CN1282835A

CN1282835A - Scavenge system of 2-stroke engine

Info

Publication number: CN1282835A
Application number: CN99115510A
Authority: CN
Inventors: 李荟敏
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-07-28
Filing date: 1999-07-28
Publication date: 2001-02-07

Abstract

A scavenge system for two-stroke engine features that its scavenge ports are arranged on cylinder sleeve in same rotating direction by tangent mode to make newly filled substance come into cylinder in rotary mode, and an exhaust channel to exhaust port is arranged in central part of piston top so that the new and waste gases are layered in cylindrical or conic mode for full combustion of fuel and full discharge of carbonhydrate.

Description

The scavenging system of two stroke engine

The present invention relates to a kind of scavenging system of two stroke engine, be applicable to the two stroke engine that automobile, motorcycle, light airplane, boats and ships, model plane and mobile power station etc. are used as power, the spark ignition two stroke engine of a piston of particularly every cylinder.

Two stroke engine scavenging system always, the scavenging system of the spark ignition two stroke engine of a piston of particularly every cylinder adopts loop scavenging mode or its modification mostly, and scavenging system directly uses new charge to remove to clean exhaust gas inside cylinder in the loop scavenging mode; In the two stroke engine of opposed piston and overhead exhaust valve, have and use the rotation scavenging system, but their cylinder middle part all can not realize scavenging that their scavenging efficiency is not high yet, and has fuel to run off through the short-circuit loss of scavenging.During engine low load work, cause the water down effect of waste gas to new charge because of mixing with waste gas, motor must use than rich mixture, makes the two stroke engine hydrocarbon emission height of this system of employing, and fuel consumption is also high.And the cylinder fuel injection system that adopts the fresh air scavenging adopts higher scavenging ratio, and does not have the short-circuit loss of fuel, but its price is comparatively expensive.Therefore be necessary to provide the scavenging system of the high and inexpensive two stroke engine of a kind of scavenging efficiency, it has the advantage of the inexpensive and fuel utilization efficiency of mixed gas scavenging system near the fuel injection system of fresh air scavenging.

Task of the present invention provides a kind of scavenging system with higher scavenging efficiency and inexpensive two stroke engine, is applicable to the two stroke engine that automobile, motorcycle, light airplane, boats and ships, model plane and mobile power station etc. are used as power.

Task of the present invention is done in such a manner: the scavenging port on the cylinder of two stroke engine rotates when making new charge sweep cylinder along identical sense of rotation arranged tangential, and piston head middle part then is provided with an air outlet flue and leads to relief opening on the cylinder.During scavenging work, because new charge temperature is more much lower than exhaust gas temperature, thereby density is also much bigger, the big new charge of density occupied the cylinder periphery naturally rotatably when rotation swept cylinder, the waste gas that density is little is then led to the relief opening on the cylinder by the air outlet flue of establishing through the piston head middle part in the middle part of being rushed to and is cleaned, new charge and waste gas present column or taper layering and can not mix very soon, therefore reduced the short-circuit loss of new charge, help ignition because of the charge layering simultaneously, even therefore use two stroke engine of the present invention in low-load work, also can use the mixed gas near equivalent proportion, thereby hydrocarbon emission is low, specific fuel consumption is also low.

The present invention is described in further detail below in conjunction with accompanying drawing: the scavenging system that is illustrated in figure 1 as a single cylinder two-stroke motor, wherein 1 is relief opening, 2 are the tangential scavenging port of rotation, 3 is piston, and 4 is duct formula piston head air outlet flue, and 5 is cylinder, 6 is cylinder head, 7 is spark plug, and 8 is bent axle, and 9 is connecting rod.The arrow indication is an air flow direction among the figure.

Fig. 2 is the sectional view of system shown in Figure 1 on the scavenging port plane, and wherein 1 is relief opening, and 2 are the tangential scavenging port of rotation, and this scavenging port has 7, and 3 is piston, and 4 is duct formula piston head air outlet flue, and 5 is cylinder, and the arrow indication is an air flow direction among the figure.

Being illustrated in figure 3 as duct formula piston head air outlet flue piston, also is the three-view diagram of the piston 3 among Fig. 1, Fig. 2, the relief opening that has a duct formula piston head air outlet flue 4 to lead on the cylinder at the piston head middle part.

As seen when piston 3 moves down, exhaust outlet 1 is opened earlier exhaust in conjunction with Fig. 1, Fig. 2, Fig. 3, Rotary cutting is then opened scavenging to scavenging port 2, because new charge temperature is more much lower than EGT, because of And density is also much bigger, new charge nature when rotary cutting sweeps cylinder 5 to scavenging port 2 that density is big Occupy rotatably the periphery of cylinder 5, the waste gas that density is little is then driven to the middle part and through piston top middle part If culvert type top land exhaust duct 4 lead to exhaust outlet 1 and cleaned, thereby finish to engine Supply with the work of new charge in the cylinder. Compare with existing reverse-flow type and modification thereof, during middle-low load work, The short-circuit loss of scavenging is littler, and the scavenging layering is easier to light, thereby hydrocarbon emission is lower, fuel oil Consumption rate is also low. But during big load operation, power is lower, the piston heat load height.

Fig. 4 is to the modification that Figure 7 shows that four kinds of top land exhaust ducts; Be illustrated in figure 4 as channel-type The three-view diagram of top land exhaust duct piston, wherein 3 is piston, 10 is the exhaust of channel-type top land The road is compared with culvert type top land exhaust duct, and its raceway groove is the top not, thereby has lower heat Load and relatively poor rotation scavenging layering and the short-circuit loss performance of scavenging.

Be illustrated in figure 5 as the three-view diagram of double channel formula piston head air outlet flue piston, wherein 3 is piston, and 10 is channel-type piston head air outlet flue, and certainly, it will be used double gas port cylinder.Similarly two duct formula piston head air outlet flue pistons also can be arranged, do not give unnecessary details.

As Fig. 6 is a kind of reduced form of channel-type piston head air outlet flue, or is referred to as water conservancy diversion ridge chip piston head air outlet flue, and wherein 11 is water conservancy diversion ridge sheet; It also can have two water conservancy diversion ridge chip piston head air outlet flue pistons similarly, and referring to Fig. 7,3,11 indications are identical with Fig. 6 among the figure, do not give unnecessary details.

But the air outlet flue that should point out double channel formula piston head air outlet flue or two water conservancy diversion ridge chip piston head air outlet flue and two duct formula piston head air outlet flues can design lowlyer or be more shallow, help Combustion chamber design and the heat load that reduces piston, just need double gas port and twin exhaust pipes.Because the scavenging layering helps anti-detonation, cause serious detonation so piston head can be established heat insulation layer reduction piston heat flow with the high temperature that reduces piston ring and piston skirt temperature and be unlikely because of the heat insulation layer surface, heat insulation layer spreads all over the piston head surface and comprises the piston head air outlet flue.

Below in conjunction with embodiment the present invention is done further detailed disclosing.

Be illustrated in figure 8 as the scavenging system of single duct formula piston head air outlet flue piston single cylinder two-stroke motor of piston head band heat insulation layer, wherein 1 is relief opening, and 2 are the tangential scavenging port of rotation; 3 is piston; 4 is duct formula piston head air outlet flue, and 5 is cylinder; 6 is cylinder head; 7 is spark plug; 12 is the piston head heat insulation layer.Its working procedure is identical with system shown in Figure 1, does not give unnecessary details.

Fig. 1 and scavenging system shown in Figure 8 all are that example is illustrated with the single cylinder engine, but they all are applicable to multi-cylinder engine bar none, and this is the general character of internal-combustion engine, need not give unnecessary details, only this statement.

Claims

1. the scavenging system of a two stroke engine, the scavenging system of the spark ignition two stroke engine of a piston of particularly every cylinder, form by cylinder, piston etc., be applicable to the two stroke engine that automobile, motorcycle, light airplane, boats and ships, model plane and mobile power station etc. are used as power, it is characterized in that:

1.1 the scavenging port that engine cylinder puts is tangentially arranged by same sense of rotation along cylinder sleeve;

1.2 piston head is provided with the exhaust air flue.

2. according to the scavenging system of the two stroke engine of claim 1 defined, it is characterized in that the exhaust air flue of establishing on the piston head is one of following:

2.1 single air flue of channel-type piston head or double air flue;

2.2 single air flue of duct formula piston head or double air flue;

2.3 single air flue of water conservancy diversion ridge chip piston head or double air flue.

3. according to the scavenging system of the two stroke engine of claim 1 defined, it is characterized in that piston head is provided with the piston head heat insulation layer.