CN215256497U - High compression ratio piston for small gasoline engine - Google Patents

High compression ratio piston for small gasoline engine Download PDF

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Publication number
CN215256497U
CN215256497U CN202121056420.3U CN202121056420U CN215256497U CN 215256497 U CN215256497 U CN 215256497U CN 202121056420 U CN202121056420 U CN 202121056420U CN 215256497 U CN215256497 U CN 215256497U
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China
Prior art keywords
piston
ring groove
groove
compression ratio
gas ring
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Expired - Fee Related
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CN202121056420.3U
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Chinese (zh)
Inventor
齐鹏冲
刘宇恒
张奇
田龙
王忠恕
尤金文
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Jilin University
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Jilin University
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Abstract

The utility model discloses a high compression ratio piston for a small gasoline engine, which overcomes the problems of low compression ratio, long flame propagation distance, long flame propagation time, large heat transfer loss and detonation caused by spontaneous combustion at the final combustion position of the gasoline engine and comprises a head part and a skirt part; the bottom end of the head part is equal to the top end of the skirt part in diameter and is connected into a whole; the head comprises a piston top and a sealing groove; the top of the piston is a cylindrical boss which is 1.7mm higher than the plane of the top of the piston and has a diameter of 55mm, and the cylindrical boss is collinear with the rotary axis of the piston with high compression ratio; the sealing groove comprises a gas ring groove I, a gas ring groove II and an oil ring groove, the width of the gas ring groove I and the width of the gas ring groove II are both 1.2mm, and the width of the oil ring groove is 1.5 mm; the depth of each sealing groove is 2 mm; the first gas ring groove, the second gas ring groove and the oil ring groove are sequentially arranged in parallel from top to bottom, the distance between the upper groove wall of the first gas ring groove and the plane of the top of the piston is 1.2mm, and the width of the groove wall between every two adjacent grooves is 1.2 mm.

Description

High compression ratio piston for small gasoline engine
Technical Field
The utility model relates to an engine cylinder part of engine technical field, more exactly, the utility model relates to a small-size petrol engine is with high compression ratio piston.
Background
The piston is a key part of the engine, and the structure of the piston has great influence on the working state, the service life and the working efficiency of the engine. At present, a concave top piston is generally adopted by a gasoline engine piston. The top shape ensures that the compression ratio of the gasoline engine is lower when the length of the crank connecting rod of the engine is the same; meanwhile, the flame propagation distance is long, the flame propagation time is long, the heat transfer loss is large, and the unburned mixed gas at the final combustion position is easy to further receive the compression and heat radiation effects, so that spontaneous combustion occurs and detonation is generated.
In view of this, the utility model aims at developing a small-size high compression ratio piston for petrol engine, set up the cylindrical boss in the appropriate position, realize the improvement of compression ratio through the piston top surface arch, and then improve the burning, reach the purpose of raising the thermal efficiency; meanwhile, the flame propagation distance is reduced, the flame propagation time is shortened, and the knocking probability of the gasoline engine is reduced; in addition, the engine is required to be convenient to process, reduce friction and mechanical loss, further save energy, improve the working efficiency of the engine and ensure the service life of the engine.
Disclosure of Invention
The utility model aims to solve the technical problem that overcome that prior art exists at the crank connecting rod length of engine the same, the compression ratio of gasoline engine is lower, flame propagation distance is far away simultaneously, flame propagation time is longer, heat transfer loss is great, and be in the last combustion position the not burnt gas mixture easily further receive compression and thermal radiation effect and take place the problem that spontaneous combustion produced the detonation, provide a small-size for gasoline engine high compression ratio piston.
In order to solve the technical problem, the utility model discloses an adopt following technical scheme to realize:
the high-compression-ratio piston for the small gasoline engine comprises a head part and a skirt part; the head part and the skirt part are cylindrical structural parts, the diameter of the bottom end of the head part is equal to that of the top end of the skirt part, and the bottom end of the head part and the top end of the skirt part are connected into a whole;
the head comprises a piston top and a sealing groove;
the top of the piston is a cylindrical boss which is 1.7mm higher than the plane of the top of the piston and has a diameter of 55mm, the cylindrical boss is positioned at the center of the plane of the top end of the piston with high compression ratio, and the cylindrical boss is collinear with the rotation axis of the piston with high compression ratio;
the sealing groove comprises a gas ring groove I, a gas ring groove II and an oil ring groove, the widths of the gas ring groove I and the gas ring groove II are both set to be 1.2mm, and the width of the oil ring groove is 1.5 mm; the depth of each sealing groove is 2 mm; the first gas ring groove, the second gas ring groove and the oil ring groove are sequentially arranged in parallel from top to bottom, the rotation center line of the sealing groove is collinear with the rotation center line of the high-compression-ratio piston, the distance between the upper groove wall of the first gas ring groove and the top plane of the piston is 1.2mm, and the width of the groove wall between every two adjacent grooves is 1.2 mm.
In the technical scheme, the width of the groove wall between two adjacent grooves is 1.2mm, and the width refers to that: the widths between the lower groove wall of the first gas ring groove and the upper groove wall of the second gas ring groove and between the lower groove wall of the second gas ring groove and the upper groove wall of the oil ring groove are both 1.2 mm.
The skirt part in the technical scheme is a cylindrical structural part, the diameter of an inner cavity is 60mm, the depth is 40mm, and part of an arched solid is cut off from the tail of the skirt part along the diameter direction to form 2 symmetrically arranged arc parts and 2 symmetrically arranged end parts, pin holes are arranged on the end parts, wherein the height of the tail of the skirt is 8mm, the distance between the central line of each pin hole and the top plane of the high-compression ratio piston is 33mm, and the diameter is 18 mm; the length of each section of the multi-section groove at the pin hole is 20mm, the total length is 37mm, the height is 21mm, and the maximum depth of each section of the groove is 2 mm; 2 symmetrical cylindrical pin shaft sleeves are arranged on the inner sides of the pin holes at the two ends, the bottom ends of the pin shaft sleeves are set to be horizontal rectangular planes, the outer diameter of each pin shaft sleeve is 26mm, the inner diameter of each pin shaft sleeve is 18mm, and the length of each pin shaft sleeve is 17 mm; 2 symmetrical reinforcing straight ribs are arranged between the pin shaft sleeve of the piston inner cavity and the top of the piston inner cavity.
The reinforced straight rib in the technical scheme is as follows: the cross section of the reinforced straight rib between the pin shaft sleeve of the piston inner cavity and the top of the piston inner cavity is a rectangle with the width of 6mm and the length of 12mm, and the length of the reinforced straight rib in the diameter direction is 13 mm.
In the technical scheme, transition fillet curved surfaces are arranged at the top of the inner cavity and the side wall of the inner cavity, and the radius of the transition fillet curved surfaces is 5 mm; no. 1 transition fillets are arranged on the bottom surface of the end part and the side wall of the inner cavity, and the radius of the No. 1 transition fillet is 2 mm; no. 2 transition fillets are arranged on the side wall of the skirt tail and the bottom of the skirt tail, and the radius of the No. 2 transition fillets is 2 mm; the chamfer angle at the pin hole was 30 degrees and 1mm long.
Compared with the prior art, the beneficial effects of the utility model are that:
1. the high compression ratio piston for the small gasoline engine can reduce the volume of a combustion chamber due to the arrangement of the lug boss on the top plane of the piston, so that the compression ratio of the gasoline engine is improved, the effective thermal efficiency of the gasoline engine is further improved, and the effective fuel consumption rate of the gasoline engine is reduced;
2. the high compression ratio piston for the small gasoline engine can reduce flame propagation distance and shorten flame propagation time due to the arrangement of the lug boss on the top plane of the piston, reduces the effects of further compression and thermal radiation on unburned mixed gas at the final combustion position to a certain extent, generates spontaneous combustion before the flame front reaches, and reduces the detonation probability of the gasoline engine;
3. the high compression ratio piston for the small gasoline engine is characterized in that the boss is arranged on the top plane of the piston, the transition fillet curved surface is arranged at the top of the inner cavity and the side wall of the inner cavity, and the reinforcing straight rib is arranged between the pin hole sleeve of the inner cavity of the piston and the piston top, so that the strength of the piston can be enhanced, and the durability can be improved;
4. the high compression ratio piston for the small gasoline engine is convenient for guiding in a piston pin due to the chamfer arranged at the pin hole;
5. a small-size petrol engine high compression ratio piston reduce skirt tail height owing to reduce I gas ring groove and II gas ring groove width, the whole height of piston reduces to be equipped with the multistage recess at the pinhole tip, from the theory, can realize the lightweight under the prerequisite of guaranteeing the engine performance, reduce the piston height, reduce the friction, and then reduce petrol engine mechanical loss, improve petrol engine thermal efficiency.
Drawings
The invention will be further described with reference to the accompanying drawings:
FIG. 1 is a front view of a high compression ratio piston structure for a small gasoline engine according to the present invention;
FIG. 2 is a sectional view of a high compression ratio piston structure for a small gasoline engine according to the present invention in a front view;
FIG. 3 is a sectional view of the high compression ratio piston structure for a small gasoline engine according to the present invention, as viewed from the left;
fig. 4 is a top view of the structure of the high compression ratio piston for a small gasoline engine according to the present invention;
FIG. 5 is a graph showing the average pressure in the cylinder before and after the improvement of the high compression ratio piston for a small gasoline engine according to the present invention;
FIG. 6 is a graph of the instantaneous heat release rate before and after the improvement of a high compression ratio piston for a small gasoline engine according to the present invention;
fig. 7 is a sectional view of a top view of a high compression ratio piston structure for a small gasoline engine according to the present invention;
in the figure: 1. the novel oil cylinder comprises a head part, a skirt part, a pin hole, a cambered part, a tip part, an inner cavity, a gas ring groove, a skirt tail, a reinforcing straight rib, a transition fillet curved surface, a transition fillet, a number 14.2, a cylindrical boss and a multi-section groove, wherein the cambered part is 4, the tip part is 5, the inner cavity is 6, the gas ring groove is 7, the gas ring groove is I, the gas ring groove is 8, the oil ring groove is 9, the skirt tail is 10, the reinforcing straight rib is 11, the transition fillet curved surface is 12, the transition fillet is 13.1, the transition fillet is 14.2, the cylindrical boss is 15, and the multi-section groove is 16.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings:
referring to fig. 1, the technical scheme of the utility model is to improve the design by using a certain gasoline engine piston as a prototype, and to calculate and verify in simulation software.
The high compression ratio piston comprises a head part 1 and a skirt part 2, and referring to fig. 4, the head part 1 and the skirt part 2 are cylindrical structural parts, the bottom end of the head part 1 is equal to the top end of the skirt part 2 in diameter, and the bottom end of the head part 1 is connected with the top end of the skirt part 2 into a whole.
The head part 1 comprises a piston top part and a sealing groove:
the top of the piston is a cylindrical boss which is 1.7mm higher than the plane of the top of the piston and has a diameter of 55mm, the cylindrical boss is positioned at the center of the plane of the top end of the piston with high compression ratio, and the cylindrical boss is collinear with the rotation axis of the piston with high compression ratio;
the sealing groove comprises a gas ring groove I7, a gas ring groove II 8 and an oil ring groove 9, the width of the gas ring groove I and the width of the gas ring groove II are both set to be 1.2mm, and the width of the oil ring groove 9 is 1.5 mm; the depth of each sealing groove is 2 mm; the first gas ring groove 7, the second gas ring groove 8 and the oil ring groove 9 are sequentially arranged in parallel from top to bottom, the rotation center line of the sealing groove is collinear with the rotation center line of the piston with high compression ratio, the distance between the upper groove wall of the first gas ring groove 7 and the plane of the top of the piston is 1.2mm, the width of the groove wall between every two adjacent grooves is 1.2mm, and more precisely, the width between the lower groove wall of the first gas ring groove 7 and the upper groove wall of the second gas ring groove 8, and the width between the lower groove wall of the second gas ring groove 8 and the upper groove wall of the oil ring groove 9 are 1.2 mm.
The skirt is a cylindrical structural member, the diameter of the inner cavity 6 is 60mm, the depth is 40mm, and a part of an arched solid is cut off from the tail of the skirt along the diameter direction, so that 2 symmetrically arranged arc parts 4 and 2 symmetrically arranged end parts 5 are formed, and pin holes 3 are arranged on the end parts 5. Wherein the height of the skirt tail 10 is 8 mm; the distance between the central line of the pin hole 3 and the top plane of the high compression ratio piston is 33mm, and the diameter of the pin hole is 18 mm; each section of the multi-section groove 16 at the pin hole 3 is 20mm long, 37mm in total length, 21mm in height, and 2mm in maximum depth; the inner sides of the pin holes at two ends are provided with 2 pin shaft sleeves which are symmetrically arranged and are cylindrical structural members, the bottom ends of the pin shaft sleeves are arranged into a horizontal rectangular plane along the diameter direction of the high compression ratio piston, the outer diameter is 26mm, the inner diameter is 18mm, and the length is 17 mm; 2 reinforcing straight ribs 11 which are symmetrically arranged are arranged between the pin shaft sleeve of the piston inner cavity and the top of the piston inner cavity, the cross section of each reinforcing straight rib is a rectangle with the width of 6mm and the length of 12mm, and the length of each reinforcing straight rib is 13mm along the diameter direction.
The radius of the transition fillet curved surface 12 between the top of the inner cavity and the side wall of the inner cavity is 5 mm; the radius of a No. 1 transition fillet 13 between the bottom surface of the end part and the side wall of the inner cavity is 2 mm; the radius of the No. 2 transition fillet 14 between the side wall of the skirt tail and the bottom of the skirt tail is 2 mm; the chamfer angle at the pin hole 3 is 30 degrees and the length is 1 mm.
The overall height of the piston is 45 mm.
The rest structure is the same as the original gasoline engine piston.
The same simulation model is used for simulation calculation analysis on the pistons before and after improvement, and simulation result data are as follows. According to simulation result data, the indicated work, the average indicated pressure and the indicated thermal efficiency of the gasoline engine are obviously improved along with the increase of the compression ratio. As can be seen from fig. 5 and 6, the compression ratio is increased, so that the in-cylinder pressure and the instantaneous heat release rate are both significantly increased.
TABLE 1 work and mean pressure indications of original and optimized solutions
Item Original machine Improvements in or relating to
Compression ratio epsilonc 8.8 11.1394
Indicating work/N.m 217.202 390.146
Mean indicated pressure/Pa 276550 496749
Indicating thermal efficiency 23.51310% 36.57692%
The simulation result is further analyzed, and the pressure and the humidity of the cylinder generated during compression are improved due to the improvement of the compression ratio, so that the gasoline molecule atomization effect is better, and the combustible mixture is more fully and uniformly mixed. When the spark plug ignites the combustible mixture, the combustion speed is faster, and larger explosion energy is released. In addition, the increase of the cylinder pressure shows that the capacity of the working medium for pushing the piston to do work outwards is improved. From the perspective of heat transfer loss, the arrangement of the lug boss reduces the flame propagation distance, shortens the combustion time, reduces the detonation probability, and is beneficial to reducing the energy loss caused by heat transfer.
In conclusion, through the optimization and improvement of the piston structure, the cylindrical boss which is 1.7mm higher than the plane of the top of the piston and has the diameter of 55mm is arranged at the top of the piston, so that the compression ratio can be improved, and the heat efficiency of the whole gasoline engine is improved; the cylindrical boss can also reduce flame propagation distance, shorten flame propagation time, reduce heat transfer loss and reduce detonation probability; theoretically, the reduction of the width of the sealing ring groove and the height of the skirt tail to reduce the height of the piston and the arrangement of the multi-section grooves at the end parts of the pin holes 3 can realize light weight and reduce friction, and further the consumption rate of fuel oil can be further reduced. In addition, transition fillet curved surfaces 12 are arranged at the top of the inner cavity and the side wall of the inner cavity, and a reinforcing straight rib 11 is arranged between the pin hole sleeve of the inner cavity of the piston and the top of the piston, so that the strength of the piston can be improved, and the durability of the piston can be improved.

Claims (5)

1. A high compression ratio piston for a small gasoline engine is characterized by comprising a head part (1) and a skirt part (2); the head part (1) and the skirt part (2) are cylindrical structural parts, the diameter of the bottom end of the head part (1) is equal to that of the top end of the skirt part (2), and the bottom end of the head part (1) is connected with the top end of the skirt part (2) into a whole;
the head (1) comprises a piston top and a sealing groove;
the top of the piston is a cylindrical boss which is 1.7mm higher than the plane of the top of the piston and has a diameter of 55mm, the cylindrical boss is positioned at the center of the plane of the top end of the piston with high compression ratio, and the cylindrical boss is collinear with the rotation axis of the piston with high compression ratio;
the sealing groove comprises a gas ring groove I (7), a gas ring groove II (8) and an oil ring groove (9), the widths of the gas ring groove I (7) and the gas ring groove II (8) are both set to be 1.2mm, and the width of the oil ring groove (9) is 1.5 mm; the depth of each sealing groove is 2 mm; the first gas ring groove (7), the second gas ring groove (8) and the oil ring groove (9) are sequentially arranged in parallel from top to bottom, the distance between the upper groove wall of the first gas ring groove (7) and the plane of the top of the piston is 1.2mm, and the width of the groove wall between every two adjacent grooves is 1.2 mm.
2. The high compression ratio piston for a small gasoline engine as set forth in claim 1, wherein the widths of the groove walls between the adjacent two grooves are each 1.2 mm:
the widths between the lower groove wall of the gas ring groove I (7) and the upper groove wall of the gas ring groove II (8) and between the lower groove wall of the gas ring groove II (8) and the upper groove wall of the oil ring groove (9) are both 1.2 mm.
3. The high compression ratio piston for a small gasoline engine as set forth in claim 1, wherein said skirt portion (2) is a cylindrical structural member, the inner cavity (6) has a diameter of 60mm and a depth of 40mm, and a partial solid of an arcuate shape is cut off in a diametrical direction at a skirt end to form 2 symmetrically disposed arcs (4) and 2 symmetrically disposed end portions (5), and pin holes (3) are provided on the end portions (5), wherein a height of the skirt end (10) is 8mm, a distance between a center line of the pin hole (3) and a top plane of the high compression ratio piston is 33mm, and a diameter thereof is 18 mm; each section of the multi-section groove (16) at the pin hole (3) is 20mm long, the total length is 37mm, the height is 21mm, and the maximum depth of each section of the groove is 2 mm; the inner sides of the pin holes at two ends are provided with 2 symmetrical cylindrical pin shaft sleeves, the bottom ends of the pin shaft sleeves are arranged into a horizontal rectangular plane, the outer diameter of each pin shaft sleeve is 26mm, the inner diameter of each pin shaft sleeve is 18mm, and the length of each pin shaft sleeve is 17 mm; 2 symmetrical reinforcing straight ribs (11) are arranged between the pin shaft sleeve of the piston inner cavity and the top of the piston inner cavity.
4. A high compression ratio piston for a small gasoline engine as set forth in claim 3, wherein said reinforcing straight rib (11) is:
the cross section of the reinforced straight rib (11) between the pin shaft sleeve of the piston inner cavity and the top of the piston inner cavity is a rectangle with the width of 6mm and the length of 12mm, and the length of the reinforced straight rib (11) along the diameter direction is 13 mm.
5. The high compression ratio piston for the small gasoline engine as defined in claim 3, wherein a transition round-corner curved surface (12) is provided at the top of the inner cavity (6) and the side wall of the inner cavity (6), and the radius of the transition round-corner curved surface (12) is 5 mm; no. 1 transition fillets (13) are arranged on the bottom surface of the end part and the side wall of the inner cavity, and the radius of the No. 1 transition fillet (13) is 2 mm; no. 2 transition fillets (14) are arranged on the side wall of the skirt tail and the bottom of the skirt tail, and the radius of the No. 2 transition fillets (14) is 2 mm; the chamfer angle at the pin hole (3) is 30 degrees and the length is 1 mm.
CN202121056420.3U 2021-05-18 2021-05-18 High compression ratio piston for small gasoline engine Expired - Fee Related CN215256497U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202121056420.3U CN215256497U (en) 2021-05-18 2021-05-18 High compression ratio piston for small gasoline engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202121056420.3U CN215256497U (en) 2021-05-18 2021-05-18 High compression ratio piston for small gasoline engine

Publications (1)

Publication Number Publication Date
CN215256497U true CN215256497U (en) 2021-12-21

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ID=79456141

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202121056420.3U Expired - Fee Related CN215256497U (en) 2021-05-18 2021-05-18 High compression ratio piston for small gasoline engine

Country Status (1)

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Granted publication date: 20211221