Engine, power assembly and vehicle

Abstract

The invention discloses an engine, a power assembly and a vehicle. The engine comprises a shell, a piston and an air inlet valve, and the shell is provided with a combustion cavity and an air inlet channel communicated with the combustion cavity; the air inlet valve is movably arranged between the combustion cavity and the air inlet channel. The piston is movably arranged in the combustion cavity, when the piston moves to a preset position, the air inlet valve is closed, the compression ratio of the engine is A, the expansion ratio of the engine is B, A is larger than or equal to 8.6 and smaller than or equal to 14.2, and B is larger than or equal to 15 and smaller than or equal to 18. According to the technical scheme, when the piston moves to the preset position, the air inlet valve is closed, so that the expansion ratio of the engine is two times of the compression ratio of the engine in the limit state and is far larger than the compression ratio of the engine under the normal working condition, the acting stroke of fuel is prolonged, the combustion efficiency of the fuel is improved, and the oil consumption of the engine is reduced; the economic performance of the engine is improved.

Description

Technical Field

[0001] This application relates to the field of engine technology, specifically to an engine, powertrain, and vehicle. Background Technology

[0002] The Atkinson cycle engine is a special type of internal combustion engine. Unlike the Otto cycle engine, which has the same compression and expansion ratios, the Atkinson cycle engine, during the gas compression phase, can delay the closing time of the intake valves through a connecting rod mechanism or a variable valve timing (VVT) system. This allows some of the gas in the combustion chamber to be pushed back into the intake manifold. The reduced gas volume in the combustion chamber lowers the engine's compression ratio, lengthens the piston's expansion stroke, and results in more complete and efficient fuel combustion.

[0003] The timing of intake valve closing is closely related to the engine's compression ratio. How to close the intake valve at the right time to improve the combustion efficiency of fuel in the combustion chamber has become an urgent problem to be solved in the industry. Summary of the Invention

[0004] The purpose of this application is to provide an engine, powertrain, and vehicle that aims to solve the problem of low combustion efficiency in engines in the related art.

[0005] To achieve the objectives of this application, in a first aspect, this application provides an engine, the engine including a housing, a piston, and an intake valve, the housing having a combustion chamber and an intake passage communicating with the combustion chamber; the intake valve is movably disposed between the combustion chamber and the intake passage;

[0006] The piston is movably disposed within the combustion chamber. When the piston moves to a preset position, the intake valve closes, and at this time the compression ratio of the engine is A, the expansion ratio of the engine is B, 8.6≤A≤14.2, 15≤B≤18.

[0007] In one possible implementation, when the piston moves to a preset position, the volume of the space formed by the piston and the cavity wall of the combustion chamber is C, and the maximum expansion volume of the engine is D, where 0.5≤C / D≤0.9.

[0008] In one possible implementation, the volume of the space formed by the piston and the wall of the combustion chamber is C, where 200ml≤C≤700ml.

[0009] In one possible implementation, the engine further includes a crankshaft connected to the piston;

[0010] When the piston moves to the preset position, the rotation angle of the crankshaft is E, a≤E≤b, 580°≤a≤600°, 630°≤b≤650°.

[0011] In one possible implementation, the expansion ratio of the engine is B, where B = 15.5, B = 16, or B = 16.5.

[0012] In one possible implementation, the piston is movably disposed within the combustion chamber along a first direction, the piston's stroke in the first direction is F, the length of the combustion chamber along a second direction is G, F > G, and the second direction is perpendicular to the first direction.

[0013] In one possible implementation, the piston's stroke along the first direction is F, and the length of the combustion chamber along the second direction is G, where 1.27 ≤ F / G ≤ 1.29.

[0014] In one possible implementation, the housing also has an exhaust duct that communicates with the combustion chamber;

[0015] The engine also includes a catalyst and an exhaust gas recirculation assembly, the catalyst being connected to the exhaust manifold;

[0016] The air inlet of the exhaust gas recirculation assembly is connected to the catalyst and the exhaust duct, and the air outlet of the exhaust gas recirculation assembly is connected to the combustion chamber.

[0017] In one possible implementation, the engine further includes an ignition coil for converting the low-voltage current of the battery into a high-voltage current available to the spark plugs; the energy value of the ignition coil is G, 100mj≤H≤140mj.

[0018] In one possible implementation, the housing also has a lubrication channel for the passage of lubricating fluid;

[0019] The engine also includes a fully variable oil pump and a pressure sensor, the pressure sensor being located within the lubrication channel and used to detect the pressure within the lubrication channel;

[0020] The fully variable oil pump is used to regulate the pressure of the lubricating fluid in the lubrication channel.

[0021] Secondly, this application also proposes a powertrain, the powertrain including an engine, the engine including a housing, a piston and an intake valve, the housing having a combustion chamber and an intake duct communicating with the combustion chamber; the intake valve is movably disposed between the combustion chamber and the intake duct;

[0022] The piston is movably disposed within the combustion chamber. When the piston moves to a preset position, the intake valve closes, and at this time the compression ratio of the engine is A, the expansion ratio of the engine is B, 8.6≤A≤14.2, 15≤B≤18.

[0023] Thirdly, this application also proposes a vehicle, the vehicle including a powertrain, the powertrain including an engine, the engine including a housing, a piston and an intake valve, the housing having a combustion chamber and an intake duct communicating with the combustion chamber; the intake valve is movably disposed between the combustion chamber and the intake duct;

[0024] The piston is movably disposed within the combustion chamber. When the piston moves to a preset position, the intake valve closes, and at this time the compression ratio of the engine is A, the expansion ratio of the engine is B, 8.6≤A≤14.2, 15≤B≤18.

[0025] The technical solution of this application closes the intake valve when the piston moves to a preset position, thereby making the engine's expansion ratio twice the engine's compression ratio under extreme conditions and much greater than the engine's compression ratio under normal operating conditions. This extends the power stroke of the fuel, improves fuel combustion efficiency, reduces engine fuel consumption, and improves the engine's economic performance. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 A cross-sectional view of one embodiment of the engine provided in this application;

[0028] Figure 2 This is a three-dimensional structural schematic diagram of one embodiment of the engine provided in this application.

[0029] Explanation of reference numerals in the attached figures:

[0030] 100-Engine;

[0031] 1-Shell casing, 11-Combustion chamber, 12-Intake duct, 13-Exhaust duct;

[0032] 2-Intake valve, 21-Intake camshaft, 22-Variable valve timing system;

[0033] 3-Piston, 4-Catalyst, 5-Exhaust Gas Recirculation Assembly, 6-Fully Variable Oil Pump, 7-Pressure Sensor. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] It should be noted that when a component is said to be "fixed" to another component, it can be directly on the other component or it can be in a middle component. When a component is said to be "connected" to another component, it can be directly connected to the other component or it may be in a middle component.

[0036] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.

[0037] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0038] For ease of understanding, the relevant technical terms involved in the embodiments of this application will be explained and described below.

[0039] Top dead center: The highest point the piston can reach in the combustion chamber. At this point, the volume of the space enclosed by the piston and the combustion chamber is at its minimum.

[0040] Bottom dead center: The lowest point the piston can reach in the combustion chamber. At this point, the space enclosed by the piston and the combustion chamber has the largest volume.

[0041] Compression ratio: The degree to which fuel and gas are compressed in the combustion chamber as the piston moves from bottom dead center to top dead center.

[0042] Expansion ratio: The ratio of the volume of the space formed by the piston and the combustion chamber when the piston is at bottom dead center to the volume of the space formed by the piston and the combustion chamber when the piston is at top dead center.

[0043] Atkinson cycle engine: The traditional engine (Otto cycle engine) operates primarily through the intake, compression, power, and exhaust phases. Intake phase: The exhaust valve in the combustion chamber opens, and the piston, driven by the crankshaft, moves from top dead center (TDC) to bottom dead center (BDC). The pressure in the combustion chamber decreases, and external fuel and air enter the combustion chamber through the intake manifold. Compression phase: The intake valve closes, and the piston, driven by the crankshaft, moves from BDC to TDC, compressing the fuel in the combustion chamber. Power phase: When the piston reaches TDC, the spark plug ignites, igniting the fuel in the combustion chamber. The high pressure generated by fuel combustion pushes the piston towards BDC. Exhaust phase: When the piston reaches BDC, the exhaust valve opens, and the piston, driven by the crankshaft, moves upward, pushing the exhaust gases from the combustion chamber outward through the exhaust valve and exhaust manifold.

[0044] The Atkinson cycle engine operates on the same principle as the Otto cycle engine in its intake, power, and exhaust phases. However, unlike the Otto cycle, during the compression phase, the intake valve does not close immediately when the piston begins its upward movement from bottom dead center (BDC); there is a delay. Therefore, as the piston moves from BDC to CDC, it pushes some fuel from the combustion chamber back into the intake manifold. The total volume of compressible fuel decreases, while the piston's distance between BDC and CDC remains constant. Consequently, the engine's expansion ratio remains unchanged, and the final compressed volume of fuel remains the same. The reduced compression ratio of the piston to the fuel increases the work done per unit volume of fuel (in an Otto cycle engine, one part fuel might do one part work; in an Atkinson cycle engine, because some fuel is expelled from the combustion chamber, it may require two-thirds of the fuel to do one part work). This longer fuel-work time results in more complete combustion.

[0045] Therefore, it can be seen that the timing of intake valve closing is closely related to the engine's compression ratio. How to close the intake valve at the appropriate time to improve the combustion efficiency of fuel in the combustion chamber has become an urgent problem to be solved in the industry.

[0046] To address the aforementioned problems, this application proposes a vehicle that can be a gasoline-powered vehicle or a hybrid vehicle. The vehicle can be a sedan, an SUV, or a truck; this application makes no limitation in this regard.

[0047] The vehicle includes a body, wheels, and a powertrain. The body serves as the vehicle's supporting frame, providing support and connection for the various assembly components. The wheels are rotatably connected to the body; there can be two, three, or four wheels, and this application does not impose any limitation on this. The powertrain is housed within the body and is driven by the wheels. The powertrain drives the wheels to rotate, thereby propelling the vehicle.

[0048] The powertrain includes an engine and a transmission. The engine, as the power source of the powertrain, transmits its power to the wheels via the transmission, thus driving the vehicle forward. The engine can be a gasoline engine or a diesel engine; this application makes no limitation on this. The transmission connects the engine and the wheels, and can regulate the wheel speed and thus the vehicle speed by adjusting the torque exerted by the engine on the wheels.

[0049] The engine includes a housing, a piston, and an intake valve. The housing has a combustion chamber and an intake manifold communicating with the combustion chamber. The intake valve is movably disposed between the combustion chamber and the intake manifold. The piston is movably disposed within the combustion chamber and can reciprocate linearly under the impetus of fuel within the combustion chamber. This reciprocating linear motion drives the crankshaft, thereby driving the vehicle. When the piston reaches a preset position, the intake valve closes, and at this time, the engine's compression ratio is A, the engine's expansion ratio is B, and 8.6 ≤ A ≤ 14.2, 15 ≤ B ≤ 18.

[0050] The technical solution of this application closes the intake valve when the piston moves to a preset position, thereby making the engine's expansion ratio twice the engine's compression ratio under extreme conditions and much greater than the engine's compression ratio under normal operating conditions. This extends the power stroke of the fuel, improves fuel combustion efficiency, reduces engine fuel consumption, and improves the engine's economic performance.

[0051] The engine provided in this application will now be described in detail with reference to the accompanying drawings.

[0052] Please refer to Figure 1 The engine 100 includes a housing 1, which serves as the main connecting body of the engine 100, supporting and connecting the various component assemblies of the engine 100. The housing 1 forms a combustion chamber and an intake duct 12 and an exhaust duct 13 that communicate with the combustion chamber. The intake duct 12 is used to draw in fuel and air during the intake phase of the engine 100, and the exhaust duct 13 is used to discharge the exhaust gas from the combustion chamber during the exhaust phase of the engine 100.

[0053] The engine 100 also includes a piston 3 and a crankshaft. Part of the piston 3 is located inside the combustion chamber, while another part extends out of the combustion chamber and is connected to the crankshaft. The piston 3 converts the heat energy from the combustion of fuel and gas in the combustion chamber into the kinetic energy of its own reciprocating motion, thereby driving the crankshaft to rotate. The crankshaft is connected to the wheels via a transmission, and it converts the reciprocating linear motion of the piston 3 into rotational motion, thereby driving the wheels to rotate.

[0054] In one embodiment of this application, the piston 3 is movably disposed within the combustion chamber along a first direction, the stroke of the piston 3 in the first direction is F, and the length of the combustion chamber along a second direction is G, where F > G. The second direction is perpendicular to the first direction. The axial length of the combustion chamber is greater than its radial length. This configuration has several advantages: First, the increased axial length of the combustion chamber can further improve the expansion ratio of the engine 100, thereby increasing the fuel combustion efficiency of the engine 100. Second, the larger shaft-to-diameter ratio of the combustion chamber 11 allows for a more slender shape, ensuring a smaller surface area of ​​the combustion chamber for the same displacement. This reduces the contact area between the fuel and the combustion chamber, increases the thermal resistance between the fuel and the combustion chamber, reduces fuel heat loss, and improves fuel thermal efficiency. Third, the larger shaft-to-diameter ratio of the combustion chamber 11 makes it more compact, shortening the distance the flame travels to the end of the air-fuel mixture, thereby reducing combustion time, increasing volumetric efficiency, improving the combustion efficiency of the engine 100, and reducing the possibility of combustion chamber explosion. Fourthly, a larger shaft-to-diameter ratio will also increase the movement speed of piston 3, improve the turbulence of the air-fuel mixture, accelerate the combustion speed of fuel, and improve the thermal efficiency of engine 100. In particular, when 1.27≤F / G≤1.29 and F / G=1.28, the combustion efficiency of engine 100 can reach its maximum.

[0055] The engine 100 also includes an intake valve 2, which is movably disposed between the intake duct 12 and the combustion chamber. When the intake valve 2 is open, the intake duct 12 is connected to the combustion chamber 11, and when the intake valve 2 is closed, the connection between the intake duct 12 and the combustion chamber is disconnected.

[0056] Please refer to Figure 2 To control the opening and closing of the intake valve 2, the engine 100 also includes an intake camshaft 21 and a connecting rod mechanism. The intake camshaft 21 is connected to the crankshaft of the engine 100 and can rotate under the drive of the crankshaft. Multiple cams are mounted on the intake camshaft 21. The connecting rod mechanism connects the cams and the intake valve 2, and is used to convert the rotational motion of the cams into the linear motion of the intake valve 2 opening and closing. The connecting rod mechanism can be a rocker combination or a rocker and slider combination; this application does not limit this. When the intake camshaft 21 rotates, the rotation of the intake camshaft 21 can be transmitted to the connecting rod mechanism through the cams, and then to the intake valve 2 through the connecting rod mechanism, thereby controlling the opening and closing of the intake valve 2. By designing the wrap angle of the cams, the timing of the opening and closing of the intake valve 2 can be controlled.

[0057] To achieve precise control over the opening and closing timing of the intake valve 2, the engine 100 also includes a variable valve timing system 22. The variable valve timing system 22 can change the opening and closing timing of the valves by changing the relative angle between the intake camshaft 21 and the crankshaft of the engine 100.

[0058] In this application, the cam wrap angle design of the intake camshaft 21 gives the intake valve 2 a first delay angle, and the variable valve timing system 22, through a rear lock design, gives the intake valve 2 a second delay angle. Under the combined action of the first and second delay angles, the intake valve 2 can be delayed in closing only after the piston 3 has moved upward from the bottom dead center to a preset position. At this time, the compression ratio of the engine 100 is A, the expansion ratio of the engine 100 is B, 8.6≤A≤14.2, 15≤B≤18. The expansion ratio of the engine 100 is twice the compression ratio of the engine 100 under extreme conditions, and is also much greater than the compression ratio of the engine 100 under normal operating conditions. This extends the power stroke of the fuel, improves the combustion efficiency of the fuel, reduces the fuel consumption of the engine 100, and improves the economic performance of the engine 100. Specifically, when B=15.5, B=16, or B=16.5, the combustion chamber has a sufficient working stroke to ensure complete combustion of fuel, while also taking into account the working time of piston 3, avoiding excessively long working cycles of piston 3 that would affect the output efficiency of engine 100.

[0059] There are various ways in which the piston 3 can move. In one embodiment of this application, the volume of the space formed by the piston 3 and the combustion chamber wall is C, and the maximum expansion volume of the engine 100 is D. It should be noted that the volume of the space formed by the piston 3 and the combustion chamber wall refers to the volume formed by the side of the piston 3 facing the top of the combustion chamber when the piston 3 is moving between top dead center and bottom dead center, and this volume changes continuously with the position of the piston 3. The maximum expansion volume of the engine 100 refers to the volume formed by the side of the piston 3 facing the top of the combustion chamber when the piston 3 moves to bottom dead center, and the combustion chamber wall. The ratio C / D of the volume of the space formed by the piston 3 and the combustion chamber wall to the maximum expansion volume of the engine 100 reflects the movement position of the piston 3 within the combustion chamber 11. Therefore, in this application, the controller of engine 100 will use a sensor installed in combustion chamber 11 to detect the position of piston 3 in real time. When 0.5≤C / D≤0.9, it means that piston 3 has moved to the preset position, and the controller will control the intake valve 2 to close, so that the compression ratio of engine 100 is A and the expansion ratio of engine 100 is B, which satisfy 8.6≤A≤14.2 and 15≤B≤18, thereby improving the combustion efficiency of engine 100.

[0060] To reduce the computational load and detection difficulty of the controller, the controller can also directly detect the volume of the space formed by the piston 3 and the cavity wall of the combustion chamber. In one embodiment of this application, the volume of the space formed by the piston 3 and the cavity wall of the combustion chamber is C. When 200ml≤C≤700ml, the controller will also determine that the piston 3 has reached the preset position, and then control the intake valve 2 to close, so that the compression ratio of the engine 100 is A and the expansion ratio of the engine 100 is B, which satisfies 8.6≤A≤14.2 and 15≤B≤18, thereby improving the combustion efficiency of the engine 100.

[0061] Understandably, piston 3 is connected to crankshaft, and the movement position of piston 3 is related to the rotation angle of crankshaft. Therefore, in addition to detecting the position of piston 3 itself, the position of piston 3 can also be detected by the rotation of crankshaft. Specifically, in one embodiment of this application, the rotation angle of crankshaft is E. Considering that the crankshaft needs to rotate two revolutions, or 720°, to complete one stroke cycle (i.e., from the intake stage to the exhaust stage), 0° to 720° is used as the crankshaft rotation angle. In this embodiment, when the controller detects that the crankshaft rotation angle has rotated to a≤E≤b, 580°≤a≤600°, and 630°≤b≤650°, the controller will also determine that piston 3 has moved to the preset position. At this time, the controller will control the intake valve 2 to close, so that the compression ratio of engine 100 is A and the expansion ratio of engine 100 is B, satisfying 8.6≤A≤14.2 and 15≤B≤18, thereby improving the combustion efficiency of engine 100. Compared to directly detecting the position of piston 3, the sensor for obtaining the crankshaft rotation angle is less expensive to install and can be shared with other systems of engine 100 (such as the ignition system and fuel injection system). The crankshaft position sensor is usually installed outside engine 100, where the operating environment is relatively stable and less affected by the high temperature, high pressure and vibration inside engine 100, resulting in better reliability.

[0062] Engine 100 also includes a catalytic converter 4 and an exhaust gas recirculation (EGR) assembly 5. One end of the catalytic converter 4 is connected to the combustion chamber via an exhaust passage to receive the exhaust gases produced in the combustion chamber. The other end is connected to the vehicle's exhaust pipe. The catalytic converter 4 is used to convert harmful gases produced by fuel in the combustion chamber, such as carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons (HC), into harmless substances, such as carbon dioxide (CO2), water (H2O), and nitrogen (N2), which are then emitted to the outside through the exhaust pipe, thereby improving the vehicle's environmental performance.

[0063] The exhaust gas recirculation (EGR) assembly 5 has its inlet connected to the catalyst 4, and its outlet connected to the combustion chamber. The EGR assembly 5 is used to reintroduce a portion of the exhaust gas into the engine 100's intake system to reduce the temperature of the combustion chamber 11 and decrease the oxygen concentration, thereby reducing the possibility of fuel knocking within the combustion chamber. In one embodiment of this application, the EGR assembly 5's inlet is connected to the junction of the catalyst 4 and the exhaust manifold 13, meaning the EGR assembly 5 takes gas from the front end of the catalyst 4. Since the gas has not yet come into contact with the catalyst carrier layer within the catalyst 4, the gas pressure loss is minimal. Taking gas at this location effectively increases the intake pressure of the EGR assembly 5, increases the intake volume of the EGR assembly 5, and improves the intake efficiency of the EGR assembly 5. Through testing and calculation, by taking gas from the front end of the catalytic converter 4, the gas intake rate of the exhaust gas recirculation component 5 (the proportion of the gas entering the recirculation component to the exhaust weight in the exhaust duct 13) can reach 25%, which improves the utilization rate of exhaust gas and enhances the economy of the engine 100.

[0064] The engine 100 also includes spark plugs and ignition coils. The ignition coils convert the low-voltage electricity from the vehicle's power battery into high-voltage electricity and supply it to the spark plugs. The spark plugs introduce the high-voltage electricity transmitted by the ignition coils into the combustion chamber, thereby igniting the fuel-air mixture in the combustion chamber and pushing the piston 3 downward.

[0065] In one embodiment of this application, the ignition coil is a high-energy ignition coil with an energy value of G, where 100mJ ≤ H ≤ 140mJ. This ignition coil implements high-energy ignition technology, which is a technique that significantly increases ignition energy (such as temperature, magnetic field, and electric field) to improve combustion rate and combustion completeness, expand the air-fuel ratio and combustible range of the mixture, and improve engine performance. This application employs high-energy ignition technology to generate a strong discharge in the combustion chamber within a very short time, enhancing spark intensity, promoting flame core formation, and enabling rapid and complete combustion of the air-fuel mixture, thereby improving the combustion efficiency and power output of the engine.

[0066] The housing 1 also forms a lubrication channel through which lubricating fluid flows to various components of the engine 100 for lubrication and cooling. The engine 100 also includes a fully variable oil pump 6 and a pressure sensor 7. The pressure sensor 7 is located within the lubrication channel and is used to detect the pressure within the lubrication channel. The fully variable oil pump 6 is used to regulate the pressure of the lubricating fluid within the lubrication channel. In practical applications, the engine 100 controller can adjust the duty cycle of the fully variable oil pump 6 based on the pressure of the lubricating oil within the lubrication channel obtained by the pressure sensor 7. This ensures that the pressure value of the lubricating oil within the lubrication channel always follows a calibrated and locked preset target value (i.e., the most suitable pressure value for the engine 100 under the current operating conditions). This avoids both excessive pressure in the lubrication channel, which would waste energy, and insufficient pressure, which would affect the lubrication effect on the engine 100.

[0067] In the description of the embodiments of this application, it should be noted that the orientation or positional relationship of the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and other indicators are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0068] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art will understand that all or part of the processes for implementing the above embodiments and equivalent variations made in accordance with the claims of this application are still within the scope of this application.

Claims

1. An engine, characterized in that, The device includes a housing, a piston, and an intake valve. The housing has a combustion chamber and an intake passage communicating with the combustion chamber. The intake valve is movably disposed between the combustion chamber and the intake passage. The piston is movably disposed within the combustion chamber. When the piston moves to a preset position, the intake valve closes, and at this time the compression ratio of the engine is A, the expansion ratio of the engine is B, 8.6≤A≤14.2, 15≤B≤18.

2. The engine as claimed in claim 1, characterized in that, When the piston moves to the preset position, the volume of the space formed by the piston and the cavity wall of the combustion chamber is C, and the maximum expansion volume of the engine is D, 0.5≤C / D≤0.

9.

3. The engine as described in claim 2, characterized in that, The volume of the space formed by the piston and the wall of the combustion chamber is C, where 200ml≤C≤700ml.

4. The engine as claimed in claim 1, characterized in that, The engine also includes a crankshaft connected to the piston; When the piston moves to the preset position, the rotation angle of the crankshaft is E, a≤E≤b, 580°≤a≤600°, 630°≤b≤650°.

5. The engine as claimed in claim 1, characterized in that, The expansion ratio of the engine is B, where B = 15.5, B = 16, or B = 16.

5.

6. The engine as claimed in claim 1, characterized in that, The piston is movably disposed within the combustion chamber along a first direction, the stroke of the piston in the first direction is F, the length of the combustion chamber along a second direction is G, F > G, and the second direction is perpendicular to the first direction.

7. The engine as claimed in claim 6, characterized in that, The piston's stroke along the first direction is F, and the length of the combustion chamber along the second direction is G, where 1.27 ≤ F / G ≤ 1.

29.

8. The engine as claimed in claim 1, characterized in that, The housing also has an exhaust duct, which is connected to the combustion chamber; The engine also includes a catalyst and an exhaust gas recirculation assembly, the catalyst being connected to the exhaust manifold; The air inlet of the exhaust gas recirculation assembly is connected to the catalyst and the exhaust duct, and the air outlet of the exhaust gas recirculation assembly is connected to the combustion chamber.

9. The engine as claimed in claim 1, characterized in that, The engine also includes an ignition coil for converting the low-voltage current of the battery into a high-voltage current usable by the spark plugs; the energy value of the ignition coil is G, 100mj≤H≤140mj.

10. The engine as claimed in claim 1, characterized in that, The housing also has a lubrication channel for the passage of lubricating fluid; The engine also includes a fully variable oil pump and a pressure sensor, the pressure sensor being located within the lubrication channel and used to detect the pressure within the lubrication channel; The fully variable oil pump is used to regulate the pressure of the lubricating fluid in the lubrication channel.

11. A powertrain, characterized in that, Includes the engine as described in any one of claims 1 to 10.

12. A vehicle, characterized in that, Including the powertrain as described in claim 11.

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