Multifunctional piston assembly of internal combustion engine

Abstract

Three dimensions of compact internal combustion engine structure, high power density and combustion process stability are determined, and the multifunctional piston assembly of the internal combustion engine is provided. Comprising a piston top 1, a non-open piston ring 2, a piston ring 3, a piston skirt 4, an O-shaped spring 5, a cross 6, a scavenging piston 7, an upper positioning pin 8, a lower positioning pin 8 and a positioning seat 9. The O-shaped spring 5 determines the combustion stability of the piston assembly in a high-compression-ratio environment, the non-open piston ring 2 controls leakage of a working medium to guarantee formation of high pressure, and the cross 6 integrates the piston 1, the scavenging piston 7 and the O-shaped spring 5 and provides six-degree-of-freedom constraint to be connected with various reciprocating motion mechanisms. In addition to a general internal combustion engine (hereinafter referred to as a radial internal combustion engine) adapted to a radial piston arranged perpendicular to a power output shaft, an internal combustion engine solution (hereinafter referred to as an axial internal combustion engine) adapted to an axial piston arranged parallel to the power output shaft is included.

Description

TECHNICAL FIELD

[0001] A multi-functional piston assembly of internal combustion engine relates to the function components and combustion control technology of internal combustion engine piston. The combination of intensive function components and a flexible combustion chamber self-control technology determines a high compression ratio compression ignition combustion control environment of internal combustion engine, and improves the space size utilization rate of internal combustion engine. BACKGROUND

[0003] The low cost of the aviation piston engine occupies an important position in general aviation, unmanned aerial vehicles and their micro unmanned aerial vehicles, and the power-to-weight ratio and thermal efficiency are low, and there is a space for expansion in structure and work. Research shows that the improvement of the power-to-weight ratio of the general aviation piston engine is related to a series of complex problems of the piston engine, and the prominent problem is the poor stability of internal combustion engine combustion, low compression ratio and difficult improvement of thermal efficiency. Ultimately, it is due to the limitations of the rigid constant volume combustion chamber and its constant volume heating cycle theory environment and combustion control technology of traditional internal combustion engine. As we all know, the constant volume combustion process of internal combustion engine cannot be directly controlled, but relies on the input state to control the combustion state. Secondly, the maximum pressure generated by combustion is several times the initial combustion pressure, showing amplification. When there is a small difference from fuel combustion properties to fuel air ratio control precision, intake state, ignition or injection phase and injection law, ignition phase and the like, very irregular combustion is produced, and the combustion pressure fluctuates greatly. In order to prevent the internal combustion engine from producing deflagration, the compression ratio is limited in a lower range to ensure the normal operation of the internal combustion engine. For example, under the same working condition, the irregular variation of the maximum combustion pressure of gasoline engine with two adjacent cycles reaches ±28%, if the irregular variation is eliminated, the specific fuel consumption can be reduced by 10%~20%, and the irregular variation of the maximum combustion pressure of diesel engine reaches 50%, and the thermal efficiency changes by 7 percentage points. In addition, the structure layout of general internal combustion engine, the crankshaft connecting rod piston motion mechanism occupies 50% of the structure size of internal combustion engine, and there is a problem of low space utilization and low utilization rate of structural materials; from the conversion of mechanical motion, in addition to the reciprocating motion function of the piston, it is difficult to connect other motion mechanisms; from the integration of internal combustion engine component system, the function components occupy their independent space, and the space utilization is low. The present application comprehensively considers the above conditions, combines a high compression ratio compression ignition technology, intensifies the piston and its related function components, and proposes a multi-functional piston assembly of internal combustion engine.

[0004] The present application combines a high compression ratio compression ignition technology, realizes high power to weight ratio, and is a Chinese invention patent No. ZL2014 1 0128541.2, publication date: September 21, 2016, and named “a double piston internal combustion engine” including a piston (1), a cylinder (2), a cylinder cover (3), a pressure strain piston (4), an air bag (5), and a force piston (6), a high-pressure gas cylinder (7), a buffer spring (9), a normally closed electromagnetic valve (10), a pressure sensor (11), a pressure relief pipe (12), and a pressurizing pipe (13) are all arranged in the cylinder cover, a flexible combustion chamber is constructed by the elasticity of the air bag (5), a high compression ratio compression ignition environment is obtained, and the self-control combustion technology is based on the difference from the invention patent “a double piston internal combustion engine” (ZL 2014 1 0128541.2) which pursues the ideal constant pressure heating feature of the composite process, the auxiliary control parts are set to be more and complex, the layout of the overall structure and the size limitation are ignored, the “O” shaped spring 5 is used to replace the air bag (5) and other structure schemes in the invention patent “a double piston internal combustion engine” (ZL 2014 1 0128541.2) to follow the “O” shaped spring 5 spring stiffness heating feature composite process, realize the composite process of the flexible combustion chamber heating and the self-control combustion technology, combine the power to weight ratio requirements of the aviation piston engine and the portable micro internal combustion engine, and propose the present application. SUMMARY

[0005] The technical method of the present application is to combine the internal combustion engine structure optimization and the working performance, realize an internal combustion engine flexible combustion chamber and its combustion control technology by the “O” shaped spring 5, propose a working environment of a high compression ratio compression ignition technology, construct a piston assembly, integrate the functional components, realize the space size utilization rate of the functional components, and improve the power to weight ratio of the internal combustion engine.

[0006] To achieve the above-mentioned purpose, the technical solution of the present application is: a power piston including a piston top 1, a non-opening piston ring 2, a piston ring 3, and a piston skirt 4, a pre-tightening force is generated by pressing the O-shaped spring 5, and the elastic connection cross 6 is rigidly connected to the cross 6 of the piston assembly reciprocating guide shaft or the scavenging piston 7, clamps the O-shaped spring 5, the positioning seat 9 on the scavenging piston 7 positions the O-shaped spring 5, and the two positioning pins 8 fix the power piston and the scavenging piston, to constitute a multifunctional internal combustion engine piston assembly moving in the cylinder.

[0007] The cross 6 is a connecting part, the upper end and the lower end are provided with positioning holes outside the O-shaped spring 5, the middle part is provided with a motion conversion functional part connected with a variety of motion conversion mechanisms, and the rotation motion and the reciprocating linear motion are converted.

[0008] The piston top 1, the piston ring 3, the piston skirt 4, the O-shaped spring 5, the cross 6, and the scavenging piston 7 are coaxial.

[0009] The piston top 1, the piston ring 3, the piston skirt 4, the O-shaped spring 5, the cross 6, and the scavenging piston 7 are coaxial.

[0010] The piston top 1, the piston ring 3, the piston skirt 4, the O-shaped spring 5, the cross 6, and the scavenging piston 7 are coaxial.

[0011] The flexible combustion chamber heating composite process and its self-control combustion technology of the internal combustion engine, including the direct constraint of the combustion pressure regularity variation in the composite process, the fuel combustion in the flexible combustion chamber is regulated in the "O" spring 5 working range, the fuel combustion attribute is ignored, including the reliable ignition, the initial compression ratio of the mixed gas pressure combustion is determined under different mixing ratios of the working medium, the pressure of the compressed working medium follows the spring stiffness regularity and continuously increases, the compression ratio continuously increases, until the mixed gas pressure combustion, ensuring the self-control of the pressure combustion ignition, including the stable combustion process and the energy recycling, the working range of the composite process includes two stages, the first stage is the self-control combustion process-composite heating process, the compression process of the "O" spring 5 under the combustion pressure, the process of the volume of the flexible combustion chamber increasing with the pressure, the process of absorbing heat energy conversion and mechanical energy storage, in this process, the limitation of the combustion pressure follows the regularity of the elastic stiffness characteristics, maintains the stability of the combustion process, and blocks the accumulation of combustion chemical heat energy to produce deflagration, providing technical support for the mixed gas with high compression ratio pressure combustion; the second stage is the "O" spring 5 rebound process-composite mechanical rebound process, before the expansion process after the complete combustion in the flexible combustion chamber, the process of releasing mechanical energy, the process of the "O" spring 5 returning to the initial state, the pressure, volume and temperature reduction state of the working medium in the flexible combustion chamber follow the elastic stiffness change, the mechanical energy is fed back to the working medium in the flexible combustion chamber, the internal energy of the working medium is increased, and a way of internal combustion engine cycle work is obtained. In the composite process of the flexible combustion chamber, the mutual restriction between mechanical force and thermal force generated by the conversion between mechanical force and thermal force controls the stable combustion, forms a high compression ratio pressure combustion environment, and is also a technical way to improve the thermal efficiency.

[0012] The "O" spring 5 includes the pre-tightening force, working deformation, maximum stress deformation and structural size of the "O" spring 5, and the mechanical strength reliability of the material, including using the reciprocating motion space, the maximum stress deformation and the structural size can enter the cylinder.

[0013] The piston ring 2 is an "L" shaped section non-opening piston ring, including the non-opening piston ring avoiding the scraping interference of the edge of the two-stroke intake and exhaust port, adapting to the high compression ratio and the high pressure of the working medium, obtaining the minimum mixed gas leakage amount by means of the face seal and low contact stress generated by the combustion pressure and thermal expansion with the least number of piston rings, and reducing the opportunity rate of unstable combustion.

[0014] The cross 6 is a fixed platform and a motion conversion function component, which can be provided with three cylindrical sleeve pairs, including three cylindrical sleeve pairs forming three-dimensional space, including three moving pairs and three rotating pairs, and adapting to the connection of various moving mechanisms.

[0015] To achieve the above objectives, the flexible combustion chamber and its self-controlled combustion technology, which utilize a multi-functional internal combustion engine piston assembly with an "O"-shaped spring 5, have the following effects: 1. The multi-functional structure is compact and integrated, facilitating the lightweighting and miniaturization of internal combustion engines. The multi-functional internal combustion engine piston assembly, built based on the "O"-shaped spring 5, achieves automatic combustion control, eliminating the need for electronic systems to maintain stable combustion. It integrates the piston, motion conversion mechanism, and scavenging function within the cylinder's stroke volume, sharing the motion space and improving the utilization rate of space dimensions or structural materials.

[0016] 2. It is easy to adopt high compression ratios and their mixture compression ignition technology. The combustion environment established by the self-controlled combustion technology of the flexible combustion chamber has good anti-knock properties, and high compression ratios and compression ignition technology can be adopted to avoid non-ignition and unstable combustion. This includes the use of "L"-shaped cross-section non-opening piston rings, which have high sealing performance, can reduce leakage of high-pressure mixtures, and are suitable for compression ignition technology under high compression ratio conditions.

[0017] 3. Adaptable to multiple fuels. Due to the suppression of pressure and temperature that cause detonation by the flexible combustion chamber self-controlled combustion technology, the fuel has low detonation sensitivity and is easy to use with a variety of common fuels.

[0018] 4. It features high power density and high cycle thermal efficiency. In addition to the obvious improvement in power and cycle thermal efficiency due to the use of a high compression ratio, the combined processes generated by the flexible combustion chamber obtain mechanical energy in combustion control and independently participate in the internal combustion engine heating cycle, enabling the heating cycle to obtain additional useful work and increasing the power density and thermal efficiency of the internal combustion engine.

[0019] 5. Improve the overall performance of the internal combustion engine. By adopting a high compression ratio and controlling leakage, the reliability of high-temperature auto-ignition of the compressed mixture is improved, the combustion failure rate is reduced, and the overall working performance is enhanced. Attached Figure Description

[0020] Figure 1 A multi-functional piston assembly for an internal combustion engine Figure 2 O-type spring Figure 3 L-shaped cross-section non-opening piston rings Figure 4 cross Figure 5 Piston skirt Detailed Implementation

[0021] The following detailed description of the embodiments, in conjunction with the accompanying drawings, further illustrates the present invention.

[0022] Figure 1This diagram illustrates a multi-functional piston assembly for a two-stroke internal combustion engine. It includes a piston top 1, a closed piston ring 2, a closed piston ring 3, a piston skirt 4, an O-ring spring 5, a cross-shaped piston 6, a scavenging piston 7, a locating pin 8, and a locating seat 9. The cross-shaped piston 6 has a central section... Figure 4The cylindrical sleeve kinematic pair of the vertical cylinder shaft connects with the motion conversion mechanism to form a motion conversion component. The lower end can be equipped with a two-stroke internal combustion engine scavenging piston 7 or an oil pump, etc., serving as a guide shaft for the reciprocating motion of the piston assembly. The "O"-shaped spring 5 is rigidly connected to the lower locating pin 8. The piston top 1 and piston skirt 4 are rigidly connected, clamping a non-opening piston ring 2 with radial sliding and tight fit with the cylinder liner. A piston ring 3 is also mounted on the piston skirt 4, forming the power piston. At one end of the O-shaped spring 5, the upper locating pin 8 engages in a locating hole groove on the piston skirt 4, causing the "O"-shaped spring 5 to undergo pre-tightening deformation and be fixed to the cross 6. The power piston is elastically connected to the cross 6, and the locating hole groove on the piston skirt 4 sets the working stroke for the "O"-shaped spring 5 under stress deformation. The piston, driven by the compression and rebound of the spring, exhibits a multifunctional composite motion, absorbing, storing, and releasing mechanical energy. It also exhibits characteristics that change with the spring stiffness. The combustion chamber formed by the piston top 1 is a flexible combustion chamber. The volume, temperature, and pressure during combustion follow the spring stiffness variation characteristics, making the combustion process a complex process that changes independently, unaffected by the moving parts. When the multifunctional internal combustion engine piston assembly with the "O"-shaped spring 5 is near the top dead center of the compressed working fluid, and the cross 6 remains relatively stationary, when the force exerted on the "O"-shaped spring 5 by the flexible combustion chamber pressure through the piston top 1 is less than the preload, the "O"-shaped spring 5 does not deform, and the changes in combustion chamber pressure, temperature, and volume follow an adiabatic compression process. When the force exerted on the "O"-shaped spring 5 by the compression and combustion pressures of the flexible combustion chamber through the piston top 1 is greater than the preload, the "O"-shaped spring 5 compresses and deforms, beginning to absorb heat energy and convert it into stored mechanical energy. This blocks the heat accumulation of the combustion chemical reaction, inhibits detonation, and automatically controls combustion or stabilizes combustion according to the spring stiffness variation characteristics. This internal combustion environment overcomes the drawback of uncontrollable combustion pressure during constant-volume heating, providing a high-compression-ratio operating environment. Before the flexible combustion chamber enters the expansion process after combustion, when the force applied to the O-ring 5 by the piston top 1 is less than the rebound force of the O-ring 5, the O-ring 5 begins to release its stored mechanical energy, increasing the internal energy of the working fluid until it returns to its pre-tightened initial state. The characteristics of the decrease in combustion chamber pressure, temperature, and volume follow the change in spring stiffness, unlike the adiabatic expansion process. This process, occurring before the adiabatic expansion process, becomes a way to increase combustion heat rate and power, serving as an efficiency-enhancing mechanism for self-controlled combustion technology. The resulting changes in volume, pressure, and temperature within the flexible combustion chamber, the steady-state mechanical force process, and the flexible combustion thermodynamic process are dynamically matched over a wide range, stably controlling combustion. It is insensitive to ignition phase and fuel properties, employing high-compression-ratio compression ignition technology and adapting to various fuels, providing technical assurance. A technical solution is proposed to improve the power-to-weight ratio of internal combustion engines by obtaining mechanical energy feedback to the working cycle and integrated multifunctional components.

[0023] Figure 2 The “O”-shaped spring 5 is a core component of the flexible combustion chamber and its self-controlled combustion technology. Its slender “O” shape utilizes the reciprocating space of the piston to improve the overall space utilization of the internal combustion engine. The technology involved includes setting the elastic stiffness, preload, and working stroke of the “O”-shaped spring 5 to match the thermodynamic state related to the working range and thermal efficiency of the self-controlled combustion technology.

[0024] Figure 3 The L-shaped, non-opening piston ring 2 is designed to reduce the number of piston rings and to suit high-compression combustion environments. The L-shaped, non-opening piston ring 2 has a large sealing area, resulting in low leakage of high-pressure working fluid, reduced piston friction, and improved piston temperature cooling. Related technologies include the minimum clearance between the L-shaped, non-opening piston ring and the cylinder liner in the cold state of the engine, the thermal expansion interference under different loads, and the appropriate surface contact stress dimensional fit, including thermal fatigue reliability and durability between the sealing surface and the stationary surface.

[0025] Figure 4 The cross 6 shown is a platform integrating multiple components. The cross 6 connects three parties: the lower end is rigidly connected to the scavenging piston 7 and fixed to the O-ring spring 5; the upper end is elastically connected to the power piston through the O-ring spring 5; and the middle connects to the motion mechanism, which can adapt to the needs of special internal combustion engine structures. It includes a 6-degree-of-freedom system with 3 cylindrical sleeve kinematic pairs, which can adapt to three-dimensional or two-dimensional motion mechanisms and replace spherical kinematic pairs.

[0026] Figure 5 The piston skirt 4 is shown. The main focus is on its slotted portion. The spring's working stroke and the flexible combustion chamber's stroke volume are determined by the slot length and the locating pin 8 within the locating pin hole of the cross 6 (see...). Figure 4 The piston skirt 4 presses down on the pre-tensioned "O"-shaped spring 5, and is engaged in the groove of the piston skirt 4 by the upper positioning pin 8 (see...). Figure 1 ).

Claims

1. A multi-functional piston assembly for an internal combustion engine, characterized by The power piston is composed of a piston head 1, a non-opening piston ring 2, a piston ring 3, and a piston skirt 4. The opposed scavenging piston 7 is coaxially assembled at both ends of the cross 6. The piston head 1 and the positioning seat 9 are positioned by the O-shaped spring 5, and the two positioning pins 8 are fixed integrally.

2. The "O" spring 5 of claim 1, wherein The O-shaped spring 5 is an elongated "O" shape, and is elastically deformed along with the reciprocating movement of the multifunctional piston assembly in the cylinder.

3. The splitless piston ring 2 according to claim 1, characterized in that The non-opening piston ring is in the shape of "L" in cross section.

4. The cross 6 according to claim 1, characterized in that The O-shaped spring 5 elastically connects the power piston and rigidly connects the scavenging piston 7, including a cylindrical sleeve kinematic pair that provides six degrees of freedom to connect various reciprocating mechanisms.

5. The piston skirt 4 according to claim 1, characterized in that The piston skirt 4 clamps the non-opening piston ring 2 with the piston head 1. The skirt of the piston skirt 4 is provided with an O-shaped spring 5 spring working stroke hole slot, including a positioning pin 8 in the spring working stroke hole slot, and the piston skirt 4 pre-tightens the O-shaped spring 5.

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