Intake assembly for an engine, engine, vehicle and method of intake control for an engine

Abstract

The application discloses an engine air intake assembly, an engine, a vehicle and an engine air intake control method, which comprises: a first intake valve with a first intake lift profile; and a second intake valve with different second intake lift profiles, namely, a first profile, a second profile, a third profile and a fourth profile. The first profile is the same as the first intake lift profile; the valve lift and valve opening time of the second profile are less than those of the first intake lift profile; the valve lift of the third profile is less than that of the first intake lift profile; and the valve lift and valve opening time of the fourth profile are less than those of the first intake lift profile. The second intake valve selects the corresponding second intake lift profile to operate under different engine requirements, so that the second intake valve and the first intake valve are asynchronous in air intake, different vortex effects are generated in the cylinder, and different engine cylinder gas flow requirements are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine intake, in particular to an engine intake assembly, an engine, a vehicle and an engine intake control method. BACKGROUND

[0002] To alleviate the energy crisis and environmental pollution, reducing the gas consumption and emissions of the engine is a problem to be solved for the natural gas engine at present, and improving the thermal efficiency of the natural gas engine is the only way to reduce the gas consumption.

[0003] The conventional natural gas engine adopts a premixed ignition mode, wherein the premixed ignition refers to that the fuel and oxygen (or air) are premixed into a uniform mixture. The premixed ignition mode has a high in-cylinder combustion temperature, and the unburned area is easily affected by the high temperature in the cylinder to cause self-ignition, thereby causing engine knock. Adopting a strong tumble combustion system is an effective means to suppress the knock and improve the thermal efficiency of the natural gas engine.

[0004] However, under the background of large cylinder diameter, it is difficult to generate a circumferential vortex motion in the cylinder after using the parallel air duct to construct a strong tumble, so that the tumble effect of the gas in the cylinder is gradually weakened during the combustion process, resulting in a long duration and insufficient combustion in the late combustion stage, thereby causing the problems of high exhaust temperature, high emissions and high gas consumption.

[0005] Therefore, how to provide an engine intake assembly to change the intake effect according to the engine operating condition, so as to generate a vortex in the engine and improve the combustion efficiency of the engine, is a technical problem to be solved by those skilled in the art. SUMMARY

[0006] Therefore, the present application provides an engine intake assembly to change the intake effect according to the engine operating condition, so as to generate a vortex in the engine and improve the combustion efficiency of the engine. In addition, the present application also provides an engine and a vehicle having the above-mentioned engine intake assembly, and an engine intake control method.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0008] An engine intake assembly, comprising:

[0009] A first intake valve having a first intake lift profile;

[0010] The second intake valve has different second intake lift profiles, wherein the different intake lift profiles are respectively: a first profile which is the same as the first intake lift profile; a second profile whose valve maximum opening crank angle is smaller than that of the first intake lift profile, and whose valve lift and valve opening duration are respectively smaller than those of the first intake lift profile; a third profile whose valve lift is smaller than that of the first intake lift profile; and a fourth profile whose valve maximum opening crank angle is larger than that of the first intake lift profile, and whose valve lift and valve opening duration are respectively smaller than those of the first intake lift profile.

[0011] Preferably, in the above intake assembly, the first intake lift profile and the third profile are both early-opening and late-closing profiles.

[0012] Preferably, in the above intake assembly, the second profile is an early-opening and early-closing profile.

[0013] Preferably, in the above intake assembly, the fourth profile is a late-opening and late-closing profile.

[0014] Preferably, in the above intake assembly, the valve lift of the second profile, the valve lift of the third profile and the valve lift of the fourth profile are the same.

[0015] An engine comprising an intake assembly, wherein the intake assembly is any one of the above-described intake assemblies.

[0016] Preferably, in the above engine,

[0017] When the engine is in a first working condition, the first intake valve of the engine operates in the first intake lift profile, and the second intake valve operates in the first profile;

[0018] When the engine is in a second working condition, the first intake valve of the engine operates in the first intake lift profile, and the second intake valve operates in the second profile;

[0019] When the engine is in a third working condition, the first intake valve of the engine operates in the first intake lift profile, and the second intake valve operates in the third profile;

[0020] When the engine is in a fourth working condition, the first intake valve of the engine operates in the first intake lift profile, and the second intake valve operates in the fourth profile.

[0021] Preferably, in the engine, the torque of the engine in the first working condition and the torque of the engine in the third working condition are both greater than the torque of the engine in the second working condition;

[0022] and the torque of the engine in the second working condition is greater than the torque of the engine in the fourth working condition;

[0023] The rotating speed of the engine in the first working condition is greater than the rotating speed of the engine in the third working condition.

[0024] A vehicle comprising an engine, wherein the engine is any one of the above-mentioned engines.

[0025] An air intake control method of an engine, applied to any one of the above-mentioned engines, comprising:

[0026] defining the working conditions of the engine: when the rotating speed of the engine is greater than a and the torque of the engine is greater than b, the engine is in the first working condition; when the torque of the engine is greater than c and not greater than b, the engine is in the second working condition; when the rotating speed of the engine is not greater than a and the torque of the engine is greater than b, the engine is in the third working condition; when the torque of the engine is not greater than c and greater than zero, the engine is in the fourth working condition, wherein b is greater than c;

[0027] obtaining the rotating speed and the torque of the engine, and determining the working condition of the engine;

[0028] According to the working condition of the engine, the profile of the second intake valve is switched to operate, and the first profile, the second profile, the third profile and the fourth profile are all the profiles of the operation of the second intake valve.

[0029] In the embodiment of the present application, an air intake assembly of an engine is disclosed, wherein the second intake valve has different second intake lift profiles, and the second intake valve selects a corresponding second intake lift profile to operate when the engine has different requirements, so that the second intake valve and the first intake valve can realize asynchronous air intake and generate different gas flow effects in the cylinder to meet different gas flow requirements of the engine in the cylinder. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0031] Figure 1 The structure diagram of the air intake assembly of the engine disclosed in the embodiment of the present application;

[0032] Figure 2An intake lift profile of an intake valve of an intake assembly disclosed in embodiments of the present application;

[0033] Figure 3 A universal working condition division diagram of an engine disclosed in embodiments of the present application;

[0034] Figure 4 A flow chart of an intake control method of an engine disclosed in embodiments of the present application. DETAILED DESCRIPTION

[0035] The present application discloses an intake assembly of an engine to change the intake effect according to the engine working condition, generate vortex in the engine, and improve the combustion efficiency of the engine. In addition, the present application also discloses an engine and a vehicle with the above-mentioned intake assembly of the engine, and an intake control method of the engine.

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0037] Hereinafter, the terms "first" and "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features.

[0038] To alleviate the energy crisis and environmental pollution, reducing the gas consumption and emissions of the engine is a problem to be solved for natural gas engines at present, and improving the thermal efficiency of the natural gas engine is the only way to reduce the gas consumption.

[0039] The conventional natural gas engine adopts a premixed ignition mode, in which the premixed ignition refers to that the fuel and oxygen (or air) are premixed into a uniform mixture. The in-cylinder combustion temperature is high in the premixed ignition mode, and the unburned area is easily affected by the high temperature in the cylinder to cause self-ignition, thereby causing engine knock. Adopting a strong tumble combustion system is an effective means to suppress the knock and improve the thermal efficiency of the natural gas engine.

[0040] However, under the background of large cylinder diameter, it is difficult to generate a circumferential vortex motion in the cylinder after using the parallel air duct to construct a strong tumble, so that the tumble effect of the gas in the cylinder gradually weakens during the in-cylinder combustion process. Due to the low turbulent kinetic energy of the circumferential edge in the cylinder, the flame development speed slows down in the late stage, resulting in long combustion duration and incomplete combustion in the late stage, thereby causing the problems of high exhaust temperature, high emissions and high gas consumption.

[0041] In addition, different operating conditions of the natural gas engine have different requirements for the gas flow in the cylinder, and the traditional intake form is difficult to meet the requirements of the gas flow in the cylinder under all operating conditions of the engine.

[0042] It should be noted that tumble flow and vortex flow are two different forms of gas flow. Vortex flow is a organized gas flow around the cylinder axis generated during the engine intake process, which is divided into intake vortex, compression vortex and combustion vortex; while tumble flow is a specific flow pattern formed by the gas in the cylinder, which is mainly realized by the design of the intake port and the combustion chamber.

[0043] Based on the above technical problems, the engine intake assembly disclosed by the embodiments of the present application is as shown in the figure. Figure 1 As shown in the figure, the engine intake assembly comprises a first intake valve 10, a second intake valve 20, a cylinder head 30 and a piston 40.

[0044] The first intake valve 10 and the second intake valve 20 are both connected with the cylinder head 30, and the cylinder head 30 and the piston 40 form a combustion chamber 5, and the first intake valve 10 and the second intake valve 20 can be in communication with the combustion chamber 5.

[0045] The first intake valve 10 comprises a first intake valve port 11 and a first intake valve rod 12, and the second intake valve 20 comprises a second intake valve port 21 and a second intake valve rod 22.

[0046] The first intake valve port 11 and the second intake valve port 21 are both in communication with the combustion chamber 5, the first intake valve rod 12 is installed in the first intake valve port 11 and controls the opening degree of the first intake valve port 11, and the second intake valve rod 22 is installed in the second intake valve port 21 and controls the opening degree of the second intake valve port 21.

[0047] The piston 40 can move along the height direction relative to the cylinder head 30, so as to realize different strokes of the engine, wherein the piston 40 has an intake stroke of the engine in the process of moving away from the cylinder head 30 along the height direction with the rotation of the crankshaft, and the engine can realize intake into the combustion chamber 5 through the first intake valve 10 and the second intake valve 20 in the intake stroke. It can be understood that the first intake valve port 11 and the second intake valve port 21 are in an open state in the intake stroke of the engine.

[0048] In different working conditions of the engine of the embodiments of the present application, the first intake valve rod 12 opens the first intake valve port 11 at the same opening degree and time in the intake stroke. In different working conditions of the natural gas engine, the second intake valve rod 22 opens the second intake valve port 21 at different opening degrees and times in the intake stroke. It can be understood that the second intake valve 20 has different opening angles, opening times and opening sizes to adapt to the requirements of vortex flow in different working conditions of the natural gas engine, so as to improve the combustion efficiency of the engine.

[0049] As Figure 2 shown, the first intake valve 10 has a first intake lift profile, the black line in the figure.

[0050] The second intake valve 20 has a different second intake lift profile, wherein the intake lift profile is divided into: a first profile (black in the figure), a second profile (red in the figure), a third profile (blue in the figure) and a fourth profile (green in the figure), and the four profiles correspond to different valve opening angles and closing angles.

[0051] The first profile is the same as the first intake lift profile. Exemplarily, the crankshaft rotation angle range of the first profile valve in the open state is 0° to 20°.

[0052] The crankshaft rotation angle at the maximum opening of the second profile valve is smaller than that of the first intake lift profile. The valve lift of the second profile is smaller than that of the first intake lift profile. The valve opening duration of the second profile is shorter than that of the first intake lift profile. Exemplarily, the crankshaft rotation angle range of the second profile valve in the open state is 1° to 14°.

[0053] The valve lift of the third profile is smaller than that of the first intake lift profile. Exemplarily, the crankshaft rotation angle range of the third profile valve in the open state is 0° to 20°.

[0054] The crankshaft rotation angle at the maximum opening of the fourth profile valve is greater than that of the first intake lift profile. The valve lift of the fourth profile is smaller than that of the first intake lift profile. The valve opening duration of the fourth profile is shorter than that of the first intake lift profile. Exemplarily, the crankshaft rotation angle range of the third profile valve in the open state is 7° to 20°.

[0055] The second intake valve of the intake assembly of the engine of the embodiment has a different second intake lift profile, and the second intake valve selects the corresponding second intake lift profile to operate under different requirements, so that the second intake valve and the first intake valve can realize asynchronous intake and produce different gas flow effects in the cylinder, meeting the different cylinder gas flow requirements of the engine.

[0056] In addition, due to the strong tumble flow and weak vortex flow generated in the cylinder, the post-combustion speed can be improved, the knock can be suppressed, the exhaust temperature can be reduced, and the engine economy and reliability can be improved.

[0057] Figure 2As shown in the figure, the crankshaft rotation angle corresponding to the piston top dead center is about 3°, and the crankshaft rotation angle corresponding to the piston bottom dead center is about 18°. In combination with the crankshaft rotation angle range of the valve opening state of the first type line, the second type line, the third type line and the fourth type line, it can be known that the first type line is an early opening and late closing type line, the second type line is an early opening and early closing type line, the third type line is an early opening and late closing type line, and the fourth type line is a late opening and late closing type line.

[0058] In the embodiments of the present application, early opening refers to that the intake valve is opened in advance before the piston reaches the top dead center, so that the negative pressure generated by the piston descending can be used to make the intake more smooth, reduce the intake resistance and increase the intake volume. Late closing refers to that the intake valve is closed after the piston reaches the bottom dead center, so that the inertia of the intake airflow can be fully utilized to continue to charge the cylinder, thereby improving the intake efficiency. In combination with the effects of early opening and late closing, the second intake valve adopts the intake mode of the first type line, and the first intake valve adopts the early opening and late closing intake mode, which can meet the requirements of smooth intake and intake volume of the engine. It should be noted that the early opening and late closing intake mode can prolong the intake time.

[0059] In the embodiments of the present application, the early closing of early opening and late closing refers to that the intake valve is closed before the piston reaches the bottom dead center. The second intake valve adopts the early opening and late closing intake mode of the second type line, and the first intake valve adopts the early opening and late closing intake mode, so that the intake processes of the first intake valve and the second intake valve are different, which can meet the requirement of small fuel demand of the engine in the later period.

[0060] In the embodiments of the present application, the second intake valve adopts the early opening and late closing intake mode of the third type line, and the first intake valve adopts the early opening and late closing intake mode, which can meet the requirements of smooth intake and intake volume of the engine, and achieve the purpose of suppressing engine knock.

[0061] In the embodiments of the present application, the late opening of late opening and late closing refers to that the intake valve is opened after the piston reaches the top dead center. The second intake valve adopts the late opening and late closing intake mode, and the first intake valve adopts the early opening and late closing intake mode, which can meet the requirements of increasing the combustion speed of the engine and reducing the cylinder backflow in the initial stage of intake.

[0062] In some embodiments, the valve lift of the second type line, the valve lift of the third type line and the valve lift of the fourth type line are the same.

[0063] It should be noted that the valve lift of the second type line, the valve lift of the third type line and the valve lift of the fourth type line, and the valve lift of the first type line can be set according to different requirements, and are within the protection scope.

[0064] Exemplarily, the first intake valve 10 can be provided with a first intake lift profile, and the second intake valve 20 can be provided with a first profile, a second profile, a third profile and a fourth profile. The first intake lift profile of the first intake valve 10 can be achieved by the convex shape of the cam of the first intake valve driving connection; the first profile, the second profile, the third profile and the fourth profile of the second intake valve 20 can be achieved by the convex shape of the cam of the second intake valve driving connection. By switching the convex position of the cam, the second intake valve 20 can be driven to achieve the corresponding second intake lift profile.

[0065] In addition, the application further discloses an engine comprising the intake assembly, wherein the intake assembly is the intake assembly disclosed in the above embodiments, and therefore the engine with the intake assembly also has all the technical effects described above, which will not be repeated here.

[0066] The engine of the application can switch the second intake valve to the corresponding second intake lift profile according to the working condition requirement under different working conditions. Exemplarily, when the engine is in a first working condition, the first intake valve of the engine operates with a first intake lift profile, and the second intake valve operates with a first profile; when the engine is in a second working condition, the first intake valve of the engine operates with a first intake lift profile, and the second intake valve operates with a second profile; when the engine is in a third working condition, the first intake valve of the engine operates with a first intake lift profile, and the second intake valve operates with a third profile; and when the engine is in a fourth working condition, the first intake valve of the engine operates with a first intake lift profile, and the second intake valve operates with a fourth profile.

[0067] The shapes of the first intake lift profile, the first profile, the second profile, the third profile and the fourth profile can be referred to the description in Figure 2 , which will not be repeated here.

[0068] It should be noted that the first working condition herein is a high-speed and high-load working condition, the second working condition is an intermediate-load working condition, the third working condition is a low-speed and high-load working condition, and the fourth working condition is a low-load working condition. Figure 3 Figure 3 Figure 3

[0069] The torque of the engine in the first working condition and the torque of the engine in the third working condition are both greater than the torque of the engine in the second working condition; the torque of the engine in the second working condition is greater than the torque of the engine in the fourth working condition; and the speed of the engine in the first working condition is greater than the speed of the engine in the third working condition.

[0070] The dividing speed of the high speed and the low speed of the engine is a, the dividing torque of the high load torque and the intermediate load torque is b, and the dividing torque of the intermediate load torque and the low load torque is c. The specific values of a, b and c are determined based on performance calibration.

[0071] ​​​For example, the current engine speed is 600 r / min-1900 r / min, the value range of a is 1300 r / min-1400 r / min, the value range of b is about 75% of the rated torque of the engine, and the value range of c is about 25% of the rated torque of the engine. For other contents in this article, refer to the data relationship.

[0072] Under the high-speed and high-load working condition of the engine, the engine intake amount is large, and the in-cylinder flow is strong. At this time, the engine thermal efficiency is mainly affected by the smoothness of the intake. Based on this, the engine of the embodiment of the present application needs to ensure that the first intake valve and the second intake valve both have sufficient intake time under the high-speed and high-load working condition of the engine to ensure the smoothness of the engine intake. Therefore, the second intake valve operates with the first profile. It can be understood that, under the high-speed and high-load working condition of the engine, the second intake valve operates with the first profile and the first intake valve operates with the first intake lift profile, which can ensure that the first intake valve and the second intake valve have sufficient intake time and can both smoothly intake, thereby ensuring the stable operation of the engine. For example, the intake rates of the first intake valve and the second intake valve are the same, which realizes the symmetrical intake of the cylinder of the engine.

[0073] Under the medium-load working condition of the engine, the engine intake amount is small, and the in-cylinder flow is weak. At this time, the speed is slow in the late stage of in-cylinder combustion, which easily causes long afterburning time, low engine thermal efficiency, long emission time, and high gas consumption. Based on this, the embodiment of the present application needs to increase the difference between the first intake valve lift and the second intake valve lift to improve the swirl ratio under the medium-load working condition of the engine, and needs to reduce the late-stage intake amount in the engine cylinder. Therefore, the second intake valve operates with the second new profile. It can be understood that, under the medium-load working condition of the engine, the second intake valve operates with the second profile and the first intake valve operates with the first intake lift profile, which can reduce the late-stage intake amount in the engine cylinder and avoid long afterburning time. It can also improve the swirl ratio and solve the problems of low thermal efficiency and long emission time.

[0074] Under the low-speed and high-load working condition of the engine, the engine intake amount is moderate, but due to the high temperature in the cylinder in this region, knock easily occurs. The engine thermal efficiency is affected not only by the smoothness of the intake, but also by the influence of the in-cylinder combustion speed on knock. Based on this, the engine of the embodiment of the present application needs to ensure sufficient intake time and increase the difference between the first intake valve lift and the second intake valve lift to improve the swirl ratio under the low-speed and high-load working condition of the engine, so as to achieve the purpose of accelerating the fuel combustion speed and suppressing knock. It can be understood that, under the low-speed and high-load working condition of the engine, the second intake valve operates with the third profile and the first intake valve operates with the first intake lift profile, so that the engine has sufficient intake time, and the first intake valve lift and the second intake valve lift have a difference to improve the swirl ratio, thereby achieving the purpose of suppressing knock.

[0075] The engine is in a low load working condition, the engine intake volume is small, the in-cylinder flow is weak, and there is negative pressure in the intake pipe due to the small throttle opening. Backflow occurs at the initial stage of the intake valve opening, which further deteriorates the combustion speed. Based on this, the engine of the embodiment of the application needs to delay the opening angle of the second intake valve to build vortex under the low load working condition, so as to improve the combustion speed and reduce the in-cylinder backflow at the initial stage of intake. It can be understood that: under the low load working condition, the second intake valve operates in the fourth type line, the first intake valve operates in the first intake lift type line, and the opening angle of the second intake valve is delayed, so that vortex is generated when the second intake valve is opened, so as to improve the combustion speed and reduce the in-cylinder backflow at the initial stage of intake.

[0076] Based on the above analysis, the engine of the embodiment of the application selects different second intake lift type lines for the second intake valve under different working conditions, so that the first intake valve and the second intake valve are different in intake, so that vortex is formed in the engine at the different intake positions of the first intake valve and the second intake valve, and the combustion efficiency of the engine is improved. In addition, the above-mentioned method does not affect the effect of the engine tumble flow, and avoids the problem of reduced tumble intensity caused by using airway structure change to generate vortex.

[0077] It should be noted that the engine in some embodiments is a natural gas engine.

[0078] In addition, a vehicle is protected in the present application, which includes an engine, and the engine is the engine disclosed in the above-mentioned embodiments, therefore, the vehicle with the engine also has all the technical effects mentioned above.

[0079] As Figure 4 shown, the embodiment of the application also discloses an engine intake control method, which includes the following steps: it should be noted that Figure 4 the second intake valve in the above-mentioned embodiment is the second intake valve in the present application,

[0080] S1: defining the working condition of the engine.

[0081] During the operation of the engine, according to the speed and torque request of the engine, the dividing speed between high speed and low speed of the engine is defined as a, the dividing torque between large load torque and intermediate load torque is defined as b, and the dividing torque between intermediate load torque and low load torque is defined as c. Wherein, the specific values of a, b and c are determined based on performance calibration.

[0082] Wherein, when the engine speed is greater than a and the torque is greater than b, the engine is in a high speed and high load condition, which is also referred to as a first condition herein; when the engine speed is not greater than a and the torque is greater than b, the engine is in a low speed and high load condition, which is also referred to as a third condition herein; when the engine torque is not greater than b and is greater than c, the engine is in an intermediate load condition, which is also referred to as a second condition herein; when the engine torque is not greater than c but is greater than zero, the engine is in a low load condition, which is also referred to as a fourth condition herein.

[0083] S2: pre-storing the condition information of the engine.

[0084] The speed and torque information corresponding to the high speed and high load condition, the low speed and high load condition, the intermediate load condition and the low load condition of the engine are pre-stored in the control system of the engine.

[0085] S3: obtaining the running information of the engine.

[0086] After detecting the start of the engine, the speed and torque during the running of the engine are obtained.

[0087] S4: determining the running condition of the engine and switching the operation profile of the second intake valve of the engine.

[0088] If the torque during the running of the engine is not greater than zero, the engine is in a motoring condition, and the second intake valve of the engine executes a first profile.

[0089] If the torque during the running of the engine is greater than b and the speed during the running of the engine is greater than a, the engine is in the first condition, and the second intake valve of the engine executes the first profile.

[0090] If the torque during the running of the engine is greater than b and the speed during the running of the engine is not greater than a, the engine is in the third condition, and the second intake valve of the engine executes a third profile.

[0091] If the torque during the running of the engine is not greater than b and is greater than c, the engine is in the second condition; wherein b is greater than c, and the second intake valve of the engine executes a second profile.

[0092] If the torque during the running of the engine is not greater than c, the engine is in the fourth condition, and the second intake valve of the engine executes a fourth profile.

[0093] It should be noted that the first profile, the second profile, the third profile and the fourth profile are all the operation profiles of the second intake valve, and the shapes thereof can be referred to the description in Figure 1 , and the engine has a structure for implementing different second intake lift profiles of the second intake valve, which is not specifically limited herein.

[0094] In the high-speed and high-load working condition of the engine, the second intake valve operates with the first profile and the first intake valve operates with the first intake lift profile, so that the first intake valve and the second intake valve have sufficient intake time and can smoothly intake, thereby ensuring stable operation of the engine.

[0095] In the medium-load working condition of the engine, the second intake valve operates with the second profile and the first intake valve operates with the first intake lift profile, so that the intake amount of the engine at the late stage can be reduced, the long combustion time at the late stage can be avoided, the swirl ratio can be improved, and the problems of low thermal efficiency and long emission time can be solved.

[0096] In the low-speed and high-load working condition of the engine, the second intake valve operates with the third profile and the first intake valve operates with the first intake lift profile, so that the engine has sufficient intake time, and the lift of the first intake valve and the lift of the second intake valve have a difference to improve the swirl ratio, thereby achieving the purpose of suppressing knock.

[0097] In the low-load working condition of the engine, the second intake valve operates with the fourth profile and the first intake valve operates with the first intake lift profile, so that the opening angle of the second intake valve is delayed, thereby generating swirl when the second intake valve is opened, thereby achieving the purpose of improving the combustion speed and reducing the in-cylinder backflow amount at the initial stage of intake.

[0098] It can be known from the above analysis that, in different working conditions, the engine of the embodiment of the application selects different second intake lift profiles for the second intake valve, so that the first intake valve and the second intake valve have differential intake, thereby forming swirl in the engine at the differential intake positions of the first intake valve and the second intake valve, improving the combustion efficiency of the engine. In addition, the above-mentioned mode does not affect the effect of tumble flow of the engine, and avoids the problem of reduced tumble flow intensity caused by changing the air passage structure to generate swirl.

[0099] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts of each embodiment can be referred to each other.

[0100] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An air intake assembly for an engine, characterized by, The intake assembly comprises: a first intake valve having a first intake lift profile; a second intake valve having a second intake lift profile different from the first intake lift profile, wherein the different intake lift profiles are respectively: a first profile identical to the first intake lift profile; a second profile having a smaller valve maximum opening crank angle than the first intake lift profile, and having a smaller valve lift and a smaller valve opening duration than the first intake lift profile; a third profile having a smaller valve lift than the first intake lift profile; and a fourth profile having a larger valve maximum opening crank angle than the first intake lift profile, and having a smaller valve lift and a smaller valve opening duration than the first intake lift profile.

2. The air intake assembly of claim 1, wherein, The first intake lift profile and the third profile are both early-opening and late-closing profiles.

3. The air intake assembly of claim 2, wherein, The second profile is an early-opening and early-closing profile.

4. The air intake assembly of claim 3, wherein, The fourth profile is a late-opening and late-closing profile.

5. The air intake assembly of any one of claims 1 to 4, wherein, The valve lift of the second profile, the valve lift of the third profile, and the valve lift of the fourth profile are identical.

6. An engine comprising an air intake assembly, characterised in that, The intake assembly is the intake assembly according to any one of claims 1 to 5.

7. The engine according to claim 6, wherein, when the engine is in a first operating condition, the first intake valve of the engine operates with the first intake lift profile, and the second intake valve operates with the first profile; when the engine is in a second operating condition, the first intake valve of the engine operates with the first intake lift profile, and the second intake valve operates with the second profile; when the engine is in a third operating condition, the first intake valve of the engine operates with the first intake lift profile, and the second intake valve operates with the third profile; when the engine is in a fourth operating condition, the first intake valve of the engine operates with the first intake lift profile, and the second intake valve operates with the fourth profile.

8. The engine of claim 7, wherein the torque of the engine in the first operating condition and the torque of the engine in the third operating condition are both greater than the torque of the engine in the second operating condition; and the torque of the engine in the second operating condition is greater than the torque of the engine in the fourth operating condition; the speed of the engine in the first operating condition is greater than the speed of the engine in the third operating condition.

9. A vehicle comprising an engine, characterized by The engine is the engine according to any one of claims 6 to 8.

10. An intake control method of an engine applied to the engine according to any one of claims 6 to 8, characterized by, The method comprises: defining operating conditions of the engine: when the speed of the engine is greater than a and the torque of the engine is greater than b, the engine is in a first operating condition; when the torque of the engine is greater than c and not greater than b, the engine is in a second operating condition; when the speed of the engine is not greater than a and the torque of the engine is greater than b, the engine is in a third operating condition; when the torque of the engine is not greater than c and greater than zero, the engine is in a fourth operating condition, wherein b is greater than c; acquiring the speed and the torque of the engine, and determining the operating condition of the engine; According to the operating condition of the engine, the profile of the second intake valve of the engine is switched, the first profile, the second profile, the third profile and the fourth profile are all the profiles of the second intake valve.

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