Three-stroke internal combustion engine

Abstract

The invention relates to a three-stroke internal combustion engine. According to the specific design of the three-stroke internal combustion engine, in the air inlet and compression process, the displacement of the circulating piston only occupies half of the stroke; actually, the internal combustion engine is not greatly different from a traditional four-stroke internal combustion engine in overall structure and type, four processes also exist, but only half stroke is occupied by two processes (air inlet and compression), so that the internal combustion engine is called as three strokes (0.5 + 0.5 + 1 + 1 stroke); the invention aims at reducing air intake, reducing pumping loss, reducing fuel consumption, increasing the proportion of combustion and expansion processes and improving heat efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of internal combustion engines, and in particular to a three-stroke internal combustion engine. Background Art

[0002] In 1876, German engineer Nikolaus Otto improved his internal combustion engine design and proposed the Otto cycle; the Otto cycle is a four-stroke cycle, including four processes: intake, compression, combustion and exhaust; the improvement of the Otto cycle internal combustion engine has greatly improved its efficiency and reliability. In 1884, in order to avoid the four-stroke internal combustion engine developed by Otto, British engineer Barratt designed a two-stroke water-cooled two-cylinder gasoline engine. Early Suzuki, Yamaha, Kawasaki, domestic Aideli 100, Xingfu 250, etc., have all been equipped with two-stroke engines.

[0003] After more than 100 years of development, the internal combustion engine has a very mature technology and manufacturing chain. With the emergence of various new technologies (such as homogeneous combustion, turbocharging, variable valves / trachea, variable displacement, exhaust gas preheating and recovery, etc.), the internal combustion engine has become an important power source and is widely used in automobiles, engineering machinery, ships, power generation and other equipment.

[0004] Four-stroke internal combustion engine (such as Figure 1 The engine (as shown) includes four working processes: intake, compression, power generation and exhaust (hence the name "four-stroke"). Each stroke corresponds to half a circle of crankshaft rotation, so the engine performs work once for every 2 circles of crankshaft rotation.

[0005] Two-stroke engines (such as Figure 2 As shown in the figure, the four-stroke internal combustion engine (as shown in the figure) has three valve channels, namely the intake channel, exhaust channel and ventilation channel. The opening and closing of the channels are determined by the movement position of the piston. When the piston moves upward to compress the mixture, the ventilation channel and the exhaust channel will be blocked by the piston and enter a closed state, while the intake channel below remains open. During the upward compression process of the piston, the one-way valve is opened by suction with negative pressure, and the mixture required for the next work is sucked in advance. After the piston compresses and produces work, the piston begins to move downward, the exhaust channel and the ventilation channel enter an open state, and the intake channel is blocked. The downward pressure of the piston causes the internal pressure of the crankcase to increase, and the previously inhaled mixture will enter the combustion chamber along the ventilation channel, while the exhaust gas generated by the previous combustion is squeezed out through the exhaust port. When the piston moves upward again, it can directly perform compression work, and the cycle continues. Whether it is a four-stroke or a two-stroke, the appearance and movement mechanism (such as the core crank-connecting rod mechanism) are relatively similar. But relatively speaking, the two-stroke internal combustion engine is simpler in structure.

[0006] Advantages of two-stroke: shorter working interval (the engine does work once for every crankshaft rotation), greater output power, very fast acceleration, more compact structure, and no need for valve train. These advantages make two-stroke engines very suitable for motorcycles that pursue passion. Disadvantages: 1. Emission problem. The intake and exhaust of the four-stroke engine are relatively independent, so the intake is sufficient and the exhaust is clean. However, the two-stroke engine relies on the new mixed gas to push the exhaust gas out. In the actual operation process, either the exhaust gas is not discharged cleanly, or the clean mixed gas is discharged together; 2. The four-stroke engine can install piston rings on the piston, spray oil when the piston is moving upward, and use the piston rings to scrape the oil when the piston is moving downward to complete the lubrication of the cylinder. However, there are three ventilation channels on the cylinder wall of the two-stroke engine, so the two-stroke engine either mixes gasoline and oil together, or sprays the oil into the crankcase and then enters the combustion chamber. In short, lubrication can only be achieved by burning engine oil, and this lubrication effect is far inferior to that of a four-stroke engine, which greatly shortens the life of the engine.

[0007] The four-stroke engine has mature technology, stable operation and high reliability, and has become the mainstream of internal combustion engines. However, its thermal efficiency needs to be further improved. Summary of the invention

[0008] In order to solve or partially solve the problems existing in the related art, the present application provides a three-stroke internal combustion engine, aiming to improve the thermal efficiency of the internal combustion engine.

[0009] The present application provides a three-stroke internal combustion engine, comprising an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke, wherein the cylinder stroke of the intake stroke and the compression stroke is half of the expansion stroke or the exhaust stroke.

[0010] In some embodiments, the specific working process of the internal combustion engine is:

[0011] (1) Intake stroke: The piston moves downward and the intake valve opens to inject the mixed gas into the cylinder. Then, the piston moves to the middle of the cylinder, i.e. the stop point, and the intake process ends.

[0012] (2) Compression stroke: The piston then moves upward to compress the intake air. When the piston reaches the top of the cylinder, near the top dead center, the spark plug works to ignite the mixture.

[0013] (3) Expansion stroke: The piston is pushed downward to perform expansion work. The piston moves to the bottom of the cylinder, i.e., the bottom dead center, and the expansion process ends.

[0014] (4) Exhaust stroke: The piston moves upward and the exhaust valve opens to exhaust gas. Then, the piston moves to the top dead center, ending a complete working cycle and starting the next cycle.

[0015] In some schemes, during the exhaust stroke, before the piston reaches the top dead center, the intake valve opens in advance so that the intake valve has a certain opening degree at the beginning of the next cycle.

[0016] The technical solution provided by this application may have the following beneficial effects:

[0017] The overall operating scheme of the present invention and its comparison with the traditional four-stroke is that during the intake and compression process, the cyclic piston displacement of the present invention only occupies half of the "stroke", thereby reducing intake, reducing pumping losses, increasing the proportion of combustion and expansion processes, and thus improving the thermal efficiency of the internal combustion engine.

[0018] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects, features and advantages of the present application will become more apparent through a more detailed description of exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0020] Figure 1 It is a schematic diagram of the working process of a four-stroke internal combustion engine;

[0021] Figure 2 It is a schematic diagram of the working process of a two-stroke internal combustion engine;

[0022] Figure 3 The working process of the internal combustion engine cycle of the present application is as follows: (a) intake top dead center; (b) intake stroke; (c) intake end point; (d) compression top dead center (combustion heat release start stage); (e) expansion stroke bottom dead center; (f) exhaust stroke; (g) exhaust top dead center;

[0023] Figure 4 The operating scheme of the application cycle and its comparison with the traditional four-stroke cycle;

[0024] Figure 5 It is a PV comparison diagram of the internal combustion engine cycle of the present application and the traditional four-stroke cycle;

[0025] Figure 6 is another PV comparison diagram of the internal combustion engine cycle of the present application and the conventional four-stroke cycle;

[0026] Figure 7 YesP mi Meaning explanation diagram;

[0027] Figure 8 This is a schematic diagram of the ventilation loss of the four-stroke engine of the present application; DETAILED DESCRIPTION

[0028] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0029] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0030] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0031] Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] In order to improve the thermal efficiency of an internal combustion engine, the present application provides a three-stroke internal combustion engine, including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke, wherein the cylinder stroke of the intake stroke and the compression stroke is half of the expansion stroke or the exhaust stroke.

[0033] In this embodiment, if Figure 3 As shown, the specific working process of the internal combustion engine is:

[0034] (1) Intake stroke: The piston moves downward and the intake valve opens to inject the mixed gas into the cylinder. Then, the piston moves to the middle of the cylinder, i.e. the stop point, and the intake process ends.

[0035] (2) Compression stroke: The piston then moves upward to compress the intake air. When the piston reaches the top of the cylinder, near the top dead center, the spark plug works to ignite the mixture.

[0036] (3) Expansion stroke: The piston is pushed downward to perform expansion work. The piston moves to the bottom of the cylinder, i.e., the bottom dead center, and the expansion process ends.

[0037] (4) Exhaust stroke: The piston moves upward and the exhaust valve opens to exhaust gas. Then, the piston moves to the top dead center, ending a complete working cycle and starting the next cycle.

[0038] like Figure 4 As shown, it can be seen that in the internal combustion engine of the present application, the intake air amount is significantly reduced.

[0039] Figure 5 and Figure 6 It is the PV diagram of the cylinder cycle (P is the pressure in the cylinder, V is the volume in the cylinder), the area enclosed by the PV diagram represents work, "+" represents positive work (the gas does work on the piston), and "-" represents negative work (the piston does work on the gas). That is:

[0040] P mi =(A IMEP -A PMEP ) / Vs

[0041] Among them, Pmi is the indicated pressure, Vs is the cylinder working volume, A IMEP is the area enclosed by positive work, A PMEP is the area enclosed by the pump gas (negative work). Figure 2 Explanation (same principle as PMEP), that is, the average value of the artificially defined pressure (its product with the cylinder volume is equal to the area enclosed by the PV line), which facilitates calculation and definition / comparison of the work capacity of a certain internal combustion engine.

[0042] Figure 7 P mi The meaning of the diagram is explained. It can be seen that the indicated thermal efficiency of the internal combustion engine is calculated by the following formula:

[0043]

[0044] Among them, 3.6×103 is the thermal equivalent of 1kW.h (kJ / (kW.h)), Pi is the indicated power (calculated by the following formula), B is the fuel consumption per hour (kg / h), and Hu is the lower calorific value of the fuel (kJ / kg).

[0045]

[0046] Among them, VS is the cylinder volume, i is the number of cylinders, n is the speed, and τ is the number of strokes.

[0047] Therefore, increasing IMEP or decreasing PMEP and reducing fuel consumption will increase the indicated thermal efficiency of the internal combustion engine.

[0048] In summary, the present application effectively improves the thermal efficiency of the internal combustion engine.

[0049] like Figure 8 As shown, x+yd is the pumping loss, which is the closed area formed by the intersection of intake and exhaust on the PV diagram. This closed area is called pumping loss because the piston needs to do negative work, which is work lost. For example, in the x part of the intake process, the pressure in the cylinder is lower than the atmospheric pressure (P0). At this time, the piston moves downward, and the back pressure (pressure on the back) of the piston is P0. In the forward direction, the pressure on the front is less than the pressure on the back, so negative work is done. Therefore, the internal combustion engine of the present application effectively reduces the pumping loss of the internal combustion engine.

[0050] In some specific embodiments, during the exhaust stroke, before the piston reaches the top dead center, the intake valve is opened in advance so that the intake valve has a certain opening degree when the next cycle starts.

[0051] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A three-stroke internal combustion engine, characterized in that: Including intake stroke, compression stroke, expansion stroke, exhaust stroke, The cylinder stroke of the intake stroke and the compression stroke is half of the expansion stroke or the exhaust stroke.

2. A three-stroke internal combustion engine according to claim 1, characterized in that: The specific working process of the internal combustion engine is: (1) Intake stroke: The piston moves downward and the intake valve opens to inject the mixed gas into the cylinder. Then, the piston moves to the middle of the cylinder, i.e. the stop point, and the intake process ends. (2) Compression stroke: The piston then moves upward to compress the intake air. When the piston reaches the top of the cylinder, near the top dead center, the spark plug works to ignite the mixture. (3) Expansion stroke: The piston is pushed downward to perform expansion work. The piston moves to the bottom of the cylinder, i.e., the bottom dead center, and the expansion process ends. (4) Exhaust stroke: The piston moves upward and the exhaust valve opens to exhaust gas. Then, the piston moves to the top dead center, ending a complete working cycle and starting the next cycle.

3. A three-stroke internal combustion engine according to claim 2, characterized in that: During the exhaust stroke, the intake valve opens in advance before the piston reaches the top dead center, so that the intake valve will be open to a certain degree at the beginning of the next cycle.

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