arranged with a pair of first passage and a pair of second channel.

With respect to the axial direction of cylinder barrel, the apical side height of the export department of described scavenging path is higher than the apical side height of described relief opening.

The utility model is owing to adopting above structure, by the motion of piston, control the entrance part that is arranged in scavenging path and the opening and closing of export department, thereby realize the accurate scavenge flow of controlling and enter into the time phase of scavenging air belt ingress and the pressure of scavenge flow and flow velocity, thereby in gas exchange process, realized the layered scavenging of part, reduced the loss of incoming mixture, improve scavenging efficiency, reduced the discharge value of unburned HC.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of background technique in the utility model;

Fig. 2 is the utility model the first embodiment's principles of construction figure to Fig. 4;

Fig. 5 is the second embodiment's of adopting in the utility model longitudinal structure figure;

Fig. 6 is the longitudinal structure figure of piston and wrist pin thereof combination in Fig. 5;

Fig. 7 is the 3rd embodiment's that adopts in the utility model longitudinal structure figure;

Fig. 8 is the longitudinal structure figure of cylinder in Fig. 7;

Fig. 9 is the sectional drawing along I-I line is done in Fig. 8;

Figure 10 is the sectional drawing along II-II line is done in Fig. 8;

Figure 11 is the tectonic maps of piston in Fig. 8;

Figure 12 is the sectional drawing along I-I line is done in Figure 11;

Figure 13, Figure 14 are the first embodiment in the utility model, the second embodiment's schematic diagram;

Figure 15, Figure 16 are the schematic diagram of three embodiments in the utility model.

Embodiment

Below in conjunction with accompanying drawing, the utility model is elaborated:

As shown in drawings, in figure: 1, one embodiment's two stroke engine, 2, another embodiment's two stroke engine, 10, right hand crankshaft casing, 11, left hand crankshaft casing, 12, crankcase body pad, 13, through hole bolt, 14, connecting rod, 15, right hand crankshaft, 16, left hand crankshaft, 17, crankshaft room, 18, cylinder, 19, piston, 19 a, the first passage arranging on piston, 19 b, the second channel arranging on piston, 20, spark plug, 21, work by combustion chamber, 22, relief opening, 23, scavenge trunk, 23 a, the export department of scavenge trunk, 23 b, the entrance part of scavenge trunk, 24, cylinder sidewall, 25, air-exchanging chamber cover plate, 26, air-exchanging chamber, 27, wrist pin, 28, piston pin boss, 33, the secondary scavenge trunk arranging on cylinder, 33a, the export department of the secondary scavenge trunk arranging on cylinder, 33b, the entrance part of the secondary scavenge trunk arranging on cylinder, 34, the main scavenge trunk arranging on cylinder, 34a, the export department of the main scavenge trunk arranging on cylinder, 34b, the entrance part of the main scavenge trunk arranging on cylinder, 35, right side air-exchanging chamber cover plate, 36 left side air-exchanging chamber cover plates.

A kind of two stroke engine of the utility model, it comprises: cylinder, wherein be provided with suction port and relief opening, and be movably arranged on piston and the connecting rod in cylinder, piston is connected by wrist pin with connecting rod, one is positioned at work by combustion chamber that piston top and cylinder barrier part part surround and one and is positioned at the crankshaft room of piston below, has the scavenging path of a pair of connection crankshaft room and work by combustion chamber at least, the scavenging path that is communicated with crankshaft room and work by combustion chamber at least has an entrance part and an export department, wherein, the entrance part and the export department that are arranged on the scavenging path on the sidewall being surrounded by cylinder barrel control it by the movement of piston to open and close, in addition, the side wall perimeter surrounding at cylinder barrel is provided with air-exchanging chamber, described air-exchanging chamber is a part that forms scavenging path.

In technique scheme, the first embodiment realizes by the height of control piston the switching of controlling scavenging path middle outlet portion and entrance part.

In technique scheme, the second embodiment is the entrance part that form that at least one through hole is set on the surface of the wrist pin by being positioned at piston pin hole is communicated with crankshaft room and scavenging path, thereby the switching of scavenging path entrance is controlled in realization by the movement of piston.

In technique scheme, the 3rd embodiment arranges a pair of main scavenging path and a pair of secondary scavenging path that are communicated with crankshaft room and work by combustion chamber on cylinder, in major and minor scavenging path, have respectively a pair of entrance part and a pair of export department above, and on the surface of piston, be respectively arranged with a pair of first passage and a pair of second channel.

The a certain moment that first passage described above moves up and down at piston is communicated with described crankshaft room and the entrance part of secondary scavenging path, the a certain moment that second channel moves up and down at piston is communicated with described crankshaft room and the entrance part of main scavenging path, in during piston moves towards lower dead center, the export department of secondary scavenging path opens in advance with respect to the export department of main scavenging path, and the time that piston first passage is communicated with secondary scavenging path entrance part is simultaneously communicated with the time of main scavenging path entrance part in advance in piston second channel.

In addition, at piston towards in during lower dead center operation, the time that the secondary scavenging path of described piston first passage control entrance part is closed will be a little earlier in the time of stating the main scavenging path of piston second channel control entrance part and closing.

In above-mentioned the first embodiment, the second embodiment and the 3rd embodiment, with respect to the axial direction of cylinder barrel, the apical side height of the export department of described scavenging path can be set to the apical side height higher than described relief opening.

Claims

1. a two stroke engine, it is characterized in that: comprise the cylinder that is provided with suction port and relief opening, be arranged on movably piston and connecting rod in cylinder, one is positioned at work by combustion chamber that piston top and cylinder barrier part part surround and one and is positioned at the crankshaft room of piston below, also has the scavenging path of a pair of connection crankshaft room and work by combustion chamber at least, described scavenging path at least has an entrance part and an export department, the entrance part of described scavenging path and export department control it by the movement of piston to open and close, in addition, the side wall perimeter surrounding at cylinder barrel is provided with air-exchanging chamber, described air-exchanging chamber forms a part for scavenging path.

2. two stroke engine according to claim 1, is characterized in that: the switching of described scavenging path middle outlet portion and entrance part realizes by the height of control piston.

3. two stroke engine according to claim 1, it is characterized in that: the entrance part that at least one through hole is communicated with crankshaft room and scavenging path is set on the surface of the described wrist pin that is positioned at piston pin hole, thereby realizes the switching of controlling scavenging path entrance by the movement of piston.

4. two stroke engine according to claim 1, it is characterized in that: a pair of main scavenging path and a pair of secondary scavenging path that are communicated with crankshaft room and work by combustion chamber are set on described cylinder, in described major and minor scavenging path, be respectively arranged with a pair of entrance part and a pair of export department, on the surface of described piston, be respectively arranged with a pair of first passage and a pair of second channel.

5. according to the two stroke engine described in claim 1,2,3 or 4, it is characterized in that: with respect to the axial direction of cylinder barrel, the apical side height of the export department of described scavenging path is higher than the apical side height of described relief opening.