CN110778393A

CN110778393A - Auxiliary air pump of direct injection engine in ignition type low-pressure cylinder

Info

Publication number: CN110778393A
Application number: CN201910945427.1A
Authority: CN
Inventors: 黎艺文; 邓宇; 汤镇徽
Original assignee: Guangxi Qingxin Power Technology Co Ltd
Current assignee: Guangxi Qingxin Power Technology Co Ltd
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2020-02-11

Abstract

The invention relates to the technical field of engines, and particularly discloses an auxiliary air pump of a spark-ignition type direct injection engine in a low-pressure cylinder, which comprises: the piston ring is connected with the piston pin, the piston rod, the eccentric wheel, the bearing, the spring, the plate valve and the pressure relief valve assembly. According to the invention, the eccentric wheel is directly driven to rotate by the crankshaft of the engine, and the connecting rod is driven to push the piston to reciprocate, so that the phase relation between the crankshaft and the eccentric wheel is more accurate, the air inlet time is accurate, the structure of the engine is simplified, and the weight is reduced; the flap valve and the spring can control the inflation efficiency, and the lubricating oil in the oil storage tank can increase the gas passing viscosity at the gap of the flap valve, so that the gas is prevented from being sucked back into the cylinder when the piston moves downwards, the gas inlet efficiency is improved, and the pressure loss is reduced; the pressure relief valve assembly can balance overlarge pressure in the air cylinder, and the stability of the gas flow in the air pump is improved.

Description

Auxiliary air pump of direct injection engine in ignition type low-pressure cylinder

Technical Field

The invention belongs to the technical field of engines, and particularly relates to an auxiliary air pump of a spark-ignition type direct injection engine in a low-pressure cylinder.

Background

Heavy oil has the characteristics of high viscosity, high flash point and difficult volatilization, and is safer and more reliable in the transportation and storage processes, so the heavy oil is favored in the fields of military, ships and aircraft engines, particularly has great development prospect in the field of small unmanned aerial vehicle engines, the heavy oil engine is listed as one of important development targets of the unmanned aerial vehicle technology in the United states of America in the unmanned aerial vehicle development route diagram (2005-laid 2030), and the research and development work of the heavy oil engine is actively promoted in various aspects of China.

Because heavy oil has high viscosity and thus poor atomization and combustion performance, the combustion requirements of a heavy oil engine are difficult to achieve by normal compression ignition or ignition means of a traditional engine, and therefore the combustion requirements of the heavy oil engine are generally achieved by means of fine atomization, heavy oil auxiliary preheating, improvement of a combustion chamber structure and the like. The fine atomization is realized by improving the structure of the oil sprayer and accurately controlling the relationship between the injection quantity of the atomized gas and an injection node, and the relationship between the injection quantity of the heavy oil and the phase of the injection node and the engine crankshaft; and for small unmanned aerial vehicle, still have the lightweight to the engine, the requirement of easy maintenance.

The atomized auxiliary gas is provided by an air compression pump on the engine, the existing air compression pump for the engine is mostly a plunger crankshaft type air pump, and because a gear set at the crankshaft end of the engine drives a crankshaft in the air pump to rotate, the accurate control of the ventilation volume and the ventilation node of the air pump through the phase of the crankshaft of the engine is difficult to realize; moreover, because of excessive parts and complex structure, errors are superimposed, and the total weight of the engine and the maintenance difficulty are increased.

Disclosure of Invention

The invention aims to provide an auxiliary air pump of a direct injection engine in a spark-ignition low-pressure cylinder, so that the defects of poor control difficulty, large error, complex structure, heavy weight and difficult maintenance of the ventilation volume, the ventilation node and the engine crankshaft phase of the conventional air pump are overcome.

In order to achieve the above object, the present invention provides an auxiliary air pump for a spark-ignition low-cylinder direct injection engine, comprising: the shell consists of an upper shell and a lower shell, the lower shell is provided with two spindle holes aligned with each other and a plurality of air inlet holes communicated with the inner cavity of the lower shell, and the top of the upper shell is provided with an air outlet hole communicated with the inner cavity of the upper shell; the cylinder is arranged in the inner cavity of the lower shell and comprises a piston hole penetrating through the cylinder, a first concave spigot is arranged at the top of the piston hole, an oil storage tank is arranged on a stepped surface between the first concave spigot and the piston hole, and a plurality of gas leading-in holes leading to the outside of the cylinder are arranged on the side wall of the piston hole; the piston is arranged in the piston hole, the top of the piston faces the first concave spigot, and a piston pin is arranged on the piston; the small end of the connecting rod is sleeved on the piston pin, and the large end of the connecting rod is provided with a connecting rod shaft hole; the eccentric wheel is sleeved in the connecting rod shaft hole through a first bearing, an eccentric hole is formed in the eccentric wheel, one end shaft of the engine crankshaft penetrates through the eccentric hole and is fixed with the eccentric wheel, and the end shaft further penetrates through the two main shaft holes in a rotatable mode and extends outwards; a flap valve slidably disposed in the first female spigot, the flap valve having an outer diameter greater than the diameter of the piston bore, a first spring disposed between the flap valve and the upper housing; and one end of the pressure relief valve assembly is communicated with the inner cavity of the upper shell through an upper pressure relief pipeline, and the other end of the pressure relief valve assembly is communicated with the inner cavity of the lower shell through a lower pressure relief pipeline.

Preferably, in the above technical scheme, the upper pressure relief pipeline is arranged in the upper housing, and the lower pressure relief pipeline is arranged in the lower housing.

Preferably, in the above technical solution, the relief valve assembly includes: the pressure relief valve cavity is arranged in the lower shell, the bottom of the pressure relief valve cavity is communicated with the lower pressure relief pipeline, and a cavity opening of the pressure relief valve cavity is arranged on the top surface of the lower shell and corresponds to the other end of the upper pressure relief pipeline; the pressure relief valve seat is arranged at the orifice of the pressure relief valve cavity, a pressure relief hole penetrates through the center of the pressure relief valve seat, and a conical hole is arranged below the pressure relief hole; and the valve rod is arranged in the pressure relief valve cavity, a steel ball is arranged at one end of the valve rod, and a second spring is arranged between the other end of the valve rod and the bottom of the pressure relief valve cavity.

Preferably, in the above technical scheme, a second concave spigot is arranged at the orifice of the inner cavity of the lower shell, and a convex spigot matched with the second concave spigot is arranged at the orifice of the inner cavity of the upper shell.

Preferably, in the above technical scheme, the outer diameter of the cylinder is smaller than the diameter of the inner cavity of the lower housing, the plurality of boss rings are circumferentially arranged below the outer side surface of the cylinder, the thrust shoulder is arranged on the outer side surface of the cylinder and above the gas introduction hole, the outer diameter of the thrust shoulder is matched with the second concave spigot, and the upper thrust surface of the thrust shoulder is provided with a first O-ring.

Preferably, in the above technical solution, the small end of the connecting rod is sleeved on the piston pin through a second bearing.

Preferably, in the above technical solution, the piston is provided with a piston ring, and the piston ring is located near the top of the piston.

Preferably, in the above technical scheme, a second O-ring is arranged at a cavity opening of the pressure relief valve cavity.

Preferably, in the above technical solution, the thickness of the flap valve is not more than 1.5 mm.

Preferably, in the technical scheme, the width of the oil storage tank is 0.3-3 mm, and the height of the oil storage tank is 0.3-3 mm.

Preferably, in the above technical solution, the cylinder is provided with a gas introduction hole, and the shape of the gas introduction hole is a circular hole, a square hole, or an ellipse.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention directly drives the connecting rod to push the piston to reciprocate through the rotation of the eccentric wheel on the end shaft of the crankshaft of the engine, thereby not only providing a power source of the air pump, but also ensuring that the phase relation between the crankshaft and the eccentric wheel is more accurate and direct, the driving efficiency is higher, and the weight of the engine is reduced through simplifying the structure.

2. The invention accurately controls the opening and closing time of the flap valve by adjusting the rigidity of the first spring, and ensures the pressure and the throughput of gas.

3. According to the invention, the oil storage tank is designed between the flap valve and the cylinder, and oil can be contained when the flap valve is opened, so that the passing viscosity of gas passing through a gap of the flap valve is increased, and the gas is prevented from being sucked back into the cylinder when the piston moves downwards.

4. According to the invention, the pressure relief valve assembly is used for ensuring that when the gas pressure in the cylinder is overlarge, the overlarge pressure in the cylinder can be balanced, and redundant gas is discharged into the inner cavity of the shell, so that the stability of the gas flow in the gas pump is ensured.

Drawings

Fig. 1 is a structural diagram of an auxiliary air pump of a spark-ignition low-cylinder direct injection engine.

Fig. 2 is a partial enlarged view i of fig. 1.

FIG. 3 is a cross-sectional view of an upper housing of an auxiliary air pump of a spark-ignited low cylinder direct injection engine.

FIG. 4 is a block diagram of a cylinder of an auxiliary air pump of a spark-ignited low-cylinder direct injection engine.

FIG. 5 is a block diagram of a connecting rod of an auxiliary air pump of a spark-ignited low cylinder direct injection engine.

FIG. 6 is a cross-sectional view of an eccentric wheel of an auxiliary air pump of a spark-ignited low-cylinder direct injection engine.

Description of the main reference numerals:

1-housing, 2-cylinder, 3-piston, 4-connecting rod, 5-eccentric wheel, 6-flap valve, 7-relief valve assembly, 8-first bearing, 9-engine crankshaft, 10-end shaft, 11-first spring, 12-second female spigot, 18-main shaft bearing, 13-male spigot, 14-first O-ring, 15-second bearing, 16-piston ring, 17-second O-ring, 101-upper housing, 102-lower housing, 103-main shaft hole, 104-inlet hole, 105-outlet hole, 21-piston hole, 22-first female spigot, 23-oil storage groove, 24-gas inlet hole, 25-boss, 26-thrust shoulder, 31-piston pin, 41-connecting rod shaft hole, 51-eccentric hole, 71-upper pressure relief pipeline, 72-lower pressure relief pipeline, 73-pressure relief valve cavity, 74-hydraulic valve seat, 75-pressure relief hole, 76-valve rod, 77-steel ball and 78-second spring.

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.

As shown in fig. 1 to 6, the ignition type low in-cylinder direct injection engine auxiliary air pump in the embodiment includes: the hydraulic oil cylinder comprises a shell 1, a cylinder 2, a piston 3, a connecting rod 4, an eccentric wheel 5, a plate valve 6, a pressure relief valve assembly 7, a first bearing 8, an engine crankshaft 9, an end shaft 10, a first spring 11, a second female spigot 12, a main shaft bearing 18, a male spigot 13, a first O-ring 14, a second bearing 15, a piston ring 16, a second O-ring 17, an upper shell 101, a lower shell 102, a main shaft hole 103, an air inlet hole 104, an air outlet hole 105, a piston hole 21, a first female spigot 22, an oil storage groove 23, an air inlet hole 24, a boss 25, a thrust shoulder 26, a piston pin 31, a connecting rod shaft hole 41, an eccentric hole 51, an upper pressure relief pipeline 71, a lower pressure relief pipeline 72, a pressure relief valve cavity 73, a hydraulic valve seat 74, a pressure relief hole 75, a valve rod 76, a steel ball. The shell 1 is divided into an upper shell 101 and a lower shell 102, inner cavities are formed in the two shells, and the upper shell 101 and the lower shell 102 are fixedly connected through bolts; an air outlet hole 105 communicated with the inner cavity of the upper shell 101 is formed in the center of the top of the upper shell 101, a matching surface matched with the lower shell 102 is formed in the bottom of the upper shell, a male end 13 is formed in the cavity opening of the inner cavity of the upper shell 101 along the contour of the cavity opening, and the male end 13 protrudes out of the matching surface of the upper shell 101; the upper part of the lower shell 102 is a matching surface which is matched with the upper shell 101, the cavity opening of the inner cavity of the lower shell is arranged on the matching surface, a second concave spigot 12 is arranged at the cavity opening of the lower shell 102 along the contour of the cavity opening, the spigot surface of the second concave spigot 12 is lower than the matching surface of the lower shell 102, the second concave spigot 12 and the convex spigot 13 can be matched with each other, two opposite side surfaces of the lower shell 102 are provided with two mutually aligned (coaxial) spindle holes 103, and one side surface of the lower shell 102 is provided with at least two air inlet holes 104 which are communicated with the inner cavity of the lower shell 102. The cylinder 2 is embedded in the inner cavity of the lower shell 102, the center of the cylinder 2 is provided with a piston hole 21 penetrating through the whole cylinder, one end of the piston hole 21 is provided with a first concave spigot 22, an oil storage tank 23 is arranged on the step surface between the first concave spigot 22 and the piston hole 21 along the contour of the piston hole 21, the width of the oil storage tank 23 is 0.3-3 mm, and the height of the oil storage tank is 0.3-3 mm; a plurality of gas introduction holes 24 are circumferentially formed in the side wall of the cylinder 2, the gas introduction holes are circular, square and elliptical, the piston hole 21 is communicated with the outside of the cylinder 2 through the gas introduction holes 24, and the number of the gas introduction holes 24 is 3-12; the diameter of the outer side of the cylinder 2 is smaller than that of the inner cavity of the lower shell 102, 4 bosses 25 are circumferentially fixed below the outer side surface of the cylinder 2, and the height of each boss 25 can just support and fix the cylinder 2 in the inner cavity of the lower shell 102 and form tight fit; a thrust shoulder 26 is fixed on the outer side surface of the cylinder 2, protrudes out of the outer side surface of the cylinder 2 and is positioned above the gas inlet hole 24, the outer diameter of the thrust shoulder 26 is matched with the caliber of the second female spigot 12, and a first O-shaped ring 14 is arranged on the upper thrust surface of the thrust shoulder 26. The piston 3 is sleeved in a piston hole 21 of the cylinder 2, the top of the piston faces the first female spigot 22, the piston ring 16 is installed on the side surface of the piston, the installation position of the piston ring 16 is close to the top of the piston 3, and a piston pin 31 is installed in the piston 3. The small end of the connecting rod 4 is sleeved on the piston pin 31 through the second bearing 15, the large end of the connecting rod 4 is provided with a connecting rod shaft hole 41, the connecting rod shaft hole 41 is internally sleeved with the first bearing 8, the inner hole of the first bearing 8 is sleeved on the excircle of the eccentric wheel 5, the middle of the eccentric wheel 5 is provided with an eccentric hole 51, the axis of the eccentric wheel is parallel to the axis of the excircle of the eccentric wheel 5, and the two axes are spaced by a certain distance. The length of an end shaft 10 at one side of an engine crankshaft 9 is lengthened, and the end shaft respectively penetrates through a main shaft hole 103, an eccentric hole 51 and another main shaft hole 103 from one side of a lower shell 102 and then penetrates out from the other side of the lower shell 102; the end shaft 10 is rotatably mounted in the spindle hole 103 by means of a spindle bearing 18, and the end shaft 10 fixes the eccentric 5 by means of a shaft key or a tight fit with the eccentric hole 51. The diameter of the flap valve 6 is slightly smaller than that of the first concave spigot 22 and larger than that of the piston hole 21, the thickness of the flap valve 6 is not more than 1.5mm, and the flap valve 6 is arranged in the first concave spigot 22 and can slide up and down along the first concave spigot 22; a first spring 11 is arranged between the flap valve 6 and the top of the inner cavity of the upper shell 101, and the air outlet hole 105 is opposite to the middle of the first spring 11. An upper pressure relief pipeline 71 is arranged in the shell wall of the upper shell 101, one end of the upper pressure relief pipeline is communicated with the inner cavity of the upper shell 101, and the other end of the upper pressure relief pipeline extends out of the mounting surface between the upper shell 101 and the lower shell 102; a lower pressure relief pipeline 72 is opened in the wall of the lower casing 102, one end of which is communicated with the inner cavity of the lower casing 102, and the other end of which is connected with the pressure relief valve assembly 7.

With continued reference to fig. 2, the relief valve assembly 7 includes a relief valve cavity 73 disposed in the side wall of the lower casing 102, the bottom of the relief valve cavity 73 is communicated with the other end of the lower relief pipe 72, and the orifice of the relief valve cavity 73 is disposed on the assembly plane between the lower casing 102 and the upper casing 101 and aligned with the pipe orifice of the upper relief pipe 71; a pressure relief valve seat 74 is embedded at the orifice of the pressure relief valve cavity 73, a pressure relief hole 75 is formed in the center of the pressure relief valve seat 74 in a penetrating mode, a conical hole is formed below the pressure relief hole 75, and the top surface of the pressure relief valve seat 74 is level with the matching surfaces of the lower shell 102 and the upper shell 101; the valve rod 76 is arranged in the pressure relief valve cavity 73, one end of the valve rod is provided with a steel ball 77, the other end of the valve rod is provided with a second spring 78 between the bottom of the pressure relief valve cavity 73, and the steel ball 77 can be tightly propped against a conical hole at the bottom of the pressure relief valve seat 74 through the tension force of the second spring 78; a second O-ring 17 is mounted on the top surface of the relief valve seat 74 at the orifice of the relief hole 75.

The working principle of the auxiliary air pump of the spark-ignition type low-pressure in-cylinder direct injection engine of the embodiment is further described below, so that a person skilled in the art can more clearly understand the technical scheme:

1. when the engine crankshaft 9 rotates, the end shaft 10 can drive the eccentric wheel 5 to rotate, and due to the characteristics of the eccentric wheel 5, when the engine crankshaft 9 rotates, the connecting rod 4 can be directly driven to drive the piston 3 to reciprocate up and down in the cylinder 2; by varying the angle of mounting of the eccentric 5, the phase difference between the eccentric 5 and the crankshaft can be determined directly, thereby controlling the timing of the movement of the piston 3 more accurately.

2. When the piston 3 moves downwards, the air outside the air pump is sucked into the cylinder 2 through the air inlet hole 104, the inner cavity of the lower shell 102 and the air introducing hole 24 in sequence; when the piston 3 moves upwards, the gas in the cylinder 2 starts to be compressed, and when the piston 3 moves to the top dead center, the pressure generated by the gas in the cylinder can overcome the pressure of the first spring 11 to push the flap valve 6 open, and the gas in the cylinder 2 is discharged as auxiliary gas to a fuel injector of an engine through the gas outlet hole 105 to be mixed with heavy oil.

3. When the piston 3 moves downwards from the top dead center again, the first spring 11 pushes the flap valve 6 downwards again due to the reduction of the pressure in the cylinder 2, and at the moment, the lubricating oil in the oil storage tank 23 is adhered to the periphery of the flap valve 6, and the lubricating oil can fill the gap between the outer side of the flap valve 6 and the hole wall of the first female stop 22, so that the passing viscosity of the gas between the gap is increased, and the gas exhausted is prevented from being sucked back when the piston 3 moves downwards, and the gas pressure and the flow of the auxiliary gas of the injector are prevented from being reduced.

4. The gas valve is also provided with a pressure relief valve assembly 7, when the piston 3 compresses gas, if the pressure in the cylinder 2 is too high, the gas can overcome the elastic force of the second spring 78 and push the steel ball 77 open, so that the gas returns to the inner cavity of the lower shell 102, and the excessive gas pressure is balanced.

In conclusion, the eccentric wheel is directly driven to rotate by the crankshaft of the engine, and the connecting rod is driven to push the piston to reciprocate, so that the phase relation between the crankshaft and the eccentric wheel is more accurate, the starting efficiency is high, the structure of the engine is simplified, and the weight is reduced; the sheet valve can control the ventilation time of ventilation, and lubricating oil in the oil storage tank can increase the gas passing viscosity at the gap of the sheet valve, so that the gas is sucked back into the cylinder when the piston moves downwards, the gas inlet efficiency is improved, and the pressure loss is reduced; the pressure relief valve assembly can balance overlarge pressure in the air cylinder, and the stability of the gas flow in the air pump is improved.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.

Claims

1. An auxiliary air pump of a spark-ignition type low-cylinder direct injection engine is characterized by comprising:

the air conditioner comprises a shell (1) and a control device, wherein the shell (1) consists of an upper shell (101) and a lower shell (102), two spindle holes (103) which are aligned with each other and a plurality of air inlet holes (104) communicated with the inner cavity of the lower shell (102) are formed in the lower shell (102), and an air outlet hole (105) communicated with the inner cavity of the upper shell (101) is formed in the top of the upper shell (101);

the cylinder (2) is arranged in the inner cavity of the lower shell (12) and comprises a piston hole (21) penetrating through the cylinder (2), a first concave spigot (22) is arranged at the top of the piston hole (21), an oil storage tank (23) is arranged on a stepped surface between the first concave spigot (22) and the piston hole (21), and a plurality of gas leading-in holes (24) leading to the interior of the cylinder (2) are formed in the side wall of the piston hole (21);

the piston (3) is arranged in the cylinder (2), the top of the piston faces the first female spigot (22), and a piston pin (31) and a piston ring (16) are arranged on the piston (3);

the small end of the connecting rod (4) is sleeved on the piston pin (31), and the large end of the connecting rod is provided with a connecting rod shaft hole (41);

the eccentric wheel (5) is sleeved in the connecting rod shaft hole (41) through a first bearing (8), an eccentric hole (51) is formed in the eccentric wheel (5), one end shaft (10) of an engine crankshaft (9) penetrates through the eccentric hole (51) and is fixed with the eccentric wheel (5), and the end shaft (10) penetrates through the two main shaft holes (103) in a rotatable mode and extends outwards;

a flap valve (6) slidably provided in the first female spigot (22), an outer diameter of the flap valve (6) being larger than a diameter of the piston bore (21), a first spring (11) being provided between the flap valve (6) and the upper housing (101);

one end of the pressure relief valve assembly (7) is communicated with the inner cavity of the upper shell (101) through an upper pressure relief pipeline (71), and the other end of the pressure relief valve assembly (7) is communicated with the inner cavity of the lower shell (102) through a lower pressure relief pipeline (72).

2. The spark-ignition low-cylinder direct injection engine auxiliary air pump according to claim 1, characterized in that the upper pressure relief duct (71) is provided in the upper housing (101) and the lower pressure relief duct (72) is provided in the lower housing (102).

3. A spark-ignition, low-cylinder direct injection engine auxiliary air pump according to claim 1, characterized in that said pressure relief valve assembly (7) comprises:

the pressure relief valve cavity (73) is arranged in the lower shell (102), the bottom of the pressure relief valve cavity (73) is communicated with the lower pressure relief pipeline (72), and a cavity opening of the pressure relief valve cavity (73) is arranged on the top surface of the lower shell (102) and corresponds to the other end of the upper pressure relief pipeline (71) in the axial direction;

the pressure relief valve seat (74) is arranged at the opening of the pressure relief valve cavity (73), a pressure relief hole (75) is formed in the center of the pressure relief valve seat (74) in a penetrating mode, and a conical hole is formed below the pressure relief hole (75);

and the valve rod (76) is arranged in the pressure relief valve cavity (73), one end of the valve rod (76) is provided with a steel ball (77), and a second spring (78) is arranged between the other end of the valve rod (76) and the bottom of the pressure relief valve cavity (73).

4. The auxiliary air pump of the spark-ignition low-cylinder direct injection engine according to claim 1, wherein a second female spigot (12) is provided at the mouth of the inner cavity of the lower housing (102), and a male spigot (13) adapted to the second female spigot (12) is provided at the mouth of the inner cavity of the upper housing (101).

5. The spark-ignition low-cylinder-internal-injection engine auxiliary air pump according to claim 1, wherein an outer diameter of the cylinder (2) is smaller than an inner cavity diameter of the lower housing (102), a plurality of bosses (25) are circumferentially arranged below an outer side surface of the cylinder (2), a thrust shoulder (26) is arranged on the outer side surface of the cylinder (2) and above the gas introduction hole (24), the outer diameter of the thrust shoulder (26) is matched with the second female spigot (12), and a first O-ring (14) is arranged on an upper thrust surface of the thrust shoulder (26).

6. The spark-ignition low-cylinder direct injection engine auxiliary air pump according to claim 1, characterized in that the small end of the connecting rod (4) is sleeved on the piston pin (31) through a second bearing (15).

7. The spark-ignition low-cylinder direct injection engine auxiliary air pump according to claim 1, characterized in that piston rings (16) are provided on the piston (3), and the piston rings (16) are located near the top of the piston (3).

8. The auxiliary air pump of the spark-ignition low-cylinder-internal-injection engine according to claim 2, characterized in that a second O-ring (17) is arranged at the opening of the pressure relief valve cavity (73).

9. The auxiliary air pump of the spark-ignition low-cylinder direct injection engine according to claim 1, wherein the thickness of the plate valve (6) is not more than 1.5mm, the groove width of the oil storage groove (23) is 0.3-3 mm, and the groove height is 0.3-3 mm.

10. The spark-ignition low-cylinder direct injection engine auxiliary air pump according to claim 1, characterized in that the shape of the air introduction hole (24) is a circular hole, a square hole, an ellipse.