WO2020078088A1

WO2020078088A1 - Elastic variable-length piston and design and manufacturing method therefor

Info

Publication number: WO2020078088A1
Application number: PCT/CN2019/100414
Authority: WO
Inventors: 刘金宏
Original assignee: 广州宏大动力科技有限公司
Priority date: 2018-10-19
Filing date: 2019-08-13
Publication date: 2020-04-23
Also published as: CN110360021A

Abstract

An elastic variable-length piston and a design and manufacturing method therefor. The piston refers to the elastic variable-length piston, of which the length is elastically variable and which is an elastic energy storage structure; the elastic energy storage structure has the function of storing energy and rapidly converting elastic potential energy. Rapid energy conversion for working medium internal energy of a reciprocating piston type internal combustion engine is achieved, so that the highest temperature and the highest pressure of combustion can be reduced and controlled, the compression ratio of the internal combustion engine can be improved, the thermal efficiency of the internal combustion engine is improved, the mechanical efficiency is effectively improved, and emission of harmful substances can be reduced.

Description

Elastic variable length piston and its design and manufacturing method

Technical field

The invention relates to a reciprocating piston internal combustion engine, especially a piston of a reciprocating piston internal combustion engine.

Background technique

The internal combustion engine is a heat engine in which the fuel is burned inside the machine to convert energy into power for external work; the reciprocating piston internal combustion engine refers to the reciprocating linear movement of the piston in the cylinder. The linear motion of the piston is converted into a rotary motion of the crankshaft. The reciprocating piston engine is the most commonly used engine. The internal combustion engine described below generally refers to the reciprocating piston engine. Reciprocating piston engines can be divided into two types: ignition type and compression ignition type according to the ignition method. They can be divided into gasoline engine, diesel engine, natural gas engine, LPG engine, ethanol engine and dual fuel engine, etc. Generally, gasoline engine and diesel engine are commonly used . Gas fuel and gasoline have poor anti-knock resistance and are prone to deflagration, so the ignition method is generally used; diesel has good anti-knock resistance, so diesel engines use compression ignition.

From the perspective of the history of internal combustion engines, in 1860, Lenoir in France invented the first practical gas engine with a thermal efficiency of less than 5%; in 1876, Nikolaus August Otto invented a four-stroke internal combustion engine with thermal efficiency It reached 14%. By 1884, the thermal efficiency had reached 20%. In 1892, Diesel in Germany invented a compression ignition diesel engine with a thermal efficiency of 26%. Since then, more than a hundred years have passed. Many new technologies, such as supercharging technology, variable valve technology, etc., have greatly improved the thermal efficiency of internal combustion engines. The current thermal efficiency of gasoline engines is generally around 35%, up to 40%, and the thermal efficiency of diesel engines is generally around 40%. Up to about 46%; but it is extremely difficult to further improve the thermal efficiency of the internal combustion engine. On the other hand, the emissions of internal combustion engines will cause environmental pollution. The harmful substances emitted are: sulfur oxides (mainly sulfur dioxide SO ₂ ), carbon monoxide (CO), nitrogen oxides (NO _x ), hydrocarbons (HC) , Particulate matter (PM), odor (mainly products of incomplete combustion, such as various aldehydes), carbon dioxide (CO ₂ ), etc., as well as noise pollution, early gasoline also contains lead for anti-explosive Chemicals, all now use unleaded gasoline, lead is very little; most countries have implemented environmental protection to develop their own emission standards, and the requirements of emission standards are becoming more and more strict, Europe began to implement the Euro Ⅰ standard in 1992 , The Euro II standard was implemented in 1996, the Euro III standard was implemented in 2000, the Euro IV standard was implemented in 2005, the Euro V standard was implemented in 2008, and the Euro VI standard was implemented in 2014. Compared with the previous standard, the Euro VI standard Things have been greatly reduced; China began to implement the National I (equivalent to European I) standard in April 2001, the National II standard from July 2004, and the National III standard in July 2007, from 2010 to The National IV standard will be gradually implemented in 2014, the National V standard will be implemented in 2018, and the National VI standard will be implemented by 2020.

The methods for improving the thermal efficiency of reciprocating piston internal combustion engines include increasing the compression ratio (and expansion ratio), supercharging technology, Miller cycle technology, direct injection technology in the fuel cylinder, exhaust gas recirculation technology, optimizing the combustion process, optimizing the intake and exhaust system , Reduce friction loss, reduce heat loss, etc., but the most important means is to increase the compression ratio. At present, the compression ratio of gasoline engines is generally between 9--12, and the highest Mazda engine compression ratio is even 14; the compression ratio of diesel engines is generally between 12--22, and the maximum can even reach 25, but the compression ratio must be increased Subject to various restrictions, on the one hand, the limitations of the body material, especially the gasoline engine, a larger compression ratio will cause gasoline to burn more violently, and produce high temperature and high pressure, which is prone to deflagration and cause engine knock, thereby damaging the engine body. On the other hand, under high-temperature and high-pressure environments, nitrogen oxides (NO _x ) are more likely to be produced. Therefore, in order to achieve higher cylinder pressures, some designs use exhaust gas aftertreatment catalytic reduction technology (SCR), and even use reduced Air-fuel ratio and exhaust gas recirculation technology (EGR), as the amount of combustion oxygen decreases, can indeed increase the cylinder pressure and reduce the production of nitrogen oxides, but due to the lack of oxygen combustion, it is easy to generate carbon monoxide, adding new harmful emissions Therefore, with the increasingly strict emission regulations, under the existing technical conditions, the appropriate reduction of the compression ratio is more conducive to reducing The formation of oxides and carbon monoxide can be effectively reduced by appropriately reducing the efficiency. Therefore, many diesel engines now have a compression ratio between 14--16, and the compression ratio is reduced compared with the previous one, so as to reduce the thermal efficiency of the internal combustion engine to achieve reduction The purpose of harmful emissions.

Since reciprocating piston engines are relatively mature, many new technologies have been applied. In the case of meeting increasingly strict emission standards, even if you want to increase the thermal efficiency of reciprocating piston internal combustion engines a little bit, it becomes extremely difficult.

Although great progress has been made in improving the thermal efficiency and reducing harmful emissions of reciprocating piston internal combustion engines, the thermal efficiency of gasoline engines can reach up to 40% and the thermal efficiency of diesel engines can reach up to about 46%, but overall it is still very unsatisfactory. The thermal efficiency of internal combustion engines is far from half That is to say, most of the fuel is not used and wasted, further improving the thermal efficiency of the reciprocating piston internal combustion engine and effectively reducing harmful emissions have become a difficult problem to be solved when going to the reciprocating piston internal combustion engine.

A

 references:

 1. "Internal Combustion Engine Science", Machinery Industry Press, editor in chief: Liu Shenghua, Zhou Longbao, deputy editors: Han Yongqiang, Wang Zhong.

 2. "Principle of Internal Combustion Engine", Huazhong University of Science and Technology Press, chief editor: Liu Yongchang.

 3. "Advanced Technology and Principles of Internal Combustion Engines", Tianjin University Press, edited by: Yao Chunde.

 4. "Design of Internal Combustion Engine", Mechanical Industry Press, edited by: Yuan Zhaocheng.

technical problem

How to improve the thermal efficiency of internal combustion engines and effectively reduce harmful emissions is a difficult problem in the current design and manufacture of internal combustion engines.

Technical solution

In order to solve the problems of low thermal efficiency and reduction of harmful emissions of reciprocating piston internal combustion engines, the present invention provides a new solution, which has new developments in the theoretical principles of internal combustion engines, greatly improving the reciprocating piston type from theory and design and manufacturing The thermal efficiency of the internal combustion engine can effectively reduce the emission of harmful substances at the same time, and can also greatly improve the power performance and power increase of the reciprocating piston internal combustion engine, effectively reduce the unit displacement of the fuselage mass, and improve the power-mass ratio (power-to-weight ratio ).

 In order to more clearly explain the new scheme of the reciprocating piston internal combustion engine of the present invention, taking the current four-stroke reciprocating piston engine as an example, the working process and energy conversion process of the reciprocating piston internal combustion engine are first analyzed. The working process of a four-stroke reciprocating piston engine is that the piston movement forms four sequential steps of intake, compression, combustion and expansion work, and exhaust to form a working process, and the working process repeats the cycle continuously. Only expansion in these processes Work is the process of doing work externally, and all other processes are needed to better achieve work. The process of engine expansion work is that the working gas pressure pushes the piston to move linearly to do work. The piston is converted into rotary motion of the crankshaft through the connecting rod, and the power is output from the crankshaft to do work. Many books and documents define the internal combustion engine as a machine that converts thermal energy (or internal energy) into mechanical energy. The inventor believes that this statement is incorrect. From the perspective of energy, first of all, the so-called mechanical energy refers to the sum of kinetic energy and potential energy. Potential energy is divided into gravitational potential energy and elastic potential energy. Therefore, kinetic energy, gravitational potential energy, and elastic potential energy can be collectively referred to as mechanical energy. The combustion of fuel in the internal combustion engine converts the chemical energy into the internal energy of the combustion medium. A part of the internal energy of the working medium is consumed by the heat dissipation of the cylinder temperature. Some of the internal working medium can promote the piston to do work, and part of the function energy is consumed as friction. Converted into mechanical kinetic energy (such as engine acceleration), part of the energy is used to overcome the load of the engine to do work, and part of the internal energy is consumed with the exhaust gas, becoming exhaust gas internal energy and exhaust gas aerodynamic energy. The load refers to the resistance burden that the engine bears externally. For different loads, the energy conversion method is different; for example, the internal combustion engine drives the generator to generate electricity, and the load is the generator, and its operating speed is fixed, so its kinetic energy remains unchanged. The mechanical energy is also the same, but the internal combustion engine drives the generator to rotate through the power transmission. The internal combustion engine uses the mechanical transmission power to make the generator overcome the electromagnetic resistance to do work. The internal combustion engine working medium can be indirectly converted into electrical energy through the power transmission; for the energy conversion of the car, The car engine transfers power to the wheels mechanically to overcome the frictional resistance of the wheels to do work. Part of the energy for the work is converted into frictional heat energy, part of the work is to overcome the air resistance, and part of the work energy is converted into the kinetic energy of the car when accelerating. The internal working energy of the engine working fluid is converted into multiple energy through mechanical power transmission; therefore, the load is not necessarily mechanical energy, but can be converted into various forms of energy. For convenience and clarity, the load consumption is defined here. The function quantity is load work, or called Load energy. The friction resistance, kinetic energy resistance and load resistance of the internal combustion engine are all the consumption resistance of the internal combustion engine except temperature heat dissipation and exhaust internal energy. They all belong to the mechanical resistance of the internal combustion engine. Here, they are defined as the load of the internal combustion engine, and the work of the load consumption is defined as the load work. Or load energy, which is the energy consumed by resistance. In this way, the energy process of the internal combustion engine can be simplified simply and simply as:

 Working fluid internal energy = heat dissipation + exhaust internal energy + load energy (or load work)

Load energy (or load work) = frictional energy consumption + engine kinetic energy increment + tail aerodynamic energy + load energy (load work)

 It can be seen from the above that the process of reciprocating piston internal combustion engine working fluid expansion is the process of converting the internal energy of the working fluid into load energy (load work), and the process of internal combustion engine external work is the conversion of the internal energy of the working fluid into load energy (load work) the process of.

 The solution of the present invention adopts a new method that is different from the energy conversion of the existing (referring to the current or traditional, prior to the solution of the present invention) reciprocating piston internal combustion engine, and introduces a new energy conversion process. The energy conversion of the solution of the present invention is based on theoretical principles It is different from the existing internal combustion engine. In order to distinguish the difference between the energy conversion method of the present invention and the existing internal combustion engine, and to make it simple and clear, this description compares the unique and related resistance, energy and process of the present invention with the existing The resistance load of the internal combustion engine is distinguished, and only the resistance mode of the existing internal combustion engine is defined as the load, and the energy consumed by the resistance of the existing internal combustion engine is defined as the load energy (or load work), and the resistance and energy added by the new scheme are not attributed to the load and Load energy. This new solution is to construct an elastic variable-length piston. The piston uses a semi-rigid semi-elastic variable-length piston. The length of the piston is elastically variable. It is an elastic energy storage structure; the elastic energy storage structure is an elastic structure with its functions The role is to store energy and quickly convert elastic potential energy to ensure the smooth operation of the engine, it can not consume energy itself. When the pressure of the combustion chamber is equal to or lower than the preset value, the pressure of the combustion chamber against the piston is equal to or less than the elastic force of the elastically variable piston. The piston shows rigidity, and the combustion chamber also shows rigidity; when the pressure of the combustion chamber is stronger than the preset value At the set value, the pressure of the working fluid expansion work on the piston is greater than the elastic force of the elastic variable length piston. The piston behaves elastically, the combustion chamber also behaves elastically, the length of the piston is elastically compressed, and the energy in the combustion chamber working fluid can be converted into the elasticity of the piston Potential energy; when the pressure of the combustion chamber decreases, the external stress of the elastically variable piston is less than its elastic force, the length of the piston is elastically restored, and the elastic potential energy stored by the piston is converted into load energy; that is, during the expansion of the combustion medium of the internal combustion engine to do work, its combustion In addition to the internal energy of the working medium, the internal energy can also be converted into elastic potential energy, and then the stored elastic potential energy is converted into load energy, which is the process of adding the internal energy of the working medium into elastic potential energy and then into load energy. . In fact, all objects are deformed or elastically deformed by pressure. The so-called rigidity means that the shape and shape of a solid or solid component does not change, and it has nothing to do with extremely weak elastic deformation; elastic deformation is usually defined as the object after the external force is applied. The change of the relative position between points, when the external force is withdrawn, the solid returns to its original state; semi-rigid and semi-elastic means that it behaves rigidly under certain conditions and elasticity under another specific conditions. The energy conversion process of the internal combustion engine in the solution of the present invention can be expressed as follows:

 Conversion of internal energy and elastic potential energy:

 Internal energy of working medium —— → Heat dissipation + elastic potential energy + load energy (or load work)

 Conversion of elastic potential energy and load energy:

 Working fluid internal energy + elastic potential energy —— → heat dissipation heat + exhaust internal energy + load energy (or load work)

Generally speaking, the combustion process of the internal combustion engine is very rapid. In contrast, the internal reciprocating piston internal combustion engine converts the internal energy into load energy for a long time. The solution of the present invention increases the internal energy conversion of the working medium by constructing an elastic variable length piston It is the process of converting elastic potential energy into load energy. The conversion process of elastic potential energy can be very rapid, so that the internal energy of the working medium can be quickly converted into elastic potential energy and stored, and then slowly converted into load energy (or load work) , Which greatly accelerates the energy conversion process of the internal energy of the working medium. The energy of the internal energy of the working fluid can be rapidly converted, which can quickly reduce the energy of the internal energy of the working fluid, which can quickly reduce the temperature and pressure of the gas of the working fluid, which can reduce the loss of heat energy consumption caused by the temperature heat transfer. , And can reduce the damage of the high temperature and high pressure to the body and reduce the use of body material standards, to save the cost of internal combustion engine manufacturing and reduce the unit displacement of the body mass, improve the power-mass ratio (power-to-weight ratio), and can also achieve the reduction of exhaust gas harmful substances The purpose, especially important, is that due to the rapid conversion of the internal energy of the working fluid, the maximum temperature and pressure of the combustion can be reduced and controlled, so that the compression ratio of the reciprocating piston internal combustion engine can be greatly improved, and the Greatly improve the thermal efficiency of reciprocating piston internal combustion engines. Improving the power-to-mass ratio (power-to-weight ratio) not only has great benefits for the general application of reciprocating piston internal combustion engines, but also has a very important impact on the application of reciprocating piston internal combustion engines in the aviation field. Reducing the emission of harmful substances in the exhaust gas is also of great significance for protecting the environment and meeting increasingly strict engine emission standards. According to existing research, the formation of nitric oxide (NO) is an exponential function that changes with temperature. When the temperature is lower than 1800K, the production rate of nitric oxide (NO) is extremely low, while the production of nitrogen dioxide (NO ₂₎ ) Is also produced by nitric oxide (NO), the ratio of nitrogen dioxide (NO ₂ ) content to nitric oxide (NO) content is generally not more than 2%, so as long as the working gas temperature is kept below 1800K, it can greatly Reduce the production of nitrogen oxides (NO _x ), especially nitric oxide (NO), to achieve a significant reduction in the content of exhaust gas nitrogen oxides (NO _x ). Without considering the formation of nitrogen oxides (NO _x ), a relatively large air-fuel ratio can be used to achieve lean fuel combustion, excess air is easier to achieve full combustion, and carbon monoxide (CO) and carbon dioxide can be reduced. The purpose of particulate matter (PM) emission.

 Through the design and construction of multi-stage different elastic pressures and corresponding compressible lengths, the multi-stage piston length can be elastically variable to form a multi-stage elastic variable-length piston to achieve the characteristics of semi-elastic and semi-rigid under different multi-stage pressures and corresponding Different multi-stage lengths are elastically variable, can realize more functions, and can increase the compression ratio. For example, a larger elasticity elasticity will only decrease in length when the gas pressure in the combustion chamber is high. On this basis, another level of smaller elasticity elasticity can be set. At higher loads and pressures, The elastic length of this stage is completely compressed, and the compression performance is exactly the same as that of single-stage elasticity. However, when the load and pressure are relatively low, the cylinder sucks less gas. When the gas is compressed, this stage of elasticity is only partially compressed, and the length of the piston is also Only a part is reduced, so that when there is little gas, the compression can still maintain a higher pressure and a higher temperature, and the compression ratio relatively becomes higher dynamically, and few gases also have a higher temperature and Pressure, which makes it easier to burn, especially for compression ignition engines, easier to ignite when starting, and more fuel efficient when running at zero load idling speed; this is a smaller level when exhausting The length of the elastic force is fully extended to the maximum length, making the exhaust more clean and complete; during intake, the smaller length of the elastic force is also fully extended to the maximum length, making the cylinder volume length and capacity Becomes smaller, which realizes the Miller cycle, so that the compression ratio is less than the expansion ratio, the intake energy consumption can be effectively reduced during intake, and the gas can do more work during expansion work, which can be better improved. Mechanical efficiency. Therefore, the realization of a multi-stage elastic variable-length piston can increase the compression ratio, increase the initial compression temperature and pressure of a small amount of gas, realize a small amount of gas easier to burn, start more easily, exhaust more thoroughly, realize the Miller cycle, and achieve more mechanical efficiency high.

 One design and manufacturing method of the elastic variable-length piston is to construct an inner core-type elastic variable-length piston, as shown in FIG. 1, and FIG. 1 is a longitudinal cross-sectional structure diagram of the inner core-type elastic variable-length piston. 2. Inner core, 3. Constraint ring, 4. Piston pin, 5. Elastic layer (spring group). The inner core type elastic variable length piston is divided into a casing, an inner core and an elastic layer, etc .; the piston crown of the outer casing forms a combustion chamber together with the cylinder and the cylinder head. The casing contacts the cylinder and moves linearly along the cylinder; the inner core includes the piston pin seat and Connecting rod connection, the connection between the inner core and the connecting rod is similar to that of a conventional piston. The inner core does not contact the cylinder wall. The inner core can slide in the outer casing, so that the distance between the piston pin seat and the top of the piston can be changed to change the length of the piston; elasticity The layer is between the inner bottom of the outer casing and the top of the inner core, and is a partition layer constrained to be a semi-compressed spring group or elastic material, elastically constrained between the two ends of the elastic layer, so that the piston has semi-rigid semi-elasticity in the length direction Characteristics, which constitutes an inner core type elastic variable length piston. When the pressure on the piston top is equal to or less than the elastic force, the piston appears rigid; when the pressure on the piston top is greater than the elastic force, the elastic layer in the piston is compressed, the relative position of the piston top and the inner core moves and the distance decreases, the piston As the length decreases, part of the internal energy of the working fluid in the combustion chamber is converted into the elastic potential energy of the piston elastic layer; when the force on the piston top and the piston connecting rod is reduced, the length of the piston is elastically reset, the elastic force of the piston pushes the piston connecting rod, and the elastic potential energy of the piston Convert into load energy. Since the inner core can always be fully immersed in the lubricating oil, the friction between the inner core and the outer sleeve is immersion lubrication, which can effectively reduce the friction force. When the fuel in the combustion chamber is burning, when the gas pressure of the working medium is greater than the elastic force of the piston, the length of the piston is rapidly elastically compressed. At this time, the side pressure is almost zero, and the piston jacket and the inner core are immersed in lubricating friction, so the friction force is extremely small at this time. , That is, the piston moves a certain distance in the cylinder when the friction is extremely small, which can effectively reduce friction.

 In the inner core type elastic variable length piston, the elastic layer is constructed as a series of multiple elastic layers with different constrained elastic forces and corresponding different compression lengths, to construct the inner core type multi-stage elastic variable length piston, which has the foregoing The advantages and characteristics of the multi-stage elastic variable length piston.

 Another design and manufacturing method of the elastic variable length piston is to construct a separate elastic variable length piston, as shown in Figure 2, Figure 2 is a longitudinal section structure diagram of the split elastic variable length piston, marked in the figure: 3. Constraint ring, 4. Piston pin, 5. Elastic layer (spring group), 6. Top cover, 7. Pin seat, 8. Piston skirt, 9. Guide column. The split elastic variable length piston is divided into a top cover, a pin seat portion and an elastic layer; the top cover is the top of the piston sealing combustion chamber; the pin seat portion includes a pin seat, a piston skirt and a guide column, the pin seat and the piston connecting rod Connection, the piston skirt refers to the structure where the piston contacts the cylinder and bears the side stress. The guide column guides and constrains the linear movement of the piston top cover and the elastic layer (for example, the relative angular position of some piston tops and the cylinder head cannot be changed, which requires The guide column fixes the direction); the elastic layer is between the top cover and the pin seat, and is composed of a spring group or elastic material that is constrained to be semi-compressed, and the elasticity is constrained between the ends of the elastic layer, so that the piston is in the length direction Has the characteristics of semi-rigid and semi-elastic. The so-called separation means that the piston pin seat (especially including the piston skirt in contact with the cylinder) is separated from the piston top cover, which makes it difficult for the heat of the piston top cover to be transferred to the piston skirt, so that the general piston will not occur due to heat The friction force caused by excessive side stress caused by the expansion of the piston skirt is greatly increased, and even the phenomenon of pulling or patting the cylinder, and due to the separation of the piston skirt, the piston skirt and the cylinder wall can be completely immersed in lubrication Sliding friction, these two can greatly reduce the frictional resistance of the piston. When the pressure on the piston cap is equal to or less than the elastic force, the piston appears rigid; when the pressure on the piston cap is greater than the elastic force, the elastic layer in the piston is compressed, and the relative position of the piston cap and the pin seat portion moves and distance Shrinkage, the length of the piston is reduced, and part of the internal energy of the combustion chamber is converted into the elastic potential energy of the elastic layer of the piston; when the force of the piston top cover and the piston connecting rod is reduced, the length of the piston is elastically reset, and the elastic force of the piston pushes the piston connecting rod The elastic potential energy of the piston is converted into load energy.

 The split elastic variable length piston can also be constructed as a multi-stage elastic variable length piston, and the elastic layer is constructed as a series of multiple elastic layers with different constrained elastic forces and correspondingly different compression lengths, to construct a split multi-stage elastic variable length piston, It also has the advantages and benefits of the multi-stage elastic variable length piston described above.

 Elastically variable-length pistons have a very important role and significance for reciprocating piston internal combustion engines. The elastic variable length piston makes the reciprocating piston internal combustion engine have the advantages and functions discussed above, the most important of which is that it can greatly increase the compression ratio of the reciprocating piston internal combustion engine. Due to the elastically variable piston, the combustion chamber can be elastically expanded to reduce and control the maximum temperature and pressure of the gas, so that the gas compression pressure of the combustion chamber before ignition can be greatly improved. In theory, the gas pressure before ignition The pressure can reach the initial pressure of the combustion chamber when the length of the elastically deformed piston is shortened, and it can be even greater, so that the compression ratio can be greatly improved, or even increased several times! For example, for a general aluminum alloy gasoline engine, the maximum pressure in the cylinder is 4-6MPa, the supercharged gasoline engine can reach 6-11MPa, the diesel engine generally uses a cast iron body, the maximum pressure of the ordinary diesel engine can reach 6-9MPa, and the supercharged diesel engine can even reach 15-20MPa; but the compression ratio of existing gasoline engines is generally between 9-12, the pressure before ignition is generally around 1-2MPa, while the compression ratio of existing diesel engines is generally between 12-22, the pressure before ignition It can reach about 2-4MPa; the solution of the present invention is that the gas pressure can reach the highest pressure after compression. The maximum bearable pressure of the aluminum alloy body is 9--11MPa. The theoretical compression ratio of the solution of the present invention can reach more than 25-29 If the maximum pressure of the cast iron body of the diesel engine is 15-20 MPa, the maximum compression ratio of the solution of the present invention can reach 36-44 or more. Assuming that the compression process is an ideal adiabatic process, the specific theoretical calculation is as follows:

 Ideal gas state equation: PV / T = nR (constant)

According to the ideal gas state equation and the adiabatic process equation, the relationship between each state parameter can be obtained by simultaneous solution:

 T1 / T0 = (V0 / V1) ^ (k-1) and T1 / T0 = (P1 / P0) ^ (1-1 / k)

 Where k is the adiabatic index of adiabatic compression and adiabatic expansion, that is, the specific heat ratio. Generally speaking, the adiabatic index k of monoatomic gas is 1.66, the adiabatic index k of diatomic gas is 1.41, and the adiabatic index k of polyatomic gas is 1.33, the ideal adiabatic index of dry air is about 1.4.

 The compression ratio is ε, the gas pressure before compression is standard atmospheric pressure P0 = 0.1MPa, the volume is V0, the temperature is T0, and the gas pressure after compression is P1, the volume is V1, and the temperature is T1. With a value of k = 1.4, you get:

 P1 * V1 / T1 = P0 * V0 / T0, ε = V0 / V1

 P1 / P0 = V0 / V1 * (T1 / T0)

 P1 / P0 = ε * ε ^ (k-1)

 Ε ^ k = P1 / P0

 Ε = (P1 / P0) ^ (1 / k)

 When the highest pressure is 9MPa, P1 = 9, P0 = 0.1, we can get:

ε = (P1 / P0) ^ (1 / k) = (9 / 0.1) ^ (1 / 1.4) ≈ 25

 When the highest pressure is 11MPa, P1 = 11, P0 = 0.1, you can get:

ε = (P1 / P0) ^ (1 / k) = (11 / 0.1) ^ (1 / 1.4) ≈ 29

 When the highest pressure is 15MPa, P1 = 15, P0 = 0.1, we can get:

ε = (P1 / P0) ^ (1 / k) = (15 / 0.1) ^ (1 / 1.4) ≈ 36

 When the highest pressure is 20MPa, P1 = 20, P0 = 0.1, we can get:

ε = (P1 / P0) ^ (1 / k) = (20 / 0.1) ^ (1 / 1.4) ≈ 44

A

 The above are estimated values, which cannot be very accurate, but it can also be fully explained that compared with the existing reciprocating piston internal combustion engine, the solution of the present invention can greatly and exponentially increase the compression ratio, which can greatly Improve thermal efficiency.

 The engine compression ratio is greatly improved, which can greatly increase the temperature and pressure at the end of compression (that is, before ignition), and can also make ignition and combustion more rapid, especially for the stagnation period at the beginning of combustion, usually stagnation The period is the most time-consuming process of the combustion process. At higher temperatures and pressures, the lag period will be shortened quickly, thereby greatly improving the combustion efficiency; due to the large increase in the initial temperature and pressure of the combustion, it also makes the combustion more complete and difficult Residues are generated; also, the increase in combustion speed, especially the increase in combustion speed during the lag period, can greatly reduce the ignition advance angle, which can also reduce the negative work of the engine to improve mechanical efficiency, and the increase in combustion speed It can bring about an increase in engine speed, which can greatly increase the engine's power. When the fuel is burning, the combustion of the existing reciprocating piston internal combustion engine is almost equivalent to isometric heating, and the solution of the present invention is equivalent to approximately isobaric heating under high pressure because it quickly converts the internal energy of the working gas into elastic potential energy. Judging from the PV diagram of the internal combustion engine, in the process of combustion and work, the PV curve of the existing reciprocating piston internal combustion engine is a sharp spike after the fire, and then a steeply descending oblique arc line. After the fire, the curve is a small horizontal upward straight line (the elastic expansion process of the combustion chamber), and then the downward diagonal line, and the diagonal line will be relatively less steep (gas expansion and elastic recovery of the piston at the same time) Function), the scheme of the present invention effectively improves the curve properties of the PV graph. Under the same maximum pressure, the average pressure of the piston is greatly improved, especially when the arm of the crank torque is large, the piston pressure can be kept more. Much larger, the average torque of the crankshaft has been greatly improved, which can greatly improve the power, power and thermal efficiency of the engine.

For reciprocating piston internal combustion engines, especially for gasoline engines, elastically variable-length pistons can also reduce or even eliminate the occurrence of deflagration and knocking during combustion. Deflagration is the violent combustion of the rapid and rapid spontaneous combustion of the mixed gas, resulting in a sharp and steep rise in local temperature and pressure, resulting in a combustion phenomenon of shock waves and detonation. When deflagration occurs, the maximum pressure can reach more than 65MPa, which will seriously damage the engine body. The conditions under which deflagration occurs are generally abrupt combustion of a high-concentration gas mixture, or abrupt combustion at a higher temperature and pressure than normal. Existing researches on the operation of gasoline engines and diesel engines have shown that crude explosion combustion and even deflagration are prone to occur under high load conditions. This situation is precisely the combustion of high-concentration mixed gas and high temperature and high pressure. Therefore, the most effective way to reduce or eliminate deflagration is A good way is to reduce the concentration of the mixed gas as much as possible on the one hand, the lean burn (lean mixed gas combustion) should be used as much as possible, on the other hand, the temperature and pressure of the gas during the combustion should be reduced. At present, in order to prevent the occurrence of knocking, the existing gasoline engine's fuel injection system, whether it is port injection or in-cylinder direct injection, basically uses a pre-mixed air method to fully fuel and air during intake. Mixing, and then at the end of the compression, the ignition mixture is ignited at the ignition advance angle. This method is destined to have a high pre-ignition pressure, and it is also impossible to use a high compression ratio. It also determines that it is impossible to have a high thermal efficiency. The solution of the present invention uses an elastically variable-length piston, so that the combustion chamber can be elastically expanded, and the compression ratio can be greatly improved, but for gasoline or gas fuel, the premixed gas can no longer be compressed and then ignited and ignited, otherwise in the process of gas compression It may reach the spontaneous combustion ignition point and cause combustion, resulting in knocking, and it is impossible to achieve the purpose of normal engine work. Therefore, it is necessary to adopt a direct fuel injection compression ignition method like the diesel engine at the end of the end of compression. In order to prevent the occurrence of knocking, the solution of the present invention An elastic combustion chamber composed of elastically variable-length pistons can prevent extremely high temperatures and pressures, but it is necessary to take corresponding measures to prevent the concentration of the mixed gas from being too high when the mixed gas is burned. For the solution of the present invention, one measure to prevent the concentration of the mixed gas from being too high is that during combustion, the fuel injection nozzle is pulsed and injected in multiple times to burn, and the amount of fuel injected each time is small, similar to the fuel injection of diesel engines. Very high pressure and speed, so the concentration of the mixed gas generated by the mixture is not high, and the initial combustion temperature and pressure of the solution of the present invention at the end of the gas compression are relatively high, and the combustion speed is very rapid, so the interval between each injection can be extremely high Short, can fully meet the actual needs, will not cause a reduction in power performance, the specific time interval should be obtained from experimental data according to different actual conditions; in the combustion process of the solution of the present invention, the internal energy of the combustion working fluid is quickly converted into elastic potential energy The volume of the combustion chamber can be increased rapidly and elastically, and the concentration of the fuel gas mixture in the later period is greatly reduced, so the fuel injection amount in the later period can be increased accordingly. Lean combustion is an effective measure to eliminate deflagration, but it is difficult to practically apply to the existing internal combustion engine, because the existing internal combustion engine is a pre-mixed mode, lean combustion will seriously affect the power performance of the engine, and the initial combustion of the existing internal combustion engine, especially retarded combustion The combustion speed in the period is relatively slow, and it is difficult to achieve lean combustion through pulsed staged combustion. In addition, the existing internal combustion engine simply cannot solve the problems of excessively high temperature and excessively high pressure. The gasoline and gas of the solution of the present invention can also use the same compression ignition method as the diesel engine, that is to say, the solution of the present invention can realize an integrated gas fuel, gasoline, and diesel engine, and even use a mixed oil fuel of gasoline and diesel, even Can use gasoline, diesel, methanol, ethanol, dimethyl ether, biodiesel, and other fuels mixed with any synthetic fuel, a variety of synthetic fuel can greatly reduce the operating cost of the engine. In fact, the molar mass of gasoline is much smaller than that of diesel, and the density of gasoline is also smaller than that of diesel. However, when fully burned, the same quality or volume of gasoline consumes more air and emits more heat than diesel, that is, That is to say, compared with gasoline and diesel, under the same mass or volume, when fully burned, gasoline stores more energy and emits more heat, and the amount of gasoline is greater. According to the ideal gas state equation, gasoline is better than diesel. The gas expansion coefficient of the working fluid after combustion is greater, which is more conducive to the work of the gas working fluid, but the current gasoline engine generally has a lower thermal efficiency than the diesel engine, indicating that the gasoline engine has a much worse effect on the use of fuel than the diesel engine. The engine of the solution of the present invention is a fuel-integrated engine, and the thermal efficiency of the use of gasoline and diesel is almost the same. Due to the greater heat release of gasoline and the greater gas expansion coefficient, the engine of the solution of the present invention uses gasoline to have a greater thermal efficiency. Mixed gasoline can also get more benefits, which opens up a broad and brilliant prospect for the application of reciprocating piston fuel integrated engines and various synthetic fuels!

Beneficial effect

The solution of the present invention has the beneficial effects of storing more, and the beneficial effects have made significant progress, and even some of the beneficial effects are leaps and bounds.

1. Significantly increase the compression ratio, thereby greatly improving the thermal efficiency.

2. The maximum temperature is greatly reduced, effectively reducing the loss of heat transfer loss and effectively improving the thermal efficiency.

3. Greatly reduce and limit the maximum temperature and pressure to protect the body from damage.

4. Significantly reduce the discharge of harmful substances.

5. Significantly increase the average piston pressure and average torque of the engine, thereby greatly improving the engine's power performance, power and power.

6. Effectively reduce and avoid the occurrence of coarse explosion combustion and deflagration, promote the stable combustion of the engine, and effectively reduce the combustion noise.

7. Effectively reduce friction to improve mechanical efficiency.

8. A substantial increase in the initial combustion temperature and pressure can greatly increase the combustion speed, increase the engine speed, and increase the engine power.

9. Effectively reduce the mass of the airframe and improve the power-mass ratio (power-to-weight ratio) of the engine.

A reciprocating piston fuel integrated engine can be realized, and various fuel fuels can be used.

BRIEF DESCRIPTION

The drawings and their marks are explained below:

 Figure 1 is a longitudinal section structure diagram of an inner core type elastic variable length piston.

 Figure 2 is a longitudinal sectional structure diagram of a split elastic variable length piston.

 Explanation of marks in the figure:

1. Outer cover, 2. Inner core, 3. Restraint ring, 4. Piston pin, 5. Elastic layer (spring group),

6. Top cover, 7. Pin seat, 8. Piston skirt, 9. Guide column.

Best Mode of the Invention

High compression ratio fuel integrated engine

 The implementation example of the scheme of the present invention is a high compression ratio fuel integrated engine, that is, a reciprocating piston engine with a compression ratio of 30 or more, which can use various fuels respectively. The specific design and manufacturing method of this example is that on the basis of the existing supercharged diesel engine, the piston and fuel injection are designed and modified accordingly. The piston adopts a separate multi-stage elastic variable-length piston to make the combustion chamber elastic and become an elastic storage. The structure can make the reciprocating piston engine achieve the various functions of the solution of the present invention. The engine adopts a cast iron alloy body and can withstand pressures of more than 25MPa; the piston uses a two-stage elastic split multi-stage elastic variable-length piston; the initial pressure of the first-stage elastic combustion chamber of the piston is set to 20MPa, the maximum pressure is 25MPa, and the compression ratio 60 (the compression ratio when the compression pressure reaches the initial elastic pressure); set the initial pressure of the piston secondary elastic combustion chamber to 15MPa, the maximum pressure to 20MPa, and the compression ratio to 80 (when the compression pressure reaches the initial elastic pressure Compression ratio); the compression ratio (expansion ratio) can be adjusted between 8-80; the valves are electronically controlled to ensure the precise intake air required; the turbocharger is used for supercharging; the engine has a displacement of 1.6 liters The four-cylinder engine has a displacement of 0.4 liters per cylinder. In the solution of the present invention, since the mass of the piston is increased accordingly, if the piston stroke is larger and the speed of the piston is larger, then the inertial force of the piston will increase greatly, so In order to increase the speed of the engine, the piston stroke should be reduced as much as possible. A smaller stroke cylinder diameter ratio should be used. The small piston stroke requires high precision, but on the other hand, the mechanical efficiency should be improved. The piston stroke should be a bit longer, determined according to the specific needs, for simplicity the present embodiment uses the cylinder volume ratio of diameter to length of 1, calculated to obtain:

Cylinder or piston diameter D, cylinder volume length L:

V = πD ² L / 4, V = 0.4 * 10e (-3) * 10e9, D = L

D ³ = 1.6 * 10e6 / π = 509295.82

 D = L ≈ 79.86 mm

Piston stroke S (calculated according to compression ratio 30, the piston stroke is also the length of the crankshaft rotation diameter, which is twice the radius of the crank):

 S = L / 30 * 29 ≈ 77.20 mm

Piston connecting rod length l (generally 3 times the radius of the crank):

 l = S / 2 * 3 = 77.20 / 2 * 3 = 115.8 ≈ 116 mm

The first-stage elastic compressible length of the piston (the minimum compression ratio is 8, the gas combustion expansion at a fixed pressure is about 2 times, in this case set to 3 times):

 L1 = L / 8 * 3 – L / 60 = 79.86 / 8 * 3-79.86 / 60 ≈ 29 mm

The second-stage elastic compressible length of the piston (in this example, the distance between the compression ratio 80 and the compression ratio 60):

 L2 = L / 60-L / 80 = 79.86 / 60-79.86 / 80 ≈ 0.33 mm

Piston first-level elastic initial spring force:

^{F1 = P1 * πD 2/4} = 20 * π * 79.86 ^ 2/4 ≈ 100179.41 N ≈ 10222.39 kg

Maximum elasticity of first-level elasticity of piston:

^{F2 = P2 * πD 2/4} = 25 * π * 79.86 ^ 2/4 ≈ 125224.27 N ≈ 12777.99 kg

Piston secondary elastic initial spring force:

^{F3 = P3 * πD 2/4} = 15 * π * 79.86 ^ 2/4 ≈ 75134.56 N ≈ 7666.79 kg

Maximum elasticity of the secondary elasticity of the piston:

^{F4 = P4 * πD 2/4} = 20 * π * 79.86 ^ 2/4 ≈ 100179.41 N ≈ 10222.39 kg

A

 The spring force and elastic coefficient of the piston are determined according to the above calculation results respectively. The pressure and the constraining tension on the spring must also be able to withstand the above calculation standards, so as to design and manufacture a multi-stage elastic variable-length piston. A very important and key design of the fuel integrated engine of the solution of the present invention is the fuel injection mode. The fuel injection system can use a high-pressure electronically controlled common rail injection system similar to the existing diesel engine, and the fuel injection pressure should be consistent with the existing diesel engine. , The injection pressure can reach 80-160MPa, multiple nozzles can be used to spread the injection, and the injection is divided into multiple intervals and the combustion is divided into sections to control the combustion process, reduce coarse explosion combustion, and avoid the occurrence of deflagration. Since the maximum temperature and pressure of the combustion chamber are maintained for a longer time, the sealing of the piston must also be strengthened. For different fuels, because of the different combustion speeds of fuels, they may even be very different. For example, the combustion speeds of gasoline and diesel are quite different. You must set different injection times and intervals for different fuels. The method, specific and precise injection and time interval need to be determined after testing; for different fuels, different maximum speed limits must also be set.

 The running process of the engine in this example. The engine of this example also has four working cycle processes of intake, compression, combustion and expansion work and exhaust for a common reciprocating piston engine. When the engine is started, the intake of a small amount of air is controlled by the electronic control valve during intake, but the pressure and temperature of compression ignition must be reached (different fuel requirements are different). Due to the small intake air, compression is required It consumes relatively little energy; at the end of compression of the engine, and then injects high-pressure fuel at the ignition advance angle (the optimal ignition advance angle needs to be actually measured), the injection method must be multiple interval injections, and the amount of fuel injected per time is limited In order to prevent the occurrence of deflagration, the fuel burns very quickly due to the high temperature and pressure. At this time, the combustion chamber is equivalent to isobaric combustion during the combustion process. The elastic expansion of the combustion chamber does work, and part of the working fluid can be converted into piston II. When the pressure is greater than the initial elastic force of the first-level elasticity of the piston, the internal energy of the working fluid is also converted into the elastic potential energy of the first-level elasticity of the piston. With the rotation of the crankshaft, the conversion of the engine energy is the internal energy of the working fluid. It is the elastic potential energy and load energy. After the crankshaft rotates at a certain angle, the working medium can partially transfer. When the pressure is less than the elastic force, the working medium And elastic potential energy can be converted into a load can simultaneously; crank pin when the crankshaft is close to the lower dead point, the electric control valve opens, the exhaust gases; This completes the four working of the engine start. When the engine is running at idle speed, the intake air volume is also less and the fuel consumption is less; when the engine is running normally, the power required is larger and the intake air volume is larger. During the compression process, the secondary elasticity of the piston is completely Compression, the engine is actually operating in an elastic combustion chamber with a compression ratio of 60. Its operation and energy conversion are similar to those described above. When the load is large, you can use the Miller cycle to control the amount of intake air through the electronically controlled valve and supercharger, increase the actual compression ratio and increase the intake air boost to meet the requirements of the load, when the amount of incoming air is large At this time, the piston may be partially compressed before ignition, the actual expansion ratio will be reduced, the initial ignition pressure will also be increased, and the amount of fuel per cycle of the engine will also increase, but the engine power and power performance will be improved According to the design of this example, the expansion ratio of the engine can be dynamically adjusted between 8-80, and the amount of air intake and the amount of fuel per cycle can be dynamically adjusted between 1-10 times at least.

 Performance estimates for examples of the present invention. In the same situation, that is, when the same fuel and air are consumed, the compression ratio has been greatly improved, which is several times higher than the existing diesel and gasoline engines; the air pressure before ignition has also increased more than double or even several times, the piston The average pressure of work is increased by more than several times, and the power performance is also greatly improved. The power of the engine in this example is greatly improved compared to the existing similar diesel engine. The power of the comparable gasoline engine may even exceed several times. The maximum theoretical thermal efficiency is about 73%. With reference to the comparison between the existing actual engine thermal efficiency and the theoretical value, it can be estimated that the actual maximum thermal efficiency of the case of the present invention is about 61%.

 The example of the present invention is designed according to a standard compression ratio of 60 and a maximum compression ratio of 80. When the compression ratio is 80, less air intake can be used, and fuel consumption can also be saved at idle speed; similarly, when the load is small, the compression ratio can be automatically adjusted by the intake volume between 80-60 Adjustment. On the other hand, when more power and power are needed, the intake volume can be adjusted, or more air can be added through turbocharging, so that the compression ratio can be adjusted dynamically, and the compression ratio can be adjusted to 8-- Between 80, adding more air can add more fuel; compared with existing reciprocating piston engines of the same displacement, the overall power can be increased by several times! Of course, when the compression ratio becomes smaller and the power is increased, its thermal efficiency will also decrease. In addition, the initial combustion temperature and pressure of the engine of the solution of the present invention have been greatly improved, and the engine speed can also be greatly improved, which can also promote the further increase of the engine power, so even if it is conservatively estimated, Compared with the existing engine with the same displacement, the maximum power of the engine of the solution of the present invention can be increased by more than several times. In summary, the standard working compression ratio of the engine of the present invention's example solution is 60, but the compression ratio can be automatically adjusted between 8 and 80 by controlling the air intake, which has high power performance and high The thermal efficiency and relatively high power, and can effectively reduce harmful emissions.

Industrial applicability

The solution of the present invention can use all kinds of existing materials, and the material requirements do not exceed the existing standards. The design and process are relatively simple, the manufacturing cost is relatively low, and the energy of the internal energy of the reciprocating piston internal combustion engine is quickly converted. , Can reduce and control the maximum temperature and pressure of combustion, can greatly improve the compression ratio, thermal efficiency, power performance and power increase of the internal combustion engine, effectively improve the mechanical efficiency, and can greatly reduce the emission of harmful substances, can be used The reciprocating piston fuel integrated engine of various fuels is suitable for large-scale manufacturing and application, and has strong practicability.

Claims

A reciprocating piston internal combustion engine piston, characterized in that the piston is an elastic variable length piston, the piston uses a semi-rigid semi-elastic variable length piston, the length of the piston is elastically variable, and is an elastic energy storage structure; the elastic energy storage structure is An elastic structure, whose function is to store energy and quickly convert elastic potential energy; when the pressure of the combustion chamber is equal to or lower than the preset value, the pressure of the combustion chamber on the piston is equal to or less than the elastic force of the elastic variable-length piston, The piston behaves rigidly, and the combustion chamber also behaves rigidly; when the pressure of the combustion chamber is greater than the preset value, the pressure of the working fluid expansion work on the piston is greater than the elastic force of the elastically variable piston, the piston behaves elastically, and the combustion chamber also behaves as Elasticity, the length of the piston is elastically compressed, and the internal energy of the combustion chamber fluid is converted into the elastic potential energy of the piston; when the pressure of the combustion chamber is reduced, the external stress of the elastically variable piston is less than its elastic force, the length of the piston is elastically restored, and the stored potential energy Convert into load energy.
The reciprocating piston internal combustion engine piston according to claim 1, characterized in that: multi-stage different elastic pressures and corresponding compressible lengths are constructed to achieve multi-stage elastically variable piston length, forming a multi-stage elastic variable-length piston to achieve The characteristics of semi-elastic and semi-rigid under different multiple pressures and correspondingly different multi-stage length elasticity are variable.
The reciprocating piston internal combustion engine piston according to claim 1, characterized in that: an inner core type elastic variable length piston, which is divided into a casing, an inner core and an elastic layer, etc .; the piston top of the casing is composed of a cylinder and a cylinder head Combustion chamber, the outer casing is in contact with the cylinder and moves linearly along the cylinder; the inner core includes the piston pin seat and the connecting rod, the connection between the inner core and the connecting rod is similar to that of a conventional piston, the inner core does not contact the cylinder wall, the inner core can be inside the outer casing Slide, so that the distance between the piston pin seat and the top of the piston can be changed to change the length of the piston; the elastic layer is a semi-compressed spring group or a partition layer of elastic material between the bottom of the inner sleeve and the top of the inner core, elastic Constrained between the two ends of the elastic layer, the piston has semi-rigid and semi-elastic properties in the length direction.
The method for designing and manufacturing a piston of a reciprocating internal combustion engine according to claim 1, characterized in that: an inner core type elastic variable length piston is constructed, which is divided into a casing, an inner core and an elastic layer, etc .; the piston top of the casing and the cylinder, The cylinder head forms the combustion chamber together. The outer casing is in contact with the cylinder and moves linearly along the cylinder. The inner core includes the piston pin seat and the connecting rod. The connection between the inner core and the connecting rod is similar to that of a conventional piston. The inner core does not contact the cylinder wall. The inner core Can slide in the outer casing, so that the distance between the piston pin seat and the top of the piston can be changed to change the length of the piston; the elastic layer is constrained to be a semi-compressed spring group or elastic material between the bottom of the inner casing and the top of the inner core The separation layer is elastically constrained between the two ends of the elastic layer, so that the piston has semi-rigid and semi-elastic properties in the length direction; when the pressure on the piston top is equal to or less than the elastic force, the piston appears rigid; when the pressure on the piston top When it is greater than the elastic force, the elastic layer in the piston is compressed, the relative position of the piston top and the inner core moves and the distance decreases, the length of the piston decreases, the combustion chamber Part of the internal energy of the working medium is transformed into the elastic potential energy of the elastic layer of the piston; when the force on the piston top and the piston connecting rod is reduced, the length of the piston is elastically reset, the elastic force of the piston pushes the connecting rod of the piston, and the elastic potential energy of the piston is converted into load energy.
The method for designing and manufacturing a piston of a reciprocating piston internal combustion engine according to claim 4, characterized in that the elastic layer of the inner core elastic variable length piston is constructed as a plurality of elastic layers connected in series, with different constrained elastic forces and correspondingly different compression lengths , To construct an inner core type multi-stage elastic variable length piston.
The reciprocating piston internal combustion engine piston according to claim 1, characterized in that: a separate elastic variable length piston is constructed, which is divided into a top cover, a pin seat portion and an elastic layer; the top cover is the top of the piston sealing combustion chamber; The pin seat part includes a pin seat, a piston skirt and a guide post. The pin seat is connected with the piston connecting rod. The piston skirt refers to a structure where the piston contacts the cylinder and bears side stress. The guide post guides and restrains the piston cap and the elastic layer. Linear motion; the elastic layer is between the top cover and the pin seat, and is composed of a semi-compressed spring group or elastic material. The elasticity is constrained between the two ends of the elastic layer, making the piston semi-rigid and semi-elastic in the length direction Characteristics.
The design and manufacture method of a reciprocating piston internal combustion engine piston according to claim 1, characterized in that: a separate elastic variable length piston is constructed, which is divided into a top cover, a pin seat portion and an elastic layer; the top cover is a piston sealed combustion The top of the chamber; the pin seat part includes the pin seat, the piston skirt and the guide post, the pin seat is connected with the piston connecting rod, the piston skirt refers to the structure where the piston contacts the cylinder and bears the side stress, the guide post guides and restrains the piston top cover Linear movement with the elastic layer; the elastic layer is composed of a semi-compressed spring group or elastic material between the top cover and the pin seat portion, and the elastic layer is constrained between the two ends of the elastic layer, so that the piston has Semi-rigid and semi-elastic characteristics; the so-called separation means that the piston pin seat (especially including the piston skirt in contact with the cylinder) is separated from the piston top cover, which makes it difficult for the heat of the piston top cover to be transferred to the piston skirt; when the piston When the pressure on the top cover is equal to or less than the elastic force, the piston appears rigid; when the pressure on the top cover of the piston is greater than the elastic force, the elastic layer in the piston is compressed, and the phase between the top cover and the pin seat When the position moves and the distance is reduced, the length of the piston is reduced, and part of the internal energy of the combustion chamber is converted into the elastic potential energy of the elastic layer of the piston; when the force of the piston top cover and the piston connecting rod is reduced, the length of the piston is elastically reset, the piston The elastic force pushes the piston connecting rod, and the elastic potential energy of the piston is converted into load energy.
The method for designing and manufacturing a piston of a reciprocating piston internal combustion engine according to claim 7, characterized in that the elastic layer of the split elastic variable length piston is constructed as a plurality of elastic layers connected in series, with different constrained elastic forces and correspondingly different compression lengths, To construct a separate multi-stage elastic variable length piston.